Detection and characterization of two antigens specific for cell walls ofCandida albicans mycelial growth phase

Leusch, Hans-Georg

doi:10.1007/bf01568941

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…Whether the mannosyl groups of C. albicans can be similarly divided is not known, but our results suggest that the size of mannosyl chains on different mannoproteins can be substantially different (20-fold or more). This suggestion is consistent with previous studies of different mannoproteins produced by C. albicarls (Leusch 1989;Herrero et al 1987;Marcilla et al 1991) and with the differential conA reactivity of F 2 versus F6 proteins observed in the present study.…”

Section: Discussionmentioning

confidence: 99%

Hydrophobic cell wall protein glycosylation by the pathogenic fungus Candida albicans

Hazen¹,

Glee²

1994

Can. J. Microbiol.

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Cell surface hydrophobicity influences adhesion and virulence of the opportunistic fungal pathogen Candida albicans. Previous studies have shown that cell surface hydrophobicity is due to specific proteins that are exposed on hydrophobic cells but are masked by long fibrils on hydrophilic cells. This observation suggests that hydrophobic cell wall proteins may contain little or no mannosylation. In the present study, the glycosylation levels of three hydrophobic cell wall proteins (molecular mass range between 36 and 40 kDa) derived from yeast cells were examined. One hydrophilic protein (90 kDa) was also tested. Various endoglycosidases (endoglycosidase F-N-glycosidase F, O-glycosidase, beta-mannosidase, N-glycosidase F), an exoglycosidase (alpha-mannosidase), and trifluoromethane sulfonic acid were used to deglycosylate the proteins. All four proteins were reactive to the lectin concanavalin A, demonstrating that they were mannoproteins. However, gel electrophoresis of the control and treated proteins revealed that mannosyl groups of hydrophobic proteins were less than 2 kDa in size, while the mannosyl group of the hydrophilic protein had a molecular mass of approximately 20 kDa. These results suggest that unlike many hydrophilic proteins, hydrophobic proteins may have low levels of glycosylation. Changes in glycosylation may determine exposure of hydrophobic protein regions at the cell surface.

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Section: Discussionmentioning

confidence: 99%

Hydrophobic cell wall protein glycosylation by the pathogenic fungus Candida albicans

Hazen¹,

Glee²

1994

Can. J. Microbiol.

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“…It was quite possible that the same fungus growing in wood as opposed to growing in liquid culture might show differences in cell wall structure and/or composition that would reduce or abolish its detection by a particular antibody. Differences in expression of fungal cell surface/wall antigens have been shown to occur depending on : (a) whether growth was in vitro or in vivo (Brawner & Cutler, 1987); (b) culture conditions such as the type and concentration of nitrogen source used, the amount of the inoculum, and the age of the mycelium (Burrell et al, 1966); and (c) the phase of fungal growth (Smail & Jones, 1984 ;Sundstrom et al, 1987 ;Leusch, 1989 ;Casanova et al, 1989). In our work, we also noted a difference in the detection of the antigens recognized by monoclonals 6A5 and 3F12 on mycelia grown in liquid culture.…”

Section: Discussionmentioning

confidence: 99%

Monoclonal antibodies to Gliocladium roseum, a potential biological control fungus of sap-staining fungi in wood

Breuil

Luck²,

Rossignol³

et al. 1992

Journal of General Microbiology

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Immunological probes were developed to discriminate between a potential biological control fungus and sapstaining fungi present in wood. This paper describes the production of monoclonal antibodies to isolated cell wall fragments of the biological control fungus Gliocladium roseum. Two monoclonals, designated 6A5 and 3F12, were characterized. Their specificity was assessed by ELISA, by immunogold silver staining light microscopy, by immunogold electron microscopy, and by immunoblotting. Monoclonal 6A5 specifically recognized G. roseum and closely related species and did not react with any of 21 sap-staining fungi tested. Monoclonal 3F12 recognized most of the biological control fungi tested and also showed reactivity with two of the 21 sap-staining fungi. Both monoclonals appeared to recognize carbohydrate epitopes of the cell wall in G. roseum. Although the antibodies were produced against the cell wall of fungus grown in liquid culture, they also detected specific fungi in wood and, therefore, can be used for studies of wood colonization by fungi and for investigations of the interactions between different fungi growing on wood.

