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1.
Ecotoxicol Environ Saf ; 205: 111141, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32846294

RESUMO

Lactofen is a chiral herbicide and widely used against broadleaf weeds in agriculture. As a pesticide, it is directly released to the environment, and easily caused contamination in soil and aquatic ecosystem. The enantioselective degradation of lactofen in the environment has been reported, but the molecular biological mechanism of this phenomenon is still unclear. In this study, strain Edaphocola flava HME-24 could degrade 96.7% of 50 mg L-1 lactofen within 72 h. Lactofen was initially hydrolyzed to desethyl lactofen and subsequently acifluorfen by strain HME-24. A novel gene lanE, involved in lactofen transformation, was obtained from Edaphocola flava HME-24. Gene lanE encoded a protein of 471 amino acids that contained the conserved GXSXG esterase motif and clustered into esterase subfamily V. LanE shared the highest identity with esterase EstD (Q9WYH1) from Thermotoga maritima MSB8 (29.14%). This esterase was also able to transform p-nitrophenyl esters (C4-C8), and the activity decreased when the carbon chain length increased. LanE showed enantioselectivity during the degradation of lactofen, diclofop-methyl, and quizalofop-ethyl, with a higher degradation efficiency of (S)-enantiomers than (R)-enantiomers. The three-dimensional structure of LanE was simulated, and molecular docking revealed that when the (S)-enantiomers of lactofen occupied the active sites, the distance between the ligand molecule and the coordination atom was shorter than that when the (R)-enantiomers occupied the active sites, which facilitated the formation of the transition state complex. The results in this study enhanced our understanding of the preferential catabolism of the (S)-enantiomers of lactofen on the molecular level and could illustrate the reported enantioselective degradation of lactofen in the environment.


Assuntos
Esterases/metabolismo , Éteres Difenil Halogenados/química , Herbicidas/química , Bacteroidetes/enzimologia , Biodegradação Ambiental , Ecossistema , Simulação de Acoplamento Molecular , Nitrobenzoatos , Praguicidas , Estereoisomerismo
2.
PLoS One ; 15(7): e0228835, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649665

RESUMO

The mosquito Culex erythrothorax Dyar is a West Nile virus (WNV) vector that breeds in wetlands with emergent vegetation. Urbanization and recreational activities near wetlands place humans, birds and mosquitoes in close proximity, increasing the risk of WNV transmission. Adult Cx. erythrothorax abundance peaked in a wetland bordering the San Francisco Bay of California (USA) during the first 3 hours after sunset (5527 ± 4070 mosquitoes / trap night) while peak adult Culex tarsalis Coquillett abundance occurred during the subsequent 3 h period (83 ± 30 Cx. tarsalis). When insecticide resistance was assessed using bottle bioassay, Cx. erythrothorax was highly sensitive to permethrin, naled, and etofenprox insecticides compared to a strain of Culex pipiens that is susceptible to insecticides (LC50 = 0.35, 0.71, and 4.1 µg/bottle, respectively). The Cx. erythrothorax were 2.8-fold more resistant to resmethrin, however, the LC50 value was low (0.68 µg/bottle). Piperonyl butoxide increased the toxicity of permethrin (0.5 µg/bottle) and reduced knock down time, but a higher permethrin concentration (2.0 µg/bottle) did not have similar effects. Bulk mixed-function oxidase, alpha-esterase, or beta-esterase activities in mosquito homogenates were higher in Cx. erythrothorax relative to the Cx. pipiens susceptible strain. There was no difference in the activity of glutathione S-transferase between the two mosquito species and insensitive acetylcholine esterase was not detected. Larvicides that were applied to the site had limited impact on reducing mosquito abundance. Subsequent removal of emergent vegetation in concert with larvicide applications and reduced daily environmental temperature substantially reduced mosquito abundance. To control Cx. erythrothorax in wetlands, land managers should consider vegetation removal so that larvicide can efficiently enter the water. Vector control agencies may more successfully control adult viremic Cx. erythrothorax that enter nearby neighborhoods by applying adulticides during the 3 h that follow sunset.


