羊肚菌多糖提取分离及生物活性研究进展*

羊肚菌(Morchella spp.)是一种珍稀食药用真菌,从羊肚菌中提取的多糖在抗癌、抗氧化、降血糖、降血脂及免疫调节等方面具有良好的生物活性,在食品、药品和保健品开发方面具有广阔的应用前景。羊肚菌多糖的有效提取是对其进行结构解析和生物活性研究的基础,不同的提取方式对羊肚菌多糖的结构和生物活性具有一定影响。羊肚菌多糖的结构特性如分子量、单糖组成、一级结构等,对其生物活性具有很大影响,因此研究羊肚菌多糖的结构对揭示其生物活性及作用机制具有重要意义。针对羊肚菌多糖进行综述,总结羊肚菌多糖提取分离、结构解析及生物活性的研究进展,分析羊肚菌多糖生物活性的作用机制,并对今后研究方向提出展望,以期为羊肚菌多糖的研究与开发提供理论基础。     

食药用真菌多糖构效关系研究进展

真菌多糖具有抗病毒、抗凝血、抗肿瘤、免疫调节、降血脂、延缓衰老等多种生物活性,而多糖的功能与结构密切相关。多糖结构与功能关系的研究已经成为人们关注的一个热点。综述了食药用真菌多糖一级结构、高级结构及多糖的理化性质与其生物学活性之间的关系。     

天然多糖羧甲基化对其生物活性影响的研究进展

多糖由于具有抗氧化、抗肿瘤、调节免疫、降血糖等生物活性而受到诸多领域的关注。多糖的结构与其生物活性相关,经过化学修饰会增强其生物活性或产生新的活性。本文就天然多糖的羧甲基化修饰及对其生物活性的影响进行综述,以期为多糖的研发与应用提供理论参考。     

改性酵母葡聚糖——CMG的部分性质及其在溶液中构象行为

多糖的生物、药物活性与其化学结构之间有非常重要的关系．许多抗肿瘤的葡聚糖都是以β－（１－３）连接为主链,具有β－（１－６）分支和三股螺旋结构的葡聚糖大分子［１,２］．多糖的生物活性除受主链的连接方式、分子大小和分支度的影响外,还与其高级结构密切相关［...     

灰树花活性多糖构效关系研究进展

灰树花是一种珍贵的食药用菌,具有降血糖、抗肿瘤、免疫调节和抗病毒等多种生物活性。灰树花多糖是其主要的活性成分,多糖的生物活性与多糖的结构密切相关。本文综述了从20世纪80年代起国内外已报道的灰树花活性多糖的结构表征。部分研究认为多糖的降血糖活性可能与β-1,6-葡聚糖主链化学结构相关,而灰树花多糖结构为β-1,6主链或β-1,3主链葡聚糖时具有较好的抗肿瘤活性。然而多糖结构异常复杂,精细结构的解析困难,导致目前灰树花多糖结构表征一般止步于单糖组成、分子量、糖苷键类型、分支结构和粗略分子链构象,但二维核磁(two dimensional nuclear magnetic resonance,2D-NMR)和高分辨质谱联用等技术的发展将有助于解开灰树花多糖构效关系,并为灰树花活性多糖的开发利用提供理论依据。     

水溶性甘草多糖的分离纯化、结构及生物活性研究进展

甘草是广泛使用的中药材之一.甘草中含有多种活性物质,甘草多糖作为主要的活性大分子,具有抗肿瘤、抗病毒、抗氧化、抗补体以及免疫调节等生物活性.本文对近年来水溶性甘草多糖的分离纯化、结构解析以及生物活性研究的最新进展进行综述.     

β—1,—3葡聚糖的结构与功能

β－１,３－葡聚糖是一类具有抗癌及免疫调节等生物活性的生物大分子其高级结构为单股和３股螺旋体,它的生物活性,理化特性与其分子结构有一定对应关系。     

多糖构效关系研究进展

随着化学和生物技术的飞速发展,多糖已经成为生命科学研究的热点领域之一,其结构和生物活性的关系对于新药的研发显得尤其重要.本文从多糖结构与其三大活性抗肿瘤、抗病毒、抗凝血的角度,具体阐述多糖的结构如主链结构、取代基修饰、分子量、聚合度等对生物功能的影响,为定向合成设计糖类药物和先导化合物的改造提供参考.     

金耳多糖的分离纯化及其化学结构的研究

金耳(Tremella aurantialbaBandoni et Zang)是我国稀有的珍贵食用菌和药用菌,具有化痰、止咳、定喘、调气、平肝阳之功效。多糖作为金耳的主要生理活性成分之一,具有增强免疫、降血糖、降血脂、抗肿瘤、抗血栓和抗氧化等作用。但由于技术手段的落后,金耳多糖的化学研究比较滞后,其药理活性的研究也主要集中于粗多糖的研究,对均一多糖的化学结构分析和生物活性还很少涉及,这种状况对合理开发和利用金耳多糖产品造成很大影响。该研究对金耳子实体多糖进行了提取、分离纯化、结构鉴定、分子修饰和生物活性研究,为更好地开发金耳资源提供可靠的理论依据。     

杏鲍菇多糖的研究进展

综述了杏鲍菇多糖的提取、纯化、结构表征、生物活性以及应用研究进展,展望了杏鲍菇多糖对人体保健的应用前景,为杏鲍菇多糖将来的研究和应用提供科学依据。     

Determining the polysaccharide composition of plant cell walls

The plant cell wall is a chemically complex structure composed mostly of polysaccharides. Detailed analyses of these cell wall polysaccharides are essential for our understanding of plant development and for our use of plant biomass (largely wall material) in the food, agriculture, fabric, timber, biofuel and biocomposite industries. We present analytical techniques not only to define the fine chemical structures of individual cell wall polysaccharides but also to estimate the overall polysaccharide composition of cell wall preparations. The procedure covers the preparation of cell walls, together with gas chromatography-mass spectrometry (GC-MS)-based methods, for both the analysis of monosaccharides as their volatile alditol acetate derivatives and for methylation analysis to determine linkage positions between monosaccharide residues as their volatile partially methylated alditol acetate derivatives. Analysis time will vary depending on both the method used and the tissue type, and ranges from 2 d for a simple neutral sugar composition to 2 weeks for a carboxyl reduction/methylation linkage analysis.     

