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Silva M, Kwok RKH. Use of computational toxicology models to predict toxicological points of departure: A case study with triazine herbicides. Birth Defects Res 2023; 115:525-544. [PMID: 36584090 DOI: 10.1002/bdr2.2144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022]
Abstract
BACKGROUND Atrazine simazine and propazine, widely used triazine herbicides on food crops and in residential areas, disrupt the neuroendocrine system raising human health concerns. USEPA developed a PBPK model based on triazine common Mode of Action (MOA)-suppression of luteinizing hormone surge in female rats-to generate human regulatory points of departure (POD: mg/kg/day). We compared triazine Human Administered Equivalent Dose (AEDHuman mg/kg/day) predictions from open access computational tools to the PBPK PODs to assess concordance. METHODS Computational tools were the following: ToxCast/Tox21 in vitro assays; Toxicogenomic databases to assess concordance with ToxCast/Tox21 targets; integrated chemical environment (ICE) models with ToxCast/Tox21 inputs to predict AEDHuman PODs and population-based age-refined high throughput toxicokinetics (HTTK-Pop) to compare to age-related PBPK PODs. RESULTS ToxCast/Tox21 assays identified critical targets in the triazine common MOA and gene databases; ICE AEDHuman predictions were mainly concordant with the USEPA PBPK PODs quantitatively. Low fold-differences between PBPK POD and ICE AEDHuman predictions indicated that the ICE models are health-protective. HTTK-Pop age-refinements were within 10-fold of the USEPA PBPK PODs. CONCLUSIONS CompTox tools were used to identify assay targets in the MOA and identify potential molecular initiating targets in the adverse outcome pathway for potential use in risk assessment.
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Affiliation(s)
- Marilyn Silva
- Retired from the California Environmental Protection Agency, Sacramento, California, USA
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Nuchan P, Kovitvadhi U, Sangsawang A, Kovitvadhi S, Klaimala P, Srakaew N. Biochemical and cellular responses of the freshwater mussel, Hyriopsis bialata, to the herbicide atrazine. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119710. [PMID: 35798193 DOI: 10.1016/j.envpol.2022.119710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/12/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
The present study aimed to evaluate biochemical and cellular responses of the freshwater mussel, Hyriopsis bialata, to the herbicide atrazine (ATZ). The mussels were exposed to environmentally-relevant concentrations of ATZ (0, 0.02 and 0.2 mg/L) and a high concentration (2 mg/L) for 0, 7, 14, 21 and 28 days. Tissues comprising male and female gonads, digestive glands and gills were collected and assessed for ethoxyresorufin-O-deethylase (EROD) activity, glutathione S-transferase (GST) activity, multixenobiotic resistance mechanism (MXR), histopathological responses, DNA fragmentation and bioaccumulation of ATZ and its transformation derivatives, desethylatrazine (DEA) and desisopropylatrazine (DIA). Additionally, circulating estradiol levels were determined. It appeared that ATZ did not cause significant changes in activities of EROD, GST and MXR. There were no apparent ATZ-mediated histopathological effects in the tissues, with the exception of the male gonads exhibiting aberrant aggregation of germ cells in the ATZ-treated mussels. Contrarily, ATZ caused significant DNA fragmentation in all tissues of the treated animals in dose- and time-dependent manners. In general, the circulating estradiol levels were higher in the females than in the males. However, ATZ-treated animals did not show significant alterations in the hormonal levels, as compared with those of the untreated animals. Herein, we showed for the first time differentially spatiotemporal distribution patterns of bioaccumulation of ATZ, DEA and DIA, with ATZ and DEA detectable in the gonads of both sexes, DEA and DIA in the digestive glands and only DEA in the gills. The differential distribution patterns of bioaccumulation of ATZ and its derivatives among the tissues point to different pathways and tissue capacity in transforming ATZ into its transformation products. Taken together, the freshwater mussel H. bialata was resistant to ATZ likely due to their effective detoxification. However, using DNA damage as a potential biomarker, H. bialata is a promising candidate for biomonitoring aquatic toxicity.
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Affiliation(s)
- Pattanan Nuchan
- Department of Zoology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Uthaiwan Kovitvadhi
- Department of Zoology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Akkarasiri Sangsawang
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Satit Kovitvadhi
- Department of Agriculture, Faculty of Science and Technology, Bansomdejchaopraya Rajabhat University, Thonburi, Bangkok, 10600, Thailand
| | - Pakasinee Klaimala
- Impact of Pesticide Use Subdivision, Pesticide Research Group, Agricultural Production Science Research and Development Office, Department of Agriculture, Ministry of Agriculture and Cooperatives, Chatuchak, Bangkok, 10900, Thailand
| | - Nopparat Srakaew
- Department of Zoology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
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Abass K, Pelkonen O, Rautio A. Chloro-s-triazines-toxicokinetic, Toxicodynamic, Human Exposure, and Regulatory Considerations. Curr Drug Metab 2021; 22:645-656. [PMID: 34218777 PMCID: PMC8811613 DOI: 10.2174/1389200222666210701164945] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/14/2021] [Accepted: 02/09/2021] [Indexed: 11/22/2022]
Abstract
Chloro-s-triazines-atrazine, cyanazine, propazine, simazine, and terbuthylazine-are structurally similar herbicides, differing only in specific s-triazine4-and 6-N alkyl substituents. It is generally regarded that their toxicokinetics, such as, metabolic pathways, biological effects and toxicities, also share more similar features than the differences. Consequently, it is useful to compare their characteristics to potentially find useful structure-activity relationships or other similarities or differences regarding different active compounds, their metabolites, and biological effects including toxic outcomes. The ultimate goal of these exercises is to apply the summarized knowledge-as far as it is possible regarding a patchy and often inadequate database-to cross the in vitro-in vivo and animal-human borders and integrate the available data to enhance toxicological risk assessment for the benefit of humans and ecosystems.
