A histological study of testis development and ultrastructural features of spermatogenesis in cultured Acrossocheilus fasciatus
A histological study of testis development and ultrastructural features of spermatogenesis in cultured Acrossocheilus fasciatus
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DOI：
10.1016/j.tice.2015.10.005
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发表时间：
2016-02-01
期刊：
影响因子：
2.6
通讯作者：
Zhu, Jun-Quan
中科院分区：
文献类型：
--
作者：
Fu, Su-Yan;Jiang, Jian-Hu;Zhu, Jun-Quan
使用光学和电子显微镜研究了商业溪流鱼 Acrossocheilus fasciatus（Cypriniformes，Barbinae）的睾丸发育和精子发生的超微结构特征。 A. fasciatus testes 的繁殖周期分为从 I 阶段到 VI 阶段的六个连续阶段。综合前期研究结果分析，可以确定5月至7月为金带姬蜂的最佳繁殖季节。在此期间，条带蛱蝶的睾丸处于第五阶段，雄性的精子最为丰富。在第一个生殖周期中，性成熟的雄性睾丸在十月返回到第三阶段，随后在此阶段越冬。在A. fasciatus的小叶型睾丸中，发生囊状精子发生，精原细胞受到限制。所有不同阶段的生精细胞均沿生精小叶分布，包括精原细胞、精母细胞、精细胞和精子。在精子发生结束时，生精囊打开，将精子释放到小叶腔中。对致带曲霉精子发生的超微结构观察表明，电子致密物质出现在生殖细胞的不同阶段，从初级精原细胞到次级精母细胞。当这些致密物质游离在细胞质中或邻近核膜时，我们将这些致密物质称为“nuage”，而那些靠近线粒体的物质称为线粒体间水泥。由于存在核旋转，A. fasciatus 中的精子可归类为 I 型。尽管精子头部的核染色质高度浓缩，但没有形成顶体。细胞质管是硬骨精子常见的超微结构特征，也存在于中段。此外，还观察到许多融合的线粒体。构成中心粒复合体的远端中心粒和近端中心粒彼此不完全垂直。鞭毛呈典型的9+2排列模式。相反，我们对A. fasciatus的研究没有提供有关侧鳍的信息，尽管在一些鞭毛末端存在扩大的囊状区域。 (C) 2015 Elsevier Ltd. 保留所有权利。
Testis development and ultrastructural features of spermatogenesis in Acrossocheilus fasciatus (Cypriniformes, Barbinae), a commercial stream fish, were studied using light and electron microscopy. The reproduction cycle in A. fasciatus testes is classified into six successive stages from Stage Ito Stage VI. Based on an analysis of previous results, May to July can be confirmed as the best breeding season for A. fasciatus males. During this time, the A. fasciatus testes are in Stage V and the sperm in males is most abundant. In the first reproductive cycle, sexually mature male testes return to Stage III in October, subsequently overwintering at this stage. In the lobular-type testes of A. fasciatus, cystic type spermatogenesis occurs with restricted spermatogonia. All spermatogenic cells at different stages are distributed along the seminiferous lobules, which contain spermatogonia, spermatocytes, spermatids and spermatozoa. At the end of spermatogenesis, spermatogenic cysts open to release spermatozoa into the lobule lumen. Ultrastructural observation of A. fasciatus spermiogenesis reveals that electron-dense substances appear at the different stages of germ cells, from primary spermatogonia to secondary spermatocytes. We have termed these dense substances as "nuage" when free in the cytoplasm or adjacent to the nuclear envelope, while those close to the mitochondria are called inter-mitochondrial cement. The spermatozoa in A. fasciatus can be classified as type I due to the presence of nuclear rotation. Although the nuclear chromatin in the head of sperm was highly condensed, no acrosome was formed. The cytoplasmic canal, a common ultrastructural feature of Teleostei spermatozoa, was also present in the midpiece. In addition, numerous fused mitochondria were observed. The distal centriole and proximal centriole constituting the centriolar complex were oriented incompletely perpendicular to each other. The flagellum showed a typical 9 + 2 arrangement pattern. Conversely, our study on A. fasciatus yielded no information concerning the lateral fins although an enlarged saclike area was present at the end of some flagella. (C) 2015 Elsevier Ltd. All rights reserved.