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The pseudomonas quinolone signal (PQS) balances life and death in Pseudomonas aeruginosa populations.

Häussler S, Becker T - PLoS Pathog. (2008)

Bottom Line: We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats.This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior.It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Helmholtz Center for Infection Research, Braunschweig, Germany. susanne.haeussler@helmholtz-hzi.de

ABSTRACT
When environmental conditions deteriorate and become inhospitable, generic survival strategies for populations of bacteria may be to enter a dormant state that slows down metabolism, to develop a general tolerance to hostile parameters that characterize the habitat, and to impose a regime to eliminate damaged members. Here, we provide evidence that the pseudomonas quinolone signal (PQS) mediates induction of all of these phenotypes. For individual cells, PQS, an interbacterial signaling molecule of Pseudomonas aeruginosa, has both deleterious and beneficial activities: on the one hand, it acts as a pro-oxidant and sensitizes the bacteria towards oxidative and other stresses and, on the other, it efficiently induces a protective anti-oxidative stress response. We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats. This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior. It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

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Loss of bioluminescence of P. aeruginosa PAO1 wild-type after exposure to the antibiotic ciprofloxacin.Killing of the bacteria by 5 µg/ml ciprofloxacin was significantly enhanced under the addition of PQS as opposed to HHQ (paired t-test; p value <0.05).
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ppat-1000166-g003: Loss of bioluminescence of P. aeruginosa PAO1 wild-type after exposure to the antibiotic ciprofloxacin.Killing of the bacteria by 5 µg/ml ciprofloxacin was significantly enhanced under the addition of PQS as opposed to HHQ (paired t-test; p value <0.05).

Mentions: To test this, we added synthetic PQS and the biologically less active PQS precursor 4-quinolone 2-heptyl-4-hydroxy-quinoline (HHQ) to the PAO1 wild-type harboring a luxCDABE operon in trans, and measured the decrease in bioluminescence after exposure to the antibiotic ciprofloxacin. In contrast to the addition of HHQ, killing by cirpofloxacin was significantly enhanced by the simultaneous addition of PQS (Figure 3). These results implicate that PQS but not HHQ increases bacterial sensitivity to exogenous stresses.


The pseudomonas quinolone signal (PQS) balances life and death in Pseudomonas aeruginosa populations.

Häussler S, Becker T - PLoS Pathog. (2008)

Loss of bioluminescence of P. aeruginosa PAO1 wild-type after exposure to the antibiotic ciprofloxacin.Killing of the bacteria by 5 µg/ml ciprofloxacin was significantly enhanced under the addition of PQS as opposed to HHQ (paired t-test; p value <0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2533401&req=5

ppat-1000166-g003: Loss of bioluminescence of P. aeruginosa PAO1 wild-type after exposure to the antibiotic ciprofloxacin.Killing of the bacteria by 5 µg/ml ciprofloxacin was significantly enhanced under the addition of PQS as opposed to HHQ (paired t-test; p value <0.05).
Mentions: To test this, we added synthetic PQS and the biologically less active PQS precursor 4-quinolone 2-heptyl-4-hydroxy-quinoline (HHQ) to the PAO1 wild-type harboring a luxCDABE operon in trans, and measured the decrease in bioluminescence after exposure to the antibiotic ciprofloxacin. In contrast to the addition of HHQ, killing by cirpofloxacin was significantly enhanced by the simultaneous addition of PQS (Figure 3). These results implicate that PQS but not HHQ increases bacterial sensitivity to exogenous stresses.

Bottom Line: We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats.This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior.It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Helmholtz Center for Infection Research, Braunschweig, Germany. susanne.haeussler@helmholtz-hzi.de

ABSTRACT
When environmental conditions deteriorate and become inhospitable, generic survival strategies for populations of bacteria may be to enter a dormant state that slows down metabolism, to develop a general tolerance to hostile parameters that characterize the habitat, and to impose a regime to eliminate damaged members. Here, we provide evidence that the pseudomonas quinolone signal (PQS) mediates induction of all of these phenotypes. For individual cells, PQS, an interbacterial signaling molecule of Pseudomonas aeruginosa, has both deleterious and beneficial activities: on the one hand, it acts as a pro-oxidant and sensitizes the bacteria towards oxidative and other stresses and, on the other, it efficiently induces a protective anti-oxidative stress response. We propose that this dual function fragments populations into less and more stress tolerant members which respond differentially to developing stresses in deteriorating habitats. This suggests that a little poison may be generically beneficial to populations, in promoting survival of the fittest, and in contributing to bacterial multi-cellular behavior. It further identifies PQS as an essential mediator of the shaping of the population structure of Pseudomonas and of its response to and survival in hostile environmental conditions.

Show MeSH
Related in: MedlinePlus