Guizhou Province has historically been a region severely affected by malaria in China. For decades, vector control has served as a cornerstone of national efforts to control and eliminate malaria. However, the efficacy of this strategy is largely challenged by the development of insecticide resistance. In the present study, the resistance status to organophosphates (OPs) and carbamates (CBs) ofAnopheles sinensisfield populations across Guizhou Province was investigated with a primary focus on elucidating the underlying mechanisms. From 2017 to 2024, mosquitoes were collected intermittently using mosquito-killing lamps across Guizhou Province.An. sinensisspecimens were identified using morphological and molecular methods. Subsequently, we genotyped theace-1gene via PCR and measured acetylcholinesterase1 (AChE1) residual activity using biochemical assays. Whole-genome sequencing of individual mosquitoes was performed using Illumina sequencing, and the copy number of theace-1gene was quantified by standard genomic DNA quantitative PCR. Two independent-sample t-test and a chi-squared test had been used in this study. FemaleAn. sinensiswere collected from 12 field populations across Guizhou Province. Following species identification, point mutations in theace-1gene were detected in 551 mosquito samples. Only one point mutation, G119S, was identified across all populations, with the frequency ofthe ace-1mutant genotypes (119GS and 119SS) exceeding 66% in 11 out of the 12 populations. Heterozygotes were the predominant genotype. The AChE1 activity was not inhibited by propoxur in 10 populations. A significant departure from Hardy-Weinberg equilibrium was observed in 6 of the 12 populations, indicating an excess of heterozygotes in these populations. Notably, heterogeneous duplication of theace-1gene inAn. sinensiswas detected for the first time through genomic scanning andace-1copy number quantification. Resistance to OPs and CBs is widespread inAn. sinensispopulations across Guizhou Province. Both heterogeneous duplication and point mutation of theace-1gene inAn. sinensislikely contribute to resistance to OPs and CBs. These findings highlight the necessity of monitoring duplicated resistance alleles in natural populations to formulate region-specific resistance management strategies.

In this work, the capability of the 1H nuclear Overhauser effect (NOE) pumping NMR technique was applied to elucidate the atomic-level binding interaction between the bovine serum albumin (BSA) and four toxic compounds: amiton, dimethoate, carbofuran, and aminostigmine. With the aid of 1H NOE pumping experiments, we were able to highlight ligand binding epitopes for the studied compounds and provide prefatory data for the ligand affinity with BSA via dissociation constant values (KD). In addition, we demonstrate that the 1H NOE pumping technique is suitable for the ligand competition studies solely using one NMR sample and that the technique is a simple and straightforward method capable of revealing important parameters that are used typically to define ligand-albumin interaction at the atomic level. We believe the novel precursory results herein provide important and experimentally driven data for the BSA interaction, especially for carbamate-based molecules, where the existing literature is fairly limited. Based on the preliminary experimental results, amiton and aminostigmine showed stronger binding to BSA based on NOE pumping data compared with dimethoate and carbofuran, although the obtained KD values were observed within a similar range. Our results present the first comparable study between the organophosphorus (OP) and the carbamate (CM) toxic compounds with BSA via NMR spectroscopy only. Furthermore, the efficacy of the 1H NOE pumping technique provided evidence that the organophosphorus and carbamate compounds bind to a common epitope site on BSA.

Chamber validation study of simultaneous collection and analysis of aromatic diisocyanates and the corresponding diamines using the ASSET-ICA sampler.

Prenatal exposure to agricultural pesticide applications and gestational diabetes mellitus in the Az-PEARS population-based study (2014-2020).

Fabrication of montmorillonite composite alginate beads for micro-solid phase extraction of carbamate residues prior to their determination by ultra performance liquid chromatography-photodiode array detector.

MOF-enabled magnetic-fluorescent sensors for on-site organophosphorus/carbamate pesticide detection in fruits and vegetables.

