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The Susceptibilities of Oxya chinensis(Orthoptera:Acridoidea) to Malathion and Comparison of the Esterase Properties from Three Collected Populations in Tianjin Area,China

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Agricultural Sciences in China 2009年第1期8卷 76-82页

作者： WU Hai-hua YANG Mei-ling GUO Ya-ping MA En-bo Institute of Applied Biology Shanxi University Taiyuan 030006 P.R.China

The susceptibilities of Oxya chinensis to malathion were studied in three populations collected from outskirt of Tianjin, China, using bioassays and biochemical analysis. Populations were chosen to represent different exposure to insecticides： BDG （Beidagang; low exposure）, BD （Baodi; high exposure previously but low exposure now）, and JN （Jinnan; high exposure）. The results showed that the LD50 values of BD and JN populations were 3.95- and 12.02-fold and 3.64- and 10.07- fold higher than that of BDG population in females and males, respectively. The LD50 values in females were higher than those in males. The results of biochemical analysis indicated that the esterase （EST） activities in JN population were higher than those in BD and BDG populations. They showed that when α-NA, α-NB, and α-NA were used as substrates, females＇ EST activities of JN population were 1.11-, 1.30-, and 1.14-fold and 1.39-, 1.59-, and 1.54-fold higher than those of BD and BDG populations, respectively. When α-NA, α-NB, and β-NA were used as substrates, males＇ EST activities of JN population were 1.13-, 1.12-, and 1,00-fold and 1.20-, 1.14-, and 1.07-fold higher than those of BD and BDG populations, respectively. The results also showed that the specific activities of the females were higher than those of the males in the BD and JN populations, whereas the specific activities of the males were higher than those of the females in the BDG population. The results of bioassay were consistent with those of biochemical analysis. Thus, it was inferred that the elevated ESTs activities might play an important role in conferring the differences of susceptibility of O. chinensis to malathion in the three collected populations. enzyme kinetic studies indicated that the Km and Vmax values were different among the three collected populations and between the females and the males. The observed changes in the kinetic parameters might be explained by differential expression patterns of isozymes so that th

关键词： Oxya chinensis esterase enzyme kinetics malathion susceptibility

Heterologous expression and characterization of two chitinase 5 enzymes from the migratory locust Locusta migratoria

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Insect Science 2016年第3期23卷 406-416页

作者： Ying-Long Li Hui-Fang Song Xue-Yao Zhang Da-Qi Li Ting-Ting Zhang En-Bo Ma Jian-Zhen Zhang Research Institute of Applied Biology College of Life Science Shanxi University Taiyuan China

Insect chitinases are involved in degradation of chitin from the exoskeleton or peritrophic metrix ofmidgut. In Locusta migratoria, two duplicated Cht5s （LmCht5-1 and LmCht5-2） have been shown to have distinct molecular characteristics and biological roles. To explore the protein properties of the two LmCht5s, we heterologously expressed both enzymes using baculovirus expression system in SF9 cells, and characterized kinetic and carbohydrate-binding properties of purified enzymes. LmCht5-1 and LmCht5-2 exhibited similar pH and temperature optimums. LmCht5-1 has lower Km value for the oligomeric substrate （4MU-（GlcNAe）3）, and higher Km value for the longer substrate （CM-Chitin- RBV） compared with LmCht5-2. A comparison of amino acids and homology modeling of catalytic domain presented similar TIM barrel structures and differentiated amino acids between two proteins. LmCht5-1 has a chitin-binding domain （CBD） tightly bound to colloidal chitin, but LmCht5-2 does not have a CBD for binding to colloidal chitin. Our results suggested both LmCht5- I and LmCht5-2, which have the critical glutamate residue in region II of catalytic domain, exhibited chitinolytic activity cleaving both polymeric and oligomeric substrates. LmCht5-1 had relatively higher activity against the oligomeric substrate, 4MU-（GlcNAc）3, whereas LmCht5-2 exhibited higher activity toward the longer substrate, CM-Chitin-RBE These findings are helpful for further research to clarit}g their different roles in insect growth and development.

