scholarly journals Contribution of Phospholipomannan to the Surface Expression of β-1,2-Oligomannosides in Candida albicans and Its Presence in Cell Wall Extracts

2002 ◽  
Vol 70 (8) ◽  
pp. 4323-4328 ◽  
Author(s):  
D. Poulain ◽  
C. Slomianny ◽  
T. Jouault ◽  
J. M. Gomez ◽  
P. A. Trinel
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Candida Albicans ◽  
Fluorescence Microscopy ◽  
Cell Surface ◽  
Western Blotting ◽  
Surface Expression ◽  
Solid Media ◽  
Protective Antibodies ◽  
Complex Expression

ABSTRACT β-1,2-Oligomannosides (β-1,2-Man) derived from Candida albicans mannan have been shown to act as adhesins and to induce protective antibodies. We used monoclonal antibodies specific for β-1,2-Man in electron, confocal, and fluorescence microscopy to study the surface expression of β-1,2-Man epitopes. These monoclonal antibodies were also used for Western blotting of cell surface extracts to study the nature of the molecules expressing the β-Man epitopes. Evidence was obtained for the contribution of a glycolipid, phospholipomannan (PLM), to the complex expression of β-1,2-Man epitopes at the cell wall surfaces of yeasts grown on solid media. PLM was present in intercellular matrixes of colonies grown on agar and was detected as a contaminant in mannan batches prepared by conventional methods.

scholarly journals Characterization of Candida albicans cell wall antigens with monoclonal antibodies.

1993 ◽  
Vol 61 (11) ◽  
pp. 4842-4847 ◽  
Author(s):  
J Ponton ◽  
A Marot-Leblond ◽  
P A Ezkurra ◽  
B Barturen ◽  
R Robert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Candida Albicans

scholarly journals Msb2 Signaling Mucin Controls Activation of Cek1 Mitogen-Activated Protein Kinase in Candida albicans

2009 ◽  
Vol 8 (8) ◽  
pp. 1235-1249 ◽  
Author(s):  
Elvira Román ◽  
Fabien Cottier ◽  
Joachim F. Ernst ◽  
Jesús Pla
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Protein Kinase ◽  
Osmotic Shock ◽  
Mitogen Activated Protein Kinase ◽  
Hog Pathway ◽  
High Osmolarity ◽  
Cell Wall Biogenesis ◽  
Solid Media ◽  
Mitogen Activated Protein

ABSTRACT We have characterized the role that the Msb2 protein plays in the fungal pathogen Candida albicans by the use of mutants defective in the putative upstream components of the HOG pathway. Msb2, in cooperation with Sho1, controls the activation of the Cek1 mitogen-activated protein kinase under conditions that damage the cell wall, thus defining Msb2 as a signaling element of this pathway in the fungus. msb2 mutants display altered sensitivity to Congo red, caspofungin, zymolyase, or tunicamycin, indicating that this protein is involved in cell wall biogenesis. Msb2 (as well as Sho1 and Hst7) is involved in the transmission of the signal toward Cek1 mediated by the Cdc42 GTPase, as revealed by the use of activated alleles (Cdc42G12V) of this protein. msb2 mutants have a stronger defective invasion phenotype than sho1 mutants when tested on certain solid media that use mannitol or sucrose as a carbon source or under hypoxia. Interestingly, Msb2 contributes to growth under conditions of high osmolarity when both branches of the HOG pathway are altered, as triple ssk1 msb2 sho1 mutants (but not any single or double mutant) are osmosensitive. However, this phenomenon is independent of the presence of Hog1, as Hog1 phosphorylation, Hog1 translocation to the nucleus, and glycerol accumulation are not affected in this mutant following an osmotic shock. These results reveal essential functions in morphogenesis, invasion, cell wall biogenesis, and growth under conditions of high osmolarity for Msb2 in C. albicans and suggest the divergence and specialization of this signaling pathway in filamentous fungi.

scholarly journals The effect of farnesol on amino acid incorporation by a wild-type and cell-wall variant strain ofCandida albicans

2005 ◽  
Vol 51 (8) ◽  
pp. 715-718 ◽  
Author(s):  
Phyllis C Braun
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Amino Acid ◽  
Quorum Sensing ◽  
Cell Surface ◽  
Wild Type ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Ofcandida Albicans ◽  
Density Growth

Farnesol, a quorum sensing (QS) signal, is produced by Candida albicans during high density growth and has been found to inhibit morphogenesis. This QS auto-inducing signal was discovered to increase amino acid incorporation by C. albicans when concentrations of farnesol increased to 10 µg/mL in yeast nitrogen broth. Farnesol concentrations greater than 10 µg/mL abolished the enhanced incorporation, and the magnitude of the increased incorporation was dependent on cell-surface hydrophobicity.Key words: Candida albicans, farnesol, amino acid incorporation.

scholarly journals β-1,2- and α-1,2-LinkedOligomannosides Mediate Adherence of Candida albicansBlastospores to Human Enterocytes InVitro

2003 ◽  
Vol 71 (12) ◽  
pp. 7061-7068 ◽  
Author(s):  
Fredéric Dalle ◽  
Thierry Jouault ◽  
Pierre André Trinel ◽  
Jacques Esnault ◽  
Jean Maurice Mallet ◽  
...  
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Candida Albicans ◽  
Digestive Tract ◽  
Intestinal Epithelium ◽  
Invasive Candidiasis ◽  
Wall Surface ◽  
Dimorphic Yeast ◽  
Dose Dependent Decrease ◽  
Dose Dependent

ABSTRACT Candida albicans is a commensal dimorphic yeast of the digestive tract that causes hematogenously disseminated infections in immunocompromised individuals. Endogenous invasive candidiasis develops from C. albicans adhering to the intestinal epithelium. Adherence is mediated by the cell wall surface, a domain composed essentially of mannopyranosyl residues bound to proteins, the N-linked moiety of which comprises sequences of α-1,2- and β-1,2-linked mannose residues. β-1,2-linked mannosides are also associated with a glycolipid, phospholipomannan, at the C. albicans surface. In order to determine the roles of β-1,2 and α-1,2 oligomannosides in the C. albicans-enterocyte interaction, we developed a model of adhesion of C. albicans VW32 blastospores to the apical regions of differentiated Caco-2 cells. Preincubation of yeasts with monoclonal antibodies (MAbs) specific for α-1,2 andβ -1,2 mannan epitopes resulted in a dose-dependent decrease in adhesion (50% of the control with a 60-μg/ml MAb concentration). In competitive assays β-1,2 and α-1,2 tetramannosides were the most potent carbohydrate inhibitors, with 50% inhibitory concentrations of 2.58 and 6.99 mM, respectively. Immunolocalization on infected monolayers with MAbs specific forα -1,2 and β-1,2 oligomannosides showed that these epitopes were shed from the yeast to the enterocyte surface. Taken together, our data indicate that α-1,2 and β-1,2 oligomannosides are involved in the C. albicans-enterocyte interaction and participate in the adhesion of the yeasts to the mucosal surface.

Hydrophobic cell wall protein glycosylation by the pathogenic fungus Candida albicans

1994 ◽  
Vol 40 (4) ◽  
pp. 266-272 ◽  
Author(s):  
Kevin C. Hazen ◽  
Pati M. Glee
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Cell Surface ◽  
Molecular Mass ◽  
Pathogenic Fungus ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Protein Glycosylation ◽  
Yeast Cells ◽  
Cell Wall Proteins

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, β-mannosidase, N-glycosidase F), an exoglycosidase (α-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.Key words: Candida albicans, cell wall, mannoproteins, hydrophobicity, fibrils.

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