The Evolution Of Quorum Sensing In Bacterial Biofilms

Main Category: Biology / Biochemistry
Also Included In: Infectious Diseases / Bacteria / Viruses
Article Date: 28 Jan 2008 - 17:00 PDT

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Bacteria are increasingly recognized as highly interactive organisms with complex social lives, which are critical to their capacity to cause disease. In particular, many species inhabit dense, surface-bound communities, termed biofilms, within which they communicate and respond to local cell density through a process known as quorum sensing. Enormous effort has been devoted to understanding the genetics and biochemistry of biofilm formation and quorum sensing, but how and why they evolve remains virtually unexplored.

Many bacteria use quorum sensing to regulate the secretion of sticky extracellular slime, an integral feature of biofilm life. Intriguingly, however, some species turn on slime production at high cell density, while others turn it off. In this week's issue of the open-access journal PLoS Biology, Carey Nadell, Kevin Foster, and colleagues show that by using an individual-based model of biofilm growth, they  investigated why different species use quorum sensing to control slime production in opposite ways. The secret underlying this variation appears to reside in the nature of infections.

Turning slime on at high cell density can allow one strain to suffocate another when competition is intense, as occurs in long-lived chronic infections. Meanwhile, turning slime secretion off at high cell density can benefit a strain causing an acute infection by allowing rapid growth before departing the host.

The evolution of quorum sensing in bacterial biofilms.
Nadell CD, Xavier JB, Levin SA, Foster KR (2008)
PLoS Biol 6(1): e14. doi:10.1371/journal.pbio.0060014
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