Genetic variation in parthenogenetic collembolans is associated with differences in fitness and cadmium-induced transcriptome responses
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ABSTRACT:
ORGANISM(S): Folsomia candida
PROVIDER: GSE34167 | GEO | 2012/12/21
SECONDARY ACCESSION(S): PRJNA149715
REPOSITORIES: GEO
Similar Datasets
Project description:Ecotoxicological tests may be biased by the use of laboratory strains that usually contain very limited genetic diversity. It is therefore essential to study how genetic variation influences stress tolerance relevant for toxicity outcomes. To that end we studied sensitivity to cadmium in two distinct genotypes of the parthogenetic soil ecotoxicological model organism Folsomia candida. Clonal lines of both genotypes (TO1 and TO2) showed divergent fitness responses to cadmium exposure; TO2 reproduction was 20% less affected by cadmium. Statistical analyses revealed significant differences between the cadmium-affected transcriptomes; i) the number of genes affected by cadmium in TO2 was only minor (~22%) compared to TO1; ii) 97 genes showed a genotype M-CM-^W cadmium interaction and their response to cadmium showed globally larger fold changes in TO1 when compared to TO2; iii) the interaction genes showed a concerted manner of expression in TO1 while a less coordinated pattern was observed in TO2. We conclude that (1) there is genetic variation in parthenogenetic populations of F. candida, and (2) this variation affects life-history and molecular endpoints relative to cadmium toxicity. This sheds new light on the sources of biological variability in test results, even when the test organisms are thought to be genetically homogeneous because of their parthenogenetic reproduction. Gene expression was measured in two different clones (TO1 and TO2) of the springtail Folsomia candida, after exposure of 2 days to soil containing cadmium (Cd+) and non-spiked (Cd-) soil. A 2 x 2 factorial analysis was performed, to examine the effect of clone (TO1, TO2), of treatment (Cd+, Cd-), and the clone x treatment interaction.
2012-12-21 | E-GEOD-34167 | biostudies-arrayexpress
Project description:Diclofenac is widely used as nonsteroidal anti-inflammatory drug leaving residues in the environment. To investigate effects on terrestrial ecosystems, we measured dissipation rate in soil and investigated ecotoxicological and transcriptome-wide responses in Folsomia candida. Exposure for 4 weeks to diclofenac reduced both survival and reproduction of F. candida in a dose-dependent manner. At concentrations ≥200 mg/kg soil diclofenac remained stable in the soil during a 21-day incubation period. Microarrays examined transcriptional changes at low and high diclofenac exposure concentrations. The results indicated that development and growth were severely hampered and immunity-related genes, mainly directed against bacteria and fungi, were significantly up-regulated. Furthermore, neural metabolic processes were significantly affected only at the high concentration. We conclude that diclofenac is toxic to non-target soil invertebrates, although its mode of action is different from the mammalian toxicity. The genetic markers proposed in this study may be promising early markers for diclofenac ecotoxicity.
2014-10-01 | GSE59589 | GEO
Project description:Cadmium is a natural element that can accumulate to toxic levels in the environment leading to detrimental effects in animals and humans including kidney, liver and lung injuries. Using a transcriptomics approach, genes and cellular pathways affected by a low dose of cadmium were investigated. Adult largemouth bass were intraperitoneally injected with 20 µg/kg of cadmium chloride and microarray analyses were conducted in the liver and testis 48 hours after injection. Transcriptomics profiles identified in response to cadmium treatment were tissue-specific with the most differential expression changes found in the liver tissues, which also contained much higher levels of cadmium than the testes. Acute exposure to a low dose of cadmium induced oxidative stress response and oxidative damage pathways in the liver. The mRNA levels of antioxidants such as catalase increased and numerous transcripts related to DNA damage and DNA repair were significantly altered. Hepatic mRNA levels of metallothionein, a proposed marker of cadmium exposure, showed a small insignificant increase after 48 hours exposure. Carbohydrate metabolic pathways were also disrupted in cadmium-exposed fish with hepatic transcripts such as UDP-glucose pyrophosphorylase 2 and sorbitol dehydrogenase highly induced. Both tissues exhibited a disruption of steroid signalling pathways. In the testis, estrogen receptor beta and transcripts linked to cholesterol metabolism were suppressed. On the contrary, genes involved in cholesterol metabolism were highly increased in the liver including genes encoding for the rate limiting steroidogenic acute regulatory protein and the catalytic enzyme 7-dehydrocholesterol reductase. Integration of the transcriptomics data using functional enrichment analyses revealed a number of enriched gene networks associated with previously reported adverse outcomes of cadmium exposure such as liver toxicity and impaired reproduction. Adult largemouth bass (n=4 per treatment) were ip injected with a single dose of cadmium chloride (20 ug/kg) or a saline solution. After 48 hours, liver and testis were excised and differential gene expression profiles were examined.
