Regulation of antimicrobial peptide production by autoinducer-mediated quorum sensing in lactic acid bacteria.

Several lactic acid bacteria produce peptides with antimicrobial activity. During the last few years, cell-cell communication has emerged as the key regulatory mechanism that controls the production of many of these antimicrobial peptides via a regulatory strategy denominated quorum sensing. Quorum sensing allows populationwide synchronised production of antimicrobial peptides as a function of cell density. The cell-cell communication phenomenon required for sensing of the cell density is mediated by secreted signalling molecules. These 'molecular messengers' accumulate in the environment as the cell density increases and activate signal transduction cascades that result in the production of antimicrobial peptides by the stimulated bacterial cell.