Effect of aculeacin A on reverting protoplasts of Candida albicans.

Protoplasts of Candida albicans were prepared by digestion with Zymolyase and the effect of aculeacin A, a wall-active antibiotic, on the synthesis of microfibrillar structures by the protoplasts incubated for 5 hr in an osmotically stabilized medium was studied using several electron microscopical techniques. Chemical analyses of the protoplasts before and after reversion with or without the antibiotic were also performed. Aculeacin A not only inhibited synthesis of microfibrils mainly composed of alkali-insoluble beta-glucan, but also their assembly to form thicker bundles. The antibiotic appeared to have no effect on other wall components constituting the surface structure of reverting protoplasts. These data confirmed our previous postulation that aculeacin A is a specific and potent inhibitor of beta-glucan synthesis as well as biogenesis of cell walls including beta-glucans in susceptible yeasts.