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1.
Food Chem ; 367: 130653, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343809

RESUMO

A uniform spherical structure covalent organic framework (TAPA-BPDA-COF) was prepared by a facile method at room temperature with tris(4-aminophenyl)amine (TAPA) and 4,4'-biphenyldicarboxaldehyde (BPDA) as building blocks. Based on the solid phase extraction with the TAPA-BPDA-COF as the sorbent and high performance liquid chromatography-diode array detection, a sensitive analytical method was established for the determination of four neonicotinoid insecticides from water and honey samples. Under the optimum conditions, good linear response for the quantification of the analytes was achieved in the range of 0.3-50.0 ng mL-1 for water samples and in the range of 8.0-500.0 ng g-1 for honey samples. The method recoveries fell in the range of 80.0-121.9% with RSDs less than 7.6%. The limits of detection at the signal to noise ratio of 3 were measured to be in the range of 0.08-0.12 ng mL-1 for water samples and 2.6-3.3 ng g-1 for honey samples, depending on compounds.


Assuntos
Inseticidas , Estruturas Metalorgânicas , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Neonicotinoides , Extração em Fase Sólida
2.
Food Chem ; 367: 130740, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34375891

RESUMO

Traditional sample preparation methods for insecticide analysis are laborious and fatal to living organisms. In the work, an in vivo sampling rate calibrated-solid phase microextraction-gas chromatography-mass spectrometry method was established and successfully used for in vivo sampling and quantitative determination of three insecticides (hexachlorobenzene, fipronil and chlorfenapyr) by direct exposing micron-sized fiber in living garlic. Absorption, enrichment, migration and elimination behavior of insecticides in garlic were investigated. Bioaccumulative effects with obvious tissue differences were observed to all three insecticides, especially for chlorfenapyr. Bioconcentration factors (BCFs) ranging from 0.0342 to 1.0887 were obtained, and the closer to roots, the higher BCFs. The half-life of insecticides in garlic ranged from 0.43 to 0.96 d. In the first 24 h, 55.0% - 80.3% insecticides residues in garlic were eliminated with first-order elimination kinetics. The research provides in vivo insights into the environmental fates of insecticides in complex living system with minimized organism damage.


Assuntos
Alho , Inseticidas , Resíduos de Praguicidas , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas/análise , Resíduos de Praguicidas/análise , Microextração em Fase Sólida
3.
Parasitol Int ; 86: 102483, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34678492

RESUMO

This study examines the biological efficacy of four mosquito mat vaporizers each containing different active ingredients: prallethrin with PBO, dimefluthrin, prallethrin, and d-allethrin. The glass chamber assay was used to evaluate their efficacy on Aedes albopictus (Skuse) (Diptera: Culicidae) from nine districts in Selangor, Malaysia. Aedes albopictus exhibited different knockdown rates, with 50% knockdown times, KT50, varying from 1.19 to 2.00 min, 1.22 to 2.20 min, 1.39 to 5.85 min, and 1.39 to 1.92 min for prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. In general, all populations of Ae. albopictus were completely knocked down after exposure to all active ingredients except Hulu Selangor population, which showed 96.00% knockdown against d-allethrin. On the contrary, mortality rates were observed from 84.00-100.00%, 84.00-100.00%, 90.67-100.00% and 90.67-100.00% in populations tested with prallethrin with PBO, dimefluthrin, prallethrin and d-allethrin, respectively. Moreover, significant correlations between mortality rates of prallethrin with PBO vs dimefluthrin (r = 0.836, P = 0.003), prallethrin with PBO vs prallethrin (r = 0.760, P = 0.011), and prallethrin vs d-allethrin (r = 0.694, P = 0.026) were also observed, suggesting cross-resistance among pyrethroids. d-allethrin was found to be high in insecticidal activity, followed by prallethrin, prallethrin with PBO, and dimefluthrin. In consistent with mortality due to insecticide exposure, elevated levels of enzyme activities were also demonstrated in Sabak Bernam, Hulu Selangor, Gombak, Petaling, Hulu Langat and Klang populations.


