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Cornelis A M Gestel - One of the best experts on this subject based on the ideXlab platform.
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the use of gene expression to unravel the single and mixture toxicity of abamectin and difenoconazole on survival and reproduction of the springtail folsomia candida
Environmental Pollution, 2019Co-Authors: Cornelis A M Gestel, Livia Pitombeira De Figueiredo, Michiel A Daam, Giulia Mainardi, Janine Marien, Evaldo Luiz Gaeta Espindola, Dick RoelofsAbstract:Abstract Pesticides risk assessments have traditionally focused on the effects on standard parameters, such as mortality, reproduction and development. However, one of the first signs of adverse effects that occur in organisms exposed to stress conditions is an alteration in their genomic expression, which is specific to the type of stress, sensitive to very low contaminant concentrations and responsive in a few hours. The aim of the present study was to evaluate the single and binary mixture toxicity of commercial products of abamectin (Kraft® 36 EC) and difenoconazole (Score® 250 EC) to Folsomia candida. Laboratory toxicity tests were conducted to access the effects of these pesticides on springtail survival, reproduction and gene expression. The reproduction assays gave EC50 and EC10 values, respectively, of 6.3 and 1.4 mg a.s./kg dry soil for abamectin; 1.0 and 0.12 mg a.s./kg dry soil for Kraft® 36 EC; and 54 and 23 mg a.s./kg dry soil for Score® 250 EC. Technical difenoconazole did not have any effect at the concentrations tested. No significant differences in gene expression were found between the abamectin concentrations tested (EC10 and EC50) and the solvent control. Exposure to Kraft® 36 EC, however, significantly induced Cyp6 expression at the EC50 level, while VgR was significantly downregulated at both the EC10 and EC50. Exposure to the simple pesticide mixture of Kraft® 36 EC + Score® 250 EC caused significant up regulation of ABC transporter, and significant down regulation of VgR relative to the controls. GABA receptor also showed significant down-regulation between the EC10 and EC50 mixture treatments. Results of the present study demonstrate that pesticide-induced gene expression effects precede and occur at lower concentrations than organism-level responses. Integrating “omic” endpoints in traditional bioassays may thus be a promising way forward in pesticide toxicity evaluations.
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multigeneration toxicity of imidacloprid and thiacloprid to folsomia candida
Ecotoxicology, 2017Co-Authors: Cornelis A M Gestel, Cláudia De Lima E Silva, Jacco Koekkoek, M H Lamoree, Rudo A. VerweijAbstract:In a recent study, we showed that the springtail Folsomia candida was quite sensitive the neonicotinoid insecticides imidacloprid and thiacloprid. This study aimed at determining the toxicity of both compounds to F. candida following exposure over three generations, in natural LUFA 2.2 standard soil. In the first generation, imidacloprid was more toxic than thiacloprid, with LC50s of 0.44 and 9.0 mg/kg dry soil, respectively and EC50s of 0.29 and 1.5 mg/kg dry soil, respectively. The higher LC50/EC50 ratio suggests that thiacloprid has more effects on reproduction, while imidacloprid shows lethal toxicity to the springtails. In the multigeneration tests, using soil spiked at the start of the first generation exposures, imidacloprid had a consistent effect on survival and reproduction in all three generations, with LC50s and EC50s of 0.21–0.44 and 0.12–0.29 mg/kg dry soil, respectively, while thiacloprid-exposed animals showed clear recovery in the second and third generations (LC50 and EC50 > 3.33 mg/kg dry soil). The latter finding is in agreement with the persistence of imidacloprid and the fast degradation of thiacloprid in the test soil.
