Characterization of the recombinant Candida albicans β-1,2-mannosyltransferase that initiates the β-mannosylation of cell wall phosphopeptidomannan

2013 ◽  
Vol 457 (2) ◽  
pp. 347-360 ◽  
Author(s):  
Emeline Fabre ◽  
Ghenima Sfihi-Loualia ◽  
Marilyne Pourcelot ◽  
Bernadette Coddeville ◽  
Frédéric Krzewinski ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Immunocompromised Patients ◽  
Serious Infections ◽  
Antigenic Factor

Candida albicans is a yeast responsible for serious infections in immunocompromised patients. In the present paper, we report the identification of an enzyme that initiates the synthesis of a bioactive cell wall carbohydrate antigenic factor, the β-mannans.

scholarly journals Characterization of Monolaurin Resistance in Enterococcus faecalis

2007 ◽  
Vol 73 (17) ◽  
pp. 5507-5515 ◽  
Author(s):  
Muriel Dufour ◽  
Janet M. Manson ◽  
Philip J. Bremer ◽  
Jean-Pierre Dufour ◽  
Gregory M. Cook ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Enterococcus Faecalis ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Wall Structure ◽  
Transmission Electron ◽  
Serious Infections ◽  
Autolytic Activity

ABSTRACT There is increasing concern regarding the presence of vancomycin-resistant enterococci in domestically farmed animals, which may act as reservoirs and vehicles of transmission for drug-resistant enterococci to humans, resulting in serious infections. In order to assess the potential for the use of monolaurin as a food preservative, it is important to understand both its target and potential mechanisms of resistance. A Tn917 mutant library of Enterococcus faecalis AR01/DGVS was screened for resistance (MIC, >100 μg/ml) to monolaurin. Three mutants were identified as resistant to monolaurin and were designated DGRM2, DGRM5, and DGRM12. The gene interrupted in all three mutants was identified as traB, which encodes an E. faecalis pheromone shutdown protein and whose complementation in trans restored monolaurin sensitivity in all three mutants. DGRM2 was selected for further characterization. E. faecalis DGRM2 showed increased resistance to gentamicin and chloramphenicol (inhibitors of protein synthesis), while no difference in the MIC was observed with the cell wall-active antibiotics penicillin and vancomycin. E. faecalis AR01/DGVS and DGRM2 were shown to have similar rates (30% cell lysis after 4 h) of cell autolytic activity when activated by monolaurin. Differences in cell surface hydrophobicity were observed between the wild type and the mutant, with the cell surface of the parent strain being significantly more hydrophobic. Analysis of the cell wall structure of DGRM2 by transmission electron microscopy revealed an increase in the apparent cell wall thickness and contraction of its cytoplasm. Taken together, these results suggest that the increased resistance of DGRM2 was due to a change in cell surface hydrophobicity, consequently limiting the diffusion of monolaurin to a potential target in the cytoplasmic membrane and/or cytoplasm of E. faecalis.

Characterization of a major cell wall antigen and potential adhesin in three strains of Candida albicans

1994 ◽  
Vol 162 (1-2) ◽  
pp. 33-40
Author(s):  
W. Jenq ◽  
Chi Lan Chen ◽  
Chun Chang ◽  
Richard F. E. Crang
Keyword(s):  
Cell Wall ◽  
Candida Albicans

scholarly journals Kinetic and thermodynamic characterization of the interactions between the components of human plasma kinin-forming system and isolated and purified cell wall proteins of Candida albicans

2015 ◽  
Vol 62 (4) ◽  
pp. 825-835 ◽  
Author(s):  
Karolina Seweryn ◽  
Justyna Karkowska-Kuleta ◽  
Natalia Wolak ◽  
Oliwia Bochenska ◽  
Sylwia Kedracka-Krok ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Human Plasma ◽  
Cell Wall Proteins ◽  
Thermodynamic Characterization ◽  
Plasma Kinin

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

Synthesis of 3,6-branched oligomannoside fragments of the mannan from Candida albicans cell wall corresponding to the antigenic factor 4

2010 ◽  
Vol 345 (10) ◽  
pp. 1283-1290 ◽  
Author(s):  
Alexander A. Karelin ◽  
Yury E. Tsvetkov ◽  
Lucia Paulovičová ◽  
Slavomír Bystrický ◽  
Ema Paulovičová ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antigenic Factor

