Community participation in biofilm matrix assembly and function

Area of Science:

• Microbiology
• Biochemistry
• Mycology

Background:

• Biofilms of Candida albicans fungi produce an extracellular matrix.
• This matrix is crucial for adherence and resistance to antifungal drugs.
• Major polysaccharide components include α-mannan, β-1,6 glucan, and β-1,3 glucan.

Purpose of the Study:

• To investigate the roles of α-mannan, β-1,6 glucan, and β-1,3 glucan in Candida albicans biofilm matrix structure and function.
• To determine if matrix biogenesis is coordinated at the cellular or community level.

Main Methods:

• Genetic manipulation of polysaccharide synthesis/export pathways.
• Biochemical analysis of matrix composition.
• Pharmacological assays for drug sequestration.
• Biofilm coculture experiments with mutant strains.

Main Results:

• Interference with any single polysaccharide constituent affected the levels of the others.
• All three polysaccharides were necessary for matrix function, including fluconazole sequestration.
• Coculturing matrix-defective mutants restored mature matrix structure, composition, and drug resistance.

Conclusions:

• Matrix biogenesis in Candida albicans biofilms involves coordinated delivery of polysaccharides.
• Functional matrix production is coordinated extracellularly, reflecting cooperative community actions.