超滤膜技术在多糖提取方面的应用

超滤膜技术广泛应用于各类多糖的分离、浓缩、纯化等研究中,包括中药药源多糖如灵芝多糖、大黄多糖、六味地黄汤多糖、黄芪多糖、紫芝多糖、人参多糖,海洋活性多糖如鲨鱼软骨粘多糖、褶纹冠蚌多糖、紫菜多糖、褐藻糖胶、卡拉胶,发酵多糖如蜜环菌菌索多糖、PS-9415发酵液多糖、冬虫夏草多糖,食用植物多糖如茶多糖、香菇多糖、金针菇多糖、芦荟多糖、枸杞多糖等.采用超滤膜技术处理多糖具有收率高、不易破坏多糖的生物活性、能耗低等特点,适于工业化生产.     

海藻多糖生物活性及分子修饰

简要介绍了近年来有关海藻多糖抗病毒、抗肿瘤、免疫促进、免疫抑制等生理活性的最新研究 ,重点介绍了不同种类海藻多糖的不同生理活性机理的研究进展。对多糖与生理活性之间的构效关系进行了阐述 ,在构效关系基础上进行多糖分子结构修饰是提高海藻多糖生理活性、降低毒副作用的有效手段。进一步介绍了目前多糖分子修饰常用方法 ,并对修饰后分子的生理活性改变进行了阐述。     

Fluorescent derivatization of polysaccharides and carbohydrate-containing biopolymers for measurement of enzyme activities in complex media

Fluorescence derivatization provides a means of tracing the dynamics of polysaccharides even in the presence of high concentrations of other organic compounds or salts. A method of labeling polysaccharides with fluoresceinamine was extended to polysaccharides of a wide range of chemical composition, and alternative means of preparation were established for polysaccharides not initially amenable to column chromatography. The polysaccharides were activated with cyanogen bromide, coupled to fluoresceinamine, and separated from unreacted fluorophore via gel filtration chromatography or dialysis. Since the resulting derivatized polysaccharides proved to be stable to further physical and chemical manipulation, methods were also developed for re-activation and labeling with a second fluorophore, as well as for tethering the labeled polysaccharides to agarose beads. As an example of the application of this approach, five distinct fluorescently-labeled polysaccharides (pullulan, laminarin, xylan, chondroitin sulfate, and alginic acid) were used to investigate the activities and structural specificities of extracellular enzymes produced in situ by marine microbial communities, providing a means of measuring specifically the activities of endo-acting extracellular enzymes and avoiding use of low molecular mass substrate proxies. These labeled polysaccharides could be used to explore the dynamics of polysaccharides in other types of complex media, as well as to investigate the activities and specificities of endo-acting enzymes in other systems.     

Microbial polysaccharides with actual potential industrial applications

The microbial polysaccharides reviewed include xanthan gum, scleroglucan, PS-10, PS-21 and PS-53 gums, polysaccharides from Alcaligenes sp., PS-7 gum, gellan gum, curdlan, bacterial alginate, dextran, pullulan, Baker's Yeast Glycan, 6-deoxy-hexose-containing polysaccharides and bacterial cellulose. Factors limiting the commercial potential of certain microbial polysaccharides such as availability, rheological properties, and polyvalency are outlined. The polysaccharides are classified according to their uses as viscosity-increasing agents and as gelling agents. A third category includes polysaccharides with specific applications such as tailor-made dextran and pullulan and polysaccharides used as substrates for the preparation of rare sugars. The difficulties encountered in development of a polysaccharide at the industrial level are pointed out.     

多糖硫酸化修饰和多糖硫酸酯的研究进展

硫酸多糖是一类糖羟基上带有硫酸根的多糖,包括从植物中提取的各种硫酸多糖、肝素、天然多糖的硫酸衍生物及人工合成的各种硫酸多糖。硫酸多糖具有抗病毒、抗肿瘤、抗凝血和增强免疫等生物活性,为提高中药多糖的生物活性,可通过硫酸化修饰的方法进行结构改造,获取多糖硫酸酯。本文就多糖的硫酸化修饰方法、多糖硫酸酯的生物学活性及其影响因素、作用机制和临床应用进行了综述。     

The capsular polysaccharide of Bacteroides fragilis comprises two ionically linked polysaccharides.

