Project description:A genome reduced E. coli strain MDS42ΔgalK::Ptet-gfp-kan were applied for the comparative transcriptome analysis. Genome-wide transcriptional changes under high osmotic prresure, high temperature condition and starvation were evaluated.
Project description:Transcription profile of Escherichia coli cells in biofilms under static batch culture was compared to that of E. coli cells in planktonic cultures. Both E. coli biofilm and planktonic cultures were cultivated for 18 h in 10% Luria-Bertani broth at room temperature (20 degree Celsius). Biofilms were grown in static batch culture in petri dishes. Both planktonic culture and biofilms were homogenized and run through a separated protocol.
Project description:The heat shock response is critical for organisms to survive at a high temperature. Heterologous expression of eukaryotic molecular chaperons protects Escherichia coli against heat stress. Here we report that expression of the plant E3 ligase BnTR1 significantly increase the thermotolerance of Escherichia coli. Different from eukaryotic chaperones, BnTR1 post-transcriptionally regulates the heat shock factor σ32 though zinc fingers of the RING domain, which interacts with DnaK resulting in stabilizing σ32 and subsequently up-regulating heat shock proteins. Our findings indicate the expression of BnTR1 confers thermoprotective effects on E. coli cells, and it may provide useful clues to engineer thermophilic bacterial strains.
Project description:Transcription profiling of wild type E. coli MG1655, intestine-adapted E. coli MG1655star, and E. coli MG1655 flhD mutant grown on glucose, mannose, and mucus. We previously isolated a spontaneous mutant of E. coli K-12, strain MG1655, following passage through the streptomycin-treated mouse intestine, which has colonization traits superior to the wild-type parent strain (Leatham, et. al., 2005, Infect Immun 73:8039-49) The intestine-adapted strain (E. coli MG1655star) grew faster on several different carbon sources compared to the wild-type and was non-motile due to deletion of the flhD gene. To further characterize E. coli MG1655star, we used several high-throughput genomic approaches. Whole-genome pyrosequencing did not reveal any changes on its genome, aside from the deletion at the flhDC locus, that could explain the colonization advantage of E. coli MG1655star. Microarray analysis revealed modest, yet significant induction of catabolic gene systems across the genome in both E. coli MG1655star and the isogenic flhD mutant. Catabolome analysis with Biolog GN2 Microplates revealed an enhanced ability of both E. coli MG1655star and the isogenic flhD mutant to oxidize a wide variety of carbon sources. The results show that intestine-adapted E. coli MG1655star is more fit than the wild-type for intestinal colonization because loss of FlhD results in elevated expression of genes involved in carbon and energy metabolism, leading to more efficient carbon source utilization, which results in a higher population size in the intestine. Hence mutations that enhance metabolic efficiency confer a colonization advantage.
Project description:YbjN, an enterobacteria-specific protein, is a multicopy suppressor of ts9 temperature sensitivity in Escherichia coli. Microarray study revealed that the expression level of ybjN was inversely correlated with the expression of flagellar, fimbrial and acid resistance genes. Over-expression of ybjN significantly down-regulated genes involved in the citric acid cycle, glycolysis, the glyoxylate shunt, oxidative phosphorylation, and amino acid and nucleotide metabolism. On the other hand, over-expression of ybjN up-regulated toxin-antitoxin modules, the SOS responsive pathway, cold shock proteins and starvation-induced transporter genes. Our results collectively suggest that YbjN may play important roles in regulating bacterial multicellular behaviors, metabolism and survival under various stress conditions in Es. coli.
Project description:Escherichia coli, the common inhabitant of the mammalian intestine, exhibits considerable intraspecies genomic variation, which has been suggested to reflect adaptation to different ecological niches. Also, regulatory trade-offs, e.g., between catabolic versatility and stress protection, are thought to result in significant physiological differences between strains. For these reasons, the relevance of experimental observations made for “domesticated” E. coli strains with regard to the behaviour of this species in its natural environments is often questioned and frequently doubts are raised on the status of E. coli as a defined species. We therefore investigated the variability of important eco-physiological functions such as carbon substrate uptake and breakdown capabilities as well as stress defence mechanisms in the genomes of commensal and pathogenic E. coli strains. Furthermore, eco-physiological properties of environmental strains were compared to standard laboratory strain K-12 MG1655. Catabolic, stress protection, and carbon- and energy source transport operons showed a very low intraspecies variability in 57 commensal and pathogenic E. coli. Environmental isolates adapted to glucose-limited growth in a similar way as E. coli MG1655, namely by increasing their catabolic flexibility and by inducing high affinity substrate uptake systems. Our results indicate that the major eco-physiological properties are highly conserved in the natural population of E. coli. This questions the proposed dominant role of horizontal gene transfer for niche adaptation. Keywords: comparative genomic hybridisation
Project description:Expression profile of E. coli BW25113 grown under standard laboratory atmosphere with a fine particulate matter (PM2.5) concentration of 17 mg m-3, under urban polluted atmosphere with a PM2.5 of 230 mg m-3 or under diesel exhaust atmosphere with a PM2.5 of 613 mg m-3. Expression profile of the diesel exhaust atmosphere-adapted E. coli strain T56-1 grown under diesel exhaust atmosphere.
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.
Project description:Transcription profiling of wild type E. coli MG1655, intestine-adapted E. coli MG1655star, and E. coli MG1655 flhD mutant grown on glucose, mannose, and mucus. We previously isolated a spontaneous mutant of E. coli K-12, strain MG1655, following passage through the streptomycin-treated mouse intestine, which has colonization traits superior to the wild-type parent strain (Leatham, et. al., 2005, Infect Immun 73:8039-49) The intestine-adapted strain (E. coli MG1655star) grew faster on several different carbon sources compared to the wild-type and was non-motile due to deletion of the flhD gene. To further characterize E. coli MG1655star, we used several high-throughput genomic approaches. Whole-genome pyrosequencing did not reveal any changes on its genome, aside from the deletion at the flhDC locus, that could explain the colonization advantage of E. coli MG1655star. Microarray analysis revealed modest, yet significant induction of catabolic gene systems across the genome in both E. coli MG1655star and the isogenic flhD mutant. Catabolome analysis with Biolog GN2 Microplates revealed an enhanced ability of both E. coli MG1655star and the isogenic flhD mutant to oxidize a wide variety of carbon sources. The results show that intestine-adapted E. coli MG1655star is more fit than the wild-type for intestinal colonization because loss of FlhD results in elevated expression of genes involved in carbon and energy metabolism, leading to more efficient carbon source utilization, which results in a higher population size in the intestine. Hence mutations that enhance metabolic efficiency confer a colonization advantage. Three strains were profiled: E. coli MG1655 wildtype, E. coli flhD, and an intestine adapted strain, MG1655star, derived from the wildtype and isolated from feces after 15 days in the streptomycin treated mouse intestine, which proved to be a better colonizer than the wildtype, were grown on MOPS minimal medium containing 0.2% glucose or mannose, or mucus (10 mg/ml) and RNA was extracted from logarithmic phase cultures, and also from mucus grown cells in late log phase.
Project description:We adapted thermal proteome profiling (TPP) to study the thermostability of Escherichia coli proteins in vivo. We monitored the E. coli meltome and proteome at different growth phases, in a tolC knock-out mutant and after drug treatment.