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Adomako-Bonsu AG, Jacobsen J, Maser E. Metabolic activation of 2,4,6-trinitrotoluene; a case for ROS-induced cell damage. Redox Biol 2024; 72:103082. [PMID: 38527399 PMCID: PMC10979124 DOI: 10.1016/j.redox.2024.103082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 03/27/2024] Open
Abstract
The explosive compound 2,4,6-trinitrotoluene (TNT) is well known as a major component of munitions. In addition to its potential carcinogenicity and mutagenicity in humans, recent reports have highlighted TNT toxicities in diverse organisms due to its occurrence in the environment. These toxic effects have been linked to the intracellular metabolism of TNT, which is generally characterised by redox cycling and the generation of noxious reactive molecules. The reactive intermediates formed, such as nitroso and hydroxylamine compounds, also interact with oxygen molecules and cellular components to cause macromolecular damage and oxidative stress. The current review aims to highlight the crucial role of TNT metabolism in mediating TNT toxicity, via increased generation of reactive oxygen species. Cellular proliferation of reactive species results in depletion of cellular antioxidant enzymes, DNA and protein adduct formation, and oxidative stress. While TNT toxicity is well known, its ability to induce oxidative stress, resulting from its reductive activation, suggests that some of its toxic effects may be caused by its reactive metabolites. Hence, further research on TNT metabolism is imperative to elucidate TNT-induced toxicities.
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Affiliation(s)
- Amma Gyapomah Adomako-Bonsu
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Jana Jacobsen
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany.
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2
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Zhou Y, Wang C, Nie Y, Wu L, Xu A. 2,4,6-trinitrotoluene causes mitochondrial toxicity in Caenorhabditis elegans by affecting electron transport. ENVIRONMENTAL RESEARCH 2024; 252:118820. [PMID: 38555093 DOI: 10.1016/j.envres.2024.118820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 04/02/2024]
Abstract
As a typical energetic compound widely used in military activities, 2,4,6-trinitrotoluene (TNT) has attracted great attention in recent years due to its heavy pollution and wide distribution in and around the training facilities, firing ranges, and demolition sites. However, the subcellular targets and the underlying toxic mechanism of TNT remain largely unknown. In this study, we explored the toxic effects of TNT biological reduction on the mitochondrial function and homeostasis in Caenorhabditis elegans (C. elegans). With short-term exposure of L4 larvae, 10-1000 ng/mL TNT reduced mitochondrial membrane potential and adenosine triphosphate (ATP) content, which was associated with decreased expression of specific mitochondrial complex involving gas-1 and mev-1 genes. Using fluorescence-labeled transgenic nematodes, we found that fluorescence expression of sod-3 (muls84) and gst-4 (dvls19) was increased, suggesting that TNT disrupted the mitochondrial antioxidant defense system. Furthermore, 10 ng/mL TNT exposure increased the expression of the autophagy-related gene pink-1 and activated mitochondrial unfolded protein response (mt UPR), which was indicated by the increased expression of mitochondrial stress activated transcription factor atfs-1, ubiquitin-like protein ubl-5, and homeobox protein dve-1. Our findings demonstrated that TNT biological reduction caused mitochondrial dysfunction and the development of mt UPR protective stress responses, and provided a basis for determining the potential risks of energetic compounds to living organisms.
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Affiliation(s)
- Yanping Zhou
- Center of Free Electron Laser & High Magnetic Field, Anhui University, Hefei, 230601, PR China
| | - Chunyan Wang
- Center of Free Electron Laser & High Magnetic Field, Anhui University, Hefei, 230601, PR China
| | - Yaguang Nie
- Center of Free Electron Laser & High Magnetic Field, Anhui University, Hefei, 230601, PR China.
| | - Lijun Wu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, PR China
| | - An Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, 230601, PR China; Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, High Magnetic Field Laboratory, HFIPS, Chinese Academy of Science, Anhui, Hefei, 230031, PR China.
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3
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Ring-shaped cataract and urinary metabolites among 2,4,6-trinitrotoluene exposed population of Pakistan. Int Ophthalmol 2022; 42:2619-2624. [DOI: 10.1007/s10792-022-02252-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 03/12/2022] [Indexed: 11/26/2022]
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Čėnas N, Nemeikaitė-Čėnienė A, Kosychova L. Single- and Two-Electron Reduction of Nitroaromatic Compounds by Flavoenzymes: Mechanisms and Implications for Cytotoxicity. Int J Mol Sci 2021; 22:ijms22168534. [PMID: 34445240 PMCID: PMC8395237 DOI: 10.3390/ijms22168534] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/30/2021] [Accepted: 08/04/2021] [Indexed: 12/14/2022] Open
Abstract
Nitroaromatic compounds (ArNO2) maintain their importance in relation to industrial processes, environmental pollution, and pharmaceutical application. The manifestation of toxicity/therapeutic action of nitroaromatics may involve their single- or two-electron reduction performed by various flavoenzymes and/or their physiological redox partners, metalloproteins. The pivotal and still incompletely resolved questions in this area are the identification and characterization of the specific enzymes that are involved in the bioreduction of ArNO2 and the establishment of their contribution to cytotoxic/therapeutic action of nitroaromatics. This review addresses the following topics: (i) the intrinsic redox properties of ArNO2, in particular, the energetics of their single- and two-electron reduction in aqueous medium; (ii) the mechanisms and structure-activity relationships of reduction in ArNO2 by flavoenzymes of different groups, dehydrogenases-electrontransferases (NADPH:cytochrome P-450 reductase, ferredoxin:NADP(H) oxidoreductase and their analogs), mammalian NAD(P)H:quinone oxidoreductase, bacterial nitroreductases, and disulfide reductases of different origin (glutathione, trypanothione, and thioredoxin reductases, lipoamide dehydrogenase), and (iii) the relationships between the enzymatic reactivity of compounds and their activity in mammalian cells, bacteria, and parasites.
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Affiliation(s)
- Narimantas Čėnas
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania;
- Correspondence: ; Tel.: +370-5-223-4392
| | - Aušra Nemeikaitė-Čėnienė
- State Research Institute Center for Innovative Medicine, Santariškių St. 5, LT-08406 Vilnius, Lithuania;
| | - Lidija Kosychova
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania;
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Gonsalves MD, McLennan L, Slitt AL, Smith JL, Oxley JC. In vitro metabolism of HMTD and blood stability and toxicity of peroxide explosives (TATP and HMTD) in canines and humans. Xenobiotica 2021; 51:394-403. [PMID: 33439760 DOI: 10.1080/00498254.2021.1874563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) are prominent explosive threats. Mitigation of peroxide explosives is a priority among the law enforcement community, with canine (K9) units being trained to recognise the scent of peroxide explosives. Herein, the metabolism, blood distribution, and toxicity of peroxide explosives are investigated.HMTD metabolism studies in liver microsomes identified two potential metabolites, tetramethylene diperoxide diamine alcohol aldehyde (TMDDAA) and tetramethylene peroxide diamine dialcohol dialdehyde (TMPDDD).Blood stability studies in dogs and humans showed that HMTD was rapidly degraded, whereas TATP remained for at least one week.Toxicity studies in dog and human hepatocytes indicated minimum cell death for both TATP and HMTD.
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Affiliation(s)
| | - Lindsay McLennan
- Department of Chemistry, University of Rhode Island, Kingston, RI, USA
| | - Angela L Slitt
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - James L Smith
- Department of Chemistry, University of Rhode Island, Kingston, RI, USA
| | - Jimmie C Oxley
- Department of Chemistry, University of Rhode Island, Kingston, RI, USA
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Koske D, Goldenstein NI, Rosenberger T, Machulik U, Hanel R, Kammann U. Dumped munitions: New insights into the metabolization of 2,4,6-trinitrotoluene in Baltic flatfish. MARINE ENVIRONMENTAL RESEARCH 2020; 160:104992. [PMID: 32907729 DOI: 10.1016/j.marenvres.2020.104992] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Livers from dab (Limanda limanda), plaice (Pleuronectes platessa) and flounder (Platichthys flesus) sampled from the Baltic Sea were used to determine the interaction of flatfish CYP1A enzymes with 2,4,6-trinitrotoluene (TNT) in vitro. Competitive inhibition of 7-ethoxyresorufin-O-deethylase (EROD) and 7-methoxyresorufin-O-deethylase (MROD) could be demonstrated for all three flatfish species. The highest inhibition of CYP1A activities was measured in liver samples of flounder resulting in a half maximal inhibitory concentration (IC50) of 28.1 μM TNT. Due to their lower inhibition (EROD IC50 65.2 μM TNT, MROD IC50 40.3 μM TNT), dab liver samples were used to conduct in vitro metabolization experiments with TNT. The metabolization of TNT in fish was investigated with post-mitochondrial fractions (PMF) of dab liver as a model system after adding different cofactors. Rapid and time-dependent enzymatic degradation of TNT was observed. The concentrations of 4-amino-2,6-dinitrotoluene and 2-amino-4,6-dinitrotoluene increased in the samples over time. Additionally, 2,2,6,6-tetranitro-4,4-azoxytoluene was detected in one sample. The results of this study indicate that in vitro experiments are useful to investigate the xenobiotic metabolism of fish under controlled conditions prior to field studies. The metabolites found can serve as target compounds for marine monitoring of TNT contamination in munition dumpsites.
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Affiliation(s)
- Daniel Koske
- Thünen-Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany.
| | - Nadine I Goldenstein
- Thünen-Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Timothy Rosenberger
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University, Carl-von-Ossietzky Straße 9-11, 26111, Oldenburg, Germany
| | - Ulrike Machulik
- Thünen-Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Reinhold Hanel
- Thünen-Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Ulrike Kammann
- Thünen-Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
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7
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Gonsalves MD, Colizza K, Smith JL, Oxley JC. In vitro and in vivo studies of triacetone triperoxide (TATP) metabolism in humans. Forensic Toxicol 2020. [DOI: 10.1007/s11419-020-00540-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Abstract
Purpose
Triacetone triperoxide (TATP) is a volatile but powerful explosive that appeals to terrorists due to its ease of synthesis from household items. For this reason, bomb squad, canine (K9) units, and scientists must work with this material to mitigate this threat. However, no information on the metabolism of TATP is available.
