Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Yuji Oshima Last modified date:2020.04.24

Professor / Animal and Marine Bioresource Sciences / Department of Bioresource Sciences / Faculty of Agriculture


Papers
1. Mst Ruhina Margia Khanam, Yohei Shimasaki, Michito Tsuyama, Hiroshi Goto, Xuchun Qiu, Koki Mukai, Yuji Oshima., Presumption of toxic mechanism of tributyltin on photosystem in marine diatoms by comparison to diuron as a reference agent through chlorophyll a fluorescence transient analysis, apanese Journal of Environmental Toxicology22: 13-29, doi.org/10.11403/jset.22.13, 2019.12.
2. Xuchun Qiu, Koki Mukai, Yohei Shimasaki, Min Wu, Chen Chen, Yijiang Lu, Hirofumi Ichinose, Takashi Nakashima, Yoko Kato-Unoki, Yuji Oshima, Diurnal variations in expression of photosynthesis-related proteins in the harmful Raphidophyceae Chattonella marina var. antiqua, Journal of Experimental Marine Biology and Ecology, 10.1016/j.jembe.2020.151361, 527, 2020.06, Many biological features of Chattonella species display diurnal oscillations, but little is known about the corresponding cellular responses at the proteome level. In the present study, we hypothesized that the abundance of certain proteins would periodically fluctuate to suit the diurnal changes of biological processes in Chattonella cells. To test this hypothesis, we undertook proteomic analysis over 7 time points covering a 24-h period in C. marina var. antiqua cells at early stationary phase (12:00, 17:00, 20:00, 24:00 on day 8, and 05:00, 08:00, 12:00 on the following day). The protein profiles of C. marina var. antiqua cells collected from the diurnal cycle shared a majority of common protein spots. However, the expression of 16 out of 124 detected spots exhibited significant differences between light and dark periods and/or over the 7 time points of the diurnal cycle. The proteins of OEE, Cyt c553, and AtpB showed significantly higher expression levels in the light period, and generally were maximally expressed during the period of 12:00–17:00. The proteins of GAPDH and RPL12 generally showed higher expression levels in the dark period, and were maximally expressed during the period of 20:00–24:00. These findings support our hypothesis, and suggest that the periodic expressions of these proteins may be critical either for optimal cell utilization of resources or to maintain proper cell function throughout diurnal cycles..
3. Xuchun Qiu, Yukihiko Matsuyama, Mitsuhiro Furuse, Yohei Shimasaki, Yuji Oshima, Effects of Chattonella antiqua on the swimming behavior and brain monoamine metabolism of juvenile yellowtail (Seriola quinqueradiata), Marine Pollution Bulletin, 10.1016/j.marpolbul.2020.110896, 152, 2020.03, Being the precursor of serotonin and melatonin, dietary supplementation with tryptophan (TRP) may modulates behavior, stress responses, and antioxidant capacity in fish. In this study, effects of Chattonella exposure on the swimming behavior and brain monoamine metabolism of yellowtail fed a commercial diet (control diet) or that enriched by 1.5% L-TRP (TRP + diet) were investigated. A 7-day dietary TRP supplementation elevated spontaneous swimming speed of yellowtail and mitigated their behavioral response to Chattonella (250 cells/mL) exposure. A 30-day dietary TRP supplementation elevated growth of juvenile yellowtail. Lethal exposure to Chattonella (1000 cells/mL) significantly elevated the turnover rates of serotonin, dopamine, and norepinephrine metabolism in fish fed control diet, but did not alter the serotonin turnover rate in fish fed TRP + diet. Our results suggested that dietary supplementation with TRP had potential to mitigate the stress response in yellowtail to Chattonella, partly via mediating their brain monoamine metabolism..
4. Xuchun Qiu, Sang Gyoon Kim, Ikjoon Kang, Takeshi Hano, Yohei Shimasaki, Yuji Oshima, Combined toxicities of tributyltin and polychlorinated biphenyls on the development and hatching of Japanese medaka (Oryzias latipes) embryos via in ovo nanoinjection, Chemosphere, 10.1016/j.chemosphere.2019.03.104, 927-934, 2019.06, Tributyltin (TBT) and polychlorinated biphenyls (PCBs) are typical organic pollutants that co-exist in the aquatic environment. Despite increasing awareness of their combined impacts, knowledge about their potential interactive effects remains limited. In this study, we investigated the effects of TBT-PCBs mixtures on the survival, development, and hatching of embryos of Japanese medaka (Oryzias latipes). Our goal was to assess the interactive effects of TBT and PCBs on early-life-stage fish. We used in ovo nanoinjection to simulate the maternal transfer process and to control exposure doses at 0, 7.5, 15, 30 ng/g-egg (for both toxins). A factorial design (4 × 4) corresponding to the above doses was used to define the formulation of mixtures. Results showed that injection of mixtures of TBT and PCBs into fertilized eggs caused significantly elevated rates of mortality, yolk-sac shrinkage, swim-up failure, and deformities of medaka embryos/larvae. TBT and PCBs interacted synergistically to induce the above developmental abnormalities. In contrast, exposure to only TBT increased the hatching times of embryos, whereas exposure to only PCBs decreased the hatching times. The dose ratios, dose levels, and interactive effect of TBT and PCBs in a mixture played significant roles in determining the final impact on time-to-hatching. Our results suggested that in ovo exposure to a mixture of TBT and PCBs may interact synergistically to induce developmental abnormalities in fishes..
5. Xuchun Qiu, Naoto Iwasaki, Kun Chen, Yohei Shimasaki, Yuji Oshima, Tributyltin and perfluorooctane sulfonate play a synergistic role in promoting excess fat accumulation in Japanese medaka (Oryzias latipes) via in ovo exposure, Chemosphere, 10.1016/j.chemosphere.2018.12.191, 220, 687-695, 2019.04, The ubiquitous environmental obesogens tributyltin (TBT) and perfluorooctane sulfonate (PFOS) may accumulate in parent and be transferred to their offspring, resulting in trans-generational adverse effects. In this study, we investigated the combined toxic and obesogenic effects of TBT and PFOS on the early life stages of Japanese medaka (Oryzias latipes). In ovo nanoinjection was used to simulate the maternal transfer process. Doses were controlled at 0, 0.05, 0.5, and 2.5 ng/egg (TBT) and at 0, 0.05, 0.5, and 5.0 ng/egg (PFOS), with a full factorial design for mixture formulations. Relatively high doses of agents in mixtures were needed to induce significant mortality (TBT ≥ 0.5 ng/egg) or delayed hatching (PFOS = 5.0 ng/egg) of embryos. The interaction between TBT and PFOS in mixtures had significant effects on the observed hatching delay, but not on acute mortality. Compared with controls, separate exposure to TBT (or PFOS) notably elevated adipose areas at the doses of 0.05 and 0.5 ng/egg, but not at the highest doses. Combined exposure significantly promoted the fat accumulation in newly hatched larvae, even when the doses of TBT and PFOS were both at the levels that did not show obesogenic effect. The interactive effect of TBT and PFOS could aggravate the total obesogenic effect of their mixtures, indicating a synergistic interaction. These results highlight the importance of paying close attention to interaction effects when addressing the impacts of mixtures of environmental obesogens..
6. Koki Mukai, Yohei Shimasaki, Xuchun Qiu, Yoko Kato-Unoki, Kun Chen, Mst Ruhina Margia Khanam, Yuji Oshima, Effects of light and hydrogen peroxide on gene expression of newly identified antioxidant enzymes in the harmful algal bloom species Chattonella marina, European Journal of Phycology, 10.1080/09670262.2019.1576062, 2019.01, Antioxidant enzymes are essential proteins that maintain cell proliferation potential by protecting against oxidative stress. They are present in many organisms including harmful algal bloom (HAB) species. We previously identified the antioxidant enzyme 2-Cys peroxiredoxin (PRX) in the raphidophyte Chattonella marina. This enzyme specifically decomposes a hydrogen peroxide (H 2 O 2 ). PRX is the only antioxidant enzyme so far identified in C. marina. This study used mRNA-seq, using Trinity assemble and blastx for annotation, to identify a further five antioxidant enzymes from C. marina: Cu Zn superoxide dismutase (Cu/Zn-SOD), glutathione peroxidase (GPX), catalase (CAT), ascorbate peroxidase (APX) and thioredoxin (TRX). In the gene expression analysis of six enzymes (Cu/Zn-SOD, GPX, CAT, APX, TRX and PRX) using light-acclimated (100 μmol photons m −2 s −1 ) C. marina cells, only PRX gene expression levels were significantly increased by strong light irradiation (1000 μmol photons m −2 s −1 ). H 2 O 2 concentration and scavenging activity were also increased and significantly positively correlated with PRX gene expression levels. In dark-acclimated cells, expression levels of all antioxidant enzymes except APX were significantly increased by light irradiation (100 μmol photons m −2 s −1 ). Expression decreased the following day, with the exception of PRX expression. With the exception of CAT, gene expression of antioxidant enzymes was not significantly induced by artificial H 2 O 2 treatment, although average gene expression levels were slightly increased in some enzymes. Thus, we suggest that light is the main trigger of gene expression, but the resultant oxidative stress is also a possible factor affecting the gene expression of antioxidant enzymes in C. marina..
7. Yoko Kato-Unoki, Yuki Takai, Masato Kinoshita, Toshitaka Mochizuki, Ryohei Tatsuno, Yohei Shimasaki, Yuji Oshima, Genome editing of pufferfish saxitoxin- and tetrodotoxin-binding protein type 2 in Takifugu rubripes, Toxicon, 10.1016/j.toxicon.2018.08.001, 153, 58-61, 2018.10, The pufferfish saxitoxin- and tetrodotoxin-binding protein 2 (PSTBP2), which is involved in toxin accumulation, was knocked out in Takifugu rubripes embryos by using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 genome-editing technology. Treating the embryos with one of two single-guide RNA (sgRNA) resulted in mutation rates of 57.1% and 62.5%, respectively, as estimated using a heteroduplex mobility assay at 3 days postfertilization. Both sgRNAs might induced frameshift mutations that knocked out the T. rubripes PSTBP2..
8. Rumana Tasmin, Yohei Shimasaki, Michito Tsuyama, Xuchun Qiu, Fatma Khalil, Koki Mukai, Mst Ruhina Margia Khanam, Naotaka Yamada, Shinji Fukuda, Ikjoon Kang, Yuji Oshima, Effects of water temperature and light intensity on the acute toxicity of herbicide thiobencarb to a green alga, Raphidocelis subcapitata, Environmental Science and Pollution Research, 10.1007/s11356-018-2599-5, 25, 25, 25363-25370, 2018.09, The present study investigated how principal environmental factors such as temperature and light intensity change the toxicological properties of thiobencarb (TB) herbicide to the green alga, Raphidocelis subcapitata. At first, we investigated the inhibitory effect of TB (0, 15.6, 31.2, 62.4, and 125 μg L−1) on growth of R. subcapitata at five temperatures (10, 15, 20, 25, or 30 °C) for 144 h exposure and calculated 72- and 144-h effective concentration values (EC10, 20, and EC50) for growth rate. All EC values significantly decreased with an increasing temperature. The maximum quantum yield of photosystem II in R. subcapitata exposed to 125 μg L−1 of TB was also significantly inhibited with increased temperature. These physiological effects could explain the lower EC values at high temperatures. Then, single and interactive effects of TB, temperature, and light intensity on growth rate were investigated by three-way of analysis of variance. As a result, single and interactive effects were detected in all explanatory variables. These results suggest that temperature and light intensity change the acute toxicity parameter in R. subcapitata exposed to TB and must be considered in evaluating the risk of TB..
9. M. Honda, X. Qiu, J. Koyama, S. Uno, S. L. Undap, Y. Shimasaki, Y. Oshima, Wharf roach Ligia sp: A novel environmental indicator for polycyclic aromatic hydrocarbons contamination at coastal area., Int J Environ Res, 12, 1-11, 2018.03.
10. Masato Honda, Xuchun Qiu, Jiro Koyama, Seiichi Uno, Suzanne Lydia Undap, Yohei Shimasaki, Yuji Oshima, The Wharf Roach, Ligia sp., A Novel Indicator of Polycyclic Aromatic Hydrocarbon Contamination in Coastal Areas, International Journal of Environmental Research, 10.1007/s41742-017-0063-x, 12, 1, 2018.03, We investigated polycyclic aromatic hydrocarbon (PAH) pollution of the intertidal and supratidal zone using the wharf roach (Ligia sp.) as a novel environmental indicator. PAH and alkylated PAH (alkPAH) concentrations in wharf roaches collected from nine sampling sites on the central and northern coast of Japan in November 2011 were analyzed. Total alkPAH concentrations were higher than those of PAHs at all sampling sites. Seven sampling sites had relatively low total concentrations of PAHs and alkPAHs (57.7–130 and 276–770 ng/g-dry, respectively); they included sites in Miyagi Prefecture (St. 5 and 9) that were seriously damaged by the Great East Japan Earthquake and by the following Tsunami on 11 March 2011. Two sampling sites (St. 2: Kominato, Aomori Prefecture; St. 3: Usushiri, Hokkaido) had higher concentrations of total PAHs and alkPAHs (PAHs, 1025 and 591 ng/g-dry, respectively; alkPAHs, 1490 and 1160 ng/g-dry, respectively). Diagnostic ratio calculation showed that St. 2 and 3 had PAHs of pyrolytic origin, possibly from vehicle exhaust gas or industrial fuel combustion, or both. The concentrations of these pollutants in the wharf roach were similar to those in bivalves and therefore likely reflected PAH pollution at the collection sites. The wharf roach may be a suitable candidate indicator of PAH pollution, not only in the intertidal zone inhabited by the currently used bivalve indicators, but also in the supratidal zone..
11. Mukai, K., Teramoto, A., Qiu, X., Shimasaki, Y., Kato-Unoki, Y., Lee, J.M., Mizoguchi, N., Khanam, M.R.M., Satone, H., Tatsuke, T.,Kusakabe, T., Oshima, Y.,, Gene structure and cDNA sequence of 2-Cys peroxiredoxin in the harmful algal bloom species Chattonella marina and its gene transcription under different light intensities., European Journal of Phycology, 10.1080/09670262.2017.1346206, 53, 29-38, 2018.01.
12. Khalil, F., Qiu, X., Kang, I.J., Abo-Ghanema, I., Shimasaki, Y., Oshima, Y.,, Comparison of social behavior responses of Japanese medaka ( Oryzias latipes ) to lethal and sublethal chlorpyrifos concentrations at different exposure times., Ecotoxicology and Environmental Safety, 10.1016/j.ecoenv.2017.07.007, 145, 78-82, 2018.01.
13. Honda, M., Muta, A., Shimazaki, A., Akasaka, T., Yoshikuni, M., Shimasaki, Y., Oshima, Y.,, High concentrations of perfluorooctane sulfonate in mucus of tiger puffer fish Takifugu rubripes: a laboratory exposure study., Environ Sci Pollut Res Int, 10.1007/s11356-017-0537-6, 186, 133-138, 2018.01.
14. Qiu, X., Tanoue, W., Kawaguchi, A., Yanagawa, T., Seki, M., Shimasaki, Y., Honjo, T., Oshima, Y.,, Interaction patterns and toxicities of binary and ternary pesticide mixtures to Daphnia magna estimated by an accelerated failure time model. Sci. Total Environ. . doi:10.1016/j.scitotenv.2017.07.034, Sci. Total Environ., 10.1016/j.scitotenv.2017.07.034, 607-608, 367-374, 2018.01, Organisms in natural environments are often exposed to a broad variety of chemicals, and the multi-chemical mixtures exposure may produce significant toxic effects, even though the individual chemicals are present at concentrations below their no-observed-effect concentrations. This study represents the first attempt that uses the accelerated failure time (AFT) model to quantify the interaction and toxicity of multi-chemical mixtures in environmental toxicology. We firstly conducted the acute immobilization tests with Daphnia magna exposed to mixtures of diazinon (DZN), fenitrothion (MEP); and thiobencarb (TB) in single, binary, and ternary formula- tions, and then fitted the results to the AFT model. The 48-h EC50 (concentration required to immobilize 50% of the daphnids at 48 h) values for each pesticide obtained from the AFT model are within a factor of 2 of the cor- responding values calculated from the single pesticide exposure tests, indicating the methodology is able to pro- vide credible toxicity values. The AFT model revealed either significant synergistic (DZN and MEP; DZN and TB) or Daphnia magna.
15. Masato Honda, Hiroaki Gunjikake, Shigeaki Matsut, Xuchun Qiu, Yohei Shimasaki, Yuji Oshima, Effect of repeated Exposure to low oxygen on respiratory metabolism and vertical movements in the pen shell Atrina lischkeana, Journal of the Faculty of Agriculture, Kyushu University, 62, 2, 387-392, 2017.09, We exposed pen shells (Atrina lischkeana) to repeated periods of low-oxygen for 30 d and measured their survival, behavior, glycogen content, and organic acid concentration. Exposure to low-oxygen had no effect on survival. Animals moved upward above the sediment under low-oxygen conditions and downward under aerobic conditions, repeating these movements for 19 d. The difference in shell height above the sediment before and after low-oxygen exposure gradually decreased; after 20 d there was no significant difference. Low-oxygen exposure also resulted in a significant decrease in glycogen content and in concentrations of malate and fumarate. Thus, repeated exposure of pen shells to low-oxygen conditions reduces glycogen content, alters metabolism, and affects vertical movements, all of which may cause ecological dysfunction. We suggest that hypoxia might be one factor contributing to the collapse of pen shell resources..
16. Xuchun Qiu, Kokl Mukai, Yohei Shimasaki, Michito Tsuyama, Tadashi Matsubara, Takashi Nakashima, Hirofumi Ichinose, Yu Nakajima, Ibuneo Honjo, Yuji Oshima, Variations in the expression of photosynthesis-related proteins in field Chattonella marina cells during a harmful algal bloom, Journal of the Faculty of Agriculture, Kyushu University, 62, 2, 373-380, 2017.09, Time series variations in protein expression profiles in field Chattonella marina cells were investigated during a HAB occurred in the inner part of Ariake Sea, Japan (5-14 September, 2012). This study aimed to gather information on the molecular mechanisms underlying the physiological responses in field C. marina population during HAB. Proteomic analysis showed that the abundance of -37% protein spots (40 out of 108 detected from 2-DE gel images) significantly varied with the sampling date. Significant decreases in the abundances of proteins involved in photosystem II (LHCP 4), electron transfer chain (Cyt c553), Calvin cycle (GAPDH), and chloroplast antioxidant system (2-Cys Prx) were observed as the bloom progressed, suggesting the efficiencies of those photosynthetic pathways declined during the bloom. In addition, the abundances of the above proteins showed significant positive correlations with the Fv/Fm ratio and growth rate of C. marina and with DIN concentrations (except LHCP 4). Our findings suggested that declined expressions of those photosynthesis-related proteins presented some molecular foundation of the decreases in Fv/Fm ratio and growth rate of C. marina during the bloom, and also provided insight into mechanistic links between the external/internal factors and physiological responses of C. marina that may ultimately dictate the ecology of the bloom..
17. Chen K, Tsutsumi Y, Yoshitake S, Qiu X, Xu H, Hashiguchi Y, Honda M, Tashiro K, Nakayama K, Hano T, Suzuki N, HayakawaK, Shimasaki Y, Oshima Y., Alteration of development and gene expression induced by in ovo-nanoinjection of 3-hydroxybenzo[c]phenanthrene into Japanese medaka (Oryzias latipes) embryos., Aquatic Toxicology, 182, 194-204, 2017.06.
18. Satone H, Nonaka S, Lee JM, Shimasaki Y, Kusakabe T, Kawabata S, Oshima Y., Tetrodotoxin and tributyltin-binding abilities of recombinant pufferfish saxitoxin and tetrodotoxin binding proteins of Takifugu rubripes., Toxicon. 125:50-52(2017), 125, 50-52, 2017.06.
19. Sekiguchi, T., Kuraku, S., Tatsumi, K., Shimasaki, Y., Oshima, Y., Suzuki, N.,, Identification and Molecular Characterization of the Stanniocalcin Family Gene from the Inshore Hagfish, Eptatretus burgeri., Journal of the Faculty of Agriculture, Kyushu University,, 62, 93-98, 2017.06.
20. Khanam, M.R.M., Shimasaki, Y., Hosain, M.Z., Mukai, K., Tsuyama, M., Qiu, X., Tasmin, R., Goto, H., Oshima, Y.,, Diuron causes sinking retardation and physiochemical alteration in marine diatoms Thalassiosira pseudonana and Skeletonema marinoi-dohrnii complex., Chemosphere, 10.1016/j.chemosphere.2017.02.054, 175, 200-209, 2017.06.
21. Ik Joon Kang, Xuchun Qiu,Junya,Moroishi,Yuji Oshima, Sound production in Japanese medaka (Oryzias latipes) and its alteration by exposure to aldicarb and copper sulfate, Chemosphere, 182, 530-535, 2017.04, This study is the first to report sound production in Japanese medaka (Oryzias latipes). Sound production was affected by exposure to the carbamate insecticide (aldicarb) and heavy-metal compound (copper sulfate). Medaka were exposed at four concentrations (aldicarb: 0, 0.25, 0.5, and 1 mg L−1; copper sulfate: 0, 0.5, 1, and 2 mg L−1), and sound characteristics were monitored for 5 h after exposure. We observed constant average interpulse intervals (approx 0.2 s) in all test groups before exposure, and in the control groups throughout the experiment. The average interpulse interval became significantly longer during the recording periods after 50 min of exposure to aldicarb, and reached a length of more than 0.3 s during the recording periods after 120 min exposure. Most medaka fish stopped to produce sound after 50 min of exposure to copper sulfate at 1 and 2 mg L−1, resulting in significantly declined number of sound pulses and pulse groups. Relative shortened interpulse intervals of sound were occasionally observed in medaka fish exposed to 0.5 mg L−1 copper sulfate. These alternations in sound characteristics due to toxicants exposure suggested that they might impair acoustic communication of medaka fish, which may be important for their reproduction and survival. Our results suggested that using acoustic changes of medaka has potential to monitor precipitate water pollutions, such as intentional poisoning or accidental leakage of industrial waste..
22. M. Honda, H. Gunjikake, S. Matsui, Y. Shimasaki, Y. Oshima, Effect of repeated exposure to low oxygen on respiratory metabolism and vertical movements in the pen shell Atrina lischkeana., Journal of the Faculty of Agriculture, Kyushu University, 62, 387-392, 2017.01.
23. Kase, Y., Ogiso, S., Ikari, T., Sekiguchi, T., Sasayama, Y., Kitani, Y., Shimasaki, Y., Oshima Y., Kambegawa, A., Tabuchi, Y., Hattpri A., and Suzuki, N, Immunoreactive calcitonin cells in the nervous system of polychaete Perinereis aibuhitensis, Journal of the Faculty of Agriculture, Kyushu University, 62, 381-385, 2017.01.
24. Kun Chen, Yuki Tsutsumi, Shuhei Yoshitake, Xuchun Qiu, Hai Xu, Yasuyuki Hashiguchi, Masato Honda, Kosuke Tashiro, Kei Nakayama, Takeshi Hano, Nobuo Suzuki, Kazuichi Hayakawa, Yohei Shimasaki, Yuji Oshima, Alteration of development and gene expression induced by in ovo-nanoinjection of 3-hydroxybenzo[c]phenanthrene into Japanese medaka (Oryzias latipes) embryos, Aquatic Toxicology, 10.1016/j.aquatox.2016.11.020, 182, 194-204, 2017.01, Benzo[c]phenanthrene (BcP) is a highly toxic polycyclic aromatic hydrocarbon (PAHs) found throughout the environment. In fish, it is metabolized to 3-hydroxybenzo[c]phenanthrene (3-OHBcP). In the present study, we observed the effects of 1 nM 3-OHBcP on the development and gene expression of Japanese medaka (Oryzias latipes) embryos. Embryos were nanoinjected with the chemical after fertilization. Survival, developmental stage, and heart rate of the embryos were observed, and gene expression differences were quantified by messenger RNA sequencing (mRNA-Seq). The exposure to 1 nM 3-OHBcP accelerated the development of medaka embryos on the 1st, 4th, and 6th days post fertilization (dpf), and increased heart rates significantly on the 5th dpf. Physical development differences of exposed medaka embryos were consistent with the gene expression profiles of the mRNA-Seq results for the 3rd dpf, which show that the expression of 780 genes differed significantly between the solvent control and 1 nM 3-OHBcP exposure groups. The obvious expression changes in the exposure group were found for genes involved in organ formation (eye, muscle, heart), energy supply (ATPase and ATP synthase), and stress-response (heat shock protein genes). The acceleration of development and increased heart rate, which were consistent with the changes in mRNA expression, suggested that 3-OHBcP affects the development of medaka embryos. The observation on the developmental stages and heart beat, in ovo-nanoinjection and mRNA-Seq may be efficient tools to evaluate the effects of chemicals on embryos..
25. Dao M. Hai, Xuchun Qiu, Hai Xu, Masato Honda, Mitsuyasu Yabe, Kiwao Kadokami, Yohei Shimasaki, Yuji Oshima, Contaminants in Liquid Organic Fertilizers Used for Agriculture in Japan, Bulletin of Environmental Contamination and Toxicology, 10.1007/s00128-017-2081-y, 99, 1, 131-137, 2017.01, To provide an overview of anthropogenic contaminants in liquid organic fertilizers (LOFs), products from four biogas plants in Kyushu, Japan, were analyzed for a wide range of contaminants, including copper, cadmium, tributyltin (TBT), dibutyltin (DBT), perfluorooctane sulfonate, 952 semi-volatile organic compounds, and 89 antibiotics. The highest concentrations of copper (31.1 mg/L) and cadmium (0.08 mg/L) were found in LOFs from the Hita biogas plant. Only ofloxacin and sulfapyridine were detected in total 89 antibiotics screened. TBT, DBT, and perfluorooctane sulfonate were present at low concentrations in the LOFs from all four locations. Among the 952 semi-volatile organic compounds, 78 compounds were detected in at least one sample and were present at concentrations between 1.2 and 139.6 mg/L. On the basis of comparisons with previous studies and quality standards for the use of organic fertilizers, the concentrations of contaminants in the studied LOFs indicate that they might be safe for agricultural purposes..
26. Xuchun Qiu, Suzanne Lydia Undap, Masato Honda, Toshio Sekiguchi, Nobuo Suzuki, Yohei Shimasaki, Hironori Ando, Waka Sato-Okoshi, Toshihiro Wada, Tomoki Sunobe, Satoshi Takeda, Hiroyuki Munehara, Hisashi Yokoyama, Noriyuki Momoshima, Yuji Oshima, Pollution of radiocesium and radiosilver in wharf roach (Ligia sp.) by the Fukushima Dai-ichi Nuclear Power Plant accident, Journal of Radioanalytical and Nuclear Chemistry, 10.1007/s10967-016-4879-1, 311, 1, 121-126, 2017.01, Radionuclide concentrations in wharf roaches inhabiting coastal areas of Honshu, Japan, were investigated in October 2011 and June 2012. Relative high concentrations of 110mAg (2.1–127 Bq kg-wet−1), 134Cs (2.6–61 Bq kg-wet−1), and 137Cs (3.5–92 Bq kg-wet−1) were detected in specimens from the eastern Honshu areas. Significantly lower 137Cs concentrations (0.7–1.6 Bq kg-wet−1) were detected in specimens from western and northern Honshu. The decay-corrected 137Cs concentration was significantly inversely correlated with the distance from the Fukushima Dai-ichi Nuclear Power Plant. Thus, wharf roach may serve as a good bioindicator for monitoring radioactive contamination of its habitats..
27. Xuchun Qiu, Sayaka Nomichi, Kun Chen, Masato Honda, Ik Joon Kang, Yohei Shimasaki, Yuji Oshima, Short-term and persistent impacts on behaviors related to locomotion, anxiety, and startle responses of Japanese medaka (Oryzias latipes) induced by acute, sublethal exposure to chlorpyrifos, Aquatic Toxicology, 10.1016/j.aquatox.2017.09.012, 192, 148-154, 2017.01, Although most exposures to chlorpyrifos (CPF) in natural flowing waters are brief and episodic, there have been a few reports of the persistence of abnormal fish behaviors caused by such acute exposure. The present study focused on the behavioral and biochemical responses of Japanese medaka (Oryzias latipes) to acute, sublethal exposure to CPF, as well as the persistence of the effects during a 3-week recovery test in CPF-free water. The medaka became hyperactive and exhibited an elevated anxiety state after a 4-day exposure to 0.024 mg/L of CPF, but they recovered from these abnormal behavioral responses within 7 days of recovery treatment. In contrast, persistent impacts on some startle responses to a sudden stimulation (induced by a ball drop) were observed in medaka exposed to CPF. The reaction latency did not change immediately after the 4-day exposure, but was significantly prolonged by as much as 21 days after the termination of exposure. The post-stimulus swimming distance within 5 s significantly decreased on the day immediately after the 4-day exposure, but it significantly increased after 7 days of recovery treatment. The activity of acetylcholinesterase (AChE) in the brains of medaka was significantly inhibited on the day immediately after the 4-day exposure, but it returned to 80% and 110% of that in control fish on days 7 and 21 of the recovery period, respectively. However, AChE activities in the eyes of exposed medaka were persistently inhibited and declined to 33%, 71%, and 72% of that in control fish on days 0 (immediately after the 4-day exposure), 7, and 21 of recovery, respectively. Correlation analysis suggested that the changes of AChE activities in the brains of medaka may underlie some of the observed acute behavioral changes, and the changes of AChE activities in the eyes may contribute to the persistence of the abnormalities in the reaction latency of the startle response. Our findings suggest that medaka need a long time to recover from acute, sublethal exposure to CPF, and the persistence of the behavioral abnormalities might affect their fitness in natural habitats..