Assuntos
Aedes , Inseticidas , Controle de Mosquitos , Nebulizadores e Vaporizadores , Aedes/genética , Animais , Inativação Metabólica , Malásia , Fenótipo
4.
Sci Total Environ ; 803: 150026, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34500277

RESUMO

Pesticides are extensively used to control pests, diseases, and weeds in order to increase agricultural production. Usage of indiscriminate doses and persistent pesticides has not only caused resistance issues in insect pests but has also had deleterious effects on non-target organisms (beneficial insects, fish, and wildlife) and caused environmental contamination (soil, water, and air) through leaching, overflow, and insecticide spray drift. Exposure from eating food and drinking water contaminated to pesticide residues is also affecting human health. This study was conducted to obtain information to reduce pesticide resistance and environmental pollution. A cotton dusky bug (Oxycarenus hyalinipennis) population was collected from a farmer's field and exposed to fipronil for 18 generations. In comparison to an unselected strain (XYZ-FS) and a field population (Field-Popn), the fipronil-selected strain of O. hyalinipennis (XYZ-FR) developed a 2631.50-fold level of resistance and a 202.42-fold resistance level respectively. Significantly higher fecundity was observed in the XYZ-FS (24.93) compared to that of Hybrid2 (XYZ-FR ♀ XYZ-FS ♂) (17.60), Hybrid1 (XYZ-FR ♂ × XYZ-FS ♀) (17.13), and XYZ-FR (12.6). The intrinsic rate of natural increase, relative fitness and biotic potential were highest in XYZ-FS, followed by Hybrid2, Hybrid1, and XYZ-FR. The XYZ-FR strain of O. hyalinipennis had very low cross-resistance to profenofos (1.15-2.83-fold), and emamectin benzoate (1.09-2.86-fold) and moderate resistance to bifenthrin (5.49-24.54-fold) when selection progressed from G4 to G19. The proper use of this pesticide, along with rotation and a high-dose strategy may helpful to reduce the risk of resistance development and also its negative impacts on the environment and humans.


Assuntos
Heterópteros , Inseticidas , Animais , Humanos , Resistência a Inseticidas , Inseticidas/toxicidade , Pirazóis , Medição de Risco
5.
Chemosphere ; 286(Pt 1): 131642, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34351280

RESUMO

Neonicotinoids are replacement insecticides increasingly used for organophosphates, methylcarbamates, and pyrethroids. Experimental evidence suggests neonicotinoids may affect glucose metabolism and insulin secretion through pancreatic ß cell dysfunction, oxidative stress, and inflammation. However, no epidemiologic study has investigated neonicotinoids as potential diabetogens. We examined associations between neonicotinoids with insulin and glucose homeostasis parameters among 1381 non-diabetic adults in the National Health and Nutrition Examination Survey (2015-2016). Urinary concentrations of acetamiprid, clothianidin, imidacloprid, N-desmethyl-acetamiprid, and 5-hydroxy-imidacloprid were quantified. Fasting plasma glucose, insulin, and hemoglobin A1c (HbA1c) were assessed. Insulin resistance was defined as a homeostatic model assessment of insulin resistance ≥2.5. We used weighted linear and logistic regression to estimate associations between detectable neonicotinoids with insulin and glucose homeostasis parameters compared to non-detectable neonicotinoid concentrations. Weighted detection frequencies for imidacloprid, 5-hydroxy-imidacloprid, and N-desmethyl-acetamiprid were 4.4 %, 21.5 %, and 32.8 %, respectively. Detectable imidacloprid (ß = -4.7 µIU/mL, 95 % confidence interval [CI] -8.5, -0.8) and 5-hydroxy-imidacloprid (ß = -2.4 µIU/mL, 95 % CI -4.6, -0.2) were associated with lower fasting plasma insulin levels. Individuals with detectable 5-hydroxy-imidacloprid had lower odds of insulin resistance (odds ratio [OR] = 0.3, 95 % CI 0.2, 0.7). We observed evidence of sexually dimorphic associations between N-desmethyl-acetamiprid with glucose (pint = 0.079) and 5-hydroxy-imidacloprid with HbA1c (pint = 0.038), with patterns suggesting positive associations in males and negative associations in females. Associations between 5-hydroxy-imidacloprid and insulin were modified by body mass index (BMI) (pint = 0.013). We additionally observed age modified associations between 5-hydyroxy-imidacloprid and glucose (pint = 0.048). Results suggest neonicotinoids may be associated with insulin and glucose homeostasis indices and call for prospective studies to examine the metabolic impact of these replacement insecticides in humans.