Methods
In vitro experiments using human liver microsomes and recombinant enzymes were performed on TATP and TATP-OH for metabolite identification and enzyme phenotyping. Enzyme kinetics for TATP hydroxylation were also investigated. Urine from laboratory personnel collected before and after working with TATP was analyzed for TATP and its metabolites.
Results
While experiments with flavin monooxygenases were inconclusive, those with recombinant cytochrome P450s (CYPs) strongly suggested that CYP2B6 was the principle enzyme responsible for TATP hydroxylation. TATP-O-glucuronide was also identified and incubations with recombinant uridine diphosphoglucuronosyltransferases (UGTs) indicated that UGT2B7 catalyzes this reaction. Michaelis–Menten kinetics were determined for TATP hydroxylation, with Km = 1.4 µM and Vmax = 8.7 nmol/min/nmol CYP2B6. TATP-O-glucuronide was present in the urine of all three volunteers after being exposed to TATP vapors showing good in vivo correlation to in vitro data. TATP and TATP-OH were not observed.
Conclusions
Since scientists working to characterize and detect TATP to prevent terrorist attacks are constantly exposed to this volatile compound, attention should be paid to its metabolism. This paper is the first to elucidate some exposure, metabolism and excretion of TATP in humans and to identify a marker of TATP exposure, TATP-O-glucuronide in urine.
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Zhou Y, Liu X, Jiang W, Shu Y, Xu G. A theoretical insight into the reaction mechanisms of a 2,4,6-trinitrotoluene nitroso metabolite with thiols for toxic effects. Toxicol Res (Camb) 2019; 8:270-276. [PMID: 30997026 DOI: 10.1039/c8tx00326b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 01/31/2019] [Indexed: 01/08/2023] Open
Abstract
2,4,6-Trinitrotoluene (TNT) is a class C carcinogen as rated by the Environmental Protection Agency. One of the toxicity mechanisms of TNT is the covalent binding of its metabolites to critical proteins. However, knowledge about their molecular reaction mechanisms is scarce. Herein, we have provided density functional theory (DFT) simulation evidences for the reaction mechanisms of the nitroso metabolite of TNT with the sulfhydryl group of model thiols for the first time. The results show that the solvent-mediated proton-transfer mechanism plays a significant role in the entire process. For the formation of semimercaptal, the mechanism is slightly different from the previous one where the thiolate anion attacks the nitroso group. The rearrangement of semimercaptal needs to be triggered by an acid or hydrated ion (H3O+), which is consistent with the previous assumption. The other pathway, the conversion of semimercaptal to hydroxylamine, has to overcome a higher barrier, although it does not need the participation of an acid or a hydrated ion. In addition, the details on transition states, intermediates and free energy surfaces for three reactions are given, which make up for the lack of experimental knowledge. These conclusions can help to deeply understand the toxic effects of TNT and other nitroaromatic explosives.
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Affiliation(s)
- Yang Zhou
- College of Chemistry and Environmental Engineering , Sichuan University of Science and Engineering , Zigong 643000 , China . .,Institute of Chemical Materials , China Academy of Engineering and Physics , 621900 Mianyang , China
| | - Xiaoqiang Liu
- College of Chemistry and Environmental Engineering , Sichuan University of Science and Engineering , Zigong 643000 , China .
| | - Weidong Jiang
- College of Chemistry and Environmental Engineering , Sichuan University of Science and Engineering , Zigong 643000 , China .
| | - Yuanjie Shu
- College of Chemistry and Environmental Engineering , Sichuan University of Science and Engineering , Zigong 643000 , China .
| | - Guojun Xu
- The 1st Affiliated Hospital of Dalian Medical University , 116000 Dalian , China .
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Appel D, Strehse JS, Martin HJ, Maser E. Bioaccumulation of 2,4,6-trinitrotoluene (TNT) and its metabolites leaking from corroded munition in transplanted blue mussels (M. edulis). MARINE POLLUTION BULLETIN 2018; 135:1072-1078. [PMID: 30301003 DOI: 10.1016/j.marpolbul.2018.08.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/07/2018] [Accepted: 08/12/2018] [Indexed: 05/27/2023]
Abstract
Bioaccumulation of 2,4,6-trinitrotoluene (TNT) and its main metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) leaking from corroded munitions at a munitions dumping site (Kolberger Heide, Germany) was evaluated in transplanted blue mussels (Mytilus edulis). Six moorings with mussel bags were placed east and west at varying positions near the mine mound. In order to monitor any differences resulting from changing seasons, three exposure times were chosen. First exposure period: April-July 2016 (106 days); second exposure period: July-December 2016 (146 days); third exposure period: December 2016-March 2017 (92 days). We found amounts of 4-ADNT in mussel tissue ranging from 2.40 ± 2.13 to 7.76 ± 1.97 ng/(g mussel wet weight). Neither TNT nor 2-ADNT could be detected. Considering seasonal differences, orientation and distances of the moorings to the mine mound no correlation between levels in mussel tissue was evident.
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Affiliation(s)
- Daniel Appel
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, Brunswiker Str. 10, 24105 Kiel, Germany.
| | - Jennifer S Strehse
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, Brunswiker Str. 10, 24105 Kiel, Germany
| | - Hans-Jörg Martin
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, Brunswiker Str. 10, 24105 Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, Brunswiker Str. 10, 24105 Kiel, Germany
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Yang Z, Chen J, Zhou Y, Huang H, Xu D, Zhang C. Understanding the hydrogen transfer mechanism for the biodegradation of 2,4,6-trinitrotoluene catalyzed by pentaerythritol tetranitrate reductase: molecular dynamics simulations. Phys Chem Chem Phys 2018; 20:12157-12165. [DOI: 10.1039/c8cp00345a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic pollutant.
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Affiliation(s)
- Zhilin Yang
- Institute of Chemical Materials
- Chinese Academy of Engineering and Physics
- 621900 Mianyang
- China
| | - Junxian Chen
- MOE Key Laboratory of Green Chemistry & Technology
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Yang Zhou
- Institute of Chemical Materials
- Chinese Academy of Engineering and Physics
- 621900 Mianyang
- China
| | - Hui Huang
- Institute of Chemical Materials
- Chinese Academy of Engineering and Physics
- 621900 Mianyang
- China
| | - Dingguo Xu
- MOE Key Laboratory of Green Chemistry & Technology
- College of Chemistry
- Sichuan University
- Chengdu
- P. R. China
| | - Chaoyang Zhang
- Institute of Chemical Materials
- Chinese Academy of Engineering and Physics
- 621900 Mianyang
- China
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Mariussen E, Stornes SM, Bøifot KO, Rosseland BO, Salbu B, Heier LS. Uptake and effects of 2, 4, 6 - trinitrotoluene (TNT) in juvenile Atlantic salmon (Salmo salar). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 194:176-184. [PMID: 29197231 DOI: 10.1016/j.aquatox.2017.11.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/17/2017] [Accepted: 11/23/2017] [Indexed: 05/27/2023]
Abstract
Organ specific uptake and depuration, and biological effects in Atlantic salmon (Salmo salar) exposed to 2, 4, 6-trinitrotoluene (TNT) were studied. Two experiments were conducted, the first using radiolabeled TNT (14C-TNT, 0.16mg/L) to study uptake (48h) and depuration (48h), while the second experiment focused on physiological effects in fish exposed to increasing concentrations of unlabeled TNT (1μg-1mg/L) for 48h. The uptake of 14C-TNT in the gills and most of the organs increased rapidly during the first 6h of exposure (12h in the brain) followed by a rapid decrease even though the fish were still exposed to TNT in the water. The radioactivity in the gall bladder reached a maximum after 55h, 7h after the transfer to the clean water. A high concentration of 14C-TNT in the gall bladder indicates that TNT is excreted through the gall bladder. Mortality (2 out of 14) was observed at a concentration of 1mg/L, and the surviving fish had hemorrhages in the dorsal muscle tissue near the spine. Analysis of the physiological parameters in blood from the high exposure group revealed severe effects, with an increase in the levels of glucose, urea and HCO3, and a decrease in hematocrit and the levels of Cl and hemoglobin. No effects on blood physiology were observed in fish exposed to the lower concentrations of TNT (1-100μg/L). TNT and the metabolites 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) were found in the muscle tissue, whereas only 2-ADNT and 4-ADNT were found in the bile. The rapid excretion and estimated bioconcentration factors (range of 2-18 after 48h in gills, blood, liver, kidney, muscle and brain) indicated a low potential for bioaccumulation of TNT.
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Affiliation(s)
- Espen Mariussen
- Norwegian Defence Research Establishment (FFI), P.O. Box 25, N-2027 Kjeller, Norway; Norwegian Institute for Air Research (NILU), P.O. Box 100, NO-2027 Kjeller, Norway.
| | - Siv Marie Stornes
- Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway
| | - Kari Oline Bøifot
- Norwegian Defence Research Establishment (FFI), P.O. Box 25, N-2027 Kjeller, Norway
| | - Bjørn Olav Rosseland
- Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway
| | - Brit Salbu
- Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway
| | - Lene Sørlie Heier
- Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway; Norwegian Public Roads Administration, Region Øst, P.O. Box 1010 Nordre Ål, 2605 Lillehammer, Norway
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Arbeli Z, Garcia-Bonilla E, Pardo C, Hidalgo K, Velásquez T, Peña L, C ER, Avila-Arias H, Molano-Gonzalez N, Brandão PFB, Roldan F. Persistence of pentolite (PETN and TNT) in soil microcosms and microbial enrichment cultures. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:9144-9155. [PMID: 26832872 DOI: 10.1007/s11356-016-6133-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Abstract
Pentolite is a mixture (1:1) of 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN), and little is known about its fate in the environment. This study was aimed to determine the dissipation of pentolite in soils under laboratory conditions. Microcosm experiments conducted with two soils demonstrated that dissipation rate of PETN was significantly slower than that of TNT. Interestingly, the dissipation of PETN was enhanced by the presence of TNT, while PETN did not enhanced the dissipation of TNT. Pentolite dissipation rate was significantly faster under biostimulation treatment (addition of carbon source) in soil from the artificial wetland, while no such stimulation was observed in soil from detonation field. In addition, the dissipation rate of TNT and PETN in soil from artificial wetland under biostimulation was significantly faster than the equivalent abiotic control, although it seems that non-biological processes might also be important for the dissipation of TNT and PETN. Transformation of PETN was also slower during establishment of enrichment culture using pentolite as the sole nitrogen source. In addition, transformation of these explosives was gradually reduced and practically stopped after the forth cultures transfer (80 days). DGGE analysis of bacterial communities from these cultures indicates that all consortia were dominated by bacteria from the order Burkholderiales and Rhodanobacter. In conclusion, our results suggest that PETN might be more persistent than TNT.
