桃胶多糖的化学研究及其应用

毛桃(Prunus persica (L.) Batsch)是我国普遍裁培的一种果树。在桃树致病或受伤处会有桃胶(Peach gum)分泌。在一般情况下，天然桃胶是很难溶于水的，因此限制了它的使用。本文首次通过碱溶后，以快速沉淀的方法来降低桃胶的局部结晶度，使得桃胶能较顺利地溶解于冷水中。并提出了由于桃胶对金属镁的强络合作用而影响了桃树的正常生长这一推测。 桃胶经碱溶纯化制得钠型胶，再用阳离子交换树脂处理得氢型胶。用不同的方法处理桃胶后，桃胶红外光谱的结构特征吸收方才显示出来。钠型胶具840Cm-1的红外吸收;氢型胶具890Cm-1、1730cm-1的红外吸收;甲基化后的桃胶具810Cm-1、870Cm-1、890Cm-1的红外吸收。桃胶的比旋光度为负值。核磁共振证明桃胶多糖中，α-和β-甙键共存。碱溶纯化的桃胶多糖经凝胶色谱和超速离心证明为单一物质。 桃胶多糖不具还原性。经气相层析和比色法分析，桃胶中D-葡萄糖醛酸(包括4-甲氧基-D-葡萄糖醛酸）、D-半乳糖、D-木糖、D-甘露糖、L-阿拉伯糖、L-鼠李糖含量分别为10%、30%、11%、1.3%、45%、2%。18C-NMR和甲基化分析，证明桃胶大分子链是高度支链化的。且阿拉伯糖和半乳糖在大分子结构中有呋喃环和吡喃环两种形式共存。桃胶按物理性状，可分为两种。它们仅仅是在分子量和水溶液中的粘度不同，分子量( Mw)为342.9万和416.9万，特性粘度(η)为0.425dl/g和0.866dl/g。但在化学成分及结构特征上是相似的。以甘油为增塑剂，能增加桃胶成膜后的柔韧性。

水母雪莲毛状根培养及黄酮类化合物生物合成的调控

水母雪莲(Saussurea medusa Maxim)为菊科凤毛菊属植物,是名贵中药材,其主要活性成分为黄酮类化合物。为解决雪莲资源匮乏，本文开展了利用水母雪莲毛状根培养生产黄酮类活性成分的研究。 在1/2MS液体培养基上研究了不同理化因子对水母雪莲毛状根生长和黄酮类化合物生物合成的影响。实验结果表明:氮源总浓度（包括NH4+和NO3-）为30 mmol/L;NH4+/NO3-比例为5:25;2 %蔗糖和3 %葡萄糖组合;0.5 mg/L GA3和0.5 mg/L IBA;pH 5.8;18 h/d的光照（光强为3500 Lux）;24℃;摇床转速为100 rpm的条件有利于毛状根生长及黄酮类化合物的生物合成。在此培养条件下，经过21 d的培养毛状根生长量达到12.8 g/L（DW），黄酮类化合物合成量为1922 mg/L，即黄酮类化合物含量占毛状根干重的15 %，约为野生水母雪莲植株干重黄酮类化合物含量的25倍。 用MJ和SA两种诱导子分别处理水母雪莲的毛状根，适宜条件下它们均能使毛状根中黄酮类化合物的产量得到提高。实验发现，在水母雪莲毛状根培养过程中，MJ抑制其生长，但提高了黄酮类化合物在毛状根中的百分含量;SA降低了黄酮类化合物在毛状根中的百分含量，但促进其生长。诱导子的作用效果与诱导子的浓度和添加时间有关。在延迟期后期添加浓度为0.02 mmol/L的MJ时黄酮类化合物产量达到 849 mg/L，比对照（633 mg/L）提高34.1 %;在指数生长期中期添加浓度为0.03 mmol/L的SA时，黄酮类化合物产量达到968 mg/L，比对照（633 mg/L）提高52.9 %。在指数生长期前期同时添加浓度为0.02 mmol/L的MJ 和0.03 mmol/L的SA，黄酮类化合物的产量为1125 mg/L，比对照（633 mg/L）提高77.7 %。 另外采取热水、碱提取，乙醇沉淀获得水母雪莲毛状根多糖。进一步用α-萘酚—浓硫酸法进行定性、定量分析，测得水母雪莲毛状根中水溶性多糖与碱溶性多糖的含量分别为2.453 %和3.391 % 。

