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Chemosphere Apr 2023Methyl parathion (MP) is a typical organophosphorus pesticide that is widely used worldwide, and hydrolysis, oxidation and reduction are the main abiotic degradation...
Methyl parathion (MP) is a typical organophosphorus pesticide that is widely used worldwide, and hydrolysis, oxidation and reduction are the main abiotic degradation processes. Manganese dioxide (MnO) and organic acid can participate in various geochemical processes of pollutants, a reaction system was constructed to degrade MP using δ-MnO and oxalic acid. The δ-MnO/oxalic acid reaction system could efficiently degrade MP, and the removal rate of MP (20 μM) reached 67.83% within 30 h under the optimized conditions (pH 5, [δ-MnO] = 2 mM, [oxalic acid] = 100 mM). MP was hydrolyzed by substitution reactions of S@P and S@C, and reduced by conversion of the nitro groups (-NO) in MP and its hydrolysates to amino groups (-NH). The primary active substance produced in the reaction system was the complexes dominated by Mn(III)-oxalic acid. This study provides a scientific basis for the degradation of organophosphorus pesticides using MnO and an organic acid. The results have important theoretical significance and application value for pollution control and remediation of organophosphorus pesticides.
Topics: Methyl Parathion; Oxides; Organophosphorus Compounds; Pesticides; Oxalic Acid; Manganese Compounds; Oxidation-Reduction; Kinetics
PubMed: 36739984
DOI: 10.1016/j.chemosphere.2023.138054 -
Environmental Toxicology Jun 2013Methyl parathion (C₈H₁₀NO₅PS) and parathion (C₁₀H14 NO₅PS) are both organophosphate insecticides (OPI) widely used for household and agricultural...
Methyl parathion (C₈H₁₀NO₅PS) and parathion (C₁₀H14 NO₅PS) are both organophosphate insecticides (OPI) widely used for household and agricultural applications. They are known for their ability to irreversibly inhibit acetylcholinesterase which often leads to a profound effect on the nervous system of exposed organisms. Many recently published studies have indicated that human exposure to OPI may be associated with neurologic, hematopoietic, cardiovascular, and reproductive adverse effects. Studies have also linked OPI exposure to a number of degenerative diseases including Parkinson's, Alzheimer's, and amyotrophic lateral sclerosis. Also, oxidative stress (OS) has been reported as a possible mechanism of OPI toxicity in humans. Hence, the aim of the present investigation was to use human liver carcinoma (HepG₂) cells as a test model to evaluate the role of OS in methyl parathion- and parathion-induced toxicity. To achieve this goal, we performed the MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay for cell viability, lipid peroxidation assay for malondialdehyde (MDA) production, and Comet assay for DNA damage, respectively. Results from MTT assay indicated that methyl parathion and parathion gradually reduce the viability of HepG₂ cells in a dose-dependent manner, showing 48 h-LD₅₀ values of 26.20 mM and 23.58 mM, respectively. Lipid peroxidation assay resulted in a significant increase (P < 0.05) of MDA level in methyl parathion- and parathion-treated HepG₂ cells compared with controls, suggesting that OS plays a key role in OPI-induced toxicity. Comet assay indicated a significant increase in genotoxicity at higher concentrations of OPI exposure. Overall, we found that methyl-parathion is slightly less toxic than parathion to HepG₂ cells. The cytotoxic effect of these OPI was found to be associated, at least in part, with oxidative cell/tissue damage.
Topics: Cell Survival; Comet Assay; DNA Damage; Hep G2 Cells; Humans; Insecticides; Lethal Dose 50; Lipid Peroxidation; Malondialdehyde; Methyl Parathion; Oxidative Stress; Parathion
PubMed: 21544925
DOI: 10.1002/tox.20725 -
Chemistry (Weinheim An Der Bergstrasse,... Jul 2019Herein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [Ru (bpy) (CN) ] (Cu I) (bpy=2,2'-bipyridine), is described. This complex integrates a...
Herein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [Ru (bpy) (CN) ] (Cu I) (bpy=2,2'-bipyridine), is described. This complex integrates a task-specific catalyst (Cu -catalyst) and a signaling unit ([Ru (bpy) (CN) ]) to specifically hydrolyze methyl parathion, a highly toxic organophosphate (OP) pesticide. The bimetallic complex catalyzed the hydrolysis of the phosphate ester to generate o,o-dimethyl thiophosphate (DTP) anion and 4-nitrophenolate. Intrinsically, 4-nitrophenolate absorbed UV/Vis light at λ =400 nm, creating the first level of the chemosensing signal. DTP interacted with the original complex to displace the chromophore, [Ru (bpy) (CN) ], which was monitored by spectrofluorometry; this was classified as the second level of chemosensing signal. By integrating both spectroscopic and spectrofluorometric signals with a simple AND logic gate, only methyl parathion was able to provide a positive response. Other aromatic and aliphatic OP pesticides (diazinon, fenthion, meviphos, terbufos, and phosalone) and 4-nitrophenyl acetate provided negative responses. Furthermore, owing to the metal-catalyzed hydrolysis of methyl parathion, the CCA system led to the detoxification of the pesticide. The CCA system also demonstrated its catalytic chemosensing properties in the detection of methyl parathion in real samples, including tap water, river water, and underground water.
