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1.
Int J Mol Sci ; 22(24)2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34948092

RESUMO

Neonicotinoids (NEO) represent the main class of insecticides currently in use, with thiamethoxam (THX) and clothianidin (CLO) primarily applied agriculturally. With few comprehensive studies having been performed with non-target amphibians, the aim was to investigate potential biomarker responses along an adverse outcome pathway of NEO exposure, whereby data were collected on multiple biological hierarchies. Juvenile African clawed frogs, Xenopus laevis, were exposed to commercial formulations of THX and CLO at high (100 ppm) and low (20 ppm) concentrations of the active ingredient. Mortality, growth, development, liver metabolic enzyme activity, and gene expression endpoints were quantified. Tadpoles (n > 1000) from NF 47 through tail resorption stage (NF 66) were exposed to NEO or to NEO-free media treatments. Liver cell reductase activity and cytotoxicity were quantified by flow cytometry. Compared to control reference gene expressions, levels of expression for NEO receptor subunits, cell structure, function, and decontamination processes were measured by RT-qPCR by using liver and brain. Mortality in THX high was 21.5% compared to the control (9.1%); the metabolic conversion of THX to CLO may explain these results. The NF 57 control tadpoles were heavier, longer, and more developed than the others. The progression of development from NF 57-66 was reduced by THX low, and weight gain was impaired. Liver reductases were highest in the control (84.1%), with low NEO exhibiting the greatest reductions; the greatest cytotoxicity was seen with THX high. More transcriptional activity was noted in brains than in livers. Results affirm the utility of a study approach that considers multiple complexities in ecotoxicological studies with non-target amphibians, underscoring the need for simultaneously considering NEO concentration-response relationships with both whole-organism and biomarker endpoints.


Assuntos
Encéfalo/efeitos dos fármacos , Expressão Gênica , Guanidinas/farmacologia , Fígado/efeitos dos fármacos , Neonicotinoides/farmacologia , Oxirredutases/análise , Tiametoxam/farmacologia , Tiazóis/farmacologia , Animais , Encéfalo/metabolismo , Guanidinas/toxicidade , Fígado/enzimologia , Fígado/metabolismo , Metamorfose Biológica , Neonicotinoides/toxicidade , Tiametoxam/toxicidade , Tiazóis/toxicidade , Xenopus laevis/genética , Xenopus laevis/metabolismo
2.
Int J Mol Sci ; 22(17)2021 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-34502500

RESUMO

In this paper, we review the effects of large-scale neonicotinoid contaminations in the aquatic environment on non-target aquatic invertebrate and vertebrate species. These aquatic species are the fauna widely exposed to environmental changes and chemical accumulation in bodies of water. Neonicotinoids are insecticides that target the nicotinic type acetylcholine receptors (nAChRs) in the central nervous systems (CNS) and are considered selective neurotoxins for insects. However, studies on their physiologic impacts and interactions with non-target species are limited. In researches dedicated to exploring physiologic and toxic outcomes of neonicotinoids, studies relating to the effects on vertebrate species represent a minority case compared to invertebrate species. For aquatic species, the known effects of neonicotinoids are described in the level of organismal, behavioral, genetic and physiologic toxicities. Toxicological studies were reported based on the environment of bodies of water, temperature, salinity and several other factors. There exists a knowledge gap on the relationship between toxicity outcomes to regulatory risk valuation. It has been a general observation among studies that neonicotinoid insecticides demonstrate significant toxicity to an extensive variety of invertebrates. Comprehensive analysis of data points to a generalization that field-realistic and laboratory exposures could result in different or non-comparable results in some cases. Aquatic invertebrates perform important roles in balancing a healthy ecosystem, thus rapid screening strategies are necessary to verify physiologic and toxicological impacts. So far, much of the studies describing field tests on non-target species are inadequate and in many cases, obsolete. Considering the current literature, this review addresses important information gaps relating to the impacts of neonicotinoids on the environment and spring forward policies, avoiding adverse biological and ecological effects on a range of non-target aquatic species which might further impair the whole of the aquatic ecological web.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Inseticidas/efeitos adversos , Neonicotinoides/efeitos adversos , Animais , Ecossistema , Hidrobiologia , Inseticidas/farmacologia , Invertebrados/efeitos dos fármacos , Neonicotinoides/farmacologia , Neurotoxinas/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade
3.
Int J Mol Sci ; 22(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34576043

