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Sample records for daphnia magna exposed

  1. Bioaccumulation and oxidative stress in Daphnia magna exposed to arsenite and arsenate.

    PubMed

    Fan, Wenhong; Ren, Jinqian; Li, Xiaomin; Wei, Chaoyang; Xue, Feng; Zhang, Nan

    2015-11-01

    Arsenic pollution and its toxicity to aquatic organisms have attracted worldwide attention. The bioavailability and toxicity of arsenic are highly related to its speciation. The present study investigated the differences in bioaccumulation and oxidative stress responses in an aquatic organism, Daphnia magna, induced by 2 inorganic arsenic species (As(III) and As(V)). The bioaccumulation of arsenic, Na(+) /K(+) -adenosine triphosphatase (ATPase) activity, reactive oxygen species (ROS) content, total superoxide dismutase (SOD) activity, total antioxidative capability, and malondialdehyde content in D. magna were determined after exposure to 500 µg/L of arsenite and arsenate for 48 h. The results showed that the oxidative stress and antioxidative process in D. magna exposed to arsenite and arsenate could be divided into 3 phases, which were antioxidative response, oxidation inhibition, and antioxidative recovery. In addition, differences in bioaccumulation, Na(+) /K(+) -ATPase activity, and total SOD activity were also found in D. magna exposed to As(III) and As(V). These differences might have been the result of the high affinity of As(III) with sulfhydryl groups in enzymes and the structural similarity of As(V) to phosphate. Therefore, arsenate could be taken up by organisms through phosphate transporters, could substitute for phosphate in biochemical reactions, and could lead to a change in the bioaccumulation of arsenic and activity of enzymes. These characteristics were the possible reasons for the different toxicity mechanisms in the oxidative stress process of arsenite and arsenate. PMID:26084717

  2. Three-Dimensional Analysis of the Swimming Behavior of Daphnia magna Exposed to Nanosized Titanium Dioxide

    PubMed Central

    Noss, Christian; Dabrunz, André; Rosenfeldt, Ricki R.; Lorke, Andreas; Schulz, Ralf

    2013-01-01

    Due to their surface characteristics, nanosized titanium dioxide particles (nTiO2) tend to adhere to biological surfaces and we thus hypothesize that they may alter the swimming performance and behavior of motile aquatic organisms. However, no suitable approaches to address these impairments in swimming behavior as a result of nanoparticle exposure are available. Water fleas Daphnia magna exposed to 5 and 20 mg/L nTiO2 (61 nm; polydispersity index: 0.157 in 17.46 mg/L stock suspension) for 96 h showed a significantly (p<0.05) reduced growth rate compared to a 1-mg/L treatment and the control. Using three-dimensional video observations of swimming trajectories, we observed a treatment-dependent swarming of D. magna in the center of the test vessels during the initial phase of the exposure period. Ensemble mean swimming velocities increased with increasing body length of D. magna, but were significantly reduced in comparison to the control in all treatments after 96 h of exposure. Spectral analysis of swimming velocities revealed that high-frequency variance, which we consider as a measure of swimming activity, was significantly reduced in the 5- and 20-mg/L treatments. The results highlight the potential of detailed swimming analysis of D. magna for the evaluation of sub-lethal mechanical stress mechanisms resulting from biological surface coating and thus for evaluating the effects of nanoparticles in the aquatic environment. PMID:24260519

  3. Transcriptomic alterations in Daphnia magna embryos from mothers exposed to hypoxia.

    PubMed

    Lai, Keng-Po; Li, Jing-Woei; Chan, Christine Ying-Shan; Chan, Ting-Fung; Yuen, Karen Wing-Yee; Chiu, Jill Man-Ying

    2016-08-01

    Hypoxia occurs when dissolved oxygen (DO) falls below 2.8mgL(-1) in aquatic environments. It can cause trans-generational effects not only in fish, but also in the water fleas Daphnia. In this study, transcriptome sequencing analysis was employed to identify transcriptomic alterations induced by hypoxia in embryos of Daphnia magna, with an aim to investigate the mechanism underlying the trans-generational effects caused by hypoxia in Daphnia. The embryos (F1) were collected from adults (F0) that were previously exposed to hypoxia (or normoxia) for their whole life. De novo transcriptome assembly identified 18270 transcripts that were matched to the UniProtKB/Swiss-Prot database and resulted in 7419 genes. Comparative transcriptome analysis showed 124 differentially expressed genes, including 70 up- and 54 down-regulated genes under hypoxia. Gene ontology analysis further highlighted three clusters of genes which revealed acclimatory changes of haemoglobin, suppression in vitellogenin gene family and histone modifications. Specifically, the expressions of histone H2B, H3, H4 and histone deacetylase 4 (HDAC4) were deregulated. This study suggested that trans-generational effects of hypoxia on Daphnia may be mediated through epigenetic regulations of histone modifications. PMID:27399157

  4. Population level effects of multiwalled carbon nanotubes in Daphnia magna exposed to pulses of triclocarban.

    PubMed

    Simon, Anne; Preuss, Thomas G; Schäffer, Andreas; Hollert, Henner; Maes, Hanna M

    2015-08-01

    Due to the rapid increase of carbon nanotubes (CNT) applications and their inevitable release into the aquatic environment, CNT may interact with and further influence the fate and transport of other pollutants such as triclocarban (TCC). TCC is a high-production-volume chemical that is widely used as an antimicrobial agent, is continually released into the aquatic environment, and is biologically active and persistent. In the present study, the population test with Daphnia magna was performed over 93 days. Different treatments were examined: (a) control, (b) solvent control, (c) 1 mg CNT/L from the beginning, (d) 1 mg CNT/L as of day 14, (e) control with a 2-day pulse of 25 µg TCC/L on day 14, 41 µg TCC/L (day 54), and 61 µg TCC/L (day 68) and (f) same pulses of TCC with co-exposure to 1 mg CNT/L. Significant changes in all three size classes were observed as a result of the long-term exposure to 1 mg CNT/L. Increasing in number of neonates, and decreasing in number of juveniles and adults were observed. Moreover, daphnids were significantly smaller when they were exposed to MWCNT. The exposure with TCC led to size-dependent mortality in Daphnia magna populations and a subsequent recovery. Lower toxicity of TCC was observed, with the presence of MWCNT in the medium. The reported effects of TCC on population level were compared to the output of an individual-based Daphnia magna population model, in order to verify the model predictions with laboratory data. PMID:26003833

  5. THE GOOD, THE BAD, AND THE TOXIC: APPROACHING HORMESIS IN DAPHNIA MAGNA EXPOSED TO AN ENERGETIC COMPOUND

    PubMed Central

    Stanley, Jacob K.; Perkins, Edward J.; Habib, Tanwir; Sims, Jerre G.; Chappell, Pornsawan; Escalon, B. Lynn; Wilbanks, Mitchell; Garcia-Reyero, Natàlia

    2014-01-01

    A hormetic response is characterized by an opposite effect in small and large doses of chemical exposure, often resulting in seemingly beneficial effects at low doses. Here, we examined the potential mechanisms underlying the hormetic response of Daphnia magna to the energetic trinitrotoluene (TNT). Daphnia magna were exposed to TNT for 21 days and a significant increase in adult length and number of neonates was identified at low concentrations (0.002 – 0.22 mg/L TNT) while toxic effects were identified at high concentrations (0.97 mg/L TNT and above). Microarray analysis of D. magna exposed to 0.004, 0.12, and 1.85 mg/L TNT identified effects on lipid metabolism as a potential mechanism underlying hormetic effects. Lipidomic analysis of exposed D. magna supported the hypothesis that TNT exposure affected lipid and fatty acid metabolism, showing that hormetic effects could be related to changes in polyunsaturated fatty acids known to be involved in Daphnia growth and reproduction. Our results show that Daphnia exposed to low levels of TNT presented hormetic growth and reproduction enhancement while higher TNT concentrations had an opposite effect. Our results also show how a systems approach can help elucidate potential mechanisms of action and adverse outcomes. PMID:23898970

  6. Energy allocation in Daphnia magna exposed to xenobiotics: A biochemical approach

    SciTech Connect

    Coen, W.M. De; Janssen, C.R.; Persoone, G.

    1995-12-31

    A new approach to sublethal aquatic toxicity testing based on a biochemical assessment of the energy budget of Daphnia magna was developed and evaluated. With this method energy consumption (E{sub c}) is estimated by measuring the electron transport activity based on the calorimetric measurement of a tetrazolium salt reduction. Total available energy (E{sub a}) is assessed by measuring the lipid, protein and sugar content of the test organism using calorimetric methods. E{sub a} {minus} E{sup c} can subsequently be calculated and represents the ``surplus`` energy available for growth and reproduction. D. magna neonates were exposed to cadmium and 2,4-dichlorophenoxy acetic acid for 4 days after which the electron transport activity and the total lipid, protein and sugar content of the test organisms were determined. Using the enthalpy of combustion of the different macromolecular groups and converting the oxygen consumption into oxyenthalpic equivalents, an estimation of the total energy budget of the test organisms was made. Additionally, the age specific survival and reproduction and the growth of D. magna populations exposed to the same sublethal concentrations was assessed in 21 day life table experiments. Energy allocation patterns of stressed D. magna obtained with the new biochemical approach were similar to those obtained with the conventional Scope for Growth determinations. Although more research is needed, comparison between the suborganismal (biochemical) and supraorganismal (life table) endpoints indicate that the proposed short-term assay based on energy allocation could be used to predict long-term effects on the survival, growth and reproduction of daphnids.

  7. Growth of Daphnia magna exposed to mixtures of chemicals with diverse modes of action

    SciTech Connect

    Deneer, J.W.; Seinen, W.; Hermens, J.L.

    1988-02-01

    Concentrations causing inhibition of growth of Daphnia magna after 16 days of exposure were determined for nine chemicals that presumably act through different modes of action. The joint toxic effect of a mixture of these chemicals is found to be nonadditive.

  8. Daphnia magna mortality when exposed to titanium dioxide and fullerene (C60) nanoparticles.

    PubMed

    Lovern, Sarah B; Klaper, Rebecca

    2006-04-01

    Nanoparticles (1-100 nm) comprise the latest technological advances designed to do everything from absorb environmental toxins to deliver drugs to a target organ. Recently, however, they have come under scrutiny for the potential to cause environmental damage. Because compounds in this miniature size range have chemical properties that differ from those of their larger counterparts, nanoparticles deserve special attention. Our main objective was to assess the potential impact that nanoparticles may have on release into aquatic environments. We prepared titanium dioxide (TiO2) and fullerene (C60) nanoparticles by filtration in tetrahydrofuran or by sonication. Daphnia magna were exposed to the four solutions using U.S. Environmental Protection Agency 48-h acute toxicity tests. Images of the particle solutions were recorded using transmission-electron microscopy, and the median lethal concentration, lowest-observable-effect concentration, and no-observable-effect concentration were determined. Exposure to filtered C60 and filtered TiO2 caused an increase in mortality with an increase in concentration, whereas fullerenes show higher levels of toxicity at lower concentrations. Exposure to the sonicated solutions caused varied mortality. Understanding the potential impacts of nanoparticles will help to identify the most appropriate nanotechnology to preserve the aquatic environment while advancing medical and environmental technology. PMID:16629153

  9. Characterization of acetylcholinesterase inhibition and energy allocation in Daphnia magna exposed to carbaryl.

    PubMed

    Jeon, Junho; Kretschmann, Andreas; Escher, Beate I; Hollender, Juliane

    2013-12-01

    The inhibition of acetylcholinesterase (AChE) activity and energy allocation in the freshwater organism Daphnia magna exposed to carbaryl and potential recovery from the effects was examined. The binding of carbaryl-AChE was characterized through in vitro assays. To evaluate the recovery from inhibition and the alteration in energy budget, in vivo exposure and recovery regime tests were conducted. In comparison to diazoxon, the active metabolite of the insecticide diazinon, the stability of enzyme-carbaryl complex was fifteen times lower and the reactivity toward the active site was two times lower, resulting in approximately 30 times lower overall inhibition rate than for diazoxon. The in vitro reactivation rate constant of the inhibited enzyme and the in vivo recovery rate constant of AChE activity were 1.9 h⁻¹ and 0.12 h⁻¹ for carbaryl, respectively, which are much higher than the corresponding rate constants for diazoxon. The lower AChE inhibition and greater reactivation/recovery rates are in accordance with the lower toxicity of carbaryl compared to diazinon. Carbaryl exposure also altered the profile of the energy reserve: the decrease in lipid and glycogen and the increase in protein content resulted in the reduction of the total energy budget by about 45 mJ/g(ww). This corresponds to 26 percent of the available energy, which might allocate for external stressors. The mechanistic model of AChE inhibition is helpful to get an insight into (eco-)toxicological effects of AChE inhibitors on freshwater crustaceans under environmentally realistic conditions. PMID:24139064

  10. Response of biochemical biomarkers in the aquatic crustacean Daphnia magna exposed to silver nanoparticles.

    PubMed

    Ulm, Lea; Krivohlavek, Adela; Jurašin, Darija; Ljubojević, Marija; Šinko, Goran; Crnković, Tea; Žuntar, Irena; Šikić, Sandra; Vinković Vrček, Ivana

    2015-12-01

    The proliferation of silver nanoparticle (AgNP) production and use owing to their antimicrobial properties justifies the need to examine the resulting environmental impacts. The discharge of biocidal nanoparticles to water bodies may pose a threat to aquatic species. This study evaluated the effects of citrate-coated AgNPs on the standardized test organism Daphnia magna Straus clone MBP996 by means of biochemical biomarker response. AgNP toxicity was compared against the toxic effect of Ag(+). The toxicity endpoints were calculated based upon measured Ag concentrations in exposure media. For AgNPs, the NOAEC and LOAEC values at 48 h were 5 and 7 μg Ag/L, respectively, while these values were 0.5 and 1 μg Ag/L, respectively, for Ag(+). The EC50 at 48 h was computed to be 12.4 ± 0.6 and 2.6 ± 0.1 μg Ag/L for AgNPs and Ag(+), respectively, with 95 % confidence intervals of 12.1-12.8 and 2.3-2.8 μg Ag/L, respectively. These results indicate significant less toxicity of AgNP compared to free Ag(+) ions. Five biomarkers were evaluated in Daphnia magna neonates after acute exposure to Ag(+) or AgNPs, including glutathione (GSH) level, reactive oxygen species (ROS) content, and catalase (CAT), acetylcholinesterase (AChE), and superoxide dismutase (SOD) activity. AgNPs induced toxicity and oxidative stress responses in D. magna neonates at tenfold higher concentrations than Ag. Biochemical methods revealed a clear increase in AChE activity, decreased ROS level, increased GSH level and CAT activity, but no significant changes in SOD activity. As Ag(+) may dissolve from AgNPs, these two types of Ag could act synergistically and produce a greater toxic response. The observed remarkably high toxicity of AgNPs (in the parts-per-billion range) to crustaceans indicates that these organisms are a vulnerable link in the aquatic food chain with regard to contamination by nanosilver. Graphical Abstract ᅟ. PMID:26296504

  11. A metabolomic study on the responses of daphnia magna exposed to silver nitrate and coated silver nanoparticles.

    PubMed

    Li, LianZhen; Wu, Huifeng; Ji, Chenglong; van Gestel, Cornelis A M; Allen, Herbert E; Peijnenburg, Willie J G M

    2015-09-01

    We examined the short-term toxicity of AgNPs and AgNO3 to Daphnia magna at sublethal levels using (1)H NMR-based metabolomics. Two sizes of polyvinylpyrrolidone-coated AgNPs (10 and 40nm) were synthesized and characterized and their Ag(+) release was studied using centrifugal ultrafiltration and inductively coupled plasma mass spectrometry. Multivariate statistical analysis of the (1)H NMR spectra showed significant changes in the D. magna metabolic profiles following 48h exposure to both AgNP particle sizes and Ag(+) exposure. Most of the metabolic biomarkers for AgNP exposure, including 3-hydroxybutyrate, arginine, lysine and phosphocholine, were identical to those of the Ag(+)-exposed groups, suggesting that the dominant effects of both AgNPs were due to released Ag(+). The observed metabolic changes implied that the released Ag(+) induced disturbance in energy metabolism and oxidative stress, a proposed mechanism of AgNP toxicity. Elevated levels of lactate in all AgNP-treated but not in Ag(+)-treated groups provided evidence for Ag-NP enhanced anaerobic metabolism. These findings show that (1)H NMR-based metabolomics provides a sensitive measure of D. magna response to AgNPs and that further targeted assays are needed to elucidate mechanisms of action of nanoparticle-induced toxicity. PMID:25978415

  12. Transmission of DNA damage and increasing reprotoxic effects over two generations of Daphnia magna exposed to uranium.

    PubMed

    Plaire, Delphine; Bourdineaud, Jean-Paul; Alonzo, Antoine; Camilleri, Virginie; Garcia-Sanchez, Laurent; Adam-Guillermin, Christelle; Alonzo, Frédéric

    2013-11-01

    This study aimed to examine the mechanisms involved in the transgenerational increase in Daphnia magna sensitivity to waterborne depleted uranium (DU) under controlled laboratory conditions. Daphnids were exposed to concentrations ranging from 2 to 50 μg L(-1) over two successive generations. Genotoxic effects were assessed using random amplified polymorphic DNA and real time PCR (RAPD-PCR). Effects on life history (survival, fecundity and somatic growth) were monitored from hatching to release of brood 5. Different exposure regimes were tested to investigate the specific sensitivity of various life stages to DU. When daphnids were exposed continuously or from hatching to deposition of brood 5, results demonstrated that DNA damage accumulated in females and were transmitted to offspring in parallel with an increase in severity of effects on life history across generations. When daphnids were exposed during the embryo stage only, DU exposure induced transient DNA damage which was repaired after neonates were returned to a clean medium. Effects on life history remained visible after hatching and did not significantly increase in severity across generations. The present results suggest that DNA damage might be an early indicator of future effects on life history. PMID:24035969

  13. Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu(2+) on biotoxicity in Daphnia magna.

    PubMed

    Liu, Lingling; Fan, Wenhong; Lu, Huiting; Xiao, Wei

    2015-01-01

    Anatase TiO2 nanosheets (NSs) with exposed {001} facets have been widely used because of their high activity and particular surface atomic configuration. However, investigations on their biotoxicity are rare. In this study, bioaccumulation of five different TiO2 (with 10%, 61%, 71%, 74% and 78% exposed {001} facets), as well as copper and enzyme activities in Daphnia magna, are systematically investigated and rationalized. The results indicated that the addition of Cu(2+) enhanced agglomeration-sedimentation of TiO2, resulting in the reduction of TiO2 bioaccumulation by 10% to 26%. TiO2 nanoparticles (NPs) increased copper bioaccumulation by 9.8%, whereas the other four TiO2 nanosheets (NSs) decreased it by 43% to 53%, which depended on TiO2 variant adsorption and free Cu(2+) concentrations in the supernatant. The levels of superoxide dismutase (SOD) enzyme and Na(+)/K(+)-ATPase activities suggested that oxidative stress, instead of membrane damage, was the main toxicity in D. magna. Meanwhile, the SOD enzyme activities increased with decreasing Cu accumulation and increasing Ti accumulation because of the different functions of Cu and Ti in organisms. This research highlighted the important role of the percentage of exposed {001} facets in nanostructured TiO2 on bioaccumulation and biotoxicity of TiO2 and Cu(2+) in Daphnia magna. PMID:26242603

  14. Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu2+ on biotoxicity in Daphnia magna

    NASA Astrophysics Data System (ADS)

    Liu, Lingling; Fan, Wenhong; Lu, Huiting; Xiao, Wei

    2015-08-01

    Anatase TiO2 nanosheets (NSs) with exposed {001} facets have been widely used because of their high activity and particular surface atomic configuration. However, investigations on their biotoxicity are rare. In this study, bioaccumulation of five different TiO2 (with 10%, 61%, 71%, 74% and 78% exposed {001} facets), as well as copper and enzyme activities in Daphnia magna, are systematically investigated and rationalized. The results indicated that the addition of Cu2+ enhanced agglomeration-sedimentation of TiO2, resulting in the reduction of TiO2 bioaccumulation by 10% to 26%. TiO2 nanoparticles (NPs) increased copper bioaccumulation by 9.8%, whereas the other four TiO2 nanosheets (NSs) decreased it by 43% to 53%, which depended on TiO2 variant adsorption and free Cu2+ concentrations in the supernatant. The levels of superoxide dismutase (SOD) enzyme and Na+/K+-ATPase activities suggested that oxidative stress, instead of membrane damage, was the main toxicity in D. magna. Meanwhile, the SOD enzyme activities increased with decreasing Cu accumulation and increasing Ti accumulation because of the different functions of Cu and Ti in organisms. This research highlighted the important role of the percentage of exposed {001} facets in nanostructured TiO2 on bioaccumulation and biotoxicity of TiO2 and Cu2+ in Daphnia magna.

  15. Effects of the interaction between TiO2 with different percentages of exposed {001} facets and Cu2+ on biotoxicity in Daphnia magna

    PubMed Central

    Liu, Lingling; Fan, Wenhong; Lu, Huiting; Xiao, Wei

    2015-01-01

    Anatase TiO2 nanosheets (NSs) with exposed {001} facets have been widely used because of their high activity and particular surface atomic configuration. However, investigations on their biotoxicity are rare. In this study, bioaccumulation of five different TiO2 (with 10%, 61%, 71%, 74% and 78% exposed {001} facets), as well as copper and enzyme activities in Daphnia magna, are systematically investigated and rationalized. The results indicated that the addition of Cu2+ enhanced agglomeration–sedimentation of TiO2, resulting in the reduction of TiO2 bioaccumulation by 10% to 26%. TiO2 nanoparticles (NPs) increased copper bioaccumulation by 9.8%, whereas the other four TiO2 nanosheets (NSs) decreased it by 43% to 53%, which depended on TiO2 variant adsorption and free Cu2+ concentrations in the supernatant. The levels of superoxide dismutase (SOD) enzyme and Na+/K+-ATPase activities suggested that oxidative stress, instead of membrane damage, was the main toxicity in D. magna. Meanwhile, the SOD enzyme activities increased with decreasing Cu accumulation and increasing Ti accumulation because of the different functions of Cu and Ti in organisms. This research highlighted the important role of the percentage of exposed {001} facets in nanostructured TiO2 on bioaccumulation and biotoxicity of TiO2 and Cu2+ in Daphnia magna. PMID:26242603

  16. Development of resistance to cyfluthrin and naphthalene among Daphnia magna.

    PubMed

    Brausch, John M; Smith, Philip N

    2009-07-01

    In this study, Daphnia magna were exposed to a pyrethroid insecticide (cyfluthrin) or a polycyclic aromatic hydrocarbon (naphthalene) for 12 generations to evaluate development of resistance followed by a 12 generation recovery period. Twenty-four hour old D. magna were exposed to concentrations of each chemical resulting in 50-70% mortality to select for the least sensitive individuals. LC50 values, survival, reproductive output, and time to first brood in stressor-exposed and control D. magna were recorded for each generation. Significant changes in LC50 values were observed after 4 generations and then declined after 6-10 generations post-exposure. D. magna were 5 times less sensitive to cyfluthrin and 3 times less sensitive to naphthalene as compared to controls after 12 generations of exposure. There were no differences in survival, time to first brood, or total number of offspring produced between control and either of the resistant F13 D. magna. Cyfluthrin exposed D. magna exhibited cross-resistance to DDT and methyl parathion, and naphthalene resistant D. magna were less sensitive than controls to both pyrene and benz(a)anthracene. When the cytochrome P450 inhibitor piperonyl butoxide was used in conjunction with cyfluthrin and naphthalene the sensitivity of resistant and control D. magna were equal, suggesting P450s were responsible for conveying resistance. This study demonstrates that life history and organisms' capacity to develop resistance is important to consider ensuring accuracy of ecological risk assessments. PMID:19399609

  17. Changes in iTRAQ-Based Proteomic Profiling of the Cladoceran Daphnia magna Exposed to Microcystin-Producing and Microcystin-Free Microcystis aeruginosa.

    PubMed

    Lyu, Kai; Meng, Qingguo; Zhu, Xuexia; Dai, Daoxin; Zhang, Lu; Huang, Yuan; Yang, Zhou

    2016-05-01

    Global warming and increased nutrient fluxes cause cyanobacterial blooms in freshwater ecosystems. These phenomena have increased the concern for human health and ecosystem services. The mass occurrences of toxic cyanobacteria strongly affect freshwater zooplankton communities, especially the unselective filter feeder Daphnia. However, the molecular mechanisms of cyanobacterial toxicity remain poorly understood. This study is the first to combine the established body growth rate (BGR), which is an indicator of life-history fitness, with differential peptide labeling (iTRAQ)-based proteomics in Daphnia magna influenced by microcystin-producing (MP) and microcystin-free (MF) Microcystis aeruginosa. A significant decrease in BGR was detected when D. magna was exposed to MP or MF M. aeruginosa. Conducting iTRAQ proteomic analyses, we successfully identified and quantified 211 proteins with significant changes in expression. A cluster of orthologous groups revealed that M. aeruginosa-affected differential proteins were strongly associated with lipid, carbohydrate, amino acid, and energy metabolism. These parameters could potentially explain the reduced fitness based on the cost of the substance metabolism. PMID:27057760

  18. Compounds altering fat storage in Daphnia magna.

    PubMed

    Jordão, Rita; Garreta, Elba; Campos, Bruno; Lemos, Marco F L; Soares, Amadeu M V M; Tauler, Romà; Barata, Carlos

    2016-03-01

    The analysis of lipid disruptive effects in invertebrates is limited by our poor knowledge of the lipid metabolic pathways. A recent study showed that tributyltin activated the ecdysteroid, juvenile hormone and retinoic X receptor signaling pathways, and disrupted the dynamics of neutral lipids in the crustacean Daphnia magna impairing the transfer of triacylglycerols to eggs and hence promoting their accumulation in post-spawning females. Tributyltin disruptive effects correlated with lower fitness for offspring and adults. The present study aims to addresses effects of existing compounds on storage lipids in post-spawning females and their health effects. D. magna individuals were exposed 12 chemicals that included vertebrate obesogens (tributyltin, triphenyltin, bisphenol A, nonylphenol, di-2-ethylhexyl phthalate), other contaminants known to affect arthropods (pyriproxyfen, fenarimol, methoprene, emamectin benzoate and fluoxetine), as well as the natural hormones methyl farnesoate and 20-hydroxyecdysone. Reproductive effects were also assessed. Quantitative changes in storage lipids accumulated in lipid droplets were studied using Nile red staining, which showed a close relationship with whole organism levels of triacylglycerols. Ten compounds altered storage lipids in a concentration related manner enhancing (tributyltin, bisphenol A, methyl farnesoate, pyriproxyfen and 20-hydroxyecdysone) or decreasing (nonylphenol, fenarimol, emamectin benzoate, methoprene and fluoxetine) their levels in post-spawning females. Eight compounds that altered lipid levels also had detrimental effects on growth and/or reproduction. PMID:26747981

  19. Qualitative assessment of genotoxicity using random amplified polymorphic DNA: Comparison of genomic template stability with key fitness parameters in Daphnia magna exposed to benzo[a]pyrene

    SciTech Connect

    Atienzar, F.A.; Conradi, M.; Evenden, A.J.; Jha, A.N.; Depledge, M.H.

    1999-10-01

    A method of DNA profiling using the random amplified polymorphic DNA (RAPD) was used to assess toxicant-induced DNA effects in laboratory populations of Daphnia magna exposed to varying concentrations of the genotoxic hydrocarbon benzo[a]pyrene. These effects, represented by changes in the RAPD profiles, were compared with a number of key ecological fitness parameters (age-specific survival, age-specific fecundity, net reproductive rate, and intrinsic rate of population increase). Not only was the RAPD profiling method shown to be a rapid and reproducible assay of toxicant-induced DNA effects, but the qualitative measure of genomic template stability compared favorably with the traditional indices of fitness. The RAPD profiles, however, exhibited higher sensitivity in detecting toxic effects. The significance of these findings for future ecotoxicological studies is discussed.

  20. The random amplified polymorphic DNA (RAPD) assay to determine DNA alterations, repair and transgenerational effects in B(a)P exposed Daphnia magna.

    PubMed

    Atienzar, Franck A; Jha, Awadhesh N

    2004-08-18

    The random amplified polymorphic DNA (RAPD) is a useful assay for the detection of genotoxin-induced DNA damage and mutations. In this study, we have further evaluated the potential of this assay to measure benzo(a)pyrene [B(a)P]-induced DNA changes, and repair (in kinetic experiments) as well as transgenerational effects in the water fleas, Daphnia magna. The organisms, which reproduce parthenogenetically, were exposed to 50 microg L(-1) B(a)P for 3 or 6 days and were allowed to recover in clean medium for 12 or 9 days, respectively. Qualitative and quantitative changes were observed in RAPD profiles generated not only from the B(a)P exposed Daphnia but also from previously treated organisms during the recovery experiments. The fact that some of the RAPD changes disappeared at the end of both recovery experiments suggested that the DNA effects were fully repaired or reversed. In addition, some of the B(a)P-induced RAPD alterations detected in parental D. magna were also observed in the offspring patterns. This suggested that DNA alterations that occurred in germ cells were probably transmitted to the next cohorts. The present study shows that the RAPD method can be useful to qualitatively assess the kinetics of DNA changes, repair and transgenerational effects and such effects could potentially be linked to survival and reproductive success at higher levels of biological organisation. In addition, the water fleas have efficient capabilities to repair or reverse B(a)P-induced DNA effects. Finally, unrepaired or misrepaired genetic damage induced by genotoxins such as B(a)P could be transmitted to next generations in these parthenogenetically reproducing organisms. PMID:15288546

  1. Sucralose Induces Biochemical Responses in Daphnia magna

    PubMed Central

    Eriksson Wiklund, Ann-Kristin; Adolfsson-Erici, Margaretha; Liewenborg, Birgitta; Gorokhova, Elena

    2014-01-01

    The intense artificial sweetener sucralose has no bioconcentration properties, and no adverse acute toxic effects have been observed in standard ecotoxicity tests, suggesting negligible environmental risk. However, significant feeding and behavioural alterations have been reported in non-standard tests using aquatic crustaceans, indicating possible sublethal effects. We hypothesized that these effects are related to alterations in acetylcholinesterase (AChE) and oxidative status in the exposed animals and investigated changes in AChE and oxidative biomarkers (oxygen radical absorbing capacity, ORAC, and lipid peroxidation, TBARS) in the crustacean Daphnia magna exposed to sucralose (0.0001–5 mg L−1). The sucralose concentration was a significant positive predictor for ORAC, TBARS and AChE in the daphnids. Moreover, the AChE response was linked to both oxidative biomarkers, with positive and negative relationships for TBARS and ORAC, respectively. These joint responses support our hypothesis and suggest that exposure to sucralose may induce neurological and oxidative mechanisms with potentially important consequences for animal behaviour and physiology. PMID:24699280

  2. Gene transcription patterns and energy reserves in Daphnia magna show no nanoparticle specific toxicity when exposed to ZnO and CuO nanoparticles.

    PubMed

    Adam, Nathalie; Vergauwen, Lucia; Blust, Ronny; Knapen, Dries

    2015-04-01

    There is still a lot of contradiction on whether metal ions are solely responsible for the observed toxicity of ZnO and CuO nanoparticles to aquatic species. While most experiments have studied nanoparticle effects at organismal levels (e.g. mortality, reproduction), effects at lower levels of biological organization may clarify the role of metal ions, nanoparticles and nanoparticle aggregates. In this study, the effect of ZnO and CuO nanoparticles was tested at two lower levels: energy reserves and gene transcription and compared with zinc and copper salts. Daphnia magna was exposed during 96h to 10% immobilization concentrations of all chemicals, after which daphnids were sampled for determination of glycogen, lipid and protein concentration and for a differential gene transcription analysis using microarray. The dissolved, nanoparticle and aggregated fraction in the medium was characterized. The results showed that ZnO nanoparticles had largely dissolved directly after addition to the test medium. The CuO nanoparticles mostly formed aggregates, while only a small fraction dissolved. The exposure to zinc (both nano and metal salt) had no effect on the available energy reserves. However, in the copper exposure, the glycogen, lipid and protein concentration in the exposed daphnids was lower than in the unexposed ones. When comparing the nanoparticle (ZnO or CuO) exposed daphnids to the metal salt (zinc or copper salt) exposed daphnids, the microarray results showed no significantly differentially transcribed gene fragments. The results indicate that under the current exposure conditions the toxicity of ZnO and CuO nanoparticles to D. magna is solely caused by toxic metal ions. PMID:25704829

  3. Effects of acid precipitation on Daphnia magna

    SciTech Connect

    Parent, S.; Cheetham, R.D.

    1980-08-01

    Pollutants derived from fossil fuel combustion and precipitated from the atmosphere have substantially increased in the past decades. These materials, precipitated in such industrialized areas as southeastern Canada, have caused considerable alterations in aquatic ecosystems. Precipitation over most of the eastern United States is presently 10 to 500 times more acidic than is natural. Most affected aquatic ecosystems contain oligotrophic waters in regions of thin poorly buffered soils. Zooplankton are an important link in food chains of aquatic ecosystems and their disappearance or decline could drastically affect trophic relationships. Declines in zooplankton density in response to acid precipitation have been reported and short term survival of Daphnia pulex between pH 4.3 and 10.4; however, its potential for reproduction was limited to a fairly narrow range. Anderson (1944) noted the advantages of using daphnia as test organisms, and concluded that Daphnia magna was representative of other abundant zooplankton in sensitivity to toxic substances.

  4. Responses of Daphnia magna to pulsed exposures of arsenic.

    PubMed

    Hoang, Tham C; Gallagher, Jeffrey S; Klaine, Stephen J

    2007-06-01

    Research on the toxicity of arsenic has focused on sublethal effects that do not provide sufficient information for risk estimation. While most studies have focused on organism response to constant arsenic exposures, organisms in nature are exposed to fluctuating As concentrations. Consequently, results obtained from standardized bioassays with constant exposures may not adequately characterize risk to indigenous biota. This research was designed to characterize the response of Daphnia magna to fluctuating arsenic exposures during 21-day experiments. At concentrations > or =3000 microg/L As, 21-day pulsed exposure mortality increased as a function of exposure concentration and duration. In addition, 21-day pulsed exposure mortality increased with increasing recovery time. Pulsed As exposure did not affect the growth of D. magna over 21 days. Twenty-one day accumulative reproduction of D. magna was only affected by pulsed exposures of high As concentration and long durations. PMID:17497644

  5. Accumulation of dieldrin in an alga (Scenedesmus obliquus), Daphnia magna, and the guppy (Poecilia reticulata)

    USGS Publications Warehouse

    Reinert, Robert E.

    1972-01-01

    Scenedesmus obliquus, Daphnia magna, and Poecilia reticulata accumulated dieldrin directly from water; average concentration factors (concentration in organism, dry weight, divided by concentration in water) were 1282 for the alga, 13,954 for D. magna, and 49,307 (estimated) for the guppy. The amount accumulated by each species at equilibrium (after about 1.5, 3-4, and 18 days, respectively) was directly proportional to the concentration of dieldrin in the water. Daphnia magna and guppies accumulated more dieldrin from water than from food that had been exposed to similar concentrations in water. When guppies were fed equal daily rations of D. magna containing different concentrations of insecticide, the amounts of dieldrin accumulated by the fish were directly proportional to the concentration in D. magna; when two lots of guppies were fed different quantities of D. magna (10 and 20 organisms per day) containing identical concentrations of dieldrin, however, the amounts accumulated did not differ substantially.

  6. The use of liposomes to differentiate between the effects of nickel accumulation and altered food quality in Daphnia magna exposed to dietary nickel.

    PubMed

    Evens, Roel; De Schamphelaere, Karel A C; Balcaen, Lieve; Wang, Yingying; De Roy, Karen; Resano, Martin; Flórez, M; Boon, Nico; Vanhaecke, Frank; Janssen, Colin R

    2012-03-01

    A potential drawback of traditional dietary metal toxicity studies is that it is difficult to distinguish between the direct toxicity of the metal and indirect effects caused by altered concentrations of essential nutrients in the metal-contaminated diet. In previous studies it has become clear that this can hamper the study of the real impact of dietary metal exposure and also complicates the analysis of the mechanisms of dietary metal toxicity in filter-feeding freshwater invertebrates like Daphnia magna. This problem has been partly circumvented by the production of liposomes, since these vectors are invulnerable to metal-induced food quality shifts and as such can be applied to study the mechanisms of dietary metal toxicity without the confounding effect of nutritional quality shifts. The aim of current study was to evaluate if there is relevance for dietary Ni toxicity under natural exposures, i.e., when D. magna is exposed to dietary Ni via living algae, and secondly, to quantify how nutritional quality shifts contribute to the toxic effects that are observed when algae are used as contaminated food vectors. For this aim, liposomes were prepared by the hydration of phosphatidylcholine in media containing 0 (control), 10, 50, 100 and 500 mg Ni/L. The liposome particles were then mixed with uncontaminated green algae in a 1/10 ratio (on a dry wt basis) to make up diets with constant nutrient quality and varying Ni contents (i.e., 1.2 μg Ni/g dry wt in the control and 18.7, 140.3, 165.0 and 501.6 μg Ni/g dry wt in the Ni-contaminated diet, respectively). A second food type was prepared on the basis of a 1/10 mixture (on a dry weight basis) of control liposomes and Ni-contaminated algae, representing a diet that differed in Ni content (i.e., 1.2, 26.8, 84.7, 262.3 and 742.7 μg Ni/g dry wt) and concentrations of essential nutrients (in terms of P and omega 3 poly-unsaturated fatty acids like eicosapentaenoic acid and α-linolenic acid). Both diets were then

  7. Gene response of CYP360A, CYP314, and GST and whole-organism changes in Daphnia magna exposed to ibuprofen.

    PubMed

    Wang, Lan; Peng, Ying; Nie, Xiangping; Pan, Benben; Ku, Peijia; Bao, Shuang

    2016-01-01

    The fate and ecological impact of non-steroidal anti-inflammatory drugs (NSAIDs) in aquatic environments has gained increasingly concern recently. However, limited information is provided about the toxicity mechanism of NSAIDs to aquatic invertebrates. In the present study, we investigated the expression of CYP360A, CYP314, and GST genes involved in the detoxification process and the responses of their associated enzymes activity, as well as whole-organism changes in Daphnia magna exposed to environmentally relevant concentrations of ibuprofen (IBU). Results showed that the total amount of eggs produced per female, total number of brood per female, and body length were significantly decreased under IBU exposure, suggesting the effects of chronic IBU exposure on growth and reproduction of D. magna cannot be ignored. In gene expression level, the CYP360A gene, homologue to CYP3A in mammalian, showed inhibition at low concentration of IBU (0.5μg·L(-1)) and induction at high concentration of IBU (50μg·L(-1)). GST gene also exhibited a similar performance to CYP3A. CYP314 displayed inhibition for short time exposure (6h) and induced with prolonged exposure time (48h) at low concentration of IBU (0.5μg·L(-1)). Erythromycin N-demethylase (ERND) and aminopyrine N-demethylase (APND) related to cytochrome oxidase P450 (CYPs) were inhibited for short time exposure (6h) to IBU and then activated with prolonged exposure time (48h) at low concentration of IBU (0.5μg·L(-1)), while EROD showed a dose-dependent pattern under IBU exposure. As for antioxidative system, induction of glutathione S-transferase (GST), superoxide dismutase (SOD), and catalase (CAT) was observed in short-term exposure to IBU. Meanwhile, methane dicarboxylic aldehyde (MDA) content increased with the increasing IBU concentration and the delayed exposure time, displaying obvious dose- and time-dependent pattern. In summary, IBU significantly altered some physiological and biochemical parameters and

  8. The response of European Daphnia magna Straus and Australian Daphnia carinata King to changes in geomagnetic field.

    PubMed

    Krylov, Viacheslav V; Bolotovskaya, Irina V; Osipova, Elena A

    2013-03-01

    This study investigates the effects of lifelong exposure to reversed geomagnetic and zero geomagnetic fields (the latter means absence of geomagnetic field) on the life history of Daphnia carinata King from Australia and Daphnia magna Straus from Europe. Considerable deviation in the geomagnetic field from the usual strength, leads to a decrease in daphnia size and life span. Reduced brood sizes and increased body length of neonates are observed in D. magna exposed to unusual magnetic background. The most apparent effects are induced by zero geomagnetic field in both species of Daphnia. A delay in the first reproduction in zero geomagnetic field is observed only in D. magna. No adaptive maternal effects to reversed geomagnetic field are found in a line of D. magna maintained in these magnetic conditions for eight generations. Integrally, the responses of D. magna to unusual geomagnetic conditions are more extensive than that in D. carinata. We suggest that the mechanism of the effects of geomagnetic field reversal on Daphnia may be related to differences in the pattern of distribution of the particles that have a magnetic moment, or to moving charged organic molecules owing to a change in combined outcome and orientation of the geomagnetic field and Earth's gravitational field. The possibility of modulation of self-oscillating processes with changes in geomagnetic field is also discussed. PMID:23320498

  9. Protective effects of ectoine on heat-stressed Daphnia magna.

    PubMed

    Adam, Bownik; Zofia, Stępniewska; Tadeusz, Skowroński

    2014-12-01

    Ectoine (ECT) is an amino acid produced and accumulated by halophilic bacteria in stressful conditions in order to prevent the loss of water from the cell. There is a lack of knowledge on the effects of ECT in heat-stressed aquatic animals. The purpose of our study was to determine the influence of ECT on Daphnia magna subjected to heat stress with two temperature gradients: 1 and 0.1 °C/min in the range of 23-42 °C. Time to immobilisation, survival during recovery, swimming performance, heart rate, thoracic limb movement and the levels of heat shock protein 70 kDa 1A (HSP70 1A), catalase (CAT) and nitric oxide species (NOx) were determined in ECT-exposed and unexposed daphnids; we showed protective effects of ECT on Daphnia magna subjected to heat stress. Time to immobilisation of daphnids exposed to ECT was longer when compared to the unexposed animals. Also, survival rate during the recovery of daphnids previously treated with ECT was higher. ECT significantly attenuated a rapid increase of mean swimming velocity which was elevated in the unexposed daphnids. Moreover, we observed elevation of thoracic limb movement and modulation of heart rate in ECT-exposed animals. HSP70 1A and CAT levels were reduced in the presence of ECT. On the other hand, NOx level was slightly elevated in both ECT-treated and unexposed daphnids, however slightly higher NOx level was found in ECT-treated animals. We conclude that the exposure to ectoine has thermoprotective effects on Daphnia magna, however their mechanisms are not associated with the induction of HSP70 1A. PMID:25223383

  10. Multigenerational cadmium acclimation and biokinetics in Daphnia magna.

    PubMed

    Guan, Rui; Wang, Wen-Xiong

    2006-05-01

    A Cd exposure (3 microg L(-1)) experiment was conducted for six successive generations to investigate the responses to chronic Cd stress in Daphnia magna. We observed a biphasic accumulation of Cd in the six generations and suggested a similar pattern with respect to daphnids' tolerance. Cd assimilation efficiencies, daphnid growth, and reproduction corresponded to the changes of tolerance, which was partially accounted for by metallothionein induction. When maternally exposed neonates grew in Cd-free water for one or two generations, their growth, MT concentration and biokinetic parameters partially or totally recovered. The rapid recovery suggests the high potential for ecological restoration from Cd pollution. Our results indicate that the tolerance of sensitive D. magna clones to Cd was dependent on long-term or multigenerational exposure. The tolerance developed within the first several generations might not be maintained, and the animals may become even more sensitive to Cd stress in subsequent generations. PMID:16202491

  11. Molecular impact of juvenile hormone agonists on neonatal Daphnia magna.

    PubMed

    Toyota, Kenji; Kato, Yasuhiko; Miyakawa, Hitoshi; Yatsu, Ryohei; Mizutani, Takeshi; Ogino, Yukiko; Miyagawa, Shinichi; Watanabe, Hajime; Nishide, Hiroyo; Uchiyama, Ikuo; Tatarazako, Norihisa; Iguchi, Taisen

    2014-05-01

    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 understand better 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 were clustered as 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 the classification of JH analogs and identification of JH-responsive genes. PMID:24038158

  12. An assessment of the bioaccumulation of estrone in Daphnia magna.

    PubMed

    Gomes, Rachel L; Deacon, Hannah E; Lai, Ka M; Birkett, Jason W; Scrimshaw, Mark D; Lester, John N

    2004-01-01

    The bioaccumulation of estrone by Daphnia magna was determined. Direct uptake via the aqueous medium occurred within the first 16 h. A bioconcentration factor of 228 was established over all temporal periods. Ingestion via Chlorella vulgaris gave a partitioning factor of 24, which may approximate to a biomagnification factor assuming steady state conditions. These preliminary results indicate that the partitioning to Daphnia magna via the food source, C. vulgaris is less significant than bioconcentration. PMID:14768873

  13. A DAPHNIA MAGNA SHORT-TERM SURVIVAL AND GROWTH TEST

    EPA Science Inventory

    With the change in acceptable test temperatures for invertebrate toxicity tests from <20oC to 25oC, it is now possible to use Daphnia magna for short-term chronic testing. When cultured at 25oC the dry weight of <24 hr old D. magna ranges from 7 to 15 g depending upon nutrition,...

