Neonicotinoid insecticides have potential harm to organisms. However, there is a lack of research on its toxicological mechanisms, in vivo transport mechanisms, and other aspects. This study using a combination of the following test methods: fluorescence quenching, molecular docking, molecular dynamics, binding free energy calculation, and alanine scanning, whitch aimes to study the binding mode of cycloxaprid with human serum albumin (HSA). The results indicate that: (1) Cycloxaprid can effectively quench HSA, and their binding constants range from 0.76 × 105 L/mol to 1.57 × 105 L/mol at different temperatures with strong binding ability; (2) Cycloxaprid binds to the IIA hydrophobic cavity of HSA, with one binding site. (3) By combining free energy analysis and thermodynamic parameter calculation, the results show that the main binding forces between cycloxaprid and HSA are van der Waals forces and hydrogen bonding interactions; (4) By molecular dynamics simulation, the results show that the binding free energy is -25.90 kJ/mol, whitch formed a relatively stable complex; (5) The alanine mutation scan results showed that the amino acid residue Gln459 is a key amino acid that binds to cycloxaprid and HSA. This research can provide a theoretical basis for elucidating the toxicology mechanism of epoxidizine in the human body.
Hydraulic nozzles are widely used among many kinds of spray nozzles due to its large atomization volume, energy-efficient, simple structure, economical and practical. It’s of great importance to study the atomization and deposition characteristics of hydraulic nozzles for optimizing pesticide application performance. In order to determine the influence of hydraulic nozzles on its atomization and deposition characteristics, droplet size, velocity and deposition distribution of 6 kinds of hydraulic nozzles (standard flat fan XR 110-015, anti-drift flat fan DG 110-015, air-induction flat fan AIXR 110-015, air-induction flat fan AI 110-015, hollow cone TXA 80-015 and air-induction hollow cone AITXA 80-015) were tested. The results showed that droplet sizes of all nozzles decreased with the increase of spray pressure, and the difference of volume median diameter (Dv0.5) between fine (XR 110-015) and medium droplet nozzles (DG 110-015) under different spray pressures was small. In contrast, coarse (AIXR 110-015) and extremely coarse droplet nozzles (AI 110-015 and AITXA 80-015) were more sensitive to spray pressure, and the Dv0.5 of droplet decreased dramatically with the increase of spray pressure. Droplets velocity was mainly determined by the type of nozzles, spray pressure has little effect on droplet velocity, in this case droplet velocity tendency of the same nozzle under different spray pressure was similar. Under the same spray pressure, the average velocity (Vavg) of fine droplet nozzle was greater than its volume median droplet velocity (Vv0.5), while with the increase of the droplet diameter, the Vv0.5 of medium and coarse droplet nozzle exceeded its Vavg. The flow rates of all nozzles were quite similar but lower than its nominal flow rates, and the loss rates of nozzles were ranged from 7.82% to 9.75%. Spray pressure has little effect on droplet distribution uniformity of DG 110-015, XR 110-015 and AIXR 110-015, but a higher pressure was beneficial for the uniformity distribution of AITXA 80-015 and TXA 80-015. This study can provide theoretical guidance and technical reference for the selection of hydraulic nozzles and the optimization of pesticide application parameters.
Meperfluthrin is one of the top-selling sanitary insecticide species in the domestic market, drawing widespread attention due to its environmental safety risk. In this paper, zebrafish was used as an experimental model to assess the cardiac developmental toxicity and oxidative damage caused by acute exposure to meperfluthrin in embryos and larvae. The acute toxicity assessment revealed that meperfluthrin is highly toxic to zebrafish embryos with a 72 h-LC50 of 0.756 μg/mL. After exposure to different doses of meperfluthrin (0, 0.2, 0.4, 0.8 μg/mL) for 72 h, the larvae from 0.4 and 0.8 μg/mL dose-treated groups showed deformities, including spine and tail curvature, pericardium and yolk sac edema, significant reduction of heart rate and hatchability, and incomplete embryonic development (shorter body length, smaller head, and eye area). Moreover, meperfluthrin of 0.2, 0.4, and 0.8 μg/mL induced atrial and ventricular differentiation in larvae, and down-regulated the expression of cardiac function-related genes myl7, myh6, and vmhc. It also increased the content of MDA, as well as decreased the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px), resulting in the accumulation of reactive oxygen species (ROS) in the heart of larvae. The results of this paper indicate that meperfluthrin exposure has significant toxicity to the cardiac development of zebrafish embryos and is associated with oxidative damage.
