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1.
Plant Biotechnol J ; 15(5): 624-633, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27862819

RESUMO

The deposition of toxic munitions compounds, such as hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX), on soils around targets in live-fire training ranges is an important source of groundwater contamination. Plants take up RDX but do not significantly degrade it. Reported here is the transformation of two perennial grass species, switchgrass (Panicum virgatum) and creeping bentgrass (Agrostis stolonifera), with the genes for degradation of RDX. These species possess a number of agronomic traits making them well equipped for the uptake and removal of RDX from root zone leachates. Transformation vectors were constructed with xplA and xplB, which confer the ability to degrade RDX, and nfsI, which encodes a nitroreductase for the detoxification of the co-contaminating explosive 2, 4, 6-trinitrotoluene (TNT). The vectors were transformed into the grass species using Agrobacterium tumefaciens infection. All transformed grass lines showing high transgene expression levels removed significantly more RDX from hydroponic solutions and retained significantly less RDX in their leaf tissues than wild-type plants. Soil columns planted with the best-performing switchgrass line were able to prevent leaching of RDX through a 0.5-m root zone. These plants represent a promising plant biotechnology to sustainably remove RDX from training range soil, thus preventing contamination of groundwater.


Assuntos
Agrostis/genética , Biodegradação Ambiental , Panicum/genética , Plantas Geneticamente Modificadas , Triazinas/metabolismo , Agrostis/efeitos dos fármacos , Agrostis/metabolismo , Vetores Genéticos , Instalações Militares , NADH NADPH Oxirredutases/genética , Nitrorredutases/genética , Panicum/efeitos dos fármacos , Panicum/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Poluentes do Solo/metabolismo , Poluentes do Solo/farmacocinética , Triazinas/farmacocinética , Trinitrotolueno/farmacologia
2.
Biochim Biophys Acta ; 1850(9): 1877-83, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26026470

RESUMO

BACKGROUND: The genome of poplar (Populus trichocarpa) encodes 81 glutathione transferases (GSTs) annotated in eight distinct classes. The tau class is considered the most versatile in the biotransformation of xenobiotics and is composed of 58 GSTs. Two of the enzymes, GSTU16 and GSTU45, have particular interest since their expression is induced by exposure of poplar tissues to 2,4,6-trinitrotoluene (TNT) and could potentially be involved in the metabolism of this toxic environmental contaminant. RESULTS: DNA encoding these GSTs was synthesized and the proteins were heterologously expressed in Escherichia coli and the purified enzymes were characterized. MAJOR CONCLUSIONS: GSTU16 assayed with a number of conventional GST substrates showed the highest specific activity (60µmolmin⁻¹ mg⁻¹) with phenethyl isothiocyanate, 150-fold higher than that with CDNB. By contrast, GSTU45 showed CDNB as the most active substrate (3.3µmolmin⁻¹ mg⁻¹) whereas all of the 16 alternative substrates tested yielded significantly lower activities. Homology modeling suggested that the aromatic residues Phe10 and Tyr107 in the active site of GSTU16 are promoting the high activity with PEITC and other substrates with aromatic side-chains. Nonetheless, TNT was a poor substrate for GSTU16 as well as for GSTU45 with a specific activity of 0.05nmolmin⁻¹ mg⁻¹ for both enzymes. GENERAL SIGNIFICANCE: GSTU16 and GSTU45 do not play a major role in the degradation of TNT in poplar.


Assuntos
Glutationa Transferase/metabolismo , Trinitrotolueno/farmacologia , Sequência de Aminoácidos , Sítios de Ligação , Cristalização , Indução Enzimática/efeitos dos fármacos , Glutationa Transferase/química , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Especificidade por Substrato
3.
Chem Biol Interact ; 351: 109752, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34801537