RESUMO

The functional expression of the cockroach Pameα7 nicotinic acetylcholine receptor subunit has been previously studied, and was found to be able to form a homomeric receptor when expressed in Xenopus laevis oocytes. In this study, we found that the neonicotinoid insecticide imidacloprid is unable to activate the cockroach Pameα7 receptor, although thiacloprid induces low inward currents, suggesting that it is a partial agonist. In addition, the co-application or 5 min pretreatment with 10 µM imidacloprid increased nicotine current amplitudes, while the co-application or 5 min pretreatment with 10 µM thiacloprid decreased nicotine-evoked current amplitudes by 54% and 28%, respectively. This suggesting that these two representatives of neonicotinoid insecticides bind differently to the cockroach Pameα7 receptor. Interestingly, the docking models demonstrate that the orientation and interactions of the two insecticides in the cockroach Pameα7 nAChR binding pocket are very similar. Electrophysiological results have provided evidence to suggest that imidacloprid and thiacloprid could act as modulators of the cockroach Pameα7 receptors.


Assuntos
Inseticidas/farmacologia , Neonicotinoides/farmacologia , Antagonistas Nicotínicos/farmacologia , Nitrocompostos/farmacologia , Tiazinas/farmacologia , Animais , Baratas/efeitos dos fármacos , Agonistas Nicotínicos/farmacologia , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Técnicas de Patch-Clamp , Receptores Nicotínicos , Xenopus laevis
4.
Sci Rep ; 11(1): 15252, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315944

RESUMO

Neonicotinoids are insecticides widely used as seed treatments that appear to have multiple negative effects on birds at a diversity of biological scales. Adult birds exposed to a low dose of imidacloprid, one of the most commonly used neonicotinoids, presented reduced fat stores, delayed migration and potentially altered orientation. However, little is known on the effect of imidacloprid on birds growth rate despite studies that have documented disruptive effects of low imidacloprid doses on thyroid gland communication. We performed a [Formula: see text] factorial design experiment in Zebra finches, in which nestling birds were exposed to a very low dose (0.205 mg kg body [Formula: see text]) of imidacloprid combined with food restriction during posthatch development. During the early developmental period, imidacloprid exposure resulted in an improvement of body condition index in treated nestlings relative to controls. Imidacloprid also led to compensatory growth in food restricted nestlings. This early life neonicotinoid exposure also carried over to adult age, with exposed birds showing higher lean mass and basal metabolic rate than controls at ages of 90-800 days. This study presents the first evidence that very low-dose neonicotinoid exposure during early life can permanently alter adult phenotype in birds.


Assuntos
Neonicotinoides/farmacologia , Animais , Neonicotinoides/metabolismo , Aves Canoras/crescimento & desenvolvimento , Aves Canoras/metabolismo
5.
Molecules ; 26(14)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34299501

RESUMO

Xyleborus sp beetles are types of ambrosia beetles invasive to the United States and recently also to Mexico. The beetle can carry a fungus responsible for the Laurel Wilt, a vascular lethal disease that can host over 300 tree species, including redbay and avocado. This problem has a great economic and environmental impact. Indeed, synthetic chemists have recently attempted to develop new neonicotinoids. This is also due to severe drug resistance to "classic" insecticides. In this research, a series of neonicotinoids analogs were synthesized, characterized, and evaluated against Xyleborus sp. Most of the target compounds showed good to excellent insecticidal activity. Generally, the cyclic compounds also showed better activity in comparison with open-chain compounds. Compounds R-13, 23, S-29, and 43 showed a mortality percent of up to 73% after 12 h of exposure. These results highlight the enantioenriched compounds with absolute R configuration. The docking results correlated with experimental data which showed both cation-π interactions in relation to the aromatic ring and hydrogen bonds between the search cavity 3C79 and the novel molecules. The results suggest that these sorts of interactions are responsible for high insecticidal activity.