Topics: Catalysis; Colorimetry; Coordination Complexes; Copper; Fluorometry; Hydrolysis; Methyl Parathion; Models, Molecular; Nitrophenols; Organometallic Compounds; Organothiophosphates; Pesticides; Spectrophotometry, Ultraviolet; Water; Water Pollutants, Chemical
PubMed: 31017704
DOI: 10.1002/chem.201901656 -
Toxicology Letters Feb 2004Methyl parathion (MP; O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This...
Methyl parathion (MP; O,O-dimethyl O-p-nitrophenyl phosphorothioate) is an organophosphorous compound still largely used in agriculture and fish hatcheries. This pesticide is not quite selective and is potentially toxic for both vertebrates and invertebrates. Its mechanism of acute toxicity is the inhibition of the enzyme acetylcholinesterase in nervous tissue. Binding of pesticides to plasma proteins is one of many factors that influence their distribution and elimination. The free concentration available for toxic action can be effectively reduced for pesticides with high binding to plasma proteins, although the affinity of pesticides to plasma proteins is often lower than for the enzyme targets. Several different transport proteins exist in blood plasma, but albumin only is able to bind a wide diversity of xenobiotics reversibly with high affinity. It was already known that parathion (ethyl parathion) exhibits a high affinity to human and bovine serum albumins. We studied interactions of methyl parathion with these albumins by using fluorescence quenching techniques. We selectively excited the fluorescence of tryptophan residues with a 290 nm wavelength light, and observed quenching by titrating human and bovine serum albumin solutions with methyl parathion. Stern-Volmer graphs were plotted and quenching constants were estimated. Our results pointed to the formation of complexes of methyl parathion with albumins. Association constants at 25 degrees C were 3.07 x 10(4) (1.2 x 10(3))M(-1) for human serum albumin, and 1.96 x 10(4) (+/- 4.5 x 10(2))M(-1) for bovine serum albumin. At 37 degrees C, they were 1.08 x 10(4) (+/- 2.0 x 10(2))M(-1) for human serum albumin, and 8.16 x 10(3) (+/- 1.9 x 10(2))M(-1) for bovine serum albumin. Results also suggest that the primary binding site for methyl parathion on albumin is close to tryptophan residues 214 of human serum albumin and 212 of bovine serum albumin.
Topics: Animals; Binding, Competitive; Cattle; Cholinesterase Inhibitors; Fluorescence; Humans; In Vitro Techniques; Methyl Parathion; Protein Binding; Serum Albumin, Bovine; Spectrometry, Fluorescence; Tryptophan
PubMed: 14700528
DOI: 10.1016/j.toxlet.2003.10.014 -
Archives Internationales de... 1990Male rats administered with a single i.p. dose of 5 mg/kg methyl parathion, showed the toxic signs of hypercholinergic (anticholinesterase) activity with maximal...
Male rats administered with a single i.p. dose of 5 mg/kg methyl parathion, showed the toxic signs of hypercholinergic (anticholinesterase) activity with maximal severity, including muscle fasciculations and convulsions within 15 to 30 min, persisting for about 2 hr. The time course of acetylcholinesterase activity in discrete brain regions (cortex, stem, striatum and hippocampus), heart and hemidiaphragm, indicated its maximal depression during 30 to 60 min after administration of methyl parathion. At this time, a marked reduction in carboxylesterase activity was also evident both in neuronal and nonneuronal tissues, suggesting a tremendous binding to nonacetylcholinesterase serine sites. Pretreatment with memantine hydrochloride (18 mg/kg, i.p.) 30 min, and atropine sulfate (16 mg/kg, i.p.) 15 min before methyl parathion administration, completely prevented the expected toxic signs and significantly (P less than 0.01) attenuated the induced inhibition of acetylcholinesterase. When given therapeutically, this combined treatment completely reversed the clinical evidence of methyl parathion toxicity within 10 to 15 min and markedly reduced the acetylcholinesterase inactivation. These results suggest that memantine may counteract the acute methyl parathion toxicity by (a) protection of acetylcholinesterase from inhibition, (b) rapid reactivation of inhibited acetylcholinesterase and (c) rapid bioelimination of methyl parathion, in addition to cholinolytic effects of atropine sulfate.
