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1.
乳酸乳球菌电转化条件的研究   总被引:10,自引:0,他引:10  
以质粒pTRKH2为材料,对乳酸乳球菌MG1614进行电转化条件的研究.实验结果表明,在电转化过程中,电场强度、电阻大小、细胞生长状态和电击后菌株复苏时间均对转化效率有明显影响,得到了乳酸乳球菌的最适电转化条件为:对数生长中期的细胞,经1%甘氨酸处理,在10kVcm电场强度、400Ω电阻下电转化,转化后细胞在SGM17培养液中培养2h后涂布选择性培养基,转化率(转化子个数与DNA质量之比)可达1.2×103个μg,比优化前的转化效率提高近100倍.  相似文献   

2.
用枯草芽胞杆菌质拉载体pNQ122和含有中性蛋白酶基因的重组质粒pMPR8转化环状芽胞杆菌C-2,转化频率为1.0×103转化子/μgDNA.含有pMPR8的转化子能在酪蛋白平板上形成清晰的水解圈,其蛋白酶活性与相同质粒转化枯草杆菌DB104所得酶活性相近.Southern杂交结果证实了转化细胞中存在质粒pNQ122和pMPR8,两种质粒在该菌中的稳定性差别很大.  相似文献   

3.
以5、10和20μmol/L姜黄素处理MGC80-372h,细胞存活率随药物浓度及处理时间依赖性下降,并呈现典型的凋亡细胞形态,以0、10、20及30μmol/L姜黄素处理细胞24h后,20μmol/L,以上的处理组DNA琼脂糖电泳显示均有典型的凋亡梯形条带,同样条件处理后分别对断裂及未断裂DNA作定量测定,计算细胞凋亡率分别为7.3%,39.2%,50.5%和64.3%,表明姜黄素具有诱导MGC  相似文献   

4.
CaCl2法质粒转化最佳条件的探讨   总被引:7,自引:0,他引:7  
CaCl2法质粒转化中的一些关键性步骤的实验条件进行了探讨结果表明,CaCl2处理对制备感受志受体菌是至关重要的,CaCl2处理后的受体菌在4℃放置16~24h是必要的.CaCl2处理浓度以0.075mol·L-1最佳.为了得到足够的转化菌落,质粒加入量不应低于0.2μg.  相似文献   

5.
根癌农杆菌电击转化条件的研究   总被引:1,自引:0,他引:1  
探索了根癌农杆菌EHA105的高效转化方法.将双元载体质粒pBIN19/glgB经电击转化法导入根癌农杆菌EHA105,研究不同实验条件对转化率的影响.结果表明:在细胞浓度OD600为1.0时进行电转化,转化率最高,达到每微克DNA1.12×105CFU;当电场强度为11 kv/cm,转化率最高,达到每微克DNA1.78×105CFU;在一定的细胞浓度范围内,电击转化率与细胞浓度密切相关,转化率随着细胞浓度的上升而上升;质粒大小能影响电击转化率,转化率随着质粒的增大而下降.应用该优化的电击转化条件将双元载体质粒pBIN19/glgB成功导入根癌农杆菌EHA105,构建了植物双元表达载体.  相似文献   

6.
乙型肝炎病毒(HBV)DNA免疫的初步研究   总被引:1,自引:1,他引:0  
用聚合酶链反应(PCR)扩增了编码HBVsAg的基因序列,将其插入到pcDNA3载体中,位于人巨细胞病毒(CMV)早期启动子下游.重组质粒pcDNA3-sAg转染细胞后检测到HBsAg表达.用纯化后的重组质粒直接注射到BALB/C小鼠骨骼肌内,诱发实验小鼠产生了抗HBsAg特异性抗体.PCR扩增未检测到注射部位及肝脏细胞染色体中有外源HBVDNA整合  相似文献   

7.
利用电穿孔法将外源基因导入未经前处理的水稻成熟胚盾惩细胞,质粒为pACT1-F,其上带有受水稻肌动蛋白基因actin1启动控制的GUS(uidA)报告基因,电穿孔实验的条件为100μgDNA/ml缓冲液,310V/cm场强及900μF电容,通过GUS基因瞬时表达实验室证明只需一次脉冲处理便可在一个胚上获得几十个数百个转化细胞,并且发现盾片细胞较胚上其它部位的细胞更易于转化。  相似文献   

8.
报导光合细菌球形红假单胞菌与酿酒酵母跨界原生质体融合的最初产物细胞F0和F0a在连续96小时的培养过程中细胞DNA含量的变化规律.酵母及光合细菌DNA含量分别为(4.21±0.04)×10-8μg/cel和(2.44±0.12)×10-8μg/cel.F0培养24小时DNA含量为(10.5±0.59)×10-8μg/cel,到培养96小时为(5.30±0.40)×10-8μg/cel,高于任一亲株;而F0a则从(17.1±0.59)×10-8μg/cel降低至(9.27±0.37)×10-8μg/cel,高于双亲DNA含量之和.经统计学t检验,融合产物DNA含量与双亲DNA含量均存在显著差异t>t0.01(10).本研究表明原生质体融合初期,遗传物质DNA在整合过程中数量逐步降低后可达稳定水平,而其含量高于任一亲株细胞的基本规律.  相似文献   

9.
水稻原生质体高频分裂及基因转化   总被引:2,自引:0,他引:2  
从粳稻品系898和籼稻不育系珍籼A的悬浮细胞系中制备的原生质体,分裂频率分别达18.9%和35%。低压脉冲电泳仪介导外源基因转移的水稻原生质体,分裂频率也在10%以上,转化的小细胞团中检测到外原基因Gus的表达,对原生质体的制备、培养及转化作了下述改进:(1)添加2μg/L2,4-D的N6培养基培养悬浮细胞及原生质体可获高频分裂,添加0.3μg/L6-BA或0.1μg/L NAA不利于分裂;(2)  相似文献   

10.
用CPR技术从纯化的乙型肝炎病毒核酸中扩增出perS2-S基因,并将其定向克隆于真核表达质粒pcDNA3.1(+)中,构建成带有完整的乙肝表面前S2抗原基因和S基因的重组质粒。重组质粒经酶切及部分序列分析鉴定后,瞬时转梁小鼠L细胞,ELISA法检测到培养上清液有HBsAg表达。用纯化的重组质粒静脉、肌肉和皮下注射免疫BALB/c小鼠,首次接种质粒DNA3周后,血清抗体开始出现,再次加强2周后,阳性  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.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
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   

15.
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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   

19.
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   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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