Assuntos
Besouros/efeitos dos fármacos , Inseticidas/síntese química , Inseticidas/farmacologia , Neonicotinoides/síntese química , Neonicotinoides/farmacologia , Gorgulhos/efeitos dos fármacos , Ambrosia/parasitologia , Animais , Besouros/microbiologia , Ericaceae/parasitologia , Fungos/patogenicidade , Ligação de Hidrogênio/efeitos dos fármacos , Doenças das Plantas/microbiologia , Árvores/parasitologia , Gorgulhos/microbiologia
6.
Gene ; 800: 145833, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34274477

RESUMO

As one of the most common benthic invertebrates in freshwater, mayflies are very sensitive to changes in water quality and have high requirements for the water environment to allow their nymphs to successfully live and grow. Neonicotinoids, such as imidacloprid, can enter fresh water and pollute the aquatic environment. The present study had two goals: (1) investigate imidacloprid effects on mayfly larvae Choroterpes (Euthralus) yixingensis, and (2) contribute to the phylogenetic status of Ephemeroptera that has always been controversial. Nymphs were collected from Jinhua, China and exposed to different concentrations imidacloprid (5, 10, 20, and 40 µg/L) in the laboratory. Survival of C. yixingensis nymphs decreased as a function of time and imidacloprid concentration with only ~ 55% survival after 72 h exposure to 40 µg/L imidacloprid. After culture under 40 µg/L imidacloprid for 24 h, the steady state transcript levels of mitochondrial COX3, ND4 and ND4L genes were reduced to just 0.07 ± 0.11, 0.30 ± 0.16, and 0.28 ± 0.13 as compared with respective control values (P < 0.01). Steady state transcript levels of ND4 and ND4L were also significantly reduced in a dose-dependent manner (P < 0.05), suggesting that the steady state transcript pattern of these genes in mayfly nymphs can change in response to different levels of environmental contamination. Hence, the mitochondrial protein-coding genes of mayflies could potentially be developed as biomarkers for water ecotoxicity monitoring in the future. In addition, we used the mitochondrial genome sequence of C. yixingensis for an assessment of the phylogenetic tree of Ephemeroptera. The monophyly of Leptophlebiidae was supported and showed that Leptophlebiidae was a sister group to the clade (Baetidae + Caenidae).


Assuntos
Ephemeroptera/genética , Expressão Gênica/efeitos dos fármacos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Animais , Ephemeroptera/efeitos dos fármacos , Genoma de Inseto , Genoma Mitocondrial , Proteínas de Insetos/genética , Inseticidas/farmacologia , Ninfa/efeitos dos fármacos , Ninfa/genética , Filogenia
7.
PLoS Biol ; 19(4): e3001190, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33844686

RESUMO

Chemical insecticides have been heavily employed as the most effective measure for control of agricultural and medical pests, but evolution of resistance by pests threatens the sustainability of this approach. Resistance-conferring mutations sometimes impose fitness costs, which may drive subsequent evolution of compensatory modifier mutations alleviating the costs of resistance. However, how modifier mutations evolve and function to overcome the fitness cost of resistance still remains unknown. Here we show that overexpression of P450s not only confers imidacloprid resistance in the brown planthopper, Nilaparvata lugens, the most voracious pest of rice, but also leads to elevated production of reactive oxygen species (ROS) through metabolism of imidacloprid and host plant compounds. The inevitable production of ROS incurs a fitness cost to the pest, which drives the increase or fixation of the compensatory modifier allele T65549 within the promoter region of N. lugens peroxiredoxin (NlPrx) in the pest populations. T65549 allele in turn upregulates the expression of NlPrx and thus increases resistant individuals' ability to clear the cost-incurring ROS of any source. The frequent involvement of P450s in insecticide resistance and their capacity to produce ROS while metabolizing their substrates suggest that peroxiredoxin or other ROS-scavenging genes may be among the common modifier genes for alleviating the fitness cost of insecticide resistance.


Assuntos
Hemípteros/efeitos dos fármacos , Resistência a Inseticidas/efeitos dos fármacos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Oryza/parasitologia , Peroxirredoxinas/fisiologia , Adaptação Biológica/efeitos dos fármacos , Adaptação Biológica/genética , Alelos , Animais , Mapeamento Cromossômico , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Genes de Insetos/efeitos dos fármacos , Genes Modificadores/efeitos dos fármacos , Genes Modificadores/fisiologia , Estudos de Associação Genética , Aptidão Genética/efeitos dos fármacos , Hemípteros/fisiologia , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Oryza/efeitos dos fármacos , Peroxirredoxinas/genética , Espécies Reativas de Oxigênio/metabolismo , Testes de Toxicidade
8.
Parasit Vectors ; 14(1): 199, 2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33849643

