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Bart S, Short S, Jager T, Eagles EJ, Robinson A, Badder C, Lahive E, Spurgeon DJ, Ashauer R. How to analyse and account for interactions in mixture toxicity with toxicokinetic-toxicodynamic models. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 843:157048. [PMID: 35779734 DOI: 10.1016/j.scitotenv.2022.157048] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 06/25/2022] [Indexed: 05/28/2023]
Abstract
The assessment of chemical mixture toxicity is one of the major challenges in ecotoxicology. Chemicals can interact, leading to more or less effects than expected, commonly named synergism and antagonism respectively. The classic ad hoc approach for the assessment of mixture effects is based on dose-response curves at a single time point, and is limited to identifying a mixture interaction but cannot provide predictions for untested exposure durations, nor for scenarios where exposure varies in time. We here propose a new approach using toxicokinetic-toxicodynamic modelling: The General Unified Threshold model of Survival (GUTS) framework, recently extended for mixture toxicity assessment. We designed a dedicated mechanistic interaction module coupled with the GUTS mixture model to i) identify interactions, ii) test hypotheses to identify which chemical is likely responsible for the interaction, and finally iii) simulate and predict the effect of synergistic and antagonistic mixtures. We tested the modelling approach experimentally with two species (Enchytraeus crypticus and Mamestra brassicae) exposed to different potentially synergistic mixtures (composed of: prochloraz, imidacloprid, cypermethrin, azoxystrobin, chlorothalonil, and chlorpyrifos). Furthermore, we also tested the model with previously published experimental data on two other species (Bombus terrestris and Daphnia magna) exposed to pesticide mixtures (clothianidin, propiconazole, dimethoate, imidacloprid and thiacloprid) found to be synergistic or antagonistic with the classic approach. The results showed an accurate simulation of synergistic and antagonistic effects for the different tested species and mixtures. This modelling approach can identify interactions accounting for the entire time of exposure, and not only at one time point as in the classic approach, and provides predictions of the mixture effect for untested mixture exposure scenarios, including those with time-variable mixture composition.
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Affiliation(s)
- Sylvain Bart
- Department of Environment and Geography, University of York, Heslington, York YO10 5NG, UK; UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; MO-ECO(2) (Modelling and data analyses for ecology and ecotoxicology), Paris, France.
| | - Stephen Short
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff CF10 3TL, UK
| | | | - Emily J Eagles
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Alex Robinson
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Claire Badder
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK; Cardiff School of Biosciences, BIOSI 1, University of Cardiff, P.O. Box 915, Cardiff CF10 3TL, UK
| | - Elma Lahive
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - David J Spurgeon
- UK Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford, Oxfordshire OX10 8BB, UK
| | - Roman Ashauer
- Department of Environment and Geography, University of York, Heslington, York YO10 5NG, UK; Syngenta Crop Protection AG, Basel, Switzerland
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Kulakova AM, Khrenova MG, Nemukhin AV. [Molecular mechanism of chromogenic substrate hydrolysis in the active site of human carboxylesterase-1]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2021; 67:300-305. [PMID: 34142538 DOI: 10.18097/pbmc20216703300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Human carboxylesterases are involved in the protective processes of detoxification during the hydrolytic metabolism of xenobiotics. Knowledge of the molecular mechanisms of substrates hydrolysis in the enzymes active site is necessary for the rational drug design. In this work, the molecular mechanism of the hydrolysis reaction of para-nitrophenyl acetate in the active site of human carboxylesterase was determined using modern methods of molecular modeling. According to the combined method of quantum mechanics/molecular mechanics calculations, the chemical reaction occurs within four elementary steps, including two steps of the acylation stage, and two steps of the deacylation stage. All elementary steps have low energy barriers, with the gradual lowering of the intermediate energies that stimulates reaction in the forward direction. The molecular docking was used to estimate the binding constants of the enzyme-substrate complex and the dissociation constant of enzyme-product complexes. The effective kinetic parameters of the enzymatic hydrolysis in the active site of carboxylesterase are determined by numerical solution of the differential kinetic equations.