Assuntos
Inseticidas , Insulina , Adulto , Feminino , Glucose , Homeostase , Humanos , Inseticidas/toxicidade , Masculino , Neonicotinoides , Nitrocompostos , Inquéritos Nutricionais , Estudos Prospectivos
6.
Chemosphere ; 286(Pt 3): 131926, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34435577

RESUMO

The redclaw crayfish, Cherax quadricarinatus, was introduced to Martinique Island for aquaculture purposes at the beginning of the 21st century, in an attempt to revitalize the freshwater crustacean aquaculture sector. Mainly due to its high economical value, it was intentionally released in the wild and was caught and sold by fishermen. Martinican rivers are polluted by chlordecone, considered as one of the worst Persistant Organic Pollutants (POP). Despite its dangerousness, it was used until 1993 in the French West Indies against a banana pest and was always found in the ecosystems. This study aimed to investigate the level of contamination in the muscle of crayfish caught in the wild, as well as the potential of bioconcentration and depuration in the C. quadricarinatus muscle. This study could allow us to quantify the risk for consumers but also, to evaluate a depuration process to reduce the risk related to its consumption. Using both in-vitro and in-situ experiments, results highlighted the importance of the chlordecone concentration in the water and the time of exposure to the pollutant. The bioconcentration seems to be very quick and continuous in crayfish muscle, as chlordecone can be detectable as early as 6 h of exposure, whatever the concentration tested. Finally, it appears that, even after 20 days of depuration in chlordecone-free water, chlordecone concentrations remained higher to the residual maximum limit (i.e. 20 ng/g wet weight), concluding that the decontamination of the muscle seems not very efficient, and the risk for the Martinican people could be serious.


Assuntos
Clordecona , Inseticidas , Animais , Astacoidea , Bioacumulação , Clordecona/análise , Ecossistema , Humanos , Inseticidas/análise , Martinica
7.
J Sci Food Agric ; 102(1): 341-349, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34111305

RESUMO

BACKGROUND: Neonicotinoids are widely used insecticides, and tea is a popular non-alcoholic beverage in Taiwan. However, the levels of neonicotinoids in Taiwanese tea leaves remain unclear. Therefore, this study aims to understand the characteristics of neonicotinoid and metabolite residues in Taiwanese tea leaves. METHODS: In this study, 12 tea leaf samples were collected in Taiwan and extracted by solid-phase extraction before analysis by liquid chromatography-tandem mass spectrometry. In addition, the levels of neonicotinoids were compared with the maximum residue level standards from other countries. RESULTS: In Taiwanese tea leaves, five neonicotinoids and seven metabolites were detected. Different tea species influenced the levels of neonicotinoids and their metabolites in the present study. Moreover, the levels of neonicotinoids and their metabolites in partially fermented leaves were higher than in completely fermented leaves. In Jin-Xuan tea, the levels of neonicotinoids and their metabolites in most winter-harvested teas were lower than in summer-harvested teas. CONCLUSION: The residue levels of neonicotinoids and their metabolites were detectable in Taiwanese tea leaves. Moreover, different tea species, manufacturing processes, and harvest seasons might influence the levels of these pesticides. Therefore, the government should monitor the use of neonicotinoids. © 2021 Society of Chemical Industry.


Assuntos
Camellia sinensis/química , Inseticidas/análise , Neonicotinoides/análise , Resíduos de Praguicidas/análise , Cromatografia Líquida , Contaminação de Alimentos/análise , Folhas de Planta/química , Extração em Fase Sólida , Taiwan , Espectrometria de Massas em Tandem , Chá/química
8.
Biol Trace Elem Res ; 200(1): 228-237, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33566284

RESUMO

Organophosphate compounds are the most widely employed insecticides in countries with high agriculture activity. On average, organophosphates cause 3 million people to poison and 200 000 deaths per year due to food chain or occupational, accidental, or suicidal exposure. Our study aimed to research selenium's protective role against the toxic action of CPF, one of the most commonly used organophosphates, with an experimental model formed with rats. A total of 56 male SD rats were distributed into seven groups as follows: control (tap water), sham (corn oil), group I (5.4 mg/kg CPF), group II (13.5 mg/kg CPF), group III (3 mg/kg Se), group IV (5.4 mg/kg CPF+Se), and group V (13.5 mg/kg CPF+Se). Following 6 weeks of oral exposure, there were significant changes in AChE activity, biochemical and hematological parameters, and trace element levels in CPF-treated rats. In the high-dose CPF group, RBC values, Hb, and Hct decreased, and values of WBC, AST, ALT, ALP increased (p < 0.001) significantly compared to control, sham, and Se groups. While there was no significant change in zinc level, the copper and selenium levels were significantly higher in group IV than in control (p < 0.001) and sham (p < 0.05, p < 0.01, respectively) groups. Moreover, max. O.R.L. was found statistically more elevated in the high-dose CPF group compared to control, sham, and Se groups (p < 0.05, p < 0.05, and p < 0.01, respectively). All results indicated that Se is an antioxidant that reduces the toxic effects caused by CPF. Employing combinations of chlorpyrifos and selenium appeared greatly in restoring the harmful effects of CPF exposure.


