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Pest Management Science Apr 2021Carboxylesterases (CarEs) are associated with detoxification of xenobiotics, including insecticides, in organism bodies. Overexpression of CarE genes is considered to...
BACKGROUND
Carboxylesterases (CarEs) are associated with detoxification of xenobiotics, including insecticides, in organism bodies. Overexpression of CarE genes is considered to have an important role in insecticide resistance in insects, however its involvement in multi-insecticide resistance has rarely been reported. This study aimed to assess the function of a CarE gene (PxαE8) in resistance to five insecticides in Plutella xylostella.
RESULTS
Relative expression of PxαE8 in three multi-insecticide-resistant Plutella xylostella populations, GD-2017, GD-2019 and HN, was14.8-, 19.5- and 28.0-fold higher than that in the susceptible population. Exposure to lethal concentrations associated with 25% mortality (LC ) of beta-cypermethrin, chlorantraniliprole, metaflumizone, phoxim and tebufenozide could induce the specific activity of CarEs and increase the relative expression of PxαE8. By contrast, knockdown of PxαE8 expression dramatically reduced the activity of CarEs and increased the resistance of P. xylostella (GD-2019) larvae to beta-cypermethrin and phoxim by 47.4% and 45.5%, respectively. Further, a transgenic line of Drosophila melanogaster overexpressing PxαE8 was constructed and the bioassay results showed that the tolerance of transgenic Drosophila to beta-cypermethrin and phoxim was 3.93- and 3.98-fold higher than that of the untransgenic line.
CONCLUSION
These results provide evidence that overexpression of PxαE8 is involved in resistance, at least to beta-cypermethrin and phoxim, in multi-insecticide-resistant P. xylostella populations, which could help in further understanding the molecular mechanisms of multi-insecticide resistance in this pest. © 2020 Society of Chemical Industry.
Topics: Animals; Carboxylesterase; Carboxylic Ester Hydrolases; Drosophila melanogaster; Insecticide Resistance; Insecticides; Larva; Moths; Organothiophosphorus Compounds; Pyrethrins
PubMed: 33342080
DOI: 10.1002/ps.6238 -
Analytical Chemistry Feb 2022A novel high-throughput aptamer microarray fluorescent method based on thioflavin T (ThT) was established for the sensitive detection of phoxim, parathion,...
A novel high-throughput aptamer microarray fluorescent method based on thioflavin T (ThT) was established for the sensitive detection of phoxim, parathion, fensulfothion, and isocarbophos. In this work, the aptamers in binding buffer tended to have the antiparallel G-quadruplex structure, which can bind ThT and release its potential fluorescence signal. However, when the organophosphorus pesticides (OPs) were present, partial aptamers preferred to bind them, forcing the displacement of ThT from the G-quadruplex and resulting in the significant decrease in fluorescence signal. Under optimal experimental conditions (12T spacer, 300 nM aptamer, and 80 μM ThT), the OP aptamer microarray has low limits of detection of 25.4 ng/mL for phoxim, 12.0 ng/mL for parathion, 7.7 ng/mL for fensulfothion, and 9.9 ng/mL for isocarbophos. The accuracy and reliability of the method is further verified by testing the recovery rate of OPs spiked in two different complicated sample matrices (pears and radishes). It is worth mentioning that not only the developed aptamer microarray technology has low sensitivity and a broad spectrum, but it also allows for high-throughput and rapid analysis of a variety OPs, which overcomes some of the shortcomings of other OP detection methods.
Topics: Aptamers, Nucleotide; Biosensing Techniques; Fluorescent Dyes; Organophosphorus Compounds; Pesticides; Reproducibility of Results; Spectrometry, Fluorescence
PubMed: 35133802
DOI: 10.1021/acs.analchem.1c04650 -
Toxicology Research Mar 2018Research has shown that organophosphorus pesticides impair glucose homeostasis and cause insulin resistance and type 2 diabetes. The current study investigates the...
