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1.
Mar Pollut Bull ; 156: 111275, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32510414

RESUMO

Environmental contamination by organophosphate flame retardants (OPFRs) and plasticizers are environmental concerns. In this study, 18 OPFRs were analyzed in sediment and bivalves collected from 50 locations along the Korean coast to assess occurrence, geographical distribution, contamination source, and bioaccumulation potential. Tris(1-chloro-2-propanyl) phosphate (TCPP) and tris(2-ethylhexyl) phosphate (TEHP) were highly detected (>80%) OPFRs in sediment and bivalves. Total concentrations of OPFRs and plasticizers in sediment and bivalves ranged from 2.18 to 347 ng/g dry weight and from 6.12 to 206 ng/g dry weight, respectively, which were within the ranges reported for previous studies. Sedimentary organic carbon was a primary factor governing the OPFR distribution. Concentrations of OPFRs and plasticizers in sediments from harbor zones were significantly higher than non-harbor zones, indicating that shipping activity is a contamination source of OPFRs and plasticizers in coastal environments. Biota-sediment accumulation factors <1 for several OPFRs indicated limited potential for bioaccumulation.


Assuntos
Bivalves , Retardadores de Chama , Animais , Bioacumulação , Organofosfatos , Compostos Organofosforados , Plastificantes , República da Coreia
2.
Environ Pollut ; 264: 114788, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32559856

RESUMO

Tris (1,3-dichloro-2-propyl) phosphate (TDCPP) is a type halogenated organophosphate flame retardants (OPFRs), which has been identified as contaminants of emerging concern (CECs). The use and production of OPFRs began to increase gradually when brominated flame retardants (BFRs) were banned. Halogenated OPFRs, especially TDCPP have been considered to lead to mutagenicity and carcinogenesis and major concerns have been raised regarding their toxicity. In this study, the toxicity effects and mechanisms of TDCPP were summarized and ecological risk assessment was made regarding its potential impact on freshwater organisms. TDCPP has been widely detected in ecosystems throughout the world, with observed toxicity effects on both humans and freshwater organisms. Inhalation of the dust was found to be the main exposure for humans. TDCPP could be metabolized in the human body, and medium stability was achieved in human body with the main metabolite BDCPP. Aside from mutagenicity and carcinogenesis, TDCPP was also found to have the potential for endocrine disruption and impairing the human reproductive system. Furthermore, this study reviewed the results of previous toxicity experiments, including acute toxicity, growth and development toxicity, neurotoxicity, and hepatotoxicity in freshwater organisms. Risk assessment was made using the safety threshold method by comparing the toxicity data with the exposure data in freshwater. HC5 (hazardous concentration for 5% of organisms) derived based on traditional endpoints of acute toxicity LC50 (median lethal concentration) or EC50 (concentration for 50% of maximal effect) was 877 µg/L. This value was much higher than the exposure concentration levels in the surface water with EXD90 (exposure data with cumulative probability 90%) of 65.22 ng/L. However, based on the growth and development toxicity data, the derived HC5 was 33.33 ng/L and the calculated MOS (margin of safety) was below 1. Therefore, the results validated the fact that the ecological risk of TDCPP could not be neglected for its growth and development toxicity.


Assuntos
Retardadores de Chama , Fosfatos , Ecossistema , Água Doce , Humanos , Organofosfatos , Compostos Organofosforados , Medição de Risco
3.
Crit Rev Oncol Hematol ; 151: 102990, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32485428

RESUMO

EGFR exon 20 alterations are rare events seen mainly in non-small cell lung cancer (NSCLC). They include EGFR T790 and C797S mutations (associated with secondary resistance to classic EGFR tyrosine kinase inhibitors (TKIs)), and EGFR exon 20 in-frame insertions (associated with resistance to first- and second-generation EGFR TKIs). In silico modeling of structural changes in aberrant proteins has informed selection of compounds with potential clinical activity: poziotinib (whose smaller size permits access to the restricted kinase pocket created by EGFR and ERBB2 exon 20 insertions); cetuximab (an antibody that attenuates dimerization caused by EGFR exon 20 insertions), and TAK-788 (another EGFR/ERBB2 TKI). Other alterations, such as EGFR T790 M, are responsive to osimertinib, while the EGFR C797S alteration seen in osimertinib resistance demonstrates preclinical sensitivity to combined brigatinib and cetuximab. These observations indicate that clinical resistance can be overcome by utilizing advanced genomic interrogation coupled with computer modeling.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Resistencia a Medicamentos Antineoplásicos , Receptores ErbB/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Cetuximab/uso terapêutico , Receptores ErbB/química , Éxons , Humanos , Mutação , Compostos Organofosforados/uso terapêutico , Inibidores de Proteínas Quinases , Pirimidinas/uso terapêutico
4.
Chem Biol Interact ; 326: 109111, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32413347

