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1.
Chemosphere ; 254: 126779, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957265

RESUMO

Pyrethroids are a class of highly effective, broad-spectrum, less toxic, biodegradable synthetic pesticides. However, despite the extremely wide application of pyrethroids, there are many problems, such as insecticide resistance, lethal/sub-lethal toxicity to mammals, aquatic organisms or other beneficial organisms. The objectives of this review were to cover the main structures, synthesis, steroisomers, mechanisms of action, anti-mosquito activities, resistance, photodegradation and toxicities of pyrethroids. That was to provide a reference for synthesizing or screening novel pyrethroids with low insecticide resistance and low toxicity to beneficial organisms, evaluating the environmental pollution of pyrethroids and its metabolites. Besides, pyrethroids are mainly used for the control of vectors such as insects, and the non-target organisms are mammals, aquatic organisms etc. While maintaining the insecticidal activity is important, its toxic effects on non-target organisms should be also considered. Pyrethroid resistance is present not only in insect mosquitoes but also in environmental microorganisms, which results in anti-pyrethroids resistance (APR) strains. Besides, photodegradation product dibenzofurans is harmful to mammals and environment. Additionally, pyrethroid metabolites may have higher hormonal interference than the parents. Particularly, delivery of pyrethroids in nanoform can reduce the discharge of more toxic substances (such as organic solvents, etc.) to the environment.


Assuntos
Inseticidas/toxicidade , Piretrinas/toxicidade , Animais , Culicidae/efeitos dos fármacos , Resistência a Inseticidas/fisiologia , Inseticidas/química , Inseticidas/metabolismo , Mosquitos Vetores , Fotólise , Piretrinas/química , Piretrinas/metabolismo
2.
Toxicol Appl Pharmacol ; 401: 115093, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526215

RESUMO

Breast cancer incidence is increasing globally and pesticides exposure may impact risk of developing this disease. Hexachlorobenzene (HCB) and chlorpyrifos (CPF) act as endocrine disruptors, inducing proliferation in breast cancer cells. Vascular endothelial growth factor-A (VEGF-A), cyclooxygenase-2 (COX-2) and nitric oxide (NO) are associated with angiogenesis. Our aim was to evaluate HCB and CPF action, both weak aryl hydrocarbon receptor (AhR) ligands, on angiogenesis in breast cancer models. We used: (1) in vivo xenograft model with MCF-7 cells, (2) in vitro breast cancer model with MCF-7, and (3) in vitro neovasculogenesis model with endothelial cells exposed to conditioned medium from MCF-7. Results show that HCB (3 mg/kg) and CPF (0.1 mg/kg) stimulated vascular density in the in vivo model. HCB and CPF low doses enhanced VEGF-A and COX-2 expression, accompanied by increased levels of nitric oxide synthases (NOS), and NO release in MCF-7. HCB and CPF high doses intensified VEGF-A and COX-2 levels but rendered different effects on NOS, however, both pesticides reduced NO production. Moreover, our data indicate that HCB and CPF-induced VEGF-A expression is mediated by estrogen receptor and NO, while the increase in COX-2 is through AhR and NO pathways in MCF-7. In conclusion, we demonstrate that HCB and CPF environmental concentrations stimulate angiogenic switch in vivo. Besides, pesticides induce VEGF-A and COX-2 expression, as well as NO production in MCF-7, promoting tubulogenesis in endothelial cells. These findings show that pesticide exposure could stimulate angiogenesis, a process that has been demonstrated to contribute to breast cancer progression.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Clorpirifos/metabolismo , Hexaclorobenzeno/metabolismo , Neovascularização Patológica/induzido quimicamente , Neovascularização Patológica/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Células A549 , Animais , Clorpirifos/toxicidade , Relação Dose-Resposta a Droga , Feminino , Fungicidas Industriais/metabolismo , Fungicidas Industriais/toxicidade , Hexaclorobenzeno/toxicidade , Humanos , Inseticidas/metabolismo , Inseticidas/toxicidade , Ligantes , Células MCF-7 , Camundongos , Camundongos Nus , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
3.
Chemosphere ; 257: 127162, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32485514

