The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Odete Rocha - One of the best experts on this subject based on the ideXlab platform.
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The use of PCR-RFLP to genetically distinguish the morphologically close species: Ceriodaphnia dubia Richard, 1894 and Ceriodaphnia silvestrii Daday, 1902 (Crustacea Cladocera)
Brazilian Journal of Biology, 2010Co-Authors: M. J. Abreu, Odete Rocha, Maria José Dos Santos-wisniewski, Tereza Cristina OrlandoAbstract:The cladocerans are important components of planktonic and benthic freshwater and good indicators of the trophic state of water bodies. The morphological taxonomy of many species of Cladocera is considered complex with minor differences separating some species. Nowadays, molecular techniques provide a powerful tool to identify and classify different taxonomical levels, using mainly ribosomal RNA genes (rRNA) as molecular markers. In the present work we performed PCR-RFLP to separate Ceriodaphnia dubia, an exotic species in Brazil and the native species Ceriodaphnia silvestrii, widely distributed in Brazilian freshwater. The RFLP analysis of the ITS1-5.8S-ITS2 region of rRNA genes showed to be different between C. dubia and C. silvestrii when using enzymes EcoRI, ApaI and SalI. Thus, the ITS1-5.8S-ITS2 region proved to be a useful molecular marker to differentiate the studied Ceriodaphnia species, which makes the task easier of telling apart species that are morphologically very similar. Also, this methodology might be interesting in determining the distribution of the exotic species C. dubia in Brazilian freshwaters, particularly in cases when C. dubia occurs in the absence of C. silvestrii, a particularly difficult task for ecologists who are not taxonomy specialists.
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predation on Ceriodaphnia cornuta and brachionus calyciflorus by two mesocyclops species coexisting in barra bonita reservoir sp brazil
Hydrobiologia, 1990Co-Authors: T Matsumuratundisi, Arnola C Rietzler, José Galizia Tundisi, Evaldo Luiz Gaeta Espindola, Odete RochaAbstract:Feeding experiments with two species of carnivorous copepod, Mesocyclops longisetus (Thiebaud) and Mesocyclops kieferi Van de Velde from Barra Bonita, a eutrophic reservoir in Sao Paulo, Brasil, were performed using two common types of prey: Ceriodaphnia cornuta, a cladoceran, with a mean body length of 464 µm (including spines) or 393 µm (without spines), and Brachionus calyciflorus, a rotifer with a mean body length of 350 µm (including spines) or 279 µm (without spines).
Brian D. Moffat - One of the best experts on this subject based on the ideXlab platform.
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A 2-d Life cycle test with the rotifer Brachionus calyciflorus
Environmental Toxicology and Chemistry, 1992Co-Authors: Terry W. Snell, Brian D. MoffatAbstract:A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly
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a 2 d life cycle test with the rotifer brachionus calyciflorus
Environmental Toxicology and Chemistry, 1992Co-Authors: Terry W. Snell, Brian D. MoffatAbstract:A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly <10%. The comparative sensitivity of the rotifer life cycle test is not yet fully characterized, but for the five compounds compared in both Ceriodaphnia and Brachionus, the chronic values of four were within a factor of six of one another. At the chronic value concentrations of 11 toxicants tested in rotifers, there was on average a 33% reduction in r as compared to controls.
Ferne B Winborne - One of the best experts on this subject based on the ideXlab platform.
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comparison of measured instream biological responses with responses predicted using the Ceriodaphnia dubia chronic toxicity test
Environmental Toxicology and Chemistry, 1990Co-Authors: Kenneth W Eagleson, L.w. Ausley, David L Lenat, Ferne B WinborneAbstract:Instream toxicity was predicted with whole effluent toxicity tests. These results were then compared to the observed instream response of the aquatic community. Forty-three comparisons were conducted in freshwater flowing systems using Ceriodaphnia dubia chronic toxicity test procedures and standardized qualitative sampling of benthic macroinvertebrates. In 88% of the comparisons there was agreement between both measures. These data suggest that the use of effluent toxicity testing results as a regulatory tool is effective and appropriate. Comparisons used whole effluent toxicity limitations similar to those being written in North Carolina's NPDES permits for discharge to surface waters.
Terry W. Snell - One of the best experts on this subject based on the ideXlab platform.
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A 2-d Life cycle test with the rotifer Brachionus calyciflorus
Environmental Toxicology and Chemistry, 1992Co-Authors: Terry W. Snell, Brian D. MoffatAbstract:A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly
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a 2 d life cycle test with the rotifer brachionus calyciflorus
Environmental Toxicology and Chemistry, 1992Co-Authors: Terry W. Snell, Brian D. MoffatAbstract:A 2-d life cycle test using the freshwater rotifer Brachionus calyciflorus is described for assessing chronic toxicity. The end point for this test is r, the intrinsic rate of increase, which has high ecological relevancy because it measures the growth potential of a population. The test is multi-generational because two-thirds of the reproduction is attributable to parental females and one-third to F1 females. Despite its brevity, the rotifer test includes 30% more of test animal life span than a 7-d Ceriodaphnia test. Test protocol is simple to execute, with test animals obtained by hatching cysts and the algal food obtained from petri dish cultures. A small volume of test solution (120 ml) is required for a test, making the rotifer test potentially useful for conducting chronic toxicity identification evaluations (TIEs), in which test solution availability and exposure duration can be important. Analysis of the person hours required to execute a test shows that the rotifer test requires 70% less effort than 7-d Ceriodaphnia or fathead minnow tests. The simplicity of the rotifer test contributes to its excellent reproducibility; C.V.s are commonly <10%. The comparative sensitivity of the rotifer life cycle test is not yet fully characterized, but for the five compounds compared in both Ceriodaphnia and Brachionus, the chronic values of four were within a factor of six of one another. At the chronic value concentrations of 11 toxicants tested in rotifers, there was on average a 33% reduction in r as compared to controls.
