检索结果-南通市图书馆

Effect of mutations on acetohydroxyacid synthase(AHAS)function in Cyperus difformis L.

Journal of Integrative Agriculture 2024年第1期23卷 177-186页

作者： Xiaotong Guo Xiangju Li Zheng Li Licun Peng jingchao chen Haiyan Yu Hailan Cui State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193China College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193China

Cyperus difformis *** a troublesome weed in paddy fields and has attracted attention due to its resistance to acetohydroxyacid synthase(AHAS)*** was found that the amino acid mutation in AHAS was the primary cause for the resistance of Cyperus ***,the effect of different mutations on AHAS function is not clear in Cyperus *** confirm the effect of mutations on AHAS function,six biotypes were collected,including Pro197Arg,Pro197Ser,Pro197Leu,Asp376Glu,Trp574Leu and wild type,from Hunan,Anhui,Jiangxi and Jiangsu provinces,China and the function of AHAS was *** AHAS in vitro inhibition assay results indicated that the mutations decreased the sensitivity of AHAS to pyrazosulfuron-ethyl,in which the I_(50)(the half maximal inhibitory concentration)of wild type AHAS was 0.04μmol L^(-1)and Asp376Glu,Pro197Leu,Pro197Arg,Pro197Ser and Trp574Leu mutations were 3.98,11.50,40.38,38.19 and 311.43μmol L^(-1),*** the determination of enzyme kinetics parameters,the Km and the maximum reaction velocity(Vmax)of the wild type were 5.18 mmol L^(-1)and 0.12 nmol mg^(-1)min^(-1),respectively,and the Km values of AHAS with Asp376Glu,Trp574Leu,Pro197Leu and Pro197Ser mutations were 0.38-0.93 times of the wild *** Km value of the Pro197Arg mutation was 1.14times of the wild type,and the Vmax values of the five mutations were 1.17-3.33-fold compared to the wild *** was found that the mutations increased the affinity of AHAS to the substrate,except for the Pro197Arg *** a concentration of 0.0032-100 mmol L^(-1)branched-chain amino acids(BCAAs),the sensitivity of the other four mutant AHAS biotypes to feedback inhibition decreased,except for the Pro197Arg *** study elucidated the effect of different mutations on AHAS function in Cyperus difformis and provided ideas for further study of resistance development.

关键词： acetohydroxyacid synthase(AHAS) mutation enzyme function Cyperus difformis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Interface structure of Ag(111)/SnO_(2)(200)composite material studied by density functional theory

引用

Science China(Technological Sciences) 2009年第5期52卷 1258-1263页

作者： FENG Jing chen jingchao XIAO Bing YU Jie Key Laboratory of Advanced Materials of Precious-Nonferrous Metals Ministry of Education of Chinaand Key Laboratory of Advanced Materials of Yunnan ProvinceKunming University of Science and TechnologyKunming 650093China School of Materials Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

Electric contact material of Ag/SnO2 was successfully synthesized by in situ process *** in-terface structure was characterized by high-resolution transmission electron microscopy(HTEM) and simulated at atomic scale on *** mean-square displacements of atoms near the interface were calculated,and the results showed that near the interface both Ag side and SnO2 were mis-matched and this effect decays rapidly far from the *** inspecting the calculated density of states(DOS),we found that the electric-conductivity of this composite material was decreased because of the localized 4d and 2p electrons of Ag and O near the Fermi surface,*** density changed acutely across the interface,so that there was no extra compound precipitated.A mi-cro-electric field also formed in the whole material due to the interface structure,and this may affect the electron conduction and the related electric-conductivity of the *** is found that the interface cohesive energy of Ag(111)/SnO2(200) was-3.50 J/m2,which is higher than the experimental results.