RESUMO

Deltamethrin is used widely in Eriocheir sinensis aquaculture to remove wild fish and parasites. The residual deltamethrin greatly affects the growth and quality of E. sinensis. In this study, the LC50 of deltamethrin against E. sinensis at 24, 48 and 96 h was determined to be 6.5, 5.0 and 2.8 µg/L, respectively. The enzyme activity and gene transcription of SOD, CAT, and PO in the hepatopancreas of E. sinensis after deltamethrin stimulation showed an increasing tendency, and these enzymes reached their maximum activities at 6-10 d. The MDA content accumulated with increased time of deltamethrin stress. After 15 d of deltamethrin stress, the hepatopancreas of E. sinensis was found to be damaged based on HE staining. These results showed that deltamethrin is highly toxic to E. sinensis. But the half-life of deltamethrin is long and mainly relies on biodegradation. To resolve the pollution of residual deltamethrin, a strain of deltamethrin-degrading bacteria, P-2, was isolated from the sediment of an E. sinensis culture pond. Through morphological observation, physiological and biochemical identification and 16S rDNA sequence analysis, we found that this strain belonged to Paracoccus sp. When the pH was 7, the substrate concentration was low, the inoculation amount was high, and the deltamethrin degradation effect of Paracoccus sp. P-2 was good. The deltamethrin residue in the hepatopancreas and muscle of E. sinensis decreased significantly when Paracoccus sp. P-2 was added at 6.0 × 108 CFU/L. The degradation efficiency of Paracoccus sp. P-2 in the hepatopancreas and muscle was more than 70%. These results showed that Paracoccus sp. P-2, the first deltamethrin-degrading bacterium in aquaculture, could be used to remove residual deltamethrin and improve the food safety of E. sinensis.


Assuntos
Braquiúros/fisiologia , Inseticidas/toxicidade , Nitrilos/toxicidade , Piretrinas/toxicidade , Animais , Aquicultura , Bactérias , Biodegradação Ambiental , Braquiúros/metabolismo , Hepatopâncreas/metabolismo , Inseticidas/metabolismo , Dose Letal Mediana , Nitrilos/metabolismo , Paracoccus/genética , Paracoccus/isolamento & purificação , Paracoccus/metabolismo , Polímeros , Piretrinas/metabolismo
4.
Chemosphere ; 259: 127419, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593003

RESUMO

Carbofuran is one of the most toxic broad-spectrum and systemic N-methyl carbamate pesticide, which is extensively applied as insecticide, nematicide and acaricide for agricultural, domestic and industrial purposes. It is extremely lethal to mammals, birds, fish and wildlife due to its anticholinesterase activity, which inhibits acetyl-cholinesterase and butyrylcholinesterse activity. In humans, carbofuran is associated with endocrine disrupting activity, reproductive disorders, cytotoxic and genotoxic abnormalities. Therefore, cleanup of carbofuran-contaminated environments is of utmost concern and urgently needs an adequate, advanced and effective remedial technology. Microbial technology (bacterial, fugal and algal species) is a very potent, pragmatic and ecofriendly approach for the removal of carbofuran. Microbial enzymes and their catabolic genes exhibit an exceptional potential for bioremediation strategies. To understand the specific mechanism of carbofuran degradation and involvement of carbofuran hydrolase enzymes and genes, highly efficient genomic approaches are required to provide reliable information and unfold metabolic pathways. This review briefly discusses the carbofuran toxicity and its toxicological impact into the environment, in-depth understanding of carbofuran degradation mechanism with microbial strains, metabolic pathways, molecular mechanisms and genetic basis involved in degradation.


Assuntos
Biodegradação Ambiental , Carbofurano/toxicidade , Inibidores da Colinesterase/toxicidade , Poluentes Ambientais/toxicidade , Acetilcolinesterase/metabolismo , Animais , Carbamatos , Carbofurano/metabolismo , Inibidores da Colinesterase/metabolismo , Poluentes Ambientais/metabolismo , Humanos , Hidrolases , Inseticidas/metabolismo , Inseticidas/toxicidade , Redes e Vias Metabólicas
5.
Environ Health ; 19(1): 49, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393266

RESUMO

BACKGROUND: Children are exposed to p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) through placental and lactational transfer. Some studies have suggested that early-life exposure to these compounds could lead to increased body mass index (BMI) during childhood. Our aim was to assess whether children's exposure during the first 2 years of life is associated with BMI z-score in Japanese children at 42 months of age. METHODS: We used data from a birth cohort (n = 290) of the Tohoku Study of Child Development. p,p'-DDT and p,p'-DDE levels were measured in breast milk samples collected 1 month after birth, and levels in children were estimated using a toxicokinetic model for three exposure periods (0-6 months, 6-12 months, 12-24 months). Associations between exposure estimates and BMI z-score at 42 months of age were assessed using multivariate linear regression models. RESULTS: We found no significant association between levels of p,p'-DDT measured in breast milk or estimated in children and BMI z-score. However, we observed associations between estimated p,p'-DDE levels in girls during all postnatal exposure periods and BMI z-score; for each log increase in the estimated p,p'-DDE levels, BMI z-score increased by 0.23 (C.I. 95%: 0.01, 0.45) for the 0-6 months exposure period, 0.26 (C.I. 95%: 0.06, 0.47) for the 6-12 months exposure period, and 0.24 (C.I. 95%: 0.05, 0.43) for the 12-24 months exposure period. CONCLUSION: In this study of Japanese children, estimated postnatal p,p'-DDE levels were associated with increased BMI z-score at 42 months of age, mostly in girls. These results are in line with previous studies supporting that early-life exposure to p,p'-DDE may be associated with higher BMI during childhood.


