Reducing the ionizing radiation background does not significantly affect the evolution of Escherichia coli populations over 500 generations.
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ABSTRACT:
SUBMITTER: Lampe N
PROVIDER: S-EPMC6797783 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Ionizing radiation is a harsh environmental factor that could induce plant aging. We hypothesized that radiation-related aging remodels proteome, particularly triggering the accumulation of prion-like proteins in tissues. The object of this study, pea (Pisum sativum), is an agriculturally important legume. Research on the functional importance of amyloidogenic proteins was never performed on this species. Pea seeds were irradiated by 50 Gy of X-rays. Afterwards, Fourier-transform infrared spectroscopy (FTIR) was used to investigate changes in the secondary structure of proteins in germinated seedlings. Specifically, we evaluated the ratio between the amide I and II peaks. Next, we performed protein staining with Congo red to compare the presence of amyloids in the samples. In parallel, we profiled detergent-resistant proteome fraction by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS). Differentially accumulated proteins were functionally analyzed in MapMan software, and the PLAAC tool was used to reveal putative prion-like proteins. We showed a reduced germination rate, yet higher plant height and faster appearance of reproductive organs in the irradiated group compared with the control; furthermore, we demonstrated more β-sheets and amyloid aggregates in the leaves of stressed plants. We detected 531 proteins in detergent-resistant fraction extracted from roots, and 62 were annotated as putative prion-like proteins. Notably, 29 proteins were significantly differentially abundant between the irradiated and the control groups. These proteins belong to several functional categories: amino acid metabolism, carbohydrate metabolism, cytoskeleton organization, regulatory processes, protein biosynthesis, and RNA processing. Thus, discovery proteomics provided deep data on novel aspects of plant stress biology. Our data hinted that protein accumulation stimulated seedlings' growth and affected the regulatory system, primarily through translation and RNA processing. Increased abundance of primary metabolism-related proteins points to more intensive metabolic processes triggered in germinating pea seeds upon X-ray exposure. The functional role of detected putative amyloidogenic proteins should be validated in overexpression or knockout follow-up studies.
2024-03-18 | PXD044798 | Pride
Project description:Long noncoding RNAs (lncRNAs) are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR) exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy) induced a significant change in the expression of many lncRNAs. The vast majority of lncRNAs identified to be differentially expressed after LDIR in either BALB/c or SPRET/EiJ had a significantly correlated expression pattern with at least one LDIR responsive mRNA. Functional analysis revealed that the response to LDIR in BALB/c mice is highly dynamic with enrichment for genes involved in tissue injury, inflammatory responses, and mammary gland development at 2, 4, and 8 weeks after LDIR, respectively. Our study demonstrates that genetic background strongly influences the expression of lncRNAs and their response to radiation and that lncRNAs may coordinate the tissue response to LDIR exposure via regulation of coding mRNAs.
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Project description:Ionizing radiation induces chronic metabolic oxidative stress and a mutator phenotype in hamster fibroblasts that is mediated by H(2)O(2), but the intracellular source of H(2)O(2) is not well defined. To determine the role of mitochondria in the radiation-induced mutator phenotype, end points of mitochondrial function were determined in unstable (CS-9 and LS-12) and stable (114) hamster fibroblast cell lines derived from GM10115 cells exposed to 10 Gy X rays. Cell lines isolated after irradiation demonstrated a 20-40% loss of mitochondrial membrane potential and an increase in mitochondrial content compared to the parental cell line GM10115. Surprisingly, no differences were observed in steady-state levels of ATP (P > 0.05). Unstable clones demonstrated increased oxygen consumption (two- to threefold; CS-9) and/or increased mitochondrial electron transport chain (ETC) complex II activity (twofold; LS-12). Using Western blot analysis and Blue Native gel electrophoresis, a significant increase in complex II subunit B protein levels was observed in LS-12 cells. Furthermore, immunoprecipitation assays revealed evidence of abnormal complex II assembly in LS-12 cells. Treatment of LS-12 cells with an inhibitor of ETC complex II (thenoyltrifluoroacetone) resulted in significant decreases in the steady-state levels of H(2)O(2) and a 50% reduction in mutation frequency as well as a 16% reduction in CAD gene amplification frequency. These data show that radiation-induced genomic instability was accompanied by evidence of mitochondrial dysfunction leading to increased steady-state levels of H(2)O(2) that contributed to increased mutation frequency and gene amplification. These results support the hypothesis that mitochondrial dysfunction originating from complex II can contribute to radiation-induced genomic instability by increasing steady-state levels of reactive oxygen species.