RESUMO

2,4,6-trinitrotoluene (TNT) is a known source of reactive oxygen species (ROS), which cause oxidative stress in aquatic ecosystems. Carbonyl reductases (CRs) are one of several possible defense mechanisms induced against ROS products, especially those that result in the 'so-called' carbonyl stress. Daphnia magna, a freshwater organism living in stagnant freshwater bodies, expresses four copies of the CR gene (Dma_CR1, Dma_CR2, Dma_CR3 and Dma_CR4). In this study, induction of all four copies of Dma_CR by 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT), was investigated. Reverse transcription polymerase chain reaction (RT-PCR) analysis of treated daphnids revealed up-regulation of Dma_CR1 alone in response to TNT, but not 2-ADNT and 4-ADNT (which are key metabolites of TNT). This concentration- and time-dependent up-regulation in mRNA-expression was observed both in the presence and absence of light, in the same magnitude. Moreover, significant change in mRNA-expression could be observed 8 h after treatment with TNT. In the presence of TNT, the antioxidant N-acetylcysteine (NAc) could not reverse TNT-induced up-regulation of Dma_CR1 mRNA-expression. On the other hand, withdrawal of TNT from the culture medium caused a significant reduction in the TNT-induced mRNA-expression of Dma_CR1 within 24 h. These findings highlight the potential of Dma_CR1 as a biomarker for biomonitoring of TNT levels in freshwater bodies.


Assuntos
Carbonil Redutase (NADPH)/metabolismo , Daphnia/efeitos dos fármacos , Trinitrotolueno/farmacologia , Regulação para Cima/efeitos dos fármacos , Poluentes Químicos da Água/farmacologia , Compostos de Anilina/farmacologia , Animais , Biomarcadores/metabolismo , Carbonil Redutase (NADPH)/genética
4.
Funct Integr Genomics ; 10(4): 547-59, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20532806

RESUMO

The effect of recalcitrant soil and water pollutant 2,4,6-trinitrotoluen (TNT) on gene expression in Arabidopsis thaliana rosettes and roots was studied separately for the first time using microarrays. Seven-day exposure to TNT resulted in 170 up- and 122 down-regulated genes in the rosettes and 61 up- and 51 down-regulated genes in the roots (expression difference > 1.5-fold; p[t test] < 0.05). TNT concentration, 5 µg/ml, was selected according to the dose response analysis and study of TNT uptake from liquid media. Although many TNT induced genes fell into ontology groups annotated as response to biotic and abiotic stresses in rosettes and roots, only a small overlap of TNT effects on transcriptome was observed between rosettes and roots. The rosettes exhibited induction of several genes associated with toxin metabolism, such as UDP-glycosyltransferases and ATP-binding cassette (ABC) family transporters. On the other side, no genes known to be involved in TNT transformation were found to be up-regulated in the roots. The genes coding for enzymes involved in the cell wall modifications were abundantly up-regulated in roots. Microarray data indicated that after a relatively long incubation with TNT (7 days), metabolism of this xenobiotic proceeded mainly in aerial parts, while its translocation into cell walls still took place in the roots. Results obtained by microarray hybridization were validated by quantitative real-time reverse-transcription PCR. Nitrate reductase 1, several glycosyltransferases and ABC transporters, sucrose-proton symporter 2, thioredoxin-dependent peroxidase 2, and gamma-glutamyltransferase are discussed for their potential to enhance detoxification and toleration capability of plants to TNT.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Transferases/metabolismo , Trinitrotolueno , Arabidopsis/anatomia & histologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Substâncias Explosivas/farmacocinética , Substâncias Explosivas/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Inativação Metabólica , Proteínas de Membrana Transportadoras/genética , Análise em Microsséries , Estrutura Molecular , Transferases/genética , Trinitrotolueno/farmacocinética , Trinitrotolueno/farmacologia
5.
Chemosphere ; 73(5): 657-62, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18774158

RESUMO

Twelve Populus genes were identified from Arabidopsis thaliana sequences previously shown to be induced by exposure to 2,4,6-trinitrotoluene (TNT). Using the resources of the Poplar Genome Project and National Center for Biotechnology Information databases, Populus conserved domains were identified and used to design gene specific primers. RNA extracted from root tissues of TNT-exposed hydroponic poplar plants was used to quantify the expression of genes by reverse-transcriptase real-time polymerase chain reaction. Cyclophilin and 18S ribosomal DNA genes were used as internal standards. Exposure to TNT resulted in a significant increase of gene expression of two glutathione S-transferases (GST), peaking at levels of 25.0 +/- 13.1 and 10 +/- 0.7 fold the expression level of non-exposed plants after 24 h for each of the GST genes, respectively. This paper demonstrates the use of functional genomics information from the model plant species, Arabidopsis, to identify genes which may be important in detoxification of TNT in the model phytoremediation species, Populus trichocarpa.


