E coli O157:H7 w/t LB-Glu 7 hr biofilm cells with various chemicals
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ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE5552 | GEO | 2007/07/09
SECONDARY ACCESSION(S): PRJNA96049
REPOSITORIES: GEO
Similar Datasets
Project description: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
2008-06-13 | E-GEOD-5552 | biostudies-arrayexpress
Project description:Contamination with enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem but there is no effective therapy available for EHEC infection. Biofilm formation is closely related with EHEC infection and is one of the mechanisms of antimicrobial resistance. Antibiofilm screening of 560 plant secondary metabolites against EHEC shows that ginkgolic acids C15:1 and C17:1 at 5 μg/ml and Ginko biloba extract at 100 μg/ml significantly inhibited EHEC biofilm formation on the surface of polystyrene, nylon membrane, and glass. Importantly, the working concentration of ginkgolic acids and G. biloba extract did not affect bacterial growth and has been known to be non-toxic to human. Transcriptional analyses showed that ginkgolic acid C15:1 repressed curli genes and prophage genes in EHEC, which were corroborated by reduced fimbriae production and biofilm reduction in EHEC. Interestingly, ginkgolic acids and G. biloba extract did not inhibit the biofilm formation of commensal E. coli K-12 strain. The current study suggests that plant secondary metabolites are important resource of biofilm inhibitors, as well as other bioactive compounds.
2015-07-29 | GSE49367 | GEO
Project description:E. coli K-12 BW25113 mutant strain ycfR expression in biofilm cells relative to E. coli wild-type strain expression in biofilm cells. All samples cultured in LB glu with glass wool Keywords: Cell type comparison
2006-09-26 | GSE5904 | GEO
Project description:Two lineages of enterohemorrhagic (EHEC) Escherichia coli O157:H7 (EDL933, Stx1+ and Stx2+) and 86-24 (Stx2+) were investigated in regards to biofilm formation on an abiotic surface. Strikingly, EDL933 strain formed a robust biofilm while 86-24 strain formed no biofilm on either a polystyrene plate or a polyethylene tube. To identify the genetic mechanisms of different biofilm formation in two EHEC strains, DNA microarrays were first performed and phenotypic assays were followed. In the comparison of the EDL933 strain versus 86-24 strain, genes (csgBAC and csgDEFG) involved in curli biosynthesis were significantly induced while genes (trpLEDCB and mtr) involved in indole signaling were repressed. Additionally, a dozen of phage genes were differentially present between two strains. Curli assays using a Congo red plate and scanning electron microscopy corroborate the microarray data as the EDL 933 strain produces a large amount of curli, while 86-24 forms much less curli. Also, the indole production in the EDL933 was 2-times lower than that of 86-24. It was known that curli formation positively regulates and indole negatively regulates biofilm formation of EHEC. Hence, it appears that less curli formation and high indole production in the 86-24 strain are majorly responsible for no biofilm formation.
2011-01-19 | GSE19953 | GEO
Project description:E. coli K-12 BW25113 mutant strain ycfR expression in biofilm cells relative to E. coli wild-type strain expression in biofilm cells. All samples cultured in LB glu with glass wool Experiment Overall Design: Strains: E. coli K-12 BW25113 wild type and mutant ycfR Experiment Overall Design: Medium: LB glu Experiment Overall Design: Biofilm grown on glass wool Experiment Overall Design: Time: 15 hr Experiment Overall Design: Cell type: biofilm
2008-06-14 | E-GEOD-5904 | biostudies-arrayexpress
Project description:Contamination with enterohemorrhagic Escherichia coli O157:H7 (EHEC) is a worldwide problem but there is no effective therapy available for EHEC infection. Biofilm formation is closely related with EHEC infection and is one of the mechanisms of antimicrobial resistance. Antibiofilm screening of 560 plant secondary metabolites against EHEC shows that ginkgolic acids C15:1 and C17:1 at 5 μg/ml and Ginko biloba extract at 100 μg/ml significantly inhibited EHEC biofilm formation on the surface of polystyrene, nylon membrane, and glass. Importantly, the working concentration of ginkgolic acids and G. biloba extract did not affect bacterial growth and has been known to be non-toxic to human. Transcriptional analyses showed that ginkgolic acid C15:1 repressed curli genes and prophage genes in EHEC, which were corroborated by reduced fimbriae production and biofilm reduction in EHEC. Interestingly, ginkgolic acids and G. biloba extract did not inhibit the biofilm formation of commensal E. coli K-12 strain. The current study suggests that plant secondary metabolites are important resource of biofilm inhibitors, as well as other bioactive compounds. E. coli GeneChip Genome 2.0 Array (Affymetrix, P/N 900551, Santa Clara, USA) was used to study the differential gene expression of the E. coli O157:H7 cells after the treatment with ginkgolic acid C15:1 (0.005 mg/ml). Cells were inoculated into 25 ml LB medium in 250 mL shake flasks with a starting OD600 of 0.05, and cultured at 37oC for 8 h without shaking in the presence or absence of ginkgolic acid C15:1 (5 μg/ml). To prevent RNA degradation, RNase inhibitor (RNAlater, Ambion, TX, USA) was added, and the EHEC cells were collected by centrifugation at 10,000 rpm for 1 min. The cell pellets obtained were immediately frozen with dry ice and stored at -80°C. Total RNA was isolated using a Qiagen RNeasy mini Kit (Valencia, CA, USA).
