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Akihiko Yamaguchi Last modified date：2024.03.26

Assistant Professor / Marine Bioresources / Department of Bioresource Sciences / Faculty of Agriculture


Papers
1. ＠Akihiko Yamaguchi, Evaluation of fish pituitary spheroids to study annual endocrine reproductive control, General and Comparative Endocrinology 351 (2024) 114481 , https://doi.org/10.1016/j.ygcen.2024.114481, 351　, 2024.03, [URL], The pituitary gland is a small endocrine gland located below the hypothalamus. This gland releases several important hormones and controls the function of many other endocrine system glands to release hormones. Fish pituitary hormonal cells are controlled by neuroendocrine and sex steroid feedback. To study the complex pituitary function in vivo, we established an in vitro pituitary spheroid assay and evaluated its suitability for monitoring the annual reproductive physiological conditions in Takifugu rubripes, also known as torafugu, is one of the most economically important species distributed in the northwestern part of the Pacific Ocean, in the western part of the East China Sea, and in more northern areas near Hokkaido, Japan. Fish pituitary spheroids can be easily constructed in liquid or solid plates. The culture medium (L-15) made the aggregation faster than MEM (Hank’s). A Rho-kinase inhibitor (Y-27632, 10 μM) and/or fish serum (2.5 %) also promoted spheroid formation. Laser confocal microscopy analysis of spheroids cultured with annual serum of both sexes revealed that luteinizing hormone (LH) synthesis has the highest peak in the final maturation stage (3 years old, May) in accordance with the highest serum sex steroid levels; in contrast, follicle stimulating hormone (FSH) synthesis has no correlation with the dose of serum or nutrients. Similarly, 3D cell propagation assays using female serum showed that total pituitary cells displayed the highest proliferation at puberty onset (2 years old, October) before half a year of the spawning season. These results indicate that pituitary spheroids are useful in vitro models for monitoring the reproductive physiological status of fish in vivo and may be applicable to the in vitro screening of environmental chemicals and bioactive compounds affecting reproductive efficiency in aquaculture..
2. Akihiko Yamaguchi, Tomoko Tsunematsu, Yoshihiro Motojima, Kanako Toriyama, Asami Horinouchi, Yukari Ishii, Hanezu Murata, Sota Yoshikawa, Mitsuo Nyuji, Akio Shimizu, Pituitary luteinizing hormone synthesis starts in aromatase (cyp19a1b)‑positive cells expressing esr1 and esr2b at the onset of puberty in Takifugu rubripes (fugu), Cell and Tissue Research, 10.1007/s00441-022-03629-6, 2022.05, Unlike mammals, teleost fsh have high aromatase activity (AA) in the pituitary. However, the cells responsible for oestradiol synthesis and the local physiological roles of this hormone remain unclear. Hence, we investigated the efects of age and development on steroidogenic activity, mRNA expression, and cyp19a1b localization in the pituitary gland of the Japanese puferfsh Takifugu rubripes. Under aquaculture conditions, AA was highest after puberty, and the mRNA expression levels of cyp19a1b and the oestrogen receptors esr1 and 2b and the level of serum testosterone (T) were signifcantly increased after puberty compared with the other developmental stages in male and female puferfsh. Immunohistochemistry using multiple antibodies and in situ hybridization analysis revealed that Cyp19a1b colocalizes with luteinizing hormone (LH) in pituitary cells. Furthermore, Esr1 was localized in the nuclei of all hormone-producing cells, whereas Esr2b was localized only in the nuclei of Cyp19- and LH-positive cells. The administration of an aromatizable androgen (T) or oestrogen (E2) to reproductively inactive females induced LH synthesis in vivo. We prepared spheroids from pituitary cells to investigate the role of local E2 in LH synthesis in vitro. Immunohistochemical analysis of spheroids showed that T-induced LH synthesis could be blocked by an aromatase inhibitor and/or an ER antagonist but not an AR antagonist. Taken together, these fndings suggest that LH synthesis is initiated in cyp19a1b-, esr1-, and esr2b-expressing cells at the onset of puberty under the control of steroidal feedback, and both feedback and local oestrogen may be involved in controlling LH synthesis in these cells..
3. Sanny David Pachenco Lumayno, Kohei Ohta, Akihiko Yamaguchi, Michiya Matsuyama, Molecular characterisation and reporter gene assay of three GnRH isoforms and two GnRH receptors of a Clupeiform fish, Japanease sardine, Sardinops sagax melanostictus (Temminck & Schhlegel, 1846), Asian Fisheries Science, 35, 26-43, 2022.01.
