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Sample records for juvenile daphnia magna

  1. Comparative ovarian microarray analysis of juvenile hormone-responsive genes in water flea Daphnia magna: potential targets for toxicity.

    Science.gov (United States)

    Toyota, Kenji; Williams, Timothy D; Sato, Tomomi; Tatarazako, Norihisa; Iguchi, Taisen

    2017-03-01

    The freshwater zooplankton Daphnia magna has been extensively employed in chemical toxicity tests such as OECD Test Guidelines 202 and 211. Previously, it has been demonstrated that the treatment of juvenile hormones (JHs) or their analogues to female daphnids can induce male offspring production. Based on this finding, a rapid screening method for detection of chemicals with JH-activity was recently developed using adult D. magna. This screening system determines whether a chemical has JH-activity by investigating the male offspring inducibility. Although this is an efficient high-throughput short-term screening system, much remains to be discovered about JH-responsive pathways in the ovary, and whether different JH-activators act via the same mechanism. JH-responsive genes in the ovary including developing oocytes are still largely undescribed. Here, we conducted comparative microarray analyses using ovaries from Daphnia magna treated with fenoxycarb (Fx; artificial JH agonist) or methyl farnesoate (MF; a putative innate JH in daphnids) to elucidate responses to JH agonists in the ovary, including developing oocytes, at a JH-sensitive period for male sex determination. We demonstrate that induction of hemoglobin genes is a well-conserved response to JH even in the ovary, and a potential adverse effect of JH agonist is suppression of vitellogenin gene expression, that might cause reduction of offspring number. This is the first report demonstrating different transcriptomics profiles from MF and an artificial JH agonist in D. magna ovary, improving understanding the tissue-specific mode-of-action of JH. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Behavioral responses of juvenile Daphnia magna after exposure to glyphosate and glyphosate-copper complexes.

    Science.gov (United States)

    Hansen, Lone Rykær; Roslev, Peter

    2016-10-01

    Glyphosate (N-(phosphonomethyl)glycine) is the active ingredient in a range of popular broad-spectrum herbicide formulations. Glyphosate is a chelating agent that can form stable complexes with divalent metal ions including Cu(II). Little is known about the bioavailability and ecotoxicity of glyphosate-Cu(II) complexes to aquatic organisms. In this study, we used video tracking and behavior analysis to investigate sublethal effects of binary mixtures of glyphosate and Cu(II) to juvenile D. magna. Behavioral responses were quantified for individual D. magna after 24h and 48h exposure to glyphosate and glyhosate-Cu(II) mixtures. Sublethal concentrations resulted in decreases in swimming velocity, acceleration speed, and distance moved whereas inactive time of D. magna increased. Distance moved and inactive time were the most responsive parameters to glyphosate and glyphosate-Cu(II) exposure. On a molar basis, glyphosate-Cu(II) complexes appeared more toxic to D. magna than glyphosate alone. The 48h EC50 for glyphosate and glyphosate-Cu(II) determined from swimming distance were 75.2μM and 8.4μM, respectively. In comparison, traditional visual observation of mobility resulted in 48h EC50 values of 52.8μM and 25.5μM for glyphosate and glyphosate-Cu(II), respectively. The behavioral responses indicated that exposure of D. magna to mixtures of glyphosate and Cu(II) attenuated acute metal toxicity but increased apparent glyphosate toxicity due to complexation with Cu(II). The study suggests that glyphosate is a likely mediator of aquatic metal toxicity, and that video tracking provides an opportunity for quantitative studies of sublethal effects of pesticide complexes. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Toxicity of cypermethrin to Daphnia magna HB

    Institute of Scientific and Technical Information of China (English)

    SHENG Xiu-mei; XIONG Li; WU Zhen-bin; TANG Hong-feng; LIU Tao; WANG Yuan

    2004-01-01

    The acute toxic effect of the pesticide cypermethrin to Daphnia magna HB was examined. D. magna HB was exposed to cypermethrin at concentrations of 0, 1, 3, 5, 7, and 9 mg/L for 24 h. Data showed that the 24 h-LC50 of cypermthrin on D. magna HB was 4.81 mg/L. In contrast, the 24 h-LC50 of K2Cr2O7(the national standard toxicant) to Daphnia magna was 0.38 mg/L in the current study. Results indicated that the Daphnia magna was very sensitive to pesticides. In addition, the effects of the culture condition(such as hardness, temperature and DO etc.) on Daphnia magna HB was also studied.

  4. CRISPR/Cas-mediated targeted mutagenesis in Daphnia magna.

    Directory of Open Access Journals (Sweden)

    Takashi Nakanishi

    Full Text Available The water flea Daphnia magna has been used as an animal model in ecology, evolution, and environmental sciences. Thanks to the recent progress in Daphnia genomics, genetic information such as the draft genome sequence and expressed sequence tags (ESTs is now available. To investigate the relationship between phenotypes and the available genetic information about Daphnia, some gene manipulation methods have been developed. However, a technique to induce targeted mutagenesis into Daphnia genome remains elusive. To overcome this problem, we focused on an emerging genome editing technique mediated by the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas system to introduce genomic mutations. In this study, we targeted a functionally conserved regulator of eye development, the eyeless gene in D. magna. When we injected Cas9 mRNAs and eyeless-targeting guide RNAs into eggs, 18-47% of the survived juveniles exhibited abnormal eye morphology. After maturation, up to 8.2% of the adults produced progenies with deformed eyes, which carried mutations in the eyeless loci. These results showed that CRISPR/Cas system could introduce heritable mutations into the endogenous eyeless gene in D. magna. This is the first report of a targeted gene knockout technique in Daphnia and will be useful in uncovering Daphnia gene functions.

  5. CRISPR/Cas-mediated targeted mutagenesis in Daphnia magna.

    Science.gov (United States)

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

    2014-01-01

    The water flea Daphnia magna has been used as an animal model in ecology, evolution, and environmental sciences. Thanks to the recent progress in Daphnia genomics, genetic information such as the draft genome sequence and expressed sequence tags (ESTs) is now available. To investigate the relationship between phenotypes and the available genetic information about Daphnia, some gene manipulation methods have been developed. However, a technique to induce targeted mutagenesis into Daphnia genome remains elusive. To overcome this problem, we focused on an emerging genome editing technique mediated by the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system to introduce genomic mutations. In this study, we targeted a functionally conserved regulator of eye development, the eyeless gene in D. magna. When we injected Cas9 mRNAs and eyeless-targeting guide RNAs into eggs, 18-47% of the survived juveniles exhibited abnormal eye morphology. After maturation, up to 8.2% of the adults produced progenies with deformed eyes, which carried mutations in the eyeless loci. These results showed that CRISPR/Cas system could introduce heritable mutations into the endogenous eyeless gene in D. magna. This is the first report of a targeted gene knockout technique in Daphnia and will be useful in uncovering Daphnia gene functions.

  6. Ecotoxicity tests based on phototactic behaviour in Daphnia magna; Saggi di ecotossicita` con Daphnia magna basati sul comportamento fototattico

    Energy Technology Data Exchange (ETDEWEB)

    Dojmi di Delupis, Gianluigi [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Comparata ed Ecotossicologia

    1997-03-01

    Zooplankton behaviour depending on light, such as phototaxis, is important, mainly in terms of its ecological significance, as, for example, in the role of phototaxis in the diurnal vertical migration of Daphnia magna, and its possible involvement in predator-prey relations. In Daphnia magna chemicals were found to induce roughly three types of phototaxis alteration: depression, enhancement and sign change. These phenomena are based on mechanisms that require further investigation. In spite of the complex photobehaviour of Daphnia magna and the scarce knowledge of toxic effects, it was possible to set up rapid and easy ecotoxicity tests by fixing certain experimental conditions.

  7. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Multigenerational effects of carbendazim in Daphnia magna.

    Science.gov (United States)

    Silva, Ana Rita R; Cardoso, Diogo N; Cruz, Andreia; Pestana, João L T; Mendo, Sónia; Soares, Amadeu M V M; Loureiro, Susana

    2017-02-01

    Carbendazim is a fungicide largely used in agriculture as a plant protection product. As a result of agricultural runoffs, drainage, and leaching, it reaches surface waters at concentrations possibly hazardous to aquatic communities. Because of potential and continuous release of carbendazim to aquatic systems, long-term exposure to aquatic organisms should be addressed. To fill the knowledge gap, the present study evaluated the responses of multiple generations of Daphnia magna (clone K6) to an environmentally relevant concentration of carbendazim (5 μg/L). Twelve successive generations were evaluated, and the effects in these offspring were compared with those from a control population. Neonates' fitness was assessed through immobilization, reproduction, and feeding activity tests, along with the comet assay for in vivo DNA damage evaluation. Recovery from long-term exposure was also assessed. In the F5 generation, the results revealed that when daphnids were re-exposed to carbendazim, DNA damage was higher in daphnids continuously exposed to carbendazim than those from clean medium. After daphnids were moved to a clean medium, a low recovery potential was observed for DNA damage. Daphnids exposed continuously for 6 generations (F6) to carbendazim displayed an increase in feeding rates when re-exposed to carbendazim compared with F6 daphnids reared in clean medium. Continuous exposure of daphnids to carbendazim induced a significant increase in DNA damage from the F0 to the F12 generation. Deleterious effects of the multigenerational exposure to carbendazim were more prominent at a subcellular level (DNA damage) compared with the individual level. Environ Toxicol Chem 2017;36:383-394. © 2016 SETAC. © 2016 SETAC.

  9. Small scale mass culture of Daphnia magna Straus

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Acute and chronic toxicity of veterinary antibiotics to Daphnia magna

    DEFF Research Database (Denmark)

    Wollenberger, Leah; Halling-Sørensen, B.; Kusk, Kresten Ole

    2000-01-01

    The acute and chronic toxicity of nine antibiotics used both therapeutically and as growth promoters in intensive farming was investigated on the freshwater crustacean Daphnia magna. The effect of the antibiotics metronidazole (M), olaquindox (OL), oxolinic acid (OA), oxytetracycline (OTC), strep...

  11. Evaluation of Daphnia magna as an indicator of Toxicity and ...

    African Journals Online (AJOL)

    Evaluation of Daphnia magna as an indicator of Toxicity and Treatment efficacy ... Journal of Applied Sciences and Environmental Management ... suggests that improvement of the toxicological quality of wastewater could be linked to ... a valuable model for bio- monitoring of water pollution and for evaluation of the toxicity ...

  12. Uptake and depuration of gold nanoparticles in Daphnia magna

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Kern, Kristina; Hjorth, Rune

    2014-01-01

    This study presents a series of short-term studies (total duration 48 h) of uptake and depuration of engineered nanoparticles (ENP) in neonate Daphnia magna. Gold nanoparticles (Au NP) were used to study the influence of size, stabilizing agent and feeding on uptake and depuration kinetics...

  13. Uptake and depuration of gold nanoparticles in Daphnia magna

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Kern, Kristina; Hjorth, Rune

    2014-01-01

    This study presents a series of short-term studies (total duration 48 h) of uptake and depuration of engineered nanoparticles (ENP) in neonate Daphnia magna. Gold nanoparticles (Au NP) were used to study the influence of size, stabilizing agent and feeding on uptake and depuration kinetics...

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

    Science.gov (United States)

    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.

  15. Medical-biological aspects of radiation effects in Daphnia magna

    Science.gov (United States)

    Sarapultseva, E.; Uskalova, D.; Savina, N.; Ustenko, K.

    2017-01-01

    We have shown that γ-irradiation at doses of 100 and 1000 mGy significantly compromised fecundity and reproductive success of the directly exposed D. magna. These effects were also observed among the non-exposed first-generation progeny of irradiated parents, thus implying the manifestation of transgenerational effects in Daphnia. We have also shown that compromised viability of irradiated D. magna can be attributed cytotoxic effects of irradiation. It would therefore appear that the compromised viability may be attributed to the cytotoxic effects resulted from epigenetic changes affecting some metabolic pathways involved in detoxification of free-radicals. Additionally we have analyzed more distant progeny of irradiated at doses of 10, 100 and 1000 mGy Daphnia. Our data demonstrated that multicellular crustacean D. magna represent a very useful experimental model for analyse of long-term effects of ionising radiation at the organismal level.

  16. Ecotoxicological testing of gas oils (daphnia magna test)

    Energy Technology Data Exchange (ETDEWEB)

    Altmann, B.R.; Mueller, J.; Wenzel, A.; Hensel, R.

    2002-02-01

    The Water Accomodated Fractions WAF of 4 diesel fuels no. 2 and 4 domestic heating fuels no. 2 of differing origin were analysed on their effect on the mobility of the freshwater crustacean Daphnia Magna. Five loadings per test substance were tested. After an exposition period of 24 h a relationship between loading rates of the WAF and immobility was found for 3 samples, while after 48 h this was observed for all samples. WAF-generation and gas oil data were documented. (orig.) [German] Von 4 Dieselkraftstoff-Gasoelen und 4 Heizoel-Gasoelen EL wurden die Water Accomodated Fractions WAF auf ihre immobilisierende Wirkung auf den Wasserfloh Daphnia Magna untersucht. Von jeder Probe wurden fuenf unterschiedliche Dosierraten geprueft. Nach einer Expositionszeit von 24 Stunden zeigte sich bei 3 Proben und nach 48 Stunden bei allen Proben eine Beziehung zwischen der Dosierrate der Probe und der Immobilitaet. Die Herstellung der WAF und die Daten der Gasoele wurden dokumentiert. (orig.)

  17. Ecotoxicological testing of gas oils (daphnia magna test)

    Energy Technology Data Exchange (ETDEWEB)

    Altmann, B.R.; Mueller, J.; Wenzel, A.; Hensel, R.

    2002-02-01

    The Water Accomodated Fractions WAF of 4 diesel fuels no. 2 and 4 domestic heating fuels no. 2 of differing origin were analysed on their effect on the mobility of the freshwater crustacean Daphnia Magna. Five loadings per test substance were tested. After an exposition period of 24 h a relationship between loading rates of the WAF and immobility was found for 3 samples, while after 48 h this was observed for all samples. WAF-generation and gas oil data were documented. (orig.) [German] Von 4 Dieselkraftstoff-Gasoelen und 4 Heizoel-Gasoelen EL wurden die Water Accomodated Fractions WAF auf ihre immobilisierende Wirkung auf den Wasserfloh Daphnia Magna untersucht. Von jeder Probe wurden fuenf unterschiedliche Dosierraten geprueft. Nach einer Expositionszeit von 24 Stunden zeigte sich bei 3 Proben und nach 48 Stunden bei allen Proben eine Beziehung zwischen der Dosierrate der Probe und der Immobilitaet. Die Herstellung der WAF und die Daten der Gasoele wurden dokumentiert. (orig.)

  18. Annotation of the Daphnia magna nuclear receptors: comparison to Daphnia pulex.

    Science.gov (United States)

    Litoff, Elizabeth J; Garriott, Travis E; Ginjupalli, Gautam K; Butler, LaToya; Gay, Claudy; Scott, Kiandra; Baldwin, William S

    2014-11-15

    Most nuclear receptors (NRs) are ligand-dependent transcription factors crucial in homeostatic physiological responses or environmental responses. We annotated the Daphnia magna NRs and compared them to Daphnia pulex and other species, primarily through phylogenetic analysis. Daphnia species contain 26 NRs spanning all seven gene subfamilies. Thirteen of the 26 receptors found in Daphnia species phylogenetically segregate into the NR1 subfamily, primarily involved in energy metabolism and resource allocation. Some of the Daphnia NRs, such as RXR, HR96, and E75 show strong conservation between D. magna and D. pulex. Other receptors, such as EcRb, THRL-11 and RARL-10 have diverged considerably and therefore may show different functions in the two species. Curiously, there is an inverse association between the number of NR splice variants and conservation of the LBD. Overall, D. pulex and D. magna possess the same NRs; however not all of the NRs demonstrate high conservation indicating the potential for a divergence of function. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Demographic responses of Daphnia magna fed transgenic Bt-maize

    OpenAIRE

    2009-01-01

    The food/feed quality of a variety of genetically modified (GM) maize expressing Cry1Ab Bt-toxin was tested over the life-cycle of Daphnia magna, an arthropod commonly used as model organism in ecotoxicological studies. Demographic responses were compared between animals fed GM or unmodified (UM) near isogenic maize, with and without the addition of predator smell. Age-specific data on survival and birth rates were integrated and analysed using life tables and Leslie matrices. Survival, fecun...

  20. Toxicity of perfluorononanoic acid and perfluorooctane sulfonate to Daphnia magna

    Institute of Scientific and Technical Information of China (English)

    Guang-hua Lu; Jian-chao Liu; Li-sha Sun; Lu-jin Yuan

    2015-01-01

    In order to study toxicological effects of perfluorononanoic acid (PFNA), perfluorooctane sulfonate (PFOS), and their mixtures (PFNA/PFOS) on Daphnia magna (D. magna), a suite of comprehensive toxicity tests were conducted, including a 48-h acute toxicity test, a 21-day chronic test, a feeding experiment, and a biomarker assay. D. magna were exposed to aqueous solutions of PFNA and PFOS (alone and in combination) at concentrations ranging from 0.008 to 5 mg/L. The survival, growth, and reproduction of D. magna were monitored over a 21-day life cycle. The biomarkers, including acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT) activities, were determined after seven days of exposure. PFOS was more toxic than PFNA based on the results of the acute toxicity test. Perfluorinated compounds (PFCs) inhibited both growth and reproduction of D. magna during the testing period. The ingestion rates and the biomarkers, including AChE, SOD, and CAT activities, were significantly inhibited by PFCs in most cases. Moreover, the combined effects related to the growth and reproduction showed the antagonistic effects of PFCs.

  1. Toxicity of perfluorononanoic acid and perfluorooctane sulfonate to Daphnia magna

    Directory of Open Access Journals (Sweden)

    Guang-hua LU

    2015-01-01

    Full Text Available In order to study toxicological effects of perfluorononanoic acid (PFNA, perfluorooctane sulfonate (PFOS, and their mixtures (PFNA/PFOS on Daphnia magna (D. magna, a suite of comprehensive toxicity tests were conducted, including a 48-hour acute toxicity test, a 21-day chronic test, a feeding experiment, and a biomarker assay. D. magna were exposed to aqueous solutions of PFNA and PFOS (alone and in combination at concentrations ranging from 0.008 to 5 mg/L. The survival, growth, and reproduction of D. magna were monitored over a 21-day life cycle. The biomarkers, including acetylcholinesterase (AChE, superoxide dismutase (SOD, and catalase (CAT activities, were determined after seven days of exposure. PFOS was more toxic than PFNA based on the results of the acute toxicity test. Perfluorinated compounds (PFCs inhibited both growth and reproduction of D. magna during the testing period. The ingestion rates and the biomarkers, including AChE, SOD, and CAT activities, were significantly inhibited by PFCs in most cases. Moreover, the combined effects related to the growth and reproduction showed the antagonistic effects of PFCs.

  2. Toxicity Evaluation of Wastewater Treatment Plant Effluents Using Daphnia magna

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    H Movahedian, B Bina, GH Asghari

    2005-04-01

    Full Text Available Toxicity evaluation is an important parameter in wastewater quality monitoring as it provides the complete response of test organisms to all compounds in wastewater. The water flea Daphnia magna straus is the most commonly used zooplankton in toxicological tests. The objective of this study was to evaluate the acute toxicity of effluents from different units of Isfahan Wastewater Treatment Plant (IWTP. The samples were taken from four different physical and biological units. The acute toxicity tests were determined using Daphnia magna. The immobility of Daphnia was determined after 48h. Toxicity results showed that 48h-LC50 and ATU values for raw wastewater were 30% (v/v and 3.33, respectively. It was also found that LC50 values after 48 h for preliminary, primary, and secondary effluents were 32%, 52% and 85% (v/v, respectively. The ATU values for these effluents were 3.1, 1.9, and 1.8, correspondingly. The efficiency levels of preliminary, primary, and secondary units for removal of toxicity were found as 6%, 38.9% and 8%, in that order. Overall, the present investigation indicated that toxicity removal by up to 50% might be achieved in IWPT. Based on the obtained results and regarding the improvement of water quality standards, coupled with public expectations in Iran, it is necessary to consider more stringent water quality policies for regular monitoring and toxicity assessment.

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

    Science.gov (United States)

    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.

  4. Spectral SAR Ecotoxicology of Ionic Liquids: The Daphnia magna Case

    Directory of Open Access Journals (Sweden)

    Mihai V. Putz

    2007-01-01

    Full Text Available Aiming to provide a unified theory of ionic liquids ecotoxicity, the recent spectral structure activity relationship (S-SAR algorithm is employed for testing the two additive models of anionic-cationic interaction containing ionic liquid activity: the causal and the endpoint, |0+〉 and |1+〉 models, respectively. As a working system, the Daphnia magna ecotoxicity was characterized through the formulated and applied spectral chemical-ecobiological interaction principles. Specific anionic-cationic-ionic-liquid rules of interaction along the developed mechanistic hypersurface map of the main ecotoxicity paths together with the so-called resonance limitation of the standard statistical correlation analysis were revealed.

  5. Phototoxicity and chronic toxicity of methyl paraben and 1,2-hexanediol in Daphnia magna.

    Science.gov (United States)

    Lee, Jiyun; Park, Nayeon; Kho, Younglim; Lee, Kiyoung; Ji, Kyunghee

    2017-01-01

    Parabens are used as antimicrobial preservatives in consumer products. Exposure to methylparaben (MP) has been associated with adverse health outcomes, therefore, an alternative compound, 1,2-hexanediol (1,2-H), has been applied for cosmetics. In the present study, the phototoxicity of MP and 1,2-H, as well as the toxic effect caused by chronic exposure, were investigated using Daphnia magna. The 48 h acute toxicity tests with D. magna were conducted under indoor or ultraviolet (UV) light irradiation conditions, i.e., exposure to 4 h/d sunlight. Changes in the transcription of genes related to oxidative stress were determined in D. magna juveniles, to investigate the underlying mechanism of phototoxicity. The 21 d chronic toxicity tests of MP and 1,2-H were performed under indoor light irradiation. Exposure to MP under environmental level of UV light was more detrimental to D. magna. Transcripts of catalase and glutathione-S-transferase genes in D. magna was significantly increased by co-exposure to MP and UV light. After 21 d of chronic exposure to MP and 1,2-H, the reproduction no-observed effect concentrations for D. magna were 1 and >10 mg/L, respectively. The present study showed that exposure to UV could magnify the toxicity of MP on daphnids. Although acute and chronic toxicities of 1,2-H were generally lower than those of MP, its effects on other aquatic organisms should not be ignored. Further studies are needed to identify other mechanisms of MP phototoxicity.

  6. Miniaturising acute toxicity and feeding rate measurements in Daphnia magna.

    Science.gov (United States)

    Grintzalis, Konstantinos; Dai, Wenkui; Panagiotidis, Konstantinos; Belavgeni, Alexia; Viant, Mark R

    2017-05-01

    Phenotypic markers of animal health form an essential component of regulatory toxicology. Immobilisation of neonate water fleas - Daphnia magna - as a surrogate measure of their mortality following exposure to a chemical for 24-48h forms the basis of the internationally utilised OECD acute toxicity test 202. A second important marker of animal physiology and health is feeding rate, which in Daphnia is determined by measuring the algae feeding rate. Given the widespread use of OECD test 202 for acute toxicity as well as the quantification of feeding rate in toxicological studies of daphniids, significant benefits could result from miniaturising this assay. In particular, miniaturisation would use fewer animals, less media and chemicals, less laboratory space and make the tests more compatible with automation, and therefore could result in considerable time savings. Furthermore, miniaturising phenotypic markers to the ultimate level of a single animal per well would facilitate multiple measurements of other phenotypic markers, such as behavioural responses, which could be integrated at the individual level. In this study we used a wide range of exposure vessels to evaluate the impacts of systematically varying total media volume, surface to volume ratio and animal density for the acute toxicity testing of cadmium. We demonstrate that Daphnia acute toxicity tests using single animals within 24- or 48-well plates produce equivalent results as for traditional test configurations, for different chemicals. Considering algae feeding rates by Daphnia, we studied the impacts of varying algae concentration, total volume and animal density. After having demonstrated that multiwell plates can again yield equivalent test results as traditional experimental setups, we used miniaturised test vessels to show the impact of metals on the feeding activity on daphniids for both neonates and adult animals. Overall we confirm the feasibility of a multiwell approach for Daphnia toxicity

  7. TALEN-mediated homologous recombination in Daphnia magna.

    Science.gov (United States)

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

    2015-12-17

    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.

  8. Comet Assay on Daphnia magna in eco-genotoxicity testing.

    Science.gov (United States)

    Pellegri, Valerio; Gorbi, Gessica; Buschini, Annamaria

    2014-10-01

    Detection of potentially hazardous compounds in water bodies is a priority in environmental risk assessment. For the evaluation and monitoring of water quality, a series of methodologies may be applied. Among them, the worldwide used toxicity tests with organisms of the genus Daphnia is one of the most powerful. In recent years, some attempts were made to utilize Daphnia magna in genotoxicity testing as many of the new environmental contaminants are described as DNA-damaging agents in aquatic organisms. The aim of this research was to develop a highly standardized protocol of the Comet Assay adapted for D. magna, especially regarding the isolation of cells derived from the same tissue (haemolymph) from newborn organisms exposed in vivo. Several methods for haemolymph extraction and different Comet Assay parameters were compared. Electrophoretic conditions were adapted in order to obtain minimum DNA migration in cells derived from untreated organisms and, at the same time, maximum sensitivity in specimens treated with known genotoxicants (CdCl2 and H2O2). Additional tests were performed to investigate if life-history traits of the cladoceran (such as the age of adult organisms that provide newborns, the clutch size of origin, the number of generations reared in standard conditions) and the water composition as well, might influence the response of the assay. This study confirms the potential application of the Comet Assay in D. magna for assessing genotoxic loads in aqueous solution. The newly developed protocol could integrate the acute toxicity bioassay, thus expanding the possibility of using this model species in freshwater monitoring (waters, sediment and soil elutriates) and is in line with the spirit of the EU Water Framework Directive in reducing the number of bioassays that involve medium-sized species.

  9. The first-generation Daphnia magna linkage map

    Directory of Open Access Journals (Sweden)

    De Meester Luc

    2010-09-01

    Full Text Available Abstract Background Daphnia magna is a well-established model species in ecotoxicology, ecology and evolution. Several new genomics tools are presently under development for this species; among them, a linkage map is a first requirement for estimating the genetic background of phenotypic traits in quantitative trait loci (QTL studies and is also very useful in assembling the genome. It also enables comparative studies between D. magna and D. pulex, for which a linkage map already exists. Results Here we describe the first genetic linkage map of D. magna. We generated 214 F2 (intercross clonal lines as the foundation of the linkage analysis. The linkage map itself is based on 109 microsatellite markers, which produced ten major linkage groups ranging in size from 31.1 cM to 288.5 cM. The total size of this linkage map extends to 1211.6 Kosambi cM, and the average interval for the markers within linkage groups is 15.1 cM. The F2 clones can be used to map QTLs for traits that differ between the parental clones. We successfully mapped the location of two loci with infertility alleles, one inherited from the paternal clone (Iinb1 and the other from the maternal clone (Xinb3. Conclusions The D. magna linkage map presented here provides extensive coverage of the genome and a given density of markers that enable us to detect QTLs of moderate to strong effects. It is similar in size to the linkage map of D. pulex.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  13. Chronic toxicity of silver nanoparticles to Daphnia magna under different feeding conditions

    DEFF Research Database (Denmark)

    Mackevica, Aiga; Skjolding, Lars Michael; Gergs, Andre

    2015-01-01

    availability on toxicity. This was done through a series of Daphnia magna 21-day reproduction tests (OECD 211) using 30 nm citric acid stabilized AgNP aimed at studying the influence of food abundance on the reproductive toxicity of AgNP in D. magna. The experiments were carried out as static renewal tests...

  14. Effects of phosphorus-deficient diets on the carbon and phosphorus balance of Daphnia magna

    NARCIS (Netherlands)

    DeMott, W.R.; Gulati, R.D.; Siewertsen, K.

    1998-01-01

    We used laboratory growth and feeding experiments to study the balance of carbon (C) and phosphorus (P) in Daphnia magna. Daphnia were fed high-concentration mixtures of P-sufficient and P-deficient green algae (Scenedesmus acutus; molar C:P 80 and 900, respectively) or mixtures of P-deficient

  15. Phototoxic effects of titanium dioxide nanoparticles on Daphnia magna

    Science.gov (United States)

    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

  16. [Acute toxicity of different type pesticide surfactants to Daphnia magna].

    Science.gov (United States)

    Li, Xiu-huan; Li, Hua; Chen, Cheng-yu; Li, Jian-tao; Liu, Feng

    2013-08-01

    By using the standard test methods in Experimental Guideline for Environmental Safety Evaluation of Chemical Pesticide to aquatic organisms, a comparative study was conducted on the acute toxicity of 39 nonionic, 6 anionic, and 3 cationic surfactants to Daphnia magna. The acute toxicity of three cationic surfactants 1427, 1227 and C8-10 to D. magna belonged to virulent level, and the toxicity of 1427 was the highest, with the EC50 value being 0.97 x 10(-2) mg x L(-1). The acute toxicity of nonionic surfactants polyoxyethylene ether castor oil EL, Tween, and Span emulsifiers belonged to low level, but the toxicity of alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether surfactants was relatively high, of which, AEO-7 and AEO-5 displayed high toxicity, with the EC50 value being 0.82 and 0.97 mg x L(-1), respectively. In these surfactants, the more liposolubility, the higher the toxicity was. Most of the anionic surfactants were medium in toxicity, but the acute toxicity of NNO belonged to high toxicity, with the EC50 value being 0.17 mg x L(-1).

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. The water flea Daphnia magna (Crustacea, Cladocera) as a test species for screening and evaluation of chemicals with endocrine disrupting effects on crustaceans.

    Science.gov (United States)

    Tatarazako, Norihisa; Oda, Shigeto

    2007-02-01

    The water flea Daphnia magna (Crustacea, Cladocera) is a cyclical parthenogen, which can reproduce both by parthenogenesis and by sexual reproduction. With its ease of handling in the laboratory, several testing methods using D. magna exist for regulatory toxicity testing. Recently, several studies revealed that one of the major hormone groups in insects and crustaceans, juvenile hormones, are involved in the shift of reproductive mode from parthenogenesis to sexual reproduction (production of male neonates). Using offspring sex ratio as a new endpoint has made it possible to identify chemicals with juvenile hormone-like effects on crustaceans. The testing method using D. magna, in which offspring sex ratio is incorporated as a new endpoint, is now being proposed to the OECD as an enhanced version of the existing OECD Test Guideline 211: Daphnia magna reproduction test. No other clear-cut endpoint for identifying juvenile-hormone disrupting effects has ever been found in crustaceans than the induction of male neonates production in cladocerans. In this regard, it is expected that testing methods using D. magna are suitable for screening and risk assessment of chemicals with juvenile-hormone disrupting effects.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Genes mirror geography in Daphnia magna.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. The dichotomous oxyregulatory behaviour of the planktonic crustacean Daphnia magna.

    Science.gov (United States)

    Pirow, R; Buchen, I

    2004-02-01

    The dual function of appendage movement (food acquisition, ventilation) proved to be the key to explaining the peculiar oxyregulatory repertoire of the planktonic filter feeder Daphnia magna. Short-term hypoxic exposure experiments with normoxia-acclimated animals under varying food concentrations revealed a dichotomous response pattern with a compensatory tachycardia under food-free conditions and a ventilatory compensation prevailing under food-rich conditions. Food-free, normoxic conditions resulted in maximum appendage beating rates (fA) and half-maximum heart rates (fH), which restricted the scope for oxyregulation to the circulatory system. Food-rich conditions (10(5) algal cells ml(-1)), on the contrary, had a depressing effect on fA whereas fH increased to 83% of the maximum. In this physiological state, D. magna was able to respond to progressive hypoxia with a compensatory increase in ventilation. A conceptual and mathematical model was developed to analyse the efficiency of ventilatory and circulatory adjustments in improving oxygen transport to tissue. Model predictions showed that an increase in perfusion rate was most effective under both food-free and food-rich conditions in reducing the critical ambient oxygen tension (PO2crit) at which oxygen supply to the tissue started to become impeded. By contrast, a hypothetical increase in ventilation rate had almost no effect on PO2crit under food-free conditions, indicating that appendage movement is driven by nutritive rather than respiratory requirements. However, the model predicted a moderate reduction of PO2crit by hyperventilation under food-rich conditions. Since the regulatory scope for an adjustment in fH was found to be limited in D. magna under these conditions, the increase in ventilation rate is the means of choice for a fed animal to cope with short-term, moderate reductions in ambient oxygen availability. Under long-term and more severe hypoxic conditions, however, the increase in the

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

    OpenAIRE

    Choi, Jong‐Yun; Kim, Seong‐Ki; La, Geung‐Hwan; Chang, Kwang‐Hyeon; Kim, Dong‐Kyun; Jeong, Keon‐Young; Min S. Park; Jo, Hyunbin; Kim, Hyun‐Woo; Jeong, Kwang‐Seuk

    2016-01-01

    Abstract 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) ...

  4. Toxic effects of chemical dispersant Corexit 9500 on water flea Daphnia magna.

    Science.gov (United States)

    Toyota, Kenji; McNabb, Nicole A; Spyropoulos, Demetri D; Iguchi, Taisen; Kohno, Satomi

    2017-02-01

    In 2010, approximately 2.1 million gallons of chemical dispersants, mainly Corexit 9500, were applied in the Gulf of Mexico to prevent the oil slick from reaching shorelines and to accelerate biodegradation of oil during the Deepwater Horizon oil spill. Recent studies have revealed toxic effects of Corexit 9500 on marine microzooplankton that play important roles in food chains in marine ecosystems. However, there is still little known about the toxic effects of Corexit 9500 on freshwater zooplankton, even though oil spills do occur in freshwater and chemical dispersants may be used in response to these spills. The cladoceran crustacean, water flea Daphnia magna, is a well-established model species for various toxicological tests, including detection of juvenile hormone-like activity in test compounds. In this study, we conducted laboratory experiments to investigate the acute and chronic toxicity of Corexit 9500 using D. magna. The acute toxicity test was conducted according to OECD TG202 and the 48 h EC50 was 1.31 ppm (CIs 0.99-1.64 ppm). The reproductive chronic toxicity test was performed following OECD TG211 ANNEX 7 and 21 days LOEC and NOEC values were 4.0 and 2.0 ppm, respectively. These results indicate that Corexit 9500 has toxic effects on daphnids, particularly during the neonatal developmental stage, which is consistent with marine zooplankton results, whereas juvenile hormone-like activity was not identified. Therefore, our findings of the adverse effects of Corexit 9500 on daphnids suggest that application of this type of chemical dispersant may have catastrophic impacts on freshwater ecosystems by disrupting the key food chain network. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Comparative toxicity of leachates from 52 textiles to Daphnia magna.

    Science.gov (United States)

    Dave, Göran; Aspegren, Pia

    2010-10-01

    The environmental aspects of textiles are very complex and include production, processing, transport, usage, and recycling. Textiles are made from a variety of materials and can contain a large number of chemicals. Chemicals are used during production of fibres, for preservation and colouring and they are released during normal wear and during washing. The aim of this study was to investigate the release to water of toxic chemicals from various textiles. Altogether 52 samples of textiles made from cotton (21), linen (4), cotton and linen (7), cellulose (3), synthetic fibres (7), cotton and synthetic fibres (8) and wool (2). Seven were eco-labelled. All textiles were cut into squares and placed into Petri dishes with 50 ml ISO test medium in a concentration series (4-256 cm(2)/50 ml) and tested for acute toxicity to Daphnia magna. Estimated EC50s were converted into weight/volume, and 48-h EC50s ranged between 182 g/L. It was not possible to detect any difference between fibre type and toxicity (ANOVA), but a significantly higher toxicity was found for printed versus unprinted cotton and cotton/linen textiles, while the opposite was found for synthetic textiles. Eco-labelled products were evenly distributed on a toxicity scale, which means that eco-labelling in its present form does not necessarily protect users or the environment from exposure to toxic chemicals. Therefore, the results from the present study suggest that bioassays and toxicity tests should become an integrated part of textile environmental quality control programs.

  6. The effects of food availability on growth and reproduction of Daphnia magna exposed to silver nanoparticles

    DEFF Research Database (Denmark)

    Mackevica, Aiga; Skjolding, Lars Michael; Gergs, A.

    The number of available studies on the acute effects of silver nanoparticles (AgNP) on aquatic organisms has increased dramatically in recent years, but there is still very limited information available on chronic effects. In this study, a series of Daphnia magna 21-days reproduction test (OECD 211......Ag/L, and the test animals were fed with green algae Pseudokirchneriella subcapitata in amounts of approximately 0.12 mgC/Daphnia/day for standard treatment or 0.36 mgC/Daphnia/day for high food availability treatment. The parameters of interest were survival, growth rate of mother animals, days to first live...

  7. Filtering capacity of Daphnia magna on sludge particles in treated wastewater.

    Science.gov (United States)

    Pau, Conxi; Serra, Teresa; Colomer, Jordi; Casamitjana, Xavier; Sala, Lluís; Kampf, Ruud

    2013-01-01

    A great challenge in water reuse is the reduction of suspended particle concentration in wastewater. In particular the reduction of the presence of small particles in suspension which cause a cloudy appearance in the water and, which also make disinfection difficult. The present study evaluates the filtering capacity of a population of Cladodera (Daphnia magna) in secondary effluents from a wastewater plant. The study was performed in both a mesocosm and the laboratory, in an effort to compare the grazing on sludge particles by Daphnia versus the settling rate of those sludge particles. The particle volume concentration of small particles (with a diameter below 30 μm) was used to evaluate the efficiency of the proposed biotreatment system for small particles. Both laboratory and mesocosm results showed that the suspended particle volume concentration decreased with time due to the Daphnia filtration, with the highest reduction in experiments carried out with the highest Daphnia concentration. In the mesocosm experiments, the Daphnia diameter was also found to play an important role, with an allometric relationship between the filtering rate of Daphnia and the Daphnia nondimensional diameter. In laboratory experiments, the effect of D. magna in the suspended concentration of small particles was in the range of 10.1-29.4%, according to the range of Daphnia concentration of 10-50 ind/l. For laboratory experiments, sedimentation was responsible for 62.2% of the suspended particle concentration reduction. For the mesocosm experiments, the reduction in the particle concentration attributed to the Daphnia filtration ranged between 2.5 and 39%, corresponding to Daphnia concentrations of between 5 and 100 ind/l (i.e. biovolumes of 8-60 ind/l). Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Food mediated life history strategies in Daphnia magna : their relevance to ecotoxicological evaluations

    NARCIS (Netherlands)

    Enserink, E.L.

    1995-01-01

    The waterflea Daphnia magna is a widely used test organism in ecotoxicological studies. Acute and chronic laboratory tests yield basic information for the development of water quality standards, assessment of potential hazards of (new) chemicals, waste water licences and

  9. Food mediated life history strategies in Daphnia magna: their relevance to ecotoxicological evaluations.

    NARCIS (Netherlands)

    Enserink, E.L.

    1995-01-01

    The waterflea Daphnia magna is a widely used test organism in ecotoxicological studies. Acute and chronic laboratory tests yield basic information for the development of water quality standards, assessment of potential hazards of (new) chemicals, waste water licences and sanitation measures for cont

  10. Differences in orientation behaviour underlie interclonal differences in phototaxis in Daphnia magna

    NARCIS (Netherlands)

    Van Gool, E.

    1999-01-01

    I studied the orientation direction of the body and the eye in response to contrasts in Daphnia magna. The orientation of the body was studied on pinned, but freely rotating daphnids, and on freely swimming daphnids. The orientation direction of the eye was studied on daphnids with a fixed position

  11. Acute and chronic toxicity of short chained perfluoroalkyl substances to Daphnia magna

    NARCIS (Netherlands)

    Barmentlo, S.H.; Stel, J.M.; van Doorn, M.; Eschauzier, C.; de Voogt, P.; Kraak, M.H.S.

    2015-01-01

    The aim of this study was to evaluate the aquatic toxicity of a C4-C6 chemistry based fluoroalkylated polymer and the perfluoroalkyl carboxylic acids, PFBA, PFHxA and PFOA to Daphnia magna. The acute toxicity decreased with decreasing carbon chain length, but the polymer did not show a dose related

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

    Science.gov (United States)

    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...

  13. Acute toxicity of copper oxide nanoparticles to Daphnia magna under different test conditions

    DEFF Research Database (Denmark)

    Thit, Amalie; Huggins, Krista; Selck, Henriette

    2017-01-01

    The acute toxicity of monodispersed 6 nm and Daphnia magna was assessed using 48 h immobilization tests. CuSO4 was used as a reference. Four different exposure conditions were tested, to study whether the toxicity of the nanoparticle...

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

    NARCIS (Netherlands)

    Pieters, B.J.; Liess, M.

    2006-01-01

    Abstract: 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 w

  15. Bioavailability and effect of pirimicarb on Daphnia magna in a laboratory freshwater/sediment system

    DEFF Research Database (Denmark)

    Kusk, K.O.

    1996-01-01

    In tests with newborn and one-week-old Daphnia magna, 48-h EC(50) values of 21-24 mu g/L and 16 mu g/L pirimicarb, respectively, were found. Older animals thus were as sensitive to pirimicarb as newborn animals. In an experiment with sediment included in the test system, all mother animals surviv...

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

    Science.gov (United States)

    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

  17. Toxicity of aqueous C70-gallic acid suspension in Daphnia magna.

    Science.gov (United States)

    Seda, Brandon C; Ke, Pu-Chun; Mount, Andrew S; Klaine, Stephen J

    2012-01-01

    The present study assessed the toxic effects of stable aqueous colloidal suspensions of gallic-acid-stabilized C(70) fullerene on Daphnia magna. The suspensions were stabilized through noncovalent surface modification with gallic acid. In addition to whole-organism responses, changes in antioxidative processes in D. magna were quantified. Acute toxicity was observed with 96LC50 for C(70) -gallic acid of 0.4 ± 0.1 mg/L C(70) . Daphnia magna fecundity was significantly reduced in 21-d bioassays at C(70) -gallic aqcid concentrations below quantifiable limits. Antioxidant enzyme activities of glutathione peroxidase and superoxide dismutase as well as lipid peroxidation suggested that exposed organisms experienced oxidative stress. Microscopic techniques used to determine cellular toxicity via apoptosis proved unsuccessful.

  18. Male meiosis in Crustacea: synapsis, recombination, epigenetics and fertility in Daphnia magna.

    Science.gov (United States)

    Gómez, Rocío; Van Damme, Kay; Gosálvez, Jaime; Morán, Eugenio Sánchez; Colbourne, John K

    2016-09-01

    We present the first detailed cytological study of male meiosis in Daphnia (Crustacea: Branchiopoda: Cladocera)-an aquatic microcrustacean with a cyclical parthenogenetic life cycle. Using immunostaining of the testes in Daphnia magna for baseline knowledge, we characterized the different stages of meiotic division and spermiogenesis in relation to the distribution of proteins involved in synapsis, early recombination events and sister chromatid cohesion. We also studied post-translational histone modifications in male spermatocytes, in relation to the dynamic chromatin progression of meiosis. Finally, we applied a DNA fragmentation test to measure sperm quality of D. magna, with respect to levels of inbreeding. As a proxy for fertility, this technique may be used to assess the reproductive health of a sentinel species of aquatic ecosystems. Daphnia proves to be a model species for comparative studies of meiosis that is poised to improve our understanding of the cytological basis of sexual and asexual reproduction.

  19. Enhancement of toxic effects of phenanthrene to Daphnia magna due to the presence of suspended sediment.

    Science.gov (United States)

    Zhang, Xiaotian; Xia, Xinghui; Dong, Jianwei; Bao, Yimeng; Li, Husheng

    2014-06-01

    In the present work, the influences of suspended sediment (SPS) on the toxic effects of phenanthrene (PHE), one kind of polycyclic aromatic hydrocarbons, to Daphnia magna was studied using a dialysis bag simulation system, which equalized the freely dissolved concentration of PHE between outside the dialysis bag in the presence of SPS and inside the dialysis bag in the absence of SPS. The immobilization and total superoxide dismutase (T-SOD) activity of Daphnia magna caused by PHE (0-0.8 mg L(-1)) were investigated under the influence of different SPS concentrations (0, 1, 3, 5 g L(-1)) during a 96 h-exposure. The results showed that, compared to the absence of SPS, the presence of SPS (1-5 g L(-1)) increased the immobilization of Daphnia magna by 1.6-2.7 times when the freely dissolved concentration of PHE was identical in both systems. The inhibition of T-SOD activity of Daphnia magna by PHE was significantly greater in the presence of SPS than in the absence of SPS (pDaphnia magna. The bioavailable fraction of PHE sorbed on SPS ranged from 10.1% to 22.7%, and the contribution of PHE sorbed on SPS to the immobilization caused by total PHE in the exposure system increased with SPS concentration, with the contribution ratio increasing from 36.7% to 57.7% when SPS concentration increased from 1 to 5 g L(-1). This study suggests that only considering the concentrations of hydrophobic organic compounds in the water phase may underestimate their toxicity; and the hydrophobic organic compounds sorbed on SPS should not be ignored in assessment of water quality and the establishment of water quality standard in the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Titanium dioxide nanoparticles increase sensitivity in the next generation of the water flea Daphnia magna.

    Directory of Open Access Journals (Sweden)

    Mirco Bundschuh

    Full Text Available The nanoparticle industry is expected to become a trillion dollar business in the near future. Therefore, the unintentional introduction of nanoparticles into the environment is increasingly likely. However, currently applied risk-assessment practices require further adaptation to accommodate the intrinsic nature of engineered nanoparticles. Combining a chronic flow-through exposure system with subsequent acute toxicity tests for the standard test organism Daphnia magna, we found that juvenile offspring of adults that were previously exposed to titanium dioxide nanoparticles exhibit a significantly increased sensitivity to titanium dioxide nanoparticles compared with the offspring of unexposed adults, as displayed by lower 96 h-EC(50 values. This observation is particularly remarkable because adults exhibited no differences among treatments in terms of typically assessed endpoints, such as sensitivity, number of offspring, or energy reserves. Hence, the present study suggests that ecotoxicological research requires further development to include the assessment of the environmental risks of nanoparticles for the next and hence not directly exposed generation, which is currently not included in standard test protocols.

  1. Titanium dioxide nanoparticles increase sensitivity in the next generation of the water flea Daphnia magna.

    Science.gov (United States)

    Bundschuh, Mirco; Seitz, Frank; Rosenfeldt, Ricki R; Schulz, Ralf

    2012-01-01

    The nanoparticle industry is expected to become a trillion dollar business in the near future. Therefore, the unintentional introduction of nanoparticles into the environment is increasingly likely. However, currently applied risk-assessment practices require further adaptation to accommodate the intrinsic nature of engineered nanoparticles. Combining a chronic flow-through exposure system with subsequent acute toxicity tests for the standard test organism Daphnia magna, we found that juvenile offspring of adults that were previously exposed to titanium dioxide nanoparticles exhibit a significantly increased sensitivity to titanium dioxide nanoparticles compared with the offspring of unexposed adults, as displayed by lower 96 h-EC(50) values. This observation is particularly remarkable because adults exhibited no differences among treatments in terms of typically assessed endpoints, such as sensitivity, number of offspring, or energy reserves. Hence, the present study suggests that ecotoxicological research requires further development to include the assessment of the environmental risks of nanoparticles for the next and hence not directly exposed generation, which is currently not included in standard test protocols.

  2. The screening of chemicals for juvenoid-related endocrine activity using the water flea Daphnia magna.

    Science.gov (United States)

    Wang, Helen Ying; Olmstead, Allen W; Li, Hong; Leblanc, Gerald A

    2005-09-10

    U.S. Environmental Protection Agency is charged with developing a screening and testing paradigm for detecting endocrine toxicity of chemicals that are subject to regulation under the Food Quality Protection and the Safe Drinking Water Acts. In this study, we developed and evaluated a screening assay that could be employed to detect juvenoid-related endocrine-modulating activity in an invertebrate species. Juvenoid activity, anti-juvenoid activity, and juvenoid potentiator activity of chemicals was assessed using the water flea Daphnia magna. Male sex determination is under the regulatory control of juvenoid hormone, presumably methyl farnesoate, and this endpoint was used to detect juvenoid modulating activity of chemicals. Eighteen chemicals were evaluated for juvenoid agonist activity. Positive responses were detected with the juvenoid hormones methyl farnesoate and juvenile hormone III along with the insect growth regulating insecticides pyriproxyfen, fenoxycarb, and methoprene. Weak juvenoid activity also was detected with the cyclodiene insecticide dieldrin. Assays performed repetitively with compounds that gave either strong positive, weak positive, or negative response were 100% consistent indicating that the assay is not prone to false positive or negative responses. Five candidate chemicals were evaluated for anti-juvenoid activity and none registered positive. Four chemicals (all trans-retinoic acid, methoprene, kinoprene, bisphenol A) also were evaluated for their ability to potentiate the activity of methyl farnesoate. All registered positive. Results demonstrate that an in vivo assay with a crustacean species customarily employed in toxicity testing can be used to effectively screen chemicals for juvenoid-modulating activity.

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

    Science.gov (United States)

    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 water bodies.

  4. Physiology of immunity in the water flea Daphnia magna: environmental and genetic aspects of phenoloxidase activity.

    Science.gov (United States)

    Mucklow, Patrick T; Ebert, Dieter

    2003-01-01

    In an attempt to understand the ecological correlates of immunocompetence in Daphnia magna (Crustacea, Cladocera), we tested for variation in immune function in relation to feeding conditions, host conditions, and host genotype. We investigated both phenotypic (environmental dependent and condition dependent) as well as genotypic aspects of the prophenoloxidase activating system (Pro-POAS), which has been described as a key factor in invertebrate immunity. Daphnia magna is an ideal study system to disentangle phenotypic and genetic variation because females can reproduce clonally. Well-fed Daphnia showed higher phenoloxidase (PO) activity than Daphnia kept at a low food level. Wounding provoked a higher level of PO activity, indicating that the Pro-POAS was condition dependent. Further, we found clonal variation in PO activity among four clones of D. magna isolated from four different populations. The same four clones were tested for their resistance to the bacterial pathogen Pasteuria ramosa. High resistance corresponded to high PO activity. Our results suggest adaptive variation in PO activity and suggest that its expression is costly. These costs may influence the evolution of the PO activity level and the maintenance of its genotypic variation.

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

    Science.gov (United States)

    Ünlü, Ercan Selçuk; Gordon, Donna M; Telli, Murat

    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.

  6. Temperature-dependent effect of filamentous cyanobacteria on Daphnia magna life history traits

    Directory of Open Access Journals (Sweden)

    Piotr DAWIDOWICZ

    2011-08-01

    Full Text Available Filamentous cyanobacteria are unsuitable food for Daphnia due to their poor manageability, poor nutritional value and, in some cases, toxicity. As the strength of harmful effects of cyanobacteria on filter-feeding zooplankton is temperature dependent, the global warming scenarios for eutrophic lakes in temperate zone might include an escalated suppression of Daphnia populations caused by the presence of cyanobacterial filaments. To test this assumption, we conducted life-table experiments with four clones of Daphnia magna fed either a green alga Scenedesmus obliquus or a non-toxic strain of filamentous cyanobacteria Cylindrospermopsis raciborskii in two temperatures (20 °C and 24 °C. Key life history parameters of Daphnia, i.e., age and size at first reproduction, fecundity, and individual growth rate, were measured. Both food and temperature significantly affected Daphnia performance, however, the effect of interaction of these two factors was ambiguous and highly genotype-dependent. We conclude that the temperature increase within the studied range will not necessarily strengthen the suppression of Daphnia growth by filamentous cyanobacteria, but may affect clonal selection within population of Daphnia, thus possibly triggering microevolutionary changes within affected populations.

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

    Science.gov (United States)

    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.

  8. Toxicity of Nanoscale CuO and ZnO to Daphnia magna

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hai-zhou; LU Guang-hua; XIA Jun; JIN Shao-ge

    2012-01-01

    The potential effects of nanoscale CuO(nCuO),nanoscale ZnO(nZnO)and their mixtures on Daphnia magna were investigated,including 48-h acute toxicity and 21-d chronic toxicity tests as well as a feeding experiment.The results of acute toxicity show that nCuO/nZnO mixture was the most toxic followed by nCuO and nZnO.The nanoparticles(NPs)inhibited both the growth and reproduction of Daphnia magna during the testing period.Concentration dependence was apparent in all the cases and the intrinsic rate of natural increase was confirmed to be a very sensitive parameter to NPs exposure.Binary mixture appeared to be more toxic than the corresponding individual exposures at most cases except for the feeding behavior.

  9. Toxicity of chiral pesticide Rac-metalaxyl and R-metalaxyl to Daphnia magna.

    Science.gov (United States)

    Chen, Shengwen; Liu, Weiping

    2008-12-01

    Chirality in pesticides has become a challenge because of enantiomers' different toxicities to non-target organisms. Acute and chronic toxicities of Rac-metalaxyl and R-metalaxyl to Daphnia magna were determined and compared. The 48-h LC50 for Rac- and R-metalaxyl to Daphnia magna were 51.5 and 41.9 mg/L. In a 14-day chronic test, the lowest-observed-effective concentration (LOEC) and no-observed-effective concentration (NOEC) of Rac-metalaxyl were 2 and 1 mg/L, respectively, whereas those of R-metalaxyl were 1 and 0.1 mg/L. Body length, days-to-first-brood and number of broods per female were significantly (p metalaxyl at >1.0 mg/L, but affected by Rac-metalaxyl at >or=2.0 mg/L.

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

    Science.gov (United States)

    Meinertz, Jeffery R.; Schreier, Theresa M.; Bernardy, Jeffry A.; Franz, Jeanne L.

    2011-01-01

    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 μg/L for 21 days or to ET concentrations about 40 times the maximum reported environmental concentration of 6 μg/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 μg/L and for ET was 248 μg/L.

  11. Bioaccumulation of perfluoroalkyl substances by Daphnia magna in water with different types and concentrations of protein.

    Science.gov (United States)

    Xia, Xinghui; Rabearisoa, Andry H; Jiang, Xiaoman; Dai, Zhineng

    2013-10-01

    Perfluoroalkyl substances (PFASs) are sometimes regarded as proteinophilic compounds, however, there is no research report about the effect of environmental protein on the bioaccumulation of PFASs in waters. In the present study we investigated influences of protein on the bioaccumulation of six kinds of PFASs by Daphnia magna in water; it included perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Two types of protein including bovine albumin from animal and soy peptone from plant were compared and the effects of protein concentration were investigated. Both types of protein at high concentrations (10 and 20 mg L(-1)) suppressed the bioaccumulation of PFASs. When protein concentration increased from 0 to 20 mg L(-1), the decreasing ratios of the PFAS body burden (35.3-52.9%) in Daphnia magna induced by bovine albumin were significantly higher than those (22.0-36.6%) by soy peptone. The dialysis bag experiment results showed that the binding of PFASs to protein followed the Freundlich isotherm, suggesting it is not a linear partitioning process but an adsorption-like process. The partition coefficients of PFASs between bovine albumin and water were higher compared to soy peptone; this resulted in higher reducing rates of freely dissolved concentrations of PFASs with increasing bovine albumin concentration, leading to a stronger suppression of PFAS bioaccumulation. However, the presence of both types of protein with a low concentration (1 mg L(-1)) enhanced the bioaccumulation of PFASs. Furthermore, the water-based bioaccumulation factor based on the freely dissolved concentrations of PFASs even increased with and the depuration rate constants of PFASs from Daphnia magna decreased with protein concentration, suggesting that protein would not only reduce the bioavailable concentrations and uptake rates of PFASs but also lower the elimination rates of PFASs in

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Daphnia magna fitness during low food supply under different water temperature and brownification scenarios

    Directory of Open Access Journals (Sweden)

    Andrea Gall

    2016-11-01

    Full Text Available Much of our current knowledge about non-limiting dietary carbon supply for herbivorous zooplankton is based on experimental evidence and typically conducted at ~1 mg C L-1 and ~20°C. Here we ask how low supply of dietary carbon affects somatic growth, reproduction, and survival of Daphnia magna and test effects of higher water temperature (+3 °C relative to ambient and brownification (3X higher than natural water color; both predicted effects of climate change during fall cooling. We predicted that even at very low carbon supply (~5µg C L-1, higher water temperature and brownification will allow D. magna to increase its fitness. Neonates (<24 h old were incubated with lake seston for 4 weeks (October-November 2013 in experimental bottles submerged in outdoor mesocosms to explore effects of warmer and darker water. Higher temperature and brownification did not significantly affect food quality, as assessed by its fatty acid composition. Daphnia exposed to both increased temperature and brownification had highest somatic growth and were the only that reproduced, and higher temperature caused the highest Daphnia survival success. These results suggest that even under low temperature and thus lower physiological activity, low food quantity is more important than its quality for D. magna fitness.

  14. Bioavailability and effect of pirimicarb on Daphnia magna in a laboratory freshwater/sediment system

    DEFF Research Database (Denmark)

    Kusk, K.O.

    1996-01-01

    In tests with newborn and one-week-old Daphnia magna, 48-h EC(50) values of 21-24 mu g/L and 16 mu g/L pirimicarb, respectively, were found. Older animals thus were as sensitive to pirimicarb as newborn animals. In an experiment with sediment included in the test system, all mother animals survived...... for 72 h at 20 mu g/L, and the number of offspring was not reduced relatively to the control. Addition of sediment thus reduced the toxicity of pirimicarb toward Daphnia magna. Pirimicarb was accumulated 12-16 times (5-7% of total) in the sediment, but the water concentrations of pirimicarb were...... not reduced significantly during the experiment, due to the small amount of sediment used. Accumulation in the sediment was found independent of the water concentration used. This was also the case with bioaccumulation in Daphnia magna, where a bioaccumulation factor of 31-37 was found on a dry weight basis...

  15. Toxaphene detoxification and acclimation in Daphnia magna: do cytochrome P-450 enzymes play a role?

    Science.gov (United States)

    Kashian, Donna R

    2004-01-01

    Toxaphene is a persistent environmental contaminant that has been shown to alter male production in Daphnia magna and to induce P-450 activity in mammals. Cytochrome P-450-mediated metabolism may lead to xenobiotic detoxification resulting in acclimation. To determine if D. magna acclimate to toxaphene via P-450 pathways, chronic and acute toxicity tests were conducted with D. magna exposed to toxaphene in the presence and absence of piperonyl butoxide (PBO), an inhibitor of cytochrome P-450 enzymes. Toxaphene exposure increased male production in acute but not chronic assays, indicating that D. magna may acclimate to chronic toxaphene exposure. Upon co-administration of toxaphene and PBO in chronic tests, D. magna exhibited a decline in growth rate, fecundity and survival. The observed toxaphene acclimation in chronic tests, along with its increased toxicity in the presence of a P-450 suppressor, suggests that P-450 enzymes may contribute to detoxification and subsequent acclimation of D. magna to chronic toxaphene exposure. Additional chronic toxicity tests indicated that toxaphene acclimation occurs between 7 and 12 days following initial exposure, at which time sex determination is no longer affected. Thus, sublethal toxaphene toxicity effects such as reproductive impairments may be detectable with acute but not chronic tests, potentially due to the upregulation of P-450 isozymes.

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

    Science.gov (United States)

    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.

  17. In vivo biodegradation of colloidal quantum dots by a freshwater invertebrate, Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Dongwook; Kim, Min Jung; Park, Chansik; Park, Jaehong [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Choi, Kyungho [Department of Environmental Health, Seoul National University, Seoul 151-742 (Korea, Republic of); Yoon, Tae Hyun, E-mail: thyoon@gmail.com [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2012-06-15

    Impacts of planktonic invertebrate, Daphnia magna, on the speciation of colloidal quantum dots (QD) were investigated using fluorescence spectromicroscopic technique. Well-dispersed {sup GA/TOPO}QD were prepared by forming a supramolecular assembly of hydrophobic {sup TOPO}QD with biomacromolecules (i.e., Gum Arabic, GA). Biological degradation of this nanomaterial was monitored by fluorescence spectromicroscopic methods. Our study confirmed the major uptake pathway of manufactured nanomaterials and in vivo biodegradation processes in a well-known toxicity test organism, D. magna. In addition, we also found that D. magna can induce significant deterioration of aquatic media by releasing fragments of partially degraded QD colloids. These biological processes may significantly change the predicted toxicities of nanomaterials in aquatic environments. Thus, we propose that the impacts of aquatic living organisms on the environmental fate of manufactured nanomaterials (MNs) should be carefully taken into account when assessing the risk of MNs to the environment and human health.

  18. The Neurophysiological Effects of Guarana and Ethanol Intake on Daphnia magna

    Directory of Open Access Journals (Sweden)

    Rebecca E. Kohn

    2009-01-01

    Full Text Available In recent years, the consumption of energy drinks and alcoholic beverages has become a prevalent habit, especially among younger generations. However, there is little scientific research surrounding the interaction of ethanol and the natural stimulant guarana, which is being utilized more frequently as the main caffeine source in energy drinks. This study utilized Daphnia magna (D. magna as a model organism to observe alterations in the functioning of the central nervous system when exposed to both ethanol and guarana in a series of time trials. As expected, ethanol significantly decreased the overall heart rate of the D. magna, while guarana increased it. In combination, the depressant effects of ethanol decreased the stimulating effects of guarana, as our results displayed a statistically significant reduction of heart rate. Therefore we propose that our findings indicated that the alcohol effects may be stronger than the effects of guarana.

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

    Science.gov (United States)

    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 (pacetylsalicylic acid induces oxidative stress and DNA damage in D. magna.

  20. Symbiotic bacteria contribute to increasing the population size of a freshwater crustacean, Daphnia magna.

    Science.gov (United States)

    Peerakietkhajorn, Saranya; Tsukada, Koji; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

    2015-04-01

    The filter-feeding crustacean Daphnia is a key organism in freshwater ecosystems. Here, we report the effect of symbiotic bacteria on ecologically important life history traits, such as population dynamics and longevity, in Daphnia magna. By disinfection of the daphniid embryos with glutaraldehyde, aposymbiotic daphniids were prepared and cultured under bacteria-free conditions. Removal of bacteria from the daphniids was monitored by quantitative polymerase chain reaction for bacterial 16S rRNA gene. The population of aposymbiotic daphniids was reduced 10-folds compared with that of the control daphniids. Importantly, re-infection with symbiotic bacteria caused daphniids to regain bacteria and increase their fecundity to the level of the control daphniids, suggesting that symbiotic bacteria regulate Daphnia fecundity. To identify the species of symbiotic bacteria, 16S rRNA genes of bacteria in daphniids were sequenced. This revealed that 50% of sequences belonged to the Limnohabitans sp. of the Betaproteobacteria class and that the diversity of bacterial taxa was relatively low. These results suggested that symbiotic bacteria have a beneficial effect on D. magna, and that aposymbiotic Daphnia are useful tools in understanding the role of symbiotic bacteria in the environmental responses and evolution of their hosts. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

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

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    Asghari Saba

    2012-04-01

    Full Text Available Abstract 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.

  2. Genomic integration and germline transmission of plasmid injected into crustacean Daphnia magna eggs.

    Directory of Open Access Journals (Sweden)

    Yasuhiko Kato

    Full Text Available The water flea, Daphnia, has been the subject of study in ecology, evolution, and environmental sciences for decades. Over the last few years, expressed sequence tags and a genome sequence have been determined. In addition, functional approaches of overexpression and gene silencing based on microinjection of RNAs into eggs have been established. However, the transient nature of these approaches prevents us from analyzing gene functions in later stages of development. To overcome this limitation, transgenesis would become a key tool. Here we report establishment of a transgenic line using microinjection of plasmid into Daphnia magna eggs. The green fluorescent protein (GFP gene fused with the D. magna histone H2B gene under the control of a promoter/enhancer region of the elongation factor 1α-1 (EF1α-1 gene, EF1α-1::H2B-GFP, was used as a reporter providing high resolution visualization of active chromatin. Transgenic lines were obtained from 0.67% of the total fertile adults that survived the injections. One of the transgenic animals, which exhibited fluorescence in the nuclei of cells during embryogenesis and oogenesis, had two copies of EF1α-1::H2B-GFP in a head-to-tail array. This is the first report of a transgenesis technique in Daphnia and, together with emerging genome sequences, will be useful for advancing knowledge of the molecular biology of Daphnia.

  3. The effect of temperature on the sensitivity of Daphnia magna to cyanobacteria is genus dependent.

    Science.gov (United States)

    Hochmuth, Jennifer D; De Schamphelaere, Karel A C

    2014-10-01

    In the present study, the authors investigated the effects of 6 different genera of cyanobacteria on multiple endpoints of Daphnia magna in a 21-d life table experiment conducted at 3 different temperatures (15 °C, 19 °C, and 23 °C). The specific aims were to test if the effect of temperature on Daphnia's sensitivity to cyanobacteria differed among different cyanobacteria and if the rank order from most to least harmful cyanobacteria to Daphnia reproduction changed or remained the same across the studied temperature range. Overall, the authors observed a decrease in harmful effects on reproduction with increasing temperature for Microcystis, Nodularia, and Aphanizomenon, and an increase in harmful effects with increasing temperature for Anabaena and Oscillatoria. No effect of temperature was observed on Daphnia sensitivity to Cylindrospermopsis. Harmful effects of Microcystis and Nodularia on reproduction appear to be mirrored by a decrease in length. On the other hand, harmful effects of Anabaena, Aphanizomenon, and Oscillatoria on reproduction were correlated with a decrease in intrinsic rate of natural increase, which was matched by a later onset of reproduction in exposures to Oscillatoria. In addition, the results suggest that the cyanobacteria rank order of harmfulness may change with temperature. Higher temperatures may increase the sensitivity of D. magna to the presence of some cyanobacteria (Anabaena and Oscillatoria) in their diet, whereas the harmful effects of others (Microcystis, Nodularia, and Aphanizomenon) may be reduced by higher temperatures.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Optimization of mRNA design for protein expression in the crustacean Daphnia magna.

