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1.
J Med Chem ; 64(1): 768-781, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33440945

RESUMO

Berberine (BBR), a traditional Chinese medicine, has therapeutic effects on a variety of inflammation-related diseases, but its direct proteomic targets remain unknown. Using activity-based protein profiling, we first demonstrated that BBR directly targets the NEK7 protein via the hydrogen bond between the 2,3-methylenedioxy and 121-arginine (R121) residues. The fact that R121 is located precisely within the key domain involved in the NEK7-NLRP3 interaction allows BBR to specifically block the NEK7-NLRP3 interaction and successively inhibit IL-1ß release, independent of the NF-κB and TLR4 signaling pathways. Moreover, BBR displays in vivo anti-inflammatory efficacy in a NEK7-dependent manner. Therefore, we consider NEK7 to be a key target of BBR in the treatment of NLRP3-related inflammatory diseases, and the development of novel NEK7-NLRP3 interaction inhibitors might be easily achieved using NEK7 as a target.

2.
Arterioscler Thromb Vasc Biol ; : ATVBAHA120314156, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33441025

RESUMO

OBJECTIVE: Reverse cholesterol transport, removing excess cholesterol from peripheral tissues, is an important therapeutic target for atherosclerosis treatment. In this study, we propose a new small molecule, E17241, that may be used to treat atherosclerosis by promoting reverse cholesterol transport via ABCA1 (ATP-binding cassette transporter A1) upregulation. Approach and Results: E17241 (4-(1,3-dithiolan-2-yl)-N-(3-hydroxypyridin-2-yl)benzamide) was first identified as an ABCA1 upregulator using a cell-based reporter assay. E17241 significantly increases the mRNA and protein expression levels of ABCA1 in both hepatic cells and macrophages. It promotes cholesterol efflux to apo AI in macrophage cells, and this effect depends on ABCA1. It also decreases total cholesterol content in Ox-LDL (oxidized low-density lipoprotein) loading macrophage cells. E17241 treatment increases the content of 3H-labeled cholesterol in the feces of male C57BL/6J mice intraperitoneally injected with 3H-cholesterol-labeled macrophage J774 cells, indicating that it could promote in vivo macrophage reverse cholesterol transport. Compared with the western diet group (western diet-fed male ApoE-/- mice), the E17241 group (western diet+E17241 treatment) shows decreased plasma cholesterol, liver cholesterol, and triglyceride levels, with increased fecal cholesterol content. Importantly, E17241 reduces atherosclerotic lesion areas in the en face aorta and aortic sinus while increasing ABCA1 protein levels in both liver and macrophages. Human proteome microarray, coimmunoprecipitation, and other assays demonstrate that PKCζ (protein kinase C zeta) is a binding target of E17241, and this small molecule increases ABCA1 expression in macrophages via the PKCζ-NR (nuclear receptor) pathway. CONCLUSIONS: E17241 may be developed as a new lead or drug candidate for the treatment of atherosclerosis by upregulating ABCA1.

3.
Ecotoxicology ; 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33443714

RESUMO

Bioaugmentation, a strategy based on microbiome engineering, has been proposed for bioremediation of pollutant-contaminated environments. However, the complex microbiome engineering processes for soil bioaugmentation, involving interactions among the exogenous inoculum, soil environment, and indigenous microbial microbiome, remain largely unknown. Acetamiprid is a widely used neonicotinoid insecticide which has caused environmental contaminations. Here, we used an acetamiprid-degrading strain, Pigmentiphaga sp. D-2, as inoculum to investigate the effects of bioaugmentation on the soil microbial community and the process of microbiome reassembly. The bioaugmentation treatment removed 94.8 and 92.5% of acetamiprid within 40 days from soils contaminated with 50 and 200 mg/kg acetamiprid, respectively. A decrease in bacterial richness and diversity was detected in bioaugmentation treatments, which later recovered with the removal of acetamiprid from soil. Moreover, the bioaugmentation treatment significantly influenced the bacterial community structure, whereas application of acetamiprid alone had little influence on the soil microbial community. Furthermore, the bioaugmentation treatment improved the growth of bacteria associated with acetamiprid degradation, and the inoculated and recruited taxa significantly influenced the keystone taxa of the indigenous microbiome, resulting in reassembly of the bacterial community yielding higher acetamiprid-degrading efficiency than that of the indigenous and acetamiprid-treated communities. Our results provide valuable insights into the mechanisms of microbiome engineering for bioaugmentation of acetamiprid-contaminated soils.

