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1.
利用启动子探钍型载体pSUPV4直接在大肠杆菌细胞中克隆到多个来自白腐丝状真菌-黄孢平革菌(Phanerochaete chrtysosporium)基因2子片段。这些基因启动子片段能在大肠杆菌细胞中启动重卡那霉素抗性基因的表达,不同片段赋予宿主细胞以不同的卡那霉素抗性水平,最高的可达1000μg/mL,最低的则为50μg/mL。  相似文献   

2.
用大肠杆菌(Escherichiacoli)启动子探针型载体pSUPV1从环状芽胞杆菌(Eacilluaeirculansc-2)基因组中分离的启动子片段BC6能使无启动子的卡那霉素抗性基因恢复活性,并在大肠杆菌中获得高效表达(卡那霉素抗性高达1200μg/mL).当用限制酶XbaⅠ去除其5′-端1.2kb片段(命名为Xb片段)后,3′-端片段仍能启动Kan ̄r基因表达,其抗性水平降至400μg/mL但当1.2kb片段反向插回原有位置时,其抗性水平降至600μg/mL.将Xb片段正向插入另一重组质粒pBC3中融合的Kan ̄r基因启动子的上游时,卡那霉素抗性由200μg/mL上升至1000μg/mL.当Xb片段反向插入时,Kan ̄r基因的表达却明显受到抑制,降为100μg/mL.这说明Xb片段具有正向增强而反向衰减Kan ̄r基因表达的能力.用BC6片段的两个亚克隆片段与c-2菌株总DNA分别作Southern杂交时,结果显示3′-端片段以单拷贝形式存在于基因组中,而Xb片段则以多拷贝形式散布其中.由此推断Xb片段并非一定伴随该基因启动子存在.  相似文献   

3.
用大肠杆菌启动子探针型载体pSUPV1从环状芽胞杆菌基因组中分离的启动子片段BC6能使无启动子的卡那霉素抗性基因恢复活性,并在大肠杆菌中获得高效表达。当用限制酶XbaI去除其5’-端1.2kb片段后,3’-端片段仍能启动Kan’基因表达,其抗性水平降至400μg/mL,但当1.2kb片段反向回原有位置时,其抗性水平降至600μg/mL。将Xb片段正向插入另一重组质粒pBC3中融合的Kan’adld  相似文献   

4.
用来自大肠杆菌的潮霉素B磷酸转移酶基因(hygr)作为遗传标记构建了启动子探针型载体pSUPV8,该基因的转录和翻译起始区以及5’-端编码区两个密码子均被除去,载体骨架为大肠杆菌质粒pUGV2,该标记基因的终止子来自Phanerchaetecysosporium的LIP6基因  相似文献   

5.
利用启动子探针型质粒pKK232-8从卡介苗染色体DAN的BamHI酶切片段中克隆到4个具启动功能的DNA片段,测定各重组子对氯霉素(Cm)的抗性,其中含3.3Kb外源片段的重组质粒pBCG2大肠杆菌转化子在LM培养基上对Cm抗性可达170×10-6g/mL,作了该片段的限制性酶切图谱.对pBCG2利用SalⅠ位点,亚克隆出4种部分重叠的具启动功能的DNA片段,这4种重组质粒分别命名为pBCG2-1,pBCG2-2,pBCG2-6和pBCG2-8,并分析了其中插入片段的大小及其转化子对Cm的抗性.将pBCG2-2的SalⅠ外源片段插入到分枝杆菌启动子探针型穿梭质粒pEQ3,获得一个可在卡介苗中表达lacZ基因的重组子pEB22.斑点杂交实验证明,具有启动功能的DNA片段来源于卡介苗的染色体DNA.结果表明克隆到一个对大肠杆菌和卡介苗均具启动子活性的DNA片段  相似文献   

6.
环状芽胞杆菌(Bacilluscirculans)总DNA经Sau3AI酶切后插入到启动子探针型载体pSUPV1的BamHI位点,转化大肠杆菌后,在卡那霉素的平板上筛选到50个抗性菌落。从随机挑取的29个抗住菌落所分离到的质粒DNA经限制酶切和琼脂糖凝胶电泳后表明,各质粒均有DNA插入片段,对29个样品进行卡那霉素抗性试验显示,抗性最高的可超过1000μg/mL这表明来自环状芽胞杆菌的某些基因启动子能在大肠杆菌中十分有效地启动基因表达,选取两个最大的克隆DNA片段BC3和BC6作为探针与B.circulansc-2.总DNA作Southern杂交,均获得杂交带。斑点杂交结果表明,这两个DNA片段来自不同的基因启动子。对BC6和BC3分别进行了限制酶谱分析,并绘制了限制酶图。  相似文献   

7.
恶臭假单胞菌萘质粒ⅠNL基因的克隆及酶切图谱   总被引:1,自引:0,他引:1  
恶臭假单胞菌(PseudomonasputidaG7)携带的质粒NAH7,经限制性内切酶EcoRI切割后,产生含有萘降解酶全部基因(24,6kb)的片段,此片段插入到载体pUC119的多克隆位点,构成了pKAO质粒,此质粒经HpaI,EcoRI酶切获得的5.1kb片段亚屯隆到pUC119中,衍生出pNN1质粒,绘制出内切酶图谱。从pNNI质粒上切下含目的基因nahI、nahN和nahL的kpnI-kpnI片段(2.3kb).正向插入载体BluescriptⅡSK+中获得重组质粒pNN2,反向插入为pNN3,将其转化到大肠杆菌XL1-Blue中,目的基因得以大量增殖。  相似文献   

8.
环状芽孢杆菌中具有强启动活性DNA片段的结构与功能分析   总被引:1,自引:1,他引:0  
作者曾用启动子探针型载体pSUPV1从环状芽孢杆菌C-2菌株(BacilluscirculansC-2)中克隆到一个具有强启动功能的2.4kb片段BC6.对该片段作作的进一步缺夫分析表明,其3’端约0.7kb片段具有单独的基因启动子功能,序列分析表明BC6片段3′端有典型的原核生物的基因启动子结构,现有BC6的5’端的1.2kbXhiI片段的重组于pBR322的EcoRI位点,观察其对两侧具有不同  相似文献   

9.
将3.4kb的多能硫杆菌1,-5二磷酸核酮糖羧化酶/加氧酶基因片估亚克隆到启动子探测质粒载体pKL6的HindⅢ位点,该基因片段能够启动pKL6的lac基因的表达,说明3.4kb的rbcL-rbcS基因带有自己的启动子。  相似文献   

10.
将3.4kb的多能硫杆菌1,5-二磷酸核酮糖羧化酶/加氧酶基因(rbcL-rbcS)片段亚克隆到启动子探测质粒载体pKL6的HindⅢ位点,该基因片段能够启动pKL6的lac基因的表达,说明3.4kb的rbcL-rbcS基因带有自己的启动子.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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