| Project/Area Number |
03454023
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
YONEDA Mitsuki Kyoto Univ. Fac Sci. professor, 理学部, 教授 (50017183)
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| Co-Investigator(Kenkyū-buntansha) |
MARUYAMA Yoshihiko Kyoto Univ. Fac Sci. instructor, 理学部, 助手 (60135514)
KUBOTA Hiroshi Kyoto Univ. Fac Sci. instructor, 理学部, 助手 (40115837)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 1992: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1991: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | DNA synthesis / Starfish / S-pahse / Cell fusion / Cell cycle / Image analysis / BrdU / Meiosis / 核分裂 / 卵母細胞 / ブロモウラシル / 融合核 |
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| Research Abstract |
1. DNA-synthetic period in starfish eggs: Maturing oocytes were fertilized and pulse-labeled with BrdU for detecting S phase in starfish eggs. Fertilized either during or after maturation, eggs entered S-phase before syngamy. In eggs fertilized after maturation, a small area in the zygote nucleus derived probably from the male pronucleus lasted longer to synthesize DNA than the main area. Pattern of BrdU label during S phase was traced and compared with the distribution pattern of chromatin. Image analysis on a computer revealed that the two patterns usually coincide, indicating that DNA synthetic regions in starfish eggs are stretched on a whole length of chromatin.
2. Termination of meiotic division in fused oocytes of starfish: Immature oocytes of Asterina pectinifera were fused by treating them with polyethylene glycol following the procedure of Vassetzky et. al. (1986). 1-nethyladenine caused the fused pair to extrude pair of polar bodies (PB1's and PB2's) on schedule of unfused controls, and the pair eventually formed two pronuclei. Two populations of oocytes with different maturation phases were then fused at random. Those pairs that extruded PB2 from one meiotic nucleus within * 8 min of the PB1 extrusion from the other nucleus were observed. In these heterogenous pairs, the PB2 was not formed from the latter nucleus, and both nuclei went through to form pronuclei. Presence of a cytoplasmic factor to stop cell division in maturing oocytes is suggested.
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