检索结果-南通市图书馆

Identification and Characterization of hmr19 Gene Encoding a Multidrug Resistance Efflux Protein from Streptomyces hygroscopicus *** Strain 10-22

引用

Acta Biochimica et Biophysica Sinica 2004年第8期36卷 519-528页

作者： Lei QIN , Heng-An WANG1 , Zhong-Qin WU, Xiao-Feng ZHANG, Mei-Lei JIN,Zi-Xin DENG2, and Guo-Ping ZHAOshanghaiResearch Center of Biotechnology, shanghai Institute for Biological Sciences, Chinese Academy of Sciences,graduate school of the Chinese Academy of Sciences, shanghai 20023., china 1school of Agriculture and Biology, shanghai Jiaotong University, shanghai 201101, china 2school of Life Science and Biotechnology, shanghai Jiaotong University, shanghai 200030, china shanghaiResearch Center of Biotechnology Shanghai Institute for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences school of Agriculture and Biology Shanghai Jiaotong University

The hmr19 gene was cloned from Streptomyces hygroscopicus subsp. yingchengensis strain 10- 22, a bacterium strain producing agricultural antibiotics. Sequence similarity comparison indicates that hmr19 gene may encode a predicted protein with 14 putative transmembrane α-helical spanners, belonging to the drug:H+ antiporter-2 family of the major facilitator superfamily. The expression of hmr19 in the mycelium of strain 10-22 was detected by Western blotting analysis. Gene replacement technology was employed to construct an hmr19 disruption mutant. The growth inhibition test against different antibiotics indicated that the mutant strain was 5–20 fold more susceptible to tetracycline, vancomycin and mitomycin C than the parental wild type strain. The mutant took up tetracycline much faster and accumulated more antibiotics than the wild type strain 10-22. While with the addition of an energy uncoupler, carbonyl cyanide m- chlorophenylhydrazone, the characteristics of the accumulation of [3H]tetracycline in these two strains were almost the same. It was thus concluded that hmr19 encoded a multidrug resistance efflux protein.

关键词： multidrug resistance (MDR) gene replacement (knockout) Streptomyces Streptomyces hygroscopicus subsp. yingchengensis strain 10-22

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A New Measurement Method for Unbalanced Moments in a Two-axis Gimbaled Seeker

引用

Chinese Journal of Aeronautics 2010年第1期23卷 117-122页

作者： Yu Shuang,Zhao Yanzheng school of Mechanical Engineering,shanghai Jiaotong University,shanghai 200240,china [a] school of Mechanical Engineering Shanghai Jiaotong University Shanghai 200240 China

This article presents a novel method to measure unbalanced moments in a two-axis gimbaled seeker commonly believed to seviously influence the tracking accuracy and stabilizing capability. This method enables individual measurement of unbalanced moments, and judgment of the seeker＇ s status-balanced or not. Furthermore, an instrument is designed based on this method and calibrated. The effectiveness of the proposed method is validated through a simulation. The experimental results show a satisfied level of accuracy the measurements have. This work forms a basis for the further development of a more stabilized gimbaled seeker with less induced vibration and consumed power.

关键词： gimbaled seeker weight sensors measurement unbalanced

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

Optical and acoustic phonon modes confined in gallium phosphide nanoparticles

引用

Rare Metals 2010年第6期29卷 561-566页

作者： ZHANG Zhaochun and ZHANG Neng school of Material Science and Engineering,shanghai University,shanghai 200072,china school of Material Science and Engineering Shanghai University Shanghai China

The main aim of this paper is to discuss the confinement effects on the optical and acoustic phonon vibrational modes in gallium phosphide（GaP） nanoparticles（cylindric grain）.The Raman scattering from the GaP nanoparticles was *** was found that the red-shifts of the longitudinal optical（LO） mode and transverse optical（TO） mode were 15 cm？1 and 13.8 cm？1,*** is generally accepted that the red-shifts of the optical phonon modes are due to the presence of smaller nanosized particles（～1.2 nm） acting as the nanoclustered building blocks of the GaP *** the low frequency Raman spectrum,a set of Stokes lines with almost the same spacing was clearly *** scattering feature originates from the discrete phonon density of states of the nanoclustered building *** to Lamb＇s vibrational theory,the Raman shift wavenumbers of the spheroidal mode and torsional mode of the lowest energy surface modes for the nanoclustered building blocks were *** agreement can be achieved between the calculated results and the observed scattering *** results indicate that the corresponding Raman peaks are due to scattering from the localized acoustic phonons in the nanoclustered building blocks in the GaP nanoparticles.