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“…Lipase treatment utilized 2 mg of lipase and 0.2 mg of phospholipase A 2 in 1 ml of TBS, pH 7, and 10 mM CaCl 2 , at 37°C for 2 h with agitation (21). Protease treatment utilized 10 mg of Pronase, 2 mg of proteinase K, and 10 mg of protease from S. griseus in 1 ml of TBS with 10 mM DTT, at 24°C for 2 h with agitation (19,22). Acid hydrolysis utilized 1 ml of 2 M HCl at 100°C for 2 h (19).…”

Section: Reagents-calcofluormentioning

confidence: 99%

Cell Wall Biogenesis of Blastomyces dermatitidis

Brandhorst¹,

Klein

2000

Journal of Biological Chemistry

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Pathogenic yeast of Blastomyces dermatitidis express a surface protein adhesin, WI-1. Due to the crucial role of WI-1 in adherence and disease pathogenesis, we investigated how the protein localizes to the surface of B. dermatitidis. WI-1 released extracellularly by wild-type yeast coated the surfaces of co-cultured knockout yeast within 3 h of incubation, implying that secreted WI-1 provides a pathway for loading the protein onto the yeast cell wall. In radioligand binding assays, purified WI-1 bound saturably, specifically, and with high affinity (K d ‫؍‬ 8.3 ؋ 10 ؊9 ) to the cell surface of knockout yeast devoid of WI-1. WI-1 added exogenously, in vitro, to knockout yeast was indistinguishable from native cell surface WI-1 by fluorescence staining and restored adhesivity to the knockout yeast in macrophage binding and phagocytosis assays. Analysis of interactions between WI-1 and elements of the yeast cell wall identified chitin as the anchor point for WI-1. This interaction was shown to hinge on the 24-amino acid tandem repeat sequence of WI-1. Efforts to extract surface WI-1 from the yeast demonstrated that it is fastened to the wall by non-covalent interactions and covalent links between cysteine residues. We conclude that the yeast cell surface adhesin WI-1 localizes to the cell wall, in part, through extracellular release followed by high affinity binding back onto exposed chitin fibrils. These findings point to a novel pathway of cell wall biogenesis in yeast and an unanticipated role for chitin in anchoring and displaying a surface adhesin and virulence determinant.Blastomyces dermatitidis is a dimorphic fungal pathogen that infects human and animal hosts via the inhalation of airborne conidia or hyphal fragments from soil (1). At the elevated temperature of 37°C in a host, the fungus undergoes a phase transition to the pathogenic yeast form. A 120-kDa protein on the cell wall of B. dermatitidis yeast, designated WI-1, plays a crucial role in the establishment of pulmonary infection and its dissemination to visceral organs (2). WI-1 promotes yeast adherence to and phagocytosis by macrophages through binding of CD11b/CD18 and CD14 receptors (3). Structurally, the WI-1 adhesin consists of a short amino-terminal region, a 24-amino acid repeat, which is present in 30 copies and arrayed in tandem within the core of the protein, and a carboxyl-terminal region that has homology to epidermal growth factor (4). According to Chou-Fasman predictions (5, 6), the tandem repeats in the core of the protein are likely to assume an ␣-helical conformation, suggesting a tendency toward an elongated overall structure. WI-1 contains few small amino acid residues (4), which supports the notion that it may adopt a rod-like configuration due to a reduced flexibility. It contains 95 residues of tyrosine and an impressive 146 residues of tryptophan (4), representing a substantial metabolic investment by B. dermatitidis. WI-1 also has 90 cysteine residues, 2 within each tandem repeat, which could be involved in covalent bonding ...

show abstract

Detection and characterization of two antigens specific for cell walls ofCandida albicans mycelial growth phase

Cited by 14 publications

References 15 publications

Hydrophobic cell wall protein glycosylation by the pathogenic fungus Candida albicans

Hydrophobic cell wall protein glycosylation by the pathogenic fungus Candida albicans

Monoclonal antibodies to Gliocladium roseum, a potential biological control fungus of sap-staining fungi in wood

Cell Wall Biogenesis of Blastomyces dermatitidis

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