Adhesion of Candida albicans mutant strains to host tissue.
Adhesion of Candida albicans to host cells is believed to represent a fungal virulence factor and a significant step in the development of candidiasis. As C. albicans strains may differ in their in vitro adhesion ability we initiated a study to investigate whether mutant strains differ in this respect from their parent wild-type. We assessed the in vitro adhesion of C. albicans CBS562 and two mutants obtained by mutagenesis with N'-nitrosoguanidine: a histidine auxotroph, SAG5, derived from CBS562, and a respiratory-deficient strain (a petite mutant), SAR1, derived from SAG5. The adhesion was tested in vitro using two target cell systems: (1) exfoliated human buccal epithelial cells (BEC); and (2) human keratinocyte tissue line cells (HaCaT cells). Adhesion to BEC was evaluated microscopically and that to HaCaT cells by a direct ELISA technique. The results indicated a 54% reduction in adhesion to BEC for SAG5 and 30% for SAR1 as compared to the wild-type, and a 25% reduction in adhesion to HaCaT cells for SAG5 and 20% for SAR1. To verify whether the prototrophy restores the adhesion ability, we complemented the his-negative auxotroph by transforming the strain with the HIS4 gene. Then we assayed the adhesion to BEC of the complemented his-negative mutant in comparison to that of the wild-type, the his-negative mutant (SAG5) and the plasmid-cured transformant. The adhesion values of the complemented his-negative strain were similar to those of the wild-type, whereas the values of the plasmid-cured strain were similar to those of SAG5.
Department of Human Microbiology, Sackler School of Medicine, Tel-Aviv University, Israel.
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Arie
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Altboum
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Sandovsky-Losica
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D000429:Alcohol Oxidoreductases; D000619:Aminohydrolases; D002176:Candida albicans / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D002448:Cell Adhesion; D002460:Cell Line; D004847:Epithelial Cells; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D006801:Humans; D015603:Keratinocytes; D009154:Mutation; D011755:Pyrophosphatases; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics; D014774:Virulence
D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000429:Alcohol Oxidoreductases; C092116:HIS4 protein, S cerevisiae; D000619:Aminohydrolases; D011755:Pyrophosphatases