D-amino acids trigger biofilm disassembly.

Area of Science:

• Microbiology
• Bacterial Physiology
• Biochemistry

Background:

• Bacteria form complex communities called biofilms.
• Biofilms are crucial in various environments, including medical settings.
• Biofilm structure and disassembly are not fully understood.

Purpose of the Study:

• To identify factors produced by Bacillus subtilis that influence biofilm disassembly.
• To investigate the mechanism by which these factors affect biofilm structure.
• To determine if these factors are relevant to other bacterial species.

Main Methods:

• Chemical analysis to identify biofilm-disrupting factors.
• Biofilm formation and disassembly assays.
• Genetic analysis of bacterial mutants.
• Microscopy to visualize biofilm structure and amyloid fibers.

Main Results:

• A mixture of D-amino acids (D-leucine, D-methionine, D-tyrosine, D-tryptophan) was identified as a biofilm-disrupting factor.
• D-amino acids act at nanomolar concentrations.
• D-amino acids induce the release of amyloid fibers, leading to biofilm disassembly.
• Mutations in the YqxM protein prevent D-amino acid-mediated biofilm disassembly.
• D-amino acids inhibit biofilm formation in Staphylococcus aureus and Pseudomonas aeruginosa.

Conclusions:

• D-amino acids are potent inhibitors and disassemblers of bacterial biofilms.
• The mechanism involves the disruption of amyloid fiber networks essential for biofilm integrity.
• YqxM protein plays a critical role in anchoring amyloid fibers.
• D-amino acids may represent a widespread signaling mechanism for biofilm disassembly across diverse bacterial species.