Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Transcription profiling of E. coli O157:H7 w/t LB-Glu 7 hr biofilm cells with various chemicals

ABSTRACT: E coli O157H7 (EHEC) wildtype 7 hour biofilm cells studied in LB glucose medium with and without chemicals - Epinephrine, Norepinephrine and Indole. Biofilm cells were cultured from glass wool. Experiment Overall Design: Strain: E coli O157H7 (EHEC) Experiment Overall Design: Medium: LB-Glucose Experiment Overall Design: Chemicals: Epinephrine, Norepinephrine and Indole Experiment Overall Design: Time: 7 hours Experiment Overall Design: Cell type: Biofilm cells grown on glass wool

ORGANISM(S): Escherichia coli

SUBMITTER: Tarun Bansal

PROVIDER: E-GEOD-5552 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Differential effects of epinephrine, norepinephrine, and indole on Escherichia coli O157:H7 chemotaxis, colonization, and gene expression.

Bansal Tarun T Englert Derek D Lee Jintae J Hegde Manjunath M Wood Thomas K TK Jayaraman Arul A

Infection and immunity 20070625 9

During infection in the gastrointestinal tract, enterohemorrhagic Escherichia coli (EHEC) O157:H7 is exposed to a wide range of signaling molecules, including the eukaryotic hormones epinephrine and norepinephrine, and bacterial signal molecules such as indole. Since these signaling molecules have been shown to be involved in the regulation of phenotypes such as motility and virulence that are crucial for EHEC infections, we hypothesized that these molecules also govern the initial recognition o ...[more]

PMID: 17591798

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Project description:The ability to respond to stress is at the core of an organismâs survival. The hormones epinephrine and norepinephrine play a central role in stress responses in mammals, which require the synchronized interaction of the whole neuroendocrine system. Bacteria also sense and respond to epinephrine and norepinephrine as a means to gauge the metabolic and immune state of the host. Mammalian adrenergic receptors are G-coupled protein receptors (GPCRs), bacteria, however, sense these hormones through histidine sensor kinases (HKs). HKs autophosphorylate in response to multiple signals and transfer this phosphate to response regulators (RRs). Two bacterial adrenergic receptors have been identified in EHEC, QseC and QseE, with QseE being downstream of QseC in this signaling cascade. We mapped the QseC signaling cascade in the deadly pathogen enterohemorrhagic E. coli (EHEC), which exploits this signaling system to promote disease. Through QseC, EHEC activates expression of metabolic, virulence and stress response genes, synchronizing the cell response to these stress hormones. Coordination of these responses is achieved by QseC phosphorylating three of the thirty two EHEC RRs. The QseB RR, which is QseCâs cognate RR, activates the flagella regulon which controls bacteria motility and chemotaxis. The QseF RR, which is phosphorylated by the QseE adrenergic sensor, coordinates expression of virulence genes involved in formation of lesions in the intestinal epithelia by EHEC, and the bacterial SOS stress response. The third RR, KdpE, controls potassium uptake, osmolarity response, and also the formation of lesions in the intestine. Adrenergic regulation of bacterial gene expression shares several parallels with mammalian adrenergic signaling having profound effects in the whole organism. Understanding adrenergic regulation of a bacterial cell is a powerful approach to study the underlying mechanisms of stress and cellular survival. Experiment Overall Design: Microarray comparisons reveal some trends with respect to signaling cascades. Comparative methods were used to identify networks.

Project description:The Escherichia coli quorum-sensing regulator, SdiA, belongs to the LuxR family of transcriptional regulators and is responsible for detecting signals from other bacteria. Previously we found that SdiA is necessary for E. coli to control its biofilm formation with indole just as SdiA is necessary for E. coli to alter its biofilm formation in the presence of N-acylhomoserine lactones (AHLs). Here we engineered SdiA by random mutagenesis to further control biofilm formation in the presence of indole and AHLs. After screening of 477?? mutants with indole and two AHLs (N-butyryl-DL-homoserine lactone, and N-(3-oxooctanoyl)-L-homoserine lactone, C6HSL), five SdiA variants were obtained that altered biofilm with and without signals of indole and AHLs. Two truncation variants (1E11 and 14C3) lacking the C-terminal DNA-binding domain of SdiA showed the reduction of biofilm formation by 5-fold and 10-fold in LB and LB glu, respectively. DNA microarrays show that the evolved SdiA (1E11) compared to wild-type SdiA influences indole synthesis genes, AI-2 uptake genes, acid-resistance genes, motility related genes, cold-shock protein genes, and several regulatory protein genes. Corroborating DNA microarrays, SdiA variants produced various amounts of indole which led to different survivals in low pH and influenced swimming motility and final cell density. Also, an AHL sensitive variant (2D10) 2-fold increased biofilm formation in the presence of C6HSL, while another variant (6B12) lowered biofilm formation in the presence of C6HSL. Hence, the results clearly showed that mutation of SdiA itself directly controls biofilm formation and SdiA variants could be further recognized by the inter-species signal AHLs. This is the first random protein engineering to control biofilm formation. Experiment Overall Design: For the microarray experiments, 10 g glass wool (Corning Glass Works, Corning, N.Y.) were used to form biofilms in 250 mL LB ( 1 mM IPTG + Cm30) in 1 L Erlenmeyer shake flasks which were inoculated with overnight cultures diluted that were 1:100. The cells were shaken at 250 rpm and 30C for 12 hours to form biofilms on the glass wool, and RNA was isolated from the the biofilm cells.

Dataset Information

Transcription profiling of E. coli O157:H7 w/t LB-Glu 7 hr biofilm cells with various chemicals

Publications

Differential effects of epinephrine, norepinephrine, and indole on Escherichia coli O157:H7 chemotaxis, colonization, and gene expression.

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