Structure and function of polysaccharide produced by lactic acid bacteria aimed to add biological activity to yoghurt

保加利亚乳杆菌1073R-1胞外多糖经阴离子交换层析分离得到中性和酸性两种多糖。糖分析和核磁共振氢谱分析表明，中性和酸性多糖组成为含有半乳糖(Gal)和葡萄糖(GLC)的五糖重复单元，摩尔比为I3：I0，表观分子质量分别为I.2×10~(-6)DA和1.1×10~(-6)DA。酸性多糖中含有少量磷(0.1%)，能刺激小鼠脾细胞和Peyer‘s结的有丝分裂反应，但不能刺激胸腺细胞的分裂反应。最高刺激时多糖的最佳浓度为160µg/ml，刺激后24小时开始有丝分裂活性显著增加，刺激48小时后反应最强。氢氟酸降解引起的去磷酸化降低了淋巴细胞的有丝分裂活性。保加利亚乳杆菌OLL1073R-1产生的磷酸多糖是一种强烈的B细胞依赖的有丝分裂原，其中磷酸基团是有丝分裂的触发因素。APS能显著增强MPHI的吞噬活性，而NPS对MPHI的吞噬活性无明显影响。100µg/ml的APS处理MPHI 6h后，MPHI的细胞毒活性显著增强，且高于NPS处理的细胞毒活性。这些结果表明，保加利亚乳杆菌OLL1073R-1发酵食品有可能开发为具有生物功能的特殊食品。

The exocellular polysaccharide from Lactobacillus delbrueckii ssp.bulgaricus OLL 1073R-1 was fractionated into neutral and acidic polysaccharides by anion-exchange chromatography. Sugar analysis and ^1H NMR spectroscopy revealed that the neutral and acidic polysaccharides were composed of pentasaccharide repeating units containing galactose (Gal) and glucose (Glc) in the molar ratio of I.3 : I.0, and the apparent molecular weight were I.2 x 1O^6Da and 1.1 x 10^6Da, respectively. A slight amount (0.1%) of phosphorus was contained in the acidic polysaccharide.The acidic polysaccharide stimulated mitogenic responses of murine splenocytes and Peyer's patches but not of thymocytes. The optical concentration of the polysaccharide at the highest stimulation was 160 mug/ml. A significant increase of mitogenic activity was initiated at 24h, and the highest response was obtained after stimulation for 48h. Dephosphorylation by hydrofluoric acid degradation reduced the mitogenic activity in lymphocytes. The phosphopolysaccharide produced by Lactobacillus delbrueckii ssp.bulgaricus OLL1073R-1 is a potent B-cell-dependent mitogen in which the phosphate group acts as a trigger of the mitogenic induction.The effect of APS and NPS on macrophage (MPHI) functions was examined in vivo and in vitro in short-term studies. The phagocytic activity of peritoneal MPHI was significantly augmented by the intraperitoneal administration of APS,but not by NPS.The cytotoxic activity of thioglycolate-induced MPHI was significantly increased when it was treated with APS at a concentration of 100mug/ml for 6h, which activity was greater than that NPS treatment.These findings indicate the possibility that fermented food products made with L.bulgaricus OLL1073R-1 may be developed as special foods with biological functions.