RESUMEN

Imidacloprid (IDP) is an active ingredient of the Admire brand pesticide used to control the vector (Asian citrus psyllid) that transmits the causative organism Candidatus Liberibacter asiaticus (CLas) for citrus greening or huanglongbing disease. Imidacloprid products are applied via soil drench where citrus roots are mostly concentrated which is between 0 and 60 cm depth. These soil depths exhibit different characteristics that may affect IDP leaching beyond the rooting zone. Representative soil samples were collected from Entisols and Ultisols, which are the dominant soil orders under citrus production in central Florida, at 15 cm increments up to 60 cm to estimate and understand the batch sorption, kinetics, equilibria, and degradation of IDP. Results showed that the equilibrium time for IDP at 0-15 cm depth (10 hours) was 2 times faster than at 15-60 cm (20 hours) for the Entisol. Nevertheless, all depths reached equilibrium within 24 hours for the Entisol. The 0-30 cm depth adsorbed 2 times more IDP than the 30-60 cm depth for both soils. Nevertheless, the adsorption coefficient was approximately ≤ 1 mL g-1 for both soils. The half-life of IDP in both soils ranged from 10 to 17 days. The Entisol showed higher adsorption than the Ultisol at both depths, probably due to relatively lower organic carbon (OC) content in the Ultisol compared to the Entisol. Thus, the Ultisol showed high IDP leaching vulnerability compared to the Entisol. Movement of IDP is affected by the amount of OC in the citrus critical zone.

Asunto(s)

Citrus , Neonicotinoides , Nitrocompuestos , Contaminantes del Suelo , Suelo , Neonicotinoides/química , Neonicotinoides/metabolismo , Nitrocompuestos/química , Nitrocompuestos/metabolismo , Florida , Suelo/química , Adsorción , Contaminantes del Suelo/química , Contaminantes del Suelo/metabolismo , Citrus/química , Cinética , Semivida , Insecticidas/química , Insecticidas/metabolismo , Imidazoles/química , Imidazoles/metabolismo

RESUMEN

Cordyceps javanica has been registered as a fungal insecticide in several countries. However, little is known about whether metabolic toxins are involved in the insecticidal process. In this research, we assessed the insecticidal activity of the fermentation broth of C. javanica. Myzus persicae mortality differed when exposed to the metabolized C. javanica broths at 3 days post fermentation (DPF) and 5 DPF. Comparison of the metabolic fluid at 3 DPF and 5 DPF revealed a key alkaloid, heteratisine, which was found to have insecticidal activity and acetylcholinesterase (AChE) inhibitory activity. Heteratisine has high insecticidal activity against adult M. persicae, the absolute 50% lethal concentration (LC50) was only 0.2272 mg/L. Heteratisine showed high inhibitory activity on AChE with the 50% maximal inhibitory concentration (IC50) of 76.69 µM. Molecular docking and dynamic simulations showed that heteratisine conjugation occurs at the peripheral anionic site (PAS) of the AChE of M. persicae, leading to suppression of enzyme activity. Heteratisine was rarely found in fungal metabolites, which helps us to understand the complex and elaborate insecticidal mechanism of C. javanica.

Asunto(s)

Acetilcolinesterasa , Áfidos , Inhibidores de la Colinesterasa , Cordyceps , Insecticidas , Simulación del Acoplamiento Molecular , Cordyceps/metabolismo , Insecticidas/química , Insecticidas/farmacología , Insecticidas/metabolismo , Insecticidas/toxicidad , Animales , Áfidos/efectos de los fármacos , Inhibidores de la Colinesterasa/farmacología , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/metabolismo , Inhibidores de la Colinesterasa/toxicidad , Acetilcolinesterasa/metabolismo , Alcaloides/química , Metabolismo Secundario

RESUMEN

Synthetic pyrethroids are widely used insecticides which may cause chronic diseases in non-target organisms upon long-term exposure. Microbial degradation offers a reliable method to remove them from the environment. This study focused on Brevibacillus parabrevis BCP-09 and its enzymes for degrading pyrethroids. The predicted deltamethrin-degrading genes phnA and mhpC were used to construct recombinant plasmids. These plasmids, introduced into Escherichia coli BL21(DE3) cells and induced with L-arabinose. The results indicated that the intracellular crude enzyme efficiently degraded deltamethrin by 98.8 %, ß-cypermethrin by 94.84 %, and cyfluthrin by 73.52 % within 24 h. The hydrolytic enzyme MhpC possesses a catalytic triad Ser/His/Asp and a typical "Gly-X-Ser-X-Gly" conservative sequence of the esterase family. Co-cultivation of induced E. coli PhnA and E. coli MhpC resulted in degradation rates of 41.44 ± 3.55 % and 60.30 ± 4.55 %, respectively, for deltamethrin after 7 d. This study states that the degrading enzymes from B. parabrevis BCP-09 are an effective method for the degradation of pyrethroids, providing available enzyme resources for food safety and environmental protection.

