METABOLIC STUDIES BY H-1-NMR OF DIFFERENT FORMS OF TRYPANOSOMA-CRUZI AS OBTAINED BY IN-VITRO CULTURE

By culturing Trypanosoma cruzi epimastigotes in modified Grace's mediu m with 10% foetal bovine serum, a significant quantity of metacyclic f orms could be obtained. Transformation was observed after 8 days of cu lture, with metacyclic forms reaching 75%. Cultured Vero cells were in fected with metacyclic forms and maintained until free-amastigote form s were obtained. Additionally, amastigote-like forms could be obtained by subjecting metacyclic cultures to heat shock. Parasites were grown with glucose as the major carbon source. The metabolites produced and excreted during culture were identified by difference proton nuclear magnetic resonance spectroscopy and quantified by enzymatic methods. T he final products of glucose catabolism differed not only quantitative ly but also qualitatively for the three major life-cycle stages of T. cruzi. The end products of metabolism produced by epimastigote forms w ere mainly acetate and pyruvate and, to a lesser extend, L-alanine and ethanol. Differences between epimastigotes and metacyclic forms were only quantitative. However, free amastigotes as well as amastigote-lik e forms, excreted acetate, glycerol, and pyruvate and to a lesser exte nt succinate, but no L-alanine or ethanol.