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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] [Grants] [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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Yang H, Zhou M, Li H, Liu L, Zhou Y, Long X. Collective absorption of 2,4,6-trinitrotoluene into lipid membranes and its effects on bilayer properties. A computational study. RSC Adv 2019; 9:39046-39054. [PMID: 35540671 PMCID: PMC9075975 DOI: 10.1039/c9ra08408h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/22/2019] [Indexed: 11/21/2022] Open
Abstract
The widely used explosive, 2,4,6-trinitrotoluene (TNT), is a highly toxic chemical, which can cause hepatitis, cataracts, jaundice and so on, in humans. The interaction between TNT and biological membranes is crucial for understanding its toxic effects. Here, we mainly focused on molecular-level mechanisms for the collective adsorption of TNT into lipid membranes and the corresponding effects on bilayer properties by all-atom molecular dynamics simulations. We revealed that TNT can readily form an aggregate in the aqueous phase and quickly approach the surface of the membrane. At low concentrations of TNT (7 mol%), the aggregate is unstable and breaks up after several nanoseconds, and then the dispersed TNT molecules enter the membrane alone. At high concentrations (14 mol%), the aggregate is adsorbed as a whole and remains stable inside the membrane. After some of the TNT is absorbed by the membrane, the remaining TNT across the membrane would have greater permeability, i.e., the calculated permeability coefficient (P) is increased from 1.7 × 10-2 to 18.3 cm s-1. Correspondingly, a higher bioconcentration factor (BCF) was also observed. The increased level is more pronounced in the presence of TNT aggregates (i.e., high concentrations). This phenomenon is closely related to the strong interaction between TNT molecules. The results suggested that TNT molecules that have entered into the membrane can facilitate the membrane uptake, permeation and bioaccumulation of subsequent TNT molecules, exhibiting a synergistic effect. This work has a certain significance for understanding the toxicity of TNT.
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Affiliation(s)
- Hong Yang
- School of Material Science and Engineering, Tsinghua University Beijing 100084 China.,Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
| | - Mi Zhou
- Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
| | - Huarong Li
- Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
| | - Liu Liu
- Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
| | - Yang Zhou
- Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
| | - Xinping Long
- Institute of Chemical Materials, China Academy of Engineering and Physics Mianyang 621900 China
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Yang H, Li H, Liu L, Zhou Y, Long X. Molecular Simulation Studies on the Interactions of 2,4,6-Trinitrotoluene and Its Metabolites with Lipid Membranes. J Phys Chem B 2019; 123:6481-6491. [DOI: 10.1021/acs.jpcb.9b03033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Hong Yang
- School of Material Science and Engineering, Tsinghua University, Beijing 100084, China
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Huarong Li
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Liu Liu
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Yang Zhou
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
| | - Xinping Long
- Institute of Chemical Materials, China Academy of Engineering and Physics, Mianyang 621900, China
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Ushijima Y, Ohniwa RL, Morikawa K. Identification of nucleoid associated proteins (NAPs) under oxidative stress in Staphylococcus aureus. BMC Microbiol 2017; 17:207. [PMID: 28969590 PMCID: PMC5625760 DOI: 10.1186/s12866-017-1114-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 09/13/2017] [Indexed: 01/25/2023] Open
Abstract
Background Bacterial nucleoid consists of genome DNA, RNA, and hundreds of nucleoid-associated proteins (NAPs). Escherichia coli nucleoid is compacted towards the stationary phase, replacing most log-phase NAPs with the major stationary-phase nucleoid protein, Dps. In contrast, Staphylococcus aureus nucleoid sustains the fiber structures throughout the growth. Instead, the Dps homologue, MrgA, expresses under oxidative stress conditions to clump the nucleoid, but the composition of the clumped nucleoid was elusive. Results The staphylococcal nucleoid under oxidative stress was isolated by sucrose gradient centrifugation, and the proteins were analyzed by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). We identified 299 proteins in the nucleoid under oxidative stress, including 113 csNAPs (contaminant-subtracted NAPs). Comparison with the previously identified csNAPs in log- and stationary phase indicated that one fifth of the csNAPs under oxidative stress were the constitutive nucleoid components; importantly, several factors including HU, SarA, FabZ, and ribosomes were sustained under oxidative stress. Some factors (e.g. SA1663 and SA0092/SA0093) with unknown functions were included in the csNAPs list specifically under oxidative stress condition. Conclusion Nucleoid constitutively holds Hu, SarA, FabG, and ribosomal proteins even under the oxidative stress, reflecting the active functions of the clumped nucleoid, unlikely to the dormant E. coli nucleoid compacted in the stationary phase or starvation. Electronic supplementary material The online version of this article (10.1186/s12866-017-1114-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuri Ushijima
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. .,Present address: Department of Emerging Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, 852-8523, Japan.