RESUMO

Human scalp hair is a biological matrix that can trap chemical vapours from explosives (TNT), drugs (THC) and chemical weapons (yperite). The external contamination of human's hair following exposure to organophosphorus (OP) nerve agent was simulated by model compounds: triethyl phosphate (TEP) and diisopropyl fluorophosphate (DFP). In this work were exposed strands of hair to vapours of TEP and DFP (3 and 7 ppmv) to model sorption kinetics. Sorption isotherms were also investigated at several contamination levels (80-3000 mg min.m-3). OP nerve agent simulants were extracted from hair by soaking in DCM. Raw extracts were analysed in GC-MS/MS to quantify each simulant content in hair. Results were fitted by applying isotherm or kinetic equations. The best model was found to be bimodal first-order, suggesting the co-existence of two different mechanisms of sorption. The best equation to describe OP vapours incorporation on hair was Freundlich model. Thus hair can be used as a passive sensor able to trap chemical G-agents and can also offer valuable information regarding both individual contamination and proof of exposure to chemical weapons.


Assuntos
Substâncias para a Guerra Química/química , Cabelo/química , Couro Cabeludo/química , Humanos , Isoflurofato/química , Gás de Mostarda/química , Agentes Neurotóxicos/química , Organofosfatos/química , Compostos Organofosforados/química
5.
Chemosphere ; 256: 127066, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32434091

RESUMO

Tri(1,3-dichloropropyl) phosphate (TDCPP) potentially damages the thyroid system in humans and animals. However, knowledge of its toxic effects and underlying mechanisms is limited. The present study was conducted to determine the thyroid hormone-disrupting effects of TDCPP and its major metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP) in rat pituitary cell lines (GH3). TDCPP and BDCPP, that mimic the thyroid hormone (TH), promoted GH3 cell proliferation and modulated the progression of the cell cycle at 20 and 200 µmol/L, respectively. Similar to T3, TDCPP and BDCPP also significantly upregulated c-fos and downregulated Tshß gene expression. Although the binding affinity of these chemicals for thyroid receptor ß (TRß) was not measured, significant competition between these chemicals to bind to the membrane thyroid hormone receptor (integrin αvß3) was found, suggesting that TDCPP and BDCPP were strongly bound to integrin αvß3. Results from a molecular docking analysis provided further evidence of strong binding affinities of TDCPP and BDCPP for integrin αvß3, and the ligand binding site of Arg-Gly-Asp (RGD) was identified. Real-time PCR also supported the supposition that, after binding to integrin αvß3, TDCPP and BDCPP may induce the activation of the extracellular signal-regulated protein kinase (ERK1/2) signal transduction pathway. Taken together, our data suggest that TDCPP and BDCPP have the ability to mimic THs and that the underlying mechanism might be associated with their interactions with integrin αvß3 and the activation of the ERK1/2 pathway, providing new insight into the mechanism of TDCPP- and BDCPP-induced cytotoxicity.


Assuntos
Organofosfatos/toxicidade , Hormônios Tireóideos/metabolismo , Testes de Toxicidade , Animais , Proliferação de Células/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Integrina alfaVbeta3/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína Quinase 3 Ativada por Mitógeno , Simulação de Acoplamento Molecular , Oligopeptídeos , Organofosfatos/metabolismo , Compostos Organofosforados , Ratos , Transdução de Sinais , Glândula Tireoide/efeitos dos fármacos
6.
Chemosphere ; 256: 126895, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32460157

