THE FINE STRUCTURE OF PRONUCLEAR DEVELOPMENT AND FUSION IN THE SEA URCHIN, ARBACIA PUNCTULATA
THE FINE STRUCTURE OF PRONUCLEAR DEVELOPMENT AND FUSION IN THE SEA URCHIN, ARBACIA PUNCTULATA
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海胆（Arbacia Punctulata）原核发育和融合的精细结构
作者：
F. Longo;E. Anderson
受精事件后的配子质膜合并，并最终在合子核的形成进行了研究，通过光学显微镜和电子显微镜在海胆，Arbacia punctulata。精子通过受精锥后不久，它旋转约180°，并在其入口点的侧面停下来。同时，精子核的无孔核膜发生变性，随后精子染色质分散，原核核膜发育。在精核重组的过程中，形成精子星。后者由卵浆板层结构和微管束组成。雄原核、精子囊和鞭毛伴随精子囊迁移。当原核彼此相遇时，雌性原核的表面靠近前进的雄性原核变得高度卷曲。随后，合子核的形成开始于原核被膜的外膜和内膜的融合，从而产生一个小的核间桥和一个连续的、穿孔的合子核膜。
Fertilization events following coalescence of the gamete plasma membranes and culminating in the formation of the zygote nucleus were investigated by light and electron microscopy in the sea urchin, Arbacia punctulata. Shortly after the spermatozoon passes through the fertilization cone, it rotates approximately 180° and comes to rest lateral to its point of entrance. Concomitantly, the nonperforated nuclear envelope of the sperm nucleus undergoes degeneration followed by dispersal of the sperm chromatin and development of the pronuclear envelope. During this reorganization of the sperm nucleus, the sperm aster is formed. The latter is composed of ooplasmic lamellar structures and fasciles of microtubules. The male pronucleus, sperm mitochondrion, and flagellum accompany the sperm aster during its migration. As the pronuclei encounter one another, the surface of the female pronucleus proximal to the advancing male pronucleus becomes highly convoluted. Subsequently, the formation of the zygote nucleus commences with the fusion of the outer and the inner membranes of the pronuclear envelopes, thereby producing a small internuclear bridge and one continuous, perforated zygote nuclear envelope.