Survival of Escherichia coli during long-term starvation: effects of aeration, NaCl, and the rpoS and osmC gene products - PubMed (original) (raw)

Survival of Escherichia coli during long-term starvation: effects of aeration, NaCl, and the rpoS and osmC gene products

A Conter et al. Res Microbiol. 2001 Jan-Feb.

Free article

Abstract

The survival of Escherichia coli was investigated during long-term starvation in rich media. In aerated cultures, E. coli lost the ability to form colonies earlier in NaCl-free Luria broth than in LB medium containing NaCl. Improved survival at low aeration and the sensitivity to hydrogen peroxide in aging cultures indicated a major role for oxidative stress in cell mortality. Mutants in rpoS, lacking the sigmaS subunit of RNA polymerase, showed altered survival in salt-containing media. However, in the absence of NaCl, although these mutants exhibited a massive loss of viability during the first 2 days, this was followed by a stabilization of the number of survivors. The starved culture contained survivors until at least day 9, long after a wild-type strain had completely lost viability. This peculiar behavior suggests that, in rich media of low osmotic pressure, sigmaS helps in short-term survival but hampers long-term survival. Mutants in osmC, a member of the rpoS regulon, also exhibited reduced survival and increased sensitivity to oxidative stress. The biochemical function of the envelope protein OsmC remains unknown, but present data indicated that it participates, directly or indirectly, in the defense against oxidative compounds.

PubMed Disclaimer

Similar articles

Cited by

Publication types

MeSH terms

Substances

LinkOut - more resources