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Affiliation(s)
- Ziv Arbeli
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia.
| | - Erika Garcia-Bonilla
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Cindy Pardo
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Kelly Hidalgo
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Trigal Velásquez
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Luis Peña
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Eliana Ramos C
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Helena Avila-Arias
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
| | - Nicolás Molano-Gonzalez
- Study Center of Autoimmune Diseases (CREA), School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia
| | - Pedro F B Brandão
- Laboratorio de Microbiología Ambiental y Aplicada, Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia, Cra. 30 N. 45-03, Bogotá, Colombia
| | - Fabio Roldan
- Unidad de Saneamiento y Biotecnología Ambiental (USBA), Departamento de Biología, Facultad de Ciencias, Pontificia Universidad Javeriana, Cra. 7 N. 43-82, Bogotá, Colombia
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Lotufo GR, Belden JB, Fisher JC, Chen SF, Mowery RA, Chambliss CK, Rosen G. Accumulation and depuration of trinitrotoluene and related extractable and nonextractable (bound) residues in marine fish and mussels. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 210:129-136. [PMID: 26708767 DOI: 10.1016/j.envpol.2015.11.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 11/25/2015] [Accepted: 11/27/2015] [Indexed: 06/05/2023]
Abstract
To determine if trinitrotoluene (TNT) forms nonextractable residues in mussels (Mytilus galloprovincialis) and fish (Cyprinodon variegatus) and to measure the relative degree of accumulation as compared to extractable TNT and its major metabolites, organisms were exposed to water fortified with (14)C-TNT. After 24 h, nonextractable residues made up 75% (mussel) and 83% (fish) while TNT accounted for 2% of total radioactivity. Depuration half-lives for extractable TNT, aminodinitrotoluenes (ADNTs) and diaminonitrotoluenes (DANTs) were fast initially (<0.5 h), but slower for nonextractable residues. Nonextractable residues from organisms were identified as ADNTs and DANTs using 0.1 M HCL for solubilization followed by liquid chromatography-tandem mass spectrometry. Recovered metabolites only accounted for a small fraction of the bound residue quantified using a radiotracer likely because of low extraction or hydrolysis efficiency or alternative pathways of incorporation of radiolabel into tissue.
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Affiliation(s)
- Guilherme R Lotufo
- U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
| | - Jason B Belden
- Department of Integrative Biology, Oklahoma State University, Stillwater OK 74078, USA
| | - Jonathon C Fisher
- Department of Natural Sciences, Northwestern State University, Tahlequah, OK 74464, USA
| | - Shou-Feng Chen
- Department of Chemistry, Baylor University, Waco, TX 76798, USA
| | | | | | - Gunther Rosen
- Space and Naval Warfare (SPAWAR) Systems Center Pacific, 53475 Strothe Rd., San Diego, CA 92152, USA
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Shinkai Y, Nishihara Y, Amamiya M, Wakayama T, Li S, Kikuchi T, Nakai Y, Shimojo N, Kumagai Y. NADPH-cytochrome P450 reductase-mediated denitration reaction of 2,4,6-trinitrotoluene to yield nitrite in mammals. Free Radic Biol Med 2016; 91:178-87. [PMID: 26454083 DOI: 10.1016/j.freeradbiomed.2015.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/01/2015] [Accepted: 09/03/2015] [Indexed: 10/22/2022]
Abstract
While the biodegradation of 2,4,6-trinitrotoluene (TNT) via the release of nitrite is well established, mechanistic details of the reaction in mammals are unknown. To address this issue, we attempted to identify the enzyme from rat liver responsible for the production of nitrite from TNT. A NADPH-cytochrome P450 reductase (P450R) was isolated and identified from rat liver microsomes as the enzyme responsible for not only the release of nitrite from TNT but also formation of superoxide and 4-hydroxyamino-2,6-dinitrotoluene (4-HADNT) under aerobic conditions. In this context, reactive oxygen species generated during P450R-catalyzed TNT reduction were found to be, at least in part, a mediator for the production of 4-HADNT from TNT via formation of 4-nitroso-2,6-dinitrotoluene. P450R did not catalyze the formation of the hydride-Meisenheimer complex (H(-)-TNT) that is thought to be an intermediate for nitrite release from TNT. Furthermore, in a time-course experiment, 4-HADNT formation reached a plateau level and then declined during the reaction between TNT and P450R with NADPH, while the release of nitrite was subjected to a lag period. Notably, the produced 4-HADNT can react with the parent compound TNT to produce nitrite and dimerized products via formation of a Janovsky complex. Our results demonstrate for the first time that P450R-mediated release of nitrite from TNT results from the process of chemical interaction of TNT and its 4-electron reduction metabolite 4-HADNT.
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Affiliation(s)
- Yasuhiro Shinkai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yuya Nishihara
- Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Masahiro Amamiya
- Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Toshihiko Wakayama
- Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Song Li
- Doctoral Program in Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Tomohiro Kikuchi
- Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yumi Nakai
- Application and Research Center, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan
| | - Nobuhiro Shimojo
- Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Doctoral Program in Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Graduate School of Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; Doctoral Program in Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
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15
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Shinkai Y, Li S, Kikuchi T, Kumagai Y. Participation of metabolic activation of 2,4,6-trinitrotoluene to 4-hydroxylamino-2,6-dinitrotoluene in hematotoxicity. J Toxicol Sci 2015; 40:597-604. [DOI: 10.2131/jts.40.597] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Yasuhiro Shinkai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba
| | - Song Li
- Doctoral Program in Medical Sciences, University of Tsukuba
| | - Tomohiro Kikuchi
- Master’s program in Environmental Sciences, University of Tsukuba
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba
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16
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Solyanikova IP, Robota IV, Mazur DM, Lebedev AT, Golovleva LA. Application of Bacillus sp. strain VT-8 for decontamination of TNT-polluted sites. Microbiology (Reading) 2014. [DOI: 10.1134/s0026261714050257] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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17
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Khilyas IV, Ziganshin AM, Pannier AJ, Gerlach R. Effect of ferrihydrite on 2,4,6-trinitrotoluene biotransformation by an aerobic yeast. Biodegradation 2012; 24:631-44. [DOI: 10.1007/s10532-012-9611-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
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18
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McFarland CA, Talent LG, Quinn MJ, Bazar MA, Wilbanks MS, Nisanian M, Gogal RM, Johnson MS, Perkins EJ, Gust KA. Multiple environmental stressors elicit complex interactive effects in the western fence lizard (Sceloporus occidentalis). ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:2372-2390. [PMID: 22975894 DOI: 10.1007/s10646-012-0993-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/20/2012] [Indexed: 06/01/2023]
Abstract
Evaluation of multiple-stressor effects stemming from habitat degradation, climate change, and exposure to chemical contaminants is crucial for addressing challenges to ecological and environmental health. To assess the effects of multiple stressors in an understudied taxon, the western fence lizard (Sceloporus occidentalis) was used to characterize the individual and combined effects of food limitation, exposure to the munitions constituent 2,4,6-trinitrotoluene (TNT), and Plasmodium mexicanum (lizard malaria) infection. Three experimental assays were conducted including: Experiment I--TNT × Food Limitation, Experiment II--Food Limitation × Malaria Infection, and Experiment III--TNT × Malaria Infection. All experiments had a 30 day duration, the malaria treatment included infected and non infected control lizards, food limitation treatments included an ad libitum control and at least one reduced food ration and TNT exposures consisting of daily oral doses of corn oil control or a corn oil-TNT suspension at 5, 10, 20, 40 mg/kg/day. The individual stressors caused a variety of effects including: reduced feeding, reduced testes mass, anemia, increased white blood cell (WBC) concentrations and increased mass of liver, kidney and spleen in TNT exposures; reduced cholesterol, WBC concentrations and whole body, testes and inguinal fat weights given food limitation; and increased WBC concentrations and spleen weights as well as decreased cholesterol and testes mass in malaria infected lizards. Additive and interactive effects were found among certain stressor combinations including elimination of TNT-induced hormesis for growth under food limitation. Ultimately, our study indicates the potential for effects modulation when environmental stressors are combined.
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Affiliation(s)
- Craig A McFarland
- Health Effects Research Program, Toxicology Portfolio, U.S. Army Institute of Public Health, Aberdeen Proving Ground, MD 21010-5403, USA.
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19
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Lotufo GR. Whole-body and body-part-specific bioconcentration of explosive compounds in sheepshead minnows. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:301-306. [PMID: 21255837 DOI: 10.1016/j.ecoenv.2010.07.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 07/20/2010] [Accepted: 07/25/2010] [Indexed: 05/30/2023]
Abstract
Sheepshead minnows (Cyprinodon variegatus) were exposed to radiolabeled isotopes of the explosives 2,4,6-trinitrotoluene (TNT), exahydro-1,3,5-trinitro-1,3,5-triazine (commonly known as RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (commonly known as HMX), yielding the bioconcentration factors (BCF) of 3.3, 0.7, and 0.1 L kg(-1), respectively. For TNT, the body residue of transformation product exceeded that of the parent compound by factors of 1, 8, and 16 for total aminonitrotoluenes, total extractable compounds, and total transformation products, respectively, with substantial bioaccumulation of both non-identified extractable and unextractable (i.e., tissue-bound), compounds. In comparison, the sum body residues of RDX and HMX transformation products were <4 times higher than for parent compounds. The concentrations of RDX and HMX and their transformation products were similar among liver, viscera (excluding liver), gills, and body remains (integument and muscles), while 46% of the TNT transformation products resided in the liver, and 64% of the parent compound was in the viscera.