28. Hina Satone, Shohei Nonaka, Jae Man Lee, Yohei Shimasaki, Takahiro Kusakabe, Shun ichiro Kawabata, Yuji Oshima, Tetrodotoxin- and tributyltin-binding abilities of recombinant pufferfish saxitoxin and tetrodotoxin binding proteins of Takifugu rubripes, Toxicon, 10.1016/j.toxicon.2016.11.245, 125, 50-52, 2017.01, We investigated the ability of recombinant pufferfish saxitoxin and tetrodotoxin binding protein types 1 and 2 of Takifugu rubripes (rTrub.PSTBP1 and rTrub.PSTBP2) to bind to tetrodotoxin (TTX) and tributyltin. Both rTrub.PSTBPs bound to tributyltin in an ultrafiltration binding assay but lost this ability on heat denaturation. In contrast, only rTrub.PSTBP2 bound to TTX even heat denaturation. This result suggests that the amino acid sequence of PSTBP2 may be contributed for its affinity for TTX..
29. Hongbo Liu, Xiubao Chen, Yanping Su, Ikjoon Kang, Xuchun Qiu, Yohei Shimasaki, Yuji Oshima, Jian Yang, Effects of Calcium and Magnesium Ions on Acute Copper Toxicity to Glochidia and Early Juveniles of the Chinese Pond Mussel Anodonta woodiana, Bulletin of Environmental Contamination and Toxicology, 10.1007/s00128-016-1890-8, 97, 4, 504-509, 2016.10, We evaluated the effects of calcium (Ca2+) and magnesium (Mg2+) ions on copper (Cu) toxicity to glochidia and newly-transformed juvenile mussels (age 1–2 days) of the Chinese pond mussel (Anodonta woodiana). Acute Cu toxicity tests were performed with glochidia for 24 h and juveniles for 96 h with measured Ca2+ concentrations of 1.1, 14, 26, 51, and 99 mg L−1, or measured Mg2+ concentrations of 2.6, 11, 21, and 39 mg L−1. The Ca2+ and Mg2+ cations provided no statistically significant protection against Cu toxicity to glochidia or juveniles. The 24-h EC50 value for glochidia was 82 μg L−1 Cu, and contrastly, 96-h EC50 value for newly-transformed juvenile mussels was as low as 12 μg L−1 Cu, implying that the juveniles of A. woodiana are more vulnerable to Cu contamination at concentrations close to currently-accepted levels..
30. Xuchun Qiu, Kouki Mukai, Yohei Shimasaki, Michito Tsuyama, Tadashi Matsubara, Yu Nakajima, Tsuneo Honjo, Yuji Oshima, Potential maximum quantum yield of photosystem II reflects the growth rate of Chattonella marina in field bloom samples, Journal of the Faculty of Agriculture, Kyushu University, 61, 2, 331-335, 2016.09, Time series variations in the potential maximum quantum yield of photosystem II (Fv/Fm ratio) and growth rate of field Chattonella marina cells were investigated during a HAB occurred in the inner part of Ariake Sea, Japan (5-14 September, 2012). This study aimed at investigating the usability of Fv/Fm ratio in evaluating the growth of C. marina and its HAB dynamic under natural conditions, by analyzing its correlations with algal growth rate and various environmental variables. Field observation showed that exhaustion of dissolved inorganic nitrogen (DIN) was likely responsible for controlling the growth of C. marina cells and finally induced the bloom termination. As the bloom progressed, both the Fv/Fm ratio (0.62 to 0.72) and growth rate (-0.25 to 0.81 div. d-1) of C. marina cells tended to decrease, and there was a significant positive correlation between the two parameters. Both the Fv/Fm ratio and growth rate of C. marina cells were positively correlated with DIN concentrations, which also supported the inference that DIN was responsible for controlling the dynamics C. marina HAB. Thus, our results suggest that the Fv/Fm ratio, combined with information about environmental factors, may be useful in evaluating the nutrient status and growth potential of C. marina during field blooms..
31. Nobuo Suzuki, Masayuki Sato, Hossam F. Nassar, Fagr Kh Abdel-Gawad, Samah M. Bassem, Koji Yachiguchi, Yoshiaki Tabuchi, Masato Endo, Toshio Sekiguchi, Makoto Urata, Atsuhiko Hattori, Hiroyuki Mishima, Youhei Shimasaki, Yuji Oshima, Chun Sang Hong, Fumiya Makino, Ning Tang, Akira Toriba, Kazuichi Hayakawa, Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish, Carassius auratus, Zoological science, 10.2108/zs150211, 33, 4, 407-413, 2016.08, We have developed an original in vitro bioassay using teleost scale, that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from two sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We were able to detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added to culture medium at dilution rates of 50, 100, and 500, and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, but TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-κB ligand) decreased significantly, as did the ALP enzyme activity. In fact, ALP activity decreased on treatment with PAHs and NPAHs. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influences bone metabolism in teleosts..
32. Liu, H., Chen, X., Su, Y., Qiu, X., Kang., IJ., Shimasaki, Y., Oshima Y., Yang, J. , Effects of Calcium and Magnesium Ions on Acute Copper Toxicity to Glochidia and Early Juveniles of the Chinese Pond Mussel Anodonta woodiana. , Bull of Env Cont Toxi., 97, 504-509, 2016.06.
33. Suzuki, N., Sato, M., Nassar, F. H., Abdel-gawad, F. Kh., Bassem, S.M., Yachiguchi, K., Tabuchi, Y., Endo, M., Sekiguchi, T., Urata, M., Hattori, A., Mishima, H., Shimasaki, Y., Oshima, Y., Hong, C.-S., Makino, F., Tang, N., Toriba, A. and Hayakawa, K.:, Seawater polluted with highly concentrated polycyclic aromatic hydrocarbons suppresses osteoblastic activity in the scales of goldfish, Carassius auratus. , Zool. Sci., 33, 407-413, 2016.06.
34. Qiu, X., Undap, S.L., Honda, M., Sekiguchi, T., Suzuki, N., Shimasaki, Y., Ando, H., Sato-Okoshi, W., Wada, T., Sunobe, T., Takeda, S., Munehara, H., Yokoyama H., Momoshima, N. and Oshima, Y., Pollution of radiocesium and radiosilver in wharf roach (Ligia sp.) by the Fukushima Dai-ichi Nuclear Power Plant accident., J Radioanal Nucl Chem., 311, 121-126, 2016.06.
35. Liu Hongbo, Chen Xiubao, Shimasaki Yohei, Kang Ik Joon, Oshima Yuji, Yang Jian , The valve movement response of three freshwater mussels Corbicula fluminea Müller 1774, Hyriopsis   cumingii Lea 1852, and Anodonta woodiana Lea 1834 exposed to copper. , Hydrobiologia, 270, 1-13, 2016.06.
36. Qiu, X., Mukai, K., Shimasaki, Y., Tsuyama, M., Matsubara, T., Nakajima, Y., ... Oshima, Y., Potential Maximum Quantum Yield of Photosystem II Reflects the Growth Rate of Chattonella marina in Field Bloom Samples., Journal of the Faculty of Agriculture, Kyushu University,, 61, 331-335, 2016.06.
37. Wilmy Etwil Pelle, Masashi Kamo, Takehiko I. Hayashi, Takeshi Kimura, Yohei Shimasaki, Yuji Oshima, Biotic ligand model of copper toxicity to Japanese medaka (Oryzias latipes) in low-hardness water
, 日本環境毒性学会, 18, 2, 59-71, 2015.12.
38. Liu Hongbo, Chen Xiubao, Yohei Shimasaki, Kang Ik Joon, Yamasaki Y, Yuji Oshima, Yang Jian, The valve movement response of three freshwater mussels Corbicula fluminea Müller 1774, Hyriopsis cumingii Lea 1852, and Anodonta woodiana Lea 1834 exposed to copper .
, Hydrobiologia, 10.1007/s10750-015-2560-2, 1-13, 2015.10.
39. Nobuo Suzuki, Somei, M, Atsuhiko HATTORI, Seki, A, Sekiguchi, T, Tabuchi, Y, Mishima, H, Kase, Y, Kaminishi, A, Yachiguchi, K, Kitamura, K, Yuji Oshima, Kazuichi HAYAKAWA, Yano, S, Hattori, A, Novel tryptophan derivatives as potentially effective therapeutic drugs to treat bone diseases., J. Life Sci., in press, in press, 2015.06, Suzuki, N., Somei, M., Seki, A., Sekiguchi, T., Tabuchi, Y., Mishima, H., Kase, Y., Kaminishi, A., Yachiguchi, K., Kitamura, K., Oshima, Y., Hayakawa, K., Yano, S. and Hattori, A.: Am. .
40. Hashiguchi Y, JAE MAN LEE, Shiraishi M, Komatsu S, Miki S, Yohei Shimasaki, Noritaka Mochioka, takahiro kusakabe, Yuji Oshima, Hayakawa, K, Characterization and evolutionary analysis of tributyltin-binding protein (TBT-bp) and pufferfish saxitoxin and tetrodotoxin binding protein (PSTBP) genes in toxic and non-toxic pufferfishes. , J Evol Biol. , doi: 10.1111/jeb.12634. , 2015.06, , Lee JM, Shiraishi M, Komatsu S, Miki S, Shimasaki Y, Mochioka N, Kusakabe T, Oshima Y. .
41. Yohei Shimasaki, Michito Tsuyama, Rumana Tasmin, Mst Ruhina Margia Khanam, Xuchun Qiu, Yuji Oshima, Comparative study of toxicological responses of chlorophyll-related parameters in the marine diatom Skeletonema sp. exposed to tributyltin and Irgarol. Jpn., Jpn. J. Environ. Toxicol., 18, 2015.06, Yohei Shimasaki, Michito Tsuyama, Rumana Tasmin, Mst Ruhina Margia Khanam, Xuchun Qiu, Yuji Oshima .
42. Nobuo Suzuki, Shouzo Ogiso, Koji Yachiguchi, Kimi Kawabe, Fumiya Makino, Akira Toriba, Masato Kiyomoto, oshio Sekiguchi, Yoshiaki Tabuchi, Takashi Kondo, Kei-ichiro Kitamura, Chun-Sang Hong, Ajai K Srivastav,, Yuji Oshima, Atsuhiko Hattori, Kazuichi Hayakawa, Monohydroxylated polycyclic aromatic hydrocarbons influence spicule formation in the early development of sea urchins (Hemicentrotus pulcherrimus), Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, 10.1016/j.cbpc.2015.02.004, 171, 55-60, 2015.05, We previously demonstrated that monohydroxylated polycyclic aromatic
hydrocarbons (OHPAHs), which are metabolites of polycyclic aromatic hydrocarbons
(PAHs), act on calcified tissue and suppress osteoblastic and osteoclastic activity in the
scales of teleost fish. The compounds may possibly influence other calcified tissues. Thus,
the present study noted the calcified spicules in sea urchins and examined the effect of both
PAHs and OHPAHs on spicule formation during the embryogenesis of sea urchins..
43. Y. Hashiguchi, Man Lee, M. Shiraishi, S. Komatsu, S. Miki, Yohei Shimasaki, Noritaka Mochioka, Takahiro Kusakabe, Yuji Oshima, Characterization and evolutionary analysis of tributyltin-binding protein and pufferfish saxitoxin and tetrodotoxin-binding protein genes in toxic and nontoxic pufferfishes, Journal of Evolutionary Biology, 10.1111/jeb.12634, 28, 5, 1103-1118, 2015.05, Understanding the evolutionary mechanisms of toxin accumulation in pufferfishes has been long-standing problem in toxicology and evolutionary biology. Pufferfish saxitoxin and tetrodotoxin-binding protein (PSTBP) is involved in the transport and accumulation of tetrodotoxin and is one of the most intriguing proteins related to the toxicity of pufferfishes. PSTBPs are fusion proteins consisting of two tandem repeated tributyltin-binding protein type 2 (TBT-bp2) domains. In this study, we examined the evolutionary dynamics of TBT-bp2 and PSTBP genes to understand the evolution of toxin accumulation in pufferfishes. Database searches and/or PCR-based cDNA cloning in nine pufferfish species (6 toxic and 3 nontoxic) revealed that all species possessed one or more TBT-bp2 genes, but PSTBP genes were found only in 5 toxic species belonging to genus Takifugu. These toxic Takifugu species possessed two or three copies of PSTBP genes. Phylogenetic analysis of TBT-bp2 and PSTBP genes suggested that PSTBPs evolved in the common ancestor of Takifugu species by repeated duplications and fusions of TBT-bp2 genes. In addition, a detailed comparison of Takifugu TBT-bp2 and PSTBP gene sequences detected a signature of positive selection under the pressure of gene conversion. The complicated evolutionary dynamics of TBT-bp2 and PSTBP genes may reflect the diversity of toxicity in pufferfishes..
44. Xuchun Qiu, Yohei Shimasaki, Yukifumi Yoshida, Tadashi Matsubara, Yasuhiro Yamasaki, Mayumi Kawaguchi, Masato Honda, Kentaro Mouri, Yu Nakajima, Rumana Tasmin, Katsutoshi Kuno, Yoshio Kawamura, Tsuneo Honjo, Yuji Oshima, Allelopathic effects of Skeletonema spp. may influence interspecific competition and bloom formation of co-occurring harmful flagellates, Journal of the Faculty of Agriculture, Kyushu University, 59, 2, 373-382, 2014.08, We investigated the allelopathic effects of Skeletonema spp. on growth and interspecific competition of the co-occurring flagellates Akashiwo sanguinea, Chattonella spp., and Heterosigma akashiwo, by reviewing field data on fluctuations in their cell densities and through laboratory experiments. From 29 June to 3 September, 2007, three dense blooms were observed in the inner part of the Ariake Sea, Japan. In all the 4 stations, Skeletonema spp. were generally detected and contributed to blooms from 20 to 23 July and from 6 to 13 August. Chattonella spp. gradually grew from mid-July and formed mixed blooms with Skeletonema spp. from 6 to 13 August, and then caused an almost mono-specific bloom in the station 2 and 3 from 20 to 24 August. However, H. akashiwo and A. sanguinea generally maintained low cell densities. Laboratory experiments showed that when grown in re-enriched culture filtrates of Skeletonema sp. (NIES-324) and cultured with Skeletonema sp. under non-contact conditions, A sanguinea suffered the highest growth inhibitory effect, followed by H. akashiwo, while C. antiqua was the most resistant species. In tri-algal culture of these flagellates, the allelopathic effects of Skeletonema sp. increased the proportion of C. antiqua cells and decreased those of H. akashiwo and A. sanguinea, perhaps giving C. antiqua a competitive advantage over the other 2 flagellates. Our results suggest that allelopathy of Skeletonema spp. has potential to influence interspecific competition of these flagellates owing to species-specific growth inhibitory levels, and sometimes may be propitious to bloom formation of Chattonella spp. in the field..
45. Rumana Tasmin, Yohei Shimasaki, Michito Tsuyama, Xuchun Qiu, Khalil F, Okino N, Naotaka Yamada,, Shinji FUKUDA, Yuji Oshima, Kang IJ, Elevated water temperature reduces the acute toxicity of the widely used herbicide diuron to a green alga, Pseudokirchneriella subcapitata. , Environ Sci Poll Res, 21, 1070, 2014.06, Tasmin R, Shimasaki Y, Tsuyama M, Qiu X, Khalil F, Okino N, Yamada N, Fukuda S, Kang IJ, Oshima Y. .
46. Rumana Tasmin, Yohei Shimasaki, Yoshida Y, Matsubara T, Yamasaki Y, Kawaguchi M, Honda M, Mouri K, Nakajima Y, Tasmin R, Kuno K, Kawamura Y, Yuji Oshima, Allelopathic effects of Skeletonema spp. may influence interspecific competition and bloom formation of co-occurring harmful flagellates., Journal of the Faculty of Agriculture, Kyushu University. , 59, 382, 2014.06, Allelopathic effects of Skeletonema spp. may influence interspecific competition and bloom formation of co-occurring harmful flagellates. .
47. Masato Honda, Akemi Muta, Taiki Akasaka, Yoshiyuki Inoue, Yohei Shimasaki, Kurunthachalam Kannan, Nozomu Okino, Yuji Oshima, Identification of perfluorooctane sulfonate binding protein in the plasma of tiger pufferfish Takifugu rubripes, Ecotoxicology and Environmental Safety, 10.1016/j.ecoenv.2013.11.010, 104, 1, 409-413, 2014.06, It is well known that perfluorooctane sulfonate (PFOS) preferentially accumulates in the plasma of wildlife and humans. Although earlier studies have suggested that this was due to binding of PFOS to a plasma protein, definite characterization of the protein in in vivo exposure studies was not conducted thus far. In this study, we conducted both in vitro and in vivo experiments to identify PFOS binding protein in the plasma of fish. For the in vivo studies, PFOS was administered intraperitoneally to tiger pufferfish, Takifugu rubripes, and the plasma was separated by ammonium sulfate fractionation. High concentrations of PFOS were found in the 65-70 percent ammonium sulfate fraction (190. ng/mL). After SDS-PAGE and N-terminal amino acid sequence analysis, the PFOS-binding protein was identified as an apolipoprotein A-I, which was confirmed on the basis of a significant correlation to the PFOS concentration in each fraction. The plasma samples fractionated by ammonium sulfate from untreated pufferfish were subjected to PFOS binding assay by the equilibrium dialysis method. The results further confirmed that the 60-65 percent ammonium sulfate fraction showed a high PFOS-binding ratio, similar to that found from in vivo studies. We demonstrated that PFOS is likely bound to an apolipoprotein A-I in the plasma of tiger pufferfish in in vivo and in vitro studies..
48. Suzanne Lydia, Masato HONDA, Yohei Shimasaki, Rizald Max ROMPAS, Noritaka Mochioka, Yuji Oshima, Monitoring of Tributyltin Contamination of Demersal Fish in Coastal Water in East China Sea J. Fac. Agr, Kyu. Univ. Vol. 59: 103-107. 2014, J. Fac. Agr, Kyu. Univ. , 59, 103-107, 2014.02.
49. Nobuo Suzuki, Yusuke MARUYAMA, Masaki NAKANO, Atsuhiko HATTORI, Masato Honda, Toshio Skiguchi, Hiroyuki MISHIMA, Shigehito WADA, Ajai K. SRIVASTAV, Kazuichi HAYAKAWA, 大嶋 雄治, Increased PGE2 Has a Positive Correlation with Plasma Calcium during Goldfish Reproduction.
, J. Fac. Agr, Kyu. Univ., 59, 97-101, 2014.02.
50. Rumana Tasmin, Yohei Shimasaki, Xuchun Qiu, Masato Honda, Michito Tsuyama, Naotaka Yamada,, Shinji FUKUDA, Yuji Oshima, Elevated temperatures and low nutrients decrease the toxicity of diuron for growth of the green alga Pseudokirchneriella subcapitata. , J J Env Tox , 17, 5-10, 2014.02.
51. Nobuo Suzuki, Yusuke Maruyama, Masaki Nakano, Atsuhiko Hattori, Masato Honda, Yohei Shimasaki, Toshio Sekiguchi, Hiroyuki Mishima, Shigehito Wada, Ajai K. Srivastav, Kazuichi Hayakawa, Yuji Oshima, Increased prostaglandin e2 has a positive correlation with plasma calcium during goldfish reproduction, Journal of the Faculty of Agriculture, Kyushu University, 59, 1, 97-101, 2014.02, We recently demonstrated that prostaglandin E2 PG¿ increases osteoclastic activity and induces bone resorption in both in vitro and in vivo experiments using goldfish. In the fish reproductive period, the plasma calcium (Ca) level in female teleosts increases remarkably to make vitellogenin, which is a major component of egg protein and a Ca-binding protein. In this period, however, there is no reported relationship between PGE2 and Ca metabolism in fish. To clarify the Ca metabolism in fish reproduction, we examined plasma PGE2 and Ca levels and measured tartrate-resistant acid phosphatase (TRAP) activities as an indicator of osteoclastic activity in goldfish. Plasma PGE2 levels in the reproductive stage significantly increased as compared with those in non-reproductive stages. Also, both plasma Ca and TRAP increased in the reproductive stage. Significant positive correlations were recognized between plasma Ca and the gonad somatic index (r=0.81, p<0.001), plasma Ca and plasma PGE2 levels (r=0.635, p<0.05), and plasma Ca and plasma TRAP activities (r=0.584, p<0.05) from the analysis using samples of both reproductive and nonreproductive stages. Taking these data into consideration, we suggested that PGE, acts on osteoclasts and increases plasma Ca as a result of osteoclastic bone resorption, and we concluded that PGE, is an important hormone in Ca metabolism during fish reproduction..
52. Suzanne Lydia Undap, Masato Honda, Natalie D. Rumampuk, Suguru Inoue, Yohei Shimasaki, Rizald Max Rompas, Noritaka Mochioka, Yuji Oshima, Monitoring of tributyltin contamination of demersal fish in coastal water in East China Sea, Journal of the Faculty of Agriculture, Kyushu University, 59, 1, 103-107, 2014.02, To monitor the pollution of tributyltin (TBT) in East China Sea, five species of fish (Sphoeroides pachygaster, Dentex tumifrons, Chelidonichthys kumu, Niphon spinosus and Monocentris japonica) and two crustacean species (Charybdis miles and Ibacus ciliatus) were collected from the East China Sea on 2010. In addition, common Japanese conger (Conger myriaster) was collected from the East China Sea and Hakata Bay from June 2009 to September 2011. Aquaculture fish (Paralichthys olivaceos, Pargus major, and Trachurus japonicus) were also collected from a fish market in Fukuoka, Japan on March 10, 2010. As results, no TBT or its metabolite (dibutyltin, DBT) were detected in the blood, liver and muscle of the five species of fish, the midgut gland of the two crustaceans or the livers of conger eels collected from the East China Sea(<0.0005μg/mL or μg/g). However, TBT (0.002-0.04 μg/g) and DBT (0.008-0.06 μg/g) were detected in the livers of common Japanese conger collected from Hakata Bay. Moreover, TBT was detected in the blood of three species of cultured fish obtained from the fish market in Fukuoka at levels ranging from no detected <0.0005 μg/mL-0.21μ/mL. These results suggest that no TBT contamination occurred in the East China Sea, while common Japanese conger from Hakata Bay and cultured fish were still contaminated by TBT..
53. Rumana Tasmin, 島崎 洋平, 津山 孝人, Fatma Khalil, 沖野 望, Naotaka Yamada, 福田 信二, k-Joon Kang, 大嶋 雄治, Elevated water temperature reduces the acute toxicity of the widely used herbicide diuron to a green alga, Pseudokirchneriella subcapitata, ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH, 10.1007/s11356-013-1989-y, 21, 2, 1064-1070, 2014.01.
54. Tao Jiang, Hongbo Liu, Xinqiang Shen, Yohei Shimasaki, Yuji Oshima, Jian Yang, Life history variations among different populations of Coilia nasus along the Chinese coast inferred from otolith microchemistry, Journal of the Faculty of Agriculture, Kyushu University, 59, 2, 383-389, 2014.01, The habitat use and the migratory patterns of different estuarine tapertail anchovy Coilia nasus populations along the Chinese coast were studied by examining the environmental signatures of strontium and calcium in their otoliths using electron probe microanalysis (EPMA). The results showed that the life patterns were quite similar between the individuals from the Huanghe (Yellow) River and Changjiang (Yangtze) River and considerably different from those of the Qiantang River and Oujiang River. Most of the anchovies were typical anadromous fish, but several individuals were brackish-water residents. Our results also suggest that C. nasus may probably be a natal homing fish..
55. Hina Satone, Eriko Akahoshi, Aiko Nakamura, Jae Man Lee, Masato Honda, Yohei Shimasaki, Shun ichiro Kawabata, Takahiro Kusakabe, Yuji Oshima, Expression and functional characterization of recombinant tributyltin-binding protein type 2, Journal of Toxicological Sciences, 10.2131/jts.38.885, 38, 6, 885-890, 2013.11, Tributyltin-binding proteins (TBT-bps) are members of the fish lipocalins that were isolated from the blood of Japanese flounder (Paralichthys olivaceus) and function in the binding and detoxification of TBT. In this study, we constructed a baculovirus-silkworm expression system and obtained recombinant TBT-bp2 (rTBT-bp2; 31.5 kDa) from the hemolymph of silkworm larvae injected with a recombinant baculovirus containing the TBT-bp2 gene. The binding potential of rTBT-bp2 was investigated and compared to that of the previously available recombinant TBT-bp1 (rTBT-bp1). Both rTBT-bp2 and rTBT-bpl bound to DAUDA, a typical fluorescent ligand of lipocalins, with dissociation constants of 0.97 and 1.75 μM, respectively. The Hill coefficient value indicated that rTBT-bp2 may have multiple binding sites and strong negative cooperativity. These results suggest that the typical central cavity of lipocalins composed of eight specific P-sheets is conserved in rTBT-bp2, as it is in rTBT-bpl, although rTBT-bp2 has different effects than rTBT-bp1 in TBT binding. In a competition assay, rTBT-bp2 displayed exponential binding affinity to TBT with an inhibition constant of 0.29 μM, demonstrating that TBT binds to the central ligand pocket of rTBT-bp2. However, three fatty acids did not show any affinity to rTBT-bp2. Further studies are required to elucidate the endogenous function of TBT-bps as fish lipoca-lins and their function in responding to xenobiotics..
56. Suzanne L Undap, Satoshi Matsunaga, Masato Honda, Toshio Skiguchi,, Nobuo Suzuki,, Fatma Khalil, Xuchun Qiu, 島崎 洋平, Hironori Ando, Waka Sato-Okoshi, Tomoki Sunobe, Satoshi Takeda, Hiroyuki Munehara, 大嶋 雄治, Accumulation of organotins in wharf roach (Ligia exotica Roux) and its ability to serve as a biomonitoring species for coastal pollution, ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, 10.1016/j.ecoenv.2013.06.019, 96, 75-79, 2013.10.
57. Suzanne L Undap, Masato Honda, Natalie D. RUMAMPUK, Suguru INOUE, 島崎 洋平, Rizald Max ROMPAS, 望岡 典隆, 大嶋 雄治, Monitoring of Tributyltin Contamination of Demersal Fish in Coastal Water in East China Sea , J. Fac. Agr, Kyu. Univ. , 59, 103-107, 2013.10.
58. 島崎 洋平, 津山 孝人, Rumana Tasmin, Xuchun Qiu, Motoyuki Shimizu, Yusuke Sato, Yasuhiro Yamasaki,, Yoko Kato-Unoki, Atsushi Nukata, Hirofumi Ichinose, Hiroyuki Wariishi, Tsuneo Honjo, 大嶋 雄治, Thiobencarb Herbicide Reduces Growth, Photosynthetic Activity, and Amount of Rieske Iron-Sulfur Protein in the Diatom Thalassiosira pseudonana, JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, 10.1002/jbt.21505, 27, 9, 437-444, 2013.09.
59. Dong Myung Kim, Sunyoung Kim, Jiwon Suk, Yong Hyun Chung, Young Mog Kim, Kyong Joon Roh, Seok Jin Oh, Yuji Oshima, Ik Joon Kang, A Study on the distribution of nonylphenol in estuaries in busan, Korea, Journal of the Faculty of Agriculture, Kyushu University, 58, 2, 313-318, 2013.09, Nonylphenol (NP) is known as one of Endocrine Disrupting Chemicals (EDCs) is the degradation product of Nonylphenol ethoxylates (NPEs) being used as nonionic surfactant. NP is classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. In order to understand the behavior of NP in urban stream, this study was examined occurrence of NP in estuary of Nakdong River and Suyoung River. Water sampling for a raining season was performed in July 2011 and about the dry season was conducted in October 2011. During the survey period, the range of NP concentration in estuary of the Nakdong River was 137.1∼10,931.5 ng/L and the average was 2,315.1 ng/L. Surface water of estuary of Suyoung River had the range of 144.0∼2,469.6 ng/L and the average of 712.0 ng/L. It was found that NP concentration of Suyoung River and Nakdong River was similar or lower compared to results of studies in Korea and other countries..
