Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Response of Rhodopirellula baltica to heat shock

ABSTRACT: Expression profiling of the stress response of the marine Planctomycete Rhodopirellula baltica after a temperature up-shift. R. baltica cultures were grown at 28°C and then shifted to 37°C. Samples were taken after 10, 20, 40, 60 and 300min and compared with cultures before the up-shift (28°C). Time series experiment, whole genome array 5 time points, 3 replicates per time point. Each time point sample was compared with the reference. 3 self-self reference hybridizations. In total, 18 samples.

ORGANISM(S): Rhodopirellula baltica

SUBMITTER: Patricia Wecker

PROVIDER: E-GEOD-13769 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Transcriptional response of the model planctomycete Rhodopirellula baltica SH1(T) to changing environmental conditions.

Wecker Patricia P Klockow Christine C Ellrott Andreas A Quast Christian C Langhammer Philipp P Harder Jens J Glöckner Frank Oliver FO

BMC genomics 20090902

<h4>Background</h4>The marine model organism Rhodopirellula baltica SH1(T) was the first Planctomycete to have its genome completely sequenced. The genome analysis predicted a complex lifestyle and a variety of genetic opportunities to adapt to the marine environment. Its adaptation to environmental stressors was studied by transcriptional profiling using a whole genome microarray.<h4>Results</h4>Stress responses to salinity and temperature shifts were monitored in time series experiments. Chemo ...[more]

PMID: 19725962

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Project description:While significant advances have been made in EHEC pathogenesis, we still do not fully understand the impact of environmental stress on EHEC virulence. During the course of infection, EHEC must evade or overcome several biological barriers, the first of which is the gastric acidity encountered during passage through the stomach. EHEC is remarkable in its ability to tolerate this acidity. There are four different acid resistance systems that provide E. coli O157:H7 protection against exposure to low pH (2-2.5). Interestingly, EHEC uses these acid resistance systems differentially for survival in foods versus the bovine intestinal tract. The glutamate-dependent acid-resistance system is thought to offer the best protection below pH 3. Since the infectious dose of EHEC is so low (50-100 organisms), acid resistance becomes an important virulence trait. Studies of EHEC response to acid stress have focused primarily on levels of acid tolerance and the molecular basis of tolerance. However, the impact of acid stress on EHEC virulence is less well understood. In the related pathogen, EPEC, the plasmid-encoded regulator, Per, that regulates expression of many EPEC virulence factors, is regulated negatively at pH 5.5 and positively at pH 8.0, suggesting that virulence gene expression is repressed during mild acid stress and enhanced in alkaline pH typical of the small intestine. Expression of EPEC type III secreted factors involved in A/E lesion formation has been shown to be influenced by factors including culture media, iron and calcium levels. Protein secretion was inhibited at pH 6 and 8. In a third study, a gadE (encoding acid resistance regulator) mutation resulted in increased adhesion of E.coli O157:H7 to colonic epithelial cells, suggesting negative regulation of one or more adhesins. Other studies have reported that shiga toxin production is sensitive to culture conditions including pH. However, there are no studies of EHEC virulence changes after more severe acid stress nor studies linking stressed EHEC virulence phenotype with transcriptional changes. The goal of this study was to determine how acid stress affects EHEC virulence properties and through microarray analysis, define the genetic basis for these changes. Understanding how acid stress modulates the virulence potential of this pathogen is essential for delineating the pathogenesis of disease caused by EHEC infection and may offer novel approaches to prevent and treat EHEC infections. Bacteria were grown in LB broth overnight, then subcultured into DMEM and grown at 37C, 5%Co2. Bacteria were then subjected to one of three acid stress protocols: 1) UA30: growth in DMEM pH 7.4 followed by growth in DMEM pH 3.0 for 30 minutes; 2) AA30: growth in DMEM pH 5.0 (adaptation) followed by growth in DMEM pH 3.0; 3) UA15: growth in DMEM pH 7.4 followed by growth in DMEM pH 3.0 for 15 minutes. DMEM was supplemented with 25 mM MES (pH 5.0) and in the case of the control (unadapted, unshocked) 25 mM MOPS (pH 7.4) and the adaptation step was again carried out at 37C and 5% CO2. Acid shocking was done at pH 3.0 (unbuffered) at room temperature for all treatments

Dataset Information

Response of Rhodopirellula baltica to heat shock

Publications

Transcriptional response of the model planctomycete Rhodopirellula baltica SH1(T) to changing environmental conditions.

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