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Affiliation(s)
- Guilherme R Lotufo
- U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
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20
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McFarland CA, Quinn MJ, Boyce J, LaFiandra EM, Bazar MA, Talent LG, Johnson MS. Toxic effects of oral 2-amino-4,6-dinitrotoluene in the Western fence lizard (Sceloporus occidentalis). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2011; 159:466-473. [PMID: 21067851 DOI: 10.1016/j.envpol.2010.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 10/12/2010] [Accepted: 10/15/2010] [Indexed: 05/30/2023]
Abstract
The compound 2-amino-4,6-dinitrotoluene (2A-DNT) was evaluated under laboratory conditions in the Western fence lizard (Sceloporus occidentalis) to assess the potential for reptile toxicity. Oral LD(50) values were 1406 and 1867 mg/kg for male and female lizards, respectively. Based on responses from a 14-day subacute study, a 60-day subchronic experiment followed where lizards were orally dosed at 0, 5, 15, 20, 25, 30 mg/kg-d. At day 60, number of days and survivors, food consumption, and change in body weight were inversely related to dose. Signs of toxicity were characterized by anorexia and generalized cachexia. Significant adverse histopathology was observed in hepatic tissue at ≥ 15 mg/kg-d, consistent with hepatocellular transdifferentiation. Based on survival, loss of body weight, diminished food intake, changes in liver, kidney, and testes, and increased blood urea nitrogen, these data suggest a LOAEL of 15 mg/kg-d and a NOAEL of 5 mg/kg-d in S. occidentalis.
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Affiliation(s)
- Craig A McFarland
- US Army Public Health Command (Prov), Aberdeen Proving Ground, MD 21010, USA.
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21
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Ziganshin AM, Gerlach R, Naumenko EA, Naumova RP. Aerobic degradation of 2,4,6-trinitrotoluene by the yeast strain Geotrichum candidum AN-Z4. Microbiology (Reading) 2010. [DOI: 10.1134/s0026261710020086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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22
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Ziganshin AM, Naumova RP, Pannier AJ, Gerlach R. Influence of pH on 2,4,6-trinitrotoluene degradation by Yarrowia lipolytica. CHEMOSPHERE 2010; 79:426-433. [PMID: 20185159 DOI: 10.1016/j.chemosphere.2010.01.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 01/23/2010] [Accepted: 01/28/2010] [Indexed: 05/28/2023]
Abstract
The microbial reduction of the aromatic ring of 2,4,6-trinitrotoluene (TNT) can lead to its complete destruction. The acid-tolerant yeast Yarrowia lipolytica AN-L15 transformed TNT through hydride ion-mediated reduction of the aromatic ring (as the main pathway), resulting in the accumulation of nitrite and nitrate ions, as well as through nitro group reduction (as minor pathway), resulting in hydroxylamino- and aminoaromatics. TNT transformation depended on the yeasts' ability to acidify the culture medium through the production of organic acids. Aeration and a low medium buffer capacity favored yeast growth and resulted in rapid acidification of the medium, which influenced the rate and extent of TNT transformation. This is the first time that nitrate has been detected as a major product of microbial TNT degradation, and this work demonstrates the importance of pH on TNT biotransformation. The ability of Y. lipolytica AN-L15 to reduce the TNT aromatic ring to form TNT-hydride complexes, followed by their denitration, makes this strain a potential candidate for bioremediation of sites contaminated with explosives.
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Affiliation(s)
- Ayrat M Ziganshin
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
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23
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Nyanhongo GS, Schroeder M, Steiner W, Gübitz GM. Biodegradation of 2,4,6-trinitrotoluene (TNT): An enzymatic perspective. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420500090169] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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24
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Bell SC, Gayton-Ely M, Nida CM. Bioassays for bomb-makers: proof of concept. Anal Bioanal Chem 2009; 395:401-9. [PMID: 19484462 DOI: 10.1007/s00216-009-2851-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 04/29/2009] [Accepted: 05/12/2009] [Indexed: 11/29/2022]
Abstract
Clandestine bomb-makers are exposed to significant amounts of explosives and allied materials. As with any ingested xenobiotic substance, these compounds are subject to biotransformation. As such, the potential exists that characteristic suites of biomarkers may be produced and deposited in matrices that can be exploited for forensic and investigative purposes. However, before such assays can be developed, foundational data must be gathered regarding the toxicokinetics, fate, and transport of the resulting biomarkers within the body and in matrices such as urine, hair, nails, sweat, feces, and saliva. This report presents an in vitro method for simulation of human metabolic transformations using human liver microsomes and an assay applicable to representative nitro-explosives. Control and metabolized samples of TNT, RDX, HMX, and tetryl were analyzed using high-performance liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) and biomarkers identified for each. The challenges associated with this method arise from solubility issues and limitations imposed by instrumentation, specifically, modes of ionization.
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Affiliation(s)
- Suzanne C Bell
- Forensic Science & Chemistry, West Virginia University, 1600 University Avenue, Oglebay Hall, Room 208, Box 6121, Morgantown, WV 26506-6121, USA.
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25
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Della Torre C, Corsi I, Arukwe A, Valoti M, Focardi S. Interactions of 2,4,6-trinitrotoluene (TNT) with xenobiotic biotransformation system in European eel Anguilla anguilla (Linnaeus, 1758). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 71:798-805. [PMID: 18407354 DOI: 10.1016/j.ecoenv.2008.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Revised: 02/29/2008] [Accepted: 03/01/2008] [Indexed: 05/26/2023]
Abstract
The aim of the present study was to investigate the interaction of 2,4,6-trinitrotoluene (TNT) with liver biotransformation enzymes in European eel Anguilla anguilla (Linnaeus, 1758). Eels were exposed to 0.5, 1 and 2.5mg/l nominal concentrations of TNT for 6 and 24h. Modulation of CYP1A1, UDPGT and GST genes was investigated by real-time PCR. Total CYP450 content, NADPH cytochrome c reductase activity, CYP1A and CYP2B-like activities, such as EROD, MROD and BROD, as well as GST and UDPGT activities, were measured by biochemical assays. An in vitro study was performed on EROD in order to evaluate catalytic modulation by TNT. No modulation of the CYP1A1 gene or protein was observed in TNT-exposed eels. On the other hand, a significant decline of EROD and MROD activities was observed in vivo. An increase in NADPH cyt c reductase, and phase II enzymes (UDPGT and GST) were observed at both gene expression and activity levels. The overall results indicated that TNT is a potential competitive inhibitor of CYP1A activities. A TNT metabolic pathway involving NADPH cyt c reductase and phase II enzymes is also suggested.
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Affiliation(s)
- Camilla Della Torre
- Department of Environmental Sciences G. Sarfatti, University of Siena, Via Mattioli 4, 53100 Siena, Italy.
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26
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Abstract
2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT-exposed humans, notable toxic manifestations have included aplastic anaemia, toxic hepatitis, cataracts, hepatomegaly and liver cancer. Therefore, it is important to develop protection measures and to monitor workers involved in the clean-up of ammunition sites. Haemoglobin (Hb) adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urine metabolites of TNT, 4ADNT and 2ADNT were found in 22-50% of the exposed workers, but not in the control group. The exposed workers were wearing protective equipment. The levels of erythrocytes, haemoglobin, creatinine, serum glutamic pyruvic transaminase and lymphocyte levels were significantly lower in the exposed workers than in the non-exposed workers. The levels of blood urea and reticulocytes were significantly higher in the exposed workers than in the non-exposed workers. Headache (26%), mucous membrane irritation (16%), sick leave (18%), lassitude (8%), anxiety (6%), shortness of breath (3%), nausea (5%) and allergic reactions (8%) were reported by the exposed workers. In a further analysis the U-4ADNT levels and the Hb-adduct levels were compared to the blood parameter and the health effects. The blood parameters were not significantly different between the U-4ADNT positive and U-4ADNT-negative group. Headache, mucous membrane irritation, sick leave, lassitude, anxiety, shortness of breath and allergic reactions were statistically not different between the two groups. Also in the workers with Hb-4ADNT adducts no significant negative changes were seen in regards to the changes of the blood parameters or the health effects. According to the results of the present study, it appears that the blood parameter changes and the health effects are more influenced by other factors than by the internal exposure to TNT.
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Affiliation(s)
- Gabriele Sabbioni
- Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA 70112, USA.
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27
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Sabbioni G, Sepai O, Norppa H, Yan H, Hirvonen A, Zheng Y, Järventaus H, Bäck B, Brooks LR, Warren SH, Demarini DM, Liu YY. Comparison of biomarkers in workers exposed to 2,4,6-trinitrotoluene. Biomarkers 2008; 12:21-37. [PMID: 17438651 DOI: 10.1080/13547500600807012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT-exposed humans, notable toxic manifestations have included aplastic anaemia, toxic hepatitis, cataracts, hepatomegaly, and liver cancer. Therefore, methods were developed to biomonitor workers exposed to TNT. The workers were employed in a typical ammunition factory in China. The external dose (air levels and skin exposure), the internal dose (urinary metabolites), the biologically effective dose (haemoglobin adducts, urinary mutagenicity), biological effects (chromosomal aberrations and health effects), and individual susceptibility (genotypes of xenobiotic-metabolizing enzymes) were determined. Haemoglobin-adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urinary metabolites of TNT, 4ADNT and 2ADNT, were found in all workers and in some controls. The levels of the haemoglobin-adducts or the urinary metabolites correlated weakly with the skin or air levels of TNT. The urinary mutagenicity determined in a subset of workers correlated strongly with the levels of 4ADNT and 2ADNT in urine. The haemoglobin-adducts correlated moderately with the urinary metabolites and with the urinary mutagenicity. The genotypes of glutathione S-transferases (GSTM1, GSTT1, GSTP1) and N-acetyltransferases (NAT1, NAT2) were determined. In general, the genotypes did not significantly influence the haemoglobin-adduct levels and the urine metabolite levels. However, TNT-exposed workers who carried the NAT1 rapid acetylator genotype showed an increase in urinary mutagenicity and chromosomal aberrations as compared with slow acetylators. The haemoglobin adduct 4ADNT was significantly associated with a risk of hepatomegaly, splenomegaly and cataract; urine metabolites and genotypes were not associated with health effects. These results indicate that a set of well-selected biomarkers may be more informative regarding exposure and effect than routinely performed chemical measurements of pollutants in the air or on the skin.