2015-07-29 | E-GEOD-49367 | biostudies-arrayexpress
Project description:Two lineages of enterohemorrhagic (EHEC) Escherichia coli O157:H7 (EDL933, Stx1+ and Stx2+) and 86-24 (Stx2+) were investigated in regards to biofilm formation on an abiotic surface. Strikingly, EDL933 strain formed a robust biofilm while 86-24 strain formed no biofilm on either a polystyrene plate or a polyethylene tube. To identify the genetic mechanisms of different biofilm formation in two EHEC strains, DNA microarrays were first performed and phenotypic assays were followed. In the comparison of the EDL933 strain versus 86-24 strain, genes (csgBAC and csgDEFG) involved in curli biosynthesis were significantly induced while genes (trpLEDCB and mtr) involved in indole signaling were repressed. Additionally, a dozen of phage genes were differentially present between two strains. Curli assays using a Congo red plate and scanning electron microscopy corroborate the microarray data as the EDL 933 strain produces a large amount of curli, while 86-24 forms much less curli. Also, the indole production in the EDL933 was 2-times lower than that of 86-24. It was known that curli formation positively regulates and indole negatively regulates biofilm formation of EHEC. Hence, it appears that less curli formation and high indole production in the 86-24 strain are majorly responsible for no biofilm formation. For the microarray experiments, E. coli O157:H7 EDL933 and 86-24 were inoculated in 25 ml of LB in 250 ml shake flasks with overnight cultures that were diluted 1:100. Cells were shaken at 250 rpm and 37°C for an absorbance of 4.0 at 600 nm. Cells were immediately chilled with dry ice and 95% ethanol (to prevent RNA degradation) for 30 sec before centrifugation in 50 ml centrifuge tubes at 13,000 g for 2 min; cell pellets were frozen immediately with dry ice and stored -80°C. RNA was isolated using Qiagen RNeasy mini Kit (Valencia, CA, USA). RNA quality was assessed by Agilent 2100 bioanalyser using the RNA 6000 Nano Chip (Agilent Technologies, Amstelveen, The Netherlands), and quantity was determined by ND-1000 Spectrophotometer (NanoDrop Technologies, Inc., DE, USA).
2011-01-19 | E-GEOD-19953 | biostudies-arrayexpress
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.
2009-06-26 | GSE14069 | GEO
Project description:For the microarray experiments, 10 g glass wool (Corning Glass Works, Corning, N.Y.) were used to form biofilms (30) in 250 mL in 1 L Erlenmeyer shake flasks which were inoculated with overnight cultures diluted that were 1:100. For EHEC with 7-hydroxyindole and isatin, 1000 mM 7-hydroxyindole in 250 mL DMF, 250 mM isatin in 250 mL DMF, or 250 mL DMF alone were added to cells grown in LB. The cells were shaken at 250 rpm and 30°C for 7 hours to form biofilms on the glass wool, and RNA was isolated from the suspension cells and the biofilm. Experiment Overall Design: Strain: EHEC EDL933 (ATCC 43895) wild type Experiment Overall Design: Medium: LB Experiment Overall Design: Cells: Suspension cells and biofilm cells on glass wool Experiment Overall Design: Time: 7h
2008-06-14 | E-GEOD-6195 | biostudies-arrayexpress
Project description:Enterohemorrhagic Escherichia coli (EHEC), including serotype O157:H7, cause severe food-borne illness. On route to the human colon, they encounter and resist, numerous anti-microbial ingestion stresses. We hypothesize that these stresses cue EHEC to alter virulence properties. This study investigated the impact of bile salts on virulence properties and examined the genetic basis of the phenotypes. Established assays were used to examine adhesion to human epithelial cells, motility, verotoxin (VT) production and antimicrobial resistance with/without bile salt stress. Bacteria treated for 90 minute in DMEM plus 0.15% (w/v) bile salt mix demonstrated significantly enhanced adhesion to epithelial cells and resistance to several antibiotics but did not increase motility or VT production. To determine the genetic basis of these phenotypes a microarray experiment was conducted. EHEC strain 86-24, in mid-log phase of growth, were grown in DMEM pH 7.4 (control), or DMEM plus bile salt mix (0.15% w/v), for 90 minutes, statically at 37˚C, 5% CO2 prior to harvesting RNA for the microarray study. Four biological replicates were produced for each treatment. Microarray and gene expression analysis (semi-quantitative RT-PCR and beta-galactosidase reporter assays) of bile salt-treated EHEC revealed significant up-regulation of genes for lipid A modification, fimbriae, an efflux pump, and a two-component regulatory system relative to the bacteria grown in DMEM alone. This work points to several mechanisms that EHEC employs to resist the stresses of the human small intestine, notably efflux, antimicrobial resistance, and outer membrane alterations. Bile salts enhanced the virulence-related properties of increased adhesion and resistance to antimicrobials but not VT production or motility. This research contributes to our understanding of how EHEC senses and responds to host environmental signals and the mechanisms this pathogen uses to successfully colonize and infect the human host.
2011-09-06 | GSE22060 | GEO