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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 -
Bioscience, Biotechnology, and... 2011An analytical methodology for the analysis of methamidophos in water and soil samples incorporating a molecularly imprinted solid-phase extraction process using...
An analytical methodology for the analysis of methamidophos in water and soil samples incorporating a molecularly imprinted solid-phase extraction process using methamidophos-imprinted polymer was developed. Binding study demonstrated that the polymer exhibited excellent affinity and high selectivity to the methamidophos. Evidence was also found by FT-IR analysis that hydrogen bonding between the CO(2)H in the polymer cavities and the NH(2) and P=O of the template was the origin of methamidophos recognition. The use of molecularly imprinted solid-phase extraction improved the accuracy and precision of the GC method and lowered the limit of detection. The recovery of methamidophos extracted from a 10.0 g soil sample at the 100 ng/g spike level was 95.4%. The limit of detection was 3.8 ng/g. The recovery of methamidophos extracted from 100 mL tap and river water at 1 ng/mL spike level was 96.1% and 95.8%, and the limits of detection were 10 and 13 ng/L respectively. These molecularly imprinted solid-phase extraction procedures enabled selective extraction of polar methamidophos successfully from water and soil samples, demonstrating the potential of molecularly imprinted solid-phase extraction for rapid, selective, and cost-effective sample pretreatment.
Topics: Binding Sites; Chromatography, Gas; Fourier Analysis; Hydrogen Bonding; Hydrophobic and Hydrophilic Interactions; Limit of Detection; Molecular Imprinting; Organothiophosphorus Compounds; Polymers; Sensitivity and Specificity; Soil; Solid Phase Extraction; Water; Water Pollutants, Chemical; Water Purification
PubMed: 21389628
DOI: 10.1271/bbb.100668 -
Journal of Exposure Science &... Jul 2020The use of pesticides has increased during the past decades, also increasing the risk of exposure to toxic pesticides that can cause detrimental health effects in the...
The use of pesticides has increased during the past decades, also increasing the risk of exposure to toxic pesticides that can cause detrimental health effects in the future. This is of special concern among farmers in low-to-middle-income countries that may lack proper training in the safe use of these chemicals. To assess the situation in Bolivia a cross-sectional study in three agricultural communities was performed (n = 297). Handling, use of personal protective equipment (PPE) and pesticide exposure were assessed by a questionnaire and measurements of urinary pesticide metabolites (UPMs). Results showed that methamidophos (65%) and paraquat (52%) were the most commonly used pesticides and that 75% of the farmers combined several pesticides while spraying. Notably, only 17% of the farmers used recommended PPEs while 84% reported to have experienced symptoms of acute pesticide poisoning after spraying. UPM measurements indicated high levels of exposure to chlorpyrifos, pyrethroids and 2,4D and that men generally were more highly exposed compared to women. Our study demonstrates that farmers who are better at following recommendations for pesticide handling and use of PPE had a significantly lower risk of having high UPM levels of most measured pesticides. Our results thus confirm the need of proper training of farmers in low-to-middle-income countries in proper protection and pesticide handling in order to reduce exposure levels and health problems.
Topics: Adult; Agriculture; Biomarkers; Bolivia; Cross-Sectional Studies; Farmers; Female; Health Knowledge, Attitudes, Practice; Hispanic or Latino; Humans; Male; Occupational Exposure; Pesticides; Surveys and Questionnaires
PubMed: 30787424
DOI: 10.1038/s41370-019-0128-3 -
Applied and Environmental Microbiology Mar 2012De-esterification is an important degradation or detoxification mechanism of sulfonylurea herbicide in microbes and plants. However, the biochemical and molecular...
De-esterification is an important degradation or detoxification mechanism of sulfonylurea herbicide in microbes and plants. However, the biochemical and molecular mechanisms of sulfonylurea herbicide de-esterification are still unknown. In this study, a novel esterase gene, sulE, responsible for sulfonylurea herbicide de-esterification, was cloned from Hansschlegelia zhihuaiae S113. The gene contained an open reading frame of 1,194 bp, and a putative signal peptide at the N terminal was identified with a predicted cleavage site between Ala37 and Glu38, resulting in a 361-residue mature protein. SulE minus the signal peptide was synthesized in Escherichia coli BL21 and purified to homogeneity. SulE catalyzed the de-esterification of a variety of sulfonylurea herbicides that gave rise to the corresponding herbicidally inactive parent acid and exhibited the highest catalytic efficiency toward thifensulfuron-methyl. SulE was a dimer without the requirement of a cofactor. The activity of the enzyme was completely inhibited by Ag(+), Cd(2+), Zn(2+), methamidophos, and sodium dodecyl sulfate. A sulE-disrupted mutant strain, ΔsulE, was constructed by insertion mutation. ΔsulE lost the de-esterification ability and was more sensitive to the herbicides than the wild type of strain S113, suggesting that sulE played a vital role in the sulfonylurea herbicide resistance of the strain. The transfer of sulE into Saccharomyces cerevisiae BY4741 conferred on it the ability to de-esterify sulfonylurea herbicides and increased its resistance to the herbicides. This study has provided an excellent candidate for the mechanistic study of sulfonylurea herbicide metabolism and detoxification through de-esterification, construction of sulfonylurea herbicide-resistant transgenic crops, and bioremediation of sulfonylurea herbicide-contaminated environments.
