Disruption of protein synthesis as antifungal mode of action by chitosan

The antimicrobial activity of chitosan has been acknowledged for more than 30 years and yet its mode-of-action remains ambiguous. We analyzed chemical-genetic interactions of low-molecular weight chitosan using a collection of approximate to 4600 S. cerevisiae deletion mutants and found that 31% of the 107 mutants most sensitive to chitosan had deletions of genes related primarily to functions involving protein synthesis. Disruption of protein synthesis by chitosan was substantiated by an in vivo beta-galactosidase expression assay suggesting that this is a primary mode of antifungal action. Analysis of the yeast gene deletion array and secondary assays also indicate that chitosan has a minor membrane disruption effect - a leading model of chitosan antimicrobial activity. (C) 2013 Elsevier B.V. All rights reserved.