title: Morphological features of spermatozoa of Paragonimus ohirai (Trematoda: Platyhelminthes) examined by a silver nitrate staining technique.
abstract: The mature thread-like spermatozoon of Paragonimus ohirai was shown to be composed of 7 distinct segments which have morphologically different characteristics, following staining with silver nitrate. The first segment (1S) is a needle-shaped structure with a perforatorium. The 2S is composed of two filaments loosely paired; 3S consists of a somewhat coarse thread (vestige of the cytoplasmic projection); 4S is composed of two flagella tightly paired; in 5S, two silver-positive filaments are independently seen as in 2S; 6S has a 'spiral' structure composed of two flagella; in 7S, two filaments are seen dissociated from each other. The sperm nucleus exists within the 'spiral' structure of 6S and this structure may serve to hold and/or protect the nucleus. The technique presented here is useful for gross morphological observations of the long sperm of flatworms.
authors.affiliation: Department of Parasitic Diseases, Kumamoto University Medical School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Hirai
authors.forename: I
authors.initials: I
authors.lastname: Tada
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D008297:Male; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast; D010238:Paragonimus / Q000502:physiology / Q000648:ultrastructure*; D016622:Silver Staining; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*