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

    2014-08-01

    The water flea Daphnia is a new model organism for ecological, evolutionary, and toxicological genomics. Detailed functional analysis of genes newly discovered through genomic approaches often requires overexpression of the identified protein. In the present study, we report the microinjection of in vitro-synthesized RNAs into the eggs as a method for overexpressing ubiquitous proteins in Daphnia magna. We injected a 1.3-kb mRNA that coded for the red fluorescent protein (DsRed2) flanked by UTRs from the ubiquitously expressed elongation factor 1α-1 (EF1α-1) into D. magna embryos. DsRed2 fluorescence in the embryos was measured 24 h after microinjection. Unexpectedly, the reporter RNA containing the 522-bp full-length EF1α-1 3' UTR failed to induce fluorescence. To assess reporter expression, the length of the 3' UTR that potentially contained negative regulatory elements of protein expression, including AU-rich regions and Musashi binding elements, was serially reduced from the 3' end. Assessing all injected RNA alternatives, mRNA containing the first 60 bp of the 3' UTR gave rise to the highest fluorescence, 14 times the Daphnia auto-fluorescence. In contrast, mRNA lacking the entire 3' UTR hardly induced any change in fluorescence intensity. This is the first evaluation of UTRs of mRNAs delivered into Daphnia embryos by microinjection for overexpressing proteins. The mRNA with truncated 3' UTRs of Daphnia EF1α-1 will be useful not only for gain-of-function analyses but also for labeling proteins and organelles with fluorescent proteins in Daphnia.

  6. Gene expression profiling of three different stressors in the water flea Daphnia magna.

    Science.gov (United States)

    Jansen, Mieke; Vergauwen, Lucia; Vandenbrouck, Tine; Knapen, Dries; Dom, Nathalie; Spanier, Katina I; Cielen, Anke; De Meester, Luc

    2013-07-01

    Microarrays are an ideal tool to screen for differences in gene expression of thousands of genes simultaneously. However, often commercial arrays are not available. In this study, we performed microarray analyses to evaluate patterns of gene transcription following exposure to two natural and one anthropogenic stressor. cDNA microarrays compiled of three life stage specific and three stressor-specific EST libraries, yielding 1734 different EST sequences, were used. We exposed juveniles of the water flea Daphnia magna for 48, 96 and 144 h to three stressors known to exert strong selection in natural populations of this species i.e. a sublethal concentration of the pesticide carbaryl, infective spores of the endoparasite Pasteuria ramosa, and fish predation risk mimicked by exposure to fish kairomones. A total of 148 gene fragments were differentially expressed compared to the control. Based on a PCA, the exposure treatments were separated into two main groups based on the extent of the transcriptional response: a low and a high (144 h of fish or carbaryl exposure and 96 h of parasite exposure) stress group. Firstly, we observed a general stress-related transcriptional expression profile independent of the treatment characterized by repression of transcripts involved in transcription, translation, signal transduction and energy metabolism. Secondly, we observed treatment-specific responses including signs of migration to deeper water layers in response to fish predation, structural challenge of the cuticle in response to carbaryl exposure, and disturbance of the ATP production in parasite exposure. A third important conclusion is that transcription expression patterns exhibit stress-specific changes over time. Parasite exposure shows the most differentially expressed gene fragments after 96 h. The peak of differentially expressed transcripts came only after 144 h of fish exposure, while carbaryl exposure induced a more stable number of differently expressed gene

  7. Comparison of toxicity of congener-153 of PCB, PBB, and PBDE to Daphnia magna.

    Science.gov (United States)

    Nakari, Tarja; Huhtala, Sami

    2008-10-01

    Acute and reproductive toxicity tests were performed to assess the effects of two polybrominated flame retardants, polybrominated biphenyl (PBB)-153, polybrominated diphenyl ether (PBDE)-153, and polychlorinated biphenyl (PCB)-153 on Daphnia magna. According to the 24-h acute toxicity test, up to concentration of 210 microg/L, these chemicals were not toxic to Daphnia. In the reproductive tests, we used concentrations of 12.5, 25, 50, and 100 microg/L. At the concentrations of 50 and 100 microg/L, the Daphnia started to die after the second test day, and there were no Daphnia alive on the fourth test day. The testing was continued using the concentrations of 12.5 and 25 microg/L. The reproductive tests were then repeated using only concentrations of 12.5 and 25 microg/L. The results, based on the weight per volume (w/v) concentrations, showed that of the three compounds we tested PCB-153 had the most severe effects on the Daphnia reproduction. PBDE-153 was the least toxic, although in this group, too, offspring production was significantly lower and mortality significantly higher than those in the control group. Also, it was observed that PCB-153 accumulated into the parent Daphnia nearly three times more actively than the two other chemicals we tested. These chemicals, although having very similar structures, seem to affect differently the reproduction of Daphnia. They also seem to accumulate differently into Daphnia. Thus, further research data are needed to understand the mechanisms responsible for the effects caused by these kinds of chemicals and to assess their risks accurately.

  8. Accumulation and inactivation of avian influenza virus by the filter-feeding invertebrate Daphnia magna.

    Science.gov (United States)

    Meixell, Brandt W; Borchardt, Mark A; Spencer, Susan K

    2013-12-01

    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.

  9. Secreted protein eco-corona mediates uptake and impacts of polystyrene nanoparticles on Daphnia magna.

    Science.gov (United States)

    Nasser, Fatima; Lynch, Iseult

    2016-03-30

    Nanoparticles (NPs) are defined as having at least one external dimension between 1 and 100 nm. Due to their small size, NPs have a large surface area to volume ratio giving them unique characteristics that differ from bulk material of the same chemical composition. As a result these novel materials have found numerous applications in medical and industrial fields with the result that environmental exposure to NPs is increasingly likely. Similarly, increased reliance on plastic, which degrades extremely slowly in the environment, is resulting in increased accumulation of micro-/nano-plastics in fresh and marine waters, whose ecotoxicological impacts are as yet poorly understood. Although NPs are well known to adsorb macromolecules from their environment, forming a biomolecule corona which changes the NP identity and how it interacts with organisms, significantly less research has been performed on the ecological corona (eco-corona). Secretion of biomolecules is a well established predator-prey response in aquatic food chains, raising the question of whether NPs interact with secreted proteins, and the impact of such interaction on NP uptake and ecotoxicity. We report here initial studies, including optimisation of protocols using carboxylic-acid and amino modified spherical polystyrene NPs, to assess interaction of NPs with biomolecules secreted by Daphnia magna and the impact of these interactions on NP uptake, retention and toxicity towards Daphnia magna. Daphnia magna are an important environmental indicator species who may be especially sensitive to nanoparticles (NPs) as a result of being filter-feeders. This paper demonstrates for the first time that proteins released by Daphnia magna create an eco-corona around polystyrene NPs which causes heightened uptake of the NPs and consequently increases toxicity. The secreted protein eco-corona also causes the NPs to be less efficiently removed from the gut of D. magna and NPs remaining in the gut of D. magna

  10. A fluorescence-based hydrolytic enzyme activity assay for quantifying toxic effects of Roundup® to Daphnia magna

    DEFF Research Database (Denmark)

    Ørsted, Michael; Roslev, Peter

    2015-01-01

    Daphnia magna is a widely used model organism for aquatic toxicity testing. In the present study, we investigated the hydrolytic enzyme activity of D. magna after exposure to toxicant stress. In vivo enzyme activity was quantified using 15 fluorogenic enzyme probes based on 4-methylumbelliferyl o...... that the fluorescence based hydrolytic enzyme activity assay (FLEA assay) can be used as an index of D. magna stress. Combining enzyme activity with fluorescence measurements may be applied as a simple and quantitative supplement for toxicity testing with D. magna....

  11. The mysid Siriella armata as a model organism in marine ecotoxicology: comparative acute toxicity sensitivity with Daphnia magna.

    Science.gov (United States)

    Pérez, Sara; Beiras, Ricardo

    2010-01-01

    Siriella armata (Crustacea, Mysidacea) is a component of the coastal zooplankton that lives in swarms in the shallow waters of the European neritic zone, from the North Sea to the Mediterranean. Juveniles of this species were examined as standard test organisms for use in marine acute toxicity tests. The effects of reference toxicants, three trace metals (Copper, Cadmium and Zinc), and one surfactant, sodium dodecyl sulfate (SDS) were studied on S. armata neonates (\\24 h) reared in the laboratory. Acute toxicity tests were carried out with filtered sea water on individual chambers (microplate wells for metals or glass vials for SDS) incubated in an isothermal room at 20 degrees C, with 16 h light: 8 h dark photoperiod for 96 h. Each neonate was fed daily with 10-15 nauplii of Artemia salina. Acute (96 h) LC50 values, in increasing order, were 46.9 lg/L for Cu, 99.3 lg/L for Cd, 466.7 lg/L for Zn and 8.5 mg/L for SDS. The LC(10), NOEC and LOEC values were also calculated. Results were compared with Daphnia magna, a freshwater cladoceran widely used as a standard ecotoxicological test organism. Acute (48 h) LC(50) values were 56.2 lg/L for Cu, 571.5 lg/L for Cd, 1.3 mg/L for Zn and 27.3 mg/L for SDS. For all the reference toxicants studied, the marine mysid Siriella armata showed higher sensitivity than the freshwater model organism Daphnia magna, validating the use of Siriella mysids as model organisms in marine acute toxicity tests.

  12. Combined Effect of Ethanol and Acetaminophen on the Central Nervous System of Daphnia magna

    Directory of Open Access Journals (Sweden)

    Brigid Bleaken

    2010-01-01

    Full Text Available The combined consumption of acetaminophen (APAP and ethanol (EtOH has been an issue with clinical implications. Previous findings regarding the simultaneous consumption of APAP and EtOH have reported harmful effects on the liver and stomach; however, little is known about the effects on the central nervous system (CNS. We hypothesized that EtOH and APAP will have a synergistic effect on the CNS of Daphnia magna (D. magna, causing a pronounced decrease in heart rate at a toxic dose of EtOH. To better understand the effects of the combined consumption of EtOH and APAP on the CNS, the heart rates of D. magna were measured under a dissection microscope after exposure to EtOH, APAP, or a combined EtOH-APAP solution. Interestingly, the average heart rates of D. magna exposed to the EtOH-APAP solution and D. magna exposed only to APAP were approximately the same. Although our results did not support our original hypothesis, the data demonstrated that APAP exerted a dominant effect over EtOH. APAP and EtOH are known to have inhibitory effects on the CNS. Therefore, these findings suggest that APAP and EtOH may compete against each other on similar pathways to be the substance that exerts an inhibitory effect in the CNS.

  13. Oil sands process-affected water impairs feeding by Daphnia magna.

    Science.gov (United States)

    Lari, Ebrahim; Steinkey, Dylan; Morandi, Garrett; Rasmussen, Joseph B; Giesy, John P; Pyle, Greg G

    2017-05-01

    Growth in extraction of bitumen from oil sands has raised concerns about influences of this industry on surrounding environments. Water clearance rate (a surrogate of feeding rate by Daphnia magna) in water containing D. magna exposed to oil sands process-affected water (OSPW) and its principal components, dissolved component (DC) and suspended particulate matter (SPM), was reduced to 72, 29, and 59% of controls, respectively. This study also examined several possible mechanisms for the observed changes algal cell density (i.e., feeding rate). There was no change in the digestive enzymes trypsin or amylase when D. magna were exposed to DC or SPM; however, exposure to total OSPW reduced trypsin activity. Mandible rolling or post-abdominal rejections, which are indicators of feeding and palatability of food, were not affected by any exposures to OSPW. Beating of thoracic limbs, which provides water flow toward the feeding groove, was reduced by exposure to SPM or total OSPW. Peristaltic activity was reduced by exposure to DC, which then might result in reduced digestion time in D. magna exposed to DC, SPM or whole OSPW. All treatments caused an increase in numbers of intact algae cells in the hindgut and excreted material. These results suggest that both DC and SPM affect feeding of D. magna by impairing actions of the digestive system, but most probably not by reducing rates of ingestion.

  14. Evaluation of acute toxicity and teratogenic effects of plant growth regulators by Daphnia magna embryo assay.

    Science.gov (United States)

    Wang, Kai-Sung; Lu, Chi-Yuan; Chang, Shih-Hsien

    2011-06-15

    This study selected common plant growth regulators (Atonik, Cytokinin, Ethephon, Gibberellic acid and Paclobutrazol) to investigate their biological toxicity to the waters of the important biological indicator Daphnia magna. The methods used in this study included traditional neonate acute toxicity test, new Daphnia embryo toxicity test, and teratogenic embryo test. The study concluded that the acute toxicity of the five PGRs to Daphnia neonate had EC(50) value range of 1.9-130.5 mg l(-1), while acute toxicity of PGRs on Daphnia embryo had EC(50) value range of 0.2-125 mg l(-1); the Daphnia embryos' LOEC values (0.05-48 mg l(-1)) for the five PGRs were lower than embryo EC(50) values. The toxic ratios of 48 h EC(50) (neonate)/48 h LOEC (embryo) for 5 PGRs were 19-512 times. The study found that teratogenic effects of Paclobutrazol and Cytokinin induced in embryo were higher than those of most other PGRs. Microscopic observation of the teratogenic effects showed that all 5 PGRs induced malformations of the second antenna, rostrum, Malpighian tube, sensory bristles, and tail spine as well as function loss and death.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Toxicity of three strobilurins (kresoxim-methyl, pyraclostrobin, and trifloxystrobin) on Daphnia magna.

    Science.gov (United States)

    Cui, Feng; Chai, Tingting; Liu, Xiaoxu; Wang, Chengju

    2017-01-01

    Strobilurins constitute a new class of fungicides that is the most widely used in the world. The present study was conducted to investigate the aquatic toxicity of 3 common strobilurin fungicides (kresoxim-methyl, pyraclostrobin, and trifloxystrobin) to Daphnia magna. The neonate acute immobilization test showed that the 48-h 50% effective concentration (EC50) values of kresoxim-methyl, pyraclostrobin, and trifloxystrobin were 443.3 µg/L, 20.9 µg/L, and 23.0 µg/L, respectively. In addition, the 3 strobilurins significantly induced activity of the important detoxification enzyme glutathione S-transferase (GST) in D. magna, and there was a significant positive relationship between GST activity and immobility of D. magna after acute exposure. The 3 strobilurins showed higher toxicity to D. magna embryos, and the 48-h EC50 were 157.3 µg/L, 3.9 µg/L, and 1.7 µg/L for kresoxim-methyl, pyraclostrobin, and trifloxystrobin, respectively. The 21-d chronic test revealed that the strobilurins could also significantly affect the reproduction, development, and growth of D. magna at sublethal concentrations. The lowest-observed-effect concentrations of kresoxim-methyl, pyraclostrobin, and trifloxystrobin for reproduction were 20 µg/L, 0.15 µg/L, and 0.2 µg/L, respectively, which were close to environmental concentrations. The findings indicate that strobilurin fungicides are very toxic to D. magna and they are sufficient to cause harm to D. magna at environmentally relevant concentrations. Environ Toxicol Chem 2017;36:182-189. © 2016 SETAC. © 2016 SETAC.

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

    Science.gov (United States)

    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

  18. Toxicity Assessment of Titanium (IV) Oxide Nanoparticles Using Daphnia magna (Water Flea).

    Science.gov (United States)

    Bang, Seung Hyuck; Le, Thai-Hoang; Lee, Sung Kyu; Kim, Pil; Kim, Jong Soo; Min, Jiho

    2011-01-01

    Titanium dioxide (TiO(2)), a common nanoparticle widely used in industrial production, is one of nano-sized materials. The purpose of this study was to determine the acute and chronic toxicity of TiO(2) using different size and various concentrations on Daphnia magna. In the acute toxicity test, four concentrations (0, 0.5, 4, and 8 mM) for TiO(2) with 250 or 500 nm and five concentrations (0, 0.25, 0.5, 0.75, and 1 mM) for TiO(2) with 21 nm were selected to analyze the toxic effect to three groups of ten daphnia neonates over 96 hours. In addition, to better understand their toxicity, chronic toxicity was examined over 21 days using 0, 1, and 10 mM for each type of TiO(2). Our results showed that all organisms died before the reproduction time at a concentration of 10 mM of TiO(2). In addition, the exposure of anatase (21 nm) particles were more toxic to D. magna, comparing with that of anatase (250 nm) and rutile (500 nm) particles. This study indicated that TiO(2) had adverse impacts on the survival, growth and reproduction of D. magna after the 21days exposure. In addition, the number of test organisms that were able to reproduce neonates gradually were reduced as the size of TiO(2) tested was decreased.

  19. Metabolomic responses to sublethal contaminant exposure in neonate and adult Daphnia magna.

    Science.gov (United States)

    Wagner, Nicole D; Simpson, André J; Simpson, Myrna J

    2017-04-01

    The use of consumer products and pharmaceuticals that act as contaminants entering waterways through runoff and wastewater effluents alters aquatic ecosystem health. Traditional toxicological endpoints may underestimate the toxicity of contaminants, as lethal concentrations are often orders of magnitude higher than those found within freshwater ecosystems. While newer techniques examine the metabolic responses of sublethal contaminant exposure, there has been no direct comparison with ontogeny in Daphnia. It was hypothesized that Daphnia magna would have distinct metabolic changes after 3 different sublethal contaminant exposures, because of differences in the toxic mode of action and ontogeny. To test this hypothesis, the proton nuclear magnetic resonance metabolomic profiles were measured in D. magna aged day 0 and 18 after exposure to 28% of the lethal concentration of 50% of organisms tested (LC50) of atrazine, propranolol, and perfluorooctanesulfonic acid (PFOS) for 48 h. Principal component analysis revealed significant separation of contaminants from the control daphnids in both neonates and adults exposed to propranolol and PFOS. In contrast, atrazine exposure caused separation from the controls in only the adult D. magna. Minimal ontogenetic changes in the targeted metabolites were seen after exposure to propranolol. For both atrazine and PFOS exposures ontogeny exhibited unique changes in the targeted metabolites. These results indicate that, depending on the contaminant studied, neonates and adults respond uniquely to sublethal contaminant exposure. Environ Toxicol Chem 2017;36:938-946. © 2016 SETAC. © 2016 SETAC.

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Mimicking Daphnia magna bioassay performance by an electronic tongue for urban water quality control

    Energy Technology Data Exchange (ETDEWEB)

    Kirsanov, Dmitry, E-mail: d.kirsanov@gmail.com [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Legin, Evgeny [Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation); Sensor Systems LLC, St. Petersburg (Russian Federation); Zagrebin, Anatoly; Ignatieva, Natalia; Rybakin, Vladimir [Institute of Limnology, Russian Academy of Sciences, St. Petersburg (Russian Federation); Legin, Andrey [Laboratory of Chemical Sensors, St. Petersburg State University, St. Petersburg (Russian Federation); Laboratory of Artificial Sensor Systems, ITMO University, St. Petersburg (Russian Federation)

    2014-05-01

    Highlights: • -Daphnia magna bioassay can be simulated with multisensor system. • Urban water toxicity can be predicted from potentiometric ET data. • Independent test set validation confirms statistical significance of the results. - Abstract: Toxicity is one of the key parameters of water quality in environmental monitoring. However, being evaluated as a response of living beings (as their mobility, fertility, death rate, etc.) to water quality, toxicity can only be assessed with the help of these living beings. This imposes certain restrictions on toxicity bioassay as an analytical method: biotest organisms must be properly bred, fed and kept under strictly regulated conditions and duration of tests can be quite long (up to several days), thus making the whole procedure the prerogative of the limited number of highly specialized laboratories. This report describes an original application of potentiometric multisensor system (electronic tongue) when the set of electrochemical sensors was calibrated against Daphnia magna death rate in order to perform toxicity assessment of urban waters without immediate involvement of living creatures. PRM (partial robust M) and PLS (projections on latent structures) regression models based on the data from this multisensor system allowed for prediction of toxicity of unknown water samples in terms of biotests but in the fast and simple instrumental way. Typical errors of water toxicity predictions were below 20% in terms of Daphnia death rate which can be considered as a good result taking into account the complexity of the task.

  2. Proteomic analysis of Daphnia magna hints at molecular pathways involved in defensive plastic responses

    Science.gov (United States)

    2014-01-01

    Background Phenotypic plasticity in defensive traits occurs in many species when facing heterogeneous predator regimes. The waterflea Daphnia is well-known for showing a variety of these so called inducible defences. However, molecular mechanisms underlying this plasticity are poorly understood so far. We performed proteomic analysis on Daphnia magna exposed to chemical cues of the predator Triops cancriformis. D. magna develops an array of morphological changes in the presence of Triops including changes of carapace morphology and cuticle hardening. Results Using the 2D-DIGE technique, 1500 protein spots could be matched and quantified. We discovered 179 protein spots with altered intensity when comparing Triops exposed animals to a control group, and 69 spots were identified using nano-LC MS/MS. Kairomone exposure increased the intensity of spots containing muscle proteins, cuticle proteins and chitin-modifying enzymes as well as enzymes of carbohydrate and energy metabolism. The yolk precursor protein vitellogenin decreased in abundance in 41 of 43 spots. Conclusion Identified proteins may be either directly involved in carapace stability or reflect changes in energy demand and allocation costs in animals exposed to predator kairomones. Our results present promising candidate proteins involved in the expression of inducible defences in Daphnia and enable further in depth analysis of this phenomenon. PMID:24762235

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

    Science.gov (United States)

    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

  4. Silver nanoparticles and silver nitrate induce high toxicity to Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Fabianne, E-mail: ribeiro.f@ua.pt [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal); Gallego-Urrea, Julián Alberto [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Jurkschat, Kerstin; Crossley, Alison [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Hassellöv, Martin [Department of Chemistry and Molecular Biologyx, University of Gothenburg, Kemivägen 4, 41296 Gothenburg (Sweden); Taylor, Cameron [Department of Materials, Oxford University Begbroke Science Park OX5 1PF (United Kingdom); Soares, Amadeu M.V.M.; Loureiro, Susana [Department of Biology and CESAM, University of Aveiro. Campus Universitario de Santiago, 3810-193. Aveiro (Portugal)

    2014-01-01

    Silver nanoparticles (AgNP) have gained attention over the years due to the antimicrobial function of silver, which has been exploited industrially to produce consumer goods that vary in type and application. Undoubtedly the increase of production and consumption of these silver-containing products will lead to the entry of silver compounds into the environment. In this study we have used Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio as model organisms to investigate the toxicity of AgNP and AgNO{sub 3} by assessing different biological endpoints and exposure periods. Organisms were exposed following specific and standardized protocols for each species/endpoints, with modifications when necessary. AgNP were characterized in each test-media by Transmission Electron Microscopy (TEM) and experiments were performed by Dynamic Light Scattering (DLS) to investigate the aggregation and agglomeration behavior of AgNP under different media chemical composition and test-period. TEM images of AgNP in the different test-media showed dissimilar patterns of agglomeration, with some agglomerates inside an organic layer, some loosely associated particles and also the presence of some individual particles. The toxicity of both AgNO{sub 3} and AgNP differ significantly based on the test species: we found no differences in toxicity for algae, a small difference for zebrafish and a major difference in toxicity for Daphnia magna. - Highlights: •Effects of silver nanoparticles and nitrate were compared in three aquatic species. •The presence of food on the immobilization assay for Daphnia magna significantly decreased AgNP toxicity. •AgNP and AgNO{sub 3} differ in toxicity according to the test species and endpoint. •AgNP and AgNO{sub 3} induced dissimilar abnormalities on zebrafish embryos' development. •AgNP behavior in the test media will rule its bioavailability and uptake and therefore toxicity.

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

    Science.gov (United States)

    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.

  6. Molecular toxicity identification evaluation (mTIE) approach predicts chemical exposure in Daphnia magna.

    Science.gov (United States)

    Antczak, Philipp; Jo, Hun Je; Woo, Seonock; Scanlan, Leona; Poynton, Helen; Loguinov, Alex; Chan, Sarah; Falciani, Francesco; Vulpe, Chris

    2013-10-15

    Daphnia magna is a bioindicator organism accepted by several international water quality regulatory agencies. Current approaches for assessment of water quality rely on acute and chronic toxicity that provide no insight into the cause of toxicity. Recently, molecular approaches, such as genome wide gene expression responses, are enabling an alternative mechanism based approach to toxicity assessment. While these genomic methods are providing important mechanistic insight into toxicity, statistically robust prediction systems that allow the identification of chemical contaminants from the molecular response to exposure are needed. Here we apply advanced machine learning approaches to develop predictive models of contaminant exposure using a D. magna gene expression data set for 36 chemical exposures. We demonstrate here that we can discriminate between chemicals belonging to different chemical classes including endocrine disruptors and inorganic and organic chemicals based on gene expression. We also show that predictive models based on indices of whole pathway transcriptional activity can achieve comparable results while facilitating biological interpretability.

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

    Science.gov (United States)

    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.

  8. Effect of an Aspartame-Ethanol Mixture on Daphnia magna Cardiac Activity

    Directory of Open Access Journals (Sweden)

    Rebecca Kohn

    2009-01-01

    Full Text Available Aspartame in conjunction with alcohol has been shown to increase the blood alcohol level in humans faster than alcohol and sucrose (Wu et al., 2006. To determine the potential effects of various mixtures of ethanol and aspartame on the nervous system, the heart rate of Daphnia magna (D.magna, water flea was measured in deionized water (control, ethanol, aspartame, and five different mixtures of ethanol and aspartame. The heart rate was chosen as a representative measure since it is controlled by the nervous system and the heart rate of D.magna can easily be measured. The results were statistically evaluated by student’s t-test. A significant increase in heart rate was observed for all mixed assays compared to both control and ethanol, but not to aspartame. The data suggests that the aspartame and alcohol mixture have a greater effect on D. magna heart rate than water or ethanol, but not aspartame alone. We propose that alcohol in combination with aspartame has potentially detrimental consequences for the nervous system.

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

    Science.gov (United States)

    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.

  10. Three-dimensional analysis of the swimming behavior of Daphnia magna exposed to nanosized titanium dioxide.

    Directory of Open Access Journals (Sweden)

    Christian Noss

    Full Text Available 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.

  11. Effects of melatonin and ethanol on the heart rate of Daphnia magna

    Directory of Open Access Journals (Sweden)

    Rebecca Kohn

    2009-01-01

    Full Text Available Melatonin, an endogenous hormone that may regulate circadian rhythms by modulating cholinergic activity, is increasing in popular use as a natural treatment for sleep disorders. However, the effects of melatonin on the human heart are not well characterized, and the consequences of combining alcohol with melatonin are unknown. The myogenic heart of the water flea Daphnia magna (D. magna is regulated by inhibitory cholinergic neurons that modulate cardiac function, including heart rate. D. magna is a useful model organism for cardiovascular function, due to its physical transparency and susceptibility to cardioactive drugs known to affect the human heart. In this study, the effects of immersion in 10 mg/L melatonin and 5% ethanol on the heart rate of D. magna were quantified. Two-hour exposure to melatonin caused a significant decrease in heart rate, from 228 ± 2 bpm to 167 ± 8 bpm. Six-minute immersion in ethanol also significantly depressed the heart rate to 176 ± 10 bpm. Pretreatment with melatonin prior to the addition of ethanol resulted in a greater decrease in heart rate (89 ± 7 bpm than ethanol or melatonin alone. These findings indicate that melatonin and alcohol may combine to cause a greater depressive effect on cardiac function.

  12. Food availability affects the strength of mutualistic host–microbiota interactions in Daphnia magna

    Science.gov (United States)

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

    2016-01-01

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Acute and chronic toxicity of emerging contaminants, alone or in combination, in Chlorella vulgaris and Daphnia magna.

    Science.gov (United States)

    Pablos, María Victoria; García-Hortigüela, Pilar; Fernández, Carlos

    2015-04-01

    This work presents the toxicity results of different compounds classified as emerging contaminants on primary producers and primary consumers in the aquatic compartment. The objectives were to (1) obtain acute and chronic toxicity results for algae and Daphnia magna using standardised or currently used tests, (2) study the relationship between the effects on the impaired feeding rate for daphnia and the effects of reproduction and (3) examine the responses on daphnia and algae after binary combinations of environmentally relevant compounds and perfluorooctane sulfonate (PFOS). Toxicity data on personal care products (PCPs), not reported in the scientific literature up to now, are presented. The results confirmed that the Daphnia feeding bioassay can be a sensitive, ecologically relevant endpoint to detect sublethal effects and could complement the information obtained with the reproduction test on Daphnia. The results also suggested that the concomitant occurrence of PFOS and other emerging contaminants in the aquatic compartment could affect the toxicity of some compounds according to their lipophilicity.

  16. ACUTE AND CHRONIC TOXICITY OF PHENYL QUINOLINE ON WATER FLEA DAPHNIA MAGNA

    Directory of Open Access Journals (Sweden)

    Hildebrando Ayala

    2012-06-01

    Full Text Available The aquatic ecotoxicological determination of phytonematicide products using the zooplanktonic cladoceran Daphnia magna is important for environmental risk assessment. Evaluations were made of the acute median lethal concentration (LC50 of phenyl quinoline on D. magna, that was 4.12 ug i.a. L-1 at 48 h of exposure. The chronic effects of phenyl quinoline in the mortality rate of the cladoceran D. magna at 17 d of exposure, with 0.18 ug ai L-1 of LOEC (Lowest Observed Effect Concentration and 0.072 ug ai L-1 of NOEC (No Observed Effect Concentration were determined. Evaluations of the chronic effect of phenyl quinoline on three parameters of growth of D. magna (total length, antenna length and caudal length to 17 d of exposure, only showed significant differences in length of the antenna between the control and 0.072 ug ai L-1 been this the value of LOEC and thus the lower concentration 0.0288 ug ai L-1, the NOEC value for phenyl quinoline. The ratio between acute and chronic toxicity (RAC for the relationship showed acute 48 h exposure on mortality NOEC 17 d a value of 57.22, and for the ratio of acute NOEC on of the length of the antenna to 17 d was a value of 143. The environmental risk assessment (ERA shows that the PEC (Probable Effect Concentration / PNEC (Predicted No-Effect Concentration for acute assay was 582 524 and for the PEC / PNEC for chronic test was 83 333 333. These results demonstrate that phenyl quinoline has a high impact on aquatic biota represented by the trophic level that belongs to D. magna, and therefore shows that the substance is a candidate for a comprehensive ecotoxicological assessment.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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 (cartap or 40 microg/L of cypermethrin. The mixture of both compounds showed no synergistic toxicity. The extremely high acute-to-chronic ratio suggests that the standard acute lethal toxicity assessment might not reflect the true environmental hazards of these frequently used pesticides. Ecological hazard assessments of long-term low dose or pulsed exposures to cartap and cypermethrin may reveal more realistic consequences of these compounds in

  20. Effects of Perfluorooctane sulfonate on immobilization, heartbeat, reproductive and biochemical performance of Daphnia magna.

    Science.gov (United States)

    Liang, Ruoyu; He, Jiao; Shi, Yajuan; Li, Zhifen; Sarvajayakesavalu, Suriyanarayanan; Baninla, Yvette; Guo, Feifan; Chen, Juan; Xu, Xiangbo; Lu, Yonglong

    2017-02-01

    In recent years, Perfluorooctane sulfonate (PFOS) was widely detected in Yellow-Bohai Sea and other areas, causing a series of adverse effects in aquatic organisms. However, present studies of its chronic and acute toxicity on aquatic organisms were far more inadequate. Therefore, in the present study, Daphnia magna was used to investigate PFOS toxicity on their immobilization, heartbeat, reproductive and biochemical performance in acute, subchronic and chronic exposure. The results showed that the 48h-EC50 value for immobilization was 79.35 mg L(-1) and the toxicity was classified as intermediate. Heartbeat was significantly stimulated and reproductive parameters were significantly suppressed by PFOS, which can be used to reflect the toxicological effects on individuals. On the other hand, intrinsic rate of natural increase was more sensitive than reproductive parameters, which indicated negative responses on population dynamics of Daphnia magna. In addition, there were different degrees of inhibition on GST, CAT and ChE activity, which indicated three types of enzyme could become biomarkers to chronic PFOS exposure. Most of selected and evaluated endpoints have significant sensitivity to PFOS at the concentration of 8 mg L(-1) during subchronic and chronic exposure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Biology-based modeling to analyze uranium toxicity data on Daphnia magna in a multigeneration study.

    Science.gov (United States)

    Massarin, Sandrine; Beaudouin, Remy; Zeman, Florence; Floriani, Magali; Gilbin, Rodolphe; Alonzo, Frederic; Pery, Alexandre R R

    2011-05-01

    Recent studies have investigated chronic toxicity of waterborne depleted uranium on the life cycle and physiology of Daphnia magna. In particular, a reduction in food assimilation was observed. Our aims here were to examine whether this reduction could fully account for observed effects on both growth and reproduction, for three successive generations, and to investigate through microscope analyses whether this reduction resulted from direct damage to the intestinal epithelium. We analyzed data obtained by exposing Daphnia magna to uranium over three successive generations. We used energy-based models, which are both able to fit simultaneously growth and reproduction and are biologically relevant. Two possible modes of action were compared - decrease in food assimilation rate and increase in maintenance costs. In our models, effects were related either to internal concentration or to exposure concentration. The model that fitted the data best represented a decrease in food assimilation related to exposure concentration. Furthermore, observations of consequent histological damage to the intestinal epithelium, together with uranium precipitates in the epithelial cells, supported the assumption that uranium has direct effects on the digestive tract. We were able to model the data in all generations and showed that sensitivity increased from one generation to the next, in particular through a significant increase of the intensity of effect, once the threshold for appearance of effects was exceeded.

  2. Application of enriched stable isotope technique to the study of copper bioavailability in Daphnia magna

    Institute of Scientific and Technical Information of China (English)

    Wenhong Fan; Chenguang Wu; Chunmei Zhao; Tao Yu; Yuan Zhang

    2011-01-01

    The biokinetics of Cu in Daphnia magna, including dissolved uptake, assimilation and efflux, has been determined using a gamma 67Cu radiotracer methodology.However, this gamma emitting radioisotope is not readily available due to its very short half-life.In the present study, we employed a stable isotope tracer (65Cu) to determine the Cu biokinetics and compared our results to those determined using 67Cu.The dissolved uptake rate constant of 65Cu was 3.36 L/(g·day), which is higher than that of 67Cu (1.32 L/(g·day)).With increasing food concentrations from 2×104 to 1×105 cells/mL, the Cu assimilation efficiency (AE) decreased from 46% to 11%,compared to a decrease from 27% to 16% when determined using 67Cu.The efflux of Cu from Daphnia magna was quantified following both dissolved and dietary uptake.The efflux of waterborne Cu was comparable to that of dietborne Cu and the efflux rate constant (0.32-0.52 day-1) was higher than that determined by 67Cu (0.19-0.20 day-1).By considering different water properties and handling procedure between the two experiments, we believe that these differences are reasonable.Overall, this study demonstrated that the enriched stable isotope tracer technique is a powerful tool to investigate metal bioavailability and maybe a good alternative to radioactive measurements.

  3. Parasitism drives host genome evolution: Insights from the Pasteuria ramosa-Daphnia magna system.

    Science.gov (United States)

    Bourgeois, Yann; Roulin, Anne C; Müller, Kristina; Ebert, Dieter

    2017-04-01

    Because parasitism is thought to play a major role in shaping host genomes, it has been predicted that genomic regions associated with resistance to parasites should stand out in genome scans, revealing signals of selection above the genomic background. To test whether parasitism is indeed such a major factor in host evolution and to better understand host-parasite interaction at the molecular level, we studied genome-wide polymorphisms in 97 genotypes of the planktonic crustacean Daphnia magna originating from three localities across Europe. Daphnia magna is known to coevolve with the bacterial pathogen Pasteuria ramosa for which host genotypes (clonal lines) are either resistant or susceptible. Using association mapping, we identified two genomic regions involved in resistance to P. ramosa, one of which was already known from a previous QTL analysis. We then performed a naïve genome scan to test for signatures of positive selection and found that the two regions identified with the association mapping further stood out as outliers. Several other regions with evidence for selection were also found, but no link between these regions and phenotypic variation could be established. Our results are consistent with the hypothesis that parasitism is driving host genome evolution. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  4. Development and validation of an individual based Daphnia magna population model: The influence of crowding on population dynamics

    NARCIS (Netherlands)

    Preuss, T.G.; Hammers-Wirtz, M.; Hommen, U.; Rubach, M.N.; Ratte, H.T.

    2009-01-01

    An individual-based model was developed to predict the population dynamics of Daphnia magna at laboratory conditions from individual life-history traits observed in experiments with different feeding conditions. Within the model, each daphnid passes its individual life cycle including feeding on alg

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

    Science.gov (United States)

    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 ...

  6. Ingestion of micro- and nanoplastics in Daphnia magna – Quantification of body burdens and assessment of feeding rates and reproduction

    DEFF Research Database (Denmark)

    Rist, Sinja; Baun, Anders; Hartmann, Nanna B.

    2017-01-01

    a quantitative approach for determining ingestion and egestion of micro- and nanoplastics in Daphnia magna and to analyze the influence of particle size, exposure duration and the presence of food. One week old animals were exposed to 2 µm and 100 nm fluorescent polystyrene beads (1 mg/l) for 24 h, followed...

  7. Strain difference in sensitivity to 3,4-dichloroaniline and insect growth regulator, fenoxycarb, in Daphnia magna

    DEFF Research Database (Denmark)

    Oda, S.; Tatarazako, N.; Dorgerloh, M

    2007-01-01

    Acute and reproductive toxicity tests were conducted on seven strains of Daphnia magna from six laboratories in five countries. 3,4-Dichloroaniline (DCA) and fenoxycarb were used as test chemicals. Acute toxicity tests revealed that estimated EC50 (50% effective concentration) values for DCA varied...

  8. A taste of plastic - quantifying micro- and nanoplastic ingestion and interactions with feeding in daphnia magna (E)

    DEFF Research Database (Denmark)

    Rist, Sinja; Baun, Anders; Hartmann, Nanna B.

    quantitative measures are analytically challenging. The aim of this study was to develop and apply a quantitative approach to measure particle body burden to study uptake and depuration of micro- and nanoplastics in the freshwater flea Daphnia magna, using fluorescent polystyrene beads. The animals were first...

  9. Life history responses of Daphnia magna feeding on toxic Microcystis aeruginosa alone and mixed with a mixotrophic Poterioochromonas species

    DEFF Research Database (Denmark)

    Zhang, Xue; Warming, Trine Perlt; Hu, Hong-Ying

    2009-01-01

    The toxic effects of a mixotrophic golden alga (Poterioochromonas sp. strain ZX1) and a cyanobacterium Microcystis aeruginosa grazed by Poterioochromonas to a cladoceran were investigated through life history experiments using Daphnia magna. Poterioochromonas cultured in two ways (fed M. aeruginosa...

  10. Ontwikkeling van sedimenttoxiciteits-toetsen. II De chronische toxiciteit van sediment gecontamineerd met chloorpyrifos voor Daphnia magna

    NARCIS (Netherlands)

    Roghair CJ; Wolters MAH; Huijs MPA

    1993-01-01

    This report presents several experiments carried out in a study to develop standardized sediment toxicity tests. The prolonged toxicity of chlorpyriphos (CPF) to the waterflea Daphnia magna was determined in a sediment/water-system, an elutriate and in Dutch Standard Water. The toxicity of CPF could

  11. Effects of the cyanobacterium Cylindrospermopsis raciborskii on feeding and life-history characteristics of the grazer Daphnia magna

    NARCIS (Netherlands)

    Soares, M.C.S.; Lürling, M.F.L.L.W.; Panosso, R.; Huszar, V.M.

    2009-01-01

    Laboratory experiments were used to test the hypothesis that feeding and growth of the zooplankton grazer Daphnia magna will decrease with increasing proportions of the cyanobacterium Cylindrospermopsis raciborskii in the diet (mixed feeds with the green alga Scenedesmus obliquus). A strain of C.

  12. The positively phototactic reaction of daphnia magna straus: A contribution to the understanding of diurnal vertical migration

    NARCIS (Netherlands)

    Ringelberg, J.

    1964-01-01

    The present investigation was aimed at gaining more insight into the physiological mechanism underlying the diurnal vertical migration of planktonic animals. The experiments were carried out on Daphnia magna. Only reactions to decreases in light intensity were studied. Kinetical aspects. Experiments

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Comparative toxicity study of Ag, Au, and Ag-Au bimetallic nanoparticles on Daphnia magna.

    Science.gov (United States)

    Li, Ting; Albee, Brian; Alemayehu, Matti; Diaz, Rocio; Ingham, Leigha; Kamal, Shawn; Rodriguez, Maritza; Bishnoi, Sandra Whaley

    2010-09-01

    A comparative assessment of the 48-h acute toxicity of aqueous nanoparticles synthesized using the same methodology, including Au, Ag, and Ag-Au bimetallic nanoparticles, was conducted to determine their ecological effect in freshwater environments through the use of Daphnia magna, using their mortality as a toxicological endpoint. D. magna are one of the standard organisms used for ecotoxicity studies due to their sensitivity to chemical toxicants. Particle suspensions used in toxicity testing were well-characterized through a combination of absorbance measurements, atomic force or electron microscopy, flame atomic absorption spectrometry, and dynamic light scattering to determine composition, aggregation state, and particle size. The toxicity of all nanoparticles tested was found to be dose and composition dependent. The concentration of Au nanoparticles that killed 50% of the test organisms (LC(50)) ranged from 65-75 mg/L. In addition, three different sized Ag nanoparticles (diameters = 36, 52, and 66 nm) were studied to analyze the toxicological effects of particle size on D. magna; however, it was found that toxicity was not a function of size and ranged from 3-4 μg/L for all three sets of Ag nanoparticles tested. This was possibly due to the large degree of aggregation when these nanoparticles were suspended in standard synthetic freshwater. Moreover, the LC(50) values for Ag-Au bimetallic nanoparticles were found to be between that of Ag and Au but much closer to that of Ag. The bimetallic particles containing 80% Ag and 20% Au were found to have a significantly lower toxicity to Daphnia (LC(50) of 15 μg/L) compared to Ag nanoparticles, while the toxicity of the nanoparticles containing 20% Ag and 80% Au was greater than expected at 12 μg/L. The comparison results confirm that Ag nanoparticles were much more toxic than Au nanoparticles, and that the introduction of gold into silver nanoparticles may lower their environmental impact by lowering the amount

  15. Differing Daphnia magna assimilation efficiencies for terrestrial, bacterial, and algal carbon and fatty acids.

    Science.gov (United States)

    Taipale, Sami J; Brett, Michael T; Hahn, Martin W; Martin-Creuzburg, Dominik; Yeung, Sean; Hiltunen, Minna; Strandberg, Ursula; Kankaala, Paula

    2014-02-01

    There is considerable interest in the pathways by which carbon and growth-limiting elemental and biochemical nutrients are supplied to upper trophic levels. Fatty acids and sterols are among the most important molecules transferred across the plant-animal interface of food webs. In lake ecosystems, in addition to phytoplankton, bacteria and terrestrial organic matter are potential trophic resources for zooplankton, especially in those receiving high terrestrial organic matter inputs. We therefore tested carbon, nitrogen, and fatty acid assimilation by the crustacean Daphnia magna when consuming these resources. We fed Daphnia with monospecific diets of high-quality (Cryptomonas marssonii) and intermediate-quality (Chlamydomonas sp. and Scenedesmus gracilis) phytoplankton species, two heterotrophic bacterial strains, and particles from the globally dispersed riparian grass, Phragmites australis, representing terrestrial particulate organic carbon (t-POC). We also fed Daphnia with various mixed diets, and compared Daphnia fatty acid, carbon, and nitrogen assimilation across treatments. Our results suggest that bacteria were nutritionally inadequate diets because they lacked sterols and polyunsaturated omega-3 and omega-6 (omega-3 and omega-6) fatty acids (PUFAs). However, Daphnia were able to effectively use carbon and nitrogen from Actinobacteria, if their basal needs for essential fatty acids and sterols were met by phytoplankton. In contrast to bacteria, t-POC contained sterols and omega-6 and omega-3 fatty acids, but only at 22%, 1.4%, and 0.2% of phytoplankton levels, respectively, which indicated that t-POC food quality was especially restricted with regard to omega-3 PUFAs. Our results also showed higher assimilation of carbon than fatty acids from t-POC and bacteria into Daphnia, based on stable-isotope and fatty acids analysis, respectively. A relatively high (>20%) assimilation of carbon and fatty acids from t-POC was observed only when the proportion of t

  16. Uptake and effects of microplastic textile fibers on freshwater crustacean Daphnia magna.

    Science.gov (United States)

    Jemec, Anita; Horvat, Petra; Kunej, Urban; Bele, Marjan; Kržan, Andrej

    2016-12-01

    Microplastic fibers (MP) from textile weathering and washing are increasingly being recognized as environmental pollutants. The majority of studies on the bioavailability and effects of microplastic focused on small polystyrene spherical plastic particles, while less data are available for fibers and for other materials besides polystyrene. We investigated the ingestion and effects of ground polyethylene terephthalate (PET) textile microfibers (length range: 62-1400 μm, width 31-528 μm, thickness 1-21.5 μm) on the freshwater zooplankton crustacean Daphnia magna after a 48 h exposure and subsequent 24 h of recovery in MP free medium and algae. The majority of ingested fibers by D. magna were around 300 μm, but also some very large twisted MP fibers around 1400 μm were found inside the gut. Exposure to these fibers results in increased mortality of daphnids after 48 h only in the case where daphnids were not pre-fed with algae prior to experiment, but no effect was found when daphnids were fed before the experiments. Regardless of the feeding regime, daphnids were not able to recover from MP exposure after additional 24 h incubation period in a MP free medium with algae. The uptake and effects of PET textile MP on D. magna are presented here for the first time.

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

    Science.gov (United States)

    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.

  18. Shape and Charge of Gold Nanomaterials Influence Survivorship, Oxidative Stress and Moulting of Daphnia magna

    Directory of Open Access Journals (Sweden)

    Fatima Nasser

    2016-11-01

    Full Text Available Engineered nanomaterials (ENMs are materials with at least one dimension between 1–100 nm. The small size of ENMs results in a large surface area to volume ratio, giving ENMs novel characteristics that are not traditionally exhibited by larger bulk materials. Coupled with large surface area is an enormous capacity for surface functionalization of ENMs, e.g., with different ligands or surface changes, leading to an almost infinite array of variability of ENMs. Here we explore the effects of various shaped (spheres, rods and charged (negative, positive gold ENMs on Daphnia magna (D. magna in terms of survival, ENM uptake and production of reactive oxygen species (ROS, a key factor in oxidative stress responses. We also investigate the effects of gold ENMs binding to the carapace of D. magna and how this may induce moulting inhibition in addition to toxicity and stress. The findings suggest that ENM shape and surface charge play an important role in determining ENM uptake and toxicity.

  19. Multigenerational effects and DNA alterations of QDs-Indolicidin on Daphnia magna.

    Science.gov (United States)

    Maselli, Valeria; Siciliano, Antonietta; Giorgio, Antonella; Falanga, Annarita; Galdiero, Stefania; Guida, Marco; Fulgione, Domenico; Galdiero, Emilia

    2017-05-01

    The complex QDs-Indolicidin (QDs-Ind) has been previously shown to be a good antimicrobial system with a low acute toxicity on Daphnia magna (D. magna). However, multigenerational effects caused by exposure to QDs-Ind and after subsequent recovery are still unknown. In this study, we performed multigenerational exposure tests and we evaluated individual fitness, population growth, DNA alteration, expression of Dhb (haemoglobin), Vtg (vitellogenin), CYP4 (cytochrome P450s CYP4 family), and CYP314 (cytochrome P450s mitochondrial family 314) genes on three generation of D. magna. Results showed that the total amount of eggs produced per female and total number of brood per female and body lengths were significantly decreased, Dhb, CYP4 were upregulated while Vtg was down-regulated except at reproduction days when it was slightly up-regulated under QDs-Ind exposure. Random Amplification of Polymorphic DNA (RAPD) method has proven to be useful to qualitative assess of DNA damage during generation and to underline modification in somatic or germinal cells. The results of the study suggest that effects of chronic exposure cannot be ignored. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  1. Toxic effect of cyanobacterial blooms on the grazing activity of Daphnia magna Straus

    Directory of Open Access Journals (Sweden)

    Maria £otocka

    2001-12-01

    Full Text Available The investigations aimed to determine the impact of cyanobacteria Microcystis aeruginosa (Kütz. Kütz. and Aphanizomenon flos-aquae (L. Ralfs ex Bornet et Flah., both toxic algae, on the grazing intensity of Daphnia magna Straus. In order to determine the parameter permitting the quantitative determination of the grazing intensity of herbivorous organisms, methods based on the following techniques were applied: microscopy, to determine the degree of gut fullness; spectrophotometry, to determine the levels of chlorophyll a and its degradation products in the food composition; high-performance liquid chromatography (HPLC to determine the content of exogenous and endogenous carotenoids. Each of these methods confirmed that the tested algae species inhibited grazing intensity in D. magna Straus. The most obvious effects were obtained when M. aeruginosa (Kütz. Kütz. was used as food. With these cyanobacteria, the gut fullness indicator did not exceed 58%, and the chlorophyll a content in the digestive system of the tested D. magna was three times lower than that in the control organisms. It seems that the defensive reaction of organisms was a reversible process. However, the possibility of a long-term, sublethal influence of cyanobacteria on the physiology and internal processes of this species cannot be ruled out.

  2. Cloning and characterization of the ecdysone receptor and ultraspiracle protein from the water flea Daphnia magna.

    Science.gov (United States)

    Kato, Yasuhiko; Kobayashi, Kaoru; Oda, Shigeto; Tatarazako, Norihisa; Watanabe, Hajime; Iguchi, Taisen

    2007-04-01

    cDNAs encoding the ecdysone receptor (EcR) and ultra spiracle (USP) protein were cloned from the water flea Daphnia magna (Crustacea: Cladocera). The deduced EcR and USP amino acid sequences showed a high degree of homology to those of other crustaceans as well as insects. We isolated three isoforms of EcR that differ in the A/B domain. Quantitative PCR analysis indicated differing temporal expression patterns of the EcR isoforms during the molting period and demonstrated that the expression of one subtype correlated well with the timing of molt. Using cDNAs encoding EcR and USP, we constructed a Daphnia EcR/USP reporter based on a two-hybrid system. The gene fusions encoded the EcR ligand-binding domain (LBD) fused to the Gal4 DNA-binding domain, and the USP-LBD fused to the Vp16 activation domain. These chimeric genes were transfected with a luciferase reporter gene. Dose-dependent activation of the reporter gene could be observed when transfectants were exposed to Ec and other chemicals known to have Ec-like activities. This two-hybrid system may represent a useful reporter system for further examination of hormonal and chemical effects on Daphnia at the molecular level.

  3. Influence of titanium dioxide nanoparticles on cadmium and lead bioaccumulations and toxicities to Daphnia magna

    Science.gov (United States)

    Li, Ling; Sillanpää, Markus; Schultz, Eija

    2017-06-01

    Titanium dioxide nanoparticles (TiO2 NPs) have attracted considerable concerns due to the increasing production and widespread applications, while their influences on other co-existing pollutants in real environment are not well studied. In this paper, the colloidal stability of TiO2 NPs in the exposure medium was first evaluated, and then, the medium was modified so that TiO2 NP suspension remained stable over the exposure period. Finally, using the optimized exposure medium, the effects of cadmium (Cd) and lead (Pb) on Daphnia magna both in the absence and presence of TiO2 NPs were investigated. Results showed that 2 mg L-1 of TiO2 NPs was well dispersed in 1:20 diluted Elendt M7 medium without EDTA, and no immobility was observed. The presence of the nanoparticles increased the bioaccumulation and toxicity of Cd to the daphnias. On the contrary, while Pb bioaccumulation was enhanced by three to four times, toxicity of Pb was reduced in the presence of TiO2 NPs. The decreased toxicity of Pb was more likely attributed to the decreased bioavailability of free Pb ion due to adsorption and speciation change of Pb in the presence of TiO2 NPs. Additionally, surface-attached TiO2 NPs combined with adsorbed heavy metals caused adverse effects on daphnia swimming and molting behavior, which is supposed to lead to chronic toxicity.

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

    Science.gov (United States)

    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.

  5. Enhanced offspring production in Daphnia magna clones exposed to serotonin reuptake inhibitors and 4-nonylphenol. Stage- and food-dependent effects.

    Science.gov (United States)

    Campos, B; Piña, B; Fernández-Sanjuán, M; Lacorte, S; Barata, C

    2012-03-01

    Risk assessment of emerging pollutants requires the development of bioassays able to detect and understand novel mechanisms of action. This study tested the hypothesis that the increase of offspring production in Daphnia magna induced by certain pollutants may be mediated through different mechanisms, depending on development stages, clones and food rations The study included two selective serotonin reuptake inhibitors (SSRIs), fluoxetine and fluvoxamine, and the detergent metabolite 4-nonylphenol. Organisms were exposed from birth to adulthood or only during adulthood at low and high food ration levels. Results indicated that low exposure levels of the three studied substances increased offspring production and/or juvenile developmental rates similarly for all studied clones, but the responses differed among life-stages and food rations. When individuals were exposed to the studied chemicals from birth, enhanced offspring production per female was observed only at low and intermediate food rations. On the contrary, when exposures started in gravid females most treatments increased offspring production. Results obtained with SSRIs support previous findings, where it was stated that these compounds may amplify serotoninergic signaling in D. magna. Nonylphenol effects may be related to the reported alteration of this compound in Daphnia ecdysteroid metabolism. Further investigations are necessary to resolve the biochemical mechanism of SSRI and nonylphenol enhancing offspring production.

  6. Development and staging of the water flea Daphnia magna (Straus, 1820; Cladocera, Daphniidae) based on morphological landmarks.

    Science.gov (United States)

    Mittmann, Beate; Ungerer, Petra; Klann, Marleen; Stollewerk, Angelika; Wolff, Carsten

    2014-03-18

    Crustaceans of the genus Daphnia are one of the oldest model organisms in ecotoxicology, ecology and evolutionary biology. The publication of the Daphnia pulex genome has facilitated the development of genetic tools to answer long-standing questions in these research fields (Science 331: 555-561, 2011). A particular focus is laid on understanding the genetic basis of the striking ability of daphnids to change their phenotype in response to environmental stressors. Furthermore, Daphnia have recently been developed into crustacean model organisms for EvoDevo research, contributing to the ongoing attempt to resolve arthropod phylogeny. These problems require the comparative analyses of gene expression and functional data, which in turn require a standardized developmental staging system for Daphnia. Here we provide a detailed staging system of the embryonic development of Daphnia magna based on morphological landmarks. The staging system does not rely on developmental hours and is therefore suitable for functional and ecological experiments, which often cause developmental delays in affected embryos and thus shifts in time reference points. We provide a detailed description of each stage and include schematic drawings of all stages showing relevant morphological landmarks in order to facilitate the application of this staging scheme. We present here a staging system for Daphnia magna, which is based on morphological landmarks. The staging system can be adopted for other daphnids with minor variations since the sequence of development is highly conserved during early stages and only minor heterochronic shifts occur in late embryonic stages.

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

    Science.gov (United States)

    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.

  8. Reduced cadmium accumulation and toxicity in Daphnia magna under carbon nanotube exposure.

    Science.gov (United States)

    Liu, Jie; Wang, Wen-Xiong

    2015-12-01

    With increasing application and commercial production, carbon nanotubes (CNTs) will inevitably be released into aquatic environments and affect the transport and toxicity of toxic metals in ecosystems. The present study examined how CNTs affected the biokinetics and toxicity of a toxic metal, cadmium (Cd), in the freshwater zooplankton Daphnia magna. The authors quantified the dissolved uptake and the 50% lethal concentration (LC50, 48 h and 72 h) of Cd in daphnids in the presence of functionalized multiwalled nanotubes (F-CNTs) with different lengths (10-30 µm vs 0.5-2 µm) and concentrations (4 mg/L and 8 mg/L). Compared with the control treatment without CNTs, both CNTs slowed down the accumulation rate of Cd in D. magna over 8 h of exposure and further reduced the accumulation thereafter. Mechanisms for the reduced Cd uptake were mainly related to the influences of CNTs on the physiological activity of daphnids. The LC50 of D. magna in the presence of Cd and shorter CNTs was almost the same as that of the control group without CNTs. However, the LC50 of the groups with normal CNTs was significantly higher than that of the control group (i.e., F-CNTs decreased Cd toxicity significantly). Meanwhile, CNTs also decreased the tolerance of D. magna to Cd. The present study suggests that different physical properties of CNTs, such as length, need to be considered in the environmental risk assessment of CNTs.

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    Shaonan Li; Yajun Tan

    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 μg/L and 0.01 to 2.00 μg/L, respectively.For exposure to triazophos, ChE was induced up to 176.5% at 1.5 μg/L and day 10 when measured by acetylthiocholine (ATCh), whereas it was induced up to 174.2% at 0.5 μg/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, respectivly, with both maximal inductions detected at 0.l μg/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.

  11. Analysis of expressed sequence tags of the water flea Daphnia magna.

    Science.gov (United States)

    Watanabe, Hajime; Tatarazako, Norihisa; Oda, Shigeto; Nishide, Hiroyo; Uchiyama, Ikuo; Morita, Masatoshi; Iguchi, Taisen

    2005-08-01

    To study gene expression in the water flea Daphnia magna we constructed a cDNA library and characterized the expressed sequence tags (ESTs) of 7210 clones. The EST sequences clustered into 2958 nonredundant groups. BLAST analyses of both protein and DNA databases showed that 1218 (41%) of the unique sequences shared significant similarities to known nucleotide or amino acid sequences, whereas the remaining 1740 (59%) showed no significant similarities to other genes. Clustering analysis revealed particularly high expression of genes related to ATP synthesis, structural proteins, and proteases. The cDNA clones and EST sequence information should be useful for future functional analysis of daphnid biology and investigation of the links between ecology and genomics.

  12. Protease activity in gut of Daphnia magna: evidence for trypsin and chymotrypsin enzymes.

    Science.gov (United States)

    von Elert, Eric; Agrawal, Manish Kumar; Gebauer, Christine; Jaensch, Heike; Bauer, Ulrike; Zitt, Anja

    2004-03-01

    Two major protease activities were present in gut homogenates of the cladoceran crustacean Daphnia magna: (i) a trypsin activity that hydrolysed the synthetic substrate N-benzoyl-dl-arginine p-nitroanilide and was strongly inhibited by N-p-tosyl-lysine chloroketone (TLCK) and 4-(amidinophenyl)methanesulfonyl fluoride (APMSF) and not inhibited by chymostatin; and (ii) a chymotrypsin activity that hydrolysed synthetic chymotrypsin substrates containing more than one amino acid, did not hydrolyse N-benzoyl-l-tyrosine p-nitroanilide, and was strongly inhibited by chymostatin and not by TLCK and APMSF. Both activities had alkaline pH optima (pH 7-10), but were shown to be due to distinct types of proteases. These two enzyme activities accounted for 75-83% of the proteolytic activity of gut contents. Substrate SDS-polyacrylamide gel electrophoresis revealed nine different proteases ranging from 15 to 73 kDa.

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

    Science.gov (United States)

    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.

  14. Acute toxicity evaluation of cutting fluids used in manufacturing processes to Poecilia reticulata and Daphnia magna

    Directory of Open Access Journals (Sweden)

    William Gerson Matias

    2006-09-01

    Full Text Available Grinding operations are very significant among the manufacturing processes of the metal-mechanic industry. In conventional grinding, cutting fluids are of great concern for improving productivity, but also for being hazardous to the environment. In order to contribute to the knowledge of the actual toxic effects of these products in aquatic environments, the present work assesses the toxicity potential through acute toxicity tests of three different kinds of cutting fluids, with three different usage times. The tests were carried out using the fish Poecilia reticulate and the microcrustacean Daphnia magna as test organisms. These tests made it possible to determine the Median Lethal Concentration (LC50 for the fish and the Median Effective Concentration (EC50 for the microcrustacean. The results indicate that, after storage, the toxicity potential of cutting fluids decreases. However, in the three situations investigated, the product presented a high toxicity potential, which reinforces the need of special care in its handling, usage and disposal.

  15. Aqueous solubility and Daphnia magna chronic toxicity of di(2-ethylhexyl) adipate.

    Science.gov (United States)

    Robillard, K A; Dufresne, D L; Gorsuch, J W; Stubblefield, W A; Staples, C A; Parkerton, T F

    2008-06-01

    A water solubility of 5.5 (+/-0.22) microg/L for di(2-ethylhexyl) adipate (DEHA) was measured using the slow-stir method. This value is consistent with computer estimations and over two orders of magnitude lower than that previously determined using the shake-flask method. We performed a 21-day chronic Daphnia magna limit test at an average exposure of 4.4 microg/L in laboratory diluent water to avoid insoluble test material and avoid physical entrapment. One hundred percent of the DEHA-treated organisms survived compared to 90% survival in both the controls and solvent controls. Mean neonate reproduction was 152, 137, and 148 and mean dry weight per surviving female was 0.804, 0.779, and 0.742 mg in the DEHA treatment, control, and solvent control, respectively. No adverse effects were observed.

  16. Mixture toxicity of three toxicants with similar and dissimilar modes of action to Daphnia magna.

    Science.gov (United States)

    Syberg, Kristian; Elleby, Anders; Pedersen, Henrik; Cedergreen, Nina; Forbes, Valery E

    2008-03-01

    Mixture toxicity of similar- and dissimilar-acting toxicants can be predicted by the models concentration addition (CA) and independent action (IA) using single substance toxicity data. Knowledge of the toxicants mode of action is thus required in order to use the models. In order to test the predictive capability of the models, we conducted Daphnia magna 48 h immobilization experiments with three toxicants with known modes of action (dimethoate, pirimicarb and linear alkyl benzene sulfonate) singly, and in binary and ternary mixtures. Our results indicate that CA and IA predict binary mixtures of similar- and dissimilar-acting toxicants equally well. CA and IA also equally predicted the ternary mixture consisting of both similar- and dissimilar-acting chemicals. The paper discusses the concept of mode of action and the implications the definition of mode of action has on the choice of reference model for mixture toxicity studies.

  17. Interclonal proteomic responses to predator exposure in Daphnia magna may depend on predator composition of habitats.

    Science.gov (United States)

    Otte, Kathrin A; Schrank, Isabella; Fröhlich, Thomas; Arnold, Georg J; Laforsch, Christian

    2015-08-01

    Phenotypic plasticity, the ability of one genotype to express different phenotypes in response to changing environmental conditions, is one of the most common phenomena characterizing the living world and is not only relevant for the ecology but also for the evolution of species. Daphnia, the water flea, is a textbook example for predator-induced phenotypic plastic defences; however, the analysis of molecular mechanisms underlying these inducible defences is still in its early stages. We exposed Daphnia magna to chemical cues of the predator Triops cancriformis to identify key processes underlying plastic defensive trait formation. To get a more comprehensive idea of this phenomenon, we studied four genotypes with five biological replicates each, originating from habitats characterized by different predator composition, ranging from predator-free habitats to habitats containing T. cancriformis. We analysed the morphologies as well as proteomes of predator-exposed and control animals. Three genotypes showed morphological changes when the predator was present. Using a high-throughput proteomics approach, we found 294 proteins which were significantly altered in their abundance after predator exposure in a general or genotype-dependent manner. Proteins connected to genotype-dependent responses were related to the cuticle, protein synthesis and calcium binding, whereas the yolk protein vitellogenin increased in abundance in all genotypes, indicating their involvement in a more general response. Furthermore, genotype-dependent responses at the proteome level were most distinct for the only genotype that shares its habitat with Triops. Altogether, our study provides new insights concerning genotype-dependent and general molecular processes involved in predator-induced phenotypic plasticity in D. magna. © 2015 John Wiley & Sons Ltd.

  18. Zinc oxide nanoparticles toxicity to Daphnia magna: size-dependent effects and dissolution.

    Science.gov (United States)

    Lopes, Sílvia; Ribeiro, Fabianne; Wojnarowicz, Jacek; Łojkowski, Witold; Jurkschat, Kerstin; Crossley, Alison; Soares, Amadeu M V M; Loureiro, Susana

    2014-01-01

    As the production of zinc oxide nanoparticles (ZnO-NPs) and other metal oxides is exponentially increasing, it is important to investigate potential environmental and health impacts of such nanoparticles. Nanoparticles' properties (e.g., size, dissolution rate) may change in different water media, and their characterization is essential to derive conclusions about toxicity results. Therefore, an aquatic model organism, Daphnia magna, was used to investigate the effect of ZnO-NPs with 2 different particle sizes (30 nm and 80-100 nm) and then compare these effects with ZnO microsized particles (>200 nm) and the ionic counterpart (in the form of ZnCl2 ) on immobilization, feeding inhibition, and reproduction endpoints. The 48-h median lethal concentration (LC50) for immobilization ranged between 0.76 mg Zn L(-1) for the ionic zinc and 1.32 mg Zn L(-1) for ZnO-NPs of 80 nm to 100 nm. For the chronic exposures, the reproduction output was impaired similarly among zinc exposures and possibly driven mainly by the zinc ionic form. The concentrations used showed a total dissolution after 48 h. On the other hand, feeding activity was more affected by the 30 nm ZnO-NPs than by the ionic zinc, showing that the particulate form was also playing an important role in the feeding inhibition of D. magna. Dissolution and particle size in the daphnia test media were found to be essential to derive conclusions on toxicity. Therefore, they can possibly be considered critical for evaluating nanoparticles' toxicity and fate.

  19. Retroconversion of docosapentaenoic acid (n-6): an alternative pathway for biosynthesis of arachidonic acid in Daphnia magna.

