Fine Structure of the Mastigont System in Trichomonas tenax (Zoomastigophorea: Trichomonadida)

Abstract

Fine structure of mastigont system in Trichomonas gallinae conforms to that described previously from other species of Trichomonadinae. This pertains to arrangement of kinetosomes 1-4 as well as to rootlet filaments associated with kinetosomes [i.e., kinetosomal filaments 1 to 3, parabasal filaments 1 and 2, latter of which subtends parabasal body (Golgi complex)] and costa. The axostyle and pelta, which overlaps left ventral surface of anterior segment of axostylar capitulum along peltar-axostylar junction and is subtended by sigmoid F2 filaments, consists of microtubules about 20 nm in diameter. The terminal segment of tubular trunk of axostyle projects beyond posterior surface of cell. The parabasal filaments and costa have similar periodicity of about 42 nm, but differ in their ultrastructure (parabasal filament, Type A; costa, Type B). Hydrogenosomes are distributed throughout cytoplasm, many of them, the paracostal granules, aligned along costa. The undulating membrane is a fin-like fold extending from dorsal cell surface; it encloses periodic marginal lamella. The recurrent flagellum is apposed to membrane close to its external margin. The part of fold distal to area of contact with recurrent flagellum encloses terminal loop of marginal lamella; it corresponds to accessory fila-