Cytochemical Localization of Hydrogenase Activity in the Anaerobic Protozoa Trichomonas vaginalis, Plagiopyla nasuta and Trimyema compressum

SUMMARY: A cytochemical staining method was developed for the demonstration of hydrogenase activity in hydrogenosomes of Trichomonas vaginalis. After fixation in low concentrations of glutaralde-hyde under strictly anaerobic conditions and incubation of these cells in the presence of H2 and the tetrazolium compound 2-(2′-benzothiazolyl)-5-styryl-3-(4′-phthalhydrazidyl)-tetrazolium chloride, an electron-dense deposit was produced in the hydrogenosomes. The method was used to demonstrate the hydrogenosomal nature of similar microbodies of the sapropelic ciliates Plagiopyla nasuta and Trimyema compressum.