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Chemosphere Jun 2024This prospective work focuses on the use of two different gaseous oxidants (chlorine dioxide and ozone) to remediate soil polluted with methomyl in two different...
This prospective work focuses on the use of two different gaseous oxidants (chlorine dioxide and ozone) to remediate soil polluted with methomyl in two different applications: ex-situ and in-situ. In the first, the soil washing is integrated with the bubbling of the oxidant, while in the second, the gas was introduced by a perforated pipe located sub-superficially. Regarding the soil washing treatment, results demonstrate that direct use of ozone is not very efficient, although an important improvement is obtained following activation with hydrogen peroxide or UV light. In contrast, chlorine dioxide exhibited complete methomyl depletion from the soil, although with higher energy consumption and technical complexity compared to ozone. The direct dosing of the gaseous oxidants in perforated pipes is effective, achieving methomyl removals of 7.8 % and 9.2 % using ozone and chlorine dioxide, respectively. In these cases, soil conditions are not significantly modified, which becomes an important advantage of the technology as compared with other electrochemically assisted soil remediation process, in which large regions of the treated soil are affected by important changes in the pH or by depletion of ions. This lower impact makes these novel technologies more promising for further evaluations.
PubMed: 38906193
DOI: 10.1016/j.chemosphere.2024.142653 -
Pesticide Biochemistry and Physiology Jun 2024Sitobion miscanthi is a destructive wheat pest responsible for significant wheat yield losses. Pirimicarb, one of the most important representatives of N,...
Sitobion miscanthi is a destructive wheat pest responsible for significant wheat yield losses. Pirimicarb, one of the most important representatives of N, N-dimethylcarbamate insecticides, is widely used to control wheat aphids. In present work, heterozygous S431F mutation of acetylcholinesterase 1 (AChE1) was identified and verified in three pirimicarb-resistant S. miscanthi populations (two field populations (HA and HS, >955.8-fold) and one lab-selected population (PirR, 486.1-fold)), which has not been reported in S. miscanthi yet. The molecular docking results revealed that AChE1 containing the S431F mutation of S. miscanthi (SmAChE1) showed higher free binding energy to three insecticides (pirimicarb, omethoate, and methomyl) than wild-type AChE1 of S. miscanthi (SmAChE1). Enzyme kinetic and inhibition experiments showed that the recombinant SmAChE1 was more insensitive to pirimicarb and omethoate than the recombinant SmAChE1. Furthermore, two overexpression P450 genes (CYP6K1 and CYP6A14) associated with pirimicarb resistance of S. miscanthi were verified by RNAi. These results suggested both target alteration and enhanced metabolism contributed to high pirimicarb resistance of S. miscanthi in the field and laboratory. These findings lay a foundation for further elucidating the mechanism of pirimicarb resistance in S. miscanthi, and have important implications for the resistance management of S. miscanthi control.
Topics: Acetylcholinesterase; Animals; Insecticide Resistance; Aphids; Insecticides; Carbamates; Cytochrome P-450 Enzyme System; Mutation; Pyrimidines; Molecular Docking Simulation; Triticum; Dimethoate
PubMed: 38879339
DOI: 10.1016/j.pestbp.2024.105957 -
Pest Management Science Jun 2024The corn leafhopper, Dalbulus maidis, is an important pest in Brazil. While chemical control has traditionally been the cornerstone for managing this pest, field control...
BACKGROUND
The corn leafhopper, Dalbulus maidis, is an important pest in Brazil. While chemical control has traditionally been the cornerstone for managing this pest, field control failures have been reported for some insecticides. To understand if these failures are due to resistance, we evaluated the susceptibility of 11 field-collected populations of D. maidis to major insecticides during the 2021-2022 crop seasons in Brazil using concentration-mortality bioassays. Additionally, we employed diagnostic concentration bioassays and foliar sprays at label-recommended rates in 8-10 populations collected during the 2022-2023 crop seasons.