Recognition of organophosphate and carbamate pesticides by cholinesterase sensor arrays on the basis of enzymes from different organisms

The widespread use of organophosphate (OP) and carbamate (CM) pesticides requires efficient and cost-effective detection methods. This study introduces a micro-electrometric method using cricket cholinesterase (ChE) to detect OP and CM residues, providing a rapid and economical alternative to conventional chromatographic techniques. The parameters of the method, including the substrate concentration, incubation temperature, and incubation time, were optimized. By leveraging the sensitivity of cricket ChE to OP and CM inhibition, this approach translates enzyme inhibition into an electrical signal to quantify pesticide levels, achieving an impressive limit of detection (LOD) from 0.036 to 0.086 parts per million (ppm). This method demonstrated reproducibility and stability, making it suitable for field applications and on-site testing across various environmental matrices. This research represents a significant advancement in pesticide residue analysis with potential applications in the development of portable biosensor devices for real-time environmental monitoring and public health protection.

Organophosphates (OPs) and carbamates (CMs) play a vital role in Thai agriculture, public health, and pest control. However, their detection presents challenges due to expensive methods requiring specialized expertise. Addressing this gap, our study introduces an innovative, cost-effective method for detecting OPs and CMs in Thailand. We utilized the test kit by using magnetic particles coated with esterase enzymes from honey bee heads combined with a colorimetric approach. The developed test kit shows low limits of detection (LODs) at 0.001 mg/L of dichlorvos (OPs) and 0.004 mg/L for carbaryl (CMs). The efficiency of the developed test kits in comparison with the standard technique of gas chromatography with flame photometry detection (GC-FPD) shows a comparable result in fruit and vegetable residue analysis. This developed test kit proposes a cost-effective OPs and CMs analysis test kit for Thailand, promising expense reduction and simplified verification processes. Its applicability to fruits and vegetables signifies practicality in agriculture, marking a significant advancement in accessible and efficient pesticide residue monitoring. Despite challenges in pesticide use, our method holds promise for improving safety and efficiency in Thai pesticide management.Graphical

Causal inference and mechanism for unraveling the removal of four pesticides from lettuce (Lactuca sativa L.) via ultrasonic processing and various immersion solutions

Elevated accumulation and distinct migration patterns of neonicotinoids compared to traditional insecticides in South China typical orchard

An amino acid ionic liquid-based biphasic solvent with low viscosity, small rich-phase volume, and high CO2 loading rate for efficient CO2 capture

One-step detection of pesticide residues in vegetables using an inkjet printing-based test card

BackgroundArmenia is considered particularly vulnerable to life-threatening vector-borne diseases (VBDs) including malaria, West Nile virus disease and leishmaniasis. However, information relevant for the control of the vectors of these diseases, such as their insecticide resistance profile, is scarce. The present study was conducted to provide the first evidence on insecticide resistance mechanisms circulating in major mosquito and sand fly populations in Armenia.MethodsSampling sites were targeted based mainly on previous historical records of VBD occurrences in humans and vertebrate hosts. Initially, molecular species identification on the collected vector samples was performed. Subsequently, molecular diagnostic assays [polymerase chain reaction (PCR), Sanger sequencing, PCR-restriction fragment length polymorphism (RFLP), quantitative PCR (qPCR)] were performed to profile for major insecticide resistance mechanisms, i.e. target site insensitivity in voltage-gated sodium channel (vgsc) associated with pyrethroid resistance, acetylcholinesterase (ace-1) target site mutations linked to organophosphate (OP) and carbamate (CRB) resistance, chitin synthase (chs-1) target site mutations associated with diflubenzuron (DFB) resistance and gene amplification of carboxylesterases (CCEs) associated with resistance to the OP temephos.ResultsAnopheles mosquitoes were principally represented by Anopheles sacharovi, a well-known malaria vector in Armenia, which showed no signs of resistance mechanisms. Contrarily, the knockdown resistance (kdr) mutations V1016G and L1014F/C in the vgsc gene were detected in the arboviral mosquito vectors Aedes albopictus and Culex pipiens, respectively. The kdr mutation L1014S was also detected in the sand fly, vectors of leishmaniasis, Phlebotomus papatasi and P. tobbi, whereas no mutations were found in the remaining collected sand fly species, P. sergenti, P. perfiliewi and P. caucasicus.ConclusionsThis is the first study to report on molecular mechanisms of insecticide resistance circulating in major mosquito and sand fly disease vectors in Armenia and highlights the need for the establishment of systematic resistance monitoring practices for the implementation of evidence-based control applications.Graphical

