弯斑蛸多糖纯化及对小鼠脾细胞增殖的影响

将弯斑蛸粗多糖COG经精制得POG,再通过离子交换和凝胶柱层析纯化,经化学法和红外光谱确定主要组成和结构特征,用MTT比色法测定脾细胞的增殖.结果表明:柱层析得到的POGⅠ、POGⅡ和POGⅠ-1总糖含量在26.3%~42.2%之间,总糖胺聚糖含量均高于30%,葡萄糖醛酸含量接近20%,红外光谱提示均具有典型的糖胺聚糖特征;各多糖对小鼠脾细胞增殖均有明显的促进作用,纯度最高的POGⅠ-1促进作用最强.该弯斑蛸多糖为氨基己糖和葡萄糖醛酸组成的多糖,具有增强免疫作用.     

Circular proteoglycans from sponges: first members of the spongican family

Species-specific cell adhesion in marine sponges is mediated by a new family of modular proteoglycans whose general supramolecular structure resembles that of hyalectans. However, neither their protein nor their glycan moieties have significant sequence homology to other proteoglycans, despite having protein subunits equivalent to link proteins and to proteoglycan monomer core proteins, and glycan subunits equivalent to hyaluronan and to the glycosaminoglycans of hyalectans. In some species, these molecular components are assembled into a structure with a circular core formed by the link protein- and hyaluronan-like subunits. Besides their involvement in cell adhesion, these sponge proteoglycans, for which we propose the term spongicans, participate in signal transduction processes and are suspected to play a role in sponge self-nonself recognition. Their in vivo roles and the mild methods used to purify large amounts of functionally active spongicans make them ideal models to study the functions and possible new applications of proteoglycans in biomedical research. Received 21 May 2002; received after revision 5 July 2002; accepted 10 July 2002 RID="*" ID="*"Corresponding author.     

糖胺聚糖类物质产生菌的筛选及其鉴定

利用糖胺聚糖能与氯代十六烷基吡啶反应产生白色混浊的性质，从不同来源的菌种中，筛得4株菌种，再通过琼脂糖凝胶电泳，筛选得到一株糖胺聚糖产生菌GS36．根据形态及生理生化试验鉴定，初步判定为坚实芽孢杆菌．其发酵产物经纯化后通过红外光谱测定初步鉴定为硫酸软骨素．     

蛋白聚糖NG2中硫酸软骨素糖胺聚糖链调节稳定转染NG2的U251细胞迁移能力

应用PCR反应使编码蛋白聚糖NG2的核苷酸在3064-3065位置的AG突变成为GC， 构建突变型NG2/S999A. 用表达野生型NG2和突变型NG2/S999A及空白表达载体分别稳定转染人成胶质细胞瘤U251. 应用Western Blot方法鉴定转染后的U251细胞表达野生型及突变型NG2的状态， 证实突变型NG2A999稳定转染的U251细胞株表达的NG2缺失硫酸软骨素葡糖胺聚糖链（C S-GAG）. 比较了3种U251细胞株的迁移， 表明蛋白聚糖NG2中CS-GAG链影响细胞的迁移能 力.     

Changes in glycosaminoglycan sulfation and protein kinase C subcellular distribution during differentiation of the human colon tumor cell line Caco-2

Summary During the spontaneous differentiation (day 5 to day 15 of the culture) of Caco-2 cells, the sulfation of cell layer glycosaminoglycans increased, whereas protein kinase C activity was concomitantly redistributed from the membrane to the cytosol. The protein kinase C activators, 4-phorbol 12-myristate, 13-acetate and 1,2-dioctanoyl-glycerol inhibited glycosaminoglycan sulfation. By contrast, 4-phorbol 12, 13 didecanoate was ineffective.These results suggest that membrane-bound PKC may exert a modulatory effect on glycosaminoglycan sulfation, and this effect is gradually attenuated as Caco-2 cell differentiation progresses.     