Asunto(s)

Brevibacillus , Nitrilos , Piretrinas , Piretrinas/metabolismo , Brevibacillus/metabolismo , Brevibacillus/genética , Nitrilos/metabolismo , Insecticidas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Hidrolasas/metabolismo , Hidrolasas/genética , Biodegradación Ambiental , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Plásmidos/genética

RESUMEN

Nitenpyram, taking the place of imidacloprid, is a widely used neonicotinoid insecticide to control Nilaparvata lugens in Asia. Two P450s, CYP4CE1 and CYP6ER1, are key factors in the metabolic resistance against nitenpyram and imidacloprid. In this study, we found that CYP4CE1 expression was strongly associated with nitenpyram resistance in 8 field-collected populations, whereas CYP6ER1 expression correlated with imidacloprid resistance. Hence, we focused on nitenpyram metabolism by CYP4CE1, due to that imidacloprid metabolism by CYP6ER1 has intensively investigated. Mass spectrometry analysis revealed that recombinant CYP4CE1 metabolized nitenpyram into three products, N-desmethyl nitenpyram, hydroxy-nitenpyram, and N-desmethyl hydroxy-nitenpyram, with a preference for hydroxylation. In contrast, CYP6ER1 metabolized nitenpyram into a single product, N-desmethyl nitenpyram. These results provide new insights into the specific catalytic mechanisms of P450 enzymes in neonicotinoid metabolism and underscore the importance of different catalytic reactions in neonicotinoid insecticide resistance.

Asunto(s)

Proteínas de Insectos , Insecticidas , Neonicotinoides , Oxidación-Reducción , Neonicotinoides/metabolismo , Neonicotinoides/química , Insecticidas/metabolismo , Insecticidas/química , Hidroxilación , Animales , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/química , Desmetilación , Hemípteros/metabolismo , Hemípteros/genética , Hemípteros/enzimología , Nitrocompuestos/metabolismo , Nitrocompuestos/química , Sistema Enzimático del Citocromo P-450/metabolismo , Sistema Enzimático del Citocromo P-450/genética , Resistencia a los Insecticidas/genética

RESUMEN

The green peach aphid, Myzus persicae, is a worldwide agricultural pest. Chlorpyrifos has been widely used to control M. persicae for decades, thus leading to a high resistance to chlorpyrifos. Recent studies have found that insect odorant binding proteins (OBPs) play essential roles in insecticide resistance. However, the potential resistance mechanism underlying the cross-link between aphid OBPs and chlorpyrifos remains unclear. In this study, two OBPs (MperOBP3 and MperOBP7) were found overexpressed in M. persicae chlorpyrifos-resistant strains (CRR) compared to chlorpyrifos-sensitive strains (CSS); furthermore, chlorpyrifos can significantly induce the expression of both OBPs. An in vitro binding assay indicated that both OBPs strongly bind with chlorpyrifos; an in vivo RNAi and toxicity bioassay confirmed silencing either of the two OBPs can increase the susceptibility of aphids to chlorpyrifos, suggesting that overexpression of MperOBP3 and MperOBP7 contributes to the development of resistance of M. persicae to chlorpyrifos. Our findings provide novel insights into insect OBPs-mediated resistance mechanisms.

Asunto(s)

Áfidos , Cloropirifos , Proteínas de Insectos , Resistencia a los Insecticidas , Insecticidas , Receptores Odorantes , Animales , Áfidos/genética , Áfidos/efectos de los fármacos , Áfidos/metabolismo , Cloropirifos/metabolismo , Cloropirifos/farmacología , Receptores Odorantes/genética , Receptores Odorantes/metabolismo , Receptores Odorantes/química , Resistencia a los Insecticidas/genética , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , Insecticidas/farmacología , Insecticidas/metabolismo , Prunus persica/genética , Prunus persica/parasitología , Prunus persica/metabolismo , Prunus persica/química