    Science.gov (United States)

    Strandberg, Ursula; Taipale, Sami J; Kainz, Martin J; Brett, Michael T

    2014-06-01

    The aim of this study was to assess metabolic pathways for arachidonic acid (20:4n-6) biosynthesis in Daphnia magna. Neonates of D. magna were maintained on [(13)C] enriched Scenedesmus obliquus and supplemented with liposomes that contained separate treatments of unlabeled docosapentaenoic acid (22:5n-6), 20:4n-6, linoleic acid (18:2n-6) or oleic acid (18:1n-9). Daphnia in the control treatment, without any supplementary fatty acids (FA) containing only trace amounts of 20:4n-6 (~0.3% of all FA). As expected, the highest proportion of 20:4n-6 (~6.3%) was detected in Daphnia that received liposomes supplemented with this FA. Higher availability of 18:2n-6 in the diet increased the proportion of 18:2n-6 in Daphnia, but the proportion of 20:4n-6 was not affected. Daphnia supplemented with 22:5n-6 contained ~3.5% 20:4n-6 in the lipids and FA specific stable isotope analyses validated that the increase in the proportion of 20:4n-6 was due to retroconversion of unlabeled 22:5n-6. These results suggest that chain shortening of 22:5n-6 is a more efficient pathway to synthesize 20:4n-6 in D. magna than elongation and desaturation of 18:2n-6. These results may at least partially explain the discrepancies noticed between phytoplankton FA composition and the expected FA composition in freshwater cladocerans. Finally, retroconversion of dietary 22:5n-6 to 20:4n-6 indicates Daphnia efficiently retain long chain n-6 FA in lake food webs, which might be important for the nutritional ecology of fish.

  20. Bioconcentration of the antidepressant fluoxetine and its effects on the physiological and biochemical status in Daphnia magna.

    Science.gov (United States)

    Ding, Jiannan; Zou, Hua; Liu, Qingqing; Zhang, Shanshan; Mamitiana Razanajatovo, Roger

    2017-08-01

    The aim of this study was to evaluate the bioconcentration potential of fluoxetine and its biological effects in Daphnia magna. After 48h of waterborne exposure, the bioconcentration of fluoxetine in D. magna was determined to be 460.61 and 174.41Lkg(-1) for nominal exposure concentrations of 0.5 and 5µgL(-1), respectively. Moreover, various biological endpoints, including physiological responses (filtration and ingestion rates), enzymatic biomarkers related to neurotoxicity [acetylcholinesterase (AChE)] and antioxidant defense [superoxide dismutase (SOD)], and an oxidative stress damage marker [malondialdehyde (MDA)], were assessed. Fluoxetine exposure increased the filtration rate of daphnia, while the ingestion rate was not obviously modified. AChE activity was significantly inhibited, highlighting the neurotoxicity of fluoxetine on D. magna. However, with some alterations in the SOD activity and MDA content, no obvious oxidative damage was observed in D. magna exposed to fluoxetine at the tested concentrations. These results indicate that fluoxetine can be accumulated and consequently induce physiological and biochemical perturbations in D. magna. Copyright © 2017. Published by Elsevier Inc.

  1. Growth of Daphnia magna males and females fed with the cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus obliquus in different proportions

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Beekman, W.

    2006-01-01

    Laboratory experiments were used to study the sensitivity of both male and female Daphnia magna to a toxic cyanobacterium, Microcystis aeruginosa. Male and female D. magna were fed with M. aeruginosa and a green alga (Scenedesmus obliquus) in different mixtures that included 0%, 25%, 50%, 75% and 10

  2. Effects of the cyanobacterial neurotoxin B-N-methylamino-L-alamine (BMAA) on the survival, mobility and reproduction of Daphnia magna

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Faassen, E.J.; Eenennaam, van J.S.

    2011-01-01

    In short-term tests and chronic life table assays, Daphnia magna was exposed to the cyanobacterial neurotoxic non-protein amino acid ß-N-methylamino-l-alanine (BMAA). BMAA was not acutely lethal to Daphnia (LC50–48h > 10 000 µg L-1), but reduced mobility (IC50–48h 40 µg L-1) and affected life his

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  5. Acute toxicity bioassays using Daphnia magna Straus (Cladocera, Daphniidae maintained in a modified culture medium

    Directory of Open Access Journals (Sweden)

    Mónica Núñez

    2013-05-01

    Full Text Available Daphnia magna is a test organism used in ecotoxicological assays of freshwater; however, traditional culture systems for this organism could result expensive, for that the aim of this research was to developed a new economic culture medium. With this purpose, 10 strains of D. magna were isolated, their population development was evaluated by total count of organisms and pregnant females using 3 different culture media: (A alfalfa juice, (B solved yeast and (C a mixture of alfalfa juice plus solved yeast. Successful development of 4 strains was observed in the A medium, but the same strains failed to survive in the B and the C media. The 24h and 48h EC50 average values in acute ecotoxicological assays with potassium dicromate were 0,4045 mg/L ± 0,0389 and 0,1857 mg/L ± 0,0072 respectively. Also, acute ecotoxicological assays with these 4 strains were performed using potassium cyanide, which is a toxic reactive frequently used in mining operations. In this case 24h EC50 value was 1,5388 mg/L ± 0,1146 and 48h EC50 values were 0,6359 mg/L ± 0,0516. 48h EC50 values were lower than the cyanide permissible effluent values established by the Energy and Mining Authority.

  6. Genetic estimates of population age in the water flea, Daphnia magna.

    Science.gov (United States)

    Robinson, John D; Haag, Christoph R; Hall, David W; Pajunen, V Ilmari; Wares, John P

    2012-01-01

    Genetic datasets can be used to date evolutionary events, even on recent time scales if sufficient data are available. We used statistics calculated from multilocus microsatellite datasets to estimate population ages in data generated through coalescent simulations and in samples from populations of known age in a metapopulation of Daphnia magna in Finland. Our simulation results show that age estimates improve with additional loci and define a time frame over which these statistics are most useful. On the most recent time scales, assumptions regarding the model of mutation (infinite sites vs. stepwise mutation) have little influence on estimated ages. In older populations, size homoplasy among microsatellite alleles results in a downwards bias for estimates based on the infinite sites model (ISM). In the Finnish D. magna metapopulation, our genetically derived estimated ages were biased upwards. Potential sources of this bias include the underlying model of mutation, gene flow, founder size, and the possibility of persistent source populations in the system. Our simulated data show that genetic age estimation is possible, even for very young populations, but our empirical data highlight the importance of factors such as migration when these statistics are applied in natural populations.

  7. Microscopic investigation of single-wall carbon nanotube uptake by Daphnia magna.

    Science.gov (United States)

    Edgington, Aaron James; Petersen, Elijah J; Herzing, Andrew A; Podila, Ramakrishna; Rao, Apparao; Klaine, Stephen J

    2014-08-01

    The objectives of this study were to determine the extent of absorption of functionalized single-wall carbon nanotubes (SWCNTs) across the gut epithelial cells in Daphnia magna. Several microscopic techniques were utilized, including micro-Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and selective area diffraction (SAD). In an effort to examine the variation in uptake due to surface properties, four groups of differently functionalized SWCNTs were used: hydroxylated (OH-SWCNTs), silicon dioxide (SiO2-SWCNTs), poly aminobenzenesulfonic acid (PABS-SWCNTs) and polyethylene glycol (PEG-SWCNTs). Raman spectroscopy was able to detect OH-SWCNTs within the gut, but lacked the spatial resolution that is needed to identify lower concentrations of SWCNTs that may have been absorbed by body tissues. Initially, low-magnification imaging of exposed D. magna sections in the TEM revealed several features, which suggested absorption of SWCNTs. However, subsequent analysis with additional techniques (HRTEM, X-ray energy-dispersive spectroscopy and SAD) indicated that these features were either artifacts produced via the specimen staining process or consisted of non-graphitic, organic structures. This latter observation emphasizes the inherent difficulty in resolving SWCNTs embedded within a complex, organic matrix, as well as the care with which imaging results must be interpreted and supplemented with other, more analytical techniques.

  8. Effect of carbaryl (carbamate insecticide) on acetylcholinesterase activity of two strains of Daphnia magna (Crustacea, Cladocera).

    Science.gov (United States)

    Toumi, Hela; Bejaoui, Mustapha; Touaylia, Samir; Burga Perez, Karen F; Ferard, Jean François

    2016-11-01

    The present study was designed to investigate the effect of carbaryl (carbamate insecticide) on the acetylcholinesterase activity in two strains (same clone A) of the crustacean cladoceran Daphnia magna. Four carbaryl concentrations (0.4, 0.9, 1.8 and 3.7 µg L(-1)) were compared against control AChE activity. Our results showed that after 48 h of carbaryl exposure, all treatments induced a significant decrease of AChE activities whatever the two considered strains. However, different responses were registered in terms of lowest observed effect concentrations (LOEC: 0.4 µg L(-1) for strain 1 and 0.9 µg L(-1) for strains 2) revealing differences in sensitivity among the two tested strains of D. magna. These results suggest that after carbaryl exposure, the AChE activity responses can be also used as a biomarker of susceptibility. Moreover, our results show that strain1 is less sensitive than strain 2 in terms of IC50-48 h of AChE activity. Comparing the EC50-48 h of standard ecotoxicity test and IC50-48 h of AChE inhibition, there is the same order of sensitivity with both strains.

  9. EFFECT OF A BIODEGRADABLE DETERGENT IN WATER ON DAPHNIA MAGNA REPRODUCTION

    Directory of Open Access Journals (Sweden)

    Castiglioni, M

    2010-01-01

    Full Text Available The aquatic ecosystems near to urban zone have a constant risk by several physical and chemical factors relative to human activities. This provokes synergic effects on aquatic organisms, being the domestic sewage an important factor to assess, highlighting the detergents. The cladocerans Daphnia magna, there is not originate in the Neotropical region, is a specie more used in ecotoxicological assays in the world by its easy culture and short life cycle. The aim of the work is observe as affect the commercial detergent on D. magna and their reproductive fitness. This was realized with chronic assays of isolated and grouped individuals using three sublethal concentrations of anionic detergent, previously the C was determined. The assays lasted 21 days, daily the 50 neonates were registered. These were counted and measured. In the chronic assays, the isolated individuals produced 262 embryos in the control group, being alike to two lower concentrations. The neonates were more abundant in the higher concentration than in lower and control ones. In the grouped animal experience, the increase in the egg number was progressive to detergent concentration. In this study, the detergent could be induced a production of more abundant and viable offspring. This could be associated with that the detergent permit an effective use of trophic resource and bioavailability of energy to reproduction, when the detergent discharge breaks down the particles or algal cells offered as food.

  10. Effect of deltamethrin (pyrethroid insecticide) on two clones of Daphnia magna (Crustacea, Cladocera): a proteomic investigation.

    Science.gov (United States)

    Toumi, Héla; Boumaiza, Moncef; Immel, Françoise; Sohm, Bénédicte; Felten, Vincent; Férard, Jean-François

    2014-03-01

    Deltamethrin is a class II pyrethroid insecticide commonly used in agriculture. It is hazardous to freshwater ecosystems, especially for the cladoceran Daphnia magna (Straus 1820). The results of our previous studies based on acute and chronic ecotoxicity experiments revealed differences in the sensitivity between two different clones. In this work, to investigate deltamethrin toxicity mechanisms in two clones of D. magna, we used a proteomic approach in order to analyze changes in protein expression profiles after 48 h of exposure. We detected 1339 spots; then applying statistical criteria (ANOVA pclones. Moreover, using the 2-DIGE method, proteomic investigation for deltamethrin exposure proved to be a reliable and powerful approach to investigate effects of deltamethrin as part of research for new metabolic and cellular biomarkers. After identification by mass spectrometry, there were 39 proteins recognized and identified, in which 21 and 18 were up- and down-regulated, respectively, in deltamethrin-exposed clone A compared to three other conditions (controls of each clone and deltamethrin-exposed clone 2). Up- and down-regulated proteins belonged to 12 biological processes (i.e. metabolic processes, apoptosis and stimulus response) and 5 molecular functions (i.e. catalytic activity, binding, structural molecular activity, antioxidant and receptor activities). Identification of these deregulated proteins opens a new way in discovering new molecular targets and putative biomarkers in daphnids exposed to deltamethrin.

  11. Thresholds for sterol-limited growth of Daphnia magna: a comparative approach using 10 different sterols.

    Science.gov (United States)

    Martin-Creuzburg, Dominik; Oexle, Sarah; Wacker, Alexander

    2014-09-01

    Arthropods are incapable of synthesizing sterols de novo and thus require a dietary source to cover their physiological demands. The most prominent sterol in animal tissues is cholesterol, which is an indispensable structural component of cell membranes and serves as precursor for steroid hormones. Instead of cholesterol, plants and algae contain a variety of different phytosterols. Consequently, herbivorous arthropods have to metabolize dietary phytosterols to cholesterol to meet their requirements for growth and reproduction. Here, we investigated sterol-limited growth responses of the freshwater herbivore Daphnia magna by supplementing a sterol-free diet with increasing amounts of 10 different phytosterols and comparing thresholds for sterol-limited growth. In addition, we analyzed the sterol composition of D. magna to explore sterol metabolic constraints and bioconversion capacities. We show that dietary phytosterols strongly differ in their potential to support somatic growth of D. magna. The dietary threshold concentrations obtained by supplementing the different sterols cover a wide range (3.5-34.4 μg mg C(-1)) and encompass the one for cholesterol (8.9 μg mg C(-1)), indicating that certain phytosterols are more efficient in supporting somatic growth than cholesterol (e.g., fucosterol, brassicasterol) while others are less efficient (e.g., dihydrocholesterol, lathosterol). The dietary sterol concentration gradients revealed that the poor quality of particular sterols can be alleviated partially by increasing dietary concentrations, and that qualitative differences among sterols are most pronounced at low to moderate dietary concentrations. We infer that the dietary sterol composition has to be considered in zooplankton nutritional ecology to accurately assess potential sterol limitations under field conditions.

  12. Mechanistic study of the toxicity of ionizing radiation in Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, F.; Alonzo, F. [Institut de Radioprotection et de Surete Nucleaire, IRSN/PRP-ENV/SERIS/LECO, Laboratoire d' Ecotoxicologie des Radionucleides, Cadarache (France); Bourdineaud, J.P. [UMR CNRS 5805 EPOC - OASU Station Marine d' Arcachon Universite Bordeaux 1, Arcachon (France); Poggiale, J.C. [Mediterranean Institute of Oceanography - MIO - UMR 7294 Pytheas Institute - OSU, Aix-Marseille University, Marseille (France)

    2014-07-01

    In the last decade, the ecological impact of ionizing radiation has emerged as a growing scientific concern for ecosystems protection. However, the assessment of potential radiological effects on the environment is hampered by both a gap of available scientific data and a lack in proven methods. Understanding how ionizing radiation affects wildlife at biologically and ecologically relevant scales is a major issue in environmental protection. This issue is one of the objectives of the Strategic Research Agenda (SRA) developed in the framework of the European program STAR (Strategy for Allied Radioecology). In this context, the present PhD project aims to evaluate chronic effects of external Cs-137 gamma radiation at low doses on a representative species of aquatic ecosystems, the cladoceran crustacean Daphnia magna. More precisely, the objectives of this study are to evaluate multi-generational effects of irradiation on: (i) genotoxic effects and their potential consequences on survival, somatic growth and fecundity, (ii) the energy budget and (iii) the population dynamics of Daphnia. An experimental design was developed to expose daphnids to low doses of ionizing radiation ranging from 0,008 to 32 mGy.h{sup -1} across 3 successive generations (75 days). DNA damages were assessed using random amplified polymorphic DNA and real time PCR (RAPD - PCR). Effects on survival, somatic growth and fecundity were monitored for 21-25 days in each generation, from hatching to release of brood 5. Our aim is to: examine a potential correlation between molecular (DNA) damage and effects observed at the individual level (survival, somatic growth and fecundity) across generations and test the suitability of DNA damage as an early indice of future trans-generational effects. As a future perspective, individual and molecular effects data will be analysed using a DEBtox model (Dynamic Energy Budget Applied to Toxicology) in order to identify the metabolic modes of action of ionizing

  13. Enrichment of Daphnia magna with Canola Oil and its Effects on the Growth, Survival and Stress Resistance of the Caspian Kutum (Rutilus frisii kutum) Larvae

    OpenAIRE

    Fereidouni, Abolghasem Esmaeili; Fathi, Neda; Khalesi, Mohammad Kazem

    2013-01-01

    In freshwater larviculture, Daphnia species have received considerable attention as live food. This study examined the use of canola oil to enrich Daphnia magna as a function of enrichment duration. The experiment compared four enrichment durations (3, 6, 9, and 12 h) with a non-enriched control group. An enrichment time up to 6 h resulted in the highest amounts of polyunsaturated fatty acids (PUFAs) in the fatty acid profile of D. magna. Afterward, D. magna enriched within 6 h was fed to...

  14. Uncovering Ultrastructural Defences in Daphnia magna – An Interdisciplinary Approach to Assess the Predator-Induced Fortification of the Carapace

    OpenAIRE

    2013-01-01

    The development of structural defences, such as the fortification of shells or exoskeletons, is a widespread strategy to reduce predator attack efficiency. In unpredictable environments these defences may be more pronounced in the presence of a predator. The cladoceran Daphnia magna (Crustacea: Branchiopoda: Cladocera) has been shown to develop a bulky morphotype as an effective inducible morphological defence against the predatory tadpole shrimp Triops cancriformis (Crustacea: Branchiopoda: ...

  15. Nano-TiO{sub 2} enhances the toxicity of copper in natural water to Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Fan Wenhong, E-mail: fanwh@buaa.edu.cn [Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Cui Minming [Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Liu Hong; Wang Chuan [Research Center for Green Chemistry and Engineering, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Shi Zhiwei; Tan Cheng; Yang Xiuping [Department of Environmental Science and Engineering, School of Chemistry and Environment, Beihang University, Beijing 100191 (China)

    2011-03-15

    The acute toxicity of engineered nanoparticles (NPs) in aquatic environments at high concentrations has been well-established. This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO{sub 2} remarkably enhanced the toxicity of copper to Daphnia magna by increasing the copper bioaccumulation. Specifically, at 2 mg L{sup -1} nano-TiO{sub 2}, the (LC{sub 50}) of Cu{sup 2+} concentration observed to kill half the population, decreased from 111 {mu}g L{sup -1} to 42 {mu}g L{sup -1}. Correspondingly, the level of metallothionein decreased from 135 {mu}g g{sup -1} wet weight to 99 {mu}g g{sup -1} wet weight at a Cu{sup 2+} level of 100 {mu}g L{sup -1}. The copper was found to be adsorbed onto the nano-TiO{sub 2}, and ingested and accumulated in the animals, thereby causing toxic injury. The nano-TiO{sub 2} may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification by metallothioneins. - Research highlights: > This study demonstrates that, at a concentration generally considered to be safe in the environment, nano-TiO{sub 2} remarkably enhanced the toxicity of copper to Daphnia magna. > The copper was found to be adsorbed onto the nano-TiO{sub 2}, and ingested and accumulated in the Daphnia magna, thereby causing toxic injury. > The nano-TiO{sub 2} may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification mechanism of metallothionein. - The nano-TiO{sub 2} remarkably enhanced the toxicity of copper to Daphnia magna. The nano-TiO{sub 2} may compete for free copper ions with sulfhydryl groups, causing the inhibition of the detoxification mechanism of metallothionein.

  16. The water flea (Daphnia magna) as a sensitive indicator for the assessment of toxicity of synthetic detergents.

    Science.gov (United States)

    Lal, H; Misra, V; Viswanathan, P N; Murti, C R

    1984-10-01

    The water flea (Daphnia magna) was used as a sensitive indicator for assessing the toxicity due to synthetic detergents. Acute and chronic toxicity of detergents to the water flea was studied under laboratory conditions by following the median tolerance limit (TLM) at 48 hr and the rate of survival. A significant decrease in the rate of reproduction (number of hatching and neonates produced) were found at 21 days. During acute toxicity studies behavioural changes were also noticed.

  17. Exposure of Daphnia magna to trichloroethylene (TCE) and vinyl chloride (VC): evaluation of gene transcription, cellular activity, and life-history parameters.

    Science.gov (United States)

    Houde, Magali; Douville, Mélanie; Gagnon, Pierre; Sproull, Jim; Cloutier, François

    2015-06-01

    Trichloroethylene (TCE) is a ubiquitous contaminant classified as a human carcinogen. Vinyl chloride (VC) is primarily used to manufacture polyvinyl chloride and can also be a degradation product of TCE. Very few data exist on the toxicity of TCE and VC in aquatic organisms particularly at environmentally relevant concentrations. The aim of this study was to evaluate the sub-lethal effects (10 day exposure; 0.1; 1; 10 µg/L) of TCE and VC in Daphnia magna at the gene, cellular, and life-history levels. Results indicated impacts of VC on the regulation of genes related to glutathione-S-transferase (GST), juvenile hormone esterase (JHE), and the vitelline outer layer membrane protein (VMO1). On the cellular level, exposure to 0.1, 1, and 10 µg/L of VC significantly increased the activity of JHE in D. magna and TCE increased the activity of chitinase (at 1 and 10 µg/L). Results for life-history parameters indicated a possible tendency of TCE to affect the number of molts at the individual level in D. magna (p=0.051). Measurement of VG-like proteins using the alkali-labile phosphates (ALP) assay did not show differences between TCE treated organisms and controls. However, semi-quantitative measurement using gradient gel electrophoresis (213-218 kDa) indicated significant decrease in VG-like protein levels following exposure to TCE at all three concentrations. Overall, results indicate effects of TCE and VC on genes and proteins related to metabolism, reproduction, and growth in D. magna.

  18. Effect of temperature on chronic toxicity of copper, zinc, and nickel to Daphnia magna.

    Science.gov (United States)

    Pereira, Cecília M S; Deruytter, David; Blust, Ronny; De Schamphelaere, Karel A C

    2017-07-01

    Few studies have considered the effect of temperature on the chronic sensitivity of Daphnia magna to other stressors. The present study investigated the effect of temperature on chronic metal toxicity and whether this effect differed among 4 different D. magna clones. Life table experiments were performed with copper, zinc, and nickel at 15 °C, 20 °C, and 25 °C. General linear modeling indicated that chronic Cu, Zn, and Ni toxicity to D. magna were all significantly affected by temperature. When averaged across clones, our results suggest that chronic metal toxicity to D. magna was higher at 15 °C than at 20 °C, which is the temperature used in standard toxicity tests. At 15 °C, the 21-d median effect concentrations (EC50s) of Cu, Zn, and Ni were 1.4 times, 1.1 times, and 1.3 times lower than at 20 °C, respectively. At 25 °C, chronic Cu and Zn toxicity did not change in comparison with 20 °C, but chronic Ni toxicity was lower (21-d EC50 of nickel at 25 °C was 1.6 times higher than at 20 °C). The same trends were observed for Cu and Ni when the 21-d 10% and 20% effect concentrations were considered as the effect estimator, but not for Zn, which warns against extrapolating temperature effects on chemical toxicity across effect sizes. Overall, however, chronic metal toxicity was generally highest at the lowest temperature investigated (15 °C), which is in contrast with the usually observed higher acute metal toxicity at higher temperatures. Furthermore, the effect of temperature on chronic Ni toxicity depended significantly on the clone. This warns against extrapolating results about effect of temperature on chemical toxicity from single clone studies to the population level. Environ Toxicol Chem 2017;36:1909-1916. © 2016 SETAC. © 2016 SETAC.

  19. The potential of dietary polyunsaturated fatty acids to modulate eicosanoid synthesis and reproduction in Daphnia magna: a gene expression approach.

    Science.gov (United States)

    Schlotz, Nina; Sørensen, Jesper Givskov; Martin-Creuzburg, Dominik

    2012-08-01

    Nutritional ecology of the aquatic model genus Daphnia has received much attention in past years in particular with regard to dietary polyunsaturated fatty acids (PUFAs) which are crucial for growth and reproduction. Besides their significant role as membrane components, C20 PUFAs serve as precursors for eicosanoids, hormone-like mediators of reproduction, immunity and ion transport physiology. In the present study we investigate transcriptomic changes in Daphnia magna in response to different algal food organisms substantially differing in their PUFA composition using quantitative real-time PCR and relate them to concomitantly documented life history data. The selection of target genes includes representatives that have previously been shown to be responsive to the eicosanoid biosynthesis inhibitor ibuprofen. The beneficial effect of C20 PUFA-rich food on reproduction and population growth rates was accompanied by an increased vitellogenin (DmagVtg1) gene expression in D. magna. Additionally, genes involved in eicosanoid signaling were particularly influenced by dietary C20 PUFA availability. For example, the cyclooxygenase gene (Cox), coding for a central enzyme in the eicosanoid pathway, was highly responsive to the food treatments. Our results suggest that dietary PUFAs are fundamental in D. magna physiology as substrate for eicosanoid synthesis and that these eicosanoids are important for D. magna reproduction.

  20. X-ray and electron microscopy studies on the biodistribution and biomodification of iron oxide nanoparticles in Daphnia magna.

    Science.gov (United States)

    Kwon, Dongwook; Nho, Hyun Woo; Yoon, Tae Hyun

    2014-10-01

    Biodistribution and biomodification of iron oxide (Fe3O4 and α-Fe2O3) nanoparticles (NPs) in a well-known toxicity test organism, Daphnia magna (D. magna), were investigated using transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM). In addition to the morphological changes in the gut tissues of D. magna, biodistribution and biomodification of iron oxide NPs in the digestive tract of D. magna were also monitored in this study. Upon exposures to both iron oxide NPs, unique morphological changes (e.g., irregular shaped microvilli, epithelial cell protrusion, and dilatation of cytoplasmic inclusion) in the gut tissues of D. magna were observed along with bacterial colonization of the gut lumen. However, despite their heavy accumulations in the digesitive tract, TEM and STXM images confirmed us that both Fe3O4 and α-Fe2O3 NPs were not penetrating into the gut tissues of D. magna. Moreover, for the Fe3O4 NPs in direct contact with the gut microvilli of D. magna, slight but significant spectral changes were observed in their Fe L-edge X-ray absorption near edge structure (XANES) spectra, which indicated that there were biomodifications of Fe3O4 NPs, probably involving oxidative dissolution of Fe3O4 NPs followed by rapid precipitation of ferric oxide or hydroxide. However, no significant changes were observed in the Fe L-edge XANES spectra of the α-Fe2O3 NPs present in the gut lumen of D. magna. These X-ray and electron microscopic observations confirmed us that, despite similarities in core sizes and chemical compositions, NPs with different crystalline phase and dissolution rates can interact quite differently with their local environment, may result in different biodistribution and cause completely dissimilar toxicities.

  1. Bioaccumulation and biotransformation of the beta-blocker propranolol in multigenerational exposure to Daphnia magna.

    Science.gov (United States)

    Jeong, Tae-Yong; Kim, Tae-Hun; Kim, Sang Don

    2016-09-01

    Multigenerational bioaccumulation and biotransformation activity and short-term kinetics (e.g., uptake and depuration) of propranolol in Daphnia magna were investigated at environmental concentration. The body burden and the major metabolite, desisopropyl propranolol (DIP), of propranolol were quantified using LC-MS/MS at the end of each generation after exposure for 11 generations. The accumulation of propranolol in D. magna at an environmental concentration of 0.2 μg/L was not much different between the parent (F0) and the eleventh filial (F10) generation. However, at 28 μg/L, its accumulation was 1.6 times higher-up to 18.9 μg/g-in the F10 generation relative to the F0. In contrast to propranolol, DIP intensity gradually increased from F0 to F10 at 0.2 μg/L, reflecting an increase in detoxification load and biotransformation performance; no increasing trend was observed at 28 μg/L. The bioaccumulation factor (BAF) showed higher values with a lower concentration and longer period of exposure. The average values of the BAF for 21 days of long-term exposure in successive 11 generations were 440.4 ± 119.7 and 1026.5 ± 208.6 L/kg for 28 μg/L and 0.2 μg/L, respectively. These are comparable to the BAF of 192 for the short-term 72-h exposure at 28 μg/L in the parent generation. It is also recommended that future studies for pharmaceutical ingredients be conducted on drug-drug interaction and structural characteristics on the prediction of biotransformation activity and bioaccumulation rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Behavior and chronic toxicity of two differently stabilized silver nanoparticles to Daphnia magna.

    Science.gov (United States)

    Sakka, Yvonne; Skjolding, Lars Michael; Mackevica, Aiga; Filser, Juliane; Baun, Anders

    2016-08-01

    While differences in silver nanoparticle (AgNP) colloidal stability, surface potential, or acute aquatic toxicity for differently stabilized AgNP have often been reported, these have rarely been studied in long-term ecotoxicity tests. In the current study, we investigated the chronic toxicity of AgNP to Daphnia magna over a 21-day period with two different stabilizers (citrate and detergent), representative for charge and sterical stabilizers, respectively. This was coupled with a series of short-term experiments, such as mass balance and uptake/depuration testing, to investigate the behavior of both types of AgNP during a typical media exchange period in the D. magna test for chronic toxicity. As expected, the sterically stabilized AgNP was more stable in the test medium, also in the presence of food; however, a higher uptake of silver after 24h exposure of the charge stabilized AgNP was found compared to the detergent-stabilized AgNP (0.046±0.006μgAgμgDW(-1) and 0.023±0.005μgAgμgDW(-1), respectively). In accordance with this, the higher reproductive effects and mortality were found for the charge-stabilized than for the sterically-stabilized silver nanoparticles in 21-d tests for chronic toxicity. LOEC was 19.2μgAgL(-1) for both endpoints for citrate-coated AgNP and >27.5μgAgL(-1) (highest tested concentration for detergent-stabilized AgNP). This indicates a link between uptake and toxicity. The inclusion of additional short-term experiments on uptake and depuration is recommended when longer-term chronic experiments with nanoparticles are conducted.

  3. Filming of zooplankton: a case study of rotifer males and Daphnia magna

    Directory of Open Access Journals (Sweden)

    Pierluigi Colangeli

    2015-11-01

    Full Text Available Filming live organisms can give new insights into the hidden life of plankton. Accessibly priced digital cameras are now available for a large range of users. Here, we demonstrate the technical setup and workflow of using a single-lens reflex (DSLR camera to film the behaviour of males of two rotifer species, Brachionus angularis Gosse (1851 and Keratella cochlearis Gosse (1851, and of the cladoceran Daphnia magna Straus (1820. Rotifers are cyclical parthenogens that produce males only under certain environmental conditions. Thus, knowledge on rotifer males is still limited because of their ephemeral nature and because they are often smaller than females. We filmed males of B. angularis and K. cochlearis with a DSLR camera connected to a compound microscope to better understand their morphology and behaviour in comparison to conspecific females. While written descriptions have their scientific value, seeing is complementary because everyone can verify what has been described. We made our videos publicly accessible through links connected to the paper. Our videos are, to our best knowledge, the first on males of B. angularis and K. cochlearis. Furthermore, we filmed the behavioural response of D. magna to ultraviolet (UV radiation with a macro lens attached to the DSLR camera. Approaches like this are valuable tools in environmental teaching. To see live organisms with one’s own eyes may contribute to raising public awareness about the value of water resources and their hidden communities. In summary, filming can be a valuable tool to ignite scientific discussion, but the videos need an open-access platform where they can be referenced in a topic-related order.

  4. Photo-induced toxicity of titanium dioxide nanoparticles to Daphnia magna under natural sunlight.

    Science.gov (United States)

    Mansfield, C M; Alloy, M M; Hamilton, J; Verbeck, G F; Newton, K; Klaine, S J; Roberts, A P

    2015-02-01

    Titanium dioxide nanoparticles (TiO2 NP) are one of the most abundantly utilized nanoparticles in the world. Studies have demonstrated the ability of the anatase crystal of TiO2 NP to produce reactive oxygen species (ROS) in the presence of ultraviolet radiation (UVR), a co-exposure likely to occur in aquatic ecosystems. The goal of this study was to examine the photo-induced toxicity of anatase TiO2 NP under natural sunlight to Daphnia magna. D. magna were exposed to a range of UVR intensities and anatase TiO2 concentrations in an outdoor exposure system using the sun as the source of UVR. Different UVR intensities were achieved using UVR opaque and transparent plastics. AnataseTiO2-NP demonstrated the reciprocal relationship seen in other phototoxic compounds such as polycyclic aromatic hydrocarbons (PAHs) at higher UVR treatments. The calculated 8h LC50 of anatase TiO2 NP was 139 ppb under full intensity ambient natural sunlight, 778 ppb under 50% natural sunlight, and >500 ppm under 10% natural sunlight. Mortality was also compared between animals allowed to accumulate a body burden of anatase TiO2 for 1h and organisms whose first exposure to anatase TiO2 aqueous suspensions occurred under UVR. A significantly greater toxic effect was observed in aqueous, low body burden suspensions than that of TiO2 1h body burdens, which is dissimilar from the model presented in PAHs. Anatase TiO2 presents a unique photo-induced toxic model that is different than that of established phototoxic compounds.

  5. Heterodimeric TALENs induce targeted heritable mutations in the crustacean Daphnia magna

    Directory of Open Access Journals (Sweden)

    Akiko Naitou

    2015-02-01

    Full Text Available Transcription activator-like effector nucleases (TALENs are artificial nucleases harboring a customizable DNA-binding domain and a FokI nuclease domain. The high specificity of the DNA-binding domain and the ease of design have enabled researchers to use TALENs for targeted mutagenesis in various organisms. Here, we report the development of TALEN-dependent targeted gene disruption in the crustacean Daphnia magna, the emerging model for ecological and toxicological genomics. First, a reporter transgene DsRed2 (EF1α-1::DsRed2 was targeted. Using the Golden Gate method with a GoldyTALEN scaffold, we constructed homodimeric and heterodimeric TALENs containing wild-type and ELD/KKR FokI domains. mRNAs that coded for either the customized homodimeric or heterodimeric TALENs were injected into one-cell-stage embryos. The high mortality of embryos injected with homodimeric TALEN mRNAs prevented us from detecting mutations. In contrast, embryos injected with heterodimeric TALEN mRNAs survived and 78%–87% of the adults lost DsRed2 fluorescence in a large portion of cells throughout the body. In addition, these adults produced non-fluorescent progenies, all of which carried mutations at the dsRed2 locus. We also tested heterodimeric TALENs targeted for the endogenous eyeless gene and found that biallelic mutations could be transmitted through germ line cells at a rate of up to 22%. Both somatic and heritable mutagenesis efficiencies of TALENs were higher than those of the CRISPR/Cas9 system that we recently developed. These results suggest that the TALEN system may efficiently induce heritable mutations into the target genes, which will further contribute to the progress of functional genomics in D. magna.

  6. Heterodimeric TALENs induce targeted heritable mutations in the crustacean Daphnia magna.

    Science.gov (United States)

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

    2015-02-13

    Transcription activator-like effector nucleases (TALENs) are artificial nucleases harboring a customizable DNA-binding domain and a FokI nuclease domain. The high specificity of the DNA-binding domain and the ease of design have enabled researchers to use TALENs for targeted mutagenesis in various organisms. Here, we report the development of TALEN-dependent targeted gene disruption in the crustacean Daphnia magna, the emerging model for ecological and toxicological genomics. First, a reporter transgene DsRed2 (EF1α-1::DsRed2) was targeted. Using the Golden Gate method with a GoldyTALEN scaffold, we constructed homodimeric and heterodimeric TALENs containing wild-type and ELD/KKR FokI domains. mRNAs that coded for either the customized homodimeric or heterodimeric TALENs were injected into one-cell-stage embryos. The high mortality of embryos injected with homodimeric TALEN mRNAs prevented us from detecting mutations. In contrast, embryos injected with heterodimeric TALEN mRNAs survived and 78%-87% of the adults lost DsRed2 fluorescence in a large portion of cells throughout the body. In addition, these adults produced non-fluorescent progenies, all of which carried mutations at the dsRed2 locus. We also tested heterodimeric TALENs targeted for the endogenous eyeless gene and found that biallelic mutations could be transmitted through germ line cells at a rate of up to 22%. Both somatic and heritable mutagenesis efficiencies of TALENs were higher than those of the CRISPR/Cas9 system that we recently developed. These results suggest that the TALEN system may efficiently induce heritable mutations into the target genes, which will further contribute to the progress of functional genomics in D. magna.

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

    Science.gov (United States)

    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 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. Copyright © 2015 John Wiley & Sons, Ltd.

  8. Chronic toxicity of 14 phthalate esters to Daphnia magna and rainbow trout (Oncorhynchus mykiss)

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, J.E.; Adams, W.J. [ABC Labs., Inc., Columbia, MO (United States); Biddinger, G.R. [Exxon Biomedical Sciences Inc., Benecia, CA (United States); Robillard, K.A.; Gorsuch, J.W. [Eastman Kodak Co., Rochester, NY (United States)

    1995-11-01

    Chronic toxicity studies were performed with commercial phthalate esters and Daphnia magna (14 phthalates) and rainbow trout (Oncorhynchus mykiss) (six phthalates). For the lower-molecular-weight phthalate esters--dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and butylbenzyl phthalate (BBP)--the results of the studies indicated a general trend in which toxicity for both species increased as water solubility decreased. The geometric mean maximum acceptable toxicant concentration(GM-MATC) for D. magna ranged from 0.63 to 34.8 mg/L. For the higher-molecular-weight phthalate esters--dihexyl phthalate (DHP), butyl 2-ethylhexyl phthalate (BOP), di-(n-hexyl, n-octyl, n-decyl) phthalate (610P), di-(2-ethylhexyl) phthalate (DEHP), diisooctyl phthalate (DIOP), diisononyl phthalate (DINP), di-(heptyl, nonyl, undecyl) phthalate (711P), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), and ditridecyl phthalate (DTDP)--the GM-MATC values ranged from 0.042 to 0.15 mg/L. Survival was equally sensitive and sometimes more sensitive than reproduction. The observed toxicity to daphnids with most of the higher-molecular-weight phthalate esters appeared to be due to surface entrapment or a mode of toxicity that is not due to exposure to dissolved aqueous-phase chemical. Early life-stage toxicity studies with rainbow trout indicated that survival (DMP) and growth (DBP) were affected at 24 and 0.19 mg/L, respectively. This pattern of observed toxicity with the lower-molecular-weight phthalate esters and not the higher-molecular-weight phthalate esters is consistent with previously reported acute toxicity studies for several aquatic species.

  9. Toxicity and genotoxicity of the quaternary ammonium compound benzalkonium chloride (BAC) using Daphnia magna and Ceriodaphnia dubia as model systems.

    Science.gov (United States)

    Lavorgna, Margherita; Russo, Chiara; D'Abrosca, Brigida; Parrella, Alfredo; Isidori, Marina

    2016-03-01

    The toxicity and genotoxicity of the cationic surfactant benzalkonium chloride (BAC) were studied using Daphnia magna and Ceriodaphnia dubia as model systems. Acute and chronic toxicity testing were performed according to the international standard guidelines and the genotoxicity was detected through the comet assay on cells from whole organisms in vivo exposed. Acute effects occurred at concentrations in the order of tens of μg/L in D. magna and hundreds of μg/L in C. dubia. Chronic effects were found at one order of magnitude less than short-term effects maintaining the same difference in sensitivity between D. magna and C. dubia. BAC induced relevant DNA damage, in both cladocerans; the lowest adverse effect levels were 0.4 and 4 ng/L for D. magna and C. dubia, respectively. As these effective concentrations are far lower than BAC occurrence in surface waters (units of μg/L) a concerning environmental risk cannot be excluded. The findings of this study showed that D. magna and C. dubia, could be used as model organisms to detect acute and chronic toxicity as well as genotoxicity at the whole organism level.

  10. The effects of Amax yeast fed to Persian sturgeon (Acipencer persicus larvae via bioenrichment of Daphnia magna

    Directory of Open Access Journals (Sweden)

    Mohammad Lashkar Boloki

    2011-07-01

    Full Text Available This study was carried out to evaluate the effect of the product of commercial live bakers’ yeast ( Saccharomyces cerevisiae so called Amax on the growth and survival of Persian sturgeon( Acipenser persicus larvae via enrichment of Daphnia magna . The blends of Amax were used in three concentrations of 50, 100, 150 mg L-1 with Daphnia in suspension of broth. Every day Daphnia by one of concentrations was bioencapsulated for 10 hours and Persian sturgeon larvae were fed on it. The Acipenser persicus larvae were fed from Daphnia on the base of the 50 percent of their body weight five times a day. The control group was fed on not enriched Daphnia. The gained body weight in experimental treatments of sturgeon larvae had significant difference compared to control treatment (p0.05. The Amax had significant positive effects on survival rate in comparison with control treatment (p<0.05. The experiments indicated that the product of Saccharomyces cerevisiae has a high ability to increase the growth parameters and feeding efficiency in cultivation system of sturgeon fish.

  11. Laboratory evaluation of the toxicity of Perfluorooctane Sulfonate (PFOS) on Selenastrum capricornutum, Chlorella vulgaris, Lemna gibba, Daphnia magna, and Daphnia pulicaria.

    Science.gov (United States)

    Boudreau, T M; Sibley, P K; Mabury, S A; Muir, D G C; Solomon, K R

    2003-04-01

    Perfluorooctane sulfonate (PFOS) is an anthropogenic compound found in trace amounts in many environmental compartments far from areas of production. This, along with the highly persistent nature of PFOS, presents a concern for possible effects in aquatic ecosystems. The objective of this study was to determine the toxicity of PFOS in representative freshwater organisms. Toxicity testing using standard laboratory protocols was performed on the green algae Selenastrum capricornutum and Chlorella vulgaris, the floating macrophyte Lemna gibba, and the invertebrates Daphnia magna and Daphnia pulicaria. No observable effect concentration (NOEC) values were generated from the most sensitive endpoints for all organisms. Autotroph inhibition of growth NOEC values were 5.3, 8.2, and 6.6 mg/L for S. capricornutum, C. vulgaris, and L. gibba, respectively. The 48-h immobility NOEC values for D. magna and D. pulicaria were 0.8 and 13.6 mg/L, respectively. In comparison to immobility, the 21-day lethality NOEC for D. magna was 5.3 mg/L. Based on effect (immobility) values, the most sensitive of all test organisms was D. magna. The most sensitive organism based on 50% inhibition of growth (IC(50)) was L. gibba, with an IC(50) value of 31.1 mg/L determined from wet weight. This is 4.3 times less than the LC(50) for D. pulicaria, which was 134 mg/L. Significant adverse effects (p 134 mg/L. The results indicate that under laboratory conditions PFOS is acutely toxic to freshwater organisms at concentrations at or near 100 mg/L. Based on known environmental concentrations of PFOS, which occur in the low ng/L to low microg/L range, there is no apparent risk to freshwater systems. However, further work is required to investigate long-term effects in these and other freshwater organisms.

  12. Trophic transfer of gold nanoparticles from Euglena gracilis or Chlamydomonas reinhardtii to Daphnia magna.

    Science.gov (United States)

    Lee, Woo-Mi; Yoon, Sung-Ji; Shin, Yu-Jin; An, Youn-Joo

    2015-06-01

    Understanding the trophic transfer of nanoparticles (NPs) is important because NPs are small enough to easily penetrate into organisms. In this study, we evaluated the trophic transfer of gold NPs (AuNPs) within the aquatic food chain. We observed AuNPs transfer from 2 species of primary producers (Chlamydomonas reinhardtii or Euglena gracilis) to the primary consumer (Daphnia magna). Also, bioaccumulation of AuNPs in E. gracilis was higher than that in C. reinhardtii. The reasons for the difference in Au accumulation may be the physical structure of these organisms, and the surface area that is available for interaction with NPs. C. reinhardtii has a cell wall that may act as a barrier to the penetration of NPs. The size of E. gracilis is larger than that of C. reinhardtii. This study demonstrates the trophic transfer of AuNPs from a general producer to a consumer in an aquatic environment.

  13. Toxicity of inorganic and organic selenium to Daphnia magna (cladocera) and Chironomus riparius (diptera)

    Science.gov (United States)

    Ingersoll, Christopher G.; Dwyer, F.J.; May, T.W.

    1990-01-01

    Elevated concentrations of selenium (Se) have been previously measured in biota sampled from the Kesterson National Wildlife Refuge (KNWR) in the San Joaquin Valley of central California. We conducted acute and chronic toxicity tests with the cladoceran Daphnia magna and the midge Chironomus riparius to determine the toxicity or bioaccumulation of waterborne Se in a reconstituted water similar to the San Joaquin River. Daphnids were more acutely sensitive than midges to the toxic effects of inorganic Se. An organic form of Se (seleno-[L]-methionine) was extremely toxic to daphnids, but was relatively nontoxic to midges. In long-term exposure to a 6:1 mixture of selenate to selenite (a mixture representative of KNWR), the emergence time of adult midges was delayed at Se concentrations ≥ 837 μg/L. Daphnid reproduction and intrinsic rate of natural increase (r) were reduced at Se concentrations ≥ 348 μg/L and growth of adults was reduced at ≥ 156 μg/L. Whole body Mg, K and Na concentrations in daphnids were not affected by chronic Se exposure; however, whole body Ca concentration increased at intermediate Se exposure concentrations. In addition, whole body Cl concentration was reduced at 711 μg Se/L. Daphnids accumulated potentially toxic concentrations of Se from water that may adversely affect fish or waterfowl through the food chain.

  14. Neuroanatomy of the optic ganglia and central brain of the water flea Daphnia magna (Crustacea, Cladocera).

    Science.gov (United States)

    Kress, Timm; Harzsch, Steffen; Dircksen, Heinrich

    2016-03-01

    We reveal the neuroanatomy of the optic ganglia and central brain in the water flea Daphnia magna by use of classical neuroanatomical techniques such as semi-thin sectioning and neuronal backfilling, as well as immunohistochemical markers for synapsins, various neuropeptides and the neurotransmitter histamine. We provide structural details of distinct neuropiles, tracts and commissures, many of which were previously undescribed. We analyse morphological details of most neuron types, which allow for unravelling the connectivities between various substructural parts of the optic ganglia and the central brain and of ascending and descending connections with the ventral nerve cord. We identify 5 allatostatin-A-like, 13 FMRFamide-like and 5 tachykinin-like neuropeptidergic neuron types and 6 histamine-immunoreactive neuron types. In addition, novel aspects of several known pigment-dispersing hormone-immunoreactive neurons are re-examined. We analyse primary and putative secondary olfactory pathways and neuronal elements of the water flea central complex, which displays both insect- and decapod crustacean-like features, such as the protocerebral bridge, central body and lateral accessory lobes. Phylogenetic aspects based upon structural comparisons are discussed as well as functional implications envisaging more specific future analyses of ecotoxicological and endocrine disrupting environmental chemicals.

  15. Effect of salinity on the swimming velocity of the water flea Daphnia magna.

    Science.gov (United States)

    Baillieul, M; De Wachter, B; Blust, R

    1998-01-01

    The swimming velocity of the water flea Daphnia magna is dependent on its body size. Therefore, environmental factors that influence growth also influence swimming velocity. This study examined whether exposure to increased salinity reduces swimming velocity only through its effect on body size or whether it also reduces size-specific swimming velocity. Initially, size-specific swimming velocity decreased in a salinity-dependent way. Thereafter, swimming velocities gradually returned to their expected values in all treatments. This acclimation coincided with considerable mortality in the highest-salinity treatment, indicating that daphnids in this treatment either acclimated or died. The initial decrease in size-specific swimming velocity could not be explained by decreased uptake of food. Thus, the results indicate that salinity temporarily impaired physiology. The experiment illustrates how size effects can be accounted for in swimming-velocity analysis and how size-specific swimming-velocity analysis can be used as a non-invasive method to detect stress-induced deviations from normal physiology.

  16. Effects of enrofloxacin, ciprofloxacin, and trimethoprim on two generations of Daphnia magna.

    Science.gov (United States)

    Dalla Bona, Mirco; Zounková, Radka; Merlanti, Roberta; Blaha, Ludek; De Liguoro, Marco

    2015-03-01

    Multigenerational tests on Daphnia magna were performed exposing two subsequent generation to enrofloxacin (EFX) and its metabolite ciprofloxacin (CPX), and to trimethoprim (TMP). Mortality rate of 100% and 50% was detected in F0 at concentrations of ≥ 13 mgL(-1) (EFX) and 50 mgL(-1) (TMP), respectively. In F1 with respect to F0, both for growth and reproduction, a worsening trend of the response with EFX, a similar response with CPX and an attenuating trend with TMP was observed. Furthermore, the lowest EC20 for reproduction inhibition (1.3 mgL(-1)) was calculated for F1 exposed to EFX. However, other experimentations, longer and more complex, are necessary in order to confirm that EFX is more hazardous to daphnids than CPX and TMP. EC50 measured for the three assayed antibacterials were in the 6.5-37 mgL(-1) range therefore environmental unrealistic, except in case of exceptional contaminations that may occur in relation to poorly controlled wastewaters from pharmaceutical factories or excessive use of prophylactic treatments in aquaculture. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Citrate coated silver nanoparticles change heavy metal toxicities and bioaccumulation of Daphnia magna.

    Science.gov (United States)

    Kim, Injeong; Lee, Byung-Tae; Kim, Hyun-A; Kim, Kyoung-Woong; Kim, Sang Don; Hwang, Yu-Sik

    2016-01-01

    Citrate-coated AgNPs (c-AgNPs) have negatively charged surfaces and their surface interactions with heavy metals can affect metal toxicity in aquatic environments. This study used Daphnia magna to compare the acute toxicities and bioaccumulation of As(V), Cd, and Cu when they interact with c-AgNPs. The 24-h acute toxicities of As(V) and Cu were not affected by the addition of c-AgNPs, while bioaccumulation significantly decreased in the presence of c-AgNPs. In contrast, both the 24-h acute toxicity and bioaccumulation of Cd increased in the presence of c-AgNPs. These toxicity and bioaccumulation trends can be attributed to the interactions between the AgNP surface and the heavy metals. As(V) and c-AgNPs compete by negative charge, decreasing As(V) toxicity. Copper adheres readily to c-AgNP citrate, decreasing Cu bioavailability, and thus reducing Cu toxicity and bioaccumulation. Citrate complexes with divalent cations such as Ca and Mg reduce the competition between divalent cations and Cd on biotic ligand, increasing toxicity and bioaccumulation of Cd. This study shows that surface properties determine the effect of c-AgNPs on heavy metal toxicities and bioaccumulations; hence, further studies on the effect of nanoparticle by it surface properties are warranted.

  18. Toxicity of trace element and salinity mixtures to striped bass (Morone saxatilis) and Daphnia magna

    Science.gov (United States)

    Dwyer, F.J.; Burch, S.A.; Ingersoll, C.G.; Hunn, J.B.

    1992-01-01

    Acute toxicity tests with reconstituted water were conducted to investigate the relationship between water hardness, salinity, and a mixture of trace elements found in irrigation drain waters entering Stillwater Wildlife Management Area (SWMA), near Fallon, Nevada. The SWMA has been the site of many fish kills in recent years, and previous toxicity studies indicated that one drain water, Pintail Bay, was acutely toxic to organisms acclimated or cultured in fresh water or salt water. This toxicity could reflect both the ionic composition of this saline water and the presence of trace elements. The lowest water salinity tested with Daphnia magna was near the upper salinity tolerance of these organisms; therefore, we were unable to differentiate between the toxic effects of ion composition and those of trace elements. In toxicity tests conducted with striped bass (Morone saxatilis), we found that the extent to which salinity was lethal to striped bass depended on the ion composition of that salinity. Survival of striped bass increased as hardness increased. In addition, a trace element mixture was toxic to striped bass, even though the concentrations of individual elements were below expected acutely lethal concentrations. Although salinity is an important water quality characteristic, the ionic composition of the water must be considered when one assesses the hazard of irrigation drain waters to aquatic organisms.

  19. Acute toxicity of several esential oils on Daphnia magna (Straus, 1816.

    Directory of Open Access Journals (Sweden)

    Özlem Çakal Arslan

    2015-12-01

    Full Text Available Bu çalışmada, beslenme, tıbbi tedavi ve kozmetik endüstrisinde kullanımı söz konusu olan 6 çeşit bitkisel yağın Daphnia magna akut hareketsizlik testi ile etkili konsantrasyoları (EC50 belirlenmiştir. Toksisite testlerinde Biberiye, Okaliptüs, Üzüm Çekirdeği, Kekik, Çay Ağacı, Buğday özü yağları test maddesi olarak kullanılmıştır. Tüm yağların etki konsantrasyonları karşılaştırıldığında (EC50 Kekik yağının diğerlerine göre daha toksik olduğu belirlenmiştir

  20. Hazard assessment for a pharmaceutical mixture detected in the upper Tennessee River using Daphnia magna

    Directory of Open Access Journals (Sweden)

    D. Wolfe

    2015-01-01

    Full Text Available Widespread use of pharmaceuticals has resulted in mixture concentrations ranging from mg/L in effluent to µg/L concentrations in surface water. In a 2008 study, 13 pharmaceuticals, ranging in amounts from 0.0028 to 0.1757 µg/l, were identified in the Tennessee River, USA and its tributaries. In order to address the need for risk assessment of environmentally relevant pharmaceutical mixtures, Daphnia magna 21-d life cycle tests were performed on a mixture of 11 of the 13 pharmaceuticals as well as on the individual components of the mixture. Mixture exposures were based on the same initial ratios of individual compounds, up to 1000x the initial mixture concentrations.  The endpoints of mortality, time to first brood, size, and fecundity were the assessed.  The LOEC of the 11- pharmaceutical mixture was determined to be 100x greater than the measured mixture concentration detected in the Tennessee River, with the NOEC being 75x that of the measured mixture.  Single concentrations of pharmaceuticals within the mixture up to the 100x LOEC were not statistically different from control for any of the assessed endpoints.  Thus, no single pharmaceutical was deemed predominately responsible for the mixture toxicity at the concentrations tested. While mixtures of pharmaceuticals are common in many systems, based on the findings of the present study, they may not pose a significant acute or chronic hazard to aquatic invertebrates at current concentrations.

  1. Effect of pH on the toxicity and bioconcentration of sulfadiazine on Daphnia magna

    DEFF Research Database (Denmark)

    Anskjær, Gitte Gotholdt; Rendal, Cecilie; Kusk, Kresten Ole

    2013-01-01

    The antimicrobial sulfonamide sulfadiazine has in the last decades been detected in environmental water bodies, both surface and ground water. Since pH in the environment may vary considerably, this study examined the toxicity of the amphoter sulfadiazine towards Daphnia magna at pH levels of 6.......0, 7.5 and 8.5, thus taking the impact of speciation into consideration, contrary to earlier eco-toxicity studies conducted at standard conditions. Toxicity tests were performed using the standard ISO 6341 test procedure modified to accommodate the three pH levels and the toxicity was expressed as EC50....... After 48h the EC50 was determined to be 27.2, 188 and 310mgL−1 at pH 6.0, 7.5 and 8.5, respectively, thus demonstrating a significant effect of pH on the toxicity of sulfadiazine. Furthermore, the bioconcentration factor (dry weight) was determined to be 50 and 36 at pH 6.0 and 8.5, respectively...

  2. Evolutionary variation in neural gene expression in the developing sense organs of the crustacean Daphnia magna.

    Science.gov (United States)

    Klann, Marleen; Stollewerk, Angelika

    2017-02-24

    Arthropods have numerous sense organs, which are adapted to their habitat. While some sense organs are similar in structure and function in all arthropod groups, structural differences in functionally related sense organs have been described, as well as the absence of particular sense organ subtypes in individual arthropod groups. Here we address the question of how the diverse structures of arthropod sense organs have evolved by analysing the underlying molecular developmental processes in a crustacean, an arthropod group that has been neglected so far. We have investigated the development of four types of chemo- and mechanosensory sense organs in the branchiopod Daphnia magna (Cladocera) that either cannot be found in arthropods other than crustaceans or represent adaptations to an aquatic environment. The formation of the sensory organ precursors shows greater similarity to the arthropod taxa Chelicerata and Myriapoda than to the more closely related insects. All analysed sense organ types co-express the proneural genes ASH and atonal regardless of their structure and function. In contrast, in Drosophila melanogaster, ASH and atonal expression does not overlap and the genes confer different sense organ subtype identities. We performed experimental co-expression studies in D. melanogaster and found that the combinatorial expression of ato and ASH can change the external structure of sense organs. Our results indicate a central role for ASH and Atonal family members in the emergence of structural variations in arthropod sense organs.

  3. Ectoine alleviates behavioural, physiological and biochemical changes in Daphnia magna subjected to formaldehyde.

    Science.gov (United States)

    Bownik, Adam; Stępniewska, Zofia

    2015-10-01

    Ectoine (ECT) is produced by halophilic microorganisms in response to various stressful factors. Its protective properties in bacteria and some populations of isolated cells are known; however, no data are available on its protective influence on aquatic invertebrates subjected to a common pollutant, formaldehyde (FA). The purpose of this study was to determine the effects of FA alone (at 20 and 60 mg/L) and in the combination with various concentrations of ECT (5, 10 and 25 mg/L) at various times of exposure on behavioural, physiological and biochemical parameters of Daphnia magna. Specifically, mortality, heart rate, thoracic limb movement, reduced glutathione (GSH)/oxidised glutathione (GSSG) ratio, catalase (CAT) activity and nitric oxide (NOx) levels were determined. The results showed that both concentrations of FA when administered alone induced significant alterations of the determined parameters. On the other hand, animals treated with the combinations of FA + ECT showed decreased mortalities, attenuated inhibition of heart rates and thoracic limb activities, less decreased GSH/GSSG ratios, lower stimulation of CAT activities and NOx levels when compared to the crustaceans subjected to FA alone. The most distinct attenuation of toxic effects was observed in the combinations in which the highest concentrations of ECT were used. The results suggest that oxidative stress induced by FA in daphnids is likely to be alleviated by the antioxidative action of ECT.

  4. Development and evaluation of new behavioral indexes for a biological early warning system using Daphnia magna

    Directory of Open Access Journals (Sweden)

    T. Y. Jeong

    2013-03-01

    Full Text Available New behavioral indexes including combined index (CI, distribution index (DI, toxic index (TI, and altitude index (AI for a biological early warning system (BEWS were developed and evaluated using Daphnia magna in this study. The sensitivity and stability of each index were compared to evaluate the performance of the indexes through a real-time exposure test with a synthetic copper solution. The applicability of the CI to the field sample was evaluated through an effluent exposure test. The proportional relationship between toxicity level and magnitude of response was much lower in the effluent due to the complexity of water than in the copper solution. The results showed that the CI was most sensitive among the three indexes, while the DI was confirmed as the most useful index among the individual indexes. The combined index (CI shows not only sensitivity but also stability in normal conditions below the statistically significant threshold (p p > 0.01. The CI improved performance of the BEWS in terms of sensitivity and stability, and it was confirmed as the higher correlation coefficient between the magnitude of the index and the toxicity level of the water sample.

  5. Phenotypic integration plasticity in Daphnia magna: an integral facet of G × E interactions.

    Science.gov (United States)

    Plaistow, S J; Collin, H

    2014-09-01

    Phenotypic integration can be defined as the network of multivariate relationships among behavioural, physiological and morphological traits that describe the organism. Phenotypic integration plasticity refers to the change in patterns of phenotypic integration across environments or ontogeny. Because studies of phenotypic plasticity have predominantly focussed on single traits, a G × E interaction is typically perceived as differences in the magnitude of trait expression across two or more environments. However, many plastic responses involve coordinated responses in multiple traits, raising the possibility that relative differences in trait expression in different environments are an important, but often overlooked, source of G × E interaction. Here, we use phenotypic change vectors to statistically compare the multivariate life-history plasticity of six Daphnia magna clones collected from four disparate European populations. Differences in the magnitude of plastic responses were statistically distinguishable for two of the six clones studied. However, differences in phenotypic integration plasticity were statistically distinguishable for all six of the clones studied, suggesting that phenotypic integration plasticity is an important component of G × E interactions that may be missed unless appropriate multivariate analyses are used.

  6. Daphnia magna's sense of competition: intra-specific interactions (ISI) alter life history strategies and increase metals toxicity.

    Science.gov (United States)

    Gust, Kurt A; Kennedy, Alan J; Melby, Nicolas L; Wilbanks, Mitchell S; Laird, Jennifer; Meeks, Barbara; Muller, Erik B; Nisbet, Roger M; Perkins, Edward J

    2016-08-01

    This work investigates whether the scale-up to multi-animal exposures that is commonly applied in genomics studies provides equivalent toxicity outcomes to single-animal experiments of standard Daphnia magna toxicity assays. Specifically, we tested the null hypothesis that intraspecific interactions (ISI) among D. magna have neither effect on the life history strategies of this species, nor impact toxicological outcomes in exposure experiments with Cu and Pb. The results show that ISI significantly increased mortality of D. magna in both Cu and Pb exposure experiments, decreasing 14 day LC50 s and 95 % confidence intervals from 14.5 (10.9-148.3) to 8.4 (8.2-8.7) µg Cu/L and from 232 (156-4810) to 68 (63-73) µg Pb/L. Additionally, ISI potentiated Pb impacts on reproduction eliciting a nearly 10-fold decrease in the no-observed effect concentration (from 236 to 25 µg/L). As an indication of environmental relevance, the effects of ISI on both mortality and reproduction in Pb exposures were sustained at both high and low food rations. Furthermore, even with a single pair of Daphnia, ISI significantly increased (p history strategy. Given these results we reject the null hypothesis and conclude that results from scale-up assays cannot be directly applied to observations from single-animal assessments in D. magna. We postulate that D. magna senses chemical signatures of conspecifics which elicits changes in life history strategies that ultimately increase susceptibility to metal toxicity.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  9. Effects of Ammonia and Density on Filtering of Commensal and Pathogenic Escherichia coli by the Cladoceran Daphnia magna.

    Science.gov (United States)

    Nørgaard, Louise Solveig; Roslev, Peter

    2016-12-01

    Grazing by cladocerans can reduce the survival of enteric bacteria associated with fecal pollution. This study examined the potential of Daphnia magna to filter commensal and pathogenic Escherichia coli of human origin. Grazing on commensal and pathogenic bacteria was comparable, but slightly greater at 20 compared to 15 and 25°C. Filtering activity was strongly dependent on D. magna and E. coli densities at environmentally relevant bacterial concentrations. Maximum feeding rates were >10(7) cells h(-1) daphnid(-1), clearance rates were 1-6 mL h(-1) daphnid(-1), and filtering was independent of bacterial cell sizes between 0.7 and 1.8 µm. Filtering and ingestion of E. coli by D. magna was susceptible to acute inhibition by unionized ammonia with a 24 h EC50 of 0.18 mg L(-1) NH3-N, and a LOEC of 0.09 mg L(-1) NH3-N. The study indicated that biological and chemical constraints should be considered when applying Daphnia for attenuation of fecal pollution.

  10. Oxidative stress responses of Daphnia magna exposed to effluents spiked with emerging contaminants under ozonation and advanced oxidation processes.

    Science.gov (United States)

    Oropesa, Ana Lourdes; Novais, Sara C; Lemos, Marco F L; Espejo, Azahara; Gravato, Carlos; Beltrán, Fernando

    2017-01-01

    Integration of conventional wastewater treatments with advanced oxidation processes (AOPs) has become of great interest to remove pharmaceuticals and their metabolites from wastewater. However, application of these technologies generates reactive oxygen species (ROS) that may reach superficial waters through effluents from sewage treatment plants. The main objective of the present study was to elucidate if ROS present in real effluents after biological and then chemical (single ozonation, solar photolytic ozonation, solar photocatalytic ozonation (TiO2, Fe3O4) and solar photocatalytic oxidation (TiO2)) treatments induce oxidative stress in Daphnia magna. For this, the activity of two antioxidant enzymes (superoxide dismutase and catalase) and the level of lipid peroxidation were determined in Daphnia. The results of oxidative stress biomarkers studied suggest that D. magna is able to cope with the superoxide ion radical (O2·(-)) present in the treated effluent due to single ozonation by mainly inducing the antioxidant activity superoxide dismutase, thus preventing lipid peroxidation. Lethal effects (measured in terms of immobility) were not observed in these organisms after exposure to any solution. Therefore, in order to probe the ecological efficiency of urban wastewater treatments, studies on lethal and sublethal effects in D. magna would be advisable.

  11. Effects of aged TiO2 nanomaterial from sunscreen on Daphnia magna exposed by dietary route.

    Science.gov (United States)

    Fouqueray, Manuela; Dufils, Benjamin; Vollat, Bernard; Chaurand, Perrine; Botta, Celine; Abacci, Khedidja; Labille, Jerome; Rose, Jerome; Garric, Jeanne

    2012-04-01

    The toxicity of dietary exposure to artificially aged TiO(2) nanomaterial (T-Lite™) used in sunscreen cream was studied on D. magna. Pseudokirchneriella subcapitata cultures were contaminated with TiO(2)-residues, obtained by artificial aging. Significant association of TiO(2)-residues on algae was detected by X-ray fluorescence spectromicroscopy. A D. magna dietary chronic exposure of these contaminated algae with TiO(2)-residues was performed. X-ray chemical imaging revealed that Ti was localized only in the digestive tract of the daphnia. Chronic exposure of daphnia to by-product of aged TiO(2) nanoparticles brought by food induced low mortality but decreased growth and reproduction which can be partly related to the modification of the digestive physiology of daphnia. This study demonstrated that the assessment of the ecotoxicological impact of nanomaterials in aquatic environment should take into account the aging of these materials which can further influence their bioavailability for aquatic organisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. The influence of natural organic matter and aging on suspension stability in guideline toxicity testing of silver, zinc oxide, and titanium dioxide nanoparticles with Daphnia magna

    DEFF Research Database (Denmark)

    Cupi, Denisa; Hartmann, Nanna Isabella Bloch; Baun, Anders

    2015-01-01

    The present study investigated changes in suspension stability and ecotoxicity of engineered nanoparticles (ENPs) by addition of Suwannee River natural organic matter and aging of stock and test suspensions prior to testing. Acute toxicity tests of silver (Ag), zinc oxide (ZnO), and titanium...... dioxide (TiO2) ENPs with Daphnia magna were carried out following Organisation for Economic Co-operation and Development test guidelines. Daphnia magna was found to be very sensitive to Ag ENPs (48-h 50% effective concentration 33μgL-1), and aging of the test suspensions in M7 medium (up to 48h) did...