| | - Ryosuke L Ohniwa
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan. .,Center for Biotechnology, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
| | - Kazuya Morikawa
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8575, Japan
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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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Johnston EJ, Rylott EL, Beynon E, Lorenz A, Chechik V, Bruce NC. Monodehydroascorbate reductase mediates TNT toxicity in plants. Science 2015; 349:1072-5. [DOI: 10.1126/science.aab3472] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Ziganshin AM, Ziganshina EE, Byrne J, Gerlach R, Struve E, Biktagirov T, Rodionov A, Kappler A. Fe(III) mineral reduction followed by partial dissolution and reactive oxygen species generation during 2,4,6-trinitrotoluene transformation by the aerobic yeast Yarrowia lipolytica. AMB Express 2015; 5:8. [PMID: 25852985 PMCID: PMC4314830 DOI: 10.1186/s13568-014-0094-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 12/29/2014] [Indexed: 11/23/2022] Open
Abstract
Understanding the factors that influence pollutant transformation in the presence of ferric (oxyhydr)oxides is crucial to the efficient application of different remediation strategies. In this study we determined the effect of goethite, hematite, magnetite and ferrihydrite on the transformation of 2,4,6-trinitrotoluene (TNT) by Yarrowia lipolytica AN-L15. The presence of ferric (oxyhydr)oxides led to a small decrease in the rate of TNT removal. In all cases, a significant release of NO2− from TNT and further NO2− oxidation to NO3− was observed. A fraction of the released NO2− was abiotically decomposed to NO and NO2, and then NO was likely oxidized abiotically to NO2 by O2. ESR analysis revealed the generation of superoxide in the culture medium; its further protonation at low pH resulted in the formation of hydroperoxyl radical. Presumably, a fraction of NO released during TNT degradation reacted with superoxide and formed peroxynitrite, which was further rearranged to NO3− at the acidic pH values observed in this study. A transformation and reduction of ferric (oxyhydr)oxides followed by partial dissolution (in the range of 7–86% of the initial Fe(III)) were observed in the presence of cells and TNT. Mössbauer spectroscopy showed some minor changes for goethite, magnetite and ferrihydrite samples during their incubation with Y. lipolytica and TNT. This study shows that i) reactive oxygen and nitrogen species generated during TNT transformation by Y. lipolytica participate in the abiotic conversion of TNT and ii) the presence of iron(III) minerals leads to a minor decrease in TNT transformation.
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Kumagai Y, Shimojo N. Possible mechanisms for induction of oxidative stress and suppression of systemic nitric oxide production caused by exposure to environmental chemicals. Environ Health Prev Med 2012; 7:141-50. [PMID: 21432269 DOI: 10.1007/bf02897942] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2002] [Accepted: 05/07/2002] [Indexed: 11/25/2022] Open
Abstract
The cytotoxic effects evoked by exposure to environmental chemicals having electrophilic properties are often attributable to covalent attachment to intracellular macromolecules through sulfhydryl groups or enzyme-mediated redox cycling, leading to the generation of reactive oxygen species (ROS). When huge amounts of ROS form they overwhelm antioxidant defenses resulting in the induction of oxidative stress. Nitric oxide (NO) which plays a crucial role in vascular tone, is formed by endothelial NO synthase (eNOS). Since a decrease in systemic NO production is implicated in the pathophysiological actions of vascular diseases, dysfunction of eNOS by environmental chemicals is associated with cardiopulmonary-related diseases and mortality. In this review, we introduce the mechanism-based toxicities (covalent attachment and redox cycling) of electrophiles. Therefore, this review will focus on the possible mechanisms for the induction of oxidative stress and impairment of NO production caused by environmental chemicals.