RESUMEN

Spodoptera litura is a significant agricultural pest, and its glutathione S-transferase (GST) plays a crucial role in insecticide resistance. This study aimed to investigate the relationship between the SlGSTe11 gene of S. litura and resistance to cyantraniliprole and nicotine. Transcriptome analysis revealed that SlGSTe11 is highly expressed mainly in fat bodies, with a significant increase in SlGSTe11 gene expression under induction by cyantraniliprole and nicotine. The ectopic expression of the SlGSTe11 gene in transgenic fruit flies resulted in a 5.22-fold increase in the tolerance to cyantraniliprole. Moreover, compared to the UAS-SlGSTe11 line, the Act5C-UAS>SlGSTe11 line laid more eggs and had a lower mortality after nicotine exposure. RNAi-mediated inhibition of SlGSTe11 gene expression led to a significant increase in the mortality of S. litura under cyantraniliprole exposure. In vitro metabolism experiments demonstrated that the recombinant SlGSTe11 protein efficiently metabolizes cyantraniliprole. Molecular docking results indicated that SlGSTe11 has a strong affinity for both cyantraniliprole and nicotine. These findings suggest that SlGSTe11 is involved in the development of resistance to cyantraniliprole and nicotine in S. litura.

Asunto(s)

Cuerpo Adiposo , Glutatión Transferasa , Proteínas de Insectos , Resistencia a los Insecticidas , Insecticidas , Nicotina , Pirazoles , Spodoptera , ortoaminobenzoatos , Animales , Spodoptera/genética , Spodoptera/efectos de los fármacos , Spodoptera/metabolismo , Spodoptera/enzimología , Spodoptera/crecimiento & desarrollo , Insecticidas/farmacología , Insecticidas/metabolismo , Insecticidas/química , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/química , ortoaminobenzoatos/metabolismo , ortoaminobenzoatos/farmacología , Pirazoles/farmacología , Nicotina/metabolismo , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Glutatión Transferasa/química , Resistencia a los Insecticidas/genética , Cuerpo Adiposo/metabolismo , Cuerpo Adiposo/enzimología , Cuerpo Adiposo/efectos de los fármacos , Simulación del Acoplamiento Molecular

RESUMEN

The versatility of cytochrome P450 reductase (CPR) in transferring electrons to P450s from other closely related species has been extensively exploited, e.g., by using An. gambiae CPR (AgCPR), as a homologous surrogate, to validate the role of An. funestus P450s in insecticide resistance. However, genomic variation between the AgCPR and An. funestus CPR (AfCPR) suggests that the full metabolism spectrum of An. funestus P450s might be missed when using AgCPR. To test this hypothesis, we expressed AgCPR and AfCPR side-by-side with CYP6P9a and CYP6P9b and functionally validated their role in the detoxification of insecticides from five different classes. Major variations were observed within the FAD- and NADP-binding domains of AgCPR and AfCPR, e.g., the coordinates of the second FAD stacking residue AfCPR-Y456 differ from that of AgCPR-His456. While no significant differences were observed in the cytochrome c reductase activities, when co-expressed with their endogenous AfCPR, the P450s significantly metabolized higher amounts of permethrin and deltamethrin, with CYP6P9b-AfCPR membrane metabolizing α-cypermethrin as well. Only the CYP6P9a-AfCPR membrane significantly metabolized DDT (producing dicofol), bendiocarb, clothianidin, and chlorfenapyr (bioactivation into tralopyril). This demonstrates the broad substrate specificity of An. funestus CYP6P9a/-b, capturing their role in conferring cross-resistance towards unrelated insecticide classes, which can complicate resistance management.

Asunto(s)

Anopheles , Resistencia a los Insecticidas , Insecticidas , NADPH-Ferrihemoproteína Reductasa , Piretrinas , Anopheles/genética , Anopheles/efectos de los fármacos , Anopheles/enzimología , Anopheles/metabolismo , Animales , Resistencia a los Insecticidas/genética , NADPH-Ferrihemoproteína Reductasa/metabolismo , NADPH-Ferrihemoproteína Reductasa/genética , Insecticidas/farmacología , Insecticidas/metabolismo , Piretrinas/farmacología , Piretrinas/metabolismo , Oxidación-Reducción , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Sistema Enzimático del Citocromo P-450/metabolismo , Sistema Enzimático del Citocromo P-450/genética , Especificidad por Sustrato , Nitrilos/metabolismo , Nitrilos/farmacología , Permetrina/farmacología

RESUMEN

The mechanisms of insecticide resistance are complex. Recent studies have revealed a novel mechanism involving the chemosensory system in insecticide resistance. However, the specific binding mechanism between olfactory-related genes and insecticides needs to be clarified. In this study, the binding mechanism between pyrethroid insecticide deltamethrin and RpCSP6 from Rhopalosiphum padi was investigated by using computational and multiple experimental methods. RpCSP6 was expressed in different tissues and developmental stages of R. padi and can be induced by deltamethrin. Knockdown of RpCSP6 significantly increased the susceptibility of R. padi to deltamethrin. The binding affinity of RpCSP6 to 24 commonly used insecticides was measured. Seven key residues were found to steadily interact with deltamethrin, indicating their significance in the binding affinity to the insecticide. Our research provided insights for effectively analyzing the binding mechanism of insect CSPs with insecticides, facilitating the development of new and effective insecticides that target insect CSPs.

