Project description:In this work, we describe a nonsense mutation in SME1 that alleviates photorespiratory cell death in the Arabidopsis thaliana cat2-2 mutant. A SME1 loss-of-function mutant (sme1-1) and wild-type Col-0 were subjected to mRNA-seq for differential gene expression and alternative splicing analysis. This revealed a massive transcript reprogramming and occurrence of splicing defects caused by SME1 deficiency. For more details see the publication.
Project description:Hepatocellular carcinoma (HCC) cells show increased resistance to various stress conditions such as oxidative stress. Conventional therapies have low efficacies due to resistance and off-target effects in HCC. Here we aimed to analyze oxidative stress-related gene expression profiles of two HCC cell lines. To identify important genes that cause resistance to reactive oxygen species (ROS), a model of oxidative stress upon selenium (Se) deficiency was utilized in which an affymetrix microarray data was generated for two isogenic HCC cell lines - HepG2 and HepG2-2.2.15 (Head-to-Tail HBV genome integration) that are either sensitive or resistant to Se deficiency dependent oxidative stress, respectively.
Project description:Broadly distributed species must cope with diverse and changing environmental conditions, including various forms of stress. Cosmopolitan populations of Drosophila melanogaster are more tolerant to oxidative stress than those from the species’ ancestral range in sub-Saharan Africa, and the degree of tolerance is associated with an insertion/deletion polymorphism in the 3’ untranslated region of the Metallothionein A (MtnA) gene that varies clinally in frequency. We examined oxidative stress tolerance and the transcriptional response to oxidative stress in cosmopolitan and sub-Saharan African populations of D. melanogaster, including paired samples with allelic differences at the MtnA locus. We found that the effect of the MtnA polymorphism on oxidative stress tolerance was dependent on the genomic background, with the deletion allele increasing tolerance only in a northern, temperate population. Genes that were differentially expressed under oxidative stress included MtnA and other metallothioneins, as well as those involved in glutathione metabolism and other genes known to be part of the oxidative stress response or the general stress response.
Project description:Perturbation of the cellular redox state by stress conditions is sensed by redox-sensitive proteins so that the cell can physiologically respond to stressors; however, the mechanisms linking sensing to response remain poorly understood in plants. Here we report that the transcription factor bZIP68 underwent in vivo oxidation in Arabidopsis cells under oxidative stress which is dependent on its redox-sensitive Cys320 residue. bZIP68 is primarily localized to the nucleus under normal conditions in Arabidopsis seedlings and oxidative stress reduces its accumulation in the nucleus and increases its cytosolic localization. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) revealed that bZIP68 primarily binds to promoter regions containing the core G-box (CACGTG) or G-box-like motif of the genes involved in abiotic and biotic stress responses, photosynthesis, biosynthetic processes, and transcriptional regulation. The bzip68 mutant displayed slower growth but enhanced tolerance to oxidative stress. The results from the ChIP-seq and phenotypic and transcriptome comparison between the bzip68 mutant and wildtype indicate that bZIP68 normally suppresses expression of stress tolerance genes and promotes expression of growth-related genes, whereas its inactivation enhances stress tolerance but suppresses growth. bZIP68 might balance stress tolerance with growth through the extent of its oxidative inactivation according to the environment.
Project description:E. coli frequently encounters oxidative stress both in its natural environment or in industrial biotechnology. Elucidating the mechanisms behind tolerance to oxidative stress would be beneficial for understanding pathogenesis as well as improving production strain fitness. We make use of adaptive laboratory evolution to develop two strains of E. coli which exhibit 500% increased tolerance to paraquat stress compared to wild type. Evolved strains tolerate oxidative stress by reduction of flux through TCA, dyregulation of iron-uptake genes, and up-regulation of cell motility or iron-sulfur cluster repair genes.
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.
Project description:Calcium-dependent protein kinase (CPK) family is involved in diverse functions including abiotic tolerance, however, biological functions of some CPK members have not been clarified. In our previous study, abundance of a wheat CPK protein (TaCPK34) was remarkably induced during both grain and leaf organs of wheat plants suffering from various abiotic and biotic stresses, inferring its function involved in abiotic and biotic tolerance. In present study, its function involved in abiotic tolerance was further verified. Using Agroinfiltration-mediated transient transformation, TaCPK34 protein localizes to the plasma membrane in N. benthamina leaves. Its transcripts were significantly increased during 20% PEG-induced water deficiency, and its barley stripe mosaic virus-induced silencing wheat plants exhibited more sensitive phenotype to natural drought stress, suggesting that it could play key role in response to water deficiency in wheat. Isobaric tagging for relative and absolute quantification (iTRAQ) proteomic method further revealed that, in leaves of BSMV-VIGS-induced TaCPK34 silencing wheat plants, 48 protein species exhibiting significantly altered abundance were identified during water stress condition. The identified protein species were related to diverse functions (e.g. stress and defense, carbohydrate metabolism, nucleotide metabolic, photosynthesis, transportation, protein metabolism, signal transduction, lipid and phosphate metabolism), suggesting its potential regulatory mechanism. Our results provided insights on molecular mechanism of TaCPK34 on abiotic tolerance in higher plants.
Project description:The bacterium Bacillus subtilis is of high importance both as a model organism for Gram-positive bacteria and as an industrial work horse in the production of biomolecules. In recent years, advancements have been made to engineer the bacterium even further towards industrial applications. In this study, we present a novel screening method for mutant libraries using diamide, an oxidising agent that binds free thiols and creates disulfide bonds between them, thereby causing a so-called ‘disulfide stress’ in bacteria. The method shows promise to selectively identify phenotypes in B. subtilis with improved tolerance towards oxidative and disulfide-associated stress. Phenotypes initially identified by transposon mutagenesis were recreated through targeted gene deletions. Among the resulting deletion mutants, the largest difference in diamide tolerance compared to the parental strain was observed for pfkA and ribT deletion strains. A proteomics analysis showed that that diamide tolerance can be achieved through different routes involving increased expression of stress management proteins and reduced availability or activity of the RNA degradosome. We conclude that our screening method allows the facile identification of Bacillus strains with improved oxidative stress tolerance phenotypes