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Ecotoxicology and Environmental Safety Sep 2022Isoprocarb is a widely used carbamate insecticide in agriculture and aquaculture. Overuse of isoprocarb always leaves toxic residues in soil and water, however, the...
Isoprocarb is a widely used carbamate insecticide in agriculture and aquaculture. Overuse of isoprocarb always leaves toxic residues in soil and water, however, the potential ecotoxicity of isoprocarb to organisms is still confusing. In this study, zebrafish embryo was used as a model to evaluate the toxicity of isoprocarb. Zebrafish embryos (96 hpf) were separately exposed at different concentrations of isoprocarb. The mortality rate, hatchability rate, average heart beat of the zebrafish embryo were separately calculated. Our results suggested that exposure to isoprocarb induced developmental toxicity in zebrafish embryos. HE staining showed that exposure to isoprocarb caused developmental defect in the hindbrain of zebrafish embryos. As expected, the behavioral analysis also showed that the motor ability of zebrafish embryos were significantly inhibited following exposure to isoprocarb. In terms of mechanism, The expressions of genes involved in neurodevelopment signaling pathways, such as foxo3a, gfap, syn2a, elavl3 and sox19b, were inhibited in zebrafish embryos after exposure to isoprocarb. The acetylcholinesterase (AChE) activity was also reduced in isoprocarb-treated zebrafish embryos. Moreover, oxidative stress was induced by increasing the reactive oxygen species (ROS) level and decreasing the activity of antioxidant enzyme (SOD) after exposure to isoprocarb. Expectedly, acridine orange (AO) staining and the detection of some apoptosis-related genes revealed that oxidative stress resulted in apoptosis. In short, the expressions of genes associated with the neurodevelopmental signaling pathway are inhibited, and oxidative stress is also induced in zebrafish embryos after exposure to isoprocarb, which may be the molecular basics of isoprocarb-induced neurotoxicity in zebrafish embryos.
Topics: Acetylcholinesterase; Animals; Apoptosis; Carbamates; Embryo, Nonmammalian; Neurotoxicity Syndromes; Oxidative Stress; SOX Transcription Factors; Water Pollutants, Chemical; Zebrafish; Zebrafish Proteins
PubMed: 35816841
DOI: 10.1016/j.ecoenv.2022.113870 -
Frontiers in Physiology 2018Carboxylesterase (CarE) is an important class of detoxification enzymes involved in insecticide resistance. However, the molecular mechanism of CarE-mediated insecticide...
Carboxylesterase (CarE) is an important class of detoxification enzymes involved in insecticide resistance. However, the molecular mechanism of CarE-mediated insecticide resistance in , a problematic agricultural pest, remains largely unknown. In the present study, an isoprocarb-resistant (IS-R) strain and a cyhalothrin-resistant (CY-R) strain were successively selected from a susceptible (SS) strain of . The enzyme activity indicated that enhanced carboxylesterase activity contributes to isoprocarb and cyhalothrin resistance. The expression levels of putative genes were examined and compared among IS-R, CY-R, and SS strains, and only the carboxylesterase gene () was significantly over expressed in both the IS-R and CY-R strains compared to the SS strain. The coding region of the CarE gene was cloned and expressed in . The purified RpCarE protein was able to catalyze the model substrate, α-naphtyl acetate (cat = 5.50 s; m = 42.98 μM). HPLC assay showed that the recombinant protein had hydrolase activity against isoprocarb and cyhalothrin. The modeling and docking analyses consistently indicated these two insecticide molecules fit snugly into the catalytic pocket of RpCarE. Taken together, these findings suggest that RpCarE plays an important role in metabolic resistance to carbamates and pyrethroids in .
PubMed: 30090072
DOI: 10.3389/fphys.2018.00992 -
Scientific Reports Mar 2023In comparison to an open field, greenhouses utilize much more pesticides. The non-occupational exposure risk caused by pesticide drift is unknown. In this study, within...
In comparison to an open field, greenhouses utilize much more pesticides. The non-occupational exposure risk caused by pesticide drift is unknown. In this study, within 8 months (from March 2018 to October 2018), air samples were collected from indoor and outdoor houses and public areas near greenhouses in vegetable growing areas (eggplant, leek, garlic, etc.), and qualitative and quantitative analyses of pesticides were carried out. Using a 95% confidence interval, six pesticides (acetamiprid, difenoconazole, thiazophos, isoprocarb, malathion, and pyridaben) were detected. The results of the safety assessment showed that the non-cancer exposure risk of single pesticides for all residents in the agricultural areas was within the acceptable range, and the excess lifetime cancer risk of all residents inhaling difenoconazole exceeded 1E-6, and the agricultural region urgently needs increased cancer regulatory scrutiny. But combined toxicity of six pesticides not evaluated due to lack of suitable data. Comparison with open field scenes, the results show that pesticide levels to airborne are lower in greenhouse regions.