Topics: Acetylcholinesterase; Animals; Atropine; Brain; Brain Chemistry; Carboxylic Ester Hydrolases; Male; Memantine; Methyl Parathion; Myocardium; Rats; Rats, Inbred Strains; Respiratory Muscles; Seizures
PubMed: 2241428
DOI: No ID Found -
Letters in Applied Microbiology Jan 2014Methyl parathion hydrolase (MPH) can degrade a wide range of organophosphorus compounds, but its efficiency in hydrolysing chlorpyrifos, one of the most popular...
UNLABELLED
Methyl parathion hydrolase (MPH) can degrade a wide range of organophosphorus compounds, but its efficiency in hydrolysing chlorpyrifos, one of the most popular pesticides applied for crop protection, is much lower than that in hydrolysing the preferred substrate methyl parathion. In this study, random mutagenesis was adopted to improve MPH to enhance its efficiency in hydrolysing the poorly hydrolysed substrate chlorpyrifos. Rapid screening of the improved MPH variants was carried out using Bacillus subtilis WB800 secretory expression system to investigate the distribution of improved MPH variants based on the size of clear haloes as a result of chlorpyrifos hydrolysis. Four improved MPH variants were isolated, and one variant K3, in particular, showed a 5-fold increase in kcat value for chlorpyrifos hydrolysis. Furthermore, most of the MPH variants obtained in this study possessed enhanced thermostability and pH stability. The approaches adopted in this study could be extended to create other MPH variants with increased activity for hydrolysing other poorly hydrolysed substrates.
SIGNIFICANCE AND IMPACT OF THE STUDY
Chlorpyrifos is one of the toxic organophosphorus compounds (OP compounds) widely used for insecticides control. Water, soil and foodstuff have been contaminated seriously by chlorpyrifos in some areas. It is urgent to find effective methods to remove its contamination. This work contributes to improve methyl parathion hydrolase (MPH) to enhance its efficiency in hydrolysing the poorly hydrolysed substrate chlorpyrifos. Our study brings new insights for enzymatic strategy for the decontamination of toxic OP compounds.
Topics: Amino Acid Substitution; Chlorpyrifos; Enzyme Stability; Hydrogen-Ion Concentration; Hydrolysis; Insecticides; Kinetics; Methyl Parathion; Molecular Sequence Data; Mutagenesis; Phosphoric Monoester Hydrolases; Protein Conformation; Protein Engineering; Protein Multimerization
PubMed: 24010722
DOI: 10.1111/lam.12155 -
Environmental Health Perspectives Dec 2002The Illinois Department of Public Health participated in the Chicago, Illinois, area methyl parathion (MP) response with several other federal, state, and local...
The Illinois Department of Public Health participated in the Chicago, Illinois, area methyl parathion (MP) response with several other federal, state, and local government agencies beginning in April 1997. This response was initiated on evidence that hundreds of homes in the Chicago area were illegally treated for cockroaches with MP over a period of several years. Through applicator receipt books and information reported by property owners and tenants, 968 homes were identified as having been treated with MP. Upon implementation of a response plan developed by the Methyl Parathion Health Sciences Steering Committee, environmental sampling and urine monitoring were provided for eligible households. Environmental sampling was conducted in 903 homes, with MP detected above levels of concern in 596 residences. Residents of these homes were offered urine sampling to determine the extent of exposure to MP. Urine samples were collected and analyzed for p-nitrophenol in 1,913 individuals. Implementation of the protocol resulted in 550 residents being relocated during the remediation of 100 households.
Topics: Adolescent; Adult; Aged; Chicago; Child; Child, Preschool; Environment; Environmental Exposure; Environmental Monitoring; Female; Humans; Infant; Infant, Newborn; Insect Control; Insecticides; Interinstitutional Relations; Local Government; Male; Methyl Parathion; Middle Aged; Nitrophenols; Pregnancy; Program Evaluation; State Government; Urban Population
PubMed: 12634143
DOI: 10.1289/ehp.02110s61075 -
Scientific Reports Apr 2017We have developed a sensitive electrochemical sensor for Organophosphorus pesticide methyl parathion (MP) using silver particles supported graphene nanoribbons...