关键词： chitinase 5 enzyme kinetics heterologous expression Locusta migratoria

Characterization of Carboxylesterase Associated with Malathion Insensitivity in the Field Population of the Oriental Migratory Locust

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Agricultural Sciences in China 2008年第5期7卷 591-598页

作者： YANG Mei-ling ZHANG Jian-zhen ZHANG Jian-qin GUO Ya-ping MA En-bo Institute of Applied Biology Shanxi University Taiyuan 030006 P.R. China

Carboxylesterases （CarEs） from two field populations of the oriental migratory locust, Locusta migratoria manilensis （Meyen）, were examined to try to understand their contribution to malathion insensitivity. The CarEs activities in Wudi population （WD） were 1.75- and 1.50-fold significantly higher than those in Huangliu population （HL） when a-naphthyl acetate （a-NA） and [3-naphthyl acetate were used as substrates, respectively. Such elevated CarEs activities presented in the WD could be because of an increased staining intensity of the a-NA-hydrolyzing CarEs as shown on the nondenaturing polyacrylamide gel electrophoresis. Inhibition studies of CarEs using paraoxon and malaoxon indicated that CarE activities in the HL were more strongly inhibited than those in the WD. Furthermore, a 449-bp DNA fragment of CarE was obtained from L. migratoria manilensis. Hemiquantity reverse transcription-polymerase chain reaction analysis showed that CarE gene expression level in the WD was higher than that in the HL. The higher CarE activities and the increased CarE mRNA level in the WD appeared to be associated with decreased susceptibility to malathion in the WD due to the application of organophosphorus insecticides.

关键词： carboxylesterases enzyme kinetics enzyme inhibition RT-PCR Locusta migratoria manilensis

Comparisons of Properties of Acetylcholinesterase from Two Field-Collected Populations of Oxya chinensis Thunberg(Orthoptera:Acrididae)and the Role of Acetylcholinesterase in the Susceptibility to Malathion

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Agricultural Sciences in China 2005年第1期4卷 47-53页

作者： MA En-bo College of Life Science and Technology Shanxi University Taiyuan 030006 P.R.China

In this study, acetylcholinesterase (AChE) was extracted from two field-collected populations of Oxya chinensis (XinxiangCity, Henan Province and Changzhi City, Shanxi Province). AChE activities were decreased when concentrations of ATCincreased, showing a characteristic phenomenon of substrate inhibition at high concentration in both populations. Suchinhibition occurred at relatively low concentration for AChE from Xinxiang population but relatively high for AChE fromChangzhi population. The kinetic study showed that there were no significant differences between the two populations inthe Km values. The Km value in Changzhi population was only 1.09-fold higher than that in Xinxiang population. However,significant differences were observed between the two populations in Vmax values. The Vmax value in Changzhi populationwas 1.32-fold higher than that in Xinxiang population. The inhibition study in vitro showed that the AChE from bothpopulations exhibited similar rank order in sensitivity to inhibition by three OPs, as determined by comparison of theirbimolecular rate constants (ki), from the most potent inhibition to the least was chlopyrifos-oxon > paraoxon >demeton-s-methyl for AChE from the two populations and that the ki values in Xinxiang population were lower than those in Changzhipopulation. The I50 values of AChE from Xinxiang population were 4.84-, 2.66-, and 1.92-fold less sensitive to inhibition byparaoxon, chlopyrifos-oxon, and demeton-s-methyl. These results were consistent with the results in bioassay. It isinferred that AChE insensitivity to OP insecticides plays an important role in the differences of insusceptibility of Oxyachinensis to malathion between the two populations.

关键词： Acetylcholinesterase enzyme inhibition enzyme kinetics Oxya chinensis

Screening and Statistical Optimization of Physiochemical Parameters for the Production of Xylanases from Agro-Industrial Wastes

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Advances in enzyme Research 2016年第1期4卷 20-33页

作者： Mirza Baasit Ali Muhammad Irshad Zahid Anwar Mudassar Zafar Muhammad Imran Department of Biochemistry & Molecular Biology Faculty of Sciences University of Gujrat Gujrat Pakistan Institute of Biochemistry & Biotechnology University of Veterinary and Animal Sciences Lahore Pakistan