Assuntos
Culex/fisiologia , Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/toxicidade , Animais , California , Culex/crescimento & desenvolvimento , Esterases/metabolismo , Proteínas de Insetos/metabolismo , Larva/efeitos dos fármacos , Controle de Mosquitos , Permetrina/toxicidade , Butóxido de Piperonila/química , Piretrinas/toxicidade , Áreas Alagadas
3.
J Am Mosq Control Assoc ; 36(1): 22-32, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32497474

RESUMO

In several insect species, resistance to pyrethroids and DDT (dichlorodiphenyltrichloroethane) is linked to point mutations in the voltage-gated sodium channel (VGSC) gene. Pyrethroid-based insecticides prolong the opening of sodium channels, causing paralysis known as a "knockdown" effect before mortality occurs. Point mutations in the VGSC gene result in decreased pyrethroid binding and reduced sensitivity to the insecticide-this resistance mechanism is known as knockdown resistance (kdr) as insects do not die but recover from paralysis with time. In Culex mosquito species loss of target site sensitivity to pyrethroids is linked to a number of substitutions, one of which is leucine (L) to phenylalanine (F) at residue 1014 (L1014F) in the VGSC gene. Here we report the identification of kdr-associated pyrethroid resistance and developing resistance in Cx. quinquefasciatus field collections from Collier County, FL. Evaluation of position 1014 of the VGSC in Cx. quinquefasciatus collections from 7 locations in Collier County, FL, revealed a wide range of genotypes from one part of the district to the other. Centers for Disease Control and Prevention bottle bioassay, linear regression analysis, and cage trial evaluations suggest that the L1014F mutation plays a role, at least in part, to the pyrethroid resistance status of Cx. quinquefasciatus collected in Collier County, FL. Furthermore, we identified resistance attributed to both oxidase and esterase activity, indicating that multiple mechanisms are responsible for pyrethroid resistance in Collier County Cx. quinquefasciatus.


Assuntos
Culex/genética , Esterases/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Oxirredutases/genética , Piretrinas/farmacologia , Animais , Culex/efeitos dos fármacos , Culex/enzimologia , Esterases/metabolismo , Feminino , Florida , Oxirredutases/metabolismo
4.
Toxicol Appl Pharmacol ; 398: 115032, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32387182

RESUMO

BACKGROUND AND PURPOSE: Irinotecan-induced diarrhea (IID) results from intestinal damages by its active metabolite SN-38. Alleviation of these damages has focused on lowering luminal SN-38 concentrations. However, it is unclear if the enteric bioavailability of SN-38 is mostly dependent on luminal SN-38 concentrations. EXPERIMENTAL APPROACH: Irinotecan (50 mg/kg, i.p. once daily for 6 days) was administered to female wildtype FVB, Mdr1a (-/-), Mrp2 (-/-) and Bcrp1 (-/-) mice for pharmacokinetic (PK), toxicokinetic (TK) and biodistribution studies. Plasma PK/TK profiles and tissues drug distribution were determined after first or sixth daily doses, along with activities of blood and gut esterases and intestinal Ugts. Caco-2 cells and bile-cannulate mice were used to further investigate intestinal and biliary disposition of irinotecan and its metabolites. KEY RESULTS: Significant differences in IID severity were observed with the susceptible rank of Bcrp1(-/-) > wildtype FVB > Mdr1a(-/-) > Mrp2(-/-). This rank order did not correlate with biliary excretion rates of SN-38/SN-38G. Rather, the severity was best correlated (R = 0.805) with the intestinal ratio of Css SN-38/SN-38G, a measure of gut Ugt activity. On the contrary, IID was poorly correlated with plasma AUC ratio of SN-38/SN-38G (R = 0.227). Increased intestinal esterase activities due to repeated dosing and gut efflux transporter functionality are the other key factors that determine SN-38 enteric exposures. CONCLUSION AND IMPLICATIONS: Intestinal SN-38 exposure is mainly affected by intestinal Ugt activities and blood esterase activities, and strongly correlated with severity of IID. Modulating intestinal SN-38 concentration and gut Ugt expression should be the focus of future studies to alleviate IID.


Assuntos
Diarreia/induzido quimicamente , Glucuronosiltransferase/metabolismo , Intestinos/efeitos dos fármacos , Irinotecano/farmacologia , Animais , Antineoplásicos Fitogênicos , Área Sob a Curva , Bile/metabolismo , Sistema Biliar/efeitos dos fármacos , Sistema Biliar/metabolismo , Células CACO-2 , Linhagem Celular Tumoral , Diarreia/metabolismo , Esterases/metabolismo , Feminino , Humanos , Camundongos , Distribuição Tecidual/efeitos dos fármacos
5.
J Oleo Sci ; 69(5): 467-477, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32378550

RESUMO

Esterases catalyze the hydrolysis of ester bonds in fatty acid esters with short-chain acyl groups. In the present study, thirty-seven bacterial isolates were isolated from soil contaminated with waste cooking oil, dairy waste etc. from Shimla and Solan district of H.P. Out of 37 isolates, the isolate RL-1, which gave maximum activity, was identified as Bacillus licheniformis MH061919. The optimization of various production parameters resulted in maximum activity at inoculum age of 24 h and inoculum size of 1.5% (v/v). Esterase gave considerable activity in production medium containing sodium chloride (0.5 % w/v), galactose (1%, w/v), coconut oil (2.0%, v/v) and beef extract (0.3%, w/v) at a temperature of 45℃ and pH 8.5.The enzyme production was enhanced by 3-fold after optimization of production parameters. Further, on optimizing reaction conditions, enzyme gave maximum activity at a temperature of 45℃ and pH 8.5. The para-nitrophenyl acetate (p-NPA) was found to be optimum substrate and metal ions and detergents have inhibitory effect on esterase activity.


