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Journal of Arthropod-borne Diseases Dec 2023Bedbugs are nocturnal ectoparasites that have made a comeback after 20 years and have become one of the main challenges for pest control methods worldwide. Monitoring...
BACKGROUND
Bedbugs are nocturnal ectoparasites that have made a comeback after 20 years and have become one of the main challenges for pest control methods worldwide. Monitoring chemical pesticide resistance is crucial for identifying the best bed bugs management strategies to effectively manage arthropods. This study aims to assess the susceptibility of (Hemiptera: Cimicidae) collected from different parts of Khorasan-Razavi Province, (northeast of Iran) to deltamethrin (pyrethroid), phoxim (organothiophosphate) and propetamphos (phosphoramidate).
METHODS
This study was conducted from Dec 2020 to May 2021. The efficacy of three insecticides (deltamethrin, phoxim, and propetamphos) on adult was assessed using a bioassay method recommended by the World Health Organization (WHO),. Concentrations of deltamethrin used were 10, 20, 40, 80, 160, 320, 640, 1280, and 2560 ppm, while concentrations of phoxim and propetamphos were 10, 40, 160, and 320 ppm. The bed bugs were continuously exposed to the insecticide for 24 hours, and mortality was assessed at regular intervals during the observation period. The concentration-response data were subjected to POLO-PC software and data were analyzed by the one-way and two-way ANOVA procedures.
RESULTS
The lethal concentration fifty values of deltamethrin, phoxim and propetamphos on the examined bed bugs were 0.551, 0.148 and 0.237 ppm, respectively. Insecticide effects of phoxim were significantly higher (P≤ 0.05) compared to each of either deltamethrin and propetamphos agents.
CONCLUSION
The insecticide effects of phoxim against bed bugs were significantly higher compared to each of either deltamethrin or propetamphosinsecticides.
PubMed: 38868674
DOI: 10.18502/jad.v17i4.15299 -
The Science of the Total Environment Sep 2024The presence of certain associated bacteria has been reported to increase pest resistance to pesticides, which poses a serious threat to food security and the...
The presence of certain associated bacteria has been reported to increase pest resistance to pesticides, which poses a serious threat to food security and the environment. Researches on the above microbe-derived pesticide resistance would bring innovative approaches for pest management. Investigations into the phoxim resistance of Delia antiqua, one Liliaceae crop pests, revealed the contribution of a phoxim-degrading gut bacterium, D39, to this resistance. However, how the strain degraded phoxim was unknown. In this study, the role of D39 in phoxim degradation and resistance was first confirmed. DT, which had an identical taxonomy but lacked phoxim-degrading activity, was analyzed alongside D39 via comparative genomics to identify the potential phoxim degrading genes. In addition, degradation metabolites were identified, and a potential degradation pathway was proposed. Furthermore, the main gene responsible for degradation and the metabolites of phoxim were further validated via prokaryotic expression. The results showed that D39 contributed to resistance in D. antiqua larva by degrading phoxim. Phoxim was degraded by an enzyme encoded by the novel gene phoD in D39 to O,O-diethyl hydrogen phosphorothioate and 2-hydroxyimino-2-phenylacetonitrile. Finally, downstream products were metabolized in the tricarboxylic acid cycle. Further analysis via prokaryotic expression of phoD confirmed its degradation activity. The mechanisms through which gut microbes promote pesticide resistance are elucidated in this study. These results could aid in the development of innovative pest control methods. In addition, this information could also be used to identify microbial agents that could be applied for the remediation of pesticide contamination.
Topics: Organothiophosphorus Compounds; Gastrointestinal Microbiome; Insecticides; Animals; Insecticide Resistance; Inactivation, Metabolic; Bacteria
PubMed: 38862045
DOI: 10.1016/j.scitotenv.2024.173866 -
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi =... May 2024Objective To establish a colloidal gold immunochromatography and develop the corresponding test strip for detecting organophosphorus compounds including omethoate,...
Objective To establish a colloidal gold immunochromatography and develop the corresponding test strip for detecting organophosphorus compounds including omethoate, phoxim, dipterex, and parathion in fruits, vegetables and drinking water. Methods Artificial antigen molecules of organophosphorus compounds were synthesized using N-hydroxysuccinimide esters. Acetylcholinesterase antigen was prepared and purified, and the serum containing the corresponding antibody was prepared, purified, and labeled. The working parameters of the test strip were optimized, and the performance evaluation of it was conducted. Results The titer of the antisera ranged from 1:32 to 1:64, with a protein content of approximately 2 mg/mL. The purified polyclonal antibodies displayed target bands at relative molecular masses (M) of 25 000 and 55 000, indicating satisfactory purity. The reaction time of the test strips was between 5 to 10 minutes, with a detection limit for samples at 200 ng/mL. Both specificity and accuracy were satisfactory, and the test strip remained valid for 6 months. Conclusion A simple and rapid colloidal gold immunochromatography is established successfully for detecting several organophosphorus compounds and may be useful for on-site preliminary screening of samples in large quantities.
Topics: Gold Colloid; Organophosphorus Compounds; Chromatography, Affinity; Pesticides; Animals; Vegetables; Fruit; Acetylcholinesterase
PubMed: 38790099
DOI: No ID Found -
Fish & Shellfish Immunology Jul 2024The efficacy of phoxim in treating bacterial sepsis in silver carp is significant, yet its underlying mechanism remains elusive. This study aimed to establish a model of...
The efficacy of phoxim in treating bacterial sepsis in silver carp is significant, yet its underlying mechanism remains elusive. This study aimed to establish a model of Aeromonas veronii infection in silver carp and subsequently treat the infected fish with 10 μg/L phoxim. Kidney and intestine samples from silver carp were collected for transcriptome analysis and assessment of intestinal microbial composition, with the aim of elucidating the mechanism underlying the efficacy of phoxim in treating bacterial sepsis in silver carp. The results of transcriptome and intestinal microbial composition analysis of silver carp kidney indicated that A. veronii infection could up-regulate the expression of il1β, il6, nos2, ctsl, casp3 et al., which means, signifying that the kidney of silver carp would undergo inflammation, induce apoptosis, and alter the composition of intestinal microorganisms. Phoxim immersion might enhance the energy metabolism of silver carp and change its intestinal microbial composition, potentially elevating the antibacterial infection resistance of silver carp. These findings may contribute to an understanding of how phoxim can effectively treat bacterial sepsis in silver carp.
Topics: Animals; Carps; Fish Diseases; Organothiophosphorus Compounds; Gram-Negative Bacterial Infections; Aeromonas veronii; Gastrointestinal Microbiome
PubMed: 38750706
DOI: 10.1016/j.fsi.2024.109628 -
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 -
Bulletin of Entomological Research May 2024Carboxylesterases (CarEs) is an important detoxification enzyme system in phase Ⅰ participating in insecticides resistance. In our previous study, a CarEs gene from...
Carboxylesterases (CarEs) is an important detoxification enzyme system in phase Ⅰ participating in insecticides resistance. In our previous study, a CarEs gene from lepidoptera class, was screened out to be upregulated in a pyrethroids and organophosphates resistant population. Its overexpression was verified in two field-collected populations of (Lepidoptera: Noctuidae) resistant to pyrethroids and organophosphates by qRT-PCR. Spatiotemporal expression results showed that was highly expressed in the pupae stage and the digestive tissue midgut. To further explore its role in pyrethroids and organophosphates resistance, its metabolism activity to insecticides was determined by UPLC. Its recombinant protein showed significant metabolism activity to cyhalothrin and fenvalerate, but not to phoxim or chlorpyrifos. The metabolic activity of SlCarE054 to -cypermethrin showed stereoselectivity, with higher metabolic activity to -cypermethrin than the enantiomer -cypermethrin. The metabolite of -cypermethrin was identified as 3-phenoxybenzaldehyde. Further modelling and docking analysis indicated that -cypermethrin, cyhalothrin and fenvalerate could bind with the catalytic triad of the 3D structure of SlCarE054. The interaction of -cypermethrin with SlCarE054 also showed the lowest binding energy. Our work provides evidence that play roles in -cypermethrin resistance in .
PubMed: 38708572
DOI: 10.1017/S0007485324000282 -
Pesticide Biochemistry and Physiology May 2024The oriental tobacco budworm Helicoverpa assulta (Lepidoptera: Noctuidae) is a specialist pest that may cause serious damages to important crops such as chili pepper and...
The oriental tobacco budworm Helicoverpa assulta (Lepidoptera: Noctuidae) is a specialist pest that may cause serious damages to important crops such as chili pepper and tobacco. Various man-made insecticides have been applied to control the infestation of this pest. To understand how this pest copes with insecticides, it is required to identify key players involved in insecticide transformation. In this study, a P450 gene of CYP6B subfamily was identified in the oriental tobacco budworm, and its expression pattern was revealed. Moreover, the activities of HassCYP6B6 against 12 insecticides were explored using recombinant enzymes produced in the facile Escherichia coli. Data from metabolic experiments showed that HassCYP6B6 was able to metabolize conventional insecticides including organophosporates (diazinon, malathion, phoxim), carbamate propoxur, and pyrethroid esfenvalerate, while no significant metabolism was observed towards new-type pesticides such as neonicotinoids (acetamiprid, imidacloprid), diamides (chlorantraniliprole, cyantraniliprole), macrocyclic lactone (emamectin benzoate, ivermectin), and metaflumizone. Structures of metabolites were proposed based on mass spectrometry analyses. The results demonstrate that HassCYP6B6 plays important roles in the transformation of multiple insecticides via substrate-dependent catalytic mechanisms including dehydrogenation, hydroxylation and oxidative desulfurization. The findings have important applied implications for the usage of insecticides.
Topics: Insecticides; Animals; Moths; Insect Proteins; Cytochrome P-450 Enzyme System
PubMed: 38685236
DOI: 10.1016/j.pestbp.2024.105857 -
Spectrochimica Acta. Part A, Molecular... Aug 2024Based on the fact that not all chemical substances possess good Raman signals, this article focuses on the Raman silent region signals of pesticides with cyano group....
Based on the fact that not all chemical substances possess good Raman signals, this article focuses on the Raman silent region signals of pesticides with cyano group. Under the optimized conditions of methanol-water (1:1, v/v) as the solvent, irradiation at 302 nm light source for 20 min, and the use of 0.5 mol/L KI as the aggregating agent, Surface-enhanced Raman spectroscopy (SERS) method for azoxystrobin detection was developed by the Raman silent region signal of 2230 cm, and verified by detecting the spiked grapes with different concentrations of azoxystrobin. Other four pesticides with cyano group also could be identified at the peak of 2180 cm, 2205 cm, 2125 cm, and 2130 cm for acetamiprid, phoxim, thiacloprid and cymoxanil, respectively. When azoxystrobin or acetamiprid was mixed respectively with chlorpyrifos without cyano group, their SERS signals in the Raman silent region of chlorpyrifos were not interfered, while mixed with cymoxanil in different ratios (1:4, 1:1 and 4:1), respectively, each two pesticides with cyano group could be distinguished by the changes in the Raman silent region. In further, four pesticides with or without cyano group were mixed together in 1:1:1:1 (acetamiprid, cymoxanil, azoxystrobin chlorpyrifos), and each pesticide still could be identified even at 0.5 mg/L. The results showed that the SERS method combined with UV irradiation may provide a new way to monitor the pesticides with C≡N performance in the Raman silent region without interference from the food matrix.
Topics: Spectrum Analysis, Raman; Pesticides; Strobilurins; Pyrimidines; Vitis; Methacrylates; Neonicotinoids
PubMed: 38669978
DOI: 10.1016/j.saa.2024.124326 -
Journal of Hazardous Materials Jun 2024Trichoderma can enhance the metabolism of organophosphate pesticides in plants, but the mechanism is unclear. Here, we performed high-throughput transcriptome sequencing...
Trichoderma can enhance the metabolism of organophosphate pesticides in plants, but the mechanism is unclear. Here, we performed high-throughput transcriptome sequencing of roots upon Trichoderma asperellum (TM) inoculation and phoxim (P) application in tomato (Solanum lycopersicum L.). A total of 4059 differentially expressed genes (DEGs) were obtained, including 2110 up-regulated and 1949 down-regulated DEGs in P vs TM+P. COG and KOG analysis indicated that DEGs were mainly enriched in signal transduction mechanisms. We then focused on the pesticide detoxification pathway and screened out cytochrome P450 CYP736A12 as a putative gene for functional analysis. We suppressed the expression of CYP736A12 in tomato plants by virus-induced gene silencing and analyzed tissue-specific phoxim residues, oxidative stress markers, glutathione pool, GST activity and related gene expression. Silencing CYP736A12 significantly increased phoxim residue and induced oxidative stress in tomato plants, by attenuating the TM-induced increased activity of antioxidant and detoxification enzymes, redox homeostasis and transcripts of detoxification genes including CYP724B2, GSH1, GSH2, GR, GPX, GST1, GST2, GST3, and ABC. The study revealed a critical mechanism by which TM promotes the metabolism of phoxim in tomato roots, which can be useful for further understanding the Trichoderma-induced xenobiotic detoxification and improving food safety.
Topics: Solanum lycopersicum; Cytochrome P-450 Enzyme System; Plant Roots; Organothiophosphorus Compounds; Pesticide Residues; Oxidative Stress; Hypocreales
PubMed: 38631252
DOI: 10.1016/j.jhazmat.2024.134299 -
Pesticide Biochemistry and Physiology Mar 2024Chemical sensing systems are vital in the growth and development of insects. Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important natural enemy of many...
Chemical sensing systems are vital in the growth and development of insects. Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important natural enemy of many pests. The molecular mechanism of odorant binding proteins (OBPs) binding with common insecticides is still unknow in O. sauteri. In this study, we expressed in vitro OsauOBP8 and conducted fluorescence competition binding assay to investigate the function of OsauOBP8 to insecticides. The results showed that OsauOBP8 could bind with four common insecticides (phoxim, fenitrothion, chlorpyrifos, deltamethrin). Subsequently, we used molecular docking to predict and obtained candidate six amino acid residues (K4, K6, K13, R31, K49, K55) and then mutated. The result showed that three key residues (K4, K6, R31) play important role in OsauOBP8 bound to insecticides. Our study identified the key binding sites of OsauOBP8 to insecticides and help to better understand the molecular mechanism of OBPs to insecticides in O. sauteri.
Topics: Animals; Insecticides; Molecular Docking Simulation; Heteroptera; Receptors, Odorant
PubMed: 38582604
DOI: 10.1016/j.pestbp.2024.105842