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Drosophila melanogaster show a threshold effect in response to radiation.

ABSTRACT: We investigate the biological effects of radiation using adult Drosophila melanogaster as a model organism, focusing on gene expression and lifespan analysis to determine the effect of different radiation doses. Our results support a threshold effect in response to radiation: no effect on lifespan and no permanent effect on gene expression is seen at incident radiation levels below 100 J/kg. We also find that it is more appropriate to compare radiation effects in flies using the absorbed energy rather than incident radiation levels.

SUBMITTER: Antosh M

PROVIDER: S-EPMC4267449 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature

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Drosophila melanogaster show a threshold effect in response to radiation.

Antosh Michael M Fox David D Hasselbacher Thomas T Lanou Robert R Neretti Nicola N Cooper Leon N LN

Dose-response : a publication of International Hormesis Society 20140505 4

We investigate the biological effects of radiation using adult Drosophila melanogaster as a model organism, focusing on gene expression and lifespan analysis to determine the effect of different radiation doses. Our results support a threshold effect in response to radiation: no effect on lifespan and no permanent effect on gene expression is seen at incident radiation levels below 100 J/kg. We also find that it is more appropriate to compare radiation effects in flies using the absorbed energy ...[more]

PMID: 25552957

Similar Datasets

Drosophila melanogaster Show a Threshold Effect in Response to Radiation

2016-06-12 | GSE47999 | GEO

Drosophila melanogaster Show a Threshold Effect in Response to Radiation

Project description:We investigate the biological effects of radiation using Drosophila Melanogaster as a model organism, focusing on gene expression and lifespan analysis to determine the effect of different radiation doses. Our results support a threshold effect in response to radiation: no effect on lifespan and no permanent effect on gene expression is seen at doses below 10,000 Roentgens. Adult male Drosophila were irradiated 2 days after eclosion, with one of 6 radiation doses: 10; 1,000; 5,000; 10,000; 20,000 Roentgens. Samples were taken at 3 time points (2, 10 and 20 days post-irradiation).

2016-06-12 | E-GEOD-47999 | biostudies-arrayexpress

Deleterious mutations show increasing negative effects with age in Drosophila melanogaster.

Project description:BackgroundIn order for aging to evolve in response to a declining strength of selection with age, a genetic architecture that allows for mutations with age-specific effects on organismal performance is required. Our understanding of how selective effects of individual mutations are distributed across ages is however poor. Established evolutionary theories assume that mutations causing aging have negative late-life effects, coupled to either positive or neutral effects early in life. New theory now suggests evolution of aging may also result from deleterious mutations with increasing negative effects with age, a possibility that has not yet been empirically explored.ResultsTo directly test how the effects of deleterious mutations are distributed across ages, we separately measure age-specific effects on fecundity for each of 20 mutations in Drosophila melanogaster. We find that deleterious mutations in general have a negative effect that increases with age and that the rate of increase depends on how deleterious a mutation is early in life.ConclusionsOur findings suggest that aging does not exclusively depend on genetic variants assumed by the established evolutionary theories of aging. Instead, aging can result from deleterious mutations with negative effects that amplify with age. If increasing negative effect with age is a general property of deleterious mutations, the proportion of mutations with the capacity to contribute towards aging may be considerably larger than previously believed.

| S-EPMC7526172 | biostudies-literature

Marine plankton show threshold extinction response to Neogene climate change.

Project description:Ongoing climate change is predicted to trigger major shifts in the geographic distribution of marine plankton species. However, it remains unclear whether species will successfully track optimal habitats to new regions, or face extinction. Here we show that one significant zooplankton group, the radiolaria, underwent a severe decline in high latitude species richness presaged by ecologic reorganization during the late Neogene, a time of amplified polar cooling. We find that the majority (71%) of affected species did not relocate to the warmer low latitudes, but went extinct. This indicates that some plankton species cannot track optimal temperatures on a global scale as assumed by ecologic models; instead, assemblages undergo restructuring and extinction once local environmental thresholds are exceeded. This pattern forewarns profound diversity loss of high latitude radiolaria in the near future, which may have cascading effects on the ocean food web and carbon cycle.

| S-EPMC7582175 | biostudies-literature

Genome-wide association analysis of radiation resistance in Drosophila melanogaster.