RESULTS
High susceptibility to methomyl, carbosulfan and acephate was observed on concentration-mortality bioassays across all populations tested with resistance ratio (RR) based on LC <10-fold, except for one population from Bahia State that exhibited reduced susceptibility to methomyl (RR = 17.5). On the other hand, all populations exhibited reduced susceptibility to bifenthrin, acetamiprid, and imidacloprid, with RR ranging from 90 to 2000-fold. This reduced susceptibility to neonicotinoid and pyrethroid insecticides was further confirmed at diagnostic concentrations based on LC of the susceptible strain, with survival rates >20% and in foliar sprays with mortality rates <80%. Most populations exposed to acephate and carbosulfan exhibited low survival rates at diagnostic concentrations (<5%) and high mortality rates in foliar sprays (>80%).
CONCLUSIONS
The reduced susceptibility to pyrethroid and neonicotinoid insecticides likely explain the field failures in controlling D. maidis populations in Brazil. This study represents the first large-scale susceptibility monitoring of D. maidis to insecticides, and the results will contribute to decision-making regarding the management of this pest. © 2024 Society of Chemical Industry.
PubMed: 38868923
DOI: 10.1002/ps.8237 -
Scientific Reports Jun 2024This study aimed to investigate carbamate pesticide residues in different varieties of date palm fruits in the UAE, utilizing UHPLC-MS/MS. For sample preparation and...
This study aimed to investigate carbamate pesticide residues in different varieties of date palm fruits in the UAE, utilizing UHPLC-MS/MS. For sample preparation and clean-up, the efficiency and performance of different QuEChERS dispersive solid-phase extraction kits were compared. Precision and recovery were assessed at 10 μg kg for the three kits, revealing that Kit 2 demonstrated the best performance. The selected QuEChERS method was validated to detect 14 carbamate residues in 55 date samples. The method exhibited strong linearity with R > 0.999 and low LOD (0.01-0.005 μg kg) and LOQ (0.003-0.04 μg kg). Excellent accuracy (recovery: 88-106%) and precision (RSD: 1-11%) were observed, with negligible matrix effect (- 4.98-13.26%). All samples contained at least one carbamate residue. While most detected residues were below their MRLs, carbosulfan was found in 21 samples, propoxur in 2 samples, and carbofuran in 1 sample above their MRLs. The hazard index (HI) was calculated for carbosulfan, phenmedipham, carbaryl, propoxur, carbofuran, and methomyl to assess potential health risks for date consumers. All HI values were below the safety limit of 1.0, indicating that the consumption of dates does not pose a non-carcinogenic health risk for adults and children.
Topics: Phoeniceae; Pesticide Residues; Chromatography, High Pressure Liquid; Tandem Mass Spectrometry; Carbamates; Fruit; Humans; Risk Assessment; Solid Phase Extraction; Food Contamination
PubMed: 38844596
DOI: 10.1038/s41598-024-63704-6 -
Food Additives & Contaminants. Part B,... Jun 2024This study evaluated the presence of the three pesticides methomyl (MET), carbendazim (CBZ) and chlorpyrifos-ethyl (CPE), as well as the degradation product of CPE...
This study evaluated the presence of the three pesticides methomyl (MET), carbendazim (CBZ) and chlorpyrifos-ethyl (CPE), as well as the degradation product of CPE (3,5,6-trichloro-2-pyridinol; TCP), in 44 honey samples from all 12 regions of Morocco. With a validated HPLC-UV method occurrence frequencies of 63.6% for MET, 54.5% for CBZ, 95.1% for CPE and 34.1% for TCP were obtained, even at concentrations higher than the maximum residue limits for MET, CPE and TCP. Based on the predominant pesticide, principal component analysis separated sampling regions into three groups. Risk assessment indicated that ingestion of these pesticides, alone or in combination, in honey did not pose a risk to consumers (HQ and HI < 1).
