The Alternative Sigma Factor, ςE, Is Critically Important for the Virulence of Salmonella typhimurium

Humphreys, Sue; Stevenson, Andrew; Bacon, Andrew; Weinhardt, A. Barbara; Roberts, Mark

doi:10.1128/.67.4.1560-1568.1999

Cited by 32 publications

(42 citation statements)

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“…These included the anti-sigma factor encoding genes rseE and rseA , which are involved in sigma E activation in response to envelope and acid stress, and involved in virulence in S . Typhimurium [40] , [41] . Other virulence related genes of type B where the ESP TSS was absent and the LSP TSS was in a different position included lrp, pipD (SPI5), pagC, ygdP and rfaH.…”

Section: Resultsmentioning

confidence: 99%

The Primary Transcriptome of Salmonella enterica Serovar Typhimurium and Its Dependence on ppGpp during Late Stationary Phase

2014

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We have used differential RNA-seq (dRNA-seq) to characterise the transcriptomic architecture of S. Typhimurium SL1344, and its dependence on the bacterial alarmone, guanosine tetraphosphate (ppGpp) during late stationary phase, (LSP). Under LSP conditions we were able to identify the transcriptional start sites (TSSs) for 53% of the S. Typhimurium open reading frames (ORFs) and discovered 282 candidate non-coding RNAs (ncRNAs). The mapping of LSP TSSs enabled a detailed comparison with a previous dRNA-seq study of the early stationary phase (ESP) transcriptional architecture of S. Typhimurium SL1344 and its dependence on ppGpp. For the purposes of this study, LSP was defined as an aerobic LB culture grown to a later optical density reading (OD600 = 3.6) compared to ESP (OD600 = 2.3). The precise nucleotide positions of the majority of S. Typhimurium TSSs at LSP agreed closely with those identified at ESP. However, the identification of TSSs at different positions, or where additional or fewer TSSs were found at LSP compared to ESP enabled the genome-wide categorisation of growth phase dependent changes in promoter structure, the first time such an analysis has been done on this scale. Comparison of the ppGpp-dependency LSP and ESP TSSs for mRNAs and ncRNAs revealed a similar breadth of ppGpp-activation and repression. However, we note several ncRNAs previously shown to be involved in virulence were highly ppGpp-dependent at LSP. Finally, although SPI1 was expressed at ESP, we found SPI1 was not as highly expressed at LSP, instead we observed elevated expression of SPI2 encoded genes. We therefore also report an analysis of SPI2 transcriptional architecture at LSP resulting in localisation of SsrB binding sites and identification of a previously unreported SPI2 TSS. We also show that ppGpp is required for nearly all of SPI2 expression at LSP as well as for expression of SPI1 at ESP.

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Section: Resultsmentioning

confidence: 99%

The Primary Transcriptome of Salmonella enterica Serovar Typhimurium and Its Dependence on ppGpp during Late Stationary Phase

2014

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“…Interestingly htrA occurs in a predicted operon upstream of rpoD . In Salmonella enterica serovar Typhimurium [ 66 , 67 ] and Yersinia enterocolitica [ 68 , 69 ] an alternative sigma factor RpoE has been implicated in the regulation of htrA and resistance to oxidative stress. Taken together, these results suggest that perhaps HtrA in concert with RpoD may be part of a stress response that is activated during P. gingvalis biofilm growth.…”

Section: Resultsmentioning

confidence: 99%

Comparative transcriptomic analysis of Porphyromonas gingivalisbiofilm and planktonic cells

Seers

Boyce

et al. 2009

BMC Microbiol

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BackgroundPorphyromonas gingivalis in subgingival dental plaque, as part of a mature biofilm, has been strongly implicated in the onset and progression of chronic periodontitis. In this study using DNA microarray we compared the global gene expression of a P. gingivalis biofilm with that of its planktonic counterpart grown in the same continuous culture.ResultsApproximately 18% (377 genes, at 1.5 fold or more, P-value < 0.01) of the P. gingivalis genome was differentially expressed when the bacterium was grown as a biofilm. Genes that were down-regulated in biofilm cells, relative to planktonic cells, included those involved in cell envelope biogenesis, DNA replication, energy production and biosynthesis of cofactors, prosthetic groups and carriers. A number of genes encoding transport and binding proteins were up-regulated in P. gingivalis biofilm cells. Several genes predicted to encode proteins involved in signal transduction and transcriptional regulation were differentially regulated and may be important in the regulation of biofilm growth.ConclusionThis study analyzing global gene expression provides insight into the adaptive response of P. gingivalis to biofilm growth, in particular showing a down regulation of genes involved in growth and metabolic activity.

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“…A loss of rpoE gene activity has also been shown to cause a defect in cell viability of E. coli and increase cell envelope stress ( 50 , 118 , 122 , 134 ). In Salmonella, rpoE mutants were found to be less responsive to heat shock temperatures, exhibiting an intracellular defect in the survivability within a macrophage and becoming avirulent in a mouse infection model ( 126 , 135 – 137 ). In addition, the rpoE gene has been shown to be essential in response to starvation stress ( 138 ), oxidative stress ( 92 ), antimicrobial peptide resistance ( 139 ), and osmotic and cold stresses ( 127 ).…”

Section: Heat Shock and Virulencementioning

confidence: 99%

The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review

et al. 2017

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In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection.

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The Alternative Sigma Factor, ςE, Is Critically Important for the Virulence of Salmonella typhimurium

Cited by 32 publications

References 0 publications

The Primary Transcriptome of Salmonella enterica Serovar Typhimurium and Its Dependence on ppGpp during Late Stationary Phase

The Primary Transcriptome of Salmonella enterica Serovar Typhimurium and Its Dependence on ppGpp during Late Stationary Phase

Comparative transcriptomic analysis of Porphyromonas gingivalisbiofilm and planktonic cells

The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review

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