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EFSA Journal. European Food Safety... Oct 2018The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State the United... (Review)
Review
The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State the United Kingdom and co-rapporteur Member State Germany for the pesticide active substance methiocarb are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative use of methiocarb as an insecticide and a bird repellent on maize. The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.
PubMed: 32625712
DOI: 10.2903/j.efsa.2018.5429 -
Environmental Toxicology and... Jan 2016In this work, we examined the metabolism of the carbamate insecticides methiocarb and carbaryl by rat liver microsomes and plasma, and its effect on their...
In this work, we examined the metabolism of the carbamate insecticides methiocarb and carbaryl by rat liver microsomes and plasma, and its effect on their endocrine-disrupting activities. Methiocarb and carbaryl were not enzymatically hydrolyzed by rat liver microsomes, but were hydrolyzed by rat plasma, mainly to methylthio-3,5-xylenol (MX) and 1-naphthol, respectively. When methiocarb was incubated with rat liver microsomes in the presence of NADPH, methiocarb sulfoxide was formed. The hydrolysis product, MX, was also oxidized to the sulfoxide, 3,5-dimethyl-4-(methylsulfinyl)phenol (SP), by rat liver microsomes in the presence of NADPH. These oxidase activities were catalyzed by cytochrome P450 and flavin-containing monooxygenase. Methiocarb and carbaryl both exhibited estrogen receptor α (ERα) and ERβ agonistic activity. MX and 1-naphthol showed similar activities, but methiocarb sulfoxide and SP showed markedly decreased activities. On the other hand, methiocarb and carbaryl exhibited potent antiandrogenic activity in the concentration range of 1×10(-6)-3×10(-5) M. Their hydrolysis products, MX, and 1-naphthol also showed high activity, equivalent to that of flutamide. However, methiocarb sulfoxide and SP showed relatively low activity. Thus, hydrolysis of methiocarb and carbaryl and oxidation of methiocarb to the sulfoxide markedly modified the estrogenic and antiandrogenic activities of methiocarb and carbaryl.
Topics: Androgen Antagonists; Animals; CHO Cells; Carbaryl; Cell Line; Cricetulus; Cytochrome P-450 Enzyme System; Estrogens; Humans; Hydrolysis; In Vitro Techniques; Liver; MCF-7 Cells; Methiocarb; NADP; Oxygenases; Plasma; Rats
PubMed: 26774076
DOI: 10.1016/j.etap.2015.08.014 -
Molecules (Basel, Switzerland) Dec 2020This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped...
This paper studies the degradation of methiocarb, a highly hazardous pesticide found in waters and wastewaters, through an electro-Fenton process, using a boron-doped diamond anode and a carbon felt cathode; and evaluates its potential to reduce toxicity towards the model organism . The influence of applied current density and type and concentration of added iron source, Fe(SO)·5HO or FeCl·6HO, is assessed in the degradation experiments of methiocarb aqueous solutions. The experimental results show that electro-Fenton can be successfully used to degrade methiocarb and to reduce its high toxicity towards . Total methiocarb removal is achieved at the applied electric charge of 90 C, and a 450× reduction in the acute toxicity towards , on average, from approximately 900 toxic units to 2 toxic units, is observed at the end of the experiments. No significant differences are found between the two iron sources studied. At the lowest applied anodic current density, 12.5 A m, an increase in iron concentration led to lower methiocarb removal rates, but the opposite is found at the highest applied current densities. The highest organic carbon removal is obtained at the lowest applied current density and added iron concentration.
Topics: Animals; Biodegradation, Environmental; Daphnia; Ecotoxicology; Electrochemistry; Electrodes; Insecticides; Methiocarb; Water Pollutants, Chemical
PubMed: 33322793
DOI: 10.3390/molecules25245893 -
The Journal of Toxicological Sciences 2016The oxidative, reductive, and hydrolytic metabolism of methiocarb and the hydrolytic metabolism of carbaryl by liver microsomes and plasma of rats or humans were...