PubMed: 38835106
DOI: 10.1080/19393210.2024.2362981 -
Pest Management Science May 2024Chrysodeixis includens (Walker) and Rachiplusia nu (Guenée) are major Plusiinae pests of soybean in the Southern Cone region of South America. In recent decades, C....
Characterizing the differential susceptibility and resistance to insecticides in populations of Chrysodeixis includens and Rachiplusia nu (Lepidoptera: Noctuidae) in Brazil.
BACKGROUND
Chrysodeixis includens (Walker) and Rachiplusia nu (Guenée) are major Plusiinae pests of soybean in the Southern Cone region of South America. In recent decades, C. includens was the main defoliator of soybean in Brazil, but from 2021 onwards, R. nu emerged as an important soybean pest in various regions of the country. Here, we characterize the differential susceptibility and resistance to insecticides in these Plusiinae pests from two soybean regions of Brazil.
RESULTS
Except for spinetoram and chlorfenapyr (comparable lethality against both species) and a Bt-based biopesticide (more lethal for C. includens), the tested insecticides showed higher lethality against R. nu than against C. includens, but populations of the same species, even separated by long distances, presented similar resistance levels. For both species, the 90% lethal concentration (LC) values of most insecticides were higher than the field-recommended dose. Nevertheless, the field-recommended doses of spinetoram, metaflumizone, emamectin benzoate, cyclaniliprole and chlorfenapyr showed comparable control efficacy against both species, whereas indoxacarb, chlorantraniliprole, flubendiamide, teflubenzuron and chlorfluazuron were more lethal for R. nu, and methoxyfenozide and the Bt-based insecticide were more lethal for C. includens. Thiodicarb, methomyl and lambda-cyhalothrin showed low lethality against both species.
CONCLUSIONS
Large interspecific differences in the susceptibility to insecticides was found in major Plusiinae pests of soybean in Brazil. Furthermore, variations in susceptibility to insecticides occurred consistently among species and populations, regardless of the collection site and thus despite unequal temporal and spatial exposure to insecticides. These results demonstrate that accurate species identification is essential for effective control of Plusiinae in soybean. © 2024 Society of Chemical Industry.
PubMed: 38801197
DOI: 10.1002/ps.8197 -
Journal of Pharmaceutical and... Aug 2024Pesticides play an important role in forensic toxicology and are usually classified as a single class of chemicals. Despite their commonly perceived unity, pesticides...
Development and validation of a multi-substance method for routine analysis of pesticides in post-mortem samples by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.
Pesticides play an important role in forensic toxicology and are usually classified as a single class of chemicals. Despite their commonly perceived unity, pesticides encompass a spectrum of compounds, including organophosphates, carbamates, pyrethroids or organochlorines, among others, each with varying degrees of toxicity. Pesticide analysis in post-mortem samples can be difficult due to the complexity of the samples and to the high toxicity of these compounds. The aim of this study was to develop and validate an easy to use, sensitive, and robust method, using ultra-performance liquid chromatography-tandem mass spectrometry to be incorporated in the routine flow for pesticide analysis in post-mortem blood samples. Described herein is a streamlined, expeditious, yet highly efficient method facilitating the screening, qualitative assessment, and quantitative confirmation of 15 pesticides, including acetamiprid, azinphos-ethyl, bendiocarb, carbofuran, chlorfenvinphos, dimethoate, imidaclopride, malathion, methiocarb, methomyl, parathion, pirimicarb, strychnine, tetrachlorvinphos, and thiacloprid in post-mortem blood, recognizing the pivotal role blood plays in forensic investigations. The developed method was linear from 10 to 200 ng/mL; limits of detection were between 1 and 10 ng/mL, depending on the compound; it was successfully evaluated a dilution ratio of 1-2, 5 and 10; and 8 substances showed maximum stability for the time interval studied. This UHPLC-MS/MS method is useful and a powerful tool in a toxicology lab because it is fast, simple, effective, and trustworthy. The results of this validation highlight the robustness of the analytical method, providing a valuable tool for the accurate and sensitive detection of pesticides in post-mortem blood. Poised for routine implementation, this method has already found success in suspected intoxication cases, promising to elevate the standards of forensic pesticide analysis.