Xylanases are mostly produced through submerged fermentation;nonetheless solid-state fermentation has increased profound attention and consideration of scholars having high conversion level biomass to energy conservation. This study depicted the purification of xylanases and their possible utilization in industry. The present study was carried out to examine the culture influence of fungal strain Fomes fomentarius (F. fomentarius) using different agro-industrial residues (wheat straw, rice husk, sugarcane bagasse and siris pods). F. fomentarius showed maximum enzyme production after 72 h of fermentation, when grown on wheat straw in solid state fermentation process while maximum activity showed on pH 6.0 at 30°C. The other parameters optimized by statistical design (RSM) showed maximum xylanase activity (146 ± 8 IU/mL) at 65% moisture content, 4 mL inoculums size, 175 mg Ammonium sulphate, 200 mg Calcium carbonate and 1.4 grams of glucose. Xylanase was salted out at 60% ammonium sulphate concentration and enzyme was further purified by Sephadex G-100 gel filtration chromatography with 2.2 fold increase in activity. The purified xylanase from F. fomentarius had optimum pH 6.0 and 40°C. Xylanase showed higher specificity for oat spelt xylan with kinetic constants Km 1.25 mg/mL and Vmax 54 mM/min. Xylanases have an industrial important enzyme used extensively in food, feed and paper industry.

关键词： Xylanases Wheat Straw enzyme kinetics F. fomentarius Siris Pods

Comparison of the inhibitory effects of DDPH on CYP2D and CYP3A in human and rat liver microsomes

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Comparison of the inhibitory effects of DDPH on CYP2D and CY...

第十三次全国临床药理学学术大会

作者： Yin-Song Zhu,Xin-Xia Liu,Hui Chen Institute of Clinical Pharmacology,Tongji Medical College,Huazhong University of Science and Technology, Wuhan 430030

Objective To compare the inhibitory effects of DDPH(propranolol hydrochloride) on CYP2D and CYP3A in human liver microsomes(HLM) and rat liver microsomes(RLM),Dextromethorphan(DEX) O-demethylation and midazolam(MDZ) hydroxylation reaction were used to evaluate the enzyme activities of CYP2D and CYP3A respectively,and the Michaelis-Menten parameters(K,V) were determined. Methods To evaluate the kinetics constant and investigate the inhibitory effects of DDPH on CYP2D,DEX was concomitantly added at final concentrations of 4,5,10 and 20 uM with at the absence or presence of different concentrations of DDPH in the HLM or *** CYP3A-mediated reaction in both HLM and RLM,the effects of DDPH on MDZ hydroxylation were studied at MDZ concentrations of 2,4,8 and 16uM,and DDPH concentrations of 0-10μ*** O- demethylation yielded to dextrorphan were assayed by HPLC with fluorescence detector and MDZ metabolized to 1-hydroxylation midazolam(1-OH MDZ) and 4-hydroxylation midazolam(4-OH MDZ) were simultaneously analysed by HPLC with ultraviolet ***-Menten enzyme parameters(K and V) and the inhibition constants(K) and mode of inhibition for DDPH were evaluated with the Sigma Plot enzyme kinetics module for windows version11.0. Results The apparent intrinsic clearance(CL,calculated as V/K) of DEX O- demethylase was about 13-fold higher in the RLM than that in the HLM(6.19 vs 0.468μL/min/mg),due to a 4.2-fold lower K(23.9 vs 100.5 uM) and 3-fold higher V(0.148 vs 0.047 nmol/min/mg).DDPH strongly inhibited CYP2D-mediated reactions of DEX O- demethylation with the value of K 12.6-fold lower in the HLM than the RLM(0.23±0.03 vs 2.89±0.26 uM).The model of inhibition was noncompetitive in the human and competitive in rat liver *** Michaelis-Menten kinetic parameters are as follows:for 1-OH MDZ,V=0.208±0.006 and 0.620±0.026 nmol/min/mg and K= 1.54±0.22 and 3.59±0.44μM in the HLM and RLM,respectively;for 4-OH MDZ,the values were V=0.101±0.019 and 0.620±0.02

关键词： DDPH CYP2D CYP3A enzyme kinetics

Comparison ofalternative oxidaseactivitiesbetween Trypanosoma brucei,Sauromatumguttatum and Arabidopsis thaliana

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Comparison ofalternative oxidaseactivitiesbetween Trypanosom...