Assuntos
Substâncias Explosivas/farmacologia , Regulação da Expressão Gênica de Plantas , Glutationa Transferase/genética , Populus/enzimologia , Trinitrotolueno/farmacologia , Biodegradação Ambiental , DNA de Plantas/metabolismo , Substâncias Explosivas/metabolismo , Genes de Plantas , Genoma de Planta , Glutationa Transferase/metabolismo , Populus/efeitos dos fármacos , Populus/metabolismo , Trinitrotolueno/metabolismo
6.
Appl Biochem Biotechnol ; 150(3): 337-44, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18563305

RESUMO

The goal of this work was to propose a possible mechanism for the butyrylcholinesterase activation by 2,4,6-trinitrotoluene (TNT), 3,3-dimethylbutyl-N-n-butylcarbamate (1), and 2-trimethylsilyl-ethyl-N-n-butylcarbamate (2). Kinetically, TNT, and compounds 1 and 2 were characterized as the nonessential activators of butyrylcholinesterase. TNT, and compounds 1 and 2 were hydrophobic compounds and were proposed to bind to the hydrophobic activator binding site, which was located outside the active site gorge of the enzyme. The conformational change from a normal active site gorge to a more accessible active site gorge of the enzyme was proposed after binding of TNT, and compounds 1 and 2 to the activator binding site of the enzyme. Therefore, TNT, and compounds 1 and 2 may act as the excess of butyrylcholine in the substrate activator for the butyrylcholinesterase catalyzed reactions.


Assuntos
Butirilcolinesterase/metabolismo , Carbamatos/farmacologia , Compostos de Trimetilsilil/farmacologia , Trinitrotolueno/farmacologia , Butirilcolinesterase/química , Domínio Catalítico/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Cinética , Estrutura Molecular , Conformação Proteica/efeitos dos fármacos
7.
Prikl Biokhim Mikrobiol ; 43(1): 59-64, 2007.
Artigo em Russo | MEDLINE | ID: mdl-17345860

RESUMO

2,4,6-Trinitrotoluene present in a culture of Escherichia coli K12, at a concentration of 200 mg/l, caused a decrease in the total cell population and the population of colony-forming units, increased permeability of the external lipoprotein envelope, and increased the refractive index of cells. The shape of some cells changed from rod-like to coccoid, and cell size decreased. The specific rate of glucose consumption and the content of NADH (NADPH) in cells decreased. The changes of these morphological and physiological features were reversible, tending to normalize after reduction of 2,4,6-trinitrotoluene concentration in the course of cultivation.


Assuntos
Escherichia coli K12/efeitos dos fármacos , Trinitrotolueno/farmacologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Escherichia coli K12/crescimento & desenvolvimento , Escherichia coli K12/metabolismo , Glucose/metabolismo , NAD/metabolismo , NADP/metabolismo , Trinitrotolueno/metabolismo
8.
Sci Rep ; 7(1): 8148, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28811603

RESUMO

2,4,6-trinitrotoluene (TNT) has been reported to cause numerous adverse effects. However, the detailed molecular mechanisms underlying TNT-induced liver toxicity need to be elucidated. In this study, we used HepG2 (p53wt) and Hep3B (p53null) cell lines to investigate the cytotoxic effects of TNT. At first, we found that TNT significantly decreased cell viability and induced DNA damage. Thereafter, through transcriptomic analysis, we observed that the diverse biological functions affected included mitochondrial dysfunction and endoplasmic reticulum (ER) stress. Mitochondrial dysfunction was evidenced by the loss of mitochondrial membrane potential, increased expression of cleaved-caspase-9&-3 and increased caspase-3/7 activity, indicating that apoptosis had occurred. In addition, the expressions of some ER stress-related proteins had increased. Next, we investigated the role of reactive oxygen species (ROS) in TNT-induced cellular toxicity. The levels of DNA damage, mitochondrial dysfunction, ER stress and apoptosis were alleviated when the cells were pretreated with N-acetyl-cysteine (NAC). These results indicated that TNT caused the ROS dependent apoptosis via ER stress and mitochondrial dysfunction. Finally, the cells transfected with CHOP siRNA significantly reversed the TNT-induced apoptosis, which indicated that ER stress led to apoptosis. Overall, we examined TNT-induced apoptosis via ROS dependent mitochondrial dysfunction and ER stress in HepG2 and Hep3B cells.