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Affiliation(s)
- Khaled Abass
- Address correspondence to this author at the Faculty of Medicine, Arctic Health, University of Oulu, FI-90014 Oulu, Finland; E-mails: ,
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Fang Y, Ni C, Dong Y, Li H, Wu S, Li X, Lv Y, Huang T, Lian Q, Ge RS. In utero Exposure to Atrazine Disrupts Rat Fetal Testis Development. Front Pharmacol 2018; 9:1391. [PMID: 30555326 PMCID: PMC6280720 DOI: 10.3389/fphar.2018.01391] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/12/2018] [Indexed: 12/20/2022] Open
Abstract
Atrazine (ATR) is a commonly used agricultural herbicide and a potential endocrine disruptor that may cause testicular dysgenesis. The objective of the present study was to investigate the effects of atrazine on fetal testis development after in utero exposure. Female Sprague-Dawley rats were gavaged daily with vehicle (corn oil, control) or atrazine (25, 50, and 100 mg/kg body weight/day) from gestational day 12 to 21. Atrazine dose-dependently decreased serum testosterone levels of male pups, with a significant difference from the control recorded at a dose of 100 mg/kg. In addition, atrazine significantly increased fetal Leydig cell aggregation at a dose of 100 mg/kg. Atrazine increased fetal Leydig cell number but not Sertoli cell number. However, atrazine down-regulated Scarb1 and Cyp17a1 in the fetal Leydig cell per se and Hsd17b3 and Dhh in the Sertoli cell per se. These results demonstrated that in utero exposure to atrazine disrupted rat fetal testis development.
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Affiliation(s)
- Yinghui Fang
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Chaobo Ni
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Yaoyao Dong
- Department of Pharmacy, The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Huitao Li
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Siwen Wu
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Xiaoheng Li
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Yao Lv
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Tongliang Huang
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Qingquan Lian
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
| | - Ren-Shan Ge
- Department of Anesthesiology, Perioperative and Pain Medicine, Key Laboratory of Anesthesiology of Zhejiang Province, Zhejiang, China
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Zimmerman AD, Breckenridge CB, Yi KD, Sawhney Coder P, Wanders D, Judd RL, Foradori CD. Changes in hepatic phase I and phase II biotransformation enzyme expression and glutathione levels following atrazine exposure in female rats. Xenobiotica 2017; 48:867-881. [PMID: 28882082 DOI: 10.1080/00498254.2017.1374486] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
1. To determine the effects of repeated atrazine (ATR) treatment on hepatic phase I and II enzymes, adult female rats were treated with vehicle or 100 mg/kg of ATR for 1, 2, 3 or 4 days. Glutathione-s-transferases (GST) mRNA expression, protein levels (mu, pi, alpha, omega), and activity (cytosolic and microsomal), along with bioavailable glutathione (GSH) were assayed. 2. GST expression, concentrations and activity were increased, along with GSH levels, in animals treated with ATR for 3 and 4 days. 3. A subsequent study was performed with animals treated with vehicle, 6.5, 50 or 100 mg/kg/day for 4, 8 or 14 days. Expression of hepatic phase I CYP 450 enzymes was evaluated in conjugation with GST expression, protein and activity. Nineteen of the 45 CYP enzymes assayed displayed increased mRNA levels after eight days of treatment in animals treated with 50 or 100 mg/kg/day. After 14 days of treatment, all CYP expression levels returned to control levels except for CYP2B2, CYP2B3, CYP2C7, CYP2C23, CYP2E1, CYP3A9, CYP4A3 and CYP27A1, which remained elevated. 4. Results indicate that there may be a habituation or adaptation of liver phase I and phase II expression following repeated ATR treatment.
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Affiliation(s)
- Arthur D Zimmerman
- a Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, AL , USA
| | | | - Kun D Yi
- b Syngenta Crop Protection LLC , Greensboro, NC , USA
| | | | - Desiree Wanders
- d Department of Nutrition, Georgia State University , Atlanta, GA , USA
| | - Robert L Judd
- a Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, AL , USA
| | - Chad D Foradori
- a Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, AL , USA
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Rong Tan L, Chen Lu Y, Jing Zhang J, Luo F, Yang H. A collection of cytochrome P450 monooxygenase genes involved in modification and detoxification of herbicide atrazine in rice (Oryza sativa) plants. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 119:25-34. [PMID: 25968601 DOI: 10.1016/j.ecoenv.2015.04.035] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/25/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Plant cytochrome P450 monooxygenases constitute one of the largest families of protein genes involved in plant growth, development and acclimation to biotic and abiotic stresses. However, whether these genes respond to organic toxic compounds and their biological functions for detoxifying toxic compounds such as herbicides in rice are poorly understood. The present study identified 201 genes encoding cytochrome P450s from an atrazine-exposed rice transcriptome through high-throughput sequencing. Of these, 69 cytochrome P450 genes were validated by microarray and some of them were confirmed by real time PCR. Activities of NADPH-cytochrome P450 reductase (CPR) and p-nitroanisole O-demethylase (PNOD) related to toxicity were determined and significantly induced by atrazine exposure. To dissect the mechanism underlying atrazine modification and detoxification by P450, metabolites (or derivatives) of atrazine in plants were analyzed by ultra performance liquid chromatography mass spectrometry (UPLC/MS). Major metabolites comprised desmethylatrazine (DMA), desethylatrazine (DEA), desisopropylatrazine (DIA), hydroxyatrazine (HA), hydroxyethylatrazine (HEA) and hydroxyisopropylatrazine (HIA). All of them were chemically modified by P450s. Furthermore, two specific inhibitors of piperonyl butoxide (PBO) and malathion (MAL) were used to assess the correlation between the P450s activity and rice responses including accumulation of atrazine in tissues, shoot and root growth and detoxification.