Topics: Cations, Divalent; Cloning, Molecular; DNA, Bacterial; Enzyme Inhibitors; Escherichia coli; Esterases; Esterification; Gene Deletion; Herbicides; Metals; Methylocystaceae; Molecular Sequence Data; Open Reading Frames; Organothiophosphorus Compounds; Protein Multimerization; Saccharomyces cerevisiae; Sequence Analysis, DNA; Sodium Dodecyl Sulfate; Substrate Specificity; Sulfonylurea Compounds
PubMed: 22247165
DOI: 10.1128/AEM.07440-11 -
Turkish Journal of Medical Sciences 2014To evaluate the usefulness of plasma glucose and serum cholinesterase levels as predictors of organophosphate-induced intermediate syndrome.
AIM
To evaluate the usefulness of plasma glucose and serum cholinesterase levels as predictors of organophosphate-induced intermediate syndrome.
MATERIALS AND METHODS
Seventy-one organophosphate poisoning patients who were admitted to our emergency department during a 4-year period were evaluated retrospectively. Four patients were excluded from the study due to a lack of medical records. Categorical variables were analyzed using the chi-square test and nonparametric variables were analyzed using the Mann-Whitney U test.
RESULTS
Thirty-five (52.2%) patients were male and 32(47.8%) were female. Patients had a mean age of 39.4 ± 15.9 years and 70.1% of the patients were married. Oral intake (68.7%) was the most common method of intoxication, and attempted suicide (67.2%) was the most common cause. The most common organophosphates were methamidophos (20.8%), dichlorvos (19.4%), parathion (7.5%), and methyl parathion (7.5%). Fifty-seven (85%) patients were treated in the emergency observation unit and 10 (15%) patients were admitted to the intensive care unit. Eleven (16%) patients developed intermediate syndrome and had significantly lower levels of serum cholinesterase (P < 0.01) and higher blood glucose levels (P = 0.037).
CONCLUSION
Initial serum cholinesterase and glucose levels measured in the emergency department may be a useful marker in predicting organophosphate-induced intermediate syndrome.
Topics: Adult; Blood Glucose; Cholinesterase Reactivators; Cholinesterases; Emergency Service, Hospital; Female; Humans; Male; Muscle Weakness; Organophosphate Poisoning; Oximes; Patient Admission; Respiratory Paralysis; Retrospective Studies; Suicide, Attempted; Turkey; Vomiting
PubMed: 25536737
DOI: 10.3906/sag-1211-31 -
Exposure to methamidophos at adulthood adversely affects serotonergic biomarkers in the mouse brain.Neurotoxicology Dec 2011Epidemiologic studies describe a potential risk of depression and suicide in farm workers exposed to organophosphates (OPs). In a previous study we observed an increase...
Epidemiologic studies describe a potential risk of depression and suicide in farm workers exposed to organophosphates (OPs). In a previous study we observed an increase in depressive-like behavior in adult mice exposed to the OP pesticide methamidophos. Considering the association between depression and the serotonergic (5HT) system, in the present study we investigated whether a subchronic exposure to methamidophos affects the serotonergic system of adult mice. From postnatal day 60 to 89 (PN60 to PN89), one of two concentrations of methamidophos (higher dose: 5.25 μg/ml; lower dose: 1.31 μg/ml) or vehicle was administered in the drinking water of male Swiss mice. We evaluated three serotonergic biomarkers during (PN89) and after (PN100) the exposure period: 5HT(1A) receptor binding with [(3)H]OH-DPAT, 5HT(2) receptor binding with [(3)H]ketanserin and 5HT transporter binding with [(3)H]paroxetine. Methamidophos elicited robust decreases in binding for all 5HT markers. These decreases were evident in brain regions containing 5HT cell bodies and dendritic arbors (midbrain, brainstem) as well as in the cerebral cortex, which contains 5HT projections. In the cerebral cortex, effects were identified in mice exposed to the higher dose of methamidophos while in the midbrain and brainstem, both doses elicited significant effects. Overall, effects were present both during and after exposure, even though there were some regional disparities regarding the persistence of effects. Our results indicate that exposure to methamidophos affects synaptic transmission promoting decreases of specific serotonergic biomarkers. These data suggest a mechanism of action of this pesticide that might explain the increased depressive-like behavior in adult mice.