4. S.Selvaraji, B Ahilan, A Yamaguchi, M Matsuyama, Multiplicity of gonadotropin-releasing hormone in fish, Journal of Entomology and Zoology Studies, 9, 3, 352-361, 2021.12.
5. Ohga,H., Adachi,H., Yamaguchi,A., Matsuyama,M, Kiss1 hexadecapeptide directly regulates gonadotropin-releasing hormone 1 in the scombroid fish, chub mackerel, BIOLOGY OF REPRODUCTION, 96, 376-388, 2017.02.
6. Lumayno, SDP, Ohga,H., Selvaraji,S., Nyuji,M., Yamaguchi, A., Matsuyama,M., Molecular characterization and functional analysis of pituitary GnRH receptor in a commercial scombroid fish, chub mackerel (Scomber japonicus)., GENERAL AND COMPARATIVE ENDOCRINOLOGY, 247, 143-151, 2017.01.
7. Ohga, H., Hirata, D., Nagano, N., Yamaguchi, A., Matsuyama, M., Possible role of the leptin system in controlling puberty in the male chub mackerel, Scomber japonicas.
Comp. Biochem. Physiol., GENERAL AND COMPARATIVE ENDOCRINOLOGY , 203, 159-166, 2016.09.
8. Ohga,H., Matsumori,K., Kodama,R., Kitano,H., Nagano, N., Kato,K., Yamaguchi, A., Michiya Matsuyama, Two leptin genes and a leptin receptor gene of female chub mackerel (Scomber japonicus): Molecular cloning, tissue distribution and expression in different obesity indices and pubertal stages, GENERAL AND COMPARATIVE ENDOCRINOLOGY, 10.1016/j.ygcen.2015.06.002, 222, 88-98, 2015.10.
9. Selvaraj,S., Kitano,H., Ohga,H., Yamaguchi,A., Matsuyama,H., Expression changes of mRNAs encoding kisspeptins and their receptors and gonadotropin-releasing hormones during early development and gonadal sex differentiation periods in the brain of chub mackerel (Scomber japonicus)., GENERAL AND COMPARATIVE ENDOCRINOLOGY , 222, 20-32, 2015.05.
10. Selvaraj,S., Ohga,H., Nyuji, M., Kitano,H., Nagano,N., Yamaguchi, A., Matsuyama,M., Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus)., Aquaculture Research, 46, 1866-1877, 2015.05.
11. Ohga, H., Adachi,H., Matsumori, K., Kodama,R., Nyuji, M., Selvaraji,S., Kato,K., Yamaguchi, A., Matsuyama, M., mRNA levels of kisspeptins, kisspeptin receptors, and GnRH1 in the brain of chub mackerel during puberty., Comp. Biochem. Physiol. Part A., 222, 88-98, 2015.06.
12. Yui Imanaga, Mitsuo　Nyuji, Masafumi　Amano, Akiyoshi　Takahashi, Hajime Kitano, Akihiko Yamaguchi, Michiya Matsuyama, Characterization of gonadotropin-releasing hormone and gonadotropin　in jack mackerel (Trachurus japonicus): Comparative gene expression
analysis with respect to reproductive dysfunction in captive and wild fish, Aquaculture, http://dx.doi.org/10.1016/j.aquaculture.2014.03.003, 428-429, 226-235, 2014.04, To better understand the physiologicalmechanisms underlying reproductive dysfunction, such as impaired vitellogenesis
and final oocytematuration, we assessed endocrinological differences between captive and wild female jack
mackerel (Trachurus japonicus). The presence of three gonadotropin-releasing hormone (GnRH) peptides was immunologically
evaluated in jack mackerel brain tissues. Full-length cDNAs encoding GnRHs (gnrh1, gnrh2, and
gnrh3) and gonadotropin subunits (fshb, lhb, and gpa) were cloned, sequenced, and quantitatively assayed. Of the
captive females, 60% failed to undergo vitellogenesis, displaying immature (IM) or atretic oocytes, whereas 80%
of wild females were captured during late vitellogenesis (LV) or ovulation (OV). The gnrh1 expression was significantly
lower in captive fish than in wild LV and OV fish, while there were no significant differences in the expression
of gnrh2 or gnrh3. The expression of fshb was lower in captive IMfish than in wild LV fish, but no significant differences
were observed between the captive IM and LV individuals. The lhb expression was elevated in the wild LV and
OV fish, and gpa expression was greatest in the wild OV fish. Serum estradiol-17β levels were significantly lower in
captive IMfish than in captive LV fish. The results indicate that captive-rearing stress may impair vitellogenesis and
negatively influence the transcription of gnrh1 in the brain and GtH synthesis in the pituitary.
