Hydrogenosome morphological variation induced by fibronectin and other drugs in Trichomonas vaginalis and Tritrichomonas foetus.

The hydrogenosome is a spherical organelle, found in some anaerobic protozoa, which participates in ATP and molecular hydrogen formation. The morphological alterations in hydrogenosomes induced by fibronectin, hydroxyurea and cytochalasin B in Trichomonas vaginalis and Tritrichomonas foetus are presented. We demonstrate that, under experimental conditions, the hydrogenosome presents a high diversity in size and shape, suggesting a mechanism that seems to compensate for the stress provoked by drugs. The following experimental procedures were used: (1) fibronectin-mediated endocytic activity, (2) 4 mM hydroxyurea for 15 h, and (3) 10 microg cytochalasin B/ml in the culture medium. The main alterations observed in hydrogenosomes were: (1) formation of giant hydrogenosomes, (2) presence of internal membranes, (3) increased diversity of non-spherical forms, some of them bizarre, (4) presence of sub-compartments in the matrix, as vesicles, (5) presence of ribosome-like particles on the outer hydrogenosomal membrane, (6) enlargement of the peripheral vesicle, and (7) continuity with membrane profiles.