Quorum Sensing

Certain species of bacteria naturally use quorum-sensing systems as a way of detecting cell density or to distinguish between species (Voigt, 2006). The bacteria synthesize acyl-homoserine lactones, which diffuse across the cell membrane and, at sufficiently high concentrations, signal the activation of gene expression by binding to and activating a regulatory protein (Sayut et al., 2007). The genetic components for quorum sensing have been developed into a module that can be used to incorporate cell-cell communication between bacteria into genetic circuits. In this way, quorum sensing can be used as an input for synthetic cellular logic gates.