RESUMO

The appearance of an increased amount of organophosphate flame retardant (OPFRs) in natural water is related the treated effluents from wastewater treatment plants (WWTPs) and thus understanding the OPFRs concentration and reduction variation in WWTPs would provide valuable insight into OPFR management and reduction. In this study, we have analyzed OPFRs (10 kinds: tris(chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP), tris(1,3-dichloropropyl) phosphate (TDCP), tris(phenyl) phosphate (TPhP), tris(2-ethylhexyl) phosphate (TEHP), diphenylcresylphosphate (DCP), tris(methylphenyl) phosphate (TCP), tris(2-butoxyethyl) phosphate (TBEP), 2-ethylhexyl diphenyl phosphate (EHDP), and tris(butyl) phosphate (TBP)) in both water and sludge samples collected from different phases of a WWTP upgrading. The results show that TCPP and TCEP were mainly present in the aqueous phase, whereas TEHP dominated in the solid phase. The overall OPFR reduction efficiencies were above 40% through whole treatment processes by all the phases. More OPFRs reduction efficiency in primary sedimentation tanks was higher mainly because of bigger tank volume. The anaerobic zone in all cases could decrease OPFRs by over 13%. The removal of OPFRs in the oxic zone highly varied under the influence of the aeration pipe, water temperature, and aeration amount. Compared with chlorinated OPFRs, aryl and alkyl OPFRs were easier to reduce and less affected by the upgrading. Because OPFRs have been widely used in plastic materials such as pipes, WWTP upgrading - which usually requires more aeration and addition of reagents and instruments and the aim of which is normally to reduce more COD, N and P -- has introduced more OPFRs into the water within the WWTP.


Assuntos
Retardadores de Chama/análise , Compostos Organofosforados/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Organofosfatos , Esgotos
7.
Eur J Protistol ; 74: 125705, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32464434

RESUMO

The ciliate Paramecium tetraurelia has four arginine kinase genes (AK1, AK2, AK3, and AK4). Of these genes, only AK3 has a signal sequence for farnesylation, a post-translational modification that enables anchoring of the modified enzyme to the ciliary membrane. To confirm this modification, AK3 was synthesized using a cell-free protein synthesis system and the peptide masses were analyzed using peptide mass fingerprinting (PMF). The PMF analysis indicated that the C-terminal peptide of AK3 is farnesylated. Thus, AK3 can be farnesylated under physiologically appropriate conditions. To determine the subcellular localization of P. tetraurelia AK3, Western blot analysis was performed using an AK3 polyclonal antibody for the proteins extracted from intact cells and ciliary fractions. When extraction was performed using Triton X-100, AK3 was detected the ciliary fraction. This result suggested that the ciliary fraction contains AK3. In addition, we investigated the role of P. tetraurelia AKs in ciliary movement using the feeding RNA interference method. The swimming velocity of AK1- and AK3-silenced cells was significantly reduced to half the value of that control cells. In summary, P. tetraurelia AK3 is likely to be located in the ciliary membrane and influences swimming velocity, presumably through the phosphoarginine shuttle system present in cilia.


Assuntos
Arginina Quinase/metabolismo , Arginina/análogos & derivados , Paramecium tetraurellia/enzimologia , Arginina/metabolismo , Cílios/enzimologia , Compostos Organofosforados/metabolismo
8.
Environ Sci Pollut Res Int ; 27(20): 25715-25726, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32356062

RESUMO

Exposure to organophosphate (OP) pesticides in children may increase oxidative stress, resulting in the development of chronic diseases. This study aims to compare urinary OP metabolites and oxidative stress between children in agricultural and urban communities. The study also investigated the factors associated with urinary OP metabolites among children. Urine samples were collected from children for measuring levels of OP metabolites, glutathione (GSH), and malondialdehyde (MDA). The remarkable findings were that total dialkylphosphate (DAP) levels detected among children in this agricultural community were significantly higher than those from the urban community (P = 0.001). Multiple linear regression showed that total diethylphosphate (DEP) levels among children in the agricultural community were negatively associated with distances from children's residence to the agricultural fields (ß ± SE. = - 1.535 ± 0.334, 95%CI = - 2.202, - 0.863) and positively associated with playing on farms (ß ± SE. = 0.720 ± 0.342, 95%CI = 0.036, 1.405). In addition, total dimethylphosphate (DMP) levels were positively associated with children working on farms (ß ± SE. = 0.619 ± 0.264, 95%CI = 0.091, 1.147). Importantly, GSH levels among children in the agricultural community were significantly lower than those in the urban community (P < 0.001), but MDA levels did not differ. These results therefore suggest that children can be exposed to OPs both outdoors and indoors. Our results also provide supporting evidence that OP exposure can cause oxidative stress in children. As oxidative stress contributes to several chronic diseases, a good proposed strategy for the future would include measurement of oxidative stress biomarkers among children exposed to OPs as an early warning of chronic diseases.


