From unicellular properties to multicellular behavior: bacteria quorum sensing circuitry and applications.

Cell-cell communication and coordinated population-based behavior among single cell organisms have gained considerable attention in the recent years. The ability to send, receive, and process information allows unicellular organisms to act as multicellular entities and increases their chances of survival in complex environments. Quorum sensing (QS), a density-dependent cell-signaling mechanism, is one way by which bacteria 'talk' to one another. QS is commonly associated with adverse health effects such as biofilm formation, bacteria pathogenicity, and virulence. But there exists great potential to harness QS circuitry and its properties for other applications, enabling even wider societal impact. Interesting avenues are envisioned for the detection of chemicals and pathogens, the navigation of interspecies communication, the synchronization and control of cell phenotype, and the creation of novel materials based on synthetic biology. In this review, we first highlight the recent discoveries of the molecular underpinnings of QS function, with emphasis on the formation of biofilms. We then discuss how researchers have used QS circuitry to their advantage to build synthetic networks, rewire native metabolic pathways, and engineer cells for a variety of applications.