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Instant insight: Communicating with nature
14 May 2008
Bacteria have invented a potentially global language - quorum sensing. Kim Janda of the Scripps Research Institute in La Jolla, US, translates
The Hawaiian bobtail squid has a symbiotic relationship with a luminescent bacterium © National Science Foundation
QS has traditionally been referred to as a communication mechanism between bacteria within one species. However, research is emerging that implicates a role for QS in interspecies communication and competition, and such systems have been proposed to exist in a wide variety of bacteria. Particularly relevant to interspecies communication is the autoinducer 2 (AI-2)-based QS system, which has been suggested to function in over 50 bacterial species. Recently, it was shown that Actinomyces naeslundii and Streptococcus oralis, two bacteria responsible for oral plaque formation, require AI-2 production to initiate plaque development.
But communication amongst bacterial species is not always so cooperative; certain autoinducers and their by-products have been shown to have cytotoxic effects on other bacteria. Pseudomonas aeruginosa is especially adept at this intercellular competition, in that at least two autoinducer-derived molecules exhibit detrimental effects towards other bacteria, most notably Staphylococcus aureus. This activity may give P. aeruginosa a competitive advantage over S. aureus in the lungs of cystic fibrosis patients, a clinical setting plagued by infections due to these two pathogens.
A potential communication language between humans and Escherichia coli has also been described. E. coli responds to two human-derived small molecule signals, adrenaline and noradrenaline, to regulate virulence expression. For this same purpose, E. coli also employs a small molecule of its own production, termed AI-3. Based on the role of E. coli in the gastrointestinal tract, and the overlap between bacterial recognition of AI-3 and adrenaline, AI-3 has been suggested to play a role in maintaining intestinal homeostasis.
Because QS can mediate so many relationships, it may represent a global language that spans every kingdom of life. Human interpretation may impart a deeper knowledge of bacterial lifestyles and provide the opportunity for an appropriate response, at least one of which would be developing pharmacological interventions for bacterial infection.
Read more in the tutorial review 'Interspecies and interkingdom communication mediated by bacterial quorum sensing' in issue 7, 2008 of Chemical Society Reviews.
Link to journal article
Interspecies and interkingdom communication mediated by bacterial quorum sensing
Colin A. Lowery, Tobin J. Dickerson and Kim D. Janda, Chem. Soc. Rev., 2008, 37, 1337
Also of interest
2-Methoxycyclopentyl analogues of a Pseudomonas aeruginosa quorum sensing modulator
Lydia Y. W. Lee, Timothy Hupfield, Rebecca L. Nicholson, James T. Hodgkinson, Xianbin Su, Gemma L. Thomas, George P. C. Salmond, Martin Welch and David R. Spring, Mol. BioSyst., 2008, 4, 505