Assuntos
Índice de Massa Corporal , DDT/metabolismo , Diclorodifenil Dicloroetileno/metabolismo , Exposição Ambiental , Poluentes Ambientais/metabolismo , Leite Humano/química , Desenvolvimento Infantil , Pré-Escolar , Feminino , Humanos , Inseticidas/metabolismo , Japão , Estudos Longitudinais , Masculino
6.
Chemosphere ; 253: 126698, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32302901

RESUMO

Organophosphates insecticides (OPs) are one of the major environmental pollutants and their interaction with human serum albumin (HSA) has been shown to have significant effects on their bioavailability which is related to toxicokinetics and toxicodynamics in human body. In this research, solid-phase microextraction methods were developed to analyse the free concentrations of three OPs (chlorpyrifos, parathion-methyl and malathion) in buffered HSA solution and that provide a useful method for the determination of binding affinity constants (Ka), binding forces and binding location. Polydimethylsiloxane fibers were selected for analysing the free concentrations of OPs, with an external calibration approach. Good linearities conducted in PBS solution were observed in the range of 0.0025-1.7 µmol L-1 (R2 = 0.9975) for chlorpyrifos, 1.0-27 µmol L-1 (R2 = 0.9974) for parathion-methyl, and 0.5-70 µmol L-1 (R2 = 0.9973)for malathion, respectively. The LODs for instrument response were 1 ng, 5 ng and 10 ng for chlorpyrifos, parathion-methyl and malathion, respectively. The Ka values for chlorpyrifos, parathion-methyl and malathion showed that they were positively correlated with hydrophobicity and negatively correlated with temperature. The OP binding sites on HSA were confirmed by site marker competition test and further proven by computational approaches. The recognition region of parathion-methyl was situated within residues 199-292 in subdomain IIA. Malathion bonded to residues 404-558 in subdomain IIIA. The mode of action between HSA-parathion-methyl and HSA-malathion is found to involve mainly by H-bonds, π-π stacking and hydrophobic effects. These results clearly demonstrate the noncovalent binding of OPs with HSA and provide new insight into solid-phase microextraction, thermodynamics and computational approaches.


Assuntos
Inseticidas/toxicidade , Compostos Organofosforados/toxicidade , Clorpirifos , Dimetilpolisiloxanos , Humanos , Inseticidas/química , Inseticidas/metabolismo , Malation/análise , Metil Paration , Compostos Organofosforados/química , Compostos Organofosforados/metabolismo , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Microextração em Fase Sólida , Temperatura , Termodinâmica
7.
Chemosphere ; 254: 126837, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32339803

RESUMO

An improved understanding of imidacloprid (IMI) metabolism and accumulation in casing soil or compost-mushroom systems will help to optimise the safe use of IMI for agricultural pest control in Agaricus bisporus cultivation. In this study, the dissipation, metabolites and accumulation of IMI in casing soil or compost-A. bisporus systems were investigated. The results show that the IMI dissipation half-lives at doses of 10 and 50 mg kg-1 were 65 d and 59 d in casing soil and 6.6 d and 6.2 d in compost, respectively during the cultivation period. Three IMI metabolites were observed in casing soil during cultivation of mushrooms. Urea-imidacloprid (IMI-urea) was a major metabolite, accounting for more than 59%. In compost, the main metabolite in the first 5 days was IMI-urea, from 5 to 10 days olefin-imidacloprid (IMI-ole) and 6-chloronicotinic acid (6-CNA) were both the most prominent compounds, and after 10 days 6-CNA alone. At 50 mg kg-1 dose, IMI and the metabolites (IMI-urea, IMI-ole) were detected in the fruiting body with IMI applied to casing soil and only the metabolite 6-CNA was detected in fruiting body with IMI applied to compost. The bio concentration factors (BCFs) of IMI-ole and IMI-urea were higher than of IMI and 6-CNA, and the BCFs had no obvious relationship with log Kow. Furthermore, the potential dietary risk of IMI in A. bisporus was acceptable when application rates in casing soil or compost was up to 50 mg kg-1. Our study supports a safe use of IMI as agricultural pest control in A. bisporus cultivation.