  14. Target gene approaches: Gene expression in Daphnia magna exposed to predator-borne kairomones or to microcystin-producing and microcystin-free Microcystis aeruginosa

    PubMed Central

    2009-01-01

    Background Two major biological stressors of freshwater zooplankton of the genus Daphnia are predation and fluctuations in food quality. Here we use kairomones released from a planktivorous fish (Leucaspius delineatus) and from an invertebrate predator (larvae of Chaoborus flavicans) to simulate predation pressure; a microcystin-producing culture of the cyanobacterium Microcystis aeruginosa and a microcystin-deficient mutant are used to investigate effects of low food quality. Real-time quantitative polymerase chain reaction (QPCR) allows quantification of the impact of biotic stressors on differential gene activity. The draft genome sequence for Daphnia pulex facilitates the use of candidate genes by precisely identifying orthologs to functionally characterized genes in other model species. This information is obtained by constructing phylogenetic trees of candidate genes with the knowledge that the Daphnia genome is composed of many expanded gene families. Results We evaluated seven candidate reference genes for QPCR in Daphnia magna after exposure to kairomones. As a robust approach, a combination normalisation factor (NF) was calculated based on the geometric mean of three of these seven reference genes: glyceraldehyde-3-phosphate dehydrogenase, TATA-box binding protein and succinate dehydrogenase. Using this NF, expression of the target genes actin and alpha-tubulin were revealed to be unchanged in the presence of the tested kairomones. The presence of fish kairomone up-regulated one gene (cyclophilin) involved in the folding of proteins, whereas Chaoborus kairomone down-regulated the same gene. We evaluated the same set of candidate reference genes for QPCR in Daphnia magna after exposure to a microcystin-producing and a microcystin-free strain of the cyanobacterium Microcystis aeruginosa. The NF was calculated based on the reference genes 18S ribosomal RNA, alpha-tubulin and TATA-box binding protein. We found glyceraldehyde-3-phosphate dehydrogenase and

  15. EFFECT OF AGE ON SENSITIVITY OF 'DAPHNIA MAGNA' TO CADMIUM, COPPER AND CYANAZINE

    EPA Science Inventory

    Daphnia magna were exposed to cadmium, copper and cyanazine to determine the relative sensitivities of several age groups: less than 4 h, less than 24 h, 1 d, 2 d, 3 d, 4 d, 5 d and 6 d old. Mean cadmium 48-h EC50 values for each age group ranged from 23 to 164 micrograms/L. Mean...

  16. Phototoxic effects of titanium dioxide nanoparticles on Daphnia magna

    NASA Astrophysics Data System (ADS)

    Mansfield, Charles M.

    Titanium dioxide nanoparticles (TiO2-NP) are one of the most abundantly utilized nanomaterials in the world. Studies have demonstrated the mechanism of acute toxicity in TiO2-NP to be the production of reactive oxygen species (ROS) leading to oxidative stress and mortality in exposed organisms. It has also been demonstrated that the anatase crystalline conformation is capable of catalyzing the cleavage of water molecules to further increase the concentration of ROS in the presence of ultraviolet radiation. This photoenhanced toxicity significantly lowers the toxicity threshold of TiO2-NP to environmentally relevant concentrations (ppb). The goal of this study was to determine whether dietary uptake and accumulation of TiO2-NP in the aquatic filter feeder Daphnia magna resulted in photoenhanced toxicity. D. magna and S. caprincornatum were exposed to aqueous solutions of 20ppm and 200ppm TiO2-NP for 24hrs and then transferred to clean moderately hard water. Samples were taken at various time points, dried, and TiO 2 quantified using ICP-MS. Toxicity assays were run on D. magna using three TiO2-NP (20ppm, 200ppm) exposure protocols and two ultraviolet radiation treatments. The first exposure group was exposed to aqueous solutions of TiO2-NP for the duration of the test. The second exposure group was exposed to TiO2-NP for an hour and then transferred to clean water. The third exposure group was fed S. capricornatum that had been allowed to adsorb TiO2-NP. All samples were then placed in an outdoor UV exposure system and exposed to either full spectrum sunlight (with UV) or filtered sunlight (no UV). Here we show that TiO2 uptake peaked at one hour of exposure likely due to sedimentation of the particles out of suspension, thus decreasing bioavailability for the duration of the test. Interestingly, when D. magna were moved to clean water, aqueous concentrations of TiO2 increase as a result of depuration from the gut tract. Data also suggests these excreted particles

  17. Behavioral and physiological changes in Daphnia magna when exposed to nanoparticle suspensions (titanium dioxide, nano-C60, and C60HxC70Hx).

    PubMed

    Lovern, Sarah B; Strickler, J Rudi; Klaper, Rebecca

    2007-06-15

    Little is known aboutthe impact manufactured nanoparticles will have on aquatic organisms. Previously, we demonstrated that toxicity differs with nanoparticle type and preparation and observed behavioral changes upon exposure to the more lethal nanoparticle suspensions. In this experiment, we quantified these behavioral and physiological responses of Daphnia magna at sublethal nanoparticle concentrations. Titanium dioxide (TiO2) and fullerenes (nano-C60) were chosen for their potential use in technology. Other studies suggest that addition of functional groups to particles can affect their toxicity to cell cultures, but it is unknown if the same is true at the whole organism level. Therefore, a fullerene derivative, C60HxC70Hx, was also used to examine how functional groups affect Daphnia response. Using a high-speed camera, we quantified several behavior and physiological parameters including hopping frequency, feeding appendage and postabdominal curling movement, and heart rate. Nano-C60 was the only suspension to cause a significant change in heart rate. Exposure to both nano-C60 and C60HxC70Hx suspensions caused hopping frequency and appendage movement to increase. These results are associated with increased risk of predation and reproductive decline. They indicate that certain nanoparticle types may have impacts on population and food web dynamics in aquatic systems. PMID:17626453

  18. Increasing toxicity of enrofloxacin over four generations of Daphnia magna.

    PubMed

    Dalla Bona, Mirco; Lizzi, Francesca; Borgato, Arianna; De Liguoro, Marco

    2016-10-01

    The effects of both continuous and alternate exposure to 2mgL(-1) of enrofloxacin (EFX) on survival, growth and reproduction were evaluated over four generations of Daphnia magna. Mortality increased, reaching 100% in most groups by the end of the third generation. Growth inhibition was detected in only one group of the fourth generation. Reproduction inhibition was >50% in all groups and, in second and third generations, groups transferred to pure medium showed a greater inhibition of reproduction than those exposed to EFX. To verify whether the effects observed in these groups could be explained by the perinatal exposure to the antibacterial, a reproduction test with daphnids obtained from in vitro exposed D. magna embryos was also carried out. Perinatal exposure to EFX seemed to act as an 'all-or-nothing' toxicity effect as 31.4% of embryos died, but the surviving daphnids did not show any inhibition of reproduction activity. However, the embryonic mortality may at least partially justify the inhibition of reproduction observed in exposed groups along the multigenerational test. Concluding, the multigenerational test with D. magna did show disruption to a population that cannot be evidenced by the official tests. The increasing deterioration across generations might be inferred as the consequence of heritable alterations. Whilst the concentration tested was higher than those usually detected in the natural environment, the increasing toxicity of EFX across generations and the possible additive toxicity of fluoroquinolone mixtures, prevent harm to crustacean populations by effects in the real context from being completely ruled out. PMID:27379980

  19. Influence of organism age on metal toxicity to Daphnia magna.

    PubMed

    Hoang, Tham C; Klaine, Stephen J

    2007-06-01

    Aquatic organisms living in surface water experience contaminant exposure at different life stages. While some investigators have examined the influence of organism age on the toxicity of pollutants, the general assumption in toxicology has been that young organisms were more sensitive than older organisms. In fact, some standardized toxicity tests call for the use of organisms less than 24 h old. This research characterized the age sensitivity of the water flea Daphnia magna to copper, zinc, selenium, and arsenic. During 21-d toxicity tests, organisms were exposed to a single 12-h pulse of either 70 microg/L Cu, 750 microg/L Zn, 1000 microg/L Se, or 5000 microg/L As at different ages ranging from 3 h to 10 d old. Mortality and reproduction were compiled over 21 d. During the juvenile stage, mortality increased and cumulative reproduction decreased with age, respectively. However, mortality decreased and cumulative reproduction increased with age when organisms became adult. Peak sensitivity occurred in 4-d-old organisms exposed to Cu and Zn, while 2- to 3-d-old organisms were most sensitive to As and Se. Growth of D. magna over 21 d was not affected by the 12-h pulse of Cu, Zn, Se, or As given at any organism age. This indicates the recovery of the organisms after exposure termination. PMID:17571686

  20. Effects of bifenthrin on Daphnia magna during chronic toxicity test and the recovery test.

    PubMed

    Ye, Wei-Hong; Wen, Yue-Zhong; Liu, Wei-Ping; Wang, Zhong-Qiang

    2004-01-01

    The acute and chronic toxic effects of bifenthrin on Daphnia magna were studied. The results showed that 24 h-EC50, 48 h-LC50 and 96 h-LC50 of bifenthrin on D. magna were 3.24, 12.40 and 1.40 microg/L respectively. And the LOEC and NOEC of bifenthrin were 0.02 and 0.004 microg/L respectively. The recovery test of bifenthrin on Daphnia magna was presented. Daphnia magna (F0 generation) were exposed during 21 d to different bifenthrin concentrations. Offspring (animals from the first and third brood: F1 (1st) and F1 (3rd), respectively) were transferred to a free pesticide medium during a 21 d recovery period. In this recovery study, survival, growth, reproduction (mean total young per female, onset of reproduction and number broods per female) and the intrinsic rate of natural increase (r) were assessed as parameters. Reproduction such as number of young per female as well as length was still reduced in F1 (1st) generation daphnids from parentals (F0) exposed to the bifenthrin. However F, (3rd) individuals from parentals exposed to pesticide concentrations were able to restore reproduction when a recovery period of 21 d was allowed, but the length of F, (3rd) from parentals exposed to the 0.5 and 0.75 microg/L bifenthrin concentration was still significantly effected (P < 0.05). PMID:15559825

  1. Small scale mass culture of Daphnia magna Straus

    SciTech Connect

    Rees, J.T.; Oldfather, J.M.

    1980-02-01

    Daphnia magna Straus 1820 was raised on a defined medium in 4-liter flasks with controlled light intensity, temperature, and algal food species. Adult D. magna tolerated high levels of ammonia (up to 108 ..mu..M) at high pH (> 10), although at these levels parthenogenic reproduction may be inhibited. Scenedesmus quadricauda and Ankistrodesmus sp. were satisfactory food sources, and by utilizing Ankistrodesmus densities greater than one animal per ml were achieved. Maintaining the pH at about 7 to 8 seems to be important for successful D. magna culture.

  2. A comparison of the toxicity of 30 reference chemicals to Daphnia magna and Daphnia pulex

    SciTech Connect

    Lilius, H.; Haestbacka, T.; Isomaa, B.

    1995-12-01

    To determine whether significant differences exist in the sensitivity of different Daphnia species to toxicants, the acute toxicity of the first 30 MEIC (multicenter evaluation of in vitro cytotoxicity) reference chemicals was determined in two species of Daphnia: D. magna and D. pulex. Correlation and regression analysis of the EC50 data for immobilization showed a very good concordance (r = 0.97, slope = 1.02). A comparison between the EC50 data obtained for D. magna by two laboratories independently for the 50 MEIC chemicals also showed a good concordance (r = 0.93, slope = 0.91). In both comparisons the regression line did not differ significantly from the regression line for a 1:1 regression. The authors conclude that their study, including a set of reference chemicals, indicates that is no difference in the overall sensitivity of the two Daphnia species and the two clones of D. magna.

  3. Biokinetics and tolerance development of toxic metals in Daphnia magna.

    PubMed

    Tsui, Martin Tsz-Ki; Wang, Wen-Xiong

    2007-05-01

    Daphnia magna is widespread in many freshwater systems of temperate regions and frequently is used to test metal toxicity. Recently, studies have been performed to determine metal biokinetics and development of tolerance in this important zooplankton species. In the present paper, we review the recent progress in these areas and suggest possible directions for future studies. Substantial differences exist in aqueous uptake, dietary assimilation, and elimination of several metals (Cd, Se, Zn, Ag, Hg, and MeHg) by D. magna. The routes of uptake are metal-specific, with Se and MeHg being accumulated predominantly through diet. All metals except Ag can be biomagnified from algae to D. magna, providing that metal concentrations in algae and algal food density are relatively low. Methylmercury is biomagnified in all situations. As a route for metal elimination in D. magna, maternal transfer is especially important for Se, Zn, and MeHg. On the other hand, the effect of single-generation exposure to metals on D. magna is very different from multigeneration exposure, which often results in a significantly higher metal tolerance. Moreover, D. magna easily loses metal tolerance developed through long-term exposure. Recovery from metal stress can temporarily increase the sensitivity of D. magna to metal toxicity. Finally, metallothionein-like protein is responsible for minimizing metal toxicity in D. magna. The results inferred from these studies can be extrapolated to other aquatic invertebrates as well as to other pollutants in the aquatic environment. PMID:17521151

  4. Evaluation of the ultrasonic method for solubilizing Daphnia magna before liquid scintillation counting

    SciTech Connect

    Dauble, D.D.; Hanf, R.W. Jr.; Carlile, D.W.

    1984-11-01

    Adult Daphnia magna were exposed to /sup 14/C-labeled phenol and tissues analyzed for /sup 14/C uptake by three methods: (1) tissue solubilizer, (2) tissue solubilizer plus sonication, and (3) sonication alone. Analysis by liquid scintillation counting revealed that measurements of total activity among treatments were not significantly different (..cap alpha.. less than or equal to 0.10) at two count levels. Sonicated samples showed less variation than tissue samples that were solubilized. 5 references, 1 table.

  5. Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna

    PubMed Central

    Mattsson, Karin; Adolfsson, Karl; Ekvall, Mikael T.; Borgström, Magnus T.; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy; Prinz, Christelle N.

    2016-01-01

    Abstract Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter. PMID:27181920

  6. Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna.

    PubMed

    Mattsson, Karin; Adolfsson, Karl; Ekvall, Mikael T; Borgström, Magnus T; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy; Prinz, Christelle N

    2016-10-01

    Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter. PMID:27181920

  7. Effects of Microcystis aeruginosa on life history of water flea Daphnia magna

    NASA Astrophysics Data System (ADS)

    Liu, Liping; Li, Kang; Chen, Taoying; Dai, Xilin; Jiang, Min; Diana, James S.

    2011-07-01

    Cyanobacterial blooms in eutrophic freshwater systems are a worldwide problem, creating adverse effects for many aquatic organisms by producing toxic microcystins and deteriorating water quality. In this study, microcystins (MCs) in Microcystis aeruginosa, and Daphnia magna exposed to M. aeruginosa, were analyzed by HPLC-MS, and the effects of M. aeruginosa on D. magna were investigated. When D. magna was exposed to M. aeruginosa for more than 2 h, Microcystin-LR (MC-LR) was detected. When exposed to 1.5 × 106, 3 × 106, 0.75 × 107, and 1.5 × 107 cell/mL of M. aeruginosa for 96 h, average survival of D. magna for treatments were 23.33%, 33.33%, 13.33%, 16.67%, respectively, which were significantly lower than the average 100% survival in the control group ( P < 0.05). The adverse effects of M. aeruginosa on body length, time for the first brood, brood numbers, gross fecundity, lifespan, and population growth of D. magna were density-dependent. These results suggest that the occurrence of M. aeruginosa blooms could strongly inhibit the population growth of D. magna through depression of survival, individual growth and gross fecundity. In the most serious situations, M. aeruginosa blooms could undermine the food web by eliminating filter-feeding zooplankton, which would destroy the ecological balance of aquaculture water bodies.

  8. Silver Nanowire Exposure Results in Internalization and Toxicity to Daphnia Magna

    PubMed Central

    Scanlan, Leona D.; Reed, Robert B.; Loguinov, Alexandre V.; Antczak, Philipp; Tagmount, Abderrahmane; Aloni, Shaul; Nowinski, Daniel Thomas; Luong, Pauline; Tran, Christine; Karunaratne, Nadeeka; Pham, Don; Lin, Xin Xin; Falciani, Francesco; Higgins, Chris P.; Ranville, James F.; Vulpe, Chris D.; Gilbert, Benjamin

    2013-01-01

    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 physico-chemical 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 one-hour 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 (spICPMS) 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 (SEM) 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. PMID:24099093

  9. Toxicity of the cyanobacterium Cylindrospermopsis raciborskii to Daphnia magna.

    PubMed

    Nogueira, Isabel C G; Saker, Martin L; Pflugmacher, Stephan; Wiegand, Claudia; Vasconcelos, Vítor M

    2004-10-01

    The effect of two strains of Cylindrospermopsis raciborskii on the survivorship, somatic growth, and detoxification processes of juvenile Daphnia magna were investigated. Both strains of C. raciborskii (and also Ankistrodesmus falcatus, used as the control) were given to newborn D. magna at equivalent biovolumes. The survival curves for D. magna subjected to the two C. raciborskii treatments differed from those of the starved and fed treatments. After 48 h of exposure, the percentage of D. magna surviving after exposure to Cylin-A (a cylindrospermopsin-producing strain isolated from Australia) and Cylin-P (a non-cylindrospermopsin-producing strain isolated from Portugal) was 10.00% and 93.33%, respectively. The strain that produces cylindrospermopsin caused the greatest toxic effect in juvenile D. magna. Statistically significant differences in D. magna body size between the four treatments (Cylin-A, Cylin-P, A. falcatus, and starved) were detected after 48 h of exposure. The juvenile D. magna that received the two C. raciborskii treatments showed an increase in size (relative to their size at T(0)) of 2.54% and 38.14%, respectively. These values were statistically significantly different than those of the A. falcatus-fed control (55.54%) and the starved control (11.47%). In both C. raciborskii treatments there was a tendency for increased GST enzyme activities after 24 h of exposure. Cylindrospermopsin was detected (HPLC-MS/MS) in D. magna tissues after 24 and 48 h (0.025 and 0.02 ng animal(-)1, respectively). The results of this study indicate that C. raciborskii can affect the fitness and growth potential of juvenile D. magna. PMID:15352261

  10. Acute toxicity and QSAR of chlorophenols on Daphnia magna

    SciTech Connect

    Devillers, J.; Chambon, P.

    1986-10-01

    Chlorophenols which are released into natural waters from various industrial processes and from agricultural uses have been recognized as a group of chemical substances potentially hazardous to the aquatic environment. Therefore it is important to estimate their toxic impact on biota. Thus, the scope of this research was to obtain acute toxicity data for seventeen chlorophenols towards Daphnia magna and to explore the possibilities of deriving QSAR's (quantitative structure-activity relationship) from the above values.

  11. Rapid toxicity screening tests for aquatic biota. 1. Methodology and experiments with Daphnia magna

    SciTech Connect

    Janssen, C.R.; Persoone, G. )

    1993-04-01

    A promising new and rapid toxicity screening test was developed, the concept and principles of which are presented. The method consists of visual observation of in vivo inhibition of an enzymatic process, using a fluorescent substrate. Juvenile Daphnia magna was exposed to a toxicant dilution series for 1 h, after which the substrate was added and the enzymatic inhibition was observed visually, using a long-wave UV light. The 1-h EC50 results of 11 pure compounds are presented and compared to the conventional 24- and 48-h Daphnia magna EC50s. All 1-h fluorescence EC50s were of the same order of magnitude and correlated very well with the 24- and 48-h EC50s. The sensitivity and reproducibility of this cost-effective screening test were compared to those of the Microtox[reg sign] test. The scope for application and the potential of this new rapid toxicity screening test are evaluated.

  12. Betaproteobacteria Limnohabitans strains increase fecundity in the crustacean Daphnia magna: symbiotic relationship between major bacterioplankton and zooplankton in freshwater ecosystem.

    PubMed

    Peerakietkhajorn, Saranya; Kato, Yasuhiko; Kasalický, Vojtěch; Matsuura, Tomoaki; Watanabe, Hajime

    2016-09-01

    How symbioses between bacteria and aquatic animals influence food webs in freshwater ecosystems is a fundamental question in ecology. We investigated symbiosis between a crustacean zooplankton Daphnia magna and its dominant bacterial symbiont Limnohabitans, an abundant and globally distributed freshwater Betaproteobacteria. Aposymbiotic juvenile Daphnia were prepared and exposed to any of four Limnohabitans sp. - Limnohabitans strains DM1, 2KL-3, 2KL-7 and Limnohabitans planktonicus strain II-D5, all previously found in D. magna digestive tract or culture. Re-infected Daphnia were cultured until they produced the first clutch of juveniles. Limnohabitans strain DM1 and L. planktonicus strain II-D5 successfully re-infected Daphnia through single exposure at the first instar juvenile stage. In contrast to aposymbiotic Daphnia that produced non-viable juveniles, re-infected Daphnia produced viable juveniles and increased fecundity to levels of that of symbiotic Daphnia. Re-infected Daphnia did not increase their number of eggs nor growth rates. Limnohabitans strains 2KL-7 and 2KL-3 could not recover fecundity even in multiple exposures during culture. This study shows the functional evidence demonstrating that a single bacterium Limnohabitans regulates fecundity of the consumer Daphnia through symbiosis. Our results indicated that symbiotic relationship between major bacterioplankton and zooplankton is important for maintaining the population of zooplankton in freshwater ecosystems. PMID:26014379

  13. Characterizing the toxicity of pulsed selenium exposure to Daphnia magna.

    PubMed

    Hoang, Tham C; Klaine, Stephen J

    2008-03-01

    The acute toxicity of selenium (Se) to aquatic biota has been studied extensively for decades. However, most studies have used a constant concentration aqueous exposure of Se to an invertebrate species. Since constant concentration exposure of toxicants to invertebrates is unusual in the environment, episodic exposure or pulsed exposures may represent true risk to aquatic biota more accurately. This research was designed to characterize the toxicity effects of pulsed Se exposure to Daphnia magna. Selenium exposure was varied during a 21-d chronic toxicity test to examine the effects of exposure concentration, duration, and recovery on survival, growth, and reproduction of D. magna. While D. magna did not die during exposures, latent mortality was observed. Latent mortality increased with exposure concentration and duration. Hence, standard toxicity test using continuous exposures would underestimate Se toxicity. Risk assessment method using results of continuous exposure would underestimate risk of Se to biota. For double-pulse exposures, cumulative mortality on day 21 was higher when time interval between pulses was shorter. With the same total exposure time, continuous exposure caused higher toxicity than did pulsed exposures due to recovery and tolerance development in D. magna after earlier pulses. Growth and reproduction of surviving D. magna were not affected by pulsed Se exposure due to recovery of D. magna after removal of the pulses. Based on these results, risk assessment for Se should take latent effects and the effect of recovery in to account. PMID:18190947

  14. SMALL SCALE MASS CULTURE OF DAPHNIA MAGNA STRAUS

    SciTech Connect

    Rees, John T.; Oldfather, Joan M.

    1980-03-01

    Daphnia magna Straus 1820 was reared on a defined medium in 4-liter flasks under controlled conditions of light, temperature and species of algal food. Adult D. magna were found to be tolerant to high levels of ammonia, up to 108 {micro}M, at high pH (>10), although parthenogenic reproduction may be inhibited at these high levels. Scenedesmus quadricauda and Ankistrodesmus sp. were found to be satisfactory food sources. Densities of greater than one animal per ml in culture were attained utilizing Ankistrodesmus sp. as a food source at a pH of 7.7. Maintenance of pH at around 7-8 appears to be important to successful D. magna culture.

  15. Diofenolan induces male offspring production through binding to the juvenile hormone receptor in Daphnia magna.

    PubMed

    Abe, Ryoko; Toyota, Kenji; Miyakawa, Hitoshi; Watanabe, Haruna; Oka, Tomohiro; Miyagawa, Shinichi; Nishide, Hiroyo; Uchiyama, Ikuo; Tollefsen, Knut Erik; Iguchi, Taisen; Tatarazako, Norihisa

    2015-02-01

    Juvenile hormone (JH) and JH agonists have been reported to induce male offspring production in various daphnid species including Daphnia magna. We recently established a short-term in vivo screening assay to detect chemicals having male offspring induction activity in adult D. magna. Diofenolan has been developed as a JH agonist for insect pest control, but its male offspring induction activity in daphnids has not been investigated yet. In this study, we found that the insect growth regulator (IGR) diofenolan exhibited a potent male offspring induction activity at low ng/L to μg/L concentrations, as demonstrated by the short-term in vivo screening assay and the recently developed TG211 ANNEX 7 test protocol. A two-hybrid assay performed using the D. magna JH receptor confirmed that diofenolan had a strong JH activity. Global whole body transcriptome analysis of D. magna exposed to 10 ng/L diofenolan showed an up-regulation of JH-responsive genes and modulation of several genes involved in the ecdysone receptor signaling pathway. These results clearly demonstrate that diofenolan has strong JH activity and male offspring induction activity, and that a combination of modified standardized regulatory testing protocols and rapid in vitro and in vivo screening assays are able to identify potential endocrine disruptors in D. magna. The observation that diofenolan modulates multiple endocrine signaling pathways in D. magna suggests that further investigation of potential interference with growth, development and reproduction is warranted. PMID:25506888

  16. Synthesis, characterization and toxicological evaluation of Cr₂O₃ nanoparticles using Daphnia magna and Aliivibrio fischeri.

    PubMed

    Puerari, Rodrigo Costa; da Costa, Cristina H; Vicentini, Denice S; Fuzinatto, Cristiane F; Melegari, Silvia P; Schmidt, Éder C; Bouzon, Zenilda L; Matias, William G

    2016-06-01

    Chromium III oxide (Cr2O3) nanoparticles (NPs) are used in pigments for ceramics, dyes, paints and cosmetics. However, few studies addressing the toxic potential of these NPs have been reported in the literature. Thus, this research aimed to evaluate the acute and chronic effects of Cr2O3 NPs through acute toxicity tests with Daphnia magna and Aliivibrio fischeri and chronic toxicity tests with Daphnia magna. Cr2O3 NPs were synthesized by the sol-gel method and characterized through TEM, X-Ray diffraction (XRD), zeta potential (ZP) and surface area analysis. In the acute toxicity tests the EC(50,48h) value obtained with D. magna was 6.79 mg L(-1) and for A. fischeri the EC(50,15min) value was 16.10 mg L(-1) and the EC(50,30min) value was 12.91 mg L(-1). Regarding the chronic toxicity tests with D. magna, effects on longevity (OEC=1.00 mg L(-1)), reproduction (OEC=1.00 mg L(-1)) and growth (OEC=0.50 mg L(-1)) were observed. On the SEM and TEM images, ultrastructural alterations in the organelles of exposed organisms were also observed. Thus, toxicological studies with NPs are of great importance in order to reduce the risk of environmental contamination. PMID:26890188

  17. Purification and studies on characteristics of cholinesterases from Daphnia magna *

    PubMed Central

    Yang, Yan-xia; Niu, Li-zhi; Li, Shao-nan

    2013-01-01

    Due to their significant value in both economy and ecology, Daphnia had long been employed to investigate in vivo response of cholinesterase (ChE) in anticholinesterase exposures, whereas the type constitution and property of the enzyme remained unclear. A type of ChE was purified from Daphnia magna using a three-step procedure, i.e., Triton X-100 extraction, ammonium sulfate precipitation, and diethylaminoethyl (DEAE)-Sepharose™-Fast-Flow chromatography. According to sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), molecular mass of the purified ChE was estimated to be 84 kDa. Based on substrate studies, the purified enzyme preferred butyrylthiocholine iodide (BTCh) [with maximum velocity (V max)/Michaelis constant (K m)=8.428 L/(min·mg protein)] to acetylthiocholine iodide (ATCh) [with V max/K m=5.346 L/(min·mg protein)] as its substrate. Activity of the purified enzyme was suppressed by high concentrations of either ATCh or BTCh. Inhibitor studies showed that the purified enzyme was more sensitive towards inhibition by tetraisopropylpyrophosphoramide (iso-OMPA) than by 1,5-bis(4-allyldimethylammoniumphenyl) pentan-3-one dibromide (BW284C51). Result of the study suggested that the purified ChE was more like a type of pseudocholinesterase, and it also suggested that Daphnia magna contained multiple types of ChE in their bodies. PMID:23549850

  18. Effect of pulse frequency and interval on the toxicity of chlorpyrifos to Daphnia magna.

    PubMed

    Naddy, R B; Klaine, S J

    2001-11-01

    Due to the episodic nature in which organisms are exposed to non-point source pollutants, it is necessary to understand how they are affected by pulsed concentrations of contaminants. This is essential, as standard toxicity tests may not adequately simulate exposure scenarios for short-lived hydrophobic compounds, such as chlorpyrifos (CPF), a broad-spectrum organophosphate insecticide. Studies were conducted with 7-day old Daphnia magna for 7 days to evaluate the effect of pulse frequency and interval among multiple CPF exposures. Daphnids were exposed to a total exposure of either 12 h at 0.5 microg/l or 6 h at 1.0 microg/l nominal CPF, respectively, in all studies. For interval studies, D. magna were exposed to two pulses of CPF at each concentration, with 0-96-h intervals between pulses. For frequency studies, D. magna were exposed to each CPF concentration altering the pulse scheme by decreasing the exposure duration but increasing the number of pulses, keeping the total exposure time the same. The pulse interval between multiple pulses in these experiments was 24 h. Our results suggest that D. magna can withstand an acutely lethal CPF exposure provided that there is adequate time for recovery between exposures. PMID:11680745

  19. Accumulation and Inactivation of Avian Influenza Virus by the Filter-Feeding Invertebrate Daphnia magna

    PubMed Central

    Borchardt, Mark A.; Spencer, Susan K.

    2013-01-01

    The principal mode of avian influenza A virus (AIV) transmission among wild birds is thought to occur via an indirect fecal-oral route, whereby individuals are exposed to virus from the environment through contact with virus-contaminated water. AIV can remain viable for an extended time in water; however, little is known regarding the influence of the biotic community (i.e., aquatic invertebrates) on virus persistence and infectivity in aquatic environments. We conducted laboratory experiments to investigate the ability of an aquatic filter-feeding invertebrate, Daphnia magna, to accumulate virus from AIV-dosed water under the hypothesis that they represent a potential vector of AIV to waterfowl hosts. We placed live daphnids in test tubes dosed with low-pathogenicity AIV (H3N8 subtype isolated from a wild duck) and sampled Daphnia tissue and the surrounding water using reverse transcription-quantitative PCR (RT-qPCR) at 3- to 120-min intervals for up to 960 min following dosing. Concentrations of viral RNA averaged 3 times higher in Daphnia tissue than the surrounding water shortly after viral exposure, but concentrations decreased exponentially through time for both. Extracts from Daphnia tissue were negative for AIV by cell culture, whereas AIV remained viable in water without Daphnia present. Our results suggest daphnids can accumulate AIV RNA and effectively remove virus particles from water. Although concentrations of viral RNA were consistently higher in Daphnia tissue than the water, additional research is needed on the time scale of AIV inactivation after Daphnia ingestion to fully elucidate Daphnia's role as a potential vector of AIV infection to aquatic birds. PMID:24038705

  20. Effect of lindane on the clearance rate of daphnia magna

    PubMed

    Hartgers; Heugens; Deneer

    1999-05-01

    The impact of the insecticide lindane (gamma-hexachlorocyclohexane) on the clearance rate (CR) of Daphnia magna was investigated using artificial beads. CR (24-h EC50: 65 &mgr;g L-1) was found to be a more sensitive endpoint than acute lethality for D. magna (48-h LC50: 516 &mgr;g L-1). The onset of the effect was rapid; after 2 h of exposure to approximately 241 &mgr;g L-1 of lindane a significant decrease in CR was observed. Daphnids recovered rapidly after transfer to clean water; after 24 h of exposure to approximately 250 &mgr;g L-1 lindane, transfer into clean water resulted in recovery to 80% of control levels within 2 h and complete recovery within 24 h. PMID:10227859

  1. Chronic toxicity of biphenyl to Daphnia magna Straus

    SciTech Connect

    Gersich, F.M.; Bartlett, E.A.; Murphy, P.G.; Milazzo, D.P. )

    1989-09-01

    The US Environmental Protection Agency (EPA) issued a final test rule (1985) for biphenyl on the authority of Section 4(a) of the Toxic Substances Control Act (TSCA). Contained within this rule was the requirement for generating chronic daphnid toxicity data for biphenyl. Biphenyl is used primarily to produce dye carriers, heat-transfer fluids and alkylated biphenyls. The acute toxicity of biphenyl to Daphnia magna has been reported. The 48-hr LC50 values were 4.7 and 2.1 mg/L, respectively. To date, the chronic toxicity of biphenyl to fish and aquatic invertebrates has not been investigated. The objective of this study was to determine the chronic toxicity of biphenyl to D. magna. The daphnid chronic toxicity test is designed to estimate the maximum acceptable toxicant concentration (MATC). The MATC is defined as the concentration falling between the highest concentration showing no effect and the next higher concentration showing a toxic effect when compared to the controls.

  2. Statistical validation of structured population models for Daphnia magna

    PubMed Central

    Adoteye, Kaska; Banks, H.T.; Cross, Karissa; Eytcheson, Stephanie; Flores, Kevin B.; LeBlanc, Gerald A.; Nguyen, Timothy; Ross, Chelsea; Smith, Emmaline; Stemkovski, Michael; Stokely, Sarah

    2016-01-01

    In this study we use statistical validation techniques to verify density-dependent mechanisms hypothesized for populations of Daphnia magna. We develop structured population models that exemplify specific mechanisms, and use multi-scale experimental data in order to test their importance. We show that fecundity and survival rates are affected by both time-varying density-independent factors, such as age, and density-dependent factors, such as competition. We perform uncertainty analysis and show that our parameters are estimated with a high degree of confidence. Further, we perform a sensitivity analysis to understand how changes in fecundity and survival rates affect population size and age-structure. PMID:26092608

  3. Effects of metal salt mixtures on Daphnia magna reproduction

    SciTech Connect

    Biesinger, K.E.; Christensen, G.M.; Fiandt, J.T.

    1986-02-01

    Three binary metal experiments were conducted using a complete block design; testing the chlorides of Cd, Hg, and Zn individually and in combinations of Cd-Hg, Cd-Zn, and Zn-Hg on Daphnia magna reproduction. These mixtures were tested at one-half, once, and twice the 16% reproductive impairment concentration previously determined for individual metals. The Cd-Hg, Cd-Zn, and Zn-Hg mixtures all showed significant reductions in reproduction at concentrations where the metal salts alone caused no significant effect.