Recently, we have shown that the capsular polysaccharide of Bacteroides fragilis NCTC 9343 is composed of an aggregate of two discrete large molecular weight polysaccharides (designated polysaccharides A and B). Following disaggregation of this capsular complex by very mild acid treatment, high resolution NMR spectroscopy demonstrated that polysaccharides A and B consist of highly charged repeating unit structures with unusual substituent groups (Baumann, H., Tzianabos, A. O., Brisson, J.-R., Kasper, D.L., and Jennings, H.J. (1992) Biochemistry 31, 4081-4089). Presently, we report that the capsular polysaccharide of B. fragilis represents a complex structure that is formed as a result of ionic interactions between polysaccharides A and B. Electron microscopy of immunogold-labeled organisms (with monoclonal antibodies specific for polysaccharides A and B) demonstrated that the two polysaccharides are co-expressed on the cell surface of B. fragilis. We have shown that the purified capsule complex is made up exclusively of polysaccharide A and polysaccharide B (no other macromolecular structure was detected) in a 1:3.3 ratio and that disaggregation of this complex into the native forms of the constituent polysaccharides could be accomplished by preparative isoelectric focusing. Structural analyses of the native polysaccharides A and B showed that they possessed the same repeating unit structures as the respective acid-derived polysaccharides. The ionic nature of the linkage between polysaccharides A and B was demonstrated by reassociation of the native polysaccharides to form an aggregated polymer comparable to the original complex. The distinctive composition of this macromolecule may provide a rationale for the unusual biologic properties associated with the B. fragilis capsular polysaccharide.     

绵马贯众多糖超声提取工艺优化及抗氧化活性分析

绵马贯众是中国传统常用中药,本研究以温度、时间、超声功率、液料比为影响因子,多糖得率为评价指标,通过响应面法优化超声辅助提取绵马贯众多糖的工艺条件,同时测定其基本理化性质及抗氧化活性。研究结果表明,绵马贯众多糖的最佳提取工艺条件为:温度64℃、时间60 min、超声功率210 W、液料比27 mL/g。此时多糖得率为9.57%,与预测值接近。理化性质分析表明绵马贯众多糖为含少量蛋白的酸性多糖。体外抗氧化研究表明绵马贯众多糖具有很强的DPPH自由基清除活性,IC50值为0.29 mg/mL;较好的羟基自由基清除活性,其IC50值为1.10 mg/mL;对DNA的氧化损伤有显著的保护作用。绵马贯众多糖可以作为一种潜在的抗氧化剂应用于食品和化妆品等领域。     

聚酰胺树脂分离纯化芦荟多糖的研究

文章采用聚酰胺吸附树脂,采用水、0．2M／LNaCl溶液、5％NaOH水溶液为洗脱剂梯度洗脱分离纯化,得到了三个芦荟多糖组分,通过IR、UV、GC等手段对其进行了分析。以甘露糖为标准,采用硫酸．苯酚法,测得水洗和NaOH水溶液洗脱所得多糖含量分别为90．10％和93．28％;以木糖、甘露糖、葡萄糖、半乳糖为单糖标准的GC分析结果显示：水洗所得多糖主要以甘露糖为主,同时含有少量的葡萄糖。     

Changes in Morphology of J774.1 Macrophage-like Cells and Release of Prostaglandin E2 Induced by Bacterial Acidic Polysaccharides

In an attempt to finding polysaccharides with immunostimulating activity, we isolated 14 bacteria that produced polysaccharides from soil. The polysaccharides produced by these bacteria and by strains kept in this laboratory and commercial polysaccharides were tested for ability to activate J774.1 macrophage-like mouse cells. Acidic polysaccharides, especially those from the newly isolated bacteria, induced spreading of the cells and release of prostaglandin E₂ from the cells, which are manifestations of a state of activation. The prostaglandin E₂-releasing activity of the polysaccharides was 1/10 to 1/20 on a weight basis of that of Escherichia coli lipopolysaccharide, a potent immunostimulant.     

Isolation and structural studies of glucans from Phytophthora parasitica

Several polysaccharides have been isolated from the cell walls of Phytophthora parasitica, a phytopathogenic fungus of carnation. The crude polysaccharides were fractionated by successive chromatographies on DEAE-cellulose, Sephadex G-25, concanavalin-A-Sepharose and Sephadex G-200 columns. The neutral polysaccharides consist of a mixture of beta(1----3, 1----6)-D-glucans whose relative molecular masses varied from 9000 to about 200 000. All these polysaccharides have a main chain of beta(1----3)-linked D-glucose residues. They differ by the presence of 1----6 branched chains consisting of D-glucose and D-Glc-(1----3)-D-Glc, for the lowest molecular mass polysaccharides or D-Glc-(1----3)-D-Glc-(1---3)-D-Glc for the highest molecular mass polysaccharides.     

The polysaccharides from Ganoderma lucidum: Are they always inhibitors on human hepatocarcinoma cells?