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Affiliation(s)
- A M Kulakova
- Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia
| | - M G Khrenova
- Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia; Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Moscow, Russia
| | - A V Nemukhin
- Lomonosov Moscow State University, Department of Chemistry, Moscow, Russia; Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
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Zhao S, Wesseling S, Spenkelink B, Rietjens IMCM. Physiologically based kinetic modelling based prediction of in vivo rat and human acetylcholinesterase (AChE) inhibition upon exposure to diazinon. Arch Toxicol 2021; 95:1573-1593. [PMID: 33715020 PMCID: PMC8113213 DOI: 10.1007/s00204-021-03015-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 02/25/2021] [Indexed: 01/30/2023]
Abstract
The present study predicts in vivo human and rat red blood cell (RBC) acetylcholinesterase (AChE) inhibition upon diazinon (DZN) exposure using physiological based kinetic (PBK) modelling-facilitated reverse dosimetry. Due to the fact that both DZN and its oxon metabolite diazoxon (DZO) can inhibit AChE, a toxic equivalency factor (TEF) was included in the PBK model to combine the effect of DZN and DZO when predicting in vivo AChE inhibition. The PBK models were defined based on kinetic constants derived from in vitro incubations with liver fractions or plasma of rat and human, and were used to translate in vitro concentration-response curves for AChE inhibition obtained in the current study to predicted in vivo dose-response curves. The predicted dose-response curves for rat matched available in vivo data on AChE inhibition, and the benchmark dose lower confidence limits for 10% inhibition (BMDL10 values) were in line with the reported BMDL10 values. Humans were predicted to be 6-fold more sensitive than rats in terms of AChE inhibition, mainly because of inter-species differences in toxicokinetics. It is concluded that the TEF-coded DZN PBK model combined with quantitative in vitro to in vivo extrapolation (QIVIVE) provides an adequate approach to predict RBC AChE inhibition upon acute oral DZN exposure, and can provide an alternative testing strategy for derivation of a point of departure (POD) in risk assessment.
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Affiliation(s)
- Shensheng Zhao
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Sebastiaan Wesseling
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Bert Spenkelink
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University and Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
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Nidheesh T, Salim C, Rajini PS, Suresh PV. Antioxidant and neuroprotective potential of chitooligomers in Caenorhabditis elegans exposed to Monocrotophos. Carbohydr Polym 2015; 135:138-44. [PMID: 26453861 DOI: 10.1016/j.carbpol.2015.08.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/11/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022]
Abstract
The objectives of this investigation were to establish the propensity of the chitooligomers (COS) to ameliorate neurodegeneration and oxidative stress in Caenorhabditis elegans induced by an organophosphorus insecticide, Monocrotophos (MCP). COS was prepared from α-chitosan by the enzymatic method using chitosanase and characterized by HPLC and electron spray ionization-TOF-(ESI-TOF)-MS. We exposed age synchronized L4 C. elegans worms (both wild type N2 and transgenic strain BZ555 (Pdat-1:GFP) to sublethal concentration of MCP (0.75mM) for 24h in the presence or absence of COS (0.2mM). The neuroprotective effect of COS was examined in N2 worms in terms of brood size, lifespan, egg laying, dopamine content, acetylcholinesterase and carboxylesterase activity and by direct visualization and quantification of degeneration of dopaminergic neurons in BZ555. Exposure to COS extended lifespan, normalized egg laying, increased brood size, decreased the dopaminergic neurodegeneration, increased the dopamine content and increased AChE and carboxylesterase activity in C. elegans treated with MCP. COS induced a significant decrease in reactive oxygen species and increased the reduced glutathione level as well as increased superoxide dismutase and catalase activity. Our findings demonstrate that COS significantly inhibits the dopaminergic neurodegeneration and associated physiological alterations induced by MCP in C. elegans by attenuating the oxidative stress as well.
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Affiliation(s)
- T Nidheesh
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Department of Meat and Marine Sciences, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - Chinnu Salim
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Food Protectants and Infestation Control Department, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - P S Rajini
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Food Protectants and Infestation Control Department, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India
| | - P V Suresh
- Academy of Scientific and Innovative Research, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India; Department of Meat and Marine Sciences, CSIR - Central Food Technological Research Institute, Mysuru 570 020, India.
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Chiapella G, Genti-Raimondi S, Magnarelli G. Placental oxidative status in rural residents environmentally exposed to organophosphates. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 38:220-229. [PMID: 24959959 DOI: 10.1016/j.etap.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
The impact of environmental organophosphate pesticide exposure on the placenta oxidative status was assessed. Placental samples were collected from women residing in an agricultural area during pesticide pulverization period, non-pulverization period and from control group. Carboxylesterase activity was significantly decreased in pulverization period group. Enzymatic and non-enzymatic defense system, the oxidative stress biomarkers and the nuclear factor erythroid 2-related factor levels showed no differences among groups. However, in the pulverization period group, an inverse association between catalase activity and placental index, a useful metric for estimating placental inefficiency, was found. This result suggests that catalase may serve as a potential placental biomarker of susceptibility to pesticides. Further studies designed from a gene-environment perspective are needed.