Topics: Humans; Pesticides; Agriculture; Risk Assessment; Environment; Malathion
PubMed: 36991103
DOI: 10.1038/s41598-023-32458-y -
Insects Nov 2021Monitoring is an important component of insecticide resistance management. In this study, resistance monitoring was conducted on 18 field populations in China. The...
Monitoring is an important component of insecticide resistance management. In this study, resistance monitoring was conducted on 18 field populations in China. The results showed that developed high levels of resistance to chlorpyrifos and buprofezin, and showed low to moderate levels of resistance to imidacloprid, thiamethoxam, dinotefuran, clothianidin, sulfoxaflor, isoprocarb and ethofenprox. remained susceptible or low levels of resistance to nitenpyram. LC values of nitenpyram and dinotefuran, imidacloprid, thiamethoxam, clothianidin and chlorpyrifos exhibited significant correlations, as did those between dinotefuran and thiamethoxam, clothianidin, sulfoxaflor, imidacloprid, isoprocarb and buprofezin. Similarly, significant correlations were observed between thiamethoxam and clothianidin, sulfoxaflor and imidacloprid. In addition, the activity of EST in field populations of were significantly correlated with the LC values of nitenpyram, thiamethoxam and clothianidin. These results will help inform effective insecticide resistance management strategies to delay the development of insecticide resistance in .
PubMed: 34940166
DOI: 10.3390/insects12121078 -
PloS One 2016NADPH-cytochrome P450 reductase (CPR) plays an important role in the cytochrome P450 (CYP)-mediated metabolism of endogenous and exogenous substrates. CPR has been found...
NADPH-cytochrome P450 reductase (CPR) plays an important role in the cytochrome P450 (CYP)-mediated metabolism of endogenous and exogenous substrates. CPR has been found to be associated with insecticide metabolism and resistance in many insects. However, information regarding CPR in the bird cherry-oat aphid, Rhopalosiphum padi, is unavailable. In the current study, a full-length cDNA (2,476 bp) of CPR (RpCPR) encoding 681 amino acids was cloned from R. padi. Nucleotide sequence and deduced amino acid sequence analysis showed that RpCPR exhibits characteristics of classical CPRs and shares high identities with those of other insects, especially with the pea aphid, Acyrthosiphon pisum. The mRNA of RpCPR was expressed at all developmental stages, with the highest expression level found in the second instar and the lowest in adult. Expression levels of RpCPR in isoprocarb-resistant and imidacloprid-resistant strains were 3.74- and 3.53-fold higher, respectively, than that of a susceptible strain. RpCPR expression could also be induced by low concentrations (LC30) of isoprocarb and imidacloprid. Moreover, we sequenced the open reading frame (ORF) of RpCPR from 167 field samples collected in 11 geographical populations. Three hundred and thirty-four SNPs were detected, of which, 65 were found in more than two individuals. One hundred and ninety-four missense mutations were present in the amino acid sequence, of which, the P484S mutant had an allele frequency of 35.1%. The present results suggest that RpCPR may play an important role in the P450-mediated insecticide resistance of R. padi to isoprocarb and imidacloprid and possibly other insecticides. Meanwhile, RpCPRmaintains high genetic diversity in natural individuals, which provides the possibility of studying potential correlations between variants and certain special physiological characters.
Topics: Amino Acid Sequence; Animals; Aphids; Base Sequence; Carbamates; Cloning, Molecular; Gene Frequency; Imidazoles; Insecticide Resistance; Insecticides; Mutation, Missense; NADPH-Ferrihemoprotein Reductase; Neonicotinoids; Nitro Compounds; Polymorphism, Single Nucleotide; RNA, Messenger; Sequence Analysis, DNA
PubMed: 27124302
DOI: 10.1371/journal.pone.0154633 -
Insects May 2020The ATP-binding cassette (ABC) transporter superfamily is one of the largest groups of proteins and plays a non-negligible role in phase III of the detoxification...
