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Analytica Chimica Acta May 2021Herein, we originally aimed at developing fluorescence anisotropy biosensor platforms devoted to the homogeneous-phase detection of isocarbophos and phorate pesticides...
Herein, we originally aimed at developing fluorescence anisotropy biosensor platforms devoted to the homogeneous-phase detection of isocarbophos and phorate pesticides by using previously isolated DNA aptamers. To achieve this, two reporting approaches displaying very high generalizability features were implemented, based on either the complementary strand or the SYBR green intercalator displacement strategies. Unfortunately, none of the transduction methods led to phorate-dependent signals. Only the SYBR green displacement method provided a small output in the presence of isocarbophos, but at an analyte concentration greater than 100 μM. In order to identify the origin of such data, isothermal titration calorimetry (ITC) experiments were subsequently performed. It was shown that aptamers bind neither isocarbophos nor phorate in free solution with the claimed micromolar dissociation constants. This work puts forward some doubts about the previously described aptasensors that rely on the use of these functional DNA molecules. It also highlights the need to carefully investigate the binding capabilities of aptamers after their isolation and to include appropriate control experiments with scrambled or mutated oligonucleotides.
Topics: Aptamers, Nucleotide; Biosensing Techniques; DNA; Dissociative Disorders; Humans; Pesticides
PubMed: 33867041
DOI: 10.1016/j.aca.2021.338382 -
Food Chemistry Aug 2021The effects of alkaline and acidic electrolyzed water (AlEW, AcEW) treatment on the removal of pesticides (phorate, chlorpyrifos, lambda-cyhalothrin, cyfluthrin,...
The effects of alkaline and acidic electrolyzed water (AlEW, AcEW) treatment on the removal of pesticides (phorate, chlorpyrifos, lambda-cyhalothrin, cyfluthrin, procymidone, and chlorothalonil) and texture quality of fresh-cut cabbage, broccoli, and color pepper were investigated. AlEW efficiently removed pesticides from color pepper, whereas AcEW was the optimal treatment for pesticide removal from cabbage and broccoli. AcEW resulted in greater losses of pyrethroid and organophosphates than fungicides, while AlEW was superior for removing fungicides. The best pesticide removal from cabbage (72.28%-91.04%) was achieved by continuous oscillation treatment, while intermittent oscillation for 20 min achieved optimal results for broccoli and color pepper (72.28%-90.11% and 72.24%-88.12%, respectively). No significant deterioration in texture was detected in samples treated with electrolyzed water for 5-25 min. The results suggest that electrolyzed water treatment is effective for removing organophosphate, pyrethroid, and fungicide residues from fresh-cut vegetables while not negatively affecting their texture quality.
Topics: Electrolysis; Food Contamination; Fungicides, Industrial; Pesticides; Vegetables; Water; Water Purification
PubMed: 33714792
DOI: 10.1016/j.foodchem.2021.129408 -
Toxicology Mar 2021Organophosphorus compounds (OPs) include nerve agents and insecticides that potently inhibit acetylcholinesterase (AChE), an essential enzyme found throughout the...
Organophosphorus compounds (OPs) include nerve agents and insecticides that potently inhibit acetylcholinesterase (AChE), an essential enzyme found throughout the nervous system. High exposure levels to OPs lead to seizures, cardiac arrest, and death if left untreated. Oximes are a critical piece to the therapeutic regimen which remove the OP from the inhibited AChE and restore normal cholinergic function. The current oximes 2-PAM, MMB-4, TMB-4, HI-6, and obidoxime (OBD) have two drawbacks: lack of broad spectrum protection against multiple OP structures and poor brain penetration to protect against OP central neurotoxicity. An alternative strategy to enhance therapy is reactivation of serum butyrylcholinesterase (BChE). BChE is stoichiometrically inhibited by OPs with no apparent toxic result. Inhibition of BChE in the serum followed by reactivation could create a pseudo-catalytic scavenger allowing numerous regenerations of BChE to detoxify circulating OP molecules before they can reach target AChE. BChE in serum from rats, guinea pigs or humans was screened for the reactivation potential of our novel substituted phenoxyalkyl pyridinium oximes, plus 2-PAM, MMB-4, TMB-4, HI-6, and OBD (100μM) in vitro after inhibition by highly relevant surrogates of sarin, VX, and cyclosarin, and also DFP, and the insecticidal active metabolites paraoxon, phorate-oxon, and phorate-oxon sulfoxide. Novel oxime 15 demonstrated significant broad spectrum reactivation of OP-inhibited rat serum BChE while novel oxime 20 demonstrated significant broad spectrum reactivation of OP-inhibited human serum BChE. All tested oximes were poor reactivators of OP-inhibited guinea pig serum BChE. The bis-pyridinium oximes were poor BChE reactivators overall. BChE reactivation may be an additional mechanism to attenuate OP toxicity and contribute to therapeutic efficacy.