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Affiliation(s)
- Graciela Chiapella
- Facultad de Ciencias Médicas, Universidad Nacional del Comahue, Cipolletti, Río Negro, Argentina; LIBIQUIMA, Instituto Multidisciplinario de Investigación y Desarrollo de la Patagonia Norte (IDEPA), CONICET - Universidad Nacional del Comahue, Neuquén, Argentina.
| | - Susana Genti-Raimondi
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
| | - Gladis Magnarelli
- Facultad de Ciencias Médicas, Universidad Nacional del Comahue, Cipolletti, Río Negro, Argentina; LIBIQUIMA, Instituto Multidisciplinario de Investigación y Desarrollo de la Patagonia Norte (IDEPA), CONICET - Universidad Nacional del Comahue, Neuquén, Argentina.
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A Method for Fast Assessment of OP/CB Exposure in the Japanese Quail (Coturnix coturnix japonica) Using Combined Esterases Enzyme Activity as Biomarkers. Enzyme Res 2014; 2014:812302. [PMID: 24527206 PMCID: PMC3913017 DOI: 10.1155/2014/812302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/09/2013] [Accepted: 11/09/2013] [Indexed: 11/17/2022] Open
Abstract
The aims of this study were to investigate the presence of different esterase activities in plasma and liver for Japanese quail and to combine determination of both carboxylesterase and cholinesterase as biochemical biomarker in order to identify the effects of carbamate and organophosphate compounds exposure. Carboxylesterase exhibits larger sensitivity to carbamate and organophosphate compounds than to cholinesterase and is present at higher levels. This permitted nature and distribution of carboxylesterase or cholinesterase to be measured. One predominant toxicological form of enzyme level constant in its patterns of motivation and inhibition with cholinesterase was identified in plasma with an apparent Michaelis constant for butyrylthiocholine iodide of 0.394 mM. Carboxylesterase activity in liver was considered by its preferential hydrolysis of the S-phenyl thioacetate. A concentration dependent decrease of carboxylesterase and cholinesterase has demonstrated during in vitro incubation of malathion, parathion, and trichlorfon in the range 0.125–2 mM, while with methomyl was in the range 0.25–4 mM. When quail (n = 15) was exposed orally for 48 h to concentrations of carbamate or organophosphate compounds of 3–200 mg/kg, the percentage inhibition of cholinesterase was in each case larger than that of carboxylesterase and reached statistical significance (P < 0.05) at lower concentrations.
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Koenig S, Guillén K, Solé M. Comparative xenobiotic metabolism capacities and pesticide sensitivity in adults of Solea solea and Solea senegalensis. Comp Biochem Physiol C Toxicol Pharmacol 2013; 157:329-36. [PMID: 23474500 DOI: 10.1016/j.cbpc.2013.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/28/2013] [Accepted: 03/03/2013] [Indexed: 01/12/2023]
Abstract
The measurement of enzymatic activities involved in xenobiotic biotransformation was carried out in adults of Solea solea and Solea senegalensis. The hepatic enzymes analysed were cytochrome P450 (CYP) related activities using eight fluorometric substrates and carboxylesterases (CbE). The conjugating activities of glutathione S-transferase (GST) and UPD-glucuronosyltransferase (UDPGT) were also assessed. Specific mammalian inhibitors were used as diagnostic tools for related activities of CYP1A (α-naphthoflavone; αNF), CYP2B6 and CYP2C19 (ticlopidine) and CYP3A4 (ketoconazole). The in vitro sensitivity to organophosphorous pesticides (OP) was tested in the S10 homogenate of brain (acetylcholinesterase-AChE) and liver (CbE). Furthermore, the pesticide chlorpyrifos oxon (CLPO) was used to explore the OP sensitivity of CbE of both species in two subcellular fractions (microsomes and cytosol), using two substrates. Overall, only two parameters confirmed species differences: EROD and cytosolic CbE being significantly elevated (p < 0.05) in the common sole, S. solea. A high inhibition of CYP1A related activities using several fluorometric substrates (ER, MR and CEC) after in vitro incubation with αNF confirmed all measure CYP1A1-related activities whereas ketoconazole was more specific for BFCOD (CYP3A4). Pesticide sensitivity was similar for brain AChE but hepatic CbE had a protective role that was species and pesticide dependent.
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Affiliation(s)
- Samuel Koenig
- Institute of Marine Sciences (ICM-CSIC), Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain
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