13. Nyuji,M., Kodama,R., Kato,K., Yamamoto,S., Yamaguchi, A., Michiya Matsuyama, Gonadal development and gonadotropin gene expression during puberty in cultured Chub mackerel (Scomber japonicus). , Zoological Science, 31, 398-406 , 2014.05.
14. Hirofumi　Ohga, Selvaraji　Sethu, Yui　Imanaga, Hayato Adachi, Yui Imanaga, Akihiko Yamaguchi, Michiya Matsuyama, Functional analysis of kisspeptin peptides in adult immature chub mackerel (Scomber japonicus) using an intracerebroventricular administration method., Neuroscience Letters, 10.1016/j.neulet.2013.12.072 , 2014.01, In vertebrates (including teleosts), the pivotal hierarchical factor in the control of gonadotropin secretion is the hypothalamic gonadotropin-releasing hormone (GnRH) decapeptide, which regulates the release of pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Recently, kisspeptins encoded by the Kiss1 gene have been shown to act as upstream endogenous regulators of GnRH neurons in mammals. The chub mackerel (Scomber japonicus) brain expresses two kiss genes (kiss1 and kiss2) that show sexually dimorphic expression profiles during the seasonal gonadal cycle. In the present study, we evaluated the biological potency of kisspeptin peptides to induce transcriptional changes in gnrh1 (hypophysiotropic GnRH form in this species), fshβ and lhβ during the immature stage of adult chub mackerel (2+ years old). Synthetic Kiss1 pentadecapeptide (Kiss1-15) or Kiss2 dodecapeptide (Kiss2-12) at a dose of 100ng were administered into the intracerebroventricular (ICV) region, and brains were sampled at 6 and 12h post-injection. In female fish, gnrh1 levels decreased in the presence of both kisspeptin peptides at 12h post-injection. No significant variation was observed in male fish. In contrast, ICV administration of Kiss2-12 (but not Kiss1-15) significantly increased fshβ and lhβ mRNAs at 12h post-injection compared to a saline injected control in both sexes. These results suggested that synthetic Kiss2-12 could induce transcriptional changes in gnrh1 and gths..
15. Zahid Parvez Sukhan, Hajime Kitano, Sethu Selvaraj, Michio Yoneda, Akihiko Yamaguchi, Michiya Matsuyama, Identification and Distribution of Three Gonadotropin-Releasing Hormone (GnRH) Isoforms in the Brain of a Clupeiform Fish, Engraulis japonicus. , ZOOLOGICAL SCIENCE , 10.2108/zsj.30.1081 , 30 , 12 , 1081-1091, 2013.12, To gain a better understanding of the reproductive endocrinology of a primitive order clupeiform fish (Japanese anchovy, Engraulis japonicus), cDNAs encoding three gonadotropin-releasing hormone (GnRH) isoforms were isolated from the brain, and their distribution was analyzed using insitu hybridization (ISH). The three GnRH isoforms include GnRH1 (herring GnRH), GnRH2 (chicken GnRH-ll) and GnRH3 (salmon GnRH), and their full-length cDNAs encode 88, 86, and 89 deduced amino acids (aa), respectively. Alignment analysis of Japanese anchovy GnRH isoforms showed lower identities with other teleost fish. The major population of GnRH1 neurons was localized in the ventral telencephalon (VT) and nucleus preopticus (NPO) of the preoptic area (POA) with minor population in the anterior olfactory bulb (OB). GnRH2 neurons were restricted to the midbrain tegmentum (MT), specific to the nucleus of the medial longitudinal fasciculus (nMLF). GnRH3 neurons were localized in the olfactory nerve (ON), ventral OB, and transitional area between OB and ON. Interestingly, GnRH1 neurons were also localized in the olfactory bulb, in addition to its major population in the preoptic area. These results indicate the differential distribution of three GnRH isoforms expressed in the brain of the Japanese anchovy..
