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Life Sciences Jan 2011Methamidophos (Meth) is a toxic organophosphorus compound (OP) that inhibits acetylcholinesterase enzyme (AChE) and induces neurotoxicity. As the mechanism of its...
AIMS
Methamidophos (Meth) is a toxic organophosphorus compound (OP) that inhibits acetylcholinesterase enzyme (AChE) and induces neurotoxicity. As the mechanism of its neurotoxic effects is not well understood, the aim of the present study was to evaluate the effects of Meth on glutamate and gamma aminobutyric acid (GABA) uptake and correlate with cell viability and AChE and Na(+)/K(+)-ATPase enzyme activities in striatum and hippocampus slices exposed to low concentrations (0.05 to 1.0 μM) of Meth.
MAIN METHODS
Hippocampal and striatal slices of rat brain were exposed to Meth for 5 min ([(3)H]Glutamate uptake) or 15 min ([(3)H]GABA uptake) for assays. The enzyme activities and cell viability were also accessed at both times in hippocampal and striatal slices and homogenates.
KEY FINDINGS
At concentrations that did not inhibit AChE, Meth caused changes in glutamate uptake in striatal (0.05 and 1.0 μM Meth) and hippocampal (1.0 μM Meth) slices. GABA uptake was increased by the pesticide in striatum at 0.5 and 1.0 μM and in hippocampus at 0.05 μM. After 3.5h of Meth exposure, striatal and hippocampal cells showed no changes in viability as well as no inhibition of Na(+)/K(+)-ATPase were observed after 5 or 15 min exposure to Meth in the same brain structures.
SIGNIFICANCE
Results suggest that Meth, even without changing the AChE activity can modify somehow the neurotransmitters uptake. However, further studies are necessary to clarify if this modulation in glutamate or GABA uptake may be responsible to cause some disturbance in behavior or in other neurochemical parameters following low Meth exposure in vivo.
Topics: Acetylcholinesterase; Angiotensin-Converting Enzyme Inhibitors; Animals; Cell Survival; Corpus Striatum; Dose-Response Relationship, Drug; Glutamic Acid; Hippocampus; Male; Mitochondria; Neurotransmitter Agents; Organothiophosphorus Compounds; Rats; Rats, Wistar; Sodium-Potassium-Exchanging ATPase; gamma-Aminobutyric Acid
PubMed: 21075126
DOI: 10.1016/j.lfs.2010.10.031 -
The Science of the Total Environment Nov 2020During water years (WY) 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network - Rivers and...
During water years (WY) 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network - Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic and acute toxicity to three taxonomic groups - fish, cladocerans, and benthic invertebrates. For invertebrates (either cladocerans, benthic invertebrates, or both), the maximum PTI score exceeded the predicted acute toxicity screening level at 18 of the 72 sites (25%) at some point during WY 2013-2017. The predicted toxicity of a single pesticide compound was found to overwhelm the toxicity of other pesticides in the mixtures after concentrations were toxicity weighted. For this study, about 71%, 72%, and 92% of the Fish-, Cladoceran-, and Benthic Invertebrate-PTI scores, respectively, had one pesticide compound primarily contributing to sample potential toxicity (>50%). There were 17 (13 insecticides, 2 herbicides, 1 fungicide, and 1 synergist) of the 221 pesticide compounds analyzed that were the primary drivers of potential toxicity in each water sample in which the PTI and TUmax (toxic unit score for the pesticide that makes the single largest contribution to the PTI) scores were above predicted chronic (>0.1) or acute (>1) toxicity levels for one of the three taxa. For cladocerans and benthic invertebrates, the drivers of predicted chronic (>0.1) and acute (>1) PTIs were mostly insecticides. For cladocerans, the pesticide compounds driving the PTI scores were bifenthrin, carbaryl, chlorpyrifos, diazinon, dichlorvos, dicrotophos, diflubenzuron, flubendiamide, and tebupirimfos. For benthic invertebrates, atrazine (an herbicide), as well as the insecticides - bifenthrin, carbaryl, carbofuran, chlorpyrifos, diazinon, dichlorvos, fipronil, imidacloprid, and methamidophos - were the drivers of predicted toxicity. For fish, there were three pesticide types that contributed the most to predicted chronic (>0.1) PTIs - acetochlor, an herbicide; carbendazim, a fungicide degradate; and piperonylbutoxide, a synergist.
