合成共轭亚油酸益生菌的筛选及其免疫调节功能分析word格式论文.docx

的合成能力。此外，葡萄糖和半乳糖的糖代谢产物乙酸、丙酸和乳酸通过增加菌 株 F0221 细胞膜的渗透性，增强了底物 LA 进入细胞的能力，提高了细胞内 LA 与 镶嵌于细胞膜上的 LA 异构酶的接触频率，从而增强菌株单位细胞合成 c9，t11 CLA 的效率。以小鼠为模型，对菌株 F0221 的体内繁殖、c9，t11 CLA 合成及免疫调节能力 进行了研究。摄食菌株 F0221 后，小鼠回肠和结肠内乳杆菌数量显著（P0.05） 增加，这提示该菌株具有短期、潜在的在小鼠回肠和结肠上皮细胞定植的能力。 同时，小鼠肠道内容物中 c9，t11 CLA 含量显著（P0.05）增加，说明该菌株在小 鼠体内同样具有合成 c9，t11 CLA 的能力。肠道内合成的 c9，t11 CLA 转移到了血 清、肝脏和脂肪组织中，降低其中花生四烯酸水平、抑制了具有下调机体免疫调 节能力的前列腺素（PGE2）的合成能力。PGE2 水平的降低提高了小鼠脾脏 T 淋巴 细胞和 B 淋巴细胞的增殖能力、腹腔巨噬细胞的增殖能力以及血清中细胞因子 IL-2 和 TNF-α 的水平，进而提高了机体免疫调节能力。研究了吐温 80 和 GOS 对菌株 F0221 在小鼠体内合成 c9，t11 CLA 能力和调节机体免疫能力的影响，发现吐温 80 和 GOS 可显著（P0.05）提高菌株体内合成 c9，t11 CLA 的能力，进而增强了 其对机体免疫能力的调节作用。这提示吐温 80 和 GOS 可以作为菌株 F0221 体内 发挥免疫调节功能的促进剂。关键词：共轭亚油酸；益生菌；免疫调节功能AbstractCis-9, trans-11 conjugated linoleic acid (c9, t11 CLA) is octadecadienoic acid. C9, t11 CLA has many biological effects, including immunomodulatory function. C9, t11 CLA producing probiotic can converet dietary linoleic aicd (LA) to c9, t11 CLA in the intestinal tract, and then enhance immunomodulatory function.In this study, the c9, t11 CLA producing probiotic was screened, and subsequently the in vitro influencing factor of c9, t11 CLA production and in vivo immunomodulatory function of the selected strains were investigated.One hundred ninety-three strains were selected from traditional Chinese fermented foods and feces. According to the ultraviolet colorimetry method, 12 strains were screened for their ability to produce CLA. In particular, strains F0721, F0221, IN5.22, G14, M6 and Q9 were found with c9, t11 CLA production ability by the gas chromatography (GC) detection. The six strains mentioned above were investigated for the ability to survive in vitro simulating gastric juice, to grow in the presence of bile salt and to adhere to HT-29 cell. The strain F0221 was finally selected as c9, t11CLA producing probiotic and was identified as Lactobacillus acidophilus F0221 by 16S rDNA gene sequence analysis. Incubation of L.acidophilus F0221 at pH 6.5 followed byanaerobic incubation at