4.
Front Med ; 2020 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-33369711

RESUMO

Zika virus (ZIKV) is an emerging pathogen associated with neurological complications, such as Guillain-Barré syndrome in adults and microcephaly in fetuses and newborns. This mosquito-borne flavivirus causes important social and sanitary problems owing to its rapid dissemination. However, the development of antivirals against ZIKV is lagging. Although various strategies have been used to study anti-ZIKV agents, approved drugs or vaccines for the treatment (or prevention) of ZIKV infections are currently unavailable. Repurposing clinically approved drugs could be an effective approach to quickly respond to an emergency outbreak of ZIKV infections. The well-established safety profiles and optimal dosage of these clinically approved drugs could provide an economical, safe, and efficacious approach to address ZIKV infections. This review focuses on the recent research and development of agents against ZIKV infection by repurposing clinical drugs. Their characteristics, targets, and potential use in anti-ZIKV therapy are presented. This review provides an update and some successful strategies in the search for anti-ZIKV agents are given.

5.
Asia Pac J Clin Nutr ; 29(4): 681-689, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33377361

RESUMO

BACKGROUND AND OBJECTIVES: This study aimed to describe and analyze the research outputs on enteral nutrition, which is the administration of food through the gastrointestinal tract for nutrition maintenance. METHODS AND STUDY DESIGN: We searched the Web of Science Core Collection database for original publications on enteral nutrition research from 2010 to 2019. HistCite and VOSviewer software were used for analysis and visualization of the publication outputs, journals, institutions, keywords, cocitations, and collaborations among authors in different countries or regions. RESULTS: A total of 963 relevant articles were included. The number of publications in 2010 and 2019 were 68 and 139, respectively. Nutrition in Clinical Practice and the Journal of Parenteral and Enteral Nutrition had the highest number of publications and cocitations (76, 7.89%; 2058), respectively. The United States and China were the top contributors, accounting for 24.1% and 22.3% of the total articles, respectively. Andrew S. Day and Stephen A. McClave were core researchers in this field. Primary authors collaborated closely. Enteral nutrition, parenteral nutrition, and support were the three most common keywords. The top 10 cocited references concerned administering early enteral nutrition therapy in acutely ill patients and patients with acute Crohn's disease. Crohn's disease, acute pancreatitis, upper gastrointestinal malignancy, and other surgical diseases were among the research hotspots. CONCLUSIONS: Our findings can help researchers identify notable research trends and clinically relevant articles. New catheterization technologies are a future research direction.

6.
J Biosci Bioeng ; 130(6): 630-636, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32958392

RESUMO

To achieve the high-level stable expression of chlorothalonil hydrolytic dehalogenase (Chd), the gene chd was first integrated into the chromosome of Bacillus subtilis WB800. High generation stability was achieved by almost no gene lost after six generations but Chd activity decreased. aprE promoter alteration, translation initiation region modification and multi-copy chromosome integration were studied and these modifications could increase Chd activity by 270%, 2304% and 25%. Chlorothalonil residual exhibited inhibition on bioconversion of lignocellulosic biomass. The addition of Chd crude enzyme (60 µL per g wheat straw) could increase glucose production by 36.10% and 39.65% in synergistic hydrolysis and separate hydrolysis by laccase and cellulase with 120 mg/L residual chlorothalonil. Filter paper activity and carboxymethyl cellulase activity were enhanced by 12.84% and 23.95%, and biomass of Trichoderma reesei was increased by 76.67% under 50 µg chlorothalonil/g dry straw in solid-state fermentation. Thus, the high-level stable expressed Chd effectively eliminated chlorothalonil inhibition on enzymatic hydrolysis and solid-state fermentation. It showed promising potential for bioremediation of chlorothalonil pollution and improving conversion efficiency of lignocellulose.