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Affiliation(s)
- Li Rong Tan
- Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Yi Chen Lu
- Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Jing Jing Zhang
- Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Fang Luo
- Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Hong Yang
- Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China.
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Mottier A, Séguin A, Devos A, Pabic CL, Voiseux C, Lebel JM, Serpentini A, Fievet B, Costil K. Effects of subchronic exposure to glyphosate in juvenile oysters (Crassostrea gigas): From molecular to individual levels. MARINE POLLUTION BULLETIN 2015; 95:665-77. [PMID: 25455786 DOI: 10.1016/j.marpolbul.2014.10.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/25/2014] [Accepted: 10/15/2014] [Indexed: 06/04/2023]
Abstract
Glyphosate-based herbicides are extensively used and can be measured in aquatic ecosystems, including coastal waters. The effect of glyphosate on non-target organisms is an issue of worldwide concern. The aim of this study was to investigate the effects of subchronic exposure to glyphosate in juvenile oysters, Crassostrea gigas. Yearling oysters were exposed to three concentrations of glyphosate (0.1, 1 and 100μgL(-1)) for 56days. Various endpoints were studied, from the individual level (e.g., gametogenesis and tissue alterations) to the molecular level (mRNA quantification), including biochemical endpoints such as glutathione-S-transferase (GST) and catalase activities and malondialdehyde content. No mortality and growth occurred during the experiment, and individual biomarkers revealed only slight effects. The levels of gene expression significantly increased in oysters exposed to the highest glyphosate concentration (GST and metallothioneins) or to all concentrations (multi-xenobiotic resistance). These results suggested an activation of defence mechanisms at the molecular level.
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Affiliation(s)
- Antoine Mottier
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France
| | - Alexis Séguin
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France
| | - Alexandre Devos
- Radioecology Laboratory of Cherbourg-Octeville, Institute of Radioprotection and Nuclear Safety/PRP-ENV/SERIS, BP n°10, rue Max Pol Fouchet, 50130 Octeville, France
| | - Charles Le Pabic
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France
| | - Claire Voiseux
- Radioecology Laboratory of Cherbourg-Octeville, Institute of Radioprotection and Nuclear Safety/PRP-ENV/SERIS, BP n°10, rue Max Pol Fouchet, 50130 Octeville, France
| | - Jean Marc Lebel
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France
| | - Antoine Serpentini
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France
| | - Bruno Fievet
- Radioecology Laboratory of Cherbourg-Octeville, Institute of Radioprotection and Nuclear Safety/PRP-ENV/SERIS, BP n°10, rue Max Pol Fouchet, 50130 Octeville, France
| | - Katherine Costil
- Normandie Université, Université de Caen Basse-Normandie, F-14032 Caen, France; UMR BOREA (Biologie des Organismes et des Ecosystèmes Aquatiques), MNHN, UPMC, UCBN, CNRS-7208, IRD-207, IBFA, Université de Caen Basse-Normandie, Esplanade de la Paix, CS 14032, 14032 Caen Cedex 5, France.
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Meyer AH, Dybala-Defratyka A, Alaimo PJ, Geronimo I, Sanchez AD, Cramer CJ, Elsner M. Cytochrome P450-catalyzed dealkylation of atrazine by Rhodococcus sp. strain NI86/21 involves hydrogen atom transfer rather than single electron transfer. Dalton Trans 2015; 43:12175-86. [PMID: 24851834 DOI: 10.1039/c4dt00891j] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cytochrome P450 enzymes are responsible for a multitude of natural transformation reactions. For oxidative N-dealkylation, single electron (SET) and hydrogen atom abstraction (HAT) have been debated as underlying mechanisms. Combined evidence from (i) product distribution and (ii) isotope effects indicate that HAT, rather than SET, initiates N-dealkylation of atrazine to desethyl- and desisopropylatrazine by the microorganism Rhodococcus sp. strain NI86/21. (i) Product analysis revealed a non-selective oxidation at both the αC and βC-atom of the alkyl chain, which is expected for a radical reaction, but not SET. (ii) Normal (13)C and (15)N as well as pronounced (2)H isotope effects (εcarbon: -4.0‰ ± 0.2‰; εnitrogen: -1.4‰ ± 0.3‰, KIEH: 3.6 ± 0.8) agree qualitatively with calculated values for HAT, whereas inverse (13)C and (15)N isotope effects are predicted for SET. Analogous results are observed with the Fe(iv)[double bond, length as m-dash]O model system [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin-iron(iii)-chloride + NaIO4], but not with permanganate. These results emphasize the relevance of the HAT mechanism for N-dealkylation by P450.
