A carbon-13 nuclear magnetic resonance analysis of the products of glucose metabolism in Leishmania pifanoi amastigotes and promastigotes

The major products of glucose metabolism were determined for amastigotes and promastigotes of Leishmania (mexicana) pifanoi under aerobic and anaerobic conditions using carbon-13 nuclear magnetic resonance. Under aerobic conditions, the major products for both forms were carbon dioxide, succinate, malate, acetate and alanine. Succinate was the dominant metabolite of promastigotes, whereas acetate and alanine were most abundant with amastigotes. Under anaerobic conditions, promastigotes produced glycerol as the dominant metabolite, along with lesser amounts of succinate, acetate and alanine; acetate and alanine remained major metabolites in amastigotes, with an increase in the relative amount of succinate and the production of some glycerol. Promastigotes generated carbon dioxide at a 5-fold greater rate than amastigotes under aerobic conditions, but this rate was reduced by more than 95% in the absence of oxygen. Amastigotes were relatively less affected by lack of oxygen and produced carbon dioxide at a rate comparable to promastigotes under anaerobic conditions. The presence of carbohydrates with a possible role in storage was detected in both promastigotes and amastigotes.