RESUMO

BACKGROUND: Onchocerca lupi and Cercopithifilaria spp. are vector-borne filarioids of dogs, which harbour skin microfilariae (mfs), the former being of zoonotic concern. Proper treatment studies using compounds with microfilaricidal activity have not been performed. Therefore, this study aimed to assess the efficacy of a commercially available spot-on formulation containing moxidectin 2.5%/imidacloprid 10% for the treatment of O. lupi or Cercopithifilaria spp. skin-dwelling mfs in naturally infected dogs. METHODS: Privately owned dogs (n = 393) from southern Portugal were sampled via skin biopsies to identify and count mfs in 20 µl of skin sediment. A total of 22 mfs-positive dogs were allocated to treatment group (n = 11; G1) or left untreated as a control (n = 11; G2). As a pilot investigation to test the treatment efficacy, five dogs assigned to G1 were treated four times at monthly intervals with moxidectin 2.5%/imidacloprid 10% spot-on formulation on SDs 0, 28 (± 2), 56 (± 2), and 84 (± 2). Based on the negative results for both O. lupi and/or Cercopithifilaria spp. mfs of dogs in the pilot study from SD28 onwards, the remaining six dogs in G1 were treated at SD0 and assessed only at SD28. RESULTS: Of the 393 animals sampled, 78 (19.8%) scored positive for skin-dwelling mfs. At the pilot investigation, a mean number of 19.6 mfs for O. lupi was recorded among five infected dogs whereas no mfs were detected at SD28. At SD0, the mean number of Cercopithifilaria spp. larvae was 12.6 for G1 and 8.7 for G2. The mean number of mfs for G2 was 20.09. CONCLUSIONS: Results herein obtained suggest that a single treatment with moxidectin 2.5%/imidacloprid 10% spot-on formulation is efficacious against skin-dwelling mfs in dogs. The microfilaricidal effect of moxidectin could also be useful in reducing the risk of O. lupi infection for humans.


Assuntos
Anti-Helmínticos/farmacologia , Doenças do Cão/tratamento farmacológico , Filariose/veterinária , Filarioidea/efeitos dos fármacos , Macrolídeos/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Onchocerca/efeitos dos fármacos , Oncocercose/veterinária , Animais , Anti-Helmínticos/química , Doenças do Cão/parasitologia , Cães , Composição de Medicamentos , Feminino , Filariose/tratamento farmacológico , Filariose/parasitologia , Filarioidea/crescimento & desenvolvimento , Macrolídeos/química , Masculino , Neonicotinoides/química , Nitrocompostos/química , Onchocerca/crescimento & desenvolvimento , Oncocercose/tratamento farmacológico , Oncocercose/parasitologia , Projetos Piloto , Portugal , Resultado do Tratamento
9.
Commun Biol ; 4(1): 286, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33674721

RESUMO

Voracious feeding, trans-continental migration and insecticide resistance make Spodoptera litura among the most difficult Asian agricultural pests to control. Larvae exhibit strong circadian behavior, feeding actively at night and hiding in soil during daytime. The daily pattern of larval metabolism was reversed, with higher transcription levels of genes for digestion (amylase, protease, lipase) and detoxification (CYP450s, GSTs, COEs) in daytime than at night. To investigate the control of these processes, we annotated nine essential clock genes and analyzed their transcription patterns, followed by functional analysis of their coupling using siRNA knockdown of interlocked negative feedback system core and repressor genes (SlituClk, SlituBmal1 and SlituCwo). Based on phase relationships and overexpression in cultured cells the controlling mechanism seems to involve direct coupling of the circadian processes to E-boxes in responding promoters. Additional manipulations involving exposure to the neonicotinoid imidacloprid suggested that insecticide application must be based on chronotoxicological considerations for optimal effectiveness.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/metabolismo , Ritmo Circadiano , Comportamento Alimentar , Proteínas de Insetos/metabolismo , Spodoptera/metabolismo , Animais , Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Inativação Metabólica , Proteínas de Insetos/genética , Inseticidas/farmacologia , Larva/genética , Larva/metabolismo , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Interferência de RNA , RNA-Seq , Spodoptera/efeitos dos fármacos , Spodoptera/embriologia , Spodoptera/genética , Fatores de Tempo , Transcriptoma
10.
Bioorg Med Chem Lett ; 43: 127960, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33741465

RESUMO

In the studies on dihydroxy intermediate synthesis, a serendipitous reaction of introducing nitro group from nitromethylene has been observed. Instead of expected dihydroxy compounds, dinitration structures with nitromethylene analogues were prepared under mild conditions by using a metal-free catalyst B(OH)3. In this reaction, the extra nitro group was suggested to be from starting material. Bioassays indicated that compound 3a showed good insecticidal activities against cowpea aphid (Aphis craccivora) and armyworm (Mythimna separata), with LC50 values were 4.9 mg/L and 7.1 mg/L, respectively.