关键词： electric contact material reactive synthesis interface energy structure relaxation electron structure Ab initio

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

南繁基地牛筋草对草甘膦的抗药性研究

引用

植物保护 2024年第3期50卷 131-136页

作者：陈景超崔海兰于海燕李志玲李香菊中国农业科学院植物保护研究所植物病虫害综合治理全国重点实验室北京100193

牛筋草是一年生禾本科恶性杂草,在我国黄淮海流域及长江以南地区的农田危害严重。草甘膦是一种优良的非选择性除草剂,随着生物育种产业化的推进,草甘膦会逐步在玉米、大豆等作物田登记应用。育种基地抗草甘膦杂草的产生是其快速传播的... 详细信息

牛筋草是一年生禾本科恶性杂草,在我国黄淮海流域及长江以南地区的农田危害严重。草甘膦是一种优良的非选择性除草剂,随着生物育种产业化的推进,草甘膦会逐步在玉米、大豆等作物田登记应用。育种基地抗草甘膦杂草的产生是其快速传播的潜在因素。为明确三亚一育种基地牛筋草种群对草甘膦的敏感性,本研究利用生物测定、分子生物学等方法检测了待测种群的抗性水平,并分析了可能的分子机制。结果发现,草甘膦对牛筋草种群的生长抑制中量为2053.0 g/hm^(2)(有效成分用量),抗性指数(RI)为5.0;靶标基因EPSPS的保守区域无突变,但相对表达量是敏感种群的47.4倍;抗性植株中EPSPS蛋白的浓度是敏感植株的17.1倍。以上结果表明,该牛筋草种群对草甘膦产生了中等水平抗性,靶标基因过量表达是其抗性机制之一。

关键词：牛筋草草甘膦抗药性传播

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

牛筋草PFK蛋白多克隆抗体的制备及其在草甘膦抗性鉴定上的应用

引用

植物保护 2024年第5期50卷 199-204页

作者：陈景超李志玲崔海兰于海燕马宇菲李香菊中国农业科学院植物保护研究所植物病虫害综合治理全国重点实验室北京100193 集宁师范学院乌兰察布012000

抗草甘膦牛筋草中磷酸果糖激酶(PFK)与靶标酶5-烯醇式丙酮酰莽草酸-3-磷酸合酶(EPSPS)的含量存在线性关系,是牛筋草对草甘膦产生抗性的指示蛋白之一。为实现抗草甘膦牛筋草的快速鉴定,本研究克隆了牛筋草PFK全长基因,构建原核表达载体,... 详细信息

抗草甘膦牛筋草中磷酸果糖激酶(PFK)与靶标酶5-烯醇式丙酮酰莽草酸-3-磷酸合酶(EPSPS)的含量存在线性关系,是牛筋草对草甘膦产生抗性的指示蛋白之一。为实现抗草甘膦牛筋草的快速鉴定,本研究克隆了牛筋草PFK全长基因,构建原核表达载体,并免疫大兔最终获得多克隆抗体,进一步对抗体的特异性和灵敏性进行了检测,并用该抗体对抗性牛筋草进行了检测鉴定。结果发现,PFK基因全长1656 bp,编码551个氨基酸,该基因的原核表达载体pGEX-4T-1-PFK经诱导后表达的蛋白大小为45 kD,蛋白纯化后浓度为3.5 mg/mL。制备的多克隆抗体能特异地识别牛筋草PFK蛋白,稀释512000倍后仍可检测到抗原,并能够准确鉴定PFK不同表达量的抗性牛筋草。结果表明:本研究制备的PFK多克隆抗体具有特异性强、灵敏度高的特点,可鉴定EPSPS过表达的抗草甘膦牛筋草,这为牛筋草对草甘膦抗药性的快速鉴定提供了实用工具。