多糖化合物抗HIV活性及应用

　多糖类化合物种类繁多,许多多糖化合物在体内或体外表现出良好的抗HIV 活性,多糖能 够作用于HIV 复制周期的多个环节,影响tat 、gp120、RT 等多个病毒蛋白的功能。目前,已有多糖 被用于杀微生物剂、抗病毒辅助治疗、抗机会性感染等临床研究中,多糖在临床上存在抗凝血活 性、生物利用度低等问题,但丰富的多糖类化合物因其作用多效性仍有广阔的抗HIV 应用前景。

环境因子对铜绿微囊藻7820胞外多糖的影响

研究了多种环境因子对铜绿微囊藻7820可溶性胞外多糖(extracellular polysaccharide,EPS)合成的影响.在18 d内,较高浓度的NO3-,较高的pH和光强,均显著提高了EPS的合成,其中,NO3-对EPS的合成影响最大,其最大产率为5.255μg.L-1.d-1.而KH2PO4,CaCl2,MgSO4等大量元素、以及微量元素FeCl3和EDTA对EPS的合成无明显影响;除在实验后期20℃时EPS有较大增加外,温度对其无明显影响.在各种环境因子影响下,EPS产量均随时间延长而增加

Effects of Cd2+ and Pb2+ on the substrate biofilms in the integrated vertical-flow constructed wetland

The effects of single Cd2+ and Pb2+, and combined Cd2+ and Pb2+ on dehydrogenase activity and polysaccharide content of the substrate biofilms in the integrated vertical-flow constructed wetland (IVCW) were studied. Dehydrogenase activities decreased linearly with the increasing concentrations of Cd2+ and Pb2+ at different times (6, 24, 72, and 120 h). The activities at both 6 and 24 h were significantly higher than that at 72 and 120 h in the case of single and combined treatments. The single Cd2+ and Pb2+ treatments significantly inhibited dehydrogenase activities at concentrations in excess of 20 mu mol/L Cd2+ and 80 mu mol/L Pb2+, respectively. The inhibitory effect of Cd2+ was much greater than that of Pb2+. At the same time, the combined treatment of Cd2+ and Pb2+ Significantly inhibited dehydrogenase activities at all five concentrations studied and the lowest combined concentration was 1.25 mu mol/L Cd2+ and 5 mu mol/L Pb2+. A synergistic effect of Cd2+ and Pb2+ was observed. On the other hand, polysaccharide contents varied unpredictably with the increasing concentrations of Cd2+ and Pb2+ and extended experimental time. There were no significant statistical differences within the range of concentration and time studied, whether singly or in combination. These results implied that the effects of heavy metals on biofilms should be a concern for the operation and maintenance of constructed wetlands.

Effects of nutrients on the substrate biofilms in the integrated vertical-flow constructed wetland