Assuntos
Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Neonicotinoides/farmacologia , Animais , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Inseticidas/síntese química , Inseticidas/química , Modelos Moleculares , Estrutura Molecular , Neonicotinoides/síntese química , Neonicotinoides/química , Relação Estrutura-Atividade
11.
Insect Biochem Mol Biol ; 131: 103547, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33548485

RESUMO

Insecticides remain valuable tools for the control of insect pests that significantly impact human health and agriculture. A deeper understanding of insecticide targets is important in maintaining this control over pests. Our study systematically investigates the nicotinic acetylcholine receptor (nAChR) gene family, in order to identify the receptor subunits critical to the insect response to insecticides from three distinct chemical classes (neonicotinoids, spinosyns and sulfoximines). Applying the CRISPR/Cas9 gene editing technology in D. melanogaster, we were able to generate and maintain homozygous mutants for eight nAChR subunit genes. A ninth gene (Dß1) was investigated using somatic CRISPR in neural cells to overcome the low viability of the homozygous germline knockout mutant. These findings highlight the specificity of the spinosyn class insecticide, spinosad, to receptors containing the Dα6 subunit. By way of contrast, neonicotinoids are likely to target multiple receptor subtypes, beyond those receptor subunit combinations previously identified. Significant differences in the impacts of specific nAChR subunit deletions on the resistance level of flies to neonicotinoids imidacloprid and nitenpyram indicate that the receptor subtypes they target do not completely overlap. While an R81T mutation in ß1 subunits has revealed residues co-ordinating binding of sulfoximines and neonicotinoids differ, the resistance profiles of a deletion of Dß1 examined here provide new insights into the mode of action of sulfoxaflor (sulfoximine) and identify Dß1 as a key component of nAChRs targeted by both these insecticide classes. A comparison of resistance phenotypes found in this study to resistance reported in insect pests reveals a strong conservation of subunit targets across many different insect species and that mutations have been identified in most of the receptor subunits that our findings would predict to have the potential to confer resistance.


Assuntos
Drosophila melanogaster , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Receptores Nicotínicos , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Combinação de Medicamentos , Macrolídeos/farmacologia , Mutação , Neonicotinoides/farmacologia , Piridinas/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Compostos de Enxofre/farmacologia
12.
Trop Med Int Health ; 26(4): 469-477, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33423364

RESUMO

OBJECTIVES: To evaluate the entomological efficacy and the residual activity of indoor residual spraying with Fludora® Fusion 562.5 WP-SB, a combination formulation containing clothianidin, a neonicotinoid and deltamethrin, a pyrethroid, against the main rural malaria vector, Anopheles culicifacies s.l., in India in a small-scale trial. METHODS: In three study villages, suitable households were randomly allocated to five treatments: Fludora® Fusion 562.5 WP-SB (target dose 225 mg active ingredient AI/m2 ); clothianidin 70 WG (target dose 200 mg AI/m2 ); K-Othrine 250 WG (deltamethrin, target dose 25 mg AI/m2 ); Ficam VC 80 WP-SB (bendiocarb, target dose 400 mg AI/m2 ) and unsprayed control. Insecticides were sprayed by hand compression sprayers with control flow valves and 8002E nozzles. Post-spray cone bioassays were done on insecticide-treated walls using a colonised, deltamethrin-resistant strain of An. culicifacies. Mosquitoes were collected from treated rooms by different methods. The insecticide content on filter papers collected from the sprayed walls was determined by chemical assay to assess the spray quality. RESULTS: The ratios of applied to target doses of insecticides were within 0.84 to 1.4, showing a good spray quality. The cone bioassays revealed residual action lasting 7 months for all insecticides without significant differences in mortality between different surfaces treated nor between the four treatment arms (P > 0.05). Considering all entomological parameters such as indoor resting density, excito-repellency, blood-feeding inhibition and delayed mortality, the overall efficacy of Fludora® Fusion WG-SB was equal or better compared with other insecticides. CONCLUSIONS: Fludora® Fusion showed overall equal or better efficacy than deltamethrin and bendiocarb alone against a pyrethroid-resistant malaria vector population and can be considered as an alternative product for management of pyrethroid resistance in malaria vectors.


