INDUCTION OF STRESS PROTEINS IN THE PLANT TRYPANOSOME PHYTOMONAS-CHARACIAS

The present study of the synthesis of new proteins in plant trypanosom atids in the genus Phytomonas as a response to different types of stre ss demonstrates the production of a number of proteins that can be gro uped into four families similar to those that appear in other organism s (heat-shock proteins). In the study of stress, Phytomonas cultures w ere subjected to changes in temperature from 22 degrees to 37 degrees C, deprived of glucose, grown in the presence of sodium arsenite, and treated with calcium ionophore. In addition, the culture medium was ch anged from Grace's medium (330 mosmol/l) to a plant-culture medium wit h an osmolarity of 286 mosmol/l, implying the exertion of stress durin g the parasite's normal biological cycle of passage from the insect ve ctor to the plant host. The treatment with actinomycin D demonstrated that some of the mRNAs that codify these proteins are found in normal presynthesized conditions. To measure the effect of temperature on the macromolecule biosynthesis we compared the incorporation of labeled a nalogues ([H-3]-thymidine, [H-3]-uridine, and [H-3]-leucine) by flagel lates cultured at 22 degrees C with that by parasites cultivated at 37 degrees C.