The oxidative, reductive, and hydrolytic metabolism of methiocarb and the hydrolytic metabolism of carbaryl by liver microsomes and plasma of rats or humans were examined. The effects of the metabolism of methiocarb and carbaryl on their nuclear receptor activities were also examined. When methiocarb was incubated with rat liver microsomes in the presence of NADPH, methiocarb sulfoxide, and a novel metabolite, methiocarb sulfone were detected. Methiocarb sulfoxide was oxidized to the sulfone by liver microsomes and reduced back to methiocarb by liver cytosol. Thus, the interconversion between methiocarb and the sulfoxide was found to be a new metabolic pathway for methiocarb by liver microsomes. The product of methiocarb hydrolysis, which is methylthio-3,5-xylenol (MX), was also oxidized to sulfoxide form by rat liver microsomes. The oxidations were catalyzed by human flavin-containing monooxygenase isoform (FMO1). CYP2C19, which is a human cytochrome P450 (CYP) isoform, catalyzed the sulfoxidations of methiocarb and MX, while CYP1A2 also exhibited oxidase activity toward MX. Methiocarb and carbaryl were not enzymatically hydrolyzed by the liver microsomes, but they were mainly hydrolyzed by plasma and albumin to MX and 1-naphthol, respectively. Both methiocarb and carbaryl exhibited PXR and PPARα agonistic activities; however, methiocarb sulfoxide and sulfone showed markedly reduced activities. In fact, when methiocarb was incubated with liver microsomes, the receptor activities were decreased. In contrast, MX and 1-naphthol showed nuclear receptor activities equivalent to those of their parent carbamates. Thus, the hydrolysis of methiocarb and carbaryl and the oxidation of methiocarb markedly modified their nuclear receptor activities.
Topics: Animals; Biotransformation; COS Cells; Carbaryl; Chlorocebus aethiops; Cholinesterase Inhibitors; Constitutive Androstane Receptor; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP2C19; Humans; Hydrolysis; Liver; Male; Methiocarb; Microsomes, Liver; Oxidation-Reduction; PPAR alpha; Pregnane X Receptor; Rats, Sprague-Dawley; Receptors, Cytoplasmic and Nuclear; Receptors, Steroid; Transfection
PubMed: 27665777
DOI: 10.2131/jts.41.677 -
Food and Chemical Toxicology : An... Jul 2009Methiocarb, is used worldwide in agriculture and health programs. Besides its advantages in the agriculture, it causes several toxic effects. In this study, we aimed to...
Methiocarb, is used worldwide in agriculture and health programs. Besides its advantages in the agriculture, it causes several toxic effects. In this study, we aimed to investigate subacute effects of methiocarb on lipid peroxidation, reduced glutathione (GSH), antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) and histopathological changes in rat tissues. Moreover, we examined the possible protective effects of vitamin E and taurine on methiocarb-induced oxidative damage in rat tissues. Rats were randomly divided into six groups as follows; I-control group; II-methiocarb group; III-vitamin E group; IV-vitamin E+methiocarb group; V-taurine group and VI-taurine+methiocarb group. Methiocarb significantly increased lipid peroxidation in liver and kidney when compared to control groups. Levels of GSH and activities of SOD, CAT and GSH-Px were found to be decreased, while GSH-Rd remained unchanged in rat liver and kidney treated with methiocarb. Pretreatment of vitamin E and taurine resulted in a significant decrease on lipid peroxidation, alleviating effects on GSH and antioxidant enzymes. The degenerative histological changes were less in liver than kidney of rats treated with methiocarb. Pretreatment of vitamin E and taurine showed a protective effect on the histological changes in kidney comparing to the liver of rats treated with methiocarb.
Topics: Animals; Antioxidants; Chemical and Drug Induced Liver Injury; Glutathione; Insecticides; Kidney Diseases; Lipid Peroxidation; Male; Methiocarb; Oxidative Stress; Rats; Rats, Wistar; Taurine; Vitamin E
PubMed: 19394395
DOI: 10.1016/j.fct.2009.04.018 -
Journal of Chromatography. B,... Aug 2017A simultaneous analytical method was developed for the determination of methiocarb and its metabolites, methiocarb sulfoxide and methiocarb sulfone, in five livestock...
Simultaneous quantification of methiocarb and its metabolites, methiocarb sulfoxide and methiocarb sulfone, in five food products of animal origin using tandem mass spectrometry.
A simultaneous analytical method was developed for the determination of methiocarb and its metabolites, methiocarb sulfoxide and methiocarb sulfone, in five livestock products (chicken, pork, beef, table egg, and milk) using liquid chromatography-tandem mass spectrometry. Due to the rapid degradation of methiocarb and its metabolites, a quick sample preparation method was developed using acetonitrile and salts followed by purification via dispersive- solid phase extraction (d-SPE). Seven-point calibration curves were constructed separately in each matrix, and good linearity was observed in each matrix-matched calibration curve with a coefficient of determination (R) ≥ 0.991. The limits of detection and quantification were 0.0016 and 0.005mg/kg, respectively, for all tested analytes in various matrices. The method was validated in triplicate at three fortification levels (equivalent to 1, 2, and 10 times the limit of quantification) with a recovery rate ranging between 76.4-118.0% and a relative standard deviation≤10.0%. The developed method was successfully applied to market samples, and no residues of methiocarb and/or its metabolites were observed in the tested samples. In sum, this method can be applied for the routine analysis of methiocarb and its metabolites in foods of animal origins.