Some side reactions in the synthetic processes of prothioconazole led to by-products. They negatively affect the yield and quality of prothioconazole. Three different synthetic processes were investigated. Four by-products, including 2-(1-chlorocyclopropyl)-1-(2-chlorophenyl)- 3-(4H-1,2,4-triazol-4-yl)propan-2-ol (7), 6-(2-chlorobenzyl)-6-(1-chlorocyclopropyl)-5,6-dihydro-1,3,4- oxadiazine-4-carbothioamide (8), dimer-prothioconazole (9) and 2-(2-chlorobenzyl)-2-((5-thioxo-4,5- dihydro-1,2,4-triazol-1-yl)methyl)cyclobutanone (10), were synthesized and characterized by 1H-NMR, 13C-NMR, ESI-MS or X-Ray. Among them, the by-product 6-(2-chlorobenzyl)-6-(1-chlorocyclopropyl)-5,6-dihydro-1,3,4-oxadiazine-4-carbothioamide (8) was first discovered during the synthesis of prothioconazole by substituting hydrazine-acetone. The study revealed the mechanism of generation of the four by-products in different processes. The results provided an important guide for the selection and control of the synthetic process of prothioconazole and product quality improvement.
Peanut southern blight is a fungal disease which is caused by the pathgen Sclerotium rolfsii Sacc., and seriously restricts the quality and yield of peanut. In this study, 116 strains of actinomycetes were isolated and purified from rhizosphere soil of Achyranthes bidentata by dilution coating method, and the strains that can control peanut southern blight were screened and identified. Two strains, Soil-1-5 and Soil-3-28, with good and stable antifungal activity, were screened by the plate confrontation test, and their inhibition rates were 92.34% and 80.43%, respectively. Morphological observation, physiological and biochemical tests and 16S rRNA gene sequence analysis identified strains Soil-1-5 and Soil-3-28 as Streptomyces scabiei and Streptomyces luteogriseus, respectively. The inhibition of aseptic fermentation filtrate of antagonistic strains on plant pathogens was measured by mycelium growth rate method. The results showed that after 5 times dilution of aseptic fermentation filtrate of strains Soil-1-5 and Soil-3-28, the inhibit rates of S. rolfsii were 73.67% and 57.11%, respectively, and the two strains had different degrees of inhibition effects on the six plant pathogens including Fusarium graminearum. In addition, the two strains of aseptic fermentation filtrate also had good antagonistic effects on the sclerotinia germination and sclerotinia formation. The results of pot experiment showed that the control effects of strain Soil-1-5 and Soil-3-28 on peanut white silk disease were 51.92% and 31.74%, respectively, and strain Soil-3-28 could promote the growth of peanut. In conclusion, strains Soil-1-5 and Soil-3-28 had better control efficacy on peanut southern blight, and had potential application value.
Insecticide synergists are key components to improve insecticidal efficacy and reduce resistance. In this work, further derivation of the eight-membered oxabridged structure with specific synergistic effect was conducted, fifteen novel N-phenyl-eight-membered oxabridged neonicotinoid derivatives were designed and synthesized, the mortality of the target compounds combined with imidacloprid against Aphis craccivora was tested. The results indicated that most of the target compounds increased the toxicity of imidacloprid against A. craccivora at the concentration of 1 mg/L. The non-substituted compound 4a and 4-CF3-substituted compound 4m exhibited the comparable synergistic effect, the synergism ratio was 3.44 and 3.58, respectively, which could be regarded as candidate compounds for further study.