16. Sethu Selvaraj, Hirofumi Ohga, Mitsuo Nyuji, Hajime Kitano, Naoki Nagano, Akihiko Yamaguchi, Michiya Matsuyama, Effects of synthetic kisspeptin peptides and GnRH analogue on oocyte growth and circulating sex steroids in prepubertal female chub mackerel (Scomber japonicus) , Aquaculture Research , 10.1111/are.1342 , 2013.11, In recent years, kisspeptin peptides, encoded by kiss genes have been used to manipulate reproductive processes in farmed animals, including fish. Our previous studies demonstrated that the chub mackerel brain expresses kiss1 and kiss2 and intramuscular injection of synthetic Kiss1 pentadecapeptide (Kiss1-15) but not Kiss2 dodecapeptide (Kiss2-12) accelerates spermatogenesis in prepubertal male chub mackerel (Scomber japonicus). In the present study, we evaluated their effects in prepubertal female chub mackerel. The gonadosomatic index (GSI) values of experimental fish did not showed any significant changes. Condition factor (CF) values increased significantly in Kiss1-15 treated fish, in comparison to control and GnRH analogue (GnRHa) injected fish. Histologically, only perinucleolar oocytes were found in all experimental fish. However, Kiss and GnRHa treated fish showed a significant increase in the perinucleolar oocyte diameter, in comparison to the control fish. Gene expression analyses revealed decreased expression of gnrh1 in the telencephalon-preoptic region of the brain of Kiss2-12 and GnRHa injected fish, in comparison to control fish. In contrast, GnRHa injected fish exhibited higher levels of fshβ in the pituitary, with no changes in the levels of lhβ among different treatments. Levels of circulating sex steroids, testosterone and estradiol-17β were significantly higher in Kiss1-15 injected fish, in comparison to control fish. These results indicate that synthetic kisspeptin peptides and GnRHa can induce oocyte growth in prepubertal female chub mackerel..
17. Hirofumi Ohga, Yoichiro Fujinaga, Sethu Selvaraj, Hajime Kitano, Mitsuo Nyuji, Akihiko Yamaguchi, Michiya Matsuyama, Identification, characterization, and expression profiles of two subtypes of kisspeptin receptors in a Scombroid fish (chub mackerel)., General and Comparative Endocrinology , 10.1016/j.ygcen.2013.07.016 , 2013.08, The kisspeptin receptor (Kiss1R) is a cognate receptor for kisspeptin (Kiss), and this Kiss-Kiss1R system has been shown to regulate seasonal reproduction in vertebrates. Our previous study found the chub mackerel (Scomber japonicus) brain expresses both kiss1 and kiss2 and exhibits sexually dimorphic changes during the seasonal reproductive cycle. The present study cloned two subtypes of kissr from the chub mackerel brain, and their signal transduction pathways to Kiss1 and Kiss2 were characterized in a mammalian cell line. Results of identification showed that kissr1 and kissr2 mRNAs encode 369 and 378 deduced amino acids, respectively, and share 52% similarity in amino acid sequences. In vitro functional analysis revealed that chub mackerel Kiss receptor signals are also preferentially transduced via the protein kinase C (PKC) rather than protein kinase A (PKA) pathway. Synthetic chub mackerel Kiss1-15 and Kiss2-12 peptides showed the highest potency for the activation of KissR1 and KissR2, respectively, stronger than their corresponding Kiss-10 peptides. Tissue distribution analyses indicated that both genes are highly expressed in the brain and that only kissr2 mRNA is expressed in the pituitary of both sexes. Unexpectedly, both kissr1 and kissr2 mRNAs were detected only in the testes. Seasonal expression changes showed higher expression levels of both kissr1 and kissr2 mRNAs in the brain of females during the early vitellogenic period; however, no significant differences were found in the brain of males. Pituitary kissr2 mRNA levels showed no significant variations. In the testes, the kissr1 mRNA expression level increased dramatically at spermiation compared with the immature and post-spawning periods. However, kissr2 mRNA levels in the testes did not vary significantly at different testicular stages. These results suggest that both kissr1 and kissr2 likely participate in the seasonal ovarian development of females, and thus in males, we propose a paracrine or autocrine role for kissr1 in testicular development..
