Comparative responses of mammalian erythrocytes and microbial protoplasts to polyene antibiotics and vitamin A

Abstract

Polyene antibiotics induce the rapid lysis of rat and human erythrocytes in the presence of isotonic saline. Extent of hemolysis is dependent on the antibiotic/cell concentration ratio. Hemolysis is inhibited by serum. The effect of different osmotic stabilizers (NaCl, mannitol, sucrose) indicates that mammalian erythrocytes and Neurospora protoplasts are analogous in their response to polyene antibiotics. The results confirm the previous conclusion that the presence of sterol localized in the cell membrane is a prerequisite for sensitivity toward polyene antibiotics. The similarity of the action of these agents to that of digitonin and saponin is discussed. The polyenic compound, vitamin A, which has been shown to induce lysis of various mammalian erythrocytes, does not significantly inhibit growth of Neurospora. It also has no effect on Neurospora protoplasts in concentrations comparable to the polyene antibiotics. It does, however, promote the rapid lysis of sodium chloridestabilized B. megaterium protoplasts which are not affected by high concentrations of any polyene antibiotic. Since this bacterium does not contain sterol, it is concluded that vitamin A would not constitute an adequate model for the study of polyene antibiotic action.