溶菌酶在食品中的应用

溶菌酶(Lysozyme)，又称胞壁质酶，是一种专门作用于微生物细胞壁的水解酶，因其有溶菌作用，故命名为溶菌酶。溶菌酶是由129个氨基酸构成的单纯碱性球蛋白，化学性质非常稳定。由于细菌细胞壁对溶菌酶的敏感性这种作用，因而在食品领域获得了广泛的应用。     

溶菌酶结构特点及其应用

溶菌酶是一类对细菌细胞壁有水解作用的无毒、无害的蛋白质,通过对它的结构、性质、来源的研究,溶菌酶已广泛的应用于医药、生物工程和食品工业等多个方面.     

卵清溶菌酶激活剂的研究——Ⅲ、激活剂溶菌酶的微生物细胞脱壁效应

细胞融合是新近发展起来的生物工程技术之一,而细胞融合的主要关键步骤之一是酶法脱壁制备原生质体。早在1958年Romano等报导链霉菌属中一些种的细胞壁可以被溶菌酶溶解,Douglas首先用溶菌酶从链霉菌菌丝制备出原生质体,并用对噬菌体吸咐及血清学试验证明细胞壁确实溶解。随后Okarishi等研究了链霉菌原生质体形成和再生成细胞形态的条件。但由于不同的微生物之间的细胞壁的结构和组成有所不同,以致使它们对溶菌酶的敏感性也呈现出很大的差异,从而使溶菌酶在细胞融合中的脱壁作用受到一定的影响。前面两文已证明,激活剂LIA能     

Nocardia rubra细胞壁骨架(N-CWS)抑制小鼠Lewis肺癌的试验研究

以冻干Nocardia rubra细胞壁骨架注射剂对C57BL／6J小鼠移植肿瘤Lewis肺癌进行抑瘤试验，并进行荷瘤鼠外周白细胞计数和测定血清溶菌酶含量。结果表明，Nocardia rubra细胞壁骨架对Lewis肺癌的抑瘤率为37．2％，显示了明显的抑制肿瘤生长的作用。同时荷瘤小鼠外周血白细胞有明显升高，血清溶菌酶含量的增加也非常显著，提示其抗肿瘤过程中的非特异性免疫促进作用。     

卵清溶菌酶激活剂的研究(Ⅰ)——激活效应和激活动力学

前言 1922年Fleming在鸡蛋白中发现溶菌酶(E、C、3、2、1、17)以来,由于其在酶学理论研究上的重要地位和在工业、食品、卫生、医药、生物技术等方面具有日益增多而又十分广泛的应用价值,溶菌酶一直是酶学领域中经久不衰的热门研究课题。从分离纯化、理化特性、分子结构、空间构象到可能的作用机理的研究都获得巨大的进展。为了进一步弄清其作用机理,充分发挥其应用潜势,科学家们采用物     

食品抗氧化剂叔丁基对苯二酚与溶菌酶结合特性的荧光光谱学研究

叔丁基对苯二酚是一种被广泛应用的脂溶性酚类食品抗氧化剂,为揭示食品抗氧化剂叔丁基对苯二酚与溶菌酶的相互作用机理,利用荧光猝灭、同步荧光、三维荧光与荧光寿命的测定,从结合机理、亲和能力及结构改变等方面分析了叔丁基对苯二酚与溶菌酶的结合特性.结果表明:叔丁基对苯二酚能与溶菌酶形成不发光的基态复合物,常温下的结合常数约为3×104L/mol;该结合过程属自发行为,且氢键和范德华力在此过程中起主导作用;叔丁基对苯二酚的嵌插促使复合物的形成,并改变了溶菌酶的原有氨基酸残基微环境,但蛋白整体构象保持完整.     

从蛋壳蛋膜中分离溶菌酶

溶菌酶E.C.3.2.1.7.是一种糖苷水解酶,作用N-乙酰氨基葡萄糖和N-乙酰胞壁酸之间的β-1,4键,能使某些细菌细胞壁中的粘多糖成份分解,因而具有溶菌能力。在临床和食品工业上溶菌酶用于抗炎、消肿、增强抗菌素疗效以及防腐等。它的应用正在进一步开发,对它的需求也在不断增长。     

螺旋藻威化饼的研制

螺旋藻富含蛋白质，具有合理的氨基酸组成，含多种维生素、矿物质元素和微量元素，构成细胞壁和纤维素极少，很易被人类和动物消化。另外含有重要的螺旋藻多糖类，对防止心血管疾病、癌症等有显著的功效。基于螺旋藻这种高营养保健价值，国外自７０年代起就对其进行了广泛而深入的研究。现在螺旋藻已广泛应用于食品添加剂、化妆品、医药、保健品等人类健康事业。我国螺旋藻干粉产量现已占世界总量的４０％，大量培养具模型，其产品一     

蛋壳的加工方法及用途

蛋壳中约含有碳酸钙94％、有机物5％、碳酸镁、磷酸钙及胶质等。蛋壳制品可应用于食品、饲料等工业中。从蛋壳中能提取溶菌酶，溶菌酶又称胞壁质酶，是球蛋白类，具有溶解细胞的能力，有抗菌作用的粘多糖酶，在酸性溶液中可以耐热至100℃，溶菌酶的等电点为107，是一种十分稳定的蛋白酶。1蛋壳粉的加工方法收集新鲜的蛋壳后，用清水洗净去除杂质等。将洗净的蛋壳摊在干净的水泥地上，厚度约3cm，利用日光晒干，待水份蒸发后，经常翻动，晒到质松脆，手捏碎为准；或在烘房内烘干，此时温度可调到80℃左右，随时通风排潮，一般需要2～4小时，…     

一种溶菌酶的提取方法

溶菌酶是一种用途较为广泛的生化物质,强碱性蛋白酶,等电点高,分子量低。由于能催化格兰氏阳性细菌细胞壁粘多糖的水解,因而在医学上是一种有效的抗菌剂。鸡蛋的蛋清中含有丰富的上述物质,本文以鸡蛋清为原料,用一种简单方法提取溶菌酶。一、提取原理溶菌酶是一种强碱性蛋白,与氯化物、碘化物及碳酸盐等容易形成结晶盐。在蛋清中加入一定量的上述化合物,并调节溶液的PH值到其等电点(PH=10.5),在     

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.     

A computer generator for randomly layered structures

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

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.     

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.