18. Sethu Servaraj, Hirofumi Ohga, Hajime Kitano, Akihiko Yamaguchi, Michiya Matsuyama, Peripheral administration of kiss1 pentadecapeptide induces gonadal development in sexually immature adult scombroid fish., ZOOLOGICAL SCIENCE , 10.2108/zsj.30.44, 2013.06, Kisspeptins have emerged as potent regulators of the reproductive brain-pituitary-gonad (BPG) axis. Our previous study demonstrated that the brain of the chub mackerel (Scomber japonicus), a scombroid fish, expresses two kisspeptin-encoding genes, kiss1 and kiss2, and exhibits sexually dimorphic expression profiles. Recent studies strongly suggest that teleost Kiss1 and Kiss2 precursors produce mature Kiss1-pentadecapeptides (Kiss1-15) and Kiss2-dodecapeptides (Kiss2-12), respectively. In light of the above, the present study evaluated the potency of synthetic peptides of Kiss1-15, Kiss2-12, and a GnRH analog (GnRHa) on inducing gonadal development in sexually immature adult chub mackerel. Synthetic peptides were administered subcutaneously through mini-osmotic pumps. On day 45 post-administration, gonadosomatic index (GSI) values (%) of male fish treated with Kiss1-15 (1.82) significantly increased in comparison to initial control (0.33), final control (0.49), Kiss2-12 (0.24), and GnRHa (1.13)-treated fish. Interestingly, the testis of all Kiss1-15 treated fish revealed spermiation, and were full of spermatozoa. These fish showed significantly higher levels of pituitary fshβ and Ihβ mRNAs and circulating 11-ketotestosterone. GnRHa treated fish also revealed the presence of few spermatozoa in the testis. In females, no significant changes in GSI values were found between treatments; however, Kiss1-15- and GnRHa-treated fish showed prominent signs of vitellogenic onset, with many early yolk oocytes in their ovaries. Interestingly, Kiss1-15-treated fish exhibited higher levels of pituitary fshβ and circulating estradiol-17β. These results indicate that peripheral administration of Kiss1-15 and GnRHa can induce gonadal development in sexually immature chub mackerel.
19. Sethu Selvaraj, Hirofumi Ohga, Mitsuo Nyuji, Hajime Kitano, Naoki Nagano, Akihiko Yamaguchi, Michiya Matsuyama, Subcutaneous administration of Kiss1 pentadecapeptide accelerates spermatogenesis in prepubertal male chub mackerel (Scomber japonicus)., Comparative biochemistry and physiology. Part A, Molecular & integrative physiology , 10.1016/j.cbpa.2013.06.007, 2013.06, Kisspeptins, encoded by kiss genes have emerged as critical regulator of reproductive function in vertebrates. Our previous studies demonstrated that the chub mackerel (Scomber japonicus) brain expresses kiss1 and kiss2 and peripheral administration of synthetic Kiss1 pentadecapeptide (Kiss1-15) but not Kiss2 dodecapeptide (Kiss2-12) induces spermiation in sexually immature adult chub mackerel. In the present study, we evaluated the potency of Kiss1-15, Kiss2-12, and GnRH analogue (GnRHa) to induce pubertal onset in prepubertal chub mackerel. Peptides were administered through subcutaneous injection for three times (bi-weekly) over 6 weeks. Interestingly, gonadosomatic index (GSI) of Kiss1-15 treated fish increased significantly in comparison to other treatments. Histologically, 66.7% of Kiss1-15 treated fish exhibited presence of spermatozoa (SPZ) in the testes with only 28.6 % of GnRHa treated fish. However, Kiss2-12 treated fish showed only spermatocytes (SC) as the advanced germ cells in the testes. In contrast, only spermatogonia (SPG) were observed in the testes of control fish. Changes in the number of testicular germ cells among treatments revealed a significantly higher number of SC, spermatids and SPZ in the Kiss1-15 treated fish. Gene expression analyses revealed no significant changes in gnrh1 in the telencephalon-preoptic region of the brain, including fshβ and lhβ in the pituitary of experimental fish. However, GnRHa treated fish showed significantly higher lhβ expression. Levels of sex steroids, 11-ketotestosterone and estradiol-17β were significantly higher in Kiss1-15 treated fish. These results indicate application of Kiss1-15 peptides for accelerating pubertal onset in chub mackerel.
20. Mitsuo Nyuji, Hajime Kitano, Akio Shimizu, JAE MAN LEE, takahiro kusakabe, Akihiko Yamaguchi, Michiya Matsuyama, Characterization, Localization, and Stage-Dependent Gene Expression of Gonadotropin Receptors in Chub Mackerel (Scomber japonicus) Ovarian Follicles, BIOLOGY OF REPRODUCTION, 10.1095/biolreprod.112.107292, 88, 148, 1-14, 2013.05.
