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1.
以稻瘟病菌菌株P131和Y34为材料,利用REMI技术构建了含有8000个转化体的突变体库.对REMI转化的部分条件进行了优化,比较了不同限制性内切酶(XhoI、ApaI和EcoRV)之间REMI转化效率的差异.结果表明,稻瘟菌分生孢子在摇培32h和Drisdase消化菌丝2h或3h时较适宜REMI转化;XhoI和ApaI之间没有明显差异,而两者的转化率高于EcoRV.  相似文献   

2.
利用限制性内切酶介导整合(REMI)技术,通过插入线性化质粒DNA获得了生物防治番茄灰霉病(Botrytis cinerea)效果优于初发菌Trichoderma viride T21菌株(初发菌)的3个变异株Ttrm31、Ttrm34和Ttrm55.变异株本身产生的和诱导番茄植株产生的几丁质酶和β-1,3-葡聚糖酶的活性均比初发菌高,因此,通过REMI技术可以获得新的有益变异株,在一定程度上提高了生物菌株防治番茄灰霉病的水平,尤其是提高诱导番茄抗病水平.对侵染花器和叶片的灰霉病防效分别比原生物防治木霉菌株提高了16.9%和89/6,说明REMI技术可以用于改良生防木霉菌株的功能,提高生物防治效果.  相似文献   

3.
灰绿曲霉高产纤维素酶突变株的选育   总被引:5,自引:0,他引:5  
以一株具有较高纤维素酶活性的野生菌株-灰绿曲霉XC9为出发菌株,经过紫外线、氯化锂、甲基磺酸乙酯(EMS)等物理化学诱变剂多重诱变处理,获得了抗葡萄糖阻遏的突变株E2-26、E5-65、U6-31和EU7-22,其CMC酶活与出发菌株相比分别提高至1.7、1.4、1.3、2.0倍.突变株经PDA斜面接种传代5次后产酶性能仍然保持稳定.变株的菌丝、孢子颜色也发生了较大的改变.对突变株EU7-22的形态结构进行了观察,并与出发菌株XC9作了发酵性状的比较,发现其产酶性能有了明显提高.  相似文献   

4.
通过筛选稻瘟菌(Magnaporthe grisea)P131小种的REMI(Restriction Enzyme MediatedIntegration)转化体库获得对水稻品种梅雨明致病性变异的突变体,命名为PX1.与野生型菌株P131相比,该突变体对水稻品种梅雨明致病性丧失,在洋葱表皮上侵染钉形成率显著降低,而孢子萌发率和附着胞形成率差异不显著.遗传分析表明,该突变体的突变表型和潮霉素抗性标记共分离,说明突变是由于外源质粒插入引起的,因此,可以此为标记克隆控制该表型的基因.  相似文献   

5.
灰绿曲霉高产纤维素酶突变株的选育   总被引:5,自引:1,他引:5  
以一株具有较高纤维素酶活性的野生菌株-灰绿曲霉XC9为出发菌株,经过紫外线﹑氯化锂﹑甲基磺酸乙酯(EMS)等物理化学诱变剂多重诱变处理,获得了抗葡萄糖阻遏的突变株E2-26﹑E5-65﹑U6-31和EU7-22,其CMC酶活与出发菌株相比分别提高至1.7、1.4、1.3、2.0倍.突变株经PDA斜面接种传代5次后产酶性能仍然保持稳定.变株的菌丝、孢子颜色也发生了较大的改变.对突变株EU7-22的形态结构进行了观察,并与出发菌株XC9作了发酵性状的比较,发现其产酶性能有了明显提高.  相似文献   

6.
为提高重组β-葡萄糖醛酸苷酶的底物特异性,通过易错PCR方法对其进行突变并构建突变体文库,利用薄层层析和高效液相色谱对突变文库进行筛选,获得了突变株PGUS(M51)E,其底物特异性提高了41%。突变酶的酶学特性研究发现,该突变酶的最适pH值和温度较PGUS-E无显著变化,酶活力下降了16.86%,T。值提高了5℃;序列分析结果表明:PGUS(M51)-E共发生5处突变,其中3处发生在糖基结合域。因此,利用定向进化策略能有效提高伊葡萄糖醛酸苷酶的底物识别特异性。  相似文献   

7.
以产油丝状真菌深黄被孢霉M6-22(Mortierella isabellina 6-22)为出发菌株,利用亚硝基胍诱变技术筛选到一株对潮霉素药物敏感的菌株Mortierella isabellina 6-22-4,同时构建了含有潮霉素抗性基因表达单元和深黄被孢霉△6-脂肪酸脱氢酶基因5'与3'端部分同源序列的重组质粒PD4MI6,用于对深黄被孢霉△6-脂肪酸脱氢酶基鼠的敲除.通过PEG/CaCl2介导的原生质体转化法,将质粒PD4MI6转化入深黄被孢霉M6-22-4菌株.转化子经潮毒素抗性选择平板筛选、分子检测获得了一个△6-脂肪酸脱氢酶基因缺失的突变株Mut6.气相色谱分析结果显示,该突变株γ-亚麻酸特征峰消失,相应地亚油酸产量显著增加.培养结果表明该突变株的菌落形态、颜色及生长状况与出发菌株M6-22或M6-22-4相比均有显著改变.  相似文献   

8.
本实验菌株醋酸钙不动杆菌(Acinetobacter calcoaceticus)M1-7的最佳紫外诱变时间为60,s.利用紫外诱变后涂布到添加不同脂肪酶底物和分解产物的分离培养基,筛选出具有抗性的正突变株.其中柠檬酸钠抗性突变菌株UN9最高酶活力达15.960,U/mL,比出发菌株提高了130.97%,远远高于琥珀酸钠、正丁酸、正己酸、三丁酸甘油酯等抗性突变菌株.经5次传代后,菌株UN9遗传性能稳定,平均酶活力为15.866,U/mL.  相似文献   

9.
采用羧甲基纤维素(CMC)平板初筛和50℃培养,筛选到一株纤维素酶活力较高的耐高温霉菌MY菌株,其CMC培养基最适pH为6.0,培养温度为40℃,最佳产酶时间为5d.以MY菌株为出发菌株,分别采用紫外线和硫酸二乙酯诱变,以透明圈直径与菌落直径的比值(HC值)提高30%以上或菌落形态发生明显变异为筛选指标,共筛选到97株突变株;通过测定粗酶液CMC酶活力,从中筛选出29株CMC酶活力提高30%以上的菌株;结合突变菌株的传代稳定性实验,最后筛选得到1株性能优良的霉菌MY004突变株,其CMC酶活力比原始菌株MY提高了80.6%.  相似文献   

10.
采用羧甲基纤维素(CMC)平板初筛和50℃培养, 筛选到一株纤维素酶活力较高的耐高温霉菌MY菌株, 其CMC培养基最适pH为6.0, 培养温度为40℃, 最佳产酶时间为5d. 以MY菌株为出发菌株, 分别采用紫外线和硫酸二乙酯诱变, 以透明圈直径与菌落直径的比值(HC值)提高30%以上或菌落形态发生明显变异为筛选指标, 共筛选到97株突变株; 通过测定粗酶液CMC酶活力, 从中筛选出29株CMC酶活力提高30%以上的菌株; 结合突变菌株的传代稳定性实验, 最后筛选得到1株性能优良的霉菌MY004突变株, 其CMC酶活力比原始菌株MY提高了80.6%.  相似文献   

11.
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   

12.
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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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