Assuntos
Bacillus/enzimologia , Meios de Cultura/química , Técnicas de Cultura/métodos , Esterases/metabolismo , Bacillus/isolamento & purificação , Óleo de Coco , Galactose , Concentração de Íons de Hidrogênio , Nitrofenóis/metabolismo , Carne Vermelha , Cloreto de Sódio , Temperatura , Extratos de Tecidos
6.
Proc Natl Acad Sci U S A ; 117(13): 7122-7130, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32170022

RESUMO

ß-mannans and xylans are important components of the plant cell wall and they are acetylated to be protected from degradation by glycoside hydrolases. ß-mannans are widely present in human and animal diets as fiber from leguminous plants and as thickeners and stabilizers in processed foods. There are many fully characterized acetylxylan esterases (AcXEs); however, the enzymes deacetylating mannans are less understood. Here we present two carbohydrate esterases, RiCE2 and RiCE17, from the Firmicute Roseburia intestinalis, which together deacetylate complex galactoglucomannan (GGM). The three-dimensional (3D) structure of RiCE17 with a mannopentaose in the active site shows that the CBM35 domain of RiCE17 forms a confined complex, where the axially oriented C2-hydroxyl of a mannose residue points toward the Ser41 of the catalytic triad. Cavities on the RiCE17 surface may accept galactosylations at the C6 positions of mannose adjacent to the mannose residue being deacetylated (subsite -1 and +1). In-depth characterization of the two enzymes using time-resolved NMR, high-performance liquid chromatography (HPLC), and mass spectrometry demonstrates that they work in a complementary manner. RiCE17 exclusively removes the axially oriented 2-O-acetylations on any mannose residue in an oligosaccharide, including double acetylated mannoses, while the RiCE2 is active on 3-O-, 4-O-, and 6-O-acetylations. Activity of RiCE2 is dependent on RiCE17 removing 2-O-acetylations from double acetylated mannose. Furthermore, transacetylation of oligosaccharides with the 2-O-specific RiCE17 provided insight into how temperature and pH affects acetyl migration on manno-oligosaccharides.


Assuntos
Clostridiales/enzimologia , Esterases/metabolismo , Mananas/metabolismo , Esterases/química , Picea , Conformação Proteica , Especificidade por Substrato
7.
Artigo em Inglês | MEDLINE | ID: mdl-32005389

RESUMO

Salicylic acid (SA) plays an important role in the response of plants to abiotic stresses. Starvation stress affects plant cell metabolic activities, which further limits the normal growth and development of plants. It was reported that SA might play a regulatory role in the process of plant against starvation stress, but the mechanism involved in this process is still unclear. Thus, in this study, the transgenic plants overexpressing a SA binding protein 2 (SABP2) gene were exposed to starvation stress and the transgenic lines showed starvation-tolerant phenotype. Compared with wild-type (WT) plants, transgenic plants showed better growth status under poor-nutrition stress. Transgenic plants also showed more vigorous roots than WT plants. Physiological tests indicated that the transgenic plants showed higher relative water content (RWC), chlorophyll content, photosynthetic capacity, endogenous SA content, and lower ROS level compared to WT plants. Transcriptome analysis of tobacco plants identified 3, 748 differentially expressed genes (DEGs) between transgenic and WT plants under starvation stress. These DEGs are mainly involved in glycolysis/gluconeogenesis pathway group, MAPK signaling pathway group and plant hormone signal transduction pathway group. As determined by qPCR, up-regulated expression of fifteen genes such as abscisic acid receptor PYR1-like gene (NtPYR1-like), bidirectional sugar transporter N3-like gene (NtSWEETN3-like) and superoxide dismutase [Fe] chloroplastic-like gene (NtFeSOD-like), etc., was observed in transgenic plants under poor-nutrition stress which was in accordance with RNA-sequencing results. The modified pathways involved in plant hormone signaling are thought to be at least one of the main causes of the increased starvation tolerance of transgenic tobacco plants with altered SA homeostasis.


