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  • 1
    ISSN: 1432-072X
    Schlagwort(e): Candida albicans ; Cell wall ; Mannoproteins ; Chitinase ; Glucanase ; Cytological distribution of chitin and mannoproteins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Different techniques released from the wall of Candida albicans mycelial cells high molecular weight mannoprotein materials with different levels of complexity. SDS solubilized among others one protein of 180 kDa which reacted with a monoclonal antibody (MAb) specific of a O-glycosylated protein secreted by regenerating mycelial protoplasts [Elorza et al. (1989) Biochem Biophys Res Commun 162:1118–1125]. Zymolyase, chitinase and β-mercaptoethanol, released different types of high molecular highly polydisperse mannoprotein materials (〉180 kDa) that also reacted with the same MAb. These materials had N-glycosidically linked sugar chains, in addition to the O-glycosidically bonded sugars, as their molecular masses were significantly reduced by Endo H digestion. Besides, the specific materials released by either zymolyase or chitinase seemed to be the same throughout the process of germ tube formation. Transmission electron microscopy of thin sections of cells and walls showed that mannoproteins and chitin are evenly distributed throughout the entire cell wall structure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-072X
    Schlagwort(e): Key words Cell wall degradation ; Ethylenediamine ; effect ; Glucan distribution ; Chitin distribution ; Candida albicans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Candida albicans cell wall components were analyzed by ethylenediamine (EDA) treatment. Based on their different solubility properties, the cell wall components produced three fractions (A, B, and C). Fractions B (EDA-soluble, water-insoluble) and C (EDA-insoluble) contained glucan, chitin, and protein in different proportions. After zymolyase (mainly a β-glucanase complex) or chitinase treatment of fractions B and C, more polysaccharides and proteins were solubilized by a second EDA treatment, suggesting that the solubility of the polymers in EDA depends on the degree of polymer interactions. Western blot analysis using two monoclonal antibodies (1B12 and 4C12) revealed electrophoretic patterns that were similar in mycelial and yeast morphologies, except that in material obtained from mycelial walls, an additional band was detected with MAb 1B12. Fluorescence microscopy of cell wall fractions treated with FITC-labeled Con-A, Calcofluor white, and FITC-labeled agglutinin showed that glucan and mannoproteins are uniformly distributed in fractions B and C, while chitin is restricted to distinct patches. Transmission electron microscopy demonstrated that fraction C maintained the original shape of the cells, with an irregular thickness generally wider than the walls. When fraction C was treated with chitinase, the morphology was still present and was maintained by an external glucan layer, with an internal expanded fibrillar material covering the entire cellular lumen. Degradation of the glucan skeleton of fraction C with zymolyase resulted in the loss of the morphology.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 149 (1988), S. 286-290 
    ISSN: 1432-072X
    Schlagwort(e): Candida albicans ; Chitin ; Mannoproteins ; Wall regeneration ; Cytochemical labelling of wall
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To assess the dynamics of synthesis of the wall by regenerating Candida albicans protoplasts deposition of chitin and mannoproteins were investigated ultrastructurally using wheat germ agglutinin conjugated with either horseradish peroxidase or colloidal gold, and Concanavalin A coupled to ferritin respectively. Freshly prepared protoplasts lacked wheat germ agglutinin receptor sites but after 1–2 h of regeneration, they were detected. After 4–5 h of regeneration, the cell wall showed a discrete structure which was only labelled with wheat germ agglutinin in thin sections. At this stage of regeneration the outermost layer of the wall was labelled with clusters of Concanavalin A-ferritin particles. After 8 h regeneration, the cell wall appeared compact, and homogenously marked with wheat germ agglutinin whereas only the surface layers appeared consistently labelled with Concanavalin A-ferritin. From these observations we conclude that C. albicans protoplasts are able to regenerate in liquid medium a cell wall consisting of a network of chitin fibrils and mannoproteins at least (glucan polymers were not determined in the present cytological study). The former are the fundamental component of the inner layers at early stages of regeneration, whereas the latter molecules are predominant in the outer layers of the wall.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1432-072X
    Schlagwort(e): Key words:Candida albicans– Mannoproteins – Tunicamycin – Concanavalin A
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. The kinectics of incorporation of two precursor mannoproteins into the regenerating cell wall of Candida albicans protoplasts have been followed at 28 °C and 37 °C using two monoclonal antibodies specific for protein epitopes (MAb 1B12 and 4C12) as probes. Both molecules were secreted from the beginning of the regeneration process, and their incorporation was retarded significantly. Analysis of the secreted materials by Western immunoblotting with MAb 1B12 allowed the identification of two closely migrating bands at apparent Mr higher than 170 kDa and significant amounts of a highly polydisperse material of even greater molecular mass. Some of these mannoproteinaceous species carried both N- and O-glycosidically linked mannose residues, as deduced from their drop in apparent Mr when synthesized in the presence of tunicamycin and by their reactivity with Concanavalin A. Following secretion, the molecules reacting with MAb 1B12 were incorporated into the regenerating walls by covalent binding. Then, when the antigen molecules were solubilized from partially regenerated walls, their mobility differed when regeneration took place at 28 °C (blastoconidia) or 37 °C (mycelial cells).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-072X
