AN ULTRASTRUCTURE STUDY OF THE IN-VITRO EFFECTS OF L-LEUCINE METHYL-ESTER AND AMMONIUM-CHLORIDE ON TRYPANOSOMA-CRUZI EPIMASTIGOTES

Trypanosoma cruzi epimastigotes were subjected to the lysosomotropic a gents L-leucine methyl ester and ammonium chloride to determine their effects on the ultrastructure of the parasite. The lysosomotropic agen ts applied to epimastigotes caused a time-dependent alteration in the morphology of the cells marked by a 5-fold increase in the number of l ysosomes. Continued exposure to ammonium chloride caused slight disrup tion of the reservosomes. The amino acid ester, however, while causing the parasite to swell after prolonged exposure (e.g., 24 h), had litt le effect on the reservosomes, the kinetoplast, or even the mitochondr ion. A specific inhibitor of cysteine proteinases provided some protec tion for lysosomes from the effects of the amino acid ester. Although it is agreed that reservosomes are similar to endosomes, no lysosomal fusion with the reservosomes was observed. Acid phosphatase activity w as observed only in lysosomes.