2014-04-02 | E-GEOD-53047 | biostudies-arrayexpress
Project description:Metal ecotoxicity on soil organisms, e.g. in Enchytraeids (also known as potworms), has been addressed mainly by assessing effects on survival and reproduction but very little is known about the molecular underlying mechanisms of responses. The main purpose of the present study was to assess and compare the transcriptional responses of Enchytraeus albidus to an essential (zinc) and a non-essential metal (cadmium). Exposure was performed to two concentrations of known effect on reproduction (EC50, EC90) at three time periods (2, 4 and 8 days). Results showed that transcriptional responses were influenced by exposure duration but, independently of that, the mechanisms of response to Cd and Zn were consistently different. Both metals affected pathways related with the regulation of gene expression, calcium homeostasis and cellular respiration. Mechanisms of toxicity that were exclusively associated with Cd exposures were the inhibition of DNA repair and the impairment of ubiquitin-mediated proteolysis. The microarray for E. albidus was a useful tool to detect molecular pathways affected by metal exposures. Transcriptional responses strongly correlated with known mechanisms of Cd and Zn responses in other organisms, suggesting cross-species conserved mechanisms of action. It should be highlighted that we could not only retrieve mechanistic information, but also that genes responded within 2-8 days of exposure. This represents an additional advantage of using such molecular endpoints as a complement to the traditional, more time-consuming endpoints. Gene expression in E.albidus was measured at 2, 4, and 8 days after exposure to Cadmium and Zinc at 2 concentrations of effect on reprocduction (EC50 and EC90). Three biological replicates per exposure treatment in each time point and 4 biological replicates of control conditions were used.
2012-06-30 | E-GEOD-33944 | biostudies-arrayexpress
Project description:This study examined how transcriptomics tools can be included in a Triad-based soil quality assessment to assess the toxicity of soils from river banks polluted by metals. To that end we measured chemical soil properties and used the standardized ISO guideline for ecotoxicological tests and a newly developed microarray for gene expression in the indicator soil arthropod, Folsomia candida. Microarray analysis revealed that the oxidative stress response pathway was significantly affected in all soils except one. The data indicate that changes in cell redox homeostasis are a significant signature of metal stress. Finally, 32 genes showed significant dose-dependent expression with metal concentrations. They are promising genetic markers providing an early indication of the need for higher tier testing in soil quality. One of the least polluted soils showed toxicity in the bioassay that could be removed by sterilization. The gene expression profile for this soil did not show a metal-related signature, confirming that another factor than metals (most likely of biological origin) caused the toxicity. This study demonstrates the feasibility and advantages of integrating transcriptomics into Triad-based soil quality assessment. Combining molecular and organismal life-history traitM-bM-^@M-^Ys stress responses helps identifying causes of adverse effect in bioassays. Further validation is needed for verifying the set of genes with dose-dependent expression patterns linked with toxic stress. We used a one-color microarray design where each sample was hybridized to a single array
2014-02-01 | E-GEOD-52393 | biostudies-arrayexpress
Project description:Cadmium is a natural element that can accumulate to toxic levels in the environment leading to detrimental effects in animals and humans including kidney, liver and lung injuries. Using a transcriptomics approach, genes and cellular pathways affected by a low dose of cadmium were investigated. Adult largemouth bass were intraperitoneally injected with 20 µg/kg of cadmium chloride and microarray analyses were conducted in the liver and testis 48 hours after injection. Transcriptomics profiles identified in response to cadmium treatment were tissue-specific with the most differential expression changes found in the liver tissues, which also contained much higher levels of cadmium than the testes. Acute exposure to a low dose of cadmium induced oxidative stress response and oxidative damage pathways in the liver. The mRNA levels of antioxidants such as catalase increased and numerous transcripts related to DNA damage and DNA repair were significantly altered. Hepatic mRNA levels of metallothionein, a proposed marker of cadmium exposure, showed a small insignificant increase after 48 hours exposure. Carbohydrate metabolic pathways were also disrupted in cadmium-exposed fish with hepatic transcripts such as UDP-glucose pyrophosphorylase 2 and sorbitol dehydrogenase highly induced. Both tissues exhibited a disruption of steroid signalling pathways. In the testis, estrogen receptor beta and transcripts linked to cholesterol metabolism were suppressed. On the contrary, genes involved in cholesterol metabolism were highly increased in the liver including genes encoding for the rate limiting steroidogenic acute regulatory protein and the catalytic enzyme 7-dehydrocholesterol reductase. Integration of the transcriptomics data using functional enrichment analyses revealed a number of enriched gene networks associated with previously reported adverse outcomes of cadmium exposure such as liver toxicity and impaired reproduction.