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Affiliation(s)
- G Sabbioni
- Institute of Environmental and Occupational Toxicology, Airolo, Switzerland.
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28
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Della Torre C, Corsi I, Arukwe A, Alcaro L, Amato E, Focardi S. Effects of 2,4,6-trinitrotoluene (TNT) on phase I and phase II biotransformation enzymes in European eel Anguilla anguilla (Linnaeus, 1758). MARINE ENVIRONMENTAL RESEARCH 2008; 66:9-11. [PMID: 18378298 DOI: 10.1016/j.marenvres.2008.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The aim of this study was to investigate effects of the explosive 2,4,6-trinitrotoluene (TNT) on liver drug metabolizing genes and enzymes in the European eel Anguilla anguilla as a model fish species. Eels were exposed in vivo for 6h and 24h to 0.5, 1 and 2.5mg/L nominal concentrations of TNT. Expression of CYP1A, glutathione-S-transferase (pi-class; GST) and uridine-diphosphate glucuronosyltransferase (1-family) (UDPGT) genes was investigated by RT-PCR, and 7-ethoxy- and 7-methoxyresorufin-O-dealkylases (EROD, MROD), NADPH cyt c reductase (NADPH red), UDPGT and GST enzyme activities were measured by biochemical assays. An in vitro study was also performed, measuring only EROD activity. TNT exposure produced no modulation of CYP1A transcript expression while a significant inhibition of EROD enzyme activity was observed and confirmed in vitro. UDPGT transcript increased dose-dependently only at 6h while the UDPGT activity tended to increase dose-dependently at 24h. GST gene expression increased after 24h and significant increases of GST activity were observed both at 6 and 24h only at the highest TNT concentration. An increase of NADPH red activity was observed at 24h. Our results seem to indicate an inhibitory effect of TNT on CYP1A-dependent catalytic activities and a possible involvement of phase II enzymes as well as NADPH red in TNT metabolism in eels.
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Affiliation(s)
- Camilla Della Torre
- Department of Environmental Sciences G Sarfatti, University of Siena, Via Mattioli 4, Siena, Italy.
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Sims JG, Steevens JA. The role of metabolism in the toxicity of 2,4,6-trinitrotoluene and its degradation products to the aquatic amphipod Hyalella azteca. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2008; 70:38-46. [PMID: 17980428 DOI: 10.1016/j.ecoenv.2007.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 07/18/2007] [Accepted: 08/25/2007] [Indexed: 05/06/2023]
Abstract
Toxicological data on the effects of the explosive, 2,4,6-trinitrotoluene (TNT), and its degradation products suggests an unpredictable toxicological response in aquatic organisms. Several studies suggest TNT becomes more toxic as it degrades while others suggest TNT becomes less toxic. This study focused on the toxicity of TNT and several degradation products as well as the role of oxidative metabolism in the toxicity of TNT. The aquatic invertebrate Hyalella azteca was used to evaluate the toxicity of TNT and four of its degradation products. The most reduced degradation product, 2,4-diamino, 6-nitrotoluene (2,4-DANT) was the most toxic to H. azteca. However, 2,4-DANT was only a minor metabolite in H. azteca. The influence of metabolism on the toxicokinetics of TNT was assessed indirectly through the use of a CYP450 inducer and inhibitor. Treatment of organisms with beta-napthoflavone (BNF), a CYP450 inducer, increased the toxicity of TNT and increased the rate of elimination and metabolism of TNT. Similar to BNF, organisms treated with clotrimazole (CTZ), a CYP450 inhibitor, resulted in increased toxicity and TNT metabolism. It is likely the ability to metabolize or bioactivate TNT to a more reactive intermediate plays a significant role in the sensitivity of organisms to TNT.
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Affiliation(s)
- Jerre G Sims
- US Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
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Smith DJ, Craig AM, Duringer JM, Chaney RL. Absorption, tissue distribution, and elimination of residues after 2,4,6-trinitro[14C]toluene administration to sheep. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:2563-2569. [PMID: 18504997 DOI: 10.1021/es702601n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The compound 2,4,6-trinitrotoluene (TNT) is a persistent contaminant of some industrial and military sites. Biological bioremediation techniques typically rely on the immobilization of TNT reduction products rather than on TNT mineralization. We hypothesized that sheep ruminal microbes would be suitable for TNT destruction after phytoremediation of TNT-contaminated soils by cool-season grasses. Therefore we investigated the fate of [14C]TNT in ruminating sheep to determine the utility of ruminant animals as a portion of the bioremediation process. Three wether sheep were dosed with 35.5 mg each of dietary unlabeled TNT for 21 consecutive days. On day 22 sheep (41.9 +/- 3.0 kg) were orally dosed with 35.5 mg of [14C]TNT (129 microCi; 99.1% radiochemical purity). Blood, urine, and feces were collected at regular intervals for 72 h. At slaughter, tissues were quantitatively collected. Tissues and blood were analyzed for total radioactive residues (TRR); excreta were analyzed for TRR, bound residues, and TNT metabolites. Plasma radioactivity peaked within 1 h of dosing and was essentially depleted within 18 h. Approximately 76% of the radiocarbon was excreted in feces, 17% in urine, with 5% being retained in the gastrointestinal tract and 1% retained in tissues. Parent TNT, dinitroamino metabolites, and diaminonitro metabolites were not detected in excreta. Ruminal and fecal radioactivity was essentially nonextractable using ethyl acetate, acetone, and methanol; covalent binding of fecal radioactive residues was evenly distributed among extractable organic molecules (i.e., soluble organic matter, soluble carbohydrate, protein, lipid, and nucleic acid fractions) and undigested fibers (cellulose, hemicellulose, and lignin). This study demonstrated that TNT reduction within the ruminant gastrointestinal tract leads to substantial immobilization of residues to organic matter, a fate similar to TNT in other strongly reducing environments.
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Affiliation(s)
- D J Smith
- Animal Metabolism-Agricultural Chemicals Research Unit, USDA ARS, 1605 Albrecht Blvd. Fargo, North Dakota, 58105-5674, USA.
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Smets BF, Yin H, Esteve-Nuñez A. TNT biotransformation: when chemistry confronts mineralization. Appl Microbiol Biotechnol 2007; 76:267-77. [PMID: 17534614 DOI: 10.1007/s00253-007-1008-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
Our understanding of the genetics and biochemistry of microbial 2,4,6-trinitrotoluene (TNT) biotransformation has advanced significantly during the past 10 years, and biotreatment technologies have developed. In this review, we summarize this new knowledge. A number of enzyme classes involved in TNT biotransformation include the type I nitroreductases, the old yellow enzyme family, a respiration-associated nitroreductase, and possibly ring hydroxylating dioxygenases. Several strains harbor dual pathways: nitroreduction (reduction of the nitro group in TNT to a hydroxylamino and/or amino group) and denitration (reduction of the aromatic ring of TNT to Meisenheimer complexes with nitrite release). TNT can serve as a nitrogen source for some strains, and the postulated mechanism involves ammonia release from hydroxylamino intermediates. Field biotreatment technologies indicate that both stimulation of microbial nitroreduction and phytoremediation result in significant and permanent immobilization of TNT via its metabolites. While the possibility for TNT mineralization was rekindled with the discovery of TNT denitration and oxygenolytic and respiration-associated pathways, further characterization of responsible enzymes and their reaction mechanisms are required.
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Affiliation(s)
- Barth F Smets
- Institute of Environment and Resources, Technical University of Denmark, Bygningstorvet, Bldg 115, 2800 Kgs. Lyngby, Denmark.
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Claus H, Perret N, Bausinger T, Fels G, Preuss J, König H. TNT transformation products are affected by the growth conditions of Raoultella terrigena. Biotechnol Lett 2006; 29:411-9. [PMID: 17136570 DOI: 10.1007/s10529-006-9244-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Accepted: 10/19/2006] [Indexed: 10/23/2022]
Abstract
High concentrations of 2,4,6-trinitrotoluene (TNT) and related nitroaromatic compounds are commonly found in soil and groundwater at former explosive plants. The bacterium, Raoultella terrigena strain HB, isolated from a contaminated site, converts TNT into the corresponding amino products. Radio-HPLC analysis with [(14)C]TNT identified aminodinitrotoluene, diaminonitrotoluene and azoxy-dimers as the main metabolites. Transformation rate and the type of metabolites that predominated in the culture medium and within the cells were significantly influenced by the culture conditions. The NAD(P)H-dependent enzymatic reduction of nitro-substituted compounds by cell-free extracts of R. terrigena was evaluated in vitro.
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Affiliation(s)
- Harald Claus
- Johannes Gutenberg-University Mainz, Institute of Microbiology and Wine Research, Mainz, Germany.