  13. Bioavailability and toxicity of trace metals to the cladoceran Daphnia magna in relation to cadmium exposure history

    Science.gov (United States)

    Guan, Rui

    The cladoceran Daphnia magna is widely used in freshwater bioassessments and ecological risk assessments. This study designed a series of experiments employing radiotracer methodology to quantify the trace metals (mainly Cd and Zn) biokinetics in D. magna under different environmental and biological conditions and to investigate the influences of different Cd exposure histories on the bioavailability and toxicity of trace metals to D. magna. A bioenergetic-based kinetic model was finally applied in predicting the Cd accumulation dynamics in D. magna and the model validity under non-steady state was assessed. Cd assimilation was found in this study to be influenced by the food characteristics (e.g., metal concentration in food particles), the metal exposure history of the animals, and the genetic characteristics. Some of these influences could be interpreted by the capacity and/or competition of those metal binding sites within the digestive tract and/or the detoxifying proteins metallothionein (MT). My study demonstrated a significant induction of MT in response to Cd exposure and it was the dominant fraction in sequestering the internal nonessential trace metals in D. magna. The ratio of Cd body burden to MT might better predict the Cd toxicity on the digestion systems of D. magna than the Cd tissue burden alone within one-generational exposure to Cd. It was found that metal elimination (rate constant and contribution of different release routes) was independent of the food concentration and the dietary metal concentration, implying that the elimination may not be metabolically controlled. The incorporation of the bioenergetic-based kinetic model, especially under non-steady state, is invaluable in helping to understand the fate of trace metals in aquatic systems and potential environmental risks. The dependence of biokinetic parameters on environmental factors rather than on genotypes implies a great potential of using biokinetics in inter-laboratory comparisons.

  14. Enhanced Oxidative Stress and Physiological Damage in Daphnia magna by Copper in the Presence of Nano-TiO2

    Directory of Open Access Journals (Sweden)

    W. H. Fan

    2012-01-01

    Full Text Available This study examines the potential hazard of an individual nanomaterial on the Cu biotoxicity to aquatic organisms. Daphnia magna in the absence or presence of nano-TiO2 was exposed to Cu. Maintaining nano-TiO2 at a safe concentration cannot eliminate its potential hazard. The biomarkers superoxide dismutase, catalase, and Na+/K+-ATPase in D. magna were measured. Cu in the presence of nano-TiO2 induced higher levels of oxidative stress and physiological damage because of the sorption of Cu. Nano-TiO2 also caused Na+/K+-ATPase inhibition possibly by impeding the Na+/K+ transfer channel. The correlations among the biomarkers, mortality, and accumulation further showed that the overloading reactive oxygen species generation caused by nano-TiO2 contributed to deeper oxidative stress and physiological regulation, thereby causing greater toxic injury.

  15. [Bioremediation efficiency of applying Daphnia magna and submerged plants: a case study in Dishui Lake of Shanghai, China].

    Science.gov (United States)

    Huo, Yuan-Zi; He, Wen-Hui; Luo, Kun; Wang, Yang-Yang; Zhang, Yin-Jiang; Tian, Qian-Tao; He, Pei-Min

    2010-02-01

    From April 2007 to January 2008, a bioremediation experiment was conducted in a diversion channel of D-port pilot area of Dishui Lake (the channel length is 950 m, and its water volume is 10000 m3). Daphnia magna was first introduced to filter the high biomass of phytoplankton and other particulate organic matter, and then, five submerged plant species Elodea canadensis, Vallisneria spiralis, Hydrilla verticillata, Potamogeton lucens, and Potamogeton crispus were transplanted. Water samples were collected monthly to monitor the water quality and to investigate the bioremediation efficiency. Ten months monitoring data showed that in the remediation area, the water body's total nitrogen (TN), ammonium nitrogen (NH4(+)-N), nitrate nitrogen (NO3(-)-N), nitrite nitrogen (NO2(-)-N), total phosphorus (TP), and reactive phosphate (PO4(3-)-P) concentrations and chemical oxygen demand (COD) were significantly lower (P study demonstrated the effectiveness of introducing D. magna and transplanting submerged plants in improving the water quality of Dishui Lake.

  16. Metabolomics reveals energetic impairments in Daphnia magna exposed to diazinon, malathion and bisphenol-A.

    Science.gov (United States)

    Nagato, Edward G; Simpson, André J; Simpson, Myrna J

    2016-01-01

    (1)H nuclear magnetic resonance (NMR)-based metabolomics was used to study the response of Daphnia magna to increasing sub-lethal concentrations of either an organophosphate (diazinon or malathion) or bisphenol-A (BPA). Principal component analysis (PCA) of (1)H NMR spectra were used to screen metabolome changes after 48h of contaminant exposure. The PCA scores plots showed that diazinon exposures resulted in aberrant metabolomic profiles at all exposure concentrations tested (0.009-0.135 μg/L), while for malathion the second lowest (0.08μg/L) and two highest exposure concentrations (0.32μg/L and 0.47μg/L) caused significant shifts from the control. Individual metabolite changes for both organophosphates indicated that the response to increasing exposure was non-linear and described perturbations in the metabolome that were characteristic of the severity of exposure. For example, intermediate concentrations of diazinon (0.045μg/L and 0.09μg/L) and malathion (0.08μg/L) elicited a decrease in amino acids such as leucine, valine, arginine, glycine, lysine, glutamate, glutamine, phenylalanine and tyrosine, with concurrent increases in glucose and lactate, suggesting a mobilization of energy resources to combat stress. At the highest exposure concentrations for both organophosphates there was evidence of a cessation in metabolic activity, where the same amino acids increased and glucose and lactate decreased, suggesting a slowdown in protein synthesis and depletion of energy stocks. This demonstrated a similar response in the metabolome between two organophosphates but also that intermediate and severe stress levels could be differentiated by changes in the metabolome. For BPA exposures, the PCA scores plot showed a significant change in metabolome at 0.1mg/L, 1.4mg/L and 2.1mg/L of exposure. Individual metabolite changes from 0.7 to 2.1mg/L of BPA exposure showed increases in amino acids such as alanine, valine, isoleucine, leucine, arginine, phenylalanine and

  17. Acute and chronic toxicity of selected disinfection byproducts to Daphnia magna, Cyprinodon variegatus, and Isochrysis galbana.

    Science.gov (United States)

    Fisher, Daniel; Yonkos, Lance; Ziegler, Gregory; Friedel, Elizabeth; Burton, Dennis

    2014-05-15

    Ballast water treatment has become a major issue in the last decade due to the problem of invasive species transported and released by the uptake and discharge of ballast water for shipping operations. One of the important issues considering ballast water treatment is to determine whether treated ballast water, once discharged, is safe to the aquatic environment. The International Maritime Organization (IMO) Marine Environmental Protection Committee (MEPC) has determined that prior to approval of a ballast water management system, aquatic toxicity data must be available for both the active substance and relevant byproducts. Many proposed ballast water treatment systems use chlorine as the active ingredient. Although there are sufficient toxicity data concerning active substances such as chlorine, there are limited toxicity data concerning disinfection (halogenated) byproducts including dibromochloromethane, four haloacetic acids and sodium bromate. Acute and chronic toxicity were determined for these disinfection byproducts (DBPs). Acute toxicity values ranged from 96-h LC50s of 46.8 mg/l for Daphnia magna for both dibromochloromethane and sodium bromate to a 96-h LC50 of 376.4 mg/l for Cyprinodon variegatus for tribromoacetic acid. Acute Isochrysis galbana population growth effect values ranged from a 72-h EC10 of 39.9 mg/l for dichloroacetic acid to a 72-h EC50 of 15,954 mg/l for sodium bromate. Chronic toxicity mortality/reproduction effects values for D. magna ranged from a 21-d IC25 of 160.9 mg/l for tribromoacetic acid to a 21-d LOEC of 493.0 mg/l for trichloroacetic acid. Chronic toxicity mortality/growth values for C. variegatus ranged from a 32-d IC25 of 246.8 mg/l for trichloroacetic acid to a 32-d LOEC of 908.1 mg/l for tribromoacetic acid. I. galbana 96-h chronic population growth effects values ranged from an EC10 of 38.5 mg/l for trichloroacetic acid to an LOEC of 500.0 mg/l for tribromoacetic acid. Acute to chronic ratios for all of these

  18. Population growth of the Cladoceran, Daphnia magna: a quantitative analysis of the effects of different algal food.

    Directory of Open Access Journals (Sweden)

    Jong-Yun Choi

    Full Text Available In this study, we examined the effects of two phytoplankton species, Chlorella vulgaris and Stephanodiscus hantzschii, on growth of the zooplankton Daphnia magna. Our experimental approach utilized stable isotopes to determine the contribution of food algae to offspring characteristics and to the size of adult D. magna individuals. When equal amounts of food algae were provided (in terms of carbon content, the size of individuals, adult zooplankton, and their offspring increased significantly following the provision of S. hantzschii, but not after the provision of C. vulgaris or of a combination of the two species. Offspring size was unaffected when C. vulgaris or a mixture of the two algal species was delivered, whereas providing only S. hantzschii increased the production of larger-sized offspring. Stable isotope analysis revealed significant assimilation of diatom-derived materials that was important for the growth of D. magna populations. Our results confirm the applicability of stable isotope approaches for clarifying the contribution of different food algae and elucidate the importance of food quality for growth of D. magna individuals and populations. Furthermore, we expect that stable isotope analysis will help to further precisely examine the contribution of prey to predators or grazers in controlled experiments.

  19. Toxicity assessment of metabolites of fungal biocontrol agents using two different (Artemia salina and Daphnia magna) invertebrate bioassays.

    Science.gov (United States)

    Favilla, M; Macchia, L; Gallo, A; Altomare, C

    2006-11-01

    Fungal biocontrol agents (BCAs) have been marketed for control of crop pests, weeds, and diseases. However, BCAs may produce toxic metabolites, whose presence in the formulated products, in the crops and in the environment should be considered along with the associated risk. Two invertebrate models, viz. Artemia salina and Daphnia magna were used to assess the acute toxicity of seven BCA metabolites, characterized by different chemical nature and mode of action, namely alamethicin (ALA), paracelsin (PCS), antiamoebin (AAM), gliotoxin (GTX), destruxin A (DA), oosporein (OOS), and elsinochrome A (EA). The two invertebrates were very sensitive to all the metabolites examined, except OOS. The LC50s after 24 and 36 h exposures showed the following toxicity ranks: A. salina, DA > ALA > EA > GTX > AAM > PCS (LC50s ranging from 9.78 to 40.84 microg/ml at 24 h and from 2.92 to 18.56 microg/ml at 36 h); D. magna, DA > GTX = EA > ALA > PCS > AAM (LC50s ranging from 0.20 to 24.41 microg/ml at 24h and from 0.16 to 11.98 microg/ml at 36 h). LC50 of OOS to D. magna increased dramatically in 36 h exposure, compared to 24 h exposures (5.84 and 68.40 microg/ml, respectively). A. salina and D. magna proved to be suitable models for rapid and inexpensive screening of toxicity of BCAs at an early stage of product development.

  20. Bioaccumulation and in-vivo dissolution of CdSe/ZnS with three different surface coatings by Daphnia magna.

    Science.gov (United States)

    Lee, Byung-Tae; Kim, Hyun-A; Williamson, Jacob L; Ranville, James F

    2016-01-01

    Daphnia magna were exposed to nano-sized CdSe/ZnS quantum dots (QDs) having three different surface coatings. QDs were investigated for their aqueous stability in the test media (hard reconstituted laboratory water) and for their uptake, elimination, and in-vivo dissolution. Positively charged QDs (QEI) and negatively charged QDs (QSH) were electrostatically stable, whereas neutrally charged QDs (QSA) showed aggregation and sedimentation over 48-h. After 24h of exposure to QDs (100μg/L as total Cd), the D. magna whole body Cd concentration significantly increased with no mortality for all QDs. Uptake patterns differed among the three coatings and Cd concentration reached 1460±50, 1014±99, and 584±81μg Cd/g dry wt for QEI, QSH, and QSA, respectively. Significant amounts of QEI and QSA (40% and 43%, respectively) remained in the D. magna after 24h of depuration, while 89% QSH were readily excreted within the initial 1h of the depuration stage. Soluble Cd was released from QDs during both the uptake and depuration. Release of Cd was higher in QEI and QSA than QSH, possibly resulting from the longer retention of QEI and QSA in the D. magna than QSH. These results imply that the surface charge of QDs plays a significant role in both the exposure to organisms and the in-vivo dissolution of nanoparticles.

  1. A comparative study of the acute toxicity of the herbicide atrazine to cladocerans Daphnia magna, Ceriodaphnia silvestrii and Macrothrix flabelligera

    Directory of Open Access Journals (Sweden)

    Raquel Aparecida Moreira

    2014-03-01

    Full Text Available AIM: In this study we compared the sensitivity of three species of Cladocera, Daphnia magna, Ceriodaphnia silvestrii and Macrothrix flabelligera, to the commercial product of the herbicide Atrazine, the Atrazine Atanor 50 SC® (500 g/L, widely used on crops in Brazil. METHODS: Acute toxicity tests were performed at the nominal atrazine concentrations 2.25, 4.5, 9.0, 18.0, 36 and 72 mg L-1, on C. silvestrii and M. flabelligera and at 2.25, 4.5, 9.0, 18.0, 36, 72 and 144 mg L-1 on D. magna. The range of concentrations tested was established in a series of preliminary tests. RESULTS: The toxicity tests showed that the two species naturally occurring in water bodies in Brazil were more susceptible than Daphnia magna. The effective concentrations of Atrazine Atanor 50 SC® (EC50- 48 h to the species M. flabelligera, C. silvestrii and D. magna were 12.37 ± 2.67 mg L-1, 14.30 ± 1.55 mg L-1 and 50.41 ± 2.64 mg L-1, respectively. Furthermore, when EC50 observed here for M. flabelligera and C. silvestrii were compared with published values of EC50 or LC50 (mg L-1 for various aquatic organisms exposed to atrazine, it was seen that these two cladocerans were the most sensitive to the herbicide. CONCLUSIONS: Considering these results and the broad distribution of C. silvestrii and M. flabelligera in tropical and subtropical regions, it is concluded that these native species would be valuable test organisms in ecotoxicological tests, for the monitoring of toxic substances in tropical freshwaters.

  2. Regulation and dysregulation of vitellogenin mRNA accumulation in daphnids (Daphnia magna)

    Energy Technology Data Exchange (ETDEWEB)

    Hannas, Bethany R.; Wang, Ying H.; Thomson, Susanne; Kwon, Gwijun; Li Hong [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633 (United States); LeBlanc, Gerald A., E-mail: Gerald_LeBlanc@ncsu.edu [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633 (United States)

    2011-01-25

    The induction of vitellogenin in oviparous vertebrates has become the gold standard biomarker of exposure to estrogenic chemicals in the environment. This biomarker of estrogen exposure also has been used in arthropods, however, little is known of the factors that regulate the expression of vitellogenin in these organisms. We investigated changes in accumulation of mRNA products of the vitellogenin gene Vtg2 in daphnids (Daphnia magna) exposed to a diverse array of chemicals. We further evaluated the involvement of hormonal factors in the regulation of vitellogenin expression that may be targets of xenobiotic chemicals. Expression of the Vtg2 gene was highly responsive to exposure to various chemicals with an expression range spanning approximately four orders of magnitude. Chemicals causing the greatest induction were piperonyl butoxide, chlordane, 4-nonylphenol, cadmium, and chloroform. Among these, only 4-nonylphenol is recognized to be estrogenic. Exposure to several chemicals also suppressed Vtg2 mRNA levels, as much as 100-fold. Suppressive chemicals included cyproterone acetate, acetone, triclosan, and atrazine. Exposure to the estrogens diethylstilbestrol and bisphenol A had little effect on vitellogenin mRNA levels further substantiating that these genes are not induced by estrogen exposure. Exposure to the potent ecdysteroids 20-hydroxyecdysone and ponasterone A revealed that Vtg2 was subject to strong suppressive control by these hormones. Vtg2 mRNA levels were not significantly affected from exposure to several juvenoid hormones. Results indicate that ecdysteroids are suppressors of vitellogenin gene expression and that vitellogenin mRNA levels can be elevated or suppressed in daphnids by xenobiotics that elicit antiecdysteroidal or ecdysteroidal activity, respectively. Importantly, daphnid Vtg2 is not elevated in response to estrogenic activity.

  3. Sodium uptake in different life stages of crustaceans: the water flea Daphnia magna Strauss.

    Science.gov (United States)

    Bianchini, Adalto; Wood, Chris M

    2008-02-01

    The concentration-dependent kinetics and main mechanisms of whole-body Na+ uptake were assessed in neonate and adult water flea Daphnia magna Strauss acclimated to moderately hard water (0.6 mmol l(-1) NaCl, 1.0 mmol l(-1) CaCO3 and 0.15 mmol l(-1) MgSO4.7H2O; pH 8.2). Whole-body Na+ uptake is independent of the presence of Cl(-) in the external medium and kinetic parameters are dependent on the life stage. Adults have a lower maximum capacity of Na+ transport on a mass-specific basis but a higher affinity for Na+ when compared to neonates. Based on pharmacological analyses, mechanisms involved in whole-body Na+ uptake differ according to the life stage considered. In neonates, a proton pump-coupled Na+ channel appears to play an important role in the whole-body Na+ uptake at the apical membrane. However, they do not appear to contribute to whole-body Na+ uptake in adults, where only the Na+ channel seems to be present, associated with the Na+/H+ exchanger. In both cases, carbonic anhydrase contributes by providing H+ for the transporters. At the basolateral membrane of the salt-transporting epithelia of neonates, Na+ is pumped from the cells to the extracellular fluid by a Na+, K+-ATPase and a Na+/Cl(-) exchanger whereas K+ and Cl(-) move through specific channels. In adults, a Na+/K+/2Cl(-) cotransporter replaces the Na+/Cl(-) exchanger. Differential sensitivity of neonates and adults to iono- and osmoregulatory toxicants, such as metals, are discussed with respect to differences in whole-body Na+ uptake kinetics, as well as in the mechanisms of Na+ transport involved in the whole-body Na+ uptake in the two life stages.

  4. Propulsion of the Water Flea, Daphnia magna: Experiments, Scaling, and Modelling

    Science.gov (United States)

    Skipper, A. N.; Murphy, D.; Webster, D. R.; Yen, J.

    2016-02-01

    The freshwater crustacean Daphnia magna is a widely studied zooplankton in relation to food webs, predator-prey interactions, and other biological/ecological considerations; however, their locomotion is poorly quantified and understood. These water fleas utilize a hop-and-sink mechanism that consists of making quick, impulsive jumps by beating their antennae to propel themselves forward ( 1 body length). The animals then sink for a period, during which they stretch out their antennae to increase drag and thereby reduce their sinking velocity. Time-resolved three-dimensional flow fields surrounding the animals were quantified with a unique infrared tomographic particle image velocity (tomo-PIV) system. Three-dimensional kinematics data were also extracted from the image sequences. In the current work, we compared body kinematics and flow disturbance among organisms of size in the range of 1.3 to 2.8 mm. The stroke cycle averaged 150 ms in duration, ranging from 100 to 180 ms; this period is generally evenly split between the power and recovery strokes. The range of peak hop velocity was 27.2 to 32.5 mm/s, and peak acceleration was in the range of 0.68 to 1.8 m/s2. The results showed a distinct relationship between peak hop speed (Vmax 14 BL/s) and body size; these data collapsed onto a single time-record curve during the power stroke when properly non-dimensionalized. The fluid flow induced by each antennae consisted of a viscous vortex ring that demonstrated a slow decay in the wake. The strength, size, and decay of the induced viscous vortex rings were compared as a function of organism size. Finally, the viscous vortex rings were analyzed in the context of a double Stokeslet model that consisted of two impulsively applied point forces separated by the animal width.

  5. Anticipatory maternal effects in two different clones of Daphnia magna in response to food shortage

    Directory of Open Access Journals (Sweden)

    Valeria ROSSI

    2011-08-01

    Full Text Available The effects of food shortage on growth, fecundity, male production and offspring size and starvation tolerance in two different clones of Daphnia magna (Clone L and Clone P were evaluated by disentangling the effects of resource depletion and crowding per se. Three experimental conditions were tested: high food - low daphnid density (the optimum, low food - low daphnid density and high food - high daphnid density. In the two first conditions, daphnids experienced the same population density but they had different food availability. In the two latter conditions, daphnids had the same per capita, low, food availability but they lived at different algae and daphnid densities. Moreover, the response of crowded females to recovery at high food availability and low population density was evaluated. Low food availability reduced growth and fecundity of both clones and increased male production only in the Clone L. Crowding per se did not affect growth but reduced fecundity. In both clones, low food availability due to low algae density enhanced investment in offspring size and resistance to starvation. In response to food shortage either due to low algae density and to crowding, Clone P increased the investment in offspring size and starvation tolerance but reduced fecundity to a lesser extent than Clone L and did not produce males. Clone L, in response to food shortage due to crowding at high algae density, increased development time, produced more males, as at low algae density, but halved fecundity producing offspring that were not starvationtolerant. These results might reflect differences in anticipatory maternal effects between clones and suggest that neonate quality varies according to either, the environment the mother experienced and the competitive environment the neonates will cope due to their mother life strategy.

  6. A Photoreceptor Contributes to the Natural Variation of Diapause Induction in Daphnia magna.

    Science.gov (United States)

    Roulin, Anne C; Bourgeois, Yann; Stiefel, Urs; Walser, Jean-Claude; Ebert, Dieter

    2016-12-01

    Diapause is an adaptation that allows organisms to survive harsh environmental conditions. In species occurring over broad habitat ranges, both the timing and the intensity of diapause induction can vary across populations, revealing patterns of local adaptation. Understanding the genetic architecture of this fitness-related trait would help clarify how populations adapt to their local environments. In the cyclical parthenogenetic crustacean Daphnia magna, diapause induction is a phenotypic plastic life history trait linked to sexual reproduction, as asexual females have the ability to switch to sexual reproduction and produce resting stages, their sole strategy for surviving habitat deterioration. We have previously shown that the induction of resting stage production correlates with changes in photoperiod that indicate the imminence of habitat deterioration and have identified a Quantitative Trait Locus (QTL) responsible for some of the variation in the induction of resting stages. Here, new data allows us to anchor the QTL to a large scaffold and then, using a combination of a new mapping panel, targeted association mapping and selection analysis in natural populations, to identify candidate genes within the QTL. Our results show that variation in a rhodopsin photoreceptor gene plays a significant role in the variation observed in resting stage induction. This finding provides a mechanistic explanation for the link between diapause and day-length perception that has been suggested in diverse arthropod taxa. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

    Science.gov (United States)

    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.

  8. Ecotoxicological risk of pharmaceuticals from wastewater treatment plants in Korea: occurrence and toxicity to Daphnia magna.

    Science.gov (United States)

    Han, Guk H; Hur, Hor G; Kim, Sang D

    2006-01-01

    The overall ecotoxicological effect of pharmaceutically active compounds (PhACs) detected in the effluents of Korean wastewater treatment plants (WWTPs) to Daphnia magna was investigated using biological and chemical analyses. The bioassay results showed median lethal concentrations and no-observed-effect concentrations ranging from a few to tens of ppm levels for nine PhACs in 48-h acute and 21-d chronic tests. The mixture effects of pharmaceuticals also were examined by other acute and chronic tests, which showed no significant toxicity despite a slightly increased combined effect of approximately twofold. The residual concentrations of nine PhACs were analyzed at concentrations ranging from 10 ng/L to 89 microg/L in the influents and from 10 ng/L to 11 microg/L in the effluents from four metropolitan cities in South Korea between January and November of 2004. Through repeated investigations of the influents and the effluents from different WWTPs, relatively higher removal efficiencies (23.9-91.3%) compared with those of previous surveys performed in other countries were observed for most pharmaceuticals, with the exception of acetaminophen (8.7%). The present study showed no significant risk effects of the effluents from WWTPs containing pharmaceuticals (i.e., hazard quotient risk assessment factor of 1,000 was applied. Therefore, it can be concluded that the potential risk of pharmaceuticals should be monitored carefully with more bioassay data, because many uncertainties still exist in the determination and toxicity of metabolites in water environments. No significant risk was observed, however, from the selected PhACs in the effluents from WWTPs discharged into surface waters.

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

    Science.gov (United States)

    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.

  10. Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Lange, de H.J.; Peeters, E.T.H.M.

    2011-01-01

    The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of

  11. The effect of pH on the uptake and toxicity of the bivalent weak base chloroquine tested on Salix viminalis and Daphnia magna

    DEFF Research Database (Denmark)

    Rendal, Cecilie; Kusk, Kresten Ole; Trapp, Stefan

    2011-01-01

    , and therefore a higher toxicity can be expected. The current study examines the pHdependent toxicity and bioaccumulation of the bivalent weak base chloroquine (pKa: 10.47 and 6.33, log KOW 4.67) tested on Salix viminalis (basket willow) and Daphnia magna (water flea). The transpiration rates of hydroponically...

  12. Critical evaluation and further development of methods for testing ecotoxicity at multiple pH using Daphnia magna and Pseudokirchneriella subcapitata

    DEFF Research Database (Denmark)

    Rendal, Cecilie; Trapp, Stefan; Kusk, Kresten Ole

    2012-01-01

    . This is supplemented by a series of experiments where toxicity and ability to stabilize pH of seven common buffering compounds was tested on Daphnia magna and Pseudokirchneriella subcapitata. We consider a buffer applicable at a given concentration if the pH drift is below 0.2 pH units, and if there are no toxic...

  13. Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)

    NARCIS (Netherlands)

    Lürling, M.; de Lange, H.J.; Peeters, E.T.H.M.

    2011-01-01

    The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of

  14. Effects of juvenile host density and food availability on adult immune response, parasite resistance and virulence in a Daphnia-parasite system.

    Directory of Open Access Journals (Sweden)

    Corine N Schoebel

    Full Text Available Host density can increase infection rates and reduce host fitness as increasing population density enhances the risk of becoming infected either through increased encounter rate or because host condition may decline. Conceivably, potential hosts could take high host density as a cue to up-regulate their defence systems. However, as host density usually covaries with food availability, it is difficult to examine the importance of host density in isolation. Thus, we performed two full-factorial experiments that varied juvenile densities of Daphnia magna (a freshwater crustacean and food availability independently. We also included a simulated high-density treatment, where juvenile experimental animals were kept in filtered media that previously maintained Daphnia at high-density. Upon reaching adulthood, we exposed the Daphnia to their sterilizing bacterial parasite, Pasteuria ramosa, and examined how the juvenile treatments influenced the likelihood and severity of infection (Experiment I and host immune investment (Experiment II. Neither juvenile density nor food treatments affected the likelihood of infection; however, well-fed hosts that were well-fed as juveniles produced more offspring prior to sterilization than their less well-fed counterparts. By contrast, parasite growth was independent of host juvenile resources or host density. Parasite-exposed hosts had a greater number of circulating haemocytes than controls (i.e., there was a cellular immune response, but the magnitude of immune response was not mediated by food availability or host density. These results suggest that density dependent effects on disease arise primarily through correlated changes in food availability: low food could limit parasitism and potentially curtail epidemics by reducing both the host's and parasite's reproduction as both depend on the same food.

  15. The protective roles of TiO2 nanoparticles against UV-B toxicity in Daphnia magna.

    Science.gov (United States)

    Liu, Jie; Wang, Wen-Xiong

    2017-03-22

    Aquatic environments are increasingly under environmental stress due to ultraviolet (UV) radiation and potential inputs of nanoparticles with intense application of nanotechnology. In this study, we investigated the interaction between UV-B radiation and titanium nanoparticles (TiO2-NPs) in a model freshwater cladoceran Daphnia magna. UV-B toxicity to Daphnia magna was examined when the daphnids were exposed to a range of TiO2-NPs concentrations with an initial 5 or 10min of 200μW/cm(2) UV-B radiation. In addition, UV-B toxicity was also examined in the presence of TiO2-NPs in the body of daphnids. Our results demonstrated that the daphnid mortality under UV-B radiation decreased significantly in the presence of TiO2-NPs both in the water and in the body, indicating that TiO2-NPs had some protective effects on D. magna against UV-B. Such protective effect was mainly caused by the blockage of UV-B by TiO2-NPs adsorption. UV-B produced reactive oxygen species (ROS) in the water and in the daphnids, which was not sufficient to cause mortality of daphnids over short periods of radiation. Previous studies focused on the effects of TiO2-NPs on the toxicity of total UV radiation, and did not attempt to differentiate the potential diverse roles of UV-A and UV-B. Our study indicated that TiO2-NPs may conversely protect the UV-B toxicity to daphnids.

  16. Sequence Conservation and Sexually Dimorphic Expression of the Ftz-F1 Gene in the Crustacean Daphnia magna.

    Directory of Open Access Journals (Sweden)

    Nur Syafiqah Mohamad Ishak

    Full Text Available Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1 are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males in response to environmental stimuli. Similar to that observed in Drosophila, D. magna Ftz-F1 (DapmaFtz-F1 produces two splicing variants, αFtz-F1 and βFtz-F1, which encode 699 and 777 amino acids, respectively. Both isoforms share a DNA-binding domain, a ligand-binding domain, and an AF-2 activation domain and differ only at the A/B domain. The phylogenetic position and genomic structure of DapmaFtz-F1 suggested that this gene has diverged from an ancestral gene common to branchiopod crustacean and insect Ftz-F1 genes. qRT-PCR showed that at the one cell and gastrulation stages, both DapmaFtz-F1 isoforms are two-fold more abundant in males than in females. In addition, in later stages, their sexual dimorphic expressions were maintained in spite of reduced expression. Time-lapse imaging of DapmaFtz-F1 RNAi embryos was performed in H2B-GFP expressing transgenic Daphnia, demonstrating that development of the RNAi embryos slowed down after the gastrulation stage and stopped at 30-48 h after ovulation. DapmaFtz-F1 shows high homology to insect Ftz-F1 orthologs based on its amino acid sequence and exon-intron organization. The sexually dimorphic expression of DapmaFtz-F1 suggests that it plays a role in environmental sex determination of D. magna.

  17. Sequence Conservation and Sexually Dimorphic Expression of the Ftz-F1 Gene in the Crustacean Daphnia magna.

    Science.gov (United States)

    Mohamad Ishak, Nur Syafiqah; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

    2016-01-01

    Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1) are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males in response to environmental stimuli. Similar to that observed in Drosophila, D. magna Ftz-F1 (DapmaFtz-F1) produces two splicing variants, αFtz-F1 and βFtz-F1, which encode 699 and 777 amino acids, respectively. Both isoforms share a DNA-binding domain, a ligand-binding domain, and an AF-2 activation domain and differ only at the A/B domain. The phylogenetic position and genomic structure of DapmaFtz-F1 suggested that this gene has diverged from an ancestral gene common to branchiopod crustacean and insect Ftz-F1 genes. qRT-PCR showed that at the one cell and gastrulation stages, both DapmaFtz-F1 isoforms are two-fold more abundant in males than in females. In addition, in later stages, their sexual dimorphic expressions were maintained in spite of reduced expression. Time-lapse imaging of DapmaFtz-F1 RNAi embryos was performed in H2B-GFP expressing transgenic Daphnia, demonstrating that development of the RNAi embryos slowed down after the gastrulation stage and stopped at 30-48 h after ovulation. DapmaFtz-F1 shows high homology to insect Ftz-F1 orthologs based on its amino acid sequence and exon-intron organization. The sexually dimorphic expression of DapmaFtz-F1 suggests that it plays a role in environmental sex determination of D. magna.

  18. Performance of standard media in toxicological assessments with Daphnia magna: chelators and ionic composition versus metal toxicity.

    Science.gov (United States)

    Loureiro, Cláudia; Castro, Bruno B; Pereira, Joana Luísa; Gonçalves, Fernando

    2011-01-01

    Fully artificial test media can increase reproducibility and standardization in ecotoxicological assessments, but there is still a lack of convergence among ecotoxicology laboratories in aquatic test media with respect to ionic composition, chelators, and organic supplements. We compared the performance of Daphnia magna in three widely-used reconstituted media. The tested media differed in composition: (a) ADaM, an artificial medium based in a synthetic sea salt, with no a priori known chelating properties; (b) ASTM hard water supplemented with algal extract, a semi-artificial medium with unknown chelating properties; and (c) M7, a complex artificial medium containing EDTA as a chelator. All three media were suitable for rearing D. magna (although performance in M7 was suboptimal) and acute EC(50) values for reference substances (3,4-DCA, K(2)Cr(2)O(7)) were similar between media. In acute exposures to Cu and Cd, daphniids were least sensitive when reared in M7, as expected due to metal chelation by EDTA. Daphnia sensitivity to Cd was low in ADaM. Thus, these two media were suboptimal for assessing the toxicity of some metals to D. magna in acute tests. We suggest that both the ionic composition of the medium and the presence of chelators should be taken into account when metal toxicity is concerned. Chronic toxicity profiles for Cu suggested a mild chelating effect of the algal extract in ASTM medium. Still, ASTM hard water persists as one of the most suitable media for acute toxicity assessments of metals and metal-contaminated samples.

  19. Surfactants decrease the toxicity of ZnO, TiO2 and Ni nanoparticles to Daphnia magna.

    Science.gov (United States)

    Oleszczuk, Patryk; Jośko, Izabela; Skwarek, Ewa

    2015-11-01

    The objective of the study was the estimation of the effect of surfactants on the toxicity of ZnO, TiO2 and Ni nanoparticles (ENPs) towards Daphnia magna. The effect of hexadecyltrimethylammonium bromide (CTAB), triton X-100 (TX100) and 4-dodecylbenzenesulfonic acid (SDBS) was tested. The Daphtoxkit F test (conforming to OECD Guideline 202 and ISO 6341) was applied for the toxicity testing. Both the surfactants and the ENPs were toxic to D. magna. The addition of ENPs to a solution of the surfactants caused a significant reduction of toxicity of ENPs. The range of reduction of the toxicity of the ENPs depended on the kind of the ENPs and their concentration in the solution, and also on the kind of surfactant. For nano-ZnO the greatest reduction of toxicity was caused by CTAB, while for nano-TiO2 the largest drop of toxicity was observed after the addition of TX100. In the case of nano-Ni, the effect of the surfactants depended on its concentration. Most probably the reduction of toxicity of ENPs in the presence of the surfactants was related with the formation of ENPs aggregates that inhibited the availability of ENPs for D. magna.

  20. A comparative study on the relationship between acetylcholinesterase activity and acute toxicity in Daphnia magna exposed to anticholinesterase insecticides.

    Science.gov (United States)

    Printes, Liane Biehl; Callaghan, Amanda

    2004-05-01

    Acetylcholinesterase (AChE) activity was measured in Daphnia magna that had been exposed to four organophosphates (OPs; parathion, chlorpyrifos, malathion, and acephate) and one carbamate (propoxur) for 48 h. These results were related to acute toxicity (median effective concentration [EC50] for immobility). For the four OPs, the EC50s were 7.03 pM, 3.17 pM, 10.56 pM, and 309.82 microM, respectively. The EC50 for propoxur was 449.90 pM. Reduction in AChE activity was directly related to an increase in immobility in all chemicals tested. However, the ratio between the EC50 and the AChE median inhibiting concentration ranged from 0.31 to 0.90. A 50% reduction in AChE activity generally was associated with detrimental effects on mobility. However, for acephate, high levels of AChE inhibition (70%) were observed in very low concentrations and were not associated with immobility. In addition, increasing the concentration of acephate further had a slight negative effect on AChE activity but a strong detrimental effect on mobility. Binding sites other than AChE possibly are involved in acephate toxicity to D. magna. Our findings demonstrate different associations between AChE inhibition and toxicity when different chemicals are compared. Therefore, the value of using AChE activity as a biomarker in D. magna will be dependent on the chemical tested.

  1. Phenanthrene Bioavailability and Toxicity to Daphnia magna in the Presence of Carbon Nanotubes with Different Physicochemical Properties.

    Science.gov (United States)

    Zindler, Florian; Glomstad, Berit; Altin, Dag; Liu, Jingfu; Jenssen, Bjørn M; Booth, Andy M

    2016-11-15

    Studies investigating the effect of carbon nanotubes (CNTs) on the bioavailability and toxicity of hydrophobic organic compounds in aquatic environments have generated contradictory results, and the influence of different CNT properties remains unknown. Here, the adsorption of the polycyclic aromatic hydrocarbon phenanthrene (70-735 μg/L) to five types of CNTs exhibiting different physical and chemical properties was studied. The CNTs were dispersed in the presence of natural organic matter (nominally 20 mg/L) in order to increase the environmental relevance of the study. Furthermore, the bioavailability and toxicity of phenanthrene to Daphnia magna in the absence and presence of dispersed CNTs was investigated. Both CNT dispersion and adsorption of phenanthrene appeared to be influenced by CNT physical properties (diameter and specific surface area). However, dispersion and phenanthrene adsorption was not influenced by CNT surface chemical properties (surface oxygen content), under the conditions tested. Based on nominal phenanthrene concentrations, a reduction in toxicity to D. magna was observed during coexposure to phenanthrene and two types of CNTs, while for the others, no influence on phenanthrene toxicity was observed. Based on freely dissolved concentrations, however, an increased toxicity was observed in the presence of all CNTs, indicating bioavailability of CNT-adsorbed phenanthrene to D. magna.

  2. TiO2 Nanoparticle Uptake by the Water Flea Daphnia magna via Different Routes is Calcium-Dependent.

    Science.gov (United States)

    Tan, Ling-Yan; Huang, Bin; Xu, Shen; Wei, Zhong-Bo; Yang, Liu-Yan; Miao, Ai-Jun

    2016-07-19

    Calcium plays versatile roles in aquatic ecosystems. In this study, we investigated its effects on the uptake of polyacrylate-coated TiO2 nanoparticles (PAA-TiO2-NPs) by the water flea (cladoceran) Daphnia magna. Particle distribution in these daphnids was also visualized using synchrotron radiation-based micro X-ray fluorescence spectroscopy, transmission electron microscopy, and scanning electron microscopy. At low ambient Ca concentrations in the experimental medium ([Ca]dis), PAA-TiO2-NPs were well dispersed and distributed throughout the daphnid; the particle concentration was highest in the abdominal zone and the gut, as a result of endocytosis and passive drinking of the nanoparticles, respectively. Further, Ca induced PAA-TiO2-NP uptake as a result of the increased Ca influx. At a high [Ca]dis, the PAA-TiO2-NPs formed micrometer-sized aggregates that were ingested by D. magna and concentrated only in its gut, independent of the Ca influx. Our results demonstrated the multiple effects of Ca on nanoparticle bioaccumulation. Specifically, well-dispersed nanoparticles were taken up by D. magna through endocytosis and passive drinking whereas the uptake of micrometer-sized aggregates relied on active ingestion.

  3. Early embryonic expression of a putative ecdysteroid-phosphate phosphatase in the water flea, Daphnia magna (Cladocera: Daphniidae).

    Science.gov (United States)

    Asada, Miki; Kato, Yasuhiko; Matsuura, Tomoaki; Watanabe, Hajime

    2014-01-01

    Ecdysteroids, known as molting hormones, play central roles in the onset of molting, metamorphosis, and reproduction in arthropods. The ecdysteroids stored in eggs also play an important role in embryogenesis. In insects, ecdysteroids are stored as phosphate esters, which are converted to an active form by ecdysteroid-phosphate phosphatase (EPPase). Although EPPase is believed to be widely conserved in the Ecdysozoa, little is known about its expression in clades other than Insecta. In this study, we cloned a putative EPPase gene from a small fresh water crustacean known as a water flea, Daphnia magna Straus (Cladocera: Daphniidae), and examined its expression during embryogenesis. The amino acid sequence of the putative crustacean EPPase cDNA showed high similarity to insect EPPase and human suppressor of T-cell receptor signaling-1. We also found that the D. magna EPPase was highly expressed during early embryogenesis; its expression rapidly decreased 6 h after oviposition. This timing corresponds to the onset of organogenesis in D. magna. The expression of EPPase could not be detected in diapaused eggs. This is the first report of an EPPase from crustaceans, and the results suggest that the function of EPPase is conserved between insects and crustaceans. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

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

    Science.gov (United States)

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

    2007-08-30

    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 3 h 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 3.00 microg 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 (0.4 mg/L) resulted in a approximately 50% decrease in toxicity while the addition of sulfide (75.4 nM) 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.

  5. TALEN-mediated knock-in via non-homologous end joining in the crustacean Daphnia magna.

    Science.gov (United States)

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

    2016-11-07

    Transcription activator-like effector nucleases (TALENs) are versatile tools that enable the insertion of DNA into different organisms. Here, we confirmed TALEN-mediated knock-in via non-homologous end joining in the crustacean Daphnia magna, a model organism for ecological and toxicological genomics. We tested two different TALENs, ey1 TALEN and ey2 TALEN, both of which target the eyeless locus. The donor DNA plasmid, harbouring the H2B-GFP reporter gene, was designed to contain both TALEN target sites and was co-injected with each TALEN mRNA into eggs. The ey1 TALEN and ey2 TALEN constructs both resulted in H2B-GFP expression in Daphnia with a germline transmission efficiency of 3%. Of the three transgenic animals generated, two had donor DNA at the targeted genomic site, which suggested concurrent cleavage of the injected plasmid DNA and genome DNA. The availability of such tools that are capable of targeted knock-in of foreign genes will be extremely useful for advancing the knowledge of gene function and contribute to an increased understanding of functional genomics in Daphnia.

  6. Chitobiase activity as an indicator of altered survival, growth and reproduction in Daphnia pulex and Daphnia magna (Crustacea: Cladocera) exposed to spinosad and diflubenzuron.

    Science.gov (United States)

    Duchet, Claire; Mitie Inafuku, Marília; Caquet, Thierry; Larroque, Michel; Franquet, Evelyne; Lagneau, Christophe; Lagadic, Laurent

    2011-05-01

    Chitobiase is involved in exoskeleton degradation and recycling during the moulting process in arthropods. In aquatic species, the moulting fluid is released into the aqueous environment, and chitobiase activity present therein can be used to follow the dynamics of arthropod populations. Here, chitobiase activity was used for monitoring the impact of mosquito candidate larvicides on Daphnia pulex and Daphnia magna under laboratory conditions. Both species were exposed to spinosad (2, 4, 8 μg L(-1)) and diflubenzuron (0.2, 0.4, 0.8 μg L(-1)) for 14 days. Bacillus thuringiensis var. israelensis (Bti; 0.25, 0.5, 1 μL L(-1)) was used as the reference larvicide. Chitobiase activity, adult survival, individual growth and fecundity, expressed as the number of neonates produced, were measured every 2 days. Average Exposure Concentrations of spinosad were ten-fold lower than the nominal concentrations, whereas only a slight deviation was observed for diflubenzuron. In contrast to Bti, spinosad and diflubenzuron significantly affected both species in terms of adult survival, and production of neonates. As compared to D. pulex, D. magna was more severely affected by diflubenzuron, at low and medium concentrations, with reduced adult growth and much lower chitobiase activity. Chitobiase activity was positively correlated with the individual body length, number of neonates produced between two consecutive observation dates, and number of females and neonates. In addition, the significant positive correlations between chitobiase activity measured on the last sampling date before the first emission of neonates and the cumulative number of neonates produced during the whole observation period strongly support the potential of the activity of this chitinolytic enzyme as a proxy for assessing the dynamics of arthropod populations exposed to larvicides used for mosquito control.

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

    Directory of Open Access Journals (Sweden)

    Martin Ogonowski

    Full Text Available 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

  8. Metabolomics reveals energetic impairments in Daphnia magna exposed to diazinon, malathion and bisphenol-A

    Energy Technology Data Exchange (ETDEWEB)

    Nagato, Edward G.; Simpson, André J.; Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca

    2016-01-15

    Highlights: • Metabolomics detected shifts with sub-lethal exposure to contaminants. • Diazinon and malathion induced comparable, non-linear responses. • Bisphenol-A resulted in energy impairment. • Overall, insight into sub-lethal toxicity was garnered using NMR-based metabolomics. - Abstract: {sup 1}H nuclear magnetic resonance (NMR)-based metabolomics was used to study the response of Daphnia magna to increasing sub-lethal concentrations of either an organophosphate (diazinon or malathion) or bisphenol-A (BPA). Principal component analysis (PCA) of {sup 1}H NMR spectra were used to screen metabolome changes after 48 h of contaminant exposure. The PCA scores plots showed that diazinon exposures resulted in aberrant metabolomic profiles at all exposure concentrations tested (0.009–0.135 μg/L), while for malathion the second lowest (0.08 μg/L) and two highest exposure concentrations (0.32 μg/L and 0.47 μg/L) caused significant shifts from the control. Individual metabolite changes for both organophosphates indicated that the response to increasing exposure was non-linear and described perturbations in the metabolome that were characteristic of the severity of exposure. For example, intermediate concentrations of diazinon (0.045 μg/L and 0.09 μg/L) and malathion (0.08 μg/L) elicited a decrease in amino acids such as leucine, valine, arginine, glycine, lysine, glutamate, glutamine, phenylalanine and tyrosine, with concurrent increases in glucose and lactate, suggesting a mobilization of energy resources to combat stress. At the highest exposure concentrations for both organophosphates there was evidence of a cessation in metabolic activity, where the same amino acids increased and glucose and lactate decreased, suggesting a slowdown in protein synthesis and depletion of energy stocks. This demonstrated a similar response in the metabolome between two organophosphates but also that intermediate and severe stress levels could be differentiated by

  9. Acute toxicity of fire control chemicals to Daphnia magna (Straus) and Selenastrum capricornutum (Printz).

    Science.gov (United States)

    McDonald, S F; Hamilton, S J; Buhl, K J; Heisinger, J F

    1996-02-01

    Acute toxicity tests were conducted exposing Daphnia magna Straus (daphnid) in soft and hard reconstituted waters (hardness 42 and 162 mg/liter as CaCO3, respectively), and Selenastrum capricornutum Printz (algae) in ASTM algal assay medium (hardness 15 mg/liter as CaCO3) to fire retardants Fire-Trol GTS-R, Fire-Trol LCG-R, and Phos-Chek D75-F, and foam suppressants Phos-Check WD-881 and Silv-Ex. The chemicals were slightly toxic to practically harmless to daphnids and moderately toxic to algae. Water quality did not consistently alter the toxicity of the test chemicals to daphnids. The most toxic chemical to daphnids was Silv-Ex (48-hr EC50 7 mg/liter in soft and hard waters), whereas the least toxic chemical to daphnids was Fire-Trol LCG-R (48-hr EC50 848 mg/liter in soft water, 813 mg/liter in hard water). The most toxic chemical to algae was Fire-Trol LCG-R (96-hr IC50 10 mg/liter), and the least toxic chemical was Phos-Chek D75-F (96-hr IC50 79 mg/liter). Un-ionized ammonia concentrations near the EC50 or IC50 value in tests with the Fire-Trol compounds were frequently equal to or above reported LC50 un-ionized ammonia concentrations. Un-ionized ammonia concentrations in tests with Phos-Chek D75-F were low, thus other toxic components present in the compounds probably contributed to the toxicity. When compared to the daphnids tested in ASTM soft water, the Fire-Trol compounds were most toxic to algae, whereas Phos-Chek D75-F and the foam suppressants were most toxic to daphnids. The results of these tests are comparable to those obtained from research conducted in other laboratories with the same species and similar chemicals. Accidental entry of fire-fighting chemicals into aquatic environments could adversely affect algae and aquatic invertebrates, thus disrupting ecosystem function.

  10. Effects of three diamides (chlorantraniliprole, cyantraniliprole and flubendiamide) on life history, embryonic development and oxidative stress biomarkers of Daphnia magna.

    Science.gov (United States)

    Cui, Feng; Chai, Tingting; Qian, Le; Wang, Chengju

    2017-02-01

    The diamides have become one of the most promising new classes of insecticides. In this study, we evaluated the toxicity of three diamides (chlorantraniliprole, cyantraniliprole and flubendiamide) to Daphnia magna. The acute toxicity test showed that the 48-h EC50 of chlorantraniliprole, cyantraniliprole and flubendiamide were 8.5, 23.9 and 63.5 μg/L, respectively. Biochemical measurements revealed a significant increase in reactive oxygen species (ROS) in D. magna after acute exposure to the three diamides. A significant decrease in activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) was observed, which was consistent with the down-regulated transcription of antioxidant genes sod and gpx. Catalase (CAT) activity exhibited a significant increase while the related gene cat showed no obvious change in daphnids acutely exposed to the three diamides. The chronic test revealed that the three diamides could cause lethal and sub-lethal effects on daphnids within constricted range of concentrations at μg/L level. The 21-d EC50 of chlorantraniliprole, cyantraniliprole and flubendiamide for mobility were 5.0, 13.6 and 36.8 μg/L, respectively. The chronic LOEC of chlorantraniliprole, cyantraniliprole and flubendiamide based on survival, growth and reproduction of D. magna were 4.05, 10.24 and 19.36 μg/L, respectively. Moreover, these three diamides can induce severe developmental abnormalities in D. magna embryos including underdeveloped second antennae, curved tail spine and abnormal body region after acute exposure and the 48-h EC50 were 6.2, 14.1 and 30.8 μg/L for chlorantraniliprole, cyantraniliprole and flubendiamide respectively. Our findings indicate that even low levels of diamides can pose ecological risks to aquatic ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effects of Cylindrospermopsis raciborskii and Aphanizomenon ovalisporum (cyanobacteria) ingestion on Daphnia magna midgut and associated diverticula epithelium

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Isabel C.G. [Centro Interdisciplinar de Investigacao Marinha e Ambiental, Rua dos Bragas 177-289, 4050-123 Porto (Portugal)]. E-mail: isabelnogueira@ciimar.up.pt; Lobo-da-Cunha, Alexandre [Centro Interdisciplinar de Investigacao Marinha e Ambiental, Rua dos Bragas 177-289, 4050-123 Porto (Portugal); Laboratorio de Biologia Celular, Instituto de Ciencias Biomedicas Abel Salazar (ICBAS), Universidade do Porto, Largo Abel Salazar 2, 4099-003 Porto (Portugal); Vasconcelos, Vitor M. [Centro Interdisciplinar de Investigacao Marinha e Ambiental, Rua dos Bragas 177-289, 4050-123 Porto (Portugal); Departamento de Zoologia e Antropologia, Faculdade de Ciencias, Universidade do Porto, Praca Gomes Teixeira, 4099-002 Porto (Portugal)

    2006-11-16

    This article reports a light and electron microscopy investigation of the effects of Cylindrospermopsis raciborskii and Aphanizomenon ovalisporum ingestion on midgut and associated digestive diverticula of Daphnia magna. Additionally, survivorship and growth effects caused by feeding on cyanobacteria were assessed. Three cyanobacteria were used in the experiments: cylindrospermopsin (CYN)-producing C. raciborskii, CYN-producing A. ovalisporum and non-CYN-producing C. raciborskii. In order to discriminate between the alterations due to the low nutritional value of cyanobacteria and toxic effects, a control group was fed on the chlorophyte Ankistrodesmus falcatus and another control group was not fed. In the chlorophyte fed control, the epithelium lining the midgut and associated diverticula is mainly formed by strongly stained cells with an apical microvilli border. Nevertheless, unstained areas in which cell lyses had occurred were also observed. In the unfed control, the unstained areas became predominant due to an increment of cell lyses. All individuals fed on CYN-producing A. ovalisporum and some of those fed on non-CYN-producing C. raciborskii appear similar to the unfed control. However, some individuals fed on non-CYN-producing C. raciborskii showed similarities with the fed control. In contrast, the midgut and digestive diverticula of D. magna fed on CYN-producing C. raciborskii showed a widespread dissociation of epithelial cells, associated with severe intracellular disorganization, but cell lysis was less evident than in controls. These alterations cannot be attributed to CYN, because those effects were not induced by CYN-producing A. ovalisporum. Therefore, data suggest the production of another unidentified active metabolite by CYN-producing C. raciborskii, responsible for the disruption of cell adhesion in the epithelium of D. magna digestive tract. Data also show that the tested cyanobacteria are inadequate as food to D. magna, due to low nutritional

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

    Science.gov (United States)

    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 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.

  13. Potential impact of low-concentration silver nanoparticles on predator-prey interactions between predatory dragonfly nymphs and Daphnia magna as a prey.

    Science.gov (United States)

    Pokhrel, Lok R; Dubey, Brajesh

    2012-07-17

    This study investigated the potential impacts of low-concentration citrate-coated silver nanoparticles (citrate-nAg; 2 μg L(-1) as total Ag) on the interactions of Daphnia magna Straus (as a prey) with the predatory dragonfly ( Anax junius : Odonata) nymph using the behavioral, survival, and reproductive end points. Four different toxicity bioassays were evaluated: (i) horizontal migration; (ii) vertical migration; (iii) 48 h survival; and (iv) 21 day reproduction; using four different treatment combinations: (i) Daphnia + citrate-nAg; (ii) Daphnia + predator; (iii) Daphnia + citrate-nAg + predator; and (iv) Daphnia only (control). Daphnia avoided the predators using the horizontal and vertical movements, indicating that Daphnia might have perceived a significant risk of predation. However, with citrate-nAg + predator treatment, Daphnia response did not differ from control in the vertical migration test, suggesting that Daphnia were unable to detect the presence of predator with citrate-nAg treatment and this may have potential implication on daphnids population structure owing to predation risk. The 48 h survival test showed a significant mortality of Daphnia individuals in the presence of predators, with or without citrate-nAg, in the test environment. Average reproduction of daphnids increased by 185% with low-concentration citrate-nAg treatment alone but was severely compromised in the presence of predators (decreased by 91.3%). Daphnia reproduction was slightly enhanced by approximately 128% with citrate-nAg + predator treatment. Potential mechanisms of these differential effects of low-concentration citrate-nAg, with or without predators, are discussed. Because silver dissolution was minimal, the observed toxicity could not be explained by dissolved Ag alone. These findings offer novel insights into how exposure to low-concentration silver nanoparticles could influence predator-prey interactions in the fresh water systems.

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

    Science.gov (United States)

    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).

  15. Not all that glitters is gold - Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artefacts

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie

    2016-01-01

    techniques are used to investigate internalization of 10 nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells upon 24h exposure and outline potential artefacts, i.e. high contract precipitates from sample preparation related to these techniques. Light sheet microscopy confirmed...... accumulation of gold nanoparticles in the gut lumen. Scanning transmission electron microscopy and elemental analysis revealed gold nanoparticles attached to the microvilli of gut cells. Interestingly, the peritrophic membrane appeared to act as a semipermeable barrier between the lumen and the gut epithelium......, permitting only single particles through. Structures resembling nanoparticles were also observed inside gut cells. As elemental analysis could not verify these to be gold they were likely artifacts from the preparation, such as osmium and iron. Importantly, gold nanoparticles were in fact found inside...

  16. The effect of food on the respiration rates of Daphnia magna using a flow-through system

    Directory of Open Access Journals (Sweden)

    Claire Schmoker

    2003-09-01

    Full Text Available Respiration rates and gut fluorescence of the cladoceran Daphnia magna were studied using a flow-through system. This open system has the advantage of introducing food or producing a starvation effect during the course of the experiment. Severe variations in respiratory rates were observed in relation to the presence or absence of food, indicating short-term variability. Organisms kept starved or at low food for a long period (15-20 h responded to a sudden increase in food by increasing their respiration rates three- to four-fold in parallel with their gut content. A significant relationship between gut fluorescence and respiration rates was observed, suggesting that feeding and the related swimming activity were responsible for the observed metabolic variability.

  17. Effect of subcellular distribution on nC₆₀ uptake and transfer efficiency from Scenedesmus obliquus to Daphnia magna.

    Science.gov (United States)

    Chen, Qiqing; Hu, Xialin; Yin, Daqiang; Wang, Rui

    2016-06-01

    The potential uptake and trophic transfer ability of nanoparticles (NPs) in aquatic organisms have not been well understood yet. There has been an increasing awareness of the subcellular fate of NPs in organisms, but how the subcellular distribution of NPs subsequently affects the trophic transfer to predator remains to be answered. In the present study, the food chain from Scenedesmus obliquus to Daphnia magna was established to simulate the trophic transfer of fullerene aqueous suspension (nC60). The nC60 contaminated algae were separated into three fractions: cell wall (CW), cell organelle (CO), and cell membrane (CM) fractions, and we investigated the nC60 uptake amounts and trophic transfer efficiency to the predator through dietary exposure to algae or algal subcellular fractions. The nC60 distribution in CW fraction of S. obliquus was the highest, following by CO and CM fractions. nC60 uptake amounts in D. magna were found to be mainly relative to the NPs' distribution in CW fraction and daphnia uptake ability from CW fraction, whereas the nC60 trophic transfer efficiency (TE) were mainly in accordance with the transfer ability of NPs from the CO fraction. CW fed group possessed the highest uptake amount, followed by CO and CM fed groups, but the presence of humic acid (HA) significantly decreased the nC60 uptake from CW fed group. The CO fed groups acquired high TE values for nC60, while CM fed groups had low TE values. Moreover, even though CW fed group had a high TE value; it decreased significantly with the presence of HA. This study contributes to the understanding of fullerene NPs' dietary exposure to aquatic organisms, suggesting that NPs in different food forms are not necessarily equally trophically available to the predator. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Uptake visualization of deltamethrin by NanoSIMS and acute toxicity to the water flea Daphnia magna.

    Science.gov (United States)

    Eybe, T; Bohn, T; Audinot, J N; Udelhoven, T; Cauchie, H M; Migeon, H N; Hoffmann, L

    2009-06-01

    The objective of this study was to investigate the uptake of deltamethrin, an insecticide, by Daphnia magna neonates by SIMS and to compare these findings with results based on established toxicity tests. Young daphnids (aged <24 h) were exposed to 0, 50 and 200 microg L(-1) (ppb) deltamethrin. Mobile, immobile and dead animals were enumerated after 24 and 48 h following OECD 202 [OECD 202, 2004. Daphnia sp., acute immobilisation test, guideline for testing of chemicals] guidelines. The animals were embedded in epoxy resin, cut into semi-thin sections (500 nm) and placed on silicon supporters. NanoSIMS 50 (Cameca) images were made from tissues of the intestine for carbon, nitrogen (measured as CN), phosphorus and bromine. To distinguish between relative concentrations of bromine in the guts from different exposure concentrations of deltamethrin, a carbon normalization method was carried out. Both deltamethrin concentrations and time showed a significant effect on immobilization and mortality of the daphnids (P<0.0001). Bromine from deltamethrin could be visualized by NanoSIMS in all exposed gut tissues (gut wall, microvilli layer, perithropic membrane). Highest deltamethrin concentrations following (12)C normalization were found in animals exposed to 200 microg L(-1) deltamethrin, followed by 50 microg L(-1) and the control. NanoSIMS 50 was successfully used as a supplemental technique for elucidating the relation between the uptake and localization of deltamethrin and its toxicity to D. magna. These results highlight the potential usefulness of NanoSIMS to detect marker elements of xenobiotic compounds within exposed organisms, to compare relative exposure concentrations, and to locate these compounds at their original tissue location.

  19. Importance of suspended sediment (SPS) composition and grain size in the bioavailability of SPS-associated pyrene to Daphnia magna.

    Science.gov (United States)

    Xia, Xinghui; Zhang, Xiaotian; Zhou, Dong; Bao, Yimeng; Li, Husheng; Zhai, Yawei

    2016-07-01

    Hydrophobic organic compounds (HOCs) tend to associate with suspended sediment (SPS) in aquatic environments; the composition and grain size of SPS will affect the bioavailability of SPS-associated HOCs. However, the bioavailability of HOCs sorbed on SPS with different compositions and grain sizes is not well understood. In this work, passive dosing devices were made to control the freely dissolved concentration of pyrene, a typical HOC, in the exposure systems. The effect of pyrene associated with amorphous organic carbon (AOC), black carbon (BC), and minerals of SPS with grain sizes of 0-50 μm and 50-100 μm on the immobilization and enzymatic activities of Daphnia magna was investigated to quantify the bioavailability of pyrene sorbed on SPS with different grain sizes and compositions. The results showed that the contribution of AOC-, BC-, and mineral-associated pyrene to the total bioavailability of SPS-associated pyrene was approximately 50%-60%, 10%-29%, and 20%-30%, respectively. The bioavailable fraction of pyrene sorbed on the three components of SPS was ordered as AOC (22.4%-67.3%) > minerals (20.1%-46.0%) > BC (9.11%-16.8%), and the bioavailable fraction sorbed on SPS of 50-100 μm grain size was higher than those of 0-50 μm grain size. This is because the SPS grain size will affect the ingestion of SPS and the SPS composition will affect the desorption of SPS-associated pyrene in Daphnia magna. According to the results obtained in this study, a model has been developed to calculate the bioavailability of HOCs to aquatic organisms in natural waters considering both SPS grain size and composition.

  20. Toxicity to Daphnia magna and Vibrio fischeri of Kraft bleach plant effluents treated by catalytic wet-air oxidation.

    Science.gov (United States)

    Pintar, Albin; Besson, Michèle; Gallezot, Pierre; Gibert, Janine; Martin, Dominique

    2004-01-01

    Two Kraft-pulp bleaching effluents from a sequence of treatments which include chlorine dioxide and caustic soda were treated by catalytic wet-air oxidation (CWAO) at T=463 K in trickle-bed and batch-recycle reactors packed with either TiO2 extrudates or Ru(3 wt%)/TiO2 catalyst. Chemical analyses (TOC removal, color, HPLC) and bioassays (48-h and 30-min acute toxicity tests using Daphnia magna and Vibrio fischeri, respectively) were used to get information about the toxicity impact of the starting effluents and of the treated solutions. Under the operating conditions, complex organic compounds are mostly oxidized into carbon dioxide and water, along with short-chain carboxylic acids. Bioassays were found as a complement to chemical analyses for ensuring the toxicological impact on the ecosystem. In spite of a large decrease of TOC, the solutions of end products were all more toxic to Daphnia magna than the starting effluents by factors ranging from 2 to 33. This observation is attributed to the synergistic effects of acetic acid and salts present in the solutions. On the other hand, toxicity reduction with respect to Vibrio fischeri was achieved: detoxification factors greater than unity were measured for end-product solutions treated in the presence of the Ru(3 wt%)/TiO2 catalyst, suggesting the absence of cumulative effect for this bacteria, or a lower sensitivity to the organic acids and salts. Bleach plant effluents treated by the CWAO process over the Ru/TiO2 catalyst were completely biodegradable.

  1. Exposure to D2-like dopamine receptor agonists inhibits swimming in Daphnia magna.

    Science.gov (United States)

    Barrozo, Enrico R; Fowler, David A; Beckman, Matthew L

    2015-10-01

    Daphnia are freshwater crustaceans that have been used for decades in ecotoxicology research. Despite the important role that Daphnia have played in environmental toxicology studies, very little is known about the neurobiology of Daphnia. Although many studies have investigated the swimming movements of these "water fleas", few studies have examined the underlying neurochemical basis for these movements. To characterize the locomotor effect of drugs in Daphnia, a two-dimensional video imaging tool was developed and animal tracking was performed with freely available software, CTRAX. Due to the central role that dopamine plays in the movement of animals, we sought to determine the role of dopamine receptor signaling in Daphnia movement by characterizing the effect of ten drugs that are agonists or antagonists of dopamine receptors. At 1, 2, and 6h of treatment with a 10μM drug, several dopamine receptor agonists with documented effects on the D2-like class of receptors decreased the movement. Further, we determined behavioral inhibition values (IC50) at 1h of treatment for (1R,3S)-1-(aminomethyl)-3-phenyl-3,4-dihydro-1H-isochromene-5,6-diol (A68930) to be 1.4μM and for bromocriptine to be 6.6μM. This study describes a new method to study Daphnia swimming and establishes this organism as a useful model for studies of dopaminergic signaling. Specifically, this study shows that a dopamine receptor signaling pathway, mediated by putative D2-like receptors, is involved in the control of Daphnia swimming behavior. Due to its ease of use and its rich motor program we propose that Daphnia should be considered for future studies of dopamine neuron toxicity and protection. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Temperature-dependent effect of filamentous cyanobacteria on Daphnia magna life history traits

    OpenAIRE

    Dawidowicz, Piotr; Joanna ŁOŚ; Anna BEDNARSKA

    2011-01-01

    Filamentous cyanobacteria are unsuitable food for Daphnia due to their poor manageability, poor nutritional value and, in some cases, toxicity. As the strength of harmful effects of cyanobacteria on filter-feeding zooplankton is temperature dependent, the global warming scenarios for eutrophic lakes in temperate zone might include an escalated suppression of Daphnia populations caused by the presence of cyanobacterial filaments. To test this assumption, we conducted life-table experiments wit...

  3. Phototoxicology. 1. Light-enhanced toxicity of TNT and some related compounds to Daphnia magna and Lytechinus variagatus embryos.

    Science.gov (United States)

    Davenport, R; Johnson, L R; Schaeffer, D J; Balbach, H

    1994-02-01

    Many environmental pollutants interact with solar near-ultraviolet (nuv) light in a manner which greatly increases their toxic effects. The phenomenon of light-mediated toxicity (phototoxicity) is only now becoming generally recognized to any significant degree. Manufacture of, and loading munitions with, the explosive 2,4,6-trinitrotoluene (TNT) in past decades caused contamination of soils and sediments at levels exceeding 1000 ppm and of waters at levels near saturation (100 ppm). Manufacture of TNT produces numerous nitrated by-products, and most of these compounds, including TNT, can be metabolized by many species, including bacteria, fungi, plants, and mammals. This study investigated the phototoxicity of TNT, and 2,3-, 2,4-, 2,6-, and 3,4-dinitrotoluene (DNT) and -diaminotoluene (DAT), and the major metabolites 2-amino-4,6-dinitrotoluene (2A) and 4-amino-2,6-dinitrotoluene (4A), to Daphnia magna (acute toxicity) and Lytechinus variagatus (sea urchin) embryos (subacute, developmental toxicity). Most of the compounds were weakly toxic or nontoxic in the dark. All were phototoxic to sea urchins. In D. magna, 2,3- and 3,4-DNT/DAT and 4A were not toxic but were phototoxic, and 2A was toxic and phototoxic; the other isomers were not toxic or phototoxic to this species.

