| Project/Area Number |
03640604
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Okayama University |
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Principal Investigator |
YAMAMOTO Masamichi Fac.Sci., Okayama Univ.Prof., 理学部, 教授 (50011565)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAI Hiroko Fac.Sci., Okayama Univ.Assoc.Prof., 理学部, 助教授 (50090478)
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| Project Period (FY) |
1991 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | cephalopod / ascidian / starfish / germ cell / gonad / meiosis / ovary / testis / 減数分裂 / 始原生殖細胞 / ヤムシ / ユ-レイボヤ / 生殖巣 / 微細構造 / 幼生 / 変態 |
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| Research Abstract |
1. The origin of the germ cell and the early processes of the gonad formation were clarified in a octopus, Octopus ocellatus. The earlygerm cells apear in the pericardial cavity. In the female, the germ cells begin meiosis just before hatching while in the females the germ cells enter into meiosis 7 weeks after hatching.
2. The origin of the germ cell and the process of sex differentiation of the gonads were elucidated in a solitary ascidian, Ciona intestinalis. The germ cells first appear in the juvenile just after metamorphosis in contact with the degenerating tissue mass which arises near the esophagus. The form a spherical body (early gonad), which divides into the testis and the ovary during migration along the wall of the stomach to the pyloric portion.
3. The origin of the germ cell and the process of gonad formation became clear in a star fish, Asterina pectinifera. The germ cells, about 10 in number, originate in the third coelomic pouch of the brachyolaria larvae. The enter into the haemal system and form the gonads after metamorphosis.
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