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bioaccumulation and toxicity of silver nanoparticles and silver nitrate to the soil arthropod folsomia candida
Ecotoxicology, 2014Co-Authors: Pauline L Waalewijnkool, Kim Klein, Rebeca Mallenco Fornies, Cornelis A M GestelAbstract:The growing use of silver nanoparticles (Ag-NP) triggered an increasing interest in their environmental fate and possible ecotoxicological impacts. To investigate the potential risk of Ag-NP to soil organisms, the springtail Folsomia candida was exposed to Ag-NP (reported diameter size 3–8 nm) and AgNO3 in Lufa 2.2 natural soil for 28 days to determine effects on survival and reproduction. Also, the kinetics of uptake and elimination of Ag were studied for F. candida exposed in Lufa 2.2 soil to Ag-NP (at 168 mg Ag/kg dry soil) and AgNO3 (at 30 and 60 mg Ag/kg dry soil). AgNO3 was toxic with an LC50 was 284 mg Ag/kg dry soil for effects on survival and EC10 and EC50 values of 47.6 and 99.5 mg Ag/kg dry soil, respectively for the effect on reproduction. These values did correspond with porewater concentrations of 0.801, 0.042 and 0.082 mg Ag/l, respectively. No effects on survival and reproduction of Ag-NP were observed up to 673 mg Ag/kg dry soil, although porewater concentration was similar to the EC50 for AgNO3. Exposure to both Ag forms caused a fast uptake of Ag, but the Ag elimination rate was significantly higher for Ag-NP than for AgNO3. Bioaccumulation factor was higher for AgNO3 (on average 5.64) than for Ag-NP (1.12). These findings indicate that silver ions are more toxic than Ag-NP and have a higher potential to accumulate in F. candida.
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Molecular and life-history effects of a natural toxin on herbivorous and non-target soil arthropods
Ecotoxicology, 2012Co-Authors: A. E. Elaine Ommen Kloeke, Cornelis A M Gestel, Bjarne Styrishave, Martin Hansen, Jacintha Ellers, Dick RoelofsAbstract:Natural toxins, such as isothiocyanate (ITC), are harmful secondary metabolites produced by plants. Many natural toxins occur in commercial crops, yet their possible negative repercussions on especially non-target soil organisms are largely unknown. This study examined life-history and gene transcriptional responses to 2-phenylethyl ITC on two soil arthropod species: Folsomia candida and Protaphorura fimata . To that end the standardized ISO guideline for ecotoxicological tests and a microarray for F. candida were used. The dissipation of 2-phenylethyl ITC in natural soil was investigated using GC-MS/MS for quantification. Half-lives, tested at four concentration levels in natural soil, were on average 16 h with biodegradation as the plausible main removal process. Regardless, toxic effects on reproduction were shown for F. candida and P. fimata , with EC50 values of around 11.5 nmol/g soil illustrating the toxic character of this compound. Gene expression profiles revealed the importance of fatty acid metabolism at low exposure concentrations (EC10), which is associated with the lipophilic nature of 2-phenylethyl ITC. At higher concentrations (EC50) gene expression became more ubiquitous with over-expression of especially stress-related genes and sugar metabolism. The regulation of a gene encoding a precursor of follistatin, furthermore, implied the inhibition of reproduction and may be an important molecular target that can be linked to the observed adverse effect of life-history traits.
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toxicity of copper to the collembolan folsomia fimetaria in relation to the age of soil contamination
Ecotoxicology and Environmental Safety, 2001Co-Authors: Marianne Bruus Pedersen, Cornelis A M GestelAbstract:Abstract The toxicity of copper to the collembolan Folsomia fimetaria L. was studied in soil incubated with copper sulfate for different periods before the introduction of collembolans, to assess the effect of aging of contamination on the toxicity of copper. Adult survival, reproduction, and juvenile size were assessed. No clear influence of differences in contamination age was detected. The data were compared with results from a study performed in soil sampled at an old copper-contaminated site. Large differences in effects existed between spiked soil and field soil when concentrations were expressed on the basis of total soil copper concentrations. EC10 and EC50 values for reproduction in spiked soil were ca. 700 and 1400 mg Cu/kg soil, whereas no effects were found in field soil at copper concentrations up to 2500 mg/kg. Most of the differences disappeared when effects were expressed as a function of 0.01 M CaCl2-extractable soil copper. the lack of effects in field soil could be explained from the fact that in this field soil the CaCl2-extractable concentration was never higher than one-third of the EC50 estimated for tests in the laboratory spiked soils.
