彩虹明樱蛤精子发生的超微结构

应用透射电镜观察彩虹明樱蛤的精子发生过程,描述了从精原细胞发育成为成熟精子过程中的超微结构变化。主要表现在染色质以颗粒状形式浓缩和分散;高尔基体分泌的前顶体颗粒逐渐融合形成前顶体囊、前顶体最终发育成为顶体;线粒体逐渐融合形成精子中段;细胞核的拉伸和旋转以及中心体和鞭毛的形成等。在初级精母细胞阶段,同源染色体经历了联会复合体形成和解体的变化。前顶体颗粒和中心粒结构在精原细胞期就已经存在。根据染色质和顶体发育的变化特点将精细胞分为6个时期,并描述了各期精细胞的超微结构特点。彩虹明樱蛤成熟精子属于原生型,由头部、中段和尾部组成。

Ultrastructure of the spermatogenesis of Moerella iridescens Benson

The ultrastructure of spermatogenesis of Moerella iridescens Benson was observed by using transmission electron microscopy.There were five developmental stages in the spermatogenesis including spermatogonium、primary spermatocyte、secondary spermatocyte、spermatid and sperm.The ultrastructural changes from spermatogonium to sperm were described.These changes mainly including the granular condensation and dispersion of chromatin;the formation of proacrosomal vesicles by fusion of proacrosomal granules from Golgi bodies and final formation of acrosome;the fusion and development of mitochondria and finally became the mid-piece of sperm;the extending and rotating of the nucleus and transfer of centrioles and the formation of flagella.At the stage of primary spermatocyte,paired homologous chromosomes started to form synaptonemal complexes.The synaptonemal complexes were fully foemed at pachytene and dissolved afterward.The proacrosomal granules and centriole were existed at the stage of spermatogonium.The differentiation of the spermatid could be divided into six stages according to the change of chromatins,the shape of nucleus and the development of acrosome,and the characteristics of ultrastructure of spermatid at different stages was described.The mature sperm of Moerella iridescens Benson was a typical primitive type consisting of three segments: head,middle piece and tail.