Differentiation of Trypanosoma brucei bloodstream trypomastigotes from long slender to short stumpy-like forms in axenic culture

An axenic cultivation system was used to study the differentiation of Trypanosoma brucei bloodstream forms from long slender to short stumpy-like forms. Trypanosomes in the logarithmic phase are similar to long slender bloodstream forms freshly isolated from infected mice, differing only in the rate of oxygen uptake. In contrast, trypanosomes in the stationary phase show a decreased level of glucose oxidation, express pyrroline-5-carboxylate reductase (proline oxidase), are inhibited in oxygen uptake to about 44% by KCN, undergo considerable morphological changes on the cellular and subcellular level, and have a significantly smaller cell volume. These results are comparable to those observed during the differentiation of long slender to short stumpy forms in infected animals, suggesting that the differentiation process towards insect procyclic forms can be initiated in culture at 37 degrees C. As judged from immunofluorescence and electron microscopy analysis, the surface coat remains intact.