T.l. Pollock - One of the best experts on this subject based on the ideXlab platform.
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Effects of food and water quality on culturing of Ceriodaphnia dubia
Environmental Toxicology and Chemistry, 1992Co-Authors: J.d. Cooney, G.m. Degraeve, E.l. Moore, W.d. Palmer, T.l. PollockAbstract:The U.S. Environmental Protection Agency (EPA) has developed a 7-d test to evaluate effluent effects on Ceriodaphnia dubia survival and reproduction. Several foods have been used to culture and test Ceriodaphnia dubia in both laboratory waters and surface waters with variable results. This study's objective was to evaluate effects of eight diets on survival and reproduction of Ceriodaphnia dubia in hard reconstituted water (HRW); HRW was used alone or supplemented with bacteria or selenium to determine whether their addition would improve survival and reproduction. Diets consisted of yeast, trout food (TF), yeast/trout food/Cerophylc (YTC), Selenastrum capricornutum, Ankistrodesmus convolutus, Chlamydomonas reinhardii, Selenastrum capricornutum plus TF, and Selenastrum capricornutum plus YTC. Screening tests in HRW with each diet (at several levels) were first used to rank diets; diets with high survival (®80% at 14 d) and reproduction (®3 young per female per reproductive day) were further evaluated in multigeneration feeding tests. Finally, diets yielding high survival and reproduction in HRW were evaluated in surface and well water to verify adequacy in waters of differing composition and quality. Yeast, trout food, YTC, Selenastrum capricornutum, Ankistrodesmus convolutus, or Chlamydomonas reinhardii used alone were unacceptable for long-term culturing in HRW under test conditions used in this project. Success of the EPA's recommended food, YTC, was dependent on water, with worst results in HRW. The addition of selenium and bacteria to the HRW did not consistently improve either survival or reproduction of Ceriodaphnia dubia in the diet tests. Some of the diet test results were confounded by the use of batches of HRW that periodically contained some unidentified components that were toxic to Ceriodaphnia dubia. Both Selenastrum capricornutum plus TF and Selenastrum capricornutum plus YTC were acceptable for culturing with high survival and reproduction.
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Effects of environmental and experimental design factors on culturing and toxicity testing of Ceriodaphnia dubia
Environmental Toxicology and Chemistry, 1992Co-Authors: J.d. Cooney, G.m. Degraeve, E.l. Moore, T.l. Pollock, B.j. Lenoble, G.j. SmithAbstract:EPA has developed a 7-day toxicity test to evaluate effects of effluents on Ceriodaphnia dubia survival and reproduction. This study evaluated effects of laboratory conditions and culturing and tests procedures on Ceriodaphnia survival and reproduction. Temperature, food concentration, chamber size, solution renewal frequency, light quality, illumination, photoperiod, water type, and test organism age were evaluated to determine how these various factors affected individual culturing success and acceptibility and reproducibility of toxicity test results. Test conditions proposed by EPA were evaluated by varying individual environmental or experimental design conditions to determine a range of responses for survival and reproduction under controlled conditions, both with and without a reference toxicant. For those conditions not specified by EPA (e.g., water hardness, light quality), a commonly used range of conditions was evaluated. 19 refs., 4 tabs.
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variability in the performance of the 7 d Ceriodaphnia dubia survival and reproduction test an intra and interlaboratory study
Environmental Toxicology and Chemistry, 1992Co-Authors: G.m. Degraeve, J.d. Cooney, T.l. Pollock, B.h. Marsh, N.g. ReichenbachAbstract:The U.S. Environmental Protection Agency (EPA) has developed a 7-day Ceriodaphnia dubia survival and reproduction test for measuring the toxicity of effluents. This study evaluated the ease of performance and the intra- and interlaboratory variability of this 7-d test, using two reference toxicants (sodium chloride and potassium dichromate), two pulp and paper effluents, and two utility effluents Eleven different laboratories, representing academia, private industry, contractors, and the state EPA and federal EPA, participated in the study. The reference toxicants were tested twice during two separate test periods, and each industrial effluent was tested once. Using the EPA's criteria for a successful test (®80% survival and ® 15 young per female in controls), 56% of the 116 planned tests were completed as valid tests. Most tests were invalid because the laboratories were unable to initiate the tests successfully or because control survival was <80%. Seventy-eight percent of the tests that were initiated were successfully completed. Reproduction no-observed-effect-concentration (NOEC) values were generally somewhat lower than those for survival but had greater variability than survival NOEC values. The interlaboratory variability of the survival (LC50) and reproduction (IC50) results, expressed as the C V., ranged between 29.8 and 30.8% and between 28.9 and 39.0%, respectively. The study demonstrated that about half (56%) of the laboratories participating in the study were able to routinely complete the test successfully. Some of the laboratories experienced with other effluent toxicity tests were less prepared to complete this test successfully. Overall, the variability of the 7-d Ceriodaphnia tests that were completed was similar to the variability observed with other toxicity tests and with analytical chemistry measurements of environmental samples.