L-Glufosinate is a new-type herbicide with high herbicidal activity, broad-spectrum and environmental friendliness. It has high cost efficiency and broader application prospects and can be synthesized by chemical synthesis and biocatalytic transformation. On the basis of the investigation of the synthesis methods of L-glufosinate in recent years, the research progress by different synthesis methods of L-glufosinate, such as chiral induction, chiral material, and asymmetric catalysis, were introduced. Finally, the future trends are discussed, which provides valuable information for the follow-up research of the L-glufosinate．
To improve the insecticidal activities of avermectin B2a, the functional carbamate fragment was introduced into the C4" position of avermectin B2a, and 21 novel avermectin B2a C4"-carbamate derivatives were designed, synthesized, and their structures were characterized by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR). The insecticidal activity against Plutella xylostella, Mythimna separata, Spodoptera frugiperda, Ostrinia furnacalis and Helicoverpa armigera was tested. The results showed that the insecticidal activities of most compounds against M. separata, S. frugiperda, O. furnacalis and H. armigera were improved to some degrees. Among them, compound Z5 showed excellent insecticidal activity against M. separata and S. frugiperda, with LC50 values of 1.02 and 2.44 mg/L, respectively. Its insecticidal activity is better than that of the control avermectin B1a, and more than 20 times higher than that of avermectin B2a. The structure-activity relationship analysis showed that more lipophilicity of the compound can help to improve the activity of the target compound. Molecular docking studies showed that with the introduction of the functional carbamate fragment into the C4" position of avermectin B2a, π-π interaction was formed between the benzene ring of the carbamate fragment and the aromatic ring in the receptor protein residue, which was believed to contribute the insecticidal activity of the new compounds.
In order to study the status of pesticide residues in different land use types of soil in Jiaodong area of China,surface soil samples were collected from the main producing areas of apple,peanut and corn on the basis of investigation of the pesticide application on major crops in Jiaodong area.The residues of 43 commonly used pesticides on apples,peanuts,and corn were analyzed by gas chromatography tandem mass spectrometry(GC-MS/MS)and ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).The monitoring results showed that 18 pesticides were detected in soil samples,and the residues ranged from<0.005 to 0.18 mg/kg,with the detection rates of 1.4%-45.7%.The detection rate of imidacloprid,tebuconazole,carbendazim,DDTs,acetochlor and difenoconazole were relatively high.There were significant differences in the types and contents of pesticides in different land use types of soil.In soil samples from apple orchard,16 pesticides were detected and the detection rates of 6 pesticides were relatively high,including tebuconazole,imidacloprid,difenoconazole,carbendazim,chlorpyrifos and DDTs.In soil samples of peanut field,8 pesticides were detected and the detection rates of five pesticides were relatively high,including acetochlor,imidacloprid,DDTs,carbendazim and atrazine.In soil samples of corn field,11 pesticides were detected and the detection rates of five pesticides were relatively high,including imidacloprid,acetochlor,DDTs,carbendazim and difenoconazole.The content of DDTs in one soil sample of corn field(0.18 mg/kg)was higher than the risk screening value,indicating a possible risk of soil pollution in agricultural land.It inferred that the soil environmental monitoring and collaborative monitoring of agricultural products should be strengthened.This study provides basic data for the pesticide pollution situation of different land use types of soil,and also provides reference for the pest control and ecological risk assessment.In the future,it is necessary to continuously enhance the regulatory and monitoring systems,and continuously improve the awareness of pesticide use standards and the environmental quality of soil.
To further enhance the utility of osthole,we designed and synthesized 26 novel osthole derivatives containing the 1,3,4-oxadiazol-2-ylsulfenyl fragment,and measured their insecticidal and acaricidal activities.Meanwhile,through scanning electron microscope(SEM),the effects of compound 6h on the cuticle layer of Tetranychus cinnabarinus Boisduval were observed.The results shown that compound 6h(R=3-OCH3Ph)exhibited the highest acaricidal activity against female adults of T.cinnabarinus with a 72 h LC50 value of 0.466 mg/mL,which was 2.6-fold activity of osthole(LC50 value 1.200 mg/mL);compounds 6u(R=4-CF3Ph)and 6v(R=3-CNPh)displayed the most potent insecticidal activity against the 3rd instar larvae of Plutella xyllostella Linnaeus with 48 h LC50 values of 0.617 and 0.853 mg/mL,respectively;compound 6u showed 2.4-fold insecticidal activity of osthole(LC50 value 1.503 mg/mL).The SEM results showed that the cuticle layer of female adults of T.cinnabarinus was folded and collapsed within 24 h after treatment with compound 6h,and this distinct symptom persisted over time.Overall,this study establishes a framework for the application of osthole derivatives as acaricidal and insecticidal agents.
