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Stringent response activates quorum sensing and modulates cell density-dependent gene expression in Pseudomonas aeruginosa.
J Bacteriol. 2001 Sep; 183(18):5376-84.JB

Abstract

During nutrient starvation, Escherichia coli elicits a stringent response involving the ribosome-associated protein RelA. Activation of RelA results in a global change in the cellular metabolism including enhanced expression of the stationary-phase sigma factor RpoS. In the human pathogen Pseudomonas aeruginosa, a complex quorum-sensing circuitry, linked to RpoS expression, is required for cell density-dependent production of many secreted virulence factors, including LasB elastase. Quorum sensing relies on the activation of specific transcriptional regulators (LasR and RhlR) by their corresponding autoinducers (3-oxo-C(12)-homoserine lactone [HSL] and C(4)-HSL), which function as intercellular signals. We found that overexpression of relA activated the expression of rpoS in P. aeruginosa and led to premature, cell density-independent LasB elastase production. We therefore investigated the effects of the stringent response on quorum sensing. Both lasR and rhlR gene expression and autoinducer synthesis were prematurely activated during the stringent response induced by overexpression of relA. Premature expression of lasR and rhlR was also observed when relA was overexpressed in a PAO1 rpoS mutant. The stringent response induced by the amino acid analogue serine hydroxamate (SHX) also led to premature production of the 3-oxo-C(12)-HSL autoinducer. This response to SHX was absent in a PAO1 relA mutant. These findings suggest that the stringent response can activate the two quorum-sensing systems of P. aeruginosa independently of cell density.

Authors+Show Affiliations

Department of Genetics and Microbiology, University of Geneva Medical School, CH-1211 Geneva 4, Switzerland.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

11514523

Citation

van Delden, C, et al. "Stringent Response Activates Quorum Sensing and Modulates Cell Density-dependent Gene Expression in Pseudomonas Aeruginosa." Journal of Bacteriology, vol. 183, no. 18, 2001, pp. 5376-84.
van Delden C, Comte R, Bally AM. Stringent response activates quorum sensing and modulates cell density-dependent gene expression in Pseudomonas aeruginosa. J Bacteriol. 2001;183(18):5376-84.
van Delden, C., Comte, R., & Bally, A. M. (2001). Stringent response activates quorum sensing and modulates cell density-dependent gene expression in Pseudomonas aeruginosa. Journal of Bacteriology, 183(18), 5376-84.
van Delden C, Comte R, Bally AM. Stringent Response Activates Quorum Sensing and Modulates Cell Density-dependent Gene Expression in Pseudomonas Aeruginosa. J Bacteriol. 2001;183(18):5376-84. PubMed PMID: 11514523.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Stringent response activates quorum sensing and modulates cell density-dependent gene expression in Pseudomonas aeruginosa. AU - van Delden,C, AU - Comte,R, AU - Bally,A M, PY - 2001/8/22/pubmed PY - 2001/9/28/medline PY - 2001/8/22/entrez SP - 5376 EP - 84 JF - Journal of bacteriology JO - J. Bacteriol. VL - 183 IS - 18 N2 - During nutrient starvation, Escherichia coli elicits a stringent response involving the ribosome-associated protein RelA. Activation of RelA results in a global change in the cellular metabolism including enhanced expression of the stationary-phase sigma factor RpoS. In the human pathogen Pseudomonas aeruginosa, a complex quorum-sensing circuitry, linked to RpoS expression, is required for cell density-dependent production of many secreted virulence factors, including LasB elastase. Quorum sensing relies on the activation of specific transcriptional regulators (LasR and RhlR) by their corresponding autoinducers (3-oxo-C(12)-homoserine lactone [HSL] and C(4)-HSL), which function as intercellular signals. We found that overexpression of relA activated the expression of rpoS in P. aeruginosa and led to premature, cell density-independent LasB elastase production. We therefore investigated the effects of the stringent response on quorum sensing. Both lasR and rhlR gene expression and autoinducer synthesis were prematurely activated during the stringent response induced by overexpression of relA. Premature expression of lasR and rhlR was also observed when relA was overexpressed in a PAO1 rpoS mutant. The stringent response induced by the amino acid analogue serine hydroxamate (SHX) also led to premature production of the 3-oxo-C(12)-HSL autoinducer. This response to SHX was absent in a PAO1 relA mutant. These findings suggest that the stringent response can activate the two quorum-sensing systems of P. aeruginosa independently of cell density. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/11514523/Stringent_response_activates_quorum_sensing_and_modulates_cell_density_dependent_gene_expression_in_Pseudomonas_aeruginosa_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=11514523 DB - PRIME DP - Unbound Medicine ER -