A L9 orthogonal array design involving 3 factors (C6H12O6, KNO3 and NaH2PO4) and 3 levels for each (C6H12O6: 0.2, 0.4 or 0.8 g/L; KNO3: 0.4, 0.8 or 1.6 g/L, NaH2PO4: 0.05, 0.1 or 0.2 g/L), was used to study the effects of nutrients on dehydrogenase activity and polysaccharide content of substrate biofilms in the integrated vertical-flow constructed wetland (IVCW). Results showed that C6H12O6 and KNO3 were the main factors for dehydrogenase activity and polysaccharide content of biofilms, respectively. The combinations of three nutrients at different concentrations had different effects on dehydrogenase activity and polysaccharide content of biofilms. The optimal combination for dehydrogenase activity was obtained by locating the concentrations Of C6H12O6, KNO3 and NaH2PO4 at 0.2, 0.8 and 0.05 g, and the optimal combination for polysaccharide content was obtained by locating the concentrations Of C6H12O6, KNO3 and NaH2PO4 at 0.2, 0.4 and 0.2 g/L, respectively. The corresponding maximum activity and polysaccharide content were 5.40 mu g TF/g substrate/12 h and 3454.6 mu g/g substrate, respectively. These results would provide the laboratory foundation for optimizing the purification function of the wetland systems.

Regulation by hetC of genes required for heterocyst differentiation and cell division in Anabaena sp strain PCC 7120

Unlike those of the wild-type strain, proheterocysts of the Anabaena sp. strain PCC 7120 hetC strain keep dividing. ftsZ, the most critical cell division gene, is up-regulated in hetC proheterocysts. Heterocyst differentiation genes hglD, hglE, patB, nijB, and xisA are no longer expressed in the hetC mutant. hetC also regulates the expression of patA, a pattern formation gene.

Cloning and characterization of the gene for UDPGlc dehydrogenase from the cyanobacterium, Microcystis aeruginosa FACHB 905

Using degenerate primers based on conserved regions of the UDP-glucose dehydrogenase (UDPGDH) gene, an initial 476-bp DNA fragment was amplified from the water-bloom forming cyanobacterium, Microcystis aeruginosa FACHB 905. TAIL-PCR and ligation-mediated PCR were used to amplify the flanking regions to isolate an about 2.5-kb genomic DNA fragment. Sequence analysis revealed an ORF encoding a putative 462 amino acid protein, designated Mud for Microcystis UDPGDH. The Mud amino acid sequence is closely related to UDPGDH sequences from cyanobacterium Synechocystis PCC6803 (73% identity, 81% similarity), and bacterium Bacillus subtilis (51% identity and 67% similarity). The cloned mud gene was expressed in Escherichia coli using the pGEX-4T-1 fusion expression vector system to generate a GST-Mud fusion protein that exhibited UDPGDH activity. The cytosolic fraction of M aeruginosa FACHB 905 was subjected to Western analysis with an anti-Mud antibody, which revealed a single band of approximately 49 kD, consistent with the deduced molecular mass of the enzyme. The Mud protein could thus be characterized as a UDP-glucose dehydrogenase, which was a key enzyme for polysaccharide synthesis and has, for the first time, been studied in algae.

alr0117, a two-component histidine kinase gene, is involved in heterocyst development in Anabaena sp PCC 7120

Anabaena sp. PCC; 7120 was mutagenized by transposon Tn5-1087b, generating a mutant whose heterocysts lack the envelope polysaccharide layer. The transposon was located between nucleotides 342 and 343 of alr0117, a 918 bp gene encoding a histidine kinase for a two-component regulatory system. Complementation of the mutant with a DNA fragment containing alr0117 and targeted inactivation of the gene confirmed that alr0117 is involved in heterocyst development. RT-PCR showed that alr0117 was constitutively expressed in the presence or absence of a combined-nitrogen source. hepA and patB, the two genes turned on during wild-type heterocyst development, were no longer activated in an alr0117-null mutant. The two-component signal transduction system involving alr0117 may control the formation of the envelope polysaccharide layer and certain late events essential to the function of heterocysts.