To investigate the enantioselective behavior of chiral fungicide penthiopyrad in tomato under field and greenhouse conditions,a residue analytical method was developed using ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)for the determination of enantiomers of penthiopyrad in tomatoes based on an optimized QuEChERS approach.The proposed method was used for studying the behavior of residues,dissipation and accumulation of penthiopyrad enantiomers in tomato system under two cultivate patterns.The results indicated that at the range of 0.002-1 mg/L,the linearity of the penthiopyrad enantiomers was good with R2>0.99.At the spiked levels of 0.005,0.1 and 1 mg/kg,the average recoveries of the R-(-)-PEN and S-(+)-PEN in different matrices were 77%-98%and 81%-101%,and the relative standard deviations(RSDs)were 1.6%-5.1%and 1.6%-4.2%,respectively.The limit of quantification(LOQ)was 0.005 mg/kg.The degradation rates of the residues were<30%in tomato samples stored at-20℃for 100 d.The dissipation trend in tomato was fitted with the first-order kinetic equation in both the open field and greenhouse planting modes,and the correlation coefficients(r)were 0.9315-0.9400.The half-lives of R-(-)-PEN and S-(+)-PEN were 5.43 and 5.10 d in the open field,and were 8.09 and7.80 d in the greenhouse modes,respectively.The dissipation of S-(+)-PEN was faster than that of R-(-)-PEN,and the enantiomers of penthiopyrad was accumulated in tomato after repeated spraying.The results of residue distribution also showed that penthiopyrad enantiomers were mainly distributed in the leaves of tomato,and the concentration in tomato leaves,stems and fruits in greenhouse was higher than that in open field.On the 5th days after the last application,the residues of the penthiopyrad were lower than the maximum residue limit(MRL)in China,and the residues of its metabolite(PAM)were lower than the LOQ.The results indicated that the application of penthiopyrad on tomatoes in accordance with the recommended method complies with Good Agricultural Practices in China and meets the basic requirements for food safety.
In order to clarify the temporal and spatial dynamics in the sensitivity of Phytophthora infestans to dimethomorph,mandipropamid,and control efficacies of the commonly used fungicides against potato late blight in one-crop potato planting regions of Northern China,the sensitivity to dimethomorph and mandipropamid in P.infestans strains collected in Hebei Province,Inner Mongolia Autonomous Region and Jilin Province from 2011 to 2019 was measured with the mycelial growth inhibition test.Also,the control efficacies of seven fungicides including dimethomorph and mandipropamid under the recommended dosages to potato late blight were assayed in the fields by spraying stems and leaves with fungicide suspensions in 2018 and 2019.The results showed the resistance frequency and resistance index of 922 P.infestans strains to dimethomorph over the years were 25.71%to 100%and 0.31 to 0.50,respectively.The resistance frequency of 890 P.infestans strains to mandipropamid over the years was 0 to 1.43%and only one resistant strain was found in 2013,and the resistance index was 0.25 for each year.The resistance frequency and resistance index of P.infestans strains in the three provinces to dimethomorph were 57.19%to 66.56%and 0.39 to 0.42,respectively.The resistance frequency of P.infestans strains in the three provinces to mandipropamid was 0 to 0.36%and the resistance index was all 0.25.The results of field efficacy trials showed the control efficacy of dimethomorph 50%WP 300.0 g a.i./hm2(83.3%to 85.6%)were higher than those of mandipropamid 23.4%SC 140.4 g a.i./hm2(76.9%to 78.6%)and fluopimomide 50%WG 75.0 g a.i./hm2(70.0%to 71.4%).The control efficacies of cymoxanil 20%SC 162.0 g a.i./hm2,fluopimomide + dimethomorph 40%SC 240.0 g a.i./hm2,cymoxanil + mandipropamid 43%WG 290.3 g a.i./hm2,and fluopicolide + propamocarb hydrochloride 687.5 g/L SC 773.4 g a.i./hm2 were 79.8%to 86.9%.Thus,dimethomorph singly or in mixtures and mandipropamid in mixtures could be used to control potato late blight in Hebei Province,Inner Mongolia Autonomous Region,and Jilin Province,but it was necessary to monitor the sensitivity dynamics of P.infestans to dimethomorph and mandipropamid,and apply fungicides containing dimethomorph or mandipropamid in mixtures or rotation with the fungicides of different action modes.