21. ＠Akihiko Yamaguchi, ＃Miho Iwatani, ＃Mariko Ogawa, ＃Hajime Kitano,＠Michiya Matsuyama, In vitro characterization of the RS motif in N-terminal head domain of goldfish germinal vesicle lamin B3 necessary for phosphorylation of the p34cdc2 target serine by SRPK1, FEBS Open Bio, 10.1016/j.fob.2013.03.003, 3, 165-176, 2013.03, The nuclear envelopes surrounding the oocyte germinal vesicles of lower vertebrates (fish and frog)
are supported by the lamina, which consists of the protein lamin B3 encoded by a gene found also in
birds but lost in the lineage leading to mammals. Like other members of the lamin family, goldfish
lamin B3 (gfLB3) contains two putative consensus phosphoacceptor p34cdc2 sites (Ser-28 and Ser-398)
for the M-phase kinase to regulate lamin polymerization on the N- and C-terminal regions flanking a
central rod domain. Partial phosphorylation of gfLB3 occurs on Ser-28 in the N-terminal head domain
in immature oocytes prior to germinal vesicle breakdown, which suggests continual rearrangement of
lamins by a novel lamin kinase in fish oocytes. We applied the expression-screening method to isolate
lamin kinases by using phosphorylation site Ser-28-specific monoclonal antibody and a vector encoding
substrate peptides from a goldfish ovarian cDNA library. As a result, SRPK1was screened as a prominent
lamin kinase candidate. The gfLB3 has a short stretch of the RS repeats (9-SRASTVRSSRRS-20) upstream
of the Ser-28, within the N-terminal head. This stretch of repeats is conserved among fish lamin B3 but
is not found in other lamins. In vitro phosphorylation studies and GST-pull down assay revealed that
SRPK1 bound to the region of sequential RS repeats (9–20) with affinity and recruited serine into the
active site by a grab-and-pull manner. These results indicate SRPK1may phosphorylate the p34cdc2 site
in the N-terminal head of GV-lamin B3 at the RS motifs,which have the general property of aggregation..
22. Mitsuo Nyuji, Kazuki Fujisawa, Yui Imanaga, Hajime Kitano, Akihiko Yamaguchi, Michiya Matsuyama, GnRHa-induced spawning of wild-caught jack mackerel Trachurus japonicus , Fisheries Science, 10.1007/s12562-013-0599-4, 12, 2013.02, The jack mackerel Trachurus japonicus is a
key commercially exploited fish species in Japan. The
rearing experiment often provides information that is useful
for understanding the reproductive characteristics of
wild stocks; however, there has been no study on spawning
in captive T. japonicus. In the study reported here, we
induced spawning in T. japonicus caught in the wild by
hook and line. Females with fully vitellogenic oocytes and
males during spermiation were selected by gonadal biopsy
and injected with gonadotropin-releasing hormone analog
(GnRHa) mixed in molten coconut butter. This treatment
was performed four times in different groups of four
females and five to eight males, and each group was
maintained in a 3-m3 concrete tank. We observed the first
spawning at 1 or 2 days post-injection and collected
between 41,690 and 149,450 eggs. Spawning was recorded
on 18 consecutive days in one experiment and for 3 days
continuously in the other experiments. In the former,
spawning ended when the water temperature reached 23 C
and occurred mainly between 2100 and 2400 hours. These
results indicate that GnRHa-induced spawning may be
useful for evaluating the reproductive characteristics of
T. japonicus and obtaining fertilized eggs to conduct larval
experiments..
23. Kitano, H., Irie, S., Ohta, K., Hirai, T., Yamaguchi, A., Matsuyama M., Molecular cloning of two gonadotropin receptors and their distinct mRNA expression profiles indaily oogenesis of wrasse Pseudolabrus sieboldi, Geneal and comparative endocrinology, 10.1016/j.ygcen.2011.03.012, 172, 268-276, 2011.03.
24. Kitano, H., Irie, S., Yamaguchi, A., Matsuyama, M, Diurnal dynamics of S-phase entry of germ cells in the secondary testis of the Bambooleaf Wrasse(Pseudolabrus sieboldi), Journal of Experimental Zoology, 315, 232-241, 2011.01.