Dick Roelofs - One of the best experts on this subject based on the ideXlab platform.
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the use of gene expression to unravel the single and mixture toxicity of abamectin and difenoconazole on survival and reproduction of the springtail folsomia candida
Environmental Pollution, 2019Co-Authors: Cornelis A M Gestel, Livia Pitombeira De Figueiredo, Michiel A Daam, Giulia Mainardi, Janine Marien, Evaldo Luiz Gaeta Espindola, Dick RoelofsAbstract:Abstract Pesticides risk assessments have traditionally focused on the effects on standard parameters, such as mortality, reproduction and development. However, one of the first signs of adverse effects that occur in organisms exposed to stress conditions is an alteration in their genomic expression, which is specific to the type of stress, sensitive to very low contaminant concentrations and responsive in a few hours. The aim of the present study was to evaluate the single and binary mixture toxicity of commercial products of abamectin (Kraft® 36 EC) and difenoconazole (Score® 250 EC) to Folsomia candida. Laboratory toxicity tests were conducted to access the effects of these pesticides on springtail survival, reproduction and gene expression. The reproduction assays gave EC50 and EC10 values, respectively, of 6.3 and 1.4 mg a.s./kg dry soil for abamectin; 1.0 and 0.12 mg a.s./kg dry soil for Kraft® 36 EC; and 54 and 23 mg a.s./kg dry soil for Score® 250 EC. Technical difenoconazole did not have any effect at the concentrations tested. No significant differences in gene expression were found between the abamectin concentrations tested (EC10 and EC50) and the solvent control. Exposure to Kraft® 36 EC, however, significantly induced Cyp6 expression at the EC50 level, while VgR was significantly downregulated at both the EC10 and EC50. Exposure to the simple pesticide mixture of Kraft® 36 EC + Score® 250 EC caused significant up regulation of ABC transporter, and significant down regulation of VgR relative to the controls. GABA receptor also showed significant down-regulation between the EC10 and EC50 mixture treatments. Results of the present study demonstrate that pesticide-induced gene expression effects precede and occur at lower concentrations than organism-level responses. Integrating “omic” endpoints in traditional bioassays may thus be a promising way forward in pesticide toxicity evaluations.
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Molecular and life-history effects of a natural toxin on herbivorous and non-target soil arthropods
Ecotoxicology, 2012Co-Authors: A. E. Elaine Ommen Kloeke, Cornelis A M Gestel, Bjarne Styrishave, Martin Hansen, Jacintha Ellers, Dick RoelofsAbstract:Natural toxins, such as isothiocyanate (ITC), are harmful secondary metabolites produced by plants. Many natural toxins occur in commercial crops, yet their possible negative repercussions on especially non-target soil organisms are largely unknown. This study examined life-history and gene transcriptional responses to 2-phenylethyl ITC on two soil arthropod species: Folsomia candida and Protaphorura fimata . To that end the standardized ISO guideline for ecotoxicological tests and a microarray for F. candida were used. The dissipation of 2-phenylethyl ITC in natural soil was investigated using GC-MS/MS for quantification. Half-lives, tested at four concentration levels in natural soil, were on average 16 h with biodegradation as the plausible main removal process. Regardless, toxic effects on reproduction were shown for F. candida and P. fimata , with EC50 values of around 11.5 nmol/g soil illustrating the toxic character of this compound. Gene expression profiles revealed the importance of fatty acid metabolism at low exposure concentrations (EC10), which is associated with the lipophilic nature of 2-phenylethyl ITC. At higher concentrations (EC50) gene expression became more ubiquitous with over-expression of especially stress-related genes and sugar metabolism. The regulation of a gene encoding a precursor of follistatin, furthermore, implied the inhibition of reproduction and may be an important molecular target that can be linked to the observed adverse effect of life-history traits.
