菌类多糖链构象及其表征方法研究进展 （专题报道）

 概述了菌类多糖在溶液中链构象及其表征方法的研究进展.主要报道从各种真菌（香菇、茯苓、灵芝、木耳、黄单胞菌、裂褶菌等）中提取的多糖在溶液中的分子量、分子形态和尺寸，即链构象.同时介绍多糖链构象对生物活性的影响，并且指出多糖刚性链带电基团及适量分子量有利于促进它与免疫细胞上受体结合，从而抑制肿瘤细胞增殖.由此表明，多糖链构象的研究对弄清其生物功能和推动生命科学发展十分重要.多糖在溶液中主要以无规线团、双螺旋、三螺旋、蠕虫状、棒状链以及聚集体构象存在，它取决于单糖组成、糖苷键、支链结构以及分子内和分子间作用力.测定链构象的方法主要包括光散射、黏度、显微技术（透射电镜，扫描电镜以及原子力显微镜）、微量热法和小角X-射线散射等.此外，介绍了多糖溶液理论以及计算链构象参数的表达式.

ADVANCES IN CONFORMATIONS AND CHARACTERIZATIONS OF FUNGI POLYSACCHARIDES (Special Topic)

This paper summarizes the current research results on the chain conformations of the fungi polysaccharides in solution and characterization methods.The molecular weight,particle size,and chain conformation of various polysaccharides exacted from mushrooms including Lentinus edodes, Poria cocos,Ganoderma lucidum,Auricularia auricula-judae,Xanthomonas,Schizophyllan,etc. in solution are introduced,and the relationships between the bioactivity and the chain conformation are outlined.It is concluded that extended chain,charged groups and moderate molecular weight of the polysaccharides are beneficial to enhance the antitumor activities,as results of the increasing the interaction between polysaccharide molecules and immune system.It is indicated the importance of understanding the relationship between polysaccharide chain conformation and biological activity.Polysaccharides mainly exist as random coil,double helix,triple helix,the worm-like and rod|like chain conformations,as well as aggregates in solution,depending on the type of monosaccharide and glycosidic link,the branch chain structure and intermolecular interactions.The major characterization methods include light scattering,viscosity,microscopy (TEM,SEM and atomic force microscope),microcalorimetry and small angle X|ray scattering.In addition,the polysaccharides solution theory and the calculation expression of chain conformation parameters are represented and discussed.