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To explore more efficient and less toxic antibacterial and antifungal pesticides, we utilized 2,6-difluorobenzamide as a starting material and ultimately synthesized 23 novel benzoylurea derivatives containing a pyrimidine moiety. Their structures were characterized and confirmed by 1H NMR, 13C NMR, 19F NMR, and HRMS. The bioassay results demonstrated that some of the title compounds exhibited moderate to good in vitro antifungal activities against Botrytis cinerea in cucumber, Botrytis cinerea in tobacco, Botrytis cinerea in blueberry, Phomopsis sp., and Rhizoctonia solani. Notably, compounds 4j and 4l displayed EC50 values of 6.72 and 5.21 μg/mL against Rhizoctonia solani, respectively, which were comparable to that of hymexazol (6.11 μg/mL). Meanwhile, at 200 and 100 concentrations, the target compounds 4a–4w exhibited lower in vitro antibacterial activities against Xanthomonas oryzae pv. oryzicola and Xanthomonas citri subsp. citri, respectively, compared to those of thiodiazole copper. Furthermore, the molecular docking simulation demonstrated that compound 4l formed hydrogen bonds with SER-17 and SER-39 of succinate dehydrogenase (SDH), providing a possible explanation for the mechanism of action between the target compounds and SDH. This study represents the first report on the antifungal and antibacterial activities of novel benzoylurea derivatives containing a pyrimidine moiety. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the physicochemical compatibility of mixtures of synthetic and botanical limonoid-based insecticides, as well as the toxicity of these associations, in the management of Spodoptera frugiperda (J.E. Smith) under laboratory and field conditions. For this, the associations of 4 commercial botanical insecticides based on neem registered in Brazil (Azamax, Agroneem, Azact CE, and Fitoneem) were tested with synthetic insecticides from the group of growth regulators (IGRs [triflumuron, lufenuron, methoxyfenozide and tebufenozide]). When mixed, all combinations caused a significant reduction in the pH of the mixture and a significant increase in electrical conductivity. However, all tested combinations showed similar stability behavior to the negative control (distilled water), which demonstrated their physicochemical compatibility. Furthermore, in laboratory and field bioassays, mixtures of IRGs with limonoid-based formulations provided satisfactory effects in the management of S. frugiperda. However, binary mixtures of insecticide Intrepid 240 SC with Azamax or Azact CE (at LC25 previously estimated) showed the highest toxicities on S. frugiperda larvae in laboratory bioassays and damage reduction caused by S. frugiperda in a 2-yr field experiments. Therefore, mixtures of IGRs with limonoid-based botanical insecticides are promising alternatives for the management of S. frugiperda and important component of integrated pest management and insect resistance management programs. [ABSTRACT FROM AUTHOR]

To explore more efficient and less toxic antibacterial and antifungal pesticides, we utilized 2,6-difluorobenzamide as a starting material and ultimately synthesized 23 novel benzoylurea derivatives containing a pyrimidine moiety. Their structures were characterized and confirmed by 1H NMR, 13C NMR, 19F NMR, and HRMS. The bioassay results demonstrated that some of the title compounds exhibited moderate to good in vitro antifungal activities against Botrytis cinerea in cucumber, Botrytis cinerea in tobacco, Botrytis cinerea in blueberry, Phomopsis sp., and Rhizoctonia solani. Notably, compounds 4j and 4l displayed EC50 values of 6.72 and 5.21 μg/mL against Rhizoctonia solani, respectively, which were comparable to that of hymexazol (6.11 μg/mL). Meanwhile, at 200 and 100 concentrations, the target compounds 4a–4w exhibited lower in vitro antibacterial activities against Xanthomonas oryzae pv. oryzicola and Xanthomonas citri subsp. citri, respectively, compared to those of thiodiazole copper. Furthermore, the molecular docking simulation demonstrated that compound 4l formed hydrogen bonds with SER-17 and SER-39 of succinate dehydrogenase (SDH), providing a possible explanation for the mechanism of action between the target compounds and SDH. This study represents the first report on the antifungal and antibacterial activities of novel benzoylurea derivatives containing a pyrimidine moiety.

To improve the quality and increase the shelf life of agricultural products, many pesticides are widely used. Although the use of pesticides in agricultural applications provides a wide range of beneficial effects, overuse of these substances results in their accumulation in soil, surface water, and foods. The analysis of pesticide residues is thus very important for the health of consumers. In this study, a combined extraction method of QuEChERS based on deep eutectic solvents and DLLME method for the extraction of Hexaflumuron, Chlorfluazuron, Flufenoxuron, Diafenthiuron, and Diflubenzuron benzoylurea pesticides from fruit samples of grape, apple, cherry, apricot, and orange and then analyzing them using high-performance liquid chromatography with diode array detector is presented. According to the results, the proposed method is simple, reliable, and inexpensive with low organic solvent consumption and has a short analysis time, and indicates good values extraction efficiency, so that under optimal conditions, limits of detection and quantification were obtained in the range of 3.3-6.5 and 11.2-22.2 ng/ml, respectively. Recovery rates and enhancement factors ranged from 52% to 88%. In actual samples, only Flufenoxuron insecticide present in one grape sample was detected at 17 0.5 ng/ml. TRANSLATE with x English Arabic Hebrew Polish Bulgarian Hindi Portuguese Catalan Hmong Daw Romanian Chinese Simplified Hungarian Russian Chinese Traditional Indonesian Slovak Czech Italian Slovenian Danish Japanese Spanish Dutch Klingon Swedish English Korean Thai Estonian Latvian Turkish Finnish Lithuanian Ukrainian French Malay Urdu German Maltese Vietnamese Greek Norwegian Welsh Haitian Creole Persian // TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back // TRANSLATE with x English Arabic Hebrew Polish Bulgarian Hindi Portuguese Catalan Hmong Daw Romanian Chinese Simplified Hungarian Russian Chinese Traditional Indonesian Slovak Czech Italian Slovenian Danish Japanese Spanish Dutch Klingon Swedish English Korean Thai Estonian Latvian Turkish Finnish Lithuanian Ukrainian French Malay Urdu German Maltese Vietnamese Greek Norwegian Welsh Haitian Creole Persian // TRANSLATE with COPY THE URL BELOW Back EMBED THE SNIPPET BELOW IN YOUR SITE Enable collaborative features and customize widget: Bing Webmaster Portal Back //

A facile and general transition‐metal‐free access to 1‐substituted‐4‐quinazolinones 2 has been achieved based on the proline‐mediated cyclization of carbamoylbenzamides 1 in the presence of potassium t‐butoxides in DMSO at 100 °C within several hours. The gram‐scale synthesis of 1‐phenyl‐4‐quinazolinone 2 a has also been achieved without the loss of efficiency. The one‐pot synthesis of 1‐phenyl‐4‐quinazolinone 2 a has proven to be possible starting from 2‐bromobenzamide and phenylisocyanate in an acceptable yield. The present reactions were assumed to proceed through radical intermediates as the major path and also the SNAr route as a minor path based on several control experiments. [ABSTRACT FROM AUTHOR]

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The benzoylurea chitin synthesis inhibitor teflubenzuron, widely used against sea lice in North Atlantic aquaculture, may pose an environmental threat to non‐targeted crustaceans. In this experiment, laboratory acclimated pink shrimp (Pandalus montagui), a species found in fjords with Atlantic salmon farming, were exposed to dietary teflubenzuron for 46 days (control; low dose: 0.01 μg/g; high dose: 0.1 μg/g). The exposure doses represent 0.1% and 1% of a standard treatment dose for Atlantic salmon. Mortality and prevalence of deformities, pharmacokinetics, oxidative stress and transcriptomic and metabolomic profiling were used to assess the response to teflubenzuron exposure. Mortality in the high‐dose group was 25% (five of 20 individuals). No control or low‐dose group shrimps died. Phenotypic responses,i.e., leg deformities (0 control, 6 low, 8 high) and cloudy eyes (0 control, 3 low, 7 high), were observed in some surviving shrimps (control n = 15, low n = 17, high n = 15). Accumulated levels of teflubenzuron in shrimps from the high‐dose group ranged from 4.7 to 369 ng/g wet weight. Transcriptomic profiling showed very few significantly altered genes in the exposed shrimps. Teflubenzuron‐induced changes to the metabolome pointed to well‐known effects of benzoylurea agents, with reduced levels of N‐acetylglucosamine indicating an effect on chitin synthesis. The metabolomic profiling showed that teflubenzuron exposure was associated with reduced energy metabolism. Some metabolites pointed to increased necrosis and/or bacterial overgrowth in the teflubenzuron‐exposed shrimps. In conclusion, this study shows that teflubenzuron causes phenotypic effects in P. montagui exposed to 0.1% of the treatment dose given to Atlantic salmon. Pink shrimp (Pandalus montagui) was exposed to the anti‐sea‐lice drug teflubenzuron for 46 days. Mortality, deformities and accumulation were monitored, and transcriptomic and metabolomic profiling determined sublethal mode of action. Exposure to 1% of a standard daily treatment dose for Atlantic salmon resulted in 25% mortality, deformities and variable degree of accumulation. Metabolomics showed that teflubenzuron reduced energy metabolism and affected chitin synthesis. The study shows that teflubenzuron might harm P. montagui near fish farms at environmentally realistic concentrations. [ABSTRACT FROM AUTHOR]

Abstract Animals with exoskeleton need to molt to grow and develop. Molting is well described in some arthropods especially insects. Chitin is a polymer of N -acetylglucosamine, and one of the major components of the exoskeleton of arthropods. Chitin is synthesized and degraded by a series of enzymes during the molting cycle. However, the presence and function of these enzymes are largely unknown in copepods such as the ectoparasite salmon louse (Lepeophtheirus salmonis) a major pest in salmonid aquaculture. Here we describe six genes found in the L. salmonis genome (LsCHS1, LsCHS2, LsGFAT, LsGNA1, LsAGM, and LsUAP) with high homology to enzymes in the chitin synthesis pathway. The transcription profiles of these enzymes together with three chitinases enzymes (LsChi1, LsChi2, and LsChi4), which have been characterized before, were examined during the synthesis of a new exoskeleton and revealed a dynamical expression concurrent with the morphological changes during the molt cycle. Further understanding of chitin metabolism and its regulation may prove useful tool to develop new pesticides. Highlights • Identification of components of chitin metabolism in the copepod Lepeophtheirus salmonis. • Phylogenetic analysis of protein involved in chitin production and degradation. • Transcriptional profiling of key transcripts during instar maturation and cuticle formation. [ABSTRACT FROM AUTHOR]

Highlights • AChE from brain of H. littorale were physicochemical and kinetically characterized. • Selective inhibitors showed AChE as the main ChE in H. littorale brain. • The enzyme was exposed to carbamate, organophosphorus, benzoylurea and juvenile hormone analogue pesticides as well as ions. • The first report on the inhibition of brain AChE in the Siluriformes group by novaluron and pyriproxyfen. • Dichlorvos IC 20 was below the concentrations allowed by current legislation whereas mercury was the strongest inhibitory ion. Abstract Acetylcholinesterase (AChE; EC 3.1.1.7) is a serine hydrolase, whose main function is to modulate neurotransmission at cholinergic synapses. It is, therefore, the primary target of some pesticides and heavy metals. Its inhibition in aquatic organisms has been used as an indicator of the presence of these pollutants in water bodies. The present study aimed to characterize physicochemical and kinetic parameters of brain AChE in the benthic fish Hoplosternum littorale and to analyze the in vitro effects of pesticides (dichlorvos, diazinon, chlorpyrifos, parathion-methyl, temephos, carbaryl, carbofuran, aldicarb, diflubenzuron, novaluron and pyriproxyfen) and metal ions (As3+, Cd2+, Cu2+, Fe2+, Mn2+, Mg2+, K+, Pb2+, Hg2+, Zn2+) investigating the potential of this enzyme as environmental biomarker based on current regulations. Specific substrates and inhibitors have indicated AChE to be the predominant cholinesterase (ChE) in the brain of H. littorale. Peak activity was observed at pH 8.0 and 30 °C. The enzymatic activity is otherwise moderately thermostable (≈ 50% activity at 45 °C). The enzyme can reduce the activation energy of acetylthiocholine hydrolysis reaction to 8.34 kcal mol−1 while reaching a rate enhancement of 106. Among the pesticides under study, dichlorvos presented an IC 50 value below the maximum concentrations allowed by legislation. This study presents the first report on the inhibition of brain AChE activity from Siluriformes by the pesticides novaluron and pyriproxyfen. Mercury ion also exerted a strong inhibitory effect on its enzymatic activity. The H. littorale enzyme thus has the potential to function as an in vitro biomarker for the presence of the pesticide dichlorvos as well as mercury in areas of mining and industrial discharge. [ABSTRACT FROM AUTHOR]

Highlights • DAAQ-TFP was prepared as adsorbent for extraction of BUs. • DAAQ-TFP has excellent extraction performance and adsorption capacity. • SPE-HPLC-UV was developed for the determination of BUs with low LODs. Abstract A covalent organic framework (named as DAAQ-TFP) was prepared via a fast, environmentally-friendly, and easy-to-perform grinding method with 2,6-diaminoanthraquinone (DAAQ) and 1,3,5-triformylphloroglucinol (TFP) as building blocks. The DAAQ-TFP possesses large surface area, high porosity, good thermochemical stability, abundant O atoms and N-H groups, which render it great potential as sorbent for some compounds. It was employed as adsorbent to extract benzoylurea insecticides (BUs) from environmental water, juice, fruit and vegetables samples, followed by their determination with high-performance liquid chromatography (HPLC). The DAAQ-TFP showed a high adsorption capacity for BUs, and the presented method provided a very low limits of detection and high method recoveries. To explore its application potential and also to clarify the possible adsorption mechanisms of the DAAQ-TFP toward BUs, it was tested to extract different types of compounds, proving that the DAAQ-TFP can serve as a superior adsorbent, and adsorption mechanism is mainly based on the π-π stacking and H bonding. [ABSTRACT FROM AUTHOR]

A pretreatment method using hyperbranched polyester (HBPE) composite as sorbent based on dispersive micro-solid-phase (d-μ-SPE) extraction preceding high-performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in water samples. Parameters that may influence the extraction efficiency, such as the diameter and the amount of the sorbent, extraction and desorption time and the pH value of the solution, were investigated and optimized using batch and column procedures. Under optimized conditions, good linearity was obtained for all of the tested compounds, with r values of at least 0.9924. The linearity of the method was determined in the range of 1–25 000 μg L−1. The limits of detection (LODs) ranged from 0.024 to 0.068 μg L−1. The recoveries of the four benzoylurea insecticides in water samples increased from 85.50–96.12%. The results confirmed the possibility of using hyperbranched polyester in the determination of relatively hydrophobic trace pesticides residues. Finally, the proposed method was applied to the determination of BUs in water samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: A magnetic polytriphenylamine porous organic polymer was prepared through simple self‐polycondensation of triphenylamine followed by coprecipitation with Fe2+ and Fe3+. It was applied as a magnetic adsorbent for the extraction of six benzoylurea insecticides from tomato, cucumber, and watermelon samples before their high‐performance liquid chromatography and mass spectral detection. Under the optimized experimental conditions, the established method gave a low limit of detection ranging from 0.05 to 0.1 ng/g and a good linear response ranging from 0.2 to 40 ng/g with coefficients of determination >0.99. The method recoveries for spiked analytes at the concentrations of 3 and 15 ng/g in real samples were in the range of 87.7–106.7% with the relative standard deviations <6.4%. The results indicated that it had a good adsorption capability toward the target analytes due to the π‐stacking and hydrogen bonding interactions. The polymer material showed great potential in the efficient extraction of organic compounds from real samples with complex matrixes. [ABSTRACT FROM AUTHOR]

Drug resistance in the salmon louse Lepeophtheirus salmonis is a global issue for Atlantic salmon aquaculture. Multiple resistance has been described across most available compound classes with the exception of the benzoylureas. To target this gap in effective management of L. salmonis and other species of sea lice (e.g. Caligus spp.), Elanco Animal Health is developing an in-feed treatment containing lufenuron (a benzoylurea) to be administered prior to seawater transfer of salmon smolts and to provide long-term protection of salmon against sea lice infestations. Benzoylureas disrupt chitin synthesis, formation, and deposition during all moulting events. However, the mechanism(s) of action are not yet fully understood and most research completed to date has focused on insects. We exposed the first parasitic stage of L. salmonis to 700 ppb lufenuron for three hours and observed over 90% reduction in survival to the chalimus II life stage on the host, as compared to vehicle controls. This agrees with a follow up in vivo administration study on the host, which showed >95% reduction by the chalimus I stage. Transcriptomic responses of salmon lice exposed to lufenuron included genes related to moulting, epithelial differentiation, solute transport, and general developmental processes. Global metabolite profiles also suggest that membrane stability and fluidity is impacted in treated lice. These molecular signals are likely the underpinnings of an abnormal moulting process and cuticle formation observed ultrastructurally using transmission electron microscopy. Treated nauplii-staged lice exhibited multiple abnormalities in the integument, suggesting that the coordinated assembly of the epi- and procuticle is impaired. In all cases, treatment with lufenuron had rapid impacts on L. salmonis development. We describe multiple experiments to characterize the efficacy of lufenuron on eggs, larvae, and parasitic stages of L. salmonis , and provide the most comprehensive assessment of the physiological responses of a marine arthropod to a benzoylurea chemical. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Rice sheath blight is a globally important rice disease. Unfortunately, this critical disease has not been effectively controlled, and the intensive and continuous use of the same fungicide might increase the risk of resistance development in the pathogen. To discover new active agents against rice sheath blight, in this study, three series of β‐carboline urea, benzoylurea and benzoylthiourea derivatives were designed, synthesized and evaluated for in vitro and in vivo fungicidal activity against Rhizoctonia solani. RESULTS: All these compounds (EC50: 0.131–1.227 mmol L−1) exhibited better fungicidal activity than harmine itself (EC50: 2.453 mmol L−1). Significantly, compound 17c (EC50: 0.131 mmol L−1) displayed the best efficacy in vitro and superior fungicidal activity compared with validamycin A (EC50: 0.397 mmol L−1). Moreover, the in vivo bioassay also indicated that compound 17c could be effective for the control of rice sheath blight. CONCLUSION: Based on the bioassay result and quantitative structure–activity relationship (QSAR) information, structure modification in β‐carboline warrants further investigation and its benzoylurea derivative 17c, which showed the best fungicidal activities, could emerge as a potential fungicide against rice sheath blight. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In the present study, a convenient, low-cost, sensitive and environmentally friendly method for the determination of four benzoylurea insecticides (BUs) in water and tea beverage samples was developed. The alkalized luffa sponge fibers (AL) were modified by the ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C16MIM]Br) through physisorption and used as the sorbent of dispersive solid-phase extraction (DSPE). The sorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The retained analytes were eluted using 200 μL of methanol and then quantified by high performance liquid chromatography-ultraviolet detection (HPLC-UVD). The influences of extraction parameters of [C16MIM]Br-AL-DSPE on the BUs were thoroughly studied. Under the optimal conditions, good linearity was observed over the concentration range of 1–500 ng mL−1, with coefficients of determination greater than 0.99. The limits of detection (LODs) of the developed method were 0.14–0.21 ng mL−1 in water and 0.19–0.23 ng mL−1 in tea beverage samples. Satisfactory recoveries were achieved in the range of 72.8–89.3%, with relative standard deviations lower than 10%. Finally, the established [C16MIM]Br-AL-DSPE-HPLC-UVD method was successfully applied for the determination of BU residues in environmental water and tea beverage samples. [ABSTRACT FROM AUTHOR]

A covalent organic framework named TpAzo was successfully fabricated by a simple and environmentally friendly mechanochemical grinding method based on the Schiff base aldehyde-amine condensation reaction between 1,3,5-triformylphloroglucinol (Tp) and 4,4′-azodianiline (Azo), with p -toluene sulphonic acid as a molecular organizer. The TpAzo was characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, nitrogen adsorption-desorption isotherms, and thermogravimetric analysis. The TpAzo possessed a sheet-like morphology, rich porosity and high thermal stability. The extraction performance of the TpAzo was investigated by using it as the solid phase extraction adsorbent for the extraction of benzoylurea insecticides (BUs) from juice, tomato and white radish samples prior to high performance liquid chromatographic analysis. Under the optimal conditions, a good linearity for the BUs existed in the range of 1.0–160.0 ng mL −1 for juice sample and 0.5–80.0 ng g −1 for tomato and white radish samples with the correlation coefficients of 0.9956–0.9999. The limits of detection for the analytes were 0.1–0.2 ng mL −1 for juice sample and 0.05–0.1 ng g −1 for tomato and white radish samples. The method recoveries for the analytes fell in the range of 84.1%–108.6%. The adsorption mechanism of the TpAzo was investigated by using it to extract different types of organic compounds, including phthalates, phenylurea herbicides and carbamate insecticides. The results showed that the π-stacking and hydrophobic interactions between the TpAzo and the analytes played an important role for the adsorption. [ABSTRACT FROM AUTHOR]

Dermal exposure is regarded as a potentially significant but understudied route for pesticides uptake in terrestrial reptiles. In this study, a native Chinese lizard was exposed to control, diflubenzuron or flufenoxuron contaminated soil (1.5 mg kg −1 ) for 35 days. Tissue distribution, liver lesions, thyroid hormone levels and transcription of most target genes were examined. The half-lives of diflubenzuron and flufenoxuron in the soil were 118.9 and 231.8 days, respectively. The accumulation of flufenoxuron in the liver, brain, kidney, heart, plasma and skin (1.4–35.4 mg kg −1 ) were higher than that of diflubenzuron (0–1.7 mg kg −1 ) at all time points. The skin permeability factor of flufenoxuron was more than 20-fold greater than that of diflubenzuron at the end of exposure. However, the liver was more vulnerable in the diflubenzuron exposure group. The alterations of triiodothyronine (T3) and thyroxine (T4) level after diflubenzuron or flufenoxuron exposure were accompanied with the changes in the transcription of target genes involved not only in hypothalamus-pituitary-thyroid (HPT) axis ( sult , dio2 , trα and udp ) but also in metabolism system ( cyp1a and ahr ). These results indicated that flufenoxuron produced greater body burdens to lizards through dermal exposure, whereas both diflubenzuron and flufenoxuron have the potential to disturb metabolism and thyroid endocrine system. [ABSTRACT FROM AUTHOR]

Abstract: The morphometric analysis of parasitoids may contribute to biological control programs by providing information on development of insects and relationships among sizes of morphological characters. Furthermore, it can infer about the impact of insecticides on morphological characters and fitness. We evaluate the morphometry, allometry, and fluctuating asymmetry of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) with and without influence of the growth‐regulating insecticides teflubenzuron and lufenuron. Trichogramma pretiosum had significantly larger wings and tibiae in treatments with insecticides. We found no effects of insecticides on asymmetry in T. pretiosum and conclude that this insect is very close to isometry. This study emphasizes the importance of evaluating the size of parasitoids destined to biological control programs. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a magnetic β‐cyclodextrin polymer was successfully prepared and used as an adsorbent for the magnetic solid‐phase extraction of six benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, flufenoxuron, and chlorfluazuron) from honey, tomato, and environmental water samples. The influence of the main experimental conditions on the extraction was studied. Under the optimized conditions, the β‐cyclodextrin polymer@Fe3O4 showed an excellent extraction performance for the benzoylurea insecticides. A good linearity was obtained for the analytes in the range of 3.0–800 ng/g for honey samples, 0.3–160 ng/g for tomato samples, and 0.1–80.0 ng/mL for water samples, with the correlation coefficients above 0.9998. Satisfactory repeatabilities were achieved, with the relative standard deviations less than 5.7%. The limits of detection (S/N = 3) of the method for the benzoylurea insecticides were 0.2–0.8 ng/g for honey samples, 0.04–0.10 ng/g for tomato samples, and 0.02–0.05 ng /mL for water samples. The method was successfully used for the determination of the six benzoylurea insecticides residues in honey, tomato, and environmental water samples with a satisfactory result. [ABSTRACT FROM AUTHOR]

Enzyme biomarkers from several aquatic organisms have been used for assessing the exposure to contaminants at sublethal levels. Amongst them, the cholinesterases are commonly extracted from several organisms to evaluate/measure organophosphate and carbamate neurotoxic effects. Acetylcholinesterase (AChE; EC 3.1.1.7) is an enzyme of the group of serine esterases that acts on the hydrolysis of the neurotransmitter acetylcholine allowing the intermittence of the nerve impulses responsible for the neuronal communication. This enzyme is the main target for the action of some pesticides and the inhibition of its activity in bivalve mollusks may be used as biomarker due to their filter-feeding habit. In this context, the present study aimed to characterize physicochemical and kinetic parameters of the AChE extracted from gills and viscera of the oyster Crassostrea rhizophorae and investigate the in vitro effect of pesticides (dichlorvos, diazinon, chlorpyrifos, methyl-parathion, temephos, carbaryl, carbofuran, aldicarb, diflubenzuron and novaluron) in search for assessing its potential as biomarker. Specific substrates and inhibitors evidenced the predominance of AChE in both tissues. The optimum pH found for gills and viscera AChE were 8.0 and 8.5, respectively. The maximum peak of activity occurred at 70 °C for gill AChE and 75 °C for viscera AChE. The enzymes of both tissues presented remarkable thermostability. The Michaelis-Menten constant for both enzymes were 1.32 ± 0.20 mM for gills and 0.43 ± 0.12 mM for viscera. The V max values for gills and viscera were 53.57 ± 1.72 and 27.71 ± 1.15 mU/mg, respectively. The enzymes were able to reduce the activation energy to 9.75 kcal mol −1 (gills) and 11.87 kcal mol −1 (viscera) obtaining rate enhancements of 3.57 × 10 5 and 1.01 × 10 4 , respectively, in relation to non-catalyzed reactions. Among the pesticides under study, the carbamates carbaryl and carbofuran exerted the strongest inhibitory effects on the enzyme activity achieving important degrees of inhibition at concentrations below national and international current regulations. The first observation of the effects of benzoylurea pesticides (diflubenzuron and novaluron) on AChE from mollusks is reported here. The gills AChE of C . rhizophorae showed potential to be specific biomarker for the carbamate carbaryl while the viscera AChE showed it for carbofuran. According to their features, these enzymes may be proposed as promising tools for estuarine monitoring as well as biocomponent of biosensor devices. [ABSTRACT FROM AUTHOR]

Abstract According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at the European level for the pesticide active substance lufenuron. To assess the occurrence of lufenuron residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC, the MRLs established by the Codex Alimentarius Commission as well as the authorisations reported by the Member States (including the supporting residues data) and import tolerances. Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers.

We present a novel dispersive liquid-liquid microextraction method based on the solidification of deep eutectic solvent coupled with high-performance liquid chromatography with a variable-wavelength detection for the detection of five benzoylureas in real water samples. In this work, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-dodecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. Parameters that significantly affect extraction efficiency were optimized by the one-factor-at-a-time approach. Under optimal conditions, the recoveries of five target compounds were obtained ranging from 87.39 to 98.05% with correlation coefficients ranging from 0.9994 to 0.9997 for pure water. The limits of detection were in the range of 0.09-0.16 μg/L. The enrichment factors were in the range of 171-188. Linearities were achieved in the range of 0.5-500 μg/L. The proposed method was successfully applied to determine benzoylureas in environmental water samples with a satisfactory recovery of approximately 81.38-97.67%. [ABSTRACT FROM AUTHOR]

Benzoylurea pesticides (BPUs) are widely used to control the locust, but the toxicokinetics and hepatotoxicity of BPUs in lizards have not been investigated. In this study, the tissue distribution, metabolism and liver toxicity of diflubenzuron and flufenoxuron were assessed in the Eremias argus following a single oral exposure. Diflubenzuron preferred to accumulate in the fat and brain (>1.0 mg kg −1 ) and was rapidly eliminate in other tissues. In the liver, 4-chloroaniline was one of diflubenzuron metabolites, although with a concentration less than 0.05% of the accumulated diflubenzuron. No significant difference was observed in the liver histopathology between the control and diflubenzuron exposure group. The expressions of Cyp1a and Ahr gene which control the cell apoptosis were also equal to the control level. After flufenoxuron exposure, biomodal phenomenon was observed in the liver, skin, brain, gonad, kidney, heart and blood circulation was an important route for the flufenoxuron penetration. The concentrations of flufenoxuron in all tissues were greater than 1.0 mg kg −1 at 168 h. The excretion of flufenoxuron in the faeces was 1.5 fold higher than diflubenzuron. The hepatocytes in the flufenoxuron treated group showed vacuolation of cytoplasm and decreased nucleus. In addition, the Cyp1a and Ahr genes were significantly up-regulated in the flufenoxuron exposure group. These results suggested that the higher hepatotoxicity of flufenoxuron may be attributed to the higher residual level in the lizard tissues and the Cyp1a and Ahr genes can serve as biomarkers to assess the liver toxicity. [ABSTRACT FROM AUTHOR]

We examined the susceptibility of field strains (BO-1, BO-2, TO-1, and YH-1) and one laboratory strain (H-1) of the western flower thrip, Frankliniella occidentalis, to benzoylureas. LC50 values of novaluron were determined as 0.64 ppm against laboratory strain and 2.1-130 ppm against field strains. In the presence of piperonyl butoxide, a cytochrome P450 inhibitor, the insecticidal activity of novaluron tended to be enhanced. To examine whether point mutations in chitin synthase 1 (CHS1) discovered in an etoxazole-resistant strain of Tetranychus urticae and a benzoylurea-resistant strain of Plutella xylostella exist in F. occidentalis, the nucleotide sequence of CHS1 was analyzed. We found a nonsynonymous substitution that corresponded to the location of the mutations found in T. urticae and P. xylostella in the field strains of F. occidentalis but not in the laboratory strain, indicating that this point mutation might be associated with the benzoylurea resistance exhibited by the field strains. [ABSTRACT FROM AUTHOR]

The insecticide Match® (lufenuron), one of the main insect growth regulators used in pest control, has been presented as a viable alternative against the boll weevil, Anthonomus grandis (Coleoptera: Curculionidae), by inhibiting chitin synthesis. Thus, this study aimed to examine whether Match® interferes in the synthesis of the peritrophic matrix, leading to changes in the midgut epithelium, resulting in nutritional deficiency and reflecting, thereby, in the gametogenesis process of A. grandis . Floral cotton buds were immersed in the insecticide solution (800 μL of Match® + 200 mL of distilled water) and offered to the adult insects. The midguts of the insects were evaluated after 24 and 120 h after feeding. The gonads were evaluated after 120 h. The results showed that Match®, in both evaluation periods, induced histopathological alterations such as disorganization, vacuolization and desquamation of the midgut epithelium; histochemical modifications in the distribution patterns of carbohydrates, although without quantitative changes; and a strong decrease in protein levels. No apoptosis were observed, however, there was an increase in the number of regenerative cell nests. In the testicles, a reduction in the amount of spermatozoids and reduced carbohydrate levels were observed, but no difference in protein levels. The ovarioles presented structural disorganization of follicular cells, yolk reduction and decrease in protein levels, however, no change in carbohydrates levels was noted. Therefore, it is concluded that Match® performs histopathologic and histochemical alterations in the midgut epithelium and the gonads of A. grandis adults, reflecting in the gametogenesis process, presenting itself as a promising tool in the management of this pest on cotton crops. [ABSTRACT FROM AUTHOR]

A simple, fast, effective, and environmentally friendly method, in situ solvent formation microextraction combined with magnetic dispersive micro-solid-phase extraction for the determination of four benzoylurea insecticides is presented herein for the first time. In the proposed method, 1-hexyl-3-methylimidazolium bis[(trifluoromethane)sulfonyl]imide was formed by the reaction between 1-hexyl-3-methylimidazolium chloride and lithium bis[(trifluoromethane)sulfonyl]imide and was used to extract benzoylurea insecticides. Then magnetic nanoparticles were added as carrier to retrieve and separate the ionic liquid from the sample solution. After the supernatant was removed, the ionic liquid was desorbed using acetonitrile and subsequently injected directly into a high-performance liquid chromatograph equipped with a variable wavelength detector for analysis. The main factors affecting the extraction efficiency were investigated by a one factor at a time approach. Under optimized conditions, the proposed method showed good repeatability (RSD = 2.2-4.5%) and linearity (2-300 μg/L), with correlation coefficients greater than 0.9994 and low limits of detection (0.67-1.46 μg/L). Finally, the method was successfully applied to the analysis of four benzoylurea insecticides in environmental water samples with good recoveries (73.2-85.8%). [ABSTRACT FROM AUTHOR]

A novel in-syringe dispersive liquid-liquid microextraction based on the solidification of ionic liquids (in-syringe SIL-DLLME) was coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UVD) to detect five benzoylurea insecticides (BUs) in water and tea beverage samples. In this method, the hydrophobic ionic liquid [N 8881 ][PF 6 ] was formed in situ by the metathesis reaction between [N 8881 ]Cl and the anion-exchange reagent KPF 6 to extract the target analytes. The whole extraction procedure was performed in a syringe. The solidified extractant could be separated from the aqueous phase by exposing the emulsified extraction solution to an ice bath and then easily collected by squeezing out the aqueous phase through the prepared NWPP-based needle. Various parameters affecting the extraction efficiency, such as the amount of [N 8881 ]Cl, the molar ratio of [N 8881 ]Cl to KPF 6 , salt addition, cooling time, solution temperature, sample pH and sample volume, were evaluated. Under the optimized conditions, the proposed method was validated with satisfactory results: good linearities with coefficients of determination greater than 0.99 were obtained in the range of 2–500 µg L −1 ; the limits of detection varied between 0.29 and 0.59 µg L −1 ; the recoveries of the five benzoylurea insecticides ranged from 85.93% to 90.52%; and the intra-day ( n =3) and inter-day ( n =3) relative standard deviations were less than 5.36%. Finally, the proposed method was successfully used for the determination of BUs in real water and tea beverage samples. [ABSTRACT FROM AUTHOR]

According to Article 12 of Regulation ( EC) No 396/2005, EFSA has reviewed the maximum residue levels ( MRLs) currently established at the European level for the pesticide active substance lufenuron. To assess the occurrence of lufenuron residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/ EEC, the MRLs established by the Codex Alimentarius Commission as well as the authorisations reported by the Member States (including the supporting residues data) and import tolerances. Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers. [ABSTRACT FROM AUTHOR]

Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin--an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro. [ABSTRACT FROM AUTHOR]

A pretreatment method using in-syringe dispersive liquid–liquid microextraction based on the direct solidification of ionic liquids before high performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in honey samples. The hydrophobic ionic liquid [N 4444 ][PF 6 ], formed in situ by the hydrophilic ionic liquid [N 4444 ]Cl and the ion exchange reagent KPF 6 , was used to extract the target analytes. The entire extraction procedure was performed in a syringe. The extractant was solidified at room temperature and collected using a nylon membrane filter. This technique did not require a dispersive solvent, vortex mixer, ultrasound bath, or centrifugation. The parameters affecting the extraction efficiency were investigated through an experimental design. Under the optimal conditions, the limits of detection for the four BUs varied from 0.21 to 0.42 μg L −1 in solution (2.1–4.2 μg kg −1 in honey). Good linearities were obtained in the range of 2–300 μg L −1 , with coefficients of determination greater than 0.999. The recoveries of the four BUs ranged from 80.94% to 84.59%. The intra-day ( n = 3) and inter-day ( n = 3) relative standard deviations were less than 5.08%. Finally, the proposed method was applied to the determination of BUs in commercial honey samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Lufenuron is a benzoylurea insecticide that interfere in chitin synthesis in insects. Although lufenuron is widely used in agriculture and aquaculture, rare are studies described that relates to possible toxic effects in fish. This work aimed to evaluate acute and chronic toxic effects of benzoylurea pesticide (lufenuron) on biological parameters of Colossoma macropomum (Tambaqui). In the acute test, juveniles of Tambaqui were divided into control group and five experimental groups with exposure from 0.1 to 0.9 mg/L of lufenuron for 96 h. Animals were also submitted to chronic toxicity test for four months in concentrations of 0.1 and 0.3 mg/L of lufenuron, the concentration used in the treatment of ectoparasites in fish and 50% of LC 50 96 h, respectively. The presence of hemorrhages was observed in eyes, fins and operculum of fish exposed to 0.7 and 0.9 mg/L of lufenuron. Histological analysis showed changes in the morphology of fish gills submitted to acute toxicity test, as lamellar aneurysm and blood congestion inside lamellae. Lufenuron promoted damage in fish retina as in ability to respond to stimuli in photoreceptors and in ON-bipolar cells in acute test. In chronic test, blood glucose analysis and morphometric parameters showed no significant differences (p > 0.05). In general, Tambaqui exhibited behaviors associated with stress when exposed to lufenuron. Thus, lufenuron showed several toxic effects in relation to biological parameters in Tambaqui. This concerns about the use and discard of lufenuron, and indicates the requirement of environmental actions to prevent potential contamination of aquatic biota. [ABSTRACT FROM AUTHOR]

In this study, the superparamagnetic attapulgite/Fe 3 O 4 /polyaniline (ATP/Fe 3 O 4 /PANI) nanocomposites were successfully synthesized by a one-pot method. Fe (III) was applied as both the oxidant for the oxidative polymerization of aniline and the single iron source of Fe 3 O 4 formed by the redox reaction between aniline and Fe (III). The ATP/Fe 3 O 4 /PANI was used as sorbent for magnetic dispersive solid phase extraction (MDSPE) of benzoylurea insecticides (BUs) in environmental water samples. The as-prepared nanocomposite sorbents were characterized by Fourier transform infrared spectra (FT-IR), X Ray diffraction (XRD), scanning electron microscopy(SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry. Various experimental parameters affecting the ATP/Fe 3 O 4 /PANI-based MDSPE procedure, including the composition of the nanocomposite sorbents, amount of ATP/Fe 3 O 4 /PANI nanocomposites, vortex time, pH, and desorption conditions were investigated. Under the optimal conditions, a good linearity was observed for all target analytes, with correlation coefficients (r 2 ) ranging from 0.9985 to 0.9997; the limits of detection (LOD) were in the range of 0.02–0.43 μg L −1 , and the recoveries of analytes using the proposed method ranged between 77.37% and 103.69%. The sorbents exhibited an excellent reproducibility in the range of 1.52–5.27% in extracting the five target analytes. In addition, the intra-day and inter-day precision values were found to be in the range of 0.78–6.86% and 1.66–8.41%, respectively. Finally, the proposed ATP/Fe 3 O 4 /PANI-based MDSPE method was successfully applied to analyze river water samples by rapid preconcentration of BUs. [ABSTRACT FROM AUTHOR]

A green, simple, inexpensive dispersive solid-phase microextraction method coupled with high-performance liquid chromatography was developed for rapid screening and selective recognition of benzoylurea insecticides (BUs) in honey and tea beverages. A novel adsorbent, ionic liquid (IL)-modified β-cyclodextrin/attapulgite (β-CD/ATP), was prepared by immobilizing IL on the surface of β-CD/ATP. A series of demanding extraction conditions were investigated through the experimental design. Under optimum conditions, the limits of detection for the analytes varied from 0.12 to 0.21 μg L −1 . The enrichment factors ranged from 112 to 150 folds. Linearities in the range of 5–500 ng mL −1 were achieved for four BUs, while the correlation coefficients ranged from 0.9997 to 1.0000 and the recoveries from 84.5% to 104.7%. The precision of this method for the four BUs corresponded to intra-day and inter-day RSDs% lower than 3.85%. Finally, the proposed technique was applied for the preconcentration of the BUs from real samples with satisfactory results. [ABSTRACT FROM AUTHOR]

A novel dispersive solid-phase extraction combined with vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the determination of eight benzoylurea insecticides in soil and sewage sludge samples before high-performance liquid chromatography with ultraviolet detection. The analytes were first extracted from the soil and sludge samples into acetone under optimized pretreatment conditions. Clean-up of the extract was conducted by dispersive solid-phase extraction using activated carbon as the sorbent. The vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet procedure was performed by using 1-undecanol with lower density than water as the extraction solvent, and the acetone contained in the solution also acted as dispersive solvent. Under the optimum conditions, the linearity of the method was in the range 2-500 ng/g with correlation coefficients ( r) of 0.9993-0.9999. The limits of detection were in the range of 0.08-0.56 ng/g. The relative standard deviations varied from 2.16 to 6.26% ( n = 5). The enrichment factors ranged from 104 to 118. The extraction recoveries ranged from 81.05 to 97.82% for all of the analytes. The good performance has demonstrated that the proposed methodology has a strong potential for application in the multiresidue analysis of complex matrices. [ABSTRACT FROM AUTHOR]

A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was coupled with high-performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1-dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett-Burman design and one-factor-at-a-time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5-500 μg/L, for hexaflumuron in a range of 1-500 μg/L, and for triflumuron in a range of 5-500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4-110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%. [ABSTRACT FROM AUTHOR]