Research has shown that organophosphorus pesticides impair glucose homeostasis and cause insulin resistance and type 2 diabetes. The current study investigates the influence of phoxim on insulin signaling pathways and the protective effects of vitamin E. Phoxim (180 mg kg) and VE (200 mg kg) were administered orally to Sprague-Dawley rats over a period of 28 consecutive days. After exposure to phoxim, the animals showed glucose intolerance and hyperinsulinemia during glucose tolerance tests, and insulin tolerance tests demonstrated an impaired glucose-lowering effect of insulin. Phoxim increases the fasting glucose, insulin and cholesterol levels, as well as the liver hexokinase activity (HK) significantly while decreasing the high density lipoprotein (HDL) cholesterol, and glycogen content in the liver and skeletal muscles observably. Furthermore, we observed an increase of insulin resistance biomarkers and a decrease of insulin sensitivity indices. The insulin receptor substrate (IRS)-2 mRNA expressions of liver and skeletal muscles were down-regulated by phoxim, while the expression of IRS-1 showed no difference. There were no differences in triglycerides, LDL-cholesterol, and fasting glucose treated with phoxim. On the basis of biochemical and molecular findings, phoxim has been determined to impair glucose homeostasis through insulin resistance and insulin signaling pathway disruptions resulting in a reduced function of insulin in hepatocytes and muscles. VE supplementation reduced the fasting glucose, increased the glycogen content and HDL-cholesterol, but did not reduce the insulin resistance indices, when phoxim-treated rats were compared to VE supplemented rats. Overall, this study shows that vitamin E modifies the phoxim toxicity in rats only to a moderate degree.
PubMed: 30090575
DOI: 10.1039/c7tx00243b -
Archives of Environmental Contamination... Apr 2015Bombyx mori (B. mori) is often subjected to phoxim poisoning in China due to phoxim exposure, which leads to a decrease in silk production. Nanoparticulate (NP) titanium...
Bombyx mori (B. mori) is often subjected to phoxim poisoning in China due to phoxim exposure, which leads to a decrease in silk production. Nanoparticulate (NP) titanium dioxide (nano-TiO2) has been shown to attenuate damages in B. mori caused by phoxim exposure. However, little is known about the molecular mechanisms of midgut injury due to organophosphorus insecticide exposure and its repair by nano-TiO2 pretreatment. In this study, phoxim exposure for 36 h led to significant decreases in body weight and survival and increased oxidative stress and midgut injury. Pretreatment with nano-TiO2 attenuated the phoxim-induced midgut injury, increased body weight and survival, and decreased oxidative stress in the midgut of B. mori. Digital gene-expression data showed that exposure to phoxim results in significant changes in the expression of 254 genes in the phoxim-exposed midgut and 303 genes in phoxim + nano-TiO2-exposed midgut. Specifically, phoxim exposure led to upregulation of Tpx, α-amylase, trypsin, and glycoside hydrolase genes involved in digestion and absorption. Phoxim exposure also led to the downregulation of Cyp450 and Cyp4C1 genes involved in an antioxidant capacity. In contrast, a combination of both phoxim and nano-TiO2 treatment significantly decreased the change in α-amylase, trypsin, and glycoside hydrolases (GHs), which are involved in digestion and absorption. These results indicated that Tpx, α-amylase, trypsin, GHs, Cyp450, and Cyp4C1 may be potential biomarkers of midgut toxicity caused by phoxim exposure and the attenuation of these toxic impacts by nano-TiO2.
Topics: Animals; Bombyx; Digestive System; Insecticides; Nanoparticles; Organothiophosphorus Compounds; Oxidative Stress; Titanium
PubMed: 25552327
DOI: 10.1007/s00244-014-0121-8 -
Environmental Science and Pollution... Sep 2018Phoxim is an organic phosphorus pesticide that remains easily in the environment, such as human food and animal feed. The objective of this study was to explore the...
Phoxim is an organic phosphorus pesticide that remains easily in the environment, such as human food and animal feed. The objective of this study was to explore the effect of vitamin E on phoxim-induced oxidative stress in the intestinal tissues of Sprague-Dawley (SD) rats. Forty-eight Sprague-Dawley rats were randomly assigned to a control group and three treatment groups: treatment group 1 (phoxim: 20 mg/kg·BW), treatment group 2 (phoxim: 180 mg/kg·BW), and treatment 3 (vitamin E + phoxim: 200 mg/kg·BW + 180 mg/kg·BW). Phoxim was given by gavage administration once a day for 28 days. The results showed that phoxim significantly reduced jejunum villus height in rats (P < 0.05), and decreased the mRNA expression of junction protein genes of rats, including Occlidin and Claudin-4 (P < 0.05). Phoxim reduced GSH content and T-AOC level in the intestinal mucosa (P < 0.05). The mRNA expression levels of oxidative stress-related genes (Nrf2 and GPx2) were decreased. The mRNA expression of SOD was significantly increased. In addition, phoxim increased the level of interleukin-6 (IL-6) in jejunum mucosa and significantly reduced the level of IL-8 in ileum mucosas, while significantly increased TNF-α secretion. The mRNA expression levels of IL-1β, IL-6, and IL-8 were significantly decreased, and mRNA expression of TNF-α was significantly increased (P < 0.05). Phoxim also increased the DNA expression of total cecal bacteria and Escherichia coli, inhibited the DNA expression of Lactobacillus and destroyed the intestinal barrier. Two hundred milligrams per kilogram BW vitamin E reduced the effect of phoxim on intestinal structure, alleviated the oxidative stress in intestinal tissue, and decreased the level of TNF-α. The mRNA expressions of antioxidative stress genes (SOD and GPx2) were significantly increased. The DNA expression level of Lactobacillus was significantly increased. In conclusion, vitamin E helped reduce the toxicity of organophosphate pesticides, such as phoxim on rat intestinal tissue.
Topics: Animals; Antioxidants; Dose-Response Relationship, Drug; Environmental Pollutants; Intestinal Mucosa; Lactobacillus; Male; Organothiophosphorus Compounds; Oxidative Stress; Random Allocation; Rats; Rats, Sprague-Dawley; Vitamin E
PubMed: 30003487
DOI: 10.1007/s11356-018-2666-y -
Journal of Agricultural and Food... Jan 2021Insect resistance to insecticides is an increasingly serious problem, and the resistant mechanisms are complicated. The resistance research based on the chemosensory...
Insect resistance to insecticides is an increasingly serious problem, and the resistant mechanisms are complicated. The resistance research based on the chemosensory pathway is one of the hot problems at present, but the specific binding mechanism of chemosensory genes and insecticides remains elusive. The binding mechanism of GOBP2 (belong to insect chemosensory gene) with two insecticides was investigated by computational and experimental approaches. Our calculation results indicated that four key residues (Phe12, Ile52, Ile94, and Phe118) could steadily interact with these two insecticides and be assigned as hotspot sites responsible for their binding affinities. The significant alkyl-π and hydrophobic interactions involved by these four hotspot residues were found to be the driving forces for their binding affinities, especially for two residues (Phe12 and Ile94) that significantly contribute to the binding of chlorpyrifos, which were also validated by our binding assay results. Furthermore, we also found that the GOBP2-chlorpyrifos/phoxim complexes can be more efficiently converged in the residue-specific force field-(RSFF2C) and its higher accuracy and repeatability in protein dynamics simulation, per-residue free energy decomposition, and computational alanine scanning calculations have also been achieved in this paper. These findings provided useful insights for efficient and reliable calculation of the binding mechanism of relevant GOBPs with other insecticides, facilitating to develop new and efficient insecticides targeting the key sites of GOBP2.
Topics: Animals; Chlorpyrifos; Insect Proteins; Molecular Dynamics Simulation; Moths; Organothiophosphorus Compounds; Protein Binding; Receptors, Odorant
PubMed: 33356208
DOI: 10.1021/acs.jafc.0c05389 -
Analytica Chimica Acta May 2022In this work, we reported the first use of a novel fluorescent probe for phoxim detection based on yellowish-green emissive carbon quantum dots (CQDs). By facile one-pot...
In this work, we reported the first use of a novel fluorescent probe for phoxim detection based on yellowish-green emissive carbon quantum dots (CQDs). By facile one-pot hydrothermal treatment of citric acid and p-phenylenediamine, the CQDs with yellowish-green luminescence were synthesized. The sensing mechanism is based on the quenching effect of phoxim on the fluorescence emission of CQDs by inner filter effect (IFE). The CQDs showed a good sensitivity and selectivity to phoxim detection and dual good linear relationships were provided in the concentration ranges of 1-10 μM and 10-98 μM, associated with the limit of detection of 0.09 μM. The proposed assay has been allowed to detect phoxim in real samples with satisfying recoveries ranging from 93 to 105.9%. Furthermore, due to the low cytotoxicity and excellent biocompatibility, the as-prepared CQDs was successfully used for cell imaging, demonstrating the considerable potential applications of such CQDs in biological field.