  4. The chronic toxicity of CuO nanoparticles and copper salt to Daphnia magna.

    PubMed

    Adam, Nathalie; Vakurov, Alexander; Knapen, Dries; Blust, Ronny

    2015-01-01

    In this study, the effects of CuO nanoparticles and CuCl2·2H2O were tested on Daphnia magna under chronic exposure scenarios. During a 21-day exposure to the nanoparticles and salt, the reproduction was followed by a daily count of the number of offspring. After the exposure, the adult Daphnia length and uptake of copper was measured. The dissolved, nanoparticle and aggregated fractions were distinguished in the exposure medium. The results showed that only a small fraction of the nanoparticles dissolved, while the majority of the particles formed large aggregates (>450 nm). The dissolved fraction of the nanoparticles corresponded with the dissolved fraction of the copper salt. The effects of the nanoparticles (reproduction EC10: 0.546 mg Cu/l, EC20: 0.693 mg Cu/l, EC50: 1.041 mg Cu/l) on reproduction and length were much lower than the effects of the copper salts (reproduction EC10: 0.017 mg Cu/l, EC20: 0.019 mg Cu/l, EC50: 0.022 mg Cu/l). Based upon total body analysis, the Daphnia copper concentration appeared much higher when exposed to the nanoparticles than when exposed to the salt. These combined results indicate that the toxicity of CuO nanoparticles to D. magna is caused by copper ions formed during dissolution of the nanoparticles in the exposure medium. PMID:25464278

  5. Chromium toxicity on two linked trophic levels. I. Effects of contaminated algae on Daphnia magna.

    PubMed

    Gorbi, G; Corradi, M G

    1993-02-01

    The effects of feeding Daphnia magna on algae (Scenedesmus acutus) pretreated with different concentrations of Cr(VI) were studied. A positive effect on growth and newborn production rate was observed in the daphnids fed on algae exposed to 1 mg/liter Cr(VI). Fecundity and growth were drastically reduced in daphnids fed on algae exposed to 10 mg/liter Cr(VI). Since the algae, cultured in the presence of these two Cr(VI) concentrations, supplied daphnids with similar amounts of chromium, the observed effects on the population dynamics of D. magna were attributed more to alterations of the nutritional value of the algal food, due to the Cr treatment, than to a toxic effect of the metal. PMID:7682919

  6. Exploring methods for compositional and particle size analysis of noble metal nanoparticles in Daphnia magna.

    PubMed

    Krystek, Petra; Brandsma, Sicco; Leonards, Pim; de Boer, Jacob

    2016-01-15

    The identification and quantification of the bioaccumulation of noble metal engineered nanoparticles (ENPs) by aquatic organisms is of great relevance to understand the exposure and potential toxicity mechanisms of nanoscale materials. Four analytical scenarios were investigated in relation to various sized and composed noble metal (gold (Au), platinum (Pt) and silver (Ag)) ENPs during acute, short-term exposure of Daphnia (D.) magna. Next to the total elemental quantification of absorbed ENPs by D. magna, especially information on the size and particle distribution of ENPs in D. magna is of relevance. Dissolution of the exposed biological material prior to measurement by asymmetric flow field flow fractionation coupled to inductively coupled plasma mass spectrometry (AF4-ICPMS) is challenging because the ENPs must stay stable regarding to particle size and composition. Next to dissolution of exposed D. magna by tetra methyl ammonium hydroxide (TMAH), a new enzymatic dissolution approach was explored by using trypsin. The presence of various sized and composed ENPs has been confirmed by AF4-ICPMS but the chosen dissolution medium was crucial for the results. TMAH and trypsin led to comparable results for medium-sized (50nm) noble metals ENPs in exposed D. magna. But it was also shown that the dissolution of biological materials with smaller (<5nm) ENPs led to different results in particle size and elemental concentration depending on the selected dissolution medium. A significant uptake of Au and Pt ENPs by D. magna or adsorption to particles occurred because only 1-5% of the exposed ENPs remained in the exposure medium. PMID:26592609

  7. Bioavailability of sediment-associated Cu and Zn to Daphnia magna.

    PubMed

    Gillis, P L; Wood, C M; Ranville, J F; Chow-Fraser, P

    2006-05-25

    Exposures to mining-impacted, field-collected sediment (Clear Creek, CO, USA) contaminated with Cu (2.4 mg/g) and Zn (5.2 mg/g) were acutely toxic to juvenile Daphnia magna. Dissolved Cu and Zn in the overlying water (sediment+reference water) were at levels that could cause acute toxicity. To reduce dissolved metals below toxic levels, the sediment was repeatedly rinsed to remove any easily mobilized metals. Washing the sediment reduced dissolved Cu by 60% and Zn by 80%. D. magna exposed to washed sediment experienced higher survival (95%) compared to those exposed to the original sediment (<50%). Cu and Zn that remained associated with suspended sediment after washing were not bioavailable, since survival and tissue metal concentrations in D. magna exposed to both filtered (>0.45 microm) and unfiltered overlying water were statistically similar. Multiple regression analysis indicated that only dissolved Cu significantly contributed to mortality of D. magna whereas particulate Cu, particulate Zn, and dissolved Zn did not. Regression analysis on a combined dataset from all Clear Creek exposures (washed and unwashed), revealed a significant (p < 0.0001, r(2) = 0.76) relationship between the concentration of dissolved copper in the overlying water and the mortality of exposed Daphnia, yielding an estimated LC50 of 26 microg/L dissolved copper (hardness approximately 140 mg/L). The results of this study indicate that if the sediment of Clear Creek was subjected to a resuspension event that there would be a significant efflux of metals from the sediment into the water column, resulting in potentially toxic levels in the water column. PMID:16488492

  8. TALEN-mediated homologous recombination in Daphnia magna

    PubMed Central

    Nakanishi, Takashi; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

    2015-01-01

    Transcription Activator-Like Effector Nucleases (TALENs) offer versatile tools to engineer endogenous genomic loci in various organisms. We established a homologous recombination (HR)-based knock-in using TALEN in the crustacean Daphnia magna, a model for ecological and toxicological genomics. We constructed TALENs and designed the 67 bp donor insert targeting a point deletion in the eyeless mutant that shows eye deformities. Co-injection of the TALEN mRNA with donor DNA into eggs led to the precise integration of the donor insert in the germ line, which recovered eye deformities in offspring. The frequency of HR events in the germ line was 2% by using both plasmid and single strand oligo DNA with 1.5 kb and 80 nt homology to the target. Deficiency of ligase 4 involved in non-homologous end joining repair did not increase the HR efficiency. Our data represent efficient HR-based knock-in by TALENs in D. magna, which is a promising tool to understand Daphnia gene functions. PMID:26674741

  9. Disturbances in energy metabolism of Daphnia magna after exposure to tebuconazole.

    PubMed

    Sancho, E; Villarroel, M J; Andreu, E; Ferrando, M D

    2009-03-01

    This study was conducted to investigate the change of some biochemical parameters in the aquatic invertebrate Daphnia magna following exposure to the fungicide tebuconazole and to determine the most sensitive biomarker among the ones tested in this species. Four biochemical biomarkers (protein, glycogen, lipids and caloric content) were correlated with feeding behaviour studies of D. magna after fungicide exposure. Juveniles of D. magna were exposed to four sublethal concentrations of tebuconazole (0.41, 0.52, 0.71 and 1.14 mgL(-1)) for 5d. Daphnid samples were taken from each test and control group at 24, 48, 72, 96 and 120 h after the start of the experiment. Tebuconazole EC(50) values were calculated on D. magna in our laboratory as 56.83 and 40.10 mgL(-1) at 24 and 48 h, respectively. Results showed that daphnid energy content decreased as tebuconazole concentration increased, especially after 96-120 h of exposure to 0.52 mgL(-1) and higher fungicide concentrations. The data suggest that tebuconazole is moderately toxic to D. magna but also that it seriously impairs the metabolic functions, resulting in alterations in biochemical constituents. In the D. magna feeding study, algae feeding rates were inhibited after fungicide exposure. Such findings indicate the importance of feeding studies in laboratory toxicity test as well as their relationship with others studies. The results emphasize the importance of considering different kind of biomarkers to identify and evaluate the biological effect of a fungicide in the aquatic environment. Although the biochemical biomarkers used resulted good indicators of tebuconazole toxicity, feeding rates in D. magna decreased after only 5h exposure to the fungicide resulting in the most sensitive parameter of daphnid fungicide exposure. PMID:19135699

  10. The influence of benthic fish bioturbation on cadmium bioavailability to Daphnia magna

    SciTech Connect

    Wall, S.B.; Isely, J.J.; La Point, T.W.

    1994-12-31

    The authors are interested in how benthic fish bioturbation of contaminated sediments influences bioaccumulation into planktonic and, ultimately, nektonic organisms. They performed a series of exposures with cadmium-spiked sediment, 1 {mu}g/g nominal concentration, and koi carp Cyprinus carpio. Daphnia magna were placed in exposure aquaria with and without carp for six days and bioaccumulation after 48 h was measured. Preliminary results indicate that carp increased total suspended solids from 0.0 mg/L to 44.4 mg/L and mean total cadmium water concentrations, 1.4 {mu}g/L and 2.8 {mu}g/L, without and with fish, respectively. However, body burdens of Daphnia magna did not reflect the water concentration trend. Mean Cd residues of daphnids exposed without fish, 9.377 {mu}g/g, were not statistically different from those in the with-fish exposure, 8.348 {mu}g/g. Similarity in daphnid body burdens was probably due to cadmium binding with suspended sediment particles and dissolved organic carbon in the exposure chambers, therefore minimizing Cd bioavailability to D. magna. The present focus is on determining the bioavailable cadmium concentration.

  11. Development of a Daphnia magna DNA microarray for evaluating the toxicity of environmental chemicals.

    PubMed

    Watanabe, Hajime; Takahashi, Eri; Nakamura, Yuko; Oda, Shigeto; Tatarazako, Norihisa; Iguchi, Taisen

    2007-04-01

    Toxic chemical contaminants have a variety of detrimental effects on various species, and the impact of pollutants on ecosystems has become an urgent issue. However, the majority of studies regarding the effects of chemical contaminants have focused on vertebrates. Among aquatic organisms, Daphnia magna has been used extensively to evaluate organism- and population-level responses of invertebrates to pollutants in acute toxicity or reproductive toxicity tests. Although these types of tests can provide information concerning hazardous concentrations of chemicals, they provide no information about their mode of action. Recent advances in molecular genetic techniques have provided tools to better understand the responses of aquatic organisms to pollutants. In the present study, we adapted some of the techniques of molecular genetics to develop new tools, which form the basis for an ecotoxicogenomic assessment of D. magna. Based on a Daphnia expressed sequence tag database, we developed an oligonucleotide-based DNA microarray with high reproducibility. The DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to several different chemicals: Copper sulfate, hydrogen peroxide, pentachlorophenol, or beta-naphthoflavone. Exposure to these chemicals resulted in characteristic patterns of gene expression that were chemical-specific, indicating that the Daphnia DNA microarray can be used for classification of toxic chemicals and for development of a mechanistic understanding of chemical toxicity on a common freshwater organism. PMID:17447551

  12. Use of daphnia magna to assess potentially contaminated buildings. Final report, April 1990-March 1991

    SciTech Connect

    Haley, M.V.; Kurnas, C.W.

    1992-06-01

    Random concrete core samples taken from a loading dock were used in determining the toxicity of concrete to Daphnia magna. The cores were ground to powder and analyzed for volatiles and chemical agents before being subjected to aquatic toxicology studies using Daphnia magna. Particle size, pH, and ion exchange mechanisms were investigated as par of methodology development. No effects were observed in daphnia exposed to concrete concentrations up to 4000 mg/L after the pH was adjusted. It was determined that an ion exchange reaction between sodium bicarbonate and concrete caused the water hardness to drop. Concrete spiked with sodium lauryl sulfate, copper sulfate, and Beta-aminoethylarylthiosulfonate were investigated to determine if concrete would alter the toxicity. The resulting EC50s were 17.2, 1.42, and 17.3 mg/L, respectively. The copper sulfate toxicity was reduced by two orders of magnitude. The changes in sodium lauryl sulfate and Beta-aminoethylarylthiosulfonate were not significant.

  13. Influence of food, aquatic humus, and alkalinity on methylmercury uptake by Daphnia magna

    SciTech Connect

    Monson, B.A.; Brezonik, P.L.

    1999-03-01

    Six-day-old Daphnia magna were exposed to low concentrations of methylmercury (MeHg) in synthetic freshwater and synthetic food. Uptake kinetics were determined in 24- to 72-h experiments, measuring both the loss of Hg from water and accumulation in D. magna. Dose-uptake response was linear for MeHg concentrations up to 4.0 ng/L; an initial concentration of 2.0 ng/L was used when other factors were varied. Concentrations of total Hg and MeHg in water and D. magna were measured in treatments with varied hardness and alkalinity, aquatic humus (AH), and food spiked with MeHg versus water spiked with MeHg. Uptake rate coefficients were derived from two versions of a first-order, two-compartment model. The first version assumed constant MeHg concentration; the second accounted for changing MeHg concentration in water over time. Both models accounted for a nonzero starting concentration of MeHg in plankton. Fitted rate coefficients were higher for the second model than the first: the uptake coefficient (k{sub u}) was nine times higher; the depuration coefficient (k{sub d}) was twice as high. Assuming a constant MeHg concentration for a one-time spike thus underestimated the rate coefficient. The source of MeHg was compared by exposing D. magna for 48 h to MeHg at 2 ng/L in food or water. Daphnia magna accumulated significantly more inorganic Hg (i.e., Hg{sup 2+}) from spiked food than from spiked water, but accumulation of MeHg was the same from both sources. A similar response was found when D. magna were exposed to a lake water extraction of AH at concentrations of C at 3 and 10 mg/L. At the higher AH concentration, total Hg in daphnids was higher, but MeHg was lower, suggesting that AH was a source of inorganic Hg but reduced the bioavailability of MeHg. Exposure of D. magna to MeHg at 2 ng/L in hard or soft water adjusted to pH 6.7 showed no significant difference in MeHg uptake, supporting an argument that hardness and alkalinity per se do not affect MeHg uptake by

  14. Daphnia magna feeding behavior after exposure to tetradifon and recovery from intoxication.

    PubMed

    Villarroel, M J; Ferrando, M D; Sancho, E; Andreu, E

    1999-09-01

    The feeding behavior of the cladocera Daphnia magna subjected to a short-term exposure to the acaricide tetradifon (4-chlorophenyl 2,4, 5-trichlorophenyl sulfone) was studied. The experiments were performed using the unicellular algae Nannochloris oculata at a density of 5x10(5) cells/ml as food for the organisms. In a first experiment, three generations (F0, F1, and F3) of the daphnids were exposed to sublethal levels of tetradifon (0.1, 0.18, 0.22, and 0.44 mg/l) and the effect of the toxicant on filtration and ingestion rates was determined. Rates of filtration and ingestion of D. magna declined in the three generations studied with increasing toxicant concentrations; however, toxicant effect was greater in daphnids from generations F1 and F3 than in those from the parental generation F0. A second experiment was conducted in order to evaluate whether animals of a first (1) or third (F3) generation coming from parental daphnids (F0) previously exposed to those pesticide concentrations exhibited any alteration in feeding behavior when transferred to clean water (recovery period). The results indicated that the feeding rates of D. magna generations F1 and F3 were still affected during the recovery period but to a less degree. The effective tetradifon concentrations D. magna at which feeding rates were reduced to 50% that of controls (EC(50)) were also calculated. PMID:10499987

  15. Reproduction recovery of the crustacean Daphnia magna after chronic exposure to ibuprofen.

    PubMed

    Hayashi, Yuya; Heckmann, Lars-Henrik; Callaghan, Amanda; Sibly, Richard M

    2008-05-01

    In mammals, the pharmaceutical ibuprofen (IB), a non-steroidal anti-inflammatory drug, primarily functions by reversibly inhibiting the cyclooxygenase (COX) pathway in the synthesis of eicosanoids (e.g. prostaglandins). Previous studies suggest that IB may act in a similar manner to interrupt production of eicosanoids reducing reproduction in the model crustacean Daphnia magna. On this basis withdrawal of IB should lead to the recovery of D. magna reproduction. Here we test whether the effect of IB is reversible in D. magna, as it is in mammals, by observing reproduction recovery following chronic exposure. D. magna (5-days old) were exposed to a range of IB concentrations (0, 20, 40 and 80 mg l(-1)) for 10 days followed by a 10 day recovery period in uncontaminated water. During the exposure period, individuals exposed to higher concentrations produced significantly fewer offspring. Thereafter, IB-stressed individuals produced offspring faster during recovery, having similar average population growth rates (PGR) (1.15-1.28) to controls by the end of the test. It appears that maternal daphnids are susceptible to IB during egg maturation. This is the first recorded recovery of reproduction in aquatic invertebrates that suffered reproductive inhibition during chronic exposure to a chemical stressor. Our results suggest a possible theory behind the compensatory fecundity that we referred to as 'catch-up reproduction'. PMID:18214676

  16. Impact of imidacloprid on Daphnia magna under different food quality regimes.

    PubMed

    Ieromina, Oleksandra; Peijnenburg, Willie J G M; de Snoo, Geert; Müller, Jutta; Knepper, Thomas P; Vijver, Martina G

    2014-03-01

    Aquatic ecosystems are characterized by fluctuating conditions that have direct effects on aquatic communities but also indirect influences such as changing the toxicity of chemicals. Because the effect of food quality on pesticide toxicity has rarely been studied, in the present study Daphnia magna juveniles supplied with 4 different food quality levels were exposed to a range of imidacloprid concentrations for 21 d. Food quality was expressed as carbon:phosphorus ratios of algae Pseudokirchneriella subcapitata (C:P 35, C:P 240, C:P 400, and C:P 1300). Survival, growth rates, and reproduction of D. magna were monitored, and the combined effects of imidacloprid exposure and the phosphorus content of algae were analyzed. A stronger effect on survival was observed at the P-deficient diet (C:P 1300), confirmed by lower 10% effect concentration (EC10) values at days 7, 9, 15, and 21 compared with diets with higher phosphorus contents. Similarly, the growth rate was reduced when D. magna were supplied with algae of low phosphorus content at imidacloprid exposure conditions. The highest reproductive output was observed for D. magna fed the optimal phosphorus diet (C:P 240), both at control and exposed conditions. Poor food quality increased the sensitivity of nontarget species to pesticide exposure, potentially leading to an underestimation of adverse effects on aquatic communities in the field. PMID:24288231

  17. Chronic toxicity of dietary copper to Daphnia magna.

    PubMed

    De Schamphelaere, K A C; Forrez, I; Dierckens, K; Sorgeloos, P; Janssen, C R

    2007-03-30

    There is a growing concern that dietborne metal toxicity might be important in aquatic ecosystems. However, the science behind this matter is insufficiently developed to explicitly and accurately account for this in metal regulation or risk assessment. We investigated the effects of a chronic exposure of Daphnia magna to an elevated level of Cu (3000 microg Cu/g dry wt) in their diet (the green alga Pseudokirchneriella subcapitata). Compared to daphnids fed with P. subcapitata containing a background of 10.6 microg Cu/g dry wt, daphnids fed for 21 days with this Cu-contaminated food accumulated a total copper body burden of 325 microg Cu/g dry wt, which is about 30-fold higher than the control body burden of 12.1 microg/g dry wt. The exposed daphnids experienced a 38% reduction of growth (measured as final dry body weight), a 50% reduction of reproduction (total number of juveniles produced per daphnid), and only produced three broods versus four broods by the control daphnids. Unlike most other studies, we were able to demonstrate that these effects were most likely not due to a reduced nutritional quality of the food, based on C:P ratios and fatty acid content and composition of the Cu-contaminated algae. Life-history analysis showed that time to first brood was not affected by dietary Cu, while the second and third broods were significantly delayed by 0.7 and 1.5 days, respectively. On the other hand, brood sizes of all three broods were significantly lower in Cu exposed daphnids, i.e. by 32-55%. The variety of effects observed suggest the possible, and perhaps simultaneous, involvement of several toxicity mechanisms such as increased metabolic cost, reduced energy acquisition (potentially via inhibition of digestive enzyme activity), targeted inhibition of reproduction (potentially via inhibition of vitellogenesis), and/or direct inhibition of molting. Further research is needed to differentiate between these postulated mechanisms of dietary Cu toxicity and to

  18. Daphnia magna ecotoxicogenomics provides mechanistic insights into metal toxicity.

    PubMed

    Poynton, Helen C; Varshavsky, Julia R; Chang, Bonnie; Cavigiolio, Giorgio; Chan, Sarah; Holman, Patricia S; Loguinov, Alexandre V; Bauer, Darren J; Komachi, Kelly; Theil, Elizabeth C; Perkins, Edward J; Hughes, Owen; Vulpe, Chris D

    2007-02-01

    Toxicogenomics has provided innovative approaches to chemical screening, risk assessment, and predictive toxicology. If applied to ecotoxicology, genomics tools could greatly enhance the ability to understand the modes of toxicity in environmentally relevant organisms. Daphnia magna, a small aquatic crustacean, is considered a "keystone" species in ecological food webs and is an indicator species for toxicant exposure. Our objective was to demonstrate the potential utility of gene expression profiling in ecotoxicology by identifying novel biomarkers and uncovering potential modes of action in D. magna. Using a custom D. magna cDNA microarray, we identified distinct expression profiles in response to sublethal copper, cadmium, and zinc exposures and discovered specific biomarkers of exposure including two probable metallothioneins, and a ferritin mRNA with a functional IRE. The gene expression patterns support known mechanisms of metal toxicity and reveal novel modes of action including zinc inhibition of chitinase activity. By integrating gene expression profiling into an environmentally important organism, this study provides experimental support for the utility of ecotoxicogenomics. PMID:17328222

  19. Effect of metals on Daphnia magna and cladocerans representatives of the Argentinean fluvial littoral.

    PubMed

    Luciana, Regaldo; Reno, Ulises; Gervasio, Susana; Horacio, Troiani; Gagneten, Ana María

    2014-07-01

    Chronic toxicity tests were conducted to assess the effect of Cu, Cr and Pb on Moinodaphnia macleayi and Ceriodaphnia dubia -two cladoceran species from the Argentinian Fluvial Littoral Zone (AFLZ)- and Daphnia magna -an holarctic species-. The specimens were exposed to three concentrations of each metal. As endpoints, the number of living and dead organisms, molts, neonates released, and the age of first reproduction were recorded. Chronic assays showed that Cu significantly affected the analyzed life history traits in the three species. The lowest Pb and Cr concentrations did not affect survival, molting or fecundity in D. magna. Conversely, in M. macleayi and C. dubia, survival, molting and fecundity showed highly significant differences in all the concentrations tested compared to control assay. The present study stresses the importance of using biological parameters as bioindicators, as well as the study species from the Southern Hemisphere to assess metal pollution. PMID:25004754

  20. Differential oxidative stress of octahedral and cubic Cu2O micro/nanocrystals to Daphnia magna.

    PubMed

    Fan, Wenhong; Wang, Xiaolong; Cui, Minming; Zhang, Dongfeng; Zhang, Yuan; Yu, Tao; Guo, Lin

    2012-09-18

    This study attempts to understand the impact of different shapes of an individual micro/nanomaterial on their biotoxicities to aquatic organisms. Two differently shaped Cu(2)O micro/nanocrystals (cubes and octahedrons with side lengths of 900 nm) were exposed to Daphnia magna for 72 h, afterward several antioxidant biomarkers such as reactive oxygen species (ROS), catalase (CAT), total antioxidant capacity (T-AOC), and malondialdehyde (MDA) in D. magna were measured. We demonstrated the differential influences of two crystallographic Cu(2)O nanocrystals on the antioxidant process. Specifically, octahedral Cu(2)O nanocrystals showed a higher level of oxidative stress, possibly because of its larger surface area and higher reaction activity of the octahedron. The biomarker results further showed that the oxidative stress and antioxidant mechanism process involved three stages-antioxidant response, oxidation inhibition, and antioxidant inactivation. Furthermore, the accumulation of MDA was mainly responsible for the ROS-induced toxicity. PMID:22894800

  1. Effect of age on sensitivity of daphnia magna to cadmium, copper and cyanazine

    SciTech Connect

    Nebeker, A.V.; Cairns, M.A.; Onjukka, S.T.; Titus, R.H.

    1986-01-01

    Daphnia magna were exposed to cadmium, copper, and cyanazine to determine the relative sensitivities of several age groups: less than 4 h, less than 24 h, 1 d, 2 d, 3 d, 4 d, 5 d, and 6 d old. Mean cadmium 48-h EC50 values for each age group ranged from 23 to 164 micrograms/L. Mean copper EC50 values ranged from 6 to 18 micrograms/L. Cyanazine EC50 values ranged from 53 to 106 micrograms/L. The 1-d-old Daphnia mean EC50s were 48 and 49 micrograms/L for cadmium, 10 and 10 micrograms/L for copper and 84 and 86 microgram/L for cyanazine, respectively. These similar sensitivities indicate that older animals can be used in tests equally as well as younger animals, thus simplifying the recovery of daphnids in acute sediment toxicity tests.

  2. Behavioral and physiological changes in Daphnia magna when exposed to nanoparticle suspensions (titanium dioxide, nano-C60, and C60HxC70Hx)

    PubMed Central

    Lovern, Sarah B.; Strickler, J. Rudi; Klaper, Rebecca

    2008-01-01

    Little is known about the impact manufactured nanoparticles will have on aquatic organisms. Previously, we demonstrated that toxicity differs with nanoparticle type and preparation and observed behavioral changes upon exposure to the more lethal nanoparticle suspensions. In this experiment, we quantified these behavioral and physiological responses of Daphnia at sublethal nanoparticle concentrations. Titanium dioxide (TiO2) and fullerenes (nano-C60) were chosen for their potential use in technology. Other studies suggest that addition of functional groups to particles can affect their toxicity to cell cultures, but it is unknown if the same is true at the whole organism level. Therefore, a fullerene derivative, C60HxC70Hx, was also used to examine how functional groups affect Daphnia response. Using a high-speed camera, we quantified several behavior and physiological parameters including hopping frequency, feeding appendage and postabdominal curling movement, and heart rate. Nano-C60 was the only suspension to cause a significant change in heart rate. Both exposure to nano-C60 and C60HxC70Hx suspensions caused hopping frequency and appendage movement to increase. These results are associated with increased risk of predation and reproductive decline. They indicate that certain nanoparticle types may have impacts on population and food web dynamics in aquatic systems. PMID:17626453

  3. Daphnia magna transcriptome by RNA-Seq across 12 environmental stressors.

    PubMed

    Orsini, Luisa; Gilbert, Donald; Podicheti, Ram; Jansen, Mieke; Brown, James B; Solari, Omid Shams; Spanier, Katina I; Colbourne, John K; Rush, Douglas; Decaestecker, Ellen; Asselman, Jana; De Schamphelaere, Karel A C; Ebert, Dieter; Haag, Christoph R; Kvist, Jouni; Laforsch, Christian; Petrusek, Adam; Beckerman, Andrew P; Little, Tom J; Chaturvedi, Anurag; Pfrender, Michael E; De Meester, Luc; Frilander, Mikko J

    2016-01-01

    The full exploration of gene-environment interactions requires model organisms with well-characterized ecological interactions in their natural environment, manipulability in the laboratory and genomic tools. The waterflea Daphnia magna is an established ecological and toxicological model species, central to the food webs of freshwater lentic habitats and sentinel for water quality. Its tractability and cyclic parthenogenetic life-cycle are ideal to investigate links between genes and the environment. Capitalizing on this unique model system, the STRESSFLEA consortium generated a comprehensive RNA-Seq data set by exposing two inbred genotypes of D. magna and a recombinant cross of these genotypes to a range of environmental perturbations. Gene models were constructed from the transcriptome data and mapped onto the draft genome of D. magna using EvidentialGene. The transcriptome data generated here, together with the available draft genome sequence of D. magna and a high-density genetic map will be a key asset for future investigations in environmental genomics. PMID:27164179

  4. Daphnia magna transcriptome by RNA-Seq across 12 environmental stressors

    PubMed Central

    Orsini, Luisa; Gilbert, Donald; Podicheti, Ram; Jansen, Mieke; Brown, James B.; Solari, Omid Shams; Spanier, Katina I.; Colbourne, John K.; Rush, Douglas; Decaestecker, Ellen; Asselman, Jana; De Schamphelaere, Karel A.C.; Ebert, Dieter; Haag, Christoph R.; Kvist, Jouni; Laforsch, Christian; Petrusek, Adam; Beckerman, Andrew P.; Little, Tom J.; Chaturvedi, Anurag; Pfrender, Michael E.; De Meester, Luc; Frilander, Mikko J.

    2016-01-01

    The full exploration of gene-environment interactions requires model organisms with well-characterized ecological interactions in their natural environment, manipulability in the laboratory and genomic tools. The waterflea Daphnia magna is an established ecological and toxicological model species, central to the food webs of freshwater lentic habitats and sentinel for water quality. Its tractability and cyclic parthenogenetic life-cycle are ideal to investigate links between genes and the environment. Capitalizing on this unique model system, the STRESSFLEA consortium generated a comprehensive RNA-Seq data set by exposing two inbred genotypes of D. magna and a recombinant cross of these genotypes to a range of environmental perturbations. Gene models were constructed from the transcriptome data and mapped onto the draft genome of D. magna using EvidentialGene. The transcriptome data generated here, together with the available draft genome sequence of D. magna and a high-density genetic map will be a key asset for future investigations in environmental genomics. PMID:27164179

  5. Acute toxicity assessment of camphor in biopesticides by using Daphnia magna and Danio rerio

    PubMed Central

    Yim, Eun-Chae; Kim, Hyeon-Joe; Kim, Seong-Jun

    2014-01-01

    Objectives An ecofriendly alternative to chemical pesticides is bio-pesticides, which are derived from natural sources. The interest in bio-pesticides is based on the disadvantages associated with chemical pesticides. Methods We conducted acute toxicity assessments of camphor, a major component of bio-pesticides, by using Daphnia magna (D. magna) as well as assessed the morphological abnormalities that occurred in Danio rerio (D. rerio) embryos. Results The median effective concentration of camphor on D. magna after 48 hours was 395.0 μM, and the median lethal concentration on D. rerio embryos after 96 hours was 838.6 μM. The no observed effect concentration and predicted no effect concentration of camphor on D. magna, which was more sensitive than D. rerio, were calculated as 55.2 μM and 3.95 μM, respectively. Morphological abnormalities in D. rerio embryos exposed to camphor increased over time. Coagulation, delayed hatching, yolk sac edema, pericardial edema, and pigmentation of embryos mainly appeared between 24 and 48 hours. Further, symptoms of scoliosis and head edema occurred after 72 hours. In addition, bent tails, ocular defects and collapsed symptoms of fertilized embryonic tissue were observed after 96 hours. Conclusions The camphor toxicity results suggest that continuous observations on the ecosystem are necessary to monitor toxicity in areas where biological pesticides containing camphor are sprayed. PMID:25234414

  6. Obesogens beyond Vertebrates: Lipid Perturbation by Tributyltin in the Crustacean Daphnia magna

    PubMed Central

    Jordão, Rita; Casas, Josefina; Fabrias, Gemma; Campos, Bruno; Piña, Benjamín; Lemos, Marco F.L.; Soares, Amadeu M.V.M.; Tauler, Romà

    2015-01-01

    Background The analysis of obesogenic effects in invertebrates is limited by our poor knowledge of the regulatory pathways of lipid metabolism. Recent data from the crustacean Daphnia magna points to three signaling hormonal pathways related to the molting and reproductive cycles [retinoic X receptor (RXR), juvenile hormone (JH), and ecdysone] as putative targets for exogenous obesogens. Objective The present study addresses the disruptive effects of the model obesogen tributyltin (TBT) on the lipid homeostasis in Daphnia during the molting and reproductive cycle, its genetic control, and health consequences of its disruption. Methods D. magna individuals were exposed to low and high levels of TBT. Reproductive effects were assessed by Life History analysis methods. Quantitative and qualitative changes in lipid droplets during molting and the reproductive cycle were studied using Nile red staining. Lipid composition and dynamics were analyzed by ultra-performance liquid chromatography coupled to a time-of-flight mass spectrometer. Relative abundances of mRNA from different genes related to RXR, ecdysone, and JH signaling pathways were studied by qRT-PCR. Results and Conclusions TBT disrupted the dynamics of neutral lipids, impairing the transfer of triacylglycerols to eggs and hence promoting their accumulation in adult individuals. TBT’s disruptive effects translated into a lower fitness for offspring and adults. Co-regulation of gene transcripts suggests that TBT activates the ecdysone, JH, and RXR receptor signaling pathways, presumably through the already proposed interaction with RXR. These findings indicate the presence of obesogenic effects in a nonvertebrate species. Citation Jordão R, Casas J, Fabrias G, Campos B, Piña B, Lemos MF, Soares AM, Tauler R, Barata C. 2015. Obesogens beyond vertebrates: lipid perturbation by tributyltin in the crustacean Daphnia magna. Environ Health Perspect 123:813–819; http://dx.doi.org/10.1289/ehp.1409163 PMID

  7. Fish bioturbation of cadmium-contaminated sediments: Factors affecting Cd availability to Daphnia magna

    SciTech Connect

    Wall, S.B.; La Point, T.W.; Isely, J.J.

    1996-03-01

    Benthic fish bioturbation of contaminated sediments is thought to enhance exposure and, potentially, bioaccumulation into planktonic organisms. Exposures were conducted with cadmium-spiked sediment, 1.0 mg/kg nominal concentrations, and koi carp (Cyprinus carpio). Daphnia magna were placed in aquaria with and without fish for 6 d and Cd bioaccumulation was measured every 48 h. Koi carp bioturbation increased mean total suspended solids (TSS) in two trials from 0.001 mg/L to 44.4 mg/L and 19.2 mg/L to 762.4 mg/L. Mean aqueous Cd concentrations increased from1.4 {micro}g/L to 2.8 {micro}g/L, and from 1.6 {micro}g/L to 13.2 {micro}g/L. Cadmium binding capacity increased from 28.9 {micro}g/L to 169.8 {micro}g/L in with-fish treatments when compared to controls. However, Daphnia magna body burdens did not increase. Mean Cd residues of daphnids exposed with fish, 9.2 {micro}g/g, were not statistically different from without-fish exposures, 8.0 {micro}g/g. Body burdens slightly decreased in the first trial after the with-fish treatment, 9.4 {micro}g/g to 8.3 {micro}g/g. Fish size was partially correlated with TSS and aqueous Cd concentrations and TSS positively correlated with binding capacity. Because increased TSS in the with-fish treatment resulted in increased binding capacity, it is probable that cadmium bioavailability decreased. Although koi carp were capable of remobilizing Cd from sediment, Cd bioaccumulation into Daphnia magna was not significant.

  8. Acute toxicity of furazolidone on Artemia salina, Daphnia magna, and Culex pipiens molestus larvae

    SciTech Connect

    Macri, A.; Stazi, A.V.; Dojmi di Delupis, G.

    1988-10-01

    As a result of evidence of the ecotoxicity of nitrofurans, the acute toxicity of furazolidone was tested in vivo on two aquatic organisms, Artemia salina and Daphnia magna, which are both crustaceans. Toxicity studies were also performed on larvae of Culex pipiens molestus. Results indicated a significant toxicity of the compound on Culex pipiens and Daphnia magna, while Artemia salina proved to be the least sensitive.

  9. Acute toxicity of cyanogen chloride to Daphnia magna

    SciTech Connect

    Kononen, D.W.

    1988-09-01

    The destruction of cyanide in waste waters by chlorination has been shown to result in the formation of the extremely toxic compound, cyanogen chloride. Industrial cyanide-containing waste waters may be treated by a batch chlorination process under highly alkaline conditions prior to being discharged into a receiving water systems. Alternatively, if the concentration of cyanide is relatively low, and such waste waters may be diverted to municipal waste treatment facilities where they may be subjected to a process of chlorination which may not be sufficient for the complete oxidative destruction of the available cyanide. Although a large body of literature exists concerning the toxicity of HCN and metallic cyanide compounds to aquatic organisms, there is a comparative scarcity of information concerning cyanogen chloride toxicity. This study was designed to determine the acute toxicity of CNCl to Daphnia magna neonates under static bioassay conditions.

  10. Development of miniaturized acute toxicity tests for Daphnia magna and Pimephales promelas

    SciTech Connect

    Powell, R.L.; Kimerle, R.A.; Moser, E.M.; McKee, M.J.

    1995-12-31

    Standard EPA methods for conducting static, 48-hour, acute toxicity tests using Daphnia magna and Pimephales promelas (fathead minnows) can be miniaturized to successfully yield accurate LC50/EC50 values. The screening procedure involves exposing the test organisms to 1 mL of test solution, in test chambers which consist of the wells on 48-well microliter plates. Toxicity of the microliter plates and solvent, DO concentration, organism biomass to test solution ratio, partitioning of the chemicals and dilution of the test solution during transfer of the test organisms were examined. Survival and exposure were not significantly altered using non-standard test chambers. Toxicity of linear alkylbenzene sulfonate (LAS), pentachlorophenol (PCP), kepone, and sodium lauryl sulfate (SLS) was determined using D. magna and fathead minnows. Serial dilutions were made and 1 mL aliquots pipetted into the wells. Daphnia magna, < 24 hours old, and newly hatched fathead minnows, were transferred into the wells, twenty individuals per concentration, one per well. Dose-response curves were established for all test compounds. LC50/EC50`s values obtained using miniaturized methods strongly correlated with those obtained using standard EPA procedures. The tests were repeated a number of times with coefficient of variances for D. magna ranging from 10% with kepone to 64% with SLS. For fathead minnows CVs ranged from 0% with PCP to 23% with kepone. It was concluded that current methods can be miniaturized, yet still provide accurate information regarding toxicity for compounds in limited supply. This method may also be amenable to effluent testing i.e. TIE fractions. Other benefits include reducing the amount of equipment and space needed to conduct a test and the time involved.

  11. Dynamic multipathway modeling of Cd bioaccumulation in Daphnia magna using waterborne and dietborne exposures.

    PubMed

    Goulet, Richard R; Krack, Susannah; Doyle, Patrick J; Hare, Landis; Vigneault, Bernard; McGeer, James C

    2007-02-28

    We tested the predictive ability of the dynamic multipathway bioaccumulation model (DYMBAM) to characterize Cd accumulation in Daphnia magna, a species commonly used in toxicity tests and because of its sensitivity, particularly to metals, a species that is relied upon in ecological risk assessments. We conducted chronic exposure experiments in which D. magna were exposed to either dietborne Cd alone or to both dietborne and waterborne Cd. In the food-only treatments, the algae Chlamydomonas reinhardtii or Pseudokirchneriella subcapitata were pre-exposed to free Cd ion concentrations, [Cd(2+)], from 0.001 to 100nM (0.001-11microgL(-1)) then, on a daily feeding renewal basis, fed to D. magna over 21 days. In the water plus food treatment, D. magna were exposed for 21 days to the same range of [Cd(2+)] and fed with the same algal species that had been exposed to Cd at various concentrations. In the algal exposure media, Cd concentrations in algae were directly related to those in water and were characterized by a linear regression model using the log transformed concentration of the WHAM predicted Cd(2+) concentration. The DYMBAM was used with estimated values of the model constants for ingestion rate (0.08-0.34gg(-1)day(-1)) and growth rate (0.085-0.131day(-1)) based on our experimental data and with literature values for rate constants of Cd influx and efflux as well as Cd assimilation efficiency. Measured Cd concentrations in D. magna agreed with model predictions within a factor of 3. Using the model, we predict that food is an important contributor of Cd burden to D. magna, particularly at lower Cd exposure concentrations over an environmentally realistic gradient of free Cd in water. However, this cladoceran also takes up Cd from water and this exposure route becomes increasingly important at very high concentrations of free Cd (>10nM or 1.1microgL(-1)). Nevertheless, Cd produced lethal effects in D. magna that were exposed to this metal in water and diet, but

  12. Toxicity of new generation flame retardants to Daphnia magna.

    PubMed

    Waaijers, Susanne L; Hartmann, Julia; Soeter, A Marieke; Helmus, Rick; Kools, Stefan A E; de Voogt, Pim; Admiraal, Wim; Parsons, John R; Kraak, Michiel H S

    2013-10-01

    There is a tendency to substitute frequently used, but relatively hazardous brominated flame retardants (BFRs) with halogen-free flame retardants (HFFRs). Consequently, information on the persistence, bioaccumulation and toxicity (PBT) of these HFFRs is urgently needed, but large data gaps and inconsistencies exist. Therefore, in the present study the toxicity of a wide range of HFFRs to the water flea Daphnia magna was investigated. Our results revealed that four HFFRs were showing no effect at their Sw (saturated water concentration) and three had a low toxicity (EC50>10 mg L(-1)), suggesting that these compounds are not hazardous. Antimony trioxide had a moderate toxicity (EC50=3.01 mg L(-1), 95% CL: 2.76-3.25) and triphenyl phosphate and the brominated reference compound tetra bromobisphenol A were highly toxic to D. magna (EC50=0.55 mg L(-1), 95% CL: 0.53-0.55 and EC50=0.60 mg L(-1), 95% CL: 0.24-0.97 respectively). Aluminum trihydroxide and bisphenol A bis(diphenyl phosphate) caused limited mortality at Sw (26 and 25% respectively) and have a low solubility (<10 mg L(-1)). Hence, increased toxicity of these compounds may be observed when for instance decreasing pH could increase solubility. By testing all compounds under identical conditions we provided missing insights in the environmental hazards of new generation flame retardants and propose as best candidates for BFR replacements: APP, ALPI, DOPO, MHO, MPP, ZHS and ZS. PMID:23886749

  13. Acute toxicity of 50 metals to Daphnia magna.

    PubMed

    Okamoto, Akira; Yamamuro, Masumi; Tatarazako, Norihisa

    2015-07-01

    Metals are essential for human life and physiological functions but may sometimes cause disorders. Therefore, we conducted acute toxicity testing of 50 metals in Daphnia magna: EC50s of seven elements (Be, Cu, Ag, Cd, Os, Au and Hg) were < 100 µg l(-1) ; EC50s of 13 elements (Al, Sc, Cr, Co, Ni, Zn, Se, Rb, Y, Rh, Pt, Tl and Pb) were between 100 and 1000 µg l(-1) ; EC50s of 14 elements (Li, V, Mn, Fe, Ge, As, In, Sn, Sb, Te, Cs, Ba, W and Ir) were between 1,001 and 100,000 µg l(-1) ; EC50s of six elements (Na, Mg, K, Ca, Sr and Mo) were > 100,000 µg l(-1) ; and. 7 elements (Ti, Zr, Bi, Nb, Hf, Re and Ta) did not show EC50 at the upper limit of respective aqueous solubility, and EC50s were not obtained. Ga, Ru and Pd adhered to the body of D. magna and physically retarded the movement of D. magna. These metals formed hydroxides after adjusting the pH. Therefore, here, we distinguished this physical effect from the physiological toxic effect. The acute toxicity results of 40 elements obtained in this study were not correlated with electronegativity. Similarly, the acute toxicity results of metals including the rare metals were also not correlated with first ionization energy, atomic weight, atomic number, covalent radius, atomic radius or ionic radius. PMID:25382633

  14. Chronic toxicity of aniline and 2,4-dichlorophenol to Daphnia magna Straus

    SciTech Connect

    Gersich, F.M.; Milazzo, D.P.

    1988-01-01

    Data generated from daphnid chronic toxicity tests are used by various regulatory agencies for the development of water quality criteria. Two chemicals which are lacking reported chronic data are aniline and 2,4-dichlorophenol. The acute toxicity of 2,4-dichlorophenol to Daphnia magna has been reported; the toxicity of aniline to D. magna also has been reported. Chronic data for these chemicals are lacking for invertebrates. The objective of this study was to estimate the chronic toxicity of aniline and 2,4-dichlorophenol to Daphnia magna Straus, using a standard 21-day static renewal procedure.

  15. Population dynamics in Daphnia magna as modified by chronic tetradifon stress.

    PubMed

    Villarroel, M J; Ferrando, M D; Sancho, E; Andreu, E

    2000-03-01

    Two Daphnia magna offsprings (animals from the first and third brood) whose parentals (F0-generation) were exposed during 21 days to different tetradifon (4-chlorophenyl 2,4,5-trichlophenyl sulfone) concentrations, were transferred to a pesticide free medium during 21 days (recovery period). The algae Nannochloris oculata (5 x 10(5) cells/mL) was used as food. In this recovery study, survival, growth and reproduction (mean total young per female, mean brood size, onset of reproduction and mean number broods per female) were assessed as individual parameters and the intrinsic rate of natural increase (r) as population parameter, for F1 generation (1st and 3rd broods). Reproduction was still reduced in F1 (1st and 3rd broods) generation daphnids from parentals (F0) exposed to 0.18 mg/L tetradifon and higher concentrations even after 21 days in clean water. However, survival was not significantly different (p > 0.05) in those F1 offsprings from parentals pre-exposed to the acaricide. Growth was still reduced in F1 daphnids from parentals pre-exposed to 0.10-0.44 mg/L tetradifon. The intrinsic rate of natural increase (r) was still affected in F1 generation daphnids, specially in those from the third brood. Therefore, F1 generation D. magna offsprings from a parental generation (F0) previously exposed to the acaricide tetradifon were not able to recuperate completely when a recovery period of 21 days was allowed. PMID:10736770

  16. Rapid changes in water hardness and alkalinity: Calcite formation is lethal to Daphnia magna.

    PubMed

    Bogart, Sarah J; Woodman, Samuel; Steinkey, Dylan; Meays, Cindy; Pyle, Greg G

    2016-07-15

    There is growing concern that freshwater ecosystems may be negatively affected by ever-increasing anthropogenic inputs of extremely hard, highly alkaline effluent containing large quantities of Ca(2+), Mg(2+), CO3(2-), and HCO3(-) ions. In this study, the toxicity of rapid and extreme shifts in water hardness (38-600mg/L as CaCO3) and alkalinity (30-420mg/L as CaCO3) to Daphnia magna was tested, both independently and in combination. Within these ranges, where no precipitation event occurred, shifts in water hardness and/or alkalinity were not toxic to D. magna. In contrast, 98-100% of D. magna died within 96h after exposure to 600mg/L as CaCO3 water hardness and 420mg/L as CaCO3 alkalinity (LT50 of 60h with a 95% CI of 54.2-66.0h). In this treatment, a CaCO3 (calcite) precipitate formed in the water column which was ingested by and thoroughly coated the D. magna. Calcite collected from a mining impacted stream contained embedded organisms, suggesting field streams may also experience similar conditions and possibly increased mortality as observed in the lab tests. Although further investigation is required to determine the exact fate of aquatic organisms exposed to rapid calcite precipitation in the field, we caution that negative effects may occur more quickly or at lower concentrations of water hardness and alkalinity in which we observed effects in D. magna, because some species, such as aquatic insects, are more sensitive than cladocerans to changes in ionic strength. Our results provide evidence that both calcite precipitation and the major ion balance of waters should be managed in industrially affected ecosystems and we support the development of a hardness+alkalinity guideline for the protection of aquatic life. PMID:27060657

  17. Toxic effect of selenium on the zooplankton, Daphnia magna and Daphnia pulicaria, in water and the food source (Chlamydomonas reinhardtii)

    SciTech Connect

    Boyum, K.W.

