Conversations between bacteria
Did you know that bacteria 'talked' with each other by using small molecules to coordinate their behavior and decide when it's a good time to infect you? A recent American Chemical Society's Weekly PressPac briefly describes how UK researchers are working toward a Rosetta stone for microbes' secret language (scroll to article #3 in the PressPac). Their method, known as 'quorum sensing,' decodes 'the structure and function of compounds involved in this signaling process.' The researchers think they can now develop artificial signals to interfere with this signal process and that this could lead to new treatments for antibiotic-resistant bacteria.
The figure above shows "the quorum sensing systems of several bacteria, V. fischeri, A. tumefaciens, and P. aeruginosa, including the structures of the small AHL molecules (also known as N-acylated homoserine lactones) which are used by these bacteria. The number of carbons (Cn) in the acyl chain is indicated for clarity." (Credit: University of Cambridge, UK). Here is a link to a larger version of this figure.
Here is an explanation of the researchers in plain English. "David Spring, Martin Welch, their respective research groups and James T. Hodgkinson "explain that researchers long have known that bacteria communicate with each other. Microbes release small molecules that enable millions of individuals in a population to coordinate their behavior. Disease-causing bacteria use this language to decide when to infect a person or other host. Decoding the structure and function of compounds involved in this elaborate signaling process, known as 'quorum sensing,' could lead to new medicines to block the signals and prevent infections."
This research work has been published in ACS Chemical Biology under the title "Learning the Language of Bacteria" (Volume 2, Issue 11, Pages 715–717, November 20, 2007). Here is a link to the abstract. "Bacteria 'talk' with each other by using small molecules that enable individuals in a population to coordinate their behavior. This language is termed quorum sensing. Bacterial pathogens may use this language to decide when to attack a host organism; therefore, the development of artificial signals to interfere with this signal process has become an area of intense chemical research."
If you want to know more, the full paper is available in HTML format or in PDF format (3 pages, 208 KB). But reading it is not for everyone. Here is an excerpt. "It has become clear that bacteria mainly crowd together in highly complex, multispecies communities. Moreover, they actually 'talk' to one another by using small molecules. In Gram-negative bacteria, these small molecules are commonly N-acylated homoserine lactones (AHLs). The design and synthesis of AHL analogues have been performed by many groups (1-8) on a more or less ad hoc basis, making it difficult to draw any firm conclusions about structure-activity relationships and species selectivity. [...] This not only has unveiled a new insight into the structural similarities and differences of the AHL receptor pockets but also has identified some of the most potent synthetic modulators of quorum sensing. Moreover, this study has revealed that certain analogues display broad-spectrum activity, whereas others show marked species selectivity, thus delivering a valuable set of chemical tools to probe quorum sensing signaling."
Sources: American Chemical Society, December 5, 2007; and various websites
You'll find related stories by following the links below.