Escherichia coli
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ABSTRACT:
PROVIDER: PRJNA152941 | ENA |
REPOSITORIES: ENA
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Project description:Cinnamaldehyde is a natural antimicrobial and has been found to be effective against many foodborne pathogens including Escherichia coli O157:H7. Although its antimicrobial effects have been well investigated, limited information is available on its effects at the molecular level. Sublethal treatment at 200 mg/l cinnamaldehyde inhibited growth of E. coli O157:H7 at 37oC and for ≤ 2 h caused cell elongation, but from 2 to 4 h growth resumed and cells reverted to normal length. To understand this transient behaviour, genome-wide transcriptional analysis of E. coli O157:H7 was performed at 2 and 4 h exposure to cinnamaldehyde. Drastically different gene expression profiles were obtained at 2 and 4 h. At 2 h exposure, cinnamaldehyde induced overexpression of many oxidative stress-related genes, reduced DNA replication, and synthesis of protein, O-antigen and fimbriae. At 4 h, many cinnamaldehyde-induced repressive effects on E. coli O157:H7 gene expressions were reversed and oxidatve stress genes were nolonger differentially expressed.
2012-09-08 | GSE40693 | GEO
Project description:The transcriptome of Escherichia coli K-12 has been widely studied over a variety of conditions for the past decade while such studies involving E. coli O157:H7, its pathogenic cousin, are just now being conducted. To better understand the impact of heat shock on E. coli O157:H7, global transcript levels of strain EDL933 cells shifted from 37°C to 50°C for 15 min were compared to cells left at 37°C using microarrays. Keywords: Stress Response
2009-04-01 | GSE11463 | GEO
Project description:Escherichia coli O157 presents a number of specific problems in terms of food safety and public health. It has been found that E. coli O157 is more resistant to a number of the stresses encountered during food production such as heat, pH and osmotic shock. This greater resistance is thought to contribute to the low infectious dose of E. coli O157 (<100 organisms). Moreover, E. coli O157 is associated with debilitating conditions such as haemorrhagic colitis and haemoytic uraemic syndrome, particularly in children and the elderly. We have been studying the stress responses of E. coli O157:H7 (Sakai) and comparing with a commensal strain of E. coli K-12, MG1655. We found that E. coli O157 (Sakai) is more sensitive to oxidative stress than MG1655. A microarray study of these strains treated with sub-lethal concentrations (0.5mg/ml) of menadione revealed big differences in their responses. In E. coli O157 (Sakai), 540 genes responded significantly to the treatment compared to 121 genes in MG1655. One surprising finding from the microarray data was the observation that many iron-transport genes were up-regulated in E. coli O157 (Sakai) whereas relatively few were induced in MG1655 despite the fact that the bacteria were grown in a medium containing ample iron. We speculated that the induction of iron transport genes in an iron-rich medium might have contributed to the enhanced killing of E. coli O157 (Sakai) through triggering of a Fenton reaction. We speculated that the difference in sensitivity to oxidative stress might be due to differences in the intracellular iron content of E. coli O157 and MG1655. We found that E. coli O157 contains ~50% more iron than MG1655 and believe that during oxidative stress, this iron is released by damaged proteins. The greater levels of free iron in E. coli O157 will trigger a greater Fenton reaction that can damage the ferric uptake regulator (Fur), resulting in unregulated iron transport. In MG1655, the lower iron content results in a smaller Fenton reaction, enabling the cellular protection systems to limit damage and protect Fur.