60. Dong Myung Kim, Sunyoung Kim, Jiwon Suk, Yong Hyun Chung, Young Mog Kim, Kyong Joon Roh, Seok Jin Oh, Yuji Oshima, Ikjoon Kang, A Study on the distribution of nonylphenol in estuaries in busan, Korea, Journal of the Faculty of Agriculture, Kyushu University, 58, 2, 313-318, 2013.09, Nonylphenol (NP) is known as one of Endocrine Disrupting Chemicals (EDCs) is the degradation product of Nonylphenol ethoxylates (NPEs) being used as nonionic surfactant. NP is classified as an endocrine disrupter capable of interfering with the hormonal system of numerous organisms. In order to understand the behavior of NP in urban stream, this study was examined occurrence of NP in estuary of Nakdong River and Suyoung River. Water sampling for a raining season was performed in July 2011 and about the dry season was conducted in October 2011. During the survey period, the range of NP concentration in estuary of the Nakdong River was 137.1∼10,931.5 ng/L and the average was 2,315.1 ng/L. Surface water of estuary of Suyoung River had the range of 144.0∼2,469.6 ng/L and the average of 712.0 ng/L. It was found that NP concentration of Suyoung River and Nakdong River was similar or lower compared to results of studies in Korea and other countries..
61. Hyeong Kyu Kwon, Seok Jin Oh, Han Soeb Yang, Dong Myung Kim, Ikjoon Kang, Yuji Oshima, Laboratory Study for the Phytoremediation of Eutrophic Coastal Sediment Using Benthic Microalgae and Light Emitting Diode (LED), Journal of the Faculty of Agriculture, Kyushu University, 58, 2, 417-425, 2013.09, We investigated the effects of three wavelengths of light (blue; 450 nm, yellow, 590 nm and red; 650 nm) using light emitting diodes (LEDs) on the growth of benthic microalgae (BMA) Achnanthes sp., Amphora sp., Navicula sp., Nitzschia sp. and the harmful algae Alexandrium tamarense. In addition, we confirmed phytoremediation possibilities of eutrophic coastal sediments obtain from Masan Bay in 60 L water tank with LEDs. The growth rates of four BMA species could grow under all irradiance conditions of three wavelengths. However, the growth rate of A. tamarense was stimulated under blue LED and suppressed under yellow and red LED to less than 70μmol/m2/s. In water tank experiments with no light, environmental factors, such as cell density of Nitzschia sp., chlorophyll a (ChI. a), chemical oxygen demand (COD), acid volatile sulfide (AVS), dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), were no significant increases or decreases. However, in water tank experiments with LED, cell density Nitzschia sp. and chl. a increased, whereas DIN, DIP, and AVS levels decreased. The removal efficiencies for DIN, DIP, and AVS were high in the order of blue LED, fluorescent lamp, red LED, and yellow LED. Thus, in order to remediate eutrophic sediments, red LED may be the most appropriate during the spring and summer when appearances of harmful algae in the genus Alexandrium are present and blue LED may be the most appropriate during other seasons. benthic microalgae,..
62. Masato Honda, Akemi Muta, Taiki Akasaka, Yoshiyuki Inoue, 島崎 洋平, Kurunthachalam Kannan, 沖野 望, 大嶋 雄治, Identification of perfluorooctane sulfonate binding protein in the plasma of tiger pufferfish Takifugu rubripes, Ecotox. Environ. Saf. , 104, 409-413, 2013.07.
63. Yudai Nagata, Jae Man Lee, Hiroaki Mon, Shigeo Imanishi, Sun Mee Hong, Shoji Komatsu, Yuji Oshima, Takahiro Kusakabe, RNAi suppression of β-N-acetylglucosaminidase (BmFDL) for complex-type N-linked glycan synthesis in cultured silkworm cells, Biotechnology letters, 10.1007/s10529-013-1183-9, 35, 7, 1009-1016, 2013.07, Glycoproteins have various biological functions including enzymatic activity, protein stability and others. Due to the presence of paucimannosidic N-linked glycans, recombinant proteins from an insect cell expression system may not be suitable for therapeutic use. Because baculovirus expression systems (BESs) are used to produce recombinant proteins, it is of interest to modify the endogenous N-glycosylation pathway in insects to mimic that of mammals. Using a soaking RNAi sensitive cell line, BmN4-SID1, has enabled us to suppress Bombyx mori FDL (BmFDL), an N-linked glycan-specific β-N-acetylglucosaminidase. Western blotting and MALDI-TOF MS demonstrated that the BmFDL depletion almost completely converted the paucimannosidic structures of the recombinant proteins produced by BES into a complex-type structure. This highly efficient, simple and low-cost method can be used for mass production of secretion proteins with complex-type N-linked glycans..
64. Trang DANG, Masato HONDA, Makoto SHIRAISHI, Xuchun QIU, Takuro HOTTA, Tatsuhiko TSUSAKI, Yukihiko MATSUYAMA, Yohei Shimasaki, Yuji Oshima, Pharmacokinetic study of catechin (epigallocatechin gallate) after intraperitoneal and oral administration to yellowtail Seriola quinqueradiata.
, Aquaculture Science, 61, 2013.06.
65. Fatma Khalil, Ikjoon Kang, Suzanne Undap, Rumana Tasmin, Xuchun Qiu, Yohei Shimasaki, Yuji Oshima, Alterations in social behavior of Japanese medaka (Oryzias latipes) in response to sublethal chlorpyrifos exposure, Chemosphere, 10.1016/j.chemosphere.2013.02.042, 92, 1, 125-130, 2013.06, The behavioral and biochemical responses of Japanese medaka (Oryzias latipes) to acute and subacute (sublethal) levels of chlorpyrifos were studied. In the acute exposure test, medaka were exposed to 0.018, 0.055, 0.166, or 0.500mgL-1 chlorpyrifos for 4d. As a result, fish showed hypoactivity compared to the control (at 0.018, 0.055, and 0.166mgL-1, swimming speeds were 55.6%, 39.0%, and 27.3% those of the control), Brain acetylcholinesterase activity and swimming speed were significantly correlated. In the subacute toxicity test, medaka were exposed to 0.012mgL-1 chlorpyrifos (10% of LC50) for 8d. On day 4, there were no significant differences in behavioral and biochemical endpoints in exposed fish as compared to the control. On day 8, exposed fish became hyperactive, and the swimming speed of the social group increased to 2times that of the control, whereas acetylcholinesterase activity was decreased to 68% that of the control. In addition, fish exhibited significant alterations in social behavior (schooling duration increased to 2.6times and solitary duration decreased to 28% that of the control). Our findings clearly demonstrate a subacute effect of chlorpyrifos on the social behavior of medaka, which may pose a risk at population level because of the disturbance of social behavior. In addition, the recorded behavioral alterations may provide a useful tool for assessing the toxicity of organophosphorous pesticides to aquatic organisms..
66. Suzanne Lydia UNDAP, Yuji Oshima, Shizuho MIKI, Suguru INOUE, Masato HONDA, Yohei Shimasaki, High tributyltin contamination in sediments from ports in Indonesia and northern Kyushu, Japan , Faculty of Agriculture, Kyushu University , 58, 131-135, 2013.03.
67. Fatma Khalil, Ik Joon Kang, Suzanne Undap, Rumana Tasmin, Yohei Shimasaki, Yuji Oshima, Alterations in social behavior of Japanese medaka (Oryzias latipes) in response to sublethal chlorpyrifos exposure. , Chemoshphere, 92, 125-130, 2013.02.
68. Xuchun Qiu, Yohei Shimasaki, Michito Tsuyama, Taku Yamada, Rie Kuwahara, Mayumi Kawaguchi, Masato Honda, Hiroaki Gunjikake, Rumana Tasmin, Motoyuki Shimizu, Yusuke Sato, Yoko Kato-Unoki, Takashi Nakashima, Tadashi Matsubara, Yasuhiro Yamasaki, Hirofumi Ichinose, Hiroyuki Wariishi, Tsuneo Honjo, Yuji Oshima, Growth-phase dependent variation in photosynthetic activity and cellular protein expression profile in the harmful raphidophyte Chattonella antiqua, Bioscience, Biotechnology and Biochemistry, 10.1271/bbb.120543, 77, 1, 46-52, 2013.02, This study investigated temporal variations in the potential maximum quantum yield of photosystem II (Fv/Fm ratio) and growth-phase dependent cellular protein expressions of Chattonella antiqua under laboratory conditions. Despite the culture conditions, significant positive correlations between the Fv/Fm ratio and daily growth rate were observed. Threshold Fv/Fm ratios associated with positive cell growth were calculated to be >0:44, >0:44, and >0:37, and those associated with active cell growth (growth rate >0:5 div. d-1) were >0:58, >0:60, and >0:49 under control culture, low nutrient and intense light conditions, respectively. Proteome profiles obtained by two-dimensional gel electrophoresis (2-DE) indicated that 42 protein spots were differentially expressed at various growth phases of C. antiqua, which indicates changes in cellular physiological status throughout the growth cycle, and suggests that oxygen evolving enhancer 1 and 2-cysteine peroxiredoxin play roles in maintaining the positive growth of C. antiqua..
69. Suzanne Lydia Undap, Kukuh Nirmala, Shizuho Miki, Suguru Inoue, Xuchun Qiu, Masato Honda, Yohei Shimasaki, Yuji Oshima, High tributyltin contamination in sediments from ports in Indonesia and Northern Kyushu, Japan, Journal of the Faculty of Agriculture, Kyushu University, 58, 1, 131-135, 2013.02, Sediment samples were collected from 20 stations in the port areas around three cities (Jakarta, Bali and Manado) in Indonesia in 2011 and from 9 stations in the port areas in northern Kyushu, Japan in 2010. High concentrations of tributyltin (TBT) were found in sediments collected in front of the shipyard in Bitung port, Manado (4.25 &μg/g wet weight) and in Benoa port, Bali (0.21 fig/g wet weight). High TBT concentrations were also detected in sediments from next to the shipyard in Hakata port (0.63fig/g wet weight), Fukuoka, Japan. These results suggest that ports might be major sources of TBT pollution in Indonesia and Japan, even though TBT usage has been regulated in Japan since 1990..
70. X Qiu, T Yamada, R Kuwahara, M Kawaguchi, M Honda,, H Gunjikake, R Tasmin, M Shimizu, Y Sato, Y Kato-Unoki, T Nakashima, T Matsubara, Y Yamasaki, H Ichinose, H Wariishi, T Honjo, Yuji Oshima, Growth-Phase Dependent Variation in Photosynthetic Activity and Cellular Protein Expression Profile in the Harmful Raphidophyte Chattonella antiqua., Bioscience, biotechnology, and biochemistry., 77, 46-52, 2013.01.
71. X Chen,, J Yang, H Liu, Y Su, L Sun, Yuji Oshima, Element Concentrations in a Unionid Mussel (Anodonta woodiana) at Different Life Stages., Faculty of Agriculture, Kyushu University 2012., 57, 139-144, 2012.10.
72. UK Hwang, JS Park, JN Kwon, S Heo, Yuji Oshima, HS Kang, Effect of Nickel on Embryo Development and Expression of Metallothionein Gene in the Sea Urchin (Hemicentrotus pulcherrimus).Faculty of Agriculture, Kyushu University 57:145-149 2012., Faculty of Agriculture, Kyushu University 2012., 57, 145-149, 2012.10.
73. Kyoko Oishi, Saori Koga, Nobuyoshi Fukae, Yuji Oshima, Yohei Shimasaki, Reduction of the cytotoxicity of triphenyltin chloride using cyclodextrins, Environmental Chemistry Letters, 10.1007/s10311-012-0353-7, 10, 3, 281-286, 2012.09, This report shows that cyclodextrins increase by up to 40% the survival of a marine nematode exposed to triphenyltin chloride. Environmental contamination by organotins has induced toxic effects such as endocrine disruption and destruction of the membrane structure of aquatic organisms. However, techniques to reduce organotin toxicity are scarce. Here, we tested α-, β-, and γ-cyclodextrins to reduce toxicity induced by triphenyltin chloride. We analyzed a receptor cofactor ligand assay system in vitro, parallel artificial membrane permeability assay, and the survival of Prochromadorella sp. 1, one of the nematodes which is served as biomarkers for ecotoxicological assessment. The passive transport of triphenyltin chloride through the artificial membrane was suppressed about 20 and 40% by α- and γ-cyclodextrins and β-cyclodextrin, respectively. On the other hand, the transcription activity in vitro by triphenyltin chloride using the receptor cofactor ligand assay system was not suppressed by cyclodextrins. These results show that cyclodextrins do not inhibit directly the transcription activity of triphenyltin chloride but does inhibit the incorporation of triphenyltin chloride into the target cell. The survival ratio of Prochromadorella sp. 1 during 24-h exposure to triphenyltin chloride of 5 × 10 -6 mol/L was about 5%. The additions of α-, β-, and γ-cyclodextrins increased the survival ratio of about 15, 40, and 20%, respectively. Therefore, cyclodextrins, especially β-cyclodextrin, play an important role in reducing the cytotoxicity by inhibiting the incorporation of triphenyltin chloride into the target cell. Cyclodextrins use in food and pharmaceutical industries can also be applied for the reduction of the toxicities of chemical contaminants..
74. Xuchun Qiu, Yasuhiro Yamasaki, Yohei Shimasaki, Hiroaki Gunjikake, Masato Honda, Mayumi Kawaguchi, Tadashi Matsubara, Sou Nagasoe, Takuya Etoh, Shigeaki Matsui, Tsuneo Honjo, Yuji Oshima, Allelopathy of the raphidophyte Heterosigma akashiwo against the dinoflagellate Akashiwo sanguinea is mediated via allelochemicals and cell contact, Marine Ecology Progress Series, 10.3354/meps09476, 446, 107-118, 2012.02, Growth interactions between the raphidophyte Heterosigma akashiwo and the dinoflagellate Akashiwo sanguinea were examined by using bi-algal culture experiments under axenic conditions. There was a lethal effect of H. akashiwo (initial cell density: 1 × 10 2 or 1 × 10 4 cells ml -1) on A. sanguinea at an initial cell density of 1 × 10 2 cells ml -1. Growth of both species was suppressed concurrently when initial cell densities of H. akashiwo and A. sanguinea were 1 × 10 2 and 2 × 10 3 cells ml -1, respectively. A mathematical model was used to simulate growth and interactions in bi-algal cultures. The model predicted that H. akashiwo would outcompete A. sanguinea over time. A cell-free enriched filtrate prepared from dense culture of H. akashiwo reduced both maximum growth rate and maximum yield of A. sanguinea. A filtrate of A. sanguinea prepared in the same manner only reduced maximum yield of H. akashiwo but did not affect its maximum growth rate. Growth of A. sanguinea in bi-algal cultures under contact conditions was significantly lower than that in mono-algal culture and in bi-algal cultures under noncontact conditions. Morphologically abnormal A. sanguinea cells occurred at high frequency only when A. sanguinea was cultured together with H. akashiwo under direct cell contact condition. Moreover, growth inhibition and formation of morphologically abnormal cells of A. sanguinea were induced in a concentration-dependent manner by allelochemicals (including allelochemical polysaccharide-protein complexes) produced by H. akashiwo. These results suggest that growth inhibition effects, via allelochemicals and direct cell contact by Heterosigma akashiwo, influence bloom formation of Akashiwo sanguinea in the field..
75. Un Ki Hwang, Jong Soo Park, Jung No Kwon, H. E.O. Seung, Yuji Oshima, Han Seung Kang, Effect of nickel on embryo development and expression of metallothionein gene in the sea urchin (hemicentrotus pulcherrimus), Journal of the Faculty of Agriculture, Kyushu University, 57, 1, 145-149, 2012.02, Sea urchin embryo has been used to monitor pollutants in marine environments. Nickel (Nickel chloride, Ni), as a heavy metal, is a chemical element with the chemical formula NiCl 2-OH 2O. It may cause harmful effects on the central nervous system and growth. Metallothionein (MT) is a metal binding protein and it play a regulatory role in the homeostasis and detoxification of heavy metals. In this study, we examined the gametotoxic and embryotoxic effects of Ni at various concentrations (O, 10, 25, 50, 100, 500 ppb) in the sea urchin Hemicentrotus pulcherrimus. Spawning was induced by injecting 1 ml of 0.5 M KCl into coelomic cavity. Experiment was begun within 30 min the collection of both gametes. The fertilization and embryo development rates test were performed for 10 min and 64 h after fertilization, respectively. Results of this study, the fertilization rates in the control condition (not including Ni) and experimental group were not significantly changed. However, the embryo development rates were significantly decreased with concentration dependent manner. Especially, 50 ppb Ni treatment was significantly lower than vehicle control at 64 h onward. The normal embryogenesis rate was significantly inhibited in exposed to Ni (ECa,=34.19 ppb, 95% 01=29.56-38.09 ppb). The NOEC and LOEC of normal embryogenesis rate were <10 ppb and 25 ppb, respectively. The expression of MT mRNA gene was significantly increased with concentration dependent manner. These results suggest that the early embryo stages oí H. pulcherrimus have toxic effect at greater than 25 ppb of Ni concentration and MT mRNA gene may be used as a biomarker gene for risk assessment on contamination of Ni..
76. Xiubao Chen, Jian Yang, Hongbo Liu, Yaping Su, Lei Sun, Yuji Oshima, Element concentrations in a unionid mussel (anodonta woodiana') at different life stages, Journal of the Faculty of Agriculture, Kyushu University, 57, 1, 139-144, 2012.02, The 'background' levels of 18 elements (Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, and Tl) were measured in unionid mussels (Anodonta woodiana) at three different life stages (i.e., glochidia-whole body, juveniles and gravid adults-whole soft tissue). Field-collected adult mussels were cultured in experiment ponds for one year before used for tissue collection. Matured glochidia were collected from the adults for the element measurement and the culture of the juvenile mussels. The results of principal component analysis of the element concentrations indicated a significant life stage-dependent variation of element accumulation. The concentrations of Ca, Fe, Zn, As, Cd, Ni, and Mn were generally higher in the adult mussels than those in the juvenile mussels. However, several elements (e.g., Co, Cu, Mo, Ag) were significantly higher in the juveniles than those in the adults. Manganese appeared to be accumulated at high concentration in all three life stages. The background residue concentrations of heavy metals and toxic elements in the artificially produced mussels were very low, while that contaminated As in gravid adults was still obviously high, suggesting that the formers will be potentially more suitable to be used as the bioindicators for the corresponding elements by wild transplantation or laboratory exposure study rather than the gravid adults..
77. Xuchun Qiu, Yasuhiro Yamasaki, Yohei Shimasaki, Hiroaki Gunjikake, Tadashi Matsubara, Sou Nagasoe, Takuya Etoh, Shigeaki Matsui, Tsuneo Honjo, Yuji Oshima, Growth interactions between the raphidophyte Chattonella antiqua and the dinoflagellate Akashiwo sanguinea, Harmful Algae, 10.1016/j.hal.2011.08.001, 11, 81-87, 2011.11, We investigated the growth interactions between the raphidophyte Chattonella antiqua and the dinoflagellate Akashiwo sanguinea by using bi-algal cultures under axenic conditions. When initial cell densities of C. antiqua and A. sanguinea both were 1×102 cells ml-1, C. antiqua grew faster and its growth inhibitory effect on A. sanguinea was stronger than that of A. sanguinea on C. antiqua. In other combinations of inoculation densities, the species that was inoculated at lower cell density (1×102 cells ml-1) stopped growing soon after the start of the experiments, and cell density of this species gradually decreased after the other species reached early stationary phase. The mathematical model used to simulate the growth and interactions between the two species predicts that C. antiqua and A. sanguinea will approach an unstable equilibrium point of about 2.16×104 cells ml-1 (C. antiqua) and 1.46×104 cells ml-1 (A. sanguinea). Thus, one of the species always inhibits the growth of the other and their initial cell densities are critical in determining the successful species in growth competition. When one of these two species was inoculated at the cell density of 2×103 cells ml-1 in bi-algal culture experiments under noncontact and contact conditions, its growth inhibitory effect toward the other species was greater under contact conditions than under noncontact conditions. Furthermore, enriched filtrate from dense culture of C. antiqua resulted in both reduced maximum yield and maximum growth rate of A. sanguinea, whereas that of A. sanguinea resulted only in reduced maximum yield of C. antiqua but did not affect its growth rate..
78. Shizuho Miki, Koichi Ikeda, Yumi Oba, Hina Satone, Masato Honda, Yohei Shimasaki, Norio Onikura, Osamu Arakawa, Yuji Oshima, Tributyltin in blood of marine fish collected from a coastal area of northern Kyushu, Japan, Marine Pollution Bulletin, 10.1016/j.marpolbul.2011.08.043, 62, 11, 2533-2536, 2011.11, We investigated levels of the pollutant tributyltin (TBT) in blood of pufferfishes (six species), Japanese sea perch, red sea bream, Japanese common goby, Japanese flounder, rockfish, conger eel, and sea mullet collected off the coast of northern Kyushu, Japan. We found considerable levels of TBT (1.4-190. ng/mL) accumulated in the blood of these fish. Blood TBT concentrations were 1.3-22.5. times liver concentrations and 4.9-78. times muscle concentrations, except in conger eel and mullet. We detected TBT (16-111. ng/mL-blood) in the plasma of the fine-patterned puffer (Takifugu poecilonotus) year-round, without any apparent seasonal trend. These results suggest that fish inhabiting coastal areas of Kyushu, Japan, continue to be contaminated with TBT..
79. Xiu bao Chen, Jian Yang,Hongbo Liu, Yaping Su, Lei Sun and Yuji Oshima. , Element Concentrations in a Unionid Mussel (Anodonta woodiana) at Different Life Stages J. Fac. Agr. Kyushu Univ. 57, J. Fac. Agr. Kyushu Univ. , 57, 2011.10.
80. Un Ki Hwang, Jong Soo Park, Jong No Kwon, Seung Heo, Yuji Oshima, Han Seung Kang, Effect of Nickel on Embryo Development and Expression of Metallothionein Gene in the Sea Urchin (Hemicentrotus pulcherrimsu). J. Fac. Agr. Kyushu Univ. 57:, J. Fac. Agr. Kyushu Univ. , 57, 2011.10.
81. Qiu X, Yamasaki Y, Shimasaki Y, Gunjikake H, Matsubara T, Nagasoe S, Etoh T, Matsui S, Honjo T, Oshima Y. , Growth interactions between the raphidophyte Chattonella antiqua and the dinoflagellate Akashiwo sanguinea. , Harmful Algae. , 11, 81-87, 2011.09.
82. Dong Myung Kim, Min Ji Heo, Seok Jin Oh, Chang Geun Choi, Young Seok You, Hyeon Seo Cho, Ik Joon Kang, Yuji Oshima, Prediction of the transport and fate of polycyclic aromatic hydrocarbons (PAHs) in Masan Bay, South Korea, Journal of the Faculty of Agriculture, Kyushu University, 56, 2, 299-305, 2011.09, A numerical simulation of the polycyclic aromatic hydrocarbons (PAHs) in Masan Bay, Korea, was conducted using a program written in STELLA to estimate the transport of organic chemicals in the coastal environment. A sensitivity analysis of dissolved PAHs and PAHs in suspended particulate matter (SPM) indicated that PAH levels were significantly influenced by the settling velocity, the adsorption and desorption rates. PAHs in phytoplankton were sensitive to all coefficient. The mass balance model indicated that the standing stocks of PAHs in water, in SPM, and in phytoplankton were 2.01×l0 4g, 1.15×l0 3g, and 7.5×l0 -1g, respectively. Flux were characterized by a high rate of desorption, followed by descending rates of adsorption, settling, and flow to the open sea. The scenario predicted a "safe" concentration level of dissolved PAHs of less than 30 ng/L if the input loads from rivers, the atmosphere, or both rivers and the atmosphere were reduced to 50%, 50%, or 30% of the current levels, respectively..
83. Takeshi Hano, Yuji Oshima, Masato Kinoshita, Minoru Tanaka, Noriko Mishima, Yuko Wakamatsu, Kenjiro Ozato, Yohei Shimasaki, Tsuneo Honjo, Evaluation of the effects of ethinylestradiol on sexual differentiation in the olvas-GFP/STII-YI medaka (transgenic Oryzias latipes) strain as estimated by proliferative activity of germ cells, Aquatic Toxicology, 10.1016/j.aquatox.2011.04.013, 104, 3-4, 177-184, 2011.08, We evaluated the effects of 17(-ethinylestradiol (EE2) on sexual differentiation in transgenic olvas-GFP/STII-YI medaka (Oryzias latipes) in terms of the proliferative activity of germ cells. This strain contains the green fluorescent protein (GFP) gene fused to the regulatory region of the medaka vasa gene, and germ cell-specific expression of GFP can be visualized in living (transparent) individuals. From 0 days post-hatch (0dph) onwards, juveniles were exposed to graded concentrations of EE2 (25.2-1710ng/L) for 35 days. The gonads of live specimens were monitored by measuring their size and calculating their GFP-fluorescence area. GFP-fluorescent area in control females was about 10 times that in control males at 10 days posthatch (dph) whereas the gonadal size of 10dph males that had been exposed to 158ng/L of EE2 significantly increased up to twice the size of control males, indicating that abnormal sexual differentiation towards female might occur in these individuals. Histological examination and identification of the sex-linked marker SL1 indicated that male to female sex reversal occurred at EE2 exposure ≥45.1ng/L at 35dph. These results suggest that observation of proliferative activity of germ cells in the olvas-GFP/STII-YI strain could be applied to facilitated screening fish model to detect adverse effects on sexual differentiation as early as 10dph juveniles..
84. Kei Nakayama, Naomi Sei, Itsuki C. Handoh, Yohei Shimasaki, Tsuneo Honjo, Yuji Oshima, Effects of polychlorinated biphenyls on liver function and sexual characteristics in Japanese medaka (Oryzias latipes), Marine Pollution Bulletin, 10.1016/j.marpolbul.2011.01.015, 63, 5-12, 366-369, 2011.07, The effects of polychlorinated biphenyls (PCBs) on liver function and their differences between sexes were analyzed in Japanese medaka (Oryzias latipes) exposed to PCB126 or Kanechlor-400 (KC-400) using microarray. PCB exposure induced vitellogenin 1 expression in female medaka while suppressing choriogenin genes, which suggests that the effects of PCBs on estrogen-responsive genes do not occur directly through an estrogen receptor-mediated pathway. Reduction of androgen receptor alpha expression was also observed, and the gene expression pattern in PCB-exposed males changed to become more similar to that of females. Furthermore, changes in glycolysis-related genes indicate that PCB exposure might enhance glucose production via gluconeogenesis in the liver of medaka. Taken together, our results suggest that PCBs disrupt the endocrine system, especially androgen function, and may have the potential to cause demasculinizing effects. Additionally, induction of gluconeogenesis might be a response to maintain glucose levels consumed as a result of PCB exposures..
85. Kim Dong-Myung, Heo Min Ji, Oh Seok Jin, Choi Chang Geun, You, Young-Seok,Cho, Hyeon-Seo, Kang Ik Joon, Oshima, Yuji, Prediction of the Transport and Fate of Polycyclic Aromatic Hydrocarbons (PAHs) in Masan Bay, South Korea , J. Fac. Agr. Kyushu Univ. , 56, 2011.05.
86. Kim Dong-Myung, Heo Min Ji, Oh Seok Jin, Choi Chang Geun, You, Young-Seok,Cho, Hyeon-Seo, Kang Ik Joon, Oshima, Yuji, Prediction of the Transport and Fate of Polycyclic Aromatic Hydrocarbons (PAHs) in Masan Bay, South Korea , J. Fac. Agr. Kyushu Univ. , 56, 2011.05.
87. Hina Satone, Man Lee, Yumi Oba, Takahiro Kusakabe, Eriko Akahoshi, Shizuho Miki, Nobuo Suzuki, Yuichi Sasayama, Mohamed Nassef, Yohei Shimasaki, Shun-Ichiro Kawabata, Tsuneo Honjo, Yuji Oshima, Tributyltin-binding protein type 1, a lipocalin, prevents inhibition of osteoblastic activity by tributyltin in fish scales, Aquatic Toxicology, 10.1016/j.aquatox.2011.02.009, 103, 1-2, 79-84, 2011.05, Tributyltin-binding protein type 1 (TBT-bp1) is a member of the lipocalin family of proteins which bind to small hydrophobic molecules. In this study, we expressed a recombinant TBT-bp1 (rTBT-bp1, ca. 35. kDa) in a baculovirus expression system and purified the protein from the hemolymph of silkworm larvae injected with recombinant baculovirus. After incubation of a mixture of rTBT-bp1 and TBT and its fractionation by means of gel filtration chromatography, TBT was detected in the elution peak of rTBT-bp1, confirming the binding potential of rTBT-bp1 for TBT. An assay of the ability of rTBT-bp1 or native TBT-bp1 (nTBT-bp1) to restore osteoblastic activity inhibited by TBT showed that co-treatment of the scales with rTBT-bp1 or nTBT-bp1 in combination with TBT restored osteoblastic activity in goldfish scales, whereas treatment with TBT alone significantly inhibited osteoblastic activity. These results suggest that TBT-bp1 as a lipocalin member might function to decrease the toxicity of TBT by binding to TBT..
