植酸酶液体发酵条件及酶学性质的研究

植酸酶产生菌黑曲霉 90 3(Aspergillusniger)的最适产酶条件 :初始pH5 .0～ 6 .5 ,温度2 9± 1℃ ,培养时间 4d ,2 5 0ml三角瓶发酵液的装量为 5 0ml,一定量的Fe2 +和Mn2 +对产酶有促进作用 ;酶的最适作用pH为 5 .5～ 6 .0 ,最适作用温度为 37℃ ,该酶在 pH3.0～ 7.0 ,温度 30～ 5 0℃时稳定性较好。     

野生革耳菌组成型漆酶的生成条件及性质研究

首次发现野生革耳菌 (Panusrudis)在 39℃液体振荡培养条件下 ,不需诱导剂的诱导 ,能持续产生漆酶 .优化后培养基的碳氮源分别为 2 %蔗糖和 2 6mM酵母抽提物 ,最高酶活达 1 .6× 1 0 4U/L ,属于目前已知的组成型漆酶高产菌株 .发酵液经硫酸铵沉淀 ,DEAE Sepharose ,SephacrylS 2 0 0 ,MonoQ柱层析分离纯化后 ,可得电泳纯漆酶蛋白 .该酶为单体蛋白 ,分子量为 58kDa .以愈创木酚为底物 ,该酶的最适作用pH为4 5,最适反应温度为 50℃ ,Km值为 0 .2 1mM ,并表现出较好的热稳定性 ,具有良好的基础研究和工业应用价值     

绿豆几丁质酶的纯化和酶学性质分析

利用亲和色谱Affi-gel和离子交换色谱SP-Toyopearl从绿豆种子中分离纯化出几丁质酶.纯化的蛋白通过SDS-聚丙烯酰胺凝胶电泳鉴定达到电泳纯,分子质量为30.8kDa.还原和非还原状态下的几丁质酶蛋白均显示单一区带,说明该几丁质酶为单倍体蛋白.通过等点聚焦法测得pI为6.3.该酶的最适pH为5.4,最适反应温度为40～50℃.     

组氨酸标签木聚糖酶的构建表达和酶特性鉴定

通过改变终止密码子位点,在一个耐热木聚糖酶突变株DSB的C末端添加了6聚组氨酸标签(His-tag),并完成了表达和酶特性鉴定.通过PCR将嗜热真菌DSM 10635来源的木聚糖酶突变体基因dsb的终止密码子序列定点突变为谷氨酸密码子序列,连接到表达载体pET-22b(+),转化Escherichia coli.BL21(DE3),诱导表达的耐热木聚糖酶DSB在C端含有6×His-tag.表达产物经硫酸铵分级沉淀和Ni Sepharose层析纯化,获得了电泳纯重组酶DSB.结果表明:添加组氨酸标签的酶与原始酶相比,酶学特性无变化.SDS-PAGE电泳结果显示该酶分子量约为23 kDa,重组酶最适pH为6.5,最适温度为75℃,在pH 5¹0具有良好的稳定性,在pH 6.5,70℃条件下处理30min相对酶活力仍保留80%以上.     

花生几丁质酶的纯化及酶学性质研究

本课题利用亲和色谱和凝胶过滤色谱法从花生种子中分离得到了几丁质酶.经SDS-PAGE鉴定,该酶蛋白已达电泳纯,分子量约34.4 kD.在还原和非还原状态下均显示单一区带,表明其为单体蛋白.此外,通过等电聚焦法可测得该酶等电点为5.1.而酶学性质的相关研究则表明:该酶最适pH为5.4,最适反应温度为40～50℃.     

产果胶酶菌株的筛选鉴定及其产酶条件的研究

为筛选果胶高效降解菌株,结合HC比值(透明圈H与菌落直径C的比值)和果胶酶活力测定,从桔子园土壤和腐烂的水果等处筛选得到1株产果胶酶活力较强的菌株M3,结合菌株形态特征观察和ITS rDNA基因序列分析,确定该菌株为聚多曲霉(Aspergillus sydowii).经发酵产酶试验可知,该菌株的最适发酵产酶条件为培养温度30℃,初始pH4.5,接种量(体积分数)7%,培养时间4 d.在该条件下发酵,果胶酶活力可达42.01 U.mL-1.     