Assuntos
Apoptose/efeitos dos fármacos , Estresse do Retículo Endoplasmático , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Trinitrotolueno/farmacologia , Apoptose/genética , Caspase 3/metabolismo , Caspase 7/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA , Estresse do Retículo Endoplasmático/genética , Perfilação da Expressão Gênica , Humanos , Mitocôndrias/genética , Transdução de Sinais , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Transcriptoma
9.
Cell Biochem Biophys ; 72(2): 417-28, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25561288

RESUMO

Detection of 2,4,6-trinitrotoluene (TNT) has been extensively studied since it is a common explosive filling for landmines, posing significant threats to the environment and human safety. The rapid advances in synthetic biology give new hope to detect such toxic and hazardous compounds in a more sensitive and safe way. Biosensor construction anticipates finding sensing elements able to detect TNT. As TNT can induce some physiological responses in E. coli, it may be useful to define the sensing elements from E. coli to detect TNT. An E. coli MG1655 genomic promoter library containing nearly 5,400 elements was constructed. Five elements, yadG, yqgC, aspC, recE, and topA, displayed high sensing specificity to TNT and its indicator compounds 1,3-DNB and 2,4-DNT. Based on this, a whole cell biosensor was constructed using E. coli, in which green fluorescent protein was positioned downstream of the five sensing elements via genetic fusion. The threshold value, detection time, EC200 value, and other aspects of five sensing elements were determined and the minimum responding concentration to TNT was 4.75 mg/L. According to the synthetic biology, the five sensing elements enriched the reservoir of TNT-sensing elements, and provided a more applicable toolkit to be applied in genetic routes and live systems of biosensors in future.


Assuntos
Técnicas Biossensoriais/métodos , Proteínas de Escherichia coli/genética , Trinitrotolueno/análise , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Trinitrotolueno/farmacologia
10.
Br J Pharmacol ; 95(1): 67-76, 1988 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3146397

RESUMO

1. A number of amiloride analogues were used to test the proposal that Na+/Ca2+ exchange may play a role in the secretion of endothelium-derived relaxing factor (EDRF). The analogues used were those substituted on either the 5-amino group or the terminal guanidino nitrogen atom. The former block both Na+/Ca2+ and Na+/H+ exchange whilst the latter block the Na+ channel and the Na+/Ca2+ exchange. 2. Both series of compounds caused relaxation in isolated rings of dog coronary artery (EC50 values, 1-10 microM) presumably due to release of EDRF since removal of endothelium greatly attenuated the response. 3. Amiloride (1-100 microM) had little effect on either endothelium-intact or denuded arteries. 4. The guanidino substituted analogues also appeared to block selectively the relaxation response to acetylcholine in the coronary artery, independently of their EDRF-releasing activity. 5. It is proposed that endothelial cells have an active Na+/Ca2+ exchange operating in the forward mode to extrude Ca2+. This mechanism may be important in the control of EDRF release.


Assuntos
Amilorida/análogos & derivados , Fatores Biológicos/metabolismo , Endotélio Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Amilorida/farmacologia , Animais , Calcimicina/farmacologia , Cálcio/metabolismo , Vasos Coronários/metabolismo , Cães , Endotélio Vascular/fisiologia , Feminino , Íleo/efeitos dos fármacos , Íleo/metabolismo , Técnicas In Vitro , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Óxido Nítrico , Sódio/metabolismo , Trinitrotolueno/farmacologia
11.
Acta Biochim Pol ; 47(4): 941-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11996117