Assuntos
Inseticidas/análise , Praguicidas , Agricultura , Criança , Exposição Ambiental/análise , Humanos , Organofosfatos , Compostos Organofosforados , Estresse Oxidativo
9.
Sci Total Environ ; 724: 138307, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32272412

RESUMO

As alternatives of brominated flame retardants, organophosphate flame retardants (OPFRs) can be detected in multiple marine environmental media. Tris(1-chloro-2-propyl)phosphate (TCPP) was one of the most frequently and abundantly detected OPFRs in the Bohai Sea. Exposure to TCPP has been shown to induce abnormal behavior in zebrafish as well as neurotoxicity in Caenorhabditis elegans. However, there is a lack of mechanism investigations on the toxic effects of TCPP at molecular levels. In this work, proteomics and metabolomics were integrated to analyze the proteome and metabolome responses in rockfish Sebastes schlegeli treated with TCPP (10 and 100 nM) for 15 days. A total of 143 proteins and 8 metabolites were significantly altered in rockfish following TCPP treatments. The responsive proteins and metabolites were predominantly involved in neurotransmission, neurodevelopment, signal transduction, cellular transport, cholesterol metabolism, bile acid synthesis, and detoxification. Furthermore, a hypothesized network of proteins, metabolites, and pathways in rockfish was summarized based on the combination of proteomic and metabolomic results, showing some key molecular events in response to TCPP. Overall, the present study unraveled the molecular responses at protein and metabolite levels, which provided a better understanding of toxicological effects and mechanisms of TCPP in marine teleost.


Assuntos
Retardadores de Chama , Proteômica , Animais , Metabolômica , Organofosfatos , Compostos Organofosforados , Perciformes , Fosfatos , Porfirinas
10.
Environ Pollut ; 263(Pt A): 114525, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32289612

RESUMO

Organophosphate flame retardants (OPFRs) are widespread in the aquatic environment, but the effects of these chemicals on reproductive toxicity are far from clear. In this study, sperm quality in adult male Chinese rare minnows after exposure to tris-(2-butoxyethyl) phosphate (TBOEP), tris-(1,3-dichloro-2-propyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP) was investigated. No obvious change in sperm concentration and vitality was observed after treatments, whereas significant changes in sperm velocity and morphology were found following all treatments (P < 0.05). Moreover, OPFR exposure significantly increased the apoptosis ratios in testis cells. Analysis of the transcriptomic data revealed that Na+/K+ ATPase (NKA) related genes were significantly downregulated, and the NKA enzyme activities after all treatments were significantly inhibited (P < 0.05). However, no obvious change in hormone levels in the groups exposed to TBOEP and TDCIPP was observed. These findings indicate that the OPFR-induced reduction of sperm quality might be due to the effects of OPFRs on NKA enzyme instead of changes in hormone levels.


Assuntos
Cyprinidae , Retardadores de Chama , Animais , Masculino , Organofosfatos , Compostos Organofosforados , Espermatozoides
11.
Sci Total Environ ; 726: 138526, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32304943

RESUMO

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a widely used organophosphorus flame retardant, has been frequently detected in the environment including indoor dust. Long-term exposure to TDCPP-containing dust may adversely affect human skin, however, little is known about its potential cytotoxicity. In this study, human skin keratinocytes (HaCaT) were employed to study TDCPP-induced cytotoxicity and associated mechanisms. The effects of TDCPP on cell morphology, viability, apoptosis, and cycle, and the mRNA levels of apoptosis (Bcl-2, Bax and Caspase-3) and cell cycle (cyclin D1, CDK2, CDK4 and CDK6) regulatory genes were investigated. The results showed that TDCPP caused a concentration-dependent decrease in cell viability after exposing to TDCPP ≥100 µg/mL for 48 h, with a median lethal concentration of 163 µg/mL (LC50). In addition, TDCPP induced cell apoptosis and arrested cell cycle in the G0/G1 phase at 16 and 160 µg/mL by enhancing Bax and Caspase-3 expression besides inhibiting cyclin D1, CDK2, CDK6 and Bcl-2 expression. Our results showed that TDCPP-induced toxicity in HaCaT cells was probably through cell apoptosis and cell cycle arrest. This study provides information on the toxicity of TDCPP to human skin cells, which may help to reduce its toxicity to human skin.