Assuntos
Bacillus subtilis/enzimologia , Biomassa , Enzimas/genética , Enzimas/metabolismo , Lignina/metabolismo , Nitrilos/metabolismo , Celulase/metabolismo , Fermentação , Expressão Gênica , Hidrólise , Hypocreales/metabolismo , Lacase/metabolismo
7.
Sci Total Environ ; 746: 140992, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32745849

RESUMO

The environmental fate of the recalcitrant organic chlorine insecticide lindane and its removal from contaminated soils are still of great concern. However, the key factors influencing microbial removal of lindane from paddy soils with intermittent flooding and draining remain largely unknown. Here, we conducted laboratory experiments to investigated lindane biodegradation in different layers of typical acidic paddy soils under different water managements and bioremediation strategies, together with the changes of functional bacterial consortium, key genes and metabolic pathways. It was found that under flooded conditions, lindane spiking significantly stimulated the growth of some bacterial genera with potential anaerobic catabolic functions in both top- (0-20 cm depth) and subsoil (20-40 cm depth), leading to the shortest half-life of lindane with 7.6-9.0 d in the topsoil. In contrary, lindane spiking dramatically stimulated the growth of bacterial members with aerobic catabolic functions under drained conditions, exhibiting half-lives of lindane with 85-131 d and 18-23 d in the top- and subsoil, respectively. Overall, biostimulation coupled with flooding management would be the better combination for increased lindane bioremediation. Functional genes involved in lindane degradation and retrieved from metagenomic data further supported the anaerobic and aerobic biodegradation of lindane under flooded and drained conditions, respectively. Moreover, the integrated network analysis suggested water management and organic matter were the primary factors shaped the assembly of functional bacteria in lindane degradation, among which Clostridium and Rhodanobacter were the key anaerobic and aerobic functional genera, respectively. Taken together, our study provides a comprehensive understanding of lindane biodegradation in distinct layers of acidic paddy soils that were combinedly affected by different water managements and bioremediation strategies.


Assuntos
Hexaclorocicloexano , Poluentes do Solo/análise , Biodegradação Ambiental , Solo , Microbiologia do Solo , Água , Abastecimento de Água
8.
J Clin Virol ; 130: 104564, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32763811

RESUMO

BACKGROUND: Occult HBV infection (OBI) is of great concern due to their complicated diagnosis and potential for public transmission. OBJECTIVE: The study aimed to determine the clinical prevalence of OBI and if viral immune escape-associated mutations contribute to the occurrence of OBI. STUDY DESIGN: A total of 91,037 HBV-infected patients with different related illnesses who were admitted to the Fifth Medical Center of Chinese PLA General Hospital from January 2005 to December 2017 were tested for OBI. Serum samples from 62 patients with OBI manifestations (OBI patients) and 124 matched non-OBI patients were sequenced for possible immune escape-associated mutations within the major hydrophilic region of HBV S protein. HBsAg and HBV DNA levels in representative viral strains were measured. RESULTS: Of the 91,037 tested patients, 487 (0.53 %) were negative for HBsAg but positive for HBV DNA and were defined as OBI patients. The prevalence in different illness categories varied. Immune escape-associated mutations were more frequently detected in OBI patients than in non-OBI patients (59.68 % vs. 35.48 %, P < 0.01), as did the coexistence of multiple mutations (43.55 % vs. 22.58 %, P < 0.01). Specifically, the prevalence rates of sT118 K, sK122R, and sV168A were increased in OBI patients. Strains with sK122R mutants (sK122R, sK122R + D144E, sK122R + C121R + D144E, and sK122R + F134L + D144E) from a follow-up OBI patient all showed significantly lower levels of HBsAg production than a wild-type strain. CONCLUSIONS: The study clarified the clinical prevalence of OBI, verified the influence of immune escape-associated mutations, and identified the role of the sK122R mutation in multiple OBI patients.

