Project description:We compared the transcriptomic response to UVC radiation in widltype (N2), DNA repair-deficient (xpa-1), and germ cell-deficient (glp-1) young adult nematodes. We were interested in the wildtype response to this stressor, and postulated that the early (3h post-exposure) difference might be different in nucleotide excision repair-deficient (xpa-1) nematodes. We also hypothesized that the response would be different in young adults composed entirely of somatic cells (glp-1 strain at this temperature), compared to germ cell-bearing and gravid young adults (N2 and xpa-1). Finally, we compared constitutive differences in gene expression between the strains.
Project description:Ultraviolet C radiation (UVC) damages the nuclear and mitochondrial genomes; this damage is repaired in the nuclear but not mitochondrial genome. Ethidium bromide (EtBr) inhibits mitochondrial DNA replication. We were interested in the transcriptomic response to exposure to UVC, EtBr, and the combination. The UVC exposure protocol results in a high level of mitochondrial DNA damage, and a low level of nuclear DNA damage (because of repair). We exposed age-matched L1-stage Caenorhabditis elegans to ultraviolet C radiation (UVC ) three times, separated in time by 24 h, in the absence of food. After the third exposure, larvae were placed on K agar plates with OP50 bacterial food. In some cases ethidium bromide was also used. Nematodes were sampled for RNA isolation several times.
Project description:N2 young adult animals were analyzed four hours after exposure to wild-type Candida albicans DAY185, heat-killed C. albicans DAY185 and heat-killed Escherichia coli OP50, all on Brain Heart Infusion (BHI) agar. It was necessary to use heat-killed E. coli OP50 as a control for these experiments because live E. coli OP50 (the normal nematode food source) is pathogenic to nematodes on BHI agar. These data identify the C. elegans genes that are differentially regulated during nematode infection with a human fungal pathogen.
Project description:Ultraviolet C radiation (UVC) damages the nuclear and mitochondrial genomes; this damage is repaired in the nuclear but not mitochondrial genome. Ethidium bromide (EtBr) inhibits mitochondrial DNA replication. We were interested in the transcriptomic response to exposure to UVC, EtBr, and the combination. The UVC exposure protocol results in a high level of mitochondrial DNA damage, and a low level of nuclear DNA damage (because of repair).
Project description:In the current study a systematic investigation of life stage, tissue and cell dependent sensitivity to ionizing radiation in the nematode Caenorhabditis elegans was conducted. This revealed that individuals that have reached the post-mitotic L4 stage showed no significant effects with respect to mortality, morbidity or reproduction when subjected to either acute dose ≤6 Gy(1500 mGy/h) or chronic exposure ≤4 Gy( ≤ 100 mGy/h). In contrast, chronic exposure from embryo to young adult stage caused a dose and dose rate dependent reprotoxicitiy with 43% reduction in total brood size at 6.7Gy (107 mGy/h). Systematic targeted irradiation of developmental stages showed that exposure during L1 to young L4 was sufficient to induce reprotoxic effects. Exposure during these stages was associated with a dose rate dependent genotoxic effects on gonads with 1.7 to 3.2 fold increase in germ cell apoptosis in larvae subjected to 40-100 mGy/h, respectively. Importantly, exposure to gamma radiation significantly impaired spermatogenesis in a dose rate dependent manner. The observed reduction in the number of spermatids accounted for xx% of the reprotoxic effects, thus signifying spermatids as the most radiosensitive cell type in C. elegans. Molecular responses analyzed by RNAseq of nematodes irradiated from L1 to L4 stage revealed a significant enrichment of genes related to both male and hermaphrodite reproductive processes. Gene network analysis identified adverse genotoxic effects related to down-regulation of genes required for spindle formation and sperm meiosis/maturation, including smz-1, smz-2 and htas-1. The expression of a subset of 28 set-17 regulated Major Sperm Proteins (MSP) required for spermatids production was correlated to the reduction in reproduction and the number of spermatids, thus corroborating the impairment of spermatogenesis as the major cause of gamma radiation induced life-stage dependent reprotoxic effect. Furthermore, the progeny of irradiated nematodes showed significant embryonal DNA damage that was associated with persistent effect on somatic growth. Unexpectedly, these nematodes did however maintain much of their reproductive capacity in spite of the reduced growth.
Project description:we used short-reads to perform a comparative analysis S. carpocapsae ALL strain IJs and young adults and C.elegans dauer strain N2 and young adult strain him-8.
Project description:Spirosoma montaniterrae DY10T is an uncharacterized radiation-resistanct bacteria isolated from soil in South Korea. In order to identify the underlying mechanisms involved in UVC-resistance, we generated time-series transcriptome data with UVC radiation and analyzed data with computational methods.
Project description:DNA damage caused by UV radiation initiates cellular recovery mechanisms, which involve activation of DNA damage response pathways, cell cycle arrest and apoptosis. To assess cellular transcriptional responses to UVC-induced DNA damage we compared time course responses of human skin fibroblasts to low and high doses of UVC radiation known to induce a transient cellular replicative arrest or apoptosis, respectively. UVC radiation elicited >3-fold changes in 460 out of 12,000 transcripts and 89% of these represented downregulated transcripts. Only 5% of the regulated genes were common to both low and high doses of radiation. Cells inflicted with a low dose of UVC exhibited transcription profiles demonstrating transient regulation followed by recovery, whereas the responses were persistent after the high dose. A detailed clustering analysis and functional classification of the targets implied regulation of biologically divergent responses and suggested involvement of transcriptional and translational machinery, inflammatory, anti-proliferative and anti-angiogenic responses. The data support the notion that UVC radiation induces prominent, dose-dependent downregulation of transcription. However, the data strongly suggest that transcriptional repression is also target gene selective. Furthermore, the results demonstrate that dose-dependent induction of cell cycle arrest and apoptosis by UVC radiation are transcriptionally highly distinct responses. Keywords: other
Project description:Significant impacts on gene expression were observed generations after exposure in ionising radiation exposed nematodes. C. elegans were exposed to 1 Gy of X-rays and their gene expression was analysed several generations later with whole genome oligoarrays (Washington University).