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Affiliation(s)
- Armin H Meyer
- Institute of Groundwater Ecology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
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Foradori CD, Sawhney Coder P, Tisdel M, Yi KD, Simpkins JW, Handa RJ, Breckenridge CB. The effect of atrazine administered by gavage or in diet on the LH surge and reproductive performance in intact female Sprague-Dawley and Long Evans rats. ACTA ACUST UNITED AC 2014; 101:262-75. [PMID: 24831581 PMCID: PMC4227606 DOI: 10.1002/bdrb.21109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 03/17/2014] [Indexed: 11/24/2022]
Abstract
Atrazine (ATR) blunts the hormone-induced luteinizing hormone (LH) surge, when administered by gavage (50–100 mg/kg/day for 4 days), in ovariectomized rats. In this study, we determined if comparable doses delivered either by gavage (bolus dose) or distributed in diet would reduce the LH surge and subsequently affect fertility in the intact female rat. ATR was administered daily to intact female Sprague-Dawley (SD) or Long Evans (LE) rats by gavage (0, 0.75 1.5, 3, 6, 10, 12, 50, or 100 mg/kg/day) or diet (0, 30, 100, 160, 500, 660, or 1460 ppm) during one complete 4-day estrous cycle, starting on day of estrus. Estrous status, corpora lutea, ova, and LH plasma concentrations were evaluated. A second cohort of animals was mated on the fourth treatment day. Fertility metrics were assessed on gestational day 20. A higher portion of LE rats had asynchronous estrous cycles when compared to SD rats both during pretreatment and in response to ATR (≥50 mg/kg). In contrast, bolus doses of ATR (≥50 mg/kg) inhibited the peak and area under the curve for the preovulatory LH surge in SD but not LE animals. Likewise, only bolus-treated SD, not LE, rats displayed reduced mean number of corpora lutea and ova. There were no effects of ATR administered by gavage on mating, gravid number, or fetus number. Dietary administration had no effect on any reproductive parameter measured. These findings indicate that short duration, high-bolus doses of ATR can inhibit the LH surge and reduce the number of follicles ovulated; however, dietary administration has no effect on any endocrine or reproductive outcomes
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Affiliation(s)
- Chad D Foradori
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
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Lin Z, Fisher JW, Wang R, Ross MK, Filipov NM. Estimation of placental and lactational transfer and tissue distribution of atrazine and its main metabolites in rodent dams, fetuses, and neonates with physiologically based pharmacokinetic modeling. Toxicol Appl Pharmacol 2013; 273:140-58. [DOI: 10.1016/j.taap.2013.08.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/07/2013] [Accepted: 08/10/2013] [Indexed: 11/27/2022]
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Abstract
Triazine herbicides are very common and only 0.1 % reach the target pests, while the rest moves into other environmental compartments. Their fate in the environment depends on their movement through the air, water, and soil and on the rate of their degradation or transformation. Triazine compounds may be transformed by water, microorganisms, and sunlight. Widespread use and persistence of triazine herbicides in soil has resulted in contamination of surface, drinking, and even rain water with parent compounds and degradation products, posing a risk to the general population.The metabolism and effects of triazine herbicides have been studied in experimental animals and in experiments in vitro. There are only a few studies of their metabolism and excretion in humans. Agricultural and manufacturing workers are exposed to triazines during application and production. Human exposure is monitored by determining parent compounds and their metabolites in urine. Due to the low concentrations of urinary metabolites in occupationally exposed persons, very sensitive analytical methods are required. This paper describes the structure and properties of symmetric triazine herbicides, their metabolism, and effects in humans and animals and the levels of these compounds in the urine of occupationally exposed persons.
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A physiologically based pharmacokinetic model for atrazine and its main metabolites in the adult male C57BL/6 mouse. Toxicol Appl Pharmacol 2010; 251:16-31. [PMID: 21094656 DOI: 10.1016/j.taap.2010.11.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/05/2010] [Accepted: 11/11/2010] [Indexed: 12/13/2022]
Abstract
Atrazine (ATR) is a chlorotriazine herbicide that is widely used and relatively persistent in the environment. In laboratory rodents, excessive exposure to ATR is detrimental to the reproductive, immune, and nervous systems. To better understand the toxicokinetics of ATR and to fill the need for a mouse model, a physiologically based pharmacokinetic (PBPK) model for ATR and its main chlorotriazine metabolites (Cl-TRIs) desethyl atrazine (DE), desisopropyl atrazine (DIP), and didealkyl atrazine (DACT) was developed for the adult male C57BL/6 mouse. Taking advantage of all relevant and recently made available mouse-specific data, a flow-limited PBPK model was constructed. The ATR and DACT sub-models included blood, brain, liver, kidney, richly and slowly perfused tissue compartments, as well as plasma protein binding and red blood cell binding, whereas the DE and DIP sub-models were constructed as simple five-compartment models. The model adequately simulated plasma levels of ATR and Cl-TRIs and urinary dosimetry of Cl-TRIs at four single oral dose levels (250, 125, 25, and 5mg/kg). Additionally, the model adequately described the dose dependency of brain and liver ATR and DACT concentrations. Cumulative urinary DACT amounts were accurately predicted across a wide dose range, suggesting the model's potential use for extrapolation to human exposures by performing reverse dosimetry. The model was validated using previously reported data for plasma ATR and DACT in mice and rats. Overall, besides being the first mouse PBPK model for ATR and its Cl-TRIs, this model, by analogy, provides insights into tissue dosimetry for rats. The model could be used in tissue dosimetry prediction and as an aid in the exposure assessment to this widely used herbicide.