Assuntos
Agaricus/metabolismo , Inseticidas/metabolismo , Neonicotinoides/metabolismo , Nitrocompostos/metabolismo , Agricultura , Compostagem , Dieta , Exposição Dietética/estatística & dados numéricos , Frutas , Medição de Risco , Solo
8.
Nat Commun ; 11(1): 1153, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32123169

RESUMO

Cyt1Aa is the one of four crystalline protoxins produced by mosquitocidal bacterium Bacillus thuringiensis israelensis (Bti) that has been shown to delay the evolution of insect resistance in the field. Limiting our understanding of Bti efficacy and the path to improved toxicity and spectrum has been ignorance of how Cyt1Aa crystallizes in vivo and of its mechanism of toxicity. Here, we use serial femtosecond crystallography to determine the Cyt1Aa protoxin structure from sub-micron-sized crystals produced in Bti. Structures determined under various pH/redox conditions illuminate the role played by previously uncharacterized disulfide-bridge and domain-swapped interfaces from crystal formation in Bti to dissolution in the larval mosquito midgut. Biochemical, toxicological and biophysical methods enable the deconvolution of key steps in the Cyt1Aa bioactivation cascade. We additionally show that the size, shape, production yield, pH sensitivity and toxicity of Cyt1Aa crystals grown in Bti can be controlled by single atom substitution.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Endotoxinas/química , Endotoxinas/metabolismo , Proteínas Hemolisinas/química , Proteínas Hemolisinas/metabolismo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Membrana Celular/efeitos dos fármacos , Cristalografia por Raios X , Dissulfetos/química , Endotoxinas/genética , Endotoxinas/farmacologia , Células HEK293 , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Inseticidas/química , Inseticidas/metabolismo , Inseticidas/farmacologia , Camundongos , Microscopia de Força Atômica , Células NIH 3T3 , Conformação Proteica , Células Sf9
9.
Chemosphere ; 249: 126167, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32062203

RESUMO

Honeydew production is a characteristic of soft scales and other hemipteran insects. Honeydew has the capacity to alter the ecology of predators and parasitoids because it is used as a food resource and can contain insecticidal proteins from hemipteran host plants. We examined honeydew excreted by the striped pine scale (Hemiptera: Coccidae), Toumeyella pini (King), after feeding on pine trees treated with systemic insecticides to determine whether they could eliminate insecticidal compounds in honeydew. Imidacloprid and spirotetramat were applied at labeled rates to soil or foliage. Water sensitive paper was used to measure honeydew production and liquid chromatography coupled to mass spectrometry (LC-MS) to analyze excreted insecticide concentrations. Foliar and soil applications of imidacloprid caused a 25-fold reduction honeydew produced by scales six days after treatment (DAT). In contrast, spirotetramat treatments did not affect honeydew production. Parent compounds of both insecticides were detected in honeydew. However, on imidacloprid treated plants, these compounds were detected at similar concentrations in honeydew collected at 4 DAT from soil and foliar treatments. Imidacloprid was only detected from soil treatments at 8 DAT. Similarly, the spirotetramat parent compound was found 4 DAT after soil and foliar treatments, but only at 8 DAT in foliar treatments. At this time the concentration of spirotetramat in honeydew was six-fold higher than at 4 DAT. We conclude that striped pine scales excrete insecticides in honeydew even when the toxicant greatly reduces honeydew production. Honeydew excretion is thus a mechanism of bioaccumulation and has the potential to harm honeydew-feeding organisms.


Assuntos
Hemípteros/metabolismo , Inseticidas/metabolismo , Animais , Compostos Aza , Imidazóis/análise , Imidazóis/metabolismo , Insetos , Inseticidas/análise , Neonicotinoides/metabolismo , Nitrocompostos/metabolismo , Pinus , Solo , Compostos de Espiro
10.
J Med Microbiol ; 69(3): 361-371, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32043956

RESUMO

Pseudomonas chlororaphis isolates have been studied intensively for their beneficial traits. P. chlororaphis species function as probiotics in plants and fish, offering plants protection against microbes, nematodes and insects. In this review, we discuss the classification of P. chlororaphis isolates within four subspecies; the shared traits include the production of coloured antimicrobial phenazines, high sequence identity between housekeeping genes and similar cellular fatty acid composition. The direct antimicrobial, insecticidal and nematocidal effects of P. chlororaphis isolates are correlated with known metabolites. Other metabolites prime the plants for stress tolerance and participate in microbial cell signalling events and biofilm formation among other things. Formulations of P. chlororaphis isolates and their metabolites are currently being commercialized for agricultural use.