88. Nassef M, Kato-Unoki Y, Furuta T, Nakayama K, Satone H, Shimasaki Y, Honjo T, Oshima Y. , Molecular cloning, sequencing, and gene expression analysis of tributyltin-binding protein type 1 in Japanese medaka fish, Oryzias latipes. , Zoological Science , 28:, 281-285, 2011.04.
89. Nakayama K, Sei N,. Handoh I, Shimasaki Y, Honjo T, Oshima Y. , Effects of polychlorinated biphenyls on liver function and sexual characteristics in Japanese medaka (Oryzias latipes). , Mar Poll Bull , 28:, (in printing), 2011.04.
90. Y. Yamasaki, Y. Ohmichi, T. Shikata, M. Hirose, Y. Shimasaki, Y. Oshima & T. Honjo. , Species-specific allelopathic effects off the diatom Skeletonema costatum. , Thalassas, 27, 21-32, 2011.04.
91. Satone H, Lee JM, Oba Y, Kusakabe T, Akahoshi E, Miki S, Suzuki N, Sasayama Y, Nassef M, Shimasaki Y, Kawabata S, Honjo T, Oshima Y , Tributyltin-binding protein type 1, a lipocalin, prevents inhibition of osteoblastic activity by tributyltin in fish scales. , Aquat Toxicol , 103, 79-84, 2011.04.
92. Hano T, Oshima Y, Kinoshia M, Tanaka M, Mishima N, Wakamatsu Y, Ozato K, Shi-masaki Y, Honjo T. , Evaluation of the effects of ethinylestradiol (EE2) on sexual differentiation in the olvas-GFP/STII-YI medaka (transgenic Oryzias latipes) strain as estimated by proliferative activity of germ cells. , Aquat Toxicol , (accepted), 2011.04.
93. Ye S, Yang J, Liu H, Oshima Y. , Use of Elemental Fingerprint Analysis to Identify Localities of Collection for the Large Icefish Protosalanx chinensis in Taihu Lake, China. , J. Fac. Agr. Kyushu Univ. , 56, 41-46, 2011.04.
94. Suzuki N, Yamaguchi K, Hayakawa K, Omori K, Takeda K, Tabata MJ, Kitamura K, Endo M, Wada S, Srivastav AK, Chowdgyry VS, Oshima Y, Hattori A. , Effects of inorganic mercury on osteoclasts and osteoblasts of the goldfish scales in vitro. , J. Fac. Agr. Kyushu Univ. , 56, 47-56, 2011.04.
95. Mohamed Nassef, Yoko Kato-Unoki, Tomohisa Furuta, Kei Nakayama, Hina Satone, Yohei Shimasaki, Tsuneo Honjo, Yuji Oshima, Molecular cloning, sequencing, and gene expression analysis of tributyltin-binding protein type 1 in Japanese medaka fish, Oryzias latipes, Zoological science, 10.2108/zsj.28.281, 28, 4, 281-285, 2011.04, The full-length cDNA sequence of tributyltin-binding protein type1 in Japanese medaka (Oryzias latipes) (Olat.TBT-bp1) was determined by means of rapid amplification of cDNA ends (RACE) of liver tissue. Analysis of the structure of the gene encoding Olat.TBT-bp1 revealed that the exonintron organization of this gene corresponds to that of the genes encoding lipocalin superfamily proteins, suggesting that Olat.TBT-bp1 can be categorized as a member of the lipocalin superfamily, which may play an important role in transportation, detoxification, and excretion of xenobiotic compounds. Reverse transcription - PCR revealed that Olat.TBT-bp1 was expressed mainly in the liver, and upregulation of its expression was detected 1, 2, and 4 weeks post hatching. Relative expression of the Olat.TBT-bp1 gene was significantly downregulated, compared with that in the solvent control, by exposure to tributyltin at 0.01 mg/l or triclosan at 1.7 mg/l. Further studies on Olat.TBT-bp1 expression in conjunction with other biochemical and physiological toxicities in response to chemical exposures are needed to increase our understanding and information of TBT-bps mechanisms and as molecular biomarkers of chemical exposures. The role of Olat.TBT-bp1 in xenobiotic detoxification and/or excretion needs more investigations..
96. Nobuo Suzuki, Koji Yachiguchi, Kazuichi Hayakawa, Katsunori Omori, Koji Takada, Makoto J. Tabata, Kei Ichiro Kitamura, Masato Endo, Shigehito Wada, Ajai K. Srivastav, Vishwajit S. Chowdhury, Yuji Oshima, Atsuhiko Hattori, Effects of inorganic mmercury on osteoclasts and osteoblasts of the goldfish scales in vitro, Journal of the Faculty of Agriculture, Kyushu University, 56, 1, 47-51, 2011.02, The fish scales are the major source of internal calcium requirement due to having a higher internal calcium reservoir than the body skeleton during the periods of drastic calcium demand, such as sexual maturation. Therefore, we developed original in vitro assay system using goldfish scales that contain osteoclasts and osteoblasts, and examined the direct effect of inorganic mercury (HgCl2) on osteoclasts and osteoblasts. In this assay system, we measured the activities of tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) as respective indicators of each activity in osteoclasts and osteoblasts. TRAP activity in the scales significantly decreased by the treatment of HgCl2 (10-5 to 10-3M) during 6 hrs of incubation. In addition, mRNA expressions of osteoclastic markers: TRAP and cathepsin K significantly decreased compared with control. In our knowledge, this is the first report of a direct effect of inorganic mercury on osteoclasts. On the other hand, ALP activity decreased after exposures of HgCl2 at a concentration of 10-6, 10-5 or 10-4M for 36 and 64 hrs, although its activity did not change after 6 and 18 hrs. The mRNA expression of metallothionein (MT) which is a metal-binding-protein that protects the organism from heavy metal, significantly increased by HgCl2 (10-4M) although insulin-like growth factor-I (osteoblastic marker) was less than those of control scales by treatment with HgCl2 (10-4M). These results suggests that osteoblasts may synthesize MT and protect from mercury until 18 hrs incubation. Thus, the scale in vitro assay system would be a useful means for analysis of heavy metal on bone metabolism..
97. Mohamed Nassef, Takahiko Tawaratsumita, Yumi Oba, Hina Satone, Kei Nakayama, Yohei Shimasaki, Tsuneo Honjo, Yuji Oshima, Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27, Marine Pollution Bulletin, 10.1016/j.marpolbul.2010.12.005, 62, 2, 412-414, 2011.02, In this study, individual Japanese flounder were intraperitoneally injected with 2μg tributyltin-d27 (TBT-d27) fish-1. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology..
98. Y. Yamasaki, Y. Ohmichi, T. Shikata, M. Hirose, Yohei Shimasaki, Yuji Oshima, T. Honjo, Species-specific allelopathic effects of the diatom skeletonema costatum, Thalassas, 27, 1, 21-32, 2011.02, We examined allelopathic effects of Skeletonema costatum on the growth of Heterosigma akashiwo, a major competitor of S. costatum. Growth of H. akashiwo was inhibited when it was exposed to S. costatum filtrates collected in the stationary and decline growth phases. During the decline phase, the filtrate had the strongest inhibitory effect. Deactivation of the allelopathic effect of S. costatum was not observed when the filtrate was preserved at room temperature for 30 days. Additionally, crude extracts greater than 3,500 Da, obtained by dialysis, did not inhibit the growth of H. akashiwo; that is, S. costatum produces low molecular weight allelochemicals. Furthermore, we examined the allelopathic effects of S. costatum on the growth of other species and determined that these effects were both species-specific and dependent upon the cell density of the target species. It is likely that the allelochemicals produced by S. costatum are chemically stable low molecular weight substances, and the allelopathy of S. costatum has the potential to affect the succession of phytoplankton species during dense blooms of S. costatum and/or after a decline in the bloom of S. costatum..
99. Shanshan Ye, Jian Yang, Hongbo Liu, Yuji Oshima, Use of elemental fingerprint analysis to identify localities of collection for the large icefish protosalanx chinensis in Taihu Lake, China, Journal of the Faculty of Agriculture, Kyushu University, 56, 1, 41-45, 2011.02, Concentrations of eighteen major and trace elements; Na, Mg, Al, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Tl, and Pb were studied in the large icefish Protosalanx chinensis collected from four sampling areas (Yixingtan, Jiaoshan, Pingtaishan and Sanshandao) in Taihu Lake, China. This species was rich in essential elements (e.g., Na, Mg, K, Ca, Zn) and was uncontaminated with potentially toxic elements (e.g., As, Ag, and Pb). Iron levels were lower than expected. Concentrations of Mg, Al, K, Ca, Mn, Cu, Zn and Se in P. chinensis showed significant differences (P<0.05) among sampling areas, clearly revealed by principal component analysis. Moreover, the origin of P chinensis specimens from these four areas of Taihu Lake, discerned by multivariate statistical analyses, was characterized consistently by elemental fingerprint analysis (EFA). The EFA method has broad potential to identify source populations of species and fishery products in the marketplace..
100. Yasuhiro Yamasaki, Yanan Zou, Jyoji Go, Tomoyuki Shikata, Yukihiko Matsuyama, Kiyohito Nagai, Yohei Shimasaki, Kenichi Yamaguchi, Yuji Oshima, Tatsuya Oda, Tsuneo Honjo, Cell contact-dependent lethal effect of the dinoflagellate Heterocapsa circularisquama on phytoplankton-phytoplankton interactions, Journal of Sea Research, 10.1016/j.seares.2010.07.006, 65, 1, 76-83, 2011.01, We used bi-algal culture experiments to investigate and verify the roles of growth interaction between Heterocapsa circularisquama and Prorocentrum dentatum in monospecific bloom formation. Growth of H. circularisquama was slightly inhibited when inoculated at 102cellsmL-1 along with P. dentatum at 104cellsmL-1. In other combinations of inoculation densities, P. dentatum density rapidly decreased to extremely low levels in the presence of H. circularisquama. We used a mathematical model to simulate growth and interactions of H. circularisquama and P. dentatum in bi-algal cultures. The model indicates that one species will always inhibit the growth of the other and that the relative initial cell densities of the species are critical in determining the outcome. When cultured together under conditions without cell contact, growth of H. circularisquama and P. dentatum was not inhibited. As with P. dentatum, the growth of Heterosigma akashiwo and Skeletonema costatum was inhibited in intact cell suspensions with H. circularisquama, but a nontoxic species, Heterocapsa triquetra, did not affect the growth of P. dentatum or the other species. Similarly, cell suspensions of H. circularisquama showed hemolytic activity toward rabbit erythrocytes, but those of H. triquetra did not. In addition, the cell-free supernatant of H. circularisquama cultures showed no significant hemolytic activity. These results suggest that H. circularisquama causes lethality in P. dentatum by direct cell contact in which live-cell-mediated hemolytic activity might be a contributing factor..
101. Yumi Oba, Akira Yamauchi, Yasuyuki Hashiguchi, Hina Satone, Shizuho Miki, Mohamed Nassef, Yohei Shimasaki, Takeshi Kitano, Miki Nakao, Shun Ichiro Kawabata, Tsuneo Honjo, Yuji Oshima, Purification and characterization of tributyltin-binding protein of tiger puffer, Takifugu rubripes, Comparative Biochemistry and Physiology - C Toxicology and Pharmacology, 10.1016/j.cbpc.2010.07.009, 153, 1, 17-23, 2011.01, We successfully purified Trub.TBT-bpα, a tributyltin (TBT) binding protein (bp) of the tiger puffer, Takifugu rubripes. Tiger puffer was injected intraperitoneally with TBT (1.0 mg/kg body weight) and Trub.TBT-bpα was purified from serum by ammonium sulfate fractionation, gel filtration chromatography and polyacrylamide gel electrophoresis. Gel electrophoresis revealed that the Trub.TBT-bpα has a molecular mass of approximately 48.5 kDa and contains at least 40% N-glycan. The deduced 212 amino acid sequence of the protein showed the highest identity (41%, 212 amino acid overlap and E-value: 9e-42) with TBT-binding protein type 1 (TBT-bp1) of Paralichthys olivaceus (Japanese flounder). Analysis of the gene structure of Trub.TBT-bpα suggests that this protein belongs to the lipocalin superfamily, which may be important in the accumulation and elimination of TBT. Phylogenetic analysis suggests that functionalization of TBT-bps has occurred during evolution, and that the functions of this group of proteins might be important for fish survival..
102. Xuchun Qiu, Yasuhiro Yamasaki, Yohei Shimasaki, Hiroaki Gunjikake, Tomoyuki Shikata, Tadashi Matsubara, Sou Nagasoe, Takuya Etoh, Shigeaki Matsui, Tsuneo Honjo, Yuji Oshima, Growth interactions between raphidophytes chattonella antiqua and Heterosigma akashiwo, Thalassas, 27, 1, 33-45, 2011, We investigated growth interactions between the raphidophytes Chattonella antiqua (Hada) Ono and Heterosigma akashiwo (Hada) Hada ex Hara et Chihara using bi-algal cultures under axenic conditions. The growth of C. antiqua and H. akashiwo each tended to be strongly suppressed when the other species reached early stationary phase. A mathematical model was used to simulate the growth interactions of C. antiqua and H. akashiwo in bi-algal cultures. The model showed that C. antiqua outcompetes H. akashiwo over time in bi-algal cultures under all experimental conditions. Furthermore, despite re-enrichment with nutrients, the filtrate from dense cultures of C. antiqua reduced the maximum growth rate of H. akashiwo and filtrate from dense cultures of H. akashiwo reduced both the maximum growth rate and maximum yield of C. antiqua..
103. Sou Nagasoe, Tomoyuki Shikata, Yasuhiro Yamasaki, Tadashi Matsubara, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of nutrients on growth of the red-tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee and a possible link to blooms of this species, Hydrobiologia, 10.1007/s10750-010-0301-0, 651, 1, 225-238, 2010.09, We investigated the impact of different nitrogen (N) and phosphorus (P) compounds and concentrations on the growth of Gyrodinium instriatum Freudenthal et Lee in laboratory experiments, and possible links to blooms of this species at Hakozaki Fishing Port, Fukuoka, Japan. G. instriatum utilized only inorganic N compounds as N sources for growth. In contrast, G. instriatum utilized many inorganic and organic phosphorus compounds. We used the Monod equation to describe the growth rate of G. instriatum in N- or P-limited batch cultures as a function of ambient nutrient concentrations. Kinetic growth parameters for maximum specific growth rate (μmax) and half-saturation nutrient concentration (KS) were 0.57 divisions d-1 and 14.2 μmol l-1, respectively, under N-limitation and 0.65 divisions d-1 and 1.75 μmol l-1, respectively, under P-limitation. Compared with these KS values, all in situ average dissolved inorganic nitrogen (DIN) concentrations in Hakozaki Fishing Port were higher than KS for N, but all in situ average dissolved inorganic phosphorus (DIP) concentrations were lower than KS for P, whether a red tide occurred or not bloom. Moreover, average DIP concentration in April (a month critical to red-tide genesis) of 2004 (a non-red-tide year) was less than half those in 2002 and 2003 (red-tide years). Thus, differences in DIP concentrations may be an important factor controlling blooms of G. instriatum in Hakozaki Fishing Port..
104. Mohamed Nassef, Shuhei Matsumoto, Masanori Seki, Fatma Khalil, Ikjoon Kang, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Acute effects of triclosan, diclofenac and carbamazepine on feeding performance of Japanese medaka fish (Oryzias latipes), Chemosphere, 10.1016/j.chemosphere.2010.04.073, 80, 9, 1095-1100, 2010.08, The toxicity of three pharmaceutical and personal care products (PPCPs) - carbamazepine (CBMZ), diclofenac (DCF), and triclosan (TCS) - was examined by measuring their effects on feeding behavior and swimming speed of adult Japanese medaka fish (Oryzias latipes). Medaka were exposed to 6.15mgL -1 CBMZ, 1.0mgL -1 DCF, 0.17mgL -1 TCS, or no PPCP (control) for 9d. Fish behaviors were monitored during days 5-9 of the exposure period. Feeding behavior (time to eat midge larvae, TE) and swimming speed (SS) of individual exposed and control fish were tracked in two dimensions, using an automated system with a digital charge-coupled device camera. As a result, feeding behavior was affected by exposure to CBMZ and DCF, while SS was altered by exposure to CBMZ and TCS. Thus, TCS, DCF and CBMZ appear to affect fish behaviors through different mechanisms. Overall, the results suggest that behavioral changes may provide a sensitive indicator for assessing the toxicity of PPCPs to aquatic organisms..
105. 本田匡人,郡司掛博昭,松井繁明,諸石淳也,姜益俊,島崎洋平,大嶋雄治. , サルボウガイ(Scapharca subcrenata)の呼吸代謝に及ぼす低酸素の影響. , 九州大学農学部学芸誌, 65, 31-37, 2010.07.
106. Mohamed Nassef, Sang Gyoon Kim, Masanori Seki, Ikjoon Kang, Takeshi Hano, Yohei Shimasaki, Yuji Oshima, In ovo nanoinjection of triclosan, diclofenac and carbamazepine affects embryonic development of medaka fish (Oryzias latipes), Chemosphere, 10.1016/j.chemosphere.2010.02.002, 79, 9, 966-973, 2010.05, We examined the toxicity of three pharmaceuticals and personal care products (PPCPs) - triclosan (TCS), diclofenac (DCF), and carbamazepine (CBMZ) - on embryonic development of Japanese medaka (Oryzias latipes) using in ovo nanoinjection. Medaka eggs (8 h post-fertilization; late blastula stage) were injected with 0.5 nL of triolein (vehicle control) or 0.5 nL of PPCPs, using different doses of TCS (1, 5, or 9 ng), DCF (1, 5, or 12 ng), or CBMZ (1, 5, or 12 ng) per egg in triolein, in addition to uninjected control. Following injection, we recorded survival, embryonic lesions, delay in embryonic development (eye, embryonic body and internal organs), heart beat rate, hatchability, and hatching time of embryos and upward swimming of larvae. As a result, injected PPCPs caused toxic responses to medaka embryos during embryonic development and around the day of hatching. Based on estimated EC50 values of PPCPs doses on survival of injected embryos at hatching, TCS (at a dose of 4.2 ng egg-1) was generally more toxic to medaka embryos, followed by DCF (6.0 ng egg-1), and CBMZ (13.1 ng egg-1). We conclude that the nanoinjection medaka embryos model is a valuable tool for analyzing the effects of chemicals on the development of fish embryos and feasibility of nanoinjecting PPCPs into small fish eggs perhaps mimicking early exposure resulting from oocyte uptake of contaminants from maternal extra gonadal tissues..
107. Nassef M , Matsumoto S, Seki M, khalil F, Kang IJ, Shimasaki Y, Oshima Y, Honjo T. , Acute effects of triclosan, diclofenac and carbamazepine on feeding performance of Japanese medaka fish (Oryzias latipes) , Chemosphere, 80: 1095-1100, 79:966-973 , 2010.04, The toxicity of three pharmaceutical and personal care products (PPCPs) – carbamazepine (CBMZ), diclofenac (DCF), and triclosan (TCS) – was examined by measuring their effects on feeding behavior and swimming speed of adult Japanese medaka fish (Oryzias latipes). Medaka were exposed to 6.15 mg L−1 CBMZ, 1.0 mg L−1 DCF, 0.17 mg L−1 TCS, or no PPCP (control) for 9 d. Fish behaviors were monitored during days 5–9 of the exposure period. Feeding behavior (time to eat midge larvae, TE) and swimming speed (SS) of individual exposed and control fish were tracked in two dimensions, using an automated system with a digital charge-coupled device camera. As a result, feeding behavior was affected by exposure to CBMZ and DCF, while SS was altered by exposure to CBMZ and TCS. Thus, TCS, DCF and CBMZ appear to affect fish behaviors through different mechanisms. Overall, the results suggest that behavioral changes may provide a sensitive indicator for assessing the toxicity of PPCPs to aquatic organisms..
108. Nagasoe S, Shikata T, Yamasaki Y, Matsubara T, Shimasaki Y, Oshima Y, Honjo T. , Effects of nutrients on growth of the red-tide dinoflagellate Gyrodinium instriatum et Lee and a possible link to blooms of this species Freudenthal. , Hydrobiologica 651:225-23, 79:966-973 , 2010.04.
109. Y. Yamasaki, Y. Zou, J. Go, T. Shikata, Y. Matsuyama, K. Nagai, Y. Shimasaki, K. Yamaguchi, Y. Oshima, T. Oda, T. Honjo,, Cell-contact-dependent lethal effect of the dinoflagellate Heterocapsa circularisquama on phytoplankton-phytoplankton interactions., Journal of Sea Research, 65, 76–83, 2010.04.
110. Oba Y, Yamauchia A, Hashiguchi Y, Satonea H, Miki S, Nassef M, Shimasaki Y, Kitano T, Nakao M, Kawabata S, Honjo T, Oshima Y, Purification and charac-terization of tributyltin-binding protein of tiger puffer, Takifugu rubripes. , Comp Biol phys C., 153, 17-23, 2010.04.
111. Qiu X, Yamasaki Y, Shimasaki Y, Gunjikake H, Shikata T, Matsubara T, Nagasoe S, Honjo T, Oshima Y. , Growth interactions between raphidophytes Chattonella antiqua and Heterosigma akashiwo. , Thalasas, 27, 33-45, 2010.04.
112. Nassef M, Tawaratsumida T, oba Y, Satoe H, Nakayama K, Shimasaki Y, Honjo T, Oshima Y. , Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27. , Mar Poll Bull , 62, 412-414, 2010.04.
113. Nassef M, Kim SG, Seki M, Kang IJ, Hano T, Shimasaki Y, Oshima Y. , In ovo nanoinjection of triclosan, diclofenac and carbamazepine affects embryonic development of medaka fish (Oryzias latipes). , Chemosphere , 79:966-973 , 2010.03.
114. Y. Yamasaki, S. Nagasoe, M. Tameishi, T. Shikata, Y. Zou, Z. Jiang, T. Matsubara, Y. Shimasaki, K. Yamaguchi, Y. Oshima, T. Oda, T. Honjo, The role of interactions between Prorocentrum minimum and Heterosigma akashiwo in bloom formation, Hydrobiologia, 10.1007/s10750-009-0052-y, 641, 1, 33-44, 2010.02, We examined the growth and interactions between the bloom-forming flagellates Prorocentrum minimum and Heterosigma akashiwo using bi-algal culture experiments. When both species were inoculated at high cell densities, growth of H. akashiwo was inhibited by P. minimum. In other combinations of inoculation densities, the species first reaching the stationary phase substantially suppressed maximum cell densities of the other species, but the growth inhibition effect of P. minimum was stronger than that of H. akashiwo. We used a mathematical model to simulate growth and interactions of P. minimum and H. akashiwo in bi-algal cultures. The model indicated that P. minimum always out-competed H. akashiwo over time. Additional experiments showed that crude extracts from P. minimum and H. akashiwo cultures did not affect the growth of either species, but both strongly inhibited the growth of the bloom-forming diatom Skeletonema costatum. Further experiments showed that it was unlikely that reactive oxygen species produced by H. akashiwo were responsible for the inhibition of P. minimum growth..
115. Yamasaki Y, Nagasoe S, Tameishi M, Shikata T, Zou Y, Jiang Z, Matsubara T, Shimasaki Y, Yamaguchi K, Oshima Y, Oda T, and Honjo T. , The role of interactions between Prorocentrum minimum and Heterosigma akashiwo in bloom formation. , Hydrobiologia , 2009.12.
116. Takeshi Hano, Yuji Oshima, Masato Kinoshita, Minoru Tanaka, Yuko Wakamatsu, Kenjiro Ozato, Mohamed Nassef, Yohei Shimasaki, Tsuneo Honjo, In ovo nanoinjection of nonylphenol affects embryonic development of a transgenic see-through medaka (Oryzias latipes), olvas-GFP/STII-YI strain, Chemosphere, 10.1016/j.chemosphere.2009.09.036, 77, 11, 1594-1599, 2009.12, We performed in ovo nanoinjection of 4-nonylphenol (NP) into embryos of a transgenic see-through medaka (Oryzias latipes), olvas-GFP/STII-YI strain, which has two genotypic sex markers, and examined the effects on development and sexual differentiation. The transgene consisted of a green fluorescent protein (GFP) gene fused to the regulatory region of the medaka vasa gene. Germ cell-specific GFP expression was visualized in the gonad through the transparent body wall of the living fish. The development of each embryo was observed after nanoinjection of 2.0, 10, 50, 125, or 250 ng of NP. NP administration caused significant higher mortality at ≥50 ng egg-1 and inhibited embryonic development, including abnormal hatch and swim-up failure in all treatment groups except 10 ng egg-1 group. However, it did not cause adverse effects on germ cell proliferation by 10 d posthatch (dph) or sex differentiation of survivors by 100 dph. We concluded that single-dose in ovo exposure to nonylphenol affected embryonic development in the medaka but not gonadal development by 10 dph or sexual differentiation in adult fish by 100 dph. Although further investigations might be needed to elucidate the usefulness of nanoinjection of embryos of this strain, present study indicated that the nanoinjection model using olvas-GFP/STII-YI strain medaka has potential for use in evaluating the effects of chemicals on early development and sexual differentiation..
117. Yuji Oshima, Reproductive physiological and biochemical studies on the effect of tributyltin to fish and shellfish, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.75.354, 75, 3, 354-356, 2009.12.
118. Ikjoon Kang, Junya Moroishi, Mitoshi Yamasuga, Sang Gyoon Kim, Yuji Oshima, Swimming behavioral toxicity in Japanese Medaka (Oryzias latipes) exposed to various chemicals for biological monitoring of water quality, Atmospheric and Biological Environmental Monitoring, 10.1007/978-1-4020-9674-7_20, 285-293, 2009.12, We conducted a short-term behavioral toxicity test in medaka (Oryzias latipes). Fish were exposed to toxicants (potassium cyanide [1 or 5∈mg/L], phenol [12.5 or 25∈mg/L], fenitrothion [10 or 20∈mg/L], or benthiocarb [10 or 20∈mg/L]), and swimming behavior was recorded and evaluated for 1∈h. The medaka were placed in an exposure chamber with a continuous flow-through system. Two cameras tracked the fish at positions to the front and side of the test chamber, and images from the cameras were used to calculate the positions of the medaka in three dimensions (3D); the 3D data were processed by computer and analyzed as swimming activity (swimming speed and surfacing behavior).The swimming behavior of medaka was affected by exposure to toxic chemicals. The frequency of fast swimming was remarkably increased in medaka treated with potassium cyanide (5∈mg/L), phenol (25∈mg/L), or fenitrothion (10 or 20∈mg/L). An increase in the time spent close to the water surface was observed in fish exposed to potassium cyanide (1 or 5∈mg/L), fenitrothion (10 or 20∈mg/L), or benthiocarb (20∈mg/L). We concluded that pollution of water with these toxic chemicals at high concentrations can be detected by monitoring the swimming behavior of medaka for 1∈h..
119. Yuji Oshima, Kei Nakayama, Hano Takeshi, Sang Gyoon Kim, Yohei Shimasaki, Ik Joon Kang, Tsuneo Honjo, Toxic interactions between tributyltin and polychlorinated biphenyls in aquatic organisms, Ecotoxicology of Antifouling Biocides, 10.1007/978-4-431-85709-9_11, 195-205, 2009.12, In recent years, discharges of anthropogenic chemicals to the environment have been increasing in association with industrial development. These chemicals and their degradation products are released to the environment, discharged into water, and may ultimately contaminate aquatic organisms. Polychlorinated biphenyls (PCBs) and tributyltin (TBT) are particularly ubiquitous pollutants..
120. Junya Moroishi, Ik Joon Kang, Ken Nagafuchi, Tsuneo Honjo, Yohei Shimasaki, Yuji Oshima, Biological monitoring to detect both water pollution and water quality recovery based on valve movements of freshwater bivalves (Corbicula japonica), Journal of the Faculty of Agriculture, Kyushu University, 54, 2, 413-420, 2009.10, The valve movement pattern of the freshwater bivalve Corbicula japonica (C. japonica) following exposure to test chemicals was monitored. We conducted the exposure test with two heavy metal compounds, cadmium chloride (CdCl 2; 0, 0.1, 1, or 10 mg/L) and copper (II) chloride (CuCl 2; 0, 0.1, 1, or 10 mg/L) in a continuous flow system. After a pre-exposure period in a test chamber, which was filled with dechlorinated tap water for 1 h, the bivalves were exposed to the test chemicals for 3 h. After that, only dechlorinated tap water was released again into the test chamber for 2 h. Thus, the valve movements were continuously recorded for a total of 6 h. On exposure to CdCl 2 (1 and 10 mg/L), the valve movement of C. japonica closed. However, the valve movements of C. japonica in all CdCl 2 groups recovered after termination of the exposure. C. japonica showed decreased distance between the valves on exposure to CuC 2 (0.1,1, and 10 mg/L). However, C. japonica restarted their valve movements only in the recovery period at 0.1 mg/L CuCl 2. Therefore, we conclude that real-time monitoring of the valve movement of C. japonica is a useful method to detect both the contamination with a toxicant and recovery of the water quality in an aquatic ecosystem. In addition, it can be used for the assurance of the water quality..