Asunto(s)

Proteínas de Insectos , Resistencia a los Insecticidas , Insecticidas , Nitrilos , Piretrinas , Piretrinas/metabolismo , Piretrinas/farmacología , Nitrilos/metabolismo , Nitrilos/farmacología , Nitrilos/química , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Insecticidas/farmacología , Insecticidas/metabolismo , Insecticidas/química , Resistencia a los Insecticidas/genética , Animales , Unión Proteica

RESUMEN

Host-symbiont interaction plays a crucial role in determining the host's fitness under toxic stress, as observed in numerous insect species. However, the mechanism of the symbionts involved in the detoxification of insecticides remains poorly known. In this study, through microbiome, proteomic, and genomic analysis, we identified a prevalent symbiont, Enterococcus casseliflavus EMBL-3, in a major invasive insect pest,Spodoptera frugiperda. This symbiont enhances the host's insecticide resistance to chlorantraniliprole by breaking amide bonds and dehalogenating insecticides. Complying with the increase in exposure risk of chlorantraniliprole, the E. casseliflavus isolates of insects' symbionts but not those from mammals or environmental strains showed a significant enrichment of potential chlorantraniliprole degradation genes. EMBL-3 is popular in field population insects with efficient horizontal transmission ability through cross-diet and cannibalism. This study provides a new therapeutic target for agricultural pests based on symbiont-targeted insect control for global crop protection.

Asunto(s)

Enterococcus , Insecticidas , Spodoptera , Simbiosis , ortoaminobenzoatos , Animales , Insecticidas/metabolismo , Insecticidas/farmacología , Insecticidas/química , Spodoptera/microbiología , Spodoptera/efectos de los fármacos , Enterococcus/metabolismo , Enterococcus/genética , Enterococcus/efectos de los fármacos , ortoaminobenzoatos/metabolismo , ortoaminobenzoatos/farmacología , Inactivación Metabólica , Resistencia a los Insecticidas , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética

RESUMEN

Pyrethrins are natural insecticides biosynthesised by Asteraceae plants, such as Tanacetum cinerariifolium and have a long history, dating back to ancient times. Pyrethrins are often used as low-persistence and safe insecticides to control household, horticultural, and agricultural insect pests. Despite its long history of use, pyrethrin biosynthesis remains a mystery, presenting a significant opportunity to improve yields and meet the growing demand for organic agriculture. To achieve this, both genetic modification and non-genetic methods, such as chemical activation and priming, are indispensable. Plants use pyrethrins as a defence against herbivores, but pyrethrin biosynthesis pathways are shared with plant hormones and signal molecules. Hence, the insight that pyrethrins may play broader roles than those traditionally expected is invaluable to advance the basic and applied sciences of pyrethrins.

Asunto(s)

Insecticidas , Piretrinas , Piretrinas/metabolismo , Insecticidas/metabolismo , Chrysanthemum cinerariifolium/metabolismo , Plaguicidas/metabolismo , Animales , Vías Biosintéticas

RESUMEN

Cyromazine, a triazine insecticide, raises food safety concerns due to residues in vegetables like cowpeas. Microbial metabolism is key for pesticide elimination, but bacteria efficient in cyromazine degradation are limited, with uncharacterized enzymes. This study isolated a highly efficient cyromazine-degrading bacterium, Mycobacterium sp. M15, from a cowpea field. M15 utilized cyromazine as the sole carbon source for its growth and completely degraded 0.5 mM cyromazine within 24 h. The degradation pathway involved hydrolyzing cyromazine to N-cyclopropylammeline and further to N-cyclopropylammelide, with amino groups removed sequentially. The cyclopropylamine group in N-cyclopropionamide continued to hydrolyze to cyanuric acid. A protein, CriA, identified as an aminohydrolase in M15, degraded cyromazine to N-cyclopropylammeline. Using CriA reduced cyromazine residues on cowpea surfaces and completely degraded them in immersion solutions. These findings offer insights into cyromazine's microbial degradation mechanism and highlight the potential of cyromazine-degrading enzymes in enhancing food safety.