Assuntos
Anopheles/efeitos dos fármacos , Culicidae/efeitos dos fármacos , Características da Família , Inseticidas/farmacologia , Malária , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Animais , Bioensaio , Guanidinas/farmacologia , Humanos , Resistência a Inseticidas , Malária/prevenção & controle , Malária/transmissão , Neonicotinoides/farmacologia , Nitrilas/farmacologia , Piretrinas/farmacologia , Tiazóis/farmacologia
13.
J Agric Food Chem ; 69(5): 1455-1465, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33497218

RESUMO

In this research, six neonicotinoid analogs derived from l-proline were synthesized, characterized, and evaluated as insecticides against Xyleborus affinis. Most of the target compounds showed good to excellent insecticidal activity. To the best of our knowledge, this is the first report dealing with the use of enantiopure l-proline to get neonicotinoids. These results highlighted the compound 9 as an excellent candidate used as the lead chiral insecticide for future development. Additionally, molecular docking with the receptor and compound 9 was carried out to gain insight into its high activity when compared to dinotefuran. Finally, the neurotoxic evaluation of compound 9 showed lower toxicity than the classic neonicotinoid dinotefuran.


Assuntos
Inseticidas/síntese química , Neonicotinoides/síntese química , Prolina/química , Animais , Besouros/efeitos dos fármacos , Besouros/crescimento & desenvolvimento , Inseticidas/química , Inseticidas/farmacologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Neonicotinoides/química , Neonicotinoides/farmacologia
14.
J Agric Food Chem ; 69(2): 638-645, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33398988

RESUMO

With widespread applications of the latest neonicotinoid in agriculture, dinotefuran has gradually become a hazardous contaminant for plants through the generation of excessive reactive oxygen species. However, the potential toxic mechanisms of oxidative damages to plants induced by dinotefuran are still unknown. As a core component of the glutathione antioxidant enzyme system, glutathione peroxidases have been used as biomarkers to reflect excessive oxidative stress. In this study, the hazardous effects of dinotefuran on AtGPX6 were investigated at the molecular level. The intrinsic fluorescence intensity of AtGPX6 was quenched using the static quenching mechanism upon binding with dinotefuran. Moreover, a single binding site was predicted for AtGPX6 toward dinotefuran, and the complex formation was presumed to be driven by hydrogen bonds or van der Waals forces, which conformed with the molecular docking results. In addition, AtGPX6 exhibited moderate binding affinity with dinotefuran based on the bio-layer interferometry assay. In addition, the loosening and unfolding of the protein skeleton of AtGPX6 with the addition of dinotefuran were explored along with the increase of hydrophobicity around tryptophan residues. Lastly, the toxic effects of dinotefuran on the root growth of Arabidopsis seedlings were also examined. The exploration of the binding mechanism of dinotefuran with AtGPX6 at the molecular level would provide the toxicity assessment of dinotefuran on plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/enzimologia , Guanidinas/farmacologia , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/metabolismo , Arabidopsis/química , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Sítios de Ligação , Inseticidas/química , Simulação de Acoplamento Molecular , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/química , Fosfolipídeo Hidroperóxido Glutationa Peroxidase/genética , Plântula/química , Plântula/efeitos dos fármacos , Plântula/enzimologia , Plântula/genética
15.
Sci Rep ; 11(1): 2061, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479461

RESUMO

Globally, neonicotinoids are the most used insecticides, despite their well-documented sub-lethal effects on beneficial insects. Neonicotinoids are nicotinic acetylcholine receptor agonists. Memory, circadian rhythmicity and sleep are essential for efficient foraging and pollination and require nicotinic acetylcholine receptor signalling. The effect of field-relevant concentrations of the European Union-banned neonicotinoids: imidacloprid, clothianidin, thiamethoxam and thiacloprid were tested on Drosophila memory, circadian rhythms and sleep. Field-relevant concentrations of imidacloprid, clothianidin and thiamethoxam disrupted learning, behavioural rhythmicity and sleep whilst thiacloprid exposure only affected sleep. Exposure to imidacloprid and clothianidin prevented the day/night remodelling and accumulation of pigment dispersing factor (PDF) neuropeptide in the dorsal terminals of clock neurons. Knockdown of the neonicotinoid susceptible Dα1 and Dß2 nicotinic acetylcholine receptor subunits in the mushroom bodies or clock neurons recapitulated the neonicotinoid like deficits in memory or sleep/circadian behaviour respectively. Disruption of learning, circadian rhythmicity and sleep are likely to have far-reaching detrimental effects on beneficial insects in the field.


