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1.
RATS1基因对人食管癌细胞c—myc基因表达的降调…   总被引:1,自引:0,他引:1  
将含有RATS1cDNA的真核表达载体pCDV1与含有neo抗性基因的表达载体pDOR-neo经Lipofectin法共转染人食管癌细胞系EC109细胞。结果发现:转染RATS1基因后的抗性克隆细胞生长受到抑制,形态发生明显改变,并且逐渐脱落死亡。经RT-PCR分析发现,转染后有RATS1基因表达的细胞克隆,c-myc基因表达降低,两者呈反向相关,即RATS1基因表达愈高,c-myc基因表达降低愈  相似文献   

2.
小鼠B7—1cDNA克隆,测序,表达及其抗瘤效应的初步探讨   总被引:4,自引:0,他引:4  
用反转录PCR的方法,从BALB/c小鼠脾细胞中扩增出B7-1cDNA后,插入pcDNA3质粒中构建成小鼠B7-1cDNA的真核表达载体pCD-mB7.1,经酶切鉴定和序列分析证实此表达载体中插入的B7-1cDNA的序列与献报道一致。  相似文献   

3.
目的:为用基因重组技术表达hCG避孕疫苗抗原,构建在酵母细胞中表达的重组质粒βhCG-pPIC9K,转化嗜甲醇酵母,方法:根据βhCG的cDNA序列设计两条引物,使上游带EcoRⅠ酶切位点,下游带NotⅠ酶切位点,以质粒βhCG-PBSKS为模板,进行PCR扩增反应;将所得的DNA片段经EcoRⅠ和NotⅠ双酶切后用T4连接酶与pPIC9K质粒进行连接,然后导入大肠杆菌DH5α,用PCR筛选阳性克  相似文献   

4.
应用PCR定点突变技术,分别扩增出-3位碱基是A或T的乙肝病毒核心抗原基因c1,c2,平端克隆到自行构建便于PCR产物克隆的通用载体pBlueoS中后,利用经PCR引物在c1及c2末端引入的酶切位点,切出c1,c2基因,构建出pX3-c1和pX3-c2.在Sf9细胞中瞬时表达c1,c2基因,乙肝核心抗原放免检测结果表明,两种形式的c基因的表达无明显差异.说明-3位是否为A对c基因在昆虫细胞中的表达量没有影响.  相似文献   

5.
根据国外报道的JEV(Japanese encephalitis virus)基因组全序列,针对JEV E基因5′端设计合成一对特异引物,以日本脑炎病毒内蒙古分离株M73-1RNA为模板,经RT-PCR扩增,获得366bp的JEV E基因cDNA片段。将此片段重组于质粒pUC19中,并转化大肠杆菌DH5α,经PCR扩增,酶切及序列分析,结果表明JEV M73-1 5′端126个核苷酸序列与JEV日  相似文献   

6.
红细胞生成素(EPO)在中国仓鼠卵巢细胞(CHO)中稳定表达   总被引:4,自引:0,他引:4  
将EPOcDNA分别插入真核表达质粒载体pSV2dhfr和pcDNA3的适当位点,用电脉冲法导入CHO细胞,用ELISA法检测EPO的表达量,用TF1细胞检测EPO表达产物的生物活性.结果表明,用pSV2dhfr作为载体,在抗MTX阳性细胞克隆中,获得了表达EPO(258ng/mL培养液)的CHO细胞株,并且表达产物具有生物活性.进一步的传代和冻存试验表明,所得细胞株表达EPO的水平不受传代和冻存的影响  相似文献   

7.
OA能诱发人神经母细胞瘤SK细胞进行编程死亡.死亡细胞缩小变圆,细胞质凝聚,DNA有控降解成约200bp左右的片段,且这一过程可由蛋白质合成抑制剂亚胺环己酮(CHX)抑制.将编码Bc1-2全长蛋白质的cDNA植入pXJ41neo载体中,使其表达由HCMV病毒启动子控制.形成的顺义(pBcl-2-S)及反义(pBcl-2-AS)表达质粒经转染导入SK细胞中获得稳定转染子,West-ern印迹表明顺义转染子表达较大量的26kdBc1-2蛋白,而反义转染子则不表达.增强表达的Bc1-2基因产物对OA引SK细胞编程死亡无抑制效应.  相似文献   

8.
丙型肝炎病毒核酸疫苗的研究   总被引:1,自引:0,他引:1  
从丙型肝炎病人的阳性血清中提取出丙型肝炎病毒RNA,通过RT-PCR的方法获得丙型肝炎病毒C区基因片段。并将此片段克隆到真核细胞表达载体pcDNA3.1(+),得到重组质粒pcDNA-HCV/C,再将其通过肌肉注射免疫BALB/小鼠后,小鼠产生了抗HCV/C区抗体。  相似文献   

9.
小鼠4.5S RNA逆转座子cDNA的克隆及其表达载体的构建   总被引:2,自引:2,他引:0  
利用RT-PCR方法,从小鼠肝脏组织总RNA中扩增出4.5S RNA的cDNA.此cDNA被克隆到pGEM3Zf(+)质粒,酶切鉴定并测序。然后将该序列插入以虫荧光素酶基因作了报导基因的表达载体pSVluc20的PvuⅡ位点,构建;了4.5S RNA逆转座子的表达载体pSVluc20-4.5S,并对4.5S RNA逆转座子的生物学功能进行了研究。  相似文献   

10.
利用人胚胎肝组织提取总RNA,从总RNA 中分离纯化出m RNA,经逆转录得到cDNA 第一条链,并以之为模板和相应寡聚脱氧核苷酸为引物,进行PCR 合成人锰超氧化物歧化酶cDNA 基因,将所得cDNA 克隆到质粒pBluescriptSK 上,转化大肠杆菌DH5α细胞,进行诱导表达筛选,将筛选的克隆进行cDNA 全序列测定  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
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   

15.
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   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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   

20.
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   

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