Topics: Animals; Butyrylcholinesterase; Cholinesterase Inhibitors; Guinea Pigs; Humans; Nerve Agents; Organophosphates; Oximes; Pyridinium Compounds; Rats
PubMed: 33592259
DOI: 10.1016/j.tox.2021.152719 -
Healthcare (Basel, Switzerland) Jan 2021Phorate is a systemic organophosphorus pesticide (OP) that acts by inhibiting cholinesterases. Recent studies have reported that long-term low/moderate exposure to OP...
Phorate is a systemic organophosphorus pesticide (OP) that acts by inhibiting cholinesterases. Recent studies have reported that long-term low/moderate exposure to OP could be correlated with impaired cardiovascular and pulmonary function and other neurological effects. A 70-year-old farmer died after an intention ingestion of a granular powder mixed with water. He was employed on a farm for over 50 years producing fruit and vegetables, and for about 20 years, he had also applied pesticides. In the last 15 years, he used phorate predominantly. The Phorate concentration detected in gastric contents was 3.29 µg/mL. Chronic exposure to phorate is experimentally studied by histopathological changes observed in the kidney. In the light of current literature, our case confirms that there is an association between renal damage and chronic exposure to phorate in a subject exposed for years to the pesticide. Autopsies and toxicological analyses play a key role in the reconstruction of the dynamics, including the cause of the death.
PubMed: 33572719
DOI: 10.3390/healthcare9020131 -
Journal of Food Protection Mar 2021We evaluated fresh vegetables for residues of 18 pesticides with different chemical structures, including organochlorine pesticides, organophosphorus pesticides,...
ABSTRACT
We evaluated fresh vegetables for residues of 18 pesticides with different chemical structures, including organochlorine pesticides, organophosphorus pesticides, carbamate pesticides, and pyrethroid pesticides and estimated that the potential health risks for consumers. A total of 313 samples were collected from 12 kinds of vegetables in Changchun, the capital of Jilin Province, People's Republic of China. Pesticide residues were analyzed by gas chromatography and mass spectrometry, and the curves were highly linear at 0.01 to 1.00 μg/mL (R2 ≥ 0.99). The mean recovery rate of the pesticides was 62 to 110% (relative standard deviation of <5%). The limit of detection was 0.0001 to 0.0167 mg/kg, the limit of quantification was 0.0002 to 0.0556 mg/kg, and the overall detection rate was 28.43%. The prevalence of pesticides and of samples above the standard limit were highest in celery, the prevalence of pesticides was lowest in potatoes, and the prevalence of samples above the standard limit was lowest in cucumber. Three of the 18 pesticides were not detected: omethoate, chlorpyrifos, and fenvalerate. Among the 15 pesticides detected, the maximum risk factor of six (carbofuran, omethoate, phorate, dicofol, dimethoate, and dichlorvos) is >1, indicating possible harm to human health. Residues of a single pesticide may not adversely affect a person's health, but multiple pesticide residues could present a health risk.
Topics: China; Food Contamination; Humans; Pesticide Residues; Pesticides; Vegetables
PubMed: 33108463
DOI: 10.4315/JFP-20-236 -
Plant Disease Sep 2020Late and early leaf spot are caused by and , respectively, and are damaging diseases of peanut ( L.) capable of defoliation and yield loss. Management of these diseases...