    1984-01-01

    Acute and chronic toxicity experiments were performed on the zooplankton, Daphnia magna and Daphnia pulicaria, to investigate the toxicity of selenium on these aquatic invertebrates. The acute 48 h LC/sub 50/ of sodium selenate for Daphnia magna and Daphnia pulicaria were 1.01 and 0.25 mg Se/1, respectively. The 48 h LC/sub 50/ of sodium selenite for D. magna and D. pulicaria were 0.45 and 0.006 mg Se/1, respectively. Chronic 28-day toxicity tests were performed on D. magna at 0.05, 0.10, 0.50, and 1.00 mg Se/1 as sodium selenate in the water and with two food types. One food type was algae raised in clean Lake Michigan water and the second treatment was algae raised in media with selenium concentrations corresponding to those in the water cited above. When compared to Daphnia fed selenium-free algae, D. magna fed selenium-laden algae had greater survival, a greater number of offspring produced, and a greater intrinsic growth rate, r, at the toxicant concentration in the water of 0.05, 0.10, and 0.50 mg Se/1. These parameters were, however, lower than those observed in the controls. Uptake of /sup 75/Se as sodium selenate in D. magna was reduced in the presence of selenium-laden algae and DL-selenomethionine, while L-methionine increased the uptake of /sup 75/Se. Selenium bound to an amino acid such as Dl-selenomethionine or organically bound within an algal food source appears to be preferentially incorporated thereby reducing the uptake of inorganic forms from the water.

  18. Assessment of the effects of the carbamazepine on the endogenous endocrine system of Daphnia magna.

    PubMed

    Oropesa, A L; Floro, A M; Palma, P

    2016-09-01

    In the present study, the endocrine activity of the antiepileptic pharmaceutical carbamazepine (CBZ) in the crustacean Daphnia magna was assessed. To assess the hormonal activity of the drug, we exposed maternal daphnids and embryos to environmental relevant concentrations of CBZ (ranging from 10 to 200 μg/L) and to mixtures of CBZ with fenoxycarb (FEN; 1 μg/L). Chronic exposure to CBZ significantly decreased the reproductive output and the number of molts of D. magna at 200 μg/L. This compound induced the production of male offspring (12 ± 1.7 %), in a non-concentration-dependent manner, acting as a weak juvenile hormone analog. Results showed that this substance, at tested concentrations, did not antagonize the juvenoid action of FEN. Further, CBZ has shown to be toxic to daphnid embryos through maternal exposure interfering with their normal gastrulation and organogenesis stages but not producing direct embryo toxicity. These findings suggest that CBZ could act as an endocrine disruptor in D. magna as it decreases the reproductive output, interferes with sex determination, and causes development abnormality in offspring. Therefore, CBZ could directly affect the population sustainability. PMID:27225007

  19. Effects of naphthalene on the hemoglobin concentration and oxygen uptake of daphnia magna

    SciTech Connect

    Crider, J.Y.; Wilhm, J.; Harman, H.J.

    1982-01-01

    In addition to acute testing for survival of Daphnia magna exposed to naphthalene, various physiological tests were made. Short term studies were conducted to calculate LC50 values and physiological responses. Daphnia of 24 h were fed initially 0.25 ml food/l and the pH, dissolved oxygen and temperature, conductivity, swimming movements, and the number of survivors were determined at 0, 24, and 48 h. These experiments were run at least three times and the dosage-mortality curves were determined by the use of probit and regression analyses. Physiological studies were made for concentrations of 1, 5, and 10 mg/l. Oxygen consumption of Daphnia was measured polarographically and a carboxyhemoglobin method was used to measure total hemoglobin. The hemoglobin concentrations of the treated organisms decreased from 102 nmoles/animal at 1 mg/l naphthalene to 67 nmoles/animal at 9 mg/l. Oxygen uptake decreased from 37 nmoles/animal/h at 1 mg/l to 28 nmoles/animal/h at8 mg/l. Results show that hemoglobin concentration and oxygen uptake may be useful tools in assessing water quality and its effects on the biota. (JMT)

  20. Genes mirror geography in Daphnia magna.

    PubMed

    Fields, Peter D; Reisser, Céline; Dukić, Marinela; Haag, Christoph R; Ebert, Dieter

    2015-09-01

    Identifying the presence and magnitude of population genetic structure remains a major consideration in evolutionary biology as doing so allows one to understand the demographic history of a species as well as make predictions of how the evolutionary process will proceed. Next-generation sequencing methods allow us to reconsider previous ideas and conclusions concerning the distribution of genetic variation, and what this distribution implies about a given species evolutionary history. A previous phylogeographic study of the crustacean Daphnia magna suggested that, despite strong genetic differentiation among populations at a local scale, the species shows only moderate genetic structure across its European range, with a spatially patchy occurrence of individual lineages. We apply RAD sequencing to a sample of D. magna collected across a wide swath of the species' Eurasian range and analyse the data using principle component analysis (PCA) of genetic variation and Procrustes analytical approaches, to quantify spatial genetic structure. We find remarkable consistency between the first two PCA axes and the geographic coordinates of individual sampling points, suggesting that, on a continent-wide scale, genetic differentiation is driven to a large extent by geographic distance. The observed pattern is consistent with unimpeded (i.e. no barriers, landscape or otherwise) migration at large spatial scales, despite the fragmented and patchy nature of favourable habitats at local scales. With high-resolution genetic data similar patterns may be uncovered for other species with wide geographic distributions, allowing an increased understanding of how genetic drift and selection have shaped their evolutionary history. PMID:26190313

  1. Uncovering Cryptic Asexuality in Daphnia magna by RAD Sequencing.

    PubMed

    Svendsen, Nils; Reisser, Celine M O; Dukić, Marinela; Thuillier, Virginie; Ségard, Adeline; Liautard-Haag, Cathy; Fasel, Dominique; Hürlimann, Evelin; Lenormand, Thomas; Galimov, Yan; Haag, Christoph R

    2015-11-01

    The breeding systems of many organisms are cryptic and difficult to investigate with observational data, yet they have profound effects on a species' ecology, evolution, and genome organization. Genomic approaches offer a novel, indirect way to investigate breeding systems, specifically by studying the transmission of genetic information from parents to offspring. Here we exemplify this method through an assessment of self-fertilization vs. automictic parthenogenesis in Daphnia magna. Self-fertilization reduces heterozygosity by 50% compared to the parents, but under automixis, whereby two haploid products from a single meiosis fuse, the expected heterozygosity reduction depends on whether the two meiotic products are separated during meiosis I or II (i.e., central vs. terminal fusion). Reviewing the existing literature and incorporating recombination interference, we derive an interchromosomal and an intrachromosomal prediction of how to distinguish various forms of automixis from self-fertilization using offspring heterozygosity data. We then test these predictions using RAD-sequencing data on presumed automictic diapause offspring of so-called nonmale producing strains and compare them with "self-fertilized" offspring produced by within-clone mating. The results unequivocally show that these offspring were produced by automixis, mostly, but not exclusively, through terminal fusion. However, the results also show that this conclusion was only possible owing to genome-wide heterozygosity data, with phenotypic data as well as data from microsatellite markers yielding inconclusive or even misleading results. Our study thus demonstrates how to use the power of genomic approaches for elucidating breeding systems, and it provides the first demonstration of automictic parthenogenesis in Daphnia. PMID:26341660

  2. Acute and chronic effects of pulse exposure of Daphnia magna to dimethoate and pirimicarb.

    PubMed

    Andersen, Tobias Henrik; Tjørnhøj, Rikke; Wollenberger, Leah; Slothuus, Tina; Baun, Anders

    2006-05-01

    Short-term (<48 h) and long-term (21 d) effects of dimethoate and pirimicarb were studied in Daphnia magna exposed to pulses of 0.5 to 8 h in duration. During a 21-d postexposure observation period, the following parameters were monitored: Mortality, mobility, day for first offspring, animal size, weight of offspring and adults, and number of offspring produced. In general, animals exposed to a single pulse of dimethoate or pirimicarb regained mobility after 24 to 48 h in clean media. Animals exposed to repeated pulses of dimethoate did not recover mobility during a 48-h postexposure observation period, and mortality was significantly increased. Animals exposed to two pulses of pirimicarb showed less recovery of mobility compared with those exposed to one pulse. Exposure of D. magna to 30 mg/L of dimethoate or 100 microg/L of pirimicarb for 2 to 6 h resulted in a significant reduction in the number of offspring and in the average weight of offspring. The average body length was reduced after pulse exposure to 30 mg/L of dimethoate for 3 h or 70 microg/L of pirimicarb for 4 h, and these exposure concentrations caused a delay in the day for first offspring at exposure durations of 2 to 6 h. The most important new findings in the present study are that short-term (<4 h) pulse exposure of neonates to acetylcholinesterase-inhibiting pesticides caused reproductive damage in D. magna and that repeated-pulse exposure significantly increased mortality in animals that apparently had recovered after a single-pulse exposure. PMID:16704047

  3. Daphnia magna negatively affected by chronic exposure to purified Cry-toxins.

    PubMed

    Bøhn, Thomas; Rover, Carina Macagnan; Semenchuk, Philipp Robert

    2016-05-01

    Cry-toxin genes originating from Bacillus thuringiensis are inserted into genetically modified (GM) plants, often called Bt-plants, to provide insect resistance to pests. Significant amounts of Bt-plant residues, and thus Cry-toxins, will be shed to soil and aquatic environments. We exposed Daphnia magna to purified Cry1Ab and Cry2Aa toxins for the full life-span of the animals. We used single toxins in different doses and combinations of toxins and Roundup(®), another potential stressor on the rise in agricultural ecosystems. Animals exposed to 4.5 mg/L (ppm) of Cry1Ab, Cry2Aa and the combination of both showed markedly higher mortality, smaller body size and very low juvenile production compared to controls. Animals exposed to 0.75 mg/L also showed a tendency towards increased mortality but with increased early fecundity compared to the controls. Roundup(®) stimulated animals to strong early reproductive output at the cost of later rapid mortality. We conclude that i) purified Cry-toxins in high concentrations are toxic to D. magna, indicating alternative modes-of-action for these Cry-toxins; ii) Cry-toxins act in combination, indicating that 'stacked events' may have stronger effects on non-target organisms; iii) further studies need to be done on combinatorial effects of multiple Cry-toxins and herbicides that co-occur in the environment. PMID:26993955

  4. Comparative Developmental Staging of Female and Male Water Fleas Daphnia pulex and Daphnia magna During Embryogenesis.

    PubMed

    Toyota, Kenji; Hiruta, Chizue; Ogino, Yukiko; Miyagawa, Shinichi; Okamura, Tetsuro; Onishi, Yuta; Tatarazako, Norihisa; Iguchi, Taisen

    2016-02-01

    The freshwater crustacean genus Daphnia has been used extensively in ecological, developmental and ecotoxicological studies. Daphnids produce only female offspring by parthenogenesis under favorable conditions, but in response to various unfavorable conditions and external stimuli, they produce male offspring. Although we reported that exogenous exposure to juvenile hormones and their analogs can induce male offspring even under female-producing conditions, we recently established a male induction system in the Daphnia pulex WTN6 strain simply by changing day-length. This male and female induction system is suitable for understanding the innate mechanisms of sexual dimorphic development in daphnids. Embryogenesis has been described as a normal plate (developmental staging) in various daphnid species; however, all studies have mainly focused on female development. Here, we describe the developmental staging of both sexes during embryogenesis in two representative daphnids, D. pulex and D. magna, based on microscopic time-course observations. Our findings provide the first detailed insights into male embryogenesis in both species, and contribute to the elucidation of the mechanisms underlying sexual differentiation in daphnids. PMID:26853866

  5. Daphnia magna shows reduced infection upon secondary exposure to a pathogen.

    PubMed

    McTaggart, Seanna J; Wilson, Philip J; Little, Tom J

    2012-12-23

    Previous pathogen exposure is an important predictor of the probability of becoming infected. This is deeply understood for vertebrate hosts, and increasingly so for invertebrate hosts. Here, we test if an initial pathogen exposure changes the infection outcome to a secondary pathogen exposure in the natural host-pathogen system Daphnia magna and Pasteuria ramosa. Hosts were initially exposed to an infective pathogen strain, a non-infective pathogen strain or a control. The same hosts underwent a second exposure, this time to an infective pathogen strain, either immediately after the initial encounter or 48 h later. We observed that an initial encounter with a pathogen always conferred protection against infection compared with controls. PMID:22875818

  6. Bioaccumulation and biomarker responses of cubic and octahedral Cu2O micro/nanocrystals in Daphnia magna.

    PubMed

    Fan, Wenhong; Shi, Zhiwei; Yang, Xiuping; Cui, Minming; Wang, Xiaolong; Zhang, Dongfeng; Liu, Hong; Guo, Lin

    2012-11-15

    Great progress has been made in the controlled fabrication of nanomaterials with given sizes, shapes, and geometries. However, how such changes in structure potentially affect the bioavailability and toxicity of metal nanoparticles to aquatic organisms remains mostly unknown. The present study reports the different behaviors of two types of Cu(2)O micro/nanocrystals (micro/nano-Cu(2)O) with different shapes (cubic and octahedral) and crystallographies (with exposed surfaces as {100} or {111}). The bioaccumulation, median lethal concentration, and biomarker responses of Daphnia magna exposed to the two micro/nanocrystals are also investigated. The Cu accumulation, production of metallothionein (MT), and inhibition ratio of D. magna increased gradually with increasing micro/nano-Cu(2)O concentration. The two crystals showed slight Cu accumulation differences toward D. magna, and their biomarker responses and toxicities to D. magna differed significantly as well. The octahedral Cu(2)O micro/nanocrystals were more toxic to D. magna compared with the cubic micro/nanocrystals probably because of the higher surface activities of the {111} facets compared with those of the {100} facets for cuprites. Food ingestion was the main entry pathway of the micro/nanocrystals into organisms, and toxicity was consequently determined based on the dissolution behavior of the micro/nanocrystals in vivo. PMID:22999974

  7. Chronic effects of cyanobacterial toxins on Daphnia magna and their offspring.

    PubMed

    Dao, Thanh Son; Do-Hong, Lan-Chi; Wiegand, Claudia

    2010-06-15

    The zooplankton grazer Daphnia magna endures living in water bodies up to moderate densities of cyanobacteria, such as Microcystis spp., known for producing toxic secondary metabolites. Although daphnids are affected via decreased food filtering, inhibition of digestive proteases and lethality, development of tolerance against cyanobacterial toxins has also been observed. Aim of our study was to investigate in detail chronic effects of cyanobacterial toxins, with emphasis on microcystin, on D. magna. The animals were exposed chronically for two generations to either microcystin-LR in 5 or 50 microg L(-1), or to cyanobacterial crude extract containing the same amount of total microcystin, starting at neonate stadium. Survival, growth, maturation and fecundity were observed for the first generation during two months. In the offspring survival, maturation, and growth were followed for the first week. Low concentration of microcystin-LR slightly affected the growth and reproduction of parent daphnids. Survivorship decreased during chronic exposure with increasing microcystin concentration. Age to maturity of the offspring increased and their survival decreased after parent generation was exposed to the toxin, even if the offspring were raised in control medium. Besides, cessation of the eggs/embryos was observed and malformation of neonates caused by cyanobacterial toxins was firstly recorded. PMID:20132836

  8. Two-generational effects of contaminants in Daphnia magna: Effects of offspring quality.

    PubMed

    Campos, Bruno; Jordão, Rita; Rivetti, Claudia; Lemos, M F L; Soares, A M V M; Tauler, Roma; Barata, Carlos

    2016-06-01

    The authors set up a protocol to perform a 2-generational ring test using the existing guidelines for the Daphnia magna reproduction test. It is well known in ecology that size and quality of offspring vary across the first clutches in D. magna and that certain chemicals affect offspring quality. Therefore, the origin of the second generation is an important factor to consider. Two-generational effects across first, second, and third clutches were evaluated using 4-nonylphenol; those across first and third clutches were evaluated using tributyltin, and those across the third clutch were evaluated using piperonyl butoxide. The compound showing the greatest aggravation of toxic effects between the parental and second generations was piperonyl butoxide, followed by 4-nonylphenol, whereas intergenerational effects of tributyltin varied across experiments. The studied chemicals affected the quantity and quality of the offspring produced by exposed females of the parental generation, those effects being greater in third-clutch neonates. Therefore, when third-clutch offspring were further exposed, they turned out to be more sensitive than the parental generation. The results are in line with those obtained in multigenerational studies using mammalian tests, which showed that, in many cases, effects on the second generation can be predicted by evaluating the quality of the offspring produced. Environ Toxicol Chem 2016;35:1470-1477. © 2015 SETAC. PMID:26505489

  9. Frequency and inheritance of non-male producing clones in Daphnia magna: evolution towards sex specialization in a cyclical parthenogen?

    PubMed

    Galimov, Y; Walser, B; Haag, C R

    2011-07-01

    In Daphnia (Cladocera, Crustacea), parthenogenetic reproduction alternates with sexual reproduction. Individuals of both sexes that belong to the same parthenogenetic line are genetically identical, and their sex is determined by the environment. Previously, non-male producing (NMP) genotypes have been described in species of the Daphnia pulex group. Such genotypes can only persist through phases of sexual reproduction if they co-occur with normal (MP) genotypes that produce both males and females, and thus the breeding system polymorphism is similar to gynodioecy (coexistence of females with hermaphrodites), which is well known in plants. Here we show that the same breeding system polymorphism also occurs in Daphnia magna, a species that has diverged from D. pulex more than 100 MY ago. Depending on the population, between 0% and 40% of D. magna females do not produce males when experimentally exposed to a concentration of the putative sex hormone methyl farnesoate that normally leads to male-only clutches. Natural broods of these NMP females never contained males, contrasting with high proportions of male offspring in MP females from the same populations. The results from a series of crossing experiments suggest that NMP is determined by a dominant allele at a single nuclear locus (or a several closely linked loci): NMP × MP crosses always yielded 50% NMP and 50% MP offspring, whereas MP × MP crosses always yielded 100% MP offspring. Based on cytochrome c oxidase subunit I-sequences, we found that NMP genotypes from different populations belong to three highly divergent mitochondrial lineages, potentially representing three independent evolutionary origins of NMP in D. magna. Thus, the evolution of NMP genotypes in cyclical parthenogens may be more common than previously thought. Moreover, MP genotypes that coexist with NMP genotypes may have responded to the presence of the latter by partially specializing on male production. Hence, these populations of D

  10. Resistance to a bacterial parasite in the crustacean Daphnia magna shows Mendelian segregation with dominance.

    PubMed

    Luijckx, P; Fienberg, H; Duneau, D; Ebert, D

    2012-05-01

    The influence of host and parasite genetic background on infection outcome is a topic of great interest because of its pertinence to theoretical issues in evolutionary biology. In the present study, we use a classical genetics approach to examine the mode of inheritance of infection outcome in the crustacean Daphnia magna when exposed to the bacterial parasite Pasteuria ramosa. In contrast to previous studies in this system, we use a clone of P. ramosa, not field isolates, which allows for a more definitive interpretation of results. We test parental, F1, F2, backcross and selfed parental clones (total 284 genotypes) for susceptibility against a clone of P. ramosa using two different methods, infection trials and the recently developed attachment test. We find that D. magna clones reliably exhibit either complete resistance or complete susceptibility to P. ramosa clone C1 and that resistance is dominant, and inherited in a pattern consistent with Mendelian segregation of a single-locus with two alleles. The finding of a single host locus controlling susceptibility to P. ramosa suggests that the previously observed genotype-genotype interactions in this system have a simple genetic basis. This has important implications for the outcome of host-parasite co-evolution. Our results add to the growing body of evidence that resistance to parasites in invertebrates is mostly coded by one or few loci with dominance. PMID:22167056

  11. Postexposure feeding depression: a new toxicity endpoint for use in laboratory studies with Daphnia magna.

    PubMed

    McWilliam, Ruth A; Baird, Donald J

    2002-06-01

    In situ bioassays with daphnids currently employ lethality as an endpoint, and although sublethal responses (reproduction and feeding rate) can be measured in the field, such endpoints pose major practical challenges. Previous studies have indicated that Daphnia magna exposed to toxic substances can exhibit delayed recovery in feeding behavior (postexposure feeding depression). This simple, robust response has the potential to be an ecologically relevant and potentially diagnostic endpoint. This study developed and tested the use of postexposure feeding depression as a toxicity endpoint in the laboratory environment. First, replicate numbers were manipulated to produce statistically reliable results. Second, postexposure feeding depression in D. magna was studied under laboratory conditions, by employing toxic substances with differing modes of action. Although most substances caused feeding inhibition during direct exposure, not all substances produced postexposure feeding depression. However, the use of lethality as a supplementary endpoint provided an alternative measure when no feeding depression was apparent after exposure. In combination, these endpoints offer a potentially more sensitive, ecologically relevant alternative to the use of lethality alone for in situ bioassay studies. PMID:12069303

  12. Changes of chemical chronic toxicity to Daphnia magna under different food regimes.

    PubMed

    Pavlaki, Maria D; Ferreira, Abel L G; Soares, Amadeu M V M; Loureiro, Susana

    2014-11-01

    In aquatic ecosystems several stressors may act together and affect the life traits of organisms. Pesticide runoffs are usually associated with high inputs of organic matter and depletion of oxygen in aquatic systems. This study aimed at combining anthropogenic stress (chemicals) and natural stress (food availability) and evaluates their joint effect to the life traits of Daphnia magna. The neonicotinoid insecticide imidacloprid and the heavy metal nickel chloride were used and a 21 d chronic test was carried out to obtain reproduction and growth data. The conceptual model Independent action, usually used for assessing response patterns in chemical mixtures, was used for data interpretation. Results showed an increase in the reproduction and growth pattern of D. magna as food levels increased. Both chemicals significantly impaired the reproduction as well as the somatic growth of the organism while the same happened with food concentrations lower than 3×10(5) cells/mL. It was also observed that food availability did not change the toxicity of imidacloprid and nickel chloride when food levels were higher than 3×10(5) cells/mL. When combined with low food levels, imidacloprid showed a slight increase in toxicity, showing that daphnids become more sensitive with reduced food availability, however in a non-significant way. However, toxicity of nickel appeared to be independent of the food level. Both chemicals induced mortality to the organisms exposed in the absence of food only at the end of the test. PMID:25164202

  13. Salinity tolerance of Daphnia magna and potential use for estuarine sediment toxicity tests.

    PubMed

    Schuytema, G S; Nebeker, A V; Stutzman, T W

    1997-08-01

    Daphnia magna Straus, a common organism used for freshwater sediment toxicity tests, was evaluated to determine its tolerance to salinity and suitability for tests with estuarine water and sediments. Daphnids were exposed for 2 to 21 days to salinity in a variety of water-only tests, in tests with freshwater sediment overlain by salt water, and in tests with estuarine sediments overlain by freshwater. Daphnid age, test length, and temperature seemed to have little effect upon the range of LC50, NOAEL, and LOAEL values. LC50s for all tests ranged from 5.10 to 7.81 g/L, with a mean of 6.6 g/L salinity (measured conductivity 10.0 mS/cm) [corrected]. The mean NOAEL and LOAEL values based on production of young were 4.6 and 6.9 g/L salinity (measured conductivity 7.1 and 10.5 mS/cm) [corrected], respectively. The results indicate that D. magna will survive and reproduce well in water with salinities below 4 g/L and demonstrate the potential usefulness of this organism in monitoring sediment toxicity from both freshwater and estuarine wetland sites. PMID:9294248

  14. Global cytosine methylation in Daphnia magna depends on genotype, environment, and their interaction.

    PubMed

    Asselman, Jana; De Coninck, Dieter I M; Vandegehuchte, Michiel B; Jansen, Mieke; Decaestecker, Ellen; De Meester, Luc; Vanden Bussche, Julie; Vanhaecke, Lynn; Janssen, Colin R; De Schamphelaere, Karel A C

    2015-05-01

    The authors characterized global cytosine methylation levels in 2 different genotypes of the ecotoxicological model organism Daphnia magna after exposure to a wide array of biotic and abiotic environmental stressors. The present study aimed to improve the authors' understanding of the role of cytosine methylation in the organism's response to environmental conditions. The authors observed a significant genotype effect, an environment effect, and a genotype × environment effect. In particular, global cytosine methylation levels were significantly altered after exposure to Triops predation cues, Microcystis, and sodium chloride compared with control conditions. Significant differences between the 2 genotypes were observed when animals were exposed to Triops predation cues, Microcystis, Cryptomonas, and sodium chloride. Despite the low global methylation rate under control conditions (0.49-0.52%), global cytosine methylation levels upon exposure to Triops demonstrated a 5-fold difference between the genotypes (0.21% vs 1.02%). No effects were found in response to arsenic, cadmium, fish, lead, pH of 5.5, pH of 8, temperature, hypoxia, and white fat cell disease. The authors' results point to the potential role of epigenetic effects under changing environmental conditions such as predation (i.e., Triops), diet (i.e., Cryptomonas and Microcystis), and salinity. The results of the present study indicate that, despite global cytosine methylation levels being low, epigenetic effects may be important in environmental studies on Daphnia. PMID:25639773

  15. Depressing Antidepressant: Fluoxetine Affects Serotonin Neurons Causing Adverse Reproductive Responses in Daphnia magna.

    PubMed

    Campos, Bruno; Rivetti, Claudia; Kress, Timm; Barata, Carlos; Dircksen, Heinrich

    2016-06-01

    Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants. As endocrine disruptive contaminants in the environment, SSRIs affect reproduction in aquatic organisms. In the water flea Daphnia magna, SSRIs increase offspring production in a food ration-dependent manner. At limiting food conditions, females exposed to SSRIs produce more but smaller offspring, which is a maladaptive life-history strategy. We asked whether increased serotonin levels in newly identified serotonin-neurons in the Daphnia brain mediate these effects. We provide strong evidence that exogenous SSRI fluoxetine selectively increases serotonin-immunoreactivity in identified brain neurons under limiting food conditions thereby leading to maladaptive offspring production. Fluoxetine increases serotonin-immunoreactivity at low food conditions to similar maximal levels as observed under high food conditions and concomitantly enhances offspring production. Sublethal amounts of the neurotoxin 5,7-dihydroxytryptamine known to specifically ablate serotonin-neurons markedly decrease serotonin-immunoreactivity and offspring production, strongly supporting the effect to be serotonin-specific by reversing the reproductive phenotype attained under fluoxetine. Thus, SSRIs impair serotonin-regulation of reproductive investment in a planktonic key organism causing inappropriately increased reproduction with potentially severe ecological impact. PMID:27128505

  16. Developing antibodies from cholinesterase derived from prokaryotic expression and testing their feasibility for detecting immunogen content in Daphnia magna *

    PubMed Central

    Liu, Hong-cui; Yuan, Bing-qiang; Li, Shao-nan

    2016-01-01

    To yield cholinesterase (ChE) from prokaryotic expression, the ChE gene that belongs to Daphnia magna was amplified by reverse transcription-polymerase chain reaction (RT-PCR) using forward primer 5'-CCCYGGNGCSAT GATGTG-3' and reverse primer 5'-GYAAGTTRGCCCAATATCT-3'. To express the gene, one sequence of the amplified DNA, which was able to encode a putative protein containing two conserved carboxylesterase domains, was connected to the prokaryotic expression vector PET-29a(+). The recombinant vector was transformed into Escherichia coil BL21 (DE3). Protein expression was induced by isopropy-D-thiogalactoside. The expressed ChE was used as an immunogen to immunize BALB/c mice. The obtained antibodies were tested for their specificity towards crude enzymes from species such as Alona milleri, Macrobrachium nipponense, Bombyx mori, Chironomus kiiensis, Apis mellifera, Eisenia foetida, Brachydanio rerio, and Xenopus laevis. Results indicated that the antibodies had specificity suitable for detecting ChE in Daphnia magna. A type of indirect and non-competitive enzyme-linked immunosorbent assay (IN-ELISA) was used to test the immunoreactive content of ChE (ChE-IR) in Daphina magna. The detection limit of the IN-ELISA was found to be 14.5 ng/ml at an antiserum dilution of 1:22 000. Results from tests on Daphnia magna exposed to sublethal concentrations of triazophos indicated a maximal induction of 57.2% in terms of ChE-IR on the second day after the animals were exposed to a concentration of 2.10 μg/L triazophos. Testing on animals acclimatized to a temperature of 16 °C indicated that ChE-IR was induced by 16.9% compared with the ChE-IR content detected at 21 °C, and the rate of induction was 25.6% at 10 °C. The IN-ELISA was also used to test the stability of ChE-IR in collected samples. Repeated freezing and thawing had no influence on the outcome of the test. All these results suggest that the polyclonal antibodies developed against the recombinant ChE are as

  17. Developing antibodies from cholinesterase derived from prokaryotic expression and testing their feasibility for detecting immunogen content in Daphnia magna.

    PubMed

    Liu, Hong-cui; Yuan, Bing-qiang; Li, Shao-nan

    2016-02-01

    To yield cholinesterase (ChE) from prokaryotic expression, the ChE gene that belongs to Daphnia magna was amplified by reverse transcription-polymerase chain reaction (RT-PCR) using forward primer 5'-CCCYGGNGCSAT GATGTG-3' and reverse primer 5'-GYAAGTTRGCCCAATATCT-3'. To express the gene, one sequence of the amplified DNA, which was able to encode a putative protein containing two conserved carboxylesterase domains, was connected to the prokaryotic expression vector PET-29a(+). The recombinant vector was transformed into Escherichia coil BL21 (DE3). Protein expression was induced by isopropy-D-thiogalactoside. The expressed ChE was used as an immunogen to immunize BALB/c mice. The obtained antibodies were tested for their specificity towards crude enzymes from species such as Alona milleri, Macrobrachium nipponense, Bombyx mori, Chironomus kiiensis, Apis mellifera, Eisenia foetida, Brachydanio rerio, and Xenopus laevis. Results indicated that the antibodies had specificity suitable for detecting ChE in Daphnia magna. A type of indirect and non-competitive enzyme-linked immunosorbent assay (IN-ELISA) was used to test the immunoreactive content of ChE (ChE-IR) in Daphina magna. The detection limit of the IN-ELISA was found to be 14.5 ng/ml at an antiserum dilution of 1:22 000. Results from tests on Daphnia magna exposed to sublethal concentrations of triazophos indicated a maximal induction of 57.2% in terms of ChE-IR on the second day after the animals were exposed to a concentration of 2.10 μg/L triazophos. Testing on animals acclimatized to a temperature of 16 °C indicated that ChE-IR was induced by 16.9% compared with the ChE-IR content detected at 21 °C, and the rate of induction was 25.6% at 10 °C. The IN-ELISA was also used to test the stability of ChE-IR in collected samples. Repeated freezing and thawing had no influence on the outcome of the test. All these results suggest that the polyclonal antibodies developed against the recombinant ChE are as

  18. Behavioral response of Daphnia magna to silver salt and nanoparticle exposure

    EPA Science Inventory

    Endpoints in the investigation of the toxicity of metallic nanoparticles have varied from genetic and molecular through whole organism responses such as death and reproduction. The work presented here is an effort to quantify behavioral responses of Daphnia magna to exposure to s...

  19. Development and validation of a Daphnia magna four-day survival and growth test method

    EPA Science Inventory

    Zooplankton are an important part of the aquatic ecology of all lakes and streams. As a result, numerous methods have been developed to assess the quality of waterbodies using various zooplankton species. Included in these is the freshwater species Daphnia magna. Current test me...

  20. EFFECTIVE CONCENTRATIONS OF 6 CONTAMINANTS TO LEMMA MINOR, PIMEPHALES PROMELA, DAPHNIA MAGNA, AND CERIODAPHNIA DUBIA

    EPA Science Inventory

    The research presented here resulted in EC50 and LOEC values for the contaminants copper, cadmium, diazinon, atrazine, and cyanide to the species Lemna Minor, Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia. Observed values were used as benchmarks for assessing the se...

  1. EFFECTS OF INORGANIC COMPLEXING ON THE TOXICITY OF COPPER TO 'DAPHNIA MAGNA'

    EPA Science Inventory

    The report includes the effects of carbonate-bicarbonate, orthophosphate, and pyrophosphate on the toxicity of copper (II) to Daphnia magna studied at constant pH and total hardness. Mortality rates and reciprocal survival times were directly correlated with cupric (Cu2+) and cop...

  2. Multigenerational acclimation of Daphnia magna to mercury: relationships between biokinetics and toxicity.

    PubMed

    Tsui, Martin T K; Wang, Wen-Xiong

    2005-11-01

    We examined the effects of multigenerational exposure of mercury (Hg) on Hg toxicity and biokinetics in a population of Daphnia magna. After chronic Hg exposure at 3.8 microg Hg/L, the first generation (F0) adults had an elevated 24-h median lethal concentration (LC50) of Hg (76 microg/L) when compared to the control adults (56 microg/L). The dissolved influx rate of Hg was depressed significantly in the Hg-treated adults, which was accompanied by a reduced ingestion rate and enhanced induction of metallothionein-like proteins (MTLP). The second-generation (F1) juveniles originating from the control and exposed lines had no major differences in these parameters (except the dietary assimilation efficiency). Recovery from Hg stress enhanced the vulnerability of F1 adults to Hg toxicity, with a reduced 48-h LC50 (44 microg/L) and a decreased concentration of MTLP (80% of control). Nevertheless, Hg-treated F1 adults had similar tolerance (in terms of LC50s) as the control line, indicating that D. magna acclimated to Hg stress after the first generation of exposure. No major difference occurred in the Hg biokinetics and toxicity among different groups of F2 daphnids. However, the F2 neonates produced by the Hg-treated F1 adults had much higher 48-h LC50 (149 microg/L) and MTLP concentration (148% of control) when there was continuous Hg exposure after birth. We concluded that acclimation to Hg stress occurred quickly in D. magna, though animals recovering from Hg stress were more vulnerable to Hg toxicity. Both ingestion rate and MTLP may not be good biomarkers of Hg stress in the field, because acclimation can be achieved through multigenerational exposure to elevated Hg concentrations. PMID:16398130

  3. Deciphering mechanisms of malathion toxicity under pulse exposure of the freshwater cladoceran Daphnia magna.

    PubMed

    Trac, Lam Ngoc; Andersen, Ole; Palmqvist, Annemette

    2016-02-01

    The organophosphate pesticide (OP) malathion is highly toxic to freshwater invertebrates, including the cladoceran Daphnia magna, a widely used test organism in ecotoxicology. To assess whether toxic effects of malathion are driven primarily by exposure concentration or exposure duration, D. magna was pulse exposed to equivalent integrated doses (duration × concentration): 3 h × 16 μg/L, 24 h × 2 μg/L, and 48 h × 1 μg/L. After recovery periods of 3 h, 24 h, and 48 h, the toxicity of malathion on different biological levels in D. magna was examined by analyzing the following endpoints: survival and immobilization; enzyme activities of acetylcholinesterase (AChE), carboxylesterase (CbE), and glutathione S-transferase (GST); and AChE gene expression. The results showed no difference in survival among equivalent integrated doses. Adverse sublethal effects were driven by exposure concentration rather than pulse duration. Specifically, short pulse exposure to a high concentration of malathion resulted in more immobilized daphnids, lower AChE and CbE activities, and a higher transcript level of AChE gene compared with long pulse exposure to low concentration. The expression of the AChE gene was up-regulated, indicating a compensatory mechanism to cope with enzyme inhibition. The study shows the need for obtaining a better understanding of the processes underlying toxicity under realistic exposure scenarios, so this can be taken into account in environmental risk assessment of pesticides. PMID:26419489

  4. Linear solvation energy relationships for toxicity of selected organic chemicals to Daphnia pulex and Daphnia magna

    USGS Publications Warehouse

    Passino, Dora R.M.; Hickey, James P.; Frank, Anthony M.

    1988-01-01

    In the Laurentian Great Lakes, more than 300 contaminants have been identified in fish, other biota, water, and sediment. Current hazard assessment of these chemicals by the National Fisheries Research Center-Great Lakes is based on their toxicity, occurrence in the environment, and source. Although scientists at the Center have tested over 70 chemicals with the crustacean Daphnia pulex, the number of experimental data needed to screen the huge array of chemicals in the Great Lakes exceeds the practical capabilities of conducting bioassays. This limitation can be partly circumvented, however, by using mathematical models based on quantitative structure-activity relationships (QSAR) to provide rapid, inexpensive estimates of toxicity. Many properties of chemicals, including toxicity, bioaccumulation and water solubility are well correlated and can be predicted by equations of the generalized linear solvation energy relationships (LSER). The equation we used to model solute toxicity is Toxicity = constant + mVI/100 + s (π* + dδ) + bβm + aαm where VI = intrinsic (Van der Waals) molar volume; π* = molecular dipolarity/polarizability; δ = polarizability 'correction term'; βm = solute hydrogen bond acceptor basicity; and αm = solute hydrogen bond donor acidity. The subscript m designates solute monomer values for α and β. We applied the LSER model to 48-h acute toxicity data (measured as immobilization) for six classes of chemicals detected in Great Lakes fish. The following regression was obtained for Daphnia pulex (concentration = μM): log EC50 = 4.86 - 4.35 VI/100; N = 38, r2 = 0.867, sd = 0.403 We also used the LSER modeling approach to analyze to a large published data set of 24-h acute toxicity for Daphnia magna; the following regression resulted, for eight classes of compounds (concentration = mM): log EC50 = 3.88 - 4.52 VI/100 - 1.62 π* + 1.66 βm - 0.916 αm; N = 62, r2 = 0.859, sd = 0.375 In addition we developed computer software that identifies

  5. Composition and stability of the microbial community inside the digestive tract of the aquatic crustacean Daphnia magna.

    PubMed

    Freese, Heike M; Schink, Bernhard

    2011-11-01

    Small filter-feeding zooplankton organisms like the cladoceran Daphnia spp. are key members of freshwater food webs. Although several interactions between Daphnia and bacteria have been investigated, the importance of the microbial communities inside Daphnia guts has been studied only poorly so far. In the present study, we characterised the bacterial community composition inside the digestive tract of a laboratory-reared clonal culture of Daphnia magna using 16S rRNA gene libraries and terminal-restriction length polymorphism fingerprint analyses. In addition, the diversity and stability of the intestinal microbial community were investigated over time, with different food sources as well as under starvation stress and death, and were compared to the community in the cultivation water. The diversity of the Daphnia gut microbiota was low. The bacterial community consisted mainly of Betaproteobacteria (e.g. Limnohabitans sp.), few Gammaproteobacteria (e.g. Pseudomonas sp.) and Bacteroidetes that were related to facultatively anaerobic bacteria, but did not contain typical fermentative or obligately anaerobic gut bacteria. Rather, the microbiota was constantly dominated by Limnohabitans sp. which belongs to the Lhab-A1 tribe (previously called R-BT065 cluster) that is abundant in various freshwaters. Other bacterial groups varied distinctly even under constant cultivation conditions. Overall, the intestinal microbial community did not reflect the community in the surrounding cultivation water and clustered separately when analysed via the Additive Main Effects and Multiplicative Interaction model. In addition, the microbiota proved to be stable also when Daphnia were exposed to bacteria associated with a different food alga. After starvation, the community in the digestive tract was reduced to stable members. After death of the host animals, the community composition in the gut changed distinctly, and formerly undetected bacteria were activated. Our results suggest

  6. Trans generational effects of the neurotoxin BMAA on the aquatic grazer Daphnia magna.

    PubMed

    Faassen, Elisabeth J; García-Altares, María; Mendes e Mello, Mariana; Lürling, Miquel

    2015-11-01

    β-N-Methylamino-l-alanine (BMAA) is a neurotoxin that is suspected to play a role in the neurological diseases amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease. BMAA has been detected in phytoplankton and globally, the main exposure routes for humans to BMAA are through direct contact with phytoplankton-infested waters and consumption of BMAA-contaminated fish and invertebrates. As BMAA can be transferred from mothers to offspring in mammals, BMAA exposure is expected to have transgenerational effects. The aim of our study was to determine whether maternal exposure to BMAA affects offspring fitness in zooplankton. We performed a multigenerational life history experiment and a multigenerational uptake experiment with the water flea Daphnia magna as a model species. In both experiments, offspring from nonexposed and exposed mothers were raised in clean and BMAA-containing medium. Direct exposure to 110μg/l BMAA reduced survival, somatic growth, reproduction and population growth. Maternal exposure did not affect D. magna fitness: animals from exposed mothers that were raised in clean medium had a higher mortality and produced lighter neonates than the controls, but this did not result in lower population growth rates. No evidence of adaptation was found. Instead, multigeneration exposure to BMAA had a negative effect: animals that were exposed during two generations had a lower brood viability and neonate weight than animals born from unexposed mothers, but raised in BMAA-containing medium. Maternal transfer of BMAA was observed, but BMAA concentrations in neonates raised in BMAA containing medium were similar for animals born from exposed and unexposed mothers. Our results indicate that zooplankton might be an important vector for the transfer of BMAA along the pelagic food chain, but whether BMAA plays a role in preventing zooplankton from controlling cyanobacterial blooms needs further investigation. PMID:26465128

  7. Effects of multigenerational exposure to elevated temperature on reproduction, oxidative stress, and Cu toxicity in Daphnia magna.

