Escherichia coli str. K-12 substr. MG1655
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ABSTRACT:
PROVIDER: PRJNA280772 | ENA |
REPOSITORIES: ENA
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Project description:The present work was devoted to a multi-level characterization of E. coli exposed to Ag+-mediated stress using for the first time an approach of integrative biology, based on the combination of physiological, biochemical and transcriptomic data sets. Bacterial growth and survival after Ag+ exposure were first quantified and related to the accumulation of intracellular silver, as detected by Nano Secondary Ion Mass Spectroscopy (NanoSIMS) at high lateral resolution. The whole transcriptomic response of E. coli cells under ionic silver-mediated stress was then characterized. Clear correlations were established between (i) cell physiology, (ii) variations in the biochemical characteristics of cell fatty acids and proteins, and (iii) regulation of gene expression. This challenging approach allowed determining key genetic markers of the E. coli response to ionic silver. In particular, we identified Ag+-mediated regulations of gene expression in correlation with growth (e.g. genes of transporters, transcriptional regulators, ribosomal proteins), necessary for ionic silver transport and detoxification (e.g. copA, cueO, mgtA, nhaR) and to cope with various stress (dnaK, pspA, metA,R, oxidoreductase genes). Regulation of gene expression after Ag+ exposure was also correlated to macromolecular modifications, such as acyl chain length (e.g. fadL, lpxA, arnA), protein secondary structure (e.g. dnaJ, htpX, degP) and cell morphology (e.g. ycfS, ycbB).
2017-02-09 | GSE67735 | GEO
Project description:The current study deals to decipher the antibacterial mechanism of lysozyme coated silver nanoparticles (L-Ag NPs) (coated with lysozyme) against a Gram negative modal organism Escherichia coli K12 (MTCC 1302). Hence, the whole transcriptome profiling of E. coli K12 was done by exposing it to the MIC75 concentration of L-Ag NPs for 5 and 30 min., by RNA sequencing (RNAseq) analysis. The obtained results were utilized to understand all the metabolic pathways, signaling and molecular functions in bacterial cells under the stress of L-Ag NPs. RNAseq showed a high number of total reads along with significant ratio of high-quality reads, which confirmed the excellent quality and quantity of the obtained RNAseq data. Controlled release of ions from the surface of L-Ag NPs allowed the bacterial cells to function normally till the accumulation of threshold amount of silver ions which triggered the action of defence system, thus, reducing the chances of resistance development in bacteria. In long term, such treatment may force the bacterial machinery to induce changes in their genome to counteract the situation and develop resistance against silver ions, similar to the well-known antibiotic resistance problem. The obtained results advocate that L-Ag NPs can be used as effective antibacterial agent.
2022-06-15 | GSE151954 | GEO
Project description:Experimental Evolution of Silver Resistance in Escherichia coli
| PRJNA299495 | ENA
Project description:Expression profiles of wild-type and SgrR mutant E. coli strains under aMG and 2-DG-induced stress. Expression profiles of E. coli overexpressing SgrS sRNA.
2013-03-26 | GSE45443 | GEO
Project description:Antibiotics induce redox-related physiological alterations as part of their lethality
| PRJNA242527 | ENA
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna. Four replicates each of five toxicant exposure groups of ~20 animals and four replicates of control, unexposed animals. Each control was compared to each exposed data set for a total of 16 comparisons per chemical condition.
2013-12-31 | E-GEOD-47064 | biostudies-arrayexpress
Project description:Expression profiles of wild-type and SgrR mutant E. coli strains under aMG and 2-DG-induced stress. Expression profiles of E. coli overexpressing SgrS sRNA. Illumina RNA-Seq of total RNA extracted from wild-type, SgrR/SgrS mutant and SgrS overexpressing E. coli strains grown in different conditions.
2013-03-26 | E-GEOD-45443 | biostudies-arrayexpress
Project description:Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk- and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24h of exposure, but with a recovery at 48h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24h, but not at 48h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms. mRNA profiles of whole zebrafish embryos at 24 and 48 hours post-fertilisation (hpf) exposed to silver in nano, bulk and ionic forms were generated by deep sequencing using HT-SuperSAGE (Illumina GA2).
2013-06-17 | E-GEOD-38125 | biostudies-arrayexpress
Project description:Overlapping and unique responses of E. coli to adverse conditions
| PRJNA107139 | ENA
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna.
2013-12-31 | GSE47064 | GEO