The ultrastructure of the epimastigote stages of Trypanosoma rotatorium in the leech Batracobdella picta

Abstract

Large numbers of epimastigotes were observed adjacent to the gastric epithelium of leeches (Batracobdella picta) that had fed 18 days earlier on a frog infected with Trypanosoma rotatorium. Electron microscopic study revealed that the modified flagellar sheaths of some of the epimastigotes formed hemidesmosomes with the gastric epithelium. Cytoplasmic components of the parasites included free ribosomes, sparse agranular reticulum, a well developed mitochondrial tube with plate-like cristae in the pre- and post-nuclear regions, two types of lipid inclusions, and two types of vesicular inclusions. The basal region of the typical flagellar apparatus was surrounded by an electron-dense, cylindrical sleeve situated immediately beneath the plasmalemma of the flagellar pocket. A polysaccharide component was demonstrated cytochemically on the outer surface of the plasma membrane of the epimastigotes.