一种改进的漆酶酶活检测方法

以 2 ,2′ -连氮 -双 (3-乙基苯并噻唑 - 6 -磺酸铵 ) (简称ABTS)为漆酶A、B的底物 ,采用UV - 2 2 0 1型紫外 -可见分光光度计连续记录酶反应在 2 5℃ ,4 2 0nm波长下的时间历程曲线 ,并求取最初部分的斜率以计算漆酶酶活的方法 .该方法直观、方便、准确且可靠 .在 2 5℃的 0 .0 4mol/LBritton Robinson缓冲溶液中 ,漆酶A、B的最适 pH值分别为 4 .0和 4 .5 .在 2 5℃最适 pH值的Britton Robinson缓冲液中 ,由双倒数作图法求得漆酶A、B的米氏常数Km 分别是 6 .6 4× 1 0 - 5mol/L和 2 .2 1× 1 0 - 5mol/L ,漆酶A、B的最大米氏反应速度Vmax分别是 1 4 2 5μmol.M (L·min)和 32 5μmol.M (L·min) .漆酶A、B的酶活分别为 2 2 99μmol·min- 1·L- 1和 1 1 4 8μmol·min- 1·L- 1.     

极耐热内切葡聚糖酶Cel12B的基因克隆、表达和酶学性质的研究

极耐热酶在工业生产中有可观的潜在用途，为此从极端嗜热厌氧细菌海柄热袍菌中通过PCR方法克隆出Cel12B基因，构建重组表达质粒pET-20b-Cel12B，转化至大肠杆菌JM109（DE3）诱导表达后，获得极耐热重组内切葡聚糖酶．经过热处理和组氨酸亲和层析柱纯化，获得电泳纯单一条带，酶学性质测定表明：最适作用pH为6．0，最适作用温度90℃，在pH5．3～6.5之间酶活力稳定，90℃半衰期70min。     

阴离子交换树脂固定化果胶酶研究

以阴离子交换树脂为载体、戊二醛为交联剂,对果胶酶进行固定化分析,探讨了温度、pH值、时间、加酶量、戊二醛浓度、交联温度、交联时间对果胶酶固定化效果的影响,同时对固定化果胶酶的酶学特性进行研究.结果表明,果胶酶最佳固定化条件为:温度为40℃,pH值为5.5,固定化6 h,加酶量为0.75 mL/g树脂,戊二醛体积分数为0.1%,交联温度为4℃,交联时间4 h.在此条件下,固定化果胶酶的酶活回收率可达到80%以上.酶学特性试验表明,固定化果胶酶最适温度为60℃,最适pH值为4.0,具有较好的操作稳定性.     

猪肾溶茵酶的纯化和部分性质研究

猪肾溶菌酶提取液经过正丁醇脱脂,(NH4)2SO4沉淀,得到粗酶液,再经过CM-Sepharose FF阳离子层析柱和sephacryl S-100凝胶过滤层析纯化得到电泳纯的溶菌酶.该酶的比活力为162.45,提纯倍数为113.6,回收率为16.89%.该酶对溶壁微球菌作用的最适温度为45℃,最适作用的pH为6.0,在50℃以下和pH 4.5～9.0之间都有较好的稳定性.酶分子量约为15.0 kd,其米氏常数为0.013 5 g/m L.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

An Index mechanism for multi-scale view in spatial databases

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.     

A computer generator for randomly layered structures

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

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

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。     

Exciton Seebeck in Molecular Systems

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     

Achieving Unusual States of Matter Under High Pressure

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     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

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.     

An improved R-tree based on childnode''s probability

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).     

Integrating GIS Web services based on mediating architecture

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.