FINE-STRUCTURE OF SHEEP FERTILIZATION INVITRO
FINE-STRUCTURE OF SHEEP FERTILIZATION INVITRO
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DOI：
10.1002/mrd.1120190308
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发表时间：
1988-03-01
期刊：
影响因子：
--
通讯作者：
CROZET, N
中科院分区：
文献类型：
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作者：
CROZET, N
用电子显微镜观察了绵羊卵母细胞的受精过程。对32个从超排母羊输卵管中回收的卵母细胞进行体外受精，并在受精的不同阶段进行了分析。精子在受精后2小时即进入卵浆。一小时后，解聚的精子染色质上方发育出一个含有极少细胞器的受精锥。这是一种暂时性结构，在雄性原核形成时消失了。卵母细胞的第二次减数分裂在精子掺入后不久恢复，第3~4h出现第二极体收缩，极体收缩与微丝伴生。雄核和雌核均在等电点5h形成，并被含有孔洞复合体的核膜包裹。雌性精巢以染色质凝集为特征，雄性精巢与精子颈和近中段紧密相连。此后，Pn向卵子的中心迁移，在那里观察到21h的第一次卵裂分裂的纺锤体。在等电点2~4h分析的受精卵含有2个解聚精子头和2个受精锥体，它们已达到同一阶段，这表明可能有少数精子同时穿透。多原核卵以Pn迁移障碍为特征。
The fertilization events of the sheep oocyte have been investigated by electron microscopy. Thirty-two oocytes recovered from the oviducts of superovulated ewes were fertilized in vitro by a procedure that has given rise to full embryonic development (Crozet et al.: Gamete Res. 16:159-170, 1987) and were analyzed at different stages of fertilization. Sperm incorporation in the ooplasm occurred as early as 2 h postinsemination (PI). One hour later, a fertilization cone containing very few cytoplasmic organelles developed above the decondensing sperm chromatin. It was a transitory structure which disappeared when the male pronucleus (PN) was formed. The second meiotic division of the oocyte resumed soon after sperm incorporation; abstriction of the second polar body occurred by 3-4 h PI; the polar body constriction was associated with microfilaments. Both the male and female PN were formed at 5 h PI and were surrounded by nuclear envelopes containing pore complexes. The female PN was characterized by patches of condensed chromatin; the male PN was closely associated with the sperm neck and proximal midpiece. Thereafter the PN migrated toward the center of the egg, where the spindle of the first cleavage division was observed at 21 h PI. Dispermic ova analyzed at 2-4 h PI contained 2 decondensing sperm heads and 2 fertilization cones which have reached the same stage, thus suggesting that a few sperm may penetrate quite simultaneously. Multipronucleate eggs were characterized by disturbance of the PN migration.