    PubMed

    Bae, Eunhye; Samanta, Palas; Yoo, Jisu; Jung, Jinho

    2016-10-01

    This study evaluated the effect of temperature (20 and 25°C) on reproduction, oxidative stress, and copper (Cu) toxicity in Daphnia magna across three generations (F0, F1, and F2). Exposing D. magna to elevated temperature significantly decreased the number of offspring per female per day, the time to first brood, and body length compared to exposure to the optimal temperature (p<0.05). In addition, elevated temperature induced a significantly higher production of reactive oxygen species and lipid peroxidation (p<0.05). These findings suggest that D. magna likely responded to thermal stress by investing more energy into defense mechanisms, rather than growth and reproduction. In addition, oxidative stress at the elevated temperature gradually increased with each generation, possibly owing to the reduced fitness of the offspring. Exposing D. magna to 25°C (EC50=34±3µgL(-1)) substantially increased the median effective concentration of Cu in all generations compared to exposure to 20°C (EC50=25±3µgL(-1)), indicating a decrease in acute toxicity at elevated temperature. However, elevated temperature significantly increased the oxidative stress induced by a sublethal concentration of Cu (10µgL(-1)). The interaction between elevated temperature and Cu exposure appears to be synergistic; however, this needs to be confirmed using multiple generations in a long-term experiment. PMID:27376351

  8. The induction of metallothioneins during pulsed cadmium exposure to Daphnia magna: Recovery and trans-generational effect.

    PubMed

    Li, Shuang; Sheng, Lianxi; Xu, Jingbo; Tong, Haibin; Jiang, Haibo

    2016-04-01

    Although the importance of pulse exposure has gained ground in recent years, there were few studies on recovery and trans-generational effect of it. Two successive generations Daphnia magna were exposed to cadmium (Cd) pulses for 6h at the concentrations from 40 to 100 µg/l. The changes of tolerance and induction of MTs in exposed D. magna and their offspring were measured. The reduced tolerance of exposed D. magna was returned to levels similar to control after about 9 days in a generation. The level of MT still increased up to 3 days after exposure. In the experimental range, exposure duration played a decisive role in MT induction. The tolerance of F1 was lower than F0 and decreased with increasing pulsed concentrations of F0. Exposed to the same pulse, the MT levels of F1 were higher than the MT levels of F0, but the more obvious detoxification of MT in F1 had not been found. Our results suggest that pulsed cadmium exposure had impact on offspring of exposed organism and the risk assessment should take trans-generational effect into account. PMID:26720811

  9. Correlation between heavy metal acute toxicity values in Daphnia magna and fish

    SciTech Connect

    Khangarot, B.S.; Ray, P.K.

    1987-04-01

    In the toxicant bioassays, invertebrates with special reference to aquatic arthropod species have been of recent interest as test models due to the need for developing nonmammalian tests system. The cladoceran Daphnia magna bioassays have several practical advantages. D. magna has been used as a useful test species and its sensitivity to environmental pollutants have been recognized as a general representative of other freshwater zooplankton species. The objectives of this study were to determine the acute toxicity of various heavy metals to Daphnia magna for 48 h of exposure and to compare these values with the existing LC50 values for rainbow trout (Salmo gairdneri); which is commonly used as a test animal in aquatic bioassay studies.

  10. Effects of copper pre-exposure routes on the energy reserves and subsequent copper toxicity in Daphnia magna.

    PubMed

    Canli, M

    2006-10-01

    The hypothesis was tested that copper uptake routes affect the tolerance of Daphnia magna to copper and influence the energy reserves. These were determined in D. magna juveniles that had been exposed for 4 days to water borne and/or dietary copper (algae Pseudokichneriella subcapitata loaded with copper) at nominal concentrations of 0, 10, and 100 nM. Tolerance increased with dietary copper pre-exposure reflected in 24 and 48 h LC50 values of 466 and 398 nM at 100 nM pre-exposure versus 301 and 254 nM in controls, respectively. Control animals (no copper added to their exposure medium and diet) had the lowest lipid content and consequently the lowest energy content. The current study stresses the importance of addressing dietary exposure routes in metal toxicity assessments. PMID:16944514

  11. Ecotoxicity of contaminated suspended solids for filter feeders (Daphnia magna).

    PubMed

    Weltens, R; Goossens, R; Van Puymbroeck, S

    2000-10-01

    It is generally assumed that the dissolved fraction of a toxic substance in surface water is mainly responsible for toxicity to aquatic organisms. However, toxic compounds are often adsorbed or chemically bound to suspended particles in the water column, depending upon the physico-chemical conditions. In the present study potential adverse effects to filter feeding organisms by metal contaminated particles were investigated. In our hypotheses the adsorbed metals might desorb in the gastrointestinal tract-due to different physico-chemical conditions-and exert toxic effects. Clay and sand particles, algae and organic material (peat) were artificially contaminated with cadmium and zinc. The contaminated materials were resuspended in standard conditions and toxicity was measured for the water flea Daphnia magna (mortality at 48 hours). As a reference, supernatant solutions were used containing the same concentration of dissolved metal as the suspensions. It was also established that the test concentrations of solid material (250 and 500 mg/l uncontaminated particles) did not cause any mortality within 48 hours. Daphnids are filter feeders: they filtrate large amounts of surrounding water, redrawing particles as a food source. Results strongly indicate that contaminated particles threaten the health of these particle-feeding organisms. Compared to the reference severe acute toxic effects were seen and cadmium accumulation was increased when contaminated solid material was present. Results were essentially the same for the different materials used in the experiments, except for sand contaminated with cadmium. This shows that mineral as well as organic materials can contribute to the particle bound toxicity. Different results were obtained when a static set up was used instead of a flow through set up, illustrating that the route of administration is important to make particles available and thus to evaluate their toxicity. Contaminated particles clearly have toxic

  12. The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna.

    PubMed

    Sarapultseva, Elena I; Dubrova, Yuri E

    2016-10-01

    The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000mGy of acute γ-rays. Exposure to 1000 and 10,000mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F0 and F1Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F0Daphnia exposed to 1000 and 10,000mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F2 total fertility was compromised only among progeny of parents that received the highest dose of 10,000mGy. We propose that the decreased fertility observed among the F2 progeny of parents exposed to 10,000mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F2 progeny of irradiated F0Daphnia exposed to the lower doses of acute γ-rays. PMID:27288911

  13. Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

    USGS Publications Warehouse

    Meinertz, J.R.; Greseth, Shari L.; Gaikowski, M.P.; Schmidt, L.J.

    2008-01-01

    A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid?? is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid?? on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid??. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0??mg L- 1. The study was initiated with < 24-h-old Daphnia (1 daphnid per chamber) that were exposed to hydrogen peroxide for 21??days. Hydrogen peroxide concentrations ??? 1.25??mg L- 1 had no significant effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations ??? 0.63??mg L- 1 had no significant effect on the total number of young produced. Concentrations ??? 0.32??mg L- 1 had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at ??? 0.63??mg L- 1 for less than 21??days.

  14. Transgenerational effects of two antidepressants (sertraline and venlafaxine) on Daphnia magna life history traits.

    PubMed

    Minguez, Laëtitia; Ballandonne, Céline; Rakotomalala, Christiane; Dubreule, Christelle; Kientz-Bouchart, Valérie; Halm-Lemeille, Marie-Pierre

    2015-01-20

    The low levels of antidepressants detected in surface waters currently raise concern about their potential long-term risks to nontarget aquatic organisms. We investigated the transgenerational effects of sertraline, a selective serotonin reuptake inhibitor, and venlafaxine, a serotonin-norepinephrine reuptake inhibitor, on the life traits of Daphnia magna over two generations under environmentally realistic concentrations. We also studied the reversibility of the effect using recovery experiments. We assessed daphnid survival, growth, and reproduction over 21 days and evidenced detectable effects of the antidepressants. Sertraline increased the F0-daphnid fecundity whereas it decreased the offspring number of F1-daphnids. Transfer to clean medium caused negative effects on the offspring of daphnids exposed to 0.3 μg L(–1), but improved the fecundity of offspring of daphnids exposed to 100 μg L(–1). Venlafaxine exposure decreased the offspring number of F0-daphnids and resulted in drug tolerance in the F1 generation. Sertraline, unlike venlafaxine, may turn out to be a true environmental threat due to its accumulation in algae and the physiological weakness observed over generations. These effects across generations point out to the need to perform multigeneration tests to assess the environmental risk of pharmaceuticals in nontarget organisms. PMID:25506746

  15. Physiological and biochemical perturbations in Daphnia magna following exposure to the model environmental estrogen diethylstilbestrol

    SciTech Connect

    Baldwin, W.S.; Milam, D.L.; LeBlanc, G.A.

    1995-06-01

    The estrogenic properties of many environmental contaminants, such as DDE and PCBs, have been associated with reproductive failure in a variety of vertebrate species. While estrogens have been measured in many invertebrate species, the function of this hormone in invertebrates is controversial. The objective of the present study was to identify possible physiological and biochemical target sites for the estrogenic effects of some xenobiotics on the freshwater crustacean Daphnia magna using the model environmental estrogen diethylstilbestrol (DES). Chronic exposure of daphnids to 0.50 mg/L DES reduced molting frequency among first-generation juveniles and decreased fecundity of second-generation daphnids. Adult first-generation daphnids chronically exposed to DES, as well as adult daphnids acutely exposed to DES for only 48 h, were examined for steroid hormone metabolic capabilities using testosterone as the model steroid. The rate of elimination of two major hydroxylated metabolites of testosterone was significantly reduced, and elimination of glucose conjugates of testosterone was significantly elevated from exposure to 0.50 mg/L DES. These results demonstrate that multigeneration exposure of daphnids to DES results in reduced fecundity and altered steroid metabolic capabilities. Thus, some arthropods, like vertebrates, are sensitive to the effects of endocrine-disrupting chemicals.

  16. Small RNA Sequencing Based Identification of MiRNAs in Daphnia magna

    PubMed Central

    2015-01-01

    Small RNA molecules are short, non-coding RNAs identified for their crucial role in post-transcriptional regulation. A well-studied example includes miRNAs (microRNAs) which have been identified in several model organisms including the freshwater flea and planktonic crustacean Daphnia. A model for epigenetic-based studies with an available genome database, the identification of miRNAs and their potential role in regulating Daphnia gene expression has only recently garnered interest. Computational-based work using Daphnia pulex, has indicated the existence of 45 miRNAs, 14 of which have been experimentally verified. To extend this study, we took a sequencing approach towards identifying miRNAs present in a small RNA library isolated from Daphnia magna. Using Perl codes designed for comparative genomic analysis, 815,699 reads were obtained from 4 million raw reads and run against a database file of known miRNA sequences. Using this approach, we have identified 205 putative mature miRNA sequences belonging to 188 distinct miRNA families. Data from this study provides critical information necessary to begin an investigation into a role for these transcripts in the epigenetic regulation of Daphnia magna. PMID:26367422

  17. Free ionic nickel accumulation and localization in the freshwater zooplankter, Daphnia magna

    SciTech Connect

    Hall, T.M.

    1982-01-01

    The processes which lead to the accumulation of free ionic nickel (radioactive) from solution by Daphnia magna were studied and incorporated into a model which describes accummulation at different concentrations. Adsorption proved to be a relatively small component of nickel accummulation. The accummulation rate eventually approached zero, which represented an equilibrium between uptake and loss of nickel. However, elimination experiments did reveal a pool of relatively static nickel. The appearance and distribution of nickel within five body parts (body fluid, carapace, gut, filtering appendages, and eggs) of D. magna supported the accummulation data and added to the understanding of the pathways of nickel through the organism.

  18. Reproducibility of a life-cycle toxicity test with Daphnia magna

    SciTech Connect

    Parkhurst, B.R.; Forte, J.L.; Wright, G.P.

    1981-01-01

    Standardized chronic life-cycle toxicity testing procedures for aquatic species are described. The reproducibility of chronic toxicity and points using the static-renewal method with Daphnia magna are investigated. The objectives were to determine if the lowest rejected concentrations tested (LRCTs) obtained for six different toxicity criteria in static-renewal tests with acridine were reproducible over time and to determine the relative sensitivity and variability of the toxicity criteria. Two of the six toxicity criteria, numbers of young per brood and the young produced per female, were found to be reliable and sensitive for estimating the LRCT for acridine to D. magna. (RJC)

  19. Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna.

    PubMed

    Bahrndorff, Simon; Michaelsen, Thomas Yssing; Jensen, Anne; Marcussen, Laurits Faarup; Nielsen, Majken Elley; Roslev, Peter

    2016-07-01

    Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high-throughput methods for detecting sublethal effects. We have evaluated an automated infra-red (IR) light-based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2 Cr2 O7 at 15, 20 and 25 °C and 2,4-dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2 Cr2 O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12-18 h. A similar biphasic pattern was observed after 2,4-dichlorophenol exposure at 20 °C. EC50 values for 2,4-dichlorophenol and K2 Cr2 O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03-0.07 mg l(-1) h(-1) . EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high-throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26198804

  20. Age and exposure duration as a factor influencing Cu and Zn toxicity toward Daphnia magna.

    PubMed

    Muyssen, B T A; Janssen, C R

    2007-11-01

    Standardized toxicity tests are generally performed with juvenile test organisms, e.g., in Daphnia magna assays neonates<24 h old are used. The purpose of this research was to investigate the influence of a delayed exposure to Cu and Zn on population parameters and toxicity values derived from these endpoints. Juveniles (<24 h; T0) and 7-d old daphnids (T7) were exposed for 21 and 14 d, respectively. For Cu, juveniles were significantly more sensitive than 7d old organisms following acute (48 h) as well as chronic (14 d) exposure. After 14 d of exposure to 130 microg/L Cu, mortality was 80% and 10% in T0 and T7, respectively. Juveniles per surviving female at this concentration decreased by 78% and 14% compared to the control. 14 d-NOEC and LOEC values (based on juveniles per surviving female) were 75 and 90 microg/L Cu for T0 and both>130 microg/L for T7. For Zn, survival in T0 and T7 was similar. Although T7 organisms produced significantly more offspring, 14 d-NOEC and LOEC values were equal to those of T0, i.e., 80 and 115 microg/L, respectively. For Cu as well as for Zn effect concentrations based on 14 and 21 d exposure were similar (results from T0). It can be concluded that acute and chronic toxicity data obtained from juvenile D. magna are more sensitive or equally sensitive than obtained from 7d old organisms. As differences are observed between the two metals extrapolations of these conclusions to other toxicants and other aquatic species cannot be made without further investigation. PMID:17258805

  1. Defeminization in Daphnia magna: A screening test for endocrine-disruptors in the environment?

    SciTech Connect

    Gerritsen, A.A.M.; Hoeven, N. van der

    1995-12-31

    Long term consequences associated with exposure to endocrine disrupting chemicals in the environment have been found in mammals, birds, fish, turtles and gastropods. Despite their important role, however, hardly any attention has been paid to the long term effects of such chemicals on crustaceans. Experiments originally carried out to quantify the ability of Daphnia magna to recover from short term exposure to para-tert-pentylphenol, revealed the endocrine disrupting properties of the test compound. During one of the experiments animals were divided into six (8 hour) age groups between 0 and 48 hours and exposed to 6 mg of para-tert-pentylphenol 1{sup {minus}1} for a period of 8 hours. Within the age groups of 16 to 24 and of 24 to 32 hours old 51 and 70% of the females respectively lag-fed behind in growth and showed reduced fertility. In addition to this, about 37 and 16% of these females showed malformations suggesting defeminization. The males showed no delay in growth and had no malformations. Furthermore, in terms of survival the males were shown to be less sensitive towards the test compound than the females. The type of effects in females and the sharp distinction between the effects on males and females are indicative for the estrogenicity of para-tert-pentylphenol. The estrogenic effects of a number alkylphenols, including para-tert-pentylphenol, were demonstrated in rats and confirmed in tests with the human breast cell MCF7. To the best of knowledge estrogenicity has not been recorded before for any chemical for any crustacean. The observation of estrogenic effects in D. magna opens up the way to a standardized test for screening chemicals with potentially endocrine disrupting properties. Such a test may be a valuable tool in environmental risk assessment and conservation of environmental and human health.

  2. Liposomes as an alternative delivery system for investigating dietary metal toxicity to Daphnia magna.

    PubMed

    Evens, Roel; De Schamphelaere, Karel A C; Balcaen, Lieve; Wang, Yingying; De Roy, Karen; Resano, Martín; Flórez, María del Rosario; Van der Meeren, Paul; Boon, Nico; Vanhaecke, Frank; Janssen, Colin R

    2011-10-01

    Dietary metal toxicity studies with invertebrates such as Daphnia magna are often performed using metal-contaminated algae as a food source. A drawback of this approach is that it is difficult to distinguish between the direct toxicity of the metal and indirect effects caused by a reduced essential nutrient content in the metal-contaminated diet, due to prior exposure of the algae to the metal. This hampers the study of the mechanisms of dietary metal toxicity in filter-feeding freshwater invertebrates. The aim of the present study was to develop a technique for producing metal-contaminated liposomes as an alternative delivery system of dietary metals. These liposomes are not vulnerable to metal-induced shifts in nutrient quality. Liposomes were prepared by the hydration of phosphatidylcholine in media containing either 0 (control) or 50mg Ni/L. The liposomes had average diameters of 19.31 (control) and 10.48 μm (Ni-laden), i.e., a size appropriate for ingestion by D. magna. The liposome particles were then mixed with uncontaminated green algae in a 1/10 ratio (on a dry wt. basis) to make up two diets that differed in Ni content (i.e., 2.0 μg Ni/g dry wt. in the control and 144.2 μg Ni/g dry wt. in the Ni-contaminated diet, respectively). This diet was then fed to D. magna during a 21-day chronic bioassay. The experiment showed that the Ni content and the size distribution of the liposomes were stable for at least 7 days. Also the use of phosphatidylcholine as a liposome component did not affect the reproduction of the daphnids. Exposure to increased level of dietary Ni resulted in 100% mortality after 14 days of exposure and in an increased whole-body Ni concentration in D. magna of 14.9 and 20.4 μg Ni/g dry wt. after 7 and 14 days of exposure, respectively. The Ni-exposed daphnids also exhibited a reduced size (i.e., 30% smaller than the control) after 7 days and a completely halted growth between day 7 and day 14. In terms of reproduction, the size of the

  3. Environmental effects of dredging. Use of daphnia magna to predict consequences of bioaccumulation

    SciTech Connect

    1987-03-01

    Results reported herein represent a portion of the laboratory research evaluating the relationship between mercury and cadmium tissue residues and biological effects in the freshwater crustacean, Daphnia magna (commonly known as the water flea). Procedures presented here for a 28-day Daphnia magna toxicity test could be used in screening for water-column toxicity resulting from open-water disposal of a specific dredged material. As a part of its regulatory and dredging programs, the U. S. Army Corps of Engineers often conducts, or requires to be conducted, an assessment of the potential for bioaccumulation of environmental contaminants from sediment scheduled for dredging and open-water disposal. There is, at present, no generally accepted guidance available to aid in the interpretation of the biological consequences of bioaccumulation. To provide an initial basis for such guidance, the Environmental Laboratory is conducting both literature database analyses and experimental laboratory studies as part of the Long-Term Effects of Dredging Operations (LEDO) Program.

  4. Chronic toxicity of diphenhydramine hydrochloride and erythromycin thiocyanate to Daphnia, Daphnia magna, in a continuous exposure test system

    USGS Publications Warehouse

    Meinertz, J.R.; Schreier, T.M.; Bernardy, J.A.; Franz, J.L.

    2010-01-01

    Diphenhydramine hydrochloride (DH; Benadryl TM, an over-the-counter antihistamine) and erythromycin thiocyanate (ET; a commonly used macrolide antibiotic) are pharmaceutical compounds whose chronic toxicity to Daphnia magna had not been characterized. Continuous exposure to DH concentrations about 5 times greater than the maximum reported environmental concentration of 0.023 lg/L for 21 days or to ET concentrations about 40 times the maximum reported environmental concentration of 6 (mu or u)g/L for 21 days did not significantly impact D. magna survival and production. In this study the no observable effect concentration for DH was 0.12 (mu or u)g/L and for ET was 248 (mu or u)g/L.

  5. Arginine kinase in the cladoceran Daphnia magna: cDNA sequencing and expression is associated with resistance to toxic Microcystis.

    PubMed

    Lyu, Kai; Zhang, Lu; Zhu, Xuexia; Cui, Guilian; Wilson, Alan E; Yang, Zhou

    2015-03-01

    Nutrient loading derived from anthropogenic activities into lakes have increased the frequency, severity and duration of toxic cyanobacterial blooms around the world. Although herbivorous zooplankton are generally considered to be unable to control toxic cyanobacteria, populations of some zooplankton, including Daphnia, have been shown to locally adapt to toxic cyanobacteria and suppress cyanobacterial bloom formation. However, little is known about the physiology of zooplankton behind this phenomenon. One possible explanation is that some zooplankton may induce more tolerance by elevating energy production, thereby adding more energy allocation to detoxification expenditure. It is assumed that arginine kinase (AK) serves as a core in temporal and spatial adenosine triphosphate (ATP) buffering in cells with high fluctuating energy requirements. To test this hypothesis, we studied the energetic response of a single Daphnia magna clone exposed to a toxic strain of Microcystis aeruginosa, PCC7806. Arginine kinase of D. magna (Dm-AK) was successfully cloned. An ATP-gua PtransN domain which was described as a guanidine substrate specificity domain and an ATP-gua Ptrans domain which was responsible for binding ATP were both identified in the Dm-AK. Phylogenetic analysis of AKs in a range of arthropod taxa suggested that Dm-AK was as dissimilar to other crustaceans as it was to insects. Dm-AK transcript level and ATP content in the presence of M. aeruginosa were significantly lower than those in the control diet containing only the nutritious chlorophyte, Scenedesmus obliquus, whereas the two parameters in the neonates whose mothers had been previously exposed to M. aeruginosa were significantly higher than those of mothers fed with pure S. obliquus. These findings suggest that Dm-AK might play an essential role in the coupling of energy production and utilization and the tolerance of D. magna to toxic cyanobacteria. PMID:25575127

  6. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans (journal version)

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-01-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund-site soils on freshwater invertebrates. These two species were used successfully in acute sediment tests and were shown to be useful in chronic tests in water.

  7. Chronic effects of contaminated sediment on Daphnia magna and Chironomus tentans

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.

    1988-10-01

    Chronic tests were conducted with Daphnia magna (cladoceran) and Chironomus tentans (midge) to determine their usefulness as test organisms for chronic sediment assays, and to estimate the potential long-term impact of contaminated freshwater sediments and contaminated Superfund site soils on freshwater invertebrates. These two species have been used successfully in acute sediment tests, and have been shown to be useful in chronic tests in water--only bioassays.

  8. The sensitivity of Daphnia magna and Daphnia curvirostris to 10 veterinary antibacterials and to some of their binary mixtures.

    PubMed

    Dalla Bona, Mirco; Di Leva, Vincenzo; De Liguoro, Marco

    2014-11-01

    Aim of this study was to evaluate the suitability of Daphnia curvirostris for the acute toxicity test usually performed on Daphnia magna, and to compare the sensitivity of the two species toward 10 antibacterials [enrofloxacin (EFX), ciprofloxacin(CPX), sulfaguanidine (SGD), sulfadiazine (SDZ), sulfamethazine (SMZ), sulfaquinoxaline (SQO), sulfaclozine (SCZ), sulfamerazine (SMA), sulfadimethoxine (SDM) and trimethoprim (TMP)] and some of their binary mixtures. Furthermore, a tentative prolonged-toxicity test (lasting 13d) was settled up in order to evidence toxic responses with drug concentrations that were uneffective in the classic 48h immobilization test. Results showed that D. curvirostris was more sensitive than D. magna to the majority of compounds (6 out of 10). Lowest 48h EC50s were obtained with EFX (4.3mgL(-1) in D. curvirostris) and SGD (6.2mgL(-1) in D. magna). The toxicity of paired compounds was always concentration-additive or less than concentration-additive. In the prolonged-toxicity test mortality and/or reproduction inhibition were constantly observed. It was concluded that: (1) D. curvirostris could be a suitable model for the evaluation of acute toxicity of antibacterials since its sensitivity was generally greater than that of D. magna; (2) the toxicity of EFX and SGD should be given special attention as the two compounds, in the prolonged test, showed to be active at concentrations of 0.9mgL(-1) and 2.5mgL(-1), respectively; (3) the concentration addition is usually a reasonable worst case estimation of the environmental impact of antibacterial mixtures. PMID:24630458

  9. Toxicity and accumulation of Cu and ZnO nanoparticles in Daphnia magna.

    PubMed

    Xiao, Yinlong; Vijver, Martina G; Chen, Guangchao; Peijnenburg, Willie J G M

    2015-04-01

    There is increasing recognition that the wide use of nanoparticles, such as Cu (CuNPs) and ZnO nanoparticles (ZnONPs), may pose risks to the environment. Currently there is insufficient insight in the contribution of metal-based nanoparticles and their dissolved ions to the overall toxicity and accumulation. To fill in this gap, we combined the fate assessment of CuNPs and ZnONPs in aquatic test media with the assessment of toxicity and accumulation of ions and particles present in the suspensions. It was found that at the LC50 level of Daphnia magna exposed to the nanoparticle suspensions, the relative contributions of ions released from CuNPs and ZnONPs to toxicity were around 26% and 31%, respectively, indicating that particles rather than the dissolved ions were the major source of toxicity. It was additionally found that at the low exposure concentrations of CuNPs and ZnONPs (below 0.05 and 0.5 mg/L, respectively) the dissolved ions were predominantly accumulated, whereas at the high exposure concentrations (above 0.1 mg/L and 1 mg/L, respectively), particles rather than the released ions played a dominant role in the accumulation process. Our results thus suggest that consideration on the contribution of dissolved ions to nanoparticle toxicity needs to be interpreted with care. PMID:25785366

  10. Identification of chemical-specific protein profiles in Daphnia magna using neural networks

    SciTech Connect

    Iamonte, T.; Broadt, T.; Bradley, B.

    1995-12-31

    One dimensional gel electrophoresis was performed on whole-animal homogenates of 10 Daphnia magna exposed for 48 hours to one toxic and one non-toxic concentration of 2,4-dinitrophenol and sodium pentachlorophenate, two uncouplers of oxidative phosphorylation; malathion, an organophosphate; and permethrine, a pyrethroid, along with culture water and solvent controls, as appropriate. Ten randomized complete block exposures were conducted to minimize among-cohort variability. The 10-animal samples were gel electrophoresed, visualized using neutral silver staining and digitized with a Molecular Dynamics personal laser densitometer equipped with ImageQuant software. Densitometric data were used in a commercial neural network software package to construct a learning set, or database, of the protein profiles induced by the known chemical treatments. Novel data sets were then presented to the neural network program for assignment to treatment categories. Although no differences in protein profile between controls and chemical treatments and among chemical treatments could be detected visually in one dimensional gels, the neural network was able to correctly assign each sample to the appropriate learned treatment category about 70 percent of the time. Key proteins used by the neural network software to learn the protein profile of each chemical were identified by molecular weight and assigned a relative importance for identification of that chemical.

  11. Pentachlorophenol disrupts steroid hormone metabolism at concentrations that reduce survival and fecundity of Daphnia magna

    SciTech Connect

    Parks, L.G.; LeBlanc, G.A.

    1995-12-31

    Alterations in steroid metabolism by environmental endocrine disrupters can significantly affect steroid hormone-dependent processes such as growth and reproduction. Exposure to pentachlorophenol (PCP) has been shown to elicit a variety of endocrine-related adverse effects. The present study was undertaken to establish whether concentrations of PCP that adversely affect survival, growth, or reproduction of Daphnia magna during chronic exposure also elicit changes in steroid hormone metabolism. Survival and/or reproduction of daphnids was significantly reduced from exposure to 1.0, 0.50 and 0.25 mg/L PCP. Following chronic exposure to PCP, daphnids were incubated with [{sup 14}C]testosterone and the testosterone metabolites eliminated were identified and quantified. The rate of testosterone hydroxyl-metabolite elimination was not significantly different from controls. However, elimination of two of the glucose-conjugated metabolites of testosterone decreased in a PCP concentration-dependent manner. Adult daphnids were next exposed to these concentrations of PCP for only 48 hours and effects on steroid metabolism assessed. As observed following chronic exposure, PCP had no effect on the elimination of hydroxyl-metabolites. However, elimination of glucose and sulfate conjugates of testosterone were inhibited in a concentration-dependent manner. These results demonstrate that, (1) PCP alters steroid biotransformation activities at concentrations that affect survival and reproduction, and (2) effects on steroid metabolism can be detected following short-term exposure to PCP. Thus, this biochemical parameter may serve as a biomarker of chronic toxicity associated with PCP.

  12. Relationship between solubility and toxicity of coal liquefaction materials to the freshwater crustacean, Daphnia magna

    SciTech Connect

    Dauble, D.D.; Gray, R.H.; Scott, A.J.; Thomas, B.L.

    1985-11-01

    The potential ecological risk from complex coal liquids that may be released to freshwater ecosystems is ultimately dependent on both the degree of solubility of parent material and the toxic properties of constitutent compounds that an organism is exposed to. Thus, highly water-soluble components that remain bioavailable and are present in the water column at acutely toxic concentrations pose a problem for many aquatic organisms. We screened coal liquids derived from several processes and under different process designs to evaluate the acute toxicity of their water-soluble fractions (WSFs) to Daphnia magna. The solubility of materials treated varied and WSFs ranged from 44 to 2260 mg/L total carbon (TC). The most soluble materials in water exhibited greater toxicity based on percent dilution of the WSF. However, toxicity was similar for all materials tested when based on soluble components (TC in solution). Chemical characterization of the WSFs indicated that phenols comprised the majority of the TC in solution. Because toxicity based on total phenols was generally greater than that for individual phenolics tested separately, other soluble chemical classes in the complex mixtures likely contribute to observed toxicity.

  13. Role of soluble zinc in ZnO nanoparticle cytotoxicity in Daphnia magna: A morphological approach.

    PubMed

    Bacchetta, Renato; Maran, Barbara; Marelli, Marcello; Santo, Nadia; Tremolada, Paolo

    2016-07-01

    The role of soluble zinc has been determined in Daphnia magna by a morphological approach, integrating a previous paper in which the ultrastructural damages to gut epithelial cells have been studied after ZnO nanoparticles exposure. In the present paper, the toxicity and morphological effects of soluble zinc from ZnSO4 have been determined in a 48-h acute exposure test. Daphnids have been exposed to six nominal zinc concentrations (0.075, 0.15, 0.3, 0.6, 1.2, and 2.4mg Zn/L) and then fixed for microscopic analyses. Data from the acute toxicity tests gave an EC50 value of 0.99mg/L and showed that no immobilization appeared up to 0.3mg Zn/L. Ultrastructural analyses of samples from the two highest concentrations showed large vacuolar structures, swelling of mitochondria, multilamellar bodies, and a great number of autophagy vacuoles. These findings have been compared to those from our previous study, and similarities and/or differences discussed. Based on the overall results it can be concluded that dissolved zinc ions played a key role in ZnO nanoparticle toxicity and that the morphological approach is an extremely useful tool for comparing toxicological effects as well. A possible common toxic mechanism of soluble zinc and ZnO nanoparticles was also proposed. PMID:27131075

  14. Growth Retardation and Altered Isotope Composition As Delayed Effects of PCB Exposure in Daphnia magna.

    PubMed

    Ek, Caroline; Gerdes, Zandra; Garbaras, Andrius; Adolfsson-Erici, Margaretha; Gorokhova, Elena

    2016-08-01

    Trophic magnification factor (TMF) analysis employs stable isotope signatures to derive biomagnification potential for environmental contaminants. This approach relies on species δ(15)N values aligning with their trophic position (TP). This, however, may not always be true, because toxic exposure can alter growth and isotope allocation patterns. Here, effects of PCB exposure (mixture of PCB18, PCB40, PCB128, and PCB209) on δ(15)N and δ(13)C as well as processes driving these effects were explored using the cladoceran Daphnia magna. A two-part experiment assessed effects of toxic exposure during and after exposure; juvenile daphnids were exposed during 3 days (accumulation phase) and then allowed to depurate for 4 days (depuration phase). No effects on survival, growth, carbon and nitrogen content, and stable isotope composition were observed after the accumulation phase, whereas significant changes were detected in adults after the depuration phase. In particular, a significantly lower nitrogen content and a growth inhibition were observed, with a concomitant increase in δ(15)N (+0.1 ‰) and decrease in δ(13)C (-0.1 ‰). Although of low magnitude, these changes followed the predicted direction indicating that sublethal effects of contaminant exposure can lead to overestimation of TP and hence underestimated TMF. PMID:27367056

  15. Identification of multiple steroid hydroxylases in Daphnia magna and their modulation by xenobiotics

    SciTech Connect

    Baldwin, W.S.; LeBlanc, G.A. . Dept. of Toxicology)

    1994-07-01

    Steroid hydroxylase activities were characterized in Daphnia magna and evaluated for potential use as biomarkers of xenobiotic exposure. Microsomes prepared from Daphnia magna generated as single NADPH-dependent metabolite of [[sup 14]C] testosterone. However, intact daphnids excreted at least 10 polar metabolites of [[sup 14]C] testosterone into the test medium. Six of these metabolites were identified as 2[alpha]-, 16[beta]-, 6[beta]-, 6[alpha]-, 7[alpha]-, and 15[alpha]-[[sup 14]C]hydroxytestosterone. The unidentified metabolites are also presumed to be hydroxylated products of testosterone, based on their relative migrations during TLC. The inefficient metabolism of [[sup 14]C] testosterone during the in vitro microsomal incubations may have been due to the release of P450 inhibitors during microsome preparation. Exposure of daphnids to the P450 modulators phenobarbital, [beta]-naphthoflavone, piperonyl butoxide, and malathion differentially inhibited the steroid hydroxylase activities. Results from this study indicate that Daphnia magna expresses several P450 enzymes and that these enzymes are differentially modulated by xenobiotic exposure. Steroid hydroxylase activities may serve not only as a biomarker of toxicant exposure, but also as a predictor of toxicant effects involving perturbations of steroid hormone homeostasis.

  16. Role of B-esterases in assessing toxicity of organophosphorus (chlorpyrifos, malathion) and carbamate (carbofuran) pesticides to Daphnia magna.

    PubMed

    Barata, Carlos; Solayan, Arun; Porte, Cinta

    2004-02-10

    In this study, the cladoceran Daphnia magna was exposed to two model organophosphorous and one carbamate pesticides including malathion, chlorpyrifos and carbofuran to assess acetylcholinesterase (AChE) and carboxylesterase (CbE) inhibition and recovery patterns and relate those responses with individual level effects. Our results revealed differences in enzyme inhibition and recovery patterns among the studied esterase enzymes and pesticides. CbE was more sensitive to organophosphorous than AChE, whereas both CbE and AChE showed equivalent sensitivities to the carbamate carbofuran. Recovery patterns of AChE and CbE activities following exposure to the studied pesticides were similar with 80-100% recoveries taking place 12 and 96 h after exposure to organophosphorous and carbamates pesticides, respectively. The physiological role of AChE and CbE inhibition patterns in Daphnia was examined by using organophosphorous and carbamate compounds alone and with specific inhibitors of CbE. Under exposure to organophosphorous pesticides, survival of Daphnia juveniles was impaired at AChE inhibition levels higher than 50% whereas under exposure to the carbamate carbofuran low levels of AChE inhibition affected mortality. Inhibition of CbE by 80-90% increased toxicity to organophosphorous and carbamate pesticides by up to two- and four-fold, respectively. Our results suggest that both AChE and CbE enzymes are involved in determining toxicity of Daphnia to the studied chemicals and that AChE inhibition levels higher than 50% can be considered of environmental concern to Daphnia species. PMID:15036868

  17. Effects of He-Ne laser on Daphnia magna Straus manifested in subsequent generations

    NASA Astrophysics Data System (ADS)

    Vorob'yeva, O. V.; Filenko, O. F.; Isakova, E. F.; Vorobieva, N. N.; Rybaltovskii, A. O.; Yusupov, V. I.; Bagratashvili, V. N.

    2015-11-01

    The effects of He-Ne laser irradiation (including visible laser light 632.8 nm in wavelength and an attendant electromagnetic field from the laser apparatus) on the fertility, newborn quality and linear dimensions of the body of Cladocera Daphnia magna Straus were determined. It is shown that the attendant electromagnetic field generated by the laser apparatus can have significant impact on the results of low-intensity laser therapy. The laser light exposure of daphnia to a dose range of 1.7-1300 mJ cm-2 stimulates the integral functions of the daphnia’s body. At the same time, the attendant electromagnetic field (72 mA m-1 in the frequency range of 0.02-20 kHz and 400 mA m-1 in the frequency range of 3-4 MHz) causes the appearance of quickly dying and/or abnormal newborn (up to a small percent) that has never been observed in the control. Anomalies of daphnia mainly consisted of swimming antenna pathologies. Moreover, under the influence of the attendant electromagnetic field on parental daphnia only, these anomalies appear even in several subsequent generations of newborn. The negative impact on daphnia disappears completely after the suppression of the attendant electromagnetic field to laboratory background level. It is shown that laser light can partially compensate the negative impact of the attendant electromagnetic field on Daphnia.

  18. Toxicity of various silver nanoparticles compared to silver ions in Daphnia magna

    PubMed Central

    2012-01-01

    Background To better understand the potential ecotoxicological impacts of silver nanoparticles released into freshwater environments, the Daphnia magna 48-hour immobilization test was used. Methods The toxicities of silver nitrate, two types of colloidal silver nanoparticles, and a suspension of silver nanoparticles were assessed and compared using standard OECD guidelines. Also, the swimming behavior and visible uptake of the nanoparticles by Daphnia were investigated and compared. The particle suspension and colloids used in the toxicity tests were well-characterized. Results The results obtained from the exposure studies showed that the toxicity of all the silver species tested was dose and composition dependent. Plus, the silver nanoparticle powders subsequently suspended in the exposure water were much less toxic than the previously prepared silver nanoparticle colloids, whereas the colloidal silver nanoparticles and AgNO3 were almost similar in terms of mortality. The silver nanoparticles were ingested by the Daphnia and accumulated under the carapace, on the external body surface, and connected to the appendages. All the silver species in this study caused abnormal swimming by the D. magna. Conclusion According to the present results, silver nanoparticles should be classified according to GHS (Globally Harmonized System of classification and labeling of chemicals) as "category acute 1" to Daphnia neonates, suggesting that the release of nanosilver into the environment should be carefully considered. PMID:22472056

  19. Competition impedes the recovery of Daphnia magna from repeated insecticide pulses.

    PubMed

    Dolciotti, Ida; Foit, Kaarina; Herkelrath, Anna; Liess, Matthias

    2014-02-01

    The effects of multiple insecticide pulses on non-target organisms have rarely been investigated in combination with relevant biotic interactions, such as competition. In this study, we examined the effects of two repeated pulses of the insecticide pirimicarb (3, 10, 24 μg/L) on populations of Daphnia magna with or without competition. To investigate the influence of competition, half of the test systems were supplemented with the pirimicarb-insensitive species Culex pipiens. The pesticide pulses were followed by a recovery period of 28 days, which corresponded to approximately three generation times for D. magna. The one-species setup with the Daphnia populations and the two-species setup with both the Daphnia and Culex populations had a precontamination period of 30 days so that intra- and interspecific competitions were present prior to the insecticide pulse. Short-term effects on the survival of the Daphnia population were observed in both setups immediately after each insecticide pulse at the highest concentration level. In the one-species setup, the short-term effects on population survival were increased by intraspecific competition. However, the Daphnia populations in the one-species setup recovered and reached the control level within approximately two weeks after each insecticide pulse. In contrast, in the two-species setup at the highest concentration, we observed culmination of insecticide effects: the Daphnia populations did not recover and their abundance was below the control level until the end of the observation time. Their recovery was impeded by the presence of the competing species C. pipiens for at least four weeks. At low concentrations, no culmination of effects was observed. We conclude that repeated toxicant pulses on populations that are challenged with interspecific competition may result in a multigenerational culmination of toxicant effects. PMID:24373889

  20. Chronic toxicity of erythromycin thiocyanate to Daphnia magna in a flow-through, continuous exposure test system

    USGS Publications Warehouse

    Meinertz, J.R.; Schreier, T.M.; Bernardy, J.A.

    2011-01-01

    Approval of a new animal drug application for AQUAMYCIN 100?? (erythromycin thiocyanate; ET) to treat freshwater salmonid species with bacterial kidney disease is being pursued in the US. As part of the approval process, ETs impact on an aquatic environment had to be described in an environmental assessment. The environmental assessment was lacking data to characterize the effect ET would have on a chronically exposed aquatic invertebrate organism. A major step to fulfilling the environmental assessment was completed after conducting a comprehensive study continuously exposing Daphnia magna to ET for 21 days. Results indicated that the no observable effect concentration for ET was 179 ??g/L. ?? 2011 Springer Science+Business Media, LLC (outside the USA).