Assuntos
Retardadores de Chama , Apoptose , Poeira , Humanos , Queratinócitos/química , Organofosfatos , Compostos Organofosforados/análise
12.
Sci Total Environ ; 727: 138486, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-32330713

RESUMO

Graphene oxide (GO), a novel two-dimension carbon nanomaterial, has showed tremendous potential for utilization in intelligent manufacturing and environmental protection. In parallel, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is widely distributed in the water environment and represents a great threat to ecosystem health. However, the related knowledge remained absent regarding the impact of GO on the biological risks of TDCIPP. Herein, GO significantly reduced the mortality and malformation rates of zebrafish induced by TDCIPP maximumly by 28.6% and 41.8%, respectively. Decreased mitochondrial respiratory chain (MRC) enzyme and ATP activity induced by TDCIPP were mitigated by GO. Integrating proteomics and metabolomics revealed TDCIPP obviously induced the downregulation of the proteins and metabolites involved in the cytoskeleton, mitochondrial function, carbohydrate and amino acid metabolism, and the TCA cycle, but the alterations were attenuated by GO. GO primarily promoted MRC activity, carbohydrate metabolism, and fatty acid ß-oxidation, thus activating the energy metabolism of zebrafish and leading to antagonistic effects on the developmental toxicity of TDCIPP. These results provide a novel view on the co-exposure of GO with other pollutants and promote the reconsideration of the environmental risks of GO.


Assuntos
Retardadores de Chama , Peixe-Zebra , Animais , Ecossistema , Transporte de Elétrons , Grafite , Organofosfatos , Compostos Organofosforados
13.
Bull Environ Contam Toxicol ; 104(6): 792-798, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32335690

RESUMO

In this study, the photodegradation of organophosphorus (OPs) pesticides in the honey medium was evaluated under sunlight irradiation. Some of the 22 samples collected at different sites contained OPs pesticides (Methyl parathion, Coumaphos and Fenitrothion) with an average of 8 ng/g. Moreover, three samples were found with pesticide residue levels exceeding the maximum residue limits (MRL ≥ 50 ng/g) imposed by the standard water (WHO). Gas chromatography (GC) combined with a tritium electron capture detector system was used for the analysis of OPs pesticides in honey. Total degradation of the Methyl parathion was obtained in less than 60 min of irradiation. Moreover, the elimination of the other OPs found in the samples was also effective with a rate of 85% for Coumaphos and Fenitrothion after 50 min of sunlight irradiation. The kinetics of the photodegradation reaction of all OPs pesticides studied followed a pseudo-first order model.


Assuntos
Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Mel/análise , Compostos Organofosforados/análise , Praguicidas/análise , Luz Solar , Argélia , Cromatografia Gasosa , Mel/efeitos da radiação , Mel/normas , Cinética , Resíduos de Praguicidas/análise , Fotólise
14.
Food Chem ; 320: 126683, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32229401

RESUMO

Here, we demonstrate use of acetylcholinesterase (AChE)-responsive polyoxometalate (POM)/surfactant supramolecular spheres to build a liquid crystal (LC)-based sensing platform for detection of organophosphorus pesticides. The self-assembled spheres are composed of hybrid materials of a POM, sodium dodecatungstophosphate (PW12), and a surfactant, myristoylcholine (Myr). It displays dark appearance when the aqueous solution is in contact with LCs supported on the octadecyltrichlorosilane-treated glass deposited with the supramolecular spheres, suggesting perpendicular orientation of LCs at the aqueous/LC interface. In contrast, LCs show bright appearance when the surface-deposited supramolecular spheres are enzymatically hydrolyzed by AChE, corresponding to planar orientation of LCs at the aqueous/LC interface. Detection of organophosphates are successfully achieved as they are potent inhibitors of AChE. The detection limit of the sensing platform reached 0.9 ng/mL for dimethoate. This method can avoid disturbance of external interference with excellent specificity and sensitivity, which makes it very promise in detection of organophosphorus pesticides.