In silico studies of plant primary cell walls – structure and mechanics

Primary plant cell wall (PCW) is a highly organized network, its performance is dependent on cellulose, hemicellulose and pectic polysaccharides, their properties, interactions and assemblies. Their mutual relationships and functions in the cell wall can be better understood by means of conceptual models of their higher-order structures. Knowledge unified in the form of a conceptual model allows predictions to be made about the properties and behaviour of the system under study. Ongoing research in this field has resulted in a number of conceptual models of the cell wall. However, due to the currently limited research methods, the community of cell wall researchers have not reached a consensus favouring one model over another. Herein we present yet another research technique – numerical modelling – which is capable of resolving this issue. Even at the current stage of development of numerical techniques, due to their complexity, the in silico reconstruction of PCW remains a challenge for computational simulations. However, some difficulties have been overcome, thereby making it possible to produce advanced approximations of PCW structure and mechanics. This review summarizes the results concerning the simulation of polysaccharide interactions in PCW with regard to network fine structure, supramolecular properties and polysaccharide binding affinity. The in silico mechanical models presented herein incorporate certain physical and biomechanical aspects of cell wall architecture for the purposes of undertaking critical testing to bring about advances in our understanding of the mechanisms controlling cells and limiting cell wall expansion.     

药用昆虫多糖的研究进展

中医以昆虫入药,在两千多年里积累了丰富的临床经验。近年来,随着天然药物研究技术不断的发展,昆虫多糖的生物学活性被不断发现,人们对于药用昆虫多糖的研究也越来越广泛和深入。本综述通过查阅近年来有关药用昆虫多糖的资料文献,从提取分离、结构研究、药理活性三个方面总结、分析了近年来有关药用昆虫多糖的研究成果,希望可以为相关研究人员提供借鉴。目前,昆虫多糖提取分离的方法包括水提醇沉法、碱液提取法和酶解法。尽管药用昆虫多糖的结构研究报道较少,但已发现,昆虫多糖的结构比植物多糖和真菌多糖更复杂,大多为蛋白聚糖,组成的单糖种类较多。昆虫多糖具有多种药理活性,在免疫调节、抗氧化、抗肿瘤、抗血栓及抗过敏等方面作用突出。     

Heparin and heparan sulfate: biosynthesis, structure and function

Heparin and heparan sulfate glycosaminoglycans are acidic complex polysaccharides found on the cell surface and in the extracellular matrix. Recent progress has uncovered a virtual explosion of important roles of these biopolymers in fundamental biological processes. Advances in the understanding of biosynthesis and structure and the development of novel analytical methods for composition and sequence analysis have provided remarkable insights into structure/function relationships of these complex and once elusive polysaccharides.     

A computer-assisted structural analysis of regular polysaccharides on the basis of 13C-n.m.r. data

A computerised approach to the structural analysis of unbranched regular polysaccharides is described, which is based on an evaluation of the 13C-n.m.r. spectra for all possible primary structures within the additive scheme starting from the chemical shifts of the 13C resonances of the constituent monosaccharides and the average values of the glycosylation effects. The analysis reveals a structure (or structures), the evaluated spectrum of which resembles most closely that observed. The approach has been verified by using a series of bacterial polysaccharides of known structure and, in combination with methylation analysis data, for the determination of the presently unknown structures of the O-specific polysaccharides from Salmonella arizonae O59 and O63, and Proteus hauseri O19.     

多糖抗病毒作用研究进展Ⅰ-多糖抗病毒作用

近年来,多糖的抗病毒作用已引起极大关注。本文综述了多糖的抗病毒作用,概述了多糖构效关系、抗病毒机理、分子修饰及其与其他抗病毒药物的协同作用。多糖抗病毒药物研究前景广阔。     

细菌多糖的生物合成机制

近些年来,细菌多糖因其重要的医学价值和工业用途引起了人们的广泛关注。随着细菌基因组的不断测序,众多与细菌多糖合成相关的基因簇被发现。不同多糖合成基因簇的比对分析结果表明,尽管自然界中多糖的结构复杂多变,但是它们的合成机制却是相对单一的。本文就当前国际国内不同细菌多糖的合成机制,以及多糖合成途径中相关糖基转移酶和聚合酶的研究进展进行了论述。     

Lamellar structures in rat ova and their chemical composition.

The paper represents a study of the chemical composition of lamellar structures in rat ova during cleavage based on the morphology of their submicroscopic structure after the action of various fixatives and various methods of contrasting ultrathin sections and on the employment of cytochemical methods. Reactions to RNA, polysaccharides, acid and alkaline phosphatase, non-specific esterase, glucoso-6-phosphatase and succinate dehydrogenase were tested on a submicroscopic level; lipids were tested on a light-microscopic level. The results have shown that the lamellae are composed of proteins. No RNA, polysaccharides, lipids or any of the investigated enzymes were detected in lamellar structures. Lamellar structures, therefore, are considered to be storage material chiefly used in the second half of the cleavage for developmental processes in the rat ovum.