A physico-chemical comparative study on extracellular carbohydrate polymers from five desert algae

Hydrodynamic properties of five newly isolated algal extracellular polysaccharides with putative adhesive properties are described, using a combination of size exclusion chromatography, total or 'multi-angle' laser light scattering and analytical ultracentrifugation. The respective polysaccharides had been extracted from four filamentous cyanobacteria: Microcoleus vaginatus, Scytonema javanicum, Phormidium tenue and Nostoc sp. and a coccoid single-cell green. algae Desmococcus olivaceus that had been separated from desert algal crusts of the Chinese Tegger Desert. SEC/MALLS experiments showed that the saccharides had, diverse-weight average molecular weights ranging from 4000 to 250,000 g/mol and all five showed either bi-modal or tri-modal molecular weight distribution profiles. Use of the Mark-Houwink-Kuhn-Sakurada (MHKS) scaling relationship between sedimentation coefficient and (weight average) molecular weight for the five samples, assuming a homologous conformation series revealed an MHKS b exponent of (0.33 +/- 0.04), suggesting a conformation between that of a stiff rod (b similar to 0.18) and a random coil (b similar to 0.4-0.5), i.e. a 'flexible rod' or 'stiff coil'. (C) 2003 Elsevier Ltd. All rights reserved.

Extracellular carbohydrate polymers from five desert soil algae with different cohesion in the stabilization of fine sand grain

Extracellular polymeric substances (EPS) from four filamentous cyanobacteria Microcoleus vaginatus, Scytonema javanicum, Phormidium tenue and Nostoc sp. and a coccoid single-cell green alga Desmococcus olivaceus that had been separated from desert algal crusts of Tegger desert of China, were investigated for their chemical composition, structure,and physical properties. The EPS contained 7.5-50.3% protein (in polymers ranging from 14 to more than 200 kD, SDS-PAGE) and 16.2-46.5% carbohydrate (110-460 kD, GFC). 6-12 kinds of monosaccharides, including 2-O-methyl rhamnose, 2-O-methyl glucose, and N-acetyl glucosamine were found. The main carbohydrate chains from M. vaginatus and S. javanicum consisted mainly of equal proportion of Man, Gal and Glc, that from P. tenue consisted mainly of arabinose, glucose and rhamnose. Arabinose was present in pyranose form, mainly alpha-L 1 --> 3 linked, with branches on C4 of almost half of the units. Glucose was responsible for the terminal units, in addition of having some units as beta1 --> 3 and some as beta1 --> 4 linked. Rhamnose was mainly 1 --> 3 linked with branches on C2 on half of the units. The carbohydrate polymer from D. olivaceus was composed mainly of beta1 --> 4 linked xylose, galactose and glucose. The galactose part was present both in beta-pyranose and -furanose forms. Arabinose in alpha-L-furanose form was mainly present as 1 --> 2 and 1 --> 2, 5 linked units, rhamnose only as alpha 1 --> 3 and xylose as beta 1 --> 4. The backbone of the polysaccharide from Nostoc sp. was composed of beta-1 --> 4 linked xylose, galactose and glucose. Most of the glucose was branched on position C6, terminal glucose and 2-O-methyl glucose units are also present. The relationship between structure, physical properties and potential biological function is discussed. (C) 2003 Elsevier Ltd. All rights reserved.

Studies on polysaccharides from three edible species of Nostoc (Cyanobacteria) with different colony morphologies: Comparison of monosaccharide compositions and viscosities of polysaccharides from field colonies and suspension cultures

