Bdsf C. Albicans Biofilm Formation

Candida is an important opportunistic human fungal pathogen. Infections caused by C. albicans are related to the formation of a biofilm, which enhances the resistance of the C. albicans defense system, increases its resistance to antifungal drugs, and induces increase drug tolerance. Therefore, it makes clinical care more challenging. The in vitro activities of cis-BDSF (cis-2-dodecenoic acid) and trans-BDSF (trans-2-dodecenoic acid) against Candida albicans growth, germ tube germination and biofilm formation were estimated by optical density and microscopic assessment. C. albicans biofilms were prepared using the static microtitre plate model. The quantitative analysis of formation of biofilm was performed by XTT [2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide] reduction assay to evaluate the effect of different concentrations of cis-BDSF and trans-BDSF at different times. The reduction in biofilm structure and formation was visualized by inverted microscopy. Northern blot was employed to estimate the mRNA expression levels of the hyphae specific gene HWP1. We found that at 300μM, cis-BDSF and trans-BDSF inhibited yeast growth and reduced germ tube formation by 70%. At 300μM, by exogenous addition at 0 and 1 h, cis-BDSF and trans-BDSF reduced biofilm formation by about 90%(0 h) and 60%(1 h) and were more effective against biofilm formation than farnesol and DSF (cis-11-methyl-2-dodecenoic acid). However, none of the four drugs were able to destroy pre-formed biofilms. Northern blot showed that the mRNA expression levels of HWP1, were down regulated after cis-BDSF or trans-BDSF treatment. ALSo real-time RT-PCR analysis showed that both HWP1 and ALS3 were down regulated bycis-BDSF (90%)andtrans-BDSF (70-80%) at 60μM, demonstrating that cis-BDSF and trans-BDSF can strongly block biofilm formation in C. albicansby interfering with the morphological switch and the adhesion of hypha, and ALSo conbined with the inhibition of the yeast growth at higher concentration (300μM). The results suggest that they may be potential therapeutic agent worthy of further study.