Marc Van Ranst - One of the best experts on this subject based on the ideXlab platform.
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plant lectins are potent inhibitors of coronaviruses by interfering with two targets in the viral replication cycle
Antiviral Research, 2007Co-Authors: Els Keyaerts, Leen Vijgen, Herman Egberink, Jan Balzarini, Christophe Pannecouque, Els J M Van Damme, Willy J. Peumans, Marc Van RanstAbstract:We describe the antiviral activity of plant lectins with specificity for different glycan structures against the severe acute respiratory syndrome coronavirus (SARS-CoV) and the feline infectious peritonitis virus (FIPV) in vitro. The SARS-CoV emerged in 2002 as an important cause of severe lower respiratory tract infection in humans, and FIPV infection causes a chronic and often fatal peritonitis in cats. A unique collection of 33 plant lectins with different specificities were evaluated. The plant lectins possessed marked antiviral properties against both coronaviruses with EC50 values in the lower microgram/ml range (middle nanomolar range), being non-toxic (CC50) at 50–100 μg/ml. The strongest anti-coronavirus activity was found predominantly among the mannose-binding lectins. In addition, a number of galactose-, N-acetylgalactosamine-, glucose-, and N-acetylglucosamine-specific plant agglutinines exhibited anti-coronaviral activity. A significant correlation (with an r-value of 0.70) between the EC50 values of the 10 mannose-specific plant lectins effective against the two coronaviruses was found. In contrast, little correlation was seen between the activity of other types of lectins. Two targets of possible antiviral intervention were identified in the replication cycle of SARS-CoV. The first target is located early in the replication cycle, most probably viral attachment, and the second target is located at the end of the infectious virus cycle.
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Plant lectins are potent inhibitors of coronaviruses by interfering with two targets in the viral replication cycle
Antiviral Research, 2007Co-Authors: Els Keyaerts, Leen Vijgen, Herman Egberink, Jan Balzarini, Christophe Pannecouque, Els J M Van Damme, Willy J. Peumans, Marc Van RanstAbstract:We describe the antiviral activity of plant lectins with specificity for different glycan structures against the severe acute respiratory syndrome coronavirus (SARS-CoV) and the feline infectious peritonitis virus (FIPV) in vitro. The SARS-CoV emerged in 2002 as an important cause of severe lower respiratory tract infection in humans, and FIPV infection causes a chronic and often fatal peritonitis in cats. A unique collection of 33 plant lectins with different specificities were evaluated. The plant lectins possessed marked antiviral properties against both coronaviruses with EC50 values in the lower microgram/ml range (middle nanomolar range), being non-toxic (CC50) at 50–100g/ml. The strongest anti-coronavirus activity was found predominantly among the mannose-binding lectins. In addition, a number of galactose-, N-acetylgalactosamine-, glucose-, and N-acetylglucosamine-specific plant agglutinines exhibited anti-coronaviral activity. A significant correlation (with an r-value of 0.70) between the EC50 values of the 10 mannose-specific plant lectins effective against the two coronaviruses was found. In contrast, little correlation was seen between the activity of other types of lectins. Two targets of possible antiviral intervention were identified in the replication cycle of SARS-CoV. The first target is located early in the replication cycle, most probably viral attachment, and the second target is located at the end of the infectious virus cycle. © 2007 Elsevier B.V. All rights reserved.
Seungyun Baik - One of the best experts on this subject based on the ideXlab platform.