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Houston JG, Lotufo GR. Dietary exposure of fathead minnows to the explosives TNT and RDX and to the pesticide DDT using contaminated invertebrates. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2006; 2:286-92. [PMID: 16705829 PMCID: PMC3810632 DOI: 10.3390/ijerph2005020012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Explosive compounds have been released into the environment during manufacturing, handling, and usage procedures. These compounds have been found to persist in the environment and potentially promote detrimental biological effects. The lack of research on bioaccumulation and bioconcentration and especially dietary transfer on aquatic life has resulted in challenges in assessing ecological risks. The objective of this study was to investigate the potential trophic transfer of the explosive compounds 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using a realistic freshwater prey/predator model and using dichlorodiphenyltrichloroethane (DDT), a highly bioaccumulative compound, to establish relative dietary uptake potential. The oligochaete worm Lumbriculus variegatus was exposed to 14C-labeled TNT, RDX or DDT for 5 hours in water, frozen in meal-size packages and subsequently fed to individual juvenile fathead minnows (Pimephales promelas). Fish were sampled for body residue determination on days 1, 2, 3, 4, 7, and 14 following an 8-hour gut purging period. Extensive metabolism of the parent compound in worms occurred for TNT but not for RDX and DDT. Fish body residue remained relatively unchanged over time for TNT and RDX, but did not approach steady-state concentration for DDT during the exposure period. The bioaccumulation factor (concentration in fish relative to concentration in worms) was 0.018, 0.010, and 0.422 g/g for TNT, RDX and DDT, respectively, confirming the expected relatively low bioaccumulative potential for TNT and RDX through the dietary route. The experimental design was deemed successful in determining the potential for trophic transfer of organic contaminants via a realistic predator/prey exposure scenario.
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Affiliation(s)
- Jerre G. Houston
- U.S. Army Engineer Research and Development Center, Waterways Experiment Station, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Guilherme R. Lotufo
- U.S. Army Engineer Research and Development Center, Waterways Experiment Station, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
- Correspondence to Dr. Guilherme Lotufo.
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Torre CD, Corsi I, Alcaro L, Amato E, Focardi S. The involvement of cytochrome P450 system in the fate of 2,4,6-trinitrotoluene (TNT) in European eel [Anguilla anguilla (Linnaeus, 1758)]. Biochem Soc Trans 2006; 34:1228-30. [PMID: 17073791 DOI: 10.1042/bst0341228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TNT (2,4,6-trinitrotoluene) was the most common nitro aromatic explosive available in World War II ammunitions. The presence of ordnance dumped at sea might represent a great concern for marine species living close to dumping sites and the toxicological properties of the chemicals released into the marine environments need to be evaluated. The aim of the present study is to investigate the involvement of CYP (cytochrome P450) system in the metabolism of TNT in marine organisms by using the European eel [Anguilla anguilla (Linnaeus, 1758)] as model species. In vivo exposure to sublethal concentration of TNT (0.5, 1 and 2.5 mg/l) leads to a significant decrease in the phase I CYP1A catalytic activities such as EROD (7-ethoxyresorufin-O-de-ethylase) and MROD (7-methoxyresorufin-O-de-ethylase). On the opposite, a significant increase in NADPH cytochrome c reductase activity as well as phase II UDP-glucuronosyltransferase activity is observed. An inhibition at enzyme level is hypothesized for both CYP1A enzymes, also confirmed by a similar decrease observed after in vitro exposure. An active role of NADPH cytochrome c reductase and phase II enzymes in the TNT metabolism may also be hypothesized.
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Affiliation(s)
- C Della Torre
- Department of Environmental Sciences 'G. Sarfatti', University of Siena, Via Mattioli, 4, 53100 Siena, Italy.
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Bolt HM, Degen GH, Dorn SB, Plöttner S, Harth V. Genotoxicity and potential carcinogenicity of 2,4,6-TNT trinitrotoluene: structural and toxicological considerations. REVIEWS ON ENVIRONMENTAL HEALTH 2006; 21:217-28. [PMID: 17243348 DOI: 10.1515/reveh.2006.21.4.217] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Environmental contamination with 2,4,6-TNT (trinitrotoluene) represents a worldwide problem. Concern for carcinogenicity can be derived from chemically related compounds, especially the dinitrotoluenes. In the metabolism of TNT, the reductive routes are preponderant. The main urinary metabolites of TNT are 4-amino-2,6-dinitrotoluene and 2-amino-4,6-dinitrotoluene. In humans exposed to TNT, the formation of hemoglobin adducts of the amino-dinitrotoluenes is in general concordance with the ratio of urinary excretion. The variations in quantities of excreted metabolites among the different occupational cohorts studied are likely explained by the different routes of exposure to TNT, including dermal uptake. Most studies show that urinary excretion of the amino-dinitrotoluenes (4-amino-dinitrotoluene plus 2-amino-dinitrotoluene) in a range of 1 to 10 mg L(-1) (5-50 microM) are not uncommon--for instance in persons employed with the disposal of military waste. Trinitotoluene is mutagenic in Salmonella typhimurium strains TA98 and TA100, with and without exogenous metabolic activation. Mutagenic activity has been found in urine from workers who were occupationally exposed to TNT. An unpublished 2-year study was reported in 1984 by the IIT Research Institute, Chicago, IL. Fischer 344 rats were fed diets containing 0.4, 2.0, 10, or 50 mg/kg TNT per day. In the urinary bladder, hyperplasia (12 of 47 animals p < .01) and carcinoma (11 of 47 animals, p < .05) were observed at significant levels in high-dose (50 mg kg(-1)) females and in one or two females, respectively, at 10 mg kg(-1). Taking all the available evidence together, the appropriate precautions should be taken.
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Affiliation(s)
- Hermann M Bolt
- Institut für Arbeitsphysiologie an der Universität Dortmund (IfADo), Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
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Ek H, Dave G, Nilsson E, Sturve J, Birgersson G. Fate and effects of 2,4,6-trinitrotoluene (TNT) from dumped ammunition in a field study with fish and invertebrates. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2006; 51:244-52. [PMID: 16783622 DOI: 10.1007/s00244-005-0117-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Accepted: 10/31/2005] [Indexed: 05/10/2023]
Abstract
2,4,6-Trinitrotoluene (TNT) is the major explosive ingredient in ammunition dumped into lakes and sea after World War II. The aim of the present field study was to study the fate and effect of TNT and its degradation products from dumped ammunition. Artillery shells were cleaved longitudinally to expose TNT and placed in open boxes filled with sediment, and then placed at the sea bottom. Sediment samples were taken in each box at the start and after 3, 9, 13, 20, 24, 33, and 36 months, and the sediments were tested for toxicity with bioassays using Nitocra spinipes (96 h), Hyalella azteca (96 h), and Daphnia magna (24 and 48 h). The result from the bioassays showed no impact of dumped ammunition on the survival of H. azteca and mobility of D. magna. Bioassays with N. spinipes showed significant differences in toxicity between control boxes and boxes with shells after 9 months and thereafter. The mean mortality (+/- SD) of N. spinipes in boxes with shells was 63 +/- 22%, and the mortality in control boxes was 23 +/- 17%. No continuous increase in sediment toxicity over time was found. After 3 years, cages with European flounder (Platichtys flesus) and blue mussels (Mytilus edulis) were attached to the boxes. The fish were examined for biochemical and physiological effects 8 weeks later. Exposure to ammunition, which had rested on the sea bottom 3 years, caused no significant effects on body indices, hematological variables, and detoxification and antioxidant enzymes activities in the flounder. The sediment, bile, and blood plasma of exposed fish, and hepatopancreas of exposed mussels, contained no detectable levels of TNT and its metabolites. Only minor disappearance of TNT from the shells could be detected by visual inspection on site (by scuba divers). This study suggests that the survival of sensitive benthic organisms, e.g., N. spinipes, might be negatively affected at an ammunition dumping site.
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Affiliation(s)
- Helene Ek
- Department of Applied Environmental Science, Göteborg University, Box 464, SE-405 30, Göteborg, Sweden.
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Ek H, Dave G, Sturve J, Almroth BC, Stephensen E, Förlin L, Birgersson G. Tentative biomarkers for 2,4,6-trinitrotoluene (TNT) in fish (Oncorhynchus mykiss). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2005; 72:221-230. [PMID: 15820102 DOI: 10.1016/j.aquatox.2005.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2004] [Revised: 12/22/2004] [Accepted: 01/05/2005] [Indexed: 05/24/2023]
Abstract
2,4,6-Trinitrotoluene (TNT) is the major explosive in ammunition dumped into lakes and the sea after World War II. To identify useful biomarkers of TNT-exposure for forthcoming fish monitoring studies at ammunition dumping sites, rainbow trout (Oncorhynchus mykiss) were intraperitoneal (i.p.) injected with TNT in peanut oil at doses of 0, 100, 200 or 400 mg TNT/kg body weight and sampled 72 h later. The study covered blood parameters, and hepatic antioxidant and detoxifying enzymes. Fish treated with TNT had an increased glutathione S-transferase (GST) activity and glutathione reductase (GR) activity, and a decreased percentage of oxidised glutathione (%GSSG) compared to the control group. In addition to increased methemoglobin, the increased glutathione and glutathione dependent enzyme activities indicate that TNT oxidises macromolecules and activates antioxidant defence systems which may be useful as general biomarkers of TNT-exposure. The fish bile was analysed for TNT and its metabolites by gas chromatography-mass spectrometry (GC-MS), and the toxicity of the bile was determined with the cladoceran Ceriodaphnia dubia. A dose-dependent increase in TNT, 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) was found in the hydrolysed bile of the TNT-treated fish. These results indicate that the fish are able to detoxify and excrete TNT and suggest that the detection of TNT, 2-ADNT and 4-ADNT in bile may be suitable as a direct marker of exposure to TNT.
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Affiliation(s)
- Helene Ek
- Department of Applied Environmental Science, Göteborg University, Box 464, SE-405 30 Göteborg, Sweden.