Asunto(s)

Proteínas Bacterianas , Biodegradación Ambiental , Mycobacterium , Triazinas , Vigna , Triazinas/metabolismo , Triazinas/química , Vigna/metabolismo , Vigna/química , Mycobacterium/metabolismo , Mycobacterium/enzimología , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Insecticidas/metabolismo , Insecticidas/química

RESUMEN

Pesticides employed for controlling domestic and agricultural pests are among the most dangerous environmental contaminants. Nevertheless, negligent usage and a lack of technical expertise have led to the contamination and pollution of various ecological niches. The extensive utilization of the organophosphate chlorpyrifos (CPs) for insect infestation control, coupled with its detrimental effects and persistence in the ecosystem, has led to calls for its removal from contaminated sites. The study is mainly focused on degradation of CPs; using viz. Bacillus wiedmannii A3 and Bacillus cereus P14 isolated from tea rhizosphere soil having pesticide contamination in Sonitpur district, Assam, India. These two bacterial strains were able to degrade CPs in vitro within 3 days. Reverse-phase HPLC analysis suggested about 96% reduction of CPs concentration upon bacterial treatment. Again, in case of A3, GC-MS analysis revealed that CPs was modified to 2-hydroxy-3,5,6-trichloropyridine and chlorpyrifos-oxon, thus finally metabolized into non-toxic products. While analyzing P14, silane, dimethyl (2,2,2-trichloroethoxy) propoxy, and 3-aminobenzoic acid, N-trimethylsilyl-, trimethylsilyl ester were identified. These compounds were subsequently transformed into non-toxic products. In addition to this, they demonstrated a significant boost of plant growth-promoting traits in both absence and presence of CPs; also showed growth development in nursery scale condition. Moreover, they functioned as biocontrol agents against Phellinus lamaensis and Colletotrichum gloeosporioides, responsible for brown root rot and anthracnose in North East India tea plantations, respectively. Thus, the pesticide-tolerant Bacilli strains A3 and P14 could be used as bioremediation of contaminated sites and also as biostimulants, and biocontrols in tea crop production.

Asunto(s)

Bacillus , Biodegradación Ambiental , Cloropirifos , Microbiología del Suelo , Cloropirifos/metabolismo , Bacillus/metabolismo , Bacillus/aislamiento & purificación , India , Rizosfera , Camellia sinensis/microbiología , Camellia sinensis/crecimiento & desarrollo , Contaminantes del Suelo/metabolismo , Insecticidas/metabolismo , Insecticidas/farmacología , Té/microbiología , Té/química

RESUMEN

As a member of the neonicotinoid group, imidaclothiz has garnered increasing attention due to its possible health risks. This study investigated the metabolism and distribution of imidaclothiz in mice. Seven imidaclothiz metabolites were found, four of which are known, and three are unknown. The metabolic reactions observed were hydroxylation, nitrate ester hydrolysis, methylation, urea formation, and reduction to NO. Precise quantification revealed that after 2 h of oral administration, imidaclothiz rapidly dispersed into various organs and tissues, peaking at 4 h, and was then swiftly eliminated. No propensity for accumulation in the body, particularly in the liver, was observed. Toxicity data from the T.E.S.T prediction indicated that imidaclothiz had moderate toxicity to rats, and a majority of its metabolites were more toxic than the parent compound. These findings complement the existing knowledge of the imidaclothiz environmental fate in mammals and offer a reference point for its application in agriculture and industry.

Asunto(s)

Insecticidas , Neonicotinoides , Animales , Ratones , Insecticidas/metabolismo , Neonicotinoides/metabolismo , Masculino , Hígado/metabolismo , Hígado/efectos de los fármacos , Ratas , Femenino

RESUMEN

The enzyme glutamate-cysteine ligase catalytic subunit (Gclc) is a rate-limiting enzyme in the biosynthesis of glutathione that is involved in antioxidant defense, detoxification of xenobiotics, and/or its metabolites and regulates the cell cycle and immune function. Therefore, Gclc presents an appealing target for the development of novel insecticides. In this study, we conducted high-throughput virtual screening from the ZINC20 database and identified three compounds with high binding affinity to the Tribolium castaneum Gclc (TcGclc). Ultimately, we selected ZINC000032992384 due to its superior stability and lowest binding energy, as determined through molecular dynamics simulations. Bioassay results revealed that the IC50 value of ZINC000032992384 was 19.70 µM lower than that of BSO (49.67 µM). Furthermore, the larval mortality in the ZINC000032992384 treated group was 63.8%, significantly higher than that of the controls (29.1% in the dichlorvos group and 6.4% in the acetone group). This study provides novel insights for the development of a Gclc-targeted inhibitor as a potent insecticide based on the interaction between receptors and ligands.

