Relation between cell wall chitin content and susceptibility to amphotericin B in Kluyveromyces, Candida and Schizosaccharomyces species.

Yeast strains belonging to the genera Candida, Kluyveromyces and Schizosaccharomyces were tested for their susceptibility (or resistance) to amphotericin B (AmB) in relation to their cell wall chitin content. Results showed that membrane sterol contents did not enable us to explain resistance or susceptibility of these yeasts to AmB. Indeed, we noted that resistant strains were as rich in ergosterol as sensitive strains. The suppression of the wall of yeasts induced an increase in susceptibility to AmB. Strains with high cell wall chitin content were more sensitive to this polyenic antifungal agent than strains with low chitin content. Growth of the yeasts in the presence of chitin induced a resistance of the yeasts to AmB. Similar results were obtained after treatment of the cells by chitinase. In contrast, growth of the yeasts in the presence of chitin synthase activators induced high susceptibility to AmB. Yeast cell wall chitin is an aminopolysaccharide, usually at low concentrations. In Schizosaccharomyces pombe its presence was not established. This polymer is associated with glucans in the wall matrix of the lateral wall and in the budding scars. Even at low content, this polymer seems to play an essential role in the sensitivity (or resistance) of yeast cells to AmB.