The ATP-binding cassette (ABC) transporter superfamily is one of the largest groups of proteins and plays a non-negligible role in phase III of the detoxification process, which is highly involved in the response of insects to environmental stress (plant secondary metabolites and insecticides). In the present study, in , we identified 32 ABC transporters, which are grouped into eight subfamilies (ABCA-H) based on phylogenetic analysis. The temporal and spatial expression profiles suggested that the nymphal stages (1st-5th) and adult males showed similarity, which was different from eggs and adult females, and , , , , , , , and were highly expressed in the midgut and Malpighian tubules. In addition, , which belongs to the ABC transporter G subfamily, was significantly upregulated after exposure to sulfoxaflor, nitenpyram, clothianidin, etofenprox, chlorpyrifos, and isoprocarb. Moreover, verapamil significantly increased the sensitivity of to nitenpyram, clothianidin, etofenprox, chlorpyrifos, and isoprocarb. These results provide a basis for further research on ABC transporters involved in detoxification in , and for a more comprehensive understanding of the response of to environmental stress.
PubMed: 32370222
DOI: 10.3390/insects11050280 -
Ecotoxicology and Environmental Safety Aug 2021Carbaryl is the representative of carbamate insecticide. As an acetylcholinesterase inhibitor, it poses potential threat to humans and other non-target organisms....
Carbaryl is the representative of carbamate insecticide. As an acetylcholinesterase inhibitor, it poses potential threat to humans and other non-target organisms. Agrobacterium sp. XWY-2, which could grow with carbaryl as the sole carbon source, was isolated and characterized. The carH gene, encoding a carbaryl hydrolase, was cloned from strain XWY-2 and expressed in Escherichia coli BL21 (DE3). CarH was able to hydrolyze carbamate pesticides including carbaryl, carbofuran, isoprocarb, propoxur and fenobucarb efficiently, while it hydrolyzed oxamyl and aldicarb poorly. The optimal pH of CarH was 8.0 and the optimal temperature was 30 ℃. The apparent K and k values of CarH for carbaryl were 38.01 ± 2.81 μM and 0.33 ± 0.01 s, respectively. The point mutation experiment demonstrated that His341, His343, His346, His416 and D437 are the key sites for CarH to hydrolyze carbaryl.
PubMed: 34416635
DOI: 10.1016/j.ecoenv.2021.112666 -
International Journal of Molecular... Aug 2022Acetamiprid is widely used in paddy fields for controlling (Stål). However, the risk of resistance development, the cross-resistance pattern and the resistance...
Acetamiprid is widely used in paddy fields for controlling (Stål). However, the risk of resistance development, the cross-resistance pattern and the resistance mechanism of acetamiprid in this pest remain unclear. In this study, an acetamiprid-resistant strain (AC-R) was originated from a field strain (UNSEL) through successive selection with acetamiprid for 30 generations, which reached 60.0-fold resistance when compared with a laboratory susceptible strain (AC-S). The AC-R strain (G) exhibited cross-resistance to thiamethoxam (25.6-fold), nitenpyram (21.4-fold), imidacloprid (14.6-fold), cycloxaprid (11.8-fold), dinotefuran (8.7-fold), sulfoxaflor (7.6-fold) and isoprocarb (8.22-fold), while there was no cross-resistance to etofenprox, buprofezin and chlorpyrifos. Acetamiprid was synergized by the inhibitor piperonyl butoxide (2.2-fold) and the activity of cytochrome P450 monooxygenase was significantly higher in the AC-R strain compared with the AC-S strain, suggesting the critical role of P450. The gene expression results showed that the P450 gene was significantly overexpressed in AC-R compared with the AC-S and UNSEL strains. In addition, the RNA interference (RNAi) of significantly increased the susceptibility of AC-R to acetamiprid. Molecular docking predicted that acetamiprid and CYP6ER1 had close binding sites, and the nitrogen atoms had hydrogen bond interactions with CYP6ER1. These results demonstrated that the overexpression of contributed to acetamiprid resistance in .
Topics: Animals; Hemiptera; Insecticide Resistance; Insecticides; Molecular Docking Simulation; Neonicotinoids; Nitro Compounds
PubMed: 36012694
DOI: 10.3390/ijms23169429 -
ACS Omega Apr 2022Magnetic sorbents based on iron-aluminum-mixed metal hydroxides composited with metal-organic frameworks (MOFs) were designed and synthesized using different benzoate...
