黄颡鱼(Pseudobagrus fulvidraco)精子的超微结构

THE ULTRASTRUCTURE OF SPERMATOZOON OF THE TELEOST PSEUDOBAGRUS FULVIDRACO

黄颡鱼精子由头部、中段和鞭毛(尾部)三部分组成。头部的主要结构是细胞核。核中浓缩了的染色质呈颗粒状。染色质中有核泡存在。核泡中有致密颗粒状物。植入窝里井状,从核后端往前深陷入核的中央。中段的中心粒复合体位于植入窝中,结构独特。近端中心粒和基体首尾相对,排在同一直线上。某些精子的近端中心粒的中央腔中能见到一、二个粗大的颗粒状物。基体的中央腔中有一对中央微管。近端中心粒和基体之间有中心粒间体将两者隔开。中段的袖套连接于细胞核之后,其中分布着线粒体和一些囊泡。近袖套内膜处的细胞质中有一层膜与袖套内膜平行。鞭毛细长,其起始端位于袖套腔中。鞭毛上长有两排侧鳍。侧鳍呈波纹状,分居轴丝两侧,大致与轴丝的两条中央微管同在一个平面上。侧鳍的基部有囊泡。

The spermatozoon of the teleost, Pseu-dobagrus fulvidraco (Richardson) consists of three parts: head, midpiece and flagel-lum (tail). The main structure of the head is nucleus. At the posterior end of the nucleus, the implantation fossa, which is like a well, sinks deep into the center of the nucleus. Within grain-like condensed chromatin there are some less dense areas, i. e. nuclear vacuoles, in which electron-dense particles can be seen. The midpiece is made of centriolar complex and sleeve. The centriolar complex is at the implantation fossa. The structure of the centriolar complex is unique. The proximal cen-triole and the basal body are arranged in a line. Occasionally there may be one or two big electron-dense particles in the central space of the proximal centriole. And within the central space of the basal body, there is a central pair of single mi-crotubules. The intercentriolar body is located between the proximal centriole and the basal body and is perpendicular to them. It has not been reported that there are intercentriolar bodies in the mature spermatozoa of other teleosts. The sleeve of the midpiece is connected to the posterior end of the nucleus. There are mitochondria and some vesicles in the sleeve. Near the inner membrane of the sleeve, there is a membrane which is thinner than the plasma membrane and is parallel to the inner membrane of the sleeve. The flagellum of the spermatozoon is thin and long. The proximal end of it is located in the central space of the sleeve. There are two rows of lateral fins on the flagellum, each on one side of the axoneme. The lateral fins are rippled. They are roughly in the plane of the central pair of single microtubules of the axoneme. At the root of the lateral fin there are some vesicles.