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Affiliation(s)
- Yoshito Kumagai
- Department of Environmental Medicine, Institute of Community Medicine, University of Tsukuba, 305-8575, Tsukuba, Ibaraki, Japan,
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Naderi M, Ghanei M, Shohrati M, Saburi A, Babaei M, Najafian B. Systemic complications of trinitrotoluene (TNT) in exposed workers. Cutan Ocul Toxicol 2012; 32:31-4. [PMID: 22994931 DOI: 10.3109/15569527.2012.699486] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION 2,4,6-trinitrotoluene (TNT) has been widely used as an explosive. TNT can induce some well-recognized toxic impacts comprising toxic hepatitis, aplastic anemia and cataract. The aim of study was evaluation of TNT exposed workers for systemic complication. METHODS In a cross-sectional study, we carried out Liver Function Test (LFT), complete blood count (CBC) and slit lamp biomicroscopy to compare the prevalence and severity of these 3 complications between 47 male TNT exposed workers (with at least one year continuous experience of TNT exposure) and 43 unexposed male hospital worker who hadn't had any previous contacts with TNT. We also performed Pulmonary Function Test (PFT) to assess the probable obstructive/restrictive abnormalities, caused by TNT. RESULTS Mean alkaline phosphatase (ALP) level of TNT exposed group was significantly higher than the unexposed group (p = 0.023) Forced Expiratory Volume in one second to Forced Vital Capacity (FEV1/FVC) ratios of both groups were in the range of restrictive pattern (82.03% and 81.42% for the exposed and unexposed group, respectively) with no meaningful difference. We didn't find out any specific TNT induced cataract and general cortical cataract (CC) and nuclear sclerotic cataract (NSC) prevalence was not significantly different. DISCUSSION we haven't found TNT as a chemical, causing toxic hepatitis or aplastic anemia; neither did we find it as a compound, responsible for a meaningful increase in cataract prevalence. However, due to the increased ALP serum levels and FEV1/FVC ratios among TNT workers, safety precautions are advised.
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Affiliation(s)
- Mostafa Naderi
- Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran, Islamic Republic of Iran
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Deng Y, Johnson DR, Guan X, Ang CY, Ai J, Perkins EJ. In vitro gene regulatory networks predict in vivo function of liver. BMC SYSTEMS BIOLOGY 2010; 4:153. [PMID: 21073692 PMCID: PMC2998496 DOI: 10.1186/1752-0509-4-153] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 11/12/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Evolution of toxicity testing is predicated upon using in vitro cell based systems to rapidly screen and predict how a chemical might cause toxicity to an organ in vivo. However, the degree to which we can extend in vitro results to in vivo activity and possible mechanisms of action remains to be fully addressed. RESULTS Here we use the nitroaromatic 2,4,6-trinitrotoluene (TNT) as a model chemical to compare and determine how we might extrapolate from in vitro data to in vivo effects. We found 341 transcripts differentially expressed in common among in vitro and in vivo assays in response to TNT. The major functional term corresponding to these transcripts was cell cycle. Similarly modulated common pathways were identified between in vitro and in vivo. Furthermore, we uncovered the conserved common transcriptional gene regulatory networks between in vitro and in vivo cellular liver systems that responded to TNT exposure, which mainly contain 2 subnetwork modules: PTTG1 and PIR centered networks. Interestingly, all 7 genes in the PTTG1 module were involved in cell cycle and downregulated by TNT both in vitro and in vivo. CONCLUSIONS The results of our investigation of TNT effects on gene expression in liver suggest that gene regulatory networks obtained from an in vitro system can predict in vivo function and mechanisms. Inhibiting PTTG1 and its targeted cell cycle related genes could be key mechanism for TNT induced liver toxicity.
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Affiliation(s)
- Youping Deng
- Rush University Medical Center, Chicago, IL 60612, USA.