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investigation of the synergistic toxicity of binary mixtures of pesticides and pharmaceuticals on aliivibrio fischeri in major river basins in south korea
International Journal of Environmental Research and Public Health, 2019Co-Authors: Inhyuk Baek, Seungyun BaikAbstract:This work introduces the potential synergistic toxicity of binary mixtures of pesticides and pharmaceuticals, which have been detected in substantial amounts in major river basins in South Korea. Different dose-response curve functions were employed in each experimental toxicity dataset for Aliivibrio fischeri. We tested the toxicity of 30 binary mixtures at two effect concentrations: high effect concentration [EC50] and low effect concentration (EC10) ranges. Thus, the toxicological interactions were evaluated at 60 effected concentration data points in total and based on model deviation ratios (MDRs) between predicted and observed toxicity values (e.g., three types of combined effects: synergistic (MDR > 2), additive (0.5 ≤ MDR ≤ 2), and antagonistic (MDR < 0.5)). From the 60 data points, MDRs could not be applied to 17 points, since their toxicities could not be measured. The result showed 48%-additive (n = 20), 40%-antagonistic (n = 17), and 12%-synergistic (n = 6) toxicity effects from 43 binaries (excluding the 17 combinations without MDRs). In this study, EC10 ratio mixtures at a low overall effect range showed a general tendency to have more synergistic effects than the EC50 ratio mixtures at a high effect range. We also found an inversion phenomenon, which detected three binaries of the combination of synergism at low concentrations and additive antagonism at high concentrations.
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Investigation of the Synergistic Toxicity of Binary Mixtures of Pesticides and Pharmaceuticals on Aliivibrio fischeri in Major River Basins in South Korea
2018Co-Authors: Inhyuk Baek, Seungyun BaikAbstract:This work introduced the potential synergistic toxicity of binary mixtures of pesticides and pharmaceuticals, which have been substantially detected in major river basins in South Korea. Different dose-response curve functions were employed in each experimental toxicity dataset for Aliivibrio fischeri. We tested the toxicity of 30 binary mixtures at two effect concentrations: high effect concentration [EC50] and low effect concentration [EC10] ranges. Thus, the toxicological interactions were evaluated at 60 effected concentration data points in total and based on model deviation ratios (MDRs) between predicted and observed toxicity values (e.g., three types of combined effects: synergistic (MDR > 2), additive (0.5 ≤ MDR ≤ 2), and antagonistic (MDR < 0.5)). From the 60 data points, MDRs could not be applied to 17 points, since their toxicities could not be measured. The result showed 48 %-additive (n = 20), 40 %-antagonistic (n = 17), and 12 %-synergistic (n = 6) toxicity effects from 43 binaries (excluding the 17 combinations without MDRs). In this study, EC10 ratio mixtures at a low overall effect range showed a general tendency to have more synergistic effects than the EC50 ratio mixtures at a high effect range. We also found an inversion phenomenon, which detected three binaries of the combination of synergism at low concentrations and additive antagonism at high concentrations.
Pier Francesco Ghetti - One of the best experts on this subject based on the ideXlab platform.
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sensitivity limits and EC50 values of the vibrio fischeri test for organic micropollutants in natural and spiked extracts from sediments
Environmental Toxicology and Chemistry, 1998Co-Authors: Michela Salizzato, Valentina Bertato, Bruno Pavoni, Anna Volpi Ghirardini, Pier Francesco GhettiAbstract:Chemical analyses and bioassays were used in conjunction to assess the quality of sediments of the Venice lagoon. Organic micropollutants (polycyclic aromatic hydrocarbons [PAHs] polychlorinated biphenyls [PCBs], and chlorinated pesticides) were extracted from sediment samples and analyzed by gas chromatography after fractionation into classes of compounds. The Vibrio fischeri test was used to assess the acute toxicity of sediment extracts. The test was applied to organic extracts before cleanup and to extracts purified from sulfur and fractionated into single classes of compounds. Extracts before purification were much more toxic than single fractions. In particular, sulfur was toxic to V. fischeri. For PAHs and PCBs the 50% effective concentration (EC50) and EC20 values were determined using natural and spiked extracts (EC50 = 0.5 μg/ml and 1.4 μg/ml, respectively; EC20 = 0.13 μg/ml and 0.17 μg/ml). Sensitivity limits of the method for these compounds were also estimated as was an EC50 value of elemental sulfur dissolved in ethanol (0.022 μg/ml). A mathematical model was used to fit the concentration–response data to a sigmoid curve.