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ABSTRACT:
PROVIDER: PRJNA1272773 | ENA |
REPOSITORIES: ENA
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Project description:Hexavalent chromium (Cr(VI)) is a highly toxic contaminant, some bacteria are able to transform it to less toxic and less soluble trivalent chromium (Cr(III)). Klebsiella sp. strain AqSCr, isolated from Cr(VI)-polluted groundwater, reduces Cr(VI) both aerobically and anaerobically, and resists up 35 mM of Cr(VI); Subculturing of AqSCr in the presence of Cr(VI) conduces to adaptation. In this study, we performed RNA-Seq of Cr(VI) adapted stage, finding 255 genes upregulated and 240 downregulated with respect to controls without Cr(VI). Genes differentially expressed are mostly associated with oxidative stress response, DNA repair and replication, sulfur starvation response, envelope-osmotic stress response, fatty acid metabolism, ribosomal subunits and energy metabolism. Among them, genes not previously associated with chromium resistance as cybB, encoding a putative superoxide oxidase, gltA2, encoding an alternative citrate synthase, and des, encoding a fatty acid desaturase were upregulated. The alternative sigma factors fecl, rpoE and rpoS were upredgulated in Cr(VI) adapted cells, then they participate in orchestate the Cr(VI)-resistance mechanisms in AqSCr strain
2021-05-20 | GSE160968 | GEO
Project description:Chromium (Cr) is a non-essential metal for normal plants and is toxic to plants at high concentration. In spite of many previous studies having been conducted on the effects of Cr stress, the precise molecular mechanisms and signaling pathways of action of Cr remain poorly understood. In this study, the transcriptome at the early of Cr (VI) stress were assayed in rice roots. To gain more insight into these cellular responses, we analyzed whole-genome transcriptome of rice expose to Cr (VI) for 1 and 3 h. Analysis revealed 1,261 and 267 up and down-regulated genes by Cr (VI). Cr (VI) stress triggered changes in transcript levels of genes related to secondary metabolism process, biosynthetic process, specially jasmonic acid biosynthetic process, response to abiotic stress, specially response to toxin, transcription regulator activity, specially transcription factors activity. The most predominant transcription factor families were WRKY, AP2/ERF, NAC, C2H2, MYB. In addition, many protein kinase, including eight MAPKKK, two CDPK, and one MAPK, showed significant increase in transcriptional level under Cr (VI) stress. Molecular mechanisms for the excess Cr(VI) in rice roots Comparison of mock control and rice seedlings treated with 200 M-NM-<M Cr(VI); Biological replicates: 3 control replicates, 3 Cr(VI)-treated replicates.
2013-10-31 | E-GEOD-33376 | biostudies-arrayexpress
Project description:The ability of chromatin to switch back and forth from open euchromatin to closed heterochromatin is vital for transcriptional regulation and genomic stability, and subject to disruption by exposure to environmental agents such as hexavalent chromium. Cr(VI) exposure can cause chromosomal disruption through formation of Cr-DNA adducts, free radical-induced DNA damage, and DNA-Cr-protein and DNA-Cr-DNA cross-links, all of which may disrupt chromatin remodeling mechanisms responsible for maintenance or controlled modification of epigenetic homeostasis. In addition, dose-response analyses have shown that acute exposures to high-concentrations of Cr(VI) and chronic exposures to low-concentrations of the same agent lead to significantly different transcriptomic and genomic stability outcomes. To investigate how transcriptional responses to chromium exposure might correlate to structural changes in chromatin, we have used whole genome Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) analysis coupled with deep sequencing to identify regions of the genome that switch from open to closed chromatin or vice versa in response to exposure to varying Cr(VI) concentrations. We find that the switch affects gene expression levels in the target areas that vary depending on Cr(VI) concentration. At either Cr(VI) concentration, chromatin domains surrounding binding sites for AP-1 transcription factors become significantly open, treatment whereas BACH2 and CTCF binding sites are open solely at the low and high concentrations, respectively. Our results suggest that FAIRE may be a useful technique to map chromatin elements targeted by DNA damaging agents for which there is no prior knowledge of their specificity, and to identify subsequent transcriptomic changes induced by those agents.
2014-04-10 | GSE56636 | GEO