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Sabbioni G, Liu YY, Yan H, Sepai O. Hemoglobin adducts, urinary metabolites and health effects in 2,4,6-trinitrotoluene exposed workers. Carcinogenesis 2005; 26:1272-9. [PMID: 15817613 DOI: 10.1093/carcin/bgi078] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT exposed humans, the notable toxic manifestations have included aplastic anemia, toxic hepatitis, cataract, hepatomegaly and liver cancer. Therefore, we developed methods to biomonitor workers exposed to TNT. The workers were employed in a typical ammunition factory in China. The controls were recruited from the same factory. We determined hemoglobin (Hb) adducts and urine metabolites of TNT. Hb-adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urine metabolites of TNT, 4ADNT and 2ADNT were found in all the workers and in a few controls. 4ADNT was the main product. Although the levels of 2ADNT correlated well with 4ADNT, 2ADNT was not found in all the samples. Therefore, 4ADNT was the best marker of exposure for Hb-adducts and urine metabolites. The levels of the urine metabolites and Hb-adducts were related to the health status of the workers. The Hb-adduct 4ADNT was statistically significantly associated with risk of hepatomegaly, splenomegaly and cataract. The odds ratio (OR) for cataract, splenomegaly and hepatomegaly were 6.4 [95% confidence interval (CI) = 1.4-29.6], 9.6 (1.1-85.3) and 7.6 (1.3-43.7), respectively. No correlation was found between urine metabolites and health effects. These results were tested for confounding factors like age, workyears, smoker status, smoke years, cigarettes per day and hepatitis B status using stepwise forward logistic regression analysis. In the case of splenomegaly, hepatitis B status is a confounder. In the case of cataract, age is a confounder. The Hb-adduct, 4ADNT, is a good biomarker of exposure and biomarker of biological effect.
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Affiliation(s)
- Gabriele Sabbioni
- Institute of Environmental and Occupational Toxicology, Casella Postale 108, 6780 Airolo, Switzerland.
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Belden JB, Ownby DR, Lotufo GR, Lydy MJ. Accumulation of trinitrotoluene (TNT) in aquatic organisms: part 2--Bioconcentration in aquatic invertebrates and potential for trophic transfer to channel catfish (Ictalurus punctatus). CHEMOSPHERE 2005; 58:1161-1168. [PMID: 15667837 DOI: 10.1016/j.chemosphere.2004.09.058] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 09/08/2004] [Accepted: 09/30/2004] [Indexed: 05/24/2023]
Abstract
The potential of TNT to accumulate in aquatic organisms was assessed by determining bioconcentration factors for TNT and TNT biotransformation products using two benthic invertebrates (Chironomus tentans and Lumbriculus variegatus), and by determining the bioaccumulation factor of TNT and TNT biotransformation products due to TNT exposure via feeding for channel catfish (Ictalurus punctatus). In all three species, TNT was rapidly biotransformed resulting in minimal accumulation. The bioconcentration factors for parent TNT ranged from 3 to 4 ml g(-1) for the invertebrates studied, while the TNT bioaccumulation factor for catfish via oral exposure of food pellets was 2.4x10(-5) g g(-1) based on the concentration of TNT in the food pellet. As indicated by this small bioaccumulation factor, TNT accumulation in channel catfish through trophic transfer would be negligible compared to aqueous exposure (previously reported BCF of 0.79 ml g(-1)). TNT extractable biotransformation products accumulated to a greater degree than parent TNT for all three species. In addition, a large fraction of the radioactivity within all three species resisted solvent extraction. The highest bioconcentration factors occurred in L. variegatus with extractable radioactivity measuring 76 ml g(-1) and total radioactivity measuring 216 ml g(-1). Because the bioaccumulation of TNT is very low compared to the bioaccumulation of its biotransformation products, further research including identifying and determining the relative toxicities of these biotransformation products is necessary to fully evaluate the environmental risk posed by exposure to TNT.
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Affiliation(s)
- Jason B Belden
- Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511, USA
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Ownby DR, Belden JB, Lotufo GR, Lydy MJ. Accumulation of trinitrotoluene (TNT) in aquatic organisms: part 1--Bioconcentration and distribution in channel catfish (Ictalurus punctatus). CHEMOSPHERE 2005; 58:1153-1159. [PMID: 15667836 DOI: 10.1016/j.chemosphere.2004.09.059] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 09/08/2004] [Accepted: 09/30/2004] [Indexed: 05/24/2023]
Abstract
Little is currently known regarding the toxicokinetics of TNT in fish. In the present study, the bioconcentration and distribution of trinitrotoluene (TNT) and TNT biotransformation products was investigated in juvenile channel catfish by exposing catfish to 14C-labeled TNT in water. Uptake experiments showed relatively fast rates (k(u)=10.1 ml g(-1) h(-1)) for TNT from the water; however, bioconcentration factors for TNT were low (0.79 ml g(-1)) due to rapid biotransformation and potential elimination of TNT. Accumulation of extractable radioactivity (TNT and all extractable biotransformation products) was much greater (BCF=10.5 ml g(-1)) than that for parent compound. TNT (parent compound) bioconcentrated to the greatest extent in the gills of the fish, while total radioactivity bioconcentrated to the greatest extent in the viscera. Residual portions of the fish that contained muscle and skin had lower concentrations of TNT than the whole fish, indicating that ingestion of fish fillets would result in decreased exposure to human consumers. Although the bioconcentration potential of TNT is very low, future research needs to be conducted to identify the biotransformation products that make up most of the radioactivity in exposed fish and evaluate their potential to promote toxicity.
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Affiliation(s)
- David R Ownby
- Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, Carbondale, Illinois 62901-6511, USA
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Sarlauskas J, Nemeikaite-Ceniene A, Anusevicius Z, Miseviciene L, Julvez MM, Medina M, Gomez-Moreno C, Cenas N. Flavoenzyme-catalyzed redox cycling of hydroxylamino- and amino metabolites of 2,4,6-trinitrotoluene: implications for their cytotoxicity. Arch Biochem Biophys 2004; 425:184-92. [PMID: 15111126 DOI: 10.1016/j.abb.2004.02.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 02/19/2004] [Indexed: 11/24/2022]
Abstract
The toxicity of 2,4,6-trinitrotoluene (TNT), a widespread environmental contaminant, is exerted through its enzymatic redox cycling and/or covalent binding of its reduction products to proteins and DNA. In this study, we examined the possibility of another cytotoxicity mechanism of the amino- and hydroxylamino metabolites of TNT, their flavoenzyme-catalyzed redox cycling. The above compounds acted as redox-cycling substrates for single-electron transferring NADPH:cytochrome P-450 reductase (P-450R) and ferredoxin:NADP(+) reductase (FNR), as well as substrates for the two-electron transferring flavoenzymes rat liver NAD(P)H:quinone oxidoreductase (NQO1) and Enterobacter cloacae NAD(P)H:nitroreductase (NR). Their reactivity in P-450R-, FNR-, and NR-catalyzed reactions increased with an increase in their single-electron reduction potential (E(1)(7)) or the decrease in the enthalpy of free radical formation. The cytotoxicity of the amino- and hydroxylamino metabolites of TNT towards bovine leukemia virus-transformed lamb kidney fibroblasts (line FLK) was partly prevented by the antioxidant N,N'-diphenyl-p-phenylene diamine and desferrioxamine, and potentiated by 1,3-bis-(2-chloroethyl)-1-nitrosourea, thus pointing to the involvement of oxidative stress. In general, their cytotoxicity increased with an increase in their electron accepting properties, or their reactivity towards the single-electron transferring FNR and P-450R. Thus, our data imply that the flavoenzyme-catalyzed redox cycling of amino and hydroxylamino metabolites of TNT may be an important factor in their cytotoxicity.
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Affiliation(s)
- Jonas Sarlauskas
- Institute of Biochemistry, Sector of Xenobiotics Biochemistry, MokslininkuSt. 12, Vilnius 2600, Lithuania
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Lewis TA, Newcombe DA, Crawford RL. Bioremediation of soils contaminated with explosives. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2004; 70:291-307. [PMID: 15016438 DOI: 10.1016/j.jenvman.2003.12.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2002] [Revised: 12/09/2003] [Accepted: 12/09/2003] [Indexed: 05/24/2023]
Abstract
The large-scale industrial production and processing of munitions such as 2,4,6-trinitrotoluene (TNT) over the past 100 years led to the disposal of wastes containing explosives and nitrated organic by-products into the environment. In the US, the Army alone has estimated that over 1.2 million tons of soil have been contaminated with explosives, and the impact of explosives contamination in other countries is of similar magnitude. In recent years, growing concern about the health and ecological threats posed by man-made chemicals have led to studies of the toxicology of explosives, which have identified toxic and mutagenic effects of the common military explosives and their transformation products (Bruns-Nagel et al., 1999a; Fuchs et al., 2001; Homma-Takeda et al., 2002; Honeycutt et al., 1996; Rosenblatt et al., 1991; Spanggord et al., 1982; Tan et al., 1992 and Won et al., 1976). Because the cleanup of areas contaminated by explosives is now mandated because of public health concerns, considerable effort has been invested in finding economical remediation technologies. Biological treatment processes are often considered, since these are usually the least expensive means of destroying organic pollution. This review examines the most important groups of chemicals that must be treated at sites contaminated by explosives processing, the chemical and biological transformations they undergo, and commercial processes developed to exploit these transformations for treatment of contaminated soil. We critically examine about 150 papers on the topic, including approximately 60 published within the past 5 years.