Assuntos
Clorpirifos , Inseticidas , Selênio , Oligoelementos , Animais , Clorpirifos/toxicidade , Inseticidas/toxicidade , Masculino , Ratos , Ratos Sprague-Dawley , Selênio/farmacologia
9.
Sci Total Environ ; 804: 150254, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798758

RESUMO

Although the toxicity of neonicotinoid insecticides has been demonstrated in several studies, the information on metabolism, behavior, and health risk remains limited and has raised concerns about its potential toxicity. Thus, in this study we assessed the effects of nitenpyram using different sublethal concentrations (one-third and one-tenth of the acute LC50 values) on various developmental and metabolic parameters from gene expression regulation in Drosophila melanogaster (model system used worldwide in ecotoxicological studies). As a result, nitenpyram sublethal concentrations prolonged the developmental time for both pupation and eclosion. Additionally, nitenpyram sublethal concentrations significantly decreased the lifespan, pupation rate, eclosion rate, and production of eggs of D. melanogaster. Moreover, the mRNA expression of genes relevant for development and metabolism was significantly elevated after exposure. Mixed function oxidase enzymes (Cyp12d1), (Cyp9f2), and (Cyp4ae1), hemocyte proliferation (RyR), and immune response (IM4) genes were upregulated, whereas lifespan (Atg7), male mating behavior (Ple), female fertility (Ddc), and lipid metabolism (Sxe2) genes were downregulated. These findings support a solid basis for further research to determine the hazardous effects of nitenpyram on health and the environment.


Assuntos
Proteínas de Drosophila , Drosophilidae , Inseticidas , Praguicidas , Animais , Proteína 7 Relacionada à Autofagia , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophilidae/metabolismo , Feminino , Inseticidas/toxicidade , Masculino , Neonicotinoides , Reprodução , Transcriptoma
10.
Environ Pollut ; 291: 118221, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34740294

RESUMO

Sulfur, an essential macronutrient, plays important roles in plant development and stress mitigation. Sulfur deficiency, a common problem in agricultural soils, may disturb plant stress resistance and xenobiotic detoxification. In the present study, the function and mechanism of limited sulfur nutrition on the residues and phtotoxicity of imidacloprid were investigated in lettuce plants. Sulfur deficiency significantly increased imidacloprid accumulation in lettuce tissues, exacerbated imidacloprid biological toxicity by enhancing the accumulation of toxic metabolites, like imidacloprid-olefin. Simultaneously, imidacloprid-induced detoxification enzymes including cytochromes P450, glutathione S-transferases (GSTs) and glycosyltransferases were inhibited under limited sulfur supply. On the other hand, sulfur deficiency further enhanced the generation of reactive oxygen species and exacerbated lipid peroxidation in lettuce tissues. Sulfur deficiency mainly reduced the abundance of thiol groups, which are essential redox modulators as well as xenobiotic conjugators, and significantly inhibited GSTs expression. These results clearly suggested that sulfur deficiency inhibited the synthesis of sulfur-containing compounds, leading to increased accumulation of pesticide residues and toxic metabolites as well as reduced detoxification capacity, consequently leading to oxidative damage to plants. Therefore, moderate sulfur supply in regions where neonicotinoid insecticides are intensively and indiscriminately used may be an efficient strategy to reduce pesticide residues and the potential risk to ecosystem.


Assuntos
Inseticidas , Plântula , Ecossistema , Inseticidas/toxicidade , Alface , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Compostos de Sulfidrila , Enxofre
11.
Environ Pollut ; 291: 118225, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34740295