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Ahmad I, Shukla S, Kumar A, Singh BK, Patel DK, Pandey HP, Singh C. Maneb and paraquat-induced modulation of toxicant responsive genes in the rat liver: comparison with polymorphonuclear leukocytes. Chem Biol Interact 2010; 188:566-79. [PMID: 20888808 DOI: 10.1016/j.cbi.2010.09.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 09/23/2010] [Accepted: 09/23/2010] [Indexed: 12/18/2022]
Abstract
Experimental studies have shown that toxicant responsive genes, cytochrome P450s (CYPs) and glutathione S-transferases (GSTs) play a critical role in pesticide-induced toxicity. CYPs play pro-oxidant role and GSTs offer protection in maneb (MB) and paraquat (PQ)-induced brain and lung toxicities. The present study aimed to investigate the effect of repeated exposures of MB and/or PQ on lipid peroxidation (LPO), glutathione content (GSH) and toxicant responsive genes, i.e., CYP1A1, 1A2, 2E1, GSTA4-4, GSTA1-1 and GSTA3-3 in the liver and to correlate the same with polymorphonuclear leukocytes (PMNs). A significant augmentation in LPO and reduction in GSH content was observed in a time of exposure dependent manner in the liver and PMNs of MB and/or PQ treated animals. The expression and catalytic activity of CYP2E1 and GSTA4-4 were significantly increased following MB and/or PQ exposure both in the liver and PMNs. Although the expression of GSTA3-3 was increased, the expression of GSTA1-1 was unaltered after MB and/or PQ treatment in both the liver and PMNs. MB augmented the expression and catalytic activity of CYP1A1 in the liver, however, CYP1A2 was unaffected. PQ, on the other hand, significantly increased hepatic CYP1A2 expression and catalytic activity. MB and/or PQ did not produce any significant changes in CYP1A1 and CYP1A2 in PMNs. The results of the study thus demonstrate that MB and PQ differentially regulate hepatic CYP1A1 and CYP1A2 while LPO, GSH, CYP2E1, GSTA4-4 and GSTA3-3 are modulated in the similar fashions both in the liver and PMNs.
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Affiliation(s)
- Israr Ahmad
- Indian Institute of Toxicology Research, Lucknow 226 001, India
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14
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Panuwet P, Restrepo PA, Magsumbol M, Jung KY, Montesano MA, Needham LL, Barr DB. An improved high-performance liquid chromatography–tandem mass spectrometric method to measure atrazine and its metabolites in human urine. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:957-62. [DOI: 10.1016/j.jchromb.2010.02.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 02/16/2010] [Accepted: 02/21/2010] [Indexed: 11/29/2022]
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15
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Quantification of atrazine and its metabolites in urine by on-line solid-phase extraction–high-performance liquid chromatography–tandem mass spectrometry. Anal Bioanal Chem 2008; 391:1931-9. [DOI: 10.1007/s00216-008-2102-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/20/2008] [Accepted: 03/25/2008] [Indexed: 11/26/2022]
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16
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Narimatsu S, Yonemoto R, Masuda K, Katsu T, Asanuma M, Kamata T, Katagi M, Tsuchihashi H, Kumamoto T, Ishikawa T, Naito S, Yamano S, Hanioka N. Oxidation of 5-methoxy-N,N-diisopropyltryptamine in rat liver microsomes and recombinant cytochrome P450 enzymes. Biochem Pharmacol 2008; 75:752-60. [DOI: 10.1016/j.bcp.2007.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 09/20/2007] [Accepted: 09/21/2007] [Indexed: 10/22/2022]
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17
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McMullin TS, Andersen ME, Tessari JD, Cranmer B, Hanneman WH. Estimating constants for metabolism of atrazine in freshly isolated rat hepatocytes by kinetic modeling. Toxicol In Vitro 2007; 21:492-501. [PMID: 17188835 DOI: 10.1016/j.tiv.2006.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2006] [Revised: 10/09/2006] [Accepted: 10/21/2006] [Indexed: 10/24/2022]
Abstract
This study estimated the kinetic constants for oxidative metabolism of atrazine (ATRA) and its chlorotriazine (Cl-TRI) metabolites, 2-chloro-4-ethylamino-6-amino-1,3,5-triazine (ETHYL), 2-chloro-4-amino-6-isopropylamino-1,3,5-triazine (ISO), and diaminochlorotriazine (DACT), using freshly isolated rat hepatocytes. Hepatocytes were incubated with 1.74, 44, 98, and 266 microM ATRA. Disappearance of ATRA and formation of the Cl-TRI metabolites were quantified over 90 min. At all incubation concentrations, ATRA was preferentially metabolized to ETHYL, producing ETHYL concentrations approximately 6 times higher than those of ISO. DACT concentrations peaked at 44 microM ATRA and decreased with increasing incubation concentrations, indicating non-linear metabolic behavior of ATRA with respect to DACT formation. A series of kinetic models were developed from these data to describe the dose and time-dependent oxidative metabolism of ATRA and the Cl-TRI metabolites. An integrated model for all the chloro-triazines included multi-substrate competitive inhibition of metabolism to describe the non-linear behavior of DACT production in relation to ATRA while simultaneously simulating the time-course behavior of the Cl-TRIs at all four ATRA concentrations. The maximal metabolic rate (V(max)) of ATRA metabolism and the Michaelis-Menten constant (K(M)) for the reaction were 1.6 microM/min and 30 microM, respectively. V(max) and K(M) values for ETHYL and ISO metabolism to DACT were also estimated using this modeling approach.