关键词：磷酸果糖激酶牛筋草多克隆抗体草甘膦抗药性

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

AgOTf-Catalyzed Tandem Reaction of Oxabenzonorborna- dienes with Arylacetylenes

引用

Chinese Journal of Chemistry 2015年第10期33卷 1115-1118页

作者： Yongyun Zhou Shanshan Liu Hualei chen jingchao chen Weiqing Sun Sifeng Li Qingjing Yang Baomin Fan YMU-HKBU Joint Laboratory of Traditional Natural Medicine Yunnan Minzu University Kunming Yunnan 650500 China

A tandem isomerization/hydroarylation reaction of oxabenzonorbomadienes and arylacetylenes was realized by using AgOTf as catalyst. 1,1-Diarylethylenes could be easily generated as products in moderate to good yields ... 详细信息

关键词： silver tandem reaction catalyze 1,1-diarylethylene oxabenzonorbomadiene

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Simulation of Mechanical Properties of Nano-scale Cu/FeS Composite

引用

Journal of Materials Science & Technology 2010年第4期26卷 337-343页

作者： Zhenjun Hong jingchao chen Jing Feng Yeping Du Jie Yu Lijuan Zhang Shuzhen Wu Futai Xu Key Laboratory of Advanced Materials of Precious-Nonferrous Metals Education Ministry of China Kunming University of Science and Technology Kunming 650093 China Faculty of Materials and Metallurgical Engineering Kunming University of Science and Technology Kunming 650093 China

The mechanical properties of nano-scale Cu/FeS composite were simulated by molecular dynamics （MD） simulation in this paper. Through the analysis on the stress-strain curves, the results of MD simulation were in good agreement with mechanisms of macroscopic deformation. When the size of particles was smaller than a certain value, the relationship between yield strength and size, which was different from the large size crystals abided by the contrary Hall-Petch relationship. Based on the discussion of nano-scale Cu/FeS composite, some interesting conclusions were obtained. For example, the ＂S＂ type curves were discovered in stress-strain curves and the anisotropy of FeS was very evident when the exposures of reinforcing phase （FeS） were different and so on. The basic theories and calculations of the composite that contains nano-scale particles were discussed. At the same time, a new modeling building method of composites, which was close to actual experiences, were considered in this paper.

关键词： Nano-scale composite Mechanical properties Molecular dynamics simulation Elastic modulus Strain rigidity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

偕二氟烯丙基硅的光催化合成

引用

云南大学学报（自然科学版） 2024年第2期46卷 327-337页

作者：李智杨春晖温万柳孙蔚青和振秀陈景超樊保敏云南民族大学民族医药学院云南昆明650500 云南民族大学化学与环境学院云南昆明650500

烯丙基硅化合物是合成创新材料单体或医药中间体的重要化合物和合成中间体.文章报道了4CzIPN作为有机光催化剂催化的硅基羧酸的脱羧偕二氟烯丙基化反应.该反应使用在空气中能够稳定存在且容易大量合成的硅酸作为硅源,在温和的条件下高... 详细信息

烯丙基硅化合物是合成创新材料单体或医药中间体的重要化合物和合成中间体.文章报道了4CzIPN作为有机光催化剂催化的硅基羧酸的脱羧偕二氟烯丙基化反应.该反应使用在空气中能够稳定存在且容易大量合成的硅酸作为硅源,在温和的条件下高效合成偕二氟烯丙基硅化合物.结果为制备具有良好官能团相容性的偕二氟烯丙基硅化合物提供了一种快速、简单、经济的光化学合成方法.

关键词：烯丙基硅基化偕二氟烯丙基偕二氟烯烃烯丙基硅烷光催化

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Metal-Free Visible-Light-Induced Atom-Transfer Radical Addition Reaction of Alkenes/Alkynes with ICH_(2)CN

引用

Chinese Journal of Chemistry 2022年第17期40卷 2040-2046页

作者： Chunxiang Pan Yunyan Meng Yao Deng Bingjie Zhou jingchao chen Zhenxiu He Weiqing Sun Ruhima Khan Baomin Fan Key Laboratory of Chemistry in Ethnic Medicinal Resources Yunnan Minzu UniversityYuehua StreetKunmingYunnan650500 China Key Laboratory of Advanced Synthetic Chemistry Yunnan Minzu UniversityYuehua StreetKunmingYunnan650500 China