Assuntos
Esterases/genética , Regulação da Expressão Gênica de Plantas , Nutrientes/metabolismo , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo , Tabaco/fisiologia , Esterases/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico/genética , Tabaco/genética
8.
Nat Commun ; 11(1): 1026, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32094331

RESUMO

Structural and functional studies were conducted of the glucuronoyl esterase (GE) from Cerrena unicolor (CuGE), an enzyme catalyzing cleavage of lignin-carbohydrate ester bonds. CuGE is an α/ß-hydrolase belonging to carbohydrate esterase family 15 (CE15). The enzyme is modular, comprised of a catalytic and a carbohydrate-binding domain. SAXS data show CuGE as an elongated rigid molecule where the two domains are connected by a rigid linker. Detailed structural information of the catalytic domain in its apo- and inactivated form and complexes with aldouronic acids reveal well-defined binding of the 4-O-methyl-a-D-glucuronoyl moiety, not influenced by the nature of the attached xylo-oligosaccharide. Structural and sequence comparisons within CE15 enzymes reveal two distinct structural subgroups. CuGE belongs to the group of fungal CE15-B enzymes with an open and flat substrate-binding site. The interactions between CuGE and its natural substrates are explained and rationalized by the structural results, microscale thermophoresis and isothermal calorimetry.


Assuntos
Domínio Catalítico , Esterases/metabolismo , Proteínas Fúngicas/metabolismo , Ácido Glucurônico/metabolismo , Polyporales/enzimologia , Carboidratos , Parede Celular/metabolismo , Cristalografia por Raios X , Esterases/isolamento & purificação , Esterases/ultraestrutura , Proteínas Fúngicas/isolamento & purificação , Proteínas Fúngicas/ultraestrutura , Hidrólise , Lignina/metabolismo , Estrutura Secundária de Proteína , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Espalhamento a Baixo Ângulo , Relação Estrutura-Atividade , Especificidade por Substrato , Difração de Raios X
9.
Carbohydr Polym ; 230: 115613, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887935

RESUMO

Targeted and sensitive drug release at the colitis site is critical for the effective therapy of ulcerative colitis and reduction of side effects from the drug. Herein, we used 3,3'-dithiodipropionic acid (DTPA) to covalently link quercetin (Qu) and glyceryl caprylate-caprate (Gcc) via ester bonds to prepare Qu-SS-Gcc lipid nanoparticles (Qu-SS-Gcc LNPs). Dexamethasone (Dex) was used as a model drug, and chitosan (CSO) was modified on the surface of Qu-SS-Gcc LNPs to obtain CSO-modified Dex-loaded Qu-SS-Gcc LNPs (CSO/Dex/LNPs). The encapsulation efficiency and drug loading of CSO/Dex/LNPs were 93.1 % and 8.1 %, respectively. The in vitro release results showed that CSO/Dex/LNPs had esterase-responsive characteristics and could release the drug rapidly in esterase-containing artificial intestinal fluid. A human colorectal adenocarcinoma cell (Caco-2) monolayer was used as the intestinal cell barrier model. Transmembrane resistance measurements and permeation experiments showed that CSO/Dex/LNPs had a protective effect on the lipopolysaccharide (LPS)-stimulated Caco-2 cell monolayer and increased the expression of E-cadherin in LPS-stimulated Caco-2 cells. Moreover, CSO/Dex/LNPs could significantly reduce the expression of the inflammatory factors TNF-α, IL-6 and NO in LPS-stimulated RAW 264.7 cells. The ulcerative colitis mouse model was constructed by using C57BL/6 mice. The in vivo distribution results showed that CSO/Dex/LNPs had colon-targeting effects and strong retention ability in the colons of mice with colitis. The results also showed that CSO/Dex/LNPs had better anti-inflammatory effects than free Dex, which could reduce colonic atrophy, reduce histomorphological changes and increase the expression of E-cadherin in the colon. Furthermore, the expression levels of TNF-α, IL-6 and NO in the CSO/Dex/LNP-treated group were 37.4 %, 35.5 % and 33.2 % of those in mice with colitis, respectively.


