Casas M T, Subirana J A
Department of d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Barcelona, Spain.
Mol Reprod Dev. 1994 Feb;37(2):223-8. doi: 10.1002/mrd.1080370214.
We describe chromatin condensation and acrosome development during spermiogenesis of Ensis ensis. The overall shape of the mature spermatozoon corresponds to the primitive type. The nucleus is oval and on its superior pole there is an elongated acrosome; the middle piece contains four mitochondria around the centriolar complex. The condensation of the nuclei seems to occur in three steps: first the diameter of chromatin fibers increases slightly from 17 to 20 nm; second, in midspermatids fiber pairs coalesce; and third, the coalescence continues by addition of other fibers until the nuclei become highly compacted. Chromatin changes are related with nuclear protein composition. Small proacrosomal vesicles show two regions of different electron density. At a later stage they fuse to give a single, spherical vesicle in round spermatids, which migrates to the upper pole and transforms into a tapered acrosome (18 microns long) with a central channel filled with finely fibrous material.
我们描述了中国毛蚶精子发生过程中的染色质凝聚和顶体发育。成熟精子的整体形状对应于原始类型。细胞核呈椭圆形，在其上端有一个细长的顶体；中段在中心粒复合体周围含有四个线粒体。细胞核的凝聚似乎分三步进行：首先，染色质纤维的直径从17纳米略微增加到20纳米；其次，在精子细胞中期纤维对合并；第三，通过添加其他纤维继续合并，直到细胞核高度致密。染色质变化与核蛋白组成有关。小顶体前泡显示出两个不同电子密度的区域。在后期，它们融合形成一个单一的球形泡，存在于圆形精子细胞中，该泡迁移到上端并转化为一个锥形顶体（长18微米），其中心通道充满精细的纤维状物质。
