Project description:Transcripitonal profiling of Escherichia coli K-12 W3110 comparing wild type and luxS mutants without or with 10%, 30% H2O2 treatments, two biological replicates for each condition
Project description:Transcripitonal profiling of Escherichia coli K-12 comparing luxS mutant LW12 with wild type W3110 One-condition experiment, luxS mutant LW12 vs. wild type W3110
Project description:Transcriptional profiling of Escherichia coli K-12 comparing luxS mutant LW12 with wild type W3110 exposure to 10mM or 30mM hydrogen peroxide.
Project description:Transcriptional profiling of Escherichia coli K-12 comparing luxS mutant LW12 with wild type W3110 exposure to 10mM or 30mM hydrogen peroxide. Two-condition experiment, luxS mutant LW12 vs. wild type W3110, treatment with 10mM hydrogen peroxide for 30min or treatment with 30mM hydrogen peroxide for 30min. Two biological replicates.
Project description:Transcripitonal profiling of Escherichia coli K-12 W3110 comparing wild type and luxS mutants without or with 10%, 30% H2O2 treatments, two biological replicates for each condition two-variables experiments: samples without or with treatment of 10% or 30% H2O2 for 30min; wild type and luxS mutants
Project description:The bacterial quorum-sensing autoinducer 2 (AI-2) has received intense interest because the gene for its synthase, luxS, is common among a large number of bacterial species. We have identified luxS-controlled genes in Escherichia coli under two different growth conditions using DNA microarrays. Twenty-three genes were affected by luxS deletion in the presence of glucose, and 63 genes were influenced by luxS deletion in the absence of glucose. Minimal overlap among these gene sets suggests the role of luxS is condition dependent. Under the latter condition, the metE gene, the lsrACDBFG operon, and the flanking genes of the lsr operon (lsrR, lsrK, tam, and yneE) were among the most significantly induced genes by luxS. The E. coli lsr operon includes an additional gene, tam, encoding an S-adenosyl-l-methionine-dependent methyltransferase. Also, lsrR and lsrK belong to the same operon, lsrRK, which is positively regulated by the cyclic AMP receptor protein and negatively regulated by LsrR. lsrK is additionally transcribed by a promoter between lsrR and lsrK. Deletion of luxS was also shown to affect genes involved in methionine biosynthesis, methyl transfer reactions, iron uptake, and utilization of carbon. It was surprising, however, that so few genes were affected by luxS deletion in this E. coli K-12 strain under these conditions. Most of the highly induced genes are related to AI-2 production and transport. These data are consistent with the function of LuxS as an important metabolic enzyme but appear not to support the role of AI-2 as a true signal molecule for E. coli W3110 under the investigated conditions. Experiment Overall Design: Total RNA was extracted from E. coi W3110 wild type and luxS mutant grown in LB plus 0.8% glucose at OD 1.0. The genomic expression was compared between the two strains using Affymetrix E. Coli antisense genome array.
Project description:The bacterial quorum-sensing autoinducer 2 (AI-2) has received intense interest because the gene for its synthase, luxS, is common among a large number of bacterial species. We have identified luxS-controlled genes in Escherichia coli under two different growth conditions using DNA microarrays. Twenty-three genes were affected by luxS deletion in the presence of glucose, and 63 genes were influenced by luxS deletion in the absence of glucose. Minimal overlap among these gene sets suggests the role of luxS is condition dependent. Under the latter condition, the metE gene, the lsrACDBFG operon, and the flanking genes of the lsr operon (lsrR, lsrK, tam, and yneE) were among the most significantly induced genes by luxS. The E. coli lsr operon includes an additional gene, tam, encoding an S-adenosyl-l-methionine-dependent methyltransferase. Also, lsrR and lsrK belong to the same operon, lsrRK, which is positively regulated by the cyclic AMP receptor protein and negatively regulated by LsrR. lsrK is additionally transcribed by a promoter between lsrR and lsrK. Deletion of luxS was also shown to affect genes involved in methionine biosynthesis, methyl transfer reactions, iron uptake, and utilization of carbon. It was surprising, however, that so few genes were affected by luxS deletion in this E. coli K-12 strain under these conditions. Most of the highly induced genes are related to AI-2 production and transport. These data are consistent with the function of LuxS as an important metabolic enzyme but appear not to support the role of AI-2 as a true signal molecule for E. coli W3110 under the investigated conditions. Experiment Overall Design: Total RNA was extracted from E. coi W3110 wild type and luxS mutant grown in LB at OD 2.4. The genomic expression was compared between the two strains using Affymetrix E. Coli antisense genome array.
Project description:To understand cell responses against high succinate stress, a continuous culture was performed for 9 months using a wild Escherichia coli under gradually increasing succinate stress. The final adapted strain against high succinate stress, named DST160, was able to grow with no lag phase in medium containing 1.35 M of succinate stress while wild W3110 showed more than 38 h lag phase. The maximum growth rate and growth yield of DST160 under the stress condition were 0.20 h-1 and 0.192 g-cell/g-glucose, which were 53.8 % and 12.3 % higher than those of W3110 (0.13 h-1 and 0.171 g-cell/g-glucose, respectively).