  1. Combined experimental and theoretical study on photoinduced toxicity of an anthraquinone dye intermediate to Daphnia magna.

    PubMed

    Wang, Ying; Chen, Jingwen; Lin, Jing; Wang, Zhen; Bian, Haitao; Cai, Xiyun; Hao, Ce

    2009-04-01

    The toxicity of chemicals can be enhanced by light through two photochemical pathways: Photomodification to more toxic substances and photosensitization. In the present study, the reactive oxygen species (ROS) mechanism for photoinduced acute toxicity of 1-amino-2,4-dibromoanthraquinone (ADBAQ) to Daphnia magna was clarified by experiment and theoretical calculation. The results of the present study show that ADBAQ exhibited high toxicity to D. magna under simulated solar radiation (SSR), with a median effective concentration of 1.23 +/- 0.19 nM (mean +/- standard deviation). The photomodified ADBAQ (mixtures of ADBAQ and its photoproducts) was less phototoxic than the intact ADBAQ. The SSR-only or ADBAQ-only treatments did not affect the ROS level in D. magna, whereas increased ROS levels were observed in the presence of SSR and ADBAQ. The ROS in vivo were determined by measuring the fluorescence of 2',7'-dichlorofluorescein, which is a useful technique to assess toxicity of chemicals to aquatic organisms. The antioxidants, including vitamin C, vitamin E, and beta-carotene, decreased the photoinduced oxidative damage to D. magna, probably by scavenging ROS. These experimental results demonstrate that photosensitization is the potential mechanism of photoinduced toxicity of ADBAQ to D. magna. Proposed phototoxic pathways of ADBAQ were elucidated by means of time-dependent density functional theory. The theoretical calculation indicates that superoxide anion and singlet oxygen are able to be generated through electron transfer or energy transfer in the photosensitization reactions. PMID:19391687

  2. Reduced fitness of Daphnia magna fed a Bt-transgenic maize variety.

    PubMed

    Bøhn, Thomas; Primicerio, Raul; Hessen, Dag O; Traavik, Terje

    2008-11-01

    Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize. PMID:18347840

  3. Survival of daphnia magna and hyalella azteca in cadmium-spiked water and sediment

    SciTech Connect

    Nebeker, A.V.; Onjukka, S.T.; Cairns, M.A.; Krawczyk, D.F.

    1986-01-01

    Freshwater sediments and water were spiked with cadmium (Cd) in the laboratory, and toxicity tests were conducted with the cladoceran Daphnia magna and the amphipod Hyalella azteca to determine if Cd in the sediment would cause increased toxicity. The 48-h LC50 values for Daphnia in tests without sediment were 36, 33, 24, and 40 micrograms/L total Cd. Calculated free-ion (Cd/sup 2 +/)LC50 values for the same tests were 28, 25, 18 and 31 micrograms/L. LC50 values (48-h) determined for total Cd(uncentrifuged water sample) in the sediment-containing beakers were 252, 69, and 122 micrograms/L for Daphnia. LC50 values for dissolved Cd(centrifuged 10,000 rpm) in the sediment-containing beakers were 61, 27, and 100 micrograms/L for Daphnia. Higher total Cd LC50 values indicate that Cd adsorbed to soluble organic material was not biologically available. No significant mortality of Daphnia or Hyalella occurred in the flow-through tests in which sediment contained the same levels of Cd as in the static tests. Mortality was similar in beakers with and without Cd-spiked sediment, indicating that Cd in the sediment and adsorbed to organic materials was not available to cause increased mortality.

  4. Acute toxicity of binary and ternary mixtures of Cd, Cu, and Zn to Daphnia magna.

    PubMed

    Meyer, Joseph S; Ranville, James F; Pontasch, Mandee; Gorsuch, Joseph W; Adams, William J

    2015-04-01

    Standard static-exposure acute lethality tests were conducted with Daphnia magna neonates exposed to binary or ternary mixtures of Cd, Cu, and Zn in moderately hard reconstituted water that contained 3 mg dissolved organic carbon/L added as Suwannee River fulvic acid. These experiments were conducted to test for additive toxicity (i.e., the response to the mixture can be predicted by combining the responses obtained in single-metal toxicity tests) or nonadditive toxicity (i.e., the response is less than or greater than additive). Based on total metal concentrations (>90% dissolved) the toxicity of the tested metal mixtures could be categorized into all 3 possible additivity categories: less-than-additive toxicity (e.g., Cd-Zn and Cd-Cu-Zn mixtures and Cd-Cu mixtures when Cu was titrated into Cd-containing waters), additive toxicity (e.g., some Cu-Zn mixtures), or more-than-additive toxicity (some Cu-Zn mixtures and Cd-Cu mixtures when Cd was titrated into Cu-containing waters). Exposing the organisms to a range of sublethal to supralethal concentrations of the titrated metal was especially helpful in identifying nonadditive interactions. Geochemical processes (e.g., metal-metal competition for binding to dissolved organic matter and/or the biotic ligand, and possibly supersaturation of exposure waters with the metals in some high-concentration exposures) can explain much of the observed metal-metal interactions. Therefore, bioavailability models that incorporate those geochemical (and possibly some physiological) processes might be able to predict metal mixture toxicity accurately. PMID:25336231

  5. Evidence for links between feeding inhibition, population characteristics, and sensitivity to acute toxicity for Daphnia magna.

    PubMed

    Agatz, Annika; Brown, Colin D

    2013-08-20

    A population experiment with Daphnia magna tested the hypothesis that short-term feeding inhibition provokes a shift in population structure that will vary with conspecific pressure (e.g., pressure occurring from individuals of the same species due to competition for food and space) and increases population sensitivity to a xenobiotic exposure due to size-dependent toxicity (e.g., decreasing sensitivity with increasing body length). Populations were exposed for one week to a feeding inhibitor (imidacloprid, 0.15 or 12.0 mg/L) followed by one week of recovery and one day of exposure to an acute toxin (carbaryl, 0.0098 mg/L). Identical exposure under low and high conspecific pressure was studied by delaying the start of exposure for half of the populations by two weeks; thus populations were in a different stage of population development when exposure occurred. Feeding inhibition of 97% (12.0 mg/L imidacloprid) caused a shift in population structure toward smaller individuals but also reduced population abundance by up to 56 ± 7% with a strong influence of conspecific pressure. Increased population sensitivity to carbaryl was observed after feeding inhibition of 97% as hypothesized. Carbaryl exposure for one day resulted in population decline of up to 23 ± 6% when populations were not previously exposed to imidacloprid. Identical carbaryl exposure provoked a four times stronger decline in population abundance when exposure occurred following feeding inhibition of 97%. In conflict with the hypothesis, this was at least in part due to changes in the reproductive strategy of daphnids following exposure to imidacloprid rather than driven by the shift in population structure. The differences in population sensitivity to additional stress (carbaryl) occurring one week after feeding inhibition caused by exposure to imidacloprid adds a further challenge to understanding potential impacts from multiple stressors as occurring in the field at the population level. PMID

  6. Adsorption, uptake and distribution of gold nanoparticles in Daphnia magna following long term exposure.

    PubMed

    Botha, Tarryn Lee; Boodhia, Kailen; Wepener, Victor

    2016-01-01

    Gold nanoparticles (nAu) have recently been studied and developed within the biological and photothermal therapeutic contexts. The major clinical interest is within the application of novel drug delivery systems. Environmental exposure to nanoparticles can occur in different stages of the lifecycle of the product; from their synthesis, applications, product weathering and their disposal. Freshwater Daphnids, specifically Daphnia magna, have been used since the 1960s as a standard species in acute and chronic aquatic toxicity testing. Visualization of the interactions and uptake of nAu by D. magna was related to reproduction and molting patterns. Exposure to nAu was done using a chronic reproduction test performed for 14 days at six concentrations (0.5mg/L, 2mg/L, 5mg/L, 10mg/L, 15mg/L and 20mg/L). Microscopy was used to determine whether there was any uptake or interaction of nAu with daphnia. However the concentration of nAu in the media and the charge of particles played a role in the uptake and surface adsorption. As exposure concentrations of nAu increased it appeared that the nAu aggregated onto the surface and in the gut of the organisms in higher concentrations. There was no evidence of nAu internalization into the body cavity of the daphnia. Aquatic exposure to nAu resulted in increased adhesion of the particles to the carapace of daphnia, ingestion and uptake into the gut of daphnia and had no significant effect on reproduction and molting patterns. PMID:26650707

  7. Effect of nutrient limitation of cyanobacteria on protease inhibitor production and fitness of Daphnia magna.

    PubMed

    Schwarzenberger, Anke; Sadler, Thomas; Von Elert, Eric

    2013-10-01

    Herbivore-plant interactions have been well studied in both terrestrial and aquatic ecosystems as they are crucial for the trophic transfer of energy and matter. In nutrient-rich freshwater ecosystems, the interaction between primary producers and herbivores is to a large extent represented by Daphnia and cyanobacteria. The occurrence of cyanobacterial blooms in lakes and ponds has, at least partly, been attributed to cyanotoxins, which negatively affect the major grazer of planktonic cyanobacteria, i.e. Daphnia. Among these cyanotoxins are the widespread protease inhibitors. These inhibitors have been shown (both in vitro and in situ) to inhibit the most important group of digestive proteases in the gut of Daphnia, i.e. trypsins and chymotrypsins, and to reduce Daphnia growth. In this study we grew cultures of the cyanobacterium Microcystis sp. strain BM25 on nutrient-replete, N-depleted or P-depleted medium. We identified three different micropeptins to be the cause for the inhibitory activity of BM25 against chymotrypsins. The micropeptin content depended on nutrient availability: whereas N limitation led to a lower concentration of micropeptins per biomass, P limitation resulted in a higher production of these chymotrypsin inhibitors. The altered micropeptin content of BM25 was accompanied by changed effects on the fitness of Daphnia magna: a higher content of micropeptins led to lower IC50 values for D. magna gut proteases and vice versa. Following expectations, the lower micropeptin content in the N-depleted BM25 caused higher somatic growth of D. magna. Therefore, protease inhibitors can be regarded as a nutrient-dependent defence against grazers. Interestingly, although the P limitation of the cyanobacterium led to a higher micropeptin content, high growth of D. magna was observed when they were fed with P-depleted BM25. This might be due to reduced digestibility of P-depleted cells with putatively thick mucilaginous sheaths. These findings indicate that

  8. The induction of biochemical changes in Daphnia magna by CuO and ZnO nanoparticles.

    PubMed

    Mwaanga, Phenny; Carraway, Elizabeth R; van den Hurk, Peter

    2014-05-01

    Whilst a considerable number of studies have been reported on the acute toxicity of nanoparticles (NPs) on invertebrates such as Daphnia magna, few studies have been reported on the biochemical change (biomarkers) induction on these species by NPs, especially metal oxide NPs. The aim of this study was to investigate some biomarkers in D. magna induced by copper oxide (CuO) and zinc oxide (ZnO) NPs under controlled laboratory conditions. We exposed the 5 day old D. magna for 72 h to sublethal concentration of CuO and ZnO NPs in synthetic moderately hard water (MHW) with and without dissolved natural organic matter (NOM) and estimated the glutathione-S-transferase (GST) activity, formation of oxidized glutathione (GSSG), and amounts of thiobarbituric acid reacting substances (TBARS) and metallothionein (MT). Additionally, complementary short term dissolution studies on CuO and ZnO NPs were conducted. The results showed inactivation of GST enzyme by both metal oxide NPs. The results also showed increased production of oxidized GSH, increased generation of TBARS and increased induction of MT. In the presence of NOM, significant reduction (p<0.05) in these biochemical changes was observed. These results indicated that oxidative stress is one of the toxicity mechanisms for these metal oxide NPs. Furthermore, the results suggest that these metal oxide NPs compromise the health of D. magna, and possibly other aquatic organisms, and therefore have potential to affect ecosystem stability. The short term dissolution studies showed that the proportion of dissolved NPs is higher (1.2% and 70% of initial concentration for dissolved Cu and Zn, respectively) at low particle concentration and is lower (0.4% and 17% of initial concentration for dissolved Cu and Zn, respectively) at higher particle concentration. These results suggest that the observed toxicity may be caused by both metal oxide nanoparticles and metal ions dissociated from the nanoparticles. PMID:24699179

  9. Acute toxicity of leachates of tire wear material to Daphnia magna--variability and toxic components.

    PubMed

    Wik, Anna; Dave, Göran

    2006-09-01

    Large amounts of tire rubber are deposited along the roads due to tread wear. Several compounds may leach from the rubber and cause toxicity to aquatic organisms. To investigate the toxic effects of tire wear material from different tires, rubber was abraded from the treads of twenty-five tires. Leachates were prepared by allowing the rubber to equilibrate with dilution water at 44 degrees C for 72 h. Then the rubber was filtered from the leachates, and test organisms (Daphnia magna) were added. Forty-eight hour EC50s ranged from 0.5 to >10.0 g l(-1). The toxicity identification evaluation (TIE) indicated that non-polar organic compounds caused most of the toxicity. UV exposure of the filtered tire leachates caused no significant increase in toxicity. However, when tested as unfiltered leachates (the rubber was not filtered from the leachates before addition of D. magna) photo-enhanced toxicity was considerable for some tires, which means that test procedures are important when testing tire leachates for aquatic (photo) toxicity. The acute toxicity of tire wear for Daphnia magna was found to be <40 times a predicted environmental concentration based on reports on the concentration of a tire component found in environmental samples, which emphasizes the need for a more extensive risk assessment of tire wear for the environment. PMID:16466775

  10. Uptake, depuration, and bioconcentration of two pharmaceuticals, roxithromycin and propranolol, in Daphnia magna.

    PubMed

    Ding, Jiannan; Lu, Guanghua; Liu, Jianchao; Yang, Haohan; Li, Yi

    2016-04-01

    The objective of the present study was to investigate the uptake, depuration, and bioconcentration of two pharmaceuticals, roxithromycin (ROX) and propranolol (PRP), in Daphnia magna via aqueous exposure. Additionally, dietary and pH effects on the bioconcentration of two pharmaceuticals in daphnia were studied. During the 24-h uptake phase followed by the 24-h depuration phase, the uptake rate constants (k(u)) of ROX for daphnia were 9.21 and 2.77 L kg(-1) h(-1), corresponding to the exposure concentrations of 5 and 100 μg L(-1), respectively; For PRP at the nominal concentrations of 5 and 100 μg L(-1), k(u) were 2.29 and 0.99 L kg(-1) h(-1), respectively. The depuration rate constants (k(d)) of ROX in daphnia, at the exposure concentrations of 5 and 100 μg L(-1), were 0.0985 and 0.207 h(-1), respectively; while those of PRP were 0.0276 and 0.0539 h(-1) for the nominal concentrations of 5 and 100 μg L(-1), respectively. With the decreasing exposure concentrations, the bioconcentration factors (BCFs) in daphnia ranged from 13.4 to 93.5 L kg(-1) for ROX, and 18.4 to 83.0 L kg(-1) for PRP, revealing the considerable accumulation potential of these two pharmaceuticals. Moreover, after 6h exposure, the body burdens of ROX and PRP in dead daphnia were 4.98-6.14 and 7.42-12.9 times higher than those in living daphnia, respectively, implying that body surface sorption dominates the bioconcentration of the two pharmaceuticals in daphnia. In addition, the presence of algal food in the media could significantly elevate the kd values for both ROX and PRP, thereby restraining their bioconcentration in daphnia. A pH-dependent bioconcentration study revealed that the bioconcentration of the two pharmaceuticals in daphnia increased with increasing pH levels, which ranged from 7 to 9. Finally, a model was developed to estimate the relationships between pH and the BCFs of the two pharmaceuticals in zooplankton. The predicted values based on this model were highly consistent

  11. Effects of ectoine on behavioural, physiological and biochemical parameters of Daphnia magna.

    PubMed

    Bownik, Adam; Stępniewska, Zofia; Skowroński, Tadeusz

    2015-02-01

    Ectoine (ECT) is a compatible solute produced by soil, marine and freshwater bacteria in response to stressful factors. The purpose of our study was to determine the possible toxic influence of ECT on Daphnia magna. We determined the following endpoints: survival rate during exposure and recovery, swimming performance, heart rate, thoracic limb movement determined by image analysis, haemoglobin level by ELISA assay, catalase and nitric oxide species (NOx) by spectrophotometric methods. The results showed 80% survival of daphnids exposed to 50mg/L of ECT after 24h and 10% after 90h, however lower concentrations of ECT were well tolerated. A concentration-dependent reduction of swimming velocity was noted at 24 and 48h of the exposure. ECT (at 2.5 and 4mg/L) induced an increase of heart rate and thoracic limb movement (at 2.5, 4 and 20mg/L) after 24h. After 10h of the exposure to ECT daphnids showed a concentration-dependent increase of haemoglobin level synthesized and accumulated in the epipodite epithelia. After 24h we noted a concentration-dependent decrease of haemoglobin level and its lowest value was found after 48h of the exposure. ECT at a concentration of 20 and 25mg/L slightly stimulated catalase activity after 24h. NOx level was also increased after 10h of the exposure to 20 and 25mg/L of ECT reaching maximal activity after 24h. Our results suggest that ECT possesses some modulatory potential on the behaviour, physiology and biochemical parameters in daphnids. PMID:25460046

  12. Rapid Adaptation of a Daphnia magna Population to Metal Stress Is Associated with Heterozygote Excess.

    PubMed

    Hochmuth, Jennifer D; De Meester, Luc; Pereira, Cecília M S; Janssen, Colin R; De Schamphelaere, Karel A C

    2015-08-01

    Although natural populations can harbor evolutionary potential to adapt genetically to chemical stress, it is often thought that natural selection leads to a general reduction of genetic diversity and involves costs. Here, a 10 week microevolution experiment was conducted with a genetically diverse and representative sample of one natural Daphnia magna population that was exposed to copper and zinc. Both Cu- and Zn-selected populations developed a significantly higher metal tolerance (i.e., genetic adaptation), indicated by higher reproduction probabilities of clonal lines in Cu and Zn exposures than observed for the original and control populations. The complete recovery of the population densities after 10 weeks of Zn selection (following an initial decrease of 74%) illustrates an example of evolutionary rescue. Microsatellite genotyping revealed a decrease in clonal diversity but no change in allelic richness, and showed an excess in heterozygosity in the Cu- and Zn-selected populations compared to the control and original populations. The excess heterozygosity in metal-selected populations that we observed has important consequences for risk assessment, as it contributes to the maintenance of a higher allelic diversity under multigenerational chemical exposure. This study is, to our knowledge, the first report of an increase in heterozygosity following multigenerational exposure to metal stress, despite a decline in clonal diversity. In a follow-up study with the Zn-selected populations, we observed no effect of Zn selection on the tolerance to heat and cyanobacteria. However, we observed higher tolerance to Cd in the Zn-selected than in the original and control populations if the 20% effective concentration of Cd was considered (cross-tolerance). Our results suggest only limited costs of adaptation but future research is needed to evaluate the adaptive potential of metal-selected populations to novel stressors and to determine to what extent increased

  13. Acclimation to ultraviolet irradiation affects UV-B sensitivity of Daphnia magna to several environmental toxicants.

    PubMed

    Kim, Jungkon; Lee, Minjung; Oh, Sorin; Ku, Ja-Lok; Kim, Kyung-Hee; Choi, Kyungho

    2009-12-01

    Phototoxicity of several environmental contaminants by UV light has been reported in many studies. Nevertheless, field observations suggest the presence of certain defense mechanisms that would protect aquatic organisms against phototoxic damages. The current study was conducted to understand the responses of aquatic receptors to phototoxic chemicals in a natural environment where low dose UV light is present and long-term acclimation to UV might have been taken place. For this purpose, the water flea Daphnia magna was acclimated to a non-lethal, environmentally relevant level of UV-B light for >20 successive generations. The differences in toxicity response were evaluated between the UV-B acclimated and the non-acclimated daphnids when they were exposed to phototoxic compounds such as polynuclear aromatic hydrocarbons (fluoranthene and pyrene), a pharmaceutical (sulfathiazole), or metals (Cd and Cu) under UV-B light. Following the UV-B acclimation, toxicity of metals under UV-B light significantly decreased (P<0.1) suggesting the defense/repair system which might be developed through acclimation. For PAHs and sulfathiazole, however the acclimation rendered organisms more susceptible (P<0.05). The metabolic cost incurred during the acclimation to UV-B stress may in part explain the organisms' reduced capacity to deal with other stressors. Addition of vitamin C significantly increased the resistance of UV-B acclimated individuals against Cu, while no change was observed for the other chemicals, suggesting that the mode of Cu phototoxicity is different from those of the other phototoxicants under UV-B light. Two-dimensional gel electrophoresis analyses showed that long-term acclimation to UV-B lead to notable changes in protein expression, which may be further evaluated to explain varying susceptibilities of the acclimated daphnids to different phototoxicants. PMID:19836821

  14. Importance of surface coatings and soluble silver in silver nanoparticles toxicity to Daphnia magna.

    PubMed

    Zhao, Chun-Mei; Wang, Wen-Xiong

    2012-06-01

    Silver nanoparticles (AgNPs) are now widely used in antibacterial and personal care products. However, the underlying physicochemical mechanisms leading to the toxicity of AgNPs are still under debate. The present study revealed the different effects of three surface coatings (including lactate, polyvinylpyrrolidone, and sodium dodecylbenzene sulfonate, as AgNPs-L, AgNPs-P and AgNPs-S, respectively) on the acute toxicity of AgNPs to a model freshwater cladoceran Daphnia magna. Significant difference in mortality was observed among these three surface coatings of AgNPs, with the 48-h 50% lethal concentrations (48-h LC50s) of AgNPs-L, AgNPs-P and AgNPs-S being 28.7, 2.0 and 1.1 μg/L, respectively. In contrast, when the daphnids were exposed to soluble Ag released from AgNPs-L and AgNPs-P, the difference in the 48-h LC50s between the two surface coatings (1.1 μg/L and 0.57 μg/L, respectively) decreased significantly. These 48-h LC50s were comparable to that of AgNO₃ (0.88 μg/L), indicating that soluble Ag was the primarily cause of the observed toxicity of AgNPs. Indeed, the surface coatings influenced the dissolution of AgNPs into soluble Ag, resulting in the different toxicities of AgNP to the daphnids. Additionally, the 48-h bioaccumulation of AgNPs in daphnids was also dependent on the characteristics of the nanoparticles, such as particle size and surface coating. Our results point to the need to consider the effects of surface coating on the toxicity of AgNPs in environmental risk assessments. PMID:21591875

  15. Development of an NMR microprobe procedure for high-throughput environmental metabolomics of Daphnia magna.

    PubMed

    Nagato, Edward G; Lankadurai, Brian P; Soong, Ronald; Simpson, André J; Simpson, Myrna J

    2015-09-01

    Nuclear magnetic resonance (NMR) is the primary platform used in high-throughput environmental metabolomics studies because its non-selectivity is well suited for non-targeted approaches. However, standard NMR probes may limit the use of NMR-based metabolomics for tiny organisms because of the sample volumes required for routine metabolic profiling. Because of this, keystone ecological species, such as the water flea Daphnia magna, are not commonly studied because of the analytical challenges associated with NMR-based approaches. Here, the use of a 1.7-mm NMR microprobe in analyzing tissue extracts from D. magna is tested. Three different extraction procedures (D2O-based buffer, Bligh and Dyer, and acetonitrile : methanol : water) were compared in terms of the yields and breadth of polar metabolites. The D2O buffer extraction yielded the most metabolites and resulted in the best reproducibility. Varying amounts of D. magna dry mass were extracted to optimize metabolite isolation from D. magna tissues. A ratio of 1-1.5-mg dry mass to 40 µl of extraction solvent provided excellent signal-to-noise and spectral resolution using (1)H NMR. The metabolite profile of a single daphnid was also investigated (approximately 0.2 mg). However, the signal-to-noise of the (1)H NMR was considerably lower, and while feasible for select applications would likely not be appropriate for high-throughput NMR-based metabolomics. Two-dimensional NMR experiments on D. magna extracts were also performed using the 1.7-mm NMR probe to confirm (1)H NMR metabolite assignments. This study provides an NMR-based analytical framework for future metabolomics studies that use D. magna in ecological and ecotoxicity studies. PMID:25891518

  16. Acute toxicity of a mixture of copper and single-walled carbon nanotubes to Daphnia magna.

    PubMed

    Kim, Ki T; Klaine, Stephen J; Lin, Sijie; Ke, Pu C; Kim, Sang D

    2010-01-01

    Nanomaterials released into the environment will interact with many materials including other contaminants. This may influence bioavailability and fate of both the nanoparticles and the other contaminants. The present study examined the effect of a combination of soluble copper and surface-modified single-walled carbon nanotubes (SWNTs) on Daphnia magna. Lysophosphatidylcholine (LPC) was used to modify the surface of SWNTs, reducing the surface hydrophobicity of the tubes and thereby producing a stable aqueous nanoparticle suspension. The toxicity of the nanoparticle-copper (Cu) mixture was determined to be additive. The addition of nontoxic concentration of LPC-SWNTs enhanced the uptake and toxicity of copper. Greater amounts of Cu were shown to accumulate in D. magna upon addition of 0.5 and 1.0 mg/L LPC-SWNTs. PMID:20821426

  17. Effects of physiochemical properties of test media on nanoparticle toxicity to Daphnia magna Straus.

    PubMed

    Seo, Jaehwan; Kim, Soyoun; Choi, Seona; Kwon, Dongwook; Yoon, Tae-Hyun; Kim, Woo-Keun; Park, June-Woo; Jung, Jinho

    2014-09-01

    The physicochemical property of standard test media significantly influenced the aggregation and dissolution of Ag, CuO and ZnO nanoparticles (NPs) and the toxicity of the NPs to Daphnia magna. For all the NPs, the highest amount of metal ions was released from the ISO medium, whereas acute toxicity to D. magna was highest in the moderately hard water medium (EC50 = 4.94, 980, and 1,950 μg L(-1) for Ag, CuO, and ZnO, respectively). By comparing EC50 values based on the total and dissolved concentrations of NPs with those of metal salt solutions, we found that both particulate and dissolved fractions were likely responsible for the toxicity of Ag NPs, whereas the dissolved fraction mostly contributed to the toxicity of CuO and ZnO NPs. PMID:25063370

  18. Aquatic ecotoxicity of a pheromonal antagonist in Daphnia magna and Desmodesmus subspicatus.

    PubMed

    Rosa, Esmeralda; Barata, Carlos; Damásio, Joana; Bosch, Maria Pilar; Guerrero, Angel

    2006-09-12

    Evaluation of the ecotoxicological potential of (Z)-11-hexadecenyl trifluoromethyl ketone (Z11-16:TFMK), a new biorational agent with high prospective features to control the Mediterranean corn borer Sesamia nonagrioides in infested maize fields, in comparison to the parent pheromone compound (Z)-11-hexadecenyl acetate (Z11-16:Ac) is described. Acute and sublethal toxicity tests of both compounds against the cladoceran Daphnia magna and the chlorophyte Desmodesmus subspicatus were conducted, the endpoints being immobilisation and feeding inhibition for Daphnia and growth rate inhibition for Desmodesmus. In addition, effects on B esterases including cholinesterase and carboxylesterase activities in Daphnia were also assessed to evaluate the mode of action of both chemicals. Toxicities of both compounds were moderate with EC(50) values ranging from 3.11 to 103.74mgl(-1) in algae growth, from 0.07 to 1.20mgl(-1) in Daphnia survival, and from 0.10 to 0.53mgl(-1) in Daphnia feeding rate. In all cases Z11-16:TFMK was more toxic than the naturally occurring pheromone component. Serine esterase assays showed a strong inhibition of the carboxylesterase activities in Daphnia at concentrations with apparently no effects on survival or feeding, suggesting that inhibition of other key esterases may be the possible mechanism of toxicity of this compound. The results obtained have been related with some physico-chemical properties of the compounds, such as water solubility and octanol-water partition coefficient, suggesting that Z11-16:TFMK may affect aquatic organisms at lower concentrations than expected from non-polar narcosis. PMID:16899308

  19. An evaluation of biotic ligand models predicting acute copper toxicity to Daphnia magna in wastewater effluent.

    PubMed

    Constantino, Carlos; Scrimshaw, Mark; Comber, Sean; Churchley, John

    2011-04-01

    The toxicity of Cu to Daphnia magna was investigated in a series of 48-h immobilization assays in effluents from four wastewater treatment works. The assay results were compared with median effective concentration (EC50) forecasts produced by the HydroQual biotic ligand model (BLM), the refined D. magna BLM, and a modified BLM that was constructed by integrating the refined D. magna biotic ligand characterization with the Windermere humic aqueous model (WHAM) VI geochemical speciation model, which also accommodated additional effluent characteristics as model inputs. The results demonstrated that all the BLMs were capable of predicting toxicity by within a factor of two, and that the modified BLM produced the most accurate toxicity forecasts. The refined D. magna BLM offered the most robust assessment of toxicity in that it was not reliant on the inclusion of effluent characteristics or optimization of the dissolved organic carbon active fraction to produce forecasts that were accurate by within a factor of two. The results also suggested that the biotic ligand stability constant for Na may be a poor approximation of the mechanisms governing the influence of Na where concentrations exceed the range within which the biotic ligand stability constant value had been determined. These findings support the use of BLMs for the establishment of site-specific water quality standards in waters that contain a substantial amount of wastewater effluent, but reinforces the need for regulators to scrutinize the composition of models, their thermodynamic and biotic ligand parameters, and the limitations of those parameters. PMID:21184526

  20. The relative importance of water and food as cadmium sources to Daphnia magna Straus.

    PubMed

    Barata, Carlos; Markich, Scott J; Baird, Donald J; Soares, Amadeu M V M

    2002-12-01

    Knowledge of the transport pathways of metals into aquatic organisms is paramount in determining the metal's potential mechanism of toxicity. To determine the relative importance of water and food as cadmium (Cd) sources for the cladoceran Daphnia magna grazing on the algae Chlorella vulgaris, we measured cadmium accumulation and toxicity (feeding inhibition and survival) in three genetically different clones of D. magna subsequent to water, food, and water and food exposures. We found that Cd uptake from water and food was independent of source and additive in effect, with D. magna juveniles accumulating twice as much Cd from water than from food (algae). However, the efficiency with which Cd was assimilated by D. magna from its algal diet was much higher (10%) than from water (0.3%). Uptake and toxic responses were inversely related: tolerant clones accumulated more Cd. As a consequence, models based on uptake of metals from the combined routes of water and food may be reliable to predict metal dynamics in the field, but may fail to predict toxic effects since tolerance to metals is not necessarily linked to reduced total uptake of metals. PMID:12359386

  1. The relationship of total copper 48-h LC50s to Daphnia magna dry weight

    SciTech Connect

    Lazorchak, J.M. ); Waller, W.T. )

    1993-05-01

    A study was conducted with Daphnia magna to determine the effect of neonate weight loss or lack of weight gain on experimentally derived copper 48-h LC50s. Standard unfed tests as well as algal-fed (Selenastrum capricornutum) tests were used to look at weight loss and gain. No significant relationship was found between amount of weight loss and copper LC50s. However, dry weight of unfed and algal-fed control organisms could be used to predict total copper LC50s.

  2. Usefulness of the lipid index for biouptake studies with Daphnia magna

    SciTech Connect

    Dauble, D.D.; Klopfer, D.C.; Carlile, D.W.; Hanf, R.W.

    1984-04-01

    Adult Daphnia magna were starved and monitored for lipid content and brood production. Mean lipid index values declined for 72 hours to less than 50% of 24 hour values. Number of hatched young was inversely related to lipid storage and ovary production. Uptake kinetics of /sup 14/C-labelled quinoline was compared between two daphnid test groups with mean lipid scores of 5.4 and 2.8, respectively. Total /sup 14/C counts were significantly higher for the high lipid group at 8 hour. Our studies indicated that lipid reserves of daphnid test populations can be routinely monitored as an indicator of environmental stress.

  3. Food availability affects the strength of mutualistic host-microbiota interactions in Daphnia magna.

    PubMed

    Callens, Martijn; Macke, Emilie; Muylaert, Koenraad; Bossier, Peter; Lievens, Bart; Waud, Michael; Decaestecker, Ellen

    2016-04-01

    The symbiotic gut microbial community is generally known to have a strong impact on the fitness of its host. Nevertheless, it is less clear how the impact of symbiotic interactions on the hosts' fitness varies according to environmental circumstances such as changes in the diet. This study aims to get a better understanding of host-microbiota interactions under different levels of food availability. We conducted experiments with the invertebrate, experimental model organism Daphnia magna and compared growth, survival and reproduction of conventionalized symbiotic Daphnia with germ-free individuals given varying quantities of food. Our experiments revealed that the relative importance of the microbiota for the hosts' fitness varied according to dietary conditions. The presence of the microbiota had strong positive effects on Daphnia when food was sufficient or abundant, but had weaker effects under food limitation. Our results indicate that the microbiota can be a potentially important factor in determining host responses to changes in dietary conditions. Characterization of the host-associated microbiota further showed that Aeromonas sp. was the most prevalent taxon in the digestive tract of Daphnia. PMID:26405832

  4. Toxicity identification evaluation of anaerobically treated swine slurry: a comparison between Daphnia magna and Raphanus sativus.

    PubMed

    Villamar, Cristina A; Silva, Jeannette; Bay-Schmith, Enrique; Vidal, Gladys

    2014-01-01

    Anaerobic digestion does not efficiently reduce ionic compounds present in swine slurry, which could present a potential risk to aquatic ecosystems (surface runoff) and terrestrial ambient (irrigation). The objective of this study was to evaluate the ecotoxicological characteristics of anaerobically treated swine slurry using acute and chronic (epicotyl elongation) toxicity tests with Daphnia magna and Raphanus sativus and identification of suspected toxic compounds using the Toxicity Identification Evaluation (TIE) method. The evaluation was performed in three phases: physicochemical characterization of the slurry; acute/chronic toxicity testing with Daphnia magna and Raphanus sativus for each fraction of the TIE (cation and anion exchange columns, activated carbon, pH modification/aeration and EDTA) and identification of suspected toxic compounds. The anaerobically treated slurry contained concentrations of ammonium of 1,072 mg L(-1), chloride of 815 mg L(-1) and metals below 1 mg L(-1) with a D. magna acute toxicity (48h-LC50) of 5.3% and R. sativus acute toxicity (144h-LC50) of 48.1%. Epicotyl elongation of R. sativus was inhibited at concentrations above 25% (NOEC). The cation exchange reduced the toxicity and free ammonia by more than 90% for both bio-indicators. Moreover, this condition stimulated the epicotyl growth of R. sativus between 10% and 37%. In conclusion, the main compound suspected of causing acute toxicity in D. magna and acute/chronic toxicity in R. sativus is the ammonium. The findings suggest the need the ammonium treatment prior to the agricultural reuse of swine slurry given the high risk to contaminate the aquatic environment by runoff and toxicity of sensitive plants. PMID:25190563

  5. Effects of aqueous stable fullerene nanocrystal (nC60) on copper (trace necessary nutrient metal): Enhanced toxicity and accumulation of copper in Daphnia magna.

    PubMed

    Tao, Xianji; He, Yiliang; Fortner, John D; Chen, Yongsheng; Hughes, Joseph B

    2013-08-01

    Our focus herein is to evaluate the potential interaction between nC60 and copper, a trace necessary metal, in light of the impact on toxicity. The non-observable effects concentration (NOEC) of nC60 was confirmed as 100μgL(-1) before. When Daphnia magna was exposed to the mixture of copper solution and nC60 suspension (100μgL(-1)), LC50 of 48h was lower than that when they were exposed to copper solution alone. This result clearly showed the decrease in NOEC of copper at the presence of nC60. Cu(2+)-ATPase activity was enhanced at the presence of nC60, indicating that copper transport involved with the uptake, distribution and depuration in body was increased. We further conducted experiments on accumulation of copper in D. magna. The observed equilibrium copper concentration in D. magna in the mixture of 100μgL(-1) nC60 and 1μgL(-1) copper solution reached 131μg (kg wet weight)(-1), which was more than twice that in copper solution only: 60μg (kg wet weight)(-1). This result demonstrated that the accumulation of copper in D. magna was significantly enhanced at the presence of even low nC60 concentration. Experiments also showed that copper was quickly adsorbed onto nC60. The absorption of copper onto D. magna was statistically correlated to the absorption of nC60 onto D. magna; this might be caused by nC60 facilitating the transfer of copper into D. magna. The absorption and desorption of copper to nC60 (pH=5.0) reached equilibrium quickly, which may be involved with the co-bioaccumulation and decrease in NOEC of Cu(2+) and nC60. PMID:23755985

  6. Biological Surface Coating and Molting Inhibition as Mechanisms of TiO2 Nanoparticle Toxicity in Daphnia magna

    PubMed Central

    Dabrunz, André; Duester, Lars; Prasse, Carsten; Seitz, Frank; Rosenfeldt, Ricki; Schilde, Carsten; Schaumann, Gabriele E.; Schulz, Ralf

    2011-01-01

    The production and use of nanoparticles (NP) has steadily increased within the last decade; however, knowledge about risks of NP to human health and ecosystems is still scarce. Common knowledge concerning NP effects on freshwater organisms is largely limited to standard short-term (≤48 h) toxicity tests, which lack both NP fate characterization and an understanding of the mechanisms underlying toxicity. Employing slightly longer exposure times (72 to 96 h), we found that suspensions of nanosized (∼100 nm initial mean diameter) titanium dioxide (nTiO2) led to toxicity in Daphnia magna at nominal concentrations of 3.8 (72-h EC50) and 0.73 mg/L (96-h EC50). However, nTiO2 disappeared quickly from the ISO-medium water phase, resulting in toxicity levels as low as 0.24 mg/L (96-h EC50) based on measured concentrations. Moreover, we showed that nTiO2 (∼100 nm) is significantly more toxic than non-nanosized TiO2 (∼200 nm) prepared from the same stock suspension. Most importantly, we hypothesized a mechanistic chain of events for nTiO2 toxicity in D. magna that involves the coating of the organism surface with nTiO2 combined with a molting disruption. Neonate D. magna (≤6 h) exposed to 2 mg/L nTiO2 exhibited a “biological surface coating” that disappeared within 36 h, during which the first molting was successfully managed by 100% of the exposed organisms. Continued exposure up to 96 h led to a renewed formation of the surface coating and significantly reduced the molting rate to 10%, resulting in 90% mortality. Because coating of aquatic organisms by manmade NP might be ubiquitous in nature, this form of physical NP toxicity might result in widespread negative impacts on environmental health. PMID:21647422

  7. Assessment of chronic effects of tebuconazole on survival, reproduction and growth of Daphnia magna after different exposure times.

    PubMed

    Sancho, E; Villarroel, M J; Ferrando, M D

    2016-02-01

    The effect of the fungicide tebuconazole (0.41, 0.52, 0.71 and 1.14mg/L) on survival, reproduction and growth of Daphnia magna organisms was monitored using 14 and 21 days exposure tests. A third experiment was performed by exposing D. magna to the fungicide for 14 days followed by 7 days of recovery (14+7). In order to test fungicide effects on D. magna, parameters as survival, mean whole body length, mean total number of neonates per female, mean number of broods per female, mean brood size per female, time to first brood/reproduction and intrinsic rate of natural increase (r) were used. Reproduction was seriously affected by tebuconazole. All tebuconazole concentrations tested affected the number of broods per female and day to first brood. At 14-days test, number of neonates per female and body size decreased by concentrations of tebuconazole higher than 0.52mg/L, whereas at 21-days test both parameters were affected at all the concentrations tested. Survival of the daphnids after 14 days fungicide exposure did not exhibited differences among experimental and control groups. In this experiment r value was reduced (in a 22%) when animals were exposed to concentrations of 0.71mg/L and 1.14mg/L. Survival of daphnids exposed during 21 days to 1.14mg/L declined, and the intrinsic rate of natural increase (r) decreased in a 30 % for tebuconazole concentrations higher than 0.41mg/L. Longevity of daphnids pre-exposed to tebuconazole for 14 days and 7 days in clean water did not show differences from control values and all of them survived the 21 days of the test. However, after 7 days in fungicide free medium animals were unable to restore control values for reproductive parameters and length. The maximum acceptable toxicant concentration (MATC) was calculated using the r values as parameter of evaluation. MATC estimations were 0.61mg/L and 0.46mg/L for 14 and 21 days, respectively. Results showed that the number of neonates per female was the highest sensitive

  8. Laboratory investigation into the development of resistance of Daphnia magna to the herbicide molinate.

    PubMed

    Sánchez, M; Andreu-Moliner, E; Ferrando, M D

    2004-11-01

    Daphnia magna (F0 generation) was exposed to different sublethal molinate concentrations (0, 3.77, 4.71, 6.28, 9.42, and 18.85 mg/L) during 21 days. Chronic toxicity tests, using the same herbicide concentrations, were also carried out during 21 days using neonates of F1 first brood (F1-1st) and F1 third brood (F1-3rd) offspring generations from the parentals (F0) preexposed to the herbicide. Finally, offspring (from F1-1st and F1-3rd broods) were transferred to herbicide-free medium during a 21-day recovery period. The alga Nannochloris oculata (5 x 10(5) cells/mL) was used as food in all the experiments. The effect of molinate on survival, reproduction, and growth was monitored for the selected daphnid generations. The parameters used to evaluate herbicide effect on reproduction were mean total young per female, mean brood size, time to first reproduction, mean number broods per female, and intrinsic rate of natural increase (r). Survival and growth (body length) were also determined after 21 days of exposure to molinate. Reproduction was significantly reduced when molinate concentration was increased in the medium. This effect was higher in the parental (F0) daphnids than in the F1-1st and F1-3rd offspring. In the recovery study, reproduction was still reduced in F1 generation daphnids (1st and 3rd), but only in those animals from parentals exposed to the highest molinate concentrations. The decreased with increasing concentrations of molinate in daphnids from the parental generation (F0). Significant differences were also found in daphnids from the F1 generation (exposure). The growth of the exposed organisms (F0 and F1) decreased, although the greatest decrease was found in the parental animals (F0) (25%) exposed to 9.42 mg/L molinate. F1 daphnids (1st and 3rd broods) from the recovery period did not show any significant difference in their growth after 21 days of study. Finally, survival was not affected after exposure to the selected molinate concentrations

  9. Environmental labeling of car tires--toxicity to Daphnia magna can be used as a screening method.

    PubMed

    Wik, Anna; Dave, Göran

    2005-02-01

    Car tires contain several water-soluble compounds that can leach into water and have toxic effects on aquatic organisms. Due to tire wear, 10,000 tonnes of rubber particles end up along the Swedish roads every year. This leads to a diffuse input of emissions of several compounds. Emissions of polyaromatic hydrocarbons (PAHs) are of particular concern. PAHs are ingredients of the high aromatic oil (HA oil) that is used in the rubber as a softener and as a filler. The exclusion of HA oils from car tires has started, and an environmental labeling of tires could make HA oils obsolete. The toxicity to Daphnia magna from 12 randomly selected car tires was tested in this study. Rubber from the tread of the tires was grated into small pieces, to simulate material from tire wear, and the rubber was equilibrated with dilution water for 72 h before addition of test organisms. The 24-h EC50s of the rubber pieces ranged from 0.29 to 32 gl-1, and the 48-h EC50s ranged from 0.0625 to 2.41 gl-1. Summer tires were more toxic than winter tires. After the 48-h exposure, the daphnids were exposed to UV-light for 2 h, to determine if the tires contained compounds that were phototoxic. After UV-activation the EC50s ranged from 0.0625 to 0.38 gl-1. Four of the 12 tires had a very distinct photoactivation, with a toxicity increase of >10 times. This study has shown that the used method for toxicity testing with Daphnia magna according to ISO 6341 could be used as a basis for environmental labeling of car tires. PMID:15620758

  10. Species interactions and chemical stress: combined effects of intraspecific and interspecific interactions and pyrene on Daphnia magna population dynamics.