10.
Phytochemistry ; 177: 112425, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32535347

RESUMO

Ten undescribed cembrane-type diterpenes boscartins AL-AU, as well as five known analogues were isolated from Boswellia sacra Flueck. The relative configurations of these boscartins were established by extensive spectroscopic analysis of NMR spectra, IR and MS. The absolute configurations of boscartin AL, boscartin AN and isoincensole oxide were unequivocally assigned by single crystal X-ray diffraction. Meanwhile, the absolute configurations of boscartin AM, boscartin AP and boscartin AQ were determined by an empirical in situ formed Rh-complex ECD method. Biological evaluations showed that four compounds exhibited obvious hepatoprotective activities against paracetamol-induced HepG2 cell damage at 10 µM. Regarding neuroprotective activity, some isolates displayed moderate to evident protective effects against glutamate-induced toxicity in primary cultured fetal rat cortical neurons or oxygen-glucose deprivation toxicity in SK-N-SH Cells at 10 µM.


Assuntos
Boswellia , Diterpenos , Acetaminofen , Animais , Cristalografia por Raios X , Células Hep G2 , Estrutura Molecular , Ratos
11.
J Agric Food Chem ; 68(26): 6967-6976, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32530641

RESUMO

Dichlorprop [(RS)-2-(2,4-dichlorophenoxy)propanoic acid; DCPP], an important phenoxyalkanoic acid herbicide (PAAH), is extensively used in the form of racemic mixtures (Rac-DCPP), and the environmental fates of both DCPP enantiomers [(R)-DCPP and (S)-DCPP] mediated by microorganisms are of great concern. In this study, a bacterial strain Sphingopyxis sp. DBS4 was isolated from contaminated soil and was capable of utilizing both (R)-DCPP and (S)-DCPP as the sole carbon source for growth. Strain DBS4 preferentially catabolized (S)-DCPP as compared to (R)-DCPP. The optimal conditions for Rac-DCPP degradation by strain DBS4 were 30 °C and pH 7.0. In addition to Rac-DCPP, other PAAHs such as (RS)-2-(4-chloro-2-methylphenoxy)propanoic acid, 2,4-dichlorophenoxyacetic acid, 4-chloro-2-methylphenoxyacetic acid, and 2,4-dichlorophenoxyacetic acid butyl ester could also be catabolized by strain DBS4. Bioremediation of Rac-DCPP-contaminated soil by inoculation of strain DBS4 exhibited an effective removal of both (R)-DCPP and (S)-DCPP from the soil. Due to its broad substrate spectrum, strain DBS4 showed great potential in the bioremediation of PAAH-contaminated sites.


Assuntos
Ácido 2,4-Diclorofenoxiacético/análogos & derivados , Herbicidas/metabolismo , Sphingomonadaceae/metabolismo , Ácido 2,4-Diclorofenoxiacético/química , Ácido 2,4-Diclorofenoxiacético/metabolismo , Biodegradação Ambiental , Herbicidas/química , Estereoisomerismo
12.
Pain Res Manag ; 2020: 1876862, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32454918

RESUMO

Purified from the roots of the plant Sinomenium acutum, sinomenine is traditionally used in China and Japan for treating rheumatism and arthritis. Previously, we have demonstrated that sinomenine possessed a broad analgesic spectrum in various chronic pain animal models and repeated administration of sinomenine did not generate tolerance. In this review article, we discussed sinomenine's analgesic mechanism with focus on its role on immune regulation and neuroimmune interaction. Sinomenine has distinct immunoregulative properties, in which glutamate, adenosine triphosphate, nitric oxide, and proinflammatory cytokines are thought to be involved. Sinomenine may alter the unbalanced neuroimmune interaction and inhibit neuroinflammation, oxidative stress, and central sensitization in chronic pain states. In conclusion, sinomenine has promising potential for chronic pain management in different clinical settings.