2015-02-22 | GSE36130 | GEO
Project description:Honey has been widely used against bacterial infection for centuries. Previous studies suggested that honeys in high concentrations inhibited bacterial growth due to the presence of anti-microbial compounds, such as methylglyoxal, hydrogen peroxide, and peptides. In this study, we found that three honeys (acacia, clover, and polyfloral) in a low concentration as below as 0.5% (v/v) significantly suppress virulence and biofilm formation in enterohemorrhagic E. coli O157:H7 affecting the growth of planktonic cells while these honeys do not harm commensal E. coli K-12 biofilm formation. Transcriptome analyses show that honeys (0.5%) markedly repress quorum sensing genes (e.g., AI-2 import and indole biosynthesis), virulence genes (e.g., LEE genes), and curli genes (csgBAC). We found that glucose and fructose in honeys are key compounds to reduce the biofilm formation of E. coli O157:H7 via suppressing curli production, but not that of E. coli K-12. Additionally, we observed the temperature-dependent response of honeys and glucose on commensal E. coli K-12 biofilm formation; honey and glucose increase E. coli K-12 biofilm formation at 37°C, while they decrease E. coli K-12 biofilm formation at 26°C. These results suggest that honey can be a practical tool for reducing virulence and colonization of the pathogenic E. coli O157:H7, while honeys do not harm commensal E. coli community in the human.
2012-03-31 | GSE28193 | GEO
Project description:Cinnamaldehyde is a natural antimicrobial and has been found to be effective against many foodborne pathogens including Escherichia coli O157:H7. Although its antimicrobial effects have been well investigated, limited information is available on its effects at the molecular level. Sublethal treatment at 200 mg/l cinnamaldehyde inhibited growth of E. coli O157:H7 at 37oC and for M-bM-^IM-$ 2 h caused cell elongation, but from 2 to 4 h growth resumed and cells reverted to normal length. To understand this transient behaviour, genome-wide transcriptional analysis of E. coli O157:H7 was performed at 2 and 4 h exposure to cinnamaldehyde. Drastically different gene expression profiles were obtained at 2 and 4 h. At 2 h exposure, cinnamaldehyde induced overexpression of many oxidative stress-related genes, reduced DNA replication, and synthesis of protein, O-antigen and fimbriae. At 4 h, many cinnamaldehyde-induced repressive effects on E. coli O157:H7 gene expressions were reversed and oxidatve stress genes were nolonger differentially expressed. Duplicate E. coli O157:H7 cultures with or without 200 mg/l cinnamaldehyde were incubated at 37M-BM-0C for M-bM-^IM-$ 4 h. Cinnamaldehyde-induced changes in gene expression profiles were compared at 2 and 4 h using Affymetrix Ginechip 2.0 microarrays.
2012-09-08 | E-GEOD-40693 | biostudies-arrayexpress
Project description:The transcriptome of Escherichia coli K-12 has been widely studied over a variety of conditions for the past decade while such studies involving E. coli O157:H7, its pathogenic cousin, are just now being conducted. To better understand the impact of an anaerobic environment on E. coli O157:H7, global transcript levels of strain EDL933 cells grown aerobically were compared to cells grown anaerobically using microarrays.
2010-12-01 | GSE13301 | GEO
Project description:The transcriptome of Escherichia coli K-12 has been widely studied over a variety of conditions for the past decade while such studies involving E. coli O157:H7, its pathogenic cousin, are just now being conducted. To better understand the impact of intracellular life within a ruminant and environmental protozoan on E. coli O157:H7, global transcript levels of strain EDL933 cells inside Acanthamoeba were compared to cell grown in the protozoan media (ATCC PYG712) by microarray.
2010-12-01 | GSE16762 | GEO
Project description:Pathogenic biofilms have been associated with persistent infections due to high resistance to antimicrobial agents while commensal biofilms often fortify host immune system. Hence, controlling biofilm formation of both pathogenic bacteria and commensal bacteria is important in bacteria-related diseases. We investigated the effect of plant flavonoids on biofilm formation of both enterohemorrhagic Escherichia coli O157:H7 and three commensal E. coli K-12 strains. Phloretin abundant in apples markedly reduced E. coli O157:H7 biofilm formation without affecting the growth of planktonic cells while phloretin did not harm commensal E. coli K-12 biofilms. Also, phloretin reduced E. coli O157:H7 attachment to human colon epithelial cells. Global transcriptome analyses revealed that phloretin repressed toxin genes (hlyE and stx2), autoinducer-2 importer genes (lsrACDBF), a curli gene (csgA), and a dozens of prophage genes in E. coli O157:H7 cells. Electron microscopy confirmed that phroretin reduced the curli production in E. coli O157:H7. In addition, phloretin suppressed TNF-α-induced inflammatory response in vitro using human colonic epithelial cells. Moreover, in the trinitrobenzene sulfonic acid (TNBS)-induced rat colitis model, phloretin significantly ameliorated colon inflammation and body weight loss. Taken together, our results suggest that phloretin may act as an inhibitor of E. coli O157:H7 biofilm formation as well as anti-inflammatory agent on inflammatory bowel diseases while leaving beneficial commensal E. coli biofilm intact.