2023 年 9 月,中国科学技术信息研究所发布了 2023 年中国科技论文统计结果,《农药学学报》再次入选"百种中国杰出学术期刊"及 "中国精品科技期刊",同时继续入选中国科技核心期刊.
In order to discover compounds with higher antifungal activity and elucidate structure-activity relationship of this class of compounds,a series of butenolide oxime ether derivatives containing 5,5-gem dimethyl moiety were designed and synthesized using 5,5-dimethyl butenolide as the lead structure.Their structures were characterized by 1H NMR,13C NMR and HRMS.The in vitro antifungal activity evaluation revealed that the inhibition rates of compound D13 against Rhizoctonia solani,D8 against Sclerotinia sclerotiorum,D11 and D24 against Botrytis cinerea were 71.2%,69.0%,71.7%and 72.3%at the concentration of 50 mg/L,respectively.As for B.cinerea,the inhibition rates of compounds D5-D30 with 4-pyridine moiety were much higher than those of compounds with substituted benzene at 4-position of butenolide,indicating the pyridine group can improve antifungal activities.These results provide insights into the structure-activity relationship and identify candidates with potent antifungal activity.
Neonicotinoids have been widely used as an important class of insecticides for controlling sap-feeding insects.However,increasing application scope and duration have led to the development of neonicotinoid resistance,decreasing their efficacy.In this study,a series of biphenyl eight-membered oxabridge neonicotinoid analogues were developed based on our previous work.The synergistic activities of target compounds in combination with imidacloprid against the cowpea aphid(Aphis Craccivora)were evaluated,and the results showed that they could effectively enhance the insecticide activities of imidacloprid against A.Craccivora.Notably,compound D3 exhibited obvious synergistic action,causing a 4.04-fold increase in the insecticide activity of imidacloprid against A.Craccivora at a combination concentration of 1 mg/L.This work holds great significance for addressing the resistance issues faced by traditional neonicotinoids.
Thiophanate-methyl,tebuconazole,prochloraz,and difenoconazole have been adopted for many years for the control of hickory canker(Botryosphaeria dothidea).In order to understand the resistance status and guide the prevention and control of hickory canker,the resistance frequencies of B.dothidea to the four fungicides were detected with the discrimination dose assay.EC50 values of the four fungicides to some isolates were also investigated.The fitness differences in mycelial growth rate,number of pycnidia,and pathogenicity between thiophanate-methyl resistant isolates and sensitive ones were determined.The resistance mechanism of thiophanate-methyl resistant isolate was also analyzed.The results showed that most B.dothidea isolates have developed resistance to thiophanate-methyl with a resistance frequency of 84.37%.The average EC50 value of thiophanate-methyl against the four sensitive B.dothidea isolates randomly chosen was 0.263 μg/mL and the relative resistance levels of five resistant isolates were between 49.9-84.8.All the tested isolates were sensitive to tebuconazole,prochloraz,and difenoconazole.The average EC50 values of tebuconazole,prochloraz,and difenoconazole against six B.dothidea isolates chosen at random were 0.148,0.023,and 0.091 μg/mL,respectively.In terms of fitness penalty,no significant difference in pathogenicity was detected between thiophanate-methyl resistant isolates and sensitive ones.However,the mycelial growth rates of the sensitive isolates were significantly faster than that of the resistant isolates,while the number of pycnidia of the sensitive isolates was significantly less than that of the resistant isolates.No mutations of amino acids related to benzimidazole resistance were detected in β-tubulin from isolates resistant to thiophanate-methyl.
