Reinvestigation of the ultrastructure of spermiogenesis and the spermatozoon of Hymenolepis nana (Cestoda, Cyclophyllidea), parasite of the small intestine of Rattus rattus

• Published in: Molecular Reproduction and Development
• Main Authors: Bâ, Cheikh Tidiane, Marchand, Bernard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Doublets; Doublets The; Rattus rattus
• Online Access: http://dx.doi.org/10.1002/mrd.1080330106; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fmrd.1080330106; https://onlinelibrary.wiley.com/doi/pdf/10.1002/mrd.1080330106

Abstract Spermiogenesis in Hymenolepsis nana begins with the formation of a differentiation zone. This is limited at the front by arched membranes, is surrounded by cortical microtubules assoicated with 12 crested‐like bodies, and contains a single centriole made up of doublets. The distal centriole gives rise to a flagellum that grows at the same pace as the cortical microtubules. Migration of the nucleus takes place after the formation of the flagellum. It is followed by the separation of the old spermatid from the residual cytoplasm. The mature H. nana spermatozoon is filiform and lacks mitochondria. The axoneme, of the 9 + “1” pattern of the Platyhelminthes, does not reach the extremities of the spermatozoon. The nucleus is electron dense and is in close contact with the axoneme around which it coils in a spiral making an angle of 10° to 15° with the spermatozoon axis. The cortical microtubules follow a 10° to 15° helicoidal path along almost their whole length, except at their posterior extremity, where they are parallel to the spermatozoon axis. H. nana is distinguished by the early development of 12 crested‐like bodies of different lengths and by the existence of a single centriole in the differentiation zone. Such a high number of crested‐like bodies had never previously been reported in a cestode. © 1992 Wiley‐Liss, Inc.