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Affiliation(s)
- Tami S McMullin
- Department of Environmental and Radiological Health Sciences, Campus Delivery, 132 Physiology Building, 1680, Colorado State University, Fort Collins, CO 80523, United States
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18
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Gotardo MCAF, Moraes LABD, Assis MD. Metalloporphyrins as biomimetic models for cytochrome p-450 in the oxidation of atrazine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:10011-8. [PMID: 17177535 DOI: 10.1021/jf062462n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The aim of this work was to evaluate whether metalloporphyrin models could mimic the action of cytochrome P-450 in the oxidation of atrazine, a herbicide. The commercially available second-generation metalloporphyrins 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin metal(III) chloride [M(TDCPP)Cl] and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin metal(III) chloride [M(TFPP)Cl] (metal = Fe or Mn) and the oxidants iodosylbenzene and metachloroperbenzoic acid were employed in this study. Results showed that the metalloporphyrins used here can oxidize atrazine. Yields as high as 32% were obtained for the Mn(TFPP)Cl/PhIO system, which shows that these catalysts can mimic both the in vivo and the in vitro action of cytochrome P-450, with formation of the metabolites DEA and DIA. The formation of five other unknown products was also detected, but only one of them could be identified, since the other four were present in very low concentrations. The compound COA, identified by mass spectrometry, was the main product in most of the oxidation reactions.
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Affiliation(s)
- Maria C A F Gotardo
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil
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19
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Li A, May MP, Bigelow JC. Identification of a metabolite of atrazine, N-ethyl-6-methoxy-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine, upon incubation with rat liver microsomes. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 836:129-32. [PMID: 16600698 DOI: 10.1016/j.jchromb.2006.03.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Revised: 03/14/2006] [Accepted: 03/15/2006] [Indexed: 10/24/2022]
Abstract
Atrazine is an herbicide which has shown potential antimalarial effects both in vitro and in vivo in rats. In order to study the metabolism of atrazine in rat livers, we developed a sensitive LC/MS/MS method for the identification of atrazine and several of its metabolites. Using this method, we identified one previously unreported metabolite with a mass of 211 Da in addition to two known metabolites. This new metabolite was confirmed to be N-ethyl-6-methoxy-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine, also known as atraton, by comparison of the LC/MS/MS mass spectra and the retention time to those of a commercial standard.
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Affiliation(s)
- Aiqun Li
- Department of Pharmaceutical Sciences, College of Pharmacy, Idaho State University, Pocatello, ID 83209-8334, USA
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20
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Patel S, Singh V, Kumar A, Gupta YK, Singh MP. Status of antioxidant defense system and expression of toxicant responsive genes in striatum of maneb- and paraquat-induced Parkinson's disease phenotype in mouse: Mechanism of neurodegeneration. Brain Res 2006; 1081:9-18. [PMID: 16510128 DOI: 10.1016/j.brainres.2006.01.060] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 01/16/2006] [Accepted: 01/17/2006] [Indexed: 11/19/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder contributed by the combination of age, genetic and environmental factors. Several studies have clearly shown increase in the incidences of PD in the rural environments and hypothesized the involvement of pesticides such as paraquat and maneb in neurodegeneration. These studies have prompted researchers to develop paraquat and maneb models to study the effect of co-treatment of maneb and paraquat on neuronal toxicity; however, the mechanism underlying maneb and paraquat co-treatment induced neuronal toxicity has not yet been clearly understood. The involvement of cytochrome P4502E1 and glutathione S-transferases A4-4 enzymes in the detoxification of several pesticides such as atrazine, fenamirol, organophosphorous insecticide parathion, methoxychlor, diethyl dithiocarbamate and paraquat has been known. The contribution of CYP2E1 and GSTA4-4 in neuronal toxicity has also been reported. The present study was therefore undertaken to investigate the mechanism of maneb- and paraquat-induced neurodegeneration by estimating the level of antioxidant defense enzymes in the striatum and measuring the differential expressions of CYP2E1 and GSTA4-4 genes. Animals were treated with and without maneb (30 mg/kg, i.p.) or paraquat (10 mg/kg, i.p.) either alone or in combination in exposure time-dependent manner. A significant increase in catalase, glutathione S-transferase and lipid peroxidation in the striatum was found following 3, 6 and 9 weeks of co-treatment as compared with individual treatment or controls. Individual treatment of maneb or paraquat did not exhibit any significant alteration in CYP2E1 and GSTA4-4 expression up to 6 weeks; however, an augmentation in CYP2E1 and GSTA4-4 expression was observed in the animals exposed to maneb or paraquat for 9 weeks. Augmentation in the expression of CYP2E1 and GSTA4-4 was more pronounced in the animals treated with maneb and paraquat in combination for nine weeks. A significant reduction in the augmented lipid peroxidation in the striatum was observed when the striatum was pre-administered with CYP2E1 inhibitors; however, glutathione pre-administration induced lipid peroxidation. Results obtained from the present investigation suggest the involvement of CYP2E1 and GSTA4-4 in the augmentation of the lipid peroxidation thereby enhancing neurodegeneration.
