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1996 Fiscal Year Final Research Report Summary

The study of regulation in behavior of newt sperm

Research Project

Project/Area Number 07680802
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Developmental biology
Research InstitutionYamaguchi University

Principal Investigator

IWAO Yasuhiro  Yamaguchi University, Faculty of Science, Professor, 理学部, 教授 (10144916)

Project Period (FY) 1995 – 1996
KeywordsFertilization / Newt / Sperm aster / Microtubule / Polyspermy / Xenopus / Sperm nucleus / Ca ion
Research Abstract

The unfertilized egg of the newt, Cynops pyrrhogaster, has a second meiotic spindle at the animal pole and numerous cortical cytasters. After physiologically polyspermic fertilization, all sperm nuclei incorporated into the egg develop sperm asters, and the cortical cytasters change into bundles of cortical microtubules. The size of the sperm asters in the animal hemisphere is about 5.6-fold larger than that in the vegetal hemisphere. Only one sperm nucleus moves towards the center of the animal hemisphere to form a zygote nucleus with the egg nucleus. This movement is inhibited by nocodazole, but not by cytochalasin B.The centrosome in the zygote nucleus divides into two parts to form a bipolar spindle for the first cleavage synchronously with the nuclear cycle, but centrosomes of accessory sperm nuclei in the vegetal hemisphere remained to form monopolar interphase asters and subsequently degenerate around the first clevage stage. The size of sperm asters in monospermically fertilized Xenopus eggs was about 37-fold larger than those in Cynops eggs. Since sperm asters that formed in polyspermically fertilized Xenopus eggs exclude each other, the formation of a zygote nucleus is inhibited. Cynops sperm nuclei form larger asters in Xenopous eggs, whereas Xenopus sperm nuclei form smaller asters in Cynops eggs compared with those in homologous eggs. Since there was no significant difference in the concentration of monomeric tubulin between those eggs, the size of sperm asters is probably regulated by a component (s) in egg cytoplasm. Smaller asters in physiologically polyspermic newt eggs might be useful for selecting only one sperm nucleus to move towards the egg nucleus.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Yasuhiro Iwao: "Activation of Xenopus eggs by Cynops sperm extract is dependent upon both extra-and intra-cellular Ca Activities" Zoological Science. 12. 573-581 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Iwao: "Activation of newt eggs in the absence of Ca^<2+> activity by treatment with cycloheximide and D O" Develop.,Growth & Differ.37. 641-651 (1995)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Iwao: "Activation of Xenopus eggs by RGD-containing peptides accompanied by intracellular Ca^<2+> release" Developmental Biology. 177. 558-567 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuhiro Iwao: "Changes in microtubule structures during the first cell cycle of physiologically polyspermic newt eggs" Molecular Reproduction & Development. (in press).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yashiro Iwao: "Activation of Xenopus eggs by Cynops sperm extract is dependent upon both extra- and intra-cellular Ca activities." Zoological Science. 12. 573-581 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yasuhiro Iwao: "Activation of newt eggs in the absence of Ca^<2+> activity by treatment with cycloheximide or D_2O Development" Growth & Differentiation. 37. 641-651 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yasuhiro Iwao: "Activation of Xenopus eggs by RGD-containing peptides accompanied by intracellular Ca^<2+> release" Developmental Biology. 177. 558-567 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yasuhiro Iwao: "Changes in microtubule structures during the first cell cycle of physiologically polyspermic newt eggs." Molecular Reproduction & Development. (in press).

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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