Paracoccidioides brasileensis: Cell wall structure and virulence

San-Blas, Gioconda; San-Blas, Felipe

doi:10.1007/bf01259396

Cited by 96 publications

(60 citation statements)

References 31 publications

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“…In the present study, the gene encoding b-glucan synthase ( fks) was among those P. brasiliensis genes that were down-regulated in response to the macrophage environment. It has been shown for P. brasilieneis [20] and other fungi [21], that virulence of different isolates in experimental mouse infection is related to the relative amounts of a-glucan to b-glucan present in the cell wall of these fungi (i.e., the cell wall of avirulent yeast isolates contains less a-glucan and more b-glucan). The apparent mechanism of b-glucan host protection may be related to its capacity to stimulate the production of several inflammatory mediators, including tumor necrosis factor alpha (TNF-a).…”

Section: Discussionmentioning

confidence: 99%

Early transcriptional response of Paracoccidioides brasiliensis upon internalization by murine macrophages

Tavares

Silva

Dantas

et al. 2007

Microbes and Infection

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Section: Discussionmentioning

confidence: 99%

Early transcriptional response of Paracoccidioides brasiliensis upon internalization by murine macrophages

Tavares

Silva

Dantas

et al. 2007

Microbes and Infection

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“…In Paracoccidiodes brasiliensis (29), Histoplasma capsulatum (30), and Blastomyces dermatitidis (31), mutants deficient in a-1,3-glucan are avirulent. In cerulenin-resistant mutants of C. albicans, alteration of mannan structure is correlated with reduced adherence (32) and virulence (33).…”

Section: Discussionmentioning

confidence: 99%

Attenuated virulence of chitin-deficient mutants of Candida albicans.

Bulawa

Miller

Henry

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

140

123

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We have analyzed the role of chitin, a cellwall polysaccharide, in the virulence of Candida albicans. Mutants with a 5-fold reduction in chitin were obtained in two ways: (i) by selecting mutants resistant to Calcofluor, a fluorescent dye that binds to chitin and inhibits growth, and(ii) by disrupting CHS3, the C. albicans homolog of CSD2/ CALJ/DITIOI/KT12, a Saccharomyces cereviswe gene required for synthesis of '90% of the cell-wall chitin. A key step in the development of an antifungal drug is the determination of its efficacy. For practical reasons, much of the initial testing is done in culture (in vitro), where the test conditions differ markedly from the conditions encountered by a fungal pathogen during infection (in vivo). The limited ability of in vitro testing to accurately predict in vivo efficacy is illustrated by the azoles, which are highly effective in vivo despite modest fungicidal activity in vitro (1). Thus, it is possible that some fungal components are required for pathogenicity in vivo but not for growth in vitro. Possible virulence determinants include factors required for recognition and invasion of the host and for protection against host defense systems. Because the cell wall is involved in these processesthe wall protects the fungal cell from external injury and cell-wall components mediate adherence (2-4) and immune response (5-8)-changes in cell-wall structure and/or composition may affect virulence.We have begun to investigate the role of the cell-wall polysaccharide chitin in the virulence of Candida albicans. Chitin is found in all true fungi; therefore agents that inhibit chitin synthesis are potential broad-spectrum antifungal drugs. In the past decade, many of the genes involved in chitin synthesis have been isolated in Saccharomyces cerevisiae, and, more recently, the homologs of these genes have been identified in C. albicans (9-11).In S. cerevisiae, three chitin synthases have been detected (for review, see refs. 12 and 13). One of them, chitin synthase III, makes 90% of the cell-wall chitin. At least three genes, CSD2/CALl/DIT101/KT12, CSD4/CAL2, and CAL3, are required for this activity. Mutants lacking this enzyme are chitin-deficient and, consequently, are resistant to Calcofluor, a fluorescent dye that binds to chitin and inhibits growth by disrupting microfibril assembly (14, 15).Like S. cerevisiae, C. albicans has at least three chitin synthases (9-11). Recently, the C. albicans homolog of CSD2, designated CHS3, was cloned and sequenced (11). By analogy to S. cerevisiae, C. albicans CHS3 mutants should be chitindeficient and Calcofluor-resistant. In the present report, we show that chitin-deficient mutants of C. albicans obtained by two methods are significantly less virulent than the wild-type strain. . Media were supplemented with uridine at 0.1 mg/ml as required. Agar (2%, Difco) was added for solid media. Urdauxotrophs were selected on medium containing 5-fluoroorotic acid (5-FOA) as described (16). Germ-tube formation was induced in 20% fetal bovine serum ...

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“…The most striking are an increase in chitin content and a shift in the anomeric structure of most (but not all) alkali insoluble ␤-glucans to alkali soluble ␣-glucans [10]. Chemical composition analysis of P. brasiliensis isolated cell wall preparations showed that mycelial phase cells have higher protein content (24-41%) than yeast cells (7-14%) [11].…”

Section: Introductionmentioning

confidence: 99%

Proteome of cell wall-extracts from pathogenic Paracoccidioides brasiliensis: Comparison among morphological phases, isolates, and reported fungal extracellular vesicle proteins

Longo

Cunha

Sobreira

et al. 2014

EuPA Open Proteomics

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Cell wall proteins Yeast Mycelium DTT Extracellular vesicles a b s t r a c tWe identified non-covalently linked cell wall proteins from Paracoccidioides brasiliensis yeasts and mycelia, with focus on the yeast pathogenic phase, and correlated them with reported fungal extracellular vesicle proteins. We studied isolates Pb3 and Pb18, which evoke distinct patterns of experimental paracoccidioidomycosis and represent two phylogenetic groups.Proteins were extracted mildly with dithiothreitol, trypsinized, and peptides analyzed by liquid chromatography coupled to high-resolution mass spectrometry. Among 132 yeastexclusive sequences, 92 were Pb18-exclusive. About 80% of total proteins were classified as secretory, mostly showing non-conventional signals. Extracellular vesicular transportation could be involved, since 60% had orthologs reported in fungal extracellular vesicles.

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Paracoccidioides brasileensis: Cell wall structure and virulence

Cited by 96 publications

References 31 publications

Early transcriptional response of Paracoccidioides brasiliensis upon internalization by murine macrophages

Early transcriptional response of Paracoccidioides brasiliensis upon internalization by murine macrophages

Attenuated virulence of chitin-deficient mutants of Candida albicans.

Proteome of cell wall-extracts from pathogenic Paracoccidioides brasiliensis: Comparison among morphological phases, isolates, and reported fungal extracellular vesicle proteins

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