f RpoS-dependent stress tolerance in Pseudomonas aeruginosa
- Authors: Frieda Jørgensen†, Marc Bally, Virginie Chapon-Herve, Gerard Michel, Andrée Lazdunski, Paul Williams, G. S. A. B. Stewart
- Author for correspondence: Frieda Jørgensen. Tel: +44 1392 412853. Fax: +44 1392 412835. e-mail: email@example.com
- Microbiology, April 1999 145: 835-844, doi: 10.1099/13500872-145-4-835
- Subject: Physiology And Growth
- Published Online:
Summary: Pseudomonas aeruginosa is able to persist during feast and famine in many different environments including soil, water, plants, animals and humans. The alternative sigma factor encoded by the rpoS gene is known to be important for survival under stressful conditions in several other bacterial species. To determine if the P. aeruginosa RpoS protein plays a similar role in stationary-phase-mediated resistance, an rpoS mutant was constructed and survival during exposure to hydrogen peroxide, high temperature, hyperosmolarity, low pH and ethanol was investigated. Disruption of the rpoS gene resulted in two- to threefold increase in the rate of kill of stationary-phase cells. The rpoS mutant also survived less well than the parental strain during the initial phas of carbon or phosphate-carbon starvation. However, after 25 d starvation the remaining population of culturable cells was not significantly different. Stationary-phase cells of the RpoS-negative strain were much more stress resistant than exponentially growing RpoS-positive cells, suggesting that factors other than the RpoS protein must be associated with stationary-phase stress tolerance in P. aeruginosa. Comparison of two-dimensional PAGE of the rpoS mutant and the parental strain showed four major modifications of protein patterns associated with the rpoS mutation.
Present address: PHLS Food Microbiology Research Unit, Church Lane, Heavitree, Exeter EX2 5AD, UK.
© Society for General Microbiology 1999 | Published by the Microbiology Society
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