Hot water-soluble polysaccharides woe extracted from field colonies and suspension cultures of Nostoc commune Vaucher, Nostoc flagelliforme Berkeley et Curtis, and Nostoc sphaeroides Kutzing. Excreted extracellular polymeric substances (EPS) were isolated from the media in which the suspension cultures were grown. The main monosaccharides of the field colony polysaccharides from the three species were glucose, xylose, and galactose, with an approximate ratio of 2:1:1. Mannose was also present, but the levels varied among the species, and arabinose appeared only in N. flagelliforme. The compositions of the cellular polysaccharides and EPS from suspension cultures were more complicated than those of the field samples and varied among the different species. The polysaccharides from the cultures of N. flagelliforme had a relatively simple composition consisting of mannose, galactose, glucose, and glucuronic acid, but no xylose, as was found in the field colony polysaccharides. The polysaccharides from cultures of N. sphaeroides contained glucose (the major component), rhamnose, fucose, xylose, mannose, and galactose. These same sugars were present in the polysaccharides from cultures of N. commune, with xylose as the major component. Combined nitrogen in the media had no qualitative influence on the compositions of the cellular polysaccharides but affected those of the EPS of N. commune and N. flagelliforme. The EPS of N. sphaeroides had a very low fetal carbohydrate content and thus was not considered to be polysaccharide in nature. The field colony polysaccharides could be separated by anion exchange chromatography into neutral and acidic fractions having similar sugar compositions. Preliminary linkage analysis showed that 1) xylose, glucose, and galactose were 1-->4 linked, 2) mannose, galactose, and xylose occurred as terminal residues, and 3) branch points occurred in glucose as 1-->3,4 and 1-->3,6 linkages and in xylose as a 1-->3,4 linkage. The polymer preparations from field colonies had higher kinematic viscosities than those from corresponding suspension cultures. The high viscosities of the polymers suggested that they might DE suitable for industrial uses.

气体水合物生成特性实验研究

实验研究了添加剂对甲烷气体水合物形成过程的影响。发现微量的表面活性剂降低了甲烷气体水合物在静止反应器中形成的诱导时间，并使水合物快速形成和生长，提高了水合物形成过程中的填充密度。阴离子表面活性剂（十二烷基硫酸钠）对水合物生长的促进作用比非离子表面活性剂（烷基多糖苷）强。液态烃环戊烷降低了水合物形成的诱导时间，但环戊烷不能提高水合物的填充密度。

