The role of ClpP, RpoS and CsrA in growth and filament formation of Salmonella enterica serovar Typhimurium at low temperature

Gitte Maegaard Knudsen, Maj-Britt Nielsen, Line Elnif Thomsen, Søren Aabo, Ivan Rychlik, John Elmerdahl Olsen

Research output: Contribution to journalJournal articleResearchpeer-review

210 Downloads (Pure)

Abstract

Background: Salmonellae are food-borne pathogens of great health and economic importance. To pose a threat to humans, Salmonellae normally have to cope with a series of stressful conditions in the food chain, including low temperature. In the current study, we evaluated the importance of the Clp proteolytic complex and the carbon starvation protein, CsrA, for the ability of Salmonella Typhimurium to grow at low temperature. Results: A clpP mutant was severely affected in growth and formed pin point colonies at 10 degrees C. Contrary to this, rpoS and clpP/rpoS mutants were only slightly affected. The clpP mutant formed cold resistant suppressor mutants at a frequency of 2.5 x 10(-3) and these were found not to express RpoS. Together these results indicated that the impaired growth of the clpP mutant was caused by high level of RpoS. Evaluation by microscopy of the clpP mutant revealed that it formed filamentous cells when grown at 10 degrees C, and this phenotype too, disappered when rpoS was mutated in parallel indicating a RpoS-dependency. A csrA (sup) mutant was also growth attenuated a low temperature. An rpoS/csrA (sup) double mutant was also growth attenuated, indicating that the phenotype of the csrA mutant was independent from RpoS. Conclusions: The cold sensitivity of clpP mutant was associated with increased levels of RpoS and probably caused by toxic levels of RpoS. Although a csrA mutant also accumulated high level of RpoS, growth impairment caused by lack of csrA was not related to RpoS levels in a similar way.
Original languageEnglish
Article number208
JournalB M C Microbiology
Volume14
Issue number1
Number of pages9
ISSN1471-2180
DOIs
Publication statusPublished - 2014

Keywords

  • MICROBIOLOGY
  • COLD-SHOCK RESPONSE
  • ESCHERICHIA-COLI
  • STAPHYLOCOCCUS-AUREUS
  • GLOBAL REGULATION
  • STRESS-RESPONSE
  • PROTEIN CSRA
  • CELL-SIZE
  • SMALL RNA
  • VIRULENCE
  • GENES
  • Salmonella
  • Cold adaptation
  • ClpP
  • RpoS
  • CsrA

Fingerprint

Dive into the research topics of 'The role of ClpP, RpoS and CsrA in growth and filament formation of Salmonella enterica serovar Typhimurium at low temperature'. Together they form a unique fingerprint.

Cite this