RESUMO

Several transformation products (or metabolites) of neonicotinoid insecticides (NNIs) have been detected in drinking water, such as desnitro-imidacloprid and imidacloprid-urea. However, data on the occurrences of the metabolites of NNIs (mNNIs) in drinking water are mainly limited to the imidacloprid metabolites. To identify whether the potential metabolites of other widely used NNIs (such as acetamiprid, clothianidin, and thiamethoxam) occur in drinking water and to characterize their distribution profiles, twelve selected (mainly urea and desnitro/decyano) metabolites of NNIs were measured in drinking water samples (n = 884, including n = 789 for tap water, and n = 95 for shallow groundwater) that were collected from 32 provinces in mainland China and Hong Kong. Nearly 90% of the drinking water samples contained the detected mNNI residues. Among the selected mNNIs, thiamethoxam-urea (THM-urea: 76%) and decyano-acetamiprid (decyano-ACE: 73%) were frequently detected (median: 0.94 and 0.25 ng/L, respectively), which were followed by clothianidin-urea (CLO-urea: 45%), desnitro-thiamethoxam (DN-THM: 38%), and other mNNIs (detected in less than 30% of the water samples). Surface-water-sourced tap water had an approximately 8-10 times higher median cumulative concentration (ng/L) of the selected mNNIs (ΣmNNIs: 3.88) than the deep groundwater-sourced tap water (0.53) and groundwater that was directly used as drinking water (0.38). Higher ratios of THM-urea accounted for ΣTHM in north and northwest China than in south China could be partly explained by the decreasing soil pH values from north to south in China. The higher ratios of decyano-ACE accounted for ΣACE in south China than in north and northwest China could be attributable to the lower soil pH levels, higher temperatures, and greater light intensities in south China. The THM-urea, decyano-ACE, and ΣmNNIs levels in cities were found to be significantly higher than those in nonurban areas. The THM-urea levels in seven drinking water samples from Guangxi and Henan Provinces exceeded the guideline limit (100 ng/L) of the European Union. This is the first study to identify THM-urea, decyano-ACE, CLO-urea, and DN-THM in drinking water. To better assess the mass loadings of NNIs in drinking water, mNNIs should be considered in further studies.


Assuntos
Água Potável , Inseticidas , China , Água Potável/análise , Inseticidas/análise , Neonicotinoides/análise , Nitrocompostos
12.
Exp Appl Acarol ; 85(2-4): 191-204, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34739615

RESUMO

The overuse of insecticides to control vector insects such as Diaphorina citri Kuwayama in citrus groves has altered the population dynamics of pest mites. Among phytophagous mites, population outbreaks of citrus leprosis mite, Brevipalpus yothersi Baker, have been increasingly intense and frequent in Brazilian citrus groves. Despite the great importance of the B. yothersi mite for citrus production, the lethal and sublethal effects of insecticides on this mite have not yet been studied. Therefore, in this study, the effects of insecticides commonly used for D. citri control on B. yothersi mortality, reproduction, and instantaneous growth rate were assessed. For this, two experiments were carried out, one under controlled conditions and another in a greenhouse. The insecticides tested were beta-cyfluthrin, bifenthrin, buprofezin, chlorpyrifos, dimethoate, pyriproxyfen, and thiamethoxam at 0 (control), 0.0625, 0.125, 0.25, 0.5, 1, and twofold the recommended insecticide concentration for D. citri control. The pyriproxyfen insecticide provided high mortality of B. yothersi even at low concentrations. Furthermore, this insecticide negatively interfered with the reproduction of this mite. Beta-cyfluthrin, bifenthrin, buprofezin, chlorpyrifos, dimethoate, and thiamethoxam, in the tested concentrations, showed low impact on citrus leprosis mite. Regarding the reproduction of the mite, no significant increase in fecundity was observed on B. yothersi females exposed to insecticide residues, regardless of the concentration tested. Therefore, the application of these insecticides in the management of pest insects is unlikely to promote an increase in the citrus leprosis mite population.


Assuntos
Citrus , Inseticidas , Ácaros , Animais , Fertilidade , Reprodução
13.
Trials ; 22(1): 825, 2021 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-34802455

