title: Cross species quorum quenching using a native AI-2 processing enzyme.
abstract: Bacterial quorum sensing (QS) is a cell-cell communication process, mediated by signaling molecules, that alters various phenotypes including pathogenicity. Methods to interrupt these communication networks are being pursued as next generation antimicrobials. We present a technique for interrupting communication among bacteria that exploits their native and highly specific machinery for processing the signaling molecules themselves. Specifically, our approach is to bring native intracellular signal processing mechanisms to the extracellular surroundings and "quench" crosstalk among a variety of strains. In this study, the QS system based on the interspecies signaling molecule autoinducer-2 (AI-2) is targeted because of its prevalence among prokaryotes (it functions in over 80 bacterial species). We demonstrate that the Escherichia coli AI-2 kinase, LsrK, can phosphorylate AI-2 in vitro, and when LsrK-treated AI-2 is added ex vivo to E. coli populations, the native QS response is significantly reduced. Further, LsrK-mediated degradation of AI-2 attenuates the QS response among Salmonella typhimurium and Vibrio harveyi even though the AI-2 signal transduction mechanisms and the phenotypic responses are species-specific. Analogous results are obtained from a synthetic ecosystem where three species of bacteria (enteric and marine) are co-cultured. Finally, the addition of LsrK and ATP to growing co-cultures of E. coli and S. typhimurium exhibits significantly reduced native "cross-talk" that ordinarily exists among and between species in an ecosystem. We believe this nature-inspired enzymatic approach for quenching QS systems will spawn new methods for controlling cell phenotype and potentially open new avenues for controlling bacterial pathogenicity.
authors.affiliation: Department of Molecular and Cell Biology, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Varnika
authors.initials: V
authors.lastname: Roy
authors.forename: Rohan
authors.initials: R
authors.lastname: Fernandes
authors.forename: Chen-Yu
authors.initials: CY
authors.lastname: Tsao
authors.forename: William E
authors.initials: WE
authors.lastname: Bentley
mesh_terms: D018920:Coculture Techniques; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000378:metabolism* / Q000494:pharmacology; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D007783:Lactones / Q000378:metabolism*; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism* / Q000494:pharmacology; D053038:Quorum Sensing; D012486:Salmonella typhimurium / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D014733:Vibrio / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development
chemical_list: D029968:Escherichia coli Proteins; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine; C549217:LsrK protein, E coli; D017853:Phosphotransferases (Alcohol Group Acceptor)