RESUMO

Enterobacter cloacae NAD(P)H:nitroreductase catalyzes the reduction of a series of nitroaromatic compounds with steady-state bimolecular rate constants (kcat/Km) ranging from 10(4) M(-1) s(-1) to 10(7) M(-1) s(-1), and oxidizing 2 moles NADH per mole mononitrocompound. Oxidation of excess NADH by polynitrobenzenes including explosives 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenyl-N-methylnitramine (tetryl), has been observed as a slower secondary process, accompanied by O2 consumption. This type of 'redox cycling' was not related to reactions of nitroaromatic anion-radicals, but was caused by the autoxidation of relatively stable reaction products. The logs kcat/Km of all the compounds examined exhibited parabolic dependence on their enthalpies of single-electron- or two-electron (hydride) reduction, obtained by quantum mechanical calculations. This type of quantitative structure-activity relationships shows that the reactivity of nitroaromatics towards E. cloacae nitroreductase depends mainly on their hydride accepting properties, but not on their particular structure, and does not exclude the possibility of multistep hydride transfer.


Assuntos
Enterobacter cloacae/enzimologia , Nitrato Redutases/química , Nitrato Redutases/metabolismo , Elétrons , Cinética , Modelos Químicos , Nitrato Redutase (NAD(P)H) , Oxigênio/metabolismo , Relação Estrutura-Atividade , Termodinâmica , Trinitrotolueno/farmacologia
12.
Mutat Res ; 262(3): 167-9, 1991 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2002814

RESUMO

The urine mutagenicity of rats exposed to 2,4,6-trinitrotoluene (TNT) by i.p. injection was studied in the Salmonella assay using indicator strains with various levels of 'classical' nitroreductase or acetyl-CoA:N-hydroxylarylamine O-acetyltransferase activity. The strains used were the conventional Salmonella typhimurium TA98, nitroreductase-deficient TA98NR and -overproducing YG1021, and O-acetyltransferase-deficient TA98/1,8-DNP6 and -overproducing YG1024. TA98, YG1021 and YG1024 clearly detected the increase of direct urine mutagenicity. A slight increase of mutagenicity was also detected with metabolic activation in YG1021 and YG1024. High levels of both nitroreductase and O-acetyltransferase significantly increased the sensitivity of the indicator strain to the mutagenicity of urine caused by TNT exposure, while the nitroreductase- or O-acetyltransferase-deficient strains gave negative responses.


Assuntos
Acetiltransferases/urina , Testes de Mutagenicidade , Nitrorredutases/urina , Ratos Endogâmicos , Trinitrotolueno/farmacologia , Animais , Masculino , Ratos
13.
J Pharm Pharmacol ; 55(3): 359-65, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12724042

RESUMO

The possible involvement of the endothelium in the vasodilator action of eugenol was investigated in the mesenteric vascular bed (MVB) of the rat. Bolus injections of eugenol (0.2, 2 and 20 micromol) and acetylcholine (ACh; 10, 30 and 100 pmol) induced dose-dependent vasodilator responses in noradrenaline-precontracted beds that were partially inhibited by pretreatment of the MVB with deoxycholate (1 mg mL(-1)) to remove the endothelium (approximately 14% and approximately 30% of the control response remaining at the lowest doses of ACh and eugenol, respectively). The vasodilator effect of glyceryl trinitrate (1 micromol) was unaltered by deoxycholate. In the presence of either N(omega)-nitro-L-arginine methyl ester (300 microM) or tetraethylammonium (1 mM)the response to ACh was partially reduced, whereas eugenol-induced vasodilation was unaffected. Similarly the vasodilator effect of eugenol was not inhibited by indometacin (3 microM). Under calcium-free conditions the vasoconstrictor response elicited by bolus injections of noradrenaline (10 nmol) was dose-dependently and completely inhibited by eugenol (0.1-1 mM). Additionally, the pressor effects of bolus injections of calcium chloride in potassium-depolarized MVBs were greatly reduced in the presence of eugenol (0.1 mM), with a maximal reduction of approximately 71% of the control response. Our data showed that eugenol induced dose-dependent, reversible vasodilator responses in the rat MVB, that were partially dependent on the endothelium, although apparently independent of nitric oxide, endothelium-derived hyperpolarizing factor or prostacyclin. Furthermore, an endothelium-independent intracellular site of action seemed likely to participate in its smooth muscle relaxant properties.


