| Project/Area Number |
61540515
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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 | Ochanomizu University. |
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Principal Investigator |
NEMOTO Shin-ichi Tateyama Marine Lab., Fac. of Sci., Ochanomizu Univ. (Associate professor), 理学部・臨海実験所, 助教授 (60017209)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Kenya Dept. of Biol., Fac. of General Edu., Gifu Univ.,(Instructor), 教養部・生物, 助手 (50182621)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | oocyte maturation / meiosis / germinal vesicle / cell cycle / starfish / 減数分裂 |
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| Research Abstract |
The aim of this study is to know the character of factor(s) in the germinal vesicle which is required for male pronucleus formation and cyclic changes in cytoplasm in starfish oocytes. For this purpuse, we developeda simple technique for mass isolation of germinal vesicles (GVs) from starfish oocytes.
Immature oocytes, free of follicular envelop and the vitelline coat, were treated with cytochalasin B to decrease the rigidity of the oocyte cortex. The oocytes were centrifuged on a discontinuous sucrose-density gradient. GVs and enucleated oocytes came to rest in separate layers according to their density. The isolated GVs were unfform in size and morphology, and appeared morphologically very similar to intact ones in the oocytes. The GVs were smashed by freezing and thawing in an extraction buffer. The activity of the factor was present in a supernatant obtained by centrifuging the homogenate at 10,000xg. After further centrifuging the supernatant at 100,000xg for 1 hr. the factor was observed in a middle fluffy layer between supernatant and precipitate. By treating with either heat or papain the activity was vanished. These results suggest that the factor is a protein either having relatively high molecular weight or binding some large molecular structure(s). No species specificity was observed among 4 species of starfishes and one species of cucumber, indicating the presence of a common factor among echinoderm. The activity of the factors was detected even in the germinal vesicle of a small oocytes which had no competence to the maturation-inducing hormone and was only a half of fully grown oocytes in volume.
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