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Gong P, Guan X, Inouye LS, Pirooznia M, Indest KJ, Athow RS, Deng Y, Perkins EJ. Toxicogenomic analysis provides new insights into molecular mechanisms of the sublethal toxicity of 2,4,6-trinitrotoluene in Eisenia fetida. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2007; 41:8195-8202. [PMID: 18186358 DOI: 10.1021/es0716352] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Xenobiotics such as explosives and pesticides released into the environment can have lethal and sublethal impacts on soil organisms such as earthworms with potential subsequent impacts at highertrophic levels. To better understand the molecular toxicological mechanisms of 2,4,6-trinitrotoluene (TNT), a commonly used explosive, in Eisenia fetida, earthworms were exposed to a gradient of TNT-spiked soils for 28 days and impacts on gene expression were examined using a 4032 cDNA microarray. Reproduction was increased at low doses of TNT, whereas high doses of TNT reduced juvenile production. On the basis of reproduction responses to TNT, four treatments, that is, control, 2, 10.6, and 38.7 mg/kg, were selected for gene expression studies in a balanced interwoven loop design microarray experiment in which the expression of 311 transcripts was significantly affected. Reverse-transcription quantitative polymerase chain reaction (RT-QPCR) data on 68 selected differentially and nondifferentially expressed transcripts showed a significant correlation with microarray results. The expression of genes involved in multiple biological processes was altered, including muscle contraction, neuronal signaling and growth, ubiquitinylation, fibrinolysis and coagulation, iron and calcium homeostasis, oxygen transport, and immunity. Chitinase activity assays confirmed down-regulation of chitinase genes as indicated by array and RT-QPCR data. An acute toxicity test provided evidence that dermal contact with TNT can cause bleeding, inflammation, and constriction, which may be explained by gene expression results. Sublethal doses of TNT affected the nervous system, caused blood disorders similar to methemoglobinemia, and weakened immunity in E. fetida.
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Affiliation(s)
- Ping Gong
- SpecPro Inc., 3909 Halls Ferry Road, Vicksburg, Mississippi 39180, 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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Sun Y, Sumi D, Kumagai Y. Serine 1179 phosphorylation of endothelial nitric oxide synthase caused by 2,4,6-trinitrotoluene through PI3K/Akt signaling in endothelial cells. Toxicol Appl Pharmacol 2006; 214:55-60. [PMID: 16516256 DOI: 10.1016/j.taap.2006.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 12/20/2005] [Accepted: 01/05/2006] [Indexed: 11/23/2022]
Abstract
Although 2,4,6-trinitrotoluene (TNT) has been found to uncouple nitric oxide synthase (NOS), thereby leading to reactive oxygen species (ROS), cellular response against TNT still remains unclear. Exposure of bovine aortic endothelial cells (BAECs) to TNT (100 microM) resulted in serine 1179 phosphorylation of endothelial NOS (eNOS). With specific inhibitors (wortmannin and LY294002), we found that PI3K/Akt signaling participated in the eNOS phosphorylation caused by TNT, whereas the ERK pathway did not. ROS were generated following exposure of BAECs to TNT. However, TNT-mediated phosphorylation of either eNOS or Akt was drastically blocked by NAC and PEG-CAT. Interestingly, pretreatment with apocynin, a specific inhibitor for NADPH oxidase, diminished the phosphorylation of eNOS and Akt. These results suggest that TNT affects NADPH oxidase, thereby generating hydrogen peroxide, which is capable of activating PI3K/Akt signaling associated with eNOS Ser 1179 phosphorylation.
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Affiliation(s)
- Yang Sun
- Doctoral Programs in Medical Sciences, Graduate School of Comprehensive Sciences, University of Tsukuba, Japan
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Kruse A, Hertel M, Hindsholm M, Viskum S. Trinitrotoluene (TNT)-induced cataract in Danish arms factory workers. ACTA ACUST UNITED AC 2005; 83:26-30. [PMID: 15715553 DOI: 10.1111/j.1600-0420.2005.00361.x] [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: 11/27/2022]
Abstract
PURPOSE To compare the prevalence of cataract in workers exposed to trinitrotoluene (TNT) to the prevalence in a group of unexposed workers, matched on age and sex, using Tiukina's description and grading of TNT-induced cataract. METHODS A total of 23 TNT-exposed and 44 unexposed workers underwent an eye examination performed by an ophthalmologist who did not know the exposure status of the subjects. All lens opacities matching Tiukina's description were classified as TNT cataract and graded on Tiukina's scale of stages 1-4. RESULTS Four cases of TNT-induced cataract were identified among the 23 TNT-exposed workers and none in the unexposed group (p < 0.01). CONCLUSION Exposure to TNT may cause a unique type of cataract, which a general ophthalmologist, using Tiukina's description and grading scale, will be able to distinguish from other cataracts.