Assuntos
Ritmo Circadiano/efeitos dos fármacos , Memória/efeitos dos fármacos , Receptores Nicotínicos/genética , Sono/efeitos dos fármacos , Animais , Ritmo Circadiano/genética , Drosophila melanogaster/efeitos dos fármacos , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Guanidinas/farmacologia , Inseticidas/efeitos adversos , Inseticidas/farmacologia , Memória/fisiologia , Neonicotinoides/efeitos adversos , Neonicotinoides/farmacologia , Neuropeptídeos/genética , Agonistas Nicotínicos/farmacologia , Nitrocompostos/farmacologia , Sono/genética , Tiametoxam/farmacologia , Tiazinas/farmacologia , Tiazóis/farmacologia
16.
Environ Geochem Health ; 43(5): 1941-1952, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33201396

RESUMO

In this case, the dissipation and residues of imidacloprid as well as its control efficacy against aphids (Aphis gossypii Glover) in cotton cropping system were reported. After the final spray at the rates of 10.5-42.5 g a.i. ha-1, the initial deposits were 0.59-2.25 mg kg-1 with half-lives of 2.12-2.84 days on leaves and 0.06-0.21 mg kg-1 with half-lives of 1.51-4.20 days in soil, respectively. The initial residues were significantly higher with longer persistence in the upper position of the leaf than in middle and lower positions. The different application dosages could induce a significant difference in the initial deposits, but not show consistent correlation with the dissipation rate. The repeated applications of imidacloprid could alter its residue levels and dissipation rates. The long-term residue concentrations of imidacloprid (60 days after the final application) reached to the nondetectable level in soil. Combined with the control efficacy results, it was considered that the recommended dose of imidacloprid on cotton could be used effectively and safe in this arid area from the view of crop protection and environmental contamination.


Assuntos
Afídeos/efeitos dos fármacos , Gossypium/efeitos dos fármacos , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Animais , Biodegradação Ambiental , China , Meia-Vida , Controle de Insetos/métodos , Inseticidas/análise , Inseticidas/farmacocinética , Neonicotinoides/análise , Neonicotinoides/farmacocinética , Nitrocompostos/análise , Nitrocompostos/farmacocinética , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/farmacocinética , Folhas de Planta/efeitos dos fármacos , Poluentes do Solo/análise , Poluentes do Solo/farmacocinética
17.
Food Chem ; 339: 127985, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920305

RESUMO

There is limited research focusing on the effects of human gut microbiota on the oral bioaccessibility and intestinal absorption of pesticide residues in food. In the present study, we use a modified setup of the Simulator of the Human Intestinal Microbial Ecosystem for the determination of pesticide residue bioaccessibility in Chaenomeles speciosa, and a Caco-2 cell model of human intestinal absorption. Results showed that gut microbiota played a dual role based their effects on contaminant release and metabolism in the bioaccessibility assay, and Lactobacillus plantarum was one of key bacterial species in the gut microbiota that influenced pesticide stability significantly. The addition of L. plantarum to the system reduced the relative amounts (by 11.40-86.51%) of six pesticides. The interaction between the food matrix and human gut microbiota led to different absorption rates, and the barrier effects increased with an increase in incubation time.


Assuntos
Microbioma Gastrointestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Praguicidas/farmacologia , Rosaceae/química , Bactérias/metabolismo , Células CACO-2 , Humanos , Mucosa Intestinal/citologia , Mucosa Intestinal/microbiologia , Lactobacillus plantarum/efeitos dos fármacos , Lactobacillus plantarum/isolamento & purificação , Neonicotinoides/metabolismo , Neonicotinoides/farmacologia , Nitrocompostos/metabolismo , Nitrocompostos/farmacologia , Compostos Organotiofosforados/metabolismo , Compostos Organotiofosforados/farmacologia , Praguicidas/química , Praguicidas/metabolismo , Rosaceae/metabolismo , Tiametoxam/metabolismo , Tiametoxam/farmacologia
18.
J Comput Chem ; 42(5): 293-302, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33232540