The antitumor activity of intracellular polysaccharides from submerged fermentation of Ganoderma lucidum was investigated focusing on the inhibition on human liver cancer cells. The polysaccharides inhibited human hepatocarcinoma cell HepG2 during earlier phase with lower dosage but obviously became less functional in later phase regardless of the dosage applied. However, apoptosis of the drugged HepG2 cells appeared in later incubation phase with high dosage, and the apoptosis could be enhanced by supplemental dose of the intracellular polysaccharides. Nevertheless, the intracellular polysaccharides inhibited other human hepatocarcinoma cells such as BEL-7402 and Huh-7 but luckily stimulated human normal liver cell L02 only in a positive dose- and time-dependent manner; so did the sulfated extracellular polysaccharides when it inhibited HepG2 and L02 cells. However, the toxicity of sulfated extracellular polysaccharides to L02 cells can be eliminated by the intracellular polysaccharides.     

Histochemical demonstration of proteins, lipids and polysaccharides in Japanese monkey oocytes

A histochemical study of proteins, lipids and polysaccharides was carried out in the oocytes of Japanese monkey (Macaca fuscata) during development of follicles. There were a small number of protein granules reactive to acrolein-Schiff in the cytoplasm of oocytes from primordial, secondary and vesicular follicles, while there were no lipid droplets, granules of neutral polysaccharides or acid polysaccharides in the cytoplasm. Proteins reactive to acrolein-Schiff, neutral polysaccharides reactive to periodic acid-Schiff and acid polysaccharides stainable with alcian blue were observed in the zona pellucida of the oocytes of secondary and vesicular follicles. The zona pellucida contained sudanophilic lipids composed of neutral fats and lipoids, besides the proteins and polysaccharides.     

非生物因素对藻类胞外多聚糖含量影响

本文从研究铜绿微囊藻表型转换机制的需要出发,综述了非生物因素对藻类胞外多聚糖含量的影响.很多藻类的胞外多聚糖分泌量与环境中主要营养盐比例之间存在着一定的响应关系,在高碳氮比或高碳磷比条件下,即在氮不足或磷不足时,藻类光合作用固定的有机物质主要以不含氮磷的碳水化合物形式存在,胞内碳水化合物的过量累积导致其逐步向胞外转移释放,使得胞外多聚糖含量显著升高.在碳氮代谢不平衡的情况下,胞外多聚糖充当了接收过剩固定碳的汇.对于一些藻类,不同光谱、光强和光周期均可影响其胞外多聚糖的合成与分泌.温度对藻类胞外多聚糖的产生也有一定影响.由于胞外多聚糖在藻细胞相互粘结形成群体上发挥着重要作用,通过调控相关非生物因素使得铜绿微囊藻胞外多聚糖产量增加可能有助于在室内模拟铜绿微囊藻的群体形成.     

平菇菌粗多糖的抗氧化活性研究

采用深层发酵技术生产平菇粗多糖,时其清除DPPH自由基、羟自由基的能力、铁离子螯合能力以及还原力进行了比较分析。结果表明：菌丝体粗多糖和发酵液粗多糖均具有较强的抗氧化能力,但2种多糖的抗氧化能力存在差异;茵丝体粗多糖清除DPPH自由基的能力较强,其EC。。值为2．20mg／mL;发酵液粗多糖清除羟自由基的能力、铁离子螯合能力以及还原力较强,其EC50值分别为0．72mg／mL、3．32mg／mL和7．91mg／mL。在一定的浓度范围内,多糖的浓度增加,其抗氧化能力也随之增强,呈量效依赖关系。     

多糖与肠道菌群相互作用及其构效关系研究进展

肠道菌群是一个复杂的生态系统,影响宿主的饮食、疾病发展、药物代谢和免疫系统调节等诸多生理方面。多糖广泛存在于动物、植物及微生物中,具有多种生理活性。肠道菌群与多糖相互作用,消化难以消化的多糖,多糖作为肠道菌群的重要能量来源,促进益生菌增殖。肠道菌群紊乱导致疾病的发生,多糖通过调节肠道菌群改善疾病。随着“人类微生物组计划”的启动和国内外学者对肠道菌群的深入研究,多糖与肠道菌群的关系逐渐清晰,但多糖的结构与肠道菌群之间的关系还有待进一步探究。因此,本文综述了多糖与肠道菌群的相互作用,并通过调节肠道菌群的组成来改善疾病,以及从多糖的分子量、糖苷键、单糖组成三方面探讨多糖与肠道菌群的构效关系,同时对未来研究的方向进行展望,以期为治疗疾病的深入研究提供重要参照和建议。     