Assuntos
Acetilcolinesterase/metabolismo , Análise de Alimentos/métodos , Cristais Líquidos/química , Praguicidas/análise , Análise de Alimentos/instrumentação , Hidrólise , Lagos/análise , Limite de Detecção , Compostos Organofosforados/análise , Silanos/química , Tensoativos/química , Compostos de Tungstênio/química , Água/química , Poluentes Químicos da Água/análise
15.
Food Chem ; 321: 126678, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32240916

RESUMO

A simple analytical method was developed and validated, as per SANTE 2017 guidelines, for simultaneous determination of 10 organophosphorus residues in curry leaf using gas chromatography with flame photometric detection, and confirmed using gas chromatography-mass spectrometry. Samples were extracted with ethyl acetate and cleaned up with primary secondary amine and graphitized carbon black. Average recoveries were in the range 80-108% with the RSD of less than 8%. The effects of different household cleaning techniques to reduce the concentration of pesticide residues in curry leaf were evaluated and found to remove 2-65% of residues. The method was applied to analyse sample to fresh curry leaf samples, and analysis of potential health risks estimated the residues did not pose a direct hazard. This method could be useful for routine analysis of organophosphorus residue for monitoring purposes.


Assuntos
Descontaminação , Compostos Organofosforados/análise , Rutaceae/química , Cromatografia Gasosa-Espectrometria de Massas , Resíduos de Praguicidas/análise , Fotometria/métodos , Folhas de Planta/química , Medição de Risco
16.
PLoS One ; 15(4): e0231981, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348360

RESUMO

An acetylcholinesterase biosensor modified with graphene and transition metal carbides was prepared to detect organophosphorus pesticides. Cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy were used to characterize the electrochemical catalysis of the biosensor: acetylcholinesterase/chitosan-transition metal carbides/graphene/glassy carbon electrode. With the joint modification of graphene and transition metal carbides, the biosensor has a good performance in detecting dichlorvos with a linear relationship from 11.31 µM to 22.6 nM and the limit of detection was 14.45 nM. Under the premise of parameter optimization, the biosensor showed a good catalytic performance for acetylcholine. Compared to the biosensors without modification, it expressed a better catalytic performance due to the excellent electrical properties, biocompatibility and high specific surface area of graphene, transition metal carbides. Finally, the biosensor exhibits good stability, which can be stored at room temperature for one month without significant performance degradation, and has practical potential for sample testing.


Assuntos
Acetilcolinesterase/metabolismo , Técnicas Biossensoriais/métodos , Grafite/química , Nanocompostos/química , Compostos Organofosforados/análise , Praguicidas/análise , Técnicas Eletroquímicas , Eletrodos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Limite de Detecção , Reprodutibilidade dos Testes , Titânio/química , Elementos de Transição/química
17.
Chemosphere ; 252: 126549, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32229357

RESUMO

Fenamiphos is a neurotoxic organophosphorus pesticide used widely to control pests of crops. Fenamiphos and its toxic oxidation products have been detected in surface and groundwaters. A novel enzyme capable of hydrolysing P-O-C bond of fenamiphos is purified from Microbacterium esteraromaticum MM1 total cellular protein using a combination of methods. The purified fenamiphos hydrolysing enzyme (FHE) was identified as enolase (phosphopyruvate hydratase), a housekeeping enzyme with molecular mass and pI value of 45 kDa and 4.5, respectively. The optimum pH and temperature for the activity of the FHE are 7 and 25 °C, respectively. We studied the influence of metal ions and inhibitors on the enzyme activity. The enzyme was strongly activated by Mg2+ whereas Hg2+ and phenylmethyl sulfonyl fluoride (PMSF) inhibited the enzyme. The kinetic parameters, Km and Vmax for fenamiphos hydrolysis were estimated to be 584.15 ± 16.22 µM and 6.46 ± 0.13 µM min-1, respectively. The FHE was functionally active against its original substrate (2-phosphoglycerate) with Km value of 5.82 ± 1.42 µM and Vmax of 4.2 ± 0.1 µM min-1. This enzyme has great potential for its application in the detoxification of fenamiphos and its warfare homologs. To our knowledge, this is the first report on the purification of fenamiphos hydrolysing enzyme.