Topics: Tandem Mass Spectrometry; Chromatography, High Pressure Liquid; Humans; Pesticides; Forensic Toxicology; Reproducibility of Results; Autopsy; Limit of Detection
PubMed: 38701535
DOI: 10.1016/j.jpba.2024.116176 -
Industrial & Engineering Chemistry... Apr 2024This work focuses on the comparison of the performance of direct electrochemical oxidation with indirect electrolysis mediated by gaseous oxidants in the treatment of...
This work focuses on the comparison of the performance of direct electrochemical oxidation with indirect electrolysis mediated by gaseous oxidants in the treatment of diluted wastewater. To do this, energy consumptions of the electrolysis using mixed metal oxide (MMO) electrodes are compared with those required for the production and use of chlorine dioxide in the degradation of methomyl contained in aqueous solutions. Results demonstrate the feasibility of the mediated oxidation process and that this process is competitive with direct oxidation. The oxidants are produced under optimized conditions using the same anodic material applied for the direct degradation of organics, thus avoiding efficiency losses associated with mass transfer limitations in the degradation of dilute organic solutions. Thus, using the ClO gaseous oxidant, a concentration of 0.1 mM of methomyl from a solution containing 500 mL is completely removed with an energy consumption as low as 50 Wh. The application of the same energy to a direct electrolytic process for treating the same wastewater can only reach less than half of this removal. These findings may have a very important application in the use of electrochemical technology to achieve the remediation of persistent pollutants in wastewater, where their low concentrations typically make direct processes very inefficient.
PubMed: 38660619
DOI: 10.1021/acs.iecr.3c03265 -
Journal For Immunotherapy of Cancer Apr 2024Combining immune checkpoint inhibitors (ICIs) with chemotherapy has become a standard treatment for patients with non-small cell lung cancer (NSCLC) lacking driver gene...
BACKGROUND
Combining immune checkpoint inhibitors (ICIs) with chemotherapy has become a standard treatment for patients with non-small cell lung cancer (NSCLC) lacking driver gene mutations. Reliable biomarkers are essential for predicting treatment outcomes. Emerging evidence from various cancers suggests that early assessment of serum metabolites could serve as valuable biomarkers for predicting outcomes. This study aims to identify metabolites linked to treatment outcomes in patients with advanced NSCLC undergoing first-line or second-line therapy with programmed cell death 1 (PD-1) inhibitors plus chemotherapy.
METHOD
200 patients with advanced NSCLC receiving either first-line or second-line PD-1 inhibitor plus chemotherapy, and 50 patients undergoing first-line chemotherapy were enrolled in this study. The 200 patients receiving combination therapy were divided into a Discovery set (n=50) and a Validation set (n=150). These sets were further categorized into respond and non-respond groups based on progression-free survival PFS criteria (PFS≥12 and PFS<12 months). Serum samples were collected from all patients before treatment initiation for untargeted metabolomics analysis, with the goal of identifying and validating biomarkers that can predict the efficacy of immunotherapy plus chemotherapy. Additionally, the validated metabolites were grouped into high and low categories based on their medians, and their relationship with PFS was analyzed using Cox regression models in patients receiving combination therapy.
RESULTS
After the impact of chemotherapy was accounted for, two significant differential metabolites were identified in both the Discovery and Validation sets: N-(3-Indolylacetyl)-L-alanine and methomyl (VIP>1 and p<0.05). Notably, upregulation of both metabolites was observed in the group with a poorer prognosis. In the univariate analysis of PFS, lower levels of N-(3-Indolylacetyl)-L-alanine were associated with longer PFS (HR=0.59, 95% CI, 0.41 to 0.84, p=0.003), and a prolonged PFS was also indicated by lower levels of methomyl (HR=0.67, 95% CI, 0.47 to 0.96, p=0.029). In multivariate analyses of PFS, lower levels of N-(3-Indolylacetyl)-L-alanine were significantly associated with a longer PFS (HR=0.60, 95% CI, 0.37 to 0.98, p=0.041).