25. Kaneko, T., Murayama, E., Kurio, H., Yamaguchi, A. and Iida, H., Characterization of Spetex-1, a new component of satellite fibrils associated with outer dense fibers in the middle piece of rodent sperm flagella. ,, Molecular Reproduction and Development,, 77, 363-372, 2010.04.
26. Selvaraji,S.,Kitano,H., Fujinaga, Y., Ohga, H., Yoneda, M., Yamaguchi, A., Shimizu, A., Matsuyama, M., Molecular characterization, tissue distribution, and mRNA expression profiles of two kiss genes in the adult male and female chub mackerel (Scomber japonicus) during differnt gonadal stages, General and comparative endocrinology, 10.1016/j.ygeen.2020.07.011, 169, 28-38, 2010.07.
27. Kyung-Hoon Lee, Akihiko Yamaguchi*, Harunur Rashid, Kazushi Kadomura, Susumu Yasumoto, Michiya Matsuyama, Estradiol-17β treatment induces intersexual gonadal development in the pufferfish, Takifugu rubripes, Zoological Science, Vol26.639-645, 2009.10.
28. Lee, K-H., Yamaguchi, A.*, Rashid-H., Kadomura, K., Yasumoto,S. and Matsuyama,M. , Germ cell degeneration in high-temperature treated pufferfish, Takifugu rubripes
, Sexual Development, Vol3 ,No4, 225-232., 2009.09.
29. Shiraishi T., Suvarna,D.K., Katoh, Y., Nyuji, M., Yamaguchi, A., Matsuyama, M., Spawning frequency of the Tsushima Current Subpopulation of chub mackerel Scomber japonicus off kyushu, Japan, Fisheries Science, 75:649-655(2009), 2009.06.
30. Chinari Onitsuka, Akihiko Yamaguchi, Hikoichirou Kanamaru, Shin Oikawa, Tatsusuke Takeda, Michiya Matsuyama, Molecular Cloning and Expression Analysis of a GnRH-Like Dodecapeptide in the Swordtip Squid, Loligo edulis
, Zoological Science, Volume 26, Issue 3, 203–208
, 2009.03.
31. Kohei Ohta, Takayuki Mine, Akihiko Yamaguchi, Michiya Matsuyama, Sexually dimorphic expression of pituitary glycoprotein hormones in a sex-changing fish, (Pseudolabrus sieboldi), Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, Volume 309A, Issue 9, Date: November 2008, Pages: 534-541, 2008.11.
32. K. Ohta, M. Hirano, T. Mine, H. Mizutani, A. Yamaguchi, M. Matsuyama, Body color change and serum steroid hormone levels throughout the process of sex change in the adult wrasse, Pseudolabrus sieboldi, Marine Biology, 153, 843-852 , 2008.11.
33. Rashid, H., Kitano H., Lee, K.H., Nii, S., Shigematsu, T., Kadomura, K., Yamaguchi A., Matsuyama, M., Ｆｕｇｕ(Takifugu rubripes) Sexual Differntiation: CYP19 Regulation and Aromatase Inhibitor Induced Testicular Development, Sexual Development, 1:311-322, 2007.11.
34. Yamaguchi, A., Katsu,Y., Matsuyama, M., Yoshikuni, M., Nagahama,Y., Phosphorylation of the p34cdc2 target site on goldfish germinal vesicle lamin B3 before oocyte maturation, European Journal of Cell Biology, 85, 501-517, 2006.06.
35. Yamaguchi, A., Lee,K-H., Fujimoto, H., kadomura,K., Yasumoto,S.,Matsuyama, M., Expression of DMRT gene and its roles in early gonadal development of Japanese pufferfish Takifugu rubripes, Comarative Biochemistry and Physiology Part D: Genomics and Proteomics, 1, 59-68, 2006.01.
36. Shiraishi,T., Ohta,K., Yamaguchi,A., Yoda,M., Chuda,H., Matsuyama,M., Reproductive parameters of the chub mackerel Scomber japonicus estimated from human chorionic gonadotropin-induced final oocyte maturation and ovuloation in captivity, Fisheries science, 10.1111/j.1444-2906.2005.00997.x, 71, 3, 531-542, 71, 531-542, 2005.01.
37. Matsuyama, M., Shiraishi, T., Sundaray,J.K., Rahaman, M.S. Ohata, K., Yamaguchi, A., Steroidogenesis in ovarian follicles of Chub Mackerel, Scomber japonicus, Zoological Science, 10.2108/zsj.22.101, 22, 1, 101-110, 22,101-110, 2005.01.