Magnetic Solid-Phase Extraction of Carbamate Pesticides Using Magnetic Metal-Organic Frameworks Derived from Benzoate Ligands, Followed by Digital Image Colorimetric Screening and High-Performance Liquid Chromatography Analysis.
Magnetic sorbents based on iron-aluminum-mixed metal hydroxides composited with metal-organic frameworks (MOFs) were designed and synthesized using different benzoate ligands, including terephthalic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 1,3,5-benzenetricarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid. The magnetic MOF derived from terephthalic acid ligand exhibited an excellent extraction efficiency, with adsorption capacities in the range of 2193-4196 mg kg, and was applied for magnetic solid-phase extraction (MSPE) of carbamate pesticides, that is, bendiocarb, carbosulfan, carbofuran, carbaryl, propoxur, isoprocarb, and promecarb. Simple digital image colorimetry based on the diazotization reaction and high-performance liquid chromatography (HPLC) were utilized for fast screening and quantification purposes, respectively. A good analytical performance for a simple screening approach using portable equipment was obtained with detection limits in the range of 1.0-18.0 μg L. Under the optimized MSPE-HPLC conditions, the entire developed procedure provided a wide linear range between 0.015 and 1000 μg L, low limits of detection, and limits of quantitation ranging from 0.005 to 0.090 and 0.015-0.300 μg L, respectively. Enrichment factors up to 184 were achieved. The intra- and interday relative standard deviations were below 6.7 and 9.4%, respectively. The proposed MSPE-digital image colorimetry and MSPE-HPLC methods were successfully applied for screening and determining carbamate pesticides in fruits and vegetables. The recoveries were obtained in a satisfactory range of 71.5-122.8%. This discovery has led to the development of integration methods using newly synthesized sorbent materials for the enrichment of carbamate pesticides prior to their analysis in complicated samples. The developed MSPE coupled with digital image colorimetry was efficient for fast carbamate contamination screening, while MSPE-HPLC offered a sensitive analytical methodology for quantifying contaminated samples.
PubMed: 35449973
DOI: 10.1021/acsomega.2c00596 -
Applied and Environmental Microbiology Dec 2020Methomyl {bis[1-methylthioacetaldehyde--(-methylcarbamoyl)oximino]sulfide} is a highly toxic oxime carbamate insecticide. Several methomyl-degrading microorganisms have...
Methomyl {bis[1-methylthioacetaldehyde--(-methylcarbamoyl)oximino]sulfide} is a highly toxic oxime carbamate insecticide. Several methomyl-degrading microorganisms have been reported so far, but the role of specific enzymes and genes in this process is still unexplored. In this study, a protein annotated as a carbamate C-N hydrolase was identified in the methomyl-degrading strain MDW-2, and the encoding gene was termed A comparative analysis between the mass fingerprints of AmeH and deduced proteins of the strain MDW-2 genome revealed AmeH to be a key enzyme of the detoxification step of methomyl degradation. The results also demonstrated that AmeH was a functional homodimer with a subunit molecular mass of approximately 34 kDa and shared the highest identity (27%) with the putative formamidase from ATCC 24843. AmeH displayed maximal enzymatic activity at 50°C and pH 8.5. and of AmeH for methomyl were 87.5 μM and 345.2 s, respectively, and catalytic efficiency (/ ) was 3.9 μM s Phylogenetic analysis revealed AmeH to be a member of the FmdA_AmdA superfamily. Additionally, five key amino acid residues (162, 164, 191, 193, and 207) of AmeH were identified by amino acid variations. Based on the structural characteristic, carbamate insecticides can be classified into oxime carbamates (methomyl, aldicarb, oxamyl, etc.) and -methyl carbamates (carbaryl, carbofuran, isoprocarb, etc.). So far, research on the degradation of carbamate pesticides has mainly focused on the detoxification step and hydrolysis of their carbamate bond. Several genes, such as , , , and , and their encoding enzymes have also been reported to be involved in the detoxification step. However, none of these enzymes can hydrolyze methomyl. In this study, a carbamate C-N hydrolase gene, , responsible for the detoxification step of methomyl in strain MDW-2 was cloned and the key amino acid sites of AmeH were investigated. These findings provide insight into the microbial degradation mechanism of methomyl.
Topics: Biodegradation, Environmental; Hydrolases; Inactivation, Metabolic; Methomyl; Phyllobacteriaceae; Sequence Analysis, Protein
PubMed: 33097501
DOI: 10.1128/AEM.02005-20