Further studies on the surface charge of various strains ofTrichomonas vaginalis andTritrichomonas foetus

The surface charge of three strains ofTrichomonas vaginalis and five strains ofTritrichomonas foetus was determined by direct measurement of the mean cellular electrophoretic mobility (EPM) of cells suspended in solutions of different ionic strength and pH. No differences were observed in the mean EPM among the two species, although significant differences among the strains exist. Strains that are more pathogenic to mouse, as measured using the subcutaneous assay, had a surface more negative. Treatment of the parasites with trypsin or neuraminidase reduced significantly their mean EPM and increased their isoelectric point.Tritrichomonas foetus was more sensitive to the enzyme treatment thanT. vaginalis. Enzyme-treated cells recovered their normal EPM if, after enzyme treatment, they were incubated in fresh culture medium. The recovery process of trypsintreated cells was inhibited 10–20% by addition of inhibitors of either protein synthesis (puromycin) orN-glycosylation of proteins (tunicamycin) to the incubation medium, suggesting that a cytoplasmic pool of sialoglycoproteins may exist. The recovering of the EPM ofT. foetus andT. vaginalis previously treated with neuraminidase was inhibited by puromycin or tunicamycin about 40–50% and 17–30%, respectively. These observations suggest that sialoglycolipids exist on the surface of both parasite species, and that they contribute more to the surface charge ofT. vaginalis than to that ofT. foetus.