2011-11-22 | GSE28144 | GEO
Project description:The transcriptome of Escherichia coli K-12 has been widely studied over a variety of conditions for the past decade while such studies involving E. coli O157:H7, its pathogenic cousin, are just now being conducted. To better understand the impact of rumen fluid on E. coli O157:H7, global transcript levels of strain EDL933 cells resuspended in heat clarified rumen fluid for 15 min were compared to cells resuspended in fresh LB using microarrays.
2010-12-01 | GSE16747 | GEO
Project description:Escherichia coli O157 presents a number of specific problems in terms of food safety and public health. It has been found that E. coli O157 is more resistant to a number of the stresses encountered during food production such as heat, pH and osmotic shock. This greater resistance is thought to contribute to the low infectious dose of E. coli O157 (<100 organisms). Moreover, E. coli O157 is associated with debilitating conditions such as haemorrhagic colitis and haemoytic uraemic syndrome, particularly in children and the elderly. We have been studying the stress responses of E. coli O157:H7 (Sakai) and comparing with a commensal strain of E. coli K-12, MG1655. We found that E. coli O157 (Sakai) is more sensitive to oxidative stress than MG1655. A microarray study of these strains treated with sub-lethal concentrations (0.5mg/ml) of menadione revealed big differences in their responses. In E. coli O157 (Sakai), 540 genes responded significantly to the treatment compared to 121 genes in MG1655. One surprising finding from the microarray data was the observation that many iron-transport genes were up-regulated in E. coli O157 (Sakai) whereas relatively few were induced in MG1655 despite the fact that the bacteria were grown in a medium containing ample iron. We speculated that the induction of iron transport genes in an iron-rich medium might have contributed to the enhanced killing of E. coli O157 (Sakai) through triggering of a Fenton reaction. We speculated that the difference in sensitivity to oxidative stress might be due to differences in the intracellular iron content of E. coli O157 and MG1655. We found that E. coli O157 contains ~50% more iron than MG1655 and believe that during oxidative stress, this iron is released by damaged proteins. The greater levels of free iron in E. coli O157 will trigger a greater Fenton reaction that can damage the ferric uptake regulator (Fur), resulting in unregulated iron transport. In MG1655, the lower iron content results in a smaller Fenton reaction, enabling the cellular protection systems to limit damage and protect Fur. Overnight cultures of E. coli O157 (Sakai) and E. coli K-12 MG1655 were grown in Neidhardt's EZ Rich Defined Medium and diluted 1:100 in 50 ml fresh medium in 125 ml Ehrlenmeyer flasks. The cultures were shaken at 37C until the optical density (OD600) reached 0.4. Each culture was divided into 2 equal parts in identical flasks. One flask contained menadione bisulphite to a final concentration of 0.5 mg/ml; the other flask contained an equivalent volume of distilled water. The flasks were shaken for a further 10 mins and then treated with RNAprotect™ to stabilise the mRNA. The experiment was performed 3 times on different days. Six custom-made microarray slides were used in this study; each slide was hybridised with labelled cDNA made from mRNA taken from untreated and treated E. coli O157 (Sakai) or MG1655.
2015-02-22 | E-GEOD-36130 | biostudies-arrayexpress