Topics: Carbon; Fluorescent Dyes; Organothiophosphorus Compounds; Quantum Dots
PubMed: 35473876
DOI: 10.1016/j.aca.2021.338685 -
Journal of Agricultural and Food... May 2024Aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (ARNT) mediate the responses of adaptive metabolism to various xenobiotics. Here, we...
Aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (ARNT) mediate the responses of adaptive metabolism to various xenobiotics. Here, we found that and are highly expressed in the midgut of larvae. The expression of and was significantly increased after exposure to imidacloprid and phoxim. The knockdown of and significantly decreased the expression of and as well as P450 enzyme activity and caused a significant increase in the sensitivity of larvae to imidacloprid and phoxim. Exposure to β-naphthoflavone (BNF) significantly increased the expression of , , and as well as P450 activity and decreased larval sensitivity to imidacloprid and phoxim. Furthermore, and were significantly induced by imidacloprid and phoxim, and the silencing of these two genes significantly reduced larval tolerance to imidacloprid and phoxim. Taken together, the BoAhRBoARNT pathway plays key roles in larval tolerance to imidacloprid and phoxim by regulating the expression of and .
Topics: Animals; Insecticides; Larva; Nitro Compounds; Neonicotinoids; Insect Proteins; Receptors, Aryl Hydrocarbon; Diptera; Aryl Hydrocarbon Receptor Nuclear Translocator; Cytochrome P-450 Enzyme System; Inactivation, Metabolic; Transcription Factors
PubMed: 38712504
DOI: 10.1021/acs.jafc.4c00358 -
Food Chemistry Jul 2022A ratiometric electrochemical immunosensor, based on DNA tetrahedron nanostructure (DTNS), is introduced for vegetable phoxim determination. DTNS spontaneously adheres...
Ratiometric immunosensor with DNA tetrahedron nanostructure as high-performance carrier of reference signal and its applications in selective phoxim determination for vegetables.
A ratiometric electrochemical immunosensor, based on DNA tetrahedron nanostructure (DTNS), is introduced for vegetable phoxim determination. DTNS spontaneously adheres onto gold-nanoparticle-modified electrode and forms stable three-dimensional structure, providing plenty of binding sites to the built-in reference, methylene blue (MB). Monoclonal antibody (m-Ab) is vertically linked onto DTNS vertex, selectively responses antigenic phoxim, and promotes the target signal of I. Thus, a ratiometric indicator, I/I, is sensibly established with the target signal (I) and the reference signal (I). Modifications, mechanisms and advances of the proposed method are subsequently examined with morphological methods and electrochemical experiments. This method brings considerable advances in analytical behaviors. The ratiometric signal presents better performance than solo system in repeatability and long-time stability. As-fabricated sensor presents wide dynamic range as 0.1∼30 μg/L, and limit of detection is well defined as 0.003 μg/L (S/N = 3). Finally, this method is verified with real-vegetable-sample analysis, certified HPLC and recovery test.
Topics: Biosensing Techniques; DNA; Electrochemical Techniques; Gold; Immunoassay; Limit of Detection; Methylene Blue; Nanostructures; Organothiophosphorus Compounds; Vegetables
PubMed: 35182867
DOI: 10.1016/j.foodchem.2022.132445 -
Food Chemistry Jun 2022Organophosphorus pesticides will not only affect human health, but will also have serious impacts on the ecological environment. A simple, economical, safe, efficient,...
Organophosphorus pesticides will not only affect human health, but will also have serious impacts on the ecological environment. A simple, economical, safe, efficient, green and pollution-free and highly sensitive method was successfully established to analyze organophosphorus pesticides in different coarse cereals' samples. Under the optimal experimental conditions, the method was linear, the correlation coefficient are higher than 0.9639. The detection limits of trichlorfon, chlorpyrifos, phoxim, fenthion, and diazinon were 2.6, 2.0, 4.3, 2.0, and 2.8 μg/kg. The recoveries ranged from 92.8 to 105.2%, the relative standard deviation is less than 5.2%. The results obtained show that the proposed method has the advantages of economy, safety, green and pollution-free, high recovery efficiency, simple use of the instrument, simple operation, and can be used with many subsequent instruments.
Topics: Chlorpyrifos; Edible Grain; Humans; Ionic Liquids; Organophosphorus Compounds; Pesticides
PubMed: 35065493
DOI: 10.1016/j.foodchem.2022.132161