Potent and selective synthetic modulators of a quorum sensing repressor in Pseudomonas aeruginosa identified from second-generation libraries of N-acylated L-homoserine lactones. (73/173)

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Characterization of N-acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger) rhizosphere: co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia. (74/173)

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Diversity and functional analysis of luxS genes in vibrios from marine sponges Mycale laxissima and Ircinia strobilina. (75/173)

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SdiA sensing of acyl-homoserine lactones by enterohemorrhagic E. coli (EHEC) serotype O157:H7 in the bovine rumen. (76/173)

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Roles of Pseudomonas aeruginosa autoinducers and their degradation products, tetramic acids, in bacterial survival and behavior in ecological niches. (77/173)

Pseudomonas aeruginosa, an opportunistic pathogen, is known to mainly use N-acylhomoserine lactones (AHLs) as autoinducers. Recent progress in this field demonstrated that not only AHLs, but also their degradation products, tetramic acids, may have some biological activities. The present study examined the roles of Pseudomonas autoinducers and tetramic acids in bacterial survival and behavior in ecological niches. P. aeruginosa autoinducers and the tetramic acid derivatives were chemically synthesized, and the structure-activity correlation was investigated. Some tetramic acids derived from AHLs caused a significant reduction in the viability of P. aeruginosa in a concentration dependent manner (30-300 microM). The smaller the inoculum of bacteria, the stronger the bactericidal activity that was observed. The data from tetramic acid derivatives indicated the keto-enol structure of tetramic acid to be critical for the antibacterial activity. Exogenous tetramic acid did not induce significant changes in the formation of biofilm or production of exoproducts such as pyocyanin and elastase. Tetramic acid and disinfectants acted synergistically to kill P. aeruginosa. These results suggest the AHL-degradation product tetramic acid to be useful for bacterial control.  (+info)

Degradation of N-acylhomoserine lactone quorum sensing signaling molecules by potato root surface-associated Chryseobacterium strains. (78/173)

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signaling molecules by many Gram-negative bacteria. Here, 413 bacterial strains were obtained from the roots of potato plants and screened for AHL-degrading bacteria using Chromobacterium violaceum reporter strains. Sixty one isolates degraded N-hexanoyl-L-homoserine lactone (C6-HSL) within 24 h. Based on their 16S rRNA gene sequences, most of these isolates were assigned to the genus Chryseobacterium and divided into eight groups. Most of the strains degraded N-decanoyl-L-homoserine lactone (C10-HSL) and were active against 3-oxo-substituted AHLs. Groups V and VI were more effective at inactivating AHLs. One group V strain, StRB402, showed putative AHL-lactonase activity. This is the first report of AHL-degrading Chryseobacterium strains.  (+info)

Signaling-mediated cross-talk modulates swarming and biofilm formation in a coral pathogen Serratia marcescens. (79/173)

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Immunomodulatory and protective roles of quorum-sensing signaling molecules N-acyl homoserine lactones during infection of mice with Aeromonas hydrophila. (80/173)

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