    PubMed

    Viaene, Karel P J; De Laender, Frederik; Rico, Andreu; Van den Brink, Paul J; Di Guardo, Antonio; Morselli, Melissa; Janssen, Colin R

    2015-08-01

    Species interactions are often suggested as an important factor when assessing the effects of chemicals on higher levels of biological organization. Nevertheless, the contribution of intraspecific and interspecific interactions to chemical effects on populations is often overlooked. In the present study, Daphnia magna populations were initiated with different levels of intraspecific competition, interspecific competition, and predation and exposed to pyrene pulses. Generalized linear models were used to test which of these factors significantly explained population size and structure at different time points. Pyrene had a negative effect on total population densities, with effects being more pronounced on smaller D. magna individuals. Among all species interactions tested, predation had the largest negative effect on population densities. Predation and high initial intraspecific competition were shown to interact antagonistically with pyrene exposure. This was attributed to differences in population structure before pyrene exposure and pyrene-induced reductions in predation pressure by Chaoborus sp. larvae. The present study provides empirical evidence that species interactions within and between populations can alter the response of aquatic populations to chemical exposure. Therefore, such interactions are important factors to be considered in ecological risk assessments. PMID:25772479

  11. Chronic toxicity of di-n-butyl and di-n-octyl phthalate to Daphnia magna and the fathead minnow

    SciTech Connect

    McCarthy, J.F.; Whitmore, D.K.

    1985-01-01

    The toxicities of di-n-butyl phthalate (DBP) and di-n-octyl phthalate (DOP) were assessed by measuring the effect of exposure to these compounds on the fecundity of Daphnia magna and on the hatching and survival of the early life stages of the fathead minnow Pimephales promelas. For D. magna, exposure to 1.8 mg/L DBP or 1.0 mg/L DOP caused a significant reduction in reproduction. Doses of 0.56 mg/L DBP or 0.32 mg/L DOP had no significant effect in decreasing reproduction. Survival of fathead minnow embryos was decreased by exposure to 1.8 mg/L DBP; none of the embryos exposed to this dose hatched successfully. Hatching and larval survival were affected by exposure to 1.0 mg/L DBP, but not to 0.56 mg/L. Exposure to DOP did not affect survival of either early embryos or larvae of the fathead minnow at doses up to 10 mg/L (the highest dose tested). Hatching of the embryos was significantly decreased at 10 mg/L, but not at 3.2 mg/L DOP. 26 references, 4 figures, 11 tables.

  12. Influence of polychlorinated aromatic compounds on the biotransformation and toxicity of organophosphorus pesticides (OP) to the Daphnia magna

    SciTech Connect

    Tonkopii, V.; Zagrebin, A.; Sherstneva, L.

    1995-12-31

    The effect of different polychlorinated aromatics (DDT, Aroclor 1254, certain polychlorinated biphenyls and dibenzofurans) on the toxicity of OP (DDVP paraoxon, malaoxon) to Daphnia magna was studied. Pretreatment of daphnids with chlorinated compounds during 72 hours in nontoxic concentrations (1/5--1/20 CL{sub 50}) has been shown to reduce the toxicity of OP for hydrobionts. For study of influence of chlorinated compounds on biotransformation of OP the activity of enzymes which are hydrolyzing the OP was investigated in Daphnia`s homogenates or microsomes. The activity of carboxylesterase (tributyrinase, aliesterase) and arylesterase (phosphorylphosphatase) with usage as substrates accordingly {alpha}-naphthylacetate and paraoxon was measured. Besides that the activity of cholinesterase with application of propionylthiocholine as substrate was determined. After polychlorinated aromatic compounds treatment of daphnids activities of both aryl-and carboxylesterase increased markedly. It decreased the inhibition of Daphnia`s cholinesterase caused by incubation with OP in concentrations 0.5--1.0 CL{sub 50}. Thus the induction by chlorinate aromatics of OP metabolizing enzymes seems to play the important role in reduction of OP toxicity to Daphnia magna. Perhaps the aryl- and carboxylesterase of Daphnia can be used as biomarkers of pollution by polychlorinated aromatics in water.

  13. The developmental toxicity of 1-methyl-3-octylimidazolium bromide on Daphnia magna.

    PubMed

    Luo, Yan-Rui; Li, Xiao-Yu; Chen, Xiao-Xiao; Zhang, Bang-Jun; Sun, Zhen-Jun; Wang, Jian-Ji

    2008-12-01

    The developmental toxicity of 1-methyl-3-octylimidazolium bromide ([C(8)mim]Br) on Daphnia magna was investigated. The 24 and 48 h LC(50) values for [C(8)mim]Br in D. magna were 1.99 and 0.95 mg/L, respectively. A series of multigenerational toxicity tests were then used to explore [C(8)mim]Br effects in D. magna. [C(8)mim]Br significantly inhibited the body lengths of the F0 and F1 1st generations. After 21 days of exposure, [C(8)mim]Br lowered the reproductive ability of the F0 and F1 1st generations. In F1 3rd generation, 21 days of [C(8)mim]Br exposure prolonged the time to bear the first egg and the time to the first brood compared with the control, but the number of first-brood offspring and the number of broods produced by these animals were reduced. After the recovery period all the reproductive parameters returned to normal in F1 1st generation except for the number of broods. The dead neonates increased with prolonged exposure and increasing concentrations, and the dead neonates of the F1 3rd generation went far beyond that of the F1 1st and F0 generations. The intrinsic rate of natural increase (r) values of the three D. magna generations significantly decreased after exposure to higher concentrations of [C(8)mim]Br compared with control groups. Collectively, these results suggest that [C(8)mim]Br exerts a toxic effect on the development of D. magna. This study also highlights the importance of systematically evaluating the potential effects of aquatic ecosystems of ionic liquids that may be released into bodies of water. PMID:18442076

  14. Surface binding of contaminants by algae: Consequences for lethal toxicity and feeding to Daphnia magna straus

    SciTech Connect

    Taylor, G. |; Baird, D.J.; Soares, A.M.V.M.

    1998-03-01

    Freshwater algae, as with all suspended particulate matter in the water column, exhibit a net negative charge resulting in an affinity for positively charged species, such as toxic metal cations, which will readily adsorb to algal cell surfaces. In this study, the adsorption of a representative toxic metal cadmium cation (Cd{sup 2+}) to a freshwater algal species, Chlorella vulgaris, was investigated using environmentally realistic concentrations of both. A further study of the effects of this particulate adsorption of Cd{sup 2+} on lethal toxicity and feeding in Daphnia magna was conducted. Two apparently contrasting effects were observed. For the D. magna feeding study, cell ingestion was inhibited, leading to reduced growth and reproduction. Experiments comparing the effect of algal-bound cadmium and dissolved forms of cadmium demonstrate that this inhibition is almost entirely due to the surface-bound fraction of ions. However, at concentrations of dissolved cadmium that are lethal to Daphnia, algal cells were found to reduce toxicity. Such findings indicate the importance of food ration in laboratory-based toxicity tests as well as the difficulty in predicting the environmental fate and effect of contaminants using such tests.

  15. Multigenerational effect of perfluorooctane sulfonate (PFOS) on the individual fitness and population growth of Daphnia magna.

    PubMed

    Jeong, Tae-Yong; Yuk, Min-Su; Jeon, Junho; Kim, Sang Don

    2016-11-01

    We investigated the multigenerational effect of PFOS to individual fitness (e.g., body weight, acetylcholinesterase and glutathione S-transferase) and population growth (e.g., offspring number and time to first brood) of Daphnia magna during continuous and discontinuous exposures. The intrinsic rate of population growth was also calculated. In the continuous exposure, population growth-related adverse effects were detected during all test periods, and the adverse effect tended to be weaker in later generations. On the other hand, individual fitness-related adverse effects were observed from F1 not in F0 and deteriorated as the generation number increased. These results imply that individual fitness worsens although the population growth is restored in later generations. Upon discontinuous exposure, a few but significant adverse effects were observed during the non-exposure period and highest effects were detected during the re-exposure period. This encourages the study of different exposure scenarios, which may result in unexpected and higher PFOS toxicity. Consequently, this study confirms adverse effects of PFOS to Daphnia magna in multigenerational period and supports reasons for studies linking individual fitness changes to population dynamics and covering diverse exposure scenarios to evaluate the risk of PFOS in a water environment. PMID:27396314

  16. Effects from Filtration, Capping Agents, and Presence/Absence of Food on the Toxicity of Silver Nanoparticles to Daphnia Magna

    EPA Science Inventory

    Relatively little is known regarding the behavior and toxicity of nanoparticles in the environment. The objectives of the work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of ...

  17. Effects of nanoparticles of TiO2 on food depletion and life-history responses of Daphnia magna.

    PubMed

    Campos, Bruno; Rivetti, Claudia; Rosenkranz, Philipp; Navas, José María; Barata, Carlos

    2013-04-15

    The extent to which different forms of nanoparticles of titanium dioxide (nano-TiO2) aggregated with microalgae, decreased food levels and hence impaired growth, reproduction and fitness of Daphnia magna individuals were studied. Treatments included three different types of nano-TiO2 differing in their coating or crystalline structure but of similar primary size (20 nm) plus a micron-sized bulk material, two exposure levels (1, 10mg/l) and two food ration levels of the microalgae Chlorella vulgaris that included a non limiting (1.5 μgC/ml) and a limiting one (0.3 μgC/ml). Effects were assessed using standardized chronic tests and assays that maximized food depletion in the water column under semi-static and re-suspension conditions. Results indicated that the high ion levels in culture medium lead to the aggregation of nanoparticles followed by particle destabilization. Nanoparticle aggregates interacted with the algae cells, forming clusters. Large TiO2-algae agglomerates settled readily dramatically depleting the concentration of available food for D. magna. At limiting food rations food depletion by nanoparticle aggregation had dramatic effects on reproduction and fitness of exposed D. magna at 1mg/l irrespectively of the particle form. At high food rations effects were only observed for one of the nano-TiO2, P-25, at high exposure levels (10 mg/l) under both semi-static and particle re-suspension conditions, which suggest that P-25 effects were mediated by clogging the gut and hence diminishing food acquisition. These results indicate that nano-TiO2 may affect the transfer of energy throughout the planktonic aquatic food webs increasing the settlement of edible particles from the water column. PMID:23416410

  18. Gene transcription in Daphnia magna: effects of acute exposure to a carbamate insecticide and an acetanilide herbicide.

    PubMed

    Pereira, Joana Luísa; Hill, Christopher J; Sibly, Richard M; Bolshakov, Viacheslav N; Gonçalves, Fernando; Heckmann, Lars-Henrik; Callaghan, Amanda

    2010-05-01

    Daphnia magna is a key invertebrate in the freshwater environment and is used widely as a model in ecotoxicological measurements and risk assessment. Understanding the genomic responses of D. magna to chemical challenges will be of value to regulatory authorities worldwide. Here we exposed D. magna to the insecticide methomyl and the herbicide propanil to compare phenotypic effects with changes in mRNA expression levels. Both pesticides are found in drainage ditches and surface water bodies standing adjacent to crops. Methomyl, a carbamate insecticide widely used in agriculture, inhibits acetylcholinesterase, a key enzyme in nerve transmission. Propanil, an acetanilide herbicide, is used to control grass and broad-leaf weeds. The phenotypic effects of single doses of each chemical were evaluated using a standard immobilisation assay. Immobilisation was linked to global mRNA expression levels using the previously estimated 48h-EC(1)s, followed by hybridization to a cDNA microarray with more than 13,000 redundant cDNA clones representing >5000 unique genes. Following exposure to methomyl and propanil, differential expression was found for 624 and 551 cDNAs, respectively (one-way ANOVA with Bonferroni correction, P

  19. β-N-methylamino-L-alanine (BMAA) uptake by the animal model, Daphnia magna and subsequent oxidative stress.

    PubMed

    Esterhuizen-Londt, Maranda; Wiegand, Claudia; Downing, Tim G

    2015-06-15

    β-N-methylamino-l-alanine (BMAA), produced by cyanobacteria, is a neurotoxin implicated in Amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC). BMAA concentrations in cyanobacteria are lower than those thought to be necessary to result in neurological damage thus bioaccumulation or biomagnification is required to achieve concentrations able to cause neurodegeneration. Many cyanobacteria produce BMAA and uptake routes into the food web require examination. In this study we investigate the uptake of BMAA by adult phytoplanktivorus Daphnia magna via exposure to dissolved pure BMAA and BMAA containing cyanobacteria, as well as the subsequent oxidative stress response in the daphnia. Free BMAA and protein-associated BMAA were quantified by LC-MS/MS. Dissolved BMAA was taken up and was found as free BMAA in D. magna. No protein-associated BMAA was detected in D. magna after a 24-h exposure period. No BMAA was detectable in D. magna after exposure to BMAA containing cyanobacteria. BMAA inhibited the oxidative stress defence and biotransformation enzymes within 24-h exposure in the tested Daphnia and could therefore impair the oxidant status and the capability of detoxifying other substances in D. magna. PMID:25841344

  20. Aminomethylphosphonic acid has low chronic toxicity to Daphnia magna and Pimephales promelas.

    PubMed

    Levine, Steven L; von Mérey, Georg; Minderhout, Tui; Manson, Philip; Sutton, Peter

    2015-06-01

    Aminomethylphosphonic acid (AMPA) is the simplest member of a class of compounds known as aminomethylenephosphonates and the only environmental metabolite measured in significant amounts during the degradation of the herbicide glyphosate in soil. However, there are additional sources of AMPA in the environment, originating from organic phosphonates which are used in water treatment to inhibit scale formation and corrosion. Like glyphosate, AMPA has low acute toxicity to aquatic animals, and the no-observed-adverse effect concentration (NOAEC) obtained from a fish full-life cycle study for glyphosate was determined to be 26 mg/L. However, the chronic toxicity of AMPA to aquatic animals has not been evaluated before. The purpose of the present study was to assess the potential for chronic toxicity of AMPA to fathead minnow (Pimephales promelas) and Daphnia magna. Chronic toxicity to P. promelas was evaluated in a fish early-life stage study. The primary endpoints were larval survival, growth, and development. The NOAEC for P. promelas was determined to be 12 mg/L, the highest concentration tested. The chronic toxicity to D. magna was evaluated in a Daphnia reproduction test. The primary endpoints were survival, growth, and reproduction. The no-observed-effect concentration for D. magna was determined to be 15 mg/L. Conservatively predicted environmental surface water concentrations for AMPA from typical foliar agricultural application rates and values from surface water monitoring programs are 100 to 1000 times less than the NOAEC values from both studies. Consequently, there is a large and highly protective margin of safety between realistic environmental exposures to AMPA and chronic toxicity to aquatic vertebrates and invertebrates. PMID:25690938

  1. What causes the difference in synergistic potentials of propiconazole and prochloraz toward pyrethroids in Daphnia magna?

    PubMed

    Dalhoff, Kristoffer; Gottardi, Michele; Kretschmann, Andreas; Cedergreen, Nina

    2016-03-01

    Azole fungicides (imidazoles and triazoles) are known to function synergistically with several compounds, especially with pyrethroid insecticides, most likely by inhibiting cytochrome P450. Different azole fungicides have been shown to differ in their synergistic potentials usually with the imidazoles being stronger synergists than the triazoles. This study investigated whether the toxicokinetic and toxicodynamic (TKTD) properties of the imidazole prochloraz and triazole propiconazole can explain their different synergistic potential toward the freshwater macroinvertebrate Daphnia magna. Pulse exposure to external concentrations of propiconazole (1.4μM) and prochloraz (1.7μM) for 18h resulted in internal concentrations of 22.7 and 53.5μmolkg(-1)w.w. for propiconazole and prochloraz, respectively. This 2-fold difference in bioaccumulation corresponded very well with the observed 2.7-fold lower external EC50-estimate (7 days) for prochloraz compared to propiconazole. The estimated IC50 for the in vivo inhibition of cytochrome P450 (ECOD) activity, however, measured as transformation of 7-ethoxycoumarin into 7-hydroxycoumarin, was almost 500-fold higher for prochloraz (IC50: 0.011±0.002μM) compared to propiconazole (IC50: 4.9±0.06μM). When indirectly measuring the binding strength of the two azoles, daphnids exposed to propiconazole recovered roughly 80% of their ECOD activity compared to the control shortly after being moved to azole-free medium, indicating that propiconazole causes reversible inhibition of cytochrome P450. In contrast, the ECOD-activity remained inhibited in the prochloraz-exposed daphnids for 12h following transfer to azole-free medium, which correlated with elimination of the measured internal prochloraz concentration (DT95≈13h). These results indicate that lethal toxicity of the azole fungicides is mainly driven by toxicokinetics through their hydrophobicities resulting in different internal concentrations. Their synergistic potential

  2. The use of cohorts and populations in chronic toxicity studies with Daphnia magna: a cadmium example.

    PubMed

    van Leeuwen, C J; Luttmer, W J; Griffioen, P S

    1985-02-01

    Two semistatic life table experiments with Daphnia magna were carried out on reconstituted and Lake IJssel water. The "nontoxic concentrations" for cadmium with respect to the intrinsic rate of natural increase, derived from age-specific survival and fecundity were 1 and 3.2 micrograms/liter, respectively. Body length appeared to be a sensitive parameter. A third intermittent-flow experiment was started with small, exponentially growing populations. These populations had a stable age distribution, were composed of cohorts of different ages and showed an almost perfect logistic growth. Cadmium was shown to reduce the upper numerical limit (carrying capacity) for D. magna and was inversely related to this parameter: log Y = 2.85 -0.20 log [Cd]; r = -0.99. A "nontoxic concentration" could not be established. Based on the "background" concentration of cadmium, a freshwater quality criterion of 0.1 microgram/liter is proposed. The results are used to discuss several shortcomings of the current methods. Finally it is stated that the introduction of the concepts of population dynamics in reproduction tests with D. magna is a realistic step towards ecotoxicology. PMID:3987588

  3. Inactivation mechanism of chlorination in Escherichia coli internalized in Limnoithona sinensis and Daphnia magna.

    PubMed

    Lin, Tao; Chen, Wei; Cai, Bo

    2016-02-01

    Zooplankton may harbor microorganisms in the aquatic environment, thus protecting them from disinfection during drinking water treatment. However, few studies have evaluated the protective effect of internalization by zooplankton against bacterial disinfection. In this study, we investigated the role of zooplankton (Limnoithona sinensis and Daphnia magna) as a refuge for ingested bacteria against inactivation by chlorination. Only 30% of chlorine reached the internalized bacteria inside the digestive tract of zooplankton. However, this was sufficient to achieve 1.4 log inactivation of internalized Escherichia coli in L. sinensis and 1.2 log inactivation in D. magna at Ct values of 80 mg min/L. Inactivation of internalized bacteria was achieved through the active transfer of free chlorine in the bulk water into the zooplankton digestive tract during grazing activity. D. magna was more sensitive to hypochlorous acid than L. sinensis, and its grazing behavior was inhibited during the inactivation experiment. PMID:26624518

  4. Combined effects of water quality parameters on mixture toxicity of copper and chromium toward Daphnia magna.

    PubMed

    Jo, Hun-Je; Son, Jino; Cho, Kijong; Jung, Jinho

    2010-11-01

    In this study, a central composite design (CCD) was employed to evaluate the combined effects of pH, hardness and dissolved organic carbon (DOC) on the toxicity of a mixture of Cu(II) and Cr(VI) toward Daphnia magna. Overall, the results showed that increases in pH, hardness and DOC concentration led to decreased mixture toxicity of Cu(II) and Cr(VI) by reducing the concentrations of toxic species such as Cu(2+) and HCrO(4)(-). In addition, empirical models for the prediction of 24-h and 48-h mortalities of D. magna were developed and validated by using three different sources of dissolved organic matter (DOM). Because the DOMs had different Cu(II)-binding capacities, the empirical models were revised using the ligand concentration of DOMs instead of the DOC concentration; however, the prediction capability of these models did not differ significantly. These results suggest that it is not likely that the chemical property of DOM is important for prediction of the mixture toxicity of Cu(II) and Cr(VI) toward D. magna when the ligand concentration of DOMs greatly exceed the Cu(II) concentration. PMID:20875667

  5. Chronic toxicity of silver nitrate to Ceriodaphnia dubia and Daphnia magna, and potential mitigating factors.

    PubMed

    Naddy, Rami B; Gorsuch, Joseph W; Rehner, Anita B; McNerney, Gina R; Bell, Russell A; Kramer, James R

    2007-08-15

    We investigated the chronic toxicity of Ag, as silver nitrate, using two freshwater aquatic cladoceran species, Ceriodaphnia dubia and Daphnia magna, to generate data for the development of a chronic ambient water quality criterion for Ag. Preliminary studies with C. dubia showed variable results which were related to the equilibration time between food and silver. Follow-up testing was conducted using a 3h equilibration time, which stabilized dissolved Ag concentrations and the toxicity of Ag(+). Results with C. dubia conducted individually (1 per cup, n=10) and in mass (30 per chamber, n=2) gave similar results once similar standardized equilibration times were used. The maximum acceptable toxicant concentration (MATC) of Ag to C. dubia and D. magna was 9.61 and 3.00microg dissolved Ag/L, respectively. The chronic toxicity of Ag(+) to C. dubia was also evaluated in the presence of: (1) dissolved organic carbon (DOC) and (2) sulfide. The addition of DOC (0.4mg/L) resulted in a approximately 50% decrease in toxicity while the addition of sulfide (75.4nM) deceased toxicity by 42%. Whole-body Ag concentration in D. magna was positively correlated with increased levels of Ag exposure, however; we observed a non-statistical decrease in whole-body Na levels, an estimator of sodium homeostasis. PMID:17658626

  6. Cohorts and populations in chronic toxicity studies with Daphnia magna: a cadmium example

    SciTech Connect

    van Leeuwen, C.J.; Luttmer, W.J.; Griffioen, P.S.

    1985-02-01

    Two semistatic life table experiments with Daphnia magna were carried out on reconstituted and Lake Ijssel water. The nontoxic concentrations for cadmium with respect to the intrinsic rate of natural increase, derived from age-specific survival and fecundity were 1 and 3.2 micrograms/liter, respectively. Body length appeared to be a sensitive parameter. A third intermittent-flow experiment was started with small, exponentially growing populations. These populations had a stable age distribution, were composed of cohorts of different ages and showed an almost perfect logistic growth. Cadmium was shown to reduce the upper numerical limit (carrying capacity) for D. magna and was inversely related to this parameter: log Y = 2.85 -0.20 log (Cd); r = -0.99. A nontoxic concentration could not be established. Based on the background concentration of cadmium, a freshwater quality criterion of 0.1 microgram/liter is proposed. The results are used to discuss several shortcomings of the current methods. Finally it is stated that the introduction of the concepts of population dynamics in reproduction tests with D. magna is a realistic step towards ecotoxicology.

  7. Toxicity Thresholds for Diclofenac, Acetaminophen and Ibuprofen in the Water Flea Daphnia magna.

    PubMed

    Du, Juan; Mei, Cheng-Fang; Ying, Guang-Guo; Xu, Mei-Ying

    2016-07-01

    Non-steroid anti-inflammatory drugs (NSAIDs) have been frequently detected in aquatic ecosystem and posed a huge risk to non-target organisms. The aim of this study was to evaluate the toxic effects of three typical NSAIDs, diclofenac (DFC), acetaminophen (APAP) and ibuprofen (IBP), toward the water flea Daphnia magna. All three NSAIDs showed remarkable time-dependent and concentration-dependent effects on D. magna, with DFC the highest and APAP the lowest toxic. Survival, growth and reproduction data of D. magna from all bioassays were used to determine the LC10 and LC50 (10 % lethal and median lethal concentrations) values of NSAIDs, as well as the EC10 and EC50 (10 % effect and median effect concentrations) values. Concentrations for the lethal and sublethal toxicity endpoints were mainly in the low ppm-range, of which reproduction was the most sensitive one, indicating that non-target organisms might be adversely affected by relevant ambient low-level concentrations of NSAIDs after long-time exposures. PMID:27098253

  8. Evaluation of a high-hardness COMBO medium and frozen algae for Daphnia magna.

    PubMed

    Baer, K N; Goulden, C E

    1998-03-01

    A new high-hardness (H-H) COMBO medium for long-term culturing and bioassay testing of Daphnia magna was evaluated in 21-day survival, growth, and reproduction studies. The COMBO medium originally designed for softwater daphnid species (i.e., D. pulicaria) was modified for the hardwater species D. magna. This medium also allowed continuous culturing of a green algal food source for daphnids, Ankistrodesmus falcatus. After 12 generations of culturing in H-H COMBO medium, the mean fecundity was 128 +/- 12 (coefficient of variation = 9.4%). No significant observations of dead young, aborted eggs, or reduced antennas were made during the 6 months of continuous culturing. The no-observable-effect concentration (NOEC) for a reference toxicant standard, 3,4-dichloroaniline (3,4-DCA), was 8.3 micrograms/liter, which is similar to published values. These studies demonstrate that H-H COMBO is an acceptable medium for use for culturing and bioassay testing with D. magna. Additional experiments using frozen aliquots of A. falcatus were conducted. Although mean fecundity (64 +/- 7) and adult length were significantly decreased from the values for daphnids fed fresh algae, the NOEC for 3,4-DCA was > 25 micrograms/liter. The use of this alternative food source in bioassay testing appears promising, but further optimization of feeding rates is warranted. PMID:9570911

  9. Hard X-ray nanoprobe investigations of the subtissue metal distributions within Daphnia magna.

    PubMed

    De Samber, B; De Schamphelaere, K A C; Janssen, C R; Vekemans, B; De Rycke, R; Martinez-Criado, G; Tucoulou, R; Cloetens, P; Vincze, L

    2013-07-01

    The unique potential of nanoscale elemental imaging of major/minor and trace-level elemental distributions within thin biological tissue sections of the ecotoxicological model organism Daphnia magna is demonstrated by synchrotron radiation nano-X-ray fluorescence (nano-XRF). The applied highly specialized sample preparation method, coupled with the high spatial resolution (∼180 nm) and high X-ray photon flux (6 × 10(11) photons/s) available at the European Synchrotron Radiation Facility (ESRF) ID22NI beamline proved to be critical for the high-quality visualization of (trace-)metal distributions on the submicron level within the target structures of interest. These include the branchial sacs on the thoracic appendages (epipodites) of D. magna, which are osmoregulatory regions where ion exchange occurs. For the main element of interest (Zn), detection limits of 0.7 ppm (3 ag) was reached in fast-scanning mode using an acquisition time of 0.3 s/pixel. As demonstrated, synchrotron radiation nano-XRF revealed the elemental distributions of Ca, Fe, and Zn within this osmoregulatory region on the submicron scale, aiding the exploration of possible detoxification mechanisms of Zn within D. magna at the subtissue level. PMID:23681201

  10. Effects of the artificial sweetener sucralose on Daphnia magna and Americamysis bahia survival, growth and reproduction.

    PubMed

    Huggett, D B; Stoddard, K I

    2011-10-01

    The artificial sweetener sucralose has been detected in municipal wastewater effluent and surface waters at concentrations ranging from ng/L to low μg/L. Few chronic ecotoxicological data are available in the peer reviewed literature with respect to sucralose. To address this data gap, 21 d Daphnia magna and 28 d Americamysis bahia (mysid shrimp) studies were conducted to assess the effects of sucralose on the survival, growth and reproduction of these organisms. Concentrations ⩽1800mg/L resulted in no statistically significant reduction in D. magna survival or reproduction. Survival, growth and reproduction of mysid shrimp were unaffected by ⩽93mg/L sucralose. The no observable effect concentration (NOEC) and lowest observable effect concentration (LOEC) for the D. magna study were 1800 and >1800mg/L, respectively. The NOEC and LOEC for the mysid study were 93 and >93mg/L, respectively. Collectively, these data suggest that the concentrations of sucralose detected in the environment are well below those required to elicit chronic effects in freshwater or marine invertebrates. PMID:21742009

  11. DNA damage and oxidative stress induced by acetylsalicylic acid in Daphnia magna.

    PubMed

    Gómez-Oliván, Leobardo Manuel; Galar-Martínez, Marcela; Islas-Flores, Hariz; García-Medina, Sandra; SanJuan-Reyes, Nely

    2014-08-01

    Acetylsalicylic acid is a nonsteroidal anti-inflammatory widely used due to its low cost and high effectiveness. This compound has been found in water bodies worldwide and is toxic to aquatic organisms; nevertheless its capacity to induce oxidative stress in bioindicators like Daphnia magna remains unknown. This study aimed to evaluate toxicity in D. magna induced by acetylsalicylic acid in water, using oxidative stress and DNA damage biomarkers. An acute toxicity test was conducted in order to determine the median lethal concentration (48-h LC50) and the concentrations to be used in the subsequent subacute toxicity test in which the following biomarkers were evaluated: lipid peroxidation, oxidized protein content, activity of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, and level of DNA damage. Lipid peroxidation level and oxidized protein content were significantly increased (p<0.05), and antioxidant enzymes significantly altered with respect to controls; while the DNA damage were significantly increased (p<0.05) too. In conclusion, acetylsalicylic acid induces oxidative stress and DNA damage in D. magna. PMID:24747829

  12. [Thermal preference and avoidance in cladoceran Daphnia magna strauss (Crustacea, Cladocera) acclimated to constant temperature].

    PubMed

    Verbitskiĭ, V B; Verbitskaia, T I

    2012-01-01

    The final preferable temperature (FPT) and avoidance temperature (AT) were determined in parthenogenetic females of the crustacean Daphnia magna Strauss. The animals were preliminary acclimated to constant temperature of 23.4 degrees C followed by keeping them in a thermo-gradient device for 24 days. It was revealed that daphnia select FPT with overshoot. In the first four days, daphnia selected temperatures 0.6-1.6 degrees C higher than the acclimation temperature and 4-7.4 degrees C higher than FPT. Two zones of FPT are revealed: the first zone by the time of 5-13 days (17.6 +/- 1.2 degrees C); the second, by 16-24 days (20 +/- 1.5 degrees C). The dynamics of AT diapason followed the dynamics of FPT. Two zones of the AT plateau were observed: over five to 17 days (temperatures < 14 degrees C and > 25.8 degrees C were avoided) and for 21-24 days (< 8.5 degrees C and 26 degrees C). PMID:22567878

  13. Bioavailability of Pyrene Associated with Suspended Sediment of Different Grain Sizes to Daphnia magna as Investigated by Passive Dosing Devices.

    PubMed

    Zhang, Xiaotian; Xia, Xinghui; Li, Husheng; Zhu, Baotong; Dong, Jianwei

    2015-08-18

    Suspended sediment (SPS) is widely present in rivers around the world. However, the bioavailability of hydrophobic organic compounds (HOCs) associated with SPS is not well understood. In this work, the influence of SPS grain size on the bioavailability of SPS-associated pyrene to Daphnia magna was studied using a passive dosing device, which maintained a constant freely dissolved pyrene concentration (Cfree) in the exposure systems. The immobilization and protein as well as enzymatic activities of Daphnia magna were investigated to study the bioavailability of SPS-associated pyrene. With Cfree of pyrene ranging from 20.0 to 60.0 μg L(-1), the immobilization of Daphnia magna in the presence of 1 g L(-1) SPS was 1.11-2.89 times that in the absence of SPS. The immobilization caused by pyrene associated with different grain size SPS was on the order of 50-100 μm > 0-50 μm > 100-150 μm. When pyrene Cfree was 20.0 μg L(-1), the immobilization caused by pyrene associated with 50-100 μm SPS was 1.42 and 2.43 times that with 0-50 and 100-150 μm SPS, respectively. The protein and enzymatic activities of Daphnia magna also varied with the SPS grain size. The effect of SPS grain size on the bioavailability of SPS-associated pyrene was mainly due to the difference in SPS ingestion by Daphnia magna and SPS composition, especially the organic carbon type, among the three size fractions. This study suggests that not only the concentration but also the size distribution of SPS should be considered for the development of a biological effect database and establishment of water quality criteria for HOCs in natural waters. PMID:26199982

  14. The Effects of Natural and Anthropogenic Microparticles on Individual Fitness in Daphnia magna.

    PubMed

    Ogonowski, Martin; Schür, Christoph; Jarsén, Åsa; Gorokhova, Elena

    2016-01-01

    Concerns are being raised that microplastic pollution can have detrimental effects on the feeding of aquatic invertebrates, including zooplankton. Both small plastic fragments (microplastics, MPs) produced by degradation of larger plastic waste (secondary MPs; SMPs) and microscopic plastic spheres used in cosmetic products and industry (primary MPs; PMPs) are ubiquitously present in the environment. However, despite the fact that most environmental MPs consist of weathered plastic debris with irregular shape and broad size distribution, experimental studies of organism responses to MP exposure have largely used uniformly sized spherical PMPs. Therefore, effects observed for PMPs in such experiments may not be representative for MP-effects in situ. Moreover, invertebrate filter-feeders are generally well adapted to the presence of refractory material in seston, which questions the potential of MPs at environmentally relevant concentrations to measurably affect digestion in these organisms. Here, we compared responses to MPs (PMPs and SMPs) and naturally occurring particles (kaolin clay) using the cladoceran Daphnia magna as a model organism. We manipulated food levels (0.4 and 9 μg C mL-1) and MP or kaolin contribution to the feeding suspension (<1 to 74%) and evaluated effects of MPs and kaolin on food uptake, growth, reproductive capacity of the daphnids, and maternal effects on offspring survival and feeding. Exposure to SMPs caused elevated mortality, increased inter-brood period and decreased reproduction albeit only at high MP levels in the feeding suspension (74% by particle count). No such effects were observed in either PMP or kaolin treatments. In daphnids exposed to any particle type at the low algal concentration, individual growth decreased by ~15%. By contrast, positive growth response to all particle types was observed at the high algal concentration with 17%, 54% and 40% increase for kaolin, PMP and SMP, respectively. When test particles comprised

  15. The Effects of Natural and Anthropogenic Microparticles on Individual Fitness in Daphnia magna

    PubMed Central

    Schür, Christoph; Jarsén, Åsa; Gorokhova, Elena

    2016-01-01

    Concerns are being raised that microplastic pollution can have detrimental effects on the feeding of aquatic invertebrates, including zooplankton. Both small plastic fragments (microplastics, MPs) produced by degradation of larger plastic waste (secondary MPs; SMPs) and microscopic plastic spheres used in cosmetic products and industry (primary MPs; PMPs) are ubiquitously present in the environment. However, despite the fact that most environmental MPs consist of weathered plastic debris with irregular shape and broad size distribution, experimental studies of organism responses to MP exposure have largely used uniformly sized spherical PMPs. Therefore, effects observed for PMPs in such experiments may not be representative for MP-effects in situ. Moreover, invertebrate filter-feeders are generally well adapted to the presence of refractory material in seston, which questions the potential of MPs at environmentally relevant concentrations to measurably affect digestion in these organisms. Here, we compared responses to MPs (PMPs and SMPs) and naturally occurring particles (kaolin clay) using the cladoceran Daphnia magna as a model organism. We manipulated food levels (0.4 and 9 μg C mL-1) and MP or kaolin contribution to the feeding suspension (<1 to 74%) and evaluated effects of MPs and kaolin on food uptake, growth, reproductive capacity of the daphnids, and maternal effects on offspring survival and feeding. Exposure to SMPs caused elevated mortality, increased inter-brood period and decreased reproduction albeit only at high MP levels in the feeding suspension (74% by particle count). No such effects were observed in either PMP or kaolin treatments. In daphnids exposed to any particle type at the low algal concentration, individual growth decreased by ~15%. By contrast, positive growth response to all particle types was observed at the high algal concentration with 17%, 54% and 40% increase for kaolin, PMP and SMP, respectively. When test particles comprised

  16. How reliable are data for the ecotoxicity of trivalent chromium to Daphnia magna?

    PubMed

    Ponti, Benedetta; Bettinetti, Roberta; Dossi, Carlo; Vignati, Davide Anselmo Luigi

    2014-10-01

    Risk assessments from the European Union and the World Health Organization report values for acute and chronic toxicity of Cr(III) to Daphnia magna in the range of 0.6 mg/L to 111 mg/L and 0.047 mg/L to 3.4 mg/L, respectively. To understand whether factors other than the use of different test media and data reporting contribute to this variability, the authors tested the acute (48-h) and chronic (21-d) toxicities of Cr(III) to D. magna according to Organisation for Economic Co-operation and Development (OECD) methods. Filterable (0.45-µm) chromium concentrations were measured at 0 h, 6 h, 24 h, and 48 h, the latter value corresponding to the total duration of the acute tests and to the interval between medium renewals in chronic tests. In highly alkaline media (4.9 meq/L), Cr concentrations decreased rapidly below the analytical detection limit, and no toxicity was observed. In less alkaline media (approximately 0.8 meq/L), the decrease in filterable Cr concentrations was inversely proportional to the quantity of added Cr(III). The authors concluded that existing data likely underestimate the ecotoxicity of Cr(III) to D. magna. A reliable assessment of the hazard of Cr(III) to D. magna must consider that exposure concentrations can decrease markedly from the beginning to the end of a test and that medium alkalinity strongly influences the outcome of laboratory toxicity tests. PMID:24943496

  17. Effects of algal food quality on sexual reproduction of Daphnia magna.

    PubMed

    Choi, Jong-Yun; Kim, Seong-Ki; La, Geung-Hwan; Chang, Kwang-Hyeon; Kim, Dong-Kyun; Jeong, Keon-Young; Park, Min S; Joo, Gea-Jae; Kim, Hyun-Woo; Jeong, Kwang-Seuk

    2016-05-01

    The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long-chain poly unsaturated fatty acids (PUFAs), we hypothesized that the diatom-consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga (Chlorella vulgaris) and a diatom (Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long-chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem. PMID:27217941

  18. A comparison of the response of Simocephalus mixtus (Cladocera) and Daphnia magna to contaminated freshwater sediments.