Human xylosyltransferases in health and disease

The xylosyltransferases I and II (XT-I, XT-II, EC 2.4.2.26) catalyze the transfer of xylose from UDP-xylose to selected serine residues in the proteoglycan core protein, which is the initial and ratelimiting step in glycosaminoglycan biosynthesis. Both xylosyltransferases are Golgi-resident enzymes and transfer xylose to similar core proteins acceptors. XT-I and XT-II are differentially expressed in cell types and tissues, although the reason for the existence of two xylosyltransferase isoforms in all higher organisms remains elusive. Serum xylosyltransferase activity was found to be a biochemical marker for the assessment of disease activity in systemic sclerosis and for the diagnosis of fibrotic remodeling processes. Furthermore, sequence variations in the XT-I and XT-II coding genes were identified as risk factors for diabetic nephropathy, osteoarthritis or pseudoxanthoma elasticum. These findings point to the important role of the xylosyltransferases as disease modifiers in pathologies which are characterized by an altered proteoglycan metabolism. The present review discusses recent advances in mammalian xylosyltransferases and the impact of xylosyltransferases in proteoglycan-associated diseases. Received 9 February 2007; accepted 5 March 2007     

海葵等四种动物粘多糖碱提取的比较研究

采用碱提取法从绿疣海葵等4种海洋无脊椎动物中提取酸性粘多糖，其粗品产率分别为：绿疣海葵9．9％。绒毛近方蟹4．9％，毛肤石鳖4．3％，平背蜞3．6％．用蒽酮比色法和酚一硫酸法测定产品糖含量。考马斯亮蓝法测定蛋白质含量．醋酸纤维素薄膜电泳显示粘多糖的电泳迁移率相似，海葵粘多糖与甲苯胺蓝染色呈蓝色，绒毛近方蟹、平背蜞粘多糖呈紫色．     

Hyaluronan

The polysaccharide hyaluronan is an essential component of the vertebrate extracellular matrix and also produced by viruses, bacteria and fungi. Although the hyaluronan polymer is simply a disaccharide that repeats many thousands of times, it has an amazing array of biological functions and medical uses. For example, it is an efficient space filler that maintains hydration, serves as a substrate for assembly of proteoglycans and cellular locomotion, regulates cellular function and development, and is involved in tumor progression, inflammation and wound healing. Its physical properties and biocompatibility also make it of considerable importance in the development of engineered tissue, biomaterials and in clinical applications. Received 23 January 2007; received after revision 25 February 2007; accepted 22 March 2007     

The potency of heparin-like activity of glycosaminoglycans released by human endothelial cells in culture

Summary Glycosaminoglycans isolated from culture medium conditioned by human endothelial cells showed heparin-like antithrombin III cofactor activity measured by Xa inhibition. Their activity was relatively weak, 0.1% of the potency of heparin, but was approximately 5-fold more potent than that of glycosaminoglycans derived from vascular smooth muscle cells.     

The never-ending story of peptide O-xylosyltransferase

In a journey lasting 40 years from the first reports on its activity in the 1960s to its purification and the cloning of relevant complementary DNAs, peptide O-xylosyltransferase has finally arrived at the same point as many other enzymes. This enzyme, whose systematic name is UDP--D-xylose:proteoglycan core protein -D-xylosyltransferase (EC 2.4.2.26), catalyses the first step in the biosynthesis of chondroitin, dermatan and heparan sulphates in the endoplasmic reticulum and/or the cis-Golgi cisternae. Analyses of their primary structure show that peptide O-xylosyltransferases are members of glycosyltransferase family 14 and so are homologous to 1,6-N-acetylglucosaminyltransferases involved in O-glycan and poly-N-acetyllactosamine branching. Furthermore, vertebrates appear to have two rather similar genes encoding xylosyltransferase I and xylosyltransferase II, but enzymatic activity was only detected for a recombinant form of the first isoform. On the other hand, Caenorhabditis and Drosophila have each only one peptide O-xylosyltransferase gene. In the worm sqv-6 mutant, a mutation of the xylosyltransferase gene is associated with defective vulval morphogenesis, indicative of the importance of the glycosaminoglycan chains of proteoglycans in animal development. There remain, however, open questions, for instance, on the enzymes intracellular localisation and structure-function relationships.Received 11 July 2003; received after revision 4 September 2003; accepted 24 September 2003