秸秆降解产物的仪器分析(二)——用气液色谱法测定稻草结构性多糖水解产物的化学成分

用气液色谱法对3种典型预处理(NaOH 处理、尿素处理和未处理)秸秆经不同前处理程序(乙醇(体积分数=80%)超声波浸提、中性洗涤、酸性洗涤和对照)后被硫酸水解的产物进行了分析和比较。结果表明,用乙醇(=80%)超声波浸提能有效地保持秸秆细胞壁结构性多糖的完整特征。此外,首次找到了在糖腈乙酰酯法制备单糖衍生物过程中控制葡萄糖和半乳糖不出杂峰(异构衍生物)的条件。针对影响肟化和乙酰化过程中的各种因素和条件进行了优化,并给出了一套快速、完整、适用的日常分析方法。

预处理改变稻草亚细胞结构的化学基础

以氢氧化钠、碳酸氢铵和尿素处理的稻草为研究对象，采用糖腈乙酰酯法和碱性硝基苯氧化法，分别测定了化学预处理前后稻草用80％乙醇浸提残渣中结构性多糖和木质素组分的变化．试验结果显示，化学预处理后稻草结构性多糖水解产物下降7．9％～17．7％；木质素组分中愈伤木基木质素下降31．9％～37．7％，对羟基苯基木质素下降16．6％～28．5％，紫丁香基木质素下降11．5％～16．8％，对香豆酸下降16．6％～26．3％，阿魏酸下降5．5％～11．1％．各组分下降幅度均以氢氧化钠处理最高．上述结果表明，化学预处理通过破坏木质素与结构性多糖、木质素单体之间的连接，导致细胞壁各层的木质素组分不同程度的下降是化学预处理后稻草亚细胞结构变化的化学基础所在．

Exploration for a Natural Selenium Supplement——Characterization and Bioactivities of Se-containing Polysaccharide from Garlic

A Se—containing polysaccharide(Se-GPS),with average molecular weight of 1.5×10~4 was isolated from Hubei Enshi garlic(Allium sativum L.)and purified by means of Sephadex G25 to G200 chromatographies.Its chemical homogeneity and composition were studied by optical rotation,HPLC and paper chromatographical methods.The abilities of scavenging active oxygen free radicals and inhibiting the damage of erythrocyte membrane by SiO_2 were established by spin trapping ESR studies.Se-GPS was shown to inhibit human cytomegalovirus by plague reduction assays and cytopathogenic effect tests.

Structure and Anti-influenza A(H1N1) Virus Activity of Three Polysaccharides from Eucheuma denticulatum

Three polysaccharides （EW, EH and EA） were prepared from a red alga Eucheuma denticulatum by sequential extraction with cold water, hot water and sodium hydroxide water solution. Their monosaccharide compositions, relative molecular mass and structural characterization were determined by gas chromatography, high performance liquid chromatography, fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods. EW was hybrid l/k/v-carrageenan （701/17k/13v-car- rabiose）, EH was mainly t-carrageenan, and EA was mainly α-1,4-Glucan （88%） but mixed with small amount of t-carrageenan （12%）. The relative molecular mass ofEW, EH and EA was 480, 580 and 510kDa, respectively. The anti-influenza A （H1N1） virus activity of these three polysaccharides was evaluated using the Madin-Darby canine kidney cells model. EW showed good anti-H1N1 virus activity, its ICso was 276.5 μg mL-1, and the inhibition rate to H1N1 virus was 52% when its concentration was 250 μgmL-1. The ICs0 of t-carrageenan EH was 366.4 μgmL1, whereas EA showed lower anti-H1N1 virus activity （IC50〉430μgmL-1）. Available data obtained give positive evidence that the hybrid carrageenan EW from Eueheuma denticulatum can be used as potential anti-H1N1 virus inhibitor in future.

Graft Copolymerization of Acrylic Acid onto Fungal Cell Wall Structural Polysaccharide

Acrylic acid was graft-copolymerized onto Rhi. oryzae's cell wall structural polysaccharide directly and efficiently in aqueous solution with eerie ammonium nitrate as initiator. The maximal grafting percentage of 135.5% was obtained under the condition of [Ce4+]=5mmol·L-1, [AA]=lmol·L-1, T=60℃ and t=3h. Graft copolymerization was suggested to proceed through free radical reaction mechanism. Grafting occurred primarily on chitosan. Acrylic acid was also attempted to be grafted onto Asp. niger cell wall structural polysaccharide, and only 44.2% of grafting percentage was resulted.

Preparation and Biocompatibility of Porous Poly(vinylalcohol)-Glycosaminoglycan-Collagen Scaffold

This paper aims to prepare a PVA-GAG-COL composite with polyvinyl alcohol (PVA), glycosaminoglycan (GAG) and collagen (COL) by the method of freeze drying and to investigate the feasibility as a tissue engineering scaffold for tissue or organ repairing. In this study, SEM was used to observe the morphology. Biocompatibility was tested by cell culture with the extracted fluid of composite materials. Different proportional scaffolds could be obtained with different concentrations and alcoholysis degree of PVA. Different proportional scaffolds also had different porous structures. SEM proved that large amount of porous structure could be formed. Biocompatibility test showed that the extracted fluid of composite materials was nontoxic, which could promote the adhesion and proliferation of the fibroblast. Fibroblast could grow on the scaffold normally.A porous scaffold for tissue engineering with high water content can be fabricated by PVA, GAG and COL, which has excellent cell biocompatibility. The porous structure shows potential in tissue engineering and cell culture.

Microbial transformation of isoangustone A by Mucor hiemalis CGMCC 3.14114

Isoangustone A （1） is an isoprenylated flavonoid isolated from licorice. It has been reported to possess anti-microbial, anti-oxidative, anti-inflammatory, and anti-tumor activities. In order to increase its structural diversity, microbial transformation of 1 was conducted by Mucor hiemalis CGMCC 3.14114 to obtain three new compounds. By extensive NMR and MS spectroscopic analyses, their structures were identified as isoangustone A 7-O-glucoside （2）, isoangustone A 7-O-glucoside-4＇-O-sulfate （3）, and isoangustone A 7,3 ＇di-O-glucoside （4）, respectively. The major biotransformation reaction was glycosylation at C-7. Sulfation is rare for microbial transformation.