龟足精子发生和成熟精子的超微结构

对龟足(Pollicipes metella）精子发生和成熟精子的超微结构进行了研究．精子发生属于变态型．细胞由多边形变为椭圆形到长梨形直至弹开成线形；胞核由椭圆形逐渐变长弯曲成U形，最后变为细长形；中期精子细胞出现的椭圆形附属小滴也弯曲成U形，最终成长柱状．早期、中期、后期精子细胞出现核周微管及核囊，核周微管及核囊在成熟精子中消失．精子为前中部带有一个长柱状附属小滴的线状结构(长约36μm)，可分为顶体、颈部、中段和尾部四部分．顶体为锥状(约0．6μm)，顶体后的基体发出轴丝，轴丝纵贯末端．核细长线状(约16μm)．附属小滴长柱状(约8μm)，内有棒状致密斑．核、附属小滴与轴丝并行．鞭毛为典型的“9 2”结构。     

日本沼虾三种细胞器在精子发生过程中变化的研究

应用透射电镜技术,研究了日本沼虾在精子发生过程中线粒体、溶酶体及内质网的变化．从精原细胞到精子,生精细胞内线粒体数量逐渐增多,结构渐趋复杂化,并形成衍生物,参与精子顶体的形成．溶酶体从初级溶酶体逐渐形成次级溶酶体,其中包括包裹溶酶体及溶噬体;部分溶酶体构成精子顶体的一部分．精子发生的全过程中,未见典型的粗面内质网（ＲＥＲ）,仅见泡状粗面内质网（ＶＲＥＲ）;滑面内质网只在精原细胞期出现．支持细胞的作用包括两个方面：一为支持作用,使生精细胞有一个适宜的发育场所;二为营养作用,为生精细胞的发育提供足够的物质和能量．     

Comparative effects of trivalent and hexavalent chromium on spermatogenesis of the mouse

It has been repeatedly stressed that the biological effectiveness of chromium depends entirely on its oxidation state. The present work compares the histological effects of ingested trivalent and hexavalent chromium compounds on the mouse testes. The results showed comparable data of food consumption and gain in body weight. Both compounds produced ambiguous levels of degeneration in the outmost cellular layers of a number of seminiferous tubules, reduced the number of spermatogonia per tubule and the sperm count, and caused significant increases in the percentage of morphologically abnormal sperms. Generally, all these effects were more pronounced in animals which ingested the hexavalent chromium.