Topics: Age Factors; Animals; Biomarkers; Brain; Depression; Down-Regulation; Insecticides; Male; Mice; Organothiophosphorus Compounds; Receptor, Serotonin, 5-HT1A; Receptors, Serotonin, 5-HT2; Risk Assessment; Risk Factors; Serotonin; Serotonin Plasma Membrane Transport Proteins; Synaptic Transmission; Time Factors
PubMed: 21871486
DOI: 10.1016/j.neuro.2011.08.002 -
Zeitschrift Fur Naturforschung. C,... 1987The cytogenetic effect of the insecticide methamidophos (0,S-dimethylphosphoroamidothiolate) was studied in mouse bone marrow and mouse spleen cells in culture. In vivo...
The cytogenetic effect of the insecticide methamidophos (0,S-dimethylphosphoroamidothiolate) was studied in mouse bone marrow and mouse spleen cells in culture. In vivo the ability of methamidophos to induce micronuclei and sisterchromatid exchange in mouse bone marrow was investigated. In vitro mouse spleen cells in culture were used to assess the ability of the insecticide to induce chromosomal aberrations and sister chromatid exchange. Three different routes of application for the pure insecticide were tested so as to cover the different possibilities for human exposure to the insecticide. Intraperitoneal, oral and dermal treatment with methamidophos caused toxicity to marrow as indicated by a significant increase in the percentage of polychromatic erythrocytes (PEs) over that of the control. Methamidophos showed mutagenic potential as evidenced by a positive response in the micronucleus and chromosomal aberrations assays. Thus, single and multiple i.p. injections at 6 and 4.5 mg methamidophos/kg body wt., oral administration of the insecticide for 14 consecutive days at a dietary level of 100 ppm and multiple dermal treatments (total 4) with 24 mg/kg body wt. induced a statistically significant increase in the frequency of PEs with micronuclei in mouse bone marrow. Moreover, the tested concentrations of methamidophos as low as 0.25 microgram/ml induced a high percentage of metaphases with chromosomal aberrations in cultured mouse spleen cells. Methamidophos is a weak inducer of SCEs in mouse bone marrow and cultured mouse spleen cells.
Topics: Animals; Bone Marrow; Bone Marrow Cells; Cell Nucleus; Cells, Cultured; Insecticides; Karyotyping; Lymphocytes; Mice; Organothiophosphorus Compounds; Polyploidy; Sister Chromatid Exchange; Spleen
PubMed: 2953131
DOI: 10.1515/znc-1987-1-205 -
Journal of Insect Science (Online) Nov 2018Propylaea japonica (Thunberg) was a dominant species among the predacious ladybirds in the fields and active from March to November during a year in Fuzhou, China....
Propylaea japonica (Thunberg) was a dominant species among the predacious ladybirds in the fields and active from March to November during a year in Fuzhou, China. Stability of insecticide resistance and vitality in adult P. japonica were investigated. The field ladybird P. japonica in Fuzhou, China, showed 9- to 16-fold resistance ratios to chlorpyrifos, 13- to 2,083-fold to methamidophos, 32- to 230-fold to fenvalerate, and 4- to 49-fold to avermectins, respectively, based on the field monitoring during 2004, 2009, and 2012, as compared with insecticide-susceptible F39 progenies. The resistance levels in the field P. japonica were high during May and November but low during summer. The population growth tendency index in field P. japonica was 0.8-fold as high as that in insecticide-susceptible P. japonica. The field P. japonica also showed high tolerance to the insecticide as compared with pest Lipaphis erysimi Kaltenbach and two parasitoids Diaeretiella rapae and Pachyneuron aphidis. Stable insecticide resistance levels and high vitality were found first in adult P. japonica with 1-, 30-, or 60-d-old adults, or among the adults developed form the eggs produced by newly emerged adults or by 60-d-old adults. Increased activity of glutathione S-transferases, carboxylesterases, and cytochrome P450 monooxygenases might be involved in the resistance of P. japonica. The results indicated that, in certain areas, inclusion of P. japonica for pest control in the integrated pest management would be highly recommended.
Topics: Animals; China; Coleoptera; Insecticide Resistance; Insecticides; Seasons
PubMed: 30535415
DOI: 10.1093/jisesa/iey109 -
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 -
Journal of Toxicologic Pathology Sep 2011Organophosphates such as methamidophos, usually used in the agricultural field, have harmful effects on humans. Exposures to insecticides has been associated with many...
Organophosphates such as methamidophos, usually used in the agricultural field, have harmful effects on humans. Exposures to insecticides has been associated with many disorders, including damage to the central and peripheral nervous system. Chronic exposure to organophosphates may lead to persistent neurological and neurobehavioral effects. This study was conducted to determine the effect of methamidophos on [(3)H]-dopamine (DA) and gamma aminobutyric acid (GABA) release from different brain regions after chronic exposure to it for 3, 6 or 9 months. After a six-month methamidophos treatment, the mice showed high susceptibility to convulsive seizures and a reduction in stimulated gamma aminobutyric acid release from the cerebral cortex and hippocampal slices, whereas stimulated (DA) release was slightly decreased from the striatum after three months of methamidophos exposure. The results indicate changes in gamma aminobutyric acid and dopamine neurotransmission, suggesting a specific neuronal damage.
PubMed: 22272056
DOI: 10.1293/tox.24.163