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Affiliation(s)
- Anders Kruse
- Department of Ophthalmology, Aalborg Hospital, Hobrovej 18-22, PO Box 365, DK-9100 Aalborg, Denmark.
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Kumagai Y, Kikushima M, Nakai Y, Shimojo N, Kunimoto M. Neuronal nitric oxide synthase (NNOS) catalyzes one-electron reduction of 2,4,6-trinitrotoluene, resulting in decreased nitric oxide production and increased nNOS gene expression: implication for oxidative stress. Free Radic Biol Med 2004; 37:350-7. [PMID: 15223068 DOI: 10.1016/j.freeradbiomed.2004.04.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Revised: 03/22/2004] [Accepted: 04/22/2004] [Indexed: 11/23/2022]
Abstract
To determine the mechanism of 2,4,6-trinitrotoluene (TNT)-induced oxidative stress involving neuronal nitric oxide synthase (nNOS), we examined alterations in enzyme activity and gene expression of nNOS by TNT, with an enzyme preparation and rat cerebellum primary neuronal cells. TNT inhibited nitric oxide formation (IC(50) = 12.4 microM) as evaluated by citrulline formation in a 20,000 g cerebellar supernatant preparation. A kinetic study revealed that TNT was a competitive inhibitor with respect to NADPH and a noncompetitive inhibitor with respect to L-arginine. It was found that purified nNOS was capable of reducing TNT, with a specific activity of 3900 nmol of NADPH oxidized/mg/min, but this reaction required CaCl(2)/calmodulin (CaM). An electron spin resonance (ESR) study indicated that superoxide (O(2)(.-)) was generated during reduction of TNT by nNOS. Exposure of rat cerebellum primary neuronal cells to TNT (25 microM) caused an intracellular generation of H(2)O(2), accompanied by a significant increase in nNOS mRNA levels. These results indicate that CaM-dependent one-electron reduction of TNT is catalyzed by nNOS, leading to a reduction in NO formation and generation of H(2)O(2) derived from O(2)(.-). Thus, it is suggested that upregulation of nNOS may represent an acute adaptation to an increase in oxidative stress during exposure to TNT.
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Affiliation(s)
- Yoshito Kumagai
- Social and Environmental Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan.
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Fitzpatrick TB, Auweter S, Kitzing K, Clausen T, Amrhein N, Macheroux P. Structural and functional impairment of an Old Yellow Enzyme homologue upon affinity tag incorporation. Protein Expr Purif 2004; 36:280-91. [PMID: 15249051 DOI: 10.1016/j.pep.2004.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2004] [Indexed: 11/29/2022]
Abstract
Recently, it has been reported that the previously uncharacterized YqjM protein from Bacillus subtilis is a true homologue of the physiologically enigmatic yeast Old Yellow Enzyme (OYE). In this study, it was also demonstrated that YqjM is involved in the oxidative stress response of B. subtilis, thus highlighting a novel direction to pursue the role of the OYE family of proteins in the cell. As part of an attempt to pin down the exact physiological role of these enzymes, both a N-terminal glutathione S-transferase and a C-terminal histidine-tagged form of the protein were created to enable "pull-down" assays and identify interacting partners which could aid in the functional definition. However, here we report on a comparison of the biochemical properties of the tagged forms with the native/untagged YqjM, revealing critical differences in the catalytic activities and quaternary structure of the protein forms. UV-visible spectrophotometric features as well as steady state and individual half-reaction kinetic parameters show that the affinity tagged forms are severely impaired both in ligand binding and catalysis. Gel filtration and dynamic light scattering studies show that incorporation of a tag also has major effects on the quaternary structure of the protein by disrupting the native tetrameric conformation which may help to explain the observed differences. The study thus highlights important considerations for expression construct design when isolating members of the OYE family of proteins.
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Affiliation(s)
- Teresa B Fitzpatrick
- ETH-Zürich, Institut für Pflanzenwissenschaften, Universitätstr. 2, CH-8092 Zürich, Switzerland.