Assuntos
Actinobacteria/enzimologia , Compostos Organofosforados/metabolismo , Actinomycetales , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Oxirredução , Praguicidas
18.
J Chromatogr A ; 1622: 461127, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32331778

RESUMO

Gas chromatographic columns based on ionic liquids (ILs) are very promising since the selectivity of these columns can be tuned by both the cation and the anion chemical nature. In this paper, efficiencies of capillary columns based on four phosphonium ionic liquids were studied. The performance of seven columns containing the cation trihexyl(tetradecyl)phosphonium and the anions bromide, chloride, and bis(trifluoromethylsulfonyl)imide was evaluated by measuring the solute band broadening as a function of gas velocities at three temperatures. Hence, classical height equivalent to a theoretical plate (H) against gas velocity (u) plots corresponding to those columns were generated and the data were fitted to the Golay-Guiochon equation with the aim of seeking the optimum conditions to be operated each of them. Band broadening at practical gas velocities is mainly due to poor mass transfer properties of solutes in the (viscous) liquid phases, which limits the achieved efficiencies. These H/u plots proved to be necessary to characterize the column quality at a given temperature, to interpret the band broadening phenomena and thus, to establish the lower temperature limits and the expected plate counts at that temperature.


Assuntos
Cromatografia Gasosa/métodos , Líquidos Iônicos/química , Compostos Organofosforados/química , Ânions , Cátions , Difusão , Dióxido de Silício/química , Temperatura
19.
Chemosphere ; 253: 126698, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302901

RESUMO

Organophosphates insecticides (OPs) are one of the major environmental pollutants and their interaction with human serum albumin (HSA) has been shown to have significant effects on their bioavailability which is related to toxicokinetics and toxicodynamics in human body. In this research, solid-phase microextraction methods were developed to analyse the free concentrations of three OPs (chlorpyrifos, parathion-methyl and malathion) in buffered HSA solution and that provide a useful method for the determination of binding affinity constants (Ka), binding forces and binding location. Polydimethylsiloxane fibers were selected for analysing the free concentrations of OPs, with an external calibration approach. Good linearities conducted in PBS solution were observed in the range of 0.0025-1.7 µmol L-1 (R2 = 0.9975) for chlorpyrifos, 1.0-27 µmol L-1 (R2 = 0.9974) for parathion-methyl, and 0.5-70 µmol L-1 (R2 = 0.9973)for malathion, respectively. The LODs for instrument response were 1 ng, 5 ng and 10 ng for chlorpyrifos, parathion-methyl and malathion, respectively. The Ka values for chlorpyrifos, parathion-methyl and malathion showed that they were positively correlated with hydrophobicity and negatively correlated with temperature. The OP binding sites on HSA were confirmed by site marker competition test and further proven by computational approaches. The recognition region of parathion-methyl was situated within residues 199-292 in subdomain IIA. Malathion bonded to residues 404-558 in subdomain IIIA. The mode of action between HSA-parathion-methyl and HSA-malathion is found to involve mainly by H-bonds, π-π stacking and hydrophobic effects. These results clearly demonstrate the noncovalent binding of OPs with HSA and provide new insight into solid-phase microextraction, thermodynamics and computational approaches.


Assuntos
Inseticidas/toxicidade , Compostos Organofosforados/toxicidade , Clorpirifos , Dimetilpolisiloxanos , Humanos , Inseticidas/química , Inseticidas/metabolismo , Malation/análise , Metil Paration , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Microextração em Fase Sólida , Temperatura , Termodinâmica
20.
PLoS One ; 15(4): e0231652, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298342

RESUMO

Lemna species have been used in the food, feed, and pharmaceutical industries, as they are inexpensive sources of proteins, starches, and fatty acids. In this study, we treated L. paucicostata with different concentrations (0.05, 0.1, 0.2, 0.5, or 1 mM) of ethephon. The total dry weight decreased in all ethephon-treated groups compared to the control group. We also investigated the alteration of metabolic profiles induced by ethephon treatment by using gas chromatography-mass spectrometry. This analysis identified 48 metabolites, and the relative levels of most of alcohols, amino acids, fatty acids, and phenols increased by the ethephon treatment, whereas levels of organic acids and sugars decreased. Among these, the highest production of γ-aminobutyric acid (GABA, 5.041 ± 1.373 mg/L) and ferulic acid (0.640 ± 0.071 mg/L) was observed in the 0.5 mM and the 0.2 mM ethephon treatment groups, respectively. These results could be useful for large-scale culture of L. paucicostata with enhanced GABA and ferulic acid content for utilization in the food, feed, cosmetic, and pharmaceutical industries.


Assuntos
Araceae/crescimento & desenvolvimento , Ácidos Cumáricos/metabolismo , Compostos Organofosforados/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Ácido gama-Aminobutírico/metabolismo , Araceae/metabolismo , Metaboloma
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