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:The effect of an extracellular acid shift on gene expression profiles of Escherichia coli K-12 W3110 was observed using Affymetrix E. coli arrays. In order to maximize aeration and maintain logarithmic growth, the overnight culture (LBK broth medium) was diluted 500-fold into a 250-ml baffled flask containing 55 ml of 20mM HOMOPIPES buffered medium (pH 7.6). Cultures were grown to OD600=0.2. A shift to acid external pH was conducted by rapid addition of 840 µl 1M HCl, which lowered the pH of the medium to pH 5.5. For each of five biological replicates, 10-ml samples were taken at times 0, 1, 5, and 10 min post addition of HCl. Each sample was added to 1 ml 10% phenol-ethanol stop solution in <5 sec. For each sample, cDNA synthesized from total RNA was hybridized onto Affymetrix E. coli arrays. Model-based gene expression intensities were determined using GCOS software. Gene-by-gene temporal differential expression was analyzed as a mixed-effects model using polynomial time functions as fixed effects and flask variation as a random effect. Keywords: Time Course
Project description:This dataset is part of a study aimed at developing algorithms for the quantification of stable isotope content in microorganisms after labeling them with stable isotope-labeled substrates. For this dataset Escherichia coli cultures were labeled with 2.5 % of 15N-labeled NH4Cl and grown either anaerobically or aerobically. Cultures of E. coli were grown in M9 minimal medium in which 2.5 % of the ammonium was replaced with 15N-labeled NH4Cl for >10 generations to achieve close to complete labeling of cells. Triplicate cultures were grown. Please note that the unlabeled ammonium that was used of course had a natural content of 15N of around 0.4 %, thus the 0% added label samples have an actual 15N content of 0.4 % and all added label is on top of this value. We included a tab delimited table with this submission providing details on all raw files.
Project description:We recently reported that carbon monoxide (CO) has bactericidal activity. To understand its mode of action we analysed the gene expression changes occurring when Escherichia coli, grown aerobically and anaerobically, is treated with the carbon monoxide releasing molecule, CORM-2. The E. coli microarray analysis shows that E. coli CORM-2 response is multifaceted with a high number of differentially regulated genes spread through several functional categories, namely genes involved in inorganic ion transport and metabolism, regulators, and genes implicated in posttranslational modification, such as chaperones. CORM-2 has higher impact in E. coli cells grown anaerobically, as judged by the existence of repressed genes belonging to eight functional classes which are absent in aerobically CORM-2 treated cells. In spite of the relatively stable nature of the CO molecule, our results show that CO is able to trigger a significant alteration in the transcriptome of E. coli which necessarily has effects in several key metabolic pathways.
Project description:Responses of Escherichia coli W3110gyrb234 as they are upshifted to 42C Escherichia coli W3110gyrb234 cells sampled at several time points (2,5, 10, 40 min) as they are shifted to 42 C in LB, vs 0 min before upshift in LB
Project description:The wild-type (grown on galactose or glucose) or msn2/4 mutant (grown on galactose) strains were grown aerobically. At time zero (generation 0) the sparge gas was switched from air to O2-free N2 and samples were harvested after 0 (aerobic control), 0.04, 0.08, 0.19, and 2 generations of anaerobic growth. Keywords: time-course
Project description:Wild type and mutanat Arabiposis plants grown in short days (9L:15D) for 30 days at 21°C, then shifted to long days (16L:8D). Genotypes: Columbia wild type (Col-0) Landsberg erecta (Ler) leafy-12 (lfy-12, in Col-0) constans-2 (co-2, in Ler) flowering locus T-2 (ft-2, in Ler) Time points: 0, 3, 5, and 7 days after shift to long days Keywords = flowering Keywords: time-course
