Oxidative stress dependent regulon of AosR
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PROVIDER: PRJNA675843 | ENA |
REPOSITORIES: ENA
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Project description:Background: During gut colonization, the enteric pathogen C. jejuni has to surmount the toxic effects of reactive oxygen species produced by its own metabolism, by the host immune system and by the intestinal microflora. Elucidation of C. jejuni oxidative stress defense mechanisms is critical for understanding Campylobacter pathophysiology. Results: The mechanisms of oxidative stress defenses in Campylobacter jejuni were characterized by transcriptional profiling, genes mutagenesis, and phenotypic analysis. The transcriptome changes, in response to H2O2, cumene hydroperoxide, or menadione exposure, were found to be oxidant specific and revealed the differential expression of genes belonging to a variety of biological pathways, from the classical oxidative stress defense systems, to the heat shock response, DNA repair and metabolism, fatty acid and capsule biosynthesis, and multidrug efflux pumps. To define the peroxide sensing regulator PerR, an isogenic mutant was constructed and its transcriptome profile compared to the wild-type strain. Sixty-six genes were found to belong to the PerR regulon. PerR appear to regulate gene expression both dependently and independently of the presence of iron and/or H2O2. The perR mutant was affected in its motility and attenuated in the chick colonization model. Mutagenic and phenotypic studies of the superoxide disumutase SodB, the alkyl-hydroxyperoxidase AhpC, and the catalase KatA, revealed their role in oxidative stress defenses and chick gut colonization. Conclusion: This study reveals the interplay between PerR, the iron metabolism and the oxidative stress defenses and highlights their role in the colonization and/or survival of C. jejuni in the chick cecum. Keywords: Transcriptional response to 3 oxidants (H2O2, menadione and cumene hydroperoxide) and characterization of the perR regulon (comparison of the transciptomes from the wild-type and perR mutant).
2010-09-07 | GSE13126 | GEO
Project description:Investigating the oxidative stress response: Candida glabrata strains were stressed with hydrogen peroxide and menadione (causing oxygen radicals) to induce the oxidative stress regulon, which is thought to be upregulated during the oxidative burst inside of phagocytic cells.
2011-01-01 | E-MEXP-2915 | biostudies-arrayexpress
Project description:Background: During gut colonization, the enteric pathogen C. jejuni has to surmount the toxic effects of reactive oxygen species produced by its own metabolism, by the host immune system and by the intestinal microflora. Elucidation of C. jejuni oxidative stress defense mechanisms is critical for understanding Campylobacter pathophysiology. Results: The mechanisms of oxidative stress defenses in Campylobacter jejuni were characterized by transcriptional profiling, genes mutagenesis, and phenotypic analysis. The transcriptome changes, in response to H2O2, cumene hydroperoxide, or menadione exposure, were found to be oxidant specific and revealed the differential expression of genes belonging to a variety of biological pathways, from the classical oxidative stress defense systems, to the heat shock response, DNA repair and metabolism, fatty acid and capsule biosynthesis, and multidrug efflux pumps. To define the peroxide sensing regulator PerR, an isogenic mutant was constructed and its transcriptome profile compared to the wild-type strain. Sixty-six genes were found to belong to the PerR regulon. PerR appear to regulate gene expression both dependently and independently of the presence of iron and/or H2O2. The perR mutant was affected in its motility and attenuated in the chick colonization model. Mutagenic and phenotypic studies of the superoxide disumutase SodB, the alkyl-hydroxyperoxidase AhpC, and the catalase KatA, revealed their role in oxidative stress defenses and chick gut colonization. Conclusion: This study reveals the interplay between PerR, the iron metabolism and the oxidative stress defenses and highlights their role in the colonization and/or survival of C. jejuni in the chick cecum. Keywords: Transcriptional response to 3 oxidants (H2O2, menadione and cumene hydroperoxide) and characterization of the perR regulon (comparison of the transciptomes from the wild-type and perR mutant). To investigate the transcriptional responses of C. jejuni to oxidant exposure, hydrogen peroxide (H2O2), cumene hydroperoxide (CHP), or menadione sodium bisulfite (MND) was added to the 50 ml broth at a final concentration of 1 mM. The same amount of water or DMSO was added to the bacterial culture that served as reference samples for the transcriptional profile study in response to H2O2, MND or CHP. Furthermore, to investigate the transcriptional response of C. jejuni to H2O2 exposure in the presence of excess iron, ferrous sulfate was added to the bacterial culture at a final concentration of 40 µM, 15 min prior to H2O2 exposure. Ten minutes after the addition of the oxidant, total RNA was extracted and processed for microarray hybridization. To identify the PerR regulon, the wild-type strain C. jejuni NCTC 11168 and the perR mutant were grown in 500 ml flasks containing 250 ml of MEMα medium. At mid-log phase, 50 ml of the cultures were transferred to 100 ml flasks and ferrous sulfate and/or H2O2 were added . Ten minutes following the addition of H2O2 the cells were collected and the total RNA extracted.
