Involvement of a cell wall receptor in the mode of action of an anti-Candida toxin of Pichia anomala.

Hanes-Woolf, Dixon, and Hill plots of growth rates of Candida albicans RC1 grown in various concentrations of glucose and a Pichia anomala WC65 toxin suggested the presence of toxin-binding sites. Indirect immunofluorescence microscopy with antitoxin antibodies demonstrated binding of the toxin to the cell wall. Resistance to the toxin of a mutant Saccharomyces cerevisiae deficient in cell wall beta-1-6-D-glucan suggests that the glucan either served as the receptor or influenced the number or composition of the receptor. Immunofluorescence that appeared to be associated with the cell membrane of toxin-treated spheroplasts of C. albicans was also observed. Spheroplasts of the resistant mutant of S. cerevisiae were sensitive to the toxin.