2014-04-02 | GSE53047 | GEO
Project description:Bioassay is a system for monitoring toxicity of chemicals in the environment via the biological responses of experimental organisms. These responses can be detected by analysis of genome-wide changes in mRNA expression levels using DNA microarray. We applied this system for evaluation of synergistic toxicity by cadmium and thiuram, as this combination showed mutual growth inhibition in yeast. Hierarchical cluster analysis using the mRNA expression profiles suggested the response of yeast to this combination is similar to that seen with cadmium treatment. Functional characterization of induced genes by this combination treatment also suggests the enhanced toxicity of cadmium. This toxicity was observed as the damage to mitochondrial functions which were not observed with either cadmium or thiuram treatments alone. The potential toxicity to mitochondria by this combinational treatment was confirmed as the result of mitochondrial curing. We could evaluate the synergistic toxicity by cadmium and thiuram and show the possible use of transcriptome bioassay for synergistic toxicity. Keywords: stress response
2007-09-01 | GSE8718 | GEO
Project description:Metals at high concentrations can exert toxic effects on microorganisms. It has been widely reported that lowering environmental pH reduces effects of cadmium toxicity in bacteria. Understanding the effects of pH-mediated cadmium toxicity on bacteria would be useful for minimizing cadmium toxicity in the environment and gaining insight into the interactions between organic and inorganic components of life. Growth curve analysis confirmed that cadmium was less toxic to Escherichia coli at pH 5 than at pH 7 in M9 minimal salts medium. To better understand the cellular mechanisms by which lowering pH decreases cadmium toxicity, we used DNA microarrays to characterize global gene expression patterns in E. coli in response to cadmium exposure at moderately acidic (5) and neutral (7) values of pH. Higher expression of several stress response genes including hdeA, otsA, and yjbJ at pH 5 after only 5 minutes was observed and may suggest that acidic pH more rapidly induces genes that confer cadmium resistance. Genes involved in transport were more highly expressed at pH 7 than at pH 5 in the presence of cadmium. Of the genes that showed an interaction between pH and cadmium effects, 46% encoded hypothetical proteins, which may have novel functions involved in mitigating cadmium toxicity.
2008-08-21 | GSE12373 | GEO
Project description:This study examined how transcriptomics tools can be included in a Triad-based soil quality assessment to assess the toxicity of soils from river banks polluted by metals. To that end we measured chemical soil properties and used the standardized ISO guideline for ecotoxicological tests and a newly developed microarray for gene expression in the indicator soil arthropod, Folsomia candida. Microarray analysis revealed that the oxidative stress response pathway was significantly affected in all soils except one. The data indicate that changes in cell redox homeostasis are a significant signature of metal stress. Finally, 32 genes showed significant dose-dependent expression with metal concentrations. They are promising genetic markers providing an early indication of the need for higher tier testing in soil quality. One of the least polluted soils showed toxicity in the bioassay that could be removed by sterilization. The gene expression profile for this soil did not show a metal-related signature, confirming that another factor than metals (most likely of biological origin) caused the toxicity. This study demonstrates the feasibility and advantages of integrating transcriptomics into Triad-based soil quality assessment. Combining molecular and organismal life-history trait’s stress responses helps identifying causes of adverse effect in bioassays. Further validation is needed for verifying the set of genes with dose-dependent expression patterns linked with toxic stress.
2014-02-01 | GSE52393 | GEO
Project description:Polycyclic aromatic hydrocarbons are common pollutants in soil, have negative effects on soil ecosystems, and are potentially carcinogenic. The Springtail (Collembola) Folsomia candida is often used as an indicator species for soil toxicity. Here we report a toxicogenomic study that translates the ecological effects of the polycyclic aromatic hydrocarbon phenanthrene in soil to the early transcriptomic responses in Folsomia candida. Microarrays were used to examine two different exposure concentrations of phenanthrene, namely the EC10 (24.95 mg kg-1 soil) and EC50 (45.80 mg kg-1 soil) on reproduction of this springtail, which evoked 405 and 251 differentially expressed transcripts, respectively. Fifty transcripts were differential in response to either concentration. Many transcripts encoding xenobiotic detoxification and biotransformation enzymes (phases I, II, and III) were upregulated in response to either concentration. Furthermore, indications of general and oxidative stress were found in response to phenanthrene. Chitin metabolism appeared to be disrupted particularly at the low concentration, and protein translation appeared suppressed at the high concentration of phenanthrene; most likely in order to reallocate energy budgets for the detoxification process. Finally, an immune response was evoked especially in response to the high effect concentration, which was also described in a previous transcriptomic study using the same effect concentration (EC50) of cadmium. Our study provides new insights in the molecular mode of action of the important polluting class of polycyclic aromatic hydrocarbons in soil animals. Furthermore, we present a fast, sensitive, and specific soil toxicity test which enhances traditional tests and may help to improve current environmental risk assessments and monitoring of potentially polluted sites. Folsomia candida was exposed to phenanthrene spiked soil or untreated (reference/control) soil for 2 days. Two different concentrations of phenanthrene were used, 24.95 and 45.80 mg/kg soil which represent the EC10 and EC50 on reproduction, respectively. For each concentration treatment 4 biological replicates were used, replicate samples consisted of total RNA extracted from ~30 animals exposed in the same jar to either reference or phenanthrene spiked soil. Phenanthrene treated samples were always hybridized to reference samples in an evenly distributed dye-swap manner, which resulted in total in 8 hybridizations of 16 samples.
2010-05-18 | E-GEOD-14207 | biostudies-arrayexpress