title: Ultrastructure of spermiogenesis and the spermatozoon of Macracanthorhynchus hirudinaceus (Pallas, 1781) (Acanthocephala: Archiacanthocephala), a parasite of the wild boar Sus scrofa.
abstract: The present paper describes the ultrastructure of spermiogenesis and the spermatozoon of Macracanthorhynchus hirudinaceus, an acanthocephalan parasite of the wild boar Sus scrofa. At the beginning of spermatogenesis, spermatocytes exhibit synaptonemal complexes and 2 centrioles. In the spermatid, only 1 centriole remains, generating a flagellum with a 9+2 pattern. Another ultrastructural feature observed during the spermiogenesis of M. hirudinaceus is the condensation of the chromatin, forming a "honeycomb" structure in the old spermatid and a homogeneous, electron-dense structure in the spermatozoon. The mature spermatozoon of M. hirudinaceus presents a reversed anatomy, as has been described previously in other species of the Acanthocephala. The spermatozoon is divided into 2 parts: an axoneme, and a nucleocytoplasmic derivative. The spermatozoon flagellum exhibits a 9+2 or 9+0 pattern. The process of spermiogenesis and the ultrastructural organization of the spermatozoon of M. hirudinaceus are compared with available data regarding other acanthocephalan species.
authors.affiliation: Laboratory of Parasites and Mediterranean Ecosystems, Faculty of Sciences and Technics, University of Corsica, F-20250 Corte, France. foata@univ-corse.fr
authors.forename: Joséphine
authors.initials: J
authors.lastname: Foata
authors.forename: Julia-Laurence
authors.initials: JL
authors.lastname: Culioli
authors.forename: Bernard
authors.initials: B
authors.lastname: Marchand
mesh_terms: D000049:Acanthocephala / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D000835:Animals, Wild; D002502:Centrioles / Q000648:ultrastructure; D002843:Chromatin / Q000648:ultrastructure; D005407:Flagella / Q000648:ultrastructure; D006374:Helminthiasis, Animal / Q000469:parasitology*; D008297:Male; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D013087:Spermatids / Q000648:ultrastructure; D013090:Spermatocytes / Q000648:ultrastructure; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*; D034421:Sus scrofa / Q000469:parasitology*; D013553:Swine Diseases / Q000469:parasitology*; D013573:Synaptonemal Complex / Q000648:ultrastructure
chemical_list: D002843:Chromatin