INVITRO FERTILIZATION IN CTENOPHORES - SPERM ENTRY, MITOSIS, AND THE ESTABLISHMENT OF BILATERAL SYMMETRY IN BEROE-OVATA
INVITRO FERTILIZATION IN CTENOPHORES - SPERM ENTRY, MITOSIS, AND THE ESTABLISHMENT OF BILATERAL SYMMETRY IN BEROE-OVATA
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DOI：
10.1016/0012-1606(91)90296-f
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发表时间：
1991-10-01
影响因子：
2.7
通讯作者：
SARDET, C
中科院分区：
文献类型：
--
作者：
CARRE, D;ROUVIERE, C;SARDET, C
我们首次发现了在鞭毛虫(Beroe Ovata)中控制体外受精的方法。这是基于在配子释放时存在对自花受精的部分阻碍，这可以通过去除卵膜来克服。它使我们能够利用Beroe卵子的优良光学特性来对所有事件进行详细观察，从精子在这些生理多精卵中的穿透或穿透到第一次卵裂，并扩展我们最初的观察(Carré和Sardet，1984)。精子进入的特征是在一个或多个穿透部位周围70-μm区域内卵子皮质的局部修饰。精子进入后，卵子表面局部收缩和松弛，然后形成受精锥并消失。伴随这些事件的是局部胞吐、微绒毛环状生长、卵皮质增厚和精子原核周围线粒体聚集。然后，雌性原核在卵子表面下向一个或连续的精子原核迁移。原核融合、精子和卵染色质混合，以及有丝分裂也异常清晰。此外，我们还注意到，雌性原核最后一个轨迹的方向往往决定了有丝分裂纺锤体的方向，从而决定了第一个单极分裂沟的位置。这进而决定了胚胎和成体B的未来矢状面。卵形。
We have found ways to controlin vitrofertilization in a ctenophore (Beroe ovata) for the first time. This is based on the existence of a partial block to self-fertilization at the time of gamete release which can be overcome by removal of the egg envelope. It has allowed us to exploit the excellent optical properties of Beroe eggs to make detailed observations on all events from sperm penetration or penetrations in these physiologically polyspermic eggs to first cleavage, and to extend our initial observations (Carré and Sardet, 1984). Sperm entry is characterized by local modifications of the egg cortex in a 70-μm zone around the penetration site or sites. Upon sperm entry, the egg surface contracts and relaxes locally, then a fertilization cone forms and disappears. These events are accompanied by localized exocytosis, growth of a ring of microvilli, thickening of the egg cortex, and gathering of mitochondria around the sperm pronuclei. The female pronucleus then migrates beneath the egg surface toward one or successive sperm pronuclei. The fusion of pronuclei, sperm and egg chromatin intermixing, and mitosis were also observed with exceptional clarity. Furthermore, we have noticed that the direction of the last trajectory of the female pronucleus tends to define the orientation of the mitotic spindle, and as a consequence the position of first unipolar cleavage furrow. This in turn determines the future sagittal plane of the embryo and of the adultB. ovata.