    PubMed

    Martínez-Jerónimo, Fernando; Cruz-Cisneros, Jade Lizette; García-Hernández, Leonardo

    2008-09-01

    The southeast region of Mexico is characterized by intensive oil industry activities carried out by the national public enterprise Petróleos Mexicanos (PEMEX). The freshwater lagoon "El Limón", located in the municipality of Macuspana, state of Tabasco, Mexico, has received over 40 years discharges of untreated waste waters from the Petrochemical Complex "Ciudad PEMEX", located on the border of the lagoon. To assess the toxicity of the sediments and, hence, to obtain information on the biological effects of these contaminating discharges, the cladoceran Simocephalus mixtus was used as a test organism in acute (48h) and chronic (12d) toxicity assays. For comparison purposes, bioassays were also conducted with the reference cladoceran Daphnia magna. The sediments of this lagoon contain important amounts of metals and hydrocarbons that have been accumulated over time; however, the acute tests only registered reduced lethal effects on the test organisms (maxima of 10% and 17% mortality for D. magna and S. mixtus, respectively). This may be due to low bioavailability of the pollutants present in the sediments. On the other hand, partial or total inhibition and delay in the start of reproduction, reduction in clutch sizes, reduced survival, as well as reduction in the size of adults and offspring were recorded in the chronic assays. The most evident chronic effects were found in S. mixtus; in this species, reproduction was inhibited up to 72%, whereas D. magna was only affected by 24%. We determined that S. mixtus is a more sensitive test organism than D. magna to assess whole-sediment toxicity in tropical environments, and that chronic exposure bioassays are required for an integrated sediment evaluation. The sediments from "El Limón" lagoon induced chronic intoxication responses and, therefore, remediation measures are urgently needed to recover environmental conditions suitable for the development of its aquatic biota. PMID:18573528

  19. Hormetic response of cholinesterase from Daphnia magna in chronic exposure to triazophos and chlorpyrifos.

    PubMed

    Li, Shaonan; Tan, Yajun

    2011-01-01

    In vivo activity of cholinesterase (ChE) in Daphnia magna was measured at different time points during 21-day exposure to triazophos and chlorpyrifos ranging from 0.05 to 2.50 microg/L and 0.01 to 2.00 microg/L, respectively. For exposure to triazophos, ChE was induced up to 176.5% at 1.5 microg/L and day 10 when measured by acetylthiocholine (ATCh), whereas it was induced up to 174.2% at 0.5 microg/L and day 10 when measured by butyrylthiocholine (BTCh). For exposure to chlorpyrifos, ChE was induced up to 134.0% and 160.5% when measured by ATCh and BTCh, respectively, with both maximal inductions detected at 0.1 microg/L and day 8. Obvious induction in terms of ChE activity was also detected in daphnia removed from exposures 24 hr after their birth and kept in a recovery culture for 21 days. Results indicated that the enzyme displayed symptoms of hormesis, a characteristic featured by conversion from low-dose stimulation to high-dose inhibition. In spite of that, no promotion in terms of reproduction rate and body size was detected at any tested concentrations regardless of whether the daphnia were collected at end of the 21-day exposure or at end of a 21-day recovery culture. This suggested that induction of ChE caused by anticholinesterases had nothing to do with the prosperity of the daphnia population. PMID:21790060

  20. Assessment of the toxicity of a pesticide with a two-generation reproduction test using Daphnia magna.

    PubMed

    Sánchez, M; Ferrando, M D; Sancho, E; Andreu, E

    1999-11-01

    Daphnia magna (F0 generation) were exposed during 21 days to different diazinon concentrations. Offspring (animals from the first and third brood: F1 (1st) and F1 (3rd), respectively) were transferred to a free pesticide medium during a 21-day recovery period. The algae Nannochloris oculata (5x10(5) cells/ml) were used as food. In this recovery study, survival, growth and reproduction (mean total young per female, mean brood size, onset of reproduction and mean number broods per female) were assessed as individual parameters, and the intrinsic rate of natural increase (r) as population parameter for F1 (1st and 3rd broods) daphnids. Reproduction as well as survival was still reduced in F1 (1st) generation daphnids from parentals (F0) exposed to the highest diazinon concentration. However, F1 (1st) and F1 (3rd) individuals from parentals exposed to pesticide concentrations below 0.5 ng/l were able to restore reproduction and survival when a recovery period of 21 days was allowed. PMID:10661716

  1. Bisphenol A migration from plastic materials: direct insight of ecotoxicity in Daphnia magna.

    PubMed

    Mansilha, Catarina; Silva, Poliana; Rocha, Sónia; Gameiro, Paula; Domingues, Valentina; Pinho, Carina; Ferreira, Isabel M P L V O

    2013-09-01

    Bisphenol A (BPA) is an endocrine disrupting chemical (EDC) whose migration from food packaging is recognized worldwide. However, the real overall food contamination and related consequences are yet largely unknown. Among humans, children's exposure to BPA has been emphasized because of the immaturity of their biological systems. The main aim of this study was to assess the reproductive impact of BPA leached from commercially available plastic containers used or related to child nutrition, performing ecotoxicological tests using the biomonitoring species Daphnia magna. Acute and chronic tests, as well as single and multigenerational tests were done. Migration of BPA from several baby bottles and other plastic containers evaluated by GC-MS indicated that a broader range of foodstuff may be contaminated when packed in plastics. Ecotoxicological test results performed using defined concentrations of BPA were in agreement with literature, although a precocious maturity of daphnids was detected at 3.0 mg/L. Curiously, an increased reproductive output (neonates per female) was observed when daphnids were bred in the polycarbonate (PC) containers (145.1 ± 4.3 % to 264.7 ± 3.8 %), both in single as in multigenerational tests, in comparison with the negative control group (100.3 ± 1.6 %). A strong correlated dose-dependent ecotoxicological effect was observed, providing evidence that BPA leached from plastic food packaging materials act as functional estrogen in vivo at very low concentrations. In contrast, neonate production by daphnids cultured in polypropylene and non-PC bottles was slightly but not significantly enhanced (92.5 ± 2.0 % to 118.8 ± 1.8 %). Multigenerational tests also revealed magnification of the adverse effects, not only on fecundity but also on mortality, which represents a worrying trend for organisms that are chronically exposed to xenoestrogens for many generations. Two plausible explanations for the observed results

  2. The uptake of ZnO and CuO nanoparticles in the water-flea Daphnia magna under acute exposure scenarios.

    PubMed

    Adam, Nathalie; Leroux, Frédéric; Knapen, Dries; Bals, Sara; Blust, Ronny

    2014-11-01

    In this study the uptake of ZnO and CuO nanoparticles by Daphnia magna was tested. Daphnids were exposed during 48 h to acute concentrations of the nanoparticles and corresponding metal salts. The Daphnia zinc and copper concentration was measured and the nanoparticles were localized using electron microscopy. The aggregation and dissolution in the medium was characterized. A fast dissolution of ZnO in the medium was observed, while most CuO formed large aggregates and only a small fraction dissolved. The Daphnia zinc concentration was comparable for the nanoparticles and salts. Contrarily, a much higher Daphnia copper concentration was observed in the CuO exposure, compared to the copper salt. CuO nanoparticles adsorbed onto the carapace and occurred in the gut but did not internalize in the tissues. The combined dissolution and uptake results indicate that the toxicity of both nanoparticle types was caused by metal ions dissolved from the particles in the medium. PMID:25108488

  3. Mixture toxicity effects of sea louse control agents in Daphnia magna.

    PubMed

    Rose, Stephanie; Altenburger, Rolf; Sturm, Armin

    2016-02-01

    Caligid sea lice are ectoparasites causing major disease problems in industrial salmon farming. Sea louse control currently relies widely on parasiticides. Among non-target species, crustaceans are particularly susceptible to salmon delousing agents. Drug combinations have recently been suggested for sea louse control; however, no information is available on the non-target effects of such mixtures. To obtain first insights into combination effects of salmon parasiticides, acute toxicity tests with the crustacean model species Daphnia magna were conducted. Four compounds, including two organophosphates and two pyrethroids, were tested individually and in all pair-wise combinations at one fixed concentration ratio. For most combinations, observed toxicities were close to predictions assuming concentration additivity. However, deltamethrin and cypermethrin showed greater than predicted combination effects, while the inverse was observed for deltamethrin and malathion. The results demonstrate combination effects of anti-sea louse agents and suggest that predictions based on concentration additivity are in most cases protective. PMID:26401637

  4. Infections by Pasteuria do not protect its natural host Daphnia magna from subsequent infections.

    PubMed

    Duneau, David; Ebert, Dieter; Du Pasquier, Louis

    2016-04-01

    The existence of immunological memory in invertebrates remains a contentious topic. Exposure of Daphnia magna crustaceans to a noninfectious dose of the bacterium Pasteuria ramosa has been reported to reduce the chance of future infection upon exposure to higher doses. Using clonal hosts and parasites, we tested whether initial exposure of the host to the parasite (priming), followed by clearing of the parasite with antibiotic, protects the host from a second exposure (challenge). Our experiments included three treatments: priming and challenge with the same or with a different parasite clone, or no priming. Two independent experiments showed that both the likelihood of infection and the degree of parasite proliferation did not differ between treatments, supporting the conclusion that there is no immunological memory in this system. We discuss the possibility that previous discordant reports could result from immune or stress responses that did not fade following initial priming. PMID:26709232

  5. Acute and chronic toxicity of buprofezin on Daphnia magna and the recovery evaluation.

    PubMed

    Liu, Yong; Qi, Suzhen; Zhang, Wen; Li, Xuefeng; Qiu, Lihong; Wang, Chengju

    2012-11-01

    The toxic effects of buprofezin on Daphnia magna after both chronic and acute exposures were evaluated according to OECD guidelines. A 48-h acute exposure of buprofezin resulted in daphnid immobility at an EC(50) of 0.44 mg/L. In a 14 days chronic exposure of buprofezin (0, 0.025, 0.05, 0.10 and 0.15 mg/L), the development and reproduction of daphnids were all significantly affected and the body length was more sensitive than other observed parameters. However, the adverse effects of buprofezin on parental daphnids can be passed on to their offspring and cannot be recovered in a short time. PMID:22940740

  6. Population developmental stage determines the recovery potential of Daphnia magna populations after fenvalerate application.

    PubMed

    Pieters, Barry J; Liess, Matthias

    2006-10-01

    This study investigated the responses of Daphnia magna populations to pulsed exposures of the pyrethroid insecticide Fenvalerate applied during an early and a late stage of population development, and analyzed the dynamics of the subsequent recovery. A novel digital observation technique was used to describe the size and numbers of animals. High Fenvalerate concentrations caused high mortality rates during exponential population growth as well as during the food-limited stationary phase. However, recovery of populations took considerably longer in the stationary phase than in populations growing exponentially. The poor nutritional and reproductive state of food-deprived adults was indicated as the main cause of the slow recovery of populations. It is argued that populations operating at the carrying capacity of their environment are vulnerable to toxicant-induced disturbances to an extent not predictable from observations on exponentially growing populations such as are commonly used in ecotoxicology. PMID:17051815

  7. Joint Toxicity of Two Phthalates with Waterborne Copper to Daphnia magna and Photobacterium phosphoreum.

    PubMed

    Huang, Boyang; Li, Dinglong; Yang, Yan

    2016-09-01

    Di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) are two widely used phthalates, while Cu(II) is a common valence state of copper. They have been ubiquitously detected in the aquatic environment, but information on their joint toxicity to aquatic organisms is scarce. In this study, we evaluated the combined effects of copper and these two phthalates to Daphnia magna and Photobacterium phosphoreum by quantifying the acute toxicity expressed by the EC50 (the concentration causing 50 % of maximal effect) value. The toxicity order was DEHP + Cu(II) > DBP + Cu(II) > Cu(II) > DEHP > DBP for both test species. Antagonism effects were found in the joint toxicity of Cu(II) combined with DBP or DEHP using the toxic unit method. These findings have important implications in environmental risk assessment for phthalates in the aquatic environment in the presence of heavy metals. PMID:27385371

  8. Gravity Perception in a Cladoceran-zooplankter: Anatomy of Antennal Socket Setae of Daphnia Magna

    NASA Technical Reports Server (NTRS)

    Meyers, D. G.

    1985-01-01

    Night orientation in Daphnia magna was recently associated with setae on the basal socket of the swimming antennae. Daphnids are suspected of maintaining nocturnal equilibrium by monitoring the gravity vector through upward setal deflections caused by sinking between antennal swimming strokes. Setae appear to be hydrodynamic rheoceptors that sense the gravity vector indirectly by mechanoreceptivity to the direction and velocity of water currents. Neuroanatomical stains have revealed cell bodies at the base of the setal shafts, dendritic connections through to the distal ends of the shafts, and axonal tracts around the antennal socket connecting with an additional cell body and continuing toward the brain. These anatomical observations combined with previous scanning electron microscopy studies suggest that the setae are similar to mechanoreceptors and propreceptors used by higher crustaceans to sense water currents and gravity, and maintained balance.

  9. Chronic effects of Pinus radiata and Eucalyptus globulus kraft mill effluents and phytosterols on Daphnia magna.

    PubMed

    López, D; Chamorro, S; Silva, J; Bay-Schmith, E; Vidal, G

    2011-12-01

    Two kraft pulp mill effluents were compared in terms of their chronic toxicity to Daphnia magna. One resulted from pulping Pinus radiata and the other came from a parallel processing of Pinus radiata and Eucalyptus globulus (mixed kraft pulp mill effluent). The concentration of phytosterols found in the mixed kraft pulp mill effluent was higher than in the effluent from Pinus radiata, with values of 0.1082 and 0.02 μg/L, respectively. The phytosterols per se are responsible for 12.9% and 8.1% of the deviation from the natural shape, while the kraft pulp mill effluents account for 25.6%-27.8% of shape deviation. The role of β-sitosterol and stigmasterol is discussed in relation to endocrine disruption. PMID:21979137

  10. Feeding inhibition explains effects of imidacloprid on the growth, maturation, reproduction, and survival of Daphnia magna.

    PubMed

    Agatz, Annika; Cole, Tabatha A; Preuss, Thomas G; Zimmer, Elke; Brown, Colin D

    2013-03-19

    Effects of some xenobiotics on aquatic organisms might not be caused directly by the compound but rather arise from acclimation of the organism to stress invoked by feeding inhibition during exposure. Experiments were conducted to identify effects of imidacloprid on individual performance (feeding, growth, maturation, reproduction, and survival) of Daphnia magna under surplus and reduced food availability. Concentrations inhibiting feeding by 5, 50, and 95% after one day of exposure were 0.19, 1.83, and 8.70 mg/L, respectively. Exposure with imidacloprid at ≥ 3.7 mg/L reduced growth by up to 53 ± 11% within one week. Surplus food availability after inhibition allowed recovery from this growth inhibition, whereas limited food supply eliminated the potential for recovery in growth even for exposure at 0.15 mg/L. A shift in the distribution of individual energy reserves toward reproduction rather than growth resulted in increased reproduction after exposure to concentrations ≤ 0.4 mg/L. Exposure to imidacloprid at ≥ 4.0 mg/L overwhelmed this adaptive response and reduced reproduction by up to 57%. We used the individual based Daphnia magna population model IDamP as a virtual laboratory to demonstrate that only feeding was affected by imidacloprid, and that in turn this caused the other impacts on individual performance. Consideration of end points individually would have led to a different interpretation of the effects. Thus, we demonstrate how multiple lines of evidence linked by understanding the ecology of the organism are necessary to elucidate xenobiotic impacts along the effect cascade. PMID:23425205

  11. The effects of lead on delta-aminolevulinic acid dehydratase activity, growth, hemoglobin content, and reproduction in Daphnia magna.

    PubMed

    Berglind, R; Dave, G; Sjöbeck, M L

    1985-04-01

    The effects of continuous exposure to lead for various periods and recovery in clean water on delta-aminolevulinic acid dehydratase (ALA-D) activity, hemoglobin content, growth, and reproduction were studied in Daphnia magna. Steady-state inhibition of ALA-D activity was reached within 2 days in 16, 64, and 256 micrograms Pb liter-1, but restoration in clean water was prolonged in relation to previous exposure. In spite of the inhibition of ALA-D activity hemoglobin content increased after 2 days in 16 and 24 micrograms Pb liter-1. Furthermore, hemoglobin content in previously exposed animals increased during recovery in clean water. Maximum hemoglobin content (2.9 times control value) was found after 2 days recovery of animals exposed to 64 micrograms Pb liter-1. These findings suggest that some enzyme(s) other than ALA-D in the biosynthetic pathway of hemoglobin formation is (are) more sensitive to lead. Growth, in contrast to reproduction, was stimulated by low concentrations of lead (less than 64 micrograms Pb liter-1), although in 256 micrograms Pb liter-1 growth was also significantly impaired. After 19 days the 16 and 50% reproductive impairment concentrations were less than or equal to 1 and 10 micrograms Pb liter-1, respectively. PMID:3987601

  12. Effects of lead on delta-aminolevulinic acid dehydratase activity, growth, hemoglobin content, and reproduction in Daphnia magna

    SciTech Connect

    Berglind, R.; Dave, G.; Sjoebeck, M.L.

    1985-04-01

    The effects of continuous exposure to lead for various periods and recovery in clean water on delta-aminolevulinic acid dehydratase (ALA-D) activity, hemoglobin content, growth, and reproduction were studied in Daphnia magna. Steady-state inhibition of ALA-D activity was reached within 2 days in 16, 64, and 256 micrograms Pb liter-1, but restoration in clean water was prolonged in relation to previous exposure. In spite of the inhibition of ALA-D activity hemoglobin content increased after 2 days in 16 and 24 micrograms Pb liter-1. Furthermore, hemoglobin content in previously exposed animals increased during recovery in clean water. Maximum hemoglobin content (2.9 times control value) was found after 2 days recovery of animals exposed to 64 micrograms Pb liter-1. These findings suggest that some enzyme(s) other than ALA-D in the biosynthetic pathway of hemoglobin formation is (are) more sensitive to lead. Growth, in contrast to reproduction, was stimulated by low concentrations of lead (less than 64 micrograms Pb liter-1), although in 256 micrograms Pb liter-1 growth was also significantly impaired. After 19 days the 16 and 50% reproductive impairment concentrations were less than or equal to 1 and 10 micrograms Pb liter-1, respectively.

  13. Toxicity of pulse exposures of zinc, cadmium, and copper to pre-exposed trout and Daphnia

    SciTech Connect

    Cohen, A.S.; Hockett, J.R.; Stubblefield, W.A.; Mount, D.R.

    1994-12-31

    Previous studies have demonstrated that the sensitivity of fish to metals decreases following pre-exposure to sub-lethal concentrations. However, little information is available regarding the acclimatory capacity of invertebrate species or the ability of organisms to withstand brief (< 96 hr), high concentration pulse exposures to metals. Studies were conducted to investigate these issues. Groups of rainbow and brown trout were exposed for 1 0 days to single metals (Zn, Cu, and Cd) concentrations equal to 0.5 of the previously determined Incipient Lethal Level (ILL). Daphnia were similarly exposed for 24 hours to 0.5 of the predetermined 48-hr LC{sub 50}. Pre-exposed and naive (nonexposed) trout and D. magna were challenged with single 4-hr pulse exposures to each metal; organisms were monitored for a total of 96 and 48 hrs, respectively. Study results confirm a general increase in the ability of pre-exposed trout and D. magna to withstand subsequent pulse exposures. The magnitude of acquired tolerance varied depending on species and metal, but generally ranged from 1.2 to 5.9 times that of naive organisms.

  14. Trophic transfer of differently functionalized zinc oxide nanoparticles from crustaceans (Daphnia magna) to zebrafish (Danio rerio).

    PubMed

    Skjolding, L M; Winther-Nielsen, M; Baun, A

    2014-12-01

    The potential uptake and trophic transfer of nanoparticles (NP) is not well understood so far and for ZnO NP the data presented in peer-reviewed literature is limited. In this paper the influence of surface functionalization on the uptake and depuration behavior of ZnO NP, ZnO-OH NP and ZnO-octyl NP in D. magna was studied. Bulk ZnO particles (≤5 μm) and ZnCl2 were used as references for uptake of particles and dissolved species of Zn, respectively. Furthermore, the trophic transfer of ZnO NP and ZnO-octyl NP from daphnids (Daphnia magna) to zebra fish (Danio rerio) was studied. For ZnO NP and ZnO-octyl NP fast uptakes in D. magna were observed, whereas no measurable uptake took place for ZnO-OH NP. Lower body burden of ZnCl2 was found compared to both ZnO NP and ZnO-octyl. Contrary, the body burden for bulk ZnO was higher than that of ZnO NP but lower than ZnO-octyl. The higher body burdens found for functionalized ZnO-octyl NP than for non-functionalized ZnO NP showed that that the functionalization of the NP has a high influence on the uptake and depuration behavior. Though no mortality was observed, the resulting body burdens were 9.6 times (ZnO NP) and 47 times (ZnO-octyl NP) higher than toxic levels reported for zinc in D. magna. Consequently, the zinc recovered in the animals was not solely due to soluble zinc, but agglomerates/aggregates of ZnO NP or ZnO-octyl NP contributed to the body burdens. The trophic transfer study showed uptake of both ZnO NP and ZnO-octyl NP reaching more than tenfold higher levels than those obtained through aqueous exposure in other studies. This study contributes to expand the available data on uptake behavior of differently functionalized ZnO NP in D. magna and the potential trophic transfer from zooplankton to fish. PMID:25456224

  15. Aquatic toxicity of cartap and cypermethrin to different life stages of Daphnia magna and Oryzias latipes.

    PubMed

    Kim, Younghee; Jung, Jinyong; Oh, Sorin; Choi, Kyungho

    2008-01-01

    Cartap and cypermethrin, which are among the most widely used pesticides in many countries, are considered safe because of their low mammalian toxicity and their low persistence in the environment. However, recent findings of endocrine-disrupting effects and developmental neurotoxicity have raised concerns about the potential ecological impacts of these pesticides. We evaluated the aquatic toxicity of cartap [S,S'-(2-dimethylaminotrimethylene) bis(thiocarbamate), unspecified hydrochloride] and cypermethrin [(RS)-alpha-cyano-3-phenoxybenzyl-(1RS,3RS,1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate], both individually and combined, on different life stages of the freshwater cladoceran Daphnia magna and a freshwater teleost, Japanese medaka (Oryzias latipes). The 96-hr Daphnia median effective concentrations (EC50s) for cartap and cypermethrin were 91.0 microg/L and 0.00061 microg/L, respectively. Rapid recovery of Daphnia was observed after short-term pulsed exposure to cartap and cypermethrin; there were no adverse effects on reproduction or survival 20 d after a 24 hr exposure to cartap up to 1240 microg/L and cypermethrin up to 1.9 microg/L. Chronic continuous exposure (for 21 d) of 7-d-old Daphnia to cypermethrin significantly reduced the intrinsic population growth rate in a concentration-dependent manner. However, because the intrinsic population growth rates were all above zero, populations did not decrease even at the highest experimental concentration of 200 ng/L. Exposure of Daphnia neonates (< 24 hr old) to cypermethrin for 21 d caused significant, sub-lethal reproduction-related problems, such as increased time to first brood, reduced brood size, and reduced total brood number, at 0.0002, 0.002, and 0.2 ng/L cypermethrin, but the intrinsic population growth rate was not significantly affected. Oryzias latipes was relatively more resistant to both pesticides. In particular, embryos appeared to be more resistant than juveniles or adults

  16. Comparison of ethanol toxicity to Daphnia magna and Ceriodaphnia dubia tested at two different temperatures: static acute toxicity test results

    SciTech Connect

    Takahashi, I.T.; Cowgill, U.M.; Murphy, P.G.

    1987-08-01

    Ethanol is a commonly used solvent in toxicity testing, yet there are few studies in the literature devoted to its toxicity to zooplankton. The purpose of this study was to compare the response of Daphnia magna Straus 1820 and Ceriodaphnia dubia J. Richard 1894 to ethanol. Two temperatures were selected because most toxicity data involving D. magna has been carried out at 20/sup 0/C while all discussions concerning C. dubia appear to relate to temperatures oscillating around 25/sup 0/C. Thus, the response of these two organisms to ethanol was examined at 20/sup 0/C and at 24/sup 0/C.r

  17. Increased risk of phosphorus limitation at higher temperatures for Daphnia magna.

    PubMed

    Persson, Jonas; Wojewodzic, Marcin Włodzimierz; Hessen, Dag Olav; Andersen, Tom

    2011-01-01

    Invertebrate herbivores frequently face growth rate constraints due to their high demands for phosphorus (P) and nitrogen (N). Temperature is a key modulator of growth rate, yet the interaction between temperature and P limitation on somatic growth rate is scarcely known. To investigate this interaction, we conducted a study on the somatic growth rate (SGR) of the cladoceran Daphnia magna, known to be susceptible to P-limitation. We determined the SGR across a broad range of dietary P content of algae (carbon (C):P ratios (125-790), and at different temperatures (10-25°C). There was a strong impact of both temperature and C:P ratio on the SGR of D. magna, and also a significant interaction between both factors was revealed. The negative effect of dietary C:P on growth rate was reduced with decreased temperature. We found no evidence of P limitation at lowest temperature, suggesting that enzyme kinetics or other measures of food quality overrides the demands for P to RNA and protein synthesis at low temperatures. These findings also indicate an increased risk of P limitation and thus reduced growth efficiency at high temperatures. PMID:20803219

  18. Ecotoxicological assessment of grey water treatment systems with Daphnia magna and Chironomus riparius.

    PubMed

    Hernández Leal, L; Soeter, A M; Kools, S A E; Kraak, M H S; Parsons, J R; Temmink, H; Zeeman, G; Buisman, C J N

    2012-03-15

    In order to meet environmental quality criteria, grey water was treated in four different ways: 1) aerobic 2) anaerobic+aerobic 3) aerobic+activated carbon 4) aerobic+ozone. Since each treatment has its own specific advantages and disadvantages, the aim of this study was to compare the ecotoxicity of differently treated grey water using Chironomus riparius (96 h test) and Daphnia magna (48 h and 21d test) as test organisms. Grey water exhibited acute toxicity to both test organisms. The aerobic and combined anaerobic+aerobic treatment eliminated mortality in the acute tests, but growth of C. riparius was still affected by these two effluents. Post-treatment by ozone and activated carbon completely removed the acute toxicity from grey water. In the chronic toxicity test the combined anaerobic+aerobic treatment strongly affected D. magna population growth rate (47%), while the aerobic treatment had a small (9%) but significant effect. Hence, aerobic treatment is the best option for biological treatment of grey water, removing most of the toxic effects of grey water. If advanced treatment is required, the treatment with either ozone or GAC were shown to be very effective in complete removal of toxicity from grey water. PMID:22197265

  19. Predicting the toxicity of permethrin to Daphnia magna in water using SPME fibers.

    PubMed

    Harwood, Amanda D; Bunch, Aubrey R; Flickinger, Dallas L; You, Jing; Lydy, Michael J

    2012-04-01

    Multiple factors can influence bioavailability, which can make predictions of toxicity in natural systems difficult. The current study examined the potential use of solid-phase microextraction fibers as a matrix-independent approach to predict the toxicity of permethrin to Daphnia magna across various water sources, including a laboratory reconstituted water, two natural waters, and a modified natural water. Water source strongly affected the toxicity of permethrin as well as the concentration-response relationships. Although permethrin concentrations in the water were predictive of toxicity to D. magna for individual water sources, there was no relationship between permethrin concentrations among water sources and mortality. This indicated that compositional differences among water sources can greatly influence toxicity, suggesting that benchmarks established using reconstituted water may be overly conservative for some natural waters. In addition, although permethrin tissue residues were predictive of mortality for individual waters, the correlation among waters was not as clear. Finally, both 48-h and equilibrium-based SPME fiber concentrations adequately predicted toxicity independent of water properties. This demonstrated that bioavailability-based estimates provided a more accurate prediction of toxicity than water concentrations and that SPME fibers could be used in environmental monitoring as a rapid and accurate means of predicting toxicity in natural waters. PMID:22037820

  20. Importance of metallothioneins in the cadmium detoxification process in Daphnia magna.

    PubMed

    Fraysse, B; Geffard, O; Berthet, B; Quéau, H; Biagianti-Risbourg, S; Geffard, A

    2006-11-01

    Good knowledge of the relationship between toxic metals and biological systems, particularly the sub-cellular fraction, could be a suitable early indicator of toxic effects. These effects and the sub-cellular behaviour of cadmium were studied with a widely used species in freshwater toxicity bioassays, Daphnia magna. In spite of this very commonplace usage in ecotoxicological studies, very few data are available on its toxicant metabolism and in particular metal homeostasis. Combining multi-tools analysis, a soluble protein was found: it is heat-stable, rich in sulfhydryl groups (differential pulse polarography), characterised by a molecular mass of approximately 6.5 kDa, with a G-75 chromatographic profile corresponding to the rabbit metallothioneins monomer, with few if any aromatic-containing amino acids, it binds metals (e.g. Cd, Cu), and its concentration increases with Cd exposure. This evidence led us to hypothesise that metallothioneins (MTs) are present in D. magna. Up to 75% of the Cd body burden with Cd exposure is bound to the MTs fraction. The increase in the Cd concentration in the surrounding medium and concomitantly in daphnids induces sub-cellular reorganisation of essential metals such as Cu and Zn. The rate of metals in the soluble cellular fraction and associated with MTs increases with the Cd body burden. Monitoring sub-cellular distribution of metals after exposure in the natural environment could be very useful for ecotoxicological assessment. PMID:17113354

  1. Rapid evolution of antioxidant defence in a natural population of Daphnia magna.

    PubMed

    Oexle, S; Jansen, M; Pauwels, K; Sommaruga, R; De Meester, L; Stoks, R

    2016-07-01

    Natural populations can cope with rapid changes in stressors by relying on sets of physiological defence mechanisms. Little is known onto what extent these physiological responses reflect plasticity and/or genetic adaptation, evolve in the same direction and result in an increased defence ability. Using resurrection ecology, we studied how a natural Daphnia magna population adjusted its antioxidant defence to ultraviolet radiation (UVR) during a period with increasing incident UVR reaching the water surface. We demonstrate a rapid evolution of the induction patterns of key antioxidant enzymes under UVR exposure in the laboratory. Notably, evolutionary changes strongly differed among enzymes and mainly involved the evolution of UV-induced plasticity. Whereas D. magna evolved a strong plastic up-regulation of glutathione peroxidase under UVR, it evolved a lower plastic up-regulation of glutathione S-transferase and superoxide dismutase and a plastic down-regulation of catalase. The differentially evolved antioxidant strategies were collectively equally effective in dealing with oxidative stress because they resulted in the same high levels of oxidative damage (to lipids, proteins and DNA) and lowered fitness (intrinsic growth rate) under UVR exposure. The lack of better protection against UVR may suggest that the UVR exposure did not increase between both periods. Predator-induced evolution to migrate to lower depths that occurred during the same period may have contributed to the evolved defence strategy. Our results highlight the need for a multiple trait approach when focusing on the evolution of defence mechanisms. PMID:27018861

  2. Systems biology meets stress ecology: linking molecular and organismal stress responses in Daphnia magna

    PubMed Central

    Heckmann, Lars-Henrik; Sibly, Richard M; Connon, Richard; Hooper, Helen L; Hutchinson, Thomas H; Maund, Steve J; Hill, Christopher J; Bouetard, Anthony; Callaghan, Amanda

    2008-01-01

    Background Ibuprofen and other nonsteroidal anti-inflammatory drugs have been designed to interrupt eicosanoid metabolism in mammals, but little is known of how they affect nontarget organisms. Here we report a systems biology study that simultaneously describes the transcriptomic and phenotypic stress responses of the model crustacean Daphnia magna after exposure to ibuprofen. Results Our findings reveal intriguing similarities in the mode of action of ibuprofen between vertebrates and invertebrates, and they suggest that ibuprofen has a targeted impact on reproduction at the molecular, organismal, and population level in daphnids. Microarray expression and temporal real-time quantitative PCR profiles of key genes suggest early ibuprofen interruption of crustacean eicosanoid metabolism, which appears to disrupt signal transduction affecting juvenile hormone metabolism and oogenesis. Conclusion Combining molecular and organismal stress responses provides a guide to possible chronic consequences of environmental stress for population health. This could improve current environmental risk assessment by providing an early indication of the need for higher tier testing. Our study demonstrates the advantages of a systems approach to stress ecology, in which Daphnia will probably play a major role. PMID:18291039

  3. Consequences of calcium decline on the embryogenesis and life history of Daphnia magna.

    PubMed

    Giardini, Jamie-Lee; Yan, Norman D; Heyland, Andreas

    2015-07-01

    Ambient calcium is declining in thousands of soft-water lake habitats in temperate regions as a consequence of unsustainable forestry practices, decreased atmospheric calcium deposition and acidic deposition. As their exoskeleton is heavily reinforced with calcium, freshwater crustaceans have a high specific calcium requirement relative to other aquatic organisms. Daphnia, in particular, is an ideal crustacean for investigating the consequences of calcium decline because it is an abundant and important member of freshwater zooplankton communities. Although it has been established that adult and juvenile Daphnia have different tolerances to low ambient calcium as a result of their different life stage-specific calcium requirements, the consequences of declining calcium on embryonic development have never been investigated. Here, we describe the distribution of calcium in embryonic stages of D. magna and introduce a novel and easy to use staging scheme. We tested whether calcium can be traced from mothers to their offspring. Finally, we assessed the fitness consequences of maternal provisioning in limiting calcium environments. We found that while embryos require calcium for their development and moulting, they do not equilibrate with environmental calcium levels. Instead, we were able to trace calcium from mothers to their offspring. Furthermore, our data strongly suggest that females are faced with an allocation trade-off between providing calcium to their offspring and using it for growth and moulting. Together, these data provide novel insights into the consequences of calcium decline for freshwater zooplankton. PMID:25944923

  4. Whole effluent toxicity (WET) tests on wastewater treatment plants with Daphnia magna and Selenastrum capricornutum.

    PubMed

    Ra, Jin Sung; Kim, Hyun Koo; Chang, Nam Ik; Kim, Sang Don

    2007-06-01

    Whole effluent toxicity (WET) tests, with Daphnia magna and Selenastrum capricornutum, were introduced to evaluate the biological toxicities of effluents from the wastewater treatment plants (WWTPs) in Korea. In WET tests of WWTPs effluents, 33.3% (33/99) for D. magna and 92.6% (75/81) for S. capricornutum revealed greater than 1 toxic unit (TU), even though all the treatment plants investigated were operating in compliance with the regulations, as assessed using conventional monitoring methods (i.e., BOD and total concentration of N or P, etc). There were only minor differences in toxicities according to the types of influents (municipal and agro-industrial) in all treatment plants. However, the effluents treated by an activated sludge treatment process were found to exhibit significantly lower toxicity than those treated by rotating biological contactor (RBC) and extended aeration processes. The seasonal variations in the toxicity were lower in the summer compared to winter, which may have been due to the rainfall received to the sewage intake system during the former period. The impact of WET on river water was also investigated based on the discharge volume. At sites A and B, the total impact of toxicity to stream and river waters was observed to be 70.9% and 90.4% for D. magna and S. capricornutum, respectively. The other four small treatment plants (sites F, G, H and I), with relative discharging volumes between 0.001 and 0.002, contribute less than 1% to the total toxicity. PMID:17106776

  5. Comparison of nanosilver and ionic silver toxicity in Daphnia magna and Pimephales promelas.

    PubMed

    Hoheisel, Sarah M; Diamond, Steve; Mount, David

    2012-11-01

    The increasing use of nanosilver in consumer products and the likelihood of environmental exposure warrant investigation into the toxicity of nanosilver to aquatic organisms. A series of studies were conducted comparing the potency of nanosilver to ionic silver (Ag(+)) at acute and sublethal levels using two test organisms (Daphnia magna and Pimephales promelas). The 48-h D. magna median lethal concentration (LC50) of multiple sizes (10, 20, 30, and 50 nm) of commercially prepared nanosilver (nanoComposix) ranged from 4.31 to 30.36 µg total Ag L(-1) with increasing toxicity associated with decreasing particle size. A strong relationship between estimated specific particle surface area and acute toxicity was observed. Nanosilver suspensions (10 nm) treated with cation exchange resin to reduce the concentration of Ag(+) associated with it were approximately equally toxic to D. magna compared to untreated nanosilver (48-h LC50s were 2.15 and 2.79 µg total Ag L(-1), respectively). The 96-h LC50 and 7-d sublethal 20% effective concentrations (EC20s) for P. promelas were 89.4 and 46.1 µg total Ag L(-1), respectively, for 10 nm nanosilver and 4.70 and 1.37 µg total Ag L(-1), respectively, for Ag(+); the resulting ratios of 96-h LC50 to 7-d EC20 were not significantly different for nanosilver and ionic silver. Overall, these studies did not provide strong evidence that nanosilver either acts by a different mechanism of toxicity than ionic silver, or is likely to cause acute or lethal toxicity beyond that which would be predicted by mass concentration of total silver. This in turn suggests that regulatory approaches based on the toxicity of ionic silver to aquatic life would not be underprotective for environmental releases of nanosilver. PMID:22887018

  6. The uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna under chronic exposure scenarios.

    PubMed

    Adam, Nathalie; Leroux, Frédéric; Knapen, Dries; Bals, Sara; Blust, Ronny

    2015-01-01

    In this study, the uptake and elimination of ZnO and CuO nanoparticles in Daphnia magna was tested. Daphnids were exposed during 10 days to sublethal concentrations of ZnO and CuO nanoparticles and corresponding metal salts (ZnCl₂ and CuCl₂.2H₂O), after which they were transferred to unexposed medium for another 10 days. At different times during the exposure and none-exposure, the total and internal zinc or copper concentration of the daphnids was determined and the nanoparticles were localized in the organism using electron microscopy. The exposure concentrations were characterized by measuring the dissolved, nanoparticle and aggregated fraction in the medium. The results showed that the ZnO nanoparticles quickly dissolved after addition to the medium. Contrarily, only a small fraction (corresponding to the dissolved metal salt) of the CuO nanoparticles dissolved, while most of these nanoparticles formed large aggregates. Despite an initial increase in zinc and copper concentration during the first 48 h to 5 day exposure, the body concentration reached a plateau level that was comparable for the ZnO nanoparticles and ZnCl₂, but much higher for the CuO nanoparticles (with visible aggregates accumulating in the gut) than CuCl₂.2H₂O. During the remaining exposure and subsequent none-exposure phase, the zinc and copper concentration decreased fast to concentrations comparable with the unexposed daphnids. The results indicate that D. magna can regulate its internal zinc and copper concentration after exposure to ZnO and CuO nanoparticles, similar as after exposure to metal salts. The combined dissolution, accumulation and toxicity results confirm that the toxicity of ZnO and CuO nanoparticles is caused by the dissolved fraction. PMID:25462733

  7. Sublethal effects of the flame retardant intermediate hexachlorocyclopentadiene (HCCPD) on the gene transcription and protein activity of Daphnia magna.

    PubMed

    Houde, Magali; Carter, Barbara; Douville, Mélanie

    2013-09-15

    Hexachlorocyclopentadiene (HCCPD) is a chlorinated chemical of high production volume used as an intermediate in the production of flame retardants. HCCPD may be released to the environment during production, use, and as a result of product degradation. The objectives of this study were to evaluate sublethal effects of HCCPD exposure to Daphnia magna at environmentally relevant concentrations (0.0138-13.8 μg/L) using genomic tools (microarray and qPCR), enzyme activities, and life-history endpoints (survival, reproduction, and growth). In chronic exposures, no differences were observed in life-history endpoints (survival, time of first brood, time of first molt, molt frequency, number of neonates, and body length) between exposed organisms and controls. Microarray analyses indicated significant differential genomic transcription for 46 genes (p-value ≤ 0.05 and fold-change>2). Five identified genes were related to metabolic functions. Enzyme activities of α-amylase and trypsin, selected based on transcriptional responses, were evaluated in D. magna. Although trypsin activity was similar between treatments and controls, the activity of α-amylase significantly decreased with increasing HCCPD concentrations. On the chemical level, instability of HCCPD was observed in spiked culture media, most probably due to photolysis and biodegradation. HCCPD was not detected in surface water samples collected upstream and at the point of discharge of a major wastewater treatment plant effluent. Environmentally, rapid degradation of HCCPD could be outdone by its continuous release into aquatic ecosystems in specific areas of concern (e.g., vicinity of industries and hazardous sites). Toxicity results from this study highlight the use of genomics in the identification of biomarkers and help advance the science, and potential use, of multi-level biological approaches for environmental risk assessment. PMID:23820075

  8. Acute toxicity of chromate, DDT, PCP, TPBS, and zinc to Daphnia magna cultured in hard and soft water

    SciTech Connect

    Berglind, R.; Dave, G.

    1984-07-01

    The aim of this study was to compare the toxicity of five chemicals to water fleas (Daphnia magna) cultured in either hard to soft water. The toxicity tests were made in reconstituted waters and the five chemicals to be tested were, p,p'-DDT, pentachlorophenol (PCP), tetrapropylenbenzyl sulfonate (TPBS), potassium bichromate (K/sub 2/Cr/sub 2/O/sub 7/) and zincsulfate (ZnSO/sub 4/ x 7H/sub 2/O).

  9. Effect of the dispersion of oil in freshwater based on time-dependent Daphnia magna toxicity tests

    SciTech Connect

    Vindimian, E.; Vollat, B.; Garric, J. )

    1992-02-01

    The purpose of this work is the study of the time dependence of the acute toxicity of oil and dispersants on a sensitive freshwater organism: Daphnia magna. Two different oils were used: a crude oil from the southwest of France and a gas oil free from volatile substances after being equilibrated with atmosphere. Two commercial dispersants were used: British Petroleum Enersperse 1037 and Dasic Freshwater for this study.

  10. An evaluation of nickel toxicity to Ceriodaphnia dubia and Daphnia magna in a contaminated stream and in laboratory tests

    SciTech Connect

    Kszos, L.A.; Stewart, A.J.; Taylor, P.A. )

    1992-01-01

    Seven-day tests with Ceriodaphnia dubia were used to document ambient toxicity in two industrially contaminated streams in southeastern Tennessee. Low survival of Ceriodaphnia dubia was linked to concentrations of Ni below EPA water quality criteria. A toxicity identification evaluation consisting of Ceriodaphnia dubia, Daphnia magna, and Pimephales promelas toxicity tests with Ni, chemical analyses, and experiments with a Ni-selective resin were used to show that Ni was the primary toxicant in one of the streams. Nickel nitrate and Ni chloride were both extremely toxic to Ceriodaphnia dubia but were not very toxic to Pimephales promelas: Ni at a concentration of 7.5 [mu]g/l was lethal to Ceriodaphnia dubia within 7 d, but 16 mg/L Ni did not reduce survival or growth of Pimephales promelas. When dilution water with a hardness of 177 mg/L was used, 15.0 [mu]g/L killed all the Ceriodaphnia dubia in 7 d. Daphnia magna was less sensitive than Ceriodaphnia dubia to Ni: a concentration of 40 [mu]g/L significantly reduced fecundity but not survival in 21 d. In stream water containing 49 [mu]g/L Ni, 100% mortality of Ceriodaphnia dubia occurred in 7 d, but 70% of the Daphnia magna survived for 14 d. When the Ni in the stream water was reduced to 10 [mu]g/L with the resin, 60% of the Ceriodaphnia dubia lived for 7 d and all the animals reproduced; survival and reproduction of Daphnia magna remained high for all 14 d. Experiments with [sup 63]Ni showed that both species accumulated similar amounts of Ni, so the difference in toxicity was not a result of Ni uptake. The high sensitivity of Ceriodaphnia dubia to Ni and the lower than expected reduction in Ni toxicity to Ceriodaphnia dubia with increasing hardness have important implications for effluent and ambient testing and toxicity reduction efforts.