Daphnia magna
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA93371 | ENA |
REPOSITORIES: ENA
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Project description:Toxic chemical contaminants have variety of detrimental effects on various species and the impact of pollutants on ecosystems has become an urgent issue. However, very limited species have been examined to date and those studies are mainly limited to vertebrates. In this study, we aimed to establish an ecotoxicogenomic bases for Daphnia magna. Based on a daphnia EST database, we made oligonucleotide-based DNA microarray that has high reproducibility. The DNA microarray was applied to evaluate gene expression profiles of daphnid exposed to chemicals. Characteristic gene expression patterns depending on chemicals indicate that the Daphnia microarray can be used for mechanistic understanding of chemical toxicity. Although acute toxicity test or reproductive toxicity test can provide hazardous concentrations of chemicals, they give no information about mode of action. Our study can be a breakthrough for the evaluation of chemical toxicity on environmental organisms. Keywords: Chemical response
2005-12-31 | GSE3445 | GEO
Project description:Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxicology has presented new avenues to develop exposure biomarkers and investigate the mode of toxicity of novel chemicals. In the present study we used a 15k oligonucleotide microarray for Daphnia magna, a freshwater crustacean and common indicator species for toxicity, to differentiate between particle specific and ionic silver toxicity and to develop exposure biomarkers for citrate-coated and PVP-coated AgNPs. Gene expression profiles revealed that AgNO3 and AgNPs have distinct expression profiles suggesting different modes of toxicity. However, the gene expression profiles of the different coated AgNPs were similar revealing similarities in the cellular effects of these two particles. Major biological processes disrupted by the AgNPs include protein metabolism and signal transduction. In contrast, AgNO3 caused a downregulation of developmental processes, particularly in sensory development. Metal responsive and DNA damage repair genes were induced by the PVP AgNPs, but not the other treatments. In addition, two specific biomarkers were developed for the environmental detection of PVP AgNPs; although further verification under different environmental conditions is needed. We exposed Daphnia magna to the 1/10 LC50 and LC25 of citrate coated and PVP-coated Ag nanoparticles and Ag+ as AgNO3 for 24-h. For each exposure condition, we performed 6 replicate exposures with 5 individuals in each. All exposures were compared to a unexposed laboratory control.
2012-08-04 | E-GEOD-35150 | biostudies-arrayexpress
Project description:For most chemicals, environmental toxicity is only investigated for a single generation. In this study we investigate the effect of the fungicide prochloraz across generations in Daphnia magna. The study design included two exposure scenarios; one where all three generations were continuously exposed to prochloraz (100 ug/L) and one where only the first generation (F0) was exposed. We studied effects at different levels of biological organization combining key phenotypic effects, such as growth and reproduction, CYP enzyme activity, metabolomics and for generation F2 also transcriptomics
2020-12-01 | E-MTAB-9309 | biostudies-arrayexpress
Project description:Daphnia magna is a bio-indicator organism accepted by several international water quality regulatory agencies. Current approaches for assessment of water quality rely on acute and chronic toxicity that provide no insight into the cause of toxicity. Recently, molecular approaches, such as genome wide gene expression responses, are enabling an alternative mechanism based approach to toxicity assessment. While these genomic methods are providing important mechanistic insight into toxicity, statistically robust prediction systems that allow the identification of chemical contaminants from the molecular response to exposure are needed. Here we apply advanced machine learning approaches to develop predictive models of contaminant exposure using a D. magna gene expression dataset for 36 chemical exposures. We demonstrate here that we can discriminate between chemicals belonging to different chemical classes including endocrine disruptors, metals and industrial chemicals based on gene expression. We also show that predictive models based on indices of whole pathway transcriptional activity can achieve comparable results while facilitating biological interpretability. D. magna were exposed to 36 Chemicals and 5 control series in quadruplicate.
2013-01-17 | E-GEOD-43564 | biostudies-arrayexpress
Project description:There is still a lot of contradiction on whether metal ions are solely responsible for the observed the toxicity of ZnO and CuO nanoparticles to aquatic species. While most tests have studied nanoparticle effects at organismal levels (e.g. mortality, reproduction), effects at suborganismal levels may clarify the role of metal ions, nanoparticles and nanoparticle aggregates. In this study, the effect of ZnO, CuO nanoparticles and zinc, copper salts was tested on the gene expression levels in Daphnia magna. D. magna was exposed during 96 hours to 10% immobilization concentrations of all chemicals, after which daphnids were sampled for a differential gene expression analysis using microarray. When comparing the nanoparticle exposed daphnids (ZnO or CuO) to the metal salt exposed daphnids (zinc or copper salt), the microarray results showed no significantly differentially expressed genes. These results indicate that the toxicity of the tested ZnO and CuO nanoparticles to D. magna caused is solely caused by toxic metal ions.
