Null mutants of Candida albicans for cell-wall-related genes form fragile biofilms that display an almost identical extracellular matrix proteome.
By two-dimensional gel electrophoresis (2-DE) and mass spectrometry, we have characterized the polypeptide species present in extracts obtained by 60% ethanol treatment of whole mature (48 h) biofilms formed by a reference strain (CAI4-URA3) and four Candida albicans null mutants for cell-wall-related genes (ALG5, CSA1, MNN9 and PGA10) Null mutants form fragile biofilms that appeared partially split and weakly attached to the substratum contrary to those produced by the reference strain. An almost identical, electrophoretic profile consisting of about 276 spots was visualized in all extracts examined. Proteomic analysis led to the identification of 131 polypeptides, corresponding to 86 different protein species, being the rest isoforms-83 displayed negative hydropathic indexes and 82 lack signal peptide. The majority of proteins appeared at pI between 4 and 6, and molecular mass between 10 and 94 kDa. The proteins identified belonged to the following Gene Ontology categories: 21.9% unknown molecular function, 16.2% oxidoreductase activity, 13.3% hydrolase activity and 41.8% distributed between other different GO categories. Strong defects in biofilm formation appreciated in the cell-wall mutant strains could be attributed to defects in aggregation due to abnormal cell wall formation rather than to differences in the biofilm extracellular matrix composition.
Department of Microbiology and Ecology, School of Pharmacy, University of Valencia, 46100 Burjasot, Valencia, Spain.
José P
JP
Martínez
Department of Microbiology and Ecology, School of Pharmacy, University of Valencia, 46100 Burjasot, Valencia, Spain.
Rosario
R
Blanes
Department of Microbiology and Ecology, School of Pharmacy, University of Valencia, 46100 Burjasot, Valencia, Spain.
Manuel
M
Casanova
Department of Microbiology and Ecology, School of Pharmacy, University of Valencia, 46100 Burjasot, Valencia, Spain.
Eulogio
E
Valentín
Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Valencia, 46100 Burjasot, Valencia, Spain.
Amelia
A
Murgui
Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca, Spain ado@usal.es.
Ángel
Á
Domínguez
D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000737:chemistry* / Q000235:genetics* / Q000502:physiology; D002473:Cell Wall / Q000235:genetics*; D015180:Electrophoresis, Gel, Two-Dimensional; D005109:Extracellular Matrix / Q000737:chemistry*; D005656:Fungal Proteins / Q000032:analysis*; D017353:Gene Deletion; D005800:Genes, Fungal; D013058:Mass Spectrometry; D020543:Proteome / Q000032:analysis*
D005656:Fungal Proteins; D020543:Proteome
ALG5; CSA1; Candida albicans; MNN9; biofilm; cell wall-related genes; PGA10; extracellular matrix; null mutants; proteomic analysis