RESUMO

Drug binding to a protein target is governed by a complex pattern of noncovalent interactions between the ligand and the residues in the protein's binding pocket. Here we introduce a generally applicable, parameter-free, computational method that allows for the identification, quantification, and analysis of the key ligand-residue interactions responsible for molecular recognition. Our strategy relies on Local Energy Decomposition analysis at the "gold-standard" coupled cluster DLPNO-CCSD(T) level. In the study case shown in this paper, nicotine and imidacloprid binding to the nicotinic acetylcholine receptor, our approach provides new insights into how individual amino acids in the active site determine sensitivity and selectivity of the ligands, extending and refining classical pharmacophore hypotheses. By inference, the method is applicable to any kind of host/guest interactions with potential applications in industrial biocatalysis and protein engineering.


Assuntos
Neonicotinoides/farmacologia , Agonistas Nicotínicos/farmacologia , Nitrocompostos/farmacologia , Teoria Quântica , Receptores Nicotínicos/efeitos dos fármacos , Ligantes , Neonicotinoides/metabolismo , Agonistas Nicotínicos/metabolismo , Nitrocompostos/metabolismo , Ligação Proteica , Receptores Nicotínicos/metabolismo , Termodinâmica
19.
Pestic Biochem Physiol ; 171: 104741, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33357563

RESUMO

Insecticide resistance in pest populations is an increasing problem in both urban and rural settings due to over-application of insecticides and lack of rotation among insecticidal chemical classes. The house fly (Musca domestica L.) is a cosmopolitan pest fly species implicated in the transmission of numerous pathogens. The evolution of insecticide resistance long has been documented in house flies, with resistance reported to all major insecticide classes. House fly resistance to imidacloprid, the most widely used neonicotinoid insecticide available for fly control, has evolved in field populations through both physiological and behavioral mechanisms. Previous studies have characterized and mapped the genetic changes that confer physiological resistance to imidacloprid, but no study have examined the genetics involved in behavioral resistance to imidacloprid to date. In the current study, several approaches were utilized to characterize the genetics and inheritance of behavioral resistance to imidacloprid in the house fly. These include behavioral observation analyses, preference assays, and the use of genetic techniques for the identification of house fly chromosome(s) carrying factors. Behavioral resistance was mapped to autosomes 1 and 4. Inheritance of resistance was shown to be neither fully dominant nor recessive. Factors on autosomes 1 and 4 independently conferred contact-dependent avoidance of imidacloprid and a feeding preference for sugar alone or for sugar with dinotefuran, another neonicotinoid insecticide, over imidacloprid. This study serves as the first linkage analysis of a behavioral trait in the house fly, and provides new avenues for research regarding inherited behavior in the house fly and other animals.


Assuntos
Moscas Domésticas , Inseticidas , Animais , Moscas Domésticas/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos
20.
Genome ; 64(5): 567-579, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33242262

RESUMO

Recent studies indicate that thiamethoxam (TMX), a neonicotinoid insecticide, can affect plant responses to environmental stressors, such as neighboring weeds. The molecular mechanisms behind both stable and environmentally specific responses to TMX likely involve genes related to defense and stress responses. We investigated the effect of a TMX seed treatment on global gene expression in maize coleoptiles both under normal conditions and under low ratio red to far-red (R:FR) light stress induced by the presence of neighboring plants. The neighboring plant treatment upregulated genes involved in biotic and abiotic stress responses and affected specific photosynthesis and cell-growth related genes. Low R:FR light may enhance maize resistance to herbivores and pathogens. TMX appears to compromise resistance. The TMX treatment stably repressed many genes that encode proteins involved in biotic stress responses, as well as cell-growth genes. Notably, TMX effects on many genes' expression were conditional on the environment. In response to low R:FR, plants treated with TMX engage genes in the JA pathway, as well as other stress-related response pathways. Neighboring weeds may condition TMX-treated plants to become more stress tolerant.


Assuntos
Inseticidas/farmacologia , Neonicotinoides/farmacologia , Estresse Fisiológico/genética , Tiametoxam/farmacologia , Zea mays/efeitos dos fármacos , Zea mays/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Daninhas/efeitos dos fármacos , Sementes/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/fisiologia
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