Project description:Deletion of yedL was found to signifcantly decrease type three secretion in EHEC O157:H7. Transcriptional profiles of Escherichia coli O157: H7 and the isogenic yedL mutant were generated and compared.
Project description:Deletion of yhaO was found to signifcantly decrease type three secretion in EHEC O157:H7. Transcriptional profiles of Escherichia coli O157: H7 and the isogenic yhaO mutant were generated and compared.
Project description:Pathogenic biofilms have been associated with persistent infections due to their high resistance to antimicrobial agents. To identify non-toxic biofilm inhibitors for enterohemorrhagic Escherichia coli O157:H7, indole-3-acetaldehyde was used and reduced E. coli O157:H7 biofilm formation. Global transcriptome analyses revealed that indole-3-acetaldehyde most repressed two curli operons, csgBAC and csgDEFG, and induced tryptophanase (tnaAB) in E. coli O157:H7 biofilm cells. Electron microscopy showed that indole-3-acetaldehyde reduced curli production in E. coli O157:H7. Together, this study shows that Actinomycetales are an important resource of biofilm inhibitors as well as antibiotics.
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.
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.
Project description:Transcript abundance in Escherichia coli O157:H7 was determined in the presence or absence of pulsed expression of the small RNA, AsxR.
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.
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.
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
Project description:Escherichia coli O157:H7 can cause haemorrhagic colitis and haemolytic uremic syndrome (HUS) in humans. This pathogen has been implicated in large food-borne outbreaks all over the world. By investigating the implicated salted salmon roe, Makino et al. (2000) suggested that E. coli O157:H7 in the viable but nonculturable (VBNC) state should be the culprit of the outbreak in Japan. High pressure CO2 (HPCD), one of the non-thermal pasteurization techniques, is an effective means to inactivate microorganisms. But in the previous study, we have demonstrated for the first time that HPCD could induce E. coli O157:H7 into the VBNC state, which poses a potential health risk to HPCD-treated products. In order to explore the potential formation mechanisms of VBNC E. coli O157:H7 induced by HPCD, the high-throughput Illumina RNA-seq transcriptomic analysis was conducted for E. coli O157:H7 cells treated at 5 MPa and 25 ℃ for 40 min (VBNC cells) and exponential-phase cells (the control). Finally, 97 genes that differentially transcribed between VBNC state and the control were obtained, with 22 genes up-regulated and 75 genes down-regulated in VBNC cells. These differentially expressed genes were classified in a variety of functional categories, including central metabolic processes, gene replication and expression, cell division, general stress response, respiration, membrane biosynthesis and transport and pathogenicity. Based on these differentially expressed genes, we suggest putative formation mechanisms of VBNC cells induced by HPCD. The finding will provide theoretical foundation for restraining the VBNC state formation under HPCD processing.