2014-03-01 | GSE54738 | GEO
Project description:There is still a lot of contradiction on whether metal ions are solely responsible for the observed the toxicity of ZnO and CuO nanoparticles to aquatic species. While most tests have studied nanoparticle effects at organismal levels (e.g. mortality, reproduction), effects at suborganismal levels may clarify the role of metal ions, nanoparticles and nanoparticle aggregates. In this study, the effect of ZnO, CuO nanoparticles and zinc, copper salts was tested on the gene expression levels in Daphnia magna. D. magna was exposed during 96 hours to 10% immobilization concentrations of all chemicals, after which daphnids were sampled for a differential gene expression analysis using microarray. When comparing the nanoparticle exposed daphnids (ZnO or CuO) to the metal salt exposed daphnids (zinc or copper salt), the microarray results showed no significantly differentially expressed genes. These results indicate that the toxicity of the tested ZnO and CuO nanoparticles to D. magna caused is solely caused by toxic metal ions.
2014-03-01 | GSE54736 | GEO
Project description:Daphnia magna has been used extensively to evaluate organism- and population-level responses to pollutants in acute toxicity and reproductive toxicity tests. We have previously reported that exposure to juvenile hormone (JH) agonists results in a reduction of reproductive function and production of male offspring in a cyclic parthenogenesis, D. magna. Recent advances in molecular techniques have provided tools to better understand the responses to pollutants in aquatic organisms including D. magna. DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to JH agonists; methoprene (125, 250 and 500 ppb), fenoxycarb (0.5, 1 and 2 ppb), and epofenonane (50, 100 and 200 ppb). Exposure to these JH analogs resulted in chemical specific patterns of gene expression. The heat map analyses based on hierarchical clustering revealed a similar pattern between treatments with a high dose of methoprene and with epofenonane. In contrast, treatment with low to middle doses of methoprene resulted in similar profiles to fenoxycarb treatments. Hemoglobin and JH epoxide hydrolase genes clustered to be JH-responsive genes. These data suggest that fenoxycarb has high activity as a JH agonist, methoprene shows high toxicity and epofenonane works through a different mechanism compared with other JH analogs, agreeing with data of previously reported toxicity tests. In conclusion, D. magna DNA microarray is useful for classification of JH analogs and identification of JH-responsive genes. Juvenile hormone agonists induced gene expression in daphnids neonates was measured at 48 hours after exposure to methoprene (125, 250, 500 ppb), fenoxycarb (0.5, 1, 2 ppb), epofenonane (50, 100, 200) and DMF as a control. Three independent experiments were performed at each chemicals.
2013-12-31 | E-GEOD-47990 | biostudies-arrayexpress
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna. Four replicates each of five toxicant exposure groups of ~20 animals and four replicates of control, unexposed animals. Each control was compared to each exposed data set for a total of 16 comparisons per chemical condition.
2013-12-31 | E-GEOD-47064 | biostudies-arrayexpress
Project description:Nanowires (NWs), high-aspect-ratio nanomaterials, are increasingly used in technological materials and consumer products and may have toxicological characteristics distinct from nanoparticles. We carried out a comprehensive evaluation of the physicochemical stability of four silver nanowires (AgNWs) of two sizes and coatings and their toxicity to Daphnia magna. Inorganic aluminum-doped silica coatings were less effective than organic poly(vinyl pyrrolidone) coatings at preventing silver oxidation or Ag+ release and underwent a significant morphological transformation within 1 h following addition to low ionic strength Daphnia growth media. All AgNWs were highly toxic to D. magna but less toxic than ionic silver. Toxicity varied as a function of AgNW dimension, coating, and solution chemistry. Ag+ release in the media could not account for observed AgNW toxicity. Single-particle inductively coupled plasma mass spectrometry distinguished and quantified dissolved and nanoparticulate silver in microliter-scale volumes of Daphnia magna hemolymph with a limit of detection of approximately 10 ppb. The silver levels within the hemolymph of Daphnia exposed to both Ag+ and AgNW met or exceeded the initial concentration in the growth medium, indicating effective accumulation during filter feeding. Silver-rich particles were the predominant form of silver in hemolymph following exposure to both AgNWs and Ag+. Scanning electron microscopy imaging of dried hemolymph found both AgNWs and silver precipitates that were not present in the AgNW stock or the growth medium. Both organic and inorganic coatings on the AgNW were transformed during ingestion or absorption. Pathway, gene ontology, and clustering analyses of gene expression response indicated effects of AgNWs distinct from ionic silver on Daphnia magna.
2013-12-31 | GSE47064 | GEO
Project description:Daphnia magna is a bio-indicator organism accepted by several international water quality regulatory agencies. Current approaches for assessment of water quality rely on acute and chronic toxicity that provide no insight into the cause of toxicity. Recently, molecular approaches, such as genome wide gene expression responses, are enabling an alternative mechanism based approach to toxicity assessment. While these genomic methods are providing important mechanistic insight into toxicity, statistically robust prediction systems that allow the identification of chemical contaminants from the molecular response to exposure are needed. Here we apply advanced machine learning approaches to develop predictive models of contaminant exposure using a D. magna gene expression dataset for 36 chemical exposures. We demonstrate here that we can discriminate between chemicals belonging to different chemical classes including endocrine disruptors, metals and industrial chemicals based on gene expression. We also show that predictive models based on indices of whole pathway transcriptional activity can achieve comparable results while facilitating biological interpretability.
2013-01-17 | GSE43564 | GEO