Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Yoshitaka Kobayakawa Last modified date:2019.05.29

Professor / Division for Experimental Natural Science / Division for Experimental Natural Science / Faculty of Arts and Science

1. Hiroyuki J. Kanaya, Yoshitaka Kobayakawa, Taichi Q. Itoh, Hydra vulgaris exhibits day-night variation in behavior and gene expression levels, Zoological Letters, 10.1186/s40851-019-0127-1, 5, 1, 2019.03, Background: Day-night behavioral variation is observed in most organisms, and is generally controlled by circadian clocks and/or synchronization to environmental cues. Hydra species, which are freshwater cnidarians, are thought to lack the core clock genes that form transcription-translation feedback loops in clock systems. In this study, we examined whether hydras exhibit diel rhythms in terms of behavior and gene expression levels without typical clock genes. Results: We found that the total behavior of hydras was elevated during the day and decreased at night under a 12-h light-dark cycle. Polyp contraction frequency, one component of behavior, exhibited a clear diel rhythm. However, neither total behavior nor polyp contraction frequency showed rhythmic changes under constant light and constant dark conditions. To identify the genes underlying diel behavior, we performed genome-wide transcriptome analysis of hydras under light-dark cycles. Using three different analytic algorithms, we found that 380 genes showed robust diel oscillations in expression. Some of these genes shared common features with diel cycle genes of other cnidarian species with endogenous clock systems. Conclusion: Hydras show diel behavioral rhythms under light-dark cycles despite the absence of canonical core clock genes. Given the functions of the genes showing diel oscillations in hydras and the similarities of those genes with the diel cycle genes of other cnidarian species with circadian clocks, it is possible that diel cycle genes play an important role across cnidarian species regardless of the presence or absence of core clock genes under light-dark cycles..
2. Ryo Miyokawa, Takuya Tsuda, Hiroyuki J Kanaya, Junko Kusumi, Hidenori Tachida, Yoshitaka Kobayakawa, Horizontal Transmission of Symbiotic Green Algae Between Hydra Strains, Biological Bulletin, 10.1086/699705, 235, 2, 113-122, 2018.10, Some hydra strains belonging to the vulgaris group show a symbiotic relationship with green algae Chlorococcum sp. The symbiotic green algae can escape from the host polyps and can form swimming zoospores (which have two flagella) in culture solution. We observed that co-culture with the symbiotic polyps caused horizontal transmission of the symbionts into some non-symbiotic hydra strains that have no symbionts in nature and that belong not only to the vulgaris group but also to other hydra species groups. Although most of the horizontal transmission has ended in transient symbioses, a newly formed symbiosis between the symbiotic Chlorococcum sp. and strain 105 of Hydra vulgaris (Hydra magnipapillata) has been sustained for more than five years and has caused morphological and behavioral changes in the host polyps. We named this strain 105G. The asexual proliferation rate by budding increased under light conditions, although the feeding activity decreased and the polyp size was reduced in strain 105G. This new symbiosis between Chlorococcum sp. and strain 105G of H. vulgaris provides us with an intriguing research system for investigating the origin of symbiosis..
3. Kobayakawa Y., SYMBIOSIS BETWEEN GREEN ALGAE AND HYDRA” in “ALGAE and CYANOBACTERIA SYMBIOSES, ALGAE and CYANOBACTERIA SYMBIOSES” edited by Martin Grube, Lucia Muggia,and Joseph Seckbach, World Scientific, 2017.02.
4. Hitomi Kawaida, Kohki Ohba, Yuhki Koutake, Hiroshi Shimizu, Hidenori Tachida, Yoshitaka Kobayakawa, Symbiosis between hydra and chlorella: Molecular phylogenetic analysis and experimental study provide insight into its origin and evolution, Molecular Phylogeny and Evolution,, 66, 906-914, 2013.02, Although many physiological studies have been reported on the symbiosis between hydra and green algae, very little information from a molecular phylogenetic aspect of symbiosis is available. In order to understand the origin and evolution of symbiosis between the two organisms, we compared the phy- logenetic relationships among symbiotic green algae with the phylogenetic relationships among host hydra strains. To do so, we reconstructed molecular phylogenetic trees of several strains of symbiotic chlorella harbored in the endodermal epithelial cells of viridissima group hydra strains and investigated their congruence with the molecular phylogenetic trees of the host hydra strains. To examine the species specificity between the host and the symbiont with respect to the genetic distance, we also tried to intro- duce chlorella strains into two aposymbiotic strains of viridissima group hydra in which symbiotic chlo- rella had been eliminated in advance. We discussed the origin and history of symbiosis between hydra and green algae based on the analysis..
5. Hitomi Kawaida, Hiroshi Shimizu, Toshitaka Fujisawa, Hidenori Tachida, Yoshitaka Kobayakawa, Molecular phylogenetic study in genus Hydra, Gene, 10.1016/j.gene.2010.08.002, 468, 30-40, 2010.08.
6. Toshio Takahashi, Osamu Koizumi, Eisuke Hayakawa, Sumiko Minobe, Rinako Suetsugu, Yoshitaka Kobayakawa, Thomas C. G. Bosch, Charles N. David, Toshitaka Fujisawa, Further characterization of the PW peptide family that inhibits neuron differentiation in Hydra, Developmant Genes and Evolution, 219, 119-129, 2009.02.
7. Amimoto Y., Kodama R., Kobayakawa Y., Foot formation in Hydra: A novel gene, anklet, is involved in basal disk formation., Mechanisms of Development, 123, 352-361., 2006.01.
8. Takahashi T. , Kobayakawa Y ., Muneoka Y., Fujisawa Y , Mohri S, Hatta M., Shimizu H., Fujisawa T., Sugiyama T., Takahara M., Yanagi K., Koizumi O., Identification of a new member of the GLWamide peptide family:physiological activity and cellular localization in cnidarian polyps., Comparative Biochemistry and Physiology Part B, 10.1016/S1096-4959(03)00088-5, 135, 2, 309-324, 135,309-324, 2003.01.
9. Kobayakawa Y & Kodama R., Foot formation in Hydra: Commitment of the basal disk cells in the lower peduncle., Develop. Growth Differ, 44, 6, 517-526, 44,517-526, 2002.12.
10. Nagano T., Ito Y., Tashiro K., Kobayakawa Y. & Sakai M., Dorsal induction from dorsal vegetal cells in Xenopus occurs after mid-blastula transution., Mechanisms of Development, 10.1016/S0925-4773(00)00251-3, 93, 1-2, 3-14, 93,3-14, 2000.01.
11. Takahashi T., Koizumi O., Ariura Y., Romanovitch A., Bosch T.C.G., Kobayakawa Y., Mohri S., Bode H.R., Yum S., Hatta M. & Fujisawa T., A novel neuropeptide, Hym-355, positively regulates neuron differentiation in Hydra., Development, 127, 5, 997-1005, 127,997-1005, 2000.01.
12. Hatta M., Sakaguchi M., Kobayakawa Y., Kishimoto Y. & Koizumi O., Identification of a homolog of actin-binding protein, ABP-280, localized at epithelial cell-cell boundaries in Hydra., Zoological Science, 10.2108/zsj.16.439, 16, 3, 439-443, 16,439-443, 1999.01.
13. Yum S., Takahashi T., Koizumi O., Ariura Y., Kobayakawa Y., Mohri S. & Fujisawa T., A novel neuropeptide, Hym-176 induces contraction of the ectodermal muscle in Hydra., Biochem. Biophys. Res. Comm., 10.1006/bbrc.1998.8831, 248, 3, 584-590, 248,584-590, 1999.01.