| Project/Area Number |
12045243
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Osaka University |
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Principal Investigator |
MURATA Michio Osaka University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (40183652)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Manabu University of Tokyo, Misaki Marine Biological Station, Lecturer, 大学院・理学系研究科, 講師 (60301785)
松森 信明 大阪大学, 大学院・理学研究科, 助手 (50314357)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥16,800,000 (Direct Cost: ¥16,800,000)
Fiscal Year 2002: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2001: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2000: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | Nanomolar structure determination / Sperm attractant / Sperm activating substance / Tunicates / Sterol sulfate / NMR structure determination / Tandem mass spectrometry / Total synthesis / アンフォテリシンB / ポリエン抗生物質 / 作用機構 / クロスリンカー / コレステロール / エルゴステロール / 鍵化学物質 / 誘引物質 / タンパク質糖化 / 高感度NMR |
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| Research Abstract |
Chemotaxis of sperm toward eggs during fertilization is a crucial event for species conservation, particularly for animals living in aquatic environments. Relevant chemical attractants have been found from a few marine organisms such as sea urchins and corals. We previously showed that sperm of the ascidian Ciona intestinalis is activated and then attracted toward the egg by a factor released from the egg, which led to the purification of sperm-activating and attracting factor (SAAF) from the egg-conditioning medium of Ciona intestinalis.
The structure of SAAF was proposed to be a novel polyhydroxysterol sulfate on the basis of 2D-^1H NMR and FAB-MS/MS analysis using no more than approximately 4 microgram of a specimen. However, there still remained small but serious ambiguity that the biological activity might be attributed to a minor constituent. Synthesis is, therefore, essential for the unequivocal identification of SAAF as the active principle, and for the complete structure elucidation including the stereochemistry at C25. SAAF and its C-25 epimer were synthesized from chenodeoxycholic acid in 19 steps via the pivotal intermediate and both the sperm-activating and attracting activity of them were bioassayed. Synthetic SAAF activated the sperms of ascidian Ciona intestinalis at 3.7 nM and concurrently exhibited the attracting activity at<10 nM, which led to the unambiguous structure determination of SAAF and the verification of its dual activity. It is noteworthy that 25-epi-SAAF turned out to possess the comparative activities as those of SAAF.
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