Solubility and Bioactivity of the
            <i>Pseudomonas</i>
            Quinolone Signal Are Increased by a
            <i>Pseudomonas aeruginosa</i>
            -Produced Surfactant

Calfee, M. Worth; Shelton, John G.; McCubrey, James A.; Pesci, Everett C.

doi:10.1128/iai.73.2.878-882.2005

Cited by 79 publications

(69 citation statements)

References 38 publications

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“…The mechanisms by which PQS represses growth and oxygen consumption may be different. These results, along with reports of bio-activity of PQS against human cells (5,15,30) lead us to suspect that PQS has some other underlying bio-activity against bacterial cells.…”

Section: Discussionmentioning

confidence: 91%

“…In addition, it is suggested to act physically in membrane vesicle production (20,21), and has been demonstrated to chelate iron (3,11). Moreover, recent studies have demonstrated bioactivity of PQS against human cells (5,15,30). The aim of this study was to analyze the effect of PQS on bacterial species other than P. aeruginosa, with an emphasis on its effect on growth.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Effect of a Cell-to-Cell Communication Molecule, Pseudomonas Quinolone Signal (PQS), Produced by P. aeruginosa on Other Bacterial Species

et al. 2010

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One of the most important factors in the development of a bacterial community is whether the bacteria are able to grow in that habitat. The regulation of bacterial growth is generally studied in relation to physicochemical conditions, however, how bacterial communities regulate themselves remains unclear. In our previous study, it was demonstrated that a cell-to-cell communication molecule, 2-heptyl-3-hydroxy-4-quinolone, referred to as the Pseudomonas quinolone signal (PQS), affects respiring-activity in Pseudomonas aeruginosa without requiring its cognate receptor PqsR. The results suggested that PQS may affect other bacterial species, which was further examined in this study. PQS repressed the growth of several species including both Gram-negative and Gram-positive bacteria. In most cases, this effect differed from the bacteriostatic or bacteriolytic actions of antibiotics. The growth repression by PQS was inhibited when iron was added to the medium, indicating iron-chelating activity to be involved. In addition, PQS affected oxygen consumption in some species tested, and may have other underlying effects. Thus, this cell-to-cell communication molecule may influence the development of bacterial communities by regulating bacterial growth, and physicochemical factors such as iron would be important in determining its effect. Key words: Pseudomonas quinolone signal, cell-to-cell communication, interspecies interactionStudies of natural samples using techniques such as PCRdenaturing gradient gel electrophoresis (DGGE) and terminal-restriction fragment length polymorphism have provided information about the kinds of bacteria inhabiting different environments. However, why bacteria live where they do is still unclear. The regulation of growth is important when considering the habitats of bacteria, and many factors that regulate energy production have been studied, such as the presence of electron acceptors or electron donors and pH.Besides physicochemical factors, extracellular bacterial metabolites are also reported to control the growth of bacteria. For example, indole derivatives were isolated as growth inhibitors in Symbiobacterium thermophilum (35). Antibiotic reactions are another example of an interaction where bacterial growth is inhibited by extracellular bacterial metabolites. Recently, it has been proposed that antibiotics work as signals, regulating gene expression (8). Moreover, numerous bacteria utilize cell-to-cell communication signaling molecules, enabling them to coordinate diverse biological responses (27). In Gram-negative bacteria, these signaling molecules are typically N-acyl-L-homoserine lactones (AHLs). Pseudomonas aeruginosa is a well-studied bacterium possessing at least two AHL-dependent quorum-sensing systems, the LasR-LasI (las) and the RhlR-RhlI (rhl) systems (24). In addition, a non-AHL quorum-sensing signal, 2-heptyl-3-hydroxy-4-quinolone, referred to as the Pseudomonas quinolone signal (PQS), was found in P. aeruginosa (25). PQS regulates the production of virulence factors such as...

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

The Effect of a Cell-to-Cell Communication Molecule, Pseudomonas Quinolone Signal (PQS), Produced by P. aeruginosa on Other Bacterial Species

et al. 2010

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“…S7). Such concentrations would exceed the solubility of AQs in water (42), which is supported by the visual identification of aggregates using standard light microscopy (Fig. S8).…”

Section: Pqs Promotes Cell Death and Reduced Swarming For Cells Exposmentioning

confidence: 94%

Spatially dependent alkyl quinolone signaling responses to antibiotics in Pseudomonas aeruginosa swarms