Assuntos
Anti-Infecciosos/metabolismo , Biofilmes/crescimento & desenvolvimento , Fenazinas/metabolismo , Plantas/microbiologia , Probióticos , Pseudomonas chlororaphis/classificação , Acil-Butirolactonas/metabolismo , Agricultura , Antinematódeos/metabolismo , Cianeto de Hidrogênio/metabolismo , Inseticidas/metabolismo , Fenótipo , Plantas/imunologia , Pseudomonas chlororaphis/química , Pseudomonas chlororaphis/crescimento & desenvolvimento , Pseudomonas chlororaphis/fisiologia , Pirrolnitrina/metabolismo , Resorcinóis/metabolismo , Sideróforos/metabolismo , Compostos Orgânicos Voláteis/metabolismo
11.
Ecotoxicol Environ Saf ; 192: 110290, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32058164

RESUMO

The widespread use of pesticides has been one of the major anthropogenic sources of environmental pollution. Organophosphorus (OP) pesticides are predominantly used in agriculture due to their broad-spectrum insecticidal activity and chemical stability. The study was focused on the biodegradation of OP pesticides, Profenofos (PF) and Quinalphos (QP) in culture media using bacterium isolated from wetland paddy rhizosphere. The strain VITPSCQ3 showed higher pesticide tolerance, efficient biofilm formation and was capable of synthesizing organophosphate degrading enzymes. Based on the 16S rRNA gene sequencing the isolate exhibited maximum sequence similarity with Kosakinia oryzae (GenBank accession number: KR149275). Biodegradation assay with various concentrations of PF and QP (200, 400, 600 and 800 mg L-1) showed maximum degradation up to 82% and 92% within 48 h. The kinetic studies revealed the biodegradation rates (k) to be 0.0844 min-1 and 0.107 min-1 with half-lives (h) of 18 h and 14.8 h for PF and QP. The degradation products were identified by GCMS and possible degradation pathways were proposed using Insilico techniques. To the best of our knowledge, this is the first report on the biodegradation of PF and QP using Kosakonia oryzae. Bioremoval of PF and QP from aqueous solution was performed using the biofilm of VITPSCQ3 developed on selected substrates in a circulating Vertical-flow packed-bed biofilm (VFPBB) bioreactor. Charcoal, gravel and mushroom (Agaricus bisporus) were used as biofilm carriers. Mushroom showed strong biofilm formation with optimum biodegradation capacity of up to 96% for PF and 92% for QP within 120 min reaction time.


Assuntos
Biofilmes/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Enterobacteriaceae/enzimologia , Poluentes Ambientais/metabolismo , Inseticidas/metabolismo , Organotiofosfatos/metabolismo , Compostos Organotiofosforados/metabolismo , Biodegradação Ambiental , Enterobacteriaceae/genética , Enterobacteriaceae/fisiologia , Cinética , Rizosfera
12.
Chemosphere ; 247: 125948, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32069723

RESUMO

The present study explores the rapid chlopyrifos (CPs) biodegradation potential of plant growth promoting (PGP) psychrophilic bacteria isolated from brackish water by enrichment culture technique. Based on biochemical tests and 16 S rDNA sequencing the isolate was identified as Shewanella sp. The isolate Shewanella BT05 showed significant growth rate in various concentrations of (10-50 mg/L) CPs. The isolate produced plant growth promoting factors, IAA (20.8 ± 1.2 and 15.4 ± 1.0 µg/mL) and siderophores (60.67 ± 1.2 and 57.5 ± 0.9%) in the absence and presence of CPs. Further, the isolate BT05 solublized phosphate (16.5 ± 1.0 and 12.0 ± 1.0 mm in size respectively), and produce hydrogen cyanide (excellent and moderate) in the presence and absence of CPs. The isolate BT05 degraded 94.3, 91.8, 87.9, 82.6, and 80.5% of CPs at 10, 20, 30, 40, and 50 mg/L, respectively, within 24 h. Further, the media conditions were optimized for enhanced CPs removal and observed 93% removal in the presence of 3.5% glucose in pH 7.0 at 32.5 °C. Fourier-transform infrared spectroscopy and high-performance liquid chromatography results indicated the role for Shewanella BT05 in the biomineralization of CPs. The results suggested the isolate BT05 could be used for CPs removal as well as PGP activity in contaminated soil.


