Induction of heat shock and stress proteins in promastigotes of three Leishmania species.

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Abstract
The induction of heat shock proteins in 3 spp. of Leishmania, L. tropica, L. enrietti and L. donovani is reported. When culturs of promastigotes are shifted from 26.degree. to 37.degree. or 40.degree. C, the synthesis of proteins with apparent MW of 88,000, 74,000 and 54,000 is stimulated. Actinomycin D added just prior to the shift prevented the appearance of these proteins but had no effect when present 30 min after the transfer onward, suggesting that the regulation of leishmanial heat shock proteins occurs at the transcriptional level. Exposure of L. tropica promastigotes to sodium arsenite elicits the synthesis of 3 major and 4 minor polypeptides. Their apparent MW are, respectively, 94,000, 78,000 and 56,000, and 70,000, 45,000, 22,000 and 18,000. The response of Leishmania organisms to heat shock and to sodium arsenite is similar to that of other organisms, but some of the proteins identified as stress proteins in the parasite differ in size. The heat shock proteins might play a role in cytodifferentiation during the life cycle of the parasite and also in cellular adaptation to higher temperatures.