RESUMO

BACKGROUND: While there is strong evidence that bite protection methods such as permethrin-treated clothing and topical insect repellents are protective against insect bites, there are few studies assessing the impact on malaria infection. This study will estimate the protective efficacy of treated uniforms and DEET insect repellent on the incidence of malaria infection among military personnel in an operational setting. Permethrin-treated uniforms used with DEET lotion will be compared to etofenprox-treated uniforms with DEET lotion. The effect of DEET lotion will be estimated by comparing permethrin-treated uniforms with DEET or placebo lotion. METHOD: A cluster randomised double-blind placebo-controlled trial is planned to evaluate the effectiveness of the interventions on preventing malaria infections in soldiers on active duty at Mgambo National Service Camp in Tanga, Tanzania. The arms are (1) permethrin-treated uniform with 30% DEET liposome formula; (2) permethrin-treated uniform with placebo lotion; (3) candidate insect repellent system, i.e. etofenprox-treated uniform with 30% DEET liposome formula; and (4) placebo, i.e. untreated uniforms with placebo lotion. The primary outcome is the incidence of Plasmodium falciparum malaria infection detected by polymerase chain reaction (PCR) by active case detection using surveys every 2 weeks for 12 months. Rapid diagnostic tests will be used for the diagnosis of participants with symptoms. The unit of randomisation will be combania: companies formed by recruits aged 18 to 25 years; combania do activities together and sleep in the same dormitory. Unequal randomisation will be used to optimise statistical power for the primary comparison between permethrin-treated uniforms with DEET and etofenprox-treated uniforms with DEET. DISCUSSION: This trial will provide the estimate of the effects of permethrin with DEET compared to those of the new fabric treatment etofenprox with DEET and any additional effect of using DEET. The results will inform strategies to protect military personnel and civilians who have more outdoor or occupational malaria exposure than the general public. TRIAL REGISTRATION: ClinicalTrials.gov NCT02938975 .


Assuntos
Repelentes de Insetos , Inseticidas , Malária , Militares , Vestuário , DEET/efeitos adversos , Humanos , Incidência , Repelentes de Insetos/efeitos adversos , Malária/diagnóstico , Malária/epidemiologia , Malária/prevenção & controle , Permetrina/efeitos adversos , Piretrinas , Ensaios Clínicos Controlados Aleatórios como Assunto , Tanzânia/epidemiologia
14.
Pestic Biochem Physiol ; 179: 104965, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802515

RESUMO

The fall armyworm (FAW), Spodoptera frugiperda, is a global pest of multiple economically important row crops and the development of resistance to commercially available insecticidal classes has inhibited FAW control. Thus, there is a need to identify chemical scaffolds that can provide inspiration for the development of novel insecticides for FAW management. This study aimed to assess the sensitivity of central neurons and susceptibility of FAW to chloride channel modulators to establish a platform for repurposing existing insecticides or designing new chemicals capable of controlling FAW. Potency of select chloride channel modulators were initially studied against FAW central neuron firing rate and rank order of potency was determined to be fipronil > lindane > Z-stilbene > DIDS > GABA > E-stilbene. Toxicity bioassays identified fipronil and lindane as the two most toxic modulators studied with topical LD50's of 41 and 75 ng/mg of caterpillar, respectively. Interestingly, Z-stilbene was toxic at 300 ng/mg of caterpillar, but no toxicity was observed with DIDS or E-stilbene. The significant shift in potency between stilbene isomers indicates structure-activity relationships between stilbene chemistry and the binding site in FAW may exist. The data presented in this study defines the potency of select chloride channel modulators to FAW neural activity and survivorship to establish a platform for development of novel chemical agents to control FAW populations. Although stilbenes may hold promise for insecticide development, the low toxicity of the scaffolds tested in this study dampen enthusiasm for their development into FAW specific insecticides.


Assuntos
Inseticidas , Estilbenos , Animais , Resistência a Inseticidas , Inseticidas/toxicidade , Spodoptera , Estilbenos/toxicidade , Zea mays
15.
Pestic Biochem Physiol ; 179: 104967, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802517

RESUMO

Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) is a predominant endoparasitoid of lepidopteran pests in mulberry fields. Extensive application of insecticides puts natural enemies under threat. UDP-glycosyltransferases (UGTs), as important detoxification enzymes, potentially contribute to the detoxification of pesticides in insects. To investigate the roles of UGTs in the process of tolerance towards commonly used insecticides in M. pulchricornis, ten UGT genes were identified from the transcriptome database of M. pulchricornis. Seven UGT genes contained full-length ORFs and shared 47.12-78.28% identity with other homologous hymenopteran insects. qRT-PCR validation revealed that UGT genes can be induced by treatment of sublethal doses of phoxim, cypermethrin and chlorfenapyr, respectively, and these upregulations were depending on the time post insecticide treatments. To further explore the functions of UGT genes, three MpulUGT genes were singly knocked down, which resulted in the decline of UGT expression and significantly increased mortality of parasitoids under sublethal doses of insecticides exposure. This study revealed that UGTs in M. pulchricornis contributed to the tolerance towards insecticides and provided basic insight into the insecticide detoxification mechanism in parasitoid wasps.


