The Interaction of Amphotericin B Methyl Ester with Protoplasts of Candida albicans

Abstract
The interaction of amphotericin B methyl ester (AME) with protoplasts of C. albicans was measured indirectly by following the incorporation of [U-14C]phenylalanine into the acid-indirectly material. The inhibitory effects of AME at the minimum inhibitory concentration were prevented by the addition of 85 mM KCl and 45 mM MgCl2, as shown previously for Saccharomyces cerevisiae. In C. albicans, pretreatment of the yeast before antibiotic addition was unnecessary. KCl and MgCl2 did not prevent AME from binding to the protoplast membrane. This interaction was reversed by incubating the protoplasts in the presence of the protecting salts.