Assuntos
Endotélio Vascular/fisiologia , Eugenol/farmacologia , Circulação Esplâncnica/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Cálcio/fisiologia , Ácido Desoxicólico/farmacologia , Inibidores Enzimáticos/farmacologia , Indometacina/farmacologia , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo III , Norepinefrina/farmacologia , Perfusão , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Ratos Wistar , Tetraetilamônio/farmacologia , Trinitrotolueno/farmacologia , Vasoconstritores/farmacologia , Vasodilatadores/farmacologia
14.
Chemosphere ; 44(8): 1703-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11534902

RESUMO

A number of in vitro and in vivo studies have determined that binary and complex mixtures may interact to produce a toxicity that could not be predicted based on the individual chemicals. The present study was conducted with a binary mixture of model compounds to investigate possible interactions affecting their mutagenicity. The compounds included Benzo[a]pyrene (BAP), a polycyclic aromatic hydrocarbon that is an indirect-acting mutagen of great environmental concern, and 2,4,6-Trinitrotoluene (TNT), a nitro-aromatic compound that is a direct-acting mutagen frequently found as a soil contaminant at munitions sites. This study indicated that a binary mixture of BAP and TNT failed to induce the positive mutagenic response in Salmonella typhimurium strain TA98 characteristic of either compound alone. Spectrofluorometric analysis of BAP, and kinetic analyses of 3HBAP uptake in the presence or absence of TNT using TA98 cells that were treated or untreated with activated rat liver microsomes were performed. In cells preloaded with BAP, cellular BAP fluorescence was rapidly suppressed in the presence of TNT. Mass spectroscopy of BAP and TNT mixtures revealed a number of products, believed to be the result of complexation and nitration, that may account for the antagonistic action of TNT on BAP-induced mutagenicity in TA98 cells. Further, kinetic studies indicated that TNT inhibited the incorporation of BAP into cells.


Assuntos
Benzo(a)pireno/farmacocinética , Carcinógenos Ambientais/farmacocinética , Trinitrotolueno/farmacologia , Animais , Benzo(a)pireno/administração & dosagem , Carcinógenos Ambientais/administração & dosagem , Interações Medicamentosas , Cinética , Microssomos Hepáticos , Ratos , Salmonella typhimurium , Espectrometria de Fluorescência , Trinitrotolueno/química
15.
Biomed Environ Sci ; 2(1): 72-7, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2556157

RESUMO

Trinitrotoluene (TNT) increased the formation of adrenochrome from adrenaline and the formation of formaldehyde from methanol in rat liver mitochondria and microsomes in vitro as well as in monkey liver mitochondria and microsomes in vivo. The effects were more prominent at higher TNT concentrations. These findings indicate that TNT enhances the production of superoxide radicals (O2) and hydrogen peroxide (H2O2). The production of O2 was more prominent in systems containing added TNT than in those containing added benzyl viologen. H2O2 production by mitochondria was more pronounced in the liver than in other organs, but its production by microsomes was more pronounced in the brain than in other organs. The results suggest that TNT undergoes cycling reduction which produces oxidative stress.


Assuntos
Peróxido de Hidrogênio/metabolismo , Fígado/efeitos dos fármacos , Superóxidos/metabolismo , Trinitrotolueno/farmacologia , Animais , Encéfalo/metabolismo , Técnicas In Vitro , Rim/metabolismo , Fígado/metabolismo , Macaca mulatta , Masculino , Microssomos/metabolismo , Mitocôndrias/metabolismo , Ratos , Ratos Endogâmicos , Testículo/metabolismo
16.
Z Naturforsch C J Biosci ; 56(11-12): 1157-63, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11837672

RESUMO

We have examined the structure-activity relationships in methemoglobin (MetHb) formation by high explosives 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenyl-N-nitramine (tetryl) and 2,4,6-trinitrophenyl-N-nitraminoethylnitrate (pentryl), and a number of model nitrobenzenes. In lysed human erythrocytes the rate constants of oxyhemoglobin (OxyHb) oxidation increased with an increase in single-electron reduction potential (E(1)7) or with a decrease of the enthalpies of single-electron reduction of nitroaromatics. Tetryl and pentryl oxidized OxyHb almost 3 times faster than TNT. Although the initial rates of MetHb formation in intact erythrocytes by tetryl, pentryl, and TNT matched their order of reactivity in the oxidation of OxyHb in lysed erythrocytes, TNT was a more efficient MetHb forming agent than tetryl and pentryl during a 24-h incubation. The decreased efficiency of tetryl and pentryl was attributed to their reaction with intraerythrocyte reduced glutathione (GSH) producing 2,4,6-trinitrophenyl-Sglutathione, which acted as a less efficient OxyHb oxidizing agent.


