Specific growth rate and not cell density controls the general stress response in Escherichia coli

Ihssen, Julian; Egli, Thomas

doi:10.1099/mic.0.26849-0

Cited by 137 publications

(156 citation statements)

References 50 publications

Supporting

Mentioning

143

Contrasting

Order By: Relevance

“…Moreover, because of the production of RpoS (subunit of RNA polymerase, represents a major factor involved in starvation survival), E. coli is able to rapidly adapt to, and tolerate, diverse stress conditions (Lange and Hengge-Aronis, 1991). It was thus shown that high osmolarity (Muffler et al, 1996), extremes and fluctuations of temperature (Muffler et al, 1997), low pH (Bearson et al, 1996) and low growth rate (Ihssen and Egli, 2004) induce rpoS in E. coli cells. Supporting the importance of rpoS, an rpoS À E. coli mutant showed decreased survival (colony-forming unit counts) in stationary phase in seawater (Rozen and Belkin, 2001).…”

Section: E Coli Fate In Natural Habitatsmentioning

confidence: 99%

Survival of Escherichia coli in the environment: fundamental and public health aspects

et al. 2010

View full text Add to dashboard Cite

In this review, our current understanding of the species Escherichia coli and its persistence in the open environment is examined. E. coli consists of six different subgroups, which are separable by genomic analyses. Strains within each subgroup occupy various ecological niches, and can be broadly characterized by either commensalistic or different pathogenic behaviour. In relevant cases, genomic islands can be pinpointed that underpin the behaviour. Thus, genomic islands of, on the one hand, broad environmental significance, and, on the other hand, virulence, are highlighted in the context of E. coli survival in its niches. A focus is further placed on experimental studies on the survival of the different types of E. coli in soil, manure and water. Overall, the data suggest that E. coli can persist, for varying periods of time, in such terrestrial and aquatic habitats. In particular, the considerable persistence of the pathogenic E. coli O157:H7 is of importance, as its acid tolerance may be expected to confer a fitness asset in the more acidic environments. In this context, the extent to which E. coli interacts with its human/animal host and the organism's survivability in natural environments are compared. In addition, the effect of the diversity and community structure of the indigenous microbiota on the fate of invading E. coli populations in the open environment is discussed. Such a relationship is of importance to our knowledge of both public and environmental health.

show abstract

Section: E Coli Fate In Natural Habitatsmentioning

confidence: 99%

Survival of Escherichia coli in the environment: fundamental and public health aspects

et al. 2010

View full text Add to dashboard Cite

show abstract

“…rpoS mutations are common in many selection regimens (Zambrano et al, 1993;Finkel and Kolter, 1999;Notley-McRobb and Ferenci, 2000;Chen et al, 2004;Zinser and Kolter, 2004;Mandel and Silhavy, 2005;Maharjan et al, 2006). In Escherichia coli, as growth rate of the culture declines, the concentration of s 38 within the cell reaches 30% the level of s 70 (Jishage and Ishihama, 1995;Ihssen and Egli, 2004). At this point, s 38 becomes an effective competitor with s 70 for the core RNA polymerase and begins to drive various stress-response genes (Jishage and Ishihama, 1995).…”

Section: Discussionmentioning

confidence: 99%

Evolutionary loss of the rdar morphotype in Salmonella as a result of high mutation rates during laboratory passage

2008

View full text Add to dashboard Cite

Rapid evolution of microbes under laboratory conditions can lead to domestication of environmental or clinical strains. In this work, we show that domestication due to laboratory passage in rich medium is extremely rapid. Passaging of wild-type Salmonella in rich medium led to diversification of genotypes contributing to the loss of a spatial phenotype, called the rdar morphotype, within days. Gene expression analysis of the rdar regulatory network demonstrated that mutations were primarily within rpoS, indicating that the selection pressure for scavenging during stationary phase had the secondary effect of impairing this highly conserved phenotype. If stationary phase was omitted from the experiment, radiation of genotypes and loss of the rdar morphotype was also demonstrated, but due to mutations within the cellulose biosynthesis pathway and also in an unknown upstream regulator. Thus regardless of the selection pressure, rapid regulatory changes can be observed on laboratory timescales. The speed of accumulation of rpoS mutations during daily passaging could not be explained by measured fitness and mutation rates. A model of mutation accumulation suggests that to generate the observed accumulation of r 38 mutations, this locus must experience a mutation rate of approximately 10 À4 mutations/gene/generation. Sequencing and gene expression of population isolates indicated that there were a wide variety of r 38 phenotypes within each population. This suggests that the rpoS locus is highly mutable by an unknown pathway, and that these mutations accumulate rapidly under common laboratory conditions.

show abstract

“…Phylogenetic relationships among the strains were measured as the ANI of all pairwise comparisons as described previously (Goris et al, 2007) (Supplementary Table S1). A minimal growth medium as described in the study by Ihssen and Egli (2004) was used for all experiments. Bacterial stock cultures were streaked onto agar plates and incubated overnight.…”

Section: Methodsmentioning

confidence: 99%

Gene expression analysis of E. coli strains provides insights into the role of gene regulation in diversification

et al. 2014

View full text Add to dashboard Cite

Escherichia coli spans a genetic continuum from enteric strains to several phylogenetically distinct, atypical lineages that are rare in humans, but more common in extra-intestinal environments. To investigate the link between gene regulation, phylogeny and diversification in this species, we analyzed global gene expression profiles of four strains representing distinct evolutionary lineages, including a well-studied laboratory strain, a typical commensal (enteric) strain and two environmental strains. RNA-Seq was employed to compare the whole transcriptomes of strains grown under batch, chemostat and starvation conditions. Highly differentially expressed genes showed a significantly lower nucleotide sequence identity compared with other genes, indicating that gene regulation and coding sequence conservation are directly connected. Overall, distances between the strains based on gene expression profiles were largely dependent on the culture condition and did not reflect phylogenetic relatedness. Expression differences of commonly shared genes (all four strains) and E. coli core genes were consistently smaller between strains characterized by more similar primary habitats. For instance, environmental strains exhibited increased expression of stress defense genes under carbon-limited growth and entered a more pronounced survival-like phenotype during starvation compared with other strains, which stayed more alert for substrate scavenging and catabolism during no-growth conditions. Since those environmental strains show similar genetic distance to each other and to the other two strains, these findings cannot be simply attributed to genetic relatedness but suggest physiological adaptations. Our study provides new insights into ecologically relevant gene-expression and underscores the role of (differential) gene regulation for the diversification of the model bacterial species.

show abstract

Specific growth rate and not cell density controls the general stress response in Escherichia coli

Cited by 137 publications

References 50 publications

Survival of Escherichia coli in the environment: fundamental and public health aspects

Survival of Escherichia coli in the environment: fundamental and public health aspects

Evolutionary loss of the rdar morphotype in Salmonella as a result of high mutation rates during laboratory passage

Gene expression analysis of E. coli strains provides insights into the role of gene regulation in diversification

Contact Info

Product

Resources

About