Inactivation of genes TEC1 and EFG1 in Candida albicans influences extracellular matrix composition and biofilm morphology

摘要

Background: Infections caused by Candida spp. have been associated with formation of a biofilm, i.e. a complex microstructure of cells adhering to a surface and embedded within an extracellular matrix (ECM).Methods: The ECMs of a wild-type (WT, SN425) and two Candida albicans mutant strains, Δ/Δ tec1 (CJN2330) and Δ/Δ efg1 (CJN2302), were evaluated. Colony-forming units (cfu), total biomass (mg), water-soluble polysaccharides (WSPs), alkali-soluble polysaccharides (ASPs), proteins (insoluble part of biofilms and matrix proteins), and extracellular DNA (eDNA) were quantified. Variable-pressure scanning electron microscopy and confocal scanning laser microscopy were performed. The biovolume (μm3/μm2) and maximum thickness (μm) of the biofilms were quantified using COMSTAT2.Results: ASP content was highest in WT (mean ±?SD: 74.5?±?22.0?μg), followed by Δ/Δ tec1 (44.0?±?24.1?μg) and Δ/Δ efg1 (14.7?±?5.0?μg). The protein correlated with ASPs (r?=?0.666) and with matrix proteins (r?=?0.670) in the WT st...