Assuntos
Eritrócitos/metabolismo , Metemoglobina/metabolismo , Oxiemoglobinas/metabolismo , Trinitrotolueno/farmacologia , Dinitrobenzenos/farmacologia , Eritrócitos/efeitos dos fármacos , Humanos , Cinética , Oxirredução , Relação Estrutura-Atividade
19.
Microb Biotechnol ; 2(2): 287-94, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21261922

RESUMO

Pseudomonas putida KT2440 grows in M9 minimal medium with glucose in the presence of 2,4,6-trinitrotoluene (TNT) at a similar rate than in the absence of TNT, although global transcriptional analysis using DNA microarrays revealed that TNT exerts some stress. Response to TNT stress is regulated at the transcriptional level, as significant changes in the level of expression of 65 genes were observed. Of these genes, 39 appeared upregulated, and 26 were downregulated. The identity of upregulated genes suggests that P. putida uses two kinds of strategies to overcome TNT toxicity: (i) induction of genes encoding nitroreductases and detoxification-related enzymes (pnrA, xenD, acpD) and (ii) induction of multidrug efflux pump genes (mexEF/oprN) to reduce intracellular TNT concentrations. Mutants of 13 up- and 7 downregulated genes were analysed with regards to TNT toxicity revealing the role of the MexE/MexF/OprN pump and a putative isoquinoline 1-oxidoreductase in tolerance to TNT. The ORF PP1232 whose transcriptional level did not change in response to TNT affected growth in the presence of nitroaromatic compounds and it was found in a screening of 4000 randomly generated mutants.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Pseudomonas putida/efeitos dos fármacos , Pseudomonas putida/genética , Trinitrotolueno/farmacologia , Xenobióticos/farmacologia , Proteínas de Bactérias/genética , Pseudomonas putida/enzimologia , Pseudomonas putida/metabolismo , Transcrição Gênica/efeitos dos fármacos
20.
J Ind Microbiol Biotechnol ; 35(4): 225-36, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18228070

RESUMO

To gain insight into the impact of 2,4,6-trinitrotoluene (TNT) on soil microbial communities, we characterized the bacterial community of several TNT-contaminated soils from two sites with different histories of contamination and concentrations of TNT. The amount of extracted DNA, the total cell counts and the number of CFU were lower in the TNT-contaminated soils. Analysis of soil bacterial diversity by DGGE showed a predominance of Pseudomonadaceae and Xanthomonadaceae in the TNT-contaminated soils, as well as the presence of Caulobacteraceae. CFU from TNT-contaminated soils were identified as Pseudomonadaceae, and, to a lesser extent, Caulobacteraceae. Finally, a pristine soil was spiked with different concentrations of TNT and the soil microcosms were incubated for 4 months. The amount of extracted DNA decreased in the microcosms with a high TNT concentration [1.4 and 28.5 g TNT/kg (dry wt) of soil] over the incubation period. After 7 days of incubation of these soil microcosms, there was already a clear shift of their original flora towards a community dominated by Pseudomonadaceae, Xanthomonadaceae, Comamonadaceae and Caulobacteraceae. These results indicate that TNT affects soil bacterial diversity by selecting a narrow range of bacterial species that belong mostly to Pseudomonadaceae and Xanthomonadaceae.


Assuntos
Bactérias/efeitos dos fármacos , Microbiologia do Solo , Poluentes do Solo/farmacologia , Trinitrotolueno/farmacologia , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Biodegradação Ambiental , Impressões Digitais de DNA , DNA Bacteriano/análise , DNA Bacteriano/genética , DNA Ribossômico/análise , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo/análise , Poluentes do Solo/metabolismo , Células-Tronco , Trinitrotolueno/metabolismo
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