2010-09-07 | E-GEOD-13126 | biostudies-arrayexpress
Project description:In bacteria the defence system to counter oxidative stress is orchestrated by three transcriptional factors – SoxS, SoxR and OxyR. Although the transcriptional regulon of these factors are known in many bacteria, similar data is not available for K. pneumoniae. To address this data gap, oxidative stress was induced in K. pneumoniae MGH 78578 using paraquat and the corresponding regulon was identified using RNA-seq. Since soxS was significantly induced , a soxS mutant was constructed to decipher this regulon in K. pneumoniae MGH75878. The ‘oxidative SoxS regulon’, comprising common genes differentially regulated genes in oxidative and soxS regulon was identified from both regulons – characterised a stringent group of genes which were regulated by SoxS during oxidative stress. Efflux pump encoding genes like acrAB-tolC, acrE along with marRABwere identified in the oxidative SoxS regulon. The phenotypic effect of the observed efflux pump regulation was confirmed in the soxS mutant that exhibited an 2 fold reduction in the minimum bactericidal concentration (MBC) against tetracycline compared to that of the isogenic wild type. Impaired efflux activity, allowing tetracycline to be accumulated in the cytoplasm to bactericidal levels, was further confirmed using tetraphenylphosphonium (TPP+) ion accumulation assay. The susceptibility of the soxS mutant against tetracycline was also apparent in vivo, in the zebrafish embryo model. We conclude that the soxS gene could be considered as a genetic target against which an inhibitor could be developed and be used in combinatorial therapy with tetracycline to combat infections associated with multi-drug resistant K. pneumoniae.
2021-05-26 | GSE146844 | GEO
Project description:Contribution to the study of oxidative stress markers in laparoscopic vs open colectomy for colorectal cancer
| 2074362 | ecrin-mdr-crc
Project description:Oxidative stress may play a role in normal aging. SKN-1 is a transcription factor necessary for intestine development in Caenorhabditis elegans, which also regulates the response to oxidative stress post-embryonically. Using DNA microarrays, we found that oxidative stress induces the antioxidant response, the heat shock response, and detoxification genes, while the expression of genes involved in homeostasis, development, and reproduction were decreased. Both up-regulated and down-regulated genes can be wholly, partially, or not at all dependent on SKN-1 action. However, induction of the heat shock response by oxidative stress was not affected by SKN-1 removal. Keywords: stress response
2007-11-01 | GSE9301 | GEO
Project description:oxidative stress Methanoperedens nitroreducens
| PRJEB27089 | ENA
Project description:Borrelia burgdorferi regulates gene expression in response to environmental conditions, including temperature, pH, redox potential, and host factors. B. burgdorferi encodes a PerR homologue designated BosR which presumably serves as a global regulator of genes involved in the oxidative stress response. Infectious B. burgdorferi strain B31 is resistant to oxidative stressors in vitro whereas our non-infectious isolate is sensitive due, in part, to a point mutation that converts an arginine to a lysine at residue 39 of BosR. Subsequent insertional inactivation of this bosRR39K allele (bosRR39K::kanR) restores resistance to oxidative stressors. These observations suggest that the B. burgdorferi non-infectious bosRR39K::kanR strain may transcribe genes that are also expressed in infectious B. burgdorferi cells, but are repressed in the bosRR39K background, thus explaining the different oxidative stress phenotypes observed between these isolates. To test this hypothesis, macroarray technology and quantitative RT-PCR was utilized to compare the transcriptional profiles from the isogenic bosRR39K and bosRR39K::kanR isolates. Array data indicated that 88 ORFs were significantly expressed in the absence of BosRR39K. Since most genes affected mapped to the chromosome, it is likely that these genes define an important physiologic response for B. burgdorferi. Included within the genes identified was the detoxification gene sodA as well as other loci not overtly linked to oxidative stress. These results suggest that a putative BosR regulon, as defined by the bosRR39K allele, is required to combat toxic oxidative intermediates, but may also be involved in adaptive strategies that are independent of reactive oxygen species. Keywords: genetic modification
2006-05-30 | GSE4856 | GEO
Project description:Study of Oxidative stress Markers (F2 Isoprostanes for lipid peroxidation, Carbonyl groups for protein peroxidation, 3 Nitrotyrosine for damage by nitrogens, and 8-Hydroxyguanosine for RNA peroxidation)in patients with colorectal cancer undergo surgical treatment (preoperatively during the intervention and postoperatively) and controls.
| 2115584 | ecrin-mdr-crc
Project description:BRG1 attenuates colonic inflammation and tumorigenesis through autophagy-dependent oxidative stress sequestration
| PRJNA557213 | ENA