Assuntos
Biodegradação Ambiental , Clorpirifos/metabolismo , Inseticidas/metabolismo , Shewanella/metabolismo , Praguicidas/análise , Praguicidas/metabolismo , Fosfatos/análise , Desenvolvimento Vegetal , Plantas/metabolismo , Shewanella/isolamento & purificação , Sideróforos/metabolismo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo
13.
J Agric Food Chem ; 68(8): 2539-2546, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32023056

RESUMO

The rice planthopper is a very important hemipteran pest that preys on rice and substantially affects the safety of rice production. Moreover, the long-term prevention and control of these pests with chemical pesticides has led to an increase in the resistance of the rice planthopper as well as serious environmental pollution and food safety problems. Bacillus thuringiensis (Bt) has been used for the efficient and green control of a variety of rice pests. Therefore, based on the high-throughput screening of Bt strains that are active against the rice planthopper, we found that Bt strain B4F11 showed certain insecticidal activity against Laodelphax striatellus Fallén, and we have identified a novel insecticidal protein Cry78Ba1 from the Bt strain B4F11, which is expected to provide the specific and safe control of the rice planthopper. The Cry78Ba1 protein is composed of 380 amino acid residues with a molecular weight of 42.55 kDa and contains conserved Ricin_B_Lectin and Toxin_10 superfamily domains. It displays high insecticidal activity against L. striatellus with a lethal concentration (LC50) of 9.723 µg/mL. More importantly, this Toxin_10-like protein does not display sequence homology to any known allergen and can be degraded and inactivated rapidly when heated at 90 °C and in simulated gastrointestinal fluid. In summary, Cry78Ba1 has great potential for applications in the efficient and safe prevention and control of the rice planthopper.


Assuntos
Bacillus thuringiensis/genética , Proteínas de Bactérias/toxicidade , Endotoxinas/toxicidade , Hemípteros/efeitos dos fármacos , Proteínas Hemolisinas/toxicidade , Inseticidas/toxicidade , Animais , Bacillus thuringiensis/química , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endotoxinas/genética , Endotoxinas/metabolismo , Hemípteros/fisiologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Inseticidas/metabolismo , Oryza/parasitologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/parasitologia
14.
Arch Insect Biochem Physiol ; 104(1): e21661, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32011765

RESUMO

Polycalin has been confirmed as a binding protein of the Cry toxins in a few Lepidoptera insects, but its function in the action mechanism of Cry1Ac and whether it is involved in resistance evolution are still unclear. In this study, Ligand blot and enzyme-linked immunosorbent assays showed that Helicoverpa armigera polycalin could specifically interact with Cry1Ac with a high affinity (Kd = 118.80 nM). Importantly, antisera blocking polycalin in H. armigera larvae decreased the toxicity of Cry1Ac by 31.84%. Furthermore, the relative gene and protein expressions were lower in Cry1Ac-resistant strain (LF60) than that in Cry1Ac-susceptible strain (LF). These findings indicated that H. armigera polycalin was a possible receptor of Cry1Ac and may be contributed to the resistance to Cry1Ac.


Assuntos
Inseticidas/farmacologia , Lipocalinas/metabolismo , Mariposas/efeitos dos fármacos , Mariposas/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Endotoxinas/metabolismo , Endotoxinas/farmacologia , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/farmacologia , Proteínas de Insetos , Resistência a Inseticidas/genética , Inseticidas/metabolismo , Mariposas/metabolismo
15.
Appl Environ Microbiol ; 86(6)2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-31924619