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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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Fitzpatrick TB, Amrhein N, Macheroux P. Characterization of YqjM, an Old Yellow Enzyme homolog from Bacillus subtilis involved in the oxidative stress response. J Biol Chem 2003; 278:19891-7. [PMID: 12660247 DOI: 10.1074/jbc.m211778200] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this paper, we demonstrate that a protein from Bacillus subtilis (YqjM) shares many characteristic biochemical properties with the homologous yeast Old Yellow Enzyme (OYE); the enzyme binds FMN tightly but noncovalently, preferentially uses NADPH as a source of reducing equivalents, and forms charge transfer complexes with phenolic compounds such as p-hydroxybenzaldehyde. Like yeast OYE and other members of the family, YqjM catalyzes the reduction of the double bond of an array of alpha,beta-unsaturated aldehydes and ketones including nitroester and nitroaromatic compounds. Although yeast OYE was the first member of this family to be discovered in 1933 and was the first flavoenzyme ever to be isolated, the physiological role of the family still remains obscure. The finding that alpha,beta-unsaturated compounds are substrates provoked speculation that the OYE family might be involved in reductive degradation of xenobiotics or lipid peroxidation products. Here, for the first time, we demonstrate on the protein level that whereas YqjM shows a basal level of expression in B. subtilis, the addition of the toxic xenobiotic, trinitrotoluene, leads to a rapid induction of the protein in vivo denoting a role in detoxification. Moreover, we show that YqjM is rapidly induced in response to oxidative stress as exerted by hydrogen peroxide, demonstrating a potential physiological role for this enigmatic class of proteins.
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Affiliation(s)
- Teresa B Fitzpatrick
- ETH-Zürich, Institut für Pflanzenwissenschaften, Universitätstrasse 2, Switzerland.
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Maruyama A, Kumagai Y, Morikawa K, Taguchi K, Hayashi H, Ohta T. Oxidative-stress-inducible qorA encodes an NADPH-dependent quinone oxidoreductase catalysing a one-electron reduction in Staphylococcus aureus. MICROBIOLOGY (READING, ENGLAND) 2003; 149:389-398. [PMID: 12624201 DOI: 10.1099/mic.0.25796-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This work characterized the putative quinone oxidoreductase gene (qorA) from Staphylococcus aureus. The deduced amino acid sequence indicated that the 333 aa protein contains an NAD(P)H-binding motif. A Northern blot analysis revealed that 2.6 kb and 1.4 kb signals were detected by using a qorA probe. Both the signals were enhanced under the presence of a redox-cycling agent, 9,10-phenanthrenequinone (PQ). It was also revealed that the expression of three genes, SA1988, SA1989 (qorA) and SA1990, was enhanced at the transcriptional level by PQ exposure. The results suggested that the 2.6 kb signal detected by the qorA probe was in two co-transcripts, i.e. SA1990-qorA and qorA-SA1988 were transcribed. Besides, primer extension analyses confirmed the enhancement of qorA and SA1990 transcripts. The GST (glutathione S-transferase)-tagged QorA protein was expressed in Escherichia coli and purified using a glutathione affinity column. In purification steps, a 36 kDa band co-purified with the GST-QorA, and it was detected even in the thrombin-cleaved fraction. N-terminal amino acid sequences for the 36 kDa protein revealed that it was an intact QorA. They showed that QorA formed a multimer under physiological conditions. The purified recombinant GST-QorA catalysed NADPH consumption in the presence of PQ as a substrate, but not NADH. To characterize the catalytic activity of QorA, superoxide anion that was generated through one-electron reduction of PQ and hydroquinone that was produced by two-electron reduction of PQ were measured. During reduction of PQ by GST-QorA, superoxide anion was generated, whereas a small amount of 9,10-dihydroxyphenanthrene (hydroquinone of PQ) was produced. These results suggest that the activity of QorA is similar to zeta-Crystallin, catalysing an NADPH-dependent one-electron reduction of quinone.
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Affiliation(s)
- Atsushi Maruyama
- Institute of Biological Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Yoshito Kumagai
- Institute of Community Medicine, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Kazuya Morikawa
- Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Keiko Taguchi
- Institute of Community Medicine, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Hideo Hayashi
- Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan
| | - Toshiko Ohta
- Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, 305-8577, Japan
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KUMAGAI Y, SHIMOJO N. Possible Mechanisms for Induction of Oxidative Stress and Suppression of Systemic Nitric Oxide Production Caused by Exposure to Environmental Chemicals. Environ Health Prev Med 2002. [DOI: 10.1265/ehpm.2002.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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