Morales-Soto¹,

Dunham

Baig

et al. 2018

Journal of Biological Chemistry

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There is a general lack of understanding about how communities of bacteria respond to exogenous toxins such as antibiotics. Most of our understanding of community-level stress responses comes from the study of stationary biofilm communities. Although several community behaviors and production of specific biomolecules affecting biofilm development and associated behavior have been described for Pseudomonas aeruginosa and other bacteria, we have little appreciation for the production and dispersal of secreted metabolites within the 2D and 3D spaces they occupy as they colonize, spread, and grow on surfaces. Here we specifically studied the phenotypic responses and spatial variability of alkyl quinolones, including the Pseudomonas quinolone signal (PQS) and members of the alkyl hydroxyquinoline (AQNO) subclass, in P. aeruginosa plateassay swarming communities. We found that PQS production was not a universal signaling response to antibiotics as tobramycin elicited an alkyl quinolone response while carbenicillin did not. We also found that PQS and AQNO profiles in response to tobramycin were markedly distinct and influenced these swarms on different spatial scales. The distribution of alkyl quinolones varied by several orders of magnitude within the same swarm. At some tobramycin exposures, P. aeruginosa swarms produced alkyl quinolones in the range of 150 µM PQS and 400 µM AQNO that accumulated as aggregates.

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“…PQS is produced in the lungs of cystic fibrosis patients infected with P. aeruginosa (9) and is required for virulence in nematodes, plants, and mice (5,15,23,25,40). PQS also induces apoptosis and decreases viability in eukaryotic cells (4).…”

mentioning

confidence: 99%

Regulation ofPseudomonasQuinolone Signal Synthesis inPseudomonas aeruginosa

et al. 2005

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Pseudomonas aeruginosa is an opportunistic pathogen that causes chronic lung infections in cystic fibrosis patients and is a major source of nosocomial infections. This bacterium controls many virulence factors by using two quorum-sensing systems, las and rhl. The las system is composed of the LasR regulator protein and its cell-to-cell signal, N-(3-oxododecanoyl) homoserine lactone, and the rhl system is composed of RhlR and the signal N-butyryl homoserine lactone. A third intercellular signal, the Pseudomonas quinolone signal (PQS; 2-heptyl-3-hydroxy-4-quinolone), also regulates numerous virulence factors. PQS synthesis requires the expression of multiple operons, one of which is pqsABCDE. Previous experiments showed that the transcription of this operon, and therefore PQS production, is negatively regulated by the rhl quorum-sensing system and positively regulated by the las quorum-sensing system and PqsR (also known as MvfR), a LysR-type transcriptional regulator protein. With the use of DNA mobility shift assays and ␤-galactosidase reporter fusions, we have studied the regulation of pqsR and its relationship to pqsA, lasR, and rhlR. We show that PqsR binds the promoter of pqsA and that this binding increases dramatically in the presence of PQS, implying that PQS acts as a coinducer for PqsR. We have also mapped the transcriptional start site for pqsR and found that the transcription of pqsR is positively regulated by lasR and negatively regulated by rhlR. These results suggest that a regulatory chain occurs where pqsR is under the control of LasR and RhlR and where PqsR in turn controls pqsABCDE, which is required for the production of PQS.Pseudomonas aeruginosa is a ubiquitous gram-negative bacterium that can infect insects, plants, and animals. As an opportunistic pathogen of humans, P. aeruginosa causes acute infections in immunocompromised individuals and chronic lung infections in cystic fibrosis patients. Such infections are made possible through the production of an arsenal of virulence factors, many of which are regulated by cell-to-cell signals (see reference 36 for a review). P. aeruginosa produces at least three small compounds that function as intercellular communication signals. The acyl homoserine lactone signals, N-(3-oxododecanoyl) homoserine lactone (3-oxo-C 12 -HSL) and Nbutyryl homoserine lactone (C 4 -HSL), have been well studied and function in combination with the LuxR homologs LasR and RhlR, respectively (16,30,31,33,34). Together, these quorum-sensing signals control 6 to 11% of the P. aeruginosa genome (44, 46, 48). The third P. aeruginosa intercellular signal is a quinolone compound that was identified as 2-heptyl-3-hydroxy-4-quinolone (the Pseudomonas quinolone signal [PQS]) (37). This signal controls multiple virulence factors and is intertwined in the quorum-sensing cascade, where it appears to be a regulatory link between the las and rhl quorum-sensing systems (14,27). PQS is produced in the lungs of cystic fibrosis patients infected with P. aeruginosa (9) and is required for v...

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Solubility and Bioactivity of the Pseudomonas Quinolone Signal Are Increased by a Pseudomonas aeruginosa -Produced Surfactant

Cited by 79 publications

References 38 publications

The Effect of a Cell-to-Cell Communication Molecule, Pseudomonas Quinolone Signal (PQS), Produced by P. aeruginosa on Other Bacterial Species

The Effect of a Cell-to-Cell Communication Molecule, Pseudomonas Quinolone Signal (PQS), Produced by P. aeruginosa on Other Bacterial Species

Spatially dependent alkyl quinolone signaling responses to antibiotics in Pseudomonas aeruginosa swarms

Regulation ofPseudomonasQuinolone Signal Synthesis inPseudomonas aeruginosa

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