title: Rickettsiae and giant lysosomes in the testes of Temnocephala novaezealandiae (Platyhelminthes: Temnocephaloidea).
abstract: Rickettsiae are concentrated in the testes of Temnocephala novaezealandiae, where they occupy the cytoplasm of spermatogenetic stages and the testis epithelia. They have gram negative ultrastructural characteristics and are surrounded by clear zones which are not membrane-limited; indented mitochondria are associated with the clear zones. Propagation occurs by simple division. Extensions of the testis epithelium envelop cloned groups of spermatocytes, spermatids and spermatozoa. Heterophagosomes isolating unmodified rickettsiae, and giant lysosomes enclosing bacteria in advanced stages of degradation, are contained within the epithelial processes. Rickettsiae and large lysosomes were found also in testes of Troglocaridicola mrazeki, a scutariellid. Peririckettsial lucid zones are interpreted as areas of histopathy where host cytoplasm has been catabolized by bacterial enzymes. The rickettsiae evidently are true parasites, although they have no apparent harmful effect on the general condition of their hosts. Digestion of bacteria in lysosomes may provide nutrients for spermatogenetic stages. Transmission of rickettsiae to juvenile temnocephalids does not occur via the spermatozoa.
authors.affiliation: Department of Zoology, University of Canterbury, Christchurch, New Zealand.
authors.forename: J B
authors.initials: JB
authors.lastname: Williams
mesh_terms: D000818:Animals; D004848:Epithelium / Q000382:microbiology / Q000648:ultrastructure; D008247:Lysosomes / Q000382:microbiology / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D010986:Platyhelminths / Q000382:microbiology* / Q000648:ultrastructure; D012281:Rickettsia / Q000648:ultrastructure*; D013094:Spermatozoa / Q000382:microbiology / Q000648:ultrastructure; D013737:Testis / Q000382:microbiology* / Q000648:ultrastructure