消化道环境胁迫对青春双歧杆菌KLDS2.0003粘附能力影响

摘要

To determine the impact of the digestive tract environment on the adhesion ability,surface property of bacteria and bacterial cell membrane fatty acid composition of Bifidobacterium adolescentis KLDS2.0003.Method:in vitro gastrointestinal model was established to simulate in vivo gastrointestinal environment and Bifidobacterium adolescentjs KLDS2.0003 were treated under in vitro gastrointestinal environment Caco-2 cells were used as adhesion models,bacterial survival rate and adhesion ability before and after treatment was measured in vitro by direct microscopic examination and colony counting method,at the same time the bacterial cell morphology,automatic aggregation ability and surface hydrophobicity were analyzed.GS-MS was used to determinate changes of membrane fatty acid composition of bacteria before and after treatment.Results showed that the adhesion ability decreased,bacterