Peroxide stress in Sigma54 mutant and Wt
Ontology highlight
ABSTRACT:
ORGANISM(S): Lactiplantibacillus plantarum WCFS1 Lactiplantibacillus plantarum
PROVIDER: GSE11351 | GEO | 2008/05/08
SECONDARY ACCESSION(S): PRJNA106569
REPOSITORIES: GEO
Similar Datasets
Project description:Analyses of the Wild type and the sigma 54 mutant strain NZ7306 with and without peroxide treatment: A Lactobacillus plantarum strain with a deletion in the alternative sigma factor 54 (?54) encoding gene rpoN, displayed a 100 fold higher sensitivity to peroxide as compared to its parental strain. This feature could be due to ?54-dependent regulation of genes involved in peroxide stress response. However, transcriptome analyses of the wild type and the mutant strain during peroxide exposure did not support such a role for ?54. Subsequent experiments revealed that the impaired expression of the mannose PTS operon in the rpoN mutant caused the observed increased peroxide sensitivity. Keywords: genetic modification Two conditions were tested in the transcriptome comparison, the condition “peroxide stress exposure” and the condition “deletion of the rpoN-gene”. This resulted in 4 samples: “Wild type normal”, “rpoN-mutant normal”, “Wild type with peroxide”, and “rpoN-mutant with peroxide”. Samples were hybridised against a sample with only one variation, resulting in a total of 4 hybridisations (“Wild type vs Mutant”, “Wild type vs Wild type peroxide”, “Mutant vs Mutant peroxide”, and “Wild type peroxide vs Mutant peroxide”). The experiment was performed in duplicate (duplicates are designated A and B) and in order to discriminate the variation between the duplicates additional hybridisation were performed: “Wild type A vs Wild type B” and “Mutant with peroxide A vs Mutant with peroxide B”. This resulted in a total of 10 hybridisations (2 x 4 and 2).
2008-05-08 | E-GEOD-11351 | biostudies-arrayexpress
Project description:The goal of this study is to characterize a gshF::cam L. plantarum strain NZ7608. From phenotype characterization we have observed that the gene gshF plays a role in hydrogen peroxide resistance in L. plantarum and therefore we wanted to analyze the global transcriptome response of strain NZ7608 towards peroxide and compared this to wild type response. In this experiment we compared two L. plantarum strains: WCFS1 (wild type) and NZ7618 (gshF::cam). Both strains were grown -in duplo- on CDM containing 0.5% glucose at 37 degrees celsius. When cell density reached OD600=1.0 a hydrogen peroxide stress was given to the cultures to a final concentration of 10mM. Samples were taken at times (0 10 and 30 minutes) upon hydrogen peroxide. All withdrawn samples were used for this microarray experiment. Keywords: peroxide, gshF mutant
2008-01-09 | GSE9961 | GEO
Project description:To determine the genes in addition to fimA regulated by sigma 54 by analysing the gene expression profiles of an rpoN mutant compared to the D. nodosus wild-type strain. Keywords: genetic modification
2006-04-18 | GSE3465 | GEO
Project description:In this experiment we analyzed the impact of the disruption of trxB1in Lactobacillus plantarum at the transcriptome level. Furthermore we studied the effect of 3.5 mM peroxide effect on both Lactobacillus plantarum wild type (strain WCFS1) and a trxB1 mutant (strain NZ7608). Keywords: mutant analysis of trxB1, hydrogen peroxide stress
2007-08-09 | GSE8672 | GEO
Project description:The phytopathogen Xylella fastidiosa produces two classes of pili, long type IV pili and short type I pili, which are involved in motility and adhesion. In this work, we have investigated the role of Ï54 factor and its involvement in the regulation of fimbrial biogenesis in X. fastidiosa. An rpoN null mutant was constructed from citrus strain J1a12, and analyses of global gene expression profile by microarrays comparing the wild type and rpoN mutant strains showed that few genes exhibited differential expression. At least one gene, pilA1 (XF2542), which encodes the structural pilin protein of type IV fimbriae, showed decreased expression in the rpoN mutant whereas an operon encoding proteins of type I fimbriae were twofold more expressed in the mutant. Quantitative real time RT-PCR (qRT-PCR) analysis confirmed that pilA1 transcript was significantly reduced in the rpoN mutant. The transcriptional start site of pilA1 was determined by primer extension, and a canonical Ï54-dependent promoter was found upstream of the start site. Genome sequence analysis of X. fastidiosa revealed five paralogues of pilA, but microarray and qRT-PCR data demonstrated that only the pilA1 transcript was significantly affected in the rpoN mutant. The rpoN mutant made more biofilm than the wild type strain and presented a cell-cell aggregative phenotype. These results indicate that Ï54 regulates biofilm formation, probably via differential regulation of genes involved in type IV and type I fimbrial biogenesis. Direct comparison between wild type strain J1a12 and mutant strain rpoN-.
2010-06-25 | E-GEOD-8097 | biostudies-arrayexpress
Project description:In this experiment two strains were compared. The control strain was the wild type strain containing the plasmid, pCD341. pCD341 is an inducible expression vector, a plasmid which can be used to make a bacterium produce a protein of interest. It is called inducible, because the protein of interest will only be produced if an inducer, in this case, IPTG, is present. In the control strain pCD341 is "empty", meaning the gene encoding the protein of interest has not been inserted into the vector, so when you add IPTG nothing will be produced. Because producing plasmid and being exposed to IPTG can stress cells, the wild type strain harboring the "empty" plasmid was used as the control. The experimental strain DL1/pCD341RpoN contained the a "full" vector into which the gene for the sigma factor RpoN was been inserted. Thus when IPTG is added to the growth medium, this strain will overproduce RpoN. RpoN is an alternative sigma factor, a subunit of the RNA polymerase which is required for binding of the polymerase to specific promoters and is therefore required for the transcription of genes with these promoter sequences. Most bacteria have multiple sigma factors, many of which have specialized functions. In many other bacteria, RpoN is required for the expression of genes involved in nitrogen fixation. However, in G.sulfurreducens and myxococcus xanthus, RpoN appears to essential for survival under all conditions tested and its function and promoter specificity are not known. This experiment was performed in order to gain insight into the physiological function of G. sulfurreducens RpoN. Since we could not knock out RpoN, we decided to try overproducing it, hoping that overproducing RpoN would increase expression of genes who's promoters are recognized by RpoN. We took the wild type strain + empty vector and and the wild type strain with the RpoN vector and transferred them both into medium containing IPTG. For this experiment, we used batch cultures, or closed culture containers (no media nutrients or cells flowing in and out). We harvested cells at mid log phase for RNA preparation. There were three biological replicates and two replicate hybridizations were carried out for each. Keywords: cell type comparison
2009-07-13 | GSE8022 | GEO
Project description:The ability of C. albicans TLO genes to mediate oxidative stress responses was characterised by expressing CaTLO1 and CaTLO4 in a C. dubliniensis TLO null mutant. Each complemented strain was grown with and without peroxide. The transcript profile of peroxide vs no peroxide cultures was analysed in 4 biological replicates for both CaTLO1 and CaTLO4.
2018-02-13 | GSE110463 | GEO
Project description:RpoN (σ54) is the key sigma factor for the regulation of transcription of nitrogen fixation genes in diazotrophic bacteria, which include alpha- and beta-rhizobia. Our previous studies showed that a rpoN mutant of the beta-rhizobial strain Paraburkholderia phymatum formed root nodules on Phaseolus vulgaris that were unable to reduce atmospheric nitrogen into ammonia. In an effort to further characterize the RpoN regulon of P. phymatum, transcriptomics was combined with a powerful metabolomics approach. The metabolome of P. vulgaris root nodules infected by the P. phymatum rpoN Fix- mutant revealed statistically significant metabolic changes compared to wild-type Fix+ nodules, including reduced amounts of chorismate and elevated levels of flavonoids. A transcriptome analysis on Fix+ and Fix- nodules – combined with a search for RpoN binding sequences in promoter regions of regulated genes – confirmed the expected control of σ54 on nitrogen fixation genes in nodules. The transcriptomic data also identified additional target genes, whose differential expression was able to explain the observed metabolite changes in a numerous cases. Moreover, the genes encoding the two-component regulatory system NtrBC were downregulated in root nodules induced by the rpoN mutant and contained a putative RpoN binding motif in their promoter region, suggesting direct regulation. The construction and characterization of an ntrB mutant strain revealed impaired nitrogen assimilation in free-living conditions, as well as a noticeable symbiotic phenotype by forming less but heavier nodules on P. vulgaris roots.
2018-06-06 | GSE111993 | GEO
Project description:When performed at single bp resolution, the genome-wide location, occupancy level, and structural organization of DNA binding proteins provides mechanistic insights into genome regulation. Here we use ChIP-exo to provide the first high resolution view of the epigenomic organization of the E. coli transcription machinery and nucleoid structural proteins when cells are growing exponentially and upon rapid reprogramming (acute heat shock). We suggest that indirect readout of DNA shape at the flanks of cognate motifs provide major contributions to site specificity at promoter positions -35/-24 and -10/-12. We examined the site specificity of three sigma factors (RpoD/70, RpoH/32, and RpoN/54), RNA polymerase (RNAP or RpoA, B, C) and two nucleoid proteins (Fis and IHF). Our results confirm and refine reports that RpoD binds most annotated promoters, whereas RpoH and RpoN bind a much smaller subset, each through their cognate motifs. However, only upon heat shock does RpoH becomes active for RNAP recruitment. In contrast, upon heat shock RpoD remains active at its cognate promoters (including at heat shock genes), whereas RpoN remains inactive at its cognate promoters. RpoN binds ~1,000 non-annotated RpoN motifs, which may reflect a large number of condition-specific transcription units. Occupancy patterns of sigma factors and RNAP suggest a common promoter recruitment mechanism that differs from the long-standing views that sigma and RNAP are co-recruited as a complex, and also simultaneously dissociate from promoters. Our findings suggest that sigma factors are recruited and/or maintained at most promoters via an RNAP-independent mechanism. When RNAP arrives, it dwells for a relatively short time before clearing the promoter, leaving sigma behind. Taken together these findings add new dimensions to how sigma factors achieve promoter specificity through DNA sequence and shape and redefine mechanistic steps in regulated promoter assembly in E. coli.
2022-02-21 | GSE189206 | GEO
Project description:There is increasing evidence to support a role for sigma factor 54 (RpoN) in the regulation of stress resistance factors and protein secretion systems important to bacterial transmission and pathogenesis. In enterohemorrhagic E. coli O157:H7, acid resistance and type III secretion are essential determinants of gastric passage and colonization. This study thus described the transcriptome of an rpoN null strain of E. coli O157:H7 (EcJR-8) to determine the influence of RpoN on virulence and stress resistance gene regulation, and further explored its contribution to glutamate-dependent acid resistance (GDAR). Inactivation of rpoN resulted in the growth phase-dependent, differential expression of 104 genes. This included type III secretion structural and regulatory genes encoded on the locus of enterocyte effacement (LEE), as well as GDAR genes gadA, gadBC and gadE. Upregulation of gad transcript levels in EcJR-8 during logarithmic growth correlated with increased GDAR and survival in a model stomach. Acid susceptibility was reconstituted in EcJR-8 complemented in trans with wild-type rpoN. Acid resistance in EcJR-8 was dependent on exogenous glutamate, gadE and rpoS, but was independent of hns. Results also suggest that GDAR may be controlled by RpoN at multiple regulatory levels. This study supports the hypothesis that RpoN is an important regulator of virulence and stress resistance factors in E. coli O157:H7, and is the first to examine the mechanism by which it represses GDAR.
2009-08-08 | GSE17467 | GEO