Twig blight disease has the characteristics of strong infectivity and rapid onset,which has brought great losses to the production of bayberry fruit.Lignin-based materials are widely used in the field of nanomedicine delivery due to their wide source,low price,and more active functional groups.In order to seek agents with slow-release function for better control of twig blight disease,Di@BLS nanoparticles were prepared by hydrophobically modifying sodium lignosulfonate(LS)and loading difenoconazole(hereafter referred to as Di)as a test agent,which was characterized by 1H nuclear magnetic resonance(1H NMR),fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),dynamic light scattering laser particle sizing(DLS),and the stability of the samples was analyzed by turbiscan stability analyzer(TSI);Di in leaves was extracted by QuEChERs method,and the uptake and translocation of Di@BLS in bayberry were investigated,and finally,diseased branches of bayberry collected for the isolation and identification of pathogenic fungi were carried out.The inhibitory effect of Di@BLS on the bayberry twig blight disease was investigated using the mycelial growth rate method and the pot experiment,respectively.The results showed that the average particle size of Di@BLS was 135.2 nm at a BLS carrier concentration of 1%,a feed/drug ratio of 5:1 and a SDS dosage of 0.2%by mass.The optimized formulation could maintain stability similar to that of Di ME while reducing the amount of surfactant.Both absorption transfer and field experiments confirmed that Di@BLS could delay drug degradation and persist longer in bayberry than Di ME.The results of the mycelial growth rate method showed that the EC50 value of Di@BLS against Lasiodiplodia was 0.643 μg/mL,which is close to that of Di ME.In the pot experiment,at the mass concentration of 200 μg/mL,Di@BLS could reduce the incidence of blight of bayberry by 2.3%compared with Di ME.The results showed that the prepared nanoparticles Di@BLS had a long duration and good antifungal effect in bayberry,which provided a theoretical basis for the prevention and control of twig blight disease of bayberry.
The harmful impacts of succinate dehydrogenase inhibitor(SDHIs)fungicides on aquatic organisms have attracted wide attention in recent years.Inpyrfluxam is a novel SDHI fungicide launched in 2020.However,its toxic effect on aquatic organisms is still unclear.In this study,zebrafish(Danio rerio)embryos were exposed to inpyrfluxam to investigate the lethal and developmental toxicity of inpyrfluxam.The results showed that inpyrfluxam had strong lethality in zebrafish embryos,with 96 h-LC50 of 0.063 mg/L.Inpyrfluxam induced severe teratogenic effects on zebrafish embryos including yolk sac edema,pericardial edema,and spinal curvature at 0.050 mg/L.Obvious inhibition of heartbeat was observed in embryos after exposure to 0.045 mg/L inpyrfluxam.In addition,the hatching rate and body length of embryos were significantly reduced by 0.055 mg/L of inpyrfluxam.In conclusion,inpyrfluxam shows strong lethal and developmental toxicity to zebrafish embryos,and its potential risk to aquatic organisms demands more attention.Our results are of important supplement for aquatic toxicology information of inpyrfluxam,and provide a scientific basis for rational use and environmental safety assessment of inpyrfluxam.
In this study,a green,economical and easy-to-use syringe-assisted dispersive solid phase microextraction method was developed for the rapid detection of the residues of 5 fungicides(azoxystrobin,triadimefon,chlorothalonil,cyprodinil,trifloxystrobin)in two fruit juices(grape juice and apple juice)as well as two tea drink samples(green tea and black tea).A novel extraction material was prepared by coating ionic liquids on β-cyclodextrin/attapulgite,and a series of test experiments for the condition optimization of the method were conducted using liquid chromatography for detection.Results revealed that the optimal condition of the method used 40 mg of extraction material and 600 μL of acetone for elution,and 6 dispersion cycles and 7 elution cycles were performed.The detection limits(LOD)for the 5 compounds were 0.03-0.38 μg/L,and the limits of quantification(LOQ)were 0.09-1.15μg/L,with the enrichment factors ranged from 121 to 201.The linear detection range of the five fungicides was 5 to 500 μg/L,with the coefficient of determination(R2)ranging from 0.9982 to 0.9999.The fortified recoveries were 91%-102%.It showed that the method had good precision and accuracy.The testing results for real samples indicated that the syringe-assisted dispersive solid phase microextraction technology can be used for the extraction of residual fungicides in beverages.
