Methods for Analysis of Bacterial Autoinducer‐2 Production

AbstractQuorum sensing is a cell‐cell signaling process that many bacteria use to regulate gene expression as a function of the density of the population. This phenomenon involves the production, release, and response to small chemical molecules termed autoinducers. Most autoinducers are species‐specific; however, one autoinducer called autoinducer‐2 (AI‐2) is produced and detected by many species of bacteria and thus can foster inter‐species communication. This unit describes two assays to detect and quantify AI‐2 from biological samples. The first uses a bacterial reporter strain, which produces bioluminescence in response to AI‐2. The second is an in vitro assay based on a modified version of an AI‐2 receptor fused to a cyan fluorescent protein and a yellow fluorescent protein. Binding of AI‐2 to this fusion protein induces a dose‐dependent decrease in fluorescence resonance energy transfer (FRET), enabling quantification of the AI‐2 concentration in the samples. Curr. Protoc. Microbiol. 23:1C.1.1‐1C.1.15. © 2011 by John Wiley & Sons, Inc.