RNA-seq analysis of isogenic dnaN+ and dnaN-E202K E. coli strains derived from MG1655.
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ABSTRACT:
ORGANISM(S): Escherichia coli
PROVIDER: GSE175936 | GEO | 2021/06/02
REPOSITORIES: GEO
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Project description:RNA-seq analysis of isogenic dnaN+ and dnaN-E202K E. coli strains derived from MG1655.
| PRJNA734325 | ENA
Project description:overexpressing DnaN did not affect the genomic DNA pattern in a strain that replicated form the plasmid origin of replication oriN and is deleted for the endogenous origin of replication oriC
2009-09-01 | GSE17809 | GEO
Project description:Overexpression of DnaN causes the accumulation of origin of replication proximal DNA.
2009-09-01 | GSE17808 | GEO
Project description:Abstract — Within the US military, new insensitive munitions (IMs) are rapidly replacing conventional munitions improving safety from unintended detonation. Toxicity data for IM chemicals are expanding rapidly, however IM constituents are typically deployed in mixture formulations, and very little is known about their mixture toxicology. In the present study we sought to characterize the mixture effects and toxicology of the two predominant IM formulations IMX-101 and IMX-104 in acute (48 h) larval fathead minnow (Pimephales promelas) exposures. IMX-101 consists of a mixture of 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ) while IMX-104 is composed of DNAN, NTO, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). DNAN was the most potent constituent in IMX-101 eliciting an LC50 of 36.1 mg/L, whereas NTO and NQ did not elicit significant mortality in exposures up to 1040 and 2640 mg/L, respectively. Toxic unit calculations indicated that IMX-101 elicited toxicity representative of the component concentration of DNAN within the mixture. Toxicogenomic responses for the individual constituents of IMX-101 indicated unique transcriptional expression and functional responses characteristic of: oxidative stress, impaired energy metabolism, tissue damage and inflammatory responses in DNAN exposures; impaired steroid biosynthesis and developmental cell-signaling in NQ exposures; and altered mitogen-activated protein kinase signaling in NTO exposures. Transcriptional responses to the IMX-101 mixture were driven by the effects of DNAN where expression and functional responses were nearly identical comparing DNAN alone versus the fractional equivalent of DNAN within IMX-101. Given that each individual constituent of the IMX-101 mixture elicited unique functional responses, and NTO and NQ did not interact with DNAN within the IMX-101 mixture exposure, the overall toxicity and toxicogenomic responses within acute exposures to the IMX-101 formulation are indicative of "independent" mixture toxicology. Alternatively, in the IMX-104 exposure both DNAN and RDX were each present at concentrations sufficient to elicit lethality (RDX LC50 = 28.9 mg/L). Toxic-unit calculations for IMX-104 mixture formulation exposures indicated slight synergistic toxicity (ΣTU LC50 = 0.82, 95% confidence interval = 0.73-0.90). Unique functional responses relative to DNAN were observed in the IMX-104 exposure including responses characteristic of RDX exposure. Based on previous transcriptomics responses to acute RDX exposures in fathead minnow larvae, we hypothesize that the potentially synergistic responses within the IMX-104 mixture are related to interactive effects of each DNAN and RDX on oxidative stress mitigation pathways.