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Affiliation(s)
- Suman Patel
- Industrial Toxicology Research Centre (ITRC), Mahatma Gandhi Marg, Post Box- 80, Lucknow- 226 001, UP, India
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21
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Chowdhury P, MacLeod S, Udupa KB, Rayford PL. Pathophysiological effects of nicotine on the pancreas: an update. Exp Biol Med (Maywood) 2002; 227:445-54. [PMID: 12094008 DOI: 10.1177/153537020222700708] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Epidemiological evidence strongly suggests an association between cigarette smoking and pancreatic diseases. It is well recognized that nicotine, a major component in cigarette smoke, is an addictive agent and, therefore, reinforces smoking behavior. The current review update focuses on the genetics of nicotine dependence and its role on the development of pancreatic diseases. The role of smoking and nicotine in pancreatitis and pancreatic cancer development is also discussed. Exposure of laboratory animals to nicotine clearly supports the notion that nicotine can induce pancreatic injury. The mechanism by which nicotine induces such effects is perhaps mediated via signal transduction pathways in the pancreatic acinar cell, leading to enhanced levels of intracellular calcium release, resulting in cytotoxicity and eventual cell death. The induction of pancreatic injury by nicotine may also involve activation and expression of protooncogene, H-ras, which can increase cytosolic calcium via second messenger pathways. Development of pancreatic carcinoma in cigarette smokers as observed in human populations may be the result of activation and mutation of the H-ras gene. A possible pathogenetic mechanism of nicotine in the pancreas activating multiple signal transduction pathways is schematically summarized in Figure 1.
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Affiliation(s)
- Parimal Chowdhury
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA.
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22
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Oyama M, Ikeda T, Lim T, Ikebukuro K, Masuda Y, Karube I. Detection of toxic chemicals with high sensitivity by measuring the quantity of induced P450 mRNAs based on surface plasmon resonance. Biotechnol Bioeng 2001; 71:217-22. [PMID: 11291031 DOI: 10.1002/1097-0290(2000)71:3<217::aid-bit1011>3.0.co;2-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study we describe a novel sensor system to detect toxic chemicals based on measurement of the quantity of Saccharomyces cerevisiae P450 mRNAs induced by them. Detection was conducted using a flow-injection-type sensor system based on surface plasmon resonance (SPR). The DNA and peptide nucleic acid (PNA) probes containing a complementary sequence to a part of P450 mRNA were immobilized on the sensor chip and the P450 mRNAs hybridized to the probes were quantified. We succeeded in detecting 10 ng/L (10 ppt) of atrazine using both DNA and PNA probes. Using this sensor system, we were able to detect bisphenol A in addition to atrazine. Furthermore, we achieved higher sensitivity by amplifying the target P450 mRNA based on nucleic acid sequence-based amplification (NASBA). This method allows for sensitive, rapid, and easy detection of some toxic chemicals.
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Affiliation(s)
- M Oyama
- Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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23
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Downs CA, Dillon RT, Fauth JE, Woodley CM. A molecular biomarker system for assessing the health of gastropods (Ilyanassa obsoleta) exposed to natural and anthropogenic stressors. JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 2001; 259:189-214. [PMID: 11343712 DOI: 10.1016/s0022-0981(01)00233-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We developed a Molecular Biomarker System (MBS) to assess the physiological status of mud snails (Ilyanassa obsoleta) challenged by exposure to high temperature, cadmium, atrazine, endosulfan and the water-accommodating fraction of bunker fuel #2. The MBS is used to assay specific cellular parameters of the gastropod cell that are indicative of a non-stressed or stressed condition. The MBS distinguished among responses to each stressor and to non-stressed control conditions. For example, the biomarkers metallothionein and cytochrome P450 2E1 homologue distinguished between metal and non-metal stresses. MBS data from this study corroborate toxicological studies of organismal responses to endosulfan, atrazine, fuel and cadmium stresses. The MBS technology aids in the accurate diagnosis of the snail's health condition because the physiological significance of the changes of each biomarker is well known. This technology is particularly relevant for environmental monitoring because gastropods are used as key indicator species in many estuarine, marine, freshwater and terrestrial ecosystems. Finally, the Molecular Biomarker System technology is relatively inexpensive, easy to implement, precise and can be quickly adapted to an automated, high-throughput system for large sample analysis.