Assuntos
Caprilatos/química , Quitosana/análogos & derivados , Colite Ulcerativa/tratamento farmacológico , Portadores de Fármacos/química , Nanopartículas/química , Polímeros Responsivos a Estímulos/química , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico , Células CACO-2 , Colo/efeitos dos fármacos , Colo/metabolismo , Reagentes para Ligações Cruzadas/química , Citocinas/genética , Citocinas/metabolismo , Dexametasona/administração & dosagem , Dexametasona/uso terapêutico , Portadores de Fármacos/efeitos adversos , Esterases/metabolismo , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/efeitos adversos , Óxido Nítrico/metabolismo , Quercetina/administração & dosagem , Quercetina/química , Quercetina/uso terapêutico , Células RAW 264.7
10.
Ecotoxicol Environ Saf ; 190: 110148, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31911388

RESUMO

Phthalate esters have raised public concerns owing to their effects on the environment and human health. We identified a novel phthalate-degrading hydrolase, EstJ6, from a metagenomic library using function-driven screening. Phylogenetic analysis indicated that EstJ6 is a member of family IV esterases. EstJ6 hydrolyzed various dialkyl and monoalkyl phthalate esters, and exhibited high hydrolytic activity (128 U/mg) toward dibutyl phthalate at 40 °C and pH 7.5. EstJ6 hydrolyzed not only common phthalate esters with simple side chains but also diethylhexyl phthalate and monoethylhexyl phthalate, which have complex and long side chains. Site-directed mutagenesis indicated that the catalytic triad residues of EstJ6 consists of Ser146, Glu240, and His270. EstJ6 is therefore a promising biodegradation enzyme, and our study illustrates the advantages of a metagenomic approach in identifying enzyme-coding genes for agricultural, food, and biotechnological applications.


Assuntos
Biodegradação Ambiental , Hidrolases/metabolismo , Ácidos Ftálicos/metabolismo , Dibutilftalato/metabolismo , Dietilexilftalato/metabolismo , Esterases/metabolismo , Ésteres/química , Biblioteca Gênica , Hidrolases/genética , Hidrólise , Metagenoma , Filogenia , Solo
11.
PLoS One ; 15(1): e0227267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31931513

RESUMO

The relevant information about the impacts caused by presence of emerging pollutants in mixtures on the ecological environment, especially on the more vulnerable compartments such as activated sludge (AS) is relatively limited. This study investigated the effect of ibuprofen (IBU) and triclosan (TCS), alone and in combination to the performance and enzymatic activity of AS bacterial community. The assays were carried out in a pilot AS reactor operating for two-weeks under continuous dosage of pollutants. The microbial activity was tracked by measuring oxygen uptake rate, esterase activity, oxidative stress and antioxidant enzyme activities. It was found that IBU and TCS had no acute toxic effects on reactor biomass concentration. TCS led to significant decrease of COD removal efficiency, which dropped from 90% to 35%. Continuous exposure to IBU, TCS and their mixtures increased the activities of glutathione s-transferase (GST) and esterase as a response to oxidative damage. A high increase in GST activity was associated with non-reversible toxic damage while peaks of esterase activity combined with moderate GST increase were attributed to an adaptive response.


Assuntos
Bactérias/enzimologia , Proteínas de Bactérias/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Reatores Biológicos/microbiologia , Poluentes Químicos da Água/toxicidade , Bactérias/efeitos dos fármacos , Biomassa , Esterases/metabolismo , Glutationa Transferase/metabolismo , Ibuprofeno/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Oxigênio/metabolismo , Triclosan/toxicidade , Águas Residuárias/química , Águas Residuárias/toxicidade , Purificação da Água/métodos
12.
Can J Microbiol ; 66(2): 125-137, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31697563

RESUMO

The high frequency and incidence of foodborne outbreaks related to fresh vegetables consumption is a major public health concern and an economic burden worldwide. This study evaluated the effect of individual and combined application of ultrasound (40 kHz, 100 W) and ozone on the inactivation of foodborne Escherichia coli and Salmonella, as well as their impact on cabbage color and vitamin C content. Plate count, scanning electron microscopy (SEM), and flow cytometry (FCM) following single or double staining with carboxyfluorescein diacetate and (or) propidium iodide were used to determine bacterial inactivation parameters, such as cell culturability, membrane integrity, intracellular enzyme activity, and injured and dead cells. The results of FCM and SEM showed that ultrasound treatment affected bacteria mainly by acting on the cell membrane and inactivating intracellular esterase, which resulted in bacterial death. Furthermore, when combined with ozone at 1.5 mg/L, the maximum reduction of bacterial populations was observed at 8 min with no damage on the surface of treated leaves. Therefore, fresh products sanitization using a combination of ultrasound and ozone has the potential to be an alternative for maintaining the color and vitamin C content of green cabbage.