RESUMO

Acetamiprid, a chloronicotinyl neonicotinoid insecticide, is among the most commonly used insecticides worldwide, and its environmental fate has caused considerable concern. The compound 1-(6-chloropyridin-3-yl)-N-methylmethanamine (IM 1-4) has been reported to be the main intermediate during acetamiprid catabolism in microorganisms, honeybees, and spinach. However, the molecular mechanism underlying the hydrolysis of acetamiprid to IM 1-4 has not yet been elucidated. In this study, a novel amidase (AceAB) that initially hydrolyzes the C-N bond of acetamiprid to generate IM 1-4 was purified and characterized from the acetamiprid-degrading strain Pigmentiphaga sp. strain D-2. Based on peptide profiling of the purified AceAB and the draft genome sequence of strain D-2, aceA (372 bp) and aceB (2,295 bp), encoding the α and ß subunits of AceAB, respectively, were cloned and found to be necessary for acetamiprid hydrolysis in strain D-2. The characteristics of AceAB were also systematically investigated. Though AceA and AceB showed 35% to 56% identity to the α and ß subunits of the N,N-dimethylformamidase from Paracoccus aminophilus, AceAB was specific for the hydrolysis of acetamiprid and showed no activities to N,N-dimethylformamide or its structural analogs.IMPORTANCE Acetamiprid, among the top neonicotinoid insecticides used worldwide, is one of the most important commercial insecticides. Due to its extensive use, the environmental fate of acetamiprid, especially its microbial degradation, has caused considerable concern. Although the catabolic pathways of acetamiprid in microorganisms have been extensively studied, the molecular mechanisms underlying acetamiprid biodegradation (except for a nitrile hydratase) remain largely unknown, and the enzyme responsible for the biotransformation of acetamiprid into its main intermediate, IM 1-4, have not yet been elucidated. The amidase AceAB and its encoding genes, aceA and aceB, characterized in this study, were found to be necessary and specific for the initial hydrolysis of the C-N bond of acetamiprid to generate IM 1-4 in Pigmentiphaga sp. strain D-2. The finding of the novel amidase AceAB will greatly enhance our understanding of the microbial catabolism of the widely used insecticide acetamiprid at the molecular level.


Assuntos
Alcaligenaceae/metabolismo , Amidoidrolases/metabolismo , Proteínas de Bactérias/metabolismo , Inseticidas/metabolismo , Neonicotinoides/metabolismo , Hidrólise
16.
J Agric Food Chem ; 68(6): 1588-1595, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31994388

RESUMO

The discovery of new, safe, and effective pesticides is one of the main means for modern crop protection and parasitic disease control. During the search for new insecticidal secondary metabolites from endophytes in Stemona sessilifolia (a traditional Chinese medicine with a long history as an insecticide), 10 new insecticidal endostemonines A-J (1-10) were identified from an endophytic Streptomyces sp. BS-1. Their structures were determined by comprehensive spectroscopic analysis. Endostemonines A-J represent the first reported naturally occurring pyrrole-2-carboxylic ester derivatives, which consisted of different fatty acid chains at the C-2 of pyrrole ring were produced by traditional Chinese medicine endophytic microbes. All new tested compounds exhibited strong lethal activity against Aphis gossypii (LC50 value range of 3.55-32.00 mg/L after 72 h). This research highlighted the discovery of pesticide natural products from insecticidal medicinal plant endophytes for the first time, paving a new pathway for the development of pest control.


Assuntos
Endófitos/química , Compostos Heterocíclicos com 3 Anéis/metabolismo , Inseticidas/metabolismo , Stemonaceae/microbiologia , Streptomyces/química , Streptomyces/metabolismo , Animais , Afídeos/efeitos dos fármacos , Endófitos/metabolismo , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/toxicidade , Inseticidas/química , Inseticidas/toxicidade , Metabolismo Secundário
17.
Artigo em Inglês | MEDLINE | ID: mdl-31899308

RESUMO

Glutathione S-transferases (GSTs) are a multifunctional protein superfamily that can catalyze the detoxification processes in an organism. In the present study, we determined the structure and function of GSTs in Chinese mitten crab (Eriocheir sinensis) by gene cloning, expression, and enzyme activity in order to investigate the metabolic detoxification of GSTs in the hepatopancreas and muscles under three pesticide (trichlorfon, ß-cypermethrin and avermectin) stresses. Multiple sequence alignment analysis showed that all the three Es-GST genes possessed N-terminal, and C-terminal domain as well as G-binding sites, while Es-GST2 and Es-GST3 contained Mu-type GST-specific Mu-loop structures. Phylogenetic tree analysis revealed that the three Es-GSTs belonged to the Mu-type GST of crustaceans. The quantitative real-time PCR revealed that the three Es-GSTS were expressed in 9 tissues of Eriocheir sinensis, with highest expression in hepatopancreas and muscle. The expression of the three Es-GSTS significantly increased in the hepatopancreas and muscle under the three pesticide stresses compared to the control group, and a steady increase in GST activity was observed. The study showed that the three Es-GSTs belong to the Mu-type GST of the crustaceans and might play an important role in the metabolic detoxification in Eriocheir sinensis.