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Affiliation(s)
- C A. Downs
- Marine Biotechnology Program, US National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Ft. Johnson Rd., 29412, Charleston, SC, USA
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24
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Hanioka N, Jinno H, Tanaka-Kagawa T, Nishimura T, Ando M. Interaction of bisphenol A with rat hepatic cytochrome P450 enzymes. CHEMOSPHERE 2000; 41:973-978. [PMID: 10879814 DOI: 10.1016/s0045-6535(99)00529-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of bisphenol A (BPA) on the kinetics of cytochrome P450 (P450)-dependent monooxygenases in rat liver microsomes was studied. Testosterone 16beta-hydroxylase (TS16BH) and testosterone 2alpha-hydroxylase (TS2AH) activities were extensively inhibited by BPA at 100 microM (69% and 74%, respectively). The inhibition type was mixed for both P450-dependent monooxyganases. The Ki of TS16BH and TS2AH from Lineweaver-Burk plots were 25.9 and 24.9 microM, respectively. The activities of acetanilide 4-hydroxylase (AA4H), 7-ethoxycoumarin O-deethylase (ECOD), bufuralol 1'-hydroxylase (BF1'H), chlorzoxazone 6-hydroxylase (CZ6H) and testosterone 6beta-hydroxylase (TS6BH) were also effectively inhibited by BPA at 100 microM (43-52%). The inhibition type of these P450-dependent monooxygenases was mixed or uncompetitive, and the K(i)s (50.5-88.5 microM) were higher than those of TS16BH and TS2AH. By contrast, the values of IC50 and Ki of testosterone 7alpha-hydroxylase (TS7AH) and lauric acid omega-hydroxylase (LAOH) for BPA were >1000 microM. These results suggest that BPA interacts with rat hepatic CYP1A2, CYP2A2, CYP2B2, CYP2C11, CYP2D1, CYP2E1 and CYP3A2 in vitro.
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Affiliation(s)
- N Hanioka
- Division of Environmental Chemistry, National Institute of Health Sciences, Tokyo, Japan.
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25
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Lim T, Oyama M, Ikebukuro K, Karube I. Detection of atrazine based on the SPR determination of P450 mRNA levels in Saccharomyces cerevisiae. Anal Chem 2000; 72:2856-60. [PMID: 10905318 DOI: 10.1021/ac9914465] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe a novel method for quantification of atrazine based on detection of P450 mRNA levels in Saccharomyces cerevisiae. The selected oligonucleotide probe exhibited specificity against P450 mRNA and was successfully immobilized on the sensor chip. The mRNA was subsequently quantified by RU change using a SPR system. When the cells were disrupted by boiling, mRNA could be measured without further purification at reduced sensitivity. This simple technique permits the detection of atrazine within 15 min. This rapid and highly sensitive method can be used for the detection of atrazine.
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Affiliation(s)
- T Lim
- Research Center for Advanced Science and Technology, The University of Tokyo, Japan
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26
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Hanioka N, Jinno H, Tanaka-Kagawa T, Nishimura T, Ando M. In vitro metabolism of chlorotriazines: characterization of simazine, atrazine, and propazine metabolism using liver microsomes from rats treated with various cytochrome P450 inducers. Toxicol Appl Pharmacol 1999; 156:195-205. [PMID: 10222312 DOI: 10.1006/taap.1999.8648] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The in vitro metabolism of chlorotriazines, simazine (SIZ), atrazine (ATZ), and propazine (PRZ) was studied using control, 3-methylcholanthrene-, phenobarbital-, pyridine-, dexamethasone-, and clofibrate-treated rat liver microsomes. The metabolites were determined by HPLC. The principal reactions by cytochrome P450 (P450) system were N-monodealkylation and isopropylhydroxylation in all rat liver microsomes. As a result, 2-chloro-4-ethylamino-6-amino-1,3,5-triazine (M1) (SIZ-M1 for SIZ and ATZ-M1 for ATZ) and 2-chloro-4-amino-6-isopropylamino-1,3, 5-triazine (M2) (ATZ-M2 for ATZ and PRZ-M2 for PRZ), 2-chloro-4-ethylamino-6-(1-hydroxyisopropylamino)-1,3,5-triazine (M3) (ATZ-M3 for ATZ), and 2-chloro-4-isopropylamino-6-(1-hydroxyisopropylamino)-1,3,5-triazi ne (M4) (PRZ-M4 for PRZ) were detected as the metabolites. N-bidealkylation and 2-hydroxylation were not found in this system. The formation rates of SIZ-M1, ATZ-M1, ATZ-M2, and PRZ-M2 were markedly induced by 3-methylcholanthrene, phenobarbital, and pyridine. On the other hand, the formation rates of ATZ-M3 and PRZ-M4 were significantly induced by phenobarbital, pyridine, and/or clofibrate, but not by 3-methylcholanthrene. The enzyme kinetics of chlorotriazine metabolism were examined by mean of Eadie-Hofstee analyses. Although there was no remarkable difference of Km for the products in chlorotriazine metabolism among the microsomes tested, the Vmax and Clint (Vmax/Km) for the products in chlorotriazine metabolism are affected by P450 inducers, except for dexamethasone. The formation rates of SIZ-M1, ATZ-M1, ATZ-M2, and PRZ-M2 were significantly correlated with 7-ethoxyresorufin O-deethylase, acetanilide 4-hydroxylase, 7-ethoxycoumarin O-deethylase, 4-nitrophenol 2-hydroxylase, and testosterone 7alpha-hydroxylase activities and CYP1A1/2 level, whereas the formation rates of ATZ-M3 and PRZ-M4 were significantly correlated with testosterone 16beta-hydroxylase, bufuralol 1'-hydroxylase, and 4-nitrophenol 2-hydroxylase activities and CYP2B1/2 level. These results suggest that the inducibility in metabolism of SIZ, ATZ, and PRZ is different between N-monodealkylation and isopropylhydroxylation and that the N-monodealkylation and isopropylhydroxylation are induced by CYP1A1/2, CYP2B1/2, and CYP2B1/2, respectively.
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Affiliation(s)
- N Hanioka
- Division of Environmental Chemistry, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan.
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