南极菌Psychrobacter sp.B-3胞外多糖化学特征及其对番茄抗氧化酶的诱导作用研究

Chemical Characteristics of Exopolysaccharides in Antarctic Bacterium Psychrobacter sp. B-3 and Its Induction for Antioxidative Enzymes in Lycopersicon esculentum

以B-3多糖诱导番茄叶,采用试剂盒测定其对番茄叶抗氧化酶活性的影响,并对南极菌B-3胞外糖的分子量、单糖组成等化学特征进行了初步分析。结果表明,不同质量浓度的B-3在诱导不同时间后,均能提高番茄各抗氧化酶的活性。0.5%的B-3多糖诱导24h过氧化氢酶(CAT)活性最高;0.5%的B-3多糖作用48h对超氧化物歧化酶(SOD)和谷胱甘肽S-转移酶(GST)的诱导效应最佳;0.8%B-3多糖诱导48h过氧化物酶(POD)和谷胱甘肽过氧化物酶(GSH-PX)酶活达到峰值。B-3多糖对5种抗氧化酶的最佳诱导效果均极显著(P<0.01)地高于对照组,与相同条件下0.5%的壳聚糖(COS)诱导效果相比,除对CAT酶的诱导作用低于0.5%的COS外(P<0.05),对其它4个酶的诱导效果均与0.5%壳聚糖无显著差异(P>0.05)。B-3胞外糖经高效凝胶渗透色谱测定其分子量为2112Da,气相色谱分析其中性糖由甘露糖和葡萄糖两种单糖组成。样品中硫、糖醛酸和氨基糖的含量分别为:21.6%,14.9%和3.5%。

The leaves of Lycopersicon escylentum are induced by the B-3 polysaccharides, and the activities of the antioxidant enzymes from the leaves are measured by measn of the kit. The chemical characteristics such as the molecular weight, sugar composition of the exopolysaccharides from Antarctic bacterium B-3 are analyzed. It is shown in the analysis results that the B-3 polysaccharides with different concemtrations and different durations for the induction are helpful to improve the antioxdant enzyme activites. The activities of catalase（CAT） induced for 24 h by the B-3 polysaccharides with 0. 5% concentration become the strongest, the activities of superoxide dismutase（SOD） or glutathione st-stransferase（GST） induced for 48 h are the strongest, and the activities of peroxidase（POD） or GSH-PX induced for 48 h by the B-3 polysaccharides with the 0.8% eoncentraction reaches the strongest. The respective optimal activites of the 5 antioxidant enzymes are significantly （P〈0.01） better than the control experimental groups. In comparison with the 0.5% chitosan（COS） effects on the induction for the 4 enzymes （exept CAT） under the same experimental conditions, the polysaccharides effects （P〉0.05） are similar to the chitosan with the only exception for CAT in which the induction is less strong than chitosan （P%0.05）. The B-3 exopolysaccharides molecular weight is 2 112Da, as measured by means of HPLC. It is composed of mannose and glucose as analyzed by means of gas chromatograph spectroscopy. The contents of ester sulfate, uronic acid and amino sugar of B-3 are 21.6%, 14.9% and 3.5% respectively.