西藏胡黄连和鸡矢藤的化学成分及黄芪多糖的提取工艺研究

本论文由四部分组成，前三部分为实验论文，第四部分为文献综述。第一、二部分分别报道了中药西藏胡黄连和鸡矢藤的化学成分研究结果。从两种药用植物中共分离和鉴定了32个化学成分，其中3个为新化合物。第三部分为黄芪多糖的提取工艺研究。第四部分概述了近年来植物多糖的研究进展。 第一章为西藏胡黄连化学成分研究。通过正、反相硅胶柱层析等分离方法从药用植物西藏胡黄连（Picrorhiza scrophulariiflora Pennell）的根茎中共分离纯化出7个化合物。运用MS、1H-NMR、13C-NMR、DEPT、HSQC和HMBC等现代谱学方法，结合理化分析对这些化合物的结构进行了分析鉴定。7个化合物中有两个是酚性的葡萄糖苷类成分：西藏胡黄连酚苷D (1)、4-O-β-D-(6-O-vanilloyl glucopyranosyl) vanillic acid (6)；四个苯乙基苷类化合物：plantamajoside (2)、plantainoside D (3)、西藏胡黄连苷A (4) 和西藏胡黄连苷F (5)；一个苯基小分子化合物：香豆酸甲酯 (7)。其中化合物1和5未见文献报道，确定为新化合物；化合物3为首次从该种植物中分到。 第二章为鸡矢藤化学成分研究。从鸡矢藤（Paederia scandense (Lour) Merrill）全草中分离出25个化合物，通过理化常数和波谱数据鉴定了它们的结构。25个化合物中包括一个蒽醌类成分：茜根定-1-甲醚 (1)；两个香豆素：异东莨菪香豆素 (2)和5-羟基-8-甲氧基吡喃香豆素 (3)；两个香豆素-木脂素化合物：臭矢菜素 B (4)和臭矢菜素 D (5)；一个木脂素：异落叶松树脂醇 (6)；两个黄酮：diadzein (7)和蒙花苷 (8)；三个三萜类化合物：齐墩果酸 (9)、乌苏酸 (10)和 3-O-β-D-吡喃葡萄糖基乌苏烷 (11)；三个甾体及其糖苷：b-谷甾醇 (12)、胡萝卜苷 (13)和(24R)-豆甾-4-烯-3-酮 (14)；六个小分子化合物：对羟基苯甲酸 (15)，咖啡酸 (16)，香豆酸 (17)，丁烯二酸 (18)，3,5-二甲氧基-4-羟基苯甲酸(19)，咖啡酸-4-O-β-D-吡喃葡萄糖苷(20)；五个环烯醚萜类化合物：鸡矢藤苷 (21)，鸡矢藤酸 (22)，鸡矢藤酸甲酯 (23)，saprosmoside E (24)和paederoside B (25)。其中化合物25未见文献报道，为新化合物。化合物1～8、11、14、15～20为首次从该化合物中分离得到。同时对鸡矢藤中环烯醚萜类化合物做了高效液相-串联质谱(HPLC-MSn)分析，探讨了这类化合物的质谱裂解规律。 第三章为黄芪多糖的提取工艺研究。首先确定了黄芪多糖含量的测定方法，并进行了方法学验证；其次探讨了黄芪中黄芪多糖的提取工艺，确定以酶法-Sevag法联用来去除黄芪多糖中的蛋白质，可使其提取物中黄芪多糖总含量达到70％以上。 第四章为近年来植物多糖的研究进展。主要包括植物多糖的提取纯化、多糖的定性定量检测方法、多糖的结构分析和多糖的药理活性。 This dissertation consists of four parts. The first and second parts reports the studies on the chemical constituents of medicinal plants of Picrorhiza Scrophulariiflora and Paederia scandens. The third part is about the extract technique of Astragalan Polysaccharide (APS). The last part reviews the progress of the studies on plant polysaccharides. 　 The first chapter is about the chemical constituents of P. Scrophulariiflora which is widely used as an important medicine to treat various immune-related diseases. A new phenyl glycoside, scrophenoside D (1) and a new phenylethyl glycoside, scroside F (5), together with five known compounds, plantamajoside (2), plantainoside D (3), scroside A (4), 4-O-β-D-(6-O-vanilloylglucopyranosyl) vanillic acid (6); and methyl-p-coumarate (7) were isolated from the stems of P. scrophulariiflora. Their structures were elucidated by spectroscopic and chemical methods. The second chapter is about the chemical constituents of medicinal herb of P. scandens. Twenty-five compounds were isolated and purified by normal and reversed phase silica gel column chromatography. By physicochemical properties and spectral analysis, their structures were identified as rubiadin-1-methylether (1), isoscopoletin (2), 5-hydroxyl-8-methoxyl-coumarin (3), cleomiscosin B (4), cleomiscosin D (5), isolariciresinol (6), diadzein (7), linarin (8), oleanolic acid (9), ursolic acid (10), 3-O-β-D-glucopyranosyloxyl-ursane (11), b-sitosterol (12), b-daucosterol (13), (24R)-stigmast-4-ene-3-one (14), p-hydroxyl-benzoic acid (15), caffic acid (16), coumaric acid (17), trans-butenedioic acid (18), 3,5-dimethoxyl-4-hydroxylbenzoic acid (19), caffeic acid 4-O-β-D-glucopyranoside (20), paederoside (21), paederosidic acid (22), paederosidic acid methyl ester (23), saprosmoside E (24), paederoside B (25). Among them, compound 25 is a new compound. Compounds 1～8、11、14、15～20 were isolated from this plant for the first time. Futhermore, we studied the HPLC-MSn analysis and investigation of fragmentation behavior of the sulfur-containing iridoid glucosides. The third chapter is about the extracting process of Astragalan Polysaccharide (APS). The method of the content determination is built. The optimum condition of extraction of polysaccharides from Radix Astragali is defined and the more effective way to remove protein is combined enzyme method with Sevag method, by which the content of polysaccharides extract can be up to 70%. The last part is a review of the research progress of the plant polysaccharides, which includes its extraction, isolation, purification, determination, structure analysis, and pharmacology.