2018 Fiscal Year Final Research Report
Studies on physiological functions of saccus vasculosus in Japanese eel
| Project/Area Number |
16K07846
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Aquatic bioproduction science
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| Research Institution | University of Miyazaki |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
内田 勝久 宮崎大学, 農学部, 教授 (50360508)
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| Research Collaborator |
MIYANISHI hiroshi
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | ニホンウナギ / 血嚢体 / 光受容 / 成熟制御機構 / 成熟誘導技術 / シラスウナギ / 種苗生産 |
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| Outline of Final Research Achievements |
The physiological function of Japanese eel saccus vasculosus (SV) has long been unknown. In this study, to clarify the photoperiodic and the physiological roles of SV in the Japanese eel, we examined the presence of rhodopsin family genes and key genes regulating seasonal reproduction in the SV. By means of real time quantitative PCR, we found that photoreceptors, such as short wavelength-sensitive opsin 2 (sws2, blue sensitive) was highly expressed in the SV and increased from summer to winter in male eels reared in the outside pond. Moreover, we found that iodothyronine 5'-deiodinase (dio2), tshβ, and gpα expressed in the SV and these factors also increased during the process of puberty. We also demonstrated that removal of SV by surgical surgery decreased gene expression of these factors and depressed the development of oocytes. These results indicate that saccus vasculosus has important physiological function of photoreceptor and the sexual maturation in Japanese eel.
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| Free Research Field |
魚類繁殖生理学分野
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| Academic Significance and Societal Importance of the Research Achievements |
シラスウナギの大量種苗生産技術を開発するためには安定的に簡便な方法で受精卵を確保する必要がある。これまで、受精卵を得るためにはホルモン注射により成熟を促進し、人工授精等により受精卵を確保していた。この手法は煩雑で受精卵の質もあまり良くない。本研究では、光や水温などの環境因子により成熟を促進する技術を開発することを目指して、これまで不明であった血嚢体の生理機能を明らかにすることを目的として実験を行い、脳深部にある血脳体が青色光を受容する光受容器官であり、初期成熟に重要な役割を果たすことを明らかにした。この情報をもとに、環境因子による効率的な種苗生産技術が開発されることが期待される。
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