Labeling and chemistry of grapefruit pectic substances

The labeling of a number of polysaccharides found in grapefruit (Citrus paradisi) was achieved by feeding labeled myo-inositol to ripening grapefruit through their cut fruit stem, and allowing 4 days for the metabolism of label. The pectic polysaccharides were isolated by successive extraction of the labeled grapefruit with 80% ethanol, chloroform-methanol (1:1) and finally with 0.2 M Na₂ EDTA to solubilize pectic polysaccharides. The incorporation of label from myo-inositol into galacturonosyl, arabinosyl, xylosyl and galactosyl residues of pectic polysaccharides via myo-inositol oxidation pathway was demonstrated. Ion exchange chromatography of these labeled pectic polysaccharides using DE-52 cellulose resulted in the elution of eight totally or partially resolved polysaccharides with increasing salt concentration. The results suggest that, like other plant tissues, the myo-inositol oxidation pathway is also operative in ripening grapefruit and this metabolic pathway could be successfully utilized to achieve labeling of a number of pectic polysaccharides.     

Extraction of polysaccharides and the antioxidant activity from the seeds of Plantago asiatica L

The extraction conditions of polysaccharides from Plantago asiatica L. seeds were investigated. Four parameters affecting the polysaccharides extraction, extraction times, water to sample, extraction temperature and single extraction time, were determined by orthogonal experiments. Under the optimized conditions, the polysaccharides yield of P. asiatica L. seeds was 2.467%. The antioxidant activities of the polysaccharides were investigated. The reducing power of the polysaccharides was dose dependent, and the reducing capacity of the polysaccharides was inferior to butylated hydroxytoluene, which is known to be a strong reducing agent. The scavenging rates of the polysaccharides on superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals were79.7% and 81.4%, at polysaccharides concentration of 0.75 mg/mL, respectively, a scavenging rates approximately similar to that of 0.75 mg/mL ascorbic acid (83.5% and 85.1%, respectively). Furthermore, it exhibited a moderate concentration-dependent ABTS radical scavenging activity, ferrous ion chelating potency and H₂O₂ scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Semen Plantaginis.     

Comparative characterization of polysaccharide fractions in grapes]

Different methods of isolating polysaccharides from grapes were evaluated with respect to the three indictrial grape varieties Traminer pink, Rkatsiteli, Cabernet-Sovinjon. Hot water extration was shown to be the best method in the isolation of water-soluble polysaccharides in primary wine-making. The qualitative and quantitative composition of the isolated polysaccharides was found to depend on the method of isolating polysaccharide fractions. The polysaccharides of grapes were heterogeneous in their molecular weight. The results of periodate oxidation of high molecular weight carbohydrates suggest a branched structure of polymers of water-soluble polysaccharides of grapes.     

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。     

Polysaccharide Responsiveness Is Not Biased by Prior Pneumococcal-Conjugate Vaccination

Polysaccharide responsiveness is tested by measuring antibody responses to polysaccharide vaccines to diagnose for humoral immunodeficiency. A common assumption is that this responsiveness is biased by any previous exposure to the polysaccharides in the form of protein-coupled polysaccharide vaccines, such as those used in many childhood vaccination programmes.To examine this assumption, we investigated the effect of protein-coupled polysaccharide vaccination on subsequent polysaccharide responsiveness.HIV-infected adults (n = 47) were vaccinated twice with protein-coupled polysaccharides and six months later with pure polysaccharides. We measured immunoglobulin G responses against three polysaccharides present in only the polysaccharide vaccine (non-memory polysaccharides) and seven recurring polysaccharides (memory polysaccharides). Responsiveness was evaluated according to the consensus guidelines published by the American immunology societies.Impaired responsiveness to non-memory polysaccharides was more frequent than to memory polysaccharides (51% versus 28%, P = 0.015), but the individual polysaccharides did not differ in triggering sufficient responses (74% versus 77%, P = 0.53). Closer analysis revealed important shortcomings of the current evaluation guidelines. The interpreted responseś number and their specificities influenced the likelihood of impaired responsiveness in a complex manor. This influence was propelled by the dichotomous approaches inherent to the American guidelines. We therefore define a novel more robust polysaccharide responsiveness measure, the Z-score, which condenses multiple, uniformly weighted responses into one continuous variable. Using the Z-score, responsiveness to non-memory polysaccharides and memory-polysaccharides were found to correlate (R² = 0.59, P<0.0001).We found that polysaccharide responsiveness was not biased by prior protein-coupled polysaccharide vaccination in HIV-infected adults. Studies in additional populations are warranted.