  4. Larvicidal activity of Myrtaceae essential oils and their components against Aedes aegypti, acute toxicity on Daphnia magna, and aqueous residue.

    Science.gov (United States)

    Park, Hye-Mi; Kim, Junheon; Chang, Kyu-Sik; Kim, Byung-Seok; Yang, Yu-Jung; Kim, Gil-Hah; Shin, Sang-Chul; Park, Il-Kwon

    2011-03-01

    The larvicidal activity of 11 Myrtaceae essential oils and their constituents was evaluated against Aedes aegypti L. Of the 11, Melaleuca linariifolia Sm., Melaleuca dissitiflora F. Muell., Melaleuca quinquenervia (Cav.) S. T. Blake, and Eucalyptus globulus Labill oils at 0.1 mg/ml exhibited > or = 80% larval mortality. At this same concentration, the individual constituents tested, allyl isothiocyanate, alpha-terpinene, p-cymene, (+)-limonene, (-)-limonene, gamma-terpinene, and (E)-nerolidol, resulted in > or = 95% mortality. We also tested the acute toxicity of these four active oils earlier mentioned and their constituents against Daphnia magna Straus. M. linariifolia and allyl isothiocyanate was the most toxic to D. magna. Twodays after treatment, residues of M. dissitiflora, M. linariifolia, M. quinquenervia, and E. globulus oils in water were 55.4, 46.6, 32.4, and 14.8%, respectively. Less than 10% of allyl isothiocyanate, alpha-terpinene, p-cymene, (-)-limonene, (+)-limonene, and gamma-terpinene was detected in the water at 2 d after treatment. Our results indicated that oils and their constituents could easily volatilize in water within a few days after application, thus minimizing their effect on the aqueous ecosystem. Therefore, Myrtaceae essential oils and their constituents could be developed as control agents against mosquito larvae.

  5. Exposure medium: key in identifying free Ag+ as the exclusive species of silver nanoparticles with acute toxicity to Daphnia magna.

    Science.gov (United States)

    Shen, Mo-Hai; Zhou, Xiao-Xia; Yang, Xiao-Ya; Chao, Jing-Bo; Liu, Rui; Liu, Jing-Fu

    2015-04-10

    It is still not very clear what roles the various Ag species play in the toxicity of silver nanoparticles (AgNPs). In this study, we found that traditional exposure media result in uncontrollable but consistent physicochemical transformation of AgNPs, causing artifacts in determination of median lethal concentration (LC50) and hindering the identification of Ag species responsible for the acute toxicity of AgNPs to Daphnia magna. This obstacle was overcome by using 8 h exposure in 0.1 mmol L(-1) NaNO3 medium, in which we measured the 8-h LC50 of seven AgNPs with different sizes and coatings, and determined the concentrations of various Ag species. The LC50 as free Ag(+) of the seven AgNPs (0.37-0.44 μg L(-1)) agreed very well with that of AgNO3 (0.40 μg L(-1)), and showed the lowest value compared to that as total Ag, total Ag(+), and dissolved Ag, demonstrating free Ag(+) is exclusively responsible for the acute toxicity of AgNPs to D. magna, while other Ag species in AgNPs have no contribution to the acute toxicity. Our results demonstrated the great importance of developing appropriate exposure media for evaluating risk of nanomaterials.

  6. The interactive effects of ammonia and microcystin on life-history traits of the cladoceran Daphnia magna: synergistic or antagonistic?

    Directory of Open Access Journals (Sweden)

    Zhou Yang

    Full Text Available The occurrence of Microcystis blooms is a worldwide concern that has caused numerous adverse effects on water quality and lake ecology. Elevated ammonia and microcystin concentrations co-occur during the degradation of Microcystis blooms and are toxic to aquatic organisms; we studied the relative and combined effects of these on the life history of the model organism Daphnia magna. Ammonia and microcystin-LR treatments were: 0, 0.366, 0.581 mg L(-1 and 0, 10, 30, 100 µg L(-1, respectively. Experiments followed a fully factorial design. Incubations were 14 d and recorded the following life-history traits: number of moults, time to first batch of eggs, time to first clutch, size at first batch of eggs, size at first clutch, number of clutches per female, number of offspring per clutch, and total offspring per female. Both ammonia and microcystin were detrimental to most life-history traits. Interactive effects of the toxins occurred for five traits: the time to first batch of eggs appearing in the brood pouch, time to first clutch, size at first clutch, number of clutches, and total offspring per female. The interactive effects of ammonia and microcystin appeared to be synergistic on some parameters (e.g., time to first eggs and antagonistic on others (e.g., total offspring per female. In conclusion, the released toxins during the degradation of Microcystis blooms would result, according to our data, in substantially negative effect on D. magna.

  7. Exposure Medium: Key in Identifying Free Ag+ as the Exclusive Species of Silver Nanoparticles with Acute Toxicity to Daphnia magna

    Science.gov (United States)

    Shen, Mo-Hai; Zhou, Xiao-Xia; Yang, Xiao-Ya; Chao, Jing-Bo; Liu, Rui; Liu, Jing-Fu

    2015-04-01

    It is still not very clear what roles the various Ag species play in the toxicity of silver nanoparticles (AgNPs). In this study, we found that traditional exposure media result in uncontrollable but consistent physicochemical transformation of AgNPs, causing artifacts in determination of median lethal concentration (LC50) and hindering the identification of Ag species responsible for the acute toxicity of AgNPs to Daphnia magna. This obstacle was overcome by using 8 h exposure in 0.1 mmol L-1 NaNO3 medium, in which we measured the 8-h LC50 of seven AgNPs with different sizes and coatings, and determined the concentrations of various Ag species. The LC50 as free Ag+ of the seven AgNPs (0.37-0.44 μg L-1) agreed very well with that of AgNO3 (0.40 μg L-1), and showed the lowest value compared to that as total Ag, total Ag+, and dissolved Ag, demonstrating free Ag+ is exclusively responsible for the acute toxicity of AgNPs to D. magna, while other Ag species in AgNPs have no contribution to the acute toxicity. Our results demonstrated the great importance of developing appropriate exposure media for evaluating risk of nanomaterials.

  8. Protective effects of ectoine on behavioral, physiological and biochemical parameters of Daphnia magna subjected to hydrogen peroxide.

    Science.gov (United States)

    Bownik, Adam; Stępniewska, Zofia

    2015-04-01

    Ectoine (ECT) is an osmoprotectant produced by halophilic microorganisms inducing protective effects against various stressful factors. However, little is known about its influence on aquatic invertebrates subjected to hydrogen peroxide (H2O2)-a commonly used oxidative disinfectant. Therefore, the aim of our study was to determine the effects of H2O2 alone (at 5 and 10 mg/L) and in the combination with various concentrations of ECT (5, 10 and 25 mg/L) on behavioral, physiological and biochemical parameters of Daphnia magna. The following endpoints were determined: mortality, heart rate, thoracic limb movement, total glutathione (GSH)/oxidized glutathione (GSSG) ratio, catalase (CAT) activity and nitric oxide (NOx) level. The study showed that daphnids exposed to the combination of H2O2+ECT showed decreased mortality, attenuated inhibition of heart rate and thoracic limb activity, less decreased GSH/GSSG ratio, lower stimulation of CAT activity and NOx level when compared to the crustaceans exposed to H2O2 alone. The most pronounced alleviation of toxic effects was observed in the combination of 5 mg/L H2O2+25 mg/L ECT. The results suggest that protective effects of ECT in D. magna subjected to H2O2 may be related to antioxidative properties of the osmoprotectant.

  9. Coping with predator stress: interclonal differences in induction of heat-shock proteins in the water flea Daphnia magna.

    Science.gov (United States)

    Pauwels, K; Stoks, R; de Meester, L

    2005-07-01

    Although predation is a strong selection pressure, little is known about the molecular mechanisms to cope with predator stress. This is crucial to understanding of the mechanisms and constraints involved in the evolution of antipredator traits. We quantified the expression of heat-shock protein 60 (Hsp60), a potential marker for predator stress, in four clones of the water flea Daphnia magna, when exposed to fish kairomones. Expression of Hsp60 induction increased after 6 h and returned to base levels after 24 h of predator stress. This suggests that it is a costly transient mechanism to temporarily cope with novel predator stress, before other defences are induced. We found genetic variation in the fixed levels and in the fish-induced levels of Hsp60, which seemed to be linked to each clone's history of fish predation. Our data suggest that Hsp60 can be considered part of a multiple-trait antipredator defence strategy of Daphnia clones to cope with predator stress.

  10. Exploring embryonic germ line development in the water flea, Daphnia magna, by zinc-finger-containing VASA as a marker.

    Science.gov (United States)

    Sagawa, Kazunori; Yamagata, Hideo; Shiga, Yasuhiro

    2005-06-01

    VASA is an ATP-dependent RNA helicase belonging to the DEAD-box family that, in many organisms, is specifically expressed in germ line cells throughout the life cycle, making it a powerful molecular marker to study germ line development. To obtain further information on germ line development in crustaceans, we cloned VASA cDNAs from three branchiopod species: water fleas Daphnia magna and Moina macrocopa, and brine shrimp Artemia franciscana. RNA helicase domains in branchiopod VASA were highly conserved among arthropod classes. However, N-terminal RNA-binding domains in branchiopod VASA were highly diverged and, unlike other arthropod VASA reported so far, possessed repeats of retroviral-type zinc finger (CCHC) motifs. Raising specific antibodies against Daphnia VASA revealed that the primordial germ cells (PGCs) in this organism segregate at a very early cleavage stage of embryogenesis in parthenogenetic and sexual eggs. Clusters of PGCs then start to migrate inside the embryo and finally settle at both sides of the intestine, the site of future gonad development. RNA analyses suggested that maternally supplied vasa mRNA was responsible for early VASA expression, while zygotic expression started during blastodermal stage of development.

  11. Biological surface coating and molting inhibition as mechanisms of TiO2 nanoparticle toxicity in Daphnia magna.

    Directory of Open Access Journals (Sweden)

    André Dabrunz

    Full Text Available 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 (nTiO(2 led to toxicity in Daphnia magna at nominal concentrations of 3.8 (72-h EC(50 and 0.73 mg/L (96-h EC(50. However, nTiO(2 disappeared quickly from the ISO-medium water phase, resulting in toxicity levels as low as 0.24 mg/L (96-h EC(50 based on measured concentrations. Moreover, we showed that nTiO(2 (∼100 nm is significantly more toxic than non-nanosized TiO(2 (∼200 nm prepared from the same stock suspension. Most importantly, we hypothesized a mechanistic chain of events for nTiO(2 toxicity in D. magna that involves the coating of the organism surface with nTiO(2 combined with a molting disruption. Neonate D. magna (≤6 h exposed to 2 mg/L nTiO(2 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.

  12. Acute toxicity of oxygenated and nonoxygenated imidazolium-based ionic liquids to Daphnia magna and Vibrio fischeri.

    Science.gov (United States)

    Samorì, Chiara; Pasteris, Andrea; Galletti, Paola; Tagliavini, Emilio

    2007-11-01

    Room-temperature ionic liquids (RTILs) recently have generated great interest as a result of their potential commercial applications. In particular, because of their negligible vapor pressure and low inflammability, they have been suggested as green alternatives to traditional organic solvents. The toxicity and potential environmental risk of this heterogeneous class of chemicals, however, are poorly understood. An alkyl-substituted RTIL, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]), is one of the most widely used cations of RTILs, and information regarding its toxicity is relatively extensive. On the other hand, oxygenated chain-substituted ionic liquids, 1-methoxyethyl-3-methylimidazolium salts (moemims), are a new class of RTILs that have been poorly studied. Here, we compared the acute toxicity of [bmim][BF(4)] and moemims to the crustacean Daphnia magna (end point, 48-h immobilization) and the bacterium Vibrio fischeri (end point, 15-min inhibition of bioluminescence). The concentrations of [bmim][BF(4)] resulting in 50% of the maximum adverse effect (EC50s) for D. magna and V. fischeri were 5.18 and 300 mg/L, respectively, and were consistent with previously published values. The EC50s of the two moemims for D. magna are very similar, ranging from 209 to 222 mg/L in different experimental trials, and are higher by two orders of magnitude than the EC50 of [bmim][BF(4)]. The EC50s of 1-methoxyethyl-3-methylimidazolium tetrafluoroborate ([moemim][BF(4)]) and 1-methoxyethyl-3-methylimidazolium dicyanamide ([moemim][dca]) for V. fischeri are 3,196 and 2,406 mg/L, respectively. Results indicate that introduction of an oxygenated side chain in the imidazolium cation can greatly reduce the toxicity of RTILs and that these RTILs are less toxic than commonly used chlorinated solvents, such as tricloromethane, but are more toxic than nonchlorinated solvent, such as methanol and acetone.

  13. Acute and chronic toxicity of four frequently used UV filter substances for Desmodesmus subspicatus and Daphnia magna.

    Science.gov (United States)

    Sieratowicz, Agnes; Kaiser, Dominic; Behr, Maximilian; Oetken, Matthias; Oehlmann, Jörg

    2011-01-01

    As a consequence of growing public concern about UV radiation effects on human health chemical and physical UV filters are increasingly used in personal care and other products. The release of these lipophilic and often persistent compounds into surface waters may pose a risk for aquatic organisms. The aim of the study was to determine effects of four frequently used UV filters on primary aquatic producers and consumers, the green alga Desmodesmus subspicatus and the crustacean Daphnia magna. Exposure to benzophenone 3 (BP3), ethylhexyl methoxycinnamate (EHMC), 3-benzylidene camphor (3-BC) and 3-(4'-methylbenzylidene)-camphor (4-MBC) resulted in growth inhibition of D. subspicatus with 72 h IC(10) values of 0.56 mg/L (BP 3), 0.24 mg/L (EHMC), 0.27 mg/L (3-BC) and 0.21 mg/L (4-MBC). EC(50) concentrations in the acute test with D. magna were 1.67, 0.57, 3.61 and 0.80 mg/L for BP3, EHMC, 3-BC and 4-MBC, respectively. Chronic exposure of D. magna resulted in NOECs of 0.04 mg/L (EHMC) and 0.1 mg/L (3-BC and 4-MBC). BP 3 showed no effects on neonate production or the length of adults. Rapid dissipation of these substances from the water phase was observed indicating the need for more frequent test medium renewal in chronic tests or the use of flow-through test systems.

  14. To flee or not to flee: detection, avoidance and attraction of profitable resources by Daphnia magna studied with olfactometer

    Directory of Open Access Journals (Sweden)

    Johann P. Müller

    2013-10-01

    Full Text Available The cladoceran herbivore Daphnia magna is a major consumer of phytoplankton in lakes. Therefore, this organism may control the phytoplankton community and the proliferation of some algae or cyanobacteria. Cladoceran behaviour and migration in relation to temperature, light or presence of planktivorous fishes have been well studied. In particular, it is known that the detection of kairomones produced by predators may induce avoidance. Avoidance could also occur with other semiochemicals such as cyanotoxins. In order to explore this hypothesis, we used an olfactometer to observe and measure the exploratory behaviour of D. magna individuals based on the motivation for food. Daphnids were allowed to choose between different compounds: water, a pure cyanotoxin, i.e. the microcystin-RR [(MC-RR], extracts of one MC-producing strain (PMC 75.02 and one MC-free strain (PMC 87.02 of Planktothrix agardhii, or a green algae Scenedesmus obliquus. With this experimental design, we observed that i cladocerans are able to detect resources with different qualities, ii they can explore before exhibiting preferences, and iii daphnids are able to avoid compounds that are potentially toxic (e.g., microcystins. First, daphnids explored the environment, subsequently (after about 1.5 h, they showed a significant tendency to stay where there is a profitable resource such as S. obliquus. These results also suggest that specimens of D. magna cannot detect MC compounds from P. agardhii, but they respond to it as a food resource. The study of zooplankton ability to explore the environment when exposed to semiochemicals needs further investigation. 

  15. Development of a new biomonitoring method to detect the abnormal activity of Daphnia magna using automated Grid Counter device.

    Science.gov (United States)

    Jeon, Junho; Kim, Joon Ha; Lee, Byung Cheun; Kim, Sang Don

    2008-01-25

    The aim of the present study was to develop a biological early warning system (BEWS), equipped with six monitoring channels to individually observe the activity of Daphnia magna, using a digital 'Grid Counter', which would trigger an alarm within an appropriate time, and examine the functional performance of the newly developed BEWS for detecting unusual water quality. In order to detect the changes in the activity of D. magna, six relative activity parameter values (Z(a)) were computed from the 6 individual monitoring channels; with the activity data for D. magna calculated every 5 min. The Student's t-test was used to verify the difference between the mean value of the system in a steady state, as a control, and the exposure values during a sudden pollution event. The test results illustrate that the threshold value for the alarm can be at p=0.0093 for 3 consecutive detections. The time period, defined as the average time taken from the detection of hyper to retarded activity of the organism, for Cu concentrations of 50, 100, 200 and 400 ppb were 7.17+/-1.75, 3.94+/-2.02, 1.85+/-0.49 and 1.00+/-0.18 h, respectively. Based on the results of this study, it is proposed that p values from the t-test, with Z(a), are more accurate, stable and predictable parameters for the detection of chemical exposures than the other values, such as the swimming speed and trajectory, etc. Consequently, it would be possible to reduce the number of false alarms and achieve confidence for a system, with the ability of highly accurate detection, such as with the six-channel monitoring system developed in this study.

  16. Altered quantities and in vivo activities of cholinesterase from Daphnia magna in sub-lethal exposure to organophosphorus insecticides.

    Science.gov (United States)

    Liu, Hongcui; Yuan, Bingqiang; Li, Shaonan

    2012-06-01

    For investigating relationship between activity of cholinesterase (ChE) and ambient concentration of anticholinesterases, Daphnia magna had been exposed for 21 day to sub-lethal concentrations, i.e. 1/6 EC(50), 1/36 EC(50), and 1/216 EC(50), of either triazophos or chlorpyrifos. Samples were taken at different points of time for measuring total activity and immunoreactive content of ChE and actual concentrations of the anticholinesterases. A type of antigen formerly developed by immunizing mice with purified ChE was utilized in this study to establish an indirect non-competitive ELISA for measuring immunoreactive content of ChE in Daphnia. Studies showed that for apparent activity, i.e. activity that was scaled with total protein, the insecticides caused 5.2-6.9 percent inhibition and 17.0-17.7 percent inductions during the 21 d exposure, whereas for inherent activity, i.e. activity that was scaled with immunoreactive protein, no induction was detected during the exposure. Accompanied by up to 65.9 percent and 68.0 percent promotion in terms of the immunoreactive content, up to 42.8 percent and 44.6 percent inhibition in terms of the inherent activity was indicated, respectively, for triazophos and chlopyrifos. Judged by measured concentrations, the inherent activity recovered faster than the rate of dissipation of the anticholinesterases. Result of the study suggested that the inherent activity was more sensitive than the apparent one in predicting sub-lethal and/or long-term stress of anticholinesterases. It also suggested that apart from promotion in terms of content of the ChE, the Daphnia developed capacities to block bio-concentration of anticholinesterases, and these capacities would make it liable to underestimate ambient concentration of anticholinesterases along with the time of exposure.

  17. Toxic effects of Pseudanabaena tenuis (Cyanobacteria on the cladocerans Daphnia magna and Ceriodaphnia dubia Efectos tóxicos de Pseudanabaena tenuis (Cyanobacteria en los cladóceros Daphnia magna y Ceriodaphnia dubia

    Directory of Open Access Journals (Sweden)

    Roxana Olvera-Ramírez

    2010-01-01

    Full Text Available Some cyanobacteria can produce toxins that affect the aquatic biota and represent a human health risk. The cyanobacterium Pseudanabaena tenuis was isolated from the Valle de Bravo dam, and cultured in the laboratory under controlled conditions. We determined the acute toxic effects and performed a chronic (consumption test in the cladocerans Daphnia magna (a reference test organism and Ceriodaphnia dubia (a cosmopolitan species. To determine acute toxicity, three exposure ways were assayed: a cell-free culture medium, b crude cell extracts of the cyanobacterium after lysing, and c aqueous extracts of P. tenuis phycobiliproteins. On the other hand, both cladocerans were fed P. tenuis, assessing the effects on survival and reproduction. For comparison, a control culture of both cladocerans was fed the green microalga Pseudokirchneriella subcapitata. Exposure to the cell-free culture medium did not produce any mortality in either cladoceran, but the aqueous and crude extracts generated acute toxicity. D. magna and C. dubia were negatively affected when fed P. tenuis, since their survival, total progeny, average number of neonates per clutch, and the number of clutches decreased. C. dubia was more sensitive than D. magna, both in the acute toxicity tests and to the effects of P. tenuis consumption. Although most of the blooms around the world are dominated by cyanobacteria of the genus Microcystis, attention should be given to other species, such as P. tenuis, because, frequently, it is not recognized that smaller cyanobacteria could exceed the larger species in terms of biomass, and produce noxious biological effects.Algunas cianobacterias producen toxinas que afectan la biota acuática y representan un riesgo para la salud humana. La cianobacteria Pseudanabaena tenuis fue aislada del embalse Valle de Bravo y cultivada en el laboratorio. Se determinaron los efectos tóxicos agudos (por exposición y se evaluó la toxicidad crónica (por consumo

  18. Neurogenesis in the water flea Daphnia magna (Crustacea, Branchiopoda) suggests different mechanisms of neuroblast formation in insects and crustaceans.

    Science.gov (United States)

    Ungerer, Petra; Eriksson, Bo Joakim; Stollewerk, Angelika

    2011-09-01

    Within euarthropods, the morphological and molecular mechanisms of early nervous system development have been analysed in insects and several representatives of chelicerates and myriapods, while data on crustaceans are fragmentary. Neural stem cells (neuroblasts) generate the nervous system in insects and in higher crustaceans (malacostracans); in the remaining euarthropod groups, the chelicerates (e.g. spiders) and myriapods (e.g. millipedes), neuroblasts are missing. In the latter taxa, groups of neural precursors segregate from the neuroectoderm and directly differentiate into neurons and glial cells. In all euarthropod groups, achaete-scute homologues are required for neuroblast/neural precursor group formation. In the insects Drosophila melanogaster and Tribolium castaneum achaete-scute homologues are initially expressed in clusters of cells (proneural clusters) in the neuroepithelium but expression becomes restricted to the future neuroblast. Subsequently genes such as snail and prospero are expressed in the neuroblasts which are required for asymmetric division and differentiation. In contrast to insects, malacostracan neuroblasts do not segregate into the embryo but remain in the outer neuroepithelium, similar to vertebrate neural stem cells. It has been suggested that neuroblasts are present in another crustacean group, the branchiopods, and that they also remain in the neuroepithelium. This raises the questions how the molecular mechanisms of neuroblast selection have been modified during crustacean and insect evolution and if the segregation or the maintenance of neuroblasts in the neuroepithelium represents the ancestral state. Here we take advantage of the recently published Daphnia pulex (branchiopod) genome and identify genes in Daphnia magna that are known to be required for the selection and asymmetric division of neuroblasts in the fruit fly D. melanogaster. We unambiguously identify neuroblasts in D. magna by molecular marker gene expression and

  19. The influence of natural organic matter and aging on suspension stability in guideline toxicity testing of silver, zinc oxide, and titanium dioxide nanoparticles with Daphnia magna

    DEFF Research Database (Denmark)

    Cupi, Denisa; Hartmann, Nanna Isabella Bloch; Baun, Anders

    2015-01-01

    The present study investigated changes in suspension stability and ecotoxicity of engineered nanoparticles (ENPs) by addition of Suwannee River natural organic matter and aging of stock and test suspensions prior to testing. Acute toxicity tests of silver (Ag), zinc oxide (ZnO), and titanium...... dioxide (TiO2) ENPs with Daphnia magna were carried out following Organisation for Economic Co-operation and Development test guidelines. Daphnia magna was found to be very sensitive to Ag ENPs (48-h 50% effective concentration 33μgL-1), and aging of the test suspensions in M7 medium (up to 48h) did...... not decrease toxicity significantly. Conversely, the presence of Suwannee River natural organic matter (NOM; 20mgL-1) completely alleviated Ag ENP toxicity in all testing scenarios and did not aid in stabilizing suspensions. In contrast, addition of Suwannee River NOM stabilized ZnO ENP suspensions and did...

  20. The potential of TiO{sub 2} nanoparticles as carriers for cadmium uptake in Lumbriculus variegatus and Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Nanna B., E-mail: Nanna.Hartmann@ec.europa.eu [Department of Environmental Engineering, Technical University of Denmark, Building 113, Kgs. Lyngby (Denmark); Legros, Samuel; Von der Kammer, Frank; Hofmann, Thilo [Department of Environmental Geosciences, University of Vienna, Althanstrasse 14, A-1090 Vienna (Austria); Baun, Anders [Department of Environmental Engineering, Technical University of Denmark, Building 113, Kgs. Lyngby (Denmark)

    2012-08-15

    The use of engineered nanoparticles (e.g. in industrial applications and consumer products) is increasing. Consequently, these particles will be released into the aquatic environment. Through aggregation/agglomeration and sedimentation, sediments are expected ultimately to be sinks for nanoparticles. Both in the water phase and in the sediments engineered nanoparticles will mix and interact with other environmental pollutants, including metals. In this study the toxicity of cadmium to two freshwater organisms, water column crustacean Daphnia magna and sediment oligochaete Lumbriculus variegatus, was investigated both in the absence and presence of titanium dioxide (TiO{sub 2}) nanoparticles (P25 Evonic Degussa, d: 30 nm). The uptake of cadmium in sub-lethal concentrations was also studied in the absence and presence of 2 mg/L TiO{sub 2} nanoparticles. Formation of larger nanoparticles aggregates/agglomerates was observed and sizes varied depending on media composition (358 {+-} 13 nm in US EPA moderately hard synthetic freshwater and 1218 {+-} 7 nm in Elendt M7). TiO{sub 2} nanoparticles are potential carriers for cadmium and it was found that 25% and 6% of the total cadmium mass in the test system for L. variegatus and D. magna tests were associated to suspended TiO{sub 2} particles, respectively. {mu}XRF (micro X-ray fluorescence) analysis confirmed the uptake of TiO{sub 2} in the gut of D. magna. For L. variegatus {mu}XRF analysis indicated attachment of TiO{sub 2} nanoparticles to the organism surface as well as a discrete distribution within the organisms. Though exact localisation in this organism was more difficult to assess, the uptake seems to be within the coelomic cavity. Results show that the overall body burden and toxicity of cadmium to L. variegatus was unchanged by addition of TiO{sub 2} nanoparticles, showing that cadmium adsorption to TiO{sub 2} nanoparticles did not affect overall bioavailability. Despite facilitated uptake of cadmium by Ti

  1. Influence of environmental factors on the response of a natural population of Daphnia magna (Crustacea: Cladocera) to spinosad and Bacillus thuringiensis israelensis in Mediterranean coastal wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Duchet, C. [Entente Interdepartementale de Demoustication du Littoral Mediterraneen, 165 avenue Paul-Rimbaud, Montpellier F-34184 (France); INRA, UMR985 Ecologie et Sante des Ecosystemes, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint Brieuc, Rennes F-35042 (France); Caquet, Th. [INRA, UMR985 Ecologie et Sante des Ecosystemes, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint Brieuc, Rennes F-35042 (France); Franquet, E. [Universite Paul Cezanne, Institut Mediterraneen d' Ecologie et de Paleoecologie, Faculte des Sciences et Techniques Saint Jerome, C31, Marseille F-13397 (France); Lagneau, C. [Entente Interdepartementale de Demoustication du Littoral Mediterraneen, 165 avenue Paul-Rimbaud, Montpellier F-34184 (France); Lagadic, L., E-mail: Laurent.Lagadic@rennes.inra.f [INRA, UMR985 Ecologie et Sante des Ecosystemes, Equipe Ecotoxicologie et Qualite des Milieux Aquatiques, 65 rue de Saint Brieuc, Rennes F-35042 (France)

    2010-05-15

    The present study was undertaken to assess the impact of a candidate mosquito larvicide, spinosad (8, 17 and 33 mug L{sup -1}) on a field population of Daphnia magna under natural variations of water temperature and salinity, using Bti (0.16 and 0.50 muL L{sup -1}) as the reference larvicide. Microcosms (125 L) were placed in a shallow temporary marsh where D. magna was naturally present. The peak of salinity observed during the 21-day observation period may have been partly responsible for the decrease of daphnid population density in all the microcosms. It is also probably responsible for the absence of recovery in the microcosms treated with spinosad which caused a sharp decrease of D. magna abundance within the first two days following treatment whereas Bti had no effect. These results suggest that it may be difficult for a field population of daphnids to cope simultaneously with natural (water salinity and temperature) and anthropogenic (larvicides) stressors. - Significant interaction between salinity and spinosad exposure impairs the recovery of a natural population of Daphnia magna.

  2. Evaluation of Daphnia Magna Neonate Viability under Low Temperature Exposure Conditions

    Science.gov (United States)

    2007-01-25

    of the United States Protozoa to Mollusca , 3rd ed. John Wiley & Sons, Inc., New York, NY. Pijanowska, J. and G. Stolpe. 1996. Summer Diapause...and Receiving Waters to Freshwater and Marine Organisms, Appendix A.2 (D. magna and D. pulex) Distribution, Life Cycle, Taxonomy , and Culture Methods

  3. Influences of the coating on silver nanoparticle toxicity in a chronic test with Daphnia magna

    DEFF Research Database (Denmark)

    Sakka, Y.; Mackevica, Aiga; Skjolding, Lars Michael

    2015-01-01

    coated AgNP in a chronic Daphnia test. One type of AgNP was coated with citrate (cAgNP), the other AgNP were generally uncoated (pAgNP; p= pure), but sterically stabilized by an organic dispersant. Particles with a similar shape and diameter were chosen. The focus of the study was to relate observed...

  4. Differential levels of stress proteins (HSPs) in male and female Daphnia magna in response to thermal stress: a consequence of sex-related behavioral differences?

    Science.gov (United States)

    Mikulski, Andrzej; Bernatowicz, Piotr; Grzesiuk, Małgorzata; Kloc, Małgorzata; Pijanowska, Joanna

    2011-07-01

    In two independent experiments, we compared: (1) water depth selection (and accompanying temperature selection) by male and female Daphnia magna under different kinds of environmental stress, including the presence of filamentous cyanobacteria, the risk of predation from fish, and the presence of toxic compounds; and (2) sex-dependent production of heat shock proteins (HSP60, 70, and 90) in response to a sudden change in temperature. Male D. magna selected deep water strata, which offer a relatively stable environment, and thereby avoided the threat of predation and the presence of toxic compounds in surface waters. Correlated with this behavior, males reduce their molecular defenses against stress, such as the production of heat shock proteins (HSPs), and do not maintain the physiological machinery that triggers an increase in HSP levels in response to stress. In contrast, female D. magna actively select habitats that offer optimal conditions for growth and production of offspring. Consequently, females are exposed to variable environmental conditions that may be associated with increased stress. To permit survival in these different habitats, D. magna females require molecular mechanisms to protect their cells from rapid changes in stress levels. Thus, they maintain high constitutive levels of the heat shock proteins from HSP 60, 70, and 90 families, and they have the potential to further enhance the production of the majority of these proteins under stress conditions. The results of this study indicate that the separate habitats selected by male and female D. magna result in different patterns of HSP production, leading us to hypothesize that that male and female Daphnia magna adopt different strategies to maximize the fitness of the species.

  5. Sediment Zn-release during post-drought re-flooding: Assessing environmental risk to Hyalella azteca and Daphnia magna.

    Science.gov (United States)

    Nedrich, Sara M; Burton, G Allen

    2017-11-01

    Hydrologic variability exacerbated by climate change affects biogeochemical cycling in sediments through changes in pH, redox, and microbial activity. These alterations affect the lability and speciation of metals, such that toxicity may be observed in otherwise non-toxic sediments. In this study, we investigate the effects of drought and reflooding on metal bioavailability in sediments with low to moderate concentrations of Zn (18-270 mg kg(-1)). Sediments were collected from coastal wetlands in Michigan, dried (36-days) and re-inundated in lab microcosms. We investigated the relationships between key parameters, for surface/porewater (dissolved and particulate metals, dissolved oxygen, redox (Eh), reduced iron, and temperature) and sediment (simultaneously extracted metals (SEM), acid volatile sulfide (AVS), Fe/Mn-oxyhydroxide, organic carbon, water content analyses, and diffusive gradient in thin films (DGTs) metal concentrations). Porewater Zn increased with inundation of dried sediments for all sediment types, exceeding United States Environmental Protection Agency (U.S. EPA) chronic criteria for freshwater organisms, and decreased as sediments became reduced. Effects on Hyalella azteca (7-day exposure) and Daphnia magna (10-day exposure) were quantified. Results show decreased growth of H. azteca for sites with elevated Zn and increased Zn-body concentration (BCZn) in the most contaminated sediment type. Further, BCZn was negatively correlated with H. azteca growth. D. magna survival, growth, and reproduction were not affected. DGT metal concentrations were more reflective of porewater than organism bioaccumulation. Outcomes of predictive toxicology methods are compared to toxicity test results and suggestions are provided for model improvements. This study demonstrates that post-drought re-flooding of sediments affects Zn biogeochemical cycling with potentially adverse effects on benthic organisms, even in sediments with only moderately elevated

  6. Uncovering ultrastructural defences in Daphnia magna--an interdisciplinary approach to assess the predator-induced fortification of the carapace.

    Directory of Open Access Journals (Sweden)

    Max Rabus

    Full Text Available The development of structural defences, such as the fortification of shells or exoskeletons, is a widespread strategy to reduce predator attack efficiency. In unpredictable environments these defences may be more pronounced in the presence of a predator. The cladoceran Daphnia magna (Crustacea: Branchiopoda: Cladocera has been shown to develop a bulky morphotype as an effective inducible morphological defence against the predatory tadpole shrimp Triops cancriformis (Crustacea: Branchiopoda: Notostraca. Mediated by kairomones, the daphnids express an increased body length, width and an elongated tail spine. Here we examined whether these large scale morphological defences are accompanied by additional ultrastructural defences, i.e. a fortification of the exoskeleton. We employed atomic force microscopy (AFM based nanoindentation experiments to assess the cuticle hardness along with tapping mode AFM imaging to visualise the surface morphology for predator exposed and non-predator exposed daphnids. We used semi-thin sections of the carapace to measure the cuticle thickness, and finally, we used fluorescence microscopy to analyse the diameter of the pillars connecting the two carapace layers. We found that D. magna indeed expresses ultrastructural defences against Triops predation. The cuticle in predator exposed individuals is approximately five times harder and two times thicker than in control daphnids. Moreover, the pillar diameter is significantly increased in predator exposed daphnids. These predator-cue induced changes in the carapace architecture should provide effective protection against being crushed by the predator's mouthparts and may add to the protective effect of bulkiness. This study highlights the potential of interdisciplinary studies to uncover new and relevant aspects even in extensively studied fields of research.

  7. Priority and emerging flame retardants in rivers: occurrence in water and sediment, Daphnia magna toxicity and risk assessment.

    Science.gov (United States)

    Cristale, Joyce; García Vázquez, Alejandro; Barata, Carlos; Lacorte, Silvia

    2013-09-01

    The occurrence, partitioning and risk of eight polybrominated diphenyl ethers (PBDEs), nine new brominated (NBFRs) and ten organophosphorus flame retardants (OPFRs) were evaluated in three Spanish rivers suffering different anthropogenic pressures (Nalón, Arga and Besòs). OPFRs were ubiquitous contaminants in water (ΣOPFRs ranging from 0.0076 to 7.2μgL(-1)) and sediments (ΣOPFRs ranging 3.8 to 824μgkg(-1)). Brominated flame retardants were not detected in waters, whereas ΣPBDEs ranged from 88 to 812μgkg(-1) and decabromodiphenyl ethane (DBDPE) reached 435μgkg(-1) in sediments from the River Besòs, the most impacted river. The occurrence of flame retardants in river water and sediment was clearly associated with human activities, since the highest levels occurred near urban and industrial zones and after wastewater treatment plants discharge. Daphnia magna toxicity was carried out for OPFRs, the most ubiquitous flame retardants, considering individual compounds and mixtures. Toxicity of nine tested OPFRs differed largely among compounds, with EC50 values ranging over three magnitude orders (0.31-381mgL(-1)). Results evidenced that these compounds act by non-polar narcosis, since their toxicity was proportional to their lipophilicity (Kow). Furthermore, their joint toxicity was additive, which means that single and joint toxicity can be predicted knowing their concentration levels in water using quantitative structure activity relationships (QSARs) and predictive mixture models. Based on these results, a risk assessment considering joint effect was performed calculating and summing risk quotients (RQs) for the water and sediment samples. No significant risk to D. magna (ΣRQs <1) was observed for any of the monitored rivers.

  8. Chronic toxicity of five structurally diverse demethylase-inhibiting fungicides to the crustacean Daphnia magna: a comparative assessment.

    Science.gov (United States)

    Hassold, Enken; Backhaus, Thomas

    2009-06-01

    Demethylase inhibitors (DMIs) are broad-spectrum fungicides that are ubiquitously used in agriculture and medicine. They comprise chemically heterogeneous substances that share a common biochemical target in fungi, the inhibition of a specific step in sterol biosynthesis. Several DMIs are suspected to disrupt endocrine-mediated processes in a range of organisms and to inhibit ecdysteroid biosynthesis in arthropods. It is unclear, however, whether and, if so, to what extent different DMI fungicides have a similar mode of action in nontarget organisms, which in turn would lead to a common chronic toxicity profile. Therefore, we selected a representative of each of the major DMI classes--the piperazine triforine, the pyrimidine fenarimol, the pyridine pyrifenox, the imidazole prochloraz, and the triazole triadimefon--and comparatively investigated their chronic toxicity to Daphnia magna. No toxicity was detectable up to the limit of solubility of triforine (61 micromol/L). All other DMIs reduced reproductive success by delaying molting and development and by causing severe developmental abnormalities among offspring. Prochloraz was most toxic (median effective concentration [EC50] for fecundity reduction, 0.76 micromol/L), followed by fenarimol (EC50, 1.14 micromol/L), pyrifenox (EC50, 3.15 micromol/L), and triadimefon (EC50, 5.13 micromol/L). Mean effect concentrations for fecundity reduction were related to lipophilicity and followed baseline toxicity. However, triadimefon and fenarimol (but none of the other tested DMIs) caused severe eye malformations among exposed offspring. Affected neonates did survive, but a reduced ecological fitness can be assumed. Offspring exposed to fenarimol in mater matured earlier. The investigated different life-history parameters were affected in a substance-specific manner. These qualitatively different toxicity profiles suggest additional, substance-specific mechanisms of action in D. magna that probably are related to an

  9. Impact of dispersant on early life stages of the water flea Daphnia magna and the eastern oyster Crassostrea virginica.

    Science.gov (United States)

    Salehi, Maryam; Rodriguez, Rachel; Boettcher, Anne; Powers, Sean; Geitner, Nick; Ladner, David A; Rikard, Scott; Whelton, Andrew J

    2017-06-27

    In response to the 2010 Deepwater Horizon oil spill, over 1 million gallons of dispersant were applied in Gulf of Mexico offshore waters; Corexit 9500 was the most applied dispersant. The impact on organisms in nearshore and freshwaters has received little scrutiny. Acute 48 h toxicity of Corexit 9500 and a new hyperbranched polyethylenimine (HPEI) dispersant-like compound were evaluated for the freshwater indicator organism, Daphnia magna and for larval and early spat stages of the Eastern oyster, Crassostrea virginica. For D. magna, Corexit 9500 demonstrated toxicity (EC50 of 0.14 [0.13, 0.15] ppm) similar to the 10-kDa HPEI (EC50 of 0.16 [0.12, 0.19] ppm). HPEI toxicity increased as a function of molecular weight (1.2 to 750 kDa). The 10 kDa size HPEI was further investigated because it dispersed crude oil with equal effectiveness as Corexit. For Corexit, 100% oyster mortality was detected for the ≤0.2-mm size classes and mortality >50% for the 0.3- and 0.7-mm size classes at the two greatest concentrations (25 and 50 ppm). HPEI (10 kDa) exhibited low mortality rates (<30%) for all concentrations for all oyster size classes except the 0.1-mm class. Although mortality rates for this size class were up to 60%, mortality was still less than the mortality caused by Corexit 9500. The low toxicity of HPEI polymers for C. virginica in comparison with Corexit 9500 suggests that HPEI polymers warrant further study. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Comparing humic substance and protein compound effects on the bioaccumulation of perfluoroalkyl substances by Daphnia magna in water.

    Science.gov (United States)

    Xia, Xinghui; Dai, Zhineng; Rabearisoa, Andry Harinaina; Zhao, Pujun; Jiang, Xiaoman

    2015-01-01

    The influence of humic substances and protein compounds on the bioaccumulation of six types of perfluoroalkyl substances (PFASs) in Daphnia magna was compared. The humic substances included humic acid (HA) and fulvic acid (FA), the protein compounds included chicken egg albumin (albumin) and peptone, and the PFASs included perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Four concentrations (0, 1, 10, and 20 mg L(-1)) of the four dissolved organic matter (DOM) types were investigated. At the 1 mg L(-1) level, HA and albumin enhanced all tested PFAS bioaccumulation, whereas FA and peptone only enhanced the bioaccumulation of shorter-chain PFASs (PFOS, PFOA, and PFNA). However, all four DOM types decreased all tested PFAS bioaccumulation at the 20 mg L(-1) level, and the decreasing ratios of bioaccumulation factors caused by FA, HA, albumin, and peptone were 1-49%, 23-77%, 17-58%, and 8-56%, respectively compared with those without DOM. This is because DOM not only reduced the bioavailable concentrations and uptake rates of PFASs but also lowered the elimination rates of PFASs in D. magna, and these opposite effects would change with different DOM types and concentrations. Although the partition coefficients (L kg(-1)) of PFASs between HA and water (10(4.21)-10(4.98)) were much lower than those between albumin and water (10(4.92)-10(5.86)), their effects on PFAS bioaccumulation were comparable. This study suggests that although PFASs are a type of proteinophilic compounds, humic substances also have important effects on their bioavailability and bioaccumulation in aquatic organisms.

  11. Uncovering ultrastructural defences in Daphnia magna--an interdisciplinary approach to assess the predator-induced fortification of the carapace.

    Science.gov (United States)

    Rabus, Max; Söllradl, Thomas; Clausen-Schaumann, Hauke; Laforsch, Christian

    2013-01-01

    The development of structural defences, such as the fortification of shells or exoskeletons, is a widespread strategy to reduce predator attack efficiency. In unpredictable environments these defences may be more pronounced in the presence of a predator. The cladoceran Daphnia magna (Crustacea: Branchiopoda: Cladocera) has been shown to develop a bulky morphotype as an effective inducible morphological defence against the predatory tadpole shrimp Triops cancriformis (Crustacea: Branchiopoda: Notostraca). Mediated by kairomones, the daphnids express an increased body length, width and an elongated tail spine. Here we examined whether these large scale morphological defences are accompanied by additional ultrastructural defences, i.e. a fortification of the exoskeleton. We employed atomic force microscopy (AFM) based nanoindentation experiments to assess the cuticle hardness along with tapping mode AFM imaging to visualise the surface morphology for predator exposed and non-predator exposed daphnids. We used semi-thin sections of the carapace to measure the cuticle thickness, and finally, we used fluorescence microscopy to analyse the diameter of the pillars connecting the two carapace layers. We found that D. magna indeed expresses ultrastructural defences against Triops predation. The cuticle in predator exposed individuals is approximately five times harder and two times thicker than in control daphnids. Moreover, the pillar diameter is significantly increased in predator exposed daphnids. These predator-cue induced changes in the carapace architecture should provide effective protection against being crushed by the predator's mouthparts and may add to the protective effect of bulkiness. This study highlights the potential of interdisciplinary studies to uncover new and relevant aspects even in extensively studied fields of research.

  12. Morphological evidence of mechanoreceptive gravity perception in a water flea - Daphnia magna

    Science.gov (United States)

    Meyers, D. G.

    1985-01-01

    Hair-like structures or setae located in the basal membrane of the swimming antennae of the water flea, D. magna, were observed by scanning electron microscopy and compared to mechanoreceptors in the Higher Order Crustacea. Similarities in anatomy, size, attachment, number, length, and orientation support the hypothesis that the setae are rheoceptive mechanoreceptors which mediate gravity perception through deflection by water currents during the sink phase of hop-and-sink swimming behavior.

  13. A Bayesian model for the identification of differentially expressed genes in Daphnia magna exposed to munition pollutants.

    Science.gov (United States)

    Cassese, Alberto; Guindani, Michele; Antczak, Philipp; Falciani, Francesco; Vannucci, Marina

    2015-09-01

    In this article we propose a Bayesian hierarchical model for the identification of differentially expressed genes in Daphnia magna organisms exposed to chemical compounds, specifically munition pollutants in water. The model we propose constitutes one of the very first attempts at a rigorous modeling of the biological effects of water purification. We have data acquired from a purification system that comprises four consecutive purification stages, which we refer to as "ponds," of progressively more contaminated water. We model the expected expression of a gene in a pond as the sum of the mean of the same gene in the previous pond plus a gene-pond specific difference. We incorporate a variable selection mechanism for the identification of the differential expressions, with a prior distribution on the probability of a change that accounts for the available information on the concentration of chemical compounds present in the water. We carry out posterior inference via MCMC stochastic search techniques. In the application, we reduce the complexity of the data by grouping genes according to their functional characteristics, based on the KEGG pathway database. This also increases the biological interpretability of the results. Our model successfully identifies a number of pathways that show differential expression between consecutive purification stages. We also find that changes in the transcriptional response are more strongly associated to the presence of certain compounds, with the remaining contributing to a lesser extent. We discuss the sensitivity of these results to the model parameters that measure the influence of the prior information on the posterior inference.

  14. Molecular responses during cadmium-induced stress in Daphnia magna: Integration of differential gene expression with higher-level effects

    Energy Technology Data Exchange (ETDEWEB)

    Soetaert, Anneleen [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)]. E-mail: anneleen.soetaert@ua.ac.be; Vandenbrouck, Tine [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Ven, Karlijn van der [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Maras, Marleen [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Remortel, Piet van [Department of Mathematics and Informatics, Intelligent Systems Laboratory, University of Antwerp, Middelheimlaan 1, B-2020 Antwerp (Belgium); Blust, Ronny [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Coen, Wim M. de [Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2007-07-20

    DNA microarrays offer great potential in revealing insight into mechanistic toxicity of contaminants. The aim of the present study was (i) to gain insight in concentration- and time-dependent cadmium-induced molecular responses by using a customized Daphnia magna microarray, and (ii) to compare the gene expression profiles with effects at higher levels of biological organization (e.g. total energy budget and growth). Daphnids were exposed to three cadmium concentrations (nominal value of 10, 50, 100 {mu}g/l) for two time intervals (48 and 96 h). In general, dynamic expression patterns were obtained with a clear increase of gene expression changes at higher concentrations and longer exposure duration. Microarray analysis revealed cadmium affected molecular pathways associated with processes such as digestion, oxygen transport, cuticula metabolism and embryo development. These effects were compared with higher-level effects (energy budgets and growth). For instance, next to reduced energy budgets due to a decline in lipid, carbohydrate and protein content, we found an up-regulated expression of genes related to digestive processes (e.g. {alpha}-esterase, cellulase, {alpha}-amylase). Furthermore, cadmium affected the expression of genes coding for proteins involved in molecular pathways associated with immune response, stress response, cell adhesion, visual perception and signal transduction in the present study.

  15. Study on the toxicity of sodium bromide to different fresh water organisms. [Scenedesmus pannonicus; Daphnia magna; Poecilia reticulata; Oryzias latipas

    Energy Technology Data Exchange (ETDEWEB)

    Canton, J.H.; Wester, P.W.; Mathijssen-Spiekman, E.A.

    1983-08-01

    The toxicity of sodium bromide for fresh water organisms was tested using algae (Scenedesmus pannonicus), crustaceans (Daphnia magna) and fish (Poecilia reticulata and Oryzias latipes). Depending on the species tested, the acute toxicity varied from 44 to 5800 mg Br-/litre (EC50 values) and the No Observed Effect Concentrations (NOEC values) in the long-term tests varied from 7.8 to 250 mg Br-/litre. Bromide ion markedly impaired reproduction in both crustaceans and fish. Histologically no effects were observed in the long-term test with Oryzias, but in the reproduction test with Poecilia, hyperplasia of the thyroid, atrophy and degeneration of the musculature and regressive changes in the female reproductive tract were observed. As a criterion of water quality, 1 mg Br-/litre has been proposed, on the basis of reproductive performance in the Poecilia test. The concentrations found in surface water frequently exceed this value and sometimes reach levels at which acute effects on water organisms can be expected.

  16. Read-Across Prediction of the Acute Toxicity of Organic Compounds toward the Water Flea Daphnia magna.

    Science.gov (United States)

    Kühne, Ralph; Ebert, Ralf-Uwe; von der Ohe, Peter C; Ulrich, Nadin; Brack, Werner; Schüürmann, Gerrit

    2013-01-01

    According to the European REACH Directive, the acute daphnid toxicity needs to be assessed for industrial chemicals with market volumes ≥1 t/a. Employing a data set of 1365 organic compounds with experimental 48-h LC50 data for Daphnia magna, a read-across approach has been developed that makes use of the atom-centered fragment (ACF) method as quantitative measure for structural similarity. Both quantitative log LC50 predictions and a discrimination between narcosis-level and excess toxicity can be obtained, augmented by similarity-triggered information that characterizes a compound as inside or outside the quantitative or qualitative model domain. Reading across proceeds as interpolation of the toxicity enhancement (Te ) over predicted narcosis-level toxicity, taking experimental log Te values from similarity-selected reference compounds as input. The resultant decision tree model yields r(2) =0.85 and rms=0.66 for the subset of 757 compounds (56 %) identified as inside the quantitative model domain, and can handle further 318 compounds (23 %) with the categorical submodel, with 290 compounds (21 %) being outside its domain. The new in silico approach appears useful as ITS (Integrated Testing Strategy) tool for the daphnid toxicity assessment. The discussion includes a comparison of Kow - and LSER-predicted narcosis-level toxicity in the read-across context. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Influences of size-fractionated humic acids on arsenite and arsenate complexation and toxicity to Daphnia magna.

    Science.gov (United States)

    Ren, Jinqian; Fan, Wenhong; Wang, Xiangrui; Ma, Qingquan; Li, Xiaomin; Xu, Zhizhen; Wei, Chaoyang

    2017-01-01

    The intrinsic physicochemical properties of dissolved organic matter (DOM) may affect the mobility and toxicity of arsenic in aquatic environments. In the present study, the humic acid (HA) was ultra-filtered into five fractions according to molecular weight, and their physicochemical properties were characterized. Complexation of HA fractions with arsenite and arsenate was first determined by differential pulse polarography (DPP). The influences of HA fractions on arsenic toxicity were then examined using Daphnia magna as a model organism. As(V) had a higher affinity with HA than As(III), and their complexation was dependent on the total acidity and fluorescence characteristics of DOM. We demonstrated that the acidity and fluorescence also better explained the As toxicity to daphnids than UV absorbance and hydraulic diameter. Arsenic speciation determined by DPP significantly affected the toxicity of arsenite and arsenate. The results extended the free-ion activity model application to the case of arsenic. The present study clearly indicated that DOM with different molecular weights has distinct physicochemical properties, and could influence the speciation and toxicity of As to different extent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. QSAR modeling of toxicity of diverse organic chemicals to Daphnia magna using 2D and 3D descriptors

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Supratik [Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Raja S C Mullick Road, Kolkata 700032 (India); Roy, Kunal, E-mail: kunalroy_in@yahoo.com [Drug Theoretics and Cheminformatics Laboratory, Department of Pharmaceutical Technology, Jadavpur University, Raja S C Mullick Road, Kolkata 700032 (India)

    2010-05-15

    One of the major economic alternatives to experimental toxicity testing is the use of quantitative structure-activity relationships (QSARs) which are used in formulating regulatory decisions of environmental protection agencies. In this background, we have modeled a large diverse group of 297 chemicals for their toxicity to Daphnia magna using mechanistically interpretable descriptors. Three-dimensional (3D) (electronic and spatial) and two-dimensional (2D) (topological and information content indices) descriptors along with physicochemical parameter log K{sub o/w} (n-octanol/water partition coefficient) and structural descriptors were used as predictor variables. The QSAR models were developed by stepwise multiple linear regression (MLR), partial least squares (PLS), genetic function approximation (GFA), and genetic PLS (G/PLS). All the models were validated internally and externally. Among several models developed using different chemometric tools, the best model based on both internal and external validation characteristics was a PLS equation with 7 descriptors and three latent variables explaining 67.8% leave-one-out predicted variance and 74.1% external predicted variance. The PLS model suggests that higher lipophilicity and electrophilicity, less negative charge surface area and presence of ether linkage, hydrogen bond donor groups and acetylenic carbons are responsible for greater toxicity of chemicals. The developed model may be used for prediction of toxicity, safety and risk assessment of chemicals to achieve better ecotoxicological management and prevent adverse health consequences.

  19. Monte Carlo-based quantitative structure-activity relationship models for toxicity of organic chemicals to Daphnia magna.

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A; Veselinović, Aleksandar M; Veselinović, Jovana B; Leszczynska, Danuta; Leszczynski, Jerzy

    2016-11-01

    Quantitative structure-activity relationships (QSARs) for toxicity of a large set of 758 organic compounds to Daphnia magna were built up. The simplified molecular input-line entry system (SMILES) was used to represent the molecular structure. The Correlation and Logic (CORAL) software was utilized as a tool to develop the QSAR models. These models are built up using the Monte Carlo method and according to the principle "QSAR is a random event" if one checks a group of random distributions in the visible training set and the invisible validation set. Three distributions of the data into the visible training, calibration, and invisible validation sets are examined. The predictive potentials (i.e., statistical characteristics for the invisible validation set of the best model) are as follows: n = 87, r(2)  = 0.8377, root mean square error = 0.564. The mechanistic interpretations and the domain of applicability of built models are suggested and discussed. Environ Toxicol Chem 2016;35:2691-2697. © 2016 SETAC. © 2016 SETAC.

  20. QSTR with extended topochemical atom (ETA) indices. 16. Development of predictive classification and regression models for toxicity of ionic liquids towards Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Kunal, E-mail: kunalroy_in@yahoo.com; Das, Rudra Narayan

    2013-06-15

    Highlights: • Ionic liquids are not intrinsically ‘green chemicals’ and require toxicological assessment. • Predictive QSTR models have been developed for toxicity of ILs to Daphnia magna. • Simple two dimensional descriptors were used to reduce the computational burden. • Discriminant and regression based models showed appreciable predictivity and reproducibility. • The extracted features can be explored in designing novel environmentally-friendly agents. -- Abstract: Ionic liquids have been judged much with respect to their wide applicability than their considerable harmful effects towards the living ecosystem which has been observed in many instances. Hence, toxicological introspection of these chemicals by the development of predictive mathematical models can be of good help. This study presents an attempt to develop predictive classification and regression models correlating the structurally derived chemical information of a group of 62 diverse ionic liquids with their toxicity towards Daphnia magna and their interpretation. We have principally used the extended topochemical atom (ETA) indices along with various topological non-ETA and thermodynamic parameters as independent variables. The developed quantitative models have been subjected to extensive statistical tests employing multiple validation strategies from which acceptable results have been reported. The best models obtained from classification and regression studies captured necessary structural information on lipophilicity, branching pattern, electronegativity and chain length of the cationic substituents for explaining ecotoxicity of ionic liquids towards D. magna. The derived information can be successfully used to design better ionic liquid analogues acquiring the qualities of a true eco-friendly green chemical.

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

    Science.gov (United States)

    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.

  2. Study of the combined effects of a peracetic acid-based disinfectant and surfactants contained in hospital effluents on Daphnia magna.

    Science.gov (United States)

    Panouillères, Muriel; Boillot, Clotilde; Perrodin, Yves

    2007-04-01

    Hospital effluents cause environmental problems since they are 5-15 more toxic than urban effluents and they are not subjected to any pre-treatment before being discharged into urban sewage networks. The hypothesis used to explain this toxicity is the presence of disinfectants and detergents. This study is aimed at highlighting the ecotoxicity of a peracetic acid-based disinfectant to Daphnia magna, as well as the combined effects of this disinfectant in binary mixtures with three types of detergent. The detergents used here are: cetyltrimethylammonium bromide (CTAB, cationic), sodium dodecylsulfate (SDS, anionic) and Triton X-100 (TX, non-ionic). The toxicity of the mixtures is studied as a function of five predefined ratios. At the end of the study, we conclude that peracetic acid seems to be slightly toxic to Daphnia magna. Indeed, the efficient concentration inhibiting the mobility of 50% of the population of Daphnia at 24 h (EC50) is 116.6 mg/l. Globally, additive effects are observed for all the binary peracetic acid-detergent mixtures. However, for the peracetic acid-TX mixture, its effects have antagonistic tendencies whereas the peracetic acid-CTAB mixture has slight synergic tendencies. The mixture containing peracetic acid and SDS is slightly antagonistic for ratios containing more than 50% peracetic acid.

  3. Toxicity of Decon Green to Cerlodaphnia Dubla, Daphnia Magna, and Bivrio Fischeri

    Science.gov (United States)

    2004-09-01

    magna, and Vibriofischeri b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Haley, Mark V.; and Kurnas , Carl W. 2E2RDF 5...Effluent Toxicity Assessment Center: Duluth, MN, 1993. 8. Haley, M.V.; Kurnas , C.W.; Chester, N.A.; Muse, W.T. Aquatic Toxicity of the Decontaminating...Ground, MD, 1994; UNCLASSIFIED Report (AD-A280 379). 9. Haley, M.V.; Chester, N.A.; Kurnas , C.W.; Phillips, C.T. Aquatic Toxicity of Decontaminating

  4. Life history response of Daphnia magna to a mixotrophic golden alga, Poterioochromonas sp., at different food levels

    DEFF Research Database (Denmark)

    Zhang, Xue; Hu, Hong-Ying; Perlt, Trine Warming

    2011-01-01

    ’s survival and reproduction were significantly depressed when Poterioochromonas comprised above 50%, likely due to the inhibition of food ingestion. Large juveniles were less sensitive to poor quality food than neonates. Therefore, Poterioochromonas may affect D. magna living to various extents depending...

  5. Quantitative structure-activity analyses of anilines and phenols toxicity to Daphnia magna Straus%苯胺和苯酚对大型溞Daphnia magna Straus毒性的定量结构-活性分析

    Institute of Scientific and Technical Information of China (English)

    蒋司同; 聂长明; 林英武; 石春雨

    2011-01-01

    本文旨在对苯胺和苯酚对大型溞Daphnia magna Straus毒性,进行定量结构-活性关系(QSARs)研究并进行相关的预测。由多元线性回归分析(MLR)方法得到的几个主要的QSARs关系模型揭示,在苯胺和苯酚对大型涵毒性中,正辛醇/水分配系数(logKow)是1个决定性因素。而单纯的利用logKow进行模型建立并不能得到很好的结果,在logKow模型的基础上,通过引入其它极性和/或电性参数可以大大提前模型的稳定性和预测能力,本文中所引用的极性参数为价电子数(NVE),电性参数有苯环碳原子Mulliken电荷之和(Qn)、最低非占据轨道能量(ELUMO)和最高占据轨道能量(EHOMO)。总体而言,通过引入1~2个参数即可获得稳定满意的关系模型。此外,引入5个参数可获得最佳关系模型[pEC50=0.054 NVE+0.394logKow-5.863 EHOMO+7.730 ELUMO+0.182 QA-1.062,N=34,R2=0.9328]。本文同时就与QSARs密切相关的参数进行了进一步讨论,为苯胺和苯酚毒性的分子机制提供了新信息。%This paper was aimed at developing quantitative structure-activity relationships (QSARs) for predicting the toxicity of anilines and phenols to Daphnia magna Straus. As analyzed by a method of multiple linear regression (MLR), the resultant QSARs revealed that octanol/water partition coefficient (logKow) is a major determining parameter. A model with logKow was further improved by adding other polarity and/or electronic parameters, such as the number of valence electrons (NVE), the sum of Mulliken charge of C atoms on benzene ring (QA), the energy of the lowest tmoccupied molecular orbital (ELUMO) and the highest occupied molecular orbital (EHOMO). In general, more stable and satisfactory models could be established by adding one or two additional parameters. Moreover, a best model was obtained by using five parameters [pEC50 = 0.054 NVE + 0.394logKow - 5.863 EHOMO + 7.730 ELUMO + 0.182 QA- 1.062, N= 34, R2 = 0

  6. Prediction of acute toxicity of emerging contaminants on the water flea Daphnia magna by Ant Colony Optimization-Support Vector Machine QSTR models.

    Science.gov (United States)

    Aalizadeh, Reza; von der Ohe, Peter C; Thomaidis, Nikolaos S

    2017-03-22

    According to the European REACH Directive, the acute toxicity towards Daphnia magna should be assessed for any industrial chemical with a market volume of more than 1 t/a. Therefore, it is highly recommended to determine the toxicity at a certain confidence level, either experimentally or by applying reliable prediction models. To this end, a large dataset was compiled, with the experimental acute toxicity values (pLC50) of 1353 compounds in Daphnia magna after 48 h of exposure. A novel quantitative structure-toxicity relationship (QSTR) model was developed, using Ant Colony Optimization (ACO) to select the most relevant set of molecular descriptors, and Support Vector Machine (SVM) to correlate the selected descriptors with the toxicity data. The proposed model showed high performance (QLOO(2) = 0.695, Rfitting(2) = 0.920 and Rtest(2) = 0.831) with low root mean square errors of 0.498 and 0.707 for the training and test set, respectively. It was found that, in addition to hydrophobicity, polarizability and summation of solute-hydrogen bond basicity affected toxicity positively, while minimum atom-type E-state of -OH influenced toxicity values in Daphnia magna inversely. The applicability domain of the proposed model was carefully studied, considering the effect of chemical structure and prediction error in terms of leverage values and standardized residuals. In addition, a new method was proposed to define the chemical space failure for a compound with unknown toxicity to avoid using these prediction results. The resulting ACO-SVM model was successfully applied on an additional evaluation set and the prediction results were found to be very accurate for those compounds that fall inside the defined applicability domain. In fact, compounds commonly found to be difficult to predict, such as quaternary ammonium compounds or organotin compounds were outside the applicability domain, while five representative homologues of LAS (non-ionic surfactants) were, on average

  7. Gravity receptors in a microcrustacean water flea - Sensitivity of antennal-socket setae in Daphnia magna

    Science.gov (United States)

    Meyers, D. G.; Farmer, J. M.

    1982-01-01

    Gravity receptors of Dephnia magna were discovered on the basal segment of the swimming antennae and were shown to respond to upward water currents that pass the animal as it sinks between swimming strokes. Sensitivity of the gravity perceiving mechanism was tested by subjecting daphnids to a series of five decreasingly dense aqueous solutions (neutral density to water) in darkness (to avoid visual cues). Three-dimensional, video analysis of body position (pitch, yaw and roll) and swimming path (hop and sink, vertical and horizontal patterns) revealed a gradual threshold that occurred near a density difference between the animal and its environment of less than 0.25%. Because daphnids do not sink but continue to slide after stroking in the increased density solutions, gravity perception appears to occur during a vertical swing of the longitudinal body axis to the vertical plane, about their center of gravity, and, thereby, implies a multidirectional sensitivity for the antennal-socket setae.

  8. Effects of iron sulfate dosage on the water flea (Daphnia magna Straus) and early development of carp (Cyprinus carpio L.).

    Science.gov (United States)

    van Anholt, R D; Spanings, F A T; Knol, A H; van der Velden, J A; Wendelaar Bonga, S E

    2002-02-01

    Adult water fleas, Daphnia magna Straus, and the early life stages of carp, Cyprinus carpio L., were exposed to river water near an iron sulfate dosage installation to determine the effects of phosphate precipitation with iron(II)sulfate. Tests were conducted during two consecutive dosage periods of 3,000 and 5,000 kg/day iron sulfate (520 and 620 microg/L total Fe respectively) at the dosage site and at a reference site (60 microg/L total Fe) further downstream. Though survival remained unaffected, the filter-feeding D. magna accumulated iron and other metals at the dosage site. Viability of offspring was strongly reduced at the highest dose of iron sulfate compared to the lower dose and the reference site. Specific staining of microscopic sections revealed a strong accumulation of iron(III) in the digestive tract. The egg membranes of the carp embryos accumulated not only substantial amounts of iron but also other metals, including cadmium and aluminium. Hardly any of the metals passed the egg membranes and reached the embryos. After hatching the accumulation of cadmium by the larvae increased rapidly and iron levels were elevated at the highest dose of iron sulfate, parallel with the onset of exogenous feeding. Iron(III) particles were observed in the intestines at histological examination. In addition, at 620 microg/L total Fe a strong increase in whole-body levels of the stress hormone cortisol was observed in the carp larvae, indicating a physiological response to adverse conditions. The results indicate that the rapid oxidation of free Fe2+ into iron(III) forms and the precipitation of iron(III) into larger particles resulted in a low acute toxicity of the river water directly at the iron sulfate dosage site. The observed chronic and sublethal effects at the dosage site probably resulted from the intestinal uptake of iron(III) and other toxic metals associated with the food particles. However, these effects could no longer be observed at the reference site

  9. Is ultraviolet radiation a synergistic stressor in combined exposures? The case study of Daphnia magna exposure to UV and carbendazim.