Assuntos
Inseticidas , Vespas , Animais , Glicosiltransferases/genética , Inseticidas/toxicidade , Difosfato de Uridina , Vespas/genética
16.
Pestic Biochem Physiol ; 179: 104969, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802519

RESUMO

Carboxylesterases (CarEs) usually play critical roles in the detoxification of toxic chemicals and therefore may be involved in insecticide resistance in agricultural pests. Previous work has shown that CarE 001C from Helicoverpa armigera was able to metabolize the isomers of cypermethrin and fenvalerate. In this study, seven mutants of CarE 001C with single amino acid substitution were produced and expressed in the Escherichia coli. Enzyme kinetic analysis indicated that all seven mutations dramatically reduced enzymatic activities toward the generic substrate α-naphthyl acetate, but in vitro metabolism assay showed that two of the mutations, H423I and R322L, significantly improved hydrolase activities toward fenvalerate, with their recorded specific activities being 3.5 and 5.1 nM·s-1·mg -1 proteins, respectively. Further, thermostability assay showed that the stability of one mutant enzyme was enhanced. This study will help us better understand the potential of CarEs in insecticide detoxification and resistance in H. armigera.


Assuntos
Inseticidas , Mariposas , Piretrinas , Animais , Carboxilesterase/genética , Carboxilesterase/metabolismo , Hidrolases de Éster Carboxílico/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Cinética , Mariposas/genética , Mariposas/metabolismo , Mutação , Nitrilas
17.
Pestic Biochem Physiol ; 179: 104973, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802523

RESUMO

The fall armyworm (FAW) Spodoptera frugiperda (Lepidoptera: Noctuidae) is a severe agricultural pest, which has invaded into China in 2019 and caused heavy damage to maize. The γ-aminobutyric acid receptor (GABAR)-targeted insecticides including broflanilide, fluralaner and fipronil exhibit high toxicity towards lepidopteran pests. However, whether they could be used for control of FAW and their possible mode of action in FAW remain unclear. In this study, broflanilide, fluralaner and fipronil exhibited high oral toxicity in FAW larvae with median lethal dose (LD50) values of 0.677, 0.711, and 23.577 mg kg-1 (active ingredient/ artificial food), respectively. In the electrophysiological assay, fluralaner and fipronil could strongly inhibit GABA-induced currents of homomeric FAW resistance to dieldrin 1 (RDL1) receptor with median inhibitory concentration (IC50) values of 5.018 nM (95% confidence interval (CI) 2.864-8.789) and 8.595 nM (95% CI 5.105-14.47), respectively, whereas broflanilide could not. In addition, the cytochrome P450 (P450), glutathione-S-transferase (GST) and carboxylesterase (CarE) activities were positively response to broflanilide, P450 and GST to fluralaner, and GST and CarE to fipronil, respectively, compared with those of control. In conclusion, we firstly reported a notable insecticidal activity of three representative GABAR-targeted insecticides to FAW in vivo, and in vitro using electrophysiological assay. The GST is the primary detoxification enzyme for three tested insecticides. Our results would guide the rotational use of GABAR-targeted insecticides in field.


Assuntos
Inseticidas , Animais , Inseticidas/toxicidade , Larva , Receptores de GABA , Spodoptera , Zea mays
18.
Pestic Biochem Physiol ; 179: 104975, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802525

RESUMO

Pesticides are one of the main causes of colony losses globally, posing a huge threat to the beekeeping industry. The fungicide carbendazim is commonly used on many crops worldwide, but the effects of fungicides on honey bees have received less attention than those of insecticides. Previous studies have shown that sublethal doses of carbendazim hinder growth and development and may destabilize and impede the development of honey bee colonies. The metabolome closely reflects brain activity at the functional level, allowing the effects of compounds such as fungicides to be investigated. Here, we established a model of carbendazim-treated honey bees, Apis mellifera, and used metabolomic approaches to better understand the effect of carbendazim on bee metabolic profiles. The results showed that 112 metabolites were significantly affected in carbendazim-treated bees compared to the control. Metabolites associated with energy and amino acid metabolism showed high abundance and were enriched for a wide range of pathways. In addition, the down-regulation of Aflatoxin B1exo-8,9-epoxide-GSH and glycerol diphosphate showed that carbenazim may affect the detoxification and immune system of honey bees. These results provide new insights into the interaction between fungicides and honey bees.