CONCLUSION
Improved outcomes were associated with lower levels of N-(3-Indolylacetyl)-L-alanine in patients with stage IIIB-IV NSCLC lacking driver gene mutations, who underwent first-line or second-line therapy with PD-1 inhibitors combined with chemotherapy. Further exploration of the potential predictive value of pretreatment detection of N-(3-Indolylacetyl)-L-alanine in peripheral blood for the efficacy of combination therapy is warranted.
STATEMENT
The combination of ICIs and chemotherapy has established itself as the new standard of care for first-line or second-line treatment in patients with advanced NSCLC lacking oncogenic driver alterations. Therefore, identifying biomarkers that can predict the efficacy and prognosis of immunotherapy plus chemotherapy is of paramount importance. Currently, the only validated predictive biomarker is programmed cell death ligand-1 (PD-L1), but its predictive value is not absolute. Our study suggests that the detection of N-(3-Indolylacetyl)-L-alanine in patient serum with untargeted metabolomics prior to combined therapy may predict the efficacy of treatment. Compared with detecting PD-L1 expression, the advantage of our biomarker is that it is more convenient, more dynamic, and seems to work synergistically with PD-L1 expression.
Topics: Humans; B7-H1 Antigen; Biomarkers; Carcinoma, Non-Small-Cell Lung; Immune Checkpoint Inhibitors; Lung Neoplasms; Metabolomics; Antineoplastic Combined Chemotherapy Protocols
PubMed: 38641349
DOI: 10.1136/jitc-2023-008190 -
Neurotoxicology May 2024Exposure to pesticides, such as carbamates, organophosphates, organochlorines and pyrethroids, has been linked to various health problems, including neurotoxicity....
Exposure to pesticides, such as carbamates, organophosphates, organochlorines and pyrethroids, has been linked to various health problems, including neurotoxicity. Although most in vivo studies use only male rodents, some studies have shown in vivo sex-specific effects after acute exposure. Since in vivo studies are costly and require a large number of animals, in vitro assays that take sex-specific effects into account are urgently needed. We therefore assessed the acute effects of exposure to different carbamates (methomyl, aldicarb and carbaryl), organophosphates (chlorpyrifos (CPF), chlorpyrifos-oxon (CPO) and 3,5,6-trichloropyridinol), organochlorines (endosulfan, dieldrin and lindane) and pyrethroids (permethrin, alpha-cypermethrin and 3-phenoxy-benzoic acid (3-PBA)) on neuronal network function in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings. Our results indicate that exposure to the carbamate carbaryl and the organophosphates CPF and CPO decreased neuronal activity, with CPO being the most potent. Notably, (network) burst patterns differed between CPF and CPO, with CPO inducing fewer, but more intense (network) bursts. Exposure to low micromolar levels of endosulfan induced a hyperexcitation, most likely due to the antagonistic effects on GABA receptors. Interestingly, females were more sensitive to endosulfan than males. Exposure to dieldrin and lindane also increased neuronal activity, albeit less than endosulfan and without sex-specific effects. Exposure to type I pyrethroid permethrin increased neuronal activity, while exposure to type II pyrethroid alpha-cypermethrin strongly decreased neuronal activity. The increase seen after permethrin exposure was more pronounced in males than in females. Together, these results show that acute exposure to different classes of pesticides exerts differential effects on neuronal activity. Moreover, it shows that MEA recordings are suited to detect sex-specific neurotoxic effects in vitro.
Topics: Animals; Insecticides; Neurons; Female; Male; Cerebral Cortex; Rats; Cells, Cultured; Action Potentials; Dose-Response Relationship, Drug; Microelectrodes; Rats, Wistar
PubMed: 38599286
DOI: 10.1016/j.neuro.2024.04.004