title: Ultrastructure of the spermatozoon of Parachristianella trygonis Dollfus, 1946 (Trypanorhyncha: Eutetrarhynchidae).
abstract: The ultrastructural organization of the mature spermatozoon of the trypanorhynch cestode Parachristianella trygonis is described by transmission electron microscopy. The spermatozoon is a long and filiform cell, tapered at both ends, lacking both mitochondrion and crested bodies. Its cytoplasm contains 2 axonemes of the 9+'1' pattern of the Trepaxonemata longitudinally displaced, parallel cortical microtubules, the nucleus and glycogen in form of both alpha-glycogen rosettes and beta-glycogen particles. The anterior extremity of the spermatozoon is characterized by the presence of an arclike row of up to 10 parallel cortical microtubules that partially surround the first axoneme. The present study emphasizes the ultrastructural similarity between mature spermatozoa of all 4 trypanorhynchs that have been studied to date. Nevertheless, several features, i.e., the characteristics of spermatozoa extremities, the absence of crested bodies, and the possible presence of an arclike layer of cortical microtubules, need a more thorough analysis or confirmation in some of these species.
authors.affiliation: Laboratori de Parasitologia, Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Av. Joan XXIII, sn, E-08028 Barcelona, Spain. jordimiquel@ub.edu
authors.forename: Jordi
authors.initials: J
authors.lastname: Miquel
authors.forename: Zdzisław
authors.initials: Z
authors.lastname: Swiderski
authors.forename: Lassad
authors.initials: L
authors.lastname: Neifar
authors.forename: Catarina
authors.initials: C
authors.lastname: Eira
mesh_terms: D000818:Animals; D002589:Cestoda / Q000648:ultrastructure*; D002590:Cestode Infections / Q000469:parasitology / Q000662:veterinary; D005393:Fish Diseases / Q000469:parasitology; D008297:Male; D046529:Microscopy, Electron, Transmission; D012860:Skates, Fish / Q000469:parasitology; D013094:Spermatozoa / Q000648:ultrastructure*