Assuntos
Inseticidas , Espectrometria de Massas em Tandem , Animais , Abelhas , Benzimidazóis , Carbamatos/toxicidade , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Inseticidas/toxicidade
19.
Pestic Biochem Physiol ; 179: 104977, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802527

RESUMO

Chlorpyrifos (0,0-diethyl 0-(3,5,6-trichloro-2-pyridinyl)-phosphorothioate; (CPF)) is a widely used lipophilic organophosphorus insecticide that primarily manifests into central and peripheral nervous system toxicity. However, it is poorly investigated as a developmental neurotoxicant and thus remains less explored for pharmacological interventions as well. Berberine (BBR) is a benzylisoquinoline alkaloid, primarily found in the plants of Berberidaceae family, and is used for the synthesis of several bioactive derivatives. The goal of this study was to evaluate the CPF-induced neuronal damage through lactational route and analyze the neuroprotective efficacy of berberine (BBR), a potent antioxidant compound in the F1 generation. The environmentally relevant dose of CPF (3 mg/kg b.wt.) was administered via gavage to pregnant dams from postnatal day 1 to day 20 (PND 1-20). BBR (10 mg/kg b.wt.) was administered concurrently with CPF for the same duration as a co-treatment. Levels of reactive oxygen species, lipid peroxidation, membrane bound ATPases (Na+K+ATPase, Ca2+ATPase, and Mg2+ATPase), DNA damage, histomorphological alterations, cellular apoptosis were increased, and activities of glutathione reductase, endogenous antioxidant enzymes (SOD, CAT, GST, and GR) were decreased in cerebellum and cerebrum regions of CPF exposed pups. CPF triggered neuronal apoptosis by upregulating Bax and caspase-3 and downregulating Bcl-2. Co-treatment of BBR significantly attenuated these effects of CPF signifying oxidative stress mediated chlorpyrifos induced neuronal apoptosis. Berberine treatment ameliorated the CPF-induced downregulation of Bcl-2, Bax translocation, and up-regulation of caspase-3 in F1 pups. Therefore, BBR owing to its multiple pharmacological properties can be further explored for its therapeutic potential as an alternative neuroprotective agent against lactational exposure of chlorpyrifos-induced developmental neurotoxicity.


Assuntos
Berberina , Clorpirifos , Inseticidas , Animais , Berberina/toxicidade , Clorpirifos/toxicidade , Inseticidas/toxicidade , Compostos Organofosforados , Estresse Oxidativo , Ratos , Ratos Wistar
20.
Pestic Biochem Physiol ; 179: 104941, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34802531

RESUMO

Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is an insect popularly known as the red flour beetle, it is widely distributed worldwide and can cause serious damage to stored grains. Chemical control is the most used method for managing this pest, however, some substances are toxic to mammals and the environment. Therefore, the development of new effective and safe insecticides is necessary. Essential oils (EOs) can be considered as a potential alternative in the development of pesticides due to their physicochemical properties and varied effects against insects. In the current study, was determined the fumigant toxicity and biochemical effects of selected essential oils against T. castaneum. The 23 selected EOs were characterized by GC-MS and their fumigant lethal concentrations were determined. An exploratory Cluster analysis was performed to find a relationship between fumigant toxicity and chemical composition. Finally, the inhibition of the catalytic activity of acetylcholinesterase (AChE), glutathione S-transferase (GST) and catalase (CAT) was evaluated using protein homogenates obtained from T. castaneum. The results indicated that EOs with the highest fumigant potential were those with greater diversity in their composition, while the least active EOs presented mainly monoterpenes. The most active EOs were those obtained from Foeniculum vulgare and Zanthoxylum monophyllum with LC50 values of 16.23 and 18.54 µL/L air respectively. Regarding the inhibition of the enzymatic activity of the 23 EOs evaluated at 500 µL/L, only two caused an inhibition greater that 50% on AChE, which corresponded to EOs from Piper nigrum and Rosmarinus officinalis. Likewise, EOs from C. sinensis, Piper aduncum and Zanthoxylum monophyllum were the only ones able to inhibiting GST activity by more than 50%. Respecting CAT inhibition, 7 EOs caused and inhibition greater than 50%, highlighting those from Lavandula angustifolia, C. sempervirens and Eucalyptus sp. These results show that the EOs evaluated in this study seems to be a promising bio-controller of T. castaneum since have high fumigant toxicity and exert different mechanisms of action.


Assuntos
Besouros , Inseticidas , Óleos Voláteis , Tribolium , Acetilcolinesterase , Animais , Inseticidas/toxicidade , Óleos Voláteis/toxicidade
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