    Science.gov (United States)

    Ribeiro, Fabianne; Ferreira, Nuno C G; Ferreira, Abel; Soares, Amadeu M V M; Loureiro, Susana

    2011-03-01

    The toxicological assessment of chemical compounds released to the environment is more accurate when mixtures of chemicals and/or interactions between chemicals and natural stressors are considered. Ultraviolet radiation can be taken as a natural stressor since the levels of UV are increasing due to the decrease of its natural filter, the stratospheric ozone concentration. Therefore, a combination of chemical exposures and increasing UV irradiance in aquatic environments is likely to occur. In the current study, combined effects of carbendazim and ultraviolet radiation were evaluated, using selected life traits as endpoints on Daphnia magna. To design combined exposures, first single chemical and natural stressor bioassays were performed: a reproduction test with carbendazim and a reproduction, feeding inhibition and Energy budget test with ultraviolet radiation. Following single exposures, the combinations of stressors included exposures to UV radiation and carbendazim for a maximum exposure time of 4h, followed by a post-exposure period in chemically contaminated medium for a maximum of 15 days, depending on the endpoint, where the effects of the combined exposures were investigated. Statistical analyses of the data set were performed using the MixTox tool and were based on the conceptual model of Independent Action (IA) and possible deviations to synergism or antagonism, dose-ratio or dose-level response pattern. Both ultraviolet radiation and carbendazim as single stressors had negative impacts on the measured life traits of daphnids, a decrease on both feeding rates and reproduction was observed. Feeding rates and reproduction of D. magna submitted to combined exposures of ultraviolet radiation and carbendazim showed a dose-ratio deviation from the conceptual model as the best description of the data set, for both endpoints. For feeding inhibition, antagonism was observed when the UV radiation was the dominant item in combination, and for reproduction

  10. Toxic effects of diclofenac on life history parameters and the expression of detoxification-related genes in Daphnia magna.

    Science.gov (United States)

    Liu, Yang; Wang, Lan; Pan, Benben; Wang, Chao; Bao, Shuang; Nie, Xiangping

    2017-02-01

    Diclofenac (DCF), as a widely used drug, has been detected in various environmental media such as municipal wastewater effluent. However, there is little information on the effects of DCF on freshwater invertebrates potentially exposing to its residues in surface water. In the present study, we investigated the toxic effects of DCF on the physiological parameters (e.g., survival, growth rate, and reproduction) of a crustacean, Daphnia magna, via a 21-d chronic toxicity test, and we also evaluated the effects of DCF on the expression of the genes related to the detoxification metabolism, growth, development and reproduction (e.g., HR96, P-gp, CYP360A8, CYP314, GST, EcR and Vtg) in acute exposure (up to 96h) with RT-PCR. Significant toxic effects of DCF to D. magna were observed at 50μgL(-1), the expression of these selected genes was inhibited with 24h of exposure, and induced after 48h to some extents. The expression of Vtg was induced at high concentrations of DCF (500μgL(-1) and 5000μgL(-1)) after 24h and 48h of exposure, but also significantly induced at low concentration (50μgL(-1)) after 96h of exposure. Dose- and time-dependent relationships were observed for gene expression of the seven selected genes. In the 21-d chronic toxicity test, the days to the first brood and the days to the first egg production were both significantly delayed at 50μgL(-1). However, there were no significant differences observed among the molting frequency, number of eggs produced in the first brood, total number of eggs per individual, total number of broods per individual, body length and intrinsic growth rate. Our results suggested that the reproduction parameters are more sensitive endpoints than the survival and growth for evaluating the toxicity of DCF to aquatic invertebrates. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Daphnia magna Straus, 1820 response to sediment samples from a contaminated river ( Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Nara Regina Terra

    2013-03-01

    Full Text Available AIM: The Sinos River, a tributary of Guaíba Lake, is 200 km long from the headwaters to the mouth and is influenced by several sources of pollution. A study to learn more about conditions in this river was performed in the middle and lower reaches. The study evaluated the effects of sediment contamination by xenobiotics on the survival and reproduction of Daphnia magna. METHODS: Eight sediment samples were collected per site from Dec/2007 to Aug/2009, as a substrate for 480 young cladocera (2-26 h old at the beginning of the trials in chronic toxicity tests (21 days. For this purpose, D. magna individuals were exposed to sediment and M4 culture medium, at a proportion of 1:4 (v:v using 50 mL beakers, kept at 20 ºC ± 2 ºC in 16h light:8h dark cycles. The test organisms came from lots with LC50-24h = 1.04 mgK2Cr2O7 ± 0.11 mg. Percentage survival and reproduction were considered to define acute and/or chronic responses. Duncan (p < 0.05 and T (p < 0.05 Tests, ANOVA and Spearman correlation of the biological data were used as statistical complementation. The Spearman correlation was also applied looking for dependencies between the rainfall measured at the sites and the biological parameters but there was no evidence of correlation. The presence of acute toxicity was diagnosed for the sample in which survival was less than 80%, and for chronic toxicity when the mean number of neonates was less than 20 daphniids. RESULTS: Reproductive delays were found coinciding with physical and chemical parameters, as well as the presence of metals at values that were not in accordance with the law. Statistical analysis suggested the predominance of point sources of contamination. An effect on survival was observed in 17% of the samples, and on reproduction in 87%. CONCLUSIONS: This study found that pollutants discharged into the Sinos River remain and can interfere in the equilibrium of the trophic network, since they increase mortality and diminish the

  12. Nutritional value content, biomass production and growth performance of Daphnia magna cultured with different animal wastes resulted from probiotic bacteria fermentation

    Science.gov (United States)

    Endar Herawati, Vivi; Nugroho, R. A.; Pinandoyo; Hutabarat, Johannes

    2017-02-01

    Media culture is an important factor for the growth and quality of Daphnia magna nutrient value. This study has purpose to find the increasing of nutritional content, biomass production and growth performance of D. magna using different animal wastes fermented by probiotic bacteria. This study conducted using completely randomized experimental design with 10 treatments and 3 replicates. Those media used different animal manures such as chicken manure, goat manure and quail manure mixed by rejected bread and tofu waste fermented by probiotic bacteria then cultured for 24 days. The results showed that the media which used 50% chicken manure, 100% rejected bread and 50% tofu waste created the highest biomass production, population and nutrition content of D.magna about 2111788.9 ind/L for population; 342 grams biomass production and 68.85% protein content. The highest fatty acid profile is 6.37% of linoleic and the highest essential amino acid is 22.8% of lysine. Generally, the content of ammonia, DO, temperature, and pH during the study were in the good range of D. magna’s life. This research has conclusion that media used 50% chicken manure, 100% rejected bread and 50% tofu waste created the highest biomass production, population and nutrition content of D. magna.

  13. Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

    Science.gov (United States)

    Pan, Ying; Yan, Shi-Wei; Li, Ruo-Zhu; Hu, Yi-Wen; Chang, Xue-Xiu

    2017-01-01

    Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L‑1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L‑1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function.

  14. Growth and Survival Rate of Tilapia (Oreochromis niloticus Larvae Fed by Daphnia magna Cultured With Organic Fertilizer Resulted From Probiotic Bacteria Fermentation

    Directory of Open Access Journals (Sweden)

    Vivi Endar Herawati

    2015-10-01

    Full Text Available Daphnia magna is a potential feed for fish. The aim of this research was to find the best treatment and effect of D. magna culture addition from fermented organic fertilizer, to growth and survival rate of Oreochromis niloticus larvae. There were five treatments, each with three repetitions used in the study. All treatments used chicken dung, and different combinations of rice bran, coconut oilcake waste and tilapia larvae. Feeding on tilapia was given by ad libitum method for five times a day until 14 days. Water quality during the research was maintained at temperature 28–29°C, DO 0.3 ppm and pH 8.1–8.2. Observed variables include relative growth rate, survival rate, food consumption rate and water quality. Our results showed that D. magna cultured by fermented organic fertilizer for tilapia larvae (O. niloticus had high significant effect (p < 0.01 on the relative growth rate and survival rate. Treatment of D. magna cultured by 1.2 g/L chicken manure, 0.9 g/L rice bran and 0.3 g/L coconut oilcake showed the highest value on the relative growth rate (10.86%; survival rate (98.46% and food consumption at first week (106.43% and second week (152.76%.

  15. Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

    Science.gov (United States)

    Pan, Ying; Yan, Shi-wei; Li, Ruo-zhu; Hu, Yi-wen; Chang, Xue-xiu

    2017-01-01

    Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L−1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L−1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function. PMID:28079143

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Stress-responsive expression of a glutathione S-transferase (delta) gene in waterflea Daphnia magna challenged by microcystin-producing and microcystin-free Microcystis aeruginosa.

    Science.gov (United States)

    Lyu, Kai; Gu, Lei; Li, Bangping; Lu, Yichun; Wu, Changcan; Guan, Haoyong; Yang, Zhou

    2016-06-01

    Harmful cyanobacterial blooms resulting from eutrophication and global warming have emerged as a worldwide environmental concern. Some zooplankton populations, including Daphnia, have been shown to adapt locally to microcystin-producing Microcystis. Previous in vitro experiments indicate that glutathione-S-transferase (GST) may act as the first step of detoxification in Daphnia by conjugating microcystins (MCs) with glutathione. The GST family is categorized into many classes, and different classes present distinct responses to MC detoxification. To date, however, the molecular mechanism of single class GST participation in buffering the toxic effects of MCs in Daphnia remains poorly known. In this study, a full-length delta-GST cDNA of Daphnia magna (Dm-dGST) was isolated and characterized through bioinformatics. Differential gene expression studies revealed that short-term exposure to microcystin-producing (MP) Microcystis aeruginosa increased Dm-dGST transcript levels. By contrast, long-term exposure to MP or microcystin-free (MF) M. aeruginosa decreased Dm-dGST transcript levels. Together with changes in three other antioxidation biomarkers (catalase, CuZn- and Mn-superoxide dismutase), it is concluded that Dm-dGST can potentially biotransform MCs to reduce their toxicity. The present study highlights the importance of Dm-dGST in response to MC toxicity and may thus facilitate future research on the molecular mechanisms of MC tolerance in zooplankton under an increasing eutrophic world.

  18. Interactive effects of a bacterial parasite and the insecticide carbaryl to life-history and physiology of two Daphnia magna clones differing in carbaryl sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    De Coninck, Dieter I.M., E-mail: Dieter.DeConinck@UGent.be [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium); De Schamphelaere, Karel A.C. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium); Jansen, Mieke; De Meester, Luc [Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Ch. Deberiotstraat 32, B-3000 Leuven (Belgium); Janssen, Colin R. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Ghent (Belgium)

    2013-04-15

    Highlights: ► Interactive effects between a bacterial parasite and an insecticide in Daphnia magna. ► Two D. magna clones differing strongly in their sensitivity to the insecticide. ► Effects studied on various life-history and physiological endpoints. ► Genetic differences in strength and direction of interaction effects. -- Abstract: Natural and chemical stressors occur simultaneously in the aquatic environment. Their combined effects on biota are usually difficult to predict from their individual effects due to interactions between the different stressors. Several recent studies have suggested that synergistic effects of multiple stressors on organisms may be more common at high compared to low overall levels of stress. In this study, we used a three-way full factorial design to investigate whether interactive effects between a natural stressor, the bacterial parasite Pasteuria ramosa, and a chemical stressor, the insecticide carbaryl, were different between two genetically distinct clones of Daphnia magna that strongly differ in their sensitivity to carbaryl. Interactive effects on various life-history and physiological endpoints were assessed as significant deviations from the reference Independent Action (IA) model, which was implemented by testing the significance of the two-way carbaryl × parasite interaction term in two-way ANOVA's on log-transformed observational data for each clone separately. Interactive effects (and thus significant deviations from IA) were detected in both the carbaryl-sensitive clone (on survival, early reproduction and growth) and in the non-sensitive clone (on growth, electron transport activity and prophenoloxidase activity). No interactions were found for maturation rate, filtration rate, and energy reserve fractions (carbohydrate, protein, lipid). Furthermore, only antagonistic interactions were detected in the non-sensitive clone, while only synergistic interactions were observed in the carbaryl sensitive clone

  19. Correlating toxicological effects of ionic liquids on Daphnia magna with in silico calculated linear free energy relationship descriptors.

    Science.gov (United States)

    Cho, Chul-Woong; Yun, Yeoung-Sang

    2016-06-01

    In silico prediction model for toxicological effects of ionic liquids (ILs) is useful to understand ILs' toxicological interactions and to design environmentally benign IL structures. Actually, it is essential since the types of ILs are extremely numerous. Accordingly, prediction models were developed in this study. For the modelling, well-defined linear free energy relationship (LFER) descriptors - i.e. excess molar refraction (E), dipolarity/polarizability (S), H-bonding acidity (A), H-bonding basicity (B), McGowan volume (V), cation interaction (J(+)) and anion interaction (J(-)) - were in silico calculated using density functional theory and conductor-like screening model. These descriptors were then correlated with the toxicological values of ILs to Daphnia magna. First, a model established by Hoover et al. (2007) using measured LFER descriptors of 97 neutral compounds was applied to the prediction of ILs' toxicity. As expected, the model by Hoover et al. (2007) needs to be amended for ILs. To that end, the difference in toxicological interactions between neutral compounds and ILs was addressed by additional single J(+) or five LFER descriptors of cation i.e. Ec, Sc, Bc, Vc, and J(+). Secondly, a prediction model for only ILs was developed by using the three LFER descriptors Ec, Bc, and J(+). The model had a reasonable predictability and robustness of R(2) = 0.880 for the training set, 0.848 for the test set, and 0.867 for the overall set. The established models can be used to design environmentally benign IL structures and to reduce labour, danger, time, and materials compared to the experiment-based study.

  20. Multi-metal interactions between Cd, Cu, Ni, Pb and Zn in water flea Daphnia magna, a stable isotope experiment.

    Science.gov (United States)

    Komjarova, I; Blust, R

    2008-11-11

    Metal interaction effects were investigated in Daphnia magna during a simultaneous exposure to essential (Cu, Ni and Zn) and non-essential (Cd and Pb) metals at environmentally relevant concentrations using a stable isotope technique. The metals were applied in the following concentration ranges: 0.0125-0.2 microM for (106)Cd, 0.025-0.25 microM for (65)Cu and (204)Pb, 0.1-1.25 microM for (62)Ni and (67)Zn. Cadmium and copper exhibited a suppressing effect on the uptake rates of all other metals present in the mixture with the exception to lead at all studied concentrations. The effect was already pronounced at low Cd and Cu concentrations and reached a maximum at the higher concentrations. Nickel and zinc showed weaker interactions with cadmium and between each other, while having no effect on copper and lead uptake. There was a high degree of correlation between Cd, Ni and Zn uptake rates indicating that these metals share in part common uptake or interaction pathways. Moreover, a significant correlation between Zn and Cu uptake processes suggests that more than one mechanism is involved in Zn accumulation since Cu is known to interact with Na uptake sites. The uptake of lead was marked by a high initial rate, but the uptake process reached saturation within 24 h. Cd applied at a concentration of 0.2 microM was the only metal which affected the lead uptake process by stimulation of the Pb uptake. Added to the medium at a concentration of 0.25 microM, lead in turn, increased copper uptake. Current work illustrates that metal interactions are significant and occur at low environmentally realistic concentrations affecting bioavailability of both toxic and essential metals.

  1. Evaluating the ameliorative effect of natural dissolved organic matter (DOM) quality on copper toxicity to Daphnia magna: improving the BLM.

    Science.gov (United States)

    Al-Reasi, Hassan A; Smith, D Scott; Wood, Chris M

    2012-03-01

    Various quality predictors of seven different natural dissolved organic matter (DOM) and humic substances were evaluated for their influence on protection of Daphnia magna neonates against copper (Cu) toxicity. Protection was examined at 3 and 6 mg l(-1) of dissolved organic carbon (DOC) of each DOM isolate added to moderately hard, dechlorinated water. Other water chemistry parameters (pH, concentrations of DOC, calcium, magnesium and sodium) were kept relatively constant. Predictors included absorbance ratios Abs(254/365) (index of molecular weight) and Abs-octanol(254)/Abs-water(254) (index of lipophilicity), specific absorption coefficient (SAC(340); index of aromaticity), and fluorescence index (FI; index of source). In addition, the fluorescent components (humic-like, fulvic-like, tryptophan-like, and tyrosine-like) of the isolates were quantified by parallel factor analysis (PARAFAC). Up to 4-fold source-dependent differences in protection were observed amongst the different DOMs. Significant correlations in toxicity amelioration were found with Abs(254/365), Abs-octanol(254)/Abs-water(254), SAC(340), and with the humic-like fluorescent component. The relationships with FI were not significant and there were no relationships with the tryptophan-like or tyrosine-like fluorescent components at 3 mg C l(-1), whereas a negative correlation was seen with the fulvic-like component. In general, the results indicate that larger, optically dark, more lipophilic, more aromatic DOMs of terrigenous origin, with higher humic-like content, are more protective against Cu toxicity. A method for incorporating SAC(340) as a DOM quality indicator into the Biotic Ligand Model is presented; this may increase the accuracy for predicting Cu toxicity in natural waters.

  2. QSAR models for toxicity of organic substances to Daphnia magna built up by using the CORAL freeware.

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A; Benfenati, Emilio; Gini, Giuseppina

    2012-03-01

    CORAL (CORrelations And Logic, http://www.insilico.eu/coral/) is a freeware available on the Internet. This freeware is designed to build up quantitative structure - property/activity relationships. The molecular structure for CORAL should be represented by the simplified molecular input line entry system (SMILES). Optimal descriptors calculated with SMILES are a mathematical function of the presence or absence of SMILES elements. The essence of this approach is the calculation of correlation weights for each element or combination of the elements by the Monte Carlo method. These coefficients serve to calculate the descriptors correlated with the endpoint for the training set, hoping that this correlation will also hold for the external test set. These descriptors can be improved by taking into account global physicochemical situations in molecules. An example of the physicochemical situation is the presence of oxygen and nitrogen. One can calculate these situations with SMILES and represent them by combining 0 (absence) and 1 (presence). The involving in the modelling of correlation weights of aforementioned physicochemical situations gave improvement in accuracy of models of toxicity to Daphnia magna for test set: n(test) = 75, r(2) = 0.7322, r(2) (pred) = 0.7193, r(2) (m) = 0.6549 (without correlation weights of the physicochemical situations); and n(test) = 75, r(2) = 0.7897, r(2) (pred) = 0.7790, r(2) (m) = 0.6850 (with aforementioned correlation weights of physicochemical situations). © 2011 John Wiley & Sons A/S.

  3. n vivo retention of ingested Au NPs by Daphnia magna: No evidence for trans-epithelial alimentary uptake

    Science.gov (United States)

    Khan, Farhan R.; Kennaway, Gabrielle M.; Croteau, Marie-Noële; Dybowska, Agnieszka; Smith, Brian D.; Nogueira, António J.A.; Rainbow, Philip S.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2014-01-01

    In vivo studies with Daphnia magna remain inconclusive as to whether engineered nanoparticles (NPs) are internalized into tissues after ingestion. Here we used a three-pronged approach to study the in vivo retention and efflux kinetics of 20 nm citrate stabilized Au NPs ingested by this key aquatic species. Daphnids were exposed to suspended particles (600 μg L−1) for 5 h after which they were depurated for 24 h in clean water containing algae. Light microscopy was used to follow the passage of Au NPs through the gastrointestinal tract, Au body burdens were determined by ICP-MS (inductively coupled plasma mass spectrometry), and transmission electron microscopy (TEM) was used to examine the presence and distribution of Au NPs in tissues. Results revealed that the elimination of Au NPs was bi-phasic. The fast elimination phase lasted −1 (±SE) which accounted for ∼75% of the ingested Au. The remaining ∼25% of the ingested Au NPs was eliminated at a 100-fold slower rate. TEM analysis revealed that Au NPs in the midgut were in close proximity to the peritrophic membrane after 1 and 24 h of depuration. There were no observations of Au NP uptake at the microvilli. Thus, although Au NPs were retained in the gut lumen, there was no observable internalization into the gut epithelial cells. Similar to carbon nanotubes and CuO NPs, our findings indicate that in daphnids the in vivo retention of Au NPs does not necessarily result in their internalization.

  4. Behavior and chronic toxicity of two differently stabilized silver nanoparticles to Daphnia magna

    DEFF Research Database (Denmark)

    Sakka, Yvonne; Skjolding, Lars Michael; Mackevica, Aiga;

    2016-01-01

    While differences in silver nanoparticle (AgNP) colloidal stability, surface potential, or acute aquatic toxicity for differently stabilized AgNP have often been reported, these have rarely been studied in long-term ecotoxicity tests. In the current study, we investigated the chronic toxicity of Ag...... types of AgNP during a typical media exchange period in the D. magna test for chronic toxicity. As expected, the sterically stabilized AgNP were more stable in the test medium, also in the presence of food; however, a higher uptake of silver after 24 h exposure of the charge stabilized AgNP was found...... compared to the detergent-stabilized AgNP (0.046 ± 0.006 μg Ag μg DW−1 and 0.023 ± 0.005 μg Ag μg DW−1, respectively). In accordance with this, the higher reproductive effects and mortality were found for the charge-stabilized than for the sterically-stabilized silver nanoparticles in 21-d tests...

  5. Introduction of foreign DNA into the water flea, Daphnia magna, by electroporation.

    Science.gov (United States)

    Kato, Yasuhiko; Kobayashi, Kaoru; Watanabe, Hajime; Iguchi, Taisen

    2010-03-01

    Daphnids inhabit a diverse array of aquatic environments and they are a good model for understanding response and adaptation to environmental changes and they have been used one of standard organisms in ecotoxicology. Recent progress of genomics changed the tools for analyzing responses of daphnids, because gene expression changes can be observed before the emergence of prominent adverse effect such as immobility of the organism. Thus understanding of biological changes from gene expression level can be one of the sensitive tools for the evaluation of environmental response of organisms. However, there was no technique for genetic manipulation in daphnids. Hence, we have developed a gene introduction technique based on electroporation. There are two critical points for the successful introduction of foreign DNA into D. magna. (1) Injection of DNA into blood stream. (2) Usage of very low voltage for the electroporation. The injected DNA containing green fluorescent protein (GFP) could be introduced daphnids and the expression of GFP could be detected in living daphnids. This is the first report of gene introduction to daphnids and, together with the emerging genome sequences, will be useful for the expanding our use of daphnid in ecotoxicology.

  6. Transmission Electron Microscopy and Scanning Transmission X-Ray Microscopy Studies on the Bioaccumulation and Tissue Level Absorption of TiO2 Nanoparticles in Daphnia magna.

    Science.gov (United States)

    Kwon, Dongwook; Nho, Hyun Woo; Yoon, Tae Hyun

    2015-06-01

    In this study, bioaccumulation and tissue-level absorption of TiO2 nanoparticles (NPs) in freshwater invertebrates were investigated using transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM). The TiO2 NPs were used to test impacts of core sizes (i.e., 5 ± 2 nm and 23 ± 7 nm for TiO2(SYN) and TiO2(P25), respectively) and agglomerations (i.e., well dispersed vs. highly agglomerated) on the uptake of TiO2 NPs in Daphnia magna (D. magna). Highly agglomerated TiO2 NPs, regardless of their core sizes, were heavily taken up into the digestive tract of D. magna and no detectable penetration of both TiO2 NPs into the gut epithelial cells of D. magna was observed in TEM and STXM images. However, significant damages involving morphological changes in the microvilli and gut epithelial cells (e.g., irregular shaped microvilli, epithelial cell protrusion, and dilatation of cytoplasmic inclusion) were observed only with the commercial TiO2 NPs (TiO2(P25)) with larger core size and mixed crystalline phase, while the laboratory synthesized TiO2 NPs (TiO2(Syn)) with smaller core size and single crystalline phase showed slight morphological changes in the gut microvilli and epithelial cells. In the case of D. magna exposed to the well dispersed synthetic TiO2 NP ((Cit)TiO2(Syn)), only a negligible amount of TiO2 NPs were found within the digestive tract of the D. magna without any significant damages in the gut microvilli and epithelial cells and any detectable penetrations of TiO2 NPs into epithelial cells of D. magna gut. These TEM and STXM observations confirmed us that uptake of NP into D. magna are strongly dependent on their agglomeration (i.e., hydrodynamic sizes), rather than their core sizes, while direct penetration of NPs into tissues of digestive tract seems unlikely without significant morphological changes (e.g., collapse of the epithelial tissue) caused by high toxicity of NPs or released metal ions.

  7. Combining physico-chemical analysis with a Daphnia magna bioassay to evaluate a recycling technology for drinking water treatment plant waste residuals.

    Science.gov (United States)

    Chen, Ting; Xu, Yongpeng; Zhu, Shijun; Cui, Fuyi

    2015-12-01

    Recycling water treatment plant (WTP) waste residuals is considered to be a feasible method to enhance the efficiency of pollutant removal. This study also evaluated the safety and water quality of a pilot-DWTP waste residuals recycling technology by combining physical-chemistry analysis with a Daphnia magna assay. The water samples taken from each treatment step were extracted and concentrated by XAD-2 resin and were then analyzed for immobilization and enzyme activity with D. magna. The measured parameters, such as the dissolve organic carbon (DOC), UV254 and THM formation potential (THMFPs) of the recycling process, did not obviously increase over 15 days of continuous operation and were even lower than typical values from a conventional process. The extract concentration ranged from 0 to 2 Leq/ml as measured on the 7th and 15th days and the immobilization of D. magna exposed to water treated by the recycling process was nearly equivalent to that of the conventional process. Both the superoxide dismutase (SOD) and the catalase (CAT) activity assay indicated that a lower dose of water extract (0.5, 1, 1.5 Leq/ml) could stimulate the enzyme activity of D. magna, whereas a higher dose (2 Leq/ml at the sampling point C3, R3, R4 ) inhibits the activity. Moreover, the SOD and CAT activity of D. magna with DOC and UV254 showed a strong concentration-effect relationship, where the concentration range of DOC and UV254 were 4.1-16.2 mg/L and 0.071-4.382 cm(-1), respectively. The results showed that there was no statistically significant difference (p>0.05) between the conventional and recycling treatment processes and the toxicity of water samples in the recycling process did not increase during the 15-day continuous recycling trial. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Acute toxicity and environmental risk of teflubenzuron to Daphnia magna, Poecilia reticulata and Lemna minor in the absence and presence of sediment.

    Science.gov (United States)

    Medeiros, Louise S; Souza, Jaqueline P; Winkaler, Elissandra U; Carraschi, Silvia P; Cruz, Claudinei; Souza-Júnior, Severino C; Machado-Neto, Joaquim G

    2013-01-01

    This study aimed to estimate the acute toxicity of teflubenzuron (1-(3,5-dichloro-2,4-difluorophenyl)-3-(2,6-difluorobenzoyl)urea) (TFB) for Daphnia magna, Lemna minor and Poecilia reticulata, in the absence and presence of sediment; evaluate the effect of sediment on the TFB bioavailability; and to classify this insecticide according to its environmental poisoning risk for agricultural and aquaculture uses. The tests of TFB acute toxicity were conducted in static system in a completely randomized design with increasing TFB concentrations, and a control group. The TFB has been classified according to the estimated values of EC50 and LC50 by its acute toxicity and environmental risk. The sediment significantly reduced toxicity and bioavailability of TFB in water column. Therefore, the insecticide can be classified as being highly toxic to Daphnia magna, which means the agricultural and aquacultural uses of TFB pose a high risk of environmental toxicity to non-target organisms. However, it was practically non-toxic to L. minor and P. reticulata.

  9. Variable toxicity of silver nanoparticles to Daphnia magna: effects of algal particles and animal nutrition.

    Science.gov (United States)

    Conine, Andrea L; Frost, Paul C

    2017-01-01

    Aquatic environments vary widely in aspects other than their physicochemical properties that could alter the toxicity of novel contaminants. One factor that could affect chemical toxicity to aquatic consumers is their nutritional environment as it can strongly affect their physiology and life history. Nutrition has the potential to alter an organism's response to the toxin or how the toxin interacts with the consumer through its food. Here we determined how growth and survival responses of Daphnia to an emerging contaminant, silver nanoparticles (AgNPs), are affected by the presence of food and its stoichiometric food quality. We used a series of survival tests, each slightly modified, to determine whether variable toxicity in different nutritional environments resulted from algal sequestration of AgNPs in a nontoxic form or from changes to the nutritional status of the test animals. We found that the presence of algae, of good or poor quality, reduced the toxicity of AgNPs on animal growth and survival. However, the decrease in AgNP toxicity was greater for animals consuming P-rich compared to P-poor food. We found evidence that this effect of food quality was due to greater algal uptake of AgNPs by P-rich than by P-stressed algae. However, we also found animal nutrition, in the absence of algal AgNP binding, could affect toxicity with P-nourished animals surviving slightly better when exposed to AgNPs compared to their P-stressed counterparts. Our results show an important role for algal particles and their P content in determining the toxicity of AgNPs in natural waters primarily due to their binding and uptake abilities and, less so, to their effects on animal nutrition.

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

    Directory of Open Access Journals (Sweden)

    Courts Cornelius

    2009-11-01

    Full Text Available Abstract 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

  11. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: implications for regulatory study designs and ecological risk assessments for GM crops.

    Science.gov (United States)

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed.

  12. Metallothionein and Hsp70 trade-off against one another in Daphnia magna cross-tolerance to cadmium and heat stress

    Energy Technology Data Exchange (ETDEWEB)

    Haap, Timo, E-mail: timo.haap@gmx.de; Schwarz, Simon; Köhler, Heinz-R.

    2016-01-15

    Highlights: • Cadmium acclimation of two Daphnia magna clones which differed in Cd sensitivity and Hsp70 levels. • Two distinct metal-handling strategies regarding Hsp70 and MT expression were observed. • High Hsp70 levels did not confer an increase in Cd and heat stress tolerance. • Our results indicate a trade-off between Hsp70 and MT. - Abstract: The association between the insensitivity of adapted ecotypes of invertebrates to environmental stress, such as heavy metal pollution, and overall low Hsp levels characterizing these organisms has been attracting attention in various studies. The present study seeks to induce and examine this phenomenon in Daphnia magna by multigenerational acclimation to cadmium in a controlled laboratory setting. In this experiment, interclonal variation was examined: two clones of D. magna that have previously been characterized to diverge regarding their cadmium resistance and levels of the stress protein Hsp70, were continuously exposed to a sublethal concentration of Cd over four generations to study the effects of acclimation on Hsp70, metallothionein (MT), reproduction and cross-tolerance to heat stress. The two clones differed in all the measured parameters in a characteristic way, clone T displaying Cd and heat resistance, lower Hsp70 levels and offspring numbers on the one hand and higher MT expression on the other hand, clone S the opposite for all these parameters. We observed only slight acclimation-induced changes in constitutive Hsp70 levels and reproductive output. The differences in MT expression between clones as well as between acclimated organisms and controls give evidence for MT accounting for the higher Cd tolerance of clone T. Overall high Hsp70 levels of clone S did not confer cross tolerance to heat stress, contrary to common expectations. Our results suggest a trade-off between the efforts to limit the proteotoxic symptoms of Cd toxicity by Hsp70 induction and those to sequester and detoxify Cd by

  13. Molecular cloning of manganese superoxide dismutase gene in the cladoceran Daphnia magna: Effects of microcystin, nitrite, and cadmium on gene expression profiles

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Kai; Zhu, Xuexia; Chen, Rui [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China); Chen, Yafen [State Key Laboratory for Lake Science and Environment, Nanjing Institute of Geography and Limnology, the Chinese Academy of Sciences, Nanjing 210008 (China); Yang, Zhou, E-mail: yangzhou@njnu.edu.cn [Jiangsu Key Laboratory for Biodiversity and Biotechnology, School of Biological Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210023 (China)

    2014-03-01

    Graphical abstract: - Highlights: • Daphnia magna MnSOD (Dm-MnSOD) was identified and revealed MnSOD-family features. • The expression of Dm-MnSOD decreased with increased developmental stages. • Dm-MnSOD transcript was kinetically up-regulated by microcystin, nitrite and Cd. • Response of SOD to ubiquitous waterborne pollutants in D. magna was elucidated. • Dm-MnSOD gene is a potential biomarker indicating pollutants in the environment. - Abstract: Superoxide dismutases (SODs) are metalloenzymes that represent one important line of defense against oxidative stress produced by reactive oxygen species in aerobic organisms. Generally, waterborne pollutants caused by irregular anthropogenic activities often result in oxidative damage in aquatic organisms. The aim of this study was to molecularly characterize the manganese superoxide dismutase gene (Dm-MnSOD) in the waterflea, Daphnia magna, and evaluate the mRNA expression patterns quantified by real-time PCR after exposure to three common waterborne pollutants (microcystin-LR, nitrite, and cadmium). The results showed that the full-length Dm-MnSOD sequence consists of 954 bp nucleotides, encoding 215 amino acids, showing well-conserved domains that are required for metal binding and several common characteristics, such as two MnSOD domains. The deduced amino acid sequence of Dm-MnSOD shared over 70% similarity with homologues from Bythograea thermydron, Dromia personata, Cancer pagurus, and Scylla paramamosain. Dm-MnSOD gene expression was up-regulated in response to exposure to the three chemicals tested. The overall results indicated that Dm-MnSOD gene is an inducible gene and potential biomarker indicating these pollutants in the environment.

  14. The influence of natural organic matter and aging on suspension stability in guideline toxicity testing of silver, zinc oxide, and titanium dioxide nanoparticles with Daphnia magna.

    Science.gov (United States)

    Cupi, Denisa; Hartmann, Nanna B; Baun, Anders

    2015-03-01

    The present study investigated changes in suspension stability and ecotoxicity of engineered nanoparticles (ENPs) by addition of Suwannee River natural organic matter and aging of stock and test suspensions prior to testing. Acute toxicity tests of silver (Ag), zinc oxide (ZnO), and titanium dioxide (TiO2 ) ENPs with Daphnia magna were carried out following Organisation for Economic Co-operation and Development test guidelines. Daphnia magna was found to be very sensitive to Ag ENPs (48-h 50% effective concentration 33 μg L(-1) ), and aging of the test suspensions in M7 medium (up to 48 h) did not decrease toxicity significantly. Conversely, the presence of Suwannee River natural organic matter (NOM; 20 mg L(-1) ) completely alleviated Ag ENP toxicity in all testing scenarios and did not aid in stabilizing suspensions. In contrast, addition of Suwannee River NOM stabilized ZnO ENP suspensions and did not decrease toxicity. Aging for 48 h generated monotonous concentration-response curves in the presence and absence of Suwannee River NOM. At concentrations up to 100 mg L(-1) TiO2 ENPs did not cause immobilization of D. magna under any of the tested conditions. Presence of Suwannee River NOM caused agglomeration in stock suspensions. The authors' results suggest that aging and presence of Suwannee River NOM are important parameters in standard toxicity testing of ENPs, which in some cases may aid in gaining better control over the exposure conditions but in other cases might contribute to agglomeration or elimination of ENP toxicity. Therefore, modifications to the current guidelines for testing ENPs should be evaluated on a case-by-case basis. Environ Toxicol Chem 2015;34:497-506. © 2014 SETAC.

  15. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: Implications for regulatory study designs and ecological risk assessments for GM crops

    Science.gov (United States)

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed. PMID:25523175

  16. Exchange of polar lipids from adults to neonates in Daphnia magna: Perturbations in sphingomyelin allocation by dietary lipids and environmental toxicants.

    Science.gov (United States)

    Sengupta, Namrata; Reardon, Delaney C; Gerard, Patrick D; Baldwin, William S

    2017-01-01

    Because xenosensing nuclear receptors are also lipid sensors that regulate lipid allocation, we hypothesized that toxicant-induced modulation of HR96 activity would alter lipid profiles and the balance between adult survival and neonate production following exposure in Daphnia magna. Adult daphnids were exposed to unsaturated fatty acid- and toxicant- activators or inhibitors of HR96 and later starved to test whether chemical exposure altered allocation toward survival or reproduction. The HR96 activators, linoleic acid and atrazine, decreased reproduction as expected with concomitant changes in the expression of HR96 regulated genes such as magro. The HR96 inhibitors, docosahexaenoic acid (DHA) and triclosan, increased reproduction or neonate starvation survival, respectively. However, pre-exposure to triclosan increased in neonate survival at the expense of reproductive maturation. Lipidomic analysis revealed that sphingomyelins (SM) are predominantly found in neonates and therefore we propose are important in development. DHA and triclosan increased neonatal SM, consistent with HR96's regulation of Niemann-Pick genes. While DHA altered expression of magro, Niemann-Pick 1b, mannosidase, and other HR96-regulated genes as expected, triclosan primarily perturbed sphingomyelinase and mannosidase expression indicating different but potentially overlapping mechanisms for perturbing SM. Overall, SM appears to be a key lipid in Daphnia maturation and further support was provided by carmofur, which inhibits sphingomyelin/ceramide metabolism and in turn severely represses Daphnia maturation and initial brood production. In conclusion, toxicants can perturb lipid allocation and in turn impair development and reproduction.

  17. Effects of chronic uranium exposure on life history and physiology of Daphnia magna over three successive generations

    Energy Technology Data Exchange (ETDEWEB)

    Massarin, Sandrine [Laboratoire de Modelisation Environnementale, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Alonzo, Frederic, E-mail: frederic.alonzo@irsn.fr [Laboratoire de Modelisation Environnementale, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Garcia-Sanchez, Laurent [Laboratoire de Modelisation Environnementale, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Gilbin, Rodolphe [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Garnier-Laplace, Jacqueline [Service d' Etude du Comportement des Radionucleides dans les Ecosystemes, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Poggiale, Jean-Christophe [Laboratoire de Microbiologie, Geochimie et Ecologie Marines (UMR CNRS 6117), Centre d' Oceanologie de Marseille, Universite de la Mediterranee, Campus de Luminy, Case 901, Marseille Cedex 9, 13288 (France)

    2010-09-01

    Daphnia magna was exposed to waterborne uranium (U) at concentrations ranging from 10 to 75 {mu}g L{sup -1} over three successive generations (F0, F1 and F2). Progeny was either exposed to the same concentration as mothers to test whether susceptibility to this radioelement might vary across generations or returned to a clean medium to examine their capacity to recover after parental exposure. Maximum body burdens of 17, 32 and 54 ng U daphnid{sup -1} were measured in the different exposure conditions and converted to corresponding internal alpha dose rates. Low values of 5, 12 and 20 {mu}Gy h{sup -1} suggested that radiotoxicity was negligible compared to chemotoxicity. An increasing sensitivity to toxicity was shown across exposed generations with significant effects observed on life history traits and physiology as low as 10 {mu}g L{sup -1} and a capacity to recover partially in a clean medium after parental exposure to {<=}25 {mu}g L{sup -1}. Using a {sup 14}C-labelled food technique, the study showed that uranium affected carbon assimilation in F0 at concentrations of 25 and 75 {mu}g L{sup -1} (34 and 80% reduction respectively) and as low as 10 {mu}g L{sup -1} in F1 and F2 (40 and 36% reduction respectively). Consequences were strong for both somatic growth and reproduction and increased in severity across generations. Maximum size was reduced by 12% at 75 {mu}g L{sup -1} in F0 and 23% at 25 {mu}g L{sup -1} in F2. Reduction in 21-day fecundity ranged from 27 to 48% respectively at 25 and 75 {mu}g L{sup -1} in F0 and from 43 to 71% respectively at 10 and 25 {mu}g L{sup -1} in F2. Growth retardation caused a delay in deposition of first brood of 1.3 days at 75 {mu}g L{sup -1} in F0, of 1.9 days at 25 {mu}g L{sup -1} in F1 and of 5 days at 25 {mu}g L{sup -1} in F2. Differences in respiration rates and egg dry mass between the control and exposed daphnids were mainly an indirect result of uranium effect on body size. The observed increase in toxic effects across

  18. Neverland regulates embryonic moltings through the regulation of ecdysteroid synthesis in the water flea Daphnia magna, and may thus act as a target for chemical disruption of molting.

    Science.gov (United States)

    Sumiya, Eri; Ogino, Yukiko; Toyota, Kenji; Miyakawa, Hitoshi; Miyagawa, Shinichi; Iguchi, Taisen

    2016-11-01

    Embryo development in arthropods is accompanied by a series of moltings. A cladoceran crustacean Daphnia magna molts three times before reaching first instar neonate during embryogenesis. Previous studies argued ecdysteroids might regulate D. magna embryogenesis. However, no direct evidence between innate ecdysteroids fluctuation and functions has been forthcoming. Recently, we identified genes involved in ecdysteroid synthesis called, neverland (neverland1 and neverland 2) and shade and in the ecdysteroid degradation (Cyp18a1). To understand the physiological roles of ecdysteroids in D. magna embryos, we performed expression and functional analyzes of those genes. Examining innate ecdysteroids titer during embryogenesis showed two surges of ecdysteroids titer at 41 and 61 h after oviposition. The first and second embryonic moltings occurred at each ecdysteroid surge. Expression of neverland1 and shade began to increase before the first peak in ecdysteroid. Knockdown of neverland1 or shade by RNAi technique caused defects in embryonic moltings and subsequent development. The ecdysteroids titer seemingly decreased in nvd1-knowckdown embryos. Knockdown of Cyp18a1 resulted in early embryonic lethality before the first molting. Our in situ hybridization analysis revealed that nvd1 was prominently expressed in embryonic gut epithelium suggesting the site for an initial step of ecdysteroidgenesis, a conversion of cholesterol to 7-dehydrocholesterol and possibly for ecdysone production. Taken together, de novo ecdysteroid synthesis by nvd1 in the gut epithelial cells stimulates molting, which is indispensable for D. magna embryo development. These findings identify neverland as a possible target for chemicals, including various pesticides that are known to disrupt molting, development and reproduction. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Measuring internal azole and pyrethroid pesticide concentrations in Daphnia magna using QuEChERS and GC-ECD--method development with a focus on matrix effects.

    Science.gov (United States)

    Kretschmann, Andreas; Cedergreen, Nina; Christensen, Jan H

    2016-02-01

    Pyrethroids are highly toxic towards aquatic macroinvertebrates such as Daphnia magna and can be synergized when co-occurring with azole fungicides. A sensitive analytical method for the measurement of azole-pyrethroid mixtures in aquatic macroinvertebrates is not available at present. We developed and validated an extraction, cleanup, and quantification procedure for four pyrethroid insecticides and four azole fungicides at the picograms per milligram wet weight level in D. magna using a QuEChERS approach and GC-ECD analysis. Short- and long-term matrix effects were analyzed by injection of a series of extracts from D. magna, and the best surrogate standards were identified through correlation analysis of analyte responses. The presence of matrix clearly stabilized the analyte responses (≤6% relative standard deviation of peak area compared to up to 22% when injected without matrix). The sensitivity was high with detection limits and limits of quantification between 58-168 and 119-571 pg mg(wet weight)(-1) for the azoles and 5.8-27 and 12-84 pg mg(wet weight)(-1) for the pyrethroids, respectively. Accuracy (% recovery) was between 95 and 111% and the precision (repeatability) below 10% relative standard deviation for all analytes. In the case of prochloraz, α-cypermethrin, and deltamethrin, normalization to surrogate standards led to a clear improvement of accuracy and precision by up to 8 and 4%, respectively. The method was successfully applied to the measurement of internal α-cypermethrin concentrations in D. magna under environmentally relevant exposure conditions (exposure to a pulse in the micrograms per liter range) with and without co-exposure to propiconazole.

  20. Resurrecting complexity: the interplay of plasticity and rapid evolution in the multiple trait response to strong changes in predation pressure in the water flea Daphnia magna.

    Science.gov (United States)

    Stoks, Robby; Govaert, Lynn; Pauwels, Kevin; Jansen, Bastiaan; De Meester, Luc

    2015-12-09

    A resurrection ecology reconstruction of 14 morphological, life history and behavioural traits revealed that a natural Daphnia magna population rapidly tracked changes in fish predation by integrating phenotypic plasticity and widespread evolutionary changes both in mean trait values and in trait plasticity. Increased fish predation mainly generated rapid adaptive evolution of plasticity (especially in the presence of maladaptive ancestral plasticity) resulting in an important change in the magnitude and direction of the multivariate reaction norm. Subsequent relaxation of the fish predation pressure resulted in reversed phenotypic plasticity and mainly caused evolution of the trait means towards the ancestral pre-fish means. Relaxation from fish predation did, however, not result in a complete reversal to the ancestral fishless multivariate phenotype. Our study emphasises that the study population rapidly tracked environmental changes through a mosaic of plasticity, evolution of trait means and evolution of plasticity to generate integrated phenotypic changes in multiple traits. © 2015 John Wiley & Sons Ltd/CNRS.

  1. [Effect of a model of the H-component of a typical magnetic storm on early ontogenesis in Daphnia magna Straus].

    Science.gov (United States)

    Krylov, V V; Zotov, O D; Osipova, E A; Znobishcheva, A V; Demtsun, N A

    2010-01-01

    The effect of a model of the H-component of a typical magnetic storm on the early ontogenesis of Daphnia magna Straus at 21 and 23 degrees C has been studied. It was shown based on the rates of the early ontogenesis that the effects of the model magnetic storm from the sudden onset of the storm to its end differ from the effects of the model magnetic storm from the recovery phase to the end of the storm. The effects of the model magnetic storm depended on temperature. The action of the model magnetic storm from the sudden onset of the storm to its end led to changes in the body length in the first progeny broods.

  2. Effectiveness of the sulfur(IV) compound, sodium bisulfite, in reducing chlorine, chlorine dioxide, and chlorite toxicity to Daphnia magna in well water and pond water.

    Science.gov (United States)

    Yonkos, L T; Fisher, D J; Burton, D T; Whitekettle, W K; Peterille, J C

    2001-03-01

    Flow-through toxicity tests were conducted with Daphnia magna to determine the residual toxicity of chlorine, chlorine dioxide, and chlorite after treatment with the sulfur(IV) compound sodium bisulfite. Daphnids were exposed separately to 0.5-mg/L concentrations of each of the three compounds without the addition of sodium bisulfite, with a low stoichiometric dose of sodium bisulfite, and with a high stoichiometric dose of sodium bisulfite. Tests were performed in well water with a low total organic carbon (TOC) content and pond water with a high TOC content. Analysis of results indicated that sodium bisulfite did not eliminate the toxicity of chlorine dioxide or chlorite to D. magna. Total residual oxidant (TRO) concentrations were reduced and survival times were extended, but acute toxicity persisted even with a S(IV) concentration 10.0 times the stoichiometric ratio of oxidant. Mortality occurred in chlorine dioxide treatments in which no TRO was detected, indicating that standard analytical (amperometric) techniques may be inadequate to detect toxicity. Sodium bisulfite did succeed in eliminating chlorine toxicity except in pond water receiving a low (3.0x) sodium bisulfite dose. Oxidant reactions with organic substrates may have produced chlorinated residuals that were resistant to S(IV) dechlorination.

  3. QSTR with extended topochemical atom (ETA) indices. 16. Development of predictive classification and regression models for toxicity of ionic liquids towards Daphnia magna.

    Science.gov (United States)

    Roy, Kunal; Das, Rudra Narayan

    2013-06-15

    Ionic liquids have been judged much with respect to their wide applicability than their considerable harmful effects towards the living ecosystem which has been observed in many instances. Hence, toxicological introspection of these chemicals by the development of predictive mathematical models can be of good help. This study presents an attempt to develop predictive classification and regression models correlating the structurally derived chemical information of a group of 62 diverse ionic liquids with their toxicity towards Daphnia magna and their interpretation. We have principally used the extended topochemical atom (ETA) indices along with various topological non-ETA and thermodynamic parameters as independent variables. The developed quantitative models have been subjected to extensive statistical tests employing multiple validation strategies from which acceptable results have been reported. The best models obtained from classification and regression studies captured necessary structural information on lipophilicity, branching pattern, electronegativity and chain length of the cationic substituents for explaining ecotoxicity of ionic liquids towards D. magna. The derived information can be successfully used to design better ionic liquid analogues acquiring the qualities of a true eco-friendly green chemical.

  4. Validation of a Mathematical Model for Green Algae (Raphidocelis Subcapitata Growth and Implications for a Coupled Dynamical System with Daphnia Magna

    Directory of Open Access Journals (Sweden)

    Michael Stemkovski

    2016-05-01

    Full Text Available Toxicity testing in populations probes for responses in demographic variables to anthropogenic or natural chemical changes in the environment. Importantly, these tests are primarily performed on species in isolation of adjacent tropic levels in their ecosystem. The development and validation of coupled species models may aid in predicting adverse outcomes at the ecosystems level. Here, we aim to validate a model for the population dynamics of the green algae Raphidocelis subcapitata, a planktonic species that is often used as a primary food source in toxicity experiments for the fresh water crustacean Daphnia magna. We collected longitudinal data from three replicate population experiments of R. subcapitata. We used this data with statistical model comparison tests and uncertainty quantification techniques to compare the performance of four models: the Logistic model, the Bernoulli model, the Gompertz model, and a discretization of the Logistic model. Overall, our results suggest that the logistic model is the most accurate continuous model for R. subcapitata population growth. We then implement the numerical discretization showing how the continuous logistic model for algae can be coupled to a previously validated discrete-time population model for D. magna.

  5. Effects of stable aqueous fullerene nanocrystal (nC60) on Daphnia magna:Evaluation of hop frequency and accumulations under different conditions

    Institute of Scientific and Technical Information of China (English)

    Xianji Tao; Yiliang He; Bo Zhang; Yongsheng Chen; Joseph B. Hughes

    2011-01-01

    We investigated the effects of environmental factors and properties of water-stable crystal fullerene (nC60) on the uptake of nC60 by Daphnia magna based on known accumulation in our laboratory. This study was performed for seven days using different environmental factors including temperature, pH, water hardness, concentration (density of particle), and particle size. Results demonstrated that body burden of C60 increased with time in all experiments. Body burden of C60 increased with increasing concentration and particle size, and uptake of particles >100 nm reached their maximums more quickly than those <100 nm. Under high hardness in aqueous systems with lower pH and high temperature, uptake was higher than those under opposite conditions. Uptake in all batch tests reached balance within five days. Both nC60 properties and environmental factors influenced uptake of nC60 by D.magna in an aqueous system. Additionally, environmental factors may have affected accumulation by changing nC60 properties, which are critical to understand the accumulation of fullerenes in aqueous systems.

  6. The chronic toxicity of ZnO nanoparticles and ZnCl2 to Daphnia magna and the use of different methods to assess nanoparticle aggregation and dissolution.

    Science.gov (United States)

    Adam, Nathalie; Schmitt, Claudia; Galceran, Josep; Companys, Encarna; Vakurov, Alexander; Wallace, Rachel; Knapen, Dries; Blust, Ronny

    2014-11-01

    In this study, the effect of ZnO nanoparticles and ZnCl2 on growth, reproduction and accumulation of zinc in Daphnia magna was determined in a 21-day chronic toxicity test. A variety of techniques were used to distinguish the free zinc ion, dissolved, nanoparticle and aggregated zinc fraction in the Daphnia test medium. The results showed similar chronic effects on growth, reproduction and accumulation for the ZnO nanoparticles (EC10, 20, 50 reproduction: 0.030, 0.049, 0.112 mg Zn/l) and the ZnCl2 (EC10, 20, 50 reproduction: 0.014, 0.027, 0.082 mg Zn/l). A large fraction of the nanoparticles rapidly dissolved after introduction in the exposure medium. Aggregation of nanoparticles was also observed but within 48 h of exposure most of these ZnO aggregates were dissolved. Based on the combined dissolution kinetics and toxicity results, it can be concluded that the toxicological effects of ZnO nanoparticles at the chronic level can be largely attributed to the dissolved fraction rather than the nanoparticles or initially formed aggregates.

  7. Comparison of R-metalaxyl and rac-metalaxyl in acute, chronic, and sublethal effect on aquatic organisms: Daphnia magna, Scenedesmus quadricanda, and Danio rerio.

    Science.gov (United States)

    Yao, Kun; Zhu, Lin; Duan, Zhenghua; Chen, Zhongzhi; Li, Yan; Zhu, Xiaoshan

    2009-04-01

    Chiral pesticides are used widely in the world, and at present, older racemic products are being replaced by enantiopure products because of accelerated development of asymmetry synthesis techniques. Pesticides as xenobiotic released into environment impose a great stress on nontarget organisms. Although it is a necessary procedure for pesticides to have a registration based on toxicological data from nontarget organism, until now ecological risk assessment about metalaxyl only depend on racemic products. Hence, we investigated the acute, chronic, and sublethal toxicity of R-metalaxy and rac-metalaxyl on aquatic organisms such as D. magna (Daphnia magna), algae (Scenedesmus quadricanda), and adult zebrafish (Danio rerio). The results showed a significant difference in toxicity between R-metalaxyl and rac-metalaxyl. R-Metalaxy was about 20-fold more toxic to algae than rac-metalaxyl with IC(50) of 222.89 +/- 1.18 mg/L and 19.95 +/- 1.12 mg/L, respectively. Similarly, R-metalaxyl was about fourfold toxic to D. magna than rac-metalaxyl according to the individual 24-h-LC(50) values, and sixfold toxic than rac-metalaxyl based on 24-h-EC(50) values. In the light of 48-h-LC(50) and EC(50), this difference in toxicity was more significant. As for adult zebrafish, there was no pronounced difference in acute toxicity, in addition, at sublethal level a different pattern in inducing Na(+),K(+)-ATPase activity between them was found. In general, R-metalaxyl seemed more toxic to aquatic organisms than rac-metalaxyl. Copyright 2008 Wiley Periodicals, Inc.

  8. Toxicokinetic and toxicodynamic model for diazinon toxicity--mechanistic explanation of differences in the sensitivity of Daphnia magna and Gammarus pulex.

    Science.gov (United States)

    Kretschmann, Andreas; Ashauer, Roman; Hollender, Juliane; Escher, Beate I

    2012-09-01

    A mechanistic toxicokinetic and toxicodynamic model for acute toxic effects (immobilization, mortality) of the organothiophosphate insecticide diazinon in Daphnia magna is presented. The model was parameterized using measured external and internal (whole-body) concentrations of diazinon, its toxic metabolite diazoxon, and the inactive metabolite 2-isopropyl-6-methyl-4-pyrimidinol, plus acetylcholinesterase (AChE) activity measured during exposure to diazinon in vivo. The toxicokinetic and toxicodynamic model provides a coherent picture from exposure to the resulting toxic effect on an organism level through internally formed metabolites and the effect on a molecular scale. A very fast reaction of diazoxon with AChE (pseudo first-order inhibition rate constant k(i) = 3.3 h(-1)) compared with a slow formation of diazoxon (activation rate constant k(act) = 0.014 h(-1)) was responsible for the high sensitivity of D. magna toward diazinon. Recovery of AChE activity from inhibition was slow and rate-determining (99% recovery within 16 d), compared with a fast elimination of diazinon (99% elimination within 17 h). The obtained model parameters were compared with toxicokinetic and toxicodynamic parameters of Gammarus pulex exposed to diazinon from previous work. This comparison revealed that G. pulex is less sensitive because of a six times faster detoxification of diazinon and diazoxon and an approximately 400 times lower rate for damage accrual. These differences overcompensate the two times faster activation of diazinon to diazoxon in G. pulex compared to D. magna. The present study substantiates theoretical considerations that mechanistically based effect models are helpful to explain sensitivity differences among different aquatic invertebrates.

  9. Efecto tóxico del DDT, clordano y agua de la presa Ignacio Ramírez (México, sobre Daphnia magna (Crustacea: Daphnidae

    Directory of Open Access Journals (Sweden)

    Laura Martínez-Tabche

    1999-12-01

    Full Text Available Actualmente en México son empleados los plaguicidas diclorodifeniltricloroetano (DDT y clordano (CLO para combatir la malaria y termitas. De 1990 a 1996 un total de 27 ton de DDT y 508 de CLO, en forma de productos técnicos, fueron importados. El objetivo de este estudio fue establecer una metodología para determinar el impacto ambiental que pueden producir estos compuestos sobre un embalse. El efecto tóxico del DDT y CLO fue evaluado sobre la actividad de la o-demetilasa (OD y del acetilcolinesterasa (AchA del cladócero Daphnia magna al exponerla a diferentes concentraciones de los insecticidas disueltos en el agua de tres sitios de la presa Ignacio Ramírez (PIR. El efecto del agua contaminada con los insecticidas sobre la actividad de la AChA y OD, así como la CL50, fueron utilizadas como indicadores de exposición para determinar los lugares más contaminadas de la PIR. Las características fisicoquímicas del agua así como la biodiversidad de los sitios en estudio de la presa fueron considerados. Los resultados obtenidos demuestran que la estación cercana a la compuerta exhibe un potencial de toxicidad, ya que las actividades enzimáticas fueron modificadas. Se sugiere utilizar las actividades de AchA y OD del cladócero para evaluar la toxicidad de un cuerpo de agua contaminado por insecticidas organoclorados.Chlorodiphenylnitrichloroethane (DDT and chlordane (CLO are currently used in Mexico to control malaria and termites. From 1990 to 1996 a total of 27 ton of DDT and 508 of CLO were imported. We establish a methodology to determine their environmental impact in a Mexican dam (Ignacio Ramírez. The toxic effect of DDT and CLO were evaluated on the o-demethylase (OD and acethycholinesterase activities (AchA of the cladoceran Daphnia magna exposed to different concentrations of the insecticides solved in water from three sites. Their effect on the AchA and OD activities, and so the CL50 were used as exposure bioindicators to

  10. Acute toxicity of nano-ZnO to Daphnia Magna%纳米ZnO对大型潘的急性毒性效应研究

    Institute of Scientific and Technical Information of China (English)

    宋文华; 刘艳; 高敏苓; 张文佳; 张金洋

    2009-01-01

    The ecotoxieity of nanoscale ZnO water suspensions for Daphnia magna was used as the testing organisms under both conditions of natural light and darkness was examined using a method developed based on the standard OECD guide-lines for the testing of chemicals (i. e. OECD 201,202). The results showed that different nanoscale ZnO exhibited differ-ent toxieities to the testing organisms. The EC50 of (10±1), (25±5) and (90±10) nm ZnO were 12.21, 9.96 and 167.36 mg/L in 48 hours under the natural light, respectively. Based on the results, their toxicity ranked as (25 ± 5),(10±1)>(904±10) nm. The EC50 of (10±1), (25±5) and (90±10) nm ZnO were 19.64,206. 70 and 409. 84 mg/L in 48 hours under the darkness, respectively. The toxicity results indicated that nanoscale ZnO was more danger to daphnia magna in natural light than that of in darkness, and the toxicity was affected by nanopartiele size.%以大型溞为模式生物,研究了自然光照(光暗比为12 h:12 h)和黑暗条件下纳米ZnO对水生生物的急性毒性效应.实验结果表明,在自然光照条件下,不同粒径纳米ZnO对大型溞的毒性顺序为(25±5)和(10±1)>(90±10)nm,其EC50分别为12.21,9.96和167.36 mg/L;黑暗条件下,(10±1),(25±5)和(90±10)am ZnO时大型溞抑制的EC50分别为19.64,206.70和409.84 mg/L.由此可以看出,纳米ZnO在光照条件下对大型溞的影响大于黑暗条件,且粒径大小影响其毒性强弱.

  11. Comparison of the sensitivities of fish, Microtox and Daphnia-magna bioassays to amoxycillin in anaerobic/aerobic sequential reactor systems.

    Science.gov (United States)

    Çelebi, H; Sponza, D T

    2012-01-01

    In this study the anaerobic treatability of amoxycillin (AMX) was investigated in a laboratory-scale anaerobic multi-chamber bed reactor (AMCBR)/aerobic continuously stirred tank reactor (CSTR) system. The chemical oxygen demand (COD) and AMX removal efficiencies were around 94% in the AMCBR reactor at hydraulic retention times (HRTs) between 2.25 and 5.5 days. Decreasing the HRT appeared not to have a significant effect on the performance of the AMCBR up to a HRT of 1.13 days. The maximum methane production rate and methane percentage were around 1,100-1,200 mL/day and 55%, respectively, at HRTs between 2.25 and 5.5 days. The decrease in HRT to 1.5 days decreased slightly the gas productions (1,000 mL/day and 500 mL for total and methane gases) and methane percentage (45%). The AMCBR recovered back to its baseline performance within a couple of days. The acute toxicity of 150 mg/L AMX was monitored with Daphnia magna, Lepistes sp., and Vibrio fischeri acute toxicity tests. The acute toxicity removals were 98, 96 and 96% for V. fischeri, D. magna and Lepistes sp. in the effluent of the sequential system treating 150 mg/L AMX at HRTs of 2.25-5.5 days. Among the trophic organisms used in the acute toxicity tests the most sensitive organism was found to be bacteria (V. fischeri) while the most resistant organism was found to be fish (Lepistes sp.).

  12. The genetic basis of resistance and matching-allele interactions of a host-parasite system: The Daphnia magna-Pasteuria ramosa model.

    Science.gov (United States)

    Bento, Gilberto; Routtu, Jarkko; Fields, Peter D; Bourgeois, Yann; Du Pasquier, Louis; Ebert, Dieter

    2017-02-01

    Negative frequency-dependent selection (NFDS) is an evolutionary mechanism suggested to govern host-parasite coevolution and the maintenance of genetic diversity at host resistance loci, such as the vertebrate MHC and R-genes in plants. Matching-allele interactions of hosts and parasites that prevent the emergence of host and parasite genotypes that are universally resistant and infective are a genetic mechanism predicted to underpin NFDS. The underlying genetics of matching-allele interactions are unknown even in host-parasite systems with empirical support for coevolution by NFDS, as is the case for the planktonic crustacean Daphnia magna and the bacterial pathogen Pasteuria ramosa. We fine-map one locus associated with D. magna resistance to P. ramosa and genetically characterize two haplotypes of the Pasteuria resistance (PR-) locus using de novo genome and transcriptome sequencing. Sequence comparison of PR-locus haplotypes finds dramatic structural polymorphisms between PR-locus haplotypes including a large portion of each haplotype being composed of non-homologous sequences resulting in haplotypes differing in size by 66 kb. The high divergence of PR-locus haplotypes suggest a history of multiple, diverse and repeated instances of structural mutation events and restricted recombination. Annotation of the haplotypes reveals striking differences in gene content. In particular, a group of glycosyltransferase genes that is present in the susceptible but absent in the resistant haplotype. Moreover, in natural populations, we find that the PR-locus polymorphism is associated with variation in resistance to different P. ramosa genotypes, pointing to the PR-locus polymorphism as being responsible for the matching-allele interactions that have been previously described for this system. Our results conclusively identify a genetic basis for the matching-allele interaction observed in a coevolving host-parasite system and provide a first insight into its molecular basis.

  13. Effects of dietary exposure to herbicide and of the nutritive quality of contaminated food on the reproductive output of Daphnia magna.

    Science.gov (United States)

    Bessa da Silva, M; Abrantes, N; Rocha-Santos, T A P; Duarte, A C; Freitas, A C; Gomes, A M; Carvalho, A P; Marques, J C; Gonçalves, F; Pereira, R

    2016-10-01

    Risk assessment of pesticides has been based on direct toxic effects on aquatic organisms. Indirect effects data are taken into account but with limitations, as it is frequently difficult to predict their real impacts in the ecosystems. In this context the main aim of this work was to assess how the exposure to the herbicide pendimethalin (Prowl(®)), under environmentally relevant concentrations, may compromise the nutritional composition of food for a relevant group of primary consumers of freshwater food webs-the daphnids, thus affecting their reproduction performance and subsequently the long-term sustainability of active populations of this grazer. Therefore, Daphnia magna individuals were chronically exposed in a clean medium to a control diet (NCF - i.e., non-contaminated green algae Raphidocelis subcapitata) and to a contaminated diet (CF - i.e., the same monoalgal culture grown in a medium enriched with pendimethalin in a concentration equivalent to the EC20 for growth inhibition of algae), during which reproductive endpoints were assessed. The algae were analysed for protein, carbohydrate and fatty acid content. The chemical composition of R. subcapitata in the CF revealed a slight decrease on total fatty acid levels, with a particular decrease of essential ω9 monounsaturated fatty acids. In contrast, the protein content was high in the CF. D. magna exposed to CF experienced a 16% reduction in reproduction, measured as the total number of offspring produced per female. Additionally, an internal pendimethalin body burden of 4.226μgg(-1) was accumulated by daphnids fed with CF. Hence, although it is difficult to discriminate the contribution of the pesticide (as a toxic agent transferred through the food web) from that of the food with a poor quality-compromised by the same pesticide, there are no doubts that, under environmentally relevant concentrations of pesticides, both pathways may compromise the populations of freshwater grazers in the long term

  14. Acute toxicity over Ceriodaphnia silvestrii and Daphnia magna: Bioassays with water samples from a dam under the influence of uranium mine and with manganese

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Carla R.; Nascimento, Heliana de Azevedo Franco do; Silverio, Emilia Gabriela Costa; Bruschi, Armando Luis; Roque, Claudio Vitor; Nascimento, Marcos Roberto L.; Bonifacio, Rodrigo Leandro, E-mail: carlarolimferrari@yahoo.com.br, E-mail: hazevedo@cnen.gov.br, E-mail: emiliagcsilverio@hotmail.com, E-mail: abruschi@cnen.gov.br, E-mail: cvroque@cnen.gov.br, E-mail: pmarcos@cnen.gov.br, E-mail: rodrigo@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Rodgher, Suzelei [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Jose dos Campos, SP (Brazil). Dep. de Engenharia Ambiental

    2015-07-01

    Treated effluents from uranium mine with acid mine drainage can impact receiving water bodies. AMD is relevant from the environmental view due to the large volume of effluents generated, known to affect aquatic biota. Studies show that one of the main problems of treated effluents released by UTM/INB on the catchment basin of Ribeirao das Antas is associated to high Mn values in water samples. In this context, acute 48-h toxicity tests with Mn were conducted with Ceriodaphnia silvestrii and Daphnia magna to determine the No Observed Effect Concentration (NOEC) and the Observed Effect Concentration (OEC) in laboratory bioassays and to verify the potential toxicity of the Mn in face of concentrations found in water samples from the Antas Dam, which receives treated effluents from UTM/INB. In this study, preliminary results of acute toxicity for C. silvestrii indicated OEC values between 9.0 and 10.0 mg Mn/L and NOEC < 3.0 mg Mn/L. For D. magna, OEC and NOEC concentrations were ≥ 30 mg Mn/L and ≤ 80 mg Mn/L, respectively. It was verified that Mn concentrations determined in environmental samples registered the highest value at 1.75 mg Mn/L, below the OEC concentrations recorded for both species. Since manganese occurs in the composition of the effluent that may contain other stable and radioactive elements, complementary ecotoxicological tests must be conducted, aiming at the assessment of synergistic and antagonistic effects of the chemical mixture that makes up the radioactive effluents that are treated and released at the Antas Dam. Such bioassays are underway in the Radioecology Laboratory at LAPOC/CNEN. (author)

  15. Influence of pH and media composition on suspension stability of silver, zinc oxide, and titanium dioxide nanoparticles and immobilization of Daphnia magna under guideline testing conditions.

