Under certain conditions algal alginates bind pinacyanol chloride in the form of dimers – this is the conclusion drawn from a uv/vis and circular dichroism (CD) spectroscopic study of aqueous solutions of the dye in ...Under certain conditions algal alginates bind pinacyanol chloride in the form of dimers – this is the conclusion drawn from a uv/vis and circular dichroism (CD) spectroscopic study of aqueous solutions of the dye in a 10-fold molar excess of the polysaccharide from different sources. With its easily detected features the dimer holds promise as a diagnostic tool for alginate conformational analysis. Binding of the strongly blue-shifted (maximum wavelength = 485 nm) dimer is probably mediated by the charged groups and involves guluronate units only. By using the peakFit program, the two overlapping excitonic absorption bands together with the optically inactive band resulted from the interaction of pinacyanol with a specific alginate concentration were separated. The standard Gibbs energy of the interaction was calculated as –27.02 kJ.mol–1. The dimers are sensitive against acid and divalent cations.展开更多
It is reported that fermentative liquids with various concentrations of La and Nd affect the fer- mentation of alginic acid from the strain 342 of Azotobacter vinelandii.The results are as follows:When the concentrati...It is reported that fermentative liquids with various concentrations of La and Nd affect the fer- mentation of alginic acid from the strain 342 of Azotobacter vinelandii.The results are as follows:When the concentration of La or Nd was up to 100 ppm,the cell growth is stimulated and the production of alginic acid is promoted.The La or Nd in concentration higher than 200 ppm or 150 ppm inhibits the fermentation, respectively.As the concentration range of La is 0～100 ppm or that of Nd is 0～150 ppm,the yield of fixed nitrogen increases,and the ratio of c_M to c_G(c_M/c_G)decreases with the raise of the concentration of La or Nd.When the concentration range of La is 100～400 ppm and that of Nd is 150～400 ppm,the conclusion is contrary to the above mentioned result.展开更多
目的制备分离不同聚合度的甘露糖醛酸寡糖单体,测定其体外抗氧化活性。方法采用微波辅助降解法,制备甘露糖醛酸寡糖混合物,采用Bio Gel P-6凝胶渗透色谱法对寡糖混合物进行分离纯化,得到7个寡糖组分;运用薄层色谱法（TLC）、荧光辅助糖...目的制备分离不同聚合度的甘露糖醛酸寡糖单体,测定其体外抗氧化活性。方法采用微波辅助降解法,制备甘露糖醛酸寡糖混合物,采用Bio Gel P-6凝胶渗透色谱法对寡糖混合物进行分离纯化,得到7个寡糖组分;运用薄层色谱法（TLC）、荧光辅助糖电泳法（FACE）、红外光谱法（IR）、质谱法（MS）对不同组分进行分析;比较不同寡糖组分对羟基自由基、超氧自由基、DPPH自由基的清除作用及对亚铁离子络合作用的差异。结果与结论采用微波辅助法能够实现对聚甘露糖醛酸的可控降解,通过对寡糖混合物进行分离纯化获得7个组分,分别为聚合度为1~7的饱和甘露糖醛酸寡糖。体外抗氧化研究表明,甘露糖醛酸寡糖具有清除DPPH、羟基自由基、超氧自由基及络合亚铁离子的能力,其活性与寡糖聚合度有关。清除DPPH、超氧自由基及络合亚铁离子的能力随着寡糖单体聚合度增大而降低;清除羟基自由基的能力随着聚合度增加而升高。展开更多
文摘Under certain conditions algal alginates bind pinacyanol chloride in the form of dimers – this is the conclusion drawn from a uv/vis and circular dichroism (CD) spectroscopic study of aqueous solutions of the dye in a 10-fold molar excess of the polysaccharide from different sources. With its easily detected features the dimer holds promise as a diagnostic tool for alginate conformational analysis. Binding of the strongly blue-shifted (maximum wavelength = 485 nm) dimer is probably mediated by the charged groups and involves guluronate units only. By using the peakFit program, the two overlapping excitonic absorption bands together with the optically inactive band resulted from the interaction of pinacyanol with a specific alginate concentration were separated. The standard Gibbs energy of the interaction was calculated as –27.02 kJ.mol–1. The dimers are sensitive against acid and divalent cations.
文摘It is reported that fermentative liquids with various concentrations of La and Nd affect the fer- mentation of alginic acid from the strain 342 of Azotobacter vinelandii.The results are as follows:When the concentration of La or Nd was up to 100 ppm,the cell growth is stimulated and the production of alginic acid is promoted.The La or Nd in concentration higher than 200 ppm or 150 ppm inhibits the fermentation, respectively.As the concentration range of La is 0～100 ppm or that of Nd is 0～150 ppm,the yield of fixed nitrogen increases,and the ratio of c_M to c_G(c_M/c_G)decreases with the raise of the concentration of La or Nd.When the concentration range of La is 100～400 ppm and that of Nd is 150～400 ppm,the conclusion is contrary to the above mentioned result.
文摘目的制备分离不同聚合度的甘露糖醛酸寡糖单体,测定其体外抗氧化活性。方法采用微波辅助降解法,制备甘露糖醛酸寡糖混合物,采用Bio Gel P-6凝胶渗透色谱法对寡糖混合物进行分离纯化,得到7个寡糖组分;运用薄层色谱法（TLC）、荧光辅助糖电泳法（FACE）、红外光谱法（IR）、质谱法（MS）对不同组分进行分析;比较不同寡糖组分对羟基自由基、超氧自由基、DPPH自由基的清除作用及对亚铁离子络合作用的差异。结果与结论采用微波辅助法能够实现对聚甘露糖醛酸的可控降解,通过对寡糖混合物进行分离纯化获得7个组分,分别为聚合度为1~7的饱和甘露糖醛酸寡糖。体外抗氧化研究表明,甘露糖醛酸寡糖具有清除DPPH、羟基自由基、超氧自由基及络合亚铁离子的能力,其活性与寡糖聚合度有关。清除DPPH、超氧自由基及络合亚铁离子的能力随着寡糖单体聚合度增大而降低;清除羟基自由基的能力随着聚合度增加而升高。