Assuntos
Anti-Infecciosos/farmacologia , Brassica/microbiologia , Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos , Ozônio/farmacologia , Salmonella/efeitos dos fármacos , Ácido Ascórbico/análise , Proteínas de Bactérias/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Brassica/química , Cor , Escherichia coli/crescimento & desenvolvimento , Esterases/efeitos dos fármacos , Esterases/metabolismo , Fluoresceínas , Contaminação de Alimentos/prevenção & controle , Folhas de Planta/química , Folhas de Planta/microbiologia , Propídio , Salmonella/crescimento & desenvolvimento , Ondas Ultrassônicas
13.
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
14.
Ecotoxicol Environ Saf ; 189: 109954, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31759743

RESUMO

Acetylcholinesterase (AChE) and general-esterase (GE) activities are important to understand detoxification processes of xenobiotics. The assays to quantify them have employed different substrates, inhibitors, types of experiments (in vitro and in vivo) and model organisms. The aim of this work was to give a systematic overview of the effect of the above factors on the outcome of AChE and GE activity measurements. We showed that AChE activity could be measured with the substrate acetylthiocholine iodide (AChI) but not with acetylcholine bromide (AChB) and only in in vitro assays. For GE activity, Michaelis-Menten kinetics differed between the substrates 4-methylumbellifery butyrate (4-MUB) and 1-naphtyl acetate (1-NA) in the measurements of in vitro activity, but their inhibition curves and IC50 values for the general inhibitor tetraisopropyl pyrophosphoramide (iso-OMPA) were similar, confirming that both substrates targeted the same group of enzymes. The GE substrate 4-MUB was applicable both in vitro and in vivo, while 1-NA was only applicable in vitro due to its high acute toxicity. When comparing the zooplankton crustacean Daphnia magna and the sediment dwelling Chironomus riparius, the latter had a four-fold higher maximal AChE activity (Vmax) and a higher susceptibility to the AChE inhibitor BW284c51 (four-fold lower 50% inhibitory concentration, IC50), but a lower maximal GE activity and lower susceptibility to iso-OMPA (higher IC50), indicating significant species differences between in C. riparius and D. magna. We conclude that both choice of substrate and exposure method matters for the outcome of esterase assays and that esterase compositions between species may vary significantly.


Assuntos
Acetilcolinesterase/metabolismo , Esterases/metabolismo , Acetiltiocolina/análogos & derivados , Acetiltiocolina/metabolismo , Animais , Benzenamina, 4,4'-(3-oxo-1,5-pentanodi-il)bis(N,N-dimetil-N-2-propenil-), Dibrometo/farmacologia , Chironomidae/efeitos dos fármacos , Chironomidae/enzimologia , Inibidores da Colinesterase/farmacologia , Daphnia/efeitos dos fármacos , Daphnia/enzimologia , Ensaios Enzimáticos , Himecromona/análogos & derivados , Himecromona/metabolismo , Cinética , Naftóis/metabolismo , Xenobióticos/farmacologia
15.
World J Microbiol Biotechnol ; 35(12): 187, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31728656

RESUMO

This review examines the recent models describing the mode of action of various xylanolytic enzymes and how these enzymes can be applied (sequentially or simultaneously) with their distinctive roles in mind to achieve efficient xylan degradation. With respect to homeosynergy, synergism appears to be as a result of ß-xylanase and/or oligosaccharide reducing-end ß-xylanase liberating xylo-oligomers (XOS) that are preferred substrates of the processive ß-xylosidase. With regards to hetero-synergism, two cross relationships appear to exist and seem to be the reason for synergism between the enzymes during xylan degradation. These cross relations are the debranching enzymes such as α-glucuronidase or side-chain cleaving enzymes such as carbohydrate esterases (CE) removing decorations that would have hindered back-bone-cleaving enzymes, while backbone-cleaving-enzymes liberate XOS that are preferred substrates of the debranching and side-chain-cleaving enzymes. This interaction is demonstrated by high yields in co-production of xylan substituents such as arabinose, glucuronic acid and ferulic acid, and XOS. Finally, lytic polysaccharide monooxygenases (LPMO) have also been implicated in boosting whole lignocellulosic biomass or insoluble xylan degradation by glycoside hydrolases (GH) by possibly disrupting entangled xylan residues. Since it has been observed that the same enzyme (same Enzyme Commission, EC, classification) from different GH or CE and/or AA families can display different synergistic interactions with other enzymes due to different substrate specificities and properties, in this review, we propose an approach of enzyme selection (and mode of application thereof) during xylan degradation, as this can improve the economic viability of the degradation of xylan for producing precursors of value added products.


