title: Identification of a Pseudomonas sp. that Inhibits RHL System of Quorum Sensing.
abstract: The production of many Pseudomonas aeruginosa virulence factors and secondary metabolites is regulated in concert with cell density by quorum sensing (QS). Therefore, strategies designed to inhibit QS are promising for the control of diseases. Here, we succeeded in isolating soil bacteria (56 out of 7,000 isolates) capable of inhibiting violacein production by Chromobacterium violaceum CV026. We focused on an isolate identified as a Pseudomonas sp. based on its 16S rRNA nucleotide sequence. A partially purified inhibitor factor(s) derived from culture supernatants consisted of at least three major components by HPLC analysis. A more highly purified preparation (16 μg/ml) specifically inhibited rhl-controlled pyocyanin and rhamnolipid production by wild type P. aeruginosa PAO1 (PAO1) and a QS double mutant PAO-MW1, without affecting growth. A significant inhibitory effect on elastase, protease and biofilm was also observed. These results provide compelling evidence that the inhibitor(s) interferes with the QS system. The identities of the inhibitors remain to be established.
authors.affiliation: Laboratory of Advanced Materials, Fudan University, Shanghai, 200438 People's Republic of China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, 210046 Jiangsu People's Republic of China.
authors.forename: Yuqian
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, 210046 Jiangsu People's Republic of China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Laboratory of Advanced Materials, Fudan University, Shanghai, 200438 People's Republic of China.
authors.forename: Lianhui
authors.initials: L
authors.lastname: Wang
authors.affiliation: School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing, 210046 Jiangsu People's Republic of China.
authors.forename: Lixing
authors.initials: L
authors.lastname: Weng
keywords: Pseudomonas aeruginosa; Quorum sensing; Rhl system; Screening