Sousa M, Corral L, Azevedo C
Department of Cell Biology, University of Oporto, Porto, Portugal.
Gamete Res. 1989 Dec;24(4):393-401. doi: 10.1002/mrd.1120240406.
The ultrastructure of the mature spermatozoa and spermatogenesis of the bivalve Scrobicularia plana are described. Support cells extend from the basal lamina to the lumen of the testis and are laterally connected to the germinal epithelium. Germ cells present intercellular bridges and flagella since the spermatogonial stage. While spermatogonia and spermatocytes appear connected to support cells by desmosome-like junctions, elongated spermatids are held at the acrosomal region by support cell finger-like processes. During spermiogenesis, the acrosomal vesicle differentiates from a golgian saccule and then migrates to the nuclear apex. A microtubular manchette arising from centrioles surrounds the acrosomal vesicle, the nucleus, and the mitochondria at the time these three organelles start their elongation, disappearing after that. The mature spermatozoon of S. plana lacks a distinct midpiece because the mitochondria extend from the region of the pericentriolar complex along the nucleus anteriorly for approximately 1.4 microns. The features of this bivalve type of modified spermatozoon are compared with those of other animal groups having similar modifications.
描述了双壳贝类扁平蚬成熟精子的超微结构和精子发生过程。支持细胞从基膜延伸至睾丸管腔，并在侧面与生殖上皮相连。生殖细胞从精原细胞阶段起就存在细胞间桥和鞭毛。精原细胞和精母细胞通过类似桥粒的连接与支持细胞相连，而细长的精子细胞则在顶体区域被支持细胞的指状突起固定。在精子形成过程中，顶体小泡从高尔基体囊泡分化而来，然后迁移至核尖。当这三个细胞器开始伸长时，由中心粒产生的微管袖套围绕着顶体小泡、细胞核和线粒体，之后消失。扁平蚬的成熟精子缺乏明显的中段，因为线粒体从中心粒复合体区域沿着细胞核向前延伸约1.4微米。将这种双壳贝类改良型精子的特征与其他具有类似改良的动物类群的特征进行了比较。