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Affiliation(s)
- Thomas A Lewis
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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Van Aken B, Agathos SN. Biodegradation of nitro-substituted explosives by white-rot fungi: a mechanistic approach. ADVANCES IN APPLIED MICROBIOLOGY 2002; 48:1-77. [PMID: 11677677 DOI: 10.1016/s0065-2164(01)48000-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- B Van Aken
- Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, USA
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Riefler RG, Smets BF. NAD(P)H:flavin mononucleotide oxidoreductase inactivation during 2,4,6-trinitrotoluene reduction. Appl Environ Microbiol 2002; 68:1690-6. [PMID: 11916686 PMCID: PMC123853 DOI: 10.1128/aem.68.4.1690-1696.2002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria readily transform 2,4,6-trinitrotoluene (TNT), a contaminant frequently found at military bases and munitions production facilities, by reduction of the nitro group substituents. In this work, the kinetics of nitroreduction were investigated by using a model nitroreductase, NAD(P)H:flavin mononucleotide (FMN) oxidoreductase. Under mediation by NAD(P)H:FMN oxidoreductase, TNT rapidly reacted with NADH to form 2-hydroxylamino-4,6-dinitrotoluene and 4-hydroxylamino-2,6-dinitrotoluene, whereas 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene were not produced. Progressive loss of activity was observed during TNT reduction, indicating inactivation of the enzyme during transformation. It is likely that a nitrosodinitrotoluene intermediate reacted with the NAD(P)H:FMN oxidoreductase, leading to enzyme inactivation. A half-maximum constant with respect to NADH, K(N), of 394 microM was measured, indicating possible NADH limitation under typical cellular conditions. A mathematical model that describes the inactivation process and NADH limitation provided a good fit to TNT reduction profiles. This work represents the first step in developing a comprehensive enzyme level understanding of nitroarene biotransformation.
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Affiliation(s)
- R Guy Riefler
- Department of Civil Engineering, Ohio University, Athens, Ohio 45701, USA.
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Cenas N, Nemeikaite-Ceniene A, Sergediene E, Nivinskas H, Anusevicius Z, Sarlauskas J. Quantitative structure-activity relationships in enzymatic single-electron reduction of nitroaromatic explosives: implications for their cytotoxicity. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1528:31-8. [PMID: 11514095 DOI: 10.1016/s0304-4165(01)00169-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanisms of cytotoxicity of polynitroaromatic explosives, an important group of environmental pollutants, remain insufficiently studied so far. We have found that the rate constants of single-electron enzymatic reduction, and the enthalpies of single-electron reduction of nitroaromatic compounds (DeltaHf(ArNO(2)(-*)), obtained by quantum mechanical calculation, may serve as useful tools for the analysis of cytotoxicity of nitroaromatic explosives with respect to the possible involvement of oxidative stress. The single-electron reduction rate constants of a number of explosives including 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenyl-N-methylnitramine (tetryl), and model nitroaromatic compounds by ferredoxin:NADP(+) reductase (FNR, EC 1.18.1.2) and NADPH:cytochrome P-450 reductase (P-450R, EC 1.6.2.4) increased with a decrease in DeltaHf(ArNO(2)(-*)). This indicates that the reduction rates are determined by the electron transfer energetics, but not by the particular structure of the explosives. The cytotoxicity of explosives to bovine leukemia virus-transformed lamb kidney fibroblasts (line FLK) increased with a corresponding increase in their reduction rate constant by P-450R and FNR, or with a decrease in their DeltaHf(ArNO(2)(-*)). This points to an importance of oxidative stress in the toxicity of explosives in this cell line, which was further evidenced by the protective effects of desferrioxamine and the antioxidant N,N'-diphenyl-p-phenylene diamine, and an increase in lipid peroxidation. DT-diaphorase (EC 1.6.99.2) exerted a minor and equivocal role in the cytotoxicity of explosives to FLK cells.
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Affiliation(s)
- N Cenas
- Institute of Biochemistry, Vilnius, Lithuania.
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Núñez-Vergara LJ, Bonta M, Navarrete-Encina P, Squella J. Electrochemical characterization of ortho and meta-nitrotoluene derivatives in different electrolytic media. Free radical formation. Electrochim Acta 2001. [DOI: 10.1016/s0013-4686(01)00629-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kumagai Y, Wakayama T, Lib S, Shinohara A, Iwamatsu A, Sun G, Shimojo N. Zeta-crystallin catalyzes the reductive activation of 2,4,6-trinitrotoluene to generate reactive oxygen species: a proposed mechanism for the induction of cataracts. FEBS Lett 2000; 478:295-8. [PMID: 10930585 DOI: 10.1016/s0014-5793(00)01841-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Exposure to 2,4,6-trinitrotoluene (TNT) has been shown to cause induction of cataract in which oxidative stress plays a critical role. From bovine lens we purified to homogeneity and identified an enzyme that catalyzes the reduction of TNT, resulting in the production of reactive oxygen species. The final preparation of TNT reductase showed a single band with a subunit molecular weight of 38 kDa on SDS-PAGE. Sequence data from peptides obtained by digestion with lysylendopeptidase Achromobacter protease I (API) revealed that TNT reductase is identical to zeta-crystallin. Superoxide anions were formed during reduction of TNT by zeta-crystallin, though negligible enzyme activity or protein content for superoxide dismutase, a superoxide scavenging enzyme, was found in the lens. Thus, the present results suggest that the induction of cataracts by TNT may be associated with increased oxidative stress, as a result of reductive activation of TNT generating superoxide anions, there being minimal antioxidant enzyme activity for defense against reactive oxygen species exogenously produced in the lens.
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Affiliation(s)
- Y Kumagai
- Department of Environment Medicine, Institute of Community Medicine, Master's Program in Environmental Sciences, Tsukuba University, Ibaraki, Japan.
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Vorbeck C, Lenke H, Fischer P, Spain JC, Knackmuss HJ. Initial reductive reactions in aerobic microbial metabolism of 2,4,6-trinitrotoluene. Appl Environ Microbiol 1998; 64:246-52. [PMID: 16349484 PMCID: PMC124701 DOI: 10.1128/aem.64.1.246-252.1998] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/1997] [Accepted: 11/03/1997] [Indexed: 11/20/2022] Open
Abstract
Because of its high electron deficiency, initial microbial transformations of 2,4,6-trinitrotoluene (TNT) are characterized by reductive rather than oxidation reactions. The reduction of the nitro groups seems to be the dominating mechanism, whereas hydrogenation of the aromatic ring, as described for picric acid, appears to be of minor importance. Thus, two bacterial strains enriched with TNT as a sole source of nitrogen under aerobic conditions, a gram-negative strain called TNT-8 and a gram-positive strain called TNT-32, carried out nitro-group reduction. In contrast, both a picric acid-utilizing Rhodococcus erythropolis strain, HL PM-1, and a 4-nitrotoluene-utilizing Mycobacterium sp. strain, HL 4-NT-1, possessed reductive enzyme systems, which catalyze ring hydrogenation, i.e., the addition of a hydride ion to the aromatic ring of TNT. The hydride-Meisenheimer complex thus formed (H-TNT) was further converted to a yellow metabolite, which by electrospray mass and nuclear magnetic resonance spectral analyses was established as the protonated dihydride-Meisenheimer complex of TNT (2H-TNT). Formation of hydride complexes could not be identified with the TNT-enriched strains TNT-8 and TNT-32, or with Pseudomonas sp. clone A (2NT), for which such a mechanism has been proposed. Correspondingly, reductive denitration of TNT did not occur.
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Affiliation(s)
- C Vorbeck
- Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik, and Institut für Mikrobiologie and Institut für Organische Chemie der Universität Stuttgart, D-70569 Stuttgart, Germany, and Armstrong Laboratory AL/EQC, Tyndall Air Force Base, Florida 32403-5233
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Bakhtiar R, Leung KH, Stearns RA, Hop CE. Evidence for a novel heme adduct generated by the in vitro reaction of 2,4,6-trinitrotoluene with human hemoglobin using electrospray ionization mass spectrometry. J Inorg Biochem 1997; 68:273-8. [PMID: 9397575 DOI: 10.1016/s0162-0134(97)00108-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The bioactivation of nitroaromatic compounds to highly reactive intermediates is responsible for the genotoxic and cytotoxic effects by reaction with DNA and proteins. Due to its continued use as a secondary explosive and its prevalence at contaminated sites, the mechanism of covalent binding of 2,4,6-trinitrotoluene (TNT), or its metabolites, to critical cellular proteins has been of interest. Herein, we report the in vitro reaction of TNT with human hemoglobin under anaerobic and reductive (using sodium hydrosulfite) conditions, yielding a novel adduct between a putative nitrosodinitrotoluene (MW = 211 Da) and the prosthetic heme group (iron protoporphyrin-IX or heme b). While the covalent modification of hemoglobin polypeptide chains by TNT has been established, to our knowledge, this is the first example of a heme-TNT related adduct. This finding could be of relevance in investigation of biotransformation of TNT in subjects exposed to TNT via skin exposure or inhalation.
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Affiliation(s)
- R Bakhtiar
- Department of Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey, USA.
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Väätänen AK, Ridanpää M, Norppa H, Kociba P. Spectrum of spontaneous and 2,4,6-trinitrotoluene (TNT)-induced mutations in Salmonella typhimurium strains with different nitroreductase and O-acetyltransferase activities. Mutat Res 1997; 379:185-90. [PMID: 9357547 DOI: 10.1016/s0027-5107(97)00136-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Spontaneous and 2,4,6-trinitrotoluene (TNT)-induced mutation spectra were determined at the hisD3052 allele of Salmonella typhimurium strains TA98, YG1021 (nitroreductase-overproducing) and YG1024 (O-acetyltransferase-overproducing). In TA98, 55% (11/20) of the spontaneous reversions and 95% (19/20) of reversions in TNT-treated plates were deletions of two bases at the same site (-2 hotspot deletions), whereas the respective figures were 65% (13/20) and 80% (16/20) in YG1021, and 75% (15/20) and 95% (19/20) in YG1024. Other mutations observed in the TNT treatment were complex frameshifts consisting of either a -2 hotspot deletion and a base substitution, or a +1 addition and base substitution at the stop codon. In addition, different kinds of deletions were recovered in the spontaneous spectra. The elevated enzymatic activities of strains, YG1021 and YG1024, resulting in enhanced mutagenicity of TNT, did not seem to have an effect on the spectrum of TNT-induced mutations. However, the YG strains, which also have a higher spontaneous revertant yield than the parental strain TA98, seemed to differ from TA98 in their spontaneous spectra. The increase consisted of revertants containing the -2 hotspot deletion, possibly indicating elevated activation of exogenous or endogenous premutagens by the higher enzyme activities of the YG strains.
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Affiliation(s)
- A K Väätänen
- Department of Industrial Hygiene and Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
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