121. Mohamed Nassef, Shuhei Matsumoto, Masanori Seki, Ik Joon Kang, Junya Moroishi, Yohei Shimasaki, Yuji Oshima, Pharmaceuticals and personal care products toxicity to Japanese medaka fish (Oryzias latipes), Journal of the Faculty of Agriculture, Kyushu University, 54, 2, 407-411, 2009.10, We evaluated the acute toxicity of some pharmaceuticals and personal care products (PPCPs) to the survival of Japanese medaka (Oryzias latipes). Adult medaka were exposed to different concentrations of triclosan (TCS; 1, 2, 2.4 and 3mg/L), diclofenac (DCF; 9,12,15 and 18mg/L) or carbamazepine (CBMZ; 60, 65, 70, 90 and 100 mg/L) for 96 h in a semi-static water exposure system. In order of decreasing toxicity to medaka, the 96-h LC 50 values were TCS, 1.7 mg/L; DCF, 10.1 mg/L; and CBMZ, 61.5 mg/L. We compared the no observed effect concentration (NOEC) determined from this study with the predicted environmental concentrations (PEC) and concluded that TCS and DCF pose potential risks to medaka but the risk from CBMZ is negligible..
122. Yang J, Oshima Y, Ito S, Miyazaki N., Metabolism of tributyltin and phenyltin by Dall’s porpoise hepatic microsomes. , Chemosphere , 76: 1013-1015., 2009.08.
123. Ohtsubo M., Higashi T., Kanayama M., Inoue S., Oshima Y.. 2009. , Distribution and correlation of tributyltin and organic matter in the sediments of Hakata Bay, Japan. , J Test Evalu , 76: 1013-1015., 2009.08.
124. Moroishi J, Kang IJ, Nagafuchi K, Honjo T, Shimasaki Y and Oshima Y. , Biological monitoring to detect both water pollution and water quality recivery on valve movements of fresh water bivalves., J. Fac. Agr. Kyushu Univ. 55:413-420., 76: 1013-1015., 2009.08.
125. Nassef M, Matsumoto S, Seki M, Kang IJ, Moroishi J, Shimasaki Y and Oshima Y., Pharmaceuticals and personal care products toxicity to medaka fish. . , J. Fac. Agr. Kyushu Univ. 2009;55:407-411., 76: 1013-1015., 2009.08.
126. Kang IK, Moroishi J, Yamasuga M, Kim SG and Oshima Y. , Swimming behavioral toxicity in Japanese medaka (Oryzias latipes) Exposed to various chemicals for biological monitoring of water quality. , Atmos Biol Environ Monitor Part III , 285-293., 2009.08.
127. Kang IK, Moroishi J, Yamasuga M, Kim SG and Oshima Y. , Swimming behavioral toxicity in Japanese medaka (Oryzias latipes) Exposed to various chemicals for biological monitoring of water quality. , Atmos Biol Environ Monitor Part III , 285-293., 2009.08.
128. Hano T, Kinoshita M, Tanaka M, Y. W, Ozato O, Shimasaki Y, Oshima Y and Honjo T., Ovo nanoinjection of nonylphenol affects embryonic development of olvas-GFP/ST-II YI medaka, Oryzias latipes., Chemosphere , 77:1594-1599., 2009.08.
129. Jian Yang, Yuji Oshima, Ito Sei, Nobuyuki Miyazaki, Metabolism of tributyltin and triphenyltin by Dall's porpoise hepatic microsomes, Chemosphere, 10.1016/j.chemosphere.2009.05.010, 76, 7, 1013-1015, 2009.08, The in vitro metabolism of tributyltin (TBT) and triphenyltin (TPT) by the hepatic microsomal cytochrome P-450 system enzymes of Dall's porpoises (Phocoenoides dalli) was comparatively elucidated with those enzymes of the Sprague Dawley rat in the present study. Our results suggested firstly a limited metabolic capacity for TBT and especially TPT to their metabolites in the Dall's porpoises, and documented a similar mechanism of a relatively stronger metabolic rate of TBT to its metabolites than that of TPT in the microsome of porpoises and rat. However, the metabolic capacity to degrade both TBT and TPT were much lower in the microsome of porpoises than that in the rats..
130. Yasuhiro Yamasaki, Tomoyuki Shikata, Atsushi Nukata, Satoko Ichiki, Sou Nagasoe, Tadashi Matsubara, Yohei Shimasaki, Miki Nakao, Kenichi Yamaguchi, Yuji Oshima, Tatsuya Oda, Makoto Ito, Ian R. Jenkinson, Makio Asakawa, Tsuneo Honjo, Extracellular polysaccharide-protein complexes of a harmful alga mediate the allelopathic control it exerts within the phytoplankton community, ISME Journal, 10.1038/ismej.2009.24, 3, 7, 808-817, 2009.07, The goal of this study was to examine the significance of allelopathy by the raphidophyte Heterosigma akashiwo in a multispecies phytoplankton community in the field. Towards this aim, we sought allelochemicals of H. akashiwo, which had allelopathic effect both in laboratory experiments and in the field. As an initial step, we showed that the allelopathic effects of H. akashiwo filtrate were both species-specific and dependent upon the cell density of the target species. Secondly, we found for the first time that extracellular, high-molecular weight allelochemicals that is, polysaccharide-protein complexes (APPCs) were produced by a marine phytoplankton species, H. akashiwo. Thirdly, we indicated that the purified APPCs selectively inhibited the growth of the diatom Skeletonema costatum that is a major competitor of H. akashiwo, and thereby tended to promote the formation of monospecific H. akashiwo blooms. Furthermore, we demonstrated that the inhibitory effect of APPCs on the growth of the diatoms was determined by binding to the cell surface of the target species. Finally, we succeeded in the detection of APPCs in the field samples at concentrations exceeding their experimentally determined action threshold during the H. akashiwo bloom. Strategies for ecosystem control, including mitigation of harmful algal blooms (HABs), should take into account that red-tide organisms like H. akashiwo are already part of complex webs involving inter-specific allelopathic inhibition and ecosystem control during their dense blooms..
131. Leila Basti, Kyohito Nagai, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Susumu Segawa, Effects of the toxic dinoflagellate Heterocapsa circularisquama on the valve movement behaviour of the Manila clam Ruditapes philippinarum, Aquaculture, 10.1016/j.aquaculture.2009.02.029, 291, 1-2, 41-47, 2009.06, The effects of the toxic dinoflagellate Heterocapsa circularisquama on the valve movements of adult Ruditapes philippinarum (Bivalvia, Veneridae) were investigated. The valve movement behaviour was continuously measured using a non invasive Hall element sensor-automated data acquisition system. Individual clams acclimated to the experimental conditions were subjected to different food regimes over a 96 h period: (1) unfed in filtered seawater for the first 24 h, (2) batch-fed1, in which clams were given one ration of non-toxic Isochrysis galbana at the beginning of the second 24 h, (3) batch-fed2, in which clams were given a mixture of I. galbana and H. circularisquama (5 × 104 cells ml- 1) for the third 24 h, and (4) starved for 24 h in filtered seawater after exposure to the toxic alga. For each food regime, the valve activity was analyzed by quantifying: (1) the duration of valve opening (DVO, %), (2) the amplitude of valve opening (AVO, mm), and (3) the frequency of valve adductions (FVA, adductions h- 1). The real-time monitoring of the clams' valve movements proved that R. philippinarum detects H. circularisquama in the mixture of food at as low as 0.5 cells ml- 1. Typically, the addition of the toxic alga induced a short and incomplete valve closure reaction. A strong correlation between the closure reaction time and H. circularisquama concentration was found (R2 = 0.91), the closure reaction occurring faster with increasing concentrations. Reopening of the valves was characterized by a significant increase in the FVA starting from 5 cells ml- 1 (ANOVA, P < 0.001) and a significant decrease in the AVO at 500 cells ml- 1 (Wilcoxon, P < 0.05). After exposure, clams transferred to clean seawater resumed normal valve adduction activity, but showed a significant increase in the DVO after exposure to 0.5 and 5 cells ml- 1 (ANOVA, LSD, P < 0.05), and a significant increase in the AVO (ANOVA, P < 0.01). Such increase could have been associated with recovery behaviour. Our results indicate that the Manila clam is highly sensitive to the toxic H. circularisquama and detects efficiently its presence at extremely low concentrations, in mixture of food, and in a time- and concentration-dependent manner. The Manila clam and the valve movement monitor could thus be used as an early biological warning system to monitor the outbreaks of this toxic alga along marine coastal areas and in bivalve farms. However, field experiments are required to provide further evidence for the use of this monitor in natural environment where several factors may interfere with the valve movement behaviour..
132. M. Ohtsubo, T. Higashi, M. Kanayama, S. Inoue, Y. Oshima, Distribution and correlation of tributyltin and organic matter in the sediments of hakata bay, Japan, Journal of ASTM International, 10.1520/JAI102101, 6, 5, 2009.05, Tributyltin (TBT) is used as effective antifouling agents In boat paints and has been found to be present In marine and freshwaters ecosystem at concentrations exceeding acute and chronic toxicity levels. In the present study, horizontal and vertical TBT distributions In the sediment of Hakata Bay, Japan, have been investigated. Basic properties of the sediment such as clay mineralogy, particle size and organic matter content were also determined, and their relations with TBT concentrations In the sediment were discussed, focusing on organic matter. Sediments In the study sites consist mostly of clay soil with clay fraction of 21 % to 35 %, and major clay minerals in the sediments were smectite, followed by vermlcullte, and kaolinite. TBT concentration in overlying water ranged from 13 to 94 ng.L1 at locations within the harbor, and from 13 to 32 ngL 1 at locations outside of the harbor. TBT concentration In top 3 cm sediment varied from 0.018 to 1.101 mgkg- 1. Sorption coefficient was In a range of 1.03 to 5.7X103 (L kg-1) for sediments at most stations, and on the order of 10 4 for sediments with higher organic matter content, The organic matter content and TBT concentration in sediments changed with depth In a similar pattern at all stations. The organic matter decreased with depth up to 12 cm and was almost constant below 12 cm. TBT concentrations appeared to be higher at depth above 12 cm than below 12 cm. A positive correlation was observed between TBT concentration and organic matter content for all core samples data. According to other researchers, an Increase in TBT concentration due to increase In organic matter appears to be the results of sorption of TBT+ on negatively charged surfaces of organic matter as well as hydrophobic sorption of TBT compounds on oraanlc matter..
133. Shikata T, Nukata A, Yoshikawa S, Matsubara T, Yamasaki Y, Shimasaki Y, Oshima Y, Honjo T. , Effects of light quality on initiation and development of meroplanktonic diatom blooms in a eutrophic shallow sea. , Marine Biology , 156: 875-889., 2009.04.
134. Tomoyuki Shikata, Atsushi Nukata, Souta Yoshikawa, Tadashi Matsubara, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of light quality on initiation and development of meroplanktonic diatom blooms in a eutrophic shallow sea, Marine Biology, 10.1007/s00227-009-1131-3, 156, 5, 875-889, 2009.04, We investigated the effects of light quality on resting stage cell germination and vegetative cell growth of meroplanktonic diatoms in a small port in Hakata Bay, Japan and in the laboratory. During the investigation over the year of 2006, the meroplanktonic diatom bloom first occurred in the end of May and then repeated wane and wax until October in the small port. From late April to middle May, light penetrating the water column was often strong and attenuations of all spectral lights were low. During this period, Skeletonema costatum, Thalassiosira minima, and Chaetoceros sp. appeared frequently, followed by the blooms of S. costatum and Chaetoceros sp. in late May. Thereafter, S. costatum and Chaetoceros sp. bloomed in late June but not in middle June, when pigmented flagellates bloom appeared. The attenuation of short-wavelength light such as violet and blue lights was markedly high during these diatom and flagellate blooms; all blooms disappeared within several days. Vegetative cell strains of the three diatoms under light emitting diodes (LEDs) with six different spectra (violet, blue, green, orange, red, and near-infrared) grew at a higher rate under short-wavelength light, violet and blue. On the other hand, when suspensions of bottom sediments from Hakata Bay were cultured under the same LEDs and in the dark, vegetative cells of S. costatum appeared under all LEDs except for orange and near-infrared, vegetative cells of T. minima appeared under all LEDs but not in the dark, and vegetative cells of Chaetoceros sp. appeared under violet and blue LEDs. However, vegetative cell densities of the three diatoms increased much more under violet light than under other LEDs within a short period (6 days). Our study indicates that underwater penetration by short-wavelength light, such as violet and blue, may be an important factor in the initiation and development of meroplanktonic diatom blooms..
135. Tameishi M, Yamasaki Y, Nagasoe S, Shimasakia Y, Oshima Y, Honjo T. , Allelopathic effects of the dinophyte Prorocentrum minimumon the growth of the bacillariophyte Skeletonema costatum. , Harmful Algae , 8: 421-429, 2009.02.
136. Yamasaki Y, Shikata T, Nukata A, Ichiki S, Nagasoe S, Matsubara T, Shimasaki Y, Nakao M, Yamaguchi K, Oshima Y, Oda T, Ito M, Jenkinson IR, Asakawa M, Honjo T. , Extracellular polysaccharide-protein complexes of a harmful alga mediate the allelopathic control it exerts within the phytoplankton community., ISME Journal, 3: 808-17, 2009.02.
137. Kang IJ, Moroishi J, Nakamura A, Nagafuchi K, Kim SG, Oshima Y. , Biological monitoring of detection of toxic chemicals in water by the swimming behavior of small freshwater fish., Journal of the Faculty of Agriculture Kyushu University, 54: 209-214, 2009.02.
138. Masayuki Tameishi, Yasuhiro Yamasaki, Sou Nagasoe, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Allelopathic effects of the dinophyte Prorocentrum minimum on the growth of the bacillariophyte Skeletonema costatum, Harmful Algae, 10.1016/j.hal.2008.09.002, 8, 3, 421-429, 2009.02, We investigated growth interactions between the dinophyte Prorocentrum minimum and the bacillariophyte Skeletonema costatum using bi-algal cultures under axenic conditions. When low cell densities of P. minimum and high cell densities of S. costatum were inoculated into the same medium, growth of P. minimum was suppressed. Other inoculum combinations resulted in reduced S. costatum maximum cell densities. A mathematical model was used to simulate growth and interactions of P. minimum and S. costatum in bi-algal cultures. The model indicated that P. minimum always outcompeted S. costatum over time. Enriched filtrate from low-density P. minimum cultures significantly stimulated S. costatum growth, but enriched filtrate from high-density P. minimum cultures notably inhibited the growth of S. costatum. Growth of P. minimum was not affected by enriched filtrate from cultures of P. minimum at any density. Filtrates of P. minimum cultures were fractionated by ultrafiltration (molecular weight cutoff >3000 Da), and retentate that included polysaccharide(s) significantly inhibited the growth of S. costatum..
139. Ik Joon Kang, Junya Moroishi, Ayumi Nakamura, Ken Nagafuchi, Sang Gyoon Kim, Yuji Oshima, Biological monitoring for detection of toxic chemicals in water by the swimming behavior of small freshwater fish, Journal of the Faculty of Agriculture, Kyushu University, 54, 1, 209-214, 2009.02, We conducted exposure tests using three small fish species, medaka (Oryzias latipes), guppy (Poecilia reticulata), and white cloud mountain minnow (Tanichthys albonubes). The fish were exposed to nominal concentrations of test chemicals (potassium cyanide [KCN; 1 and 5mg/L], sodium cyanide [NaCN; 1 and 5 mg/L], and aldicarb [5 mg/L]) for one hour. We used two cameras for tracking the fish behavior in three dimensional (3D) data. Then the 3D data were analyzed for fish behavior such as, swimming speed and surfacing behavior. Swimming speed and position of the three fish species were affected by KCN, NaCN, and aldicarb exposure test. Three fish species showed the different behavioral patterns after the exposure of test chemicals. Although the patterns of effect on behavioral parameters differed among the test species and toxic chemicals, we could find the significant effects on both the frequency of high swimming speed and duration time of surfacing behavior in test fish. We concluded that three fish species are useful species for monitoring the water quality by their behavioral changes..
140. Satone H, Oshima Y, Shimasaki Y, Tawaratsumita T, Oba Y, Takahashi E, Kitano T, Kawabata S, Kakuta Y, Honjo T., Tributyltin-binding protein type 1 has a distinctive lipocalin-like structure and is involved in the excretion of tributyltin in Japanese flounder, Paralichthys olivaceus. , Aquatic Toxicology, 90: 292-299., 2008.12.
141. Hina Satone, Yuji Oshima, Yohei Shimasaki, Takahiko Tawaratsumida, Yumi Oba, Eriko Takahashi, Takeshi Kitano, Shun-Ichiro Kawabata, Yoshimitsu Kakuta, Tsuneo Honjo, Tributyltin-binding protein type 1 has a distinctive lipocalin-like structure and is involved in the excretion of tributyltin in Japanese flounder, Paralichthys olivaceus, Aquatic Toxicology, 10.1016/j.aquatox.2008.08.019, 90, 4, 292-299, 2008.12, Tributyltin-binding protein type 1 (TBT-bp1) is a newly discovered protein that binds with TBT in the blood of the Japanese flounder, Paralichthys olivaceus. We determined the genomic sequence of TBT-bp1 and found that this protein has a conserved exon-intron structure that is common to the lipocalin protein family. The secondary and tertiary structures of TBT-bp1, predicted from amino acid sequence, included at least two α-helices and eight β-sheets that are conserved in all lipocalins and form a barrel structure that may bind with ligands. Analysis of the gene structure, secondary structure, and tertiary structure demonstrated that TBT-bp1 could be classified as a lipocalin. A homology search revealed the presence of TBT-bp1-like proteins in eight species of teleost. When flounder were injected intraperitoneally with TBT-d27 at 11.6 μg/fish, TBT-d27 was detected in the blood and in the skin mucus. The concentration of TBT-d27 in mucus was approximately 1/100 of that in the serum. Western blotting analysis revealed that TBT-bp1 was present in the skin mucus. These results suggest that TBT-bp1 in Japanese flounder binds with TBT and is excreted from the body via the mucus..
142. Shikata T, Yoshikawa S, Matsubara T, Tanoue W, Yamasaki Y, Shimasaki Y, Matsuyama Y, Oshima Y, Jenkinson IR, Honjo T. , Growth dyanmics of Heterosigma akashiwo (Raphidophyceae) in Hakata Bay, Japan., European Journal of Phycology , 43: 395-411, 2008.11.
143. Shikata T, Nagasoe S, Matsubara T, Yoshikawa S, Yamasaki Y, Shimasaki Y, Oshima Y, Jenkinson IR, Honjo T. , Factors influencing the initiation of blooms of the raphidophyte Heterosigma akashiwo and the diatom Skeletonema costatum in a port in Japan., Limnology and Oceanography , 53: 2503-2518, 2008.11.
144. Tomoyuki Shikata, Sou Nagasoe, Tadashi Matsubara, Souta Yoshikawa, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Oshima, Ian R. Jenkinson, Tsuneo Honjo, Factors influencing the initiation of blooms of the raphidophyte Heterosigma akashiwo and the diatom Skeletonema costatum in a port in Japan, Limnology and Oceanography, 10.4319/lo.2008.53.6.2503, 53, 6, 2503-2518, 2008.11, We investigated how environmental factors initiate Heterosigma akashiwo and Skeletonema costatum blooms from resting stages in bottom sediments in a shallow port over 2 yr. Using field-collected sediments, we also conducted laboratory experiments on how light intensity affects germination of resting stages and growth of the germinated cells. Both phytoplankton species bloomed only in summer, when water temperature and solar radiation were high enough for growth. All three blooms of H. akashiwo and the earliest bloom of S. costatum in a year occurred right after transmission of strong light (>200 μmol quanta m-2 s-1) to the bottom layer and a peak occurred in dissolved inorganic phosphorus (DIP). In the laboratory, resting stages of H. akashiwo and S. costatum germinated even in dim light (20 and 65 μmol quanta m-2 s-1, respectively), but germinated cells required stronger light of >130 and 280 μmol quanta m-2 s-1, respectively, for rapid growth. This value is much higher than the threshold for survival, and is higher than the half-saturating light intensity for growth of vegetative cells. Abundance of the resting stages of both species in the sediments rapidly increased during blooms and logarithmically decreased during nonbloom periods, suggesting that resting stages are continuously consumed. For both species, our results suggest that blooms initiate when transmission of sufficient light permits: first, germination of cells from the sediment; second, rapid growth of these germinated cells. Temperature and DIP must also exceed a facilitating threshold..
145. Tomoyuki Shikata, Souta Yoshikawa, Tadashi Matsubara, Wataru Tanoue, Yasuhiro Yamasaki, Yohei Shimasaki, Yukihiko Matsuyama, Yuji Oshima, Ian R. Jenkinson, Tsuneo Honjo, Growth dynamics of Heterosigma akashiwo (Raphidophyceae) in Hakata Bay, Japan, European Journal of Phycology, 10.1080/09670260801979295, 43, 4, 395-411, 2008.11, In Hakata Bay, Japan, from April to June 2006, Heterosigma akashiwo dynamics were investigated by daily to weekly sampling in relation to environmental parameters. To test how well the water in the samples supported H. akashiwo growth, bioassays of growth of a cultured strain of H. akashiwo were also conducted on these samples. In Hakozaki, a semi-enclosed fishing port, H. akashiwo had bloomed at almost all stations, one week after DIN and DIP concentrations increased by the end of May. Thereafter, H. akashiwo declined and fluctuated at low densities. The H. akashiwo population almost completely disappeared associated with a rapid decrease in salinity at the end of June. In the bioassays, addition of phosphate and nitrate often promoted H. akashiwo growth during the investigation, but 1 week before the H. akashiwo bloom, the growth rates in seawater samples without addition of these nutrients became close to those with nutrients. Addition of vitamins and metals barely affected growth rates during the investigation period. Moreover, even when some phytoplankton species also bloomed densely, H. akashiwo grew in the seawater samples at rates similar to that when phytoplankton abundance was low, indicating absence of significant allelopathic control by other phytoplankton. The present study shows that H. akashiwo growth is limited by N- and P-sources in this bay..
146. Nakayama K and Oshima Y., Adverse effects of tributyltin on reproduction of Japanese medaka, Oryzias latipes. , Coastal Marine Science. , 32: 1-8., 2008.08.
147. Tadashi Matsubara, Sou Nagasoe, Yasuhiro Yamasaki, Tomoyuki Shikata, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Inhibitory effects of centric diatoms on the growth of the dinoflagellate Akashiwo sanguinea, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.74.598, 74, 4, 598-606, 2008.07, Results of a four-year study on phytoplankton in Hakozaki Harbor, Hakata Bay, Japan indicated that Akashiwo sanguinea (Hirasaka) Hansen et Moestrup was the cause of frequent blooms during the late fall period when centric diatoms such as Skeletonema costatum and genus Chaetoceros declined. In laboratory experiments, the growth of A. sanguinea was found to be strongly inhibited in bi-algal cultures with S. costatum and Chaetoceros didymum, but just slightly with Asterionella japonica. Furthermore, when A. sanguinea was cultured in nitrogen and phosphorus enriched filtrates with media on which S. costatum and C. didymum had grown densely, the growth rate of A. sanguinea in the filtrates was significantly lower than that in fresh control medium. These results suggest that in spring and summer allelopathy of bloomed centric diatoms was an important factor that inhibited the growth of A. sanguinea but in the late fall when the cell density of these diatoms declined, A. sanguinea could form blooms..
148. Shikata T, Nagasoe S, Matsubara T, Yamasaki Y, Shimasaki Y, Oshima Y, Honjo T. , Encystment and excystment of Gymnodinium instriatum Freudenthal et al Lee. , Journal of Oceanography, 64: 355-365., 2008.06.
149. Tomoyuki Shikata, Sou Nagasoe, Tadashi Matsubara, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Oshima, Takuji Uchida, Ian R. Jenkinson, Tsuneo Honjo, Encystment and excystment of Gyrodinium instriatum Freudenthal et Lee, Journal of Oceanography, 10.1007/s10872-008-0028-y, 64, 3, 355-365, 2008.06, In the present study, we have investigated the conditions influencing encystment and excystment in the dinoflagellate Gyrodinium instriatum under laboratory conditions. We incubated G. instriatum in modified whole SWM-3 culture medium and in versions of modified SWM-3 from which NO3-, PO43-, NO3- + PO43-, or Si had been omitted and observed encystment. Percentage encystment was high in the media without N and without P, while the percentage encystment in the medium lacking both N and P was highest. Moreover, to investigate N or P concentration which induced the encystment, Gyrodinium instriatum was also incubated in media with different concentrations of inorganic N and P; the concentrations of NO2- + NO3- and PO43- were measured over time. The precursors of cysts appeared within 2 or 3 days of a decrease in NO2- + NO3- or PO43- concentration to values lower than 1 μM or 0.2 μM, respectively. When cysts produced in the laboratory were incubated, we observed excystment after 8-37 days, without a mandatory period of darkness or low temperature. We incubated cysts collected from nature at different temperatures or in the dark or light and observed excystments. Natural cysts excysted at temperatures from 10 to 30°C, in both light and dark, but excystment was delayed at low temperatures. These studies indicate that G. instriatum encysts in low N or P concentration and excysts over a wide temperature range, regardless of light conditions, after short dormancy periods..
150. Kang IJ, Yokota H, Oshima Y, Tsuruda Y, Shimasaki Y, and Honjo T. , The effects of methyltestosterone on the sexual development and reproduction of adult medaka (Oryzias latipes). , Aquatic Toxicology , 87: 37-46., 2008.04.
151. Ikjoon Kang, Hirofumi Yokota, Yuji Oshima, Yukinari Tsuruda, Yohei Shimasaki, Tsuneo Honjo, The effects of methyltestosterone on the sexual development and reproduction of adult medaka (Oryzias latipes), Aquatic Toxicology, 10.1016/j.aquatox.2008.01.010, 87, 1, 37-46, 2008.04, We examined the effects of methyltestosterone (MT) on the reproduction of medaka (Oryzias latipes). Six mating pairs of medaka were exposed for 3 weeks to MT at the measured concentrations of 22.5, 46.8, 88.1, 188, and 380 ng/L. The fecundity and fertility of paired medaka were significantly decreased in the 46.8, 88.1, 188, and 380 ng/L MT groups compared with those of controls. The gonadosomatic indices of female fish exposed to ≥46.8 ng/L were increased significantly. Gonadal histology showed degeneration of oocytes in the ovaries of fish in all MT treatment groups. Hepatic vitellogenin concentrations were significantly decreased in female fish treated with MT at 188 and 380 ng/L, and the hatchability and survival rate of the offspring were decreased in all MT treatment groups. These results clearly demonstrate that MT at ≥46.8 ng/L inhibited gonadal development and adversely affected the reproduction of medaka..
152. Nakayama K, Sei N, Oshima Y, Tashiro K, Shimasaki Y, Honjo T., Alteration of gene expression profiles in the brain of Japanese medaka (Oryzias latipes) exposed to KC-400 or PCB126. , Marine Pollution Bulletin , 2008.03.
153. Kei Nakayama, Naomi Sei, Yuji Oshima, Kosuke Tashiro, Yohei Shimasaki, Tsuneo Honjo, Alteration of gene expression profiles in the brain of Japanese medaka (Oryzias latipes) exposed to KC-400 or PCB126, Marine Pollution Bulletin, 10.1016/j.marpolbul.2008.02.020, 57, 6-12, 460-466, 2008.03, Polychlorinated biphenyls (PCBs) are known as neurotoxic chemicals and possibly alter animal behavior. We previously reported that PCB-exposure induced abnormal schooling behavior in Japanese medaka (Oryzias latipes). This abnormal behavior might be caused by the functional alteration of central or terminal nervous system. To understand the mechanism(s) of behavioral change by PCB-exposure, we analyzed the gene expression profiles in the brain of medaka exposed to 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) or a PCB mixture (Kanechlor-400: KC-400) using a cDNA microarray that we constructed. Twelve FLF-II strain medaka (six individuals per treatment) were dietary exposed to PCB126 (0.01 μg/g b.w./day) or KC-400 (1 μg/g b.w./day) for three weeks. For the control, six fish were fed a control diet. After the exposure period, fish were dissected, and the brain samples were collected. The samples from control fish were pooled and used as a common reference in the microarray experiment. Microarray data were normalized by the LOWESS method, and we screened the genes whose expression levels were altered more than 1.5-fold. Gene expression profiling showed 97 down-regulated and 379 up-regulated genes in the brain of medaka exposed to PCB126. KC-400 exposure suppressed 15 genes and induced 266 genes in medaka brain. Among these genes, the expression levels of 7 and 188 genes were commonly down- or up-regulated, respectively in both treatment groups. On the other hand, 31 gene expressions were significantly different between PCB126 and KC-400 treatment groups, and three out of 31 genes were received opposite effects. In addition, the microarray data showed that thyroid hormone-responsive genes were up-regulated by PCB-exposure, which may imply that PCBs or their metabolites mimic thyroid hormone effects in the brain of PCB-exposed medaka..
