CYTOTOXIC EFFECTS OF THE KILLER TOXIN KTCf20 AGAINST Candida spp.

FERNANDEZ DE ULLIVARRI M.; BULACIOS G.A.; BELLOMIO A.

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

Killer yeasts are able to produce proteins or glycoproteins withantimicrobial activity known as killer toxins, and they can be usedas biocontrol agents against pathogens yeasts. In previous studies,we demonstrated the glucanase activity of the killer toxin KTCf20,produced by Wickerhamomyces anomalus Cf20. In this study, weevaluated the cytotoxic effects of KTCf20, present in cell-free supernatant (CFS), over two clinical isolates of pathogenic strains ofCandida spp.Growth inhibition of C. albicans and C. tropicalis in W. anomalusCf20 CFS (2×104 aU/ml), was studied at different temperatures (20and 30 ºC) and NaCl concentrations (0 and 1%). OD600 and cellviability were measured to calculate inhibition. Fluorescence microscopy (FM) of pathogenic strains was performed after incubation for 2h at 20 ºC in CFS+NaCl 1% and live/dead staining using SYTO9 andPI as fluorescent probes. Transmission electron microscopy (TEM)was also performed to evaluate the cytotoxic effects of CFS on Candida cells. In every experiment, heat-inactivated CFS (100 ºC, 15min) was used as control.CFS produced a growth inhibition of 74 and 80%, and 1-2 log cfu/