Late and early leaf spot are caused by and , respectively, and are damaging diseases of peanut ( L.) capable of defoliation and yield loss. Management of these diseases is most effective through the integration of tactics that reduce starting inoculum and prevent infection. The insecticide phorate was first registered in 1959 and has been used in peanut production for decades in-furrow at planting to suppress thrips. Phorate further provides significant suppression of infection beyond suppression of its thrips vector alone by activating defense-related responses in the peanut plant. From six experiments conducted from 2017 to 2019 in Blackville, SC, Reddick, FL, and Quincy, FL, significantly less leaf spot defoliation was exhibited on peanuts treated with phorate in-furrow at planting (26%) compared with nontreated checks (48%). In-season fungicides were excluded from five of the experiments, whereas the 2018 Quincy, FL, experiment included eight applications on a 15-day interval. Across individual experiments, significant suppression of defoliation caused by late leaf spot was observed from 64 to 147 days after planting. Although more variable within location-years, pod yield following phorate treatment was overall significantly greater than for nontreated peanut (2,330 compared with 2,030 kg/ha; = 0.0794). The consistent defoliation suppression potential was estimated to confer an average potential net economic yield savings of $90 to $120 per hectare under analogous leaf spot defoliation. To our knowledge, these are the first data in the 61 years since its registration demonstrating significant suppression of leaf spot on peanut following application of phorate in-furrow at planting. Results support phorate use in peanut as an effective and economical tactic to incorporate to manage late and early leaf spot infections and development of fungicide resistance.
PubMed: 32900292
DOI: 10.1094/PDIS-03-20-0547-RE -
Environmental Research Oct 2020Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been...
Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been the focus of intensive debate and research. Specifically, exposure through contaminated pollen and nectar is considered pivotal, as it presents the highest risk of PPP exposure across all bee species. However, the actual risk that multiple PPP residues might pose to non-target species is difficult to assess due to the lack of clear evidence of their actual concentrations. To consolidate the existing knowledge of field-realistic residues detected in pollen and nectar directly collected from plants, we performed a systematic literature review of studies over the past 50 years (1968-2018). We found that pollen was the matrix most frequently evaluated and, of the compounds investigated, the majority were detected in pollen samples. Although the overall most studied category of PPPs were the neonicotinoid insecticides, the compounds with the highest median concentrations of residues in pollen were: the broad spectrum carbamate carbofuran (1400 ng/g), the fungicide and nematicide iprodione (524 ng/g), and the organophosphate insecticide dimethoate (500 ng/g). In nectar, the highest median concentration of PPP residues detected were dimethoate (1595 ng/g), chlorothalonil (76 ng/g), and the insecticide phorate (53.5 ng/g). Strong positive correlation was observed between neonicotinoid residues in pollen and nectar of cultivated plant species. The maximum concentrations of several compounds detected in nectar and pollen were estimated to exceed the LD for honey bees, bumble bees and four solitary bee species, by several orders of magnitude. However, there is a paucity of information for the biggest part of the world and there is an urgent need to expand the range of compounds evaluated in PPP studies.
Topics: Animals; Bees; Insecticides; Neonicotinoids; Pesticide Residues; Plant Nectar; Pollen; Pollination
PubMed: 32795671
DOI: 10.1016/j.envres.2020.109873 -
Current Microbiology Oct 2020Brevibacterium frigoritolerans, a strain quite potential use in environmental pollution, is also able to degrade the pesticide phorate. Here, we report a strain isolated...
Brevibacterium frigoritolerans, a strain quite potential use in environmental pollution, is also able to degrade the pesticide phorate. Here, we report a strain isolated from radioactive soil in the Xinjiang Uygur Autonomous Region of China. The genome of strain GD44 encompasses 5,471,331 base pairs with a GC content of 40.42%. The sequence was assembled into 1985 open reading frames (ORFs) encoding 5053 proteins. Sequence analysis identified the genes encoding enzymes related to the degradation of organophosphorus compounds such as esterase, phosphotransferase, C-P lyase, and alkaline phosphatase. The nitrate reductase gene was also found in GD44, which was associated with biosynthesis of silver nanoparticles used for bacteriostat. In addition, Antibiotic Resistance Ontology (ARO) genes accounted for 10.6%, including the vancomycin resistance gene cluster. Therefore, the whole-genome sequence of B. frigoritolerans GD44 will be beneficial for identifying and analyzing genes utilized for soil remediation and antibacterial agent, which will provide genetic evaluation for potential application in the future.
