Project description:Transcripitonal profiling of Escherichia coli K-12 W3110 comparing cells with and without hydrogen peroxide treatment, two biological replicates each
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:Transcripitonal profiling of Escherichia coli K-12 W3110 comparing cells with and without hydrogen peroxide treatment, two biological replicates each One-condition experiment, cells with or without hydrogen peroxide treatment for 10min
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:Peroxynitrite is formed in macrophages by the diffusion-limited reaction of superoxide and nitric oxide. This highly reactive species is capable of causing both oxidative and nitrosative stress in Escherichia coli. Previous studies have focused on the reactions of peroxynitrite with specific proteins or the effects of peroxynitrite on the growth and viability of whole cells. This work shows for the first time the transcriptomic response of E. coli to peroxynitrite, highlighting specific areas targeted by the stress. Upregulation of the cysteine biosynthesis pathway and subsequent identification of an increase in S-nitrosothiol levels suggests S-nitrosylation as a consequence of peroxynitrite exposure. Genes involved in the assembly / repair of iron-sulfur clusters also show enhanced transcription identifying another target of this reactive species. Unexpectedly arginine biosynthesis gene transcription levels were also elevated after treatment with peroxynitrite. Analysis of the negative regulator for these genes, ArgR, showed that the post-translational nitration of tyrosine residues within this protein is responsible for its degradation in vitro. Further upregulation is seen in oxidative stress response genes including katG and ahpCF. Probabilistic modelling of this data identified 5 altered transcription factors in response to peroxynitrite exposure including OxyR and ArgR. Hydrogen peroxide can be present as a contaminant in commercially available peroxynitrite preparations. Transcriptomic analysis of cells treated with hydrogen peroxide also showed an upregulation of oxidative stress response genes; however it did not show increased transcription of many other genes which are upregulated by peroxynitrite suggesting that cellular responses to peroxynitrite and hydrogen peroxide are distinct.
Project description:Escherichia coli culture was subjected to two different types of nutritional scenarios, abundant carbon/ nitrogen sources and scarce carbon/nitrogen medium. Study revealed that scarce medium adapted culture were more tolerant to hydrogen peroxide than abundant medium.
Project description:The transcriptomic response of Jurkat T lymphoma cells to hydrogen peroxide was investigated to determine the global effects of hydrogen peroxide on cellular gene expression.
Project description:Salmonella enterica serovar Typhimurium is a Gram-negative bacterium, facultative anaerobe and intracellular pathogen that causes enteric fever in mice. Once orally ingested, Salmonella invades and traverse the mucosal intestinal epithelia, where it is phagocytized by specialized cells including macrophages, dendritic cells and neutrophils. Within these cells, the bacterium is kept in a compartment termed Salmonella containing vacuole where it is exposed to different adverse conditions including nutrient deprivation, acid pH, reactive oxygen (ROS) as well as nitrogen (RNS) species and low oxygen levels. Among the signals encountered by the bacteria, oxidative stress is one of the main challenges that it has to overcome in order to survive. In this context, the OxyR and SoxRS proteins are the most studied regulators involved in response to ROS. However, in the past years growing evidence suggests that the ArcAB two-component system might play a key role in modulating gene expression in response to ROS. Furthermore, the global regulator ArcA is required for the resistance of Escherichia coli, S. Enteritidis and Typhimurium to hydrogen peroxide (H2O2), however, the ArcA regulon under oxidative stress conditions remains elusive. Therefore, the aim of this work was to demonstrate that ArcAB regulates the expression of genes in response to hydrogen peroxide and determine the ArcA regulon under this condition. To achieve this, we evaluated transcriptomic changes in strain 14028s, ∆arcA in response to H2O2. Total RNA was harvested from three biological replicates of wt and arcA mutant cultures exposed or unexposed to 1.5 mM hydrogen peroxide for 20 min in LB medium.
Project description:Peroxynitrite is formed in macrophages by the diffusion-limited reaction of superoxide and nitric oxide. This highly reactive species is capable of causing both oxidative and nitrosative stress in Escherichia coli. Previous studies have focused on the reactions of peroxynitrite with specific proteins or the effects of peroxynitrite on the growth and viability of whole cells. This work shows for the first time the transcriptomic response of E. coli to peroxynitrite, highlighting specific areas targeted by the stress. Upregulation of the cysteine biosynthesis pathway and subsequent identification of an increase in S-nitrosothiol levels suggests S-nitrosylation as a consequence of peroxynitrite exposure. Genes involved in the assembly / repair of iron-sulfur clusters also show enhanced transcription identifying another target of this reactive species. Unexpectedly arginine biosynthesis gene transcription levels were also elevated after treatment with peroxynitrite. Analysis of the negative regulator for these genes, ArgR, showed that the post-translational nitration of tyrosine residues within this protein is responsible for its degradation in vitro. Further upregulation is seen in oxidative stress response genes including katG and ahpCF. Probabilistic modelling of this data identified 5 altered transcription factors in response to peroxynitrite exposure including OxyR and ArgR. Hydrogen peroxide can be present as a contaminant in commercially available peroxynitrite preparations. Transcriptomic analysis of cells treated with hydrogen peroxide also showed an upregulation of oxidative stress response genes; however it did not show increased transcription of many other genes which are upregulated by peroxynitrite suggesting that cellular responses to peroxynitrite and hydrogen peroxide are distinct. Biological experiments (i.e. a comparison of control and plus peroxynitrite cells) were carried out three times, and a dye swap performed for each experiment, providing two technical repeats for each of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed ≥ twofold and displayed and P value of < 0.05 (as determined by a t test) were defined as being statistically significantly differentially transcribed. Additional biological experiments (i.e. a comparison of control and plus hydrogen peroxide cells) were carried out three times, and a dye swap performed for each experiment, providing two technical repeats for each of the three biological repeats. Data from the independent experiments were combined. Genes that were differentially expressed ≥ twofold and displayed and P value of < 0.05 (as determined by a t test) were defined as being statistically significantly differentially transcribed.