Asunto(s)

Dominio Catalítico , Inhibidores Enzimáticos , Glutamato-Cisteína Ligasa , Proteínas de Insectos , Insecticidas , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Tribolium , Animales , Tribolium/enzimología , Tribolium/química , Insecticidas/química , Insecticidas/farmacología , Insecticidas/metabolismo , Proteínas de Insectos/química , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Glutamato-Cisteína Ligasa/metabolismo , Glutamato-Cisteína Ligasa/genética , Glutamato-Cisteína Ligasa/química , Bioensayo , Larva/efectos de los fármacos , Larva/crecimiento & desarrollo , Ensayos Analíticos de Alto Rendimiento

RESUMEN

Fipronil, a phenylpyrazole insecticide, is used to kill insects resistant to conventional insecticides. Though its regular and widespread use has substantially reduced agricultural losses, it has also caused its accumulation in various environmental niches. The biodegradation is an effective natural process that helps in reducing the amount of residual insecticides. This study deals with an in-depth investigation of fipronil degradation kinetics and pathways in Pseudomonas sp. FIP_A4 using multi-omics approaches. Soil-microcosm results revealed ∼87% degradation within 40 days. The whole genome of strain FIP_A4 comprises 4.09 Mbp with 64.6% GC content. Cytochrome P450 monooxygenase and enoyl-CoA hydratase-related protein, having 30% identity with dehalogenase detected in the genome, can mediate the initial degradation process. Proteome analysis revealed differential enzyme expression of dioxygenases, decarboxylase, and hydratase responsible for subsequent degradation. Metabolome analysis displayed fipronil metabolites in the presence of the bacterium, supporting the proposed degradation pathway. Molecular docking and dynamic simulation of each identified enzyme in complex with the specific metabolite disclosed adequate binding and high stability in the enzyme-metabolite complex. This study provides in-depth insight into genes and their encoded enzymes involved in the fipronil degradation and formation of different metabolites during pollutant degradation. The outcome of this study can contribute immensely to developing efficient technologies for the bioremediation of fipronil-contaminated soils.

Asunto(s)

Biodegradación Ambiental , Insecticidas , Pseudomonas , Pirazoles , Microbiología del Suelo , Contaminantes del Suelo , Pirazoles/metabolismo , Pseudomonas/metabolismo , Pseudomonas/genética , Insecticidas/metabolismo , Contaminantes del Suelo/metabolismo , Simulación del Acoplamiento Molecular , Suelo/química , Sistema Enzimático del Citocromo P-450/metabolismo

RESUMEN

Bifenthrin (BF) is a broad-spectrum type I pyrethroid insecticide that acts on insects by impairing the nervous system and inhibiting ATPase activity, and it has toxic effects on non-target organisms and high persistence in the environment. This study aimed to determine the potential of six different fungi, including Pseudozyma hubeiensis PA, Trichoderma reesei PF, Trichoderma koningiopsis PD, Purpureocillium lilacinum ACE3, Talaromyces pinophilus ACE4, and Aspergillus niger AJ-F3, to degrade BF. Three different concentrations of BF, including 0.1%, 0.2%, and 0.3% w/v, were used in the sensitivity testing that revealed a significant (p ≤ 0.01) impact of BF on fungal growth. Enzymatic assays demonstrated that both intracellular and extracellular carboxylesterases hydrolyzed BF with the enzymatic activity of up to 175 ± 3 U (µmol/min) and 45 ± 1 U, respectively. All tested fungi were capable of utilizing BF as a sole carbon source producing 0.06 ± 0.01 to 0.45 ± 0.01 mg dry biomass per mg BF. Moreover, the presence of PytH was determined in the fungi using bioinformatics tools and was found in A. niger, T. pinophilus, T. reesei, and P. lilacinum. 3D structures of the PytH homologs were predicted using AlphaFold2, and their intermolecular interactions with pyrethroids were determined using MOE. All the homologs interacted with different pyrethroids with a binding energy of lesser than - 10 kcal/mol. Based on the study, it was concluded that the investigated fungi have a greater potential for the biodegradation of BF.

Asunto(s)

Biodegradación Ambiental , Insecticidas , Piretrinas , Piretrinas/metabolismo , Insecticidas/metabolismo , Insecticidas/química , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Carbono/metabolismo , Carbono/química , Carboxilesterasa/metabolismo , Hongos/enzimología , Simulación por Computador