    Science.gov (United States)

    Cupi, Denisa; Hartmann, Nanna B; Baun, Anders

    2016-05-01

    In aquatic toxicity testing of engineered nanoparticles (ENPs) the process of agglomeration is very important as it may alter bioavailability and toxicity. In the present study, we aimed to identify test conditions that are favorable for maintaining stable ENP suspensions. We evaluated the influence of key environmental parameters: pH (2-12) and ionic strength using M7, Soft EPA (S EPA) medium, and Very Soft EPA (VS EPA) medium; and observed the influence of these parameters on zeta potential, zeta average, and acute immobilization of Daphnia magna for three different ENPs. Despite being sterically stabilized, test suspensions of silver (Ag) ENPs formed large agglomerates in both VS EPA and M7 media; and toxicity was found to be higher in VS EPA medium due to increased dissolution. Low-agglomerate suspensions for zinc oxide (ZnO) could be obtained at pH 7 in VS EPA medium, but the increase in dissolution caused higher toxicity than in M7 medium. Titanium dioxide (TiO2) ENPs had a point of zero charge in the range of pH 7-8. At pH 7 in VS EPA, agglomerates with smaller hydrodynamic diameters (~200nm) were present compared to the high ionic strength M7 medium where hydrodynamic diameters reached micrometer range. The stable suspensions of TiO2 ENPs caused immobilization of D. magna, 48-h EC50 value of 13.7mgL(-1) (95% CI, 2.4mg-79.1mgL(-1)); whereas no toxicity was seen in the unstable, highly agglomerated M7 medium suspensions, 48-h EC50 >100mgL(-1). The current study provides a preliminary approach for methodology in testing and assessing stability and toxicity of ENPs in aquatic toxicity tests of regulatory relevance.

  16. The genetic basis of resistance and matching-allele interactions of a host-parasite system: The Daphnia magna-Pasteuria ramosa model

    Science.gov (United States)

    Fields, Peter D.; Bourgeois, Yann; Du Pasquier, Louis; Ebert, Dieter

    2017-01-01

    Negative frequency-dependent selection (NFDS) is an evolutionary mechanism suggested to govern host-parasite coevolution and the maintenance of genetic diversity at host resistance loci, such as the vertebrate MHC and R-genes in plants. Matching-allele interactions of hosts and parasites that prevent the emergence of host and parasite genotypes that are universally resistant and infective are a genetic mechanism predicted to underpin NFDS. The underlying genetics of matching-allele interactions are unknown even in host-parasite systems with empirical support for coevolution by NFDS, as is the case for the planktonic crustacean Daphnia magna and the bacterial pathogen Pasteuria ramosa. We fine-map one locus associated with D. magna resistance to P. ramosa and genetically characterize two haplotypes of the Pasteuria resistance (PR-) locus using de novo genome and transcriptome sequencing. Sequence comparison of PR-locus haplotypes finds dramatic structural polymorphisms between PR-locus haplotypes including a large portion of each haplotype being composed of non-homologous sequences resulting in haplotypes differing in size by 66 kb. The high divergence of PR-locus haplotypes suggest a history of multiple, diverse and repeated instances of structural mutation events and restricted recombination. Annotation of the haplotypes reveals striking differences in gene content. In particular, a group of glycosyltransferase genes that is present in the susceptible but absent in the resistant haplotype. Moreover, in natural populations, we find that the PR-locus polymorphism is associated with variation in resistance to different P. ramosa genotypes, pointing to the PR-locus polymorphism as being responsible for the matching-allele interactions that have been previously described for this system. Our results conclusively identify a genetic basis for the matching-allele interaction observed in a coevolving host-parasite system and provide a first insight into its molecular basis

  17. Effect of Na, Ca and pH on simultaneous uptake of Cd, Cu, Ni, Pb, and Zn in the water flea Daphnia magna measured using stable isotopes.

    Science.gov (United States)

    Komjarova, I; Blust, R

    2009-08-31

    The present study investigates the effects of Na(+), Ca(2+) and pH on the kinetics of Cd, Cu, Ni, Pb, and Zn uptake in Daphnia magna at low exposure concentrations measured using a stable isotope technique. Using experimental data the uptake rate constants were calculated for each metal individually on the basis of total metal concentrations. The copper uptake was not significantly affected by variations in chemical composition of the test medium. Calcium had a suppressing effect on the uptake of Cd, Ni, Pb and Zn. Specifically, Cd and Ni uptake rate constants decreased with increases in calcium concentrations from 0.1 to 2.5mM. The uptake of Zn and Pb was significantly suppressed only at 2.5mM Ca. The effect of sodium was less clear. There was no effect of varying sodium concentrations on the Ni uptake rate constants. Cd and Pb showed an increase in uptake rate constants at elevated sodium concentrations (2-8mM Na(+) for Cd and 8mM Na(+) for Pb). A bell-shaped response on increasing Na(+) concentrations was observed for Zn with a maximum value of uptake rate constant at the middle value (2mM Na(+)). Variation in pH of the medium affected Cd, Ni and Zn uptake processes. When Daphnia were exposed to acidic conditions (pH 6), the Cd and Ni uptake rate constants were the highest, while similarly low values were observed at neutral and basic conditions. In contrast, the uptake rates of Zn were linearly increasing with increasing pH of the medium.

  18. Rheoceptive mediators of graviperception in a water flea: Morphological implications of antennal-socket setae in daphnia magna

    Science.gov (United States)

    Meyers, D. G.

    1984-01-01

    Aquatic microcrustaceans of the genus Daphnia are known to orient to light during the day. At night, in the absence of visual cues, daphnids were suspected of maintaining equilibrium by monitoring the direction of gravity through their swimming antennae. Recent investigations using simulated, weightlessness conditions coupled with absence of illumination revealed hair like structures or setae on the basal, articulating socket of the antennae that, when surgically removed, resulted in disorientation. Given the simulated weightlessness or neutrally buoyant condition that eliminated sinking of the normally negatively buoyant Daphnia, it was proposed that the antennal socket setae function as rheoceptors stimulated by the upward rush of water currents during gravity induced, sinking phase of daphnid swimming movements. This rheoceptively mediated, gravity perception hypothesis is further supported by morphological investigations. Scanning electron micrographs indicate that antennal socket setae are anatomically similar to proprioceptors used by higher crustaceans to monitor gravitational direction.

  19. Toxicity of a binary mixture on Daphnia magna: biological effects of uranium and selenium isolated and in mixture; Toxicite d'un melange binaire sur la daphnie Daphnia magna: etude des effets biologiques de l'uranium et du selenium seuls et en melange

    Energy Technology Data Exchange (ETDEWEB)

    Zeman, F.

    2008-10-15

    Among the multiple substances that affect freshwater ecosystems, uranium and selenium are two pollutants found worldwide in the environment, alone and in mixture. The aim of this thesis work was to investigate the effect of uranium and selenium mixture on daphnia (Daphnia magna). Studying effects of a mixture requires the assessment of the effect of single substances. Thus, the first experiments were performed on single substance. Acute toxicity data were obtained: EC{sub 50} 48h = 0, 39{+-}0, 04 mg.L{sup -1} for uranium and EC{sub 50} 48h 1, 86{+-}0, 85 mg.L{sup -1} for selenium. Chronic effects were also studied. Data on fecundity showed an EC{sub 10} reproduction of 14{+-}7 {mu}g. L{sup -1} for uranium and of 215{+-}25 {mu}g. L{sup -1} for selenium. Uranium-selenium mixture toxicity experiments were performed and revealed an antagonistic effect. This study further demonstrates the importance of taking into consideration different elements in binary mixture studies such as the choice of reference models (concentration addition or independent action), statistical method, time exposure and endpoints. Using integrated parameters like energy budget was shown to be an interesting way to better understand interactions. An approach including calculation of chemical speciation in the medium and bioaccumulation measurements in the organism permits assumptions to be made on the nature of possible interactions between mixture components (toxico-dynamic et toxico-kinetic interactions). (author)

  20. Not all that glitters is gold-Electron microscopy study on uptake of gold nanoparticles in Daphnia magna and related artifacts.

    Science.gov (United States)

    Jensen, Louise Helene Søgaard; Skjolding, Lars Michael; Thit, Amalie; Sørensen, Sara Nørgaard; Købler, Carsten; Mølhave, Kristian; Baun, Anders

    2017-06-01

    Increasing use of engineered nanoparticles has led to extensive research into their potential hazards to the environment and human health. Cellular uptake from the gut is sparsely investigated, and microscopy techniques applied for uptake studies can result in misinterpretations. Various microscopy techniques were used to investigate internalization of 10-nm gold nanoparticles in Daphnia magna gut lumen and gut epithelial cells following 24-h exposure and outline potential artifacts (i.e., high-contrast precipitates from sample preparation related to these techniques). Light sheet microscopy confirmed accumulation of gold nanoparticles in the gut lumen. Scanning transmission electron microscopy and elemental analysis revealed gold nanoparticles attached to the microvilli of gut cells. Interestingly, the peritrophic membrane appeared to act as a semipermeable barrier between the lumen and the gut epithelium, permitting only single particles through. Structures resembling nanoparticles were also observed inside gut cells. Elemental analysis could not verify these to be gold, and they were likely artifacts from the preparation, such as osmium and iron. Importantly, gold nanoparticles were found inside holocrine cells with disrupted membranes. Thus, false-positive observations of nanoparticle internalization may result from either preparation artifacts or mistaking disrupted cells for intact cells. These findings emphasize the importance of cell integrity and combining elemental analysis with the localization of internalized nanoparticles using transmission electron microscopy. Environ Toxicol Chem 2017;36:1503-1509. © 2016 SETAC. © 2016 SETAC.

  1. Sublethal and Reproductive Effects of Acute and Chronic Exposure to Flowback and Produced Water from Hydraulic Fracturing on the Water Flea Daphnia magna.

    Science.gov (United States)

    Blewett, Tamzin A; Delompré, Perrine L M; He, Yuhe; Folkerts, Erik J; Flynn, Shannon L; Alessi, Daniel S; Goss, Greg G

    2017-02-13

    Hydraulic fracturing is an industrial process allowing for the extraction of gas or oil. To fracture the rocks, a proprietary mix of chemicals is injected under high pressure, which later returns to the surface as flowback and produced water (FPW). FPW is a complex chemical mixture consisting of trace metals, organic compounds, and often, high levels of salts. FPW toxicity to the model freshwater crustacean Daphnia magna was characterized utilizing acute (48 h median lethal concentrations; LC50) and chronic (21 day) exposures. A decrease in reproduction was observed, with a mean value of 18.5 neonates produced per replicate over a 21 day chronic exposure to 0.04% FPW, which was a significant decrease from the average of 64 neonates produced in the controls. The time to first brood was delayed in the highest FPW (0.04%) treatment. Neonates exhibited an LC50 of 0.19% of full-strength FPW, making them more sensitive than adults, which displayed an LC50 value of 0.75%. Quantitative PCR highlighted significant changes in expression of genes encoding xenobiotic metabolism (cyp4) and moulting (cut). This study is the first to characterize chronic FPW toxicity and will help with the development of environmental monitoring and risk assessment of FPW spills.

  2. Pesticide exposure impacts not only hatching of dormant eggs, but also hatchling survival and performance in the water flea Daphnia magna.

    Science.gov (United States)

    Navis, Sabine; Waterkeyn, Aline; Voet, Tom; De Meester, Luc; Brendonck, Luc

    2013-07-01

    Laboratory ecotoxicity tests and biomonitoring in aquatic systems are currently based on the active component of invertebrate communities. Even though dormant egg banks are crucial for the long term survival and community dynamics of many aquatic organisms, the effects of anthropogenic activities on dormant egg bank dynamics have rarely been studied. In this study we investigated the effects of two pesticides with a different mode of action (carbaryl and fenoxycarb) on hatching of Daphnia magna dormant eggs (ephippia) as well as on survival, growth and reproduction of the hatched neonates. Dormant eggs were exposed to the pesticides simultaneously to incubation under conditions that induce hatching (long daylight and 20 °C). Carbaryl had no negative effects on embryonic development or hatching rate up to concentrations almost 1,000 times the median effect concentration (EC50) of neonate survival in acute tests. Fenoxycarb, however, had a significant dose-related effect by delaying or completely stopping the hatching process and caused severe abnormalities in developing individuals. Both pesticides had significant negative effects on survival and reproduction of the hatchlings. These results indicate that, in addition to inducing mortality of active individuals, pesticides can affect zooplankton communities by altering hatching dynamics and life history traits of hatched individuals. We briefly discuss how such pollution induced changes in the benthic-pelagic coupling could translate into trans-generational effects impacting ecological and evolutionary dynamics.

  3. Development of a regression model to predict copper toxicity to Daphnia magna and site-specific copper criteria across multiple surface-water drainages in an arid landscape.

    Science.gov (United States)

    Fulton, Barry A; Meyer, Joseph S

    2014-08-01

    The water effect ratio (WER) procedure developed by the US Environmental Protection Agency is commonly used to derive site-specific criteria for point-source metal discharges into perennial waters. However, experience is limited with this method in the ephemeral and intermittent systems typical of arid climates. The present study presents a regression model to develop WER-based site-specific criteria for a network of ephemeral and intermittent streams influenced by nonpoint sources of Cu in the southwestern United States. Acute (48-h) Cu toxicity tests were performed concurrently with Daphnia magna in site water samples and hardness-matched laboratory waters. Median effect concentrations (EC50s) for Cu in site water samples (n=17) varied by more than 12-fold, and the range of calculated WER values was similar. Statistically significant (α=0.05) univariate predictors of site-specific Cu toxicity included (in sequence of decreasing significance) dissolved organic carbon (DOC), hardness/alkalinity ratio, alkalinity, K, and total dissolved solids. A multiple-regression model developed from a combination of DOC and alkalinity explained 85% of the toxicity variability in site water samples, providing a strong predictive tool that can be used in the WER framework when site-specific criteria values are derived. The biotic ligand model (BLM) underpredicted toxicity in site waters by more than 2-fold. Adjustments to the default BLM parameters improved the model's performance but did not provide a better predictive tool compared with the regression model developed from DOC and alkalinity.

  4. Estimation of the toxicity of sulfadiazine to Daphnia magna using negligible depletion hollow-fiber liquid-phase microextraction independent of ambient pH

    Science.gov (United States)

    Liu, Kailin; Xu, Shiji; Zhang, Minghuan; Kou, Yahong; Zhou, Xiaomao; Luo, Kun; Hu, Lifeng; Liu, Xiangying; Liu, Min; Bai, Lianyang

    2016-12-01

    The toxicity of ionizable organic compounds to organisms depends on the pH, which therefore affects risk assessments of these compounds. However, there is not a direct chemical method to predict the toxicity of ionizable organic compounds. To determine whether hollow-fiber liquid-phase microextraction (HF-LPME) is applicable for this purpose, a three-phase HF-LPME was used to measure sulfadiazine and estimate its toxicity to Daphnia magna in solutions of different pH. The result indicated that the sulfadiazine concentrations measured by HF-LPME decreased with increasing pH, which is consistent with the decreased toxicity. The concentration immobilize 50% of the daphnids (EC50) in 48 h calculated from nominal concentrations increased from 11.93 to 273.5 mg L-1 as the pH increased from 6.0 to 8.5, and the coefficient of variation (CV) of the EC50 values reached 104.6%. When calculated from the concentrations measured by HF-LPME (pH 12 acceptor phase), the EC50 ranged from 223.4 to 394.6 mg L-1, and the CV decreased to 27.60%, suggesting that the concentrations measured by HF-LPME can be used to estimate the toxicity of sulfadiazine irrespective of the solution pH.

  5. Suspended C{sub 60} nanoparticles protect against short-term UV and fluoranthene photo-induced toxicity, but cause long-term cellular damage in Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.Y. [Department of Zoology, Miami University, Oxford, OH 45056 (United States); Edelmann, R.E. [Electron Microscopy Facility, Miami University, Oxford, OH 45056 (United States); Oris, J.T., E-mail: orisjt@muohio.edu [Department of Zoology, Miami University, Oxford, OH 45056 (United States)

    2010-10-15

    The increased production of nanotechnology materials is a potential source of nano-sized particles (NSPs) in aquatic ecosystems. Meanwhile, polycyclic aromatic hydrocarbons (PAHs), in the presence of ecologically relevant levels of ultraviolet radiation (UV), can be acutely toxic to aquatic species including fish and invertebrates. Considering that suspended carbon-based NSPs (e.g., C{sub 60} fullerenes) may act in similar ways as dissolved organic matter (DOM) by altering the bioavailability of PAHs, the objective of this research was to determine the effect of suspended C{sub 60} on the photo-induced toxicity of fluoranthene. Transmission electron microscopy indicated that the presence of C{sub 60} protected cellular components (e.g., mitochondria, microvilli, and basal infoldings) in organisms exposed to UV and fluoranthene phototoxicity in short-term exposures. However, we found that long-term exposure (21 d) of low-level C{sub 60} caused significant cellular damage in the Daphnia magna alimentary canal. This paper highlights the importance of examining the interactions between existing stressors and nanoparticles in the aquatic environment.

  6. Changes in phototactic behavior of Daphnia magna clone C1242 in response to copper, cadmium and pentachlorophenol

    Institute of Scientific and Technical Information of China (English)

    YUAN Ling; E. Michels; L. De Meester

    2003-01-01

    In order to develop a round biotechnique for monitoring water quality that builds on the previous experiments carried out in our laboratory, a specific D. magna clone C1 242 was used to study the effects of pollutants on phototactic behavior. In all experiments, the animals showed a stable and repeatable phototactic index approximated 0.2 in the presence and 0.4 in the absence of fish kairomones, which decreased significantly in response to pollutants. There existed no pollutant × fish kairomone interaction, indicating the changes in phototactic behavior of animals imposed by pollutants were independent of the presence of fish kairomones. The detection limits for changes in phototactic behavior of D. mgna clone C1242 are 0.04 mg/L for copper, 0.02 mg/L for cadmium, and 0.80 mg/L for PCP, respectively, quite lower than LC50 (48 h). The changes in phototactic behavior in presence to pollutants occurred quickly(3 h) compared to the period over whole acute toxicity tests. Therefore, D. magna clone C1242 could be potentially used to monitor water quality. Moreover, the phototactic behavior did not decrease further in the pollutant mixtures employed in our experiments compared to individual pollutants, except in the Cd-PCP treatment.This fact suggests that the formation of water quality criteria must be based upon pollutant mixture tests.

  7. Environmental Sex Determination in the Branchiopod Crustacean Daphnia magna: Deep Conservation of a Doublesex Gene in the Sex-Determining Pathway

    Science.gov (United States)

    Kato, Yasuhiko; Kobayashi, Kaoru; Watanabe, Hajime; Iguchi, Taisen

    2011-01-01

    Sex-determining mechanisms are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. In contrast to genetic sex determination (GSD), little is known about the molecular mechanisms underlying environmental sex determination (ESD). The Doublesex (Dsx) genes play an important role in controlling sexual dimorphism in genetic sex-determining organisms such as nematodes, insects, and vertebrates. Here we report the identification of two Dsx genes from Daphnia magna, a freshwater branchiopod crustacean that parthenogenetically produces males in response to environmental cues. One of these genes, designated DapmaDsx1, is responsible for the male trait development when expressed during environmental sex determination. The domain organization of DapmaDsx1 was similar to that of Dsx from insects, which are thought to be the sister group of branchiopod crustaceans. Intriguingly, the molecular basis for sexually dimorphic expression of DapmaDsx1 is different from that of insects. Rather than being regulated sex-specifically at the level of pre–mRNA splicing in the coding region, DapmaDsx1 exhibits sexually dimorphic differences in the abundance of its transcripts. During embryogenesis, expression of DapmaDsx1 was increased only in males and its transcripts were primarily detected in male-specific structures. Knock-down of DapmaDsx1 in male embryos resulted in the production of female traits including ovarian maturation, whereas ectopic expression of DapmaDsx1 in female embryos resulted in the development of male-like phenotypes. Expression patterns of another D. magna Dsx gene, DapmaDsx2, were similar to those of DapmaDsx1, but silencing and overexpression of this gene did not induce any clear phenotypic changes. These results establish DapmaDsx1 as a key regulator of the male phenotype. Our findings reveal how ESD is implemented by selective expression of a fundamental genetic component that is functionally conserved

  8. Toxicity of cobalt-complexed cyanide to Oncorhynchus mykiss, Daphnia magna, and Ceriodaphnia dubia: Potentiation by ultraviolet radiation and attenuation by dissolved organic carbon and adaptive UV tolerance

    Science.gov (United States)

    Little, Edward E.; Calfee, Robin D.; Theodorakos, Peter M.; Brown, Zoe Ann; Johnson, Craig A.

    2007-01-01

    BackgroundCobalt cyanide complexes often result when ore is treated with cyanide solutions to extract gold and other metals. These have recently been discovered in low but significant concentrations in effluents from gold leach operations. This study was conducted to determine the potential toxicity of cobalt-cyanide complexes to freshwater organisms and the extent to which ultraviolet radiation (UV) potentiates this toxicity. Tests were also conducted to determine if humic acids or if adaptation to UV influenced sensitivity to the cyanide complexes.MethodsRainbow trout (Oncorhynchus mykiss), Daphnia magna, and Ceriodaphnia dubia were exposed to potassium hexacyanocobaltate in the presence and absence of UV radiation, in the presence and absence of humic acids. Cyano-cobalt exposures were also conducted with C. dubia from cultures adapted to elevated UV.ResultsWith an LC50 concentration of 0.38 mg/L, cyanocobalt was over a 1000 times more toxic to rainbow trout in the presence of UV at a low, environmentally relevant irradiance level (4 μW/cm2 as UVB) than exposure to this compound in the absence of UV with an LC50 of 112.9 mg/L. Toxicity was immediately apparent, with mortality occurring within an hour of the onset of exposure at the highest concentration. Fish were unaffected by exposure to UV alone. Weak-acid dissociable cyanide concentrations were observed in irradiated aqueous solutions of cyanocobaltate within hours of UV exposure and persisted in the presence of UV for at least 96 hours, whereas negligible concentrations were observed in the absence of UV. The presence of humic acids significantly diminished cyanocobalt toxicity to D. magna and reduced mortality from UV exposure. Humic acids did not significantly influence survival among C. dubia. C. dubia from UV-adapted populations were less sensitive to metallocyanide compounds than organisms from unadapted populations.ConclusionsThe results indicate that metallocyanide complexes may pose a hazard to

  9. An investigation of the inter-clonal variation of the interactive effects of cadmium and Microcystis aeruginosa on the reproductive performance of Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    De Coninck, Dieter I.M., E-mail: Dieter.DeConinck@UGent.be; Janssen, Colin R.; De Schamphelaere, Karel A.C.

    2013-09-15

    Highlights: •Interaction of a metal and cyanobacterium in 20 genetically distinct waterflea clones. •All observed effects were non-interactive. •This contrasted expectations based on shared modes of toxic action. -- Abstract: Interactive effects between chemical and natural stressors as well as genetically determined variation in stress tolerance among individuals may complicate risk assessment and management of chemical pollutants in natural ecosystems. Although genetic variation in tolerance to single stressors has been described extensively, genetic variation in interactive effects between two stressors has only rarely been investigated. Here, we examined the interactive effects between a chemical stressor (Cd) and a natural stressor (the cyanobacteria Microcystis aeruginosa) on the reproduction of Daphnia magna in 20 genetically different clones using a full-factorial experimental design and with the independent action model of joint stressor action as the reference theoretical framework. Across all clones, the reduction of 21-day reproduction compared to the control treatment (no Cd, no M. aeruginosa) ranged from −10% to 98% following Cd exposure alone, from 44% to 89% for Microcystis exposure alone, and from 61% to 98% after exposure to Cd + Microcystis combined. Three-way ANOVA on log-transformed reproduction data of all clones together did not detect a statistically significant Cd × Microcystis interaction term (F-test, p = 0.11), meaning that on average both stressors do not interact in inhibiting reproductive performance of D. magna. This finding contrasted expectations based on some known shared mechanisms of toxicity of Cd and Microcystis and therefore cautions against making predictions of interactive chemical + natural stressor effects from incomplete knowledge on affected biological processes and pathways. Further, still based on three-way ANOVA, we did not find statistically significant clone × Cd × Microcystis interaction when data for

  10. Effects of fasting time on food selectivity of water fleas Daphnia magna%饥饿时间对大型溞摄食行为的影响

    Institute of Scientific and Technical Information of China (English)

    刘玮; 杜蓓蓓; 刘钢; 殷旭旺

    2014-01-01

    In the present work we evaluated the influence of fasting time on foraging behavior of water fleas Daphnia magna. The water fleas were fasted for 0, 0. 25, 1, 4, or 8 d, and then were allowed to graze on a mixture of al-gae Chlamydomonas sajao ( Cs) and Chlorella pyrenoidosa ( Cp) with a proportion of 5í104 cells/mL ( Cs):35í104 cells/mL (Cp), 20í104 cells/mL(Cs):20í104 cells/mL(Cp)and 35í104 cells/mL(Cs):5í104 cells/mL ( Cp) for three hours. Then the ingestion rate, filtration rate and food selectivity coefficient of water fleas on the two algae were analyzed and evaluated. The results showed that significantly high ingestion rate and filtration rate on Chlorella pyrenoidosa and significantly low ingestion rate and filtration rate on Chlamydomonas sajao were found in the water fleas fasted for long period ( 4 , and 8 d ) . In satiation or short fasting period ( 0 . 25 , and 1 d ) ( P<0. 05), however, the water fleas was found to prefer to Cs, and prefer Cp in long fasting period (4, and 8 d)(P<0. 05). Moreover, the foraging behaviors were not influenced by the relative food abundance of each green alga and the mechanisms of feeding selectivity were discussed based on the optimal foraging theory. The findings indicate that starvation affects the selectivity of wate fleas for algal food.%研究了不同饥饿时间下大型溞Daphnia magna (体长约3 mm)对沙角衣藻Chlamydomonas sajao和蛋白核小球藻Chlorella pyrenoidos的摄食选择性。沙角衣藻与蛋白核小球藻相比,具有较高的适口性,但营养价值相对较低。按照沙角衣藻和蛋白核小球藻的比例分别为5×104.35×104、20×104.20×104、35×104.5×104 cells/mL混合投喂饥饿0、0·25、1、4、8 d的大型溞,3 h后测定大型溞的摄食率、滤水率和食物选择系数。结果表明:与饱食组和短时间饥饿(0·25、1 d)组相比,长时间饥饿(4、8 d)导致大型溞对蛋白核小球藻的摄食率和滤水率显著增加(P<0·05),而对沙角

  11. DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, Florian [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Bourdineaud, Jean-Paul [UMR 5805 EPOC – OASU, Station marine d’Arcachon, Université Bordeaux 1, Arcachon 33120 (France); Plaire, Delphine; Adam-Guillermin, Christelle [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Alonzo, Frédéric, E-mail: frederic.alonzo@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France)

    2015-06-15

    Highlights: • We exposed three successive generations of Daphnia magna to chronic gamma radiation. • We examined DNA alterations and effects on survival, growth and reproduction. • DNA alterations were accumulated over a generation and transmitted to the progeny. • Effects on survival and reproduction, and delay in growth increased over generations. - Abstract: This study examined chronic effects of external Cs-137 gamma radiation on Daphnia magna exposed over three successive generations (F0, F1 and F2) to environmentally relevant dose rates (ranging from 0.007 to 35.4 mGy h{sup −1}). Investigated endpoints included survival, growth, reproduction and DNA alterations quantified using random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Results demonstrated that radiation effects on survival, growth and reproduction increased in severity from generation F0 to generation F2. Mortality after 21 days at 35.4 mGy h{sup −1} increased from 20% in F0 to 30% in F2. Growth was affected by a slight reduction in maximum length at 35.4 mGy h{sup −1} in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h{sup −1} in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h{sup −1} in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h{sup −1} in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days) and from F0 to F2 (0.070 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days), demonstrating their rapid accumulation in F0 daphnids and their transmission to offspring generations. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in F1, with no effect on survival, a slight reduction of 12% in 21 day-fecundity at 35.4 mGy h{sup −1} and DNA alterations significant at highest

  12. Comparative acute toxicity of leachates from plastic products made of polypropylene, polyethylene, PVC, acrylonitrile-butadiene-styrene, and epoxy to Daphnia magna.

    Science.gov (United States)

    Lithner, Delilah; Nordensvan, Ildikó; Dave, Göran

    2012-06-01

    The large global production of plastics and their presence everywhere in the society and the environment create a need for assessing chemical hazards and risks associated with plastic products. The aims of this study were to determine and compare the toxicity of leachates from plastic products made of five plastics types and to identify the class of compounds that is causing the toxicity. Selected plastic types were those with the largest global annual production, that is, polypropylene, polyethylene, and polyvinyl chloride (PVC), or those composed of hazardous monomers (e.g., PVC, acrylonitrile-butadiene-styrene [ABS], and epoxy). Altogether 26 plastic products were leached in deionized water (3 days at 50°C), and the water phases were tested for acute toxicity to Daphnia magna. Initial Toxicity Identification Evaluations (C18 filtration and EDTA addition) were performed on six leachates. For eleven leachates (42%) 48-h EC50s (i.e the concentration that causes effect in 50 percent of the test organisms) were below the highest test concentration, 250 g plastic/L. All leachates from plasticized PVC (5/5) and epoxy (5/5) products were toxic (48-h EC50s ranging from 2 to 235 g plastic/L). None of the leachates from polypropylene (5/5), ABS (5/5), and rigid PVC (1/1) products showed toxicity, but one of the five tested HDPE leachates was toxic (48-h EC50 17-24 g plastic/L). Toxicity Identification Evaluations indicated that mainly hydrophobic organics were causing the toxicity and that metals were the main cause for one leachate (metal release was also confirmed by chemical analysis). Toxic chemicals leached even during the short-term leaching in water, mainly from plasticized PVC and epoxy products.

  13. Assessing the environmental hazard of individual and combined pharmaceuticals: acute and chronic toxicity of fluoxetine and propranolol in the crustacean Daphnia magna.

    Science.gov (United States)

    Varano, Valentina; Fabbri, Elena; Pasteris, Andrea

    2017-08-01

    Pharmaceuticals are widespread emerging contaminants and, like all pollutants, are present in combination with others in the ecosystems. The aim of the present work was to evaluate the toxic response of the crustacean Daphnia magna exposed to individual and combined pharmaceuticals. Fluoxetine, a selective serotonin re-uptake inhibitor widely prescribed as antidepressant, and propranolol, a non-selective β-adrenergic receptor-blocking agent used to treat hypertension, were tested. Several experimental trials of an acute immobilization test and a chronic reproduction test were performed. Single chemicals were first tested separately. Toxicity of binary mixtures was then assessed using a fixed ratio experimental design. Five concentrations and 5 percentages of each substance in the mixture (0, 25, 50, 75, and 100%) were tested. The MIXTOX model was applied to analyze the experimental results. This tool is a stepwise statistical procedure that evaluates if and how observed data deviate from a reference model, either concentration addition (CA) or independent action (IA), and provides significance testing for synergism, antagonism, or more complex interactions. Acute EC50 values ranged from 6.4 to 7.8 mg/L for propranolol and from 6.4 to 9.1 mg/L for fluoxetine. Chronic EC50 values ranged from 0.59 to 1.00 mg/L for propranolol and from 0.23 to 0.24 mg/L for fluoxetine. Results showed a significant antagonism between chemicals in both the acute and the chronic mixture tests when CA was adopted as the reference model, while absence of interactive effects when IA was used.

  14. Effects of charge and surface ligand properties of nanoparticles on oxidative stress and gene expression within the gut of Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, Gustavo A.; Lohse, Samuel E.; Torelli, Marco; Murphy, Catherine; Hamers, Robert J.; Orr, Galya; Klaper, Rebecca D.

    2015-05-01

    Concern has been raised regarding the current and future release of engineered nanomaterials into aquatic environments from industry and other sources. However, not all nanomaterials may cause an environ-mental impact and identifying which nanomaterials may be of greatest concern has been difficult. It is thought that the surface groups of a functionalized nanoparticles (NPs) may play a significant role in determining their interactions with aquatic organisms, but the way in which surface properties of NPs impact their toxicity in whole organisms has been minimally explored. A major point of interaction of NPs with aquatic organisms is in the gastrointestinal tract as they ingest particulates from the water column or from the sediment. The main goal of this study was to use model gold NP (AuNPs) to evaluate the potential effects of the different surfaces groups on NPs on the gut of an aquatic model organism, Daphnia magna. In this study, we exposed daphnids to a range of AuNPs concentrations and assessed the impact of AuNP exposure in the daphnid gut by measuring reactive oxygen species (ROS) production and expression of genes associated with oxidative stress and general cellular stress: glutathione S-transferase(gst), catalase (cat), heat shock protein 70 (hsp70), and metallothionein1 (mt1). We found ROS formation and gene expression were impacted by both charge and the specific surface ligand used. We detected some degree of ROS production in all NP exposures, but positively charged AuNPs induced a greater ROS response. Similarly, we observed that, compared to controls, both positively charged AuNPs and only one negatively AuNP impacted expression of genes associated with cellular stress. Finally, ligand-AuNP exposures showed a different toxicity and gene expression profile than the ligand alone, indicating a NP specific effect.

  15. Uncovering Ultrastructural Defences in Daphnia magna – An Interdisciplinary Approach to Assess the Predator-Induced Fortification of the Carapace

    Science.gov (United States)

    Rabus, Max; Söllradl, Thomas; Clausen-Schaumann, Hauke; Laforsch, Christian

    2013-01-01

    The development of structural defences, such as the fortification of shells or exoskeletons, is a widespread strategy to reduce predator attack efficiency. In unpredictable environments these defences may be more pronounced in the presence of a predator. The cladoceran Daphniamagna (Crustacea: Branchiopoda: Cladocera) has been shown to develop a bulky morphotype as an effective inducible morphological defence against the predatory tadpole shrimp Triopscancriformis (Crustacea: Branchiopoda: Notostraca). Mediated by kairomones, the daphnids express an increased body length, width and an elongated tail spine. Here we examined whether these large scale morphological defences are accompanied by additional ultrastructural defences, i.e. a fortification of the exoskeleton. We employed atomic force microscopy (AFM) based nanoindentation experiments to assess the cuticle hardness along with tapping mode AFM imaging to visualise the surface morphology for predator exposed and non-predator exposed daphnids. We used semi-thin sections of the carapace to measure the cuticle thickness, and finally, we used fluorescence microscopy to analyse the diameter of the pillars connecting the two carapace layers. We found that D. magna indeed expresses ultrastructural defences against Triops predation. The cuticle in predator exposed individuals is approximately five times harder and two times thicker than in control daphnids. Moreover, the pillar diameter is significantly increased in predator exposed daphnids. These predator-cue induced changes in the carapace architecture should provide effective protection against being crushed by the predator’s mouthparts and may add to the protective effect of bulkiness. This study highlights the potential of interdisciplinary studies to uncover new and relevant aspects even in extensively studied fields of research. PMID:23776711

  16. Effects of three pesticides on superoxide dismutase and glutathione-S-transferase activities and reproduction of Daphnia magna

    Directory of Open Access Journals (Sweden)

    Song Yuzhi

    2017-03-01

    Full Text Available Applying pesticides to crops is one of the causes of water pollution by surface runoff, and chlorpyrifos, trifluralin and chlorothalonil are used respectively as insecticide, herbicide and fungicide for crop plants widely. To explore effects of three pesticides on aquatic organisms, superoxide dismutase (SOD and glutathione S-transferase (GST activities were determined after 24 h and 48 h exposure of D. magna with ages of 6–24 h to several low concentrations of chlorpyrifos (0.36, 0.72, 1.43, 2.86, 5.72 μg∙L−1, trifluralin (0.17, 0.33, 0.66, 1.33, 2.65 mg∙L−1 and chlorothalonil (0.09, 0.18, 0.36, 0.72, 1.43 mg∙L−1 respectively. Main reproductive parameters including first pregnancy time, first brood time, the number of first brood and total fecundity after 21 d exposures at the same concentrations of pesticides as described above were also measured. The results showed that the activities of GST increased in lower concentrations and decreased in higher concentrations after 24 h exposure to three pesticides, respectively. The activities of SOD showed the same changes after 48 h exposure. With the time prolonged, the activities of GST decreased while the activities of SOD increased. After 21 d exposure, the first pregnancy time and first brood time were delayed, while the number of the first brood and total fecundity per female decreased with increasing concentrations. These results corroborated that GST activity was more sensitive to those pesticides than SOD activity, and there was a significant relationship between total fecundity and pesticides-dose(r>0.94, n=6, GST activity after 48 h exposure and total fecundity after 21 d exposure (r>0.92, n=6.

  17. 三种典型渔药对大型溞(Daphnia magna)的急性毒性及其关键环境影响因子分析%Acute toxicity of three typical fish drugs to Daphnia magna and analysis of the key environmental factors

    Institute of Scientific and Technical Information of China (English)

    聂湘平; 王翔; 史方

    2006-01-01

    测试了三种典型渔药三氯异氰尿酸(Trichloroisocyanuric acid , TCCA)、叔丁基对羟基茴香醚(Butylated hydroxyanisole , BHA)、盐酸环丙沙星(Ciprofloxacin hydrochloride , CPFX)对大型溞(Daphnia magna)的急性毒性.结果表明,对于大型溞的毒性由大到小的顺序为:三氯异氰尿酸,叔丁基对羟基茴香醚,盐酸环丙沙星, 48 h LC50分别为0.19 mg·L-1, 3.15 mg·L-1和135.15 mg·L-1.通过三因素三水平正交试验分析了主要环境因子pH值、硬度、腐殖酸对三种渔药对大型溞毒性的影响, 发现pH显著影响TCCA的毒性, 硬度显著影响CPFX的毒性, 而BHA毒性受环境因素影响不显著.

  18. Evaluation of the Gravataí River sediment quality (Rio Grande do Sul- Brazil using Daphnia magna (Straus, 1820 as the test-organism for toxicity assays Avaliação da qualidade dos sedimentos do rio Gravataí (Rio Grande do Sul - Brasil a partir de testes de toxicidade utilizando Daphnia magna (Straus, 1820 como organismo-teste

    Directory of Open Access Journals (Sweden)

    Fabiane Lucheta

    2010-12-01

    Full Text Available AIM: Persistent pollutants released to riverbeds return to the trophic system, damaging living organisms thereof. Ecotoxicological assays express the effect of environmental interactions with organisms found there. Assays were performed with microcrustacean Daphnia magna (Straus, 1820 in sediment samples, from the headwaters to the mouth, in order to evaluate the Gravataí River quality; METHODS: Bottom sediment was used to evaluate the responses of cladocerans to environmental changes in 15 samples collected between Jan./06 and May/09. The microcrustaceans were submitted to stress for 21 days from birth (2-26 hours old. Duncan Test, percentage survival, reproduction and Spearman Correlation were used to evaluate the quality of the sites; RESULTS: Duncan Test showed a significant difference (p OBJETIVO: Poluentes persistentes lançados no leito dos rios retornam ao sistema trófico danificando os organismos que o integram. Os ensaios ecotoxicológicos expressam o efeito das interações ambientais com os organismos ali presentes. Visando avaliar a qualidade do rio Gravataí foram realizados ensaios com o microcrustáceo Daphnia magna (Straus, 1820, em amostras do sedimento, da nascente até a foz; MÉTODOS: Sedimento de fundo foi utilizado na avaliação das respostas dos cladóceros às alterações ambientais de 15 amostras coletadas entre Jan./06 e Maio/09. Os microcrustáceos foram colocados em situação de estresse durante 21 dias desde o início de suas vidas (2-26 horas. O Teste de Duncan, percentual de sobrevivência, reprodução e Correlação de Spearman foram utilizados para avaliar a qualidade dos locais; RESULTADOS: O Teste de Duncan mostrou diferença significativa (p < 0,05 na reprodução em 14 das 15 amostragens, sendo a ação crônica mais constante (88% que a aguda (23%. Somente em algumas ocasiões foram observadas alterações na sobrevivência e na reprodução relacionadas à estação climática ou regime de chuvas. Os

  19. Toxicity of noradrenaline, a novel anti-biofouling component, to two non-target zooplankton species, Daphnia magna and Ceriodaphnia dubia.

    Science.gov (United States)

    Overturf, C L; Wormington, A M; Blythe, K N; Gohad, N V; Mount, A S; Roberts, A P

    2015-05-01

    Noradrenaline (NA) is the active component of novel antifouling agents and acts by preventing attachment of fouling organisms. The goal of this study was to examine the toxicity of NA to the non-target zooplankton D. magna and C. dubia. Neonates were exposed to one of five concentrations of NA and effects on survival, reproduction and molting were determined. Calculated LC50 values were determined to be 46 and 38 μM in C. dubia and D. magna, respectively. A 10-day C. dubia study found that reproduction metrics were significantly impacted at non-lethal concentrations. In D. magna, concentrations greater than 40 μM significantly impacted molting. A toxicity test was conducted with D. magna using oxidized NA, which yielded similar results. These data indicate that both NA and oxidized NA are toxic to non-target zooplankton. Results obtained from this study can be used to guide future ecological risk assessments of catecholamine-based antifouling agents.

  20. Larvicidal activity of ajowan ( Trachyspermum ammi ) and Peru balsam ( Myroxylon pereira ) oils and blends of their constituents against mosquito, Aedes aegypti , acute toxicity on water flea, Daphnia magna , and aqueous residue.

    Science.gov (United States)

    Seo, Seon-Mi; Park, Hye-Mi; Park, Il-Kwon

    2012-06-13

    This study evaluated the larvicidal activity of 20 plant essential oils and components from ajowan ( Trachyspermum ammi ) and Peru balsam ( Myroxylon pereira ) oils against the mosquito, Aedes aegypti . Of the 20 plant essential oils, ajowan and Peru balsam oils at 0.1 mg/mL exhibited 100 and 97.5% larval mortality, respectively. At this same concentration, the individual constituents, (+)-camphene, benzoic acid, thymol, carvacrol, benzyl benzonate, and benzyl trans-cinnamate, caused 100% mortality. The toxicity of blends of constituents identified in two active oils indicated that thymol and benzyl benzoate were major contributors to the larvicidal activity of the artificial blend. This study also tested the acute toxicity of these two active oils and their major constituents against the water flea, Daphnia magna . Peru balsam oil and benzyl trans-cinnamate were the most toxic to D. magna. Two days after the treatment, residues of ajowan and Peru balsalm oils in water were 36.2 and 85.1%, respectively. Less than 50% of benzyl trans-cinnamate and thymol were detected in the water at 2 days after treatment. The results show that the essential oils of ajowan and Peru balsam and some of their constituents have potential as botanical insecticides against Ae. aegypti mosquito larvae.

  1. Application of a stable isotope technique to determine the simultaneous uptake of cadmium, copper, nickel, lead, and zinc by the water flea Daphnia magna from water and the green algae Pseudokirchneriella subcapitata.

    Science.gov (United States)

    Komjarova, Irina; Blust, Ronny

    2009-08-01

    Accumulation and toxicological effects of water and dietary metals in aquatic organisms can potentially be very different. Therefore, it is important to know the relative contribution of these different sources to metal exposure, availability, and accumulation. In the present study, a stable isotope technique was applied to investigate the uptake of Cd, Cu, Ni, Pb, and Zn by the green alga Pseudokirchneriella subcapitata and the water flea Daphnia magna during simultaneous exposure to the five metals at environmentally realistic concentrations from separate water and dietary routes. Green algae take up Cu faster compared to Cd, Ni, Pb, and Zn, and the distribution of metals between the external and internal compartments is dependent on metal and population growth stage. The metal accumulation reached a steady state within 24 to 48 h for all metals. Metal uptake rate constants from water were highest for Cu and lowest for Ni. Metal assimilation efficiencies from the food source varied with metal, ranging from approximately 80% in the case of Cd to near 0% in the case of Ni. Because the data for the different metals were obtained on the same multimetal-exposed organisms, the results are directly comparable among the metals. For all five metals studied, water appeared to be the most important route of uptake by D. magna.

  2. Quantifying sublethal effects of glyphosate and Roundup® to Daphnia magna using a fluorescence based enzyme activity assay and video tracking

    DEFF Research Database (Denmark)

    Roslev, Peter; R. Hansen, Lone; Ørsted, Michael

    on endpoints such as immobility and mortality. In this study, we investigated sublethal effects of glyphosate and Roundup® to D. magna using video tracking for quantifying behavioral changes, and a novel fluorescence based assay for measuring in vivo hydrolytic enzyme activity (FLEA assay). Roundup® exposure...... resulted in behavioral effects quantified as decreases in average swimming velocity and distance moved whereas the inactive time in defined arenas increased. Exposure of D. magna to binary mixtures of glyphosate and copper (Cu) attenuated acute metal toxicity. The results suggest that a combination...... of assays targeting in vivo enzyme activity and behavioral changes may be applied as a quantitative and sensitive tool for detecting sublethal effects of glyphosate and Roundup® to D. magna. The inhibitory effect of Roundup® on alkaline phosphatase in non-target organisms warrants further investigations...

  3. Bioassay using Daphnia magna Straus, 1820 to evaluate the sediment of Caí River (Rio Grande do Sul, Brazil Bioensaios utilizando Daphnia magna Straus, 1820 na avaliação do sedimento do rio Caí (Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Nara Regina Terra

    2010-12-01

    Full Text Available AIM: The Caí River is one of the five that form the Guaiba Lake Hydrographic Basin. It is used for public water supply in the capital of Rio Grande do Sul; METHODS: Sediment samples for toxicity test (21 days with Daphnia magna were taken from four sites between the middle and upper reaches in this river from Mar./05 to June/09. Their quality is described based on the survival and reproduction responses of 440 test-organisms from the beginning of their lives (2-26 hours. Percentage survival, mean and total reproduction were calculated for this evaluation. Spearman correlation and Duncan Test were used to compare reproduction between sites and variation of this parameter statistically over time. Bacteriological, physical and chemical parameters in water samples collected during the period of the study were considered; RESULTS: Acute toxicity was observed in 18% of the samples and chronic toxicity in 95%, indicating the presence of small doses of environmental aggressors. Mortality and reproduction did not always follow the same trend, and it became clear that the reproductive activity was more sensitive when compared using contaminated samples. Duncan Test showed up to four clusters at sites Ca070, Ca092 and Ca245, indicating reproduction variation. A pattern of monthly rainfall distribution was not observed, nor was there a correlation between survival, reproduction and rainfall; CONCLUSIONS: Presence of low concentrations of xenobiotics was confirmed by physical, chemical, bacteriological and metal responses in water samples, besides a small effect on survival and constant change in reproductive activity in the organisms exposed to sediment samples. Long duration assays are more appropriate to evaluate environmental samples, since usually changes in ecosystem quality are tenuous and not detected by short tests. Caí River quality has improved, but further studies are needed to confirm this trend, and to follow the history of the area with a

  4. Effects of Microcystin-free and Microcystin-containing strains of the Cyanobacterium Microcystis aeruginosa on growth of the grazer Daphnia magna

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.

    2003-01-01

    Harmful effects of the common bloom-forming cyanobacterium Microcystis aeruginosa on the grazer Daphnia have been explained from morphological features, nutritional insufficiency, and the production of toxins called microcystins. The effects of four M. aeruginosa strains, including one free of

  5. Effects of microcystin-free and Microcystin containing strains of the cyanobacterium Microcystis aeruginosa on growth of the grazer Daphnia magna

    NARCIS (Netherlands)

    Lürling, M.

    2003-01-01

    Harmful effects of the common bloom-forming cyanobacterium Microcystis aeruginosa on the grazer Daphnia have been explained from morphological features, nutritional insufficiency, and the production of toxins called microcystins. The effects of four M. aeruginosa strains, including one free of

  6. Joint Toxicity of Glyphosate and As(Ⅲ) to Daphnia magna in Aquatic Environment%水环境中草甘膦和三价砷对大型溞的联合毒性评价

    Institute of Scientific and Technical Information of China (English)

    许杨贵; 李晶; 秦俊豪; 李琦; 黎华寿

    2015-01-01

    以大型潘(Daphnia magna)为试验生物,进行草甘膦和As(Ⅲ)对大型溞24、48 h的单一毒性和联合毒性评价.结果表明,草甘膦和As(Ⅲ)对大型溞24、48 h半致死浓度(LC50)分别为54.12、51.12 mg·L-1和7.47、6.07 mg·L-1.基于单一草甘膦和As(Ⅲ)以及两者的等毒性混合的浓度-效应曲线,用Logistic regression模型和反应曲面模型对其单一和联合毒性的浓度-致死效应进行预测和曲面图的绘制,并用洛伊参数反应曲面模型(CARS)和反应添加剂反应面模型(RARS)预测Mix-LC50的联合毒性:在等毒性比浓度条件下,草甘膦和As(Ⅲ)的联合毒性表现为拮抗作用.

  7. Plant Mediated Green Synthesis of CuO Nanoparticles: Comparison of Toxicity of Engineered and Plant Mediated CuO Nanoparticles towards Daphnia magna

    Directory of Open Access Journals (Sweden)

    Sadia Saif

    2016-11-01

    Full Text Available Research on green production methods for metal oxide nanoparticles (NPs is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM, energy dispersive X-ray (EDX, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS and dynamic light scattering (DLS. Plant-mediated CuO nanoparticles were found to be oval shaped and well dispersed in suspension. XPS confirmed the elemental composition of P. acerifolium-mediated copper nanoparticles as comprised purely of copper and oxygen. DLS measurements and ion release profile showed that P. acerifolium-mediated copper nanoparticles were more stable than the engineered CuO NPs. Copper oxide nanoparticles are used in many applications; therefore, their potential toxicity cannot be ignored. A comparative study was performed to investigate the bio-toxic impacts of plant-synthesized and engineered CuO nanoparticles on water flea Daphnia. Experiments were conducted to investigate the 48-h acute toxicity of engineered CuO NPs and plant-synthesized nanoparticles. Lower EC50 value 0.102 ± 0.019 mg/L was observed for engineered CuO NPs, while 0.69 ± 0.226 mg/L was observed for plant-synthesized CuO NPs. Additionally, ion release from CuO nanoparticles and 48-h accumulation of these nano CuOs in daphnids were also calculated. Our findings thus suggest that the contribution of released ions from nanoparticles and particles/ions accumulation in Daphnia needs to be interpreted with care.

  8. Plant Mediated Green Synthesis of CuO Nanoparticles: Comparison of Toxicity of Engineered and Plant Mediated CuO Nanoparticles towards Daphnia magna.

    Science.gov (United States)

    Saif, Sadia; Tahir, Arifa; Asim, Tayyaba; Chen, Yongsheng

    2016-11-09

    Research on green production methods for metal oxide nanoparticles (NPs) is growing, with the objective to overcome the potential hazards of these chemicals for a safer environment. In this study, facile, ecofriendly synthesis of copper oxide (CuO) nanoparticles was successfully achieved using aqueous extract of Pterospermum acerifolium leaves. P. acerifolium-fabricated CuO nanoparticles were further characterized by UV-Visible spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). Plant-mediated CuO nanoparticles were found to be oval shaped and well dispersed in suspension. XPS confirmed the elemental composition of P. acerifolium-mediated copper nanoparticles as comprised purely of copper and oxygen. DLS measurements and ion release profile showed that P. acerifolium-mediated copper nanoparticles were more stable than the engineered CuO NPs. Copper oxide nanoparticles are used in many applications; therefore, their potential toxicity cannot be ignored. A comparative study was performed to investigate the bio-toxic impacts of plant-synthesized and engineered CuO nanoparticles on water flea Daphnia. Experiments were conducted to investigate the 48-h acute toxicity of engineered CuO NPs and plant-synthesized nanoparticles. Lower EC50 value 0.102 ± 0.019 mg/L was observed for engineered CuO NPs, while 0.69 ± 0.226 mg/L was observed for plant-synthesized CuO NPs. Additionally, ion release from CuO nanoparticles and 48-h accumulation of these nano CuOs in daphnids were also calculated. Our findings thus suggest that the contribution of released ions from nanoparticles and particles/ions accumulation in Daphnia needs to be interpreted with care.

  9. Avaliação ecotoxicológica utilizando bioensaios com daphnia magna em água de lavoura de arroz no município de Mostardas, RS, Brasil

    Directory of Open Access Journals (Sweden)

    Thelma Duarte Brandolt

    2010-01-01

    Full Text Available Este estudo objetivou avaliar a toxicidade aguda da água proveniente dos canais de uma lavoura orizícola irrigada pela Lagoados Patos, na localidade de Mostardas/RS, através da utilização de bioensaios com o organismo teste Daphnia magna. Foramescolhidos 3 locais de amostragem: um próximo ao ponto de captação da água (P1; um na saída de uma área de plantio (P2, e outrono dreno de retorno da água para a Lagoa dos Patos (P3. As coletas foram realizadas em três momentos do ciclo produtivo: antes,durante e após a irrigação, correspondendo aos meses de Novembro de 2007, Janeiro e Março de 2008. Os testes foram realizados noLaboratório de Ecotoxicologia da UNISC, seguindo a norma técnica ABNT 12713. Após 48 horas de exposição aos efluentes,observou-se o número de indivíduos imóveis por concentração e calculou-se a porcentagem de imobilidade. O resultado do teste foiexpresso pela Concentração Efetiva Inicial Mediana - CE(I50 48h, que corresponde à concentração da amostra que causou efeitoagudo a 50% dos organismos. Os resultados indicaram, nos diferentes locais de coleta e estágios de manejo da lavoura, uma baixatoxicidade para este bioindicador, ou mesmo ausência de toxicidade, uma vez que apresentaram uma CE(I 50 48h superior a 75% naescala de toxicidade relativa, de acordo com o sistema de monitoramento estabelecido durante o ciclo de produção. Neste sentido,visando à corroboração dos mesmos, sugere-se o aumento da periodicidade do desenho experimental, bem como a realização dascoletas em período mais próximo da aplicação dos agroquímicos.Abstract This study aimed to evaluate the acute toxicity ofthe water from the channels of rice fields irrigated by the Lagoados Patos, in the town of Mostardas,/RS, through the use of bioassays with the test organism Daphnia magna. Threesampling locations we selected: one near the point of watercatchments (P1, an output of an area planting (P2, and anotheron the drain

  10. Study on Application of Daphnia magna and Submerged Vegetation to Remediation of Landscape Water%食藻虫引导的沉水植被修复景观水体的应用研究

    Institute of Scientific and Technical Information of China (English)

    夏哲韬; 史惠祥; 李遥

    2011-01-01

    A field test of bioremediation of eutrophic water by Daphnia magna and submerged vegetation was conducted in Xixi wetland. Domesticated Daphnia magna was introduced into the water body of restoration area to ingest cyanobacteria and other phytoplanktons, and subsequently, submerged plants, such as Vallisneria, Hydrilla verticillata, Elodea canadensis and Potamogeton pectinatus were transplanted. From September 2010 to February 2011, water samples were monitored to investigate bioremediation efficiency and stability. The experiment data show that compared with the control area, Chl-a, TN, N03- -N, NH4+ -N, TP, PO43- -P and CODMn in the water body of restoration area are decreased by 45.6% , 68.8% , 97.6% , 71.5% , 65.7% , 68.5% and 67.4% respectively, DO is increased by 88.3% , and Secchi depth (SD) reaches over 2.0 m. Overall, the water quality meets the II to HI criteria specified in the national surface water quality standard. In March 2011, the inferior V water was introduced into the restoration area to test the effectiveness of the established experiment system. The results show that after one month, all the water-quality indices are significantly lower compared with the control area (P <0.01), TN, TP and CODMn are reduced by 78.2% , 50% and 43.7% , the DO is increased by 22.4% , and the SD reaches 1.5 m.%在西溪湿地进行了食藻虫引导沉水植被生态修复富营养化水体的现场试验.在修复区水体中引入经过驯化的食藻虫来滤食蓝藻等浮游藻类,然后移植苦草、轮叶黑藻、伊乐藻、龙须眼子菜等沉水植物.于2010年9月-2011年2月,对水体的水质指标进行了逐月监测,分析对西溪湿地水体的净化效果及其稳定性.结果表明:修复区水体的叶绿素a、TN、NO3- -N、NH4+ -N、TP、PO43- -P和CODMn浓度相比于对照区分别低45.6%、68.8%、97.6%、71.5%、65.7%、68.5%和67.4%,DO增加了88.3%,水体透明度达到2.0m以上,水质达到国家地

  11. Cu2+、Pb2+和Zn2+对大型溞的单一及联合毒性效应%INDIVIDUAL TOXICITY AND JOINT TOXICITY OF COPPER LEAD AND ZINC IONC TO DAPHNIA MAGNA

    Institute of Scientific and Technical Information of China (English)

    丁婵娟; 付荣恕

    2013-01-01

    Research on toxic effect of heavy metal combined pollution plays an importance role in ecological environment evaluation. The individual toxicity and the joint toxicity of Cu2+ 、Pb2 + and Zn2+ to Daphnia magna were investigated with a static test method. Results showed that the toxicity of Cu2+、Pb2+ and Zn2+ was degressive and the joint toxicity of Cu2 + - Zn2 + 、 Cu2 + - Pb2 + and Cu2 + - Pb2 + - Zn2 + was synergetic action, while Pb2 + -Zn + was antagonistic action. Joint toxicity was affected by combined gradation of poisons but it had no relation with ratio of chemical and exposure time.%重金属的复合污染毒性效应研究在生态环境评价中具有重要的实践意义.本研究以大型溞为试验材料,通过静水生物测试法,研究Cu2+、Pb2+和Zn2+三种金属离子对其的单一毒性及联合毒性效应.单一毒性实验结果表明,Cu2+、Pb2+和Zn2+对大型潘的毒性大小顺序为Cu2+> Pb2+> Zn2+.联合毒性实验结果表明,Cu2+-Zn2+、Cu2+-Pb2+和Cu2+-Pb2+-Zn2+三组的联合毒性均表现为协同作用,Pb2+-Zn2+的联合毒性表现为拮抗作用.联合毒性与毒物的组合有关,与毒物配比和暴露时间没有关系.

  12. Identification of compounds bound to suspended solids causing sub-lethal toxic effects in Daphnia magna. A field study on re-suspended particles during river floods in Ebro River.

    Science.gov (United States)

    Rivetti, Claudia; Gómez-Canela, Cristian; Lacorte, Silvia; Díez, Sergi; Lázaro, Wilkinson L; Barata, Carlos

    2015-04-01

    Identifying chemicals causing adverse effects in organisms present in water remains a challenge in environmental risk assessment. This study aimed to assess and identify toxic compounds bound to suspended solids re-suspended during a prolonged period of flushing flows in the lower part of Ebro River (NE, Spain). This area is contaminated with high amounts of organochlorine and mercury sediment wastes. Chemical characterization of suspended material was performed by solid phase extraction using a battery of non-polar and polar solvents and analyzed by GC-MS/MS and LC-MS/MS. Mercury content was also determined for all sites. Post-exposure feeding rates of Daphnia magna were used to assess toxic effects of whole and filtered water samples and of re-constituted laboratory water with re-suspended solid fractions. Organochlorine and mercury residues in the water samples increased from upstream to downstream locations. Conversely, toxic effects were greater at the upstream site than downstream of the superfund Flix reservoir. A further analysis of the suspended solid fraction identified a toxic component eluted within the 80:20 methanol:water fraction. Characterization of that toxic component fraction by LC-MS/MS identified the phytotoxin anatoxin-a, whose residue levels were correlated with observed feeding inhibition responses. Further feeding inhibition assays conducted in the lab using anatoxin-a produced from Planktothrix agardhii, a filamentous cyanobacteria, confirmed field results. This study provides evidence that in real field situation measured contaminant residues do not always agree with toxic effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. magna (Straus, 1820.

    Directory of Open Access Journals (Sweden)

    Hatice Parlak

    2015-12-01

    Full Text Available Nif Çayi Kirletilmiş Tatli Su ve Sedimentinin Daphnia magna (Strauss, 1820 Üzerine Akut Ve Kronik Toksisitesi. Nif Çayı Endüstriyel, evsel ve tarımsal deşarjlar ile doğrudan kirlenmektedir. Çayın suyunun evsel ve endüstriyel alanlarda sulama ve yıkama suyu olarak kullanılması rahatsızlık verici boyuttadır, bu nedenle doğal populasyonlar için potansiyel toksisitesinin bilinmesi büyük öneme sahiptir. Bu çalışmanın amacı Nif Çayı su ve sediment örneklerinin su piresi Daphnia magna kullanılarak toksisitesinin belirlenmesidir. Su ve sediment örneklerinin letal toksisitesi 48-saat akut test, subletal toksisite ise 7-gün kronik test ile gerçekleştirilmiştir. D.magna kullanılarak yapılan 48 saat Akut test sonuçlarına göre LC 50 değerleri su örnekleri için 6.8 ile 12.67 µl/L arasında sediment örnekleri içn 6.826 ile 38.038 µg/L arasında bulunmuştur. Subletal konsantrasyonlara maruz bırakılarak yapılan kronik testler sonucunda tüm istasyonlardan alınan su ve sediment örneklerin canlının üremesi üzerine negatif etkisi olduğu gözlenmiştir. Elde edilen veriler ışığında bu deneme sisteminin rutin kirlilik belirleme çalışmaları için uygunluğu tespit edilmiştir

  14. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    Science.gov (United States)

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  15. Making the Most of the "Daphnia" Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

    Science.gov (United States)

    Corotto, Frank; Ceballos, Darrel; Lee, Adam; Vinson, Lindsey

    2010-01-01

    Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

  16. Exposure of juvenile Danio rerio to aged TiO₂ nanomaterial from sunscreen.

    Science.gov (United States)

    Fouqueray, Manuela; Noury, Patrice; Dherret, Lysiane; Chaurand, Perrine; Abbaci, Khedidja; Labille, Jerome; Rose, Jerome; Garric, Jeanne

    2013-05-01

    The toxicity of dietary exposure to artificially aged TiO₂ nanomaterial (T-Lite) used in sunscreen cream was studied on Danio rerio. Embryolarval assays were conducted to assess the effects of TiO₂ residues of nanomaterial (RNM) on fish early life stages. Juvenile fishes were exposed by the trophic route in two experiments. During the first experiment, juvenile fishes were exposed to TiO₂ RNM for 14 days by adding RNM to commercial fish food. The second one consisted in producing a trophic food chain. Pseudokirchneriella subcapitata algae, previously contaminated with TiO₂ RNM in growth medium, was used to feed Daphnia magna neonates over a 48-h period. Daphnia were used next to feed juvenile fishes for 7 days. Accumulation of Ti, life traits (survival and growth) and biochemical parameters such as energy reserves, digestive (trypsin, esterase, cellulose and amylase) and antioxidant (superoxide dismutase and catalase) enzyme activity were measured at the end of exposures. As expected in the receiving aquatic system, TiO2 RNM at low concentrations caused a low impact on juvenile zebrafish. A slight impact on the early life stage of zebrafish with premature hatching was observed, and this effect appeared mainly indirect, due to possible embryo hypoxia. When juvenile fish are exposed to contaminated food, digestive enzyme activity indicated a negative effect of TiO₂ RNM. Digestive physiology was altered after 14 days of exposure and seemed to be an indirect target of TiO₂ RNM when provided by food.

  17. Context-dependent individual behavioral consistency in Daphnia

    DEFF Research Database (Denmark)

    Heuschele, Jan; Ekvall, Mikael T.; Bianco, Giuseppe

    2017-01-01

    , whereas studies focusing on smaller aquatic organisms are still rare. Here, we show individual differences in the swimming behavior of Daphnia magna, a clonal freshwater invertebrate, before, during, and after being exposed to a lethal threat, ultraviolet radiation (UVR). We show consistency in swimming...

  18. A comparative study between the two biotic ligand models (BLMs) on predicting the acute Zn toxicity to Daphnia magna%两种生物配体模型(BLM)预测Zn对大型蚤急性毒性的比较

    Institute of Scientific and Technical Information of China (English)

    陈中智; 朱琳; 姚琨; 李燕; 刘硕

    2008-01-01

    通过天津地区一系列景观水体和配制的模拟溶液,评价应用于大型蚤(Daphnia magna)毒性预测的两种急性Zn-生物配体(BLM)模型(模型A和模型B)的预测能力.采用Visual MINTEQ 2.5.2进行BLM的相关计算和金属形态分析.对一定水化学参数的测定表明,根据Zn对大型蚤的急性毒性数据建立的模型B能够在Zn的生态风险评价中考虑其生物有效性,预测结果准确;以鱼类为对象开发并下调LA50后应用于水蚤毒性预测的模型A的预测值普遍高于实测值.可见,通过调整LA50拓展模型适用性的方法过于简单,还有待进一步研究.