Assuntos
Braquiúros/enzimologia , Glutationa Transferase , Hepatopâncreas/metabolismo , Inseticidas , Músculos/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Expressão Gênica , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Inativação Metabólica , Inseticidas/metabolismo , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Ivermectina/metabolismo , Ivermectina/toxicidade , Piretrinas/metabolismo , Piretrinas/toxicidade , Triclorfon/metabolismo , Triclorfon/toxicidade
18.
Chemosphere ; 246: 125759, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31891844

RESUMO

It is well known that microorganisms can reduce the effectiveness of organophosphate pesticides after their application. But, little information is available concerning the effect of rice endophytic bacteria on the degradation of diazinon, an organophosphate pesticide used in control of the rice stem-borer, absorbed by the rice plant. Thus, aim of this study was to characterize the endophytic bacterial isolates, isolated from diazinon-treated and non-treated rice plants in paddy fields, in terms of diazinon degradation and to investigate whether potent isolates that degrade diazinon in vitro might have the same effect in the rice plant. The results showed that all endophytic isolates, isolated from both groups of rice plants (diazinon-treated and non-treated rice plants), could grow in mineral salt medium (MSM) supplemented with diazinon (20 mg L-1) as a sole carbon source, and 3.79-58.52% of the initial dose of the insecticide was degraded by the isolates within 14 d of incubation. Phylogenetic analysis based on 16 S rRNA sequencing indicated that the potent isolates (DB26-R and B6-L) clearly belonged to the Bacillus genus. The diazinon concentrations in rice plants co-inoculated with B. altitudinis DB26-R and B. subtilis subsp. Inaquosorum B6-L and single-inoculated with these strains were reduced significantly compared with endophyte-free rice plants. These results provide unequivocal evidence that the rice endophytic bacteria, in addition to in vitro degradation of diazinon, are also involved in the rapid inactivation of diazinon in rice plants treated with diazinon (in vivo degradation of diazinon).


Assuntos
Diazinon/metabolismo , Endófitos/metabolismo , Inseticidas/metabolismo , Oryza/microbiologia , Animais , Biodegradação Ambiental , Diazinon/análise , Inseticidas/análise , Oryza/metabolismo , Filogenia
19.
J Agric Food Chem ; 68(7): 1966-1973, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986037

RESUMO

Pesticide pollution of surface water represents a considerable risk for algae and thus affects the structure and stability of aquatic ecosystems. To investigate the risk of flufiprole to phytoplankton, the digestion and uptake of flufiprole as well as the toxic effects of flufiprole enantiomers and the six metabolites to Chlorella pyrenoidosa were investigated. Flufiprole enantiomers were mainly metabolized to flufiprole amide and detrifluoromethylsulfinyl flufiprole in culture medium, while various metabolites were formed in algae, notably the amide derivative and fipronil. Chlorella pyrenoidosa showed a strong absorption capacity for the flufiprole series. The EC50 values (96 h) indicated that fipronil was the most toxic compound, approximately 5 times as toxic as rac-flufiprole. R-flufiprole was more toxic than S-flufiprole. The contents of chlorophylls, malondialdehyde (MDA), reactive oxygen species (ROS), and total antioxidant capacity (T-AOC) were significantly altered by the chemicals in most cases, especially fipronil. Our results supported the potential detrimental effect of the metabolites of flufiprole on algae.


Assuntos
Chlorella/metabolismo , Inseticidas/metabolismo , Inseticidas/toxicidade , Pirazóis/metabolismo , Pirazóis/toxicidade , Biodegradação Ambiental , Biotransformação , Chlorella/efeitos dos fármacos , Clorofila/metabolismo , Inseticidas/química , Cinética , Malondialdeído/metabolismo , Pirazóis/química , Espécies Reativas de Oxigênio/metabolismo , Estereoisomerismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
20.
Chemosphere ; 244: 125507, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31835049

RESUMO

Agricultural and household applications of pyrethroid insecticides have significantly increased residual concentrations in living cells and environments. The enhanced concentration is toxic for living beings. Pyrethroid hydrolase enzyme (pyrethroid catalyzing esterase) regulates pyrethroid degradation, and has been well reported in various organisms (bacteria, fungi, insects and animals). Hydrolysis mechanisms of these esterases are different from others and properly function at factors viz., optimum temperature, pH and physicochemical environment. Active site of the enzyme contains common amino acids that play important role in pyrethroid catalysis. Immobilization technology emphasizes the development of better reusable efficiency of pyrethroid hydrolases to carry out large-scale applications for complete degradation of pyrethroids from the environments. In this review we have attempted to provide insights of pyrethroid-degrading esterases in different living systems along with complete mechanisms.


Assuntos
Biodegradação Ambiental , Esterases/metabolismo , Inseticidas/metabolismo , Piretrinas/metabolismo , Animais , Hidrolases , Hidrólise , Insetos , Inseticidas/análise , Piretrinas/análise , Temperatura
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