Assuntos
Xilanos/metabolismo , Xilosidases/metabolismo , Arabinose/metabolismo , Biodegradação Ambiental , Ácidos Cumáricos/metabolismo , Endo-1,4-beta-Xilanases , Esterases/metabolismo , Ácido Glucurônico/metabolismo , Glicosídeo Hidrolases , Oligossacarídeos/metabolismo , Polissacarídeos , Especificidade por Substrato , Xilanos/química
16.
Infect Immun ; 88(1)2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31636137

RESUMO

Mycobacterium tuberculosis Rv3775 (LipE) was annotated as a putative lipase. However, its lipase activity has never been characterized, and its precise role in tuberculosis (TB) pathogenesis has not been thoroughly studied to date. We overexpressed and purified the recombinant LipE (rLipE) protein and demonstrated that LipE has a lipase/esterase activity. rLipE prefers medium-chain ester substrates, with the maximal activity on hexanoate. Its activity is the highest at 40°C and pH 9. We determined that rLipE hydrolyzes trioctanoate. Using site-directed mutagenesis, we confirmed that the predicted putative activity triad residues Ser97, Gly342, and His363 are essential for the lipase activity of rLipE. The expression of the lipE gene was induced under stressed conditions mimicking M. tuberculosis' intracellular niche. The gene-disrupting mutation of lipE led to significantly reduced bacterial growth inside THP-1 cells and human peripheral blood mononuclear cell-derived macrophages and attenuated M. tuberculosis infection in mice (with ∼8-fold bacterial load reduction in mouse lungs). Our data suggest that LipE functions as a lipase and is important for M. tuberculosis intracellular growth and in vivo infection.


Assuntos
Esterases/metabolismo , Lipase/metabolismo , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Tuberculose/microbiologia , Fatores de Virulência/metabolismo , Animais , Análise Mutacional de DNA , Modelos Animais de Doenças , Estabilidade Enzimática , Esterases/deficiência , Esterases/genética , Humanos , Concentração de Íons de Hidrogênio , Cinética , Lipase/deficiência , Lipase/genética , Camundongos , Modelos Teóricos , Mutagênese Sítio-Dirigida , Células THP-1 , Temperatura , Fatores de Virulência/genética
17.
Enzyme Microb Technol ; 131: 109331, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31615665

RESUMO

Acinetobacter sp. strain LMB-5 can produce a kind of esterase degrading phthalate esters. However, low activity of Est3563 esterase limited its large-scale application. In this study, computer-aided simulation mutagenesis was used to improve the esterase activity with a tightened screening library and enlarged success rate. Two positive mutants, P218R and A242R, were obtained with 2.5 and 2.1 folds higher than the WT Est3563 esterase, with 11.96 ± 0.45 U·mg-1 and 9.90 ± 0.52 U·mg-1, respectively. With the help of bioinformatics analysis and three-dimensional printing technology, it was found that the mutations could increase the 240-280 residues swing distance and make them deviate from the catalytic pocket. The instability and deviation of these residues on the lid-like structure of the esterase could deteriorate the seal of the binding pocket and expose the active site. Thus, the catalytic efficiency of the mutants became higher. This result demonstrates that the instability and deviation of the lid-like structure could expand the binding pocket of the esterase and enhance the esterase activity.


Assuntos
Acinetobacter/enzimologia , Esterases/metabolismo , Ácidos Ftálicos/metabolismo , Biologia Computacional , Esterases/química , Esterases/genética , Cinética , Simulação de Dinâmica Molecular , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Mutação de Sentido Incorreto , Conformação Proteica
18.
J Basic Microbiol ; 59(12): 1173-1184, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31621083

RESUMO

Lipids are hydrocarbons comprised of long-chain fatty acids and are found in all living things. In the environment, microorganisms degrade them to obtain energy using esterases and lipases. These enzymes are nowadays used in different industrial applications. We report isolation of 24 bacteria with esteresic and lipolytic activity from Lake Magadi, Kenya. The isolates were characterised using morphological, biochemical, and molecular methods. Isolates grew at an optimum salt concentration of 5-8% (w/v), pH range of 8.0-9.0, and temperature range of 35-40°C. The isolates were positive for esterase and lipase assay as well as other extracellular enzymes. Phylogenetic analysis of the 16S ribosomal RNA gene showed that the isolates were affiliated to the genus Bacillus, Alkalibacterium, Staphylococcus, Micrococcus, Halomonas, and Alkalilimnicola. None of the bacterial isolates produced antimicrobial agents, and all of them were resistant to trimethoprim and nalidixic acid but susceptible to streptomycin, amoxillin, chloramphenicol, and cefotaxime. Growth at elevated pH, salt, and temperature is an indicator that the enzymes from these organisms could function well under haloalkaline conditions. Therefore, Lake Magadi could be a good source of isolates with the potential to produce unique biocatalysts for the biotechnology industry.