Project description:BackgroundIonizing radiation is genotoxic to cells. Healthy tissue toxicity in patients and radiation resistance in tumors present common clinical challenges in delivering effective radiation therapies. Radiation response is a complex, polygenic trait with unknown genetic determinants. The Drosophila Genetic Reference Panel (DGRP) provides a model to investigate the genetics of natural variation for sensitivity to radiation.Methods and findingsRadiation response was quantified in 154 inbred DGRP lines, among which 92 radiosensitive lines and 62 radioresistant lines were classified as controls and cases, respectively. A case-control genome-wide association screen for radioresistance was performed. There are 32 single nucleotide polymorphisms (SNPs) associated with radio resistance at a nominal p<10(-5); all had modest effect sizes and were common variants with the minor allele frequency >5%. All the genes implicated by those SNP hits were novel, many without a known role in radiation resistance and some with unknown function. Variants in known DNA damage and repair genes associated with radiation response were below the significance threshold of p<10(-5) and were not present among the significant hits. No SNP met the genome-wide significance threshold (p = 1.49 × 10(-7)), indicating a necessity for a larger sample size.ConclusionsSeveral genes not previously associated with variation in radiation resistance were identified. These genes, especially the ones with human homologs, form the basis for exploring new pathways involved in radiation resistance in novel functional studies. An improved DGRP model with a sample size of at least 265 lines and ideally up to 793 lines is recommended for future studies of complex traits.

| S-EPMC4133248 | biostudies-literature

Recent selective sweeps in North American Drosophila melanogaster show signatures of soft sweeps.

Project description:Adaptation from standing genetic variation or recurrent de novo mutation in large populations should commonly generate soft rather than hard selective sweeps. In contrast to a hard selective sweep, in which a single adaptive haplotype rises to high population frequency, in a soft selective sweep multiple adaptive haplotypes sweep through the population simultaneously, producing distinct patterns of genetic variation in the vicinity of the adaptive site. Current statistical methods were expressly designed to detect hard sweeps and most lack power to detect soft sweeps. This is particularly unfortunate for the study of adaptation in species such as Drosophila melanogaster, where all three confirmed cases of recent adaptation resulted in soft selective sweeps and where there is evidence that the effective population size relevant for recent and strong adaptation is large enough to generate soft sweeps even when adaptation requires mutation at a specific single site at a locus. Here, we develop a statistical test based on a measure of haplotype homozygosity (H12) that is capable of detecting both hard and soft sweeps with similar power. We use H12 to identify multiple genomic regions that have undergone recent and strong adaptation in a large population sample of fully sequenced Drosophila melanogaster strains from the Drosophila Genetic Reference Panel (DGRP). Visual inspection of the top 50 candidates reveals that in all cases multiple haplotypes are present at high frequencies, consistent with signatures of soft sweeps. We further develop a second haplotype homozygosity statistic (H2/H1) that, in combination with H12, is capable of differentiating hard from soft sweeps. Surprisingly, we find that the H12 and H2/H1 values for all top 50 peaks are much more easily generated by soft rather than hard sweeps. We discuss the implications of these results for the study of adaptation in Drosophila and in species with large census population sizes.

| S-EPMC4338236 | biostudies-literature

Indigenous microbial communities in heavy oil show a threshold response to salinity.

Project description:Microbial degradation influences the quality of oil resources. The environmental factors that shape the composition of oil microbial communities are largely unknown because most samples from oil fields are impacted by anthropogenic oil production, perturbing the native ecosystem with exogenous fluids and microorganisms. We investigated the relationship between formation water geochemistry and microbial community composition in undisturbed oil samples. We isolated 43 microliter-sized water droplets naturally enclosed in the heavy oil of the Pitch Lake, Trinidad and Tobago. The water chemistry and microbial community composition within the same water droplet were determined by ion chromatography and 16S rRNA gene amplicon sequencing, respectively. The results revealed a high variability in ion concentrations and community composition between water droplets. Microbial community composition was mostly affected by the chloride concentration, which ranged from freshwater to brackish-sea water. Remarkably, microbial communities did not respond gradually to increasing chloride concentration but showed a sudden change to less diverse and uneven communities when exceeding a chloride concentration of 57.3 mM. The results reveal a threshold-regulated response of microbial communities to salinity, offering new insights into the microbial ecology of oil reservoirs.

| S-EPMC8684454 | biostudies-literature

Transcriptional response to dietary restriction in Drosophila melanogaster.