Topics: Animals; Environmental Monitoring; Pesticides; Rivers; United States; Water; Water Pollutants, Chemical
PubMed: 32943215
DOI: 10.1016/j.scitotenv.2020.141285 -
RSC Advances Apr 2022A colloidal silver nanoparticle (AgNP)-based lateral flow immunoassay (LFIA) was evaluated in terms of the rapid detection of profenofos (PEO) pesticide residue in...
A colloidal silver nanoparticle (AgNP)-based lateral flow immunoassay (LFIA) was evaluated in terms of the rapid detection of profenofos (PEO) pesticide residue in vegetables. Colloidal AgNPs, of a diameter of approximately 20 nm, were surface-modified with trisodium citrate dehydrate (TSC) in order to improve their stability and dispersion. An anti-profenofos polyclonal antibody (pAb) was successfully immobilized on the surface of the AgNPs by ionic interaction and characterized using UV-vis, SEM, TEM, FTIR and XPS analyses. Surface modification of Ag-pAb conjugates of varying pH, pAb content and cross-reactivity was employed to design and prepare labels for use in an LFIA to examine whether these factors affect the performance of the assay. The visible detection limit and optical detection limit of the PEO test strip were 0.20 and 0.01 ppm, respectively, in PEO standard solution. This assay showed no cross-reaction with omethoate, methamidophos or pyraclofos. Finally, the PEO test strip was effectively applied for the detection of PEO in liquid vegetables A and B, with optical detection limits of 0.09 and 0.075 ppm, respectively.
PubMed: 35497005
DOI: 10.1039/d2ra01654k -
Frontiers in Bioengineering and... 2022O-Acetylhomoserine (OAH) is an important platform chemical for the synthesis of L-methamidophos and l-methionine. It has been produced efficiently in . However, a wider...
O-Acetylhomoserine (OAH) is an important platform chemical for the synthesis of L-methamidophos and l-methionine. It has been produced efficiently in . However, a wider range of key factors had not been identified, limiting further increases in OAH production. This study successfully identified some limiting factors and regulated them to improve OAH titer. Firstly, an efficient clustered regularly interspaced short palindromic repeats/dead CRISPR associated protein 9 (CRISPR-dCas9) system was constructed and used to identify the key genes in central metabolism and branch pathways associated with OAH biosynthesis. Then, the gene involved in TCA cycle was identified as the most critical gene. A sequential promoter P, which showed different transcriptional intensity in different strain growth periods, was used to control the expression of gene, resulting in OAH production of 7.0 g/L at 48 h. Finally, the OAH titer of the engineered strain reached 25.9 g/L at 72 h in a 5-L bioreactor. These results show that the identification and regulation of key genes are critical for OAH biosynthesis, which would provide a better research basis for the industrial production of OAH in .
PubMed: 36185436
DOI: 10.3389/fbioe.2022.978686 -
Toxicology Feb 2012The current Organisation for Economic Co-operation and Development (OECD) guidelines for evaluating organophosphorus-induced delayed neuropathy (OPIDN) require the... (Comparative Study)
Comparative Study
The current Organisation for Economic Co-operation and Development (OECD) guidelines for evaluating organophosphorus-induced delayed neuropathy (OPIDN) require the observation of dosed animals over several days and the sacrifice of 48 hens. Adhering to these protocols in tests with enantiomers is difficult because large quantities of the compound are needed and many animals must be utilized. Thus, developing an in vitro screening protocol to evaluate chiral organophosphorus pesticides (OPs) that can induce delayed neuropathy is important. This work aimed to evaluate, in blood and brain samples from hens, human blood, and human cell culture samples, the potential of the enantiomeric forms of methamidophos to induce acetylcholinesterase (AChE) inhibition and/or delayed neurotoxicity. Calpain activation was also evaluated in the hen brain and SH-SY5Y human neuroblastoma cells. The ratio between the inhibition of neuropathy target esterase (NTE) and AChE activities by the methamidophos enantiomers was evaluated as a possible indicator of the enantiomers' abilities to induce OPIDN. The (-)-methamidophos exhibited an IC(50) value approximately 6 times greater than that of the (+)-methamidophos for the lymphocyte NTE (LNTE) of hens, and (+)-methamidophos exhibited an IC(50) value approximately 7 times larger than that of the (-)-methamidophos for the hen brain AChE. The IC(50) values were 7 times higher for the human erythrocyte AChE and 5 times higher for AChE in the SH-SY5Y human neuroblastoma cells. Considering the esterases inhibition and calpain results, (+)-methamidophos would be expected to have a greater ability to induce OPIDN than the (-)-methamidophos in humans and in hens.
