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BioMed Research International
Volume 2013 (2013), Article ID 527549, 15 pages
http://dx.doi.org/10.1155/2013/527549
Research Article

Effects of Chitosan on Candida albicans: Conditions for Its Antifungal Activity

Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, 04510 México, DF, Mexico

Received 18 April 2013; Accepted 19 May 2013

Academic Editor: Isabel Sá-Correia

Copyright © 2013 Antonio Peña et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effects of low molecular weight (96.5 KDa) chitosan on the pathogenic yeast Candida albicans were studied. Low concentrations of chitosan, around 2.5 to 10 μg·mL−1 produced (a) an efflux of K+ and stimulation of extracellular acidification, (b) an inhibition of Rb+ uptake, (c) an increased transmembrane potential difference of the cells, and (d) an increased uptake of Ca2+. It is proposed that these effects are due to a decrease of the negative surface charge of the cells resulting from a strong binding of the polymer to the cells. At higher concentrations, besides the efflux of K+, it produced (a) a large efflux of phosphates and material absorbing at 260 nm, (b) a decreased uptake of Ca2+, (c) an inhibition of fermentation and respiration, and (d) the inhibition of growth. The effects depend on the medium used and the amount of cells, but in YPD high concentrations close to 1 mg·mL−1 are required to produce the disruption of the cell membrane, the efflux of protein, and the growth inhibition. Besides the findings at low chitosan concentrations, this work provides an insight of the conditions required for chitosan to act as a fungistatic or antifungal and proposes a method for the permeabilization of yeast cells.