【作者】 刘斌斌；

【导师】 浦铜良；

【作者基本信息】 兰州大学 ， 植物学， 2009， 硕士

【摘要】 研究发现,分布于甘肃省民勤县、临泽县的沙丘芦苇（phragmites communis Trin.）中含有一种多氨基芳香族化合物（polyamine aromatic compound,简称PAAC）,分子量为856Dalton,该化合物在其它三种生态型芦苇均未发现。为进一步研究其分子结构,实验通过柱层析手段,TLC和质谱分析技术对两地沙丘芦苇中的PAAC进行提取纯化和分析比对。结果显示两地沙丘芦苇的特有内含物是同一物质,并通过元素分析,红外光谱和H-NMR分析,确定该化合物分子式为C₄₂O₁₁H₍64_N8,不饱和度15。植物在逆境中很容易累积大量自由基而损伤生物分子。蛋白质在细胞内外广泛分布,极易受到自由基氧化。研究发现PAAC与芦苇抗逆性有关,并能与蛋白质结合。为证实PAAC对蛋白质的保护作用,本试验以水生芦苇（Phragmites communis Trin.）叶片为材料,提取可溶性蛋白,研究了PAAC对外源·OH引起的水生芦苇可溶性蛋白氧化损伤的影响;并用临氮二菲法测定了PAAC直接清除·OH的能力。研究结果表明,在0～25μmol/L范围内,随着PAAC浓度的增加,由·OH引起的蛋白质羰基含量明显减少,PAAC浓度达到25μmol/L后,蛋白质羰基减少逐渐减缓,当PAAC浓度达到40μmol/L,蛋白质羰基含量基本维持不变,说明在0～25μmol/L范围内,PAAC处理能有效减轻外源·OH引起的水芦可溶性蛋白氧化损伤程度。用临氮二菲法测定PAAC直接清除·OH能力的实验也表明PAAC在低浓度时能有效清除·OH,0.45mmol/L时清除率达到55.2%。通过实验可以证实生长于两地的沙丘芦苇所含有的该小分子物质是否同一物质,并对与该化合物的结构信息进一步了解;验证PAAC对蛋白质保护作用以及直接清除自由基的能力,这对揭示它作为相容性物质在芦苇抗逆中的作用及作用机理具有重要的理论价值和潜在的实用价值。更多还原

【Abstract】 Preliminary studies suggest the compound, only exists in the dune reed coming from Minqin and Linze of Gansu province. Our work demonstrate it is a special polyamine aromatic compound（PACC） associated with anti-stress and not exist in other three ecotype reeds（swamp reed, light salt meadow reed and heavy salt meadow reed）. We used three different techniques（TLC,H-NMR,IR） to analyse the structure of PACC from the reed of Minqin and Linze, and the results show they are identical, molecular weight 856Dalton. In addition, element analysis, ultra-red spectrum analysis and H-NMR analysis all demonstrate the molecular forum of this compound is C₄₂O₁₁H₆₄N₈ and the unsaturation is 15.To further investigate its antioxidant function in plant, experiments were design to identify its protection on protein against reactive oxygen species damage in vitro. Study was processed as followed procedures: first, damage model was constructed by addition of exogenous hydroxyl radical（·OH） on the salt-reed protein solution; second, different doses of PAAC were feeded to the damage system, respectively; third, the protein carbonyl of the solutions was estimated. In addition, a supplementary test was carried out to examine the direct scavenging capacity of PAAC based on the method of orthophenanthroline.Our data suggest PAAC can decrease the protein damage when treated with hydrol radical（·OH）, and this protection effect is related significantly with the concentration of PAAC. With PAAC concentration increasing from 0 to 25μmol/L, the carbonyl amount declined rapidly, but declined gradually in the range of 25 to 40μmol/L. This protection function of low concentration of PAAC was also confirmed by hydrol radical（·OH） removal experiment, the scavenging rate is 55.2% when PAAC concentration is 0.45mmol/L.更多还原