Assuntos
Analgésicos/farmacologia , Dor Crônica , Morfinanos/farmacologia , Neuroimunomodulação/efeitos dos fármacos , Animais , Dor Crônica/tratamento farmacológico , Dor Crônica/fisiopatologia , Humanos
13.
ACS Sens ; 5(6): 1650-1656, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32466642

RESUMO

The specific detection of pathogens has long been recognized as a vital strategy for controlling bacterial infections. Herein, a novel hydrophilic aromatic-imide-based thermally activated delayed fluorescence (TADF) probe, AI-Cz-Neo, is designed and synthesized by the conjugation of a TADF emitter with a bacterial 16S ribosomal RNA-targeted moiety, neomycin. Biological data showed for the first time that AI-Cz-Neo could be successfully applied for the dual-mode detection of bacterial 16S rRNA using confocal fluorescence imaging and time-resolved fluorescence imaging (TRFI) in both cells and tissues. These findings greatly expand the application of TADF fluorophores in time-resolved biological imaging and provide a promising strategy for the precise and reliable diagnosis of bacterial infections based on the dual-mode imaging of bacterial 16S rRNA by fluorescence intensity and fluorescence lifetime.

15.
Environ Res ; 183: 109258, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32311908

RESUMO

Nicotine, the major alkaloid in tobacco, is a toxic, carcinogenic, and addictive compound. In recent years, nicotine catabolism in prokaryotes, including the catabolic pathways for its degradation and the catabolic genes that encode the enzymes of these pathways, have been systemically investigated. In this review, the three known pathways for nicotine catabolism in bacteria are summarized: the pyridine pathway, the pyrrolidine pathway, and a variation of the pyridine and pyrrolidine pathway (VPP pathway). The three nicotine catabolic pathways appear to have evolved separately in three distantly related lineages of bacteria. However, the general mechanism for the breakdown of the nicotine molecule in all three pathways is conserved and can be divided into six major enzymatic steps or catabolic modules that involve hydroxylation of the pyridine ring, dehydrogenation of the pyrrolidine ring, cleavage of the side chain, cleavage of the pyridine ring, dehydrogenation of the side chain, and deamination of pyridine ring-lysis products. In addition to summarizing our current understanding of nicotine degradation pathways, we identified several potential nicotine-degrading bacteria whose genome sequences are in public databases by comparing the sequences of conserved catabolic enzymes. Finally, several uncharacterized genes that are colocalized with nicotine degradation genes and are likely to be involved in nicotine catabolism, including regulatory genes, methyl-accepting chemotaxis protein genes, transporter genes, and cofactor genes are discussed. This review provides a comprehensive overview of the catabolism of nicotine in prokaryotes and highlights aspects of the process that still require additional research.


Assuntos
Bactérias , Nicotina , Tabaco , Bactérias/metabolismo , Proteínas de Bactérias , Nicotina/metabolismo
16.
J Agric Food Chem ; 68(15): 4335-4345, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32207940

RESUMO

The phenylurea herbicide linuron is globally used and has caused considerable concern because it leads to environmental pollution. In this study, a highly efficient linuron-transforming strain Sphingobium sp. SMB was isolated, and a gene (lahB) responsible for the hydrolysis of linuron to 3,4-dichloroaniline and N,O-dimethylhydroxylamine was cloned from the genome of strain SMB. The lahB gene encodes an amidohydrolase, which shares 20-53% identity with other biochemically characterized amidohydrolases, except for the newly reported linuron hydrolase Phh (75%). The optimal conditions for the hydrolysis of linuron by LahB were determined to be pH 7.0 and 30 °C, and the Km value of LahB for linuron was 37.3 ± 1.2 µM. Although LahB and Phh shared relatively high identity, LahB exhibited a narrow substrate spectrum (specific for linuron) compared to Phh (active for linuron, diuron, chlortoluron, etc.). Sequence analysis and site-directed mutagenesis revealed that Ala261 of Phh was the key amino acid residue affecting the substrate specificity. Our study provides a new amidohydrolase for the specific hydrolysis of linuron.