2018-03-01 | GSE101870 | GEO
Project description:Abstract - Current in vitro hazard assessment techniques lack the systems context necessary to holistically describe in vivo toxicity. To remedy this shortcoming, we have employed the Integrated discrete Multiple Organ Co-Culture (IdMOC) system in conjunction with global-transcriptomic expression assessment to provide a systems context of interactive organ and toxicity pathway responses. Specifically, IdMOC exposures containing human cells representative of five organ types (kidney, liver, lung, vascular endothelium and heart muscle) were compared to mono-culture exposures, to evaluate toxic effects in a well-studied legacy munition, 2,4,6-trinitrotoluene (TNT) compared to a structurally similar insensitive munition, 2,4-dinitroanisole (DNAN) having sparsely described toxicity. DNAN toxicity, based on cell viability, was significantly lower than TNT for three cell lines: liver, vascular endothelium, and heart. Toxicity pathways enriched in transcriptional analysis of kidney cells exposed to TNT and DNAN through the IdMOC system reflected the literature-based in vivo mammalian toxicity of parent compounds and metabolites where multiple screening values matched chronic dosing levels within 1 order of magnitude. Enriched pathways were primarily unique to each chemical where TNT exposures affected xenobiotic metabolism, oxidative stress, and cell cycle pathways in addition to pathways providing potential screening for hematotoxicity, renal toxicity and urinary cancer. Ten pathway-level responses from IdMOC suggested that DNAN elicited toxicity representative of the primary metabolite, 2,4-dinitrophenol (2,4-DNP). Relative to monoculture, IdMOC results provided a higher number and more robust enrichment of pathways involved in known in vivo toxicity mechanisms for TNT and a profile indicative of in vivo systemic toxicity of DNAN and metabolite 2,4-DNP.
2018-12-01 | GSE90617 | GEO
Project description:We used the soil nematode Caenorhabditis elegans, a well-characterized genomics model organism, as the test organism and a species-specific, genome-wide 44K-oligo probe microarray for gene expression analysis. Our goal was to discern toxicological mechanisms for three insensitive munitions formulation IMX-101 constituents 2,4-dinitroanisole (DNAN), nitroguanidine (NQ) and nitrotriazolone (NTO) at the molecular level.
2017-06-01 | GSE92365 | GEO
Project description:Bacteria growing as surface-adherent biofilms are better able to withstand chemical and physical stresses than their unattached, planktonic counterparts. Using transcriptional profiling and quantitative PCR, we observed a previously uncharacterized gene, yjfO, to be upregulated during Escherichia coli MG1655 biofilm growth in a chemostat on serine-limited defined medium. A yjfO mutant, developed through targeted insertion mutagenesis, and a yjfO-complemented strain, were obtained for further characterization. While bacterial surface colonization levels (CFU/cm2) were similar in all three strains, the mutant strain exhibited reduced microcolony formation when observed in flow cells, and greatly enhanced flagellar motility on soft (0.3%) agar. Complementation of yjfO restored microcolony formation and flagellar motility to wild type levels. Cell surface hydrophobicity and twitching motility were unaffected by the presence or absence of yjfO. In contrast to the parent strain, biofilms from the mutant strain were less able to resist acid and peroxide stresses. yjfO had no significant effect on E. coli biofilm susceptibility to alkali or heat stress. Planktonic cultures from all three strains showed similar responses to these stresses. Regardless of the presence of yjfO, planktonic E. coli withstood alkali stress better than biofilm populations. Complementation of yjfO restored viability following exposure to peroxide stress, but did not restore acid resistance. Based on its influence on biofilm formation, stress response, and effects on motility, we propose renaming the uncharacterized gene, yjfO, as bsmA (biofilm stress and motility).
2009-10-17 | GSE18362 | GEO
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 ?fnr mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the FNR protein. WT strains were grown under aerobic and anaerobic growth conditions.
2013-06-20 | GSE41189 | GEO
Project description:We replaced the natural pnp locus with the human cDNA and studied the transcriptomes of 3 strains, namely the wt pnp+ (C-1a), the mutant with pnp ORF deletion (C-5691) and the strain with the substitution of the bacterial ORF with the human one (C-6001).
2023-08-08 | GSE211960 | GEO
Project description:Investigation of whole genome gene expression level changes in a Escherichia coli MG1655 K-12 ∆arcA mutant, compared to the wild-type strain. The mutations engineered into this strain produce a strain lacking the ArcA protein. The results are further described in the manuscript The response regulator ArcA uses a diverse binding site architechture to globally regulate carbon oxidation in E. coli
2013-10-17 | GSE46412 | GEO