Ashour A A, Garo K, Gamil I S
Faculty of Science, Ain Shams University, Abbassia, 11566 Cairo, Egypt.
J Helminthol. 2007 Sep;81(3):219-26. doi: 10.1017/S0022149X07409816. Epub 2007 Jun 21.
The process of spermiogenesis in two paramphistomes, Sandonia sudanensis and Basidiodiscus ectorchis from the Nile fish Synodontis schall in Egypt was studied by transmission electron microscopy. Spermiogenesis is characterized by the outgrowth of the zone of differentiation, presenting two basal bodies separated by a microtubule organizing centre, each basal body developing into a flagellum. Proximodistal fusion of these flagella with a median cytoplasmic extension gives rise to the spermatozoon. The mature spermatozoon possesses two axonemes of the 9+'1' pattern typical of parasitic helminths. There are few ultrastructural studies on spermiogenesis in paramphistomes, which are considered the most primitive digenetic trematodes. The present study provides new and more detailed information on this process, including the presence of a lateral flange and external ornamentation of the cell membrane. The value of sperm ultrastructure as a taxonomic tool in phylogeny is also discussed.
利用透射电子显微镜对来自埃及尼罗河鱼类沙氏歧须鮠的两种同盘吸虫——苏丹桑多吸虫和外睾基盘吸虫的精子发生过程进行了研究。精子发生的特征是分化区的长出，呈现出由一个微管组织中心分隔的两个基体，每个基体发育成一条鞭毛。这些鞭毛与中间的细胞质延伸部进行近远端融合，从而产生精子。成熟精子具有两条呈寄生蠕虫典型的9 +'1'模式的轴丝。关于同盘吸虫精子发生的超微结构研究很少，同盘吸虫被认为是最原始的复殖吸虫。本研究提供了关于这一过程的新的更详细信息，包括侧缘的存在和细胞膜的外部装饰。还讨论了精子超微结构作为系统发育分类工具的价值。