Topics: Animals; Cattle; Chickens; Chromatography, Liquid; Food Analysis; Limit of Detection; Linear Models; Meat; Methiocarb; Milk; Reproducibility of Results; Swine; Tandem Mass Spectrometry
PubMed: 28666230
DOI: 10.1016/j.jchromb.2017.06.025 -
The Veterinary Record Nov 1986
Topics: Animals; Female; Horse Diseases; Horses; Insecticides; Methiocarb
PubMed: 3798705
DOI: 10.1136/vr.119.22.556 -
Australian Veterinary Journal Jun 2012Snail bait poisoning is rare in horses. Cases have been reported, but clinical signs and subsequent prognostic indicators have been poorly documented and must be...
Snail bait poisoning is rare in horses. Cases have been reported, but clinical signs and subsequent prognostic indicators have been poorly documented and must be extrapolated from cases in companion animals. We describe in detail the poisoning of a horse that consumed a lethal dose of the carbamate, methiocarb. There are currently no guidelines for treating equine methiocarb toxicoses, but the principles of management are based on supportive therapy.
Topics: Animals; Australia; Horse Diseases; Horses; Insecticides; Male; Methiocarb
PubMed: 22632285
DOI: 10.1111/j.1751-0813.2012.00910.x -
Journal of Economic Entomology Apr 2000Biochemical mechanisms associated with methiocarb resistance were examined in laboratory-selected and field populations of the western flower thrips, Frankliniella...
Biochemical mechanisms associated with methiocarb resistance were examined in laboratory-selected and field populations of the western flower thrips, Frankliniella occidentalis (Pergande). Seven populations were examined and they differed in their susceptibility to methiocarb by 30 times. Including the synergists piperonyl butoxide, a cytochrome P-450 monooxygenase inhibitor, or S,S,S-tributylphosphorotrithioate, an esterase inhibitor, in the methiocarb bioassays partially suppressed resistance in the most resistant populations. In vitro assays of general esterase, glutathione S-transferase, and acetylcholinesterase activities showed increased activity in some of the resistant populations and increased activity of the enzymes after methiocarb selection on one of the populations. Assays of acetylcholinesterase sensitivity to inhibition by methiocarb, dichlorvos, and eserine suggested insensitive acetylcholinesterase in two of the resistant populations. These results indicate that methiocarb resistance in F. occidentalis was polyfactorial and involved detoxification and altered target site. None of the biochemical assays showed interpopulation enzymatic differences strongly correlated with the level of methiocarb resistance. The possibilities for developing rapid biochemical diagnostic assays to detect methiocarb resistance in F. occidentalis are discussed.
Topics: Animals; Biological Assay; Insect Control; Insecta; Insecticide Resistance; Insecticides; Methiocarb
PubMed: 10826201
DOI: 10.1603/0022-0493-93.2.464 -
Journal of Agricultural and Food... Jan 2013The present work describes the development of an analytical method for the determination of methiocarb and its degradation products (methiocarb sulfoxide and methiocarb...
The present work describes the development of an analytical method for the determination of methiocarb and its degradation products (methiocarb sulfoxide and methiocarb sulfone) in banana samples, using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure followed by liquid chromatography coupled to photodiode array detector (LC-PAD). Calibration curves were linear in the range of 0.5-10 mg L⁻¹ for all compounds studied. The average recoveries, measured at 0.1 mg kg⁻¹ wet weight, were 92.0 (RSD = 1.8%, n = 3), 84.0 (RSD = 3.9%, n = 3), and 95.2% (RSD = 1.9%, n = 3) for methiocarb sulfoxide, methiocarb sulfone, and methiocarb, respectively. Banana samples treated with methiocarb were collected from an experimental field. The developed method was applied to the analysis of 24 samples (peel and pulp) and to 5 banana pulp samples. Generally, the highest levels were found for methiocarb sulfoxide and methiocarb. Methiocarb sulfone levels were below the limit of quantification, except in one sample (not detected).
Topics: Drug Stability; Food Contamination; Food Inspection; Fruit; Insecticides; Methiocarb; Molluscacides; Musa; Portugal; Sulfones
PubMed: 23252625
DOI: 10.1021/jf304027s