We have developed a sensitive electrochemical sensor for Organophosphorus pesticide methyl parathion (MP) using silver particles supported graphene nanoribbons (Ag@GNRs). The Ag@GNRs nanocomposite was prepared through facile wet chemical strategy and characterized by TEM, EDX, XRD, Raman, UV-visible, electrochemical and impedance spectroscopies. The Ag@GNRs film modified screen printed carbon electrode (SPCE) delivers excellent electrocatalytic ability to the reduction of MP. The Ag@GNRs/SPCE detects sub-nanomolar concentrations of MP with excellent selectivity. The synergic effects between special electrocatalytic ability of Ag and excellent physicochemical properties of GNRs (large surface area, high conductivity, high area-normalized edge-plane structures and abundant catalytic sites) make the composite highly suitable for MP sensing. Most importantly, the method is successfully demonstrated in vegetables and fruits which revealed its potential real-time applicability in food analysis.
Topics: Biosensing Techniques; Fruit; Methyl Parathion; Nanocomposites; Nanotubes, Carbon; Vegetables
PubMed: 28425441
DOI: 10.1038/srep46471 -
Analytical Methods : Advancing Methods... Jul 2021In this study, magnetic Fe3O4@SiO2@β-cyclodextrin copolymerized microparticles were synthesized and applied for the extraction of methyl parathion and fenthion in...
In this study, magnetic Fe3O4@SiO2@β-cyclodextrin copolymerized microparticles were synthesized and applied for the extraction of methyl parathion and fenthion in lettuce samples followed by HPLC-UV detection. The magnetic β-cyclodextrin copolymerized microparticles were prepared by dispersion polymerization with acryloyl β-cyclodextrin as the functional monomer and ethylene glycol dimethyacrylate as the crosslinker. The composite magnetic microparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, magnetic measurement, and thermogravimetric analysis, and used as the adsorbent of magnetic solid-phase extraction (MSPE) for methyl parathion and fenthion. The extraction conditions including sample pH and ionic strength, desorption solvent type and volume, and adsorption and desorption times were optimized. Under the optimal extraction conditions, an MSPE-HPLC-UV method was developed for the detection of methyl parathion and fenthion in lettuce. Wide linear ranges of 1.0-200 μg kg-1 (R2 = 0.9998) for methyl parathion and 1.5-200 μg kg-1 (R2 = 0.9978) for fenthion were obtained and the limits of detection were 0.3 μg kg-1 for methyl parathion and 0.5 μg kg-1 for fenthion in lettuce, respectively. The proposed method was applied for the determination of methyl parathion and fenthion in lettuce with satisfactory recoveries between 89.2-101.2%, and relative standard deviations were less than 9.1%. Thus, the MSPE-HPLC-UV method has high accuracy and sensitivity for the analysis of methyl parathion and fenthion in lettuce samples.
Topics: Fenthion; Lactuca; Limit of Detection; Magnetic Phenomena; Methyl Parathion; Silicon Dioxide; Solid Phase Extraction; beta-Cyclodextrins
PubMed: 34114573
DOI: 10.1039/d1ay00681a -
Biosensors & Bioelectronics Nov 2020A quick electrochemical sensing tool by utilizing novel bioelectrode based on redox active protein hemoglobin (Hb) has been offered here for the determination of...
Electrochemical detection of methyl parathion via a novel biosensor tailored on highly biocompatible electrochemically reduced graphene oxide-chitosan-hemoglobin coatings.
A quick electrochemical sensing tool by utilizing novel bioelectrode based on redox active protein hemoglobin (Hb) has been offered here for the determination of methylparathion (MP). The bioelectrode has been designed by immobilizing Hb on electrochemically reduced graphene oxide-chitosan (ERGO-CS/Hb/FTO) based biocompatible coatings. Fourier transform-infrared analyses (FTIR), field emission scanning electron microscopy (FESEM), UV-visible and electrochemical characterization reveal the successful grafting of ERGO-CS/Hb/FTO. A detailed impedimetric analysis shows low charge transfer resistance (R) and solution resistance (Rs) for the fabricated biosensor, thus pointing towards improved electrochemical performance and sensitivity. In-depth elucidation of redox analysis has been presented in terms of surface concentration of redox moiety (2.92 × 10 mol cm) and heterogeneous electron transfer rate constant (0.0032 s) which indicate enhanced surface coverage and better charge transfer properties of the proposed electrochemical biosensor. The sensor is equipped with a low limit of detection of 79.77 nM and a high sensitivity of 45.77 Acm μM with excellent reproducibility. The modified biosensor also offered its credibility towards detection of MP in vegetable samples with recovery (%) ranging from 94% to 101%. The designed biosensor hereby, evolves as a promising approach for the recognition of MP.
Topics: Biosensing Techniques; Chitosan; Electrochemical Techniques; Electrodes; Graphite; Hemoglobins; Methyl Parathion; Nanocomposites; Reproducibility of Results
PubMed: 32841783
DOI: 10.1016/j.bios.2020.112486