Topics: Acetylcholinesterase; Animals; Brain; Calpain; Cell Line, Tumor; Chickens; Cholinesterase Inhibitors; Female; Humans; Inhibitory Concentration 50; Insecticides; Least-Squares Analysis; Neurotoxicity Syndromes; Organothiophosphorus Compounds; Stereoisomerism
PubMed: 22198100
DOI: 10.1016/j.tox.2011.12.004 -
Chemosphere Oct 2013Pentatomid stinkbugs are important predators of defoliating caterpillars in agricultural and forestry systems, and knowledge of the impact of insecticides on natural...
Pentatomid stinkbugs are important predators of defoliating caterpillars in agricultural and forestry systems, and knowledge of the impact of insecticides on natural enemies is important information for integrated pest management (IPM) programs. Thus, we assessed the toxicity and behavioral sublethal response of the predators Podisus nigrispinus and Supputius cincticeps exposed to deltamethrin, methamidophos, spinosad and chlorantraniliprole, insecticides commonly used to control the velvetbean caterpillar (Anticarsia gemmatalis) in soybean crops. With the exception of deltamethrin for S. cincticeps, all insecticides showed higher acute toxicity to the prey than to these natural enemies providing effective control of A. gemmatalis. The recommended field concentration of deltamethrin, methamidophos and spinosad for controlling A. gemmatalis caused 100% mortality of P. nigrispinus and S. cincticeps nymphs. Chlorantraniliprole was the less toxic and the most selective insecticide to these predators resulting in mortalities of less than 10% when exposed to 10× the recommended field concentration for a period of 72 h. Behavioral pattern changes in predators were found for all insecticides, especially methamidophos and spinosad, which exhibited irritability (i.e., avoidance after contact) to both predator species. However, insecticide repellence (i.e., avoidance without contact) was not observed in any of the insects tested. The lethal and sublethal effects of pesticides on natural enemies is of great importance for IPM, and our results indicate that substitution of pyrethroid and organophosphate insecticides at their field rates by chlorantraniliprole may be a key factor for the success of IPM programs of A. gemmatalis in soybeans.
Topics: Animals; Behavior, Animal; Drug Combinations; Heteroptera; Insecticides; Macrolides; Nitriles; Organothiophosphorus Compounds; Pyrethrins
PubMed: 23880241
DOI: 10.1016/j.chemosphere.2013.05.075 -
Journal of Insect Science (Online) 2015Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod...
Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon-Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots.
Topics: Agriculture; Animals; Arthropods; Biodiversity; Brazil; Ecosystem; Fabaceae; Insecticides; Organothiophosphorus Compounds; Pyrethrins
PubMed: 25700537
DOI: 10.1093/jisesa/ieu172 -
3 Biotech Aug 2017The present study was intended to investigate the biodegradation of acephate in aqueous media in the presence and in the absence of metal ions [Fe(III) and Cu(II)], and...
The present study was intended to investigate the biodegradation of acephate in aqueous media in the presence and in the absence of metal ions [Fe(III) and Cu(II)], and humic acid (HA). Biodegradations were performed using PS-5 (PS-5) isolated from the heavy metal polluted site. Biodegradations were monitored by UV-Visible, FTIR, and electron spray ionization-mass spectrometry (ESI-MS) analyses. ESI-MS analysis revealed that PS-5 degraded acephate to two metabolites showing intense ions at mass-to-charge ratios (/) 62 and 97. The observed kinetic was the pseudo-first order, and half-life periods () were 2.79 d (of PS-5 + acephate), 3.45 d [of PS-5 + acephate + Fe(III)], 3.16 d [of PS-5 + acephate + Cu(II)], and 5.54 d (of PS-5 + acephate + HA). A significant decrease in degradation rate of acephate was noticed in the presence of HA, and the same was confirmed by UV-Visible and TGA analyses. Strong aggregation behavior of acephate with humic acid in aqueous media was the major cause behind the slow degradation rate of acephate . New results on acephate metabolism by strain PS-5 in the presence and in the absence of metal ions [Fe(III) and Cu(II)] and humic acid were obtained. Results confirmed that strain PS-5 was capable of mineralization of the acephate without formation of toxic metabolite methamidophos. More significantly, the strain PS-5 could be useful as potential biological agents in effective bioremediation campaign for multi-polluted environments.
