[Trypanosome sensitivity to polyene antibiotics]

Area of Science:

• Microbiology
• Parasitology
• Biochemistry

Background:

• Pathogenic Protozoa utilize plasma membrane swelling as a defense mechanism.
• Polyenic antibiotics interact with membrane lipids, inducing structural changes in unicellular eukaryotes like fungi and Protozoa.

Purpose of the Study:

• To investigate the inhibitory effects of five heptaene polyenic antibiotics on the growth of Trypanosoma lewisi and Crithidia oncopelti.
• To determine the minimum inhibitory concentration (MIC) and IC50 values for these antibiotics.
• To analyze the physiological, morphological, and lipid content changes in trypanosomides induced by these antibiotics.

Main Methods:

• Cultivation of Trypanosoma lewisi and Crithidia oncopelti.
• Determination of MIC and IC50 values for amphotericin B, mycoheptin, levorin, its sodium salt, and levoridone.
• Microscopic examination for physiological and morphological changes.
• Biochemical analysis of intracellular lipid content.

Main Results:

• All tested polyenic antibiotics inhibited trypanosomide growth and development.
• Levorin and amphotericin B exhibited the highest activity against Crithidia oncopelti, while levorin was most potent against Trypanosoma lewisi.
• Significant physiological and morphological alterations were observed in the treated trypanosomides.
• A reduction in total intracellular lipid content was demonstrated following antibiotic treatment.
• The rate of inhibition varied based on the hydrophile structure of the antibiotic's lactone ring.

Conclusions:

• Heptaene polyenic antibiotics are effective inhibitors of trypanosomide growth.
• Levorin and amphotericin B show promise as potential therapeutic agents against these protozoan parasites.
• Antibiotic-induced changes in membrane lipid composition are a key factor in their mechanism of action.
• Structural modifications of polyenic antibiotics can influence their efficacy.