Electron microscopic study of the effect of zinc on Tritrichomonas foetus.

At concentrations of 3.1 to 24 mM, zinc inhibits the multiplication of and kills the pathogenic protozoan Tritrichomonas foetus. Transmission electron microscopy showed that the hydrogenosome, a organelle which is involved in the metabolism of pyruvate and the site of formation of molecular hydrogen, constitutes the main site of the initial effect of zinc. The hydrogenosomal vesicle increases its electron density and dimension. Electron spectroscopy imaging and the electron energy loss spectrum showed the presence of zinc, calcium, and oxygen in the electron-dense areas of the hydrogenosome.