[Trypanosome sensitivity to polyene antibiotics].

Swelling of the plasma membrane is one of the mechanisms of resistance to damages in pathogenic Protozoa. Polyenic antibiotics induce reconstruction of the cytoplasma membrane of unicellular eukaryotic organisms, i. e. fungi and Protozoa by binding the membrane lipids. The effect of 5 heptaene polyenic antibiotics, such as amphotericin B, mycoheptin, levorin, its sodium salt and levoridone on the growth of trypanosomides of Trypanosoma lewisi and Crithidia oncopelti was studied. The MIC and IC50 of these antibiotics were determined. It was found that these antibiotics were inhibitors of the trypanosomide growth and development. Levorin and amphotericin were most active with respect to C. oncopelti and levorin was most active with respect to T. lewisi. Physiological and morphological changes in the trypanosomides induced by the polyenic antibiotics were noted. The effect of levorin and amphotericin B on the content of lipids in the trypanosomide cells was studied. A decrease in the total content of the intracellular lipids due to the effect of the polyenes was shown. Differences in the rate of the inhibitory effect as dependent on the structure of the hydrophile part of the lactone ring of the heptaene polyenic antibiotics were found.