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Project description:Exposure to medium or high doses of ionizing radiation is a known risk factor for cancer in children. The extent to which low-dose radiation from natural sources contributes to the risk of childhood cancer remains unclear.In a nationwide census-based cohort study, we investigated whether the incidence of childhood cancer was associated with background radiation from terrestrial gamma and cosmic rays.Children < 16 years of age in the Swiss National Censuses in 1990 and 2000 were included. The follow-up period lasted until 2008, and incident cancer cases were identified from the Swiss Childhood Cancer Registry. A radiation model was used to predict dose rates from terrestrial and cosmic radiation at locations of residence. Cox regression models were used to assess associations between cancer risk and dose rates and cumulative dose since birth.Among 2,093,660 children included at census, 1,782 incident cases of cancer were identified including 530 with leukemia, 328 with lymphoma, and 423 with a tumor of the central nervous system (CNS). Hazard ratios for each millisievert increase in cumulative dose of external radiation were 1.03 (95% CI: 1.01, 1.05) for any cancer, 1.04 (95% CI: 1.00, 1.08) for leukemia, 1.01 (95% CI: 0.96, 1.05) for lymphoma, and 1.04 (95% CI: 1.00, 1.08) for CNS tumors. Adjustment for a range of potential confounders had little effect on the results.Our study suggests that background radiation may contribute to the risk of cancer in children, including leukemia and CNS tumors.
| S-EPMC4455589 | biostudies-literature
Project description:The effects of exposure to an environment where the background magnetic field (BMF) has been reduced were studied on wild-type Drosophila melanogaster by measuring its ability to survive a single exposure to ionizing radiation (IR) during its larval stage. The experimental design presented shows a timeframe, IR dose, and BMF parameters that will cause a significant and reproducible reduction of survival on this insect model. These results suggest that BMFs may play a fundamental role in the recovery or harm of a biological system that is exposed to single doses of IR.
| S-EPMC3426623 | biostudies-literature
Project description:Long noncoding RNAs (lncRNAs) are emerging as key regulators of diverse cell functions and processes. However, the relevance of lncRNAs in the cell and tissue response to ionizing radiation has not yet been characterized. Here we used microarray profiling to determine lncRNA and mRNA expression in mammary glands of BALB/c and SPRET/EiJ mice after low-dose ionizing radiation (LDIR) exposure. We found that unirradiated mammary tissues of these strains differed significantly in baseline expressions of 290 lncRNAs. LDIR exposure (10 cGy) induced a significant change in the expression of many lncRNAs. For BALB/c mice, a total of 357, 480, and 335 lncRNAs and 550, 911, and 389 coding RNAs were identified at 2, 4, and 8 weeks post-irradiation, respectively, while for SPRET/EiJ, a total of 327 lncRNAs and 424 mRNAs were identified at 4 weeks post-irradiation.
2014-12-01 | GSE62662 | GEO
Project description:Natural ionizing background radiation has exerted a constant pressure on organisms since the first forms of life appeared on Earth, so that cells have developed molecular mechanisms to avoid or repair damages caused directly by radiation or indirectly by radiation-induced reactive oxygen species (ROS). In the present study, we investigated the transcriptional effect of depriving Shewanella oneidensis cultures of background levels of radiation by growing the cells in a mine 655 m underground, thus reducing the dose rate from 72.1 to 0.9 nGy h-1 from control to treatment, respectively. RNASeq transcriptome analysis showed the differential expression of 4.6 and 7.6% of the S. oneidensis genome during early- and late-exponential phases of growth, respectively. The greatest change observed in the treatment was the downregulation of ribosomal proteins (21% of all annotated ribosomal protein genes during early- and 14% during late-exponential) and tRNA genes (14% of all annotated tRNA genes in early-exponential), indicating a marked decrease in protein translation. Other significant changes were the upregulation of membrane transporters, implying an increase in the traffic of substrates across the cell membrane, as well as the up and downregulation of genes related to respiration, which could be interpreted as a response to insufficient oxidants in the cells. In other reports, there is evidence in multiple species that some ROS not just lead to oxidative stress, but act as signaling molecules to control cellular metabolism at the transcriptional level. Consistent with these reports, several genes involved in the metabolism of carbon and biosynthesis of amino acids were also regulated, lending support to the idea of a wide metabolic response. Our results indicate that S. oneidensis is sensitive to the withdrawal of background levels of ionizing radiation and suggest that a transcriptional response is required to maintain homeostasis and retain normal growth.