2018全国植物生物学大会

作者： Fei Xu Anthony L.Moore Applied Biotechnology Center Wuhan Institute of Bioengineering School of Life Sciences University of Sussex

The alternative oxidase(AOX) is a non-protonmotiveubiquinol oxidase which mediates the cyanide-resistant respiration and catalyzes the reduction of O to H O(Moore et al.,2013).AOX does not contribute to energy conservation and therefore has caused much debate about its function inliving ***,a broad distribution of the AOX has been found in protists,fungi,microsporidian parasites and animals(Williams et al.,2010).Interestingly,it should be noted that the respiratory activity of the blood parasite Trypanosoma brucei relies solely on the AOX(also named as TAO),while in thermogenic plants(e.g.,Sauromatumguttatum),SgAOX is responsible for heat *** non-thermogenic species(e.g.,Arabidopsis thaliana),AtAOXs play important roles in energy homeostasis and protection against oxidative ***,the activities of AOXs are varied,although the amino acids surrounding the quinol binding site are extremely well ***,it is important to understand what factors affect the activities of AOXs?Recently,the TAO,SgAOX and AtAOX1 a were expressed in the ***(FN102 heme-deficient strain) and the activities were compared with different *** showed that TAO has the highest affinity forubquinol,followed by the AtAOXlaand the *** kinetics of ubiquinol-1 oxidation by purified TAO,SgAOX and AtAOXla showed that Vof these proteins were 340,21 and 64 μmol QH minmg protein,***,SgAOX and AtAOX1 a exhibited 1.5-fold and 6-fold increase in the activity following the addition of 10 mM *** activity of AtAOXla was also improved by 5 mMglyoxylate(6-fold) and 10 mM oxaloacetate(3.5-fold).Additionally,the inhibitory efficacy by different compounds(AF,AC,CB,CD,n-OG and SHAM) showed that AF was the best inhibitor for TAO,whereas CB was the most effective inhibitor against SgAOX and *** exhibited lowest inhibitory efficacy against TAO,SgAOX and *** findings indicate that the metabolic flexibility that t

关键词： alternative oxidase enzyme kinetics protein purification

Biomimetic Natural enzyme with Peptide-modified Gold Nanaoparticles

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Biomimetic Natural Enzyme with Peptide-modified Gold Nanaopa...

第十一届中国酶工程学术研讨会

作者： Xin Jiang Junrong Zhang Siqi Lin Yi Guo 徐力 Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education Jilin University

Selenopeptide(Sec-Arg-Gly-Asp-Cys,URGDC) and cysteamine-cofunctionalized gold nanoparticles monolayer protected cluster(MPC),catalyzes the reaction of H O by GSH,exhibiting Glutathione peroxidase(GPx)-like *** nanozyme was constructed through two self-assemble steps:First,URGDC was conjugated to AuNPs,forming a multivalent catalyst(MPC 1);second,the positively charged cysteamine was subsequently employed to optimize the enzyme activity by regulating the surface chemistry of gold nanoparticles(MPC 2).The systematical study of the catalytic capability showed that the Nanozyme catalyzed reaction exhibits saturation kinetics:the reactive rate data complied with the Michaelis-Menten model of enzyme kinetics,and the GPx activity of MPC land MPC 2 is 5.05 and 7.21 U/umol,about 14 and 20 times of that of free *** kinetic analysis indicated that the catalytic mechanism of free peptide is ping-pong mechanism,while it is the ordered mechanism for nanozyme(MPC 1,MPC 2).And the catalytic constant K/K of both GSH and H O are one order of magnitude higher than that of free *** manifested that gold nanoparticle as a scaffold excels in limiting the mobility and constraining conformation of URGDC,and the multivalent selenopeptide act cooperatively in the catalysis *** surface/interface regulationof gold nanoparticles facilitates the recognition and binding of *** rational design of nanozyme greatly improves and amplifies the catalytic activity of ’active unit’ *** work provides an alternative strategy to establish GPx mimic and new insights regarding the surface chemistry of AuNPs as a nanozyme.

关键词： Nanotechnology Nanozyme Self-assembled monolayer(SAM) Glutathione peroxidase(GPx) mimic Bioactive peptide Gold nanoparticles enzyme kinetics