Assuntos
Bactérias/classificação , Bactérias/enzimologia , Biodiversidade , Esterases/metabolismo , Lagos/microbiologia , Lipase/metabolismo , Microbiologia da Água , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/genética , DNA Bacteriano/genética , Esterases/genética , Concentração de Íons de Hidrogênio , Quênia , Lagos/química , Lipase/genética , Testes de Sensibilidade Microbiana , Filogenia , RNA Ribossômico 16S/genética , Tolerância ao Sal , Análise de Sequência de DNA , Temperatura
19.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 50(3): 291-297, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31631592

RESUMO

Objective: To explore the biological characteristics of the esterase LipR encoded by Mycobacterium tuberculosis (MTB) Rv3084 and its immunomodulatory function in vivo. Methods: The LipR gene was amplified from MTB H37Rv strain to construct recombinant expression plasmid. After sequencing, the recombinant plasmid was transformed into E. coli for expression and purification of LipR protein. The expressed protein was confirmed with Western blot assay. The hydrolyzing activity of LipR was detected and the factors affecting LipR enzyme activity were analyzed. Mice were intramuscularly injected with 0.1 mL (containing plasmid DNA 100 µg) recombinant eukaryotic plasmid three times (day 1, 8, and 15); seven days after the last injection, the mice were executed, and the lung and spleen were taken for cytokine detection. Results: The recombinant expression plasmid was successfully constructed and it was found that LipR protein was mainly expressed in the form of inclusion bodies in E. coli with the relative molecular mass of about 33×10 3. LipR was demonstrated as an alkaline eurythermic esterase, due to the preference of hydrolyzing short carbon chain esters with optimal hydrolyzing activity on pNP-acetate (pNPA, C2) and the capability in tolerance of high pH and temperature; in the presence of different detergents or metal ions, the activity of LipR hydrolyzing pNP-butyrate (pNPB, C4) was inhibited to some extent. In the mouse model, it was found that LipR could inhibit the secretion of interferon-γ (IFN- γ) and interleukin-2 (IL-2), but to stimulate the secretion of IL-10. Conclusion: The esterase LipR may be one of the esterases help M. tuberculosis withstand harsh environment inside the host in collaboration, and simultaneously act as an immune modulator to inhibit the secretion of pro-inflammatory cytokines and consequently impact the killing effect of host immune system against M. tuberculosis.


Assuntos
Proteínas de Bactérias/metabolismo , Esterases/metabolismo , Interferon gama/imunologia , Interleucina-10/imunologia , Interleucina-2/imunologia , Mycobacterium tuberculosis/enzimologia , Animais , Camundongos
20.
J Toxicol Sci ; 44(10): 693-699, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31588060

RESUMO

Cigarette smoking is a risk factor for the development of various cancers, such as lung, nasal, liver and bladder cancers. 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific nitrosamine, is implicated in human lung cancer. NNK-induced DNA adducts are found in target tissues for NNK carcinogenesis. NNK is activated by cytochrome P450 dependent α-hydroxylation at either the methylene carbon or methyl carbon adjacent to the N-nitroso group. The former leads to the formation of the methylating agent, and the latter produce the pyridyloxobutylating agent. NNK and some of its metabolites are further metabolized by UDP-glucuronosyltransferases (UGTs). Glucuronides generally are much less active than the parent aglycon therefore the glucuronides of NNK-related metabolites are thought to be inactive. However, 4-(hydroxymethylnitrosamino)-1-(3-pyridyl)-1-butanone glucuronide (HO-methyl NNK glucuronide) can be transported to the target organs of NNK carcinogenesis where subsequent hydrolysis causes the release of the reactive intermediate. Regeneration of HO-methyl NNK could play an important role in the tissue-specific carcinogenicity of NNK. In the present study, we investigated the reactivity of HO-methyl NNK glucuronide toward 2'-deoxyguanosine (dGuo) and N-acetylcysteine (NAC; used as a models for thiol groups on proteins). The reaction mixtures of HO-methyl NNK glucuronide and dGuo or NAC were analyzed by LCMS-IT-TOF-MS. We also employed 4-(acetoxymethylnitrosamino)-1-(3-pyridyl)-1-butanone, a pyridyloxobutylating agent, to confirm the formation of pyridyloxobutylated adducts. Thus, we determined the production of pyridyloxobutylated dGuo and NAC adducts. Our results suggest HO-methyl NNK glucuronide could generate a reactive intermediate in the tissues and then form adducts with proteins and DNA.


Assuntos
Acetilcisteína/metabolismo , Carcinógenos/toxicidade , Adutos de DNA , Desoxiguanosina/metabolismo , Glucuronídeos/toxicidade , Nitrosaminas/toxicidade , Animais , Esterases/metabolismo , Fígado/metabolismo , Camundongos
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