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

采用阴离子交换层析法对德氏乳杆菌保加利亚亚种OLL 1073 R-1胞外多糖进行了分离纯化。糖分析和核磁共振氢谱分析表明，中性和酸性多糖均由五糖重复单元组成，其中半乳糖和葡萄糖的摩尔比为1.3：1.0，表观分子量分别为1.2 × 10^6Da和1.1 × 10^6Da。酸性多糖中含有0.1%的磷，能刺激小鼠脾细胞和派伊尔集合淋巴结的有丝分裂反应，但对胸腺细胞无刺激作用。多糖在最高刺激下的光学浓度为160 μ g/ml。24 h时细胞增殖活性开始明显增强，48 h时细胞增殖活性最高。通过氢氟酸降解的去磷酸化降低了淋巴细胞的促有丝分裂活性。德氏乳杆菌保加利亚亚种OLL 1073 R-1产生的磷酸多糖是一种强有力的B细胞依赖性有丝分裂原，其中磷酸基团作为有丝分裂诱导的触发剂。腹腔注射APS可显著增强MPHI的吞噬活性，而腹腔注射黄芪多糖则无此作用。这些发现表明，用保加利亚乳杆菌OLL 1073 R-1073 R-1可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.