关键词： spectroscopy phonon mode Raman scattering gallium phosphide nanoparticles confinement effects

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

Positive Charges on Lysine Residues of the Extrinsic 18 kDa Protein Are Important to Its Electrostatic Interaction with Spinach Photosystem Ⅱ Membranes

引用

Acta Biochimica et Biophysica Sinica 2005年第11期37卷 737-742页

作者： Jin-Peng GAO Zhen-Hua YONG Feng ZHANG Kang-Cheng RUAN Chun-He XU Gen-Yun CHEN Institute of Plant Physiology & Ecology.shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,shanghai 2.0032.china Laboratory of Proteomics,Institute of Biochemistry and Cell Biology,shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,shanghai 200031,china College of Sciences,Zhejiang University.Hangzhou 310029,china graduate school of the Chinese Academy of Sciences,shanghai 2.0032.china Institute of Plant Physiology & Ecology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200032 China graduate school of the Chinese Academy of Sciencesshanghai 2.0032 China College of Sciences Zhejiang UniversityHangzhou 310029 China Laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200031 China

To determine the contribution of charged amino acids to binding with the photosystem Ⅱcomplex(PSⅡ),the amino or carboxyl groups of the extrinsic 18 kDa protein were modified with N-succinimidyl propionate(NSP)or glycine methyl ester(GME)in the presence of a water-soluble carbodiimide,*** on isoelectric point shift,4-10 and 10-14 amino groups were modified in the presence of2 and 4 mM NSP,***,3-4 carboxyl groups were modified by reaction with *** of negatively charged carboxyl groups with GME did not alter the binding activity of theextrinsic 18 kDa ***,the NSP-modified 18 kDa protein,in which the positively charged aminogroups had been modified to uncharged methyl esters,failed to bind with the PSⅡ membrane in the presenceof the extrinsic 23.kDa *** defect can not be attributed to structural or conformational alterationsimposed by chemical modification,as the fluorescence and circular dichroism spectra among native,GME-and NSP-modified extrinsic 18 kDa proteins were ***,we have concluded that the positive chargesof lysyl residues in the extrinsic 18 kDa protein are important for its interaction with PSⅡ membranes in thepresence of the extrinsic 23.kDa ***,it was found that the negative charges of carboxylgroups of this protein did not participate in binding with the extrinsic 23.kDa protein associated with PSⅡmembranes.

关键词： extrinsic 18 kDa protein circular dichroism electrostatic interaction chemical modification

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Influence of Mo on the microstructure and mechanical properties of TiC-based cermets

引用

Rare Metals 2010年第4期29卷 346-350页

作者： WANG Xingqing,HE Xiaoxiang,and GUO Hailiang school of Materials Science and Engineering,shanghai University,shanghai 200072,china school of Materials Science and Engineering Shanghai University Shanghai China

The microstructures and mechanics properties of TiC-based cermets composed of TiC, WC, Ni, Co, Mo, and Cr3C2 were investigated. The results show that Mo has a great effect on the sintering densification, microstructures, and mechanical properties. The microstructures and distribution of Mo and Ti in the TiC-based cermets were analyzed. It was indicated that a new phase with Ti, Mo, W, and C was formed on the rim of （Ti,W）C grains by means of an addition of Mo into the TiC-based cermets. The new phase with a surrounding structure was of great aid to improve the wettability of the liquid phase on the solid phase surface of TiC, decrease the porosity and refine the grains of the hard phase, which gave rise to the increase in strength and hardness. The properties of the TiC-based cermets could be further improved to some extent by adding WC, Cr2C3, and Co.

关键词： TiC-based cermets Mo effect sintering densification microstructure mechanical properties

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

A Resistivity Gradient Piezoelectric FGM Actuator

引用

Journal of Materials Science & Technology 2000年第4期16卷 383-386页

作者： S. U.Adikary and Zhongyan MENG (school of Materials Science and Engineering, shanghai University, shanghai 201800, china) Dengren JIN (school of Materials Science and Engineering, shanghai Jiaotong University, shanghai 200030, china) school of Materials Science and Engineering Shanghai University Shanghai 201800 China school of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200030 China

A resistivity gradient actuator based on lead zirconate titanate ceramics was successfully developed and the bending deflections up to 140 μm were obtained. The actuator material was a matrix of PZT ceramic into which smooth gradient of piezoelectric activity was introduced. The application of an electric field then causes the actuator to bend due to differential strains induced by the piezoelectric effect. The resistivity gradient of the actuator was achieved by doping PZT with suitable donor and acceptor dopants. PZT powder was modified and synthesized by using two stage powder fabrication method. The actuator was fabricated by uniaxial pressing followedby isostatic pressing with two layers of different resistivities.

