<scp>d</scp> -Amino Acids Trigger Biofilm Disassembly

TLDR

Bacteria form biofilms that naturally disassemble, and D‑amino acids produced by many bacteria may serve as a widespread signal for this disassembly. D‑amino acid treatment triggers the release of amyloid fibers that link biofilm cells together. We discovered that a nanomolar mixture of D‑leucine, D‑methionine, D‑tyrosine, and D‑tryptophan produced by Bacillus subtilis prevents biofilm formation and disassembles existing biofilms, a mechanism that also blocks biofilm formation in Staphylococcus aureus and Pseudomonas aeruginosa, and that mutants resistant to D‑amino acids have alterations in the YqxM protein required for fiber anchoring.

Abstract

Bacteria form communities known as biofilms, which disassemble over time. In our studies outlined here, we found that, before biofilm disassembly, Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine, and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofilms in the presence of D-amino acids contained alterations in a protein (YqxM) required for the formation and anchoring of the fibers to the cell. D-amino acids also prevented biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa. D-amino acids are produced by many bacteria and, thus, may be a widespread signal for biofilm disassembly.