Mode of action and role of neurohormone in the regulation of reproductive functions and its application for artificial seed production in major bivalves

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H04978
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic life science
• Research Institution: Tohoku University
• Principal Investigator: Osada Makoto 東北大学, 農学研究科, 教授 (30177208)
• Co-Investigator(Kenkyū-buntansha): 長澤 一衛 東北大学, 農学研究科, 助教 (50794236)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 二枚貝 / 性分化 / 性成熟 / 産卵 / 神経内分泌 / GnRH / ステロイドホルモン / 性特異的遺伝子

Outline of Final Research Achievements

Peptide sequences of gonadotropin releasing hormones (GnRHs), which are conserved among bivalves, was characterized in comparison with vertebrates. Induction of sex differentiation based on the observed difference of sex specific gene expression among sexes and germ cell development with two types of scallop GnRHs were demonstrated. And the occurrence of steroidogenic pathway-related genes, which is suggested mediating the abovementioned GnRH function, was proposed and sex specific profile of these genes between sexes during reproductive cycle was suggested.
Primary structure of oocyte maturation arresting factor (OMAF), which is a neural factor to interfere serotonin-induced spawning was revealed. And neutralizing full OMAF antibody resulted in blockage of OMAF-inhibited serotonin function and activation of spawning of male and sperm motility.

Free Research Field

水産増殖学

Academic Significance and Societal Importance of the Research Achievements

近年、害的生物による食害や感染による斃死に加え、環境激変による資源量や養殖生産量の激減によって、環境と共生する漁業として世界に認められている、二枚貝養殖の持続的な生産が危ぶまれている。それを解決するためには、二枚貝の人工種苗生産技術の開発が急務である。
その基盤となる二枚貝における性分化・性成熟・産卵に関する生殖内分泌調節機構の知見を深化させ、人工種苗生産技術として応用する意義は、食料としての水産物増産のみならず、生殖内分泌機構に関わる生物の普遍的なメカニズムとその進化の解明においても非常に大きな意義がある。