RESUMEN

Clothianidin, classified as a second-generation neonicotinoid, has achieved extensive application due to its high efficacy against insect pests. This broad-spectrum usage has resulted in its frequent detection in environmental surveys. CYP2C19 and CYP3A4 are crucial for converting clothianidin to desmethyl-clothianidin (dm-clothianidin). The expression of these CYP450s can be significantly influenced by genetic polymorphisms. The objective of our research was to examine the catalytic effects of 27 CYP3A4 variants and 31 CYP2C19 variants on the metabolism of clothianidin within recombinant insect microsomes. These variants were assessed through a well-established incubation procedure. In addition, the concentration of its metabolite dm-clothianidin was quantified by employing an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Lastly, the kinetic parameters of these CYP3A4 and CYP2C19 variants were calculated by applying Michaelis-Menten kinetic analysis to fit the data. The observed changes in enzyme activity were related to the metabolic transformation of clothianidin to dm-clothianidin. In the CYP2C19 metabolic pathway, one variant (CYP2C19.23) showed no notable change in intrinsic clearance (CLint), four variants (CYP2C19.29, .30, .31 and L16F) demonstrated a marked increase in CLint (110.86-183.46 %), and the remaining 25 variants exhibited a considerable decrease in CLint (26.38-89.79 %), with a maximum decrease of 73.62 % (CYP2C19.6). In the CYP3A4 metabolic pathway, 26 variants demonstrated significantly reduced CLint (10.54-52.52 %), with a maximum decrease of 89.46 % (CYP3A4.20). Our results suggested that most variants of CYP3A4 and CYP2C19 significantly altered the enzymatic activities associated with clothianidin metabolism to various degrees. This study provides new insights into assessing the metabolic behavior of pesticides and delivers crucial data that can guide clinical detoxification strategies.

Asunto(s)

Citocromo P-450 CYP2C19 , Citocromo P-450 CYP3A , Guanidinas , Neonicotinoides , Polimorfismo Genético , Tiazoles , Citocromo P-450 CYP2C19/genética , Citocromo P-450 CYP2C19/metabolismo , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Tiazoles/metabolismo , Guanidinas/metabolismo , Neonicotinoides/metabolismo , Humanos , Animales , Cinética , Espectrometría de Masas en Tándem , Insecticidas/metabolismo , Microsomas/metabolismo

RESUMEN

BACKGROUND: Natural products are important sources for the discovery of new biopesticides to control the worldwide destructive pests Acyrthosiphon pisum Harris. Here, insecticidal substances were discovered and characterized from the secondary metabolites of the bio-control microorganism Bacillus velezensis strain ZLP-101, as informed by whole-genome sequencing and analysis. RESULTS: The genome was annotated, revealing the presence of four potentially novel gene clusters and eight known secondary metabolite synthetic gene clusters. Crude extracts, prepared through ammonium sulfate precipitation, were used to evaluate the effects of strain ZLP-101 on Acyrthosiphon pisum Harris aphid pests via exposure experiments. The half lethal concentration (LC50) of the crude extract from strain ZLP-101 against aphids was 411.535 mg/L. Preliminary exploration of the insecticidal mechanism revealed that the crude extract affected aphids to a greater extent through gastric poisoning than through contact. Further, the extracts affected enzymatic activities, causing holes to form in internal organs along with deformation, such that normal physiological activities could not be maintained, eventually leading to death. Isolation and purification of extracellular secondary metabolites were conducted in combination with mass spectrometry analysis to further identify the insecticidal components of the crude extracts. A total of 15 insecticidal active compounds were identified including iturins, fengycins, surfactins, and spergualins. Further insecticidal experimentation revealed that surfactin, iturin, and fengycin all exhibited certain aphidicidal activities, and the three exerted synergistic lethal effects. CONCLUSIONS: This study improved the available genomic resources for B. velezensis and serves as a foundation for comprehensive studies of the insecticidal mechanism by Bacillus velezensis ZLP-101 in addition to the active components within biological control strains.

Asunto(s)

Áfidos , Bacillus , Insecticidas , Lipopéptidos , Animales , Áfidos/efectos de los fármacos , Bacillus/genética , Bacillus/metabolismo , Lipopéptidos/farmacología , Lipopéptidos/química , Lipopéptidos/metabolismo , Lipopéptidos/aislamiento & purificación , Insecticidas/farmacología , Insecticidas/metabolismo , Insecticidas/química , Familia de Multigenes , Metabolismo Secundario , Control Biológico de Vectores , Secuenciación Completa del Genoma , Genoma Bacteriano/genética

