Project description:Escherichia coli laboratory strains remain instrumental to the discovery and development of biomarkers as drugs and diagnostic analytes in the post genomic era. The transcriptional regulator SlyA is a member of the multiple antibiotic resistance regulator family of transcription factors, which is associated with bacterial responses to host-derived oxidative stress, antibiotics resistance and virulence, and homologues exist in other Enterobacteriaceae. Here, we announce a transcriptome RNA sequencing data set detailing global gene expression in the wild type E. coli BW25113 and the slyA mutant. Results reveal heterogeneous functionality of SlyA that may vary between pathovars of E. coli. but which require further annotations of differentially expressed tRNAs
Project description:Acetylation of lysine residues is conserved in all three kingdoms; however, its role in prokaryotes is unknown. Here we demonstrate that acetylation enables the reference bacterium Escherichia coli to withstand environmental stress. Specifically, the bacterium reaches higher cell densities and becomes more resistant to heat and oxidative stress when its proteins are acetylated, as shown by deletion of the gene encoding acetyltransferase YfiQ and the gene encoding deacetylase CobB, as well as by overproducing YfiQ and CobB. Furthermore, we show that the increase in oxidative stress resistance with acetylation is due to the induction of catalase activity through enhanced katG expression. We also found that two-component system proteins CpxA, PhoP, UvrY, and BasR are associated with cell catalase activity and may be responsible as the connection between bacterial acetylation and the stress response. This is the first demonstration of a specific environmental role of acetylation in prokaryotes.
Project description:Glycerol is an attractive feedstock for biofuels since it accumulates as a byproduct during biodiesel operations; hence, it is interesting to consider converting glycerol to hydrogen using the formate hydrogen lyase system of Escherichia coli which converts pyruvate to hydrogen. Starting with Escherichia coli BW25113 frdC that lacks fumarate reductase to eliminate the negative effect of accumulated hydrogen on glycerol fermentation and by using both adaptive evolution and chemical mutagenesis combined with a selection method based on increased growth on glycerol, we obtained an improved strain, HW2, that produces 20-fold more hydrogen in glycerol medium (0.68 mmol/L/h) compared to that of frdC mutant. HW2 also grows 5-fold faster (0.25 1/h) than BW25113 frdC on glycerol, so it achieves a reasonable growth rate. Corroborating the increase in hydrogen production, glycerol dehydrogenase activity in HW2 increased 4-fold compared to BW25113 frdC. In addition, a whole-transcriptome study revealed that several pathways that would decrease hydrogen yields were repressed in HW2 (fbp, focA, and gatYZ) while a beneficial pathway, eno which encodes enolase was induced.
Project description:RpoS, an alternative sigma factor, is critical for stress response in Escherichia coli.RpoS also acts as a global regulator for stress control of gene expression, and actually dose so in log stage and stationary stage. To further understand the effect of environmental stresses on in ethanologenic strains, DNA microarrys was used to analyze the expression profiles of E. coli and its rpoS mutant strain.
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:The purpose of this study is to determine whether the presence of pathogenic Escherichia coli in colon is associated with psychiatric disorders.
Project description:The present study investigated the role(s) of RNase I (encoded by the rna gene) in Escherichia coli by comparative gene expression analysis of an rna mutant and the isogenic wild-type E. coli strain BW25113. The transcriptomic analysis aims to provide mechanistic insight into aberrant phenotypes observed in the RNase I-deficient mutant.
Project description:Despite the characterization of many aetiologic genetic changes. The specific causative factors in the development of sporadic colorectal cancer remain unclear. This study was performed to detect the possible role of Enteropathogenic Escherichia coli (EPEC) in developing colorectal carcinoma.
Project description:Acetylation of lysine residues is conserved in all three kingdoms; however, its role in prokaryotes is unknown. Here we demonstrate that acetylation enables the reference bacterium Escherichia coli to withstand environmental stress. Specifically, the bacterium reaches higher cell densities and becomes more resistant to heat and oxidative stress when its proteins are acetylated, as shown by deletion of the gene encoding acetyltransferase YfiQ and the gene encoding deacetylase CobB, as well as by overproducing YfiQ and CobB. Furthermore, we show that the increase in oxidative stress resistance with acetylation is due to the induction of catalase activity through enhanced katG expression. We also found that two-component system proteins CpxA, PhoP, UvrY, and BasR are associated with cell catalase activity and may be responsible as the connection between bacterial acetylation and the stress response. This is the first demonstration of a specific environmental role of acetylation in prokaryotes. Overnight cultures of cobB/pCA24N-cobB and cobB/pCA24N were cultured to a turbidity of 0.05 at 600 nm and grown 2 h. Then, 0.1 mM IPTG was added for another 4 h to induce cobB expression, and then the cells were exposed to 20 mM H2O2 for 10 min. Cell pellets were collected and resuspended in RNAlater (Ambion Inc., Austin, TX), and total RNA was isolated using the RNeasy Mini Kit (Qiagen Inc., Valencia, CA). The E. coli GeneChip Genome 2.0 array (Affymetrix, P/N 900551) was used, and cDNA synthesis, fragmentation, and hybridizations were performed as described previously. If the gene with the larger transcription rate did not have a consistent transcription rate based on the 11-15 probe pairs (P-value less than 0.05), these genes were discarded. A gene was considered differentially expressed when the P-value for comparing two chips was lower than 0.05 (to assure that the change in gene expression was statistically significant and that false positives arise less than 5%) and if their fold change is higher than the standard deviation for the whole genome.