Project description:Dietary restriction (DR) extends lifespan in a wide variety of organisms. Although several genes and pathways associated with this longevity response have been identified, the specific mechanism through which DR extends lifespan is not fully understood. We have recently developed a novel methodology to screen for transcriptional changes in response to acutely imposed DR upon adult Drosophila melanogaster and identified groups of genes that switch their transcriptional patterns from a normal diet pattern to a restricted diet pattern, or 'switching genes'. In this current report we extend our transcriptional data analysis with gene set enrichment analysis to generate a pathway-centered perspective. The pattern of temporal behavior in response to the diet switch is strikingly similar within and across pathways associated with mRNA processing and protein translation. Furthermore, most genes within these pathways display an initial spike in activity within 6-8h from the diet switch, followed by a coordinated, partial down-regulation after 24h. We propose this represents a stereotypical response to DR, which ultimately leads to a mild but widespread inhibition of transcriptional and translational activity. Inhibition of the protein synthesis pathway has been observed in DR in other studies and has been shown to extend lifespan in several model organisms.

| S-EPMC4177363 | biostudies-literature

Transcriptional response to alcohol exposure in Drosophila melanogaster.

Project description:BackgroundAlcoholism presents widespread social and human health problems. Alcohol sensitivity, the development of tolerance to alcohol and susceptibility to addiction vary in the population. Genetic factors that predispose to alcoholism remain largely unknown due to extensive genetic and environmental variation in human populations. Drosophila, however, allows studies on genetically identical individuals in controlled environments. Although addiction to alcohol has not been demonstrated in Drosophila, flies show responses to alcohol exposure that resemble human intoxication, including hyperactivity, loss of postural control, sedation, and exposure-dependent development of tolerance.ResultsWe assessed whole-genome transcriptional responses following alcohol exposure and demonstrate immediate down-regulation of genes affecting olfaction, rapid upregulation of biotransformation enzymes and, concomitant with development of tolerance, altered transcription of transcriptional regulators, proteases and metabolic enzymes, including biotransformation enzymes and enzymes associated with fatty acid biosynthesis. Functional tests of P-element disrupted alleles corresponding to genes with altered transcription implicated 75% of these in the response to alcohol, two-thirds of which have human orthologues.ConclusionExpression microarray analysis is an efficient method for identifying candidate genes affecting complex behavioral and physiological traits, including alcohol abuse. Drosophila provides a valuable genetic model for comparative genomic analysis, which can inform subsequent studies in human populations. Transcriptional analyses following alcohol exposure in Drosophila implicate biotransformation pathways, transcriptional regulators, proteolysis and enzymes that act as metabolic switches in the regulation of fatty acid metabolism as important targets for future studies of the physiological consequences of human alcohol abuse.

| S-EPMC1794562 | biostudies-literature

A comparison of the transcriptome of Drosophila melanogaster in response to entomopathogenic fungus, ionizing radiation, starvation and cold shock.

Project description:BackgroundThe molecular mechanisms that determine the organism's response to a variety of doses and modalities of stress factors are not well understood.ResultsWe studied effects of ionizing radiation (144, 360 and 864 Gy), entomopathogenic fungus (10 and 100 CFU), starvation (16 h), and cold shock (+4, 0 and -4°C) on an organism's viability indicators (survival and locomotor activity) and transcriptome changes in the Drosophila melanogaster model. All stress factors but cold shock resulted in a decrease of lifespan proportional to the dose of treatment. However, stress-factors affected locomotor activity without correlation with lifespan. Our data revealed both significant similarities and differences in differential gene expression and the activity of biological processes under the influence of stress factors.ConclusionsStudied doses of stress treatments deleteriously affect the organism's viability and lead to different changes of both general and specific cellular stress response mechanisms.

| S-EPMC4686790 | biostudies-literature

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