New blue-light promoted methods for the addition of iodoacetonitrile(ICH_(2)CN)to alkene/alkynes have been *** reaction led to the formation of cyanoalkylated products when conjugated alkene/styrene was *** the case of alkynes and non-conjugated alkenes,iodoalkylation takes place furnishing the corresponding alkenyl iodides and alkyl iodides,***,trans-alkenyl iodides were obtained as the major product.A plausible reaction mechanism is also proposed.

关键词： Blue LED Photochemistry Alkenes Alkynes Cyanoalkylation Carboiodination

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Interface Structure of Ag/SnO_2 Nanocomposite Fabricated by Reactive Synthesis

引用

Journal of Materials Science & Technology 2010年第1期26卷 49-55页

作者： jingchao chen Jing Feng B. Xiao K.H. Zhang Y.P. Du Z.J. Hong R. Zhou Key Laboratory of Advanced Materials of Precious-Nonferrous Metals Education Ministry of China and Key Lab of Advanced Materials of Yunnan Province Kunming University of Science and Technology Kunming 650093 China State Key Laboratory of Mechanical Behavior of Materials School of Materials Science and Engineering Xi'an Jiaotong University Xi'an 710049 China

The electric contact material of Ag/SnO2 composite was achieved by reactive synthesis method. The compositions and microstructure of Ag/SnO2 composite were analyzed and characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and high-resolution electron microscopy （HRTEM）. The struc- tural feature was typical of the particle reinforced composites. The HRTEM images revealed that the observed Ag/SnO2 interface was absence of the precipitated phase and the lattice contrast across the interface was clear and sharp. The average particle size of SnO2 in composite was near 50 nm and it was well dispersed in spherical shape. The thermodynamic mechanism of reactive synthesis method was also discussed. The electronic density distribution analysis of the interface showed the charges of Ag atoms transmitted to 0 atoms and the conductivity of the material was also affected. No extra compounds expected such as AgxOy formed at interface. The distribution of electrons was of inequality near the interface which explained why the mechanical property of the metal/ceramic materials was improved but the machining property declined.

关键词： Metal-matrix composites Electric contact material Interface In situ

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

我国西瓜田草害发生及综合防控技术

引用

现代农药 2024年第3期23卷 1-7,50页

作者：李香菊陈景超黄兆峰崔海兰于海燕中国农业科学院植物保护研究所北京100193

杂草是西瓜田重要的有害生物之一,近年来西瓜田杂草危害呈加重趋势。初步调查发现我国西瓜田杂草137种,隶属34个科,在样方中出现频率5%以上的杂草87种,隶属26个科。西瓜移栽后20~30 d为杂草防治关键期。西瓜田登记的除草剂有效成分有7个... 详细信息

杂草是西瓜田重要的有害生物之一,近年来西瓜田杂草危害呈加重趋势。初步调查发现我国西瓜田杂草137种,隶属34个科,在样方中出现频率5%以上的杂草87种,隶属26个科。西瓜移栽后20~30 d为杂草防治关键期。西瓜田登记的除草剂有效成分有7个,其中,土壤处理剂精异丙甲草胺、异丙甲草胺、敌草胺、仲丁灵等对禾本科杂草防治效果较好,对大部分阔叶杂草防效差;茎叶处理剂精喹禾灵、高效氟吡甲禾灵、噁草酸等对禾本科杂草有效。西瓜田杂草防控应遵循良好种植规范下的综合治理策略(IPM),利用植物检疫、农作方法、生态调控等除草措施辅助除草剂科学使用,同时注重选育耐除草剂西瓜材料,保证西瓜高产、优质和安全生产。

关键词：西瓜杂草综合治理策略除草剂

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：