关键词： PZT FGM

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

Sorption of a triazol derivative by soils: importance of surface acidity

引用

Journal of Environmental Sciences 2003年第3期15卷 383-387页

作者： WU De-yi (school of Environmental Science and Engineering, shanghai Jiaotong University, shanghai 200240, china.) school of Environmental Science and Engineering Shanghai Jiaotong University Shanghai 200240 China

The sorption of a triazol derivative, 1-(4-chlorophenyl)- 4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)penten-3-ol with a common name of S3307D, on fifteen soils and three H_2O_2-treated soils was investigated. The sorption isotherm for each untreated and treated soil was non-linear, and was best fitted to Freundlich sorption equation. Soils containing high amount of clay content or organic matter or both sorbed much higher amounts of the chemical than soils that had low contents of these soil constituents. H_2O_2-treated soils showed considerable sorptive affinity for S3307D. It was concluded that both organic matter and mineral fraction in natural soils contributed to the sorption of the basic compound. Sorption by the H_2O_2 treated soils increased as suspension pH decreased, but all suspension pHs exceeded the pKa of the compound by more than two units. This implies that organic base protonation can occur on surfaces of soil components, and surface acidity (exchangeable acidity ) is important in sorption process of the organic base rather than suspension pH.

关键词： sorption organic base soil surface acidity

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

The cDNA and Genomic DNA Organization of a Novel Toxin SHT-I from Spider Ornithoctonus huwena

引用

Acta Biochimica et Biophysica Sinica 2004年第10期36卷 656-660页

作者： Peng QIAO, Xiao-Pan ZUO, Zhi-Fang CHAI, and Yong-Hua JI* Institute of Physiology, shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, graduate school of the Chinese Academy of Sciences, shanghai 200031, china Institute of Physiology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

In present study the full-length cDNA of a novel toxin from the venom gland of spider Ornithoctonus huwena, named as SHT-I, has been cloned using the strategy of rapid amplification of cDNA ends, and then the whole genomic sequence of SHT-I (Selenocosmia huwena toxin-I) was determined using sequence-specific primers synthesized based on the acquired 3’ and 5’ ends of SHT-I cDNA sequence. It is unexpectedly found that intron was lacking in the genomic sequence of SHT-I. The result might evoke an interesting question whether the gene code of inhibitor cystine-knot peptides from spider venom is distinct from that of those known toxic peptides of scorpion and cone snail.

关键词： Ornithoctonus huwena spider cDNA genomic DNA peptide toxin ICK motif

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A NOTE ON THE CONSISTENCY OF LS ESTIMATES IN LINEAR MODELS

引用

Chinese Annals of Mathematics,Series B 2001年第4期22卷 471-474页

作者： CHEN XIRU The graduate school at Beijing, University of Science and Technology of china, Beijing 100039, china. The graduate school at Beijing University of Science and Technology of China Beijing 100039 China

It is well known that when the random errors are iid. with finite variance, the week and the strong consiStency of LS estimate of multiple regression coefficients are equivalent. This note, by constructing a counter-example, shows that this equivalence no longer holds true in case that the random errors possess only the r-th moment with 1≤5 T ＜ 2.

关键词： Linear regression model Consistency LS estimate

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

Approximate solutions to infinite dimensional LQ problems over infinite time horizon

引用

Science china Mathematics 2006年第7期49卷 865-876页

作者： PAN Liping, ZHANG Xu & CHEN Qihong school of Mathematical Sciences, Fudan University, shanghai 200433, china school of Mathematics, Sichuan University, Chengdu 610064, china Department of Applied Mathematics, shanghai University of Finance & Economics, shanghai 200433, china school of Mathematical Sciences Fudan University Shanghai 200433 China school of Mathematics Sichuan University Chengdu 610064 China Department of Applied Mathematics Shanghai University of Finance & Economics Shanghai 200433 China

This paper is addressed to develop an approximate method to solve a class of infinite dimensional LQ optimal regulator problems over infinite time horizon. Our algorithm is based on a construction of approximate solutions which solve some finite dimensional LQ optimal regulator problems over finite time horizon, and it is shown that these approximate solutions converge strongly to the desired solution in the double limit sense.

关键词： approximate solution LQ problem infinite dimensional infinite time hori-

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

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：