  19. Cloning and expression analysis of a transformer gene in Daphnia pulex during different reproduction stages.

    Science.gov (United States)

    Chen, Ping; Xu, Shan-Liang; Zhou, Wei; Guo, Xiao-Ge; Wang, Chun-Lin; Wang, Dan-Li; Zhao, Yun-Long

    2014-05-01

    The full-length cDNA of a transformer gene (Dptra) was cloned from the cladoceran Daphnia pulex using RACE. Dptra expression was assessed by qPCR and whole-mount in situ hybridization in different reproductive stages. The Dptra cDNA, 1652bp in length, has a 1158-bp open reading frame that encodes a 385 amino acid polypeptide containing one Sex determination protein N terminal (SDP_N) superfamily, eight putative phosphorylation sites, and an arginine-serine (RS)-rich domain at the N-terminus. Dptra showed 81%, 53%, 51% and 45% identity to orthologous genes in Daphnia magna, Apis mellifera, Apis cerana and Bombus terrestris, respectively. Phylogenetic analysis based on deduced amino acid sequences revealed that Dptra clustered in the hymenopteran clade and was most closely related to D. magna and A. mellifera. qPCR showed that Dptra expression increased significantly (P<0.05) in different reproductive stages in the following order: male, ephippial female, parthenogenetic female, resting egg and juvenile female. Dptra expression is significantly different between males and females and it is significantly greater in ephippial females and males than in parthenogenetic D. pulex (with summer eggs). Whole-mount in situ hybridization revealed that Dptra was expressed at different levels between males and females. In males, hybridization signals were found in the first antennae, second antennae and thoracic limb, whereas expression levels in the corresponding sites of parthenogenetic and ephippial females were relatively weak. This suggests that the Dptra gene plays significant roles in switching modes of reproduction and in sexual differentiation. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Using Daphnia bio-sensor for random number generation

    Directory of Open Access Journals (Sweden)

    Đorđević Đorđe

    2013-01-01

    Full Text Available One of the most used bioassays for toxicity screening of chemicals and for toxicity monitoring of effluents and contaminated waters is the acute toxicity test performed with Daphnia Magna. Standard methods have been developed and gradually improved by national and international organizations dealing with toxicity testing procedure, in view of its application within a regulatory framework. As for all toxicity tests, the organisms used for the acute Daphnia magna assay have to be obtained from live stocks which are cultured in the laboratory on live food (micro-algae. The technical and biological problems inherent in year-round culturing and the culturing/maintenance costs of live stocks restricts its application to a limited number of highly specialized laboratories. This bottleneck in toxicity testing triggered investigations forward the concept of "microbiotests" or "small-scale" toxicity tests. This paper deals with the measurement of changes in the behavior of Daphniae using device BIOTOXINOMER, awarded by Ministry for Science and Technological Development of Republic Serbia with Diploma for best Innovation idea in year 2010 in category Medicine, Health, and Ecology. Actually, the main topic is digitalization of bio-monitoring results and random number generating on the base of Daphniae movement (distance. The on-line monitoring is available on site www.dundjer.co.rs/Daphniae and open-source software support is available on the same site. [Projekat Ministarstva nauke Republike Srbije, br. III44006 i br. TR37003

  1. 基于高锰酸钾及氯化锰对大型蚤毒性效应的水质应急监测技术%THE EMERGENCY MONITORING OF POTASSIUM PERMANGANATE AND MANGANESE CHLORIDE BASED ON THE TOXIC EFFECTS OF DAPHNIA MAGNA

    Institute of Scientific and Technical Information of China (English)

    付秀娥; 刘洋; 曾阳; 任宗明

    2012-01-01

    利用LC50 - 24 h作为1个毒性单位(Toxic Unit,TU),探讨了利用高锰酸钾及氯化锰对24-48 h龄大型蚤急性毒性效应,实现水体污染事故的应急监测.结果表明,高锰酸钾对大型蚤的LC50 - 24 h为0.187 mg/L,属于高毒类,氯化锰对大型蚤的LC50 - 24 h为579 mg/L,属于低毒类.在1,2,5,10,20,50TU暴露下,高锰酸钾导致大型蚤半数死亡时间分别为24h、5.9h、2.9h、1.4h、0.9h和0.6h,氯化锰导致大型蚤半数死亡时间分别为24h、8.6h、4.7h、1.7h、0.8h和0.4h,表明半数死亡时间与浓度呈现明显幂指数关系,可以实现水体污染事故应急监测的定性和半定量分析.因此,本项技术可以对水体污染状况和程度实现原位快速检测.%In this study, LC50 - 24 h was regarded as one TU to discuss the technology of emergency monitoring of potassium permanganate and manganese chloride pollution used Daphnia magna with life stage of 24 -48 h. The results showed that the LC50 -24 h of potassium permanganate and manganese chloride was 0. 187 mg/L and 579 mg/L respectively. In the exposure of 1, 2, 5 , 10, 20, and 50 TU potassium permanganate, the Time of Half Lethal (THL) was 24 h, 5. 9 h, 2. 9 h, 1.4 h, 0. 9 h and 0. 6 h respectively, and in the exposure of 1, 2, 5 , 10, 20, and 50 TU manganese chloride, THL was 24 h, 8. 6 h, 4.7 h, 1. 7 h, 0. 8 h and 0.4 h respectively. It suggested that it was evident negative relationship between the exposure concentration and the half death time. THL could reflect the pollution level, and with the help of THL, qualitative and quantitative analysis could be made on the emergency accidents. Meanwhile, the behavioral responses of Daphnia magna could be used in the analysis of emergency accidents.

  2. Effect of body size on toxicity of zinc in neonates of four differently sized Daphnia species

    NARCIS (Netherlands)

    Vesela, S.; Vijverberg, J.

    2007-01-01

    The sensitivity of neonates of four Daphnia species to zinc was tested in relation to their mean body size. These mean sizes of these four Daphnia spp were: D. magna, 0.813 ± 0.055 mm, D.␣pulicaria, 0.745 ± 0.063 mm, D. pulex, 0.645 ± 0.044 mm and D. galeata, 0.611 ± 0.058 mm. A positive relationshi

  3. The good, the bad and the plenty: interactive effects of food quality and quantity on the growth of different Daphnia species.

    Science.gov (United States)

    Bukovinszky, Tibor; Verschoor, Antonie M; Helmsing, Nico R; Bezemer, T Martijn; Bakker, Elisabeth S; Vos, Matthijs; de Senerpont Domis, Lisette N

    2012-01-01

    Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.e. Daphnia galeata x hyalina, D. pulicaria and D. magna, on their algal food (Scenedesmus obliquus), varying in carbon to phosphorus (C∶P) ratios and quantities (concentrations). In the first experiment, we found a strong positive effect of the phosphorus content of food on growth of Daphnia, both in their early and late juvenile development. Variation in the relationship between the P-content of animals and their growth rate reflected interspecific differences in nutrient requirements. Although growth rates typically decreased as development neared maturation, this did not affect these species-specific couplings between growth rate and Daphnia P-content. In the second experiment, we examined the effects of food quality on Daphnia growth at different levels of food quantity. With the same decrease in P-content of food, species with higher estimated P-content at zero growth showed a larger increase in threshold food concentrations (i.e. food concentration sufficient to meet metabolic requirements but not growth). These results suggest that physiological processes such as maintenance and growth may in combination explain effects of food quality and quantity on consumers. Our study shows that differences in response to variation in food quality and quantity exist between species. As a consequence, species-specific effects of food quality on consumer growth will also determine how species deal with varying food levels, which has implications for resource-consumer interactions.

  4. Experimental evolution reveals high insecticide tolerance in Daphnia inhabiting farmland ponds

    NARCIS (Netherlands)

    Jansen, M.; Coors, A.; Vanoverbeke, J.; Schepens, M.; de Voogt, P.; De Schampelaere, K.A.C.; De Meester, L.

    2015-01-01

    Exposure of nontarget populations to agricultural chemicals is an important aspect of global change. We quantified the capacity of natural Daphnia magna populations to locally adapt to insecticide exposure through a selection experiment involving carbaryl exposure and a control. Carbaryl tolerance

  5. Multigenerational genomic responses to dietary phosphorus and temperature in Daphnia.

    Science.gov (United States)

    Jalal, Marwa; Shala, Nita K; Wojewodzic, Marcin W; Andersen, Tom; Hessen, Dag O

    2014-08-01

    Temperature and nutrient availability are both hypothesized to affect organisms at the cellular and genomic levels. In this multigenerational study, Daphnia magna (D. magna) and Daphnia pulex (D. pulex) were maintained at high (20 °C) and low (10 °C) temperatures and nourished with phosphorus (P)-sufficient (50 μmol/L) and P-deficient (2 μmol/L) algae for up to 35 generations to assess the multigenerational impacts on genome size and nucleus size. Analysis by flow cytometry revealed significant increases in nucleus size for both species as well as genome size for D. magna in response to a low temperature. The degree of endoreplication, measured as cycle value, was species specific and responded to temperature and dietary composition. Under dietary P deficiency, D. magna, but not D. pulex, showed an apparent reduction in haploid genome size (C-value). These genomic responses are unlikely to reflect differences in nucleotide numbers, but rather structural changes affecting fluorochrome binding. While the ultimate and proximate causes of these responses are unknown, they suggest an intriguing potential for genomic responses that merits further research.

  6. Bioremediation efficiency of applying Daphnia magna and submerged plants:A case study in Dishui Lake of Shanghai,China%大型溞引导的沉水植被生态修复对滴水湖水质的净化效果

    Institute of Scientific and Technical Information of China (English)

    霍元子; 何文辉; 罗坤; 王阳阳; 张饮江; 田千桃; 何培民

    2010-01-01

    2007年4月-2008年1月,在滴水湖D港中段长950 m(水量为10000 m~3)的修复区内投放大型潘(Daphnia magna),以滤除水华藻类等颗粒有机物,然后移栽伊乐藻、苦草、轮叶黑藻、光叶眼子菜和菹草等沉水植物,逐月监测水体中总氮(TN)、铵态氮(NH_4~+-N)、硝态氮(NO_3~--N)、亚硝态氮(NO_2~--N)、总磷(TP)、活性磷酸盐(PO_4~(3-)-P)和COD等水质指标,分析沉水植被栽培对滴水湖水体水质的净化效果.结果表明:试验期间,修复区水体TN、TP、NO_3~--N、NO_2~--N、NH_4~+-N、PO_4~(3-)-P和COD显著低于对照区(P<0.01),溶解氧(DO)增加了50.4%,水体透明度(SD)平均在3.4~3.7 m,水质达到国家Ⅱ~Ⅲ类地表水水质标准;2008年3月应用已构建的沉水植被群落对富营养化流水水体水质进行净化试验,7 d后修复区流水水体除BOD外,TN、TP、NO_3~--N、NO_2~--N、NH_4~+-N、PO_4~(3-)-P和COD均显著降低(P<0.01),DO增加了17.98%,SD提高了30 cm.利用大型潘控藻后移栽沉水植物对滴水湖水体水质的净化效果十分显著.

  7. Gene expression and activity of digestive proteases in Daphnia: effects of cyanobacterial protease inhibitors

    Science.gov (United States)

    2010-01-01

    Background The frequency of cyanobacterial blooms has increased worldwide, and these blooms have been claimed to be a major factor leading to the decline of the most important freshwater herbivores, i.e. representatives of the genus Daphnia. This suppression of Daphnia is partly attributed to the presence of biologically active secondary metabolites in cyanobacteria. Among these metabolites, protease inhibitors are found in almost every natural cyanobacterial bloom and have been shown to specifically inhibit Daphnia's digestive proteases in vitro, but to date no physiological responses of these serine proteases to cyanobacterial protease inhibitors in Daphnia have been reported in situ at the protein and genetic levels. Results Nine digestive proteases were detected in D. magna using activity-stained SDS-PAGE. Subsequent analyses by LC-MS/MS and database search led to the identification of respective protease genes. D. magna responded to dietary protease inhibitors by up-regulation of the expression of these respective proteases at the RNA-level and by the induction of new and less sensitive protease isoforms at the protein level. The up-regulation in response to dietary trypsin- and chymotrypsin-inhibitors ranged from 1.4-fold to 25.6-fold. These physiological responses of Daphnia, i.e. up-regulation of protease expression and the induction of isoforms, took place even after feeding on 20% cyanobacterial food for only 24 h. These physiological responses proved to be independent from microcystin effects. Conclusion Here for the first time it was shown in situ that a D. magna clone responds physiologically to dietary cyanobacterial protease inhibitors by phenotypic plasticity of the targets of these specific inhibitors, i.e. Daphnia gut proteases. These regulatory responses are adaptive for D. magna, as they increase the capacity for protein digestion in the presence of dietary protease inhibitors. The type and extent of these responses in protease expression might

  8. Contrasting migration behaviour of Daphnia pulicaria and D. galeata × hyalina, in avoidance of predation by 0+perch (Perca fluviatilis)

    NARCIS (Netherlands)

    Flik, B.J.G.; Vijverberg, J.

    2003-01-01

    In spring and early summer, a small population of the large-bodied Daphnia pulicaria coexists with a much larger population of the medium-sized hybrid Daphnia galeata × hyalina in the epilimnion of Lake Maarsseveen (The Netherlands). When large shoals of juvenile perch (Perca fluviatilis) appear in

  9. Toxicity of new generation flame retardants to Daphnia magna

    NARCIS (Netherlands)

    Waaijers, S.L.; Hartmann, J; Soeter, A.M.; Helmus, R.; Kools, S.A.E.; de Voogt, P.; Admiraal, W.; Parsons, J.R.; Kraak, M.H.S.

    2013-01-01

    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

  10. Effects of Nanosilver on Daphnia magna and Pimephales promelas

    Science.gov (United States)

    The increasing use of nanosilver in consumer products warrants investigation into its toxicity to aquatic organisms. A series of studies were conducted comparing the potency of nanosilver to ionic silver (Ag+) at acute and sublethal levels and to evaluate the likelihood that the ...

  11. The acute toxicity of lead nitrate on Daphnia magna Straus

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-03

    Dec 3, 2008 ... toxic metals in the environment via transfer from natural and/or anthropogenic ... and used as a standard bioindicator organisms for both water and .... dation of water quality requires detailed knowledge of the state of an ...

  12. Conserved Transcription Factors Steer Growth-Related Genomic Programs in Daphnia

    Science.gov (United States)

    Spanier, Katina I.; Jansen, Mieke; Decaestecker, Ellen; Hulselmans, Gert; Becker, Dörthe; Colbourne, John K.; Orsini, Luisa

    2017-01-01

    Abstract Ecological genomics aims to understand the functional association between environmental gradients and the genes underlying adaptive traits. Many genes that are identified by genome-wide screening in ecologically relevant species lack functional annotations. Although gene functions can be inferred from sequence homology, such approaches have limited power. Here, we introduce ecological regulatory genomics by presenting an ontology-free gene prioritization method. Specifically, our method combines transcriptome profiling with high-throughput cis-regulatory sequence analysis in the water fleas Daphnia pulex and Daphnia magna. It screens coexpressed genes for overrepresented DNA motifs that serve as transcription factor binding sites, thereby providing insight into conserved transcription factors and gene regulatory networks shaping the expression profile. We first validated our method, called Daphnia-cisTarget, on a D. pulex heat shock data set, which revealed a network driven by the heat shock factor. Next, we performed RNA-Seq in D. magna exposed to the cyanobacterium Microcystis aeruginosa. Daphnia-cisTarget identified coregulated gene networks that associate with the moulting cycle and potentially regulate life history changes in growth rate and age at maturity. These networks are predicted to be regulated by evolutionary conserved transcription factors such as the homologues of Drosophila Shavenbaby and Grainyhead, nuclear receptors, and a GATA family member. In conclusion, our approach allows prioritising candidate genes in Daphnia without bias towards prior knowledge about functional gene annotation and represents an important step towards exploring the molecular mechanisms of ecological responses in organisms with poorly annotated genomes. PMID:28854641

  13. Evaluation of MWNT toxic effects on daphnia and zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Olasagasti, Maider; Rainieri, Sandra [AZTI-TECNALIA, Parque Tecnologico de Bizkaia 609, 48160 Derio (Spain)], E-mail: srainieri@azti.es; Alvarez, Noelia; Vera, Carolina [INASMET-TECNALIA, Mikeletegi pasealekua, 2, Parque Tecnologico, 20009 San Sebastian (Spain)

    2009-05-01

    Organisms of daphnia (Daphnia magna) and zebrafish (Danio rerio) embryos were exposed to a range of different concentrations of COOH-functionalized MWCNT suspended in an aqueous solution of Tween 20. Immobilization of daphnia and growth retardation, inhibition and malformation of zebrafish embryos were the endpoints tested after 24 and 48 hours. Immobilization of daphnia could be observed from 3 to 16 ppm and an increasing mortality of zebrafish embryo was detected at all the concentration tested. To identify more subtle toxic effects, we took advantage of the extensive information available on the zebrafish genome and monitored by RT-PCR the expression patterns of different zebrafish genes that could act as toxicity bio-markers. At some of the concentrations tested, changes in the expression profiles of the genes examined were detected. Our results suggest that MWCNT could potentially represent a risk to human health and environment, therefore a wider range of concentrations and further testing of this molecules should be carried out to define possible limitations in their use.

  14. Calcium interacts with temperature to influence Daphnia movement rates

    Science.gov (United States)

    Roszell, Jordan; Heyland, Andreas; Fryxell, John M.

    2016-01-01

    Predicting the ecological responses to climate change is particularly challenging, because organisms might be affected simultaneously by the synergistic effects of multiple environmental stressors. Global warming is often accompanied by declining calcium concentration in many freshwater ecosystems. Although there is growing evidence that these changes in water chemistry and thermal conditions can influence ecosystem dynamics, little information is currently available about how these synergistic environmental stressors could influence the behaviour of aquatic organisms. Here, we tested whether the combined effects of calcium and temperature affect movement parameters (average speed, mean turning frequency and mean-squared displacement) of the planktonic Daphnia magna, using a full factorial design and exposing Daphnia individuals to a range of realistic levels of temperature and calcium concentration. We found that movement increased with both temperature and calcium concentration, but temperature effects became considerably weaker when individuals were exposed to calcium levels close to survival limits documented for several Daphnia species, signalling a strong interaction effect. These results support the notion that changes in water chemistry might have as strong an effect as projected changes in temperature on movement rates of Daphnia, suggesting that even sublethal levels of calcium decline could have a considerable impact on the dynamics of freshwater ecosystems. PMID:28083097

  15. Effects of crepuscular photoenvironment on light-induced behavior of Daphnia.

    Science.gov (United States)

    Grover, P B; Miller, R J

    1984-11-01

    Phototactic response rates in the aquatic crustacean Daphnia magna were found to increase greatly when cultured under a lighting regime that included simulation of sunset and sunrise. The changes in intensity and color of the crepuscular periods are known to be the primary stimulus for vertical migrations of many planktonic forms, and may have importance to many other animals as well. The value of this type of lighting to investigators of animal behavior and physiology is discussed.

  16. Ramon Llull's Ars Magna

    DEFF Research Database (Denmark)

    Jensen, Thessa

    2017-01-01

    intelligence and knowledge representation, which seeks to formalise language and knowledge in a way which can be translated into a computer program. And as Fidora’s and Sierra’s [4] anthology Ramon Llull: From the Ars Magna to Artificial Intelligence shows, Llull’s influence and relevance is profound in today......’s work on topics ranging from conceptual graphs and logical analysis, social choice theory and adaptive reasoning to Llull’s influence on Peirce’s pragmatic thinking. Llull is important, even now, on a whole other level. His ethical considera-tions when he wanted to convince people of the one true faith...... Llull: From the Ars Magna to Artificial Intelligence. Barcelona: Artificial Intelligence Research Institute (2011)....

  17. Dietary exposure of Daphnia to microcystins: no in vivo relevance of biotransformation.

    Science.gov (United States)

    Sadler, Thomas; von Elert, Eric

    2014-05-01

    Anthropogenic nutrient input into lakes has contributed to the increased frequency of toxic cyanobacterial blooms. Daphnia populations have been shown to be locally adapted to toxic cyanobacteria and are able to suppress bloom formation; little is known about the physiology behind this phenomenon. Microcystin-LR (MCLR) is the most widespread cyanobacterial toxin, and, based on in vitro experiments, it is assumed that the enzyme glutathione-S-transferase (GST) might act as the first step of detoxification in Daphnia by conjugating MCLR with glutathione. In the present study Daphnia magna was fed a diet of 100% Microcystis aeruginosa PCC7806, a cyanobacterial strain that contains MCLR in high amounts (4.8-5.6 fg cell(-1)), in order to test for a possible conjugation of MCLR with GST in Daphnia in vivo. We used high-resolution LCMS to analyze incubation water, cyanobacterial cells and Daphnia tissue for the presence of MCLR conjugation products as well as unconjugated MCLR. Newly formed conjugation products were detected neither in Daphnia tissue nor in the incubation water. Moreover, the presence of Daphnia led to a decrease in unconjugated MCLR in the cyanobacterial cell fraction due to grazing, in comparison to a control without daphnids, which was well reflected by a similar increase of MCLR in the respective incubation water. As a consequence, the MCLR content did not change due to Daphnia presence within the entire experimental setup. In summary, MCLR ingestion by Daphnia led neither to the formation of conjugation products, nor to a decrease of unconjugated MCLR. GST-mediated conjugation thus seems to be of minor relevance for microcystin (MC) tolerance in Daphnia in vivo. This finding is supported by the fact that GST activity in Daphnia feeding on the MC-containing wildtype or a MC-free mutant of M. aeruginosa PCC7806 revealed an identical increase of specific activity in comparison to a cyanobacteria-free diet. Therefore, the frequently observed induction of

  18. Effects of common-use pesticides on developmental and reproductive processes in Daphnia.

    Science.gov (United States)

    Kashian, Donna R; Dodson, Stanley I

    2002-06-01

    Daphnia magna were evaluated for use as a screen for pesticides that have been demonstrated to have estrogenic (o'p'-DDT, di-n-butyl phthalate, toxaphene), anti-androgenic (p'p-DDE, linuron), thyroid (acetochlor, alachlor, metribuzin), insulin (amitraz) or lutenizing hormone (2,4-D) activity in vertebrates, and to establish daphnid sensitivity to these compounds. Pesticides with unknown effects on vertebrate endocrine systems (chlorosulfuran, cyanazine, diflubenzuron, metolachlor, and diquat) were also evaluated. Compounds were assayed for six days at environmentally relevant concentrations ranging from 0.001 to 100 mirog/L, using female Daphnia and their offspring. Sublethal endpoints included offspring sex (sex determination), clutch size (fecundity), and adult size (growth rate). Toxaphene was the only compound that affected sexual differentiation, increasing male production. Daphnia fecundity declined with exposure to toxaphene, and daphnid growth rates were reduced by acetochlor exposure. Diflubenzuron, o'p'-DDT, and p'p-DDE significantly reduced Daphnia survival. No correlation existed between affected reproductive or developmental processes and specific endocrine systems or subsystems. Results from this study indicate that Daphnia make a good screen for assessing potential environmental impacts but are not a useful indicator of pesticide hormonal activity in vertebrates. This assay consistently detected sublethal but ecologically relevant effects of these pesticides on Daphnia at environmentally relevant concentrations typically below their listed EC50 value.

  19. Telomerase activity and telomere length in Daphnia.

    Science.gov (United States)

    Schumpert, Charles; Nelson, Jacob; Kim, Eunsuk; Dudycha, Jeffry L; Patel, Rekha C

    2015-01-01

    Telomeres, comprised of short repetitive sequences, are essential for genome stability and have been studied in relation to cellular senescence and aging. Telomerase, the enzyme that adds telomeric repeats to chromosome ends, is essential for maintaining the overall telomere length. A lack of telomerase activity in mammalian somatic cells results in progressive shortening of telomeres with each cellular replication event. Mammals exhibit high rates of cell proliferation during embryonic and juvenile stages but very little somatic cell proliferation occurs during adult and senescent stages. The telomere hypothesis of cellular aging states that telomeres serve as an internal mitotic clock and telomere length erosion leads to cellular senescence and eventual cell death. In this report, we have examined telomerase activity, processivity, and telomere length in Daphnia, an organism that grows continuously throughout its life. Similar to insects, Daphnia telomeric repeat sequence was determined to be TTAGG and telomerase products with five-nucleotide periodicity were generated in the telomerase activity assay. We investigated telomerase function and telomere lengths in two closely related ecotypes of Daphnia with divergent lifespans, short-lived D. pulex and long-lived D. pulicaria. Our results indicate that there is no age-dependent decline in telomere length, telomerase activity, or processivity in short-lived D. pulex. On the contrary, a significant age dependent decline in telomere length, telomerase activity and processivity is observed during life span in long-lived D. pulicaria. While providing the first report on characterization of Daphnia telomeres and telomerase activity, our results also indicate that mechanisms other than telomere shortening may be responsible for the strikingly short life span of D. pulex.

  20. Telomerase Activity and Telomere Length in Daphnia

    Science.gov (United States)

    Schumpert, Charles; Nelson, Jacob; Kim, Eunsuk; Dudycha, Jeffry L.; Patel, Rekha C.

    2015-01-01

    Telomeres, comprised of short repetitive sequences, are essential for genome stability and have been studied in relation to cellular senescence and aging. Telomerase, the enzyme that adds telomeric repeats to chromosome ends, is essential for maintaining the overall telomere length. A lack of telomerase activity in mammalian somatic cells results in progressive shortening of telomeres with each cellular replication event. Mammals exhibit high rates of cell proliferation during embryonic and juvenile stages but very little somatic cell proliferation occurs during adult and senescent stages. The telomere hypothesis of cellular aging states that telomeres serve as an internal mitotic clock and telomere length erosion leads to cellular senescence and eventual cell death. In this report, we have examined telomerase activity, processivity, and telomere length in Daphnia, an organism that grows continuously throughout its life. Similar to insects, Daphnia telomeric repeat sequence was determined to be TTAGG and telomerase products with five-nucleotide periodicity were generated in the telomerase activity assay. We investigated telomerase function and telomere lengths in two closely related ecotypes of Daphnia with divergent lifespans, short-lived D. pulex and long-lived D. pulicaria. Our results indicate that there is no age-dependent decline in telomere length, telomerase activity, or processivity in short-lived D. pulex. On the contrary, a significant age dependent decline in telomere length, telomerase activity and processivity is observed during life span in long-lived D. pulicaria. While providing the first report on characterization of Daphnia telomeres and telomerase activity, our results also indicate that mechanisms other than telomere shortening may be responsible for the strikingly short life span of D. pulex. PMID:25962144

  1. Ramon Llull's Ars Magna

    DEFF Research Database (Denmark)

    Jensen, Thessa

    ; conceived and written in the late 13th century by a lay-monk whose life alone would be worth a Hollywood movie. In this paper I will take a brief look at Llull’s life and work, before explaining the four main parts of his Ars Magna. Finally, I will try to give a new perspec-tive on how the Ars Magna still...... might be a viable and valuable approach to understand some of the challenges and possibilities found in computer science and ethics. Vita Llull was born in 1232 in Palma de Mallorca, a melting pot for different cul-tures and religions at the time. Being educated at the king’s court, Llull learned...... the trade of the troubadour as well as reading and writing in Catalan. He became a devout Christian later in life only after he had married. Jesus showed himself to Llull on several occasions, and eventually Llull resumed his rather debauched life and decided to dedicate the rest of his life to three...

  2. Psicosis asociada a megacisterna magna Psychosis associated to megacisterna magna

    Directory of Open Access Journals (Sweden)

    M. Langarica

    2005-04-01

    Full Text Available La megacisterna magna es una malformación de las estructuras de la línea media cerebral, que existe a lo largo de un continuo con la hipoplasia cerebelar (variante de Dandy-Walker y la agenesia cerebelar (síndrome de Dandy-Walker. Actualmente los trastornos psicóticos, y la esquizofrenia en particular, son conceptualizados como trastornos del neurodesarrollo. Presentamos el caso de un paciente con un trastorno psicótico, de tipo delirante, y una megacisterna magna. Se trata del primer caso documentado donde coexiste esta asociación, y se sugiere que tanto el trastorno psicótico como la megacisterna magna pueden ser expresión de la misma anomalía del neurodesarrollo.Megacisterna magna is a developmental malformation of the middle-line brain structures, which exists along a continuum with cerebellum hypoplasia (Dandy-Walker variant and cerebellum agenesia (Dandy-Walker syndrome. Psychotic disorders, and particularly schizophrenia, are now conceptualised as disorders of neurodevelopment. We report on a patient who presented a psychotic disorder (delusional type, and mega cisterna magna. This is the first report of such an association, and it is suggested that both the psychotic disorder and the mega cisterna magna may be the expression of a single underlying neurodevelopment abnormality.

  3. Physiological interaction of Daphnia and Microcystis with regard to cyanobacterial secondary metabolites.

    Science.gov (United States)

    Sadler, Thomas; von Elert, Eric

    2014-11-01

    Cyanobacterial blooms in freshwater ecosystems are a matter of high concern with respect to human health and ecosystem services. Investigations on the role of cyanobacterial secondary metabolites have largely been confined to microcystins, although cyanobacteria produce a huge variety of toxic or inhibitory secondary metabolites. Mass occurrences of toxic cyanobacteria strongly impact freshwater zooplankton communities; especially the unselective filter feeder Daphnia. Daphnids have been shown to successfully suppress bloom formation. However, the opposite situation, i.e. the suppression of Daphnia populations by cyanobacteria can be observed as well. To understand these contradictory findings the elucidation of the underlying physiological mechanisms that help daphnids to cope with cyanotoxins is crucial. We fed Daphnia magna with the cyanobacterium Microcystis aeruginosa PCC7806 for 24h and used high-resolution LCMS analytics to analyze the Microcystis cells, the Daphnia tissue and the surrounding medium in order to investigate the fate of seven investigated cyanobacterial compounds (cyanopeptolins A-C, microcyclamide 7806A and aerucyclamides B-D). For none of these bioactive compounds evidence for biotransformation or biodegradation by Daphnia were found. Instead feeding and subsequent release experiments point at the importance of transport mechanisms in Daphnia with regard to the cyanopeptolins A and C and microcyclamide 7806A. In addition we found hints for new inducible defense mechanism in Microcystis against predation by Daphnia. These putative defense mechanisms include the elevated production of toxic compounds other than microcystins, as could be demonstrated here for aerucyclamide B and D, cyanopoeptolin B and microcyclamide 7806A. Moreover, our data demonstrate the elevated active export of at least one cyanobacterial compound (microcyclamide 7806A) into the surrounding medium as a response to grazer presence, which might constitute an entirely new

  4. Protection against the toxicity of microcystin-LR and cylindrospermopsin in Artemia salina and Daphnia spp. by pre-treatment with cyanobacterial lipopolysaccharide (LPS).

    Science.gov (United States)

    Lindsay, J; Metcalf, J S; Codd, G A

    2006-12-15

    Purified cyanobacterial lipopolysaccharide (LPS) was not acutely toxic to three aquatic invertebrates (Artemia salina, Daphnia magna and Daphnia galeata) in immersion trials. However, pre-exposure (24 h) to 2 ngmL(-1) LPS increased the LC(50) of microcystin-LR significantly in all 3 species. Similar results were observed with A. salina pre-treated with the same concentration of cyanobacterial LPS and subsequently exposed to cylindrospermopsin, increasing the LC(50) by 8. The findings indicate the need to include exposures to defined combinations of cyanotoxins, and in defined sequences, to understand the contributions of individual cyanotoxins in accounting for cyanobacterial toxicity to invertebrates in natural aquatic environments.

  5. Epidemiology of a Daphnia-multiparasite system and its implications for the red queen.

    Directory of Open Access Journals (Sweden)

    Stuart K J R Auld

    Full Text Available The Red Queen hypothesis can explain the maintenance of host and parasite diversity. However, the Red Queen requires genetic specificity for infection risk (i.e., that infection depends on the exact combination of host and parasite genotypes and strongly virulent effects of infection on host fitness. A European crustacean (Daphnia magna--bacterium (Pasteuria ramosa system typifies such specificity and high virulence. We studied the North American host Daphnia dentifera and its natural parasite Pasteuria ramosa, and also found strong genetic specificity for infection success and high virulence. These results suggest that Pasteuria could promote Red Queen dynamics with D. dentifera populations as well. However, the Red Queen might be undermined in this system by selection from a more common yeast parasite (Metschnikowia bicuspidata. Resistance to the yeast did not correlate with resistance to Pasteuria among host genotypes, suggesting that selection by Metschnikowia should proceed relatively independently of selection by Pasteuria.

  6. Juvenile angiofibroma

    Science.gov (United States)

    Nasal tumor; Angiofibroma - juvenile; Benign nasal tumor; Juvenile nasal angiofibroma; JNA ... Juvenile angiofibroma is not very common. It is most often found in adolescent boys. The tumor contains ...

  7. The ecoresponsive genome of Daphnia pulex

    Energy Technology Data Exchange (ETDEWEB)

    Colbourne, John K.; Pfrender, Michael E.; Gilbert, Donald; Thomas, W. Kelley; Tucker, Abraham; Oakley, Todd H.; Tokishita, Shinichi; Aerts, Andrea; Arnold, Georg J.; Basu, Malay Kumar; Bauer, Darren J.; Caceres, Carla E.; Carmel, Liran; Casola, Claudio; Choi, Jeong-Hyeon; Detter, John C.; Dong, Qunfeng; Dusheyko, Serge; Eads, Brian D.; Frohlich, Thomas; Geiler-Samerotte, Kerry A.; Gerlach, Daniel; Hatcher, Phil; Jogdeo, Sanjuro; Krijgsveld, Jeroen; Kriventseva, Evgenia V; Kültz, Dietmar; Laforsch, Christian; Lindquist, Erika; Lopez, Jacqueline; Manak, Robert; Muller, Jean; Pangilinan, Jasmyn; Patwardhan, Rupali P.; Pitluck, Samuel; Pritham, Ellen J.; Rechtsteiner, Andreas; Rho, Mina; Rogozin, Igor B.; Sakarya, Onur; Salamov, Asaf; Schaack, Sarah; Shapiro, Harris; Shiga, Yasuhiro; Skalitzky, Courtney; Smith, Zachary; Souvorov, Alexander; Sung, Way; Tang, Zuojian; Tsuchiya, Dai; Tu, Hank; Vos, Harmjan; Wang, Mei; Wolf, Yuri I.; Yamagata, Hideo; Yamada, Takuji; Ye, Yuzhen; Shaw, Joseph R.; Andrews, Justen; Crease, Teresa J.; Tang, Haixu; Lucas, Susan M.; Robertson, Hugh M.; Bork, Peer; Koonin, Eugene V.; Zdobnov, Evgeny M.; Grigoriev, Igor V.; Lynch, Michael; Boore, Jeffrey L.

    2011-02-04

    This document provides supporting material related to the sequencing of the ecoresponsive genome of Daphnia pulex. This material includes information on materials and methods and supporting text, as well as supplemental figures, tables, and references. The coverage of materials and methods addresses genome sequence, assembly, and mapping to chromosomes, gene inventory, attributes of a compact genome, the origin and preservation of Daphnia pulex genes, implications of Daphnia's genome structure, evolutionary diversification of duplicated genes, functional significance of expanded gene families, and ecoresponsive genes. Supporting text covers chromosome studies, gene homology among Daphnia genomes, micro-RNA and transposable elements and the 46 Daphnia pulex opsins. 36 figures, 50 tables, 183 references.

  8. Transcription patterns of genes encoding four metallothionein homologs in Daphnia pulex exposed to copper and cadmium are time- and homolog-dependent.

    Science.gov (United States)

    Asselman, Jana; Shaw, Joseph R; Glaholt, Stephen P; Colbourne, John K; De Schamphelaere, Karel A C

    2013-10-15

    Metallothioneins are proteins that play an essential role in metal homeostasis and detoxification in nearly all organisms studied to date. Yet discrepancies between outcomes of chronic and acute exposure experiments hamper the understanding of the regulatory mechanisms of their isoforms following metal exposure. Here, we investigated transcriptional differences among four identified homologs (mt1-mt4) in Daphnia pulex exposed across time to copper and cadmium relative to a control. Transcriptional upregulation of mt1 and mt3 was detected on day four following exposure to cadmium, whereas that of mt2 and mt4 was detected on day two and day eight following exposure to copper. These results confirm temporal and metal-specific differences in the transcriptional induction of genes encoding metallothionein homologs upon metal exposure which should be considered in ecotoxicological monitoring programs of metal-contaminated water bodies. Indeed, the mRNA expression patterns observed here illustrate the complex regulatory system associated with metallothioneins, as these patterns are not only dependent on the metal, but also on exposure time and the homolog studied. Further phylogenetic analysis and analysis of regulatory elements in upstream promoter regions revealed a high degree of similarity between metallothionein genes of Daphnia pulex and Daphnia magna, a species belonging to the same genus. These findings, combined with a limited amount of available expression data for D. magna metallothionein genes, tentatively suggest a potential generalization of the metallothionein response system between these Daphnia species. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Study on the Effect of Heavy metals toxicity according to changing Hardness concentration using D.magna

    Science.gov (United States)

    Chun Sang, H.

    2016-12-01

    n order to determine and prevent the number of ecological effects of heavy metals in the materials, we have to accurately measure the heavy metals present in the water-based protection ecosystems and may determine the effects to humans. Heavy metals occurred in the industrial effluent which is a state in which the monitor, based on the emission standards are made by the Ministry of Environment and managed and waste water contained Copper, Zinc, lead, etc. These heavy metals are able to express the toxic effects only when present in the free-ions in the aqueous condition, which appears differently affected by the degree to hardness change in accordance with the season, precipitation. Generally changing hardness concentration can not precisely evaluate toxic effects of heavy metals in the water system. Anderson announced a study on bioassay for heavy metals from industrial waste water using Daphnia magna(Anderson, 1944, 1948). Breukelman published study the resitivity difference for the mercury Chloride(HgCl2). Braudouin(1974) compared the zooplankton(Daphnia sp.) acute toxicity of the different heavy metals and confirmed the sensitivity. Shcherban(1979) presented for toxicity evaluation results for the heavy metal of the Daphnia magna according to different temperature conditions. In the United States Environmental Protection Agency(EPA) established a standard test method for water fleas, managed and supervised water ecosystems, and announced the adoption of a bioassay standard method. This study was performed to evaluate acute inhibition using the Daphnia magna for the biological effect of heavy metal ions in water-based toxicity in the hardness change. Evaluation methods were conducted in EPA Water Quality process test criteria. TU(Toxic Unit), NOEC (No Observable Effect Concentration), LOEC (Lowest Observable Effect Concentration), EC50 (Median Effective Concentration) was calculated by Toxcalc 5.0 Program. Keywords : D. magna, Hardness, Toxic Unit, Heavy metal

  10. Trans-generational effects of parental exposure to ionizing radiation in Daphnia

    Energy Technology Data Exchange (ETDEWEB)

    Sarapultseva, Elena I. [Institute of Nuclear Power Engineering National Research Nuclear University ' MEPhI' - INPE NRNU MEPhI, Studgorodok,1, Obninsk, Kaluga region, 249040 (Russian Federation)

    2014-07-01

    We are currently studying the direct and trans-generational effects of exposure to ionizing radiation on fecundity and reproductive success of the exposed Daphnia magna and their non-exposed progeny. As the long-term survival of species strongly depends on the individual fertility and survival of their offspring, changes in the reproductive process are regarded as one of the most significant sub-lethal effects of environmental pollution. We have recently shown that?-irradiation at doses of 100 and 1000 mGy significantly compromised fecundity and reproductive success of the directly exposed D. magna and their non-exposed first-generation offspring. We have also observed the decrease in the size of the irradiated Daphnia. These effects were also observed among the non-exposed first-generation progeny of irradiated parents, thus implying the manifestation of trans-generational effects in Daphnia. As the compromised fertility was observed among majority of the offspring of irradiated parents, it cannot be attributed to segregation of deleterious mutations induced in the germ line of irradiated parents and is most likely underlined by epigenetic mechanisms. The results of our study also provide further support for the hypothesis of non-targeted effects of ionizing radiation. We have recently shown that compromised viability of irradiated D. magna can be attributed cytotoxic effects of irradiation. Our results suggest that the observed cytotoxic effects are mostly attributed to substantially elevated levels of free-radicals detected in the irradiated parents and their first-generation offspring. It would therefore appear that the compromised viability may be attributed to the cytotoxic effects resulted from epigenetic changes affecting some metabolic pathways involved in detoxification of free-radicals. Additionally we have analyzed more distant progeny of irradiated in doses of 100 and 1000 mGy Daphnia. Some potential mechanisms underlying non-targeted effects

  11. Dermatomyositis (Juvenile)

    Science.gov (United States)

    ... Am A Patient / Caregiver Diseases & Conditions Dermatomyositis (Juvenile) Dermatomyositis (Juvenile) Fast Facts Patients with JDM have varying ... What are common signs and symptoms of juvenile dermatomyositis? The most common signs and symptoms of JDM ...

  12. Retinoschisis (Juvenile)

    Science.gov (United States)

    ... here Home › Eye Conditions Listen Retinoschisis What is Juvenile Retinoschisis? Juvenile retinoschisis is an inherited disease diagnosed in childhood ... degeneration of the retina. What are the symptoms? Juvenile retinoschisis, also known as X-linked retinoschisis, occurs ...

  13. Transcription patterns of genes encoding four metallothionein homologs in Daphnia pulex exposed to copper and cadmium are time- and homolog-dependent

    Energy Technology Data Exchange (ETDEWEB)

    Asselman, Jana, E-mail: jana.asselman@ugent.be [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Ghent (Belgium); Shaw, Joseph R.; Glaholt, Stephen P. [The School of Public and Environmental Affairs, Indiana University, Bloomington, IN (United States); Colbourne, John K. [School of Biosciences, The University of Birmingham, Birmingham (United Kingdom); De Schamphelaere, Karel A.C. [Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Ghent (Belgium)

    2013-10-15

    Highlights: •Transcription patterns of 4 metallothionein isoforms in Daphnia pulex. •Under cadmium and copper stress these patterns are time-dependent. •Under cadmium and copper stress these patterns are homolog-dependent. •The results stress the complex regulation of metallothioneins. -- Abstract: Metallothioneins are proteins that play an essential role in metal homeostasis and detoxification in nearly all organisms studied to date. Yet discrepancies between outcomes of chronic and acute exposure experiments hamper the understanding of the regulatory mechanisms of their isoforms following metal exposure. Here, we investigated transcriptional differences among four identified homologs (mt1–mt4) in Daphnia pulex exposed across time to copper and cadmium relative to a control. Transcriptional upregulation of mt1 and mt3 was detected on day four following exposure to cadmium, whereas that of mt2 and mt4 was detected on day two and day eight following exposure to copper. These results confirm temporal and metal-specific differences in the transcriptional induction of genes encoding metallothionein homologs upon metal exposure which should be considered in ecotoxicological monitoring programs of metal-contaminated water bodies. Indeed, the mRNA expression patterns observed here illustrate the complex regulatory system associated with metallothioneins, as these patterns are not only dependent on the metal, but also on exposure time and the homolog studied. Further phylogenetic analysis and analysis of regulatory elements in upstream promoter regions revealed a high degree of similarity between metallothionein genes of Daphnia pulex and Daphnia magna, a species belonging to the same genus. These findings, combined with a limited amount of available expression data for D. magna metallothionein genes, tentatively suggest a potential generalization of the metallothionein response system between these Daphnia species.

  14. Bacteria-mediated effects of antibiotics on Daphnia nutrition.

    Science.gov (United States)

    Gorokhova, Elena; Rivetti, Claudia; Furuhagen, Sara; Edlund, Anna; Ek, Karin; Breitholtz, Magnus

    2015-05-05

    In polluted environments, contaminant effects may be manifested via both direct toxicity to the host and changes in its microbiota, affecting bacteria-host interactions. In this context, particularly relevant is exposure to antibiotics released into environment. We examined effects of the antibiotic trimethoprim on microbiota of Daphnia magna and concomitant changes in the host feeding. In daphnids exposed to 0.25 mg L(-1) trimethoprim for 24 h, the microbiota was strongly affected, with (1) up to 21-fold decrease in 16S rRNA gene abundance and (2) a shift from balanced communities dominated by Curvibacter, Aquabacterium, and Limnohabitans in controls to significantly lower diversity under dominance of Pelomonas in the exposed animals. Moreover, decreased feeding and digestion was observed in the animals exposed to 0.25-2 mg L(-1) trimethoprim for 48 h and then fed 14C-labeled algae. Whereas the proportion of intact algal cells in the guts increased with increased trimethoprim concentration, ingestion and incorporation rates as well as digestion and incorporation efficiencies decreased significantly. Thus, antibiotics may impact nontarget species via changes in their microbiota leading to compromised nutrition and, ultimately, growth. These bacteria-mediated effects in nontarget organisms may not be unique for antibiotics, but also relevant for environmental pollutants of various nature.

  15. Evolutionary ecotoxicology of pesticide resistance: a case study in Daphnia.

    Science.gov (United States)

    Jansen, Mieke; Coors, Anja; Stoks, Robby; De Meester, Luc

    2011-05-01

    Natural populations that are exposed to pesticides in their environment may at the same time be exposed to natural stressors like parasites and predators, which may interact with pesticide exposure. This may not only impact target pest species but also a wide variety of non-target species. This review reports on a joint research program in the water flea Daphnia magna, a non-target species often used as model organism in ecology and ecotoxicology. The focus is on different aspects that are of key importance to understand the evolutionary ecology of pesticide exposure: (1) the capacity of natural populations to genetically adapt to pesticide exposure (2) the added complexity of synergistic effects caused by simultaneous exposure to natural stressors, and (3) the potential interference of evolutionary costs of adaptation to pesticide exposure. Our results showed that natural populations were able to rapidly evolve resistance to the pesticide carbaryl but at the expense of fitness costs. Individuals selected for carbaryl resistance had higher survival rates when exposed to the pesticide but also a greater susceptibility to the challenge imposed by the bacterial endoparasite Pasteuria ramosa. The evolved resistance to carbaryl was in some cases only expressed in the absence of fish kairomones. Further, it became clear that the responses to both exposure to single and combined stressors was for several life history variables strongly dependent upon past exposure to carbaryl. This indicates that past exposures to pesticides are important and can not be neglected when evaluating responses to current stressors.

  16. Dopamine is a key regulator in the signalling pathway underlying predator-induced defences in Daphnia.

    Science.gov (United States)

    Weiss, Linda C; Leese, Florian; Laforsch, Christian; Tollrian, Ralph

    2015-10-07

    The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation in Daphnia pulex and Daphnia longicephala using an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity. © 2015 The Author(s).

  17. Bacterial epibionts of Daphnia: a potential route for the transfer of dissolved organic carbon in freshwater food webs

    Science.gov (United States)

    Eckert, Ester M; Pernthaler, Jakob

    2014-01-01

    The identification of interacting species and elucidation of their mode of interaction may be crucial to understand ecosystem-level processes. We analysed the activity and identity of bacterial epibionts in cultures of Daphnia galeata and of natural daphnid populations. Epibiotic bacteria incorporated considerable amounts of dissolved organic carbon (DOC), as estimated via uptake of tritiated leucine: three times more tracer was consumed by microbes on a single Daphnia than in 1 ml of lake water. However, there was virtually no incorporation if daphnids were anaesthetised, suggesting that their filtration activity was essential for this process. Microbial DOC uptake could predominantly be assigned to microbes that were located on the filter combs of daphnids, where the passage of water would ensure a continuously high DOC supply. Most of these bacteria were Betaproteobacteria from the genus Limnohabitans. Specifically, we identified a monophyletic cluster harbouring Limnohabitans planktonicus that encompassed sequence types from D. galeata cultures, from the gut of Daphnia magna and from daphnids of Lake Zurich. Our results suggest that the epibiotic growth of bacteria related to Limnohabitans on Daphnia spp. may be a widespread and rather common phenomenon. Moreover, most of the observed DOC flux to Daphnia in fact does not seem to be associated with the crustacean biomass itself but with its epibiotic microflora. The unexplored physical association of daphnids with heterotrophic bacteria may have considerable implications for our understanding of carbon transfer in freshwater food webs, that is, a trophic ‘shortcut' between microbial DOC uptake and predation by fish. PMID:24694716

  18. Acute and chronic toxicity of glyphosate to Daphina magna%草甘膦对大型溞的急性和慢性毒性效应研究

    Institute of Scientific and Technical Information of China (English)

    蔡小宇; 姜锦林; 单正军; 卜元卿; 续卫利; 周洁莲

    2016-01-01

    选取99.5%草甘膦原药,研究其对大型溞的急性毒性和21 d慢性毒性效应,观察其对大型溞生长和繁殖指标的影响。急性毒性试验结果表明,草甘膦对大型溞的48h-EC50为151.057 mg·L-1,其对溞类的毒性为低毒;慢性毒性试验结果表明,草甘膦对大型溞的初次产幼溞时间、产幼溞数量、产幼溞胎数以及存活个体的平均体长都有显著的影响,其中,3.125 mg·L-1的暴露浓度可以显著减少大型溞产幼溞数量和产幼溞胎数。综合考虑各项指标,21 d最低可观测效应浓度(LOEC)值为3.125 mg·L-1,无可观测效应浓度(NOEC)值为1.56 mg·L-1。此外,研究还发现在草甘膦暴露浓度为25 mg·L-1时,可以显著延长大型溞首次产卵时间,但未发现草甘膦暴露对大型溞初次蜕壳时间以及蜕壳次数有何显著性影响。研究结果表明,草甘膦在一定程度上对大型溞的生长和繁殖具有抑制效应。%Glyphosate is widely used in agriculture as a broad spectrum herbicide.With the increasing of application, it’s effects on aquatic organisms have also been widely concerned. 99.5%glyphosate technical was selected to assess the acute toxicity to Daphnia magna and the chronic effects on the growth and reproduction after 21-d exposure.The results of acute toxicity test showed that glyphosate had low acute toxicity against Daphnia magna, the 48h-EC50 was 151.057 mg·L-1. The results of chronic test showed that the first reproduction time, the number of total offspring per female, the number of brood per female and the body length of Daphnia magna were significantly affected when exposure to glyphosate at the concentration of 3.125 mg·L-1, the number of total offspring per female and number of brood per female of Daphnia magna were significantly reduced. Taking into account of each index in this experiment, the 21-d lowest observed effect concen-tration(LOEC)was 3.125 mg·L-1 and the no

  19. Reproduction of Daphnia pulex in a Northern Italy pond

    Directory of Open Access Journals (Sweden)

    Valeria Rossi

    2014-04-01

    Full Text Available This paper reports on the occurrence of Daphnia pulex in a small fishless water body of Northern Italy (Bodrio del pastore III and describes its population dynamics. Bodrio is a typical water body originated by erosion from the old Po river-bed surface. During a three year study (2011-2013, D. pulex population showed an increase in density from spring to early summer, it declined in July-August and did not recover, presumably from ephippia, until the following spring. The seasonal dynamics was related to the species thermal tolerance and to invertebrate predation by Chaoborus that resulted in juvenile high mortality and in adaptive predator-avoidance cyclomorphosis. Seasonal variation was observed in the frequency of individuals, most juveniles, showing neckteeth. D. pulex population reproduces by cyclical parthenogenesis and showed a very early investment in sexual reproduction, independent of population density. Males and ephippial females appeared at the beginning of growth season before the density peak according to a typical feature of Daphnia populations from temporary habitats. This suggests a lower influence of the environmental factors on sex determination compared to populations inhabiting more permanent habitats. Lineages that produce males and ephippial females early in the season had lower growth rate than parthenogenetic ones but may preserve from selection pressure by predators a significant percentage of genetic variation linked to sex allocation so that evolution proceeds toward earlier and increased sexual reproduction. Our results suggest further investigation to verify whether the current population is the last remnant of a once much larger metapopulation eventually reduced by anthropogenic disturbances or if it represents the invasion of North American strains.

  20. Juvenile Scleroderma

    Science.gov (United States)

    Juvenile Scleroderma INTRODUCTION Every parent will experience a moment of panic when told their child has scleroderma. ... in all their family members as well. CONCLUSION Juvenile scleroderma can be unsettling for the child and ...

  1. BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, CORBICULA FLUMINEA, LEPOMIS MACROCHIRUS, AND VIBRO FISCHERI

    Science.gov (United States)

    The research presented here is a continuation of work designed to further the science of available and developing continuous, automated water quality monitors and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system (W...

  2. BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF DAPHNIA MAGNA, CHLORELLA VULGARIS, LEPOMIS MACROCHIRUS, AND VIBRIO FISCHERI TO TOLUENE

    Science.gov (United States)

    The research presented here is a continuation of work designed to further the science of available and developing online toxicity monitors(OTMs) and how they may be most effectively deployed in a watershed management plan and/or water quality early warning system. Source waters o...

  3. Daphnia magna bioassays to detect novel eco-toxicological effects of prioritary and emergent contaminants

    OpenAIRE

    Campos, Bruno

    2014-01-01

    There is increasing evidence that the presence of many emerging pollutants in aquatic ecosystems may have detrimental effects on aquatic biota. Of special concern are those emerging pollutants that may act as putative endocrine disrupters in non-vertebrate species, causing unexpected effects. In chapters 2, 3 and 4, I assessed the effects of two pharmaceuticals belonging to the group of "SSRIs": fluoxetine and fluvoxamine, used to treat depression; and the detergent 4-nonylphenol. SSRIs an...

  4. Avaliação da toxicidade de percloratos em Daphnia magna

    OpenAIRE

    Meyer, Tayvia Liz

    2008-01-01

    A contaminação ambiental provocada por percloratos provém principalmentede acções antropogénicas. Os danos causados pela contaminação química depercloratos ocorrem ao nível ambiental, como no solo e na água, com efeitostóxicos em plantas, animais, mas também ao nível da saúde humana. No Homem, a exposição a perclorato tem um efeito na redução da captação de iodeto pela tiróide (hipertireoidismo), um importante regulador do metabolismohumano. Devido aos níveis altos de oxidação, os perclora...

  5. Mixture toxicity of three toxicants with similar and dissimilar modes of action to Daphnia magna

    DEFF Research Database (Denmark)

    Syberg, K.; Engell-Kofoed, Anders Elleby; Pedersen, H.;

    2008-01-01

    Mixture toxicity of similar- and dissimilar-acting toxicants can be predicted by the models concentration addition (CA) and independent action (IA) using single substance toxicity data. Knowledge of the toxicants mode of action is thus required in order to use the models. In order to test the pre...

  6. Uptake and depuration of three differently functionalized zinc oxide nanoparticles to Daphnia magna

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Winther-Nielsen, Margrete; Baun, Anders

    During the last couple of years the use of nanoparticles (NP) has dramatically increased. Zinc oxide nanoparticles (ZnO NP) have a wide range of applications e.g. in personal care products, paints and semi conductors. However, few studies have so far investigated the ecotoxicity of ZnO NP......O, ZnO-OH, ZnO-C8H17). Characterization included ICP-MS, DLS, BET and TEM. Preliminary results show a fast uptake of ZnO NP (k1=0.11 h-1) and fast depuration (k2=-0.23). In contrast, ZnO-OH did not show significant uptake compared to control. The poster will focus on trends in uptake and depuration...

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

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Winther-Nielsen, M.; Baun, Anders

    2014-01-01

    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...

  8. Efeitos combinados de desreguladores endócrinos em Daphnia magna

    OpenAIRE

    Silva, Poliana Vanessa Monteiro Pinto e

    2011-01-01

    O planeta encontra-se inevitável e irremediávelmente exposto a um cocktail de misturas, afectando assim os sistemas aquáticos bem como o Homem. Os ensaios toxicológicos são o apoio fundamental que a ciência dispõe para a previsão estimada da toxicidade de um composto. Cerca de 70% do planeta é constituido por água, água essa que é consequência da acção de poluentes com um número infindável de compostos. Nos seres humanos, 90% dos poluentes ambientais são absorvidos atravé...

  9. Copper toxicity in relation to surface water-dissolved organic matter: biological effects to Daphnia magna

    NARCIS (Netherlands)

    Kramer, K.J.M.; Jak, R.G.; Hattum, van B.; Hooftman, R.N.; Zwolsman, J.J.G.

    2004-01-01

    Water quality standards for copper are usually stated in total element concentrations. It is known, however, that a major part of the copper can be bound in complexes that are biologically not available. Natural organic matter, such as humic and fulvic acids, are strong complexing agents that may af

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

    NARCIS (Netherlands)

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

    2012-01-01

    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 ecotoxi

  11. Effects of lanthanum and lanthanum-modified clay on growth, survival and reproduction of Daphnia magna

    NARCIS (Netherlands)

    Lürling, M.F.L.L.W.; Tolman, Y.

    2010-01-01

    The novel lanthanum-modified clay water treatment technology (Phoslock) seems very promising in remediation of eutrophied waters. Phoslock is highly efficient in stripping dissolved phosphorous from the water column and in intercepting phosphorous released from the sediments. The active phosphorous-

  12. Toxicogenomic responses of nanotoxicity in Daphnia magna exposed to silver nitrate and coated silver nanoparticles

    Science.gov (United States)

    Applications for silver nanomaterials in consumer products are rapidly expanding, creating an urgent need for toxicological examination of the exposure potential and ecological effects of silver nanoparticles (AgNPs). The integration of genomic techniques into environmental toxic...

  13. Effects of Silver Nanoparticles on Japanese Medaka (Oryzias latipes) and Daphnia magna

    Science.gov (United States)

    The introduction of nanoparticles into a variety of consumer products has raised questions about the potential effects of environmental release, and particularly whether the presence of materials at the nano-scale creates potential risks not associated with the bulk materials. C...

  14. The acute toxicity of selected alkylphenols to young and adult Daphnia magna

    NARCIS (Netherlands)

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

    1998-01-01

    Differences in sensitivity toward toxicants between young and adult individuals in a population are assumed to be primarily associated with their difference in body size. This assumption plays a key role in the modeling of effects of variable concentrations of toxicants on nonhomogeneous

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

    Science.gov (United States)

    This work evaluates the relative contribution of soluble (Ag+) silver and and nano-scale silver particles (n-Ag) and thus addresses an important issue relative to potential ecological risk of n-Ag and of other partially-soluble metal nanoparticles. We used acute to chronic (based...

  16. Accumulation and inactivation of avian influenza virus by the filter feeding invertebrate daphnia magna

    Science.gov (United States)

    The principle mode of avian influenza A virus (AIV) transmission among wild birds is thought to occur via an indirect fecal-oral route, whereby individuals contract the virus from the environment through contact with virus-contaminated water. AIV can remain viable for periods of months to years in w...

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

    NARCIS (Netherlands)

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

    2012-01-01

    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

  18. Passive dosing of pyrethroid insecticides to Daphnia magna: Expressing excess toxicity by chemical activity

    DEFF Research Database (Denmark)

    Nørgaard Schmidt, Stine; Gan, Jay; Kretschmann, A. C.

    2015-01-01

    Pyrethroid insecticides are nerve poisons and used as active ingredients in pesticide mixtures available for household and agriculture. The compounds are hydrophobic, and their strong sorption to organic material may result in decreasing exposure levels during toxicity tests and consequent...

  19. The acute toxicity of selected alkylphenols to young and adult Daphnia magna

    NARCIS (Netherlands)

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

    1998-01-01

    Differences in sensitivity toward toxicants between young and adult individuals in a population are assumed to be primarily associated with their difference in body size. This assumption plays a key role in the modeling of effects of variable concentrations of toxicants on nonhomogeneous populations

  20. Trophic transfer of differently coated zinc oxide nanoparticles using crustaceans (Daphnia magna) and zebrafish (Danio rerio)

    DEFF Research Database (Denmark)

    Skjolding, Lars Michael; Winther-Nielsen, M.; Baun, Anders

    During the last couple of years the use of nanoparticles (NP) has dramatically increased. Zinc oxide nanoparticles (ZnO NP) have a wide range of applications e.g. in personal care products, paints and semi conductors. However, only a limited number of studies have so far investigated...... for in the data treatment. The tested ZnO NP was of same primary size (35 nm) but with different functionalizations (ZnO and ZnO-C8H17). Characterization included ICP-MS, DLS, BET and TEM. Results show a fast uptake of ZnO NP in D. rerio reaching steady state after 5 days of exposure yielding a total body burden...

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

    NARCIS (Netherlands)

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

    2015-01-01

    Abstract 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

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

    NARCIS (Netherlands)

    Faassen, E.J.; Garcia-Altares, M.; Mendes e Mello, M.; Lurling, M.F.L.L.W.

    2015-01-01

    ß-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

  3. Toxicity Identification and Evaluation for the Effluent from Wastewater Treatment Plant in Industrial Complex using D.magna

    Science.gov (United States)

    Lee, S.; Keum, H.; Chun Sang, H.

    2015-12-01

    In recent years, the interests on the impacts of industrial wastewater on aquatic ecosystem have increased with concern about ecosystem protection and human health. Whole effluent toxicity tests are used to monitor toxicity by unknown toxic chemicals as well as conventional pollutants from industrial effluent discharges. This study describes the application of TIE (toxicity identification evaluation) procedures to an acutely toxic effluent from a wastewater treatment plant in industrial complex which was toxic to Daphnia magna. In TIE phase I (characterization step), the toxic effects by heavy metals, organic compounds, oxidants, volatile organic compounds, suspended solids and ammonia were screened and revealed that the source of toxicity is far from these toxicants group. Chemical analysis (TIE phase II) on TDS showed that the concentration of chloride ion (6,900 mg/L) was substantially higher than that predicted from EC50 for D. magna. In confirmation step (TIE phase III), chloride ion was demonstrated to be main toxicant in this effluent by the spiking approach, species sensitivity approach and deletion approach. Calcium, potassium, magnesium, sodium, fluorine, sulfate ion concentration (450, 100, 80, 5,300, 0.66, 2,200mg/L) was not shown toxicity from D. magna. Finally, we concluded that chloride was the most contributing toxicant in the waste water treatment plant. Further research activities are needed for technical support of toxicity identification and evaluation on the various types of wastewater treatment plant discharge in Korea. Keywords : TIE, D. magna, Industrial waste water Acknowledgement This research was supported by a grant (15IFIP-B089908-02) from Plant Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government

  4. Food habits of Juvenile American Shad and dynamics of zooplankton in the lower Columbia River

    Science.gov (United States)

    Haskell, C.A.; Tiffan, K.F.; Rondorf, D.W.

    2006-01-01

    As many as 2.4 million adult American shad annually pass John Day Dam, Columbia River to spawn upriver, yet food web interactions of juvenile shad rearing in John Day Reservoir are unexplored. We collected zooplankton and conducted mid-water trawls in McNary (June-July) and John Day reservoirs (August-November) from 1994 through 1996 during the outmigration of subyearling American shad and Chinook salmon. Juvenile American shad were abundant and represented over 98% of the trawl catch in late summer. The five major taxa collected in zooplankton tows were Bosmina longirostris, Daphnia, cyclopoid cope-pods, rotifers, and calanoid copepods. We evaluated total crustacean zooplankton abundance and Daphnia biomass in relation to water temperature, flow, depth, diel period, and cross-sectional location using multiple regression. Differences in zooplankton abundance were largely due to differences in water temperature and flow. Spatial variation in total zooplankton abundance was observed in McNary Reservoir, but not in John Day Reservoir. Juvenile American shad generally fed on numerically abundant prey, despite being less preferred than larger bodied zooplankton. A decrease in cladoceran abundance and size in August coupled with large percentages of Daphnia in juvenile American shad stomachs indicated heavy planktivory. Smaller juvenile American shad primarily fed on Daphnia in August, but switched to more evasive copepods as the mean size of fish increased and Daphnia abundance declined. Because Daphnia are particularly important prey items for subyearling Chinook salmon in mainstem reservoirs in mid to late summer, alterations in the cladoceran food base is of concern for the management of outmigrating salmonids and other Columbia River fishes. ?? 2006 by the Northwest Scientific Association. All rights reserved.

  5. Uptake, retention and internalization of quantum dots in Daphnia is influenced by particle surface functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Feswick, A., E-mail: afeswick@yahoo.ca [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States); Canadian Rivers Institute, University of New Brunswick, PO Box 5050, Saint John NB, CA (United States); Griffitt, R.J., E-mail: joe.griffitt@usm.edu [Department of Coastal Sciences, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564 (United States); Siebein, K., E-mail: kerry.siebein@nist.gov [Major Analytical Instrumentation Center, University of Florida, PO Box 116400, Gainesville, FL 32611 (United States); Barber, D.S., E-mail: barberd@vetmed.ufl.edu [Center for Environmental and Human Toxicology, University of Florida, PO Box 110885, Gainesville, FL 32611 (United States)

    2013-04-15

    Highlights: ► Daphnia underwent a waterborne exposure of PEG, NH{sub 2} and COOH functionalized quantum dot nanoparticles. ► There was preferential retention of COOH nanoparticles. ► TEM demonstrated that NH{sub 2} and COOH nanoparticles were internalized in cells adjacent to the GI tract. ► This cellular internalization was confirmed using energy dispersive spectroscopy. -- Abstract: Nanomaterials are a diverse group of compounds whose inevitable release into the environment warrants study of the fundamental processes that govern the ingestion, uptake and accumulation in aquatic organisms. Nanomaterials have the ability to transfer to higher trophic levels in aquatic ecosystems, and recent evidence suggests that the surface chemistry of both the nanoparticle and biological membrane can influence uptake kinetics. Therefore, our study investigates the effect of surface functionalization on uptake, internalization and depuration in Daphnia spp. Uncharged (polyethylene glycol; PEG), positively charged (amino-terminated: NH{sub 2}) and negatively charged (carboxyl-modified; COOH) cadmium selenide/zinc sulfide quantum dots were used to monitor ingestion, uptake and depuration of nanometals in Daphnia magna and Ceriodaphnia dubia over 24 h of exposure. These studies demonstrated that particles with higher negative charge (COOH quantum dots)