Publications (32) View all
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Article: Members 5 and 6 of the Candida albicans BMT family encode enzymes acting specifically on β-mannosylation of the phospholipomannan cell-wall glycosphingolipid.
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ABSTRACT: A family of nine genes encoding proteins involved in the synthesis of β-1,2 mannose adhesins of Candida albicans has been identified. Four of these genes, BMT1-4, encode enzymes acting stepwise to add β-mannoses on to cell-wall phosphopeptidomannan (PPM). None of these acts on phospholipomannan (PLM), a glycosphingolipid member of the mannose-inositol-phosphoceramide family, which contributes with PPM to β-mannose surface expression. We show that deletion of BMT5 and BMT6 led to a dramatic reduction of PLM glycosylation and accumulation of PLM with a truncated β-oligomannoside chain, respectively. Disruptions had no effect on sphingolipid biosynthesis and on PPM β-mannosylation. β-Mannose surface expression was not affected, confirming that β-mannosylation is a process based on specificity of acceptor molecules, but liable to global regulation.Glycobiology 06/2012; 22(10):1332-42. · 3.58 Impact Factor -
Article: New regulators of biofilm development in Candida glabrata.
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ABSTRACT: Biofilm formation plays an important role in fungal pathogenesis. In this work, we used a genetic screen in order to identify and characterize genes involved in the formation of biofilms by the opportunistic fungal pathogen Candida glabrata. We identified the Cst6p transcription factor as a negative regulator of the EPA6 gene that encodes an adhesin central to C. glabrata biofilm formation. Analysis of single and double mutant strains showed that Cst6p acts in a pathway independent of the Yak1/Sir4 pathway also known to regulate expression of EPA6 and consequently biofilm formation. In contrast, we showed that the chromatin remodelling Swi/Snf complex positively regulates biofilm formation in C. glabrata. RT-qPCR experiments demonstrated that EPA6 expression, and thus biofilm formation, depends on the integrity of the Sir complex. Finally, we showed that Swi/Snf-dependent regulation of biofilm formation is adhesin-specific.Research in Microbiology 03/2012; 163(4):297-307. · 2.76 Impact Factor -
Article: Murine model of dextran sulfate sodium-induced colitis reveals Candida glabrata virulence and contribution of β-mannosyltransferases.
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ABSTRACT: Candida glabrata, like Candida albicans, is an opportunistic yeast pathogen that has adapted to colonize all segments of the human gastrointestinal tract and vagina. The C. albicans cell wall expresses β-1,2-linked mannosides (β-Mans), promoting its adherence to host cells and tissues. Because β-Mans are also present in C. glabrata, their role in C. glabrata colonization and virulence was investigated in a murine model of dextran sulfate sodium (DSS)-induced colitis. Five clustered genes of C. glabrata encoding β-mannosyltransferases, BMT2-BMT6, were deleted simultaneously. β-Man expression was studied by Western blotting, flow cytometry, and NMR analysis. Mortality, clinical, histologic, and colonization scores were determined in mice receiving DSS and different C. glabrata strains. The results show that C. glabrata bmt2-6 strains had a significant reduction in β-1,2-Man expression and a disappearance of β-1,2-mannobiose in the acid-stable domain. A single gavage of C. glabrata wild-type strain in mice with DSS-induced colitis caused a loss of body weight, colonic inflammation, and mortality. Mice receiving C. glabrata bmt2-6 mutant strains had normal body weight and reduced colonic inflammation. Lower numbers of colonies of C. glabrata bmt2-6 were recovered from stools and different parts of the gastrointestinal tract. Histopathologic examination revealed that the wild-type strain had a greater ability to colonize tissue and cause tissue damage. These results showed that C. glabrata has a high pathogenic potential in DSS-induced colitis, where β-Mans contribute to colonization and virulence.Journal of Biological Chemistry 01/2012; 287(14):11313-24. · 4.77 Impact Factor -
Article: A murine model of dextran sulfate sodium-induced colitis reveals Candida glabrata virulence and contribution of β-Mannosyltransferases
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ABSTRACT: Candida glabrata, like Candida albicans, is an opportunistic yeast pathogen that has adapted to colonize all segments of the human gastrointestinal tract and vagina. The C. albicans cell wall expresses β−1,2−linked mannosides (β−Mans) promoting its adherence to host cells and tissues. As β−Mans are also present in C. glabrata, their role in C. glabrata colonization and virulence was investigated in a murine model of dextran sulfate sodium (DSS)−induced colitis. Five clustered genes of C. glabrata encoding β−mannosyltransferases, BMT2−BMT6, were deleted simultaneously. β−Man expression was studied by Western blotting, flow cytometry and NMR analysis. Mortality, clinical, histologic, and colonization scores were determined in mice receiving DSS and different C. glabrata strains. The results show that C. glabrata bmt2−6 strains had a significant reduction in β−1,2 Man expression and a disappearance of β−1,2 mannobiose in the acid-stable domain. A single gavage of C. glabrata wild-type strain in mice with DSS−induced colitis caused a loss of body weight, colonic inflammation, and mortality. Mice receiving C. glabrata bmt2-6 mutant strains had normal body weight and reduced colonic inflammation. Lower numbers of colonies of C. glabrata bmt2−6 were recovered from stools and different parts of the gastrointestinal tract. Histopathologic examination revealed that the wild−type strain had a greater ability to colonize tissue and cause tissue damage. These results showed that C. glabrata has a high pathogenic potential in DSS−induced colitis where β−Mans contribute to colonization and virulence.Journal of Biological Chemistry 01/2012; · 4.77 Impact Factor -
Article: Biofilm formation studies in microtiter plate format.
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ABSTRACT: Although Candida biofilms have been clearly identified as playing an increasingly important role in human disease, their biology and the reason for their poor susceptibility to antifungal agents remain largely unknown. Over recent years, various models have been developed in order to better characterize Candida biofilms. Here, we describe a number of rapid, inexpensive microtiter-format techniques and strategies which can be used for large-scale screening procedures aimed at identifying genes involved in Candida biofilm formation and/or potential antifungal agents with activity against pathogen cells growing under these conditions. The procedures could also be easily adapted for studying biofilm structures with a range of microscopy techniques.Methods in molecular biology (Clifton, N.J.) 01/2012; 845:369-77.