Topics: Bacillus; Bacterial Proteins; China; Enzymes; Genome, Bacterial; Metal Nanoparticles; Organophosphates; Silver; Soil Microbiology; Soil Pollutants, Radioactive
PubMed: 32651608
DOI: 10.1007/s00284-020-02037-9 -
Journal of Hazardous Materials Jan 2021Contaminated sites from pesticide industry have attracted global concern due to the characteristics of organic pollution with high concentrations and complete loss of...
Contaminated sites from pesticide industry have attracted global concern due to the characteristics of organic pollution with high concentrations and complete loss of habitat conditions. Remediation of organophosphorus pesticide polluted soil using microwave-activated persulfate (MW/PS) oxidation was investigated in this study, with parathion as the representative pesticide. Approximately 90 % of parathion was degraded after 90 min of MW/PS oxidation treatment, which was superior to those by single PS or MW treatment. Relatively greater performances for parathion degradation were obtained in a relatively larger PS dosage, higher microwave temperature, and lower organic matter content. Appropriate soil moisture favored parathion degradation in soil. SO, OH, O, and O generated in the MW/PS system all contributed to parathion degradation. Multiple spectroscopy analyses indicated that PO and PS bonds in parathion were destroyed after MW/PS oxidation, accompanied by generation of hydroxylated and carbonylated byproducts. The soil safety after parathion degradation was assessed via model prediction. Furthermore, MW/PS oxidation also exhibited great performance for degradation of other organophosphorus pesticides, including ethion, phorate, and terbufos.
PubMed: 32645541
DOI: 10.1016/j.jhazmat.2020.123361 -
Pest Management Science Dec 2020Resistance to the dinitroaniline herbicide trifluralin in Lolium rigidum (annual ryegrass) often is mediated by the enhanced capacity to metabolize the herbicide to less...
BACKGROUND
Resistance to the dinitroaniline herbicide trifluralin in Lolium rigidum (annual ryegrass) often is mediated by the enhanced capacity to metabolize the herbicide to less toxic polar conjugates and/or by functionally recessive target-site mutations in α-tubulin.
RESULTS
In two L. rigidum populations possessing enhanced trifluralin metabolism, resistance was largely reversed by recurrent selection with the thiocarbamate herbicide prosulfocarb (i.e. plant survival was two- to >20-fold lower). Their ability to metabolize trifluralin was significantly decreased (by ≈2.3-fold) following recurrent prosulfocarb selection, to levels comparable to those observed in susceptible plants or when trifluralin metabolism was inhibited by treatment with the insecticide phorate.
CONCLUSIONS
This study provides evidence that trait(s) enabling efficient trifluralin metabolism in L. rigidum are purged from the population under prosulfocarb recurrent selection. The level of trifluralin metabolism in vitro and its inhibition caused by phorate action on trifluralin-metabolizing enzyme(s) is equivalent to the effect produced by prosulfocarb selection. The hypothetical link between the two phenomena is that the putative monooxygenase(s) conferring trifluralin metabolic resistance also mediate the activation of prosulfocarb to its toxic sulfoxide. Thus, we speculate that survival to prosulfocarb via a lack of metabolic herbicide activation, and survival to trifluralin conferred by enhanced herbicide metabolism, are mutually exclusive. These findings not only open up a new research direction in terms of the interaction between different herbicide resistance mechanisms in L. rigidum, but also offer strategies for immediate management of the population dynamics of metabolism-based resistance in the field. © 2020 Society of Chemical Industry.
Topics: Carbamates; Herbicide Resistance; Herbicides; Lolium; Trifluralin
PubMed: 32638493
DOI: 10.1002/ps.5993