Psd1 Effects on Candida albicans Planktonic Cells and Biofilms

Abstract

<i>Candida albicans</i> is an important human pathogen, causing opportunistic infections. The adhesion of planktonic cells to a substrate is the first step for biofilm development. The antimicrobial peptide (AMP) <i>Ps</i>d1 is a defensin isolated from <i>Pisum sativum</i> seeds. We tested the effects of this AMP on <i>C. albicans</i> biofilms and planktonic cells, comparing its activity with amphotericin B and fluconazole. Three <i>C. albicans</i> variants were studied, one of them a mutant deficient in glucosylceramide synthase, conferring resistance to <i>Ps</i>d1 antifungal action. Atomic force microscopy (AFM) was used to assess morphological and biomechanical changes on fungal cells. Surface alterations, with membrane disruption and leakage of cellular contents, were observed. Cytometry assays and confocal microscopy imaging showed that <i>Ps</i>d1 causes cell death, in a time and concentration-dependent manner. These results demonstrate <i>Ps</i>d1 pleiotropic action against a relevant fungal human pathogen, suggesting its use as natural antimycotic agent.