Highly efficient functionalization of hydroxypropyl cellulose with glucuronic acid through click chemistry under microwave irradiation as potential biomaterial with therapeutic properties

Dual-use ionization source for direct and sensitive detection of trace carbamates residue

Molecular, biochemical, and toxicological characterization of two acetylcholinesterases from the Western flower thrips, Frankliniella occidentalis

The reaction of pesticides with the OH radical, is the most dominant annihilation reaction ofthe atmosphere. Phosmet, Azamethiphos, Coumaphos and Temephos were used as organophosphorouspesticides, and Methiocarb, Carbofuran and Pirimicarb compounds were used as carbamate pesticideswith the aim of investigating the kinetics of the reactions of Organophosphorous (OPs) and Carbamate(CBs) Pesticides with the OH radicals. In aqueous TiO2 suspensions, the degradation reactions viaphotocatalytic-effect of the seven pesticides selected as pollutants were analysed, and the impact of theinitial concentration was calculated. All experiments were conducted in the same photoreactor and underthe same conditions as three repetitions. The optimum amount of photocatalyst for the studied pesticidewas determined and TiO2 concentration for all experiments were taken as 0.2 g/100 mL. Considering thatorganic pollutants are present in water in trace amount, the initial concentrations for all organiccompounds were added so as to be1.0x10-4 molxL-1, into the suspensions and the solution containing theorganic pollutant. In this study, degradation speed of pesticides were determined experimentally, and thefastest degrading pesticide was tried to be found out.

Nowadays, pyrethroid (Py) insecticides are commonly used against household insect pests and housefly. The combination of Py and organophosphates (OP) are also utilized to combat these insects. The resistance status of Iranian housefly populations to them and carbamate (CB) insecticides is uncertain. This study investigates the presence of acetylcholinesterase (AChE) mutations related to the resistance of Musca domestica to OP and/or CB insecticides in Northwestern Iran. Nucleotides 1041–1776, based on their positions in the ACE gene of aabys strain, were amplified and sequenced in houseflies collected from West Azerbaijan, Gilan, and Ardebil Provinces, Iran. Among 12 single-nucleotide polymorphisms detected, 3 mismatches were found at nucleotides 1174 (T/A, G), 1473 (G/T, C), and 1668 (T/A), leading to amino acid substitutions in V260L, G342A/V, and F407Y positions with various combinations. Genotyping results showed that 85% of specimens had at least one of these substitutions. In addition, the Iranian housefly population was composed of 5 insensitive and sensitive alleles. For the first time, the current study reports the presence of V260L, G342A, G342V, and F407Y substitutions in M. domestica specimens collected from Northwestern Iran. The selection of multiple alleles in field populations might be due to the application of various pesticides/insecticides during extended periods in the region. These molecular levels signify the presence of control problems in the area and the need for developing effective control strategies for such populations.

The DNA photocleavage effect of halogenated O-carbamoyl derivatives of 4-MeO-benzamidoxime under UVB and UVA irradiation was studied in order to identify the nature, position, and number of halogens on the carbamoyl moiety that ensure photoactivity. F, Cl, and Br-phenyl carbamate esters (PCME) exhibited activity with the p-Cl-phenyl derivative to show excellent photocleavage against pBR322 plasmid DNA. m-Cl-PCME has diminished activity, whereas the presence of two halogen atoms reduced DNA photocleavage. The substitution on the benzamidoxime scaffold was irrelevant to the activity. The mechanism of action indicated function in the absence of oxygen, probably via radicals derived from the N-O bond homolysis of the carbamates and in air via hydroxyl radicals and partially singlet oxygen. The UVA-vis area of absorption of the nitro-benzamidoxime p-Cl-PCMEs allowed for the investigation of their potential efficacy as photopesticides under UVA irradiation against the whitefly Bemisia tabaci, a major pest of numerous crops. The m-nitro derivative exhibited a moderate specificity against the adult population. Nymphs were not affected. The compound was inactive in the dark. This result may allow for the development of lead compounds for the control of agricultural insect pests that can cause significant economic damage in crop production.