Research Activities- OSADA Makoto -

Bivalv mollusc is one of the most important commercial marine animals all over the world. An artificial control of gametogenesis and spawning greatly contributes to achieve an efficient and sustainable production in aquaculture. We are carrying forward the project to know the endocrine regulatory mechanism of gametogenesis and spawning.

It is a freshwater and seawater as environmental water to where an artificial pollutant released to environment (eg, estrogen analogues) eventually reaches. It is supposed that sessile bivalve species, blue mussel (Mytilus edulis) and freshwater mussel (Eliptio complanata) are unique organisms to assess environmental water, because these species would be always exposed and influenced by environmental pollution at a certain area rather than fishes which can move to avoid from polluted water.
Vtg synthesis in fishes and imposex in gastropods have been well studied with regard to endocrine disruption. Two-Hybrid assay using transformed yeast has been applied to assess estrogen analogues in environmental water, although some problems on removal of contaminants to interfere the assay from the estrogen fraction of the environmental water still remained. We will focus on the Vtg synthesis in bivalve mollusk, especially blue mussel, in which steroidogenesis is well known, elucidate the involvement of endogenous and exogenous estrogenic substances in vitellogenesis of mussel, and demonstrate the validity of Vtg synthesis of mussel as a biomarker.
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