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Environmental Science and Pollution... Aug 2022With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high...
With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high water content have been developed and the preparation processes also evolved, but these processes still exist some problems, such as poor controllability and high energy consumption. Microfluidic is a controllable nanoemulsion preparation system which mainly applied to pharmaceutical synthesis. In this study, the pesticide phoxim nanoemulsion was prepared by microfluidic technology. The optimized formulation of phoxim nanoemulsion was composed of Tween 80 and pesticide emulsifier 500 as surfactant, hexyl acetate as oil, and n-propanol as co-surfactant. Moreover, when the flow rates of water and oil in the microfluidic system were adjusted to 5 μL/min and 20 μL/min, phoxim nanoemulsion was obtained with a cloud point/boiling point of 109 °C, a particle size of 21.5 ± 0.8 nm and a potential value of - 18.7 ± 0.6 mV. Furthermore, the nanoemulsion had a rapid release effect in vitro which could be fitted by the Ritger-Peppas model. The feeding toxicity of the phoxim nanoemulsion was higher than that of commercial formulation while the contact killing effect was higher than that of the active ingredient. Therefore, pesticide dosage was reduced and the insecticidal effect was enhanced by using phoxim nanoemulsions. These results also confirm the potential of microfluidics as a green process to produce pesticide nanoemulsions.
Topics: Animals; Emulsions; Microfluidics; Organothiophosphorus Compounds; Particle Size; Pesticides; Spodoptera; Surface-Active Agents; Water
PubMed: 35394625
DOI: 10.1007/s11356-022-20001-x -
Analytical Methods : Advancing Methods... Jul 2021By integrating the steps of direct magnetization and one-pot pyrolysis, a three-dimensional (3D) magnetic graphene oxide-functionalized citrus peel-derived bio-composite...
By integrating the steps of direct magnetization and one-pot pyrolysis, a three-dimensional (3D) magnetic graphene oxide-functionalized citrus peel-derived bio-composite (mGOBC) was synthesized and characterized successfully, and it was proved to possess a three-dimensional (3D) porous architecture and graphitic structure. Its potential as an enrichment adsorbent was investigated using adsorption kinetics and adsorption isotherm models to establish an effective analytical method for the determination of organophosphorus pesticides (OPPs) in vegetables. The experimental results indicated that the adsorption was better fitted with the pseudo second order model and Langmuir isotherm model, and the maximum adsorption capacities for malathion and phoxim were 25.26 mg g-1 and 42.31 mg g-1, respectively. It was found that the graphitic structure of mGOBC resulted in π-π EDA (electron donor-acceptor) interaction with the benzene rings, electron-donating N, P, and S atoms in the analytes, which assisted adsorption. Subsequently, Plackett-Burman (P-B) experimental design, central composite design (CCD) and response surface methodology (RSM) were employed to develop an analytical method based on the mGOBC adsorbent. Under optimal conditions, the developed method is accurate and precise. The novel synthesized mGOBC can efficiently achieve removal and trace determination of harmful OPPs.
Topics: Adsorption; Citrus; Graphite; Magnetic Phenomena; Malathion; Organophosphorus Compounds; Organothiophosphorus Compounds; Pesticides; Research Design; Water Pollutants, Chemical
PubMed: 34110335
DOI: 10.1039/d1ay00498k -
Ecotoxicology and Environmental Safety Nov 2023Pesticide resistance inflicts significant economic losses on a global scale each year. To address this pressing issue, substantial efforts have been dedicated to...
Pesticide resistance inflicts significant economic losses on a global scale each year. To address this pressing issue, substantial efforts have been dedicated to unraveling the resistance mechanisms, particularly the newly discovered microbiota-derived pesticide resistance in recent decades. Previous research has predominantly focused on investigating microbiota-derived pesticide resistance from the perspective of the pest host, associated microbes, and their interactions. However, a gap remains in the quantification of the contribution by the pest host and associated microbes to this resistance. In this study, we investigated the toxicity of phoxim by examining one resistant and one sensitive Delia antiqua strain. We also explored the critical role of associated microbiota and host in conferring phoxim resistance. In addition, we used metaproteomics to compare the proteomic profile of the two D. antiqua strains. Lastly, we investigated the activity of detoxification enzymes in D. antiqua larvae and phoxim-degrading gut microbes, and assessed their respective contributions to phoxim resistance in D. antiqua. The results revealed contributions by D. antiqua and its gut bacteria to phoxim resistance. Metaproteomics showed that the two D. antiqua strains expressed different protein profiles. Detoxifying enzymes including Glutathione S-transferases, carboxylesterases, Superoxide Dismutase, Glutathione Peroxidase, and esterase B1 were overexpressed in the resistant strain and dominated in differentially expressed insect proteins. In addition, organophosphorus hydrolases combined with a group of ABC type transporters were overexpressed in the gut microbiota of resistant D. antiqua compared to the sensitive strain. 85.2% variation of the larval mortality resulting from phoxim treatment could be attributed to the combined effects of proteins from both from gut bacteria and D. antiqua, while the individual contribution of proteins from gut bacteria or D. antiqua alone accounted for less than 10% of the variation in larval mortality caused by phoxim. The activity of the overexpressed insect enzymes and the phoxim-degrading activity of gut bacteria in resistant D. antiqua larvae were further confirmed. This work enhances our understanding of microbiota-derived pesticide resistance and illuminates new strategies for controlling pesticide resistance in the context of insect-microbe mutualism.
Topics: Animals; Gastrointestinal Microbiome; Onions; Proteomics; ATP-Binding Cassette Transporters; Aryldialkylphosphatase; Larva; Pesticides
PubMed: 37913580
DOI: 10.1016/j.ecoenv.2023.115649 -
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 -
Protective effects of pretreatment with Fe, Cu, and Rb on phoxim poisoning in silkworm, Bombyx mori.Journal of Trace Elements in Medicine... Dec 2021Phoxim is a widely used organophosphorus pesticide in agriculture. People are paying more and more attention to its toxicity. At present, there is no appropriate way to...
BACKGROUND
Phoxim is a widely used organophosphorus pesticide in agriculture. People are paying more and more attention to its toxicity. At present, there is no appropriate way to solve the phoxim poisoning of silkworm, which severely affected the development of sericulture. Fe, Cu, Rb exerted their biological effects through various forms in vivo.
METHODS
To evaluate the effect of Fe/Cu/Rb on phoxim poisoning in silkworm, Bombyx mori were treated with fresh mulberry leaves soaked in 2.5 mg/L phoxim for 2 min with 50 mg/L FeCl, 150 mg/L CuCl, or 0.5 mg/L RbCl from 5 days of the fifth-instar silkworm.
RESULTS
Fe, Cu, and Rb pretreatments significantly inhibited the phoxim-induced reduction of survival rate and alleviated the phoxim-induced poisoning symptoms. The protective effects of Fe, Cu, and Rb on phoxim poisoning might be due to their enhancement of superoxide dismutase (SOD), catalase (CAT), and carboxylesterase (CarE) in the hemolymph and fat body of silkworm. This enhancement might reduce reactive oxygen species (ROS) accumulation and oxidative stress (OS) caused by phoxim poisoning. Thereby it reduced the damage to silkworm tissues and cells.
CONCLUSIONS
These results showed that Fe, Cu, and Rb treatments protected the silkworm from phoxim poisoning by directly enhancing the activity of SOD, CAT, and CarE enzymes and reducing oxidative stress, but not dependent on the high expression of CYP genes. The use of Fe, Cu, and Rb to enhance the activity of SOD, CAT, and CarE enzymes may be an underlying effective way to solve phoxim poisoning in the silkworm industry.
Topics: Animals; Bombyx; Insecticides; Organophosphorus Compounds; Organothiophosphorus Compounds; Pesticides; Superoxide Dismutase
PubMed: 34425455
DOI: 10.1016/j.jtemb.2021.126844 -
Pesticide Biochemistry and Physiology Feb 2022Glyphodes pyloalis Walker is a destructive pest on mulberry trees and poses a significant threat to the sericultural industry in China. Phoxim and chlorfenapyr are two...
Glyphodes pyloalis Walker is a destructive pest on mulberry trees and poses a significant threat to the sericultural industry in China. Phoxim and chlorfenapyr are two commonly used insecticides in mulberry fields. Glutathione-S-transferases (GSTs) comprise a multifunctional protein superfamily that plays important roles in the detoxification of insecticides and xenobiotic compounds in insects. However, whether GSTs participate in the tolerance of phoxim and chlorfenapyr in G. pyloalis is still unknown. To better understand the mechanism of insecticide tolerance in G. pyloalis, the enzymatic activity of GSTs was evaluated under phoxim and chlorfenapyr exposure, respectively. GST enzyme activity was significantly increased after 12, 36 and 48 h of phoxim treatment and 12, 24, 36 and 48 h of chlorfenapyr treatment. Subsequently, eighteen GST genes were identified from the larvae transcriptome of G. pyloalis. Among these, ten GpGSTs had GSH-binding sites and fifteen GpGSTs had variable hydrophobic substrate-binding sites. The expression levels of Delta-GpGST and Epsilon-GpGST genes were significantly influenced by phoxim and chlorfenapyr treatment, and by the time post insecticide application. Furthermore, after silencing GpGST-E4, the mortality rate of G. pyloalis larvae was increased when they were exposed to chlorfenapyr, but it did not significantly alter when the larvae were exposed to phoxim. Our results indicated the vital roles of GpGSTs in the tolerance of insecticides and this action depends on the categories of insecticides. The present study provides a theoretical basis for elucidating insecticide susceptibility and promotes functional research on GST genes in G. pyloalis.
Topics: Animals; Glutathione; Insecticides; Morus; Moths; Organothiophosphorus Compounds; Pyrethrins; Transferases
PubMed: 35082028
DOI: 10.1016/j.pestbp.2021.105004 -
Chemosphere Nov 2022Although pesticides commonly exist as combinations in real-life situations of the aquatic ecosystem, the impact of the toxicity of their mixtures has remained largely...
Although pesticides commonly exist as combinations in real-life situations of the aquatic ecosystem, the impact of the toxicity of their mixtures has remained largely unclear. In this study, we investigated the combined effects of two neurotoxic pesticides, including one organophosphate insecticide phoxim (PHO) and one pyrethroid insecticide lambda-cyhalothrin (LCY), on the embryos of the small yellow croaker (Larimichthys polyactis), and their potential pathways. LCY exhibited higher toxicity relative to PHO, with a 72-h LC value of 0.0074 mg a.i. L, while the corresponding value for PHO was 0.12 mg a.i. L. The mixture of PHO and LCY exerted a synergistic effect on the embryos of L. polyactis. The activities of antioxidant enzyme CAT and apoptotic enzyme caspase 3 were substantially changed in most single and combined exposure groups relative to the baseline value. Under both single and combined exposures, more significant changes were found in the mRNA expression of five genes, including the immunosuppression gene ngln2, the apoptosis gene P53, the endocrine system gene cyp19a1b, as well as neurodevelopment genes of ap and acp2, relative to the baseline value. Furthermore, the non-target metabolomic analysis demonstrated that hundreds of differential metabolites, including two bile acids (taurodeoxycholic acid and tauroursodeoxycholic acid), were significantly increased in the exposure groups. The bile acids were closely associated with the gut microbiota, and 16S rRNA sequencing results demonstrated dysfunction of the gut microbiota after exposure, especially in the combined exposure group. Our findings indicated that there might be a potential risk connected to the co-occurrence of these two pesticides in aquatic vertebrates. Consequently, future ecological risk assessments should incorporate synergistic mixtures because the current risk assessments do not consider them.
Topics: Animals; Antioxidants; Bile Acids and Salts; Caspase 3; Ecosystem; Insecticides; Nitriles; Organophosphates; Organothiophosphorus Compounds; Perciformes; Pesticides; Pyrethrins; RNA, Messenger; RNA, Ribosomal, 16S; Taurodeoxycholic Acid; Tumor Suppressor Protein p53
PubMed: 36037960
DOI: 10.1016/j.chemosphere.2022.136203 -
Ecotoxicology and Environmental Safety Feb 2020Organophosphate pesticides are widely applied worldwide for agricultural purposes, and their exposures often result in adverse effects on Bombyx mori. The insect gut is...
Organophosphate pesticides are widely applied worldwide for agricultural purposes, and their exposures often result in adverse effects on Bombyx mori. The insect gut is a complicated ecosystem inhabited by a large number of microbes that play important roles in insect physiology and behavior. Recent studies have reported that alteration of their microbiota due to stressful conditions or environmental changes has been linked to a compromised health status and a susceptibility to diseases. In the present study, we aimed to assess the effects of phoxim exposure on intestinal microbes in silkworms. The results showed that phoxim exposure increased the bacterial community evenness and altered the structure of gut microbiota in silkworm larvae. The abundances of several genera, such as Methylobacterium and Aurantimonadaceae, in phoxim-treated larval guts were significantly reduced compared with the HO-treated group, whereas the abundances of non-dominant bacteria, such as Staphylococcus, were significantly increased. Moreover, phoxim inhibited the expressions of antimicrobial peptides (AMPs) at the mRNA level and enhanced the pathogenesis of Enterobacter cloacae (E. cloacae) against silkworm larvae, suggesting that the immune system was inhibited after phoxim exposure. Therefore, the gut microbial community shifts were apparent after phoxim exposure. The compositional and structural changes of intestinal microbes caused by phoxim exposure might affect the normal function of the intestinal tract of silkworm. These results highlighted the importance of the gut bacterial community when investigating the mechanisms of midgut injury after pesticide exposure in Bombyx mori.
Topics: Animals; Antimicrobial Cationic Peptides; Bacteria; Bombyx; Gastrointestinal Microbiome; Gene Expression; Insect Proteins; Insecticides; Intestines; Larva; Organothiophosphorus Compounds
PubMed: 31796255
DOI: 10.1016/j.ecoenv.2019.110011 -
Pest Management Science Dec 2021Spodoptera litura is an important agricultural pest and has developed serious resistance to multiple insecticides. The resistance level to several insecticides is...
BACKGROUND
Spodoptera litura is an important agricultural pest and has developed serious resistance to multiple insecticides. The resistance level to several insecticides is reported to be unstable, but the mechanism is less reported.
RESULTS
Chlorpyrifos and phoxim resistance level in a field-collected population of S. litura declined continuously from the first to the tenth generation and remained stable at the 11th and 12th generations without insecticide exposure. Synergist experiment showed that diethyl maleate and piperonyl butoxide significantly increased mortality to chlorpyrifos and phoxim in the first and sixth generations, but not in the 12th generation. The expression of 31 identified glutathione S-transferase (GST) genes in the third-instar larvae of S. litura in the first, sixth and 12th generations was determined, and eight genes were seen to decrease significantly in the sixth and 12th generations compared with the first generation. SlGSTe9 was selected for further functional study as it had higher abundance and significantly higher expression in the chlorpyrifos-resistant population than in the susceptible population. The recombinant protein of SlGSTE9 showed metabolism activity to chlorpyrifos in vitro and in Escherichia coli, but not to phoxim. Silencing of SlGSTe9 increased the cumulative mortality to chlorpyrifos significantly. SlGSTE9 also showed antioxidant activity to cumene hydroperoxide.
CONCLUSION
Our results suggest that SlGSTe9 is directly involved in chlorpyrifos resistance stability, but not in phoxim. SlGSTE9 may also participate in insecticides resistance by relieving the oxidase stress induced by insecticides. © 2021 Society of Chemical Industry.
Topics: Animals; Chlorpyrifos; Insecticide Resistance; Insecticides; Larva; Spodoptera
PubMed: 34333855
DOI: 10.1002/ps.6582 -
Journal of Agricultural and Food... Jun 2021Glutathione -transferase genes in the epsilon group were reported to function in insecticide resistance. was validated to be overexpressed in pyrethroid- and...
Glutathione -transferase genes in the epsilon group were reported to function in insecticide resistance. was validated to be overexpressed in pyrethroid- and organophosphate-resistant populations of compared to a susceptible population. A functional study of heterologously expressed SlGSTE12 showed that and for 1-chloro-2,4-dinitrobenzene (CDNB) conjugating activity were 0.70 ± 0.18 mmol L and 90.6 ± 9.4 nmol mg min, respectively. β-Cypermethrin and cyhalothrin showed much weaker inhibition of SlGSTE12 activity to CDNB conjugation than fenvalerate, chlorpyrifos, and phoxim. analysis showed that SlGSTE12 had significant metabolism activity to fenvalerate and phoxim both and in , especially to chlorpyrifos, and slight metabolism activity toward cyhalothrin only . Silencing of by RNAi increased the mortality to fenvalerate, cyhalothrin, and chlorpyrifos significantly. SlGSTE12 also had a significant antioxidant ability against cumene hydroperoxide. Our study suggested that SlGSTE12 could metabolize phoxim, fenvalerate, cyhalothrin, and especially chlorpyrifos. SlGSTE12 might also participate in pyrethroid and organophosphate resistance by antioxidant activity.
Topics: Animals; Chlorpyrifos; Insecticide Resistance; Insecticides; Pyrethrins; Spodoptera
PubMed: 34019410
DOI: 10.1021/acs.jafc.1c00723