    Schlagwort(e): Candida albicans ; Cell growth ; Budding ; Mycelium ; Cell wall ; Mannoproteins ; Concanavalin A
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Depending upon growth temperature, Candida albicans can exhibit two different morphologies, a budding yeast or a mycelium. By studying the distribution of concanavalin A-ferritin particles on the cell wall surface during bud and germ tube formation, we have elucidated the way cell wall extension occurs. Both processes initially require the localized lysis of the wall in order to allow the incorporation of the newly synthesized material. Later on, the cell wall behaves as an elastic structure, allowing extension by an intosusception process and, as a consequence, cell growth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-072X
    Schlagwort(e): Candida albicans ; Mannoproteins ; Tunicamycin ; Concanavalin A
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The kinectics of incorporation of two precursor mannoproteins into the regenerating cell wall of Candida albicans protoplasts have been followed at 28°C and 37°C using two monoclonal antibodies specific for protein epitopes (MAb 1B12 and 4C12) as probes. Both molecules were secreted from the beginning of the regeneration process, and their incorporation was retarded significantly. Analysis of the secreted materials by Western immunoblotting with MAb 1B12 allowed the identification of two closely migrating bands at apparent Mr higher than 170 kDa and significant amounts of a highly polydisperse material of even greater molecular mass. Some of these mannoproteinaceous species carried both N- and O-glycosidically linked mannose residues, as deduced from their drop in apparent Mr when synthesized in the presence of tunicamycin and by their reactivity with Concanavalin A. Following secretion, the molecules reacting with MAb 1B12 were incorporated into the regenerating walls by covalent binding. Then, when the regenerating walls by covalent binding. Then, when the antigen molecules were solubilized from partially regenerated walls, their mobility differed when regeneration took place at 28°C (blastoconidia) or 37°C (mycelial cells).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1432-072X
    Schlagwort(e): Key words Transglutaminase ; Cell wall ; Candida ; albicans ; Wall epitopes ; Covalent bonds ; Protein ; interactions ; Protoplasts ; Dimorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Activity of the enzyme glutaminyl-peptide-—glutamylyl-transferase (EC 2.3.2.13; transglutaminase), which forms the interpeptidic cross-link Nε-(γ-glutamic)-lysine, was demonstrated in cell-free extracts obtained from both the yeast like and mycelial forms of Candida albicans. Higher levels of enzymatic activity were observed in the cell wall fraction, whereas the cytosol contained only trace amounts of activity. Cystamine, a highly specific inhibitor of the enzyme, was used to analyze a possible role of transglutaminase in the organization of the cell wall structure of the fungus. Cystamine delayed protoplast regeneration and inhibited the yeast-to-mycelium transition and the incorporation of proteins into the cell wall. The incorporation of covalently bound high-molecular-weight proteins into the wall was sensitive to cystamine. Proteic epitopes recognized by two monoclonal antibodies, one of which is specific for the mycelial walls of the fungus, were also sensitive to cystamine. These data suggest that transglutaminase may be involved in the formation of covalent bonds between different cell wall proteins during the final assembly of the mature cell wall.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 132 (1982), S. 144-148 
    ISSN: 1432-072X
    Schlagwort(e): Yeast ; Cell wall ; Mannoproteins ; Envelope turnover ; Concanavalin A
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract By pulse and chase labeling experiments, two independent mannoprotein pools have been found associated with the Saccharomyces cerevisiae envelope. One of them probably corresponds to mannoproteins localized in the periplasmic space. These molecules showed a high turnover rate at 28° C. The second pool is formed by intrinsic wall mannoproteins which are apparently stable for long periods of time, after a small initial turnover. These results suggest that at least part of the mannoproteins initially found in the periplasmic space may move into the wall. The time lag between the addition of the radioactive precursors and their incorporation in the cell envelope (20–30 min for amino acids and about 10 min for carbohydrate) indicates that protein formation and carbohydrate incorporation take place in succession. Moreover, bulk glycosylation of mannoproteins seems to occur close in time to the moment of secretion into the periplasmic space.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 81 (1991), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Abstract: The effect of a lipase activity (EC 3.1.1.3) on the chitin synthetase from Candida albicans has been studied, both on the active and the trypsin activated enzyme. Removal of fatty acids from acylglycerides by lipase has an inhibitory effect on the activity as well as on the ‘in vitro’ activation process by trypsin in the membrane-bound enzyme and in the chitosomes. This would indicate that an adequate lipid environment is required for both the activation process and proper function of the synthetase activity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 57 (1989), S. 0 
    ISSN: 1574-6968
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Abstract The secreted invertase (EC 3.2.1.26) of Saccharomyces cerevisiae is a glycoenzyme that contains N- and O-linked mannoses in 40/1 proportion. The small amount of mannose chains O-linked to invertase is distributed as follows: mannose (20%), mannobiose (50%), mannotriose (6%), mannotetraose (7%) and mannopentaose (17%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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