LL37 and hBD-3 elevate the β-1,3-exoglucanase activity of Candida albicans Xog1p, resulting in reduced fungal adhesion to plastic

2012 ◽  
Vol 441 (3) ◽  
pp. 963-970 ◽  
Author(s):  
Hao-Teng Chang ◽  
Pei-Wen Tsai ◽  
Hsin-Hui Huang ◽  
Yu-Shu Liu ◽  
Tzu-Shan Chien ◽  
...  
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Antimicrobial Peptides ◽  
Organ Transplant ◽  
Vaginal Candidiasis ◽  
Immunocompromised Patients ◽  
Fungal Adhesion ◽  
Oral Thrush ◽  
Dose Dependent

The opportunistic fungus Candida albicans causes oral thrush and vaginal candidiasis, as well as candidaemia in immunocompromised patients including those undergoing cancer chemotherapy, organ transplant and those with AIDS. We previously found that the AMPs (antimicrobial peptides) LL37 and hBD-3 (human β-defensin-3) inhibited C. albicans viability and its adhesion to plastic. For the present study, the mechanism by which LL37 and hBD-3 reduced C. albicans adhesion was investigated. After AMP treatment, C. albicans adhesion to plastic was reduced by up to ~60% and was dose-dependent. Our previous study indicated that LL37 might interact with the cell-wall β-1,3-exoglucanase Xog1p, which is involved in cell-wall β-glucan metabolism, and consequently the binding of LL37 or hBD-3 to Xog1p might cause the decrease in adhesion. For the present study, Xog1p(41–438)-6H, an N-terminally truncated, active, recombinant construct of Xog1p and Xog1p fragments were produced and used in pull-down assays and ELISA in vitro, which demonstrated that all constructs interacted with both AMPs. Enzymatic analyses showed that LL37 and hBD-3 enhanced the β-1,3-exoglucanase activity of Xog1p(41–438)-6H approximately 2-fold. Therefore elevated Xog1p activity might compromise cell-wall integrity and decrease C. albicans adhesion. To test this hypothesis, C. albicans was treated with 1.3 μM Xog1p(41–438)-6H and C. albicans adhesion to plastic decreased 47.7%. Taken together, the evidence suggests that Xog1p is one of the LL37/hBD-3 targets, and elevated β-1,3-exoglucanase activity reduces C. albicans adhesion to plastic.

scholarly journals RBR1, a Novel pH-Regulated Cell Wall Gene of Candida albicans, Is Repressed by RIM101 and Activated by NRG1

2004 ◽  
Vol 3 (3) ◽  
pp. 776-784 ◽  
Author(s):  
Henrike Lotz ◽  
Kai Sohn ◽  
Herwig Brunner ◽  
Fritz A. Mühlschlegel ◽  
Steffen Rupp
Keyword(s):  
Cell Wall ◽  
Candida Albicans ◽  
Transcriptional Profiling ◽  
Hyphal Growth ◽  
Additional Cell ◽  
A Cell ◽  
Acidic Conditions ◽  
Ph Dependent ◽  
Glycosylphosphatidyl Inositol

ABSTRACT The transcription factor Rim101p of Candida albicans has been shown to play a major role in pH-dependent gene regulation. Rim101p is involved in cell wall biosynthesis, since it regulates PHR1 and PHR2, two almost functionally redundant cell wall glycosidases important for adaptation to either neutral or acidic habitats within the human host. To identify additional cell wall components regulated by Rim101p, we performed transcriptional profiling with a cell wall-specific DNA microarray. We showed that Rim101p contributes to the activation of known hypha-specific genes such as HWP1 and RBT1 but is also required for repression of the previously uncharacterized potential cell wall genes RBR1, RBR2, and RBR3. Further characterization of RBR1 revealed that it encodes a small glycosylphosphatidyl inositol protein that is expressed under acidic conditions predominantly at low temperature. Deletion of the gene resulted in a filamentation defect at low pH. Most interestingly, NRG1, a transcriptional repressor of hyphal growth in C. albicans, was required for RBR1 expression. The apparently activating effect of NRG1 observed in this study has not been described before. In addition, we showed that expression of NRG1 is not only temperature but also pH dependent.

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