Assuntos
Amidoidrolases/química , Amidoidrolases/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Linurona/metabolismo , Sphingomonadaceae/enzimologia , Amidoidrolases/genética , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Estabilidade Enzimática , Herbicidas/metabolismo , Cinética , Filogenia , Alinhamento de Sequência , Sphingomonadaceae/química , Sphingomonadaceae/classificação , Sphingomonadaceae/genética , Especificidade por Substrato
17.
Pharmacol Ther ; 209: 107496, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32001311

RESUMO

Berberine (BBR) is a multi-target drug (MTD) that has proven effective in the treatment of metabolism-related chronic diseases (CDs). However, the mode of action (MOA) of BBR remains to be clarified. At a cellular level, the inhibitory effect of BBR on mitochondrial enzymes is probably responsible for many of its biological activities, including the activation of low-density lipoprotein receptor (LDLR), AMP-activated protein kinase (AMPK) and insulin receptor (InsR); these biological activities contribute to ameliorate peripheral blood metabolic profiles, e.g. by reducing plasma lipids and glucose levels, thus improving signs and symptoms of metabolic disorders. In this perspective, BBR acts as a targeted therapy. However, it also exerts pleiotropic systemic activities on some root causes of CDs that include antioxidant / anti-inflammatory effects and modifications of gut microbiota composition and metabolism, which may also contribute to its disease-modifying effects. After reviewing the different MOA of BBR, here we propose that BBR acts through a drug-cloud (dCloud) mechanism, as different to a drug-target effect. The dCloud here is defined as a group of terminal molecular events induced by the drug (or/and related metabolites), as well as the network connections among them. In this scenario, the therapeutic efficacy of BBR is the result of its dCloud effect acting on symptoms/signs as well as on root causes of the diseases. The dCloud concept is applicable to other established MTDs, such as aspirin, metformin, statins as well as to nutrient starvation, thus providing a novel instrument for the design of effective therapies against multifactorial metabolism-related CDs.

19.
Microb Cell Fact ; 19(1): 4, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31910844

RESUMO

BACKGROUND: Swep is an excellent carbamate herbicide that kills weeds by interfering with metabolic processes and inhibiting cell division at the growth point. Due to the large amount of use, swep residues in soil and water not only cause environmental pollution but also accumulate through the food chain, ultimately pose a threat to human health. This herbicide is degraded in soil mainly by microbial activity, but no studies on the biotransformation of swep have been reported. RESULTS: In this study, a consortium consisting of two bacterial strains, Comamonas sp. SWP-3 and Alicycliphilus sp. PH-34, was enriched from a contaminated soil sample and shown to be capable of mineralizing swep. Swep was first transformed by Comamonas sp. SWP-3 to the intermediate 3,4-dichloroaniline (3,4-DCA), after which 3,4-DCA was mineralized by Alicycliphilus sp. PH-34. An amidase gene, designated as ppa, responsible for the transformation of swep into 3,4-DCA was cloned from strain SWP-3. The expressed Ppa protein efficiently hydrolyzed swep and a number of other structural analogues, such as propanil, chlorpropham and propham. Ppa shared less than 50% identity with previously reported arylamidases and displayed maximal activity at 30 °C and pH 8.6. Gly449 and Val266 were confirmed by sequential error prone PCR to be the key catalytic sites for Ppa in the conversion of swep. CONCLUSIONS: These results provide additional microbial resources for the potential remediation of swep-contaminated sites and add new insights into the catalytic mechanism of amidase in the hydrolysis of swep.


Assuntos
Amidoidrolases/metabolismo , Bactérias/metabolismo , Biodegradação Ambiental , Herbicidas/metabolismo , Amidoidrolases/genética , Clorprofam/metabolismo , Clonagem Molecular , Comamonadaceae/metabolismo , Comamonas/metabolismo , Poluentes Ambientais/metabolismo , Hidrólise , Consórcios Microbianos , Fenilcarbamatos/metabolismo , Propanil/metabolismo
20.
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
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