| S-EPMC5955497 | biostudies-literature
Project description:Animal cells constantly receive information about and respond to environmental factors, including ionizing radiation. Although it is crucial for a cell to repair radiation-induced DNA damage to ensure survival, cellular responses to radiation exposure during early embryonic development remain unclear. In this study, we analyzed the effects of ionizing radiation in zebrafish embryos and found that radiation-induced ?H2AX foci formation and cell cycle arrest did not occur until the gastrula stage, despite the presence of major DNA repair-related gene transcripts, passed on as maternal factors. Interestingly, P21/WAF1 accumulation began ?6?h post-fertilization, although p21 mRNA was upregulated by irradiation at 2 or 4?h post-fertilization. These results suggest that the cellular responses of zebrafish embryos at 2 or 4?h post-fertilization to radiation failed to overcome P21 protein accumulation and further signaling. Regulation of P21/WAF1 protein stabilization appears to be a key factor in the response to genotoxins during early embryogenesis.
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Project description:Ionizing radiation, such as that emitted by uranium, may cause mutations and consequently lead to neoplasia in human cells. The TP53 gene acts to maintain genomic integrity and constitutes an important biomarker of susceptibility. The present study investigated the main alterations observed in exons 4, 5, 6, 7, and 8 of the TP53 gene and adjacent introns in Amazonian populations exposed to radioactivity. Samples were collected from 163 individuals. Occurrence of the following alterations was observed: (i) a missense exchange in exon 4 (Arg72Pro); (ii) 2 synonymous exchanges, 1 in exon 5 (His179His), and another in exon 6 (Arg213Arg); (iii) 4 intronic exchanges, 3 in intron 7 (C → T at position 13.436; C → T at position 13.491; T → G at position 13.511) and 1 in intron 8 (T → G at position 13.958). Alteration of codon 72 was found to be an important risk factor for cancer development (P = 0.024; OR = 6.48; CI: 1.29-32.64) when adjusted for age and smoking. Thus, TP53 gene may be an important biomarker for carcinogenesis susceptibility in human populations exposed to ionizing radiation.
| S-EPMC3613089 | biostudies-literature
Project description:Previous studies have found indications that exposure to ionising radiation (IR) results in DNA methylation changes in plants. However, this phenomenon is yet to be studied across multiple generations. Furthermore, the exact role of these changes in the IR-induced plant response is still far from understood. Here, we study the effect of gamma radiation on DNA methylation and its effect across generations in young Arabidopsis plants. A multigenerational set-up was used in which three generations (Parent, generation 1, and generation 2) of 7-day old Arabidopsis thaliana plants were exposed to either of the different radiation treatments (30, 60, 110, or 430 mGy/h) or to natural background radiation (control condition) for 14 days. The parental generation consisted of previously non-exposed plants, whereas generation 1 and generation 2 plants had already received a similar irradiation in the previous one or two generations, respectively. Directly after exposure the entire methylomes were analysed with UPLC-MS/MS to measure whole genome methylation levels. Whole genome bisulfite sequencing was used to identify differentially methylated regions (DMRs), including their methylation context in the three generations and this for three different radiation conditions (control, 30 mGy/h, and 110 mGy/h). Both intra- and intergenerational comparisons of the genes and transposable elements associated with the DMRs were made. Taking the methylation context into account, the highest number of changes were found for cytosines followed directly by guanine (CG methylation), whereas only limited changes in CHG methylation occurred and no changes in CHH methylation were observed. A clear increase in IR-induced DMRs was seen over the three generations that were exposed to the lowest dose rate, where generation 2 had a markedly higher number of DMRs than the previous two generations (Parent and generation 1). Counterintuitively, we did not see significant differences in the plants exposed to the highest dose rate. A large number of DMRs associated with transposable elements were found, the majority of them being hypermethylated, likely leading to more genetic stability. Next to that, a significant number of DMRs were associated with genes (either in their promoter-associated region or gene body). A functional analysis of these genes showed an enrichment for genes related to development as well as various stress responses, including DNA repair, RNA splicing, and (a)biotic stress responses. These observations indicate a role of DNA methylation in the regulation of these genes in response to IR exposure and shows a possible role for epigenetics in plant adaptation to IR over multiple generations.
| S-EPMC8044457 | biostudies-literature