PubMed: 28744429
DOI: 10.1007/s13205-017-0900-9 -
Biosensors Feb 2023Analytical methods for detecting neurotransmitters (NTs) and organophosphorus (OP) pesticides with high sensitivity are vitally necessary for the rapid identification of...
Analytical methods for detecting neurotransmitters (NTs) and organophosphorus (OP) pesticides with high sensitivity are vitally necessary for the rapid identification of physical, mental, and neurological illnesses, as well as to ensure food safety and safeguard ecosystems. In this work, we developed a supramolecular self-assembled system (SupraZyme) that exhibits multi-enzymatic activity. SupraZyme possesses the ability to show both oxidase and peroxidase-like activity, which has been employed for biosensing. The peroxidase-like activity was used for the detection of catecholamine NTs, epinephrine (EP), and norepinephrine (NE) with a detection limit of 6.3 µM and 1.8 µM, respectively, while the oxidase-like activity was utilized for the detection of organophosphate pesticides. The detection strategy for OP chemicals was based on the inhibition of acetylcholine esterase (AChE) activity: a key enzyme that is responsible for the hydrolysis of acetylthiocholine (ATCh). The corresponding limit of detection of paraoxon-methyl (POM) and methamidophos (MAP) was measured to be 0.48 ppb and 15.8 ppb, respectively. Overall, we report an efficient supramolecular system with multiple enzyme-like activities that provide a versatile toolbox for the construction of sensing platforms for the colorimetric point-of-care detection of both NTs and OP pesticides.
Topics: Pesticides; Organophosphorus Compounds; Colorimetry; Ecosystem; Acetylcholinesterase; Oxidoreductases; Metals; Biosensing Techniques; Peroxidases
PubMed: 36832043
DOI: 10.3390/bios13020277 -
Analytical and Bioanalytical Chemistry May 2021Mycotoxins and pesticides regularly co-occur in agricultural products worldwide. Thus, humans can be exposed to both toxic contaminants and pesticides simultaneously,...
Development, validation, and application of a multi-method for the determination of mycotoxins, plant growth regulators, tropane alkaloids, and pesticides in cereals by two-dimensional liquid chromatography tandem mass spectrometry.
Mycotoxins and pesticides regularly co-occur in agricultural products worldwide. Thus, humans can be exposed to both toxic contaminants and pesticides simultaneously, and multi-methods assessing the occurrence of various food contaminants and residues in a single method are necessary. A two-dimensional high performance liquid chromatography tandem mass spectrometry method for the analysis of 40 (modified) mycotoxins, two plant growth regulators, two tropane alkaloids, and 334 pesticides in cereals was developed. After an acetonitrile/water/formic acid (79:20:1, v/v/v) multi-analyte extraction procedure, extracts were injected into the two-dimensional setup, and an online clean-up was performed. The method was validated according to Commission Decision (EC) no. 657/2002 and document N° SANTE/12682/2019. Good linearity (R > 0.96), recovery data between 70-120%, repeatability and reproducibility values < 20%, and expanded measurement uncertainties < 50% were obtained for a wide range of analytes, including very polar substances like deoxynivalenol-3-glucoside and methamidophos. However, results for fumonisins, zearalenone-14,16-disulfate, acid-labile pesticides, and carbamates were unsatisfying. Limits of quantification meeting maximum (residue) limits were achieved for most analytes. Matrix effects varied highly (-85 to +1574%) and were mainly observed for analytes eluting in the first dimension and early-eluting analytes in the second dimension. The application of the method demonstrated the co-occurrence of different types of cereals with 28 toxins and pesticides. Overall, 86% of the samples showed positive findings with at least one mycotoxin, plant growth regulator, or pesticide.
Topics: Alkaloids; Chromatography, Liquid; Edible Grain; Food Contamination; Mycotoxins; Pesticides; Plant Growth Regulators; Reproducibility of Results; Tandem Mass Spectrometry; Tropanes
PubMed: 33713146
DOI: 10.1007/s00216-021-03239-1