RESUMEN

Thiacloprid, a neonicotinoid insecticide, has become one of the major control agents for the pine sawyer beetle, Monochamus alternatus Hope, however, the mechanism of detoxification is unknown. We demonstrate that glutathione S-transferases (GSTs) and nicotinic acetylcholine receptors (nAChRs) are involved in the rapid detoxification of thiacloprid in M. alternatus larvae. The activity of detoxification enzyme GSTs was significantly higher, while the activity of acetylcholinesterase (AChE) was inhibited under thiacloprid exposure. The inhibition of AChE activity led to lethal over-stimulation of the cholinergic synapse, which was then released by the rapid downregulation of nAChRs. Meanwhile, GSTs were overexpressed to detoxify thiacloprid accordingly. A total of 3 nAChR and 12 GST genes were identified from M. alternatus, among which ManAChRα2 and MaGSTs1 were predicted to confer thiacloprid tolerance. RNA interference (RNAi) was subsequently conducted to confirm the function of ManAChRα2 and MaGSTs1 genes in thiacloprid detoxification. The successful knock-down of the ManAChRα2 gene led to lower mortality of M. alternatus under LC30 thiacloprid treatment, and the suppression of the MaGSTs1 gene increased the mortality rate of M. alternatus. However, the mortality rate has no significant difference with controls when thiacloprid was fed together with both dsMaGSTs1 and dsManAChRα2. Molecular docking modeled the molecular basis for interaction between MaGSTs1/ManAChR and thiacloprid. This study highlights the important roles that ManAChRα2 and MaGSTs1 genes play in thiacloprid detoxification through transcriptional regulation and enzymatic metabolization, and proposes a new avenue for integrated pest management that combines pesticides and RNAi technology as an efficient strategy for M. alternatus control.

Asunto(s)

Escarabajos , Glutatión Transferasa , Insecticidas , Neonicotinoides , Receptores Nicotínicos , Tiazinas , Animales , Neonicotinoides/farmacología , Receptores Nicotínicos/metabolismo , Receptores Nicotínicos/genética , Escarabajos/efectos de los fármacos , Escarabajos/genética , Escarabajos/metabolismo , Tiazinas/farmacología , Tiazinas/metabolismo , Tiazinas/toxicidad , Glutatión Transferasa/metabolismo , Glutatión Transferasa/genética , Insecticidas/toxicidad , Insecticidas/farmacología , Insecticidas/metabolismo , Larva/efectos de los fármacos , Larva/metabolismo , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Inactivación Metabólica , Acetilcolinesterasa/metabolismo , Acetilcolinesterasa/genética , Piridinas/farmacología

RESUMEN

The present study focused on the isolation and identification of CP and TCP bacteria degrading bacteria from the rhizospheric zone of aromatic grasses i.e. palmarosa (Cymbopogon martinii (Roxb. Wats), lemongrass (Cymbopogon flexuosus) and vetiver (Chrysopogon zizaniodes (L.) Nash.). So that these isolates alone or in combination with the vegetation of aromatic grasses will be used to clean up CP-contaminated soils. The study also explored enzymatic activities, CO2 release, dechlorination potential, and degradation pathways of bacterial strains. A total of 53 CP-tolerant bacteria were isolated on their physical characteristics and their ability to degrade CP. The ten highly CP-tolerant isolates were Pseudomonas aeruginosa Pa608, three strains of Pseudomonas hibiscicola R4-721 from different rhizosphere, Enterococcus lectis PP2a, Pseudomonas monteilii NBFPALD_RAS131, Enterobacter cloacae L3, Stenotrophomonas maltophilia PEG-390, Escherichia coli ABRL132, and Escherichia coli O104:H4 strain FWSEC0009. The CO2 emission and phosphatase activities of the isolates varied from 3.1 to 8.6 µmol mL-1 and 12.3 to 31 µmol PNP h-1, respectively in the CP medium. The degradation kinetics of CP by these isolates followed a one-phase decay model with a dissipation rate ranging from 0.048 to 0.41 d-1 and a half-life of 1.7-14.3 days. The growth data fitted in the SGompertz equation showed a growth rate (K) of 0.21 ± 0.28 to 0.91 ± 0.33 d-1. The P. monteilii strain had a faster growth rate while E. coli ABRL132 had slower growth among the isolates. The rate of TCP accumulation calculated by the SGompertz equation was 0.21 ± 0.02 to 1.18 ± 0.19 d-1. The Pseudomonas monteilii showed a lower accumulation rate of TCP. Among these, four highly effective isolates were Pseudomonas aeruginosa Pa608, Pseudomonas monteilii NBFPALD_RAS131, Stenotrophomonas maltophilia PEG-390, and Pseudomonas hibiscicola R4-721. Illustrations of the degradation pathways indicated that the difference in metabolic pathways of each isolate was associated with their growth rate, phosphatase, dehydrogenase, oxidase, and dechlorination activities.

Asunto(s)

Biodegradación Ambiental , Cloropirifos , Cinética , Cloropirifos/metabolismo , Bacterias/metabolismo , Bacterias/clasificación , Contaminantes del Suelo/metabolismo , Microbiología del Suelo , Rizosfera , Pseudomonas aeruginosa/metabolismo , Pseudomonas/metabolismo , Insecticidas/metabolismo , Dióxido de Carbono/metabolismo , Cymbopogon/metabolismo