Project description:This SuperSeries is composed of the following subset Series: GSE5075: Aerobic transcriptional responses of Escherichia coli to NO under defined chemostat conditions. GSE5076: Anaerobic transcriptional responses of Escherichia coli to NO under defined chemostat conditions. GSE5084: Anaerobic NO-exposed Chemostat Comparison of Wt & norR mutant Responses GSE5137: Aerobic NO-exposed Chemostat Comparison of Wt & norR mutant Responses GSE5139: Aerobic NO-exposed Chemostat Comparison of Wt & hmp mutant Responses Keywords: SuperSeries Refer to individual Series
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 ?fnr mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the FNR protein. WT strains were grown under aerobic and anaerobic growth conditions.
Project description:Escherichia coli strain MG1655 was grown in parallel chemostat cultures in GGM. In one chemostat the culture was fed adequate Zn; in the other, measures were taken to eliminate Zn from the chemostat vessel and culture medium. Culture volume (120 ml), temperature (37 oC) and stirring speed (437 rpm) were maintained. Steady state values for pH and OD600 were 6.9 and 0.6, respectively. After 50 hours, samples from the adequate Zn and Zn-limited chemostats were harvested into RNAprotect and total RNA was purified using Qiagen’s RNeasy Mini kit (using the supplier’s protocol) prior to use in microarray analysis. Biological experiments (i.e. a comparison of adequate versus low Zn in chemostat culture) were carried out three times, and a dye swap performed for each experiment, providing two technical repeats for each of the three biological repeats.
Project description:Escherichia coli strain MG1655 was grown in a New Brunswick Scientific Bioflow III Biofermentor under continuous culture (chemostat) conditions. Cells were grown in defined media containing 8 mM glycerol as the sole and limiting source of energy and carbon. The working volume was 1 litre, and the dilution rate 0.1 h-1. For aerobic growth, the air-flow rate was 1 l/min, and the dissolved oxygen tension was maintained at 40% air saturation by measuring oxygen dissolved in the culture using a Broadley James D140 OxyProbe® electrode and automated adjustment of stirring rate. Cells were grown as above to steady-state, At steady-state, NOC-5 and NOC-7 was added to the chemostat culture and to the nutrient feed at a final concentration of 10 uM of each unless stated otherwise. Samples were taken immediately prior to the addition of NOCs and after a period of 5 min exposure to NOCs for subsequent analysis using microarrays. Cells were harvested directly into RNA Protect (Qiagen) to stabilize RNA, and total RNA was purified using Qiagenâs RNeasy Mini kit as recommended by the suppliers. Equal quantities of RNA from control and NOC-supplemented cultures were labelled using nucleotide analogues of dCTP containing either Cy3 or Cy5 fluorescent dyes. The average signal intensity and local background correction were obtained using a commercially available software package from Biodiscovery, Inc (Imagene, version 4.0 and GeneSight, version 3.5). The mean values from each channel were log2 transformed and normalised using the Lowess method to remove intensity-dependent effects in the log2(ratios) values. The Cy3/Cy5 fluorescent ratios were calculated from the normalized values. Two biological repeats (ie. two chemostat runs) were grown. Control and exposed samples were taken as described in summary. For each chemostat run 2 hybridisations were performed. One in which the control was Cy3 labelled whilst the exposed was Cy5 labelled, and a dye swap.
Project description:Addition of 3 new arrays made from carbon limited chemostat of CENPK113-7D and 3 new arrays made from aerobic carbon limited chemostat of CENPK113-7D Complmentary data to the data of the serie GSE1723. Keywords: Chemostat-based transcriptome response comparison