38. Jiang, JQ., Wang,　DS., Senthilkumaran, B., Kobayashi,　T., Kobayashi,　H K., Yamaguchi, A., Ge,　W., Young G and Nagahama，Y., Isolation, characterization and expression of 11β-hydroxysteroid dehydrogenase　type 2 cDNAs from the testes of Japanese eel (Anguilla japonica) and Nile tilapia (Oreochromis niloticus)., J.Mol.Endocrinology., 31,305-315, 2003.01.
39. Rahman, M.A., Ohta, K., Chuda, H., Yamaguchi, A. and Matsuyama, M., Steroid　hormones and their synthetic pathways in the vitellogenic ovarian follicles of yellowtail, Seriola quinqueradiata., J. Fac. Agr., Kyushu univ., 46, 2, 311-319, 46 (2) 311-319., 2002.01.
40. Ohta，K.,　Yamaguchi，S．，Yamaguchi, A．，Okuzawa，K.,　Gen，K.,　Kagawa，H. and Matsuyama, M., Biosynthesis of steroids in ovarian follicles of red seabream, Pagrus major (Sparidae, Teleostei) during final oocyte maturation and the relative effectiveness of steroid metabolites for germinal vesicle break down in vitro., Comp. Biochem. Phys. Part B., 10.1016/S1096-4959(02)00106-9, 133, 1, 45-54, 133, 45-54., 2002.01.
41. Ohta, K.,　Yamaguchi, S., Yamaguchi, A., Okuzawa, K.,　Gen，K.,　Kagawa, H. and Matsuyama, M., Biosynthesis of estradiol-17β in the ovrian follicles of the red seabream Pagrus major during vitellogenesis., Fish. Sci., 10.1046/j.1444-2906.2002.00477.x, 68, 3, 680-687, 68, 680-687., 2002.01.
42. Ohta, K., Mine, T., Yamaguchi, A. and Matsuyama, M., Steroidogenic pathway to estradiol-17b synthesis in the ovarian follicles of the Protogynus Wrasse, Pseudolabrus sieboldi., Zool.Sci., 10.2108/zsj.18.937, 18, 7, 937-945, 18, 937-945., 2001.01.
43. Yamaguchi, A. and Nagahama, Y., Somatic lamins in germinal vesicles of goldfish (Carassius auratus) oocytes., Cell Struc. Func., 26, 693‐703., 2001.01.
44. Yamaguchi, A., Yamashita, M., Yoshikuni, M. and Nagahama, Y., Identification and molecular cloning of germinal vesicle lamin B3 in goldfish (Carassius autratus) oocytes., Eur. J. Biochem., 268, 932-939., 2001.01.
45. Furukawa, K., Inagaki, H., Naruse, T., Tabata, S., Tomida, T., Yamaguchi, A., Yoshikuni, M., Nagahama, Y. and Hotta, Y., cDNA cloning and functional characterization of a meiosis-specific protein (MNS1) with apparent nuclear association., Chromosome Res., 2, 99-113., 1994.01.
46. Tokumoto, M., Yamaguchi, A., Nagahama, Y. and Tokumoto, T., Identification of　the goldfish 20S proteasome β6 subunit bound to nuclear matrix., FEBS Lett., 472, 62-66., 2000.01.
47. Yamashita, M., Fukada, S., Yoshikuni, M., Bulet, P., Hirai, T., Yamaguchi, A., Yasuda, H., Ohba, Y. and Nagahama, Y., M-phase-specific histone H1 kinase in fish oocytes: its purification, components and biochemical properties., Eur. J. Biochem., 205, 537-543., 1992.01.
48. Yamashita, M., Fukada, S., Yoshikuni, M., Bulet, P., Yamaguchi, A., Lou, Y.H., Zhao, Z. and Nagahama, Y., Purification and characterization of maturation-promoting factor in fish., Develop. Biol., 149, 8-15., 1992.01.
49. Yamaguchi, A., Yamashita, M., Yoshikuni, M., Hotta,Y., Nurse, P. and Nagahama, Y., Involvement in meiotic prophase of H1 kinase and p34cdc2 homologues in lily (Lilium longiflorum) microsporocytes., Develop. Growth Differ., 33, 625-632., 1991.01.


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