Dataset Information

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 ?g/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.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC3587504 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Identification of a Pseudomonas sp. that Inhibits RHL System of Quorum Sensing.

Zhang Yuanyuan Y Zhang Yuqian Y Yang Yuxiang Y Wang Lianhui L Weng Lixing L

Indian journal of microbiology 20130125 1

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 pa ...[more]

PMID: 24426075

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Project description:Pseudomonas aeruginosa is a major nosocomial pathogen that presents high-level resistance to antibiotics. Its ability to cause infections relies on the production of multiple virulence factors. Quorum sensing (QS) regulates the expression of many of these virulence factors through three QS systems: Las, Rhl, and PQS. The Las system positively regulates the other two systems, so it is at the top of a hierarchized regulation. Nevertheless, clinical and environmental strains that lack a functional Las system have been isolated, and, surprisingly, some of them still have the ability to produce virulence factors and infect animal models, so it has been suggested that the hierarchy is flexible under some conditions or with atypical strains. Here, we analyze the PAO1 type strain and its ΔlasR-derived mutant and report, for the first time, a growth condition (phosphate limitation) where LasR absence has no effect either on virulence factor production or on the gene expression profile, in contrast to a condition of phosphate repletion where the LasR hierarchy is maintained. This work provides evidence on how the QS hierarchy can change from being a strictly LasR-dependent to a LasR-independent RhlR-based hierarchy under phosphate limitation even in the PAO1 type strain.IMPORTANCEPseudomonas aeruginosa is an important pathogen, considered a priority for the development of new therapeutic strategies. An important approach to fight its infections relies on blocking quorum sensing. The Las system is the main regulator of the quorum-sensing response, so many research efforts aim to block this system to suppress the entire response. In this work, we show that LasR is dispensable in a phosphate-limited environment in the PAO1 type strain, which has been used to define the quorum-sensing response hierarchy, and that under this condition RhlR is at the top of the regulation hierarchy. These results are highly significant, since phosphate limitation represents a similar environment to the one that P. aeruginosa faces when establishing infections.

Dataset Information

Identification of a Pseudomonas sp. that Inhibits RHL System of Quorum Sensing.

Publications

Identification of a Pseudomonas sp. that Inhibits RHL System of Quorum Sensing.

Similar Datasets

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