EFFECTS OF TEMPERATURE ON PROMASTIGOTES OF SEVERAL SPECIES OF LEISHMANIA

Six Leishmania species were studied comparatively, in order to determi ne the influence of temperature ''in vitro'' on differentiation, infec tivity and protein synthesis. Differentiation ocurred in a heterogeneo us manner, even in species that produce similar clinical manifestation s. Thus, no association could be found between thermosensitivity and d isease. The association between expression of proteins and increasing temperatures was analyzed at 34 degrees C by polyacrylamide gel electr ophoresis with sodium dodecyl sulphate (SDS-PAGE), using different inc ubation times, and employing a technique involving metabolic incorpora tion of [S-35]-methionine. Protein synthesis was very similar in all t he New World species apart from L. amazonensis, which expressed a prot ein of approximately 80 kDa when incubated at 34 degrees C for 2 hours . All the tested species had in common the expression of a 70 kDa prot ein. Differences, however, were observed in relation to the time inter val for protein expression. In L. chagasi, synthesis was detected afte r 30 minutes of incubation at 34 degrees C, while L. braziliensis requ ired 1 hour at the same temperature. The ''in vivo'' and ''in vitro'' infectivity of the differentiated forms was also analyzed, but no sign ificant differences were observed.