154. Oh SJ, Kim DI, Sajima T, Shimasaki Y, Matsuyama Y, Oshima Y, Honjo T, Yang HS., Effects of irradiance of various wavelengths from light-emitting diodes on the growth of the harmful dinoflagellate Heterocapsa circularisquama and the diatom Skeletonema costatum., Fisheries Science, 2008.02.
155. Shimasaki Y, Oshima Y, Inoue Y, Shibata H, Nakayama K, Inoue S, Imoto H, Kang IJ, Honjo T. , Distribution of tributyltin in tissues of mature Japanese whiting, Sillago japonica and their eggs. , Journal of Faculty of Agriculture Kyushu University, 53: 67-72., 2008.02.
156. Shikata T, Nagasoe S, Oh SJ, Matsubara T, Yamasaki Y, Shimasaki Y, Oshima Y, Honjo T. , Effects of down- and up-shocks from rapid changes of salinity on survival and growith of estuarine phytoplankters. , Journal of Faculty of Agriculture Kyushu University, 53: 81-87., 2008.02.
157. Yohei Shimasaki, Yuji Oshima, Yoshiyuki Inoue, Hisashi Shibata, Kei Nakayama, Suguru Inoue, Hisaya Imoto, Ik Joon Kang, Tsuneo Honjo, Distribution of tributyltin in tissues of mature Japanese whiting, Sillago japonica and their eggs, Journal of the Faculty of Agriculture, Kyushu University, 53, 1, 68-72, 2008.02, Tributyltin (TBT) has continued to pollute the coastal areas therein following global regulation for its use as an anti-fouling agent. The tissue dynamics of TBT in fish have been extensively documented, but few studies on maternal transfer of TBT have been performed. Previously, we reported that TBT was maternally transferred from parent fish to eggs. The present study examined the distribution of TBT in the tissues and spawned eggs of Japanese whiting, Sillago japonica, after dietary exposure to TBT. The percentage distribution of whole-body TBT in each tissue was estimated to be 50% in blood, 29% in muscle, 1.7% in liver, 0.4% in brain, 3.3% in ovary, and 0.47% in eggs spawned in a single day. Of the TBT in whole eggs, 28.8% was in the yolk and 13.5% in the oil droplet. However, the concentration of TBT in the oil droplet was calculated to be 43 times higher than that in the yolk. These results indicate that blood is an important tissue for the accumulation of TBT in fish and suggest that TBT is maternally transferred along with the egg components..
158. Tomoyuki Shikata, Sou Nagasoe, Seok Jin Oh, Tadashi Matsubara, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of down- and up-shocks from rapid changes of salinity on survival and growth of estuarine phytoplankters, Journal of the Faculty of Agriculture, Kyushu University, 53, 1, 81-87, 2008.02, In the laboratory, we investigated the effects of rapid changes of salinity on the survival and growth of 13 species of phytoplankton inhabiting an estuary where there are wide fluctuations in salinity. These phytoplankton were exposed to rapid decreases in salinity (down-shocks) from 32 to 5, 10, 15, or 20 psu, acclimatized to these lower salinities, and thereafter exposed to rapid increases (up-shocks) from the lower salinities to 32 psu. The phytoplankters tested proliferated in decreases and increases of salinity between 20 and 32 psu in a manner similar to controls (i.e. from 32 to 32 psu), but showed diagnostic responses such as a long lag-time before growth or mortality following drastic decreases or increases between 5-15 and 32 psu. The responses differed among phytoplankton species inhabiting the same estuary. Some flagellates formed morphologically abnormal cells after some treatments involving decreased salinity. The species-specific responses to drastic changes of salinity may contribute to the short-term succession of phytoplankton in estuaries..
159. Seok Jin Oh, Dae Il Kim, Takao Sajima, Yohei Shimasaki, Yukihiko Matsuyama, Yuji Oshima, Tsuneo Honjo, Han Soeb Yang, Effects of irradiance of various wavelengths from light-emitting diodes on the growth of the harmful dinoflagellate Heterocapsa circularisquama and the diatom Skeletonema costatum, Fisheries science, 10.1111/j.1444-2906.2007.01503.x, 74, 1, 137-145, 2008.02, We investigated the effects of specific light wavelengths from light-emitting diodes (LEDs) on the growth of the dinoflagellate Heterocapsa circularisquama, which kills bivalves, and the diatom Skeletonema costatum, which is an important food source for bivalves. Growth of H. circularisquama was obviously inhibited at 590 nm and a photon flux density less than 75 μmol quanta/m2/s. However, growth of S. costatum was not suppressed by irradiance from any LEDs tested from near-ultraviolet to near-infrared wavelengths at 75 μmol quanta/m2/s. The growth rate of H. circularisquama in an experimental treatment group with irradiance provided by both cool-white fluorescent lamps (12:12 h L : D cycle) and a 590-nm LED (continuous irradiance) was 0.43/day. In the control group with irradiance provided only by cool-white fluorescent lamps (12:12 h L : D cycle), the growth rate was 0.63/day, indicating that growth of H. circularisquama was suppressed by 590 nm (less than 75 μmol quanta/m2/s) irradiance from the LED and the continuous irradiance. The use of 590-nm LEDs in bivalve culture at irradiance levels less than 75 μmol quanta/m2/s might encourage the growth of the useful diatom S. costatum without stimulating growth of the harmful dinoflagellate H. circularisquama..
160. Hano T, Oshima Y, Kim SG, Satonne H, Ooba Y, Kitano T, Inoue S, Shimasaki Y, Honjo T., Tributlyltin causes abnormal development in embryo of medaka, Oryzias latipes., Chemosphere, 69: 927-933, 2007.10.
161. Tomoyuki Shikata, Sou Nagasoe, Tadashi Matsubara, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of temperature and light on cyst germination and germinated cell survival of the noxious raphidophyte Heterosigma akashiwo, Harmful Algae, 10.1016/j.hal.2007.02.008, 6, 5, 700-706, 2007.10, The effects of temperature and light on the germination of Heterosigma akashiwo cysts were examined using bottom sediments collected from Hakata Bay, Japan. In a suspension of mixed sediment and seawater in the temperature range of 5-30 °C, motile cells emerged within 3 weeks, but at ≤12 °C the cell numbers were markedly lower and the emergence of motile cells delayed. When suspension samples incubated at various temperatures were moved to 20 °C and incubated, only a few additional motile cells emerged. The number of motile cells germinated in the dark was significantly lower than under light conditions. When suspension samples incubated in the dark were exposed to light, only a few additional motile cells emerged. These results indicate that the initiation of germination in Heterosigma cysts suspended in seawater is not dependent on temperature and light conditions, although the speed of the germination process is affected by temperature, and cell survival just after germination is strongly affected by temperature and light..
162. Takeshi Hano, Yuji Oshima, Sang Gyoon Kim, Hina Satone, Yumi Oba, Takeshi Kitano, Suguru Inoue, Yohei Shimasaki, Tsuneo Honjo, Tributyltin causes abnormal development in embryos of medaka, Oryzias latipes, Chemosphere, 10.1016/j.chemosphere.2007.05.093, 69, 6, 927-933, 2007.10, We examined the effects of tributyltin (TBT) on embryonic development, hatching success and sexual differentiation in Japanese medaka (Oryzias latipes). Embryos (within 8 h after fertilization) were exposed to TBT in ovo via nanoinjection at concentrations of 0 (control), 0.16, 0.80, 3.96, 19.2 and 82.1 ng/egg. Embryonic survival, development and hatching were observed. Hatched fry were reared until 60 days when they sexually matured, and sexual differentiation was also examined by accordance of genetic and phenotypic sex, based on existence of DMY (a male determining gene in medaka) and secondary sex characteristics. As results, TBT caused a concentration-dependent mortality and impaired the embryonic development. However, no masculinization was detected at 60 dph medaka adults. Lowest observed effective concentration for inducing abnormal embryonic development was estimated to 0.16 ng/egg (ca. 160 ng/g egg)..
163. Oba Y, Shimasaki Y, Oshima Y, Satone H, Kitano T, Nakao M, Kawabata S, Honjo T., Purification and characterization of tributyltin binding protein type 2 from plasma of Japanese flounder, Paralichthys olivaceus., 2007.08.
164. Y. Yamasaki, S. Nagasoe, T. Matsubara, T. Shikata, Y. Shimasaki, Y. Oshima, T. Honjo, Growth inhibition and formation of morphologically abnormal cells of Akashiwo sanguinea (Hirasaka) G. Hansen et Moestrup by cell contact with Cochlodinium polykrikoides Margalef. , Marine Biology, 152 : 157-163, 2007.08.
165. Yumi Oba, Yohei Shimasaki, Yuji Oshima, Hina Satone, Takeshi Kitano, Miki Nakao, Shun-Ichiro Kawabata, Tsuneo Honjo, Purification and characterization of tributyltin-binding protein type 2 from plasma of Japanese flounder, Paralichthys olivaceus, Journal of biochemistry, 10.1093/jb/mvm119, 142, 2, 229-238, 2007.08, We used gel filtration chromatography, anion-exchange chromatography and polyacrylamide gel electrophoresis to purify tributyltin-binding protein type 2 (TBT-bp 2) from plasma of Japanese flounder (Paralichthys olivaceus) injected intraperitoneally with TBT (5.0mg/kg body weight). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the molecular mass of TBT-bp 2 was approximately 48kDa, and isoelectric focusing-polyacrylamide gel electrophoresis indicated that the isoelectric point was approximately 3.0. TBT-bp 2 contained 40% N-glycan. The complete cDNA nucleotide sequence and the genome sequence of TBT-bp 2 were determined by means of rapid amplification of cDNA ends of liver tissue of Japanese flounder and a genome-walking technique, respectively. The 216 amino acid sequence of TBT-bp 2 showed 47% identity to the sequences of puffer fish (Takifugu pardalis) saxitoxin- and tetrodotoxin-binding protein but only 27% similarity to the sequence of TBT-bp 1. Analysis of the motif sequence of the amino acid sequence and the structure of the gene encoding TBT-bp 2 suggested that this protein belongs to the lipocalin superfamily..
166. Tomoyuki Shikata, Sou Nagasoe, Tadashi Matsubara, Yasuhiro Yamasaki, Yohei Shimasaki, Yuji Ohshima, and Tsuneo Honjo, Effects of temperature and light on cyst germination and ger-minated cell survival of the noxious raphidophyteHeterosigma akashiwo. , Harmful Algae, 6: 700-706, 2007.07.
167. Dae Il Kim, Tadashi Matsubara, Seok Jin Oh, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of nitrogen and phosphorus sources on the utilization and growth kinetics of the harmful dinoflagellate Cochlodinium polykrikoides isolated from Yatsushiro Sea, Japan, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.73.711, 73, 4, 711-717, 2007.07, The effects of various inorganic and organic nitrogen (N) and phosphorus (P) sources on the utilization and growth kinetics of the harmful dinoflagellate Cochlodinium polykrikoides Margalef, which was isolated from the Yatsushiro Sea of Japan, were experimentally investigated. C. polykrikoides was able to grow actively with inorganic nitrogen compounds and to grow at a slower rate on organic nitrogen compounds, urea and amino acid glycine, as N-sources. On the other hand, this organism was able to effectively utilize a variety of both inorganic and organic phosphorus compounds as P sources. Specific maximum growth rate (μ′m) and minimum cell quota (Q0), which were obtained by semi-continuous growth experiments, were 0.48 day-1 and 5.25 pmol cell-1 under N-limited steady-state conditions, and 0.54 day-1 and 0.37pmol cell-1 under P-limited steady-state conditions. Based on the physiological characteristics obtained in the present study, C. polykrikoides may have advantages for species competition..
168. Yasuhiro Yamasaki, Sou Nagasoe, Tadashi Matsubara, Tomoyuki Shikata, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Growth inhibition and formation of morphologically abnormal cells of Akashiwo sanguinea (Hirasaka) G. Hansen et Moestrup by cell contact with Cochlodinium polykrikoides Margalef, Marine Biology, 10.1007/s00227-007-0671-7, 152, 1, 157-163, 2007.07, We investigated the growth interaction between Cochlodinium polykrikoides and Akashiwo sanguinea using bi-algal cultures. When cultured together, morphologically abnormal cells of A. sanguinea appeared and the growth of A. sanguinea notably decreased. When C. polykrikoides and A. sanguinea were cultured separately in inner and outer wells separated by a membrane with a pore size of 3 μm, neither species showed suppressed growth and no morphologically abnormal cells of A. sanguinea were observed. Furthermore, filtrates from C. polykrikoides cultures did not affect the cell morphology or the growth of A. sanguinea. When the abnormal cells of A. sanguinea were transferred from bi-algal cultures into fresh medium and cultured as a mono-algal culture, cells recovered their normal morphology and multiplied. Therefore, the growth inhibition and formation of morphologically abnormal cells of A. sanguinea would be induced by constant cell contact with C. polykrikoides..
169. Yasuhiro Yamasaki, Sou Nagasoe, Tadashi Matsubara, Tomoyuki Shikata, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Allelopathic interactions between the bacillariophyte Skeletonema costatum and the raphidophyte Heterosigma akashiwo, Marine Ecology Progress Series, 10.3354/meps339083, 339, 83-92, 2007.06, We investigated growth interactions between Skeletonema costatum (Greville) Cleve and Heterosigma akashiwo (Hada) Hada ex Hara et Chihara using bi-algal cultures under axenic conditions. When inoculated at high cell densities, growth of both species was coincidentally suppressed. In other combinations of inoculation density, the species first reaching stationary phase substantially reduced maximum cell densities of the other species. When cultured together under conditions without cell contact, growth of S. costatum and H. akashiwo were both suppressed. Furthermore, despite re-enrichment with nutrients, filtrates from dense cultures of S. costatum and H. akashiwo reciprocally reduced their maximum cell densities. In additional experiments, growth of Chaetoceros muelleri was also suppressed with filtrates from the above cultures, but growth of Prorocentrum minimum was not. Therefore, growth interactions between these species strongly suggest the involvement of allelopathic substances secreted by both species. Finally, growth and interaction of S. costatum and H. akashiwo in bi-algal cultures were simulated using a mathematical model. This model indicated that S. costatum and H. akashiwo steadily approach a stable equilibrium point of about 3.4 × 105 cells ml-1 and 4.8 × 105 cells ml-1, respectively, when the 2 species coexist..
170. Kazutoshi Saeki, Akiko Nabeshima, Takashi Kunito, Yuji Oshima, The stability of butyltin compounds in a dredged heavily-contaminated sediment, Chemosphere, 10.1016/j.chemosphere.2007.01.074, 68, 6, 1114-1119, 2007.06, A treatment process for marine sediment heavily contaminated with tributyltin (TBT) was designed that included dehydrating, sunlight drying and dumping processes. The time course in butyltin (BTs) compounds, TBT, dibutyltin (DBT) and monobutyltin concentrations were investigated in the sediment treated under various conditions (light (UV, sunlight and light exclusion), moisture (air-drying and water saturation) and wetting and drying cycles). Significant changes in all the BT compound concentrations with time were not found regardless of the sediment conditions for light and moisture. The results indicated the high stabilities of TBT and DBT in the sediments versus light and moisture condition changes, probably taking place in the treatment process. It is also estimated that the BTs in the sediment are resistant to photo-degradation and biochemical degradation and their half lives are relatively long. In contrast, the decreases in the TBT and DBT were observed during the wetting and drying cycle treatment for the water saturated sediment both during exposure to sunlight and under a dark condition. This result suggested the hypothesis that the TBT degradation could be accelerated by the high microbial activity induced by the moisture changing treatments..
171. Saeki K., Nabeshima A., Kunito T., Oshima Y., The stability of butyltin compounds in a dredged heavily-contaminated sediment. , Chemosphere, 68, 1114-1119., 2007.05.
172. Y. Yamasaki, S. Nagasoe, T. Matsubara, T. Shikata, Y. Shimasaki, Y. Oshima and T. Honjo, Allelopathic interactions between the bacillariophyte Skeletonema costatum (Greville) Cleve and the raphidophyte Heterosigma akashiwo (Hada) Hada ex Hara et Chihara, Marine Ecology Progress Series, 339 : 83-92, 2007.04.
173. Tadashi Matsubara, Sou Nagasoe, Yasuhiro Yamasaki, Tomoyuki Shikata, Yohei Shimasaki, Yuji Oshima, Tsuneo Honjo, Effects of temperature, salinity, and irradiance on the growth of the dinoflagellate Akashiwo sanguinea, Journal of Experimental Marine Biology and Ecology, 10.1016/j.jembe.2006.09.013, 342, 2, 226-230, 2007.04, The effects of temperature, salinity, and irradiance on the growth of the dinoflagellate Akashiwo sanguinea were examined in the laboratory. The irradiance at the light compensation point (I0) was 14.40 μmol m- 2 s- 1 and the irradiance at growth saturation (Is) was 114 μmol m- 2 s- 1. We exposed A. sanguinea to 48 combinations of temperature (5-30 °C) and salinity (5-40) under saturating irradiance; it exhibited its maximum growth rate of 1.13 divisions/day at a combination of 25 °C and salinity of 20. A. sanguinea was able to grow at temperatures from 10 to 30 °C and salinities from 10 to 40. This study revealed that A. sanguinea was a eurythermal and euryhaline organism; in Japan it should have formed blooms in early summer, when salinity was relatively low. In addition, it was noteworthy that A. sanguinea had markedly cold-durability, retaining the motile form of vegetative cells for more than 50 days at 5 °C and at salinities of 25-30..
174. Kei Nakayama, Yuji Oshima, Tetsuya Tachibana, Mitsuhiro Furuse, Tsuneo Honjo, Alteration of monoamine concentrations in the brain of medaka, Oryzias latipes, exposed to tributyltin, Environmental Toxicology, 10.1002/tox.20233, 22, 1, 53-57, 2007.03, We measured the concentrations of monoamines in the brain of Japanese medaka, Oryzias latipes, exposed to tributyltin (TBT). Fish were exposed to 0, 1, 5, 25, or 125 μg g-1 of TBT via the diet for 21 days. After the administration period, six males and six females in each treatment group were dissected and their brains were collected. The following monoamines were analyzed: dopamine (DA), norepinephrine (NE), epinephrine (E), and 5-hydroxytryptamine (5-HT). The metabolites of DA, 3,4-dihydroxyphenylacetic acid and homovanilic acid, and the metabolite of 5-HT, 5-hydroxyindolacetic acid were also analyzed. The concentration of DA in the brain of male medaka and the concentrations of 5-HT and NE in the female brains were significantly decreased by exposure to 125 μg TBT g-1. The concentrations of 5-HT and NE in males and of DA in females were slightly decreased by 125 μg g -1 of TBT, although the differences were not statistically significant. The present study demonstrates that TBT alters monoamine concentrations in the brain of medaka..
175. Takeshi Hano, Yuji Oshima, Masato Kinoshita, Minoru Tanaka, Noriko Mishima, Tetsuji Ohyama, Takashi Yanagawa, Yuko Wakamatsu, Kenjiro Ozato, Tsuneo Honjo, Quantitative bioimaging analysis of gonads in olvas-GFP/ST-II YI medaka (transgenic Oryzias latipes) exposed to ethinylestradiol, Environmental Science and Technology, 10.1021/es0620134, 41, 4, 1473-1479, 2007.02, This study investigates the adverse and persistent effects of ethinylestradiol (EE2) on mature gonads of transgenic olvas-GFP/ST II-YI medaka (Oryzias latipes). The measurement of gonadal size calculating the GFP-fluorescent area was used as a technique that enabled monitoring gonads in living specimens by GFP fluorescence. First, mature medaka were exposed to EE2 (47.8-522 ng/L) for 4 weeks. The gonads showed a significant reduction of the GFP-fluorescent area and Gonadosomatic Index in males exposed to EE2 at >216 ng/L and females exposed at 522 ng/L. Histologically, males at all treatments exhibited testis-ova and additionally, high connective tissue prevalence at ≥216 ng/L. Next, mature male medaka were exposed to EE2 (43.7-473 ng/L) for 3 weeks and allowed to depurate for 6 weeks, to investigate persistent effects of EE2. Continuous gonad observation showed that GFP began to decline 3 weeks after initial exposure to ≥215 ng/L. After depuration, the gonad's fluorescent areas gradually recovered, with no statistical difference at the end of the depuration period; normal spermatogenesis was present in these individuals. Alterations in GFP fluorescence clearly indicate the condition of the gonad in transgenic medaka and this strain showed a facilitated screening fish model to detect the adverse effects on the gonad by estrogenic chemicals..
176. S. Inoue, Y. Oshima, S. Abe, R. Wu, K. Nakayama, T. Honjo, Effects of tributyltin on energy metabolism of pen shell (Atrina pectinata japonica), Chemosphere, , 66, 1226-1229, 2007.01.
177. K. Nakayama, Y. Oshima, T. Tachibana, M. Furuse, T. Honjo, Alteration of monoamine concentrations in the brain of medaka, Oryzias latipes, exposed to tributyltin. , , Environmental Toxicology, , 22,53-57, 2007.01.
178. Hano, T., Y. Oshima, M. Kinoshita, M. Tanaka, N. Mishima, T. Ohyama, T. Yanagawa, Y. Wakamatsu, K. Ozato, T. Honjo., Quantitative bioimaging analysis of gonads in olvas-GFP/ST-II YI medaka (transgenic Oryzias latipes) exposed to ethinylestradiol., Environ Sci Tech, 41, 1473-1479., 2007.01.
179. Takagi, S., Tomonaga, S., Ito, S., Oshima, Y., Honjo, T. and Furuse, M., Effect of in utero TPTCL exposure on the learned behavior of mice after birth., JAAR, 31, No. 1.( in printing), 2007.01.
180. Inoue, S., Y. Oshima, H. Usuki, M. Hamaguchi, Y. Hanamura, N. Kai, Y. Shimasaki, T. Honjo. , Effect of tributyltin on veliger larvae of the Manila clam, Ruditapes philippinarum, , Chemosphere, 66, 1353-1357, 2007.01.
181. Suguru Inoue, Yuji Oshima, Hironori Usuki, Masami Hamaguchi, Yukio Hanamura, Norihisa Kai, Yohei Shimasaki, Tsuneo Honjo, Effect of tributyltin on veliger larvae of the Manila clam, Ruditapes philippinarum, Chemosphere, 10.1016/j.chemosphere.2006.06.052, 66, 7, 1353-1357, 2007.01, We investigated the effects of waterborne and maternal exposure to tributyltin (TBT) on veliger larvae of the Manila clam, Ruditapes philippinarum. In a waterborne exposure test, veliger larvae (D-larvae stage: 24 h after fertilization) were exposed to TBT at measured concentrations of <0.01 (control), 0.055, 0.130, 0.340, and 0.600 μg/l for 13 d. The percentage of normal veliger larvae (the ratio of normal veliger larvae to all larvae) decreased significantly in all TBT treatment groups compared with that in the control group. In a maternal exposure test, 100 clams were exposed to TBT at measured concentrations of <0.01 (control), 0.061, and 0.310 μg/l at 20-22 °C for 3 weeks, and the percentage of normal veliger larvae assessed for 13 d. No maternal effects on veliger larvae from TBT were observed in TBT treatment groups as compared with the control group. These results demonstrate that waterborne TBT affects Manila clam veliger larvae, and indicates that TBT may have reduced Manila clam populations by preventing the development and survival of veliger larvae..
182. Sayuri Takagi, Shozo Tomonaga, Sei Ito, Yuji Oshima, Tsuneo Honjo, Mitsuhiro Furuse, Effects of in utero tptcl exposure on the learned behaviors of mice after birth, Journal of Applied Animal Research, 10.1080/09712119.2007.9706621, 31, 1, 13-20, 2007.01, The open field test and the elevated plus-maze test were applied to investigate the effects of in utero triphenyltin chloride (TPTCL) exposure on learned behavior in ICR strain mice. During pregnancy mice (8-weeks-old) received daily oral administration of vehicle (corn oil) or TPTCL (0.9 and 9 mg I kg) for a period of up to 18 days. Plasma sex hormone concentrations, body weight and organ weights were not significantly changed and no external malformations were noted after TPTCL exposure in either dams or pups. However, a decrease in the number of animals completing pregnancy and the number of dams rearing pups normally was observed in the 9 mg I kg TPTCL group. No behavioral effects of TPTCL treatment were observed in pups or dams in the two tests employed. Measurable levels of TPTCL were found in the brains of dams in the TPTCL dosage group, but not in the brains of their pups. These results indicated that the TPTCL dosages and treatment period used did not influence metabolism and / or learned behaviors in mice. However the possibility is suggested that TPTCL may have adverse effects on normal pregnancy and maternal behavior..
183. Suguru Inoue, Yuji Oshima, Shin ichiro Abe, Rudolf S S Wu, Norihisa Kai, Tsuneo Honjo, Effects of tributyltin on the energy metabolism of pen shell (Atrina pectinata japonica), Chemosphere, 10.1016/j.chemosphere.2006.07.041, 66, 7, 1226-1229, 2007.01, We examined the effects of tributyltin (TBT) on aerobic and anaerobic energy metabolism of pen shell (Atrina pectinata japonica). We exposed pen shells to TBT at nominal concentrations of 0 (control) and 1.0 μg/l for 72 h under aerobic condition. At the end of the exposure, half of the pen shells in each treatment were wrapped in plastic wrap to simulate exposure to hypoxia and held at 25 °C for another 12 h. The concentrations of the products of energy metabolism, namely lactate, pyruvate, fumarate and succinate, in adductor muscle were measured. The exposure to TBT under aerobic condition significantly elevated lactate, pyruvate and fumarate concentrations (p < 0.001). After subsequent exposure to anaerobic condition, the mean concentration of succinate in the TBT treatment group was 64% of that in the control group, but there were no significant differences. Our results suggest that the energy metabolism of pen shell is disrupted by exposure to TBT..
184. Ikjoon Kang, Takeshi Hano, Yuji Oshima, Hirofumi Yokota, Yukinari Tsuruda, Yohei Shimasaki, Tsuneo Honjo, Anti-androgen flutamide affects gonadal development and reproduction in medaka (Oryzias latipes), Marine Environmental Research, 10.1016/j.marenvres.2006.04.065, 62, SUPPL. 1, 2006.06, The effects of an anti-androgenic chemical on the reproduction of medaka (Oryzias latipes) were examined. Six mating pairs of medaka were exposed to flutamide (FLU) at measured concentrations of 0.101, 0.202, 0.397, 0.787, or 1.56 mg/L for 3 weeks. During the exposure period, one female died in the 1.56-mg/L treatment group, but no lesions or pathological abnormalities were observed. The fecundity and fertility of paired medaka were significantly decreased at 1.56 mg/L compared with those of the controls. Histological examination showed intersex gonads (testis-ova) in males exposed to FLU at 0.202, 0.397, and 0.787 mg/L. However, concentrations of hepatic vitellogenin (Vtg) in both sexes were not statistically different from those in the controls. These results demonstrate that FLU affected gonadal development in male medaka and reproductive capacity in paired medaka. This is the first report of testis-ova in male medaka exposed to FLU..
185. Yohei Shimasaki, Yuji Oshima, Suguru Inoue, Yoshiyuki Inoue, Ikjoon Kang, Kei Nakayama, Hisaya Imoto, Tsuneo Honjo, Effect of tributyltin on reproduction in Japanese whiting, Sillago japonica, Marine Environmental Research, 10.1016/j.marenvres.2006.04.030, 62, SUPPL. 1, 2006.06, We examined the effect of tributyltin (TBT) on reproduction in the Japanese whiting, Sillago japonica. Mature fish were placed in indoor 500-L polyethylene tanks (five males and three females per tank) with a flow-through system and received dietary exposure to tributyltin oxide at concentrations of 2, 20, or 200 μg/g for 30 days during the active spawning period. Eggs spawned from the fish were collected daily, and the floating egg rate, larval deformity, hatchability, and viable hatch were monitored. TBT concentration in eggs of 200-μg/g group ranged from 85.0 to 159.6 ng/g in the evaluation period (days 5-30). In this period, the floating egg rate (83.2%), viable hatchability (82.2%), and total number of viable larvae (422,000 larvae per 100 g of female) were all significantly decreased in the 200-μg/g group compared with the control group (93.0%, 91.9%, and 709,000 larvae, respectively). The rate of deformity (2.6%) in the 200-μg/g group was about three times that in the control group (0.8%), although this difference was not significant. From these results, the lowest observed effect concentration of TBT in eggs on reproduction in Japanese whiting was estimated to be less than 159.6 ng/g-eggs..
186. Suguru Inoue, Yuji Oshima, Hironori Usuki, Masami Hamaguchi, Yukio Hanamura, Norihisa Kai, Yohei Shimasaki, Tsuneo Honjo, Effects of tributyltin maternal and/or waterborne exposure on the embryonic development of the Manila clam, Ruditapes philippinarum, Chemosphere, 10.1016/j.chemosphere.2005.07.047, 63, 5, 881-888, 2006.05, We examined the effect of tributyltin (TBT) on embryonic development of the Manila clam, Ruditapes philippinarum. In a maternal exposure test, 100 clams were exposed to TBT at measured concentrations of <0.01 (control), 0.061, 0.310, or 0.350 μg/l at 20-22 °C for 3 weeks, and the embryo developmental success (the ratio of normal D-larvae to all larvae) was measured. There was a significant negative correlation between embryo developmental success and TBT concentration in the female Manila clams (p < 0.001). These results indicated that TBT accumulated in the female clam decreased embryo developmental success. In a waterborne exposure test, fertilized eggs (4 h after fertilization) were exposed to TBT at measured concentrations of <0.01 (control), 0.062, 0.140, 0.320, or 0.640 μg/l for 23 h. Embryo developmental success was also significantly decreased in all TBT treatment groups compared with that in the control group. TBT accumulated in female adults and waterborne TBT clearly inhibit reproductive success of the clam..
187. Sou Nagasoe, Dae-Il Kim, Yohei Shimasaki, Yuji Oshima, Mineo Yamaguchi and Tsuneo Honjo, Effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee ,, Harmful Algae, Volume 5, Issue 1, 20-25, 2006.04.
188. Kang IJ, Hano T, Oshima Y, Yokota H, Tsuruda Y, Shimasaki Y, Honjo T., Anti-androgen flutamide affects gonadal development and reproduction in medaka (Oryzias latipes)., Mar Env Res., 62 Suppl 1:S253-7, 2006.04.
189. Shimasaki Y, Oshima Y, Inoue S, Inoue Y, Kang I J, Nakayama K, Imoto H and Honjo H., Effect of tributyltin on reproduction in Japanese whiting, Sillago japonica., Mar Env Res, 62 Suppl 1:S245-8, 2006.04.
190. Inoue S, Oshima Y, Usuki H, Hamaguchi M, Hanamura Y, Kai N, Shimasaki Y, Honjo T., Effects of tributyltin maternal and/or waterborne exposure on the embryonic development of the Manila clam, Ruditapes philippinarum, Chemosphere, 63,881-888, 2006.04.
191. S. Nagasoe, S. Toda, Y. Shimasaki, Y. Oshima, T. Uchida, T. Honjo, Growth inhibition of Gyrodinium instriatum (Dinophyceae) by Skeletonema costatum (Bacillariophyceae), , African Journal of Marine Science, 28, 325-329, 2006.01.
192. Sou Nagasoe, Dae Il Kim, Yohei Shimasaki, Yuji Oshima, Mineo Yamaguchi, Tsuneo Honjo, Effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee, Harmful Algae, 10.1016/j.hal.2005.06.001, 5, 1, 20-25, 2006.01, The effects of temperature, salinity and irradiance on the growth of the red tide dinoflagellate Gyrodinium instriatum Freudenthal et Lee were examined in the laboratory. Exposed to 45 different combinations of temperature (10-30°C) and salinity (0-40) under saturating irradiance, G. instriatum exhibited its maximum growth rate of 0.7 divisions/day at a combination of 25°C and a salinity of 30. Optimum growth rates (>0.5 divisions/day) were observed at temperatures ranging from 20 to 30°C and at salinities from 10 to 35. The organism could not grow at ≤10°C. In addition, G. instriatum burst at a salinity of 0 at all temperatures, but grew at a salinity of 5 at temperatures between 20 and 25°C. It is noteworthy that G. instriatum is a euryhaline organism that can live under extremely low salinity. Factorial analysis revealed that the contributions of temperature and salinity to its growth of the organism were almost equal. The irradiance at the light compensation point (I0) was 10.6 μmol/(m2 s) and the saturated irradiance for growth (Is) was 70 μmol/(m2 s), which was lower than Is for several other harmful dinoflagellates (90-110 μmol/(m2 s))..
193. S. Nagasoe, S. Toda, Yohei Shimasaki, Yuji Oshima, T. Uchida, T. Honjo, Growth inhibition of Gyrodinium instriatum (Dinophyceae) by Skeletonema costatum (Bacillariophyceae), African Journal of Marine Science, 10.2989/18142320609504171, 28, 2, 325-329, 2006.01, Interactions between the red tide-forming dinoflagellate Gyrodinium instriatum Freudenthl et Lee and the diatom Skeletonema costatum (Greville) Cleve were investigated in bialgal cultures. The growth rates and maximum cell densities of G. instriatum decreased dramatically in cultures containing S. costatum. In addition, morphologically abnormal cells of G. instriatum were observed in these cultures, and many cells lost their motility. Conversely, the growth of S. costatum was generally not influenced by the presence of G. instriatum, although small etiolated cells of S. costatum were occasionally observed when the initial cell density of G. instriatum was high. The growth of G. instriatum and S. costatum in the bialgal cultures was simulated using a mathematical model. This interactive model indicated that G. instriatum and S. costatum steadily approach a stable equilibrium point of about 5 × 10 3 cells ml-1 and 12 × 105 cells ml -1 respectively, when the two species coexist..
194. Dae-Il Kim, Y Matsuyama, S Nagasoe, M Yamaguchi, Yang-Ho Yoon, Y Oshima, N Imada, T Honjo., Effects of temperature, salinity and irradiance on the growth of the harmful red tide dinoflagellate Cochlodinium polykrikoides Margalef (Dinophyceas)., J Plankton Res, 10.1093/plankt/fbh001, 26, 1, 61-66, 26, 61-66., 2005.01.
195. Nakayama K, Oshima Y, Hiramatsu, Shimasaki Y, and Honjo T., Effects of polychlorinated biphenyls on the schooling behavior of Japanese medaka, Oryzias latipes., Environ Toxicol Chem, 10.1897/04-518R2.1, 24, 10, 2588-2593, 24: 2588-2593, 2005.01.
196. Hiramatsu K, Oshima Y, Inoue S, Shikasho S, Numerical modeling of environmental behavior and fate of tributyltin in a semi-closed bay. (2005) ., Paddy Water Environ, 10.1007/s10333-005-0003-9, 3, 2, 79-92, 3: 79 - 92, 2005.01.
197. Inoue S, Abe S, Oshima Y, Kai N, Honjo T., Tributyltin contamination of the bivalves in coastal areas around northern kyushu, Japan., Environmental Toxicology, 10.1002/tox.20177, 21, 3, 244-249, 21:244-249, 2005.01.
198. Oshima Y, Koyama J, Nakayama K, Inoue Y, Shimasaki Y, Inoue S and Honjo T., Use of hepatic CYP1A1 activity in Japanese flounder to monitor oil dispersed from the Nakhodka spill, Jpn J Environ Toxicol, 7:123-129, 2005.01.
199. Oshima Y, Takeda T, Katayama S, Inoue Y, Inoue S, Nakayama K, Shimasaki Y, and Honjo T., Relationship between temperature and pharmacokinetic parameters of florfenicol in carp (Cyprinus carpio), Jpn J Environ Toxicol, 7:61-68, 2005.01.
200. Takeshi Hano, Yuji Oshima, Toshiaki Oe, Masato Kinoshita, Minoru Tanaka, Yuko Wakamatsu, Kenjiro Ozato, Tsuneo Honjo, Quantitative bio-imaging analysis for evaluation of sexual differentiation in germ cells of olvas-GFP/ST-II YI medaka (Oryzias latipes) nanoinjected in ovo with ethinylestradiol, Environmental Toxicology and Chemistry, 10.1897/03-610.1, 24, 1, 70-77, 2005.01, We examined the effects on sexual differentiation of nanoinjecting ethinylestradiol (EE2) into embryos of olvas-GFP/ST-II YI medaka (Oryzias latipes). This strain contains the green fluorescent protein (GFP) gene fused to the regulatory region of the medaka vasa gene, and germ-cell-specific expression of GFP can be visualized in living (transparent) individuals. The number of germ cells in untreated genotypic females (XX) was approximately 10-fold that in untreated genotypic males (XY) at 10 d posthatch (dph). Germ cell proliferation was prevented in XX females that developed from embryos nanoinjected with 0.5, 2.5, or 5.0 ng of EE2. Some 10-dph XY males from embryos injected with 0.5 ng or more of EE2 showed a larger fluorescent area and more germ cells than those of pooled control groups. Males and females from embryos injected with 5.0 ng of EE2 had no significant difference in germ cell number or fluorescent area. Thus, EE 2 injection into embryos caused abnormal gonadal development in both sexes. Observations of external secondary sex characteristics and histological examination of adult gonads showed complete sex reversal in some males after 0.5-, 2.5-, and 5.0-ng treatments but no changes in XX females after any treatment. Thus, quantitative bioimaging can aid in evaluating the effects of endocrine-disrupting chemicals on fish within 10 dph..
201. Kei Nakayama, Yuji Oshima, Tomomi Yamaguchi, Yukinari Tsuruda, Ik Joon Kang, Makito Kobayashi, Nobuyoshi Imada, Tsuneo Honjo, Fertilization success and sexual behavior in male medaka, Oryzias latipes, exposed to tributyltin, Chemosphere, 10.1016/j.chemosphere.2003.11.050, 55, 10, 1331-1337, 2004.06, We evaluated the effects of tributyltin (TBT), polychlorinated biphenyls (PCBs), and a mixture of TBT and PCBs on reproduction, gonadal histology, and sexual behavior in Japanese medaka (Oryzias latipes). We administered TBT (1 μgg-1 body weight [b.w.] daily), PCBs (1 μgg-1 b.w. daily), or both to medaka for 3 weeks. We assessed reproductive success during week 3 and the sexual behavior of male medaka after the exposure period. Fertilization success was significantly decreased in groups that received TBT. The profiles of fertility developed a bimodal distribution in the TBT and TBT+PCBs groups, and the numbers of males that performed "following" and "dancing" were significantly decreased in the TBT+PCBs group. The frequency of "dancing" also decreased after treatment with TBT, whereas fish that received PCBs only showed no difference in sexual behavior. Testes that had oocytes showed normal spermatogenesis, even though two of the five males treated with TBT+PCBs had some indication of testis-ova, which did not occur in any other group. Our results indicate that TBT, but not PCBs, affects sexual behavior and reproduction in medaka..
202. Suguru Inoue, Yuji Oshima, Kiyohito Nagai, Takashi Yamamoto, Jyoji Go, Norihisa Kai, Tsuneo Honjo, Effect of maternal exposure to tributyltin on reproduction of the pearl oyster (Pinctada fucata martensii), Environmental Toxicology and Chemistry, 10.1897/03-265, 23, 5, 1276-1281, 2004.05, We examined the effect of tributyltin (TBT) on reproduction of the pearl oyster (Pinctadafucata martensii). In a maternal exposure test, five female pearl oysters were exposed to TBT at measured concentrations of 0 (control), 0.092, or 0.191 μg/L at 25°C for one week, and the embryo developmental success (the ratio of normal D-larvae to all larvae) was measured. The embryo developmental success was significantly decreased in the 0.191-μg/L treatment group (65.5%) compared to that in the control group (82.5%; p = 0.031). Concentrations of TBT in the ovary reached 0.088 μg/g in the 0.191-μg/L treatment group. In a waterborne exposure test, inseminated eggs were exposed to TBT at measured concentrations of 0 (control), 0.020, 0.045, 0.091, 0.192, or 0.374 μg/L for 24 h. The embryo developmental success also was significantly decreased in the 0.192-μg/L treatment group (78.3%; p = 0.020) and no development at all was observed in the 0.374-μg/L treatment group compared with that in the control group (95.4%). These results clearly demonstrate that TBT accumulating in the bodies of bivalves has the potential to inhibit reproduction..
203. Kei Nakayama, Yuji Oshima, Kazuaki Hiramatsu, Tsuneo Honjo, Alteration of general behavior of male medaka, Oryzias latipes, exposed to tributyltin and/or polychlorinated biphenyls, Journal of the Faculty of Agriculture, Kyushu University, 49, 1, 85-92, 2004.02, We examined the general behavior of male Japanese medaka, Oryzias latipes, after exposed to tributyltin (TBT), polychlorinated biphenyls (PCBs), or a mixture of these chemicals at a concentration of 1 μg/g body weight daily for 3 weeks. We analyzed swimming velocity as an indicator of acute toxicity and counted the frequencies of straight swimming and swimming in circles. We also calculated the entropy of the positions of the fish within the experimental chamber. Neither TBT nor PCBs nor their mixture affected the swimming velocity, suggesting that there were no acute toxic effects. However, PCBs exposure increased the frequencies of both straight and circular swimming, suggesting hyperactivity. TBT increased the positional entropy value. Both TBT and PCBs affect the general behavior of mature male medaka, although exposure to the 2 chemicals together has no significant additive behavioral effect..
204. Inoue S, Oshima Y, Nagai K, Yamamoto T, Go J, Hiramatsu J, Okada M, Imada N and Honjo T, Maternal effect of tributyltin on reproduction of pearl oyster, Pinctada fucata martensii, Environ Toxicol Chem, 23, 1276-1281, 2004.01.
205. Nakayama K, Oshima Y, Yamaguchi T, Tsuruda Y, Kang IJ, Kobayashi M, Imada N, Honjo T, Fertilization success and sexual behavior in male medaka, Oryzias latipes, exposed to tributyltin, Chemospheres, 10.1016/j.chemoshere.2003.11.050, 55, 10, 1331-1337, 55. 1331-1337, 2004.01.
206. Omura M, Shimasaki Y, Oshima Y, Nakayama K, Kubo K, Saou S, Ogata R, Hirata M, Inoue N., Distribution of tributyltin, dibutyltin and monobutyltin in the liver, brain and dat of rats: two-generation toxicity study of tributyltin chloride, Environ Sci, 11, 123-132, 2004.01.
207. Nakayama K, Oshima Y, Hiramatsu, K and Honjyo T., Alteration of general behavior of male medaka, Oryzias latipes, exposed to tributyltin and/or polychlorinated biphenyls., J. Fac. Agr. Kyshu Univ.,, 49, 1, 85-92, 49(1), 85-92, 2004.01.
208. Hano T, Oshima Y, Oe T, Kinoshita M, Tanaka M, Wakamatsu Y, Ozato K, Honjo T., A quantitative bioimaging analysis in the evaluation of sexual differentiation on germ cells of olvas-GFP/ST II-YI medaka, Oryzias latipes, nanoinjected with ethinyl estradiol., Environ Toxicol Chem, 24:70-77, 2004.01.
209. Nakayama K, Oshima Y, Nagafuchi K, Hano T, Shimasaki Y, and Honjo T., Early life stage toxicity in offspring from exposed parent medaka, Oryzias latipes, to mixtures of tributyltin and polychlorinated biphenyls., Environ Toxicol Chem (accepted), 10.1897/04-157R.1, 24, 3, 591-596, 24, 591?596, 2004.01.
210. Minoru Omura, Youhei Shimasaki, Yuji Oshima, Kei Nakayama, Kazuhiko Kubo, Shuji Aou, Rika Ogata, Miyuki Hirata, Naohide Inoue, Distribution of tributyltin, dibutyltin and monobutyltin in the liver, brain and fat of rats
two-generation toxicity study of tributyltin chloride., Environmental sciences : an international journal of environmental physiology and toxicology, 11, 2, 123-132, 2004, The distribution of tributyltin (TBT) and its metabolites, dibutyltin (DBT) and monobutyltin (MBT), was examined in the liver, brain and fat tissues in a two-generation reproductive toxicity study of tributyltin chloride (TBTCl) in rats using dietary supplementation at concentrations of 5, 25 and 125 ppm. In the liver, irrespective of TBTCl dietary concentration, gender or generation, the highest concentration of metabolite was consistently MBT, followed by DBT, and then TBT. In contrast, TBT was consistently present at the highest concentration in the brain, nearly always followed by DBT and MBT. In fat tissues, the concentrations of the three butyltin compounds showed similar relationships to those observed in the brain, although the concentrations were much lower. In the liver, the concentration of TBT was higher in females, and those of DBT and MBT were higher in males. Factorial ANOVA also suggested the effect of gender on the concentrations of the three butyltin compounds in the liver. The results of this study suggest tissue-dependent distribution of TBT, DBT and MBT and gender-dependent distribution of the three metabolites in the liver of rats..
211. Kang IJ, Yokota H, Oshima Y, Tsuruda Y, Hano T, Maeda M, Imada N, Tadokoro H and Honjo T, Effects of 4-nonylphenol on reproduction of japanese medaka (Oryzias latipes), Environ Toxicol Chem, 10.1897/02-225, 22, 10, 2438-2445, 22:2438-2445, 2003.01.
212. Yohei Shimasaki, Takeshi Kitano, Yuji Oshima, Suguru Inoue, Nobuyoshi Imada, Tsuneo Honjo, Tributyltin causes masculinization in fish, Environmental Toxicology and Chemistry, 10.1002/etc.5620220118, 22, 1, 141-144, 2003.01, We examined the effect of tributyltin (TBT) on the sex differentiation process in genetically female Japanese flounder (Paralichthys olivaceus). The fish were fed an artificial diet containing tributyltin oxide (TBTO) at concentrations of 0.1 and 1.0 μg/g diet from 35 to 100 d after hatching, which includes the sex differentiation period. The ratio of sex-reversed males significantly increased to 25.7% of the flounder fed the 0.1 μg/g diet and to 31.1% of those fed the 1.0 μg/g diet compared with the control (2.2%). From morphological and histological examination of the fish in the TBT-treated groups, normal females had typical ovaries and sex-reversed males had typical testes. These results clearly demonstrated the masculinization of flounder exposed to TBTO. This is the first report of TBT inducing sex reversal in vertebrates..
213. Ik Joon Kang, Hirofumi Yokota, Yuji Oshima, Yukinari Tsuruda, Toshiaki Oe, Nobuyoshi Imada, Hiroshi Tadokoro, Tsuneo Honjo, Effects of bisphenol A on the reproduction of Japanese medaka (Oryzias latipes), Environmental Toxicology and Chemistry, 21, 11, 2394-2400, 2002.11, We elucidated the effects of bisphenol A (BPA) on the reproductive capacity (fecundity and fertility) and estrogenic response of adult Japanese medaka (Oryzias latipes) and studied the transgenerational effects (F1 generation growth and sex) of this agent on the F1 offspring. Eight mating pairs of medaka were exposed to BPA for three weeks at a measured concentration of 837, 1, 720, or 3, 120 μg/L. Throughout the exposure period, we observed no reduction of fecundity and fertility in any treatment group and no reduction in survival and growth or any imbalance of the sex ratio of the offspring. However, histologic examination revealed testis-ova in 13% of the males in the 837-μg/L treatment group, 86% of those in the 1, 720-μg/L group, and 50% of those that received 3, 120 μg BPA/L. In addition, concentrations of hepatic vitellogenin were increased significantly in males treated with BPA at 3, 120 μg/L (p = 0.0148). These results suggest that BPA is a weakly estrogenic compound that has the potential to alter sexual development and induce vitellogenin in male medaka but that has no adverse effect on reproductive success..
214. Miyake K, Tachida H, Oshima Y, Arai R, Kimura S, Imada N and Honjo T, Genetic variation of the cytochorome b gene in the rosy bitterling, Rhodeus ocellatus (Cyprinidae) in Japan., Ichthyol Res, 10.1007/s10228-001-8124-7, 48, 2, 105-110, 48: 105-110, 2002.01.
215. Shimasaki Y, Oshima Y, Yokota Y, Kitano T, Nakao M, Kawabata S, Imada N and Honjo T., Purification and identification of a TBT-binding protein from serum of Japanese flounder, Paralichthys olivaceus., Environ Toxicol Chem, 22: 141-144., 2002.01.
216. Kang IJ, Yokota H, Oshima Y, Tsuruda Y, Yamaguchi T, Maeda M, Imada N, Tadokoro H and Honjo T, Effect of 17_-estradiol on the reproduction of Japanese medaka (Oryzias latipes), Chemosphere, 10.1016/S0045-6535(01)00205-3, 47, 1, 71-80, 47:71-80, 2002.01.
217. Yokota H, Morita H, Nakano N, Kang IJ, Tadokoro H, Oshima Y, Honjo T and Kobayashi K, Development of an ELISA for determination of the hepatic vitellogenin in medaka (Oryzias latipes), Jpn J Environ Toxicol, 4:87-98, 2002.01.
218. Omura M, Ogata R, Kubo K, Shimasaki Y, Aou S, Oshima Y, Tanaka A, Hirata M, Makita Y and Inoue N, Two-generation reproductive toxicity study of tributyltin chloride in male rats., Toxicol Sci, 10.1093/toxsci/64.2.224, 64, 2, 224-232, 64: 224-232., 2002.01.
219. Kang IJ, Yokota H, Oshima Y, Tsuruda Y, Yamaguchi T, Oe T, Imada N, Tadokoro H and Honjo T., Effects of bisphenol A on the reproduction of Japanese medaka (Oryzias latipes)., Environ Toxicol Chem, 10.1897/1551-5028(2002)021<2394:EOBAOT>2.0.CO;2, 21, 11, 2394-2400, 20:2394-2400, 2002.01.
220. Shimasaki Y, KitanoT, Oshima Y, Inoue S, Imada N and Honjo T., Tributyltin causes masculinization in fish, Environ Toxicol Chem, 10.1897/1551-5028(2003)022<0141:TCMIF>2.0.CO;2, 22, 1, 141-144, 22: 141-144, 2002.01.
221. Oshima Y, Kang IJ, Kobayashi M, Nakayama K, Imada N, Tadokoro H and Honjo T., Suppression of sexual behavior in male Japanese medaka (Oryzias latipes) exposed to 17_-estradiol, Chemospheres, 10.1016/S0045-6535(02)00494-0, 50, 3, 429-436, 50: 429-436, 2002.01.
222. 井上 英,大嶋雄治,今田信良,本城凡夫, 北部九州とその周辺水域におけるトリブチルスズ汚染, 環境毒性学会誌, 5: 43-50, 2002.01.
223. Shimasaki Y, Oshima Y, Yokota Y, Kitano T, Nakao M, Kawabata S, Imada N and Honjo T., Purification and identification of a TBT-binding protein from serum of Japanese flounder, Paralichthys olivaceus., Environ Toxicol Chem, 10.1897/1551-5028(2002)021<1229:PAIOAT>2.0.CO;2, 21, 6, 1229-1235, 21: 1229-1235., 2002.01.
224. Yohei Shimasaki, Yuji Oshima, Yoshiko Yokota, Takeshi Kitano, Miki Nakao, Shun Ichiro Kawabata, Nobuyoshi Imada, Tsuneo Honjo, Purification and identification of a tributyltin-binding protein from serum of Japanese flounder, Paralichthys olivaceus, Environmental Toxicology and Chemistry, 21, 6, 1229-1235, 2002.01, Tributyltin (TBT) is an industrial chemical used as an antifoulant in marine environments. Previously, we reported that TBT accumulates in the serum or plasma of some fishes and is bound to a high molecular weight compound in the serum of the Japanese flounder Paralichthys olivaceus. In this study, we succeeded in purifying the TBT-binding protein (TBT-bp) from the serum of Japanese flounder by using gel filtration chromatography, anion exchange chromatography, and polyacrylamide gel electrophoresis, with a 2.6% yield and a 77-fold purification. The molecular mass of TBT-bp was approximately 46.5 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its isoelectric point was approximately 3.0 on isoelectric focusing-polyacrylamide gel electrophoresis. The TBT-bp contained 42% N-glycan. The cDNA nucleotide sequence of TBT-bp was determined by reverse transcription-polymerase chain reaction of Japanese flounder liver, and we deduced a sequence of 191 amino acids of mature TBT-bp. No sequence identical to the TBT-bp amino acid sequence was found within the SWISS-PROT (http://www.nig. ac.jp/) protein database; however, a lipocalin-like sequence pattern was observed. We concluded that the TBT-bp was a novel protein that has not yet been reported, although some DNA sequences from expressed sequence tags (ESTs) of Japanese flounder liver had a high identity. A high expression level of TBT-bp gene was found in the liver, but the gene was slightly detectable in the kidney and brain..
225. Omura M, Ogata R, Kubo K, Shimasaki Y, Aou S, Oshima Y, Tanaka A, Hirata M, Makita Y and Inoue N., Two-generation reproductive toxicity study of tributyltin chloride in male rats., Toxicol Sci, 10.1093/toxsci/64.2.224, 64, 2, 224-232, 64: 224-232., 2001.01.
226. Ogata R, Omura M, Shimasaki Y, Kubo K, Oshima Y, Aou S and Inoue N., Two-generation reproductive toxicity study of tributytin chloride in female rats., J Toxicol Environ Health A, 10.1080/15287390151126469, 63, 2, 127-144, 63: 127 ?144., 2001.01.
227. Yokota H, Seki M, Maeda M, Oshima Y, Tadokoro H, Honjo T and Kobayashi K., Life cycle toxicity of 4-nitrophenol to medaka (Orzias latipes)., Environ Toxicol Chem, 10.1897/1551-5028(2001)020<2552:LCTONT>2.0.CO;2, 20, 11, 2552-2560, 20: 2552-2560., 2001.01.
228. Imada N, Honjo T, Kim DI and Oshima Y, Transfer of Heterocapsa circularisquama with shellfish consignments and the possibility of its establishment in new area., ITE Letters, 2: 264-267., 2001.01.
229. Kunio Kobayashi, Hiroshi Tadokoro, Masanobu Maeda, Masanori Seki, Hirofumi Yokota, Tsuneo Honjo, Yuji Oshima, Life-cycle toxicity of 4-nonylphenol to medaka (Oryzias latipes), Environmental Toxicology and Chemistry, 20, 11, 2552-2560, 2001.01, We studied the chronic effects of 4-nonylphenol (4-NP) on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure. The exposure study of the parental (F0) medaka was begun on embryos within 24 h postfertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction under flow-through exposures to mean measured 4-NP concentrations of 4.2, 8.2, 17.7, 51,5, and 183 μg/L for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. The 183-μg/L treatment significantly reduced the embryo survival and swim-up success of the F0 fish. The cumulative mortality after swim-up of the F0 fish exposed to 17.7 and 51.5 μg/L were significantly higher than the control mortality. No concentration-related effect of 4-NP was observed on the growth of surviving F0 fish at 60 d posthatch. However, the sex ratio estimated from the appearance of their secondary sex characteristics was skewed toward female in the 51.5-μg/L treatment. Additionally, gonadal histology showed that 20% of the fish in the 17.7-μg/L treatment and 40% in the 51.5-μg/L treatment had testis-ova, indicating that 4-NP affects the gonadal development and survival of medaka at similar concentrations in juveniles. The sex ratio of the F0 fish in the 51.5-μg/L treatment was completely skewed toward female; subsequently, the effects on fecundity and fertility in this generation were monitored at mean measured concentrations of 4.2, 8.2, and 17.7 μg/L from 71 to 103 d posthatch. Fecundity was unaffected by any of the treatments examined. The mean fertility in the 17.7-μg/L treatment was reduced to 76% of that in the controls, although no statistically significant differences were determined. Overall, these results indicate that the lowest-observed-effect concentration (LOEC) and no-observed-effect concentration (NOEC) of 4-NP through the life cycle of the F0 medaka were 17.7 and 8.2 μg/L, respectively. In the F1 medaka, no significant effects were observed on hatching success, posthatch mortality, or growth, but sexual differentiation at 60 d posthatch was affected. Induction of testis-ova in the gonads of the F1 fish was observed in both the 8,2- and the 17.7-μg/L concentrations. The results indicate that 4-NP can have significant effects on reproductive potential of medaka at concentrations as low as 17.7 μg/L..
230. Hirofumi Yokota, Yukinari Tsuruda, Masanobu Maeda, Yuji Oshima, Hiroshi Tadokoro, Akinobu Nakazono, Tsuneo Honjo, Kunio Kobayashi, Effect of bisphenol a on the early life stage in Japanese medaka (Oryzias latipes), Environmental Toxicology and Chemistry, 19, 7, 1925-1930, 2000.07, Japanese medaka (Oryzias latipes) were exposed to bisphenol A (BPA) at the sublethal concentrations of 2.28, 13.0, 71.2, 355, and 1,820 μg/L (as mean measured concentrations) in the early life stage from fertilized eggs to 60-d posthatch. Except for the growth and sexual differentiation of the fish at 60-d posthatch, no effects were observed on hatching success and time to hatching in embryological stage and on mortality and abnormal behavior and appearance in hatched larvae. The growth of the fish was suppressed with increasing BPA concentrations, resulting in significant differences in both the total length and body weight of medaka at 1,820 μg/L compared with the controls. When observed for their external secondary sex characteristics, no males were identified in the 1,820-μg/L treatment. In addition, histological examination showed that 32% of fish in the 1,820-μg/L group had testis-ova composed of both testicular germ cells and oocytes. Consequently, the lowest effective concentration for the early life stage of medaka was between 355 and 1,820 μg/L. Since the environmental concentrations of BPA are usually three orders lower than the lowest effective concentration, BPA alone may not affect the early life stage of wild fish populations..
231. Lee R, Kim GB, Maruya KA, Steinert SA and Oshima Y, DNA strand breaks (comet assay) and embryo development effects in grass shrimp (Palaemonetes pugio) embryos after exposure to genotoxicants., Mar Environ Res, 10.1016/S0141-1136(00)00110-0, 50, 1-5, 553-557, 50: 553-557., 2000.01.
232. Yokota H, Tsuruda Y, Maeda M, Oshima Y, Tadokoro H, Nakazono A, Honjo T and Kobayashi K., Effect of bisphenol A on the early life stage in Japanese medaka (Oryzias latipes)., Environ Toxicol Chem, 10.1897/1551-5028(2000)019<1925:EOBAOT>2.3.CO;2, 19, 7, 1925-1930, 19: 1925-1930., 2000.01.
233. Richard F. Lee, Scott A. Steinert, K. Nakayama, Yugi Oshima, Use of DNA strand damage (Comet assay) and embryo hatching effects to assess contaminant exposure in blue crab (Callinectes sapidus) embryos, Proceedings of the 1998 8th Symposium on Environmental Toxicology and Risk Assessment: Standardization of Biomarkers for Endocrine Disruption and Environmental Assessment ASTM Special Technical Publication, 1364, 341-349, 1999.12, After fertilization, blue crab eggs are embedded in a `sponge' which is attached to the female abdomen during embryo development. Embryos after 9 stages in the egg sac hatch into a swimming zoea stage (stage 10). We have developed a bioassay where embryo development is monitored in culture plates with and without toxicants in the water. Toxicant effects are based on determining the percentage of embryos which hatch to zoea. Hatching EC50 (toxicant concentration at which 50% of the embryos fail to hatch) for a number of pesticides, organometallics and metals were determined. The test takes from 2 to 6 days depending on the embryo stage selected for the study. In addition to embryo development effects the prevalence of DNA single-strand breaks in individual embryo cells were determined using the single cell gel electrophoresis method (Comet assay). A good correlation between DNA strand breakage and embryo defects was found after exposure to genotoxic contaminants. Thus, the bioassay linking DNA damage to embryo hatching effects is rapid, sensitive and mechanistically relevant..
234. Nirmala K, Oshima Y, Lee R, Imada N, Honjo T and Kobayashi K, Transgenerational toxicity of tributyltin and its combined effects with polychlorinated biphenyls on reproductive processes in Japanese medaka (Oryzias latipes)., Environ Toxicol Chem, 10.1897/1551-5028(1999)018<0717:TTOTAI>2.3.CO;2, 18, 4, 717-721, 18: 717-721., 1999.01.
235. Kukuh Nirmala, Yuji Oshima, Richard Lee, Nobuyoshi Imada, Tsuneo Honjo, Kunio Kobayashi, Transgenerational toxicity of tributyltin and its combined effects with polychlorinated biphenyls on reproductive processes in Japanese medaka (Oryzias latipes), Environmental Toxicology and Chemistry, 18, 4, 717-721, 1999.03, Japanese medaka (Oryzias latipes) were fed daily on one of four diets containing tributyltin (TBT), PCBs, a combination of TBT and PCBs, or a control diet (with nothing added). Contaminant doses were 1 μg/g body weight per day for 3 weeks. The combination of TBT and PCB showed additive effects on the spawning of medaka, resulting in a significant reduction in spawning frequency, and on the number of spawned eggs and fertilization success when compared with effects in fish fed either a TBT or PCB diet. The adverse effects on the reproductive success of medaka may have been due to endocrine disruption caused by accumulation of both TBT and PCB. The TBT treatment significantly reduced embryo and larval survival from eggs (279 ng TBT/g), which were spawned from females containing 2,390 ng TBT/g body weight from the TBT diet. This result indicates transgenerational toxicity. The PCB diet caused fewer adverse effects than the TBT diet with respect to spawning frequency, egg survival, hatching, and swim-up success of larvae. When both TBT and PCB were in the diet, there were additive effects on spawning success as noted above but antagonistic effects on embryological success of eggs and swim-up success of larvae..
236. Yuji Oshima, Tatsusuke Takeda, Effect of Temperature on Concentrations of Drug in Fish Serum, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.65.910, 65, 5, 910-911, 1999.01.
237. Yuji Oshima, Comibined effects of pollution on the reproductive processes of fish, Nippon Suisan Gakkaishi (Japanese Edition), 64, 5, 905-906, 1998.12.
238. Lee R and Oshima Y, Effects of selected pesticides, metals and organometallics on development of blue crab (Callinectes sapidus) embryos., Mar Environ Res, 10.1016/S0141-1136(97)00072-X, 46, 1-5, 479-482, 46: 479-482, 1998.01.
239. Yuji Oshima, Shinsuke Tanabe, Shinya Hashimoto, Toshihiro Horiguchi, Effects of Endocrine Disrupting Chemicals on Aquatic Organisms, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.64.898, 64, 5, 1998.01.
240. Oshima Y, Nirmala K, Yokota Y, Go J, Shimasaki Y, Nakao M, Lee RF, Imada N, Honjo T and Kobayashi K, Accumulation of tributyltin (TBT) in the blood of flounder and dab intraperitoneally administered with TBT, Mar Environ Res, 10.1016/S0141-1136(97)00082-2, 46, 1-5, 587-590, 46: 587-590, 1997.01.
241. Oshima Y, Nirmala K, Go J, Yokota Y, Koyama J, Imada N, Honjo T and Kobayashi K., High accumulation of tributyltin in blood among the tissues of fish and applicability to environmental monitoring., Environ Toxicol Chem, 10.1897/1551-5028(1997)016<1515:SCHAOT>2.3.CO;2, 16, 7, 1515-1517, 16: 1515-1517, 1997.01.
242. Yuji Oshima, Liestiaty Fachrudin, Noriko Ishida, Nobuyoshi Imada, Kunio Kobayashi, Effect of Drug-metabolizing Enzyme Activity Induced by PCB on the Residence Time of Oxolinic Acid, Piromidic Acid and Nalidixic Acid in Carp, Fisheries science, 10.2331/fishsci.62.302, 62, 2, 302-306, 1996.01, A study was made of the effect of drug-metabolizing enzyme activity induced by polychlorinated biphenyl (PCB) on the residence time of quinoline antibacterial agents in carp Cyprinus carpio. Carp were fed with a diet containing PCB (1 mg PCB/kg body weight/day) for 2 weeks to induce drug-metabolizing enzymes. After pretreatment, three kinds of quinoline antibacterial agents (oxolinic acid, piromidic acid and nalidixic acid) were individually administered in feed to PCB-treated or nontreated (as control) fish as a single dose of 20 mg/kg body weight. The peak concentrations of oxolinic acid in the blood, liver and muscle of PCB-treated fish were lower than half of those in the control. The concentrations of piromidic acid in the liver, muscle and kidney of PCB-treated fish were undetectable throughout the experiment (2 to 98 h post dosing), except in the blood. However, the residence time and concentration of nalidixic acid in the tissues of PCB-treated fish showed no significant difference compared with those in the control..
243. Y. Oshima, K. Kobayashi, L. Fachrudin, N. Ishida, Effect of the induced drug-metabolizing enzyme activity on the duration of oxolinic acid in fish, Marine Environmental Research, 10.1016/0141-1136(95)00071-2, 42, 1-4, 335-338, 1996.01, One group of 60 carp (ca 100 g each) were fed with a diet containing polychlorinated biphenyl (PCB) (1 mg PCB/kg body weight/day) for 2 weeks to induce drug-metabolizing enzymes. A second group of 60 carp were fed a PCB-free diet as a control. After pretreatment, oxolinic acid (OA) was administered in feed to PCB-treated and control fish in a single dose of 20 mg OA/kg body weight. The peak concentrations of OA in the blood, liver and muscle of PCB-treated fish were lower than half of those in the control. Furthermore, the duration times of OA in the liver and blood of PCB-treated fish were also shortened compared with those in the control. In another test in vitro with hepatic microsomes, the produced amount of dihydroxy-OA in PCB-treated fish increased more than 30-fold compared with that in controls. These facts suggest that the induction of the drug-metabolizing enzyme activity by pollutants such as PCB, will result in large differences in the duration of drugs in fish, when the drugs accept enzymatic reactions..
244. Richard F. Lee, Kristen O'Malley, Yugi Oshima, Effects of toxicants on developing oocytes and embryos of the blue crab, Callinectes sapidus, Marine Environmental Research, 10.1016/0141-1136(95)00079-8, 42, 1-4, 125-128, 1996.01, Oocytes (90 μm in diameter) were isolated from ovaries of 14-day post-molt adult female crabs and maintained in culture media. The addition of cadmium (20 μg/ liter) or tributyltin (2 μg/liter) to developing oocytes resulted in decreases in the growth of oocytes as measured by protein and lipovitellin accumulation relative to controls. Crab embryos isolated from yellow 'sponge' of female blue crabs were maintained in seawater until hatching (6-8 days). Toxicants tested included cadmium, copper, tributyltin and endosulfan. Some of the processes or events which were followed included water uptake, lipovitellin utilization rate, formation of appendages, formation of a heart, formation of eyespots and hatching to zoea stage. The primary effects from addition of toxicants were deformed eyespots and reduced hatching success. The hatching EC50 (concentration at which 50% of embryos failed to hatch) for copper, cadmium, tributyltin and endosulfan were 3.1, 0.25, 0.047 and 450 μg/liter, respectively. Crab embryos appear to be suitable for testing of the effects of a variety of toxicants with advantages including low cost, reproducibility, low variability and sensitivity..
245. Yuji Oshima, K. Kobayashi, C. Hidaka, S. Izu, N. Imada, Differences in the drug-metabolizing enzyme activities among fish and bivalves living in waters near industrial and non-industrial areas, Bulletin of Environmental Contamination and Toxicology, 10.1007/BF00205146, 53, 1, 106-112, 1994.07.
246. Y. Oshima, K. Kobayashi, J. F. Lumbanbatu, K. Ooie, Y. Kawahara, N. Imada, Effect of drug-metabolizing enzyme activity induced by PCB on the duration of drugs in fish, Aquaculture, 10.1016/0044-8486(94)90218-6, 120, 1-2, 25-31, 1994.02, A study was made of the induction of drug-metabolizing enzyme activity and the effect of the induced activity on the duration of drugs in fish. Carp were fed with a diet containing PCB ( 0.1 mg PCB 100 g body weight day-1) for 2 weeks to induce drug-metabolizing enzymes. After pretreatment, oxolinic acid, thiamphenicol and oxytetracycline were administered in feed to PCB-treated and nontreated (as control) fish as a single dose of 20, 50, and 50 mg/kg body weight, respectively. The peak concentrations of oxolinic acid in the blood, kidney, liver, and muscle of fish in the PCB group were lower than the half of those in the controls. Furthermore, the duration times of oxolinic acid in the tissues of PCB-treated fish were also shorter than those in the control. However, the duration of thiamphenicol and oxytetracycline showed no significant changes relating to PCB treatment..
247. Yang Wang, Rizald Max Rompas, Kunio Kobayashi, Yuji Oshima, Nobuyoshi Imada, Mechanism of the Reduction of Fenitrothion Toxicity in Kuruma Prawn by Piperonyl Butoxide, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.59.1581, 59, 9, 1581-1585, 1993.01, A study on the relation between the toxicity of fenitrothion (FS) and its metabolism in kuruma prawn Penaeus japonicus treated with piperonyl butoxide (PB) was performed to elucidate the cause of the remarkable reduction of FS toxicity in the prawn by PB treatment, using 14C labeled FS. The PB treatment did not affect FS absorption by the prawn from media, but it considerably inhibited the biotransformation of FS to fenitrooxon (FO), i.e. the reduction of FS toxicity in the prawn by PB treatment was attributed to the decrease in FO formation. The minimum lethal concentration of FO in the prawn was presumed to be 10–14 pmol/g, whereas that of FS was higher than 400 pmol/g. According to the amounts of FS and its metabolites found in kuruma prawn treated with and without PB, the main metabolic pathway of FS in the prawn was presumed to be FS→FO→desmethylfenitrooxon→3-methyl-4-nitrophenol→its conjugates..
248. Kunio Kobayashi, Yang Wang, Shigeo Kimura, Rizald Max Rompas, Nobuyoshi Imada, Yuji Oshima, Practical Application of Piperonyl Butoxide for the Reduction of Organophosphorus Insecticide-Toxicity to Kuruma Prawn., Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.59.2053, 59, 12, 2053-2057, 1993.01, A study was carried out to set up a practical application of piperonyl butoxide (PB) for the reduction of organophosphorus insecticide-toxicity to kuruma prawn Penaeus japonicus. The absorption and excretion of PB administered through the diet to kuruma prawn was ex amined, compared with the case of exposure to PB-seawater. The concentration of PB in the prawn reached a maximum of 13µg/g at 3-h after feeding with a 1% PB-diet for 6h, which was a similar level to the PB in kuruma prawn exposed to 1ppm PB-seawater for 12h. By feeding with a 1% PB-diet, the survival times of kuruma prawn exposed to fenitrothion (0.01ppm), malathion (0.2ppm), dioxabenzofos (0.4ppm), phenthoate (0.1ppm), and diazinon (0.1ppm) were extended by ca. 11, 5, 5, 3, and 2.5 times over those of the respective control prawns fed with a PB-free diet. However, PB was not effective in reducing the toxicity of dichlorvos (1ppm) (a typical oxo-form insecticide) to kuruma prawn..
249. Kunio Kobayashi, Yang Wang, Nobuyoshi Imada, Yuji Oshima, Rizald Max Rompas, Reduction of the Toxicity of Fenitrothion to Prawns by Piperonyl Butoxide, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.59.717, 59, 4, 717-720, 1993.01, The effectiveness of piperonyl butoxide (PB) in reducing the mortality of striped prawn and kuruma prawn during exposure to fenitrothion (FS) was examined. The 24-h LC50 values of PB for striped and kuruma prawns were 3.5 and 1.6 ppm at 25°C, respectively. Therefore, PB-treatment for both prawns was conducted at 0.25 ppm, corresponding to one-tenth of the mean of both 24-h LC50 values. The PB-pretreatment before FS-exposure and also the addition of PB to FS-water were effective in decreasing the FS-toxicity to both prawns. The most effective reduction of the toxicity to the prawns was obtained by continuous PB-treatment before and during FS-exposure, resulting in extensions of 50% survival time by 4–6 times in striped prawn and 10–16 times in kuruma prawn, compared with the respective control groups non-treated with PB..
250. K. Kobayashi, R. M. Rompas, N. Imada, Yuji Oshima, Mechanism of abrupt increase in toxicity of organophosphorothionates to tiger shrimp larvae with progress of stages, Proceedings of the 15th Biennial Conference of the International Association on Water Pollution Research and Control Water Science and Technology, 23, 487-496, 1991.01, To elucidate the cause of an abrupt increase in the toxicity of organophosphorus pesticides to tiger shrimp Penaeus japonicus with the progress of larval stages, the toxicity of the pesticides to the shrimp larvae and the inhibition of larval acetylcholinesterase (AChE) by the pesticides, and the metabolism of fenitrothion (FS) in the larvae were studied at different stages, respectively. The toxicity of thiono-forms to the larvae increased abruptly with the progress of stages, whereas that of oxo-forms was unchanged from nauplius to postlarva. The susceptibility of larval AChE to each pesticide was almost unchanged in these stages. FS metabolic activity of zoea was very low, but the activity increased abruptly with their growth and resulted in the increase of fenitrooxon which displays extremely high toxicity as compared with FS, i.e., the increase in the toxicity of thiono-forms to shrimp larvae with the progress of the stages must be due to the increase in the oxidative desulfuration activity..
251. Nobuyoshi Imada, Kunio Kobayashi, Koichi Tahara, Yuji Oshima, Production of an Autoinhibitor by Skeletonema costatum and Its Effect on the Growth of Other Phytoplankton, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.57.2285, 57, 12, 2285-2290, 1991.01, In order to elucidate the production of an autoinhibitor by Skektonema costatum and its producing phase, four phases in the growth process were selected. The autoinhibitor was extracted from S. costatum and its cultured medium at each phase with ethyl acetate and subjected to the growth inhibition test for S. costatum. The autoinhibitor was produced gradually from the exponential growth phase of S. costatum and mostly accumulated in the cells up to the stationary phase. However, the inhibitor in the dying or dead cells was rapidly released into the medium, resulting in the increase in the concentration of the inhibitor in the medium. After almost all the cells died, the large portion of the inhibitor produced by S. costatum was found in the medium. This autoinhibitor also prevented the growth of other diatoms and Chattonella, but it did not show any inhibitory effect on the growth of dinoflagellates..
252. Kunio Kobayashi, Yuji Oshima, Nobuyoshi Imada, Rizald Max Rompas, A Comparative Study on the Toxicity, Absorption and Depuration of Fenitrothion and Its Oxon in Japanese Tiger Shrimp, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.56.923, 56, 6, 923-928, 1990.01, A comparative study has been made of the toxicity, absorption and depuration of fenitrothion (dimethyl 3-methy1-4-nitrophenyl phosphorothionate; FS) and its oxon (FO) in Japanese tiger shrimp Penaeus japonicus. It has been previously reported that the toxicity of FO to the shrimp was approx. 10–20 times higher than that of FS in the intramuscular administration test, and also that FO showed ca. 12, 000 times high acetylcholinesterase inhibition compared with FS. In the lethal concentration (LC50) test, however, the toxicity of FO to young and juvenile tiger shrimp was only 1/10-1/50 that of FS, contrary to its toxicity in vivo. The results in the absorption and depuration test of [14C} FS and [14C] FO for tiger shrimp juvenile, demonstrated that the absorption rate of FS in the shrimp was approx. 40 times that of FO, and that the FS absorbed by the shrimp from surrounding water was rapidly biotransformed to more toxic FO, resulting in the high toxicity of FS to the shrimp compared with FO in the LC50 test..
253. Kunio Kobayashi, Rizald Max Rompas, Takako Maekawa, Nobuyoshi Imada, Yuji Oshima, Changes in Metabolic Activity of Tiger Shrimp Larvae at Different Stages to Fenitrothion, An Organophosphorus Insecticide, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.56.489, 56, 3, 489-496, 1990.01, A study was performed on the metabolism of fenitrothion (FS) in tiger shrimp Penaeus japonicus at different larval stages to elucidate the cause of the remarkable increase in the toxicity of organophosphorothionates to the shrimp larvae with the progress of the stages. The shrimp larvae (zoea, mysis and postlarvae) were exposed to 0.5 ppb [14C]FS. After 1.5-12 h exposure, [14C]FS and its metabolites accumulated in the larvae were extracted with benzene and then with ethyl ether. The benzene-extracts were determined by TLC and the ethyl ether-extracts were subjected to an enzymatic analysis. Zoea and mysis showed very low FS metabolic activity, and most of the FS absorbed by the larvae was present as FS itself in their bodies. However, their FS metabolic activity increased abruptly with their growth and resulted in an increase in the amount of fenitrooxon which displays extremely high toxicity as compared with FS, accompanying the simultaneous increase in the FS detoxication activity such as demethylation, hydrolysis and conjugation. The occurrence of the remarkable increase in the toxicity of organophosphorothionates to tiger shrimp larvae with the progress of the stages is probably due to the increase in the oxidative desulfuration activity, beyond the effect of the detoxication activity..
254. Rizald Max Rompas, Kunio Kobayashi, Yuji Oshima, Koyuki Yamato, Nobuyoshi Imada, Yukiko Mitsuyasu, Relationship between Toxicity and Acetylcholinesterase Inhibition of Some Thiono- and Oxo-form Organophosphates in Tiger Shrimp Larvae at Different Stages, Nippon Suisan Gakkaishi (Japanese Edition), 10.2331/suisan.55.669, 55, 4, 669-673, 1989.01, A study was made regarding the relationship between the toxicity and acetylcholinesterase (AChE) inhibition of three organophosphorothionates (fenitrothion, FS; diazinon, DIN; phenthoate, PAP) and three oxo-forms (fenitrooxon, FO; diazoxon, DOX; dichlorvos, DDVP) in tiger shrimp Penaeus japonicus at different larval stages. The shrimp larvae at nauplius and zoea stages showed relatively high resistance to FS, DIN and PAP, i.e.> the respective 24-h LC60values were 1.84, 10.5 and 5 ppm. However, the toxicity of these thiono-form phosphates increased abruptly with the progress of the larval stages, especially after metamorphosis into the postlarva, resulting in the increase by ca. 2,600, 1,200 and 850 times respectively to that of nauplius stage. On the other hand, the toxicity of FO and DDVP to the larvae was almost unchanged throughout these stages, at the levels of ca. 7 ppb and 5.6 ppm as the 24-h LCe0value, respectively. The susceptibility of the larval AChE to the tested phosphates was almost unchanged from zoea to postIarva. The concentrations of FO, DDVP, DOX, FS, PAP and DIN producing 50% inhibition (I50) of the AChE activity were approx. 0.015, 0.35, 1.27, 200, 650 and 1,200 μm, respectively. Although FS showed the highest AChE inhibition among the thiono-forms; its oxon (FO) displayed 12,000 times high AChE inhibition compared to FS. The high AChE inhibition of FO was in good correlation with its high toxicity to the larvae even at the early stage..
255. Kunio Kobayashi, Yuji Oshima, Yang Wang, Chie Taguchi, Induction of Drug-Metabolizing Enzymes by Long-Term Administration of PCB and Duration of Their Induced Activities in Carp, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.53.487, 53, 3, 487-491, 1987.01, A study was made of the induction of drug-metabolizing enzymes by a long-term administration of PCB-diet and also the duration of their induced activities in the hepatopancreas of carp Cyprinus carpio. In a preliminary experiment comparing the inductivity of hepatic drug-oxidase, PCB among the tested environmental contaminants was most effective as the inducer of cytochrome P-450. Therefore, a subsequent experiment was performed to elucidate the effect of long-term administration of PCB (0.05 mg/100 g-body weight/day) for 16 weeks on drug-metabolizing enzymes in the hepatopancreas of carp. The dietary administration of PCB induced not only the cyt. P-450 content and the activities of aryl hydrocarbon hydroxylase and O-dealkylase, but also the glutathione content and the activities of glutathione- and UDPglucuronosyl-transferase. However, the increase of these contents and activities during PCB administration occurred mostly within 2- or 4-week period, resulting in almost no further increase in spite of the continuous PCB administration for 16 weeks. The induced contents and activities were kept for a fairly long time even after discontinuance of PCB administration..
256. Kunio Kobayashi, Yuji Oshima, Shigehito Hamada, Chie Taguchi, Induction of Phenol-Sulfate Conjugating Activity by Exposure to Phenols and Duration of Its Induced Activity in Short-necked Clam, Nippon Suisan Gakkaishi, 10.2331/suisan.53.2073, 53, 11, 2073-2076, 1987.01, A study was made of the induction of phenol-sulfate conjugating activity by exposure to some phenolic compounds and also the duration of its activity induced by pentachlorophenol (PCP) in the mid-gut gland of short-necked clam Ruditapes philippinarum. In a preliminary experiment comparing the inductivity of phenol-sulfate conjugating activity in short-necked clam among PCP, resorcinol, p-cresol, p-chlorophenol, p-nitrophenol and phenol; PCP was the most effective inducer, resulting in a 2.4-fold activity in the control clam during the 3-day exposure period to 0.1 ppm PCP. Therefore, a subsequent experiment was performed to elucidate the effect of long-term exposure to sublethal PCP (0.1 ppm) for 5 weeks on the phenolsulfate conjugating activity in clams, feeding on a unicellular green alga Dunaliella sp. by dipping the clams in its growing sea water-medium (ca. 4 x 104 cells/m/) for 2–3 h every other day, when the test PCP-water was replaced by a newly prepared one. The conjugating activity in the clam increased with the time of exposure to PCP and reached 42 nmol/min/g-tissue at 5-week period, corresponding to ca. 7-fold with that in the control. When the clams which were exposed to 0.1 ppm PCP for 2 weeks and then transferred to PCP-free sea water, its induced activity of 24 nmol/ min/g-tissue decreased gradually, but it was still at a level of 1.5-fold with that in the control even after 3 weeks, although the biological half-life of PCP accumulated in the clam was only ca. 1 h..
257. N. Imada, K. Kobayashi, Y. Oshima, T. Nakao, Utilization of nitrogen and phosphorus from treated sewage and bay-sediment by marine algae, Unknown Journal, 42, 1-2, 37-44, 1987.01, The main sources of nitrogen and phosphorus in Hakata Bay are the effluent from the sewage disposal plants and the bay sediments. The present paper deals with the utilization of nitrogen and phosphorus which are contained in the effluent from Fukuoka Eastern Sewage Disposal Plant and released from the sediment in Hakata Bay by an important laver in fishery, Porphyra yezoensis and its competitors such as green lavers Enteromorpha sp. and Ulva pertusa and also a diatom Skeletonema costatum. 1. All lavers used in the experiment utilized NH4-N from the effluent and bay sediment rather than NO3-N in the standard medium. The weight increment of Enteromorpha sp. was the highest among the tested lavers corresponding to about twice that of P. yezoensis, but no difference was observed in absorption of N and P between both lavers. Those of U. pertusa were the lowest among the lavers used. 2. Although the growth of S. costatum decreases with lowering temperature, its weight gain and the absorbed amounts of N and P were much larger as compared with those of P. yezoensis even at 10°C, corresponding to 15, 6 and 12 times, respectively. 3. The growth of P. yezoensis was not affected by S. costatum coexisting in the same media, when the amounts of nutrients in the media were sufficient. 4. The growth of P. yezoensis and S. costatum was inhibited with the increase of NH4-N level in media more than 8 mg/l and 12 mg/l, respectively. However, S. costatum was more affected by the high level of NH4-N than P. yezoensis, resulting in the rapid decrease of cell number and the death of almost all cells at 32 mg/l after 4 days culture, whereas in the same medium P. yezoensis showed the growth ca. half that in the standard medium (NO3-N) after 3 days. 5. The toxicity of NH4-N to P. yezoensis in the effluent media was lower than that in the artificial media which contain NH4Cl as N-source, resulting in the almost same growth even at 14 mg/l of NH4-N with that in the standard media containing NaNO3 as N-source..
258. Kunio Kobayashi, Shigeo Kimura, Yuji Oshima, Sulfate Conjugation of Various Phenols by Liver-Soluble Fraction of Goldfish, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.50.833, 50, 5, 833-837, 1984.01, A study has been made of the capability of the sulfate conjugating enzyme system in the liver-soluble fraction from goldfish Carassius auratus, to phenol and twenty-one phenolic compounds as follows at various concentrations from 0.00067 to 33.3 mm in reaction media: (1) chlorophenols (o-;p-; 2,4-; 2,4,5-; 2,4,6-; 2,3,4,6-; 2,3,4,5,6-), (2) aminophenols (o-; p-), (3) nitrophenols (m-; o-; p-; 2,4-; 2,4,6-), (4) polyphenols (resorcinol; catechol; pyrogallol), (5) other phenols(p-cresol; o,o’- biphenol; phenolphthalein; phenol red). The liver-soluble fraction showed fairly high activities of the sulfate conjugation for half of the tested phenols corresponding to 53-116 % of that for phenol (246 nmol/h/g-liver), while the negligible conjugation for less than 5% of that for phenol was observed only in three phenols, i.e., 2,4-dinitrophenol, 2,4,6-trinitrophenol and phenol red. On the other hand, some phenols which showed low sulfate conjugation among the tested phenols such as pentachlorophenol strongly inhibited the sulfate conjugating enzyme system..
259. Shigeo Kimura, Yuji Oshima, Kunio Kobayashi, Phenol-Sulfate Conjugating Activity in Liver-Soluble Fraction of Fish, NIPPON SUISAN GAKKAISHI, 10.2331/suisan.48.433, 48, 3, 433-437, 1982.01, The phenol-sulfate conjugation by the liver subcellular fractions from goldfish Carassius auratus, carp Cyprinus carpio, rainbow trout Salmo gairdneri, and Tilapia nilotica has been studied using [35S] K2SO4. The cell fractionation of goldfish liver was examined by the determination of respective markers for nuclear, mitochondrial, lysosomal, microsomal, and soluble fractions. Among those subcellular fractions, only the soluble fraction displayed the conjugating activity. The maximum activity of the enzyme in the soluble fraction was obtained in the presence of 20 µmol of both ATP and Mg2+ in 1.5 ml of medium, although the activity decreased with an excess of ATP and Mg2+. This conjugation was inhibited by more than 0.1 µmol of Ca2+ in 1.5 ml of medium. The enzyme exhibited the conjugating activity in the pH range 7.5–9.5; the optimum value was at 8. In the temperature range 5–40°C, the maximum conjugation in goldfish, Tilapia, and carp occurred at 35°C, in rainbow trout it occurred at 30°C. The phenol-sulfate conjugating activities in goldfish, carp, rainbow trout, Tilapia and albino rat were approximately 340, 82, 66, 200 and 720 nmol/g-liver per h, respectively..
260. Satone H, Akahoshi E, Nakamura A, LEE JAE MAN, Honda M, 川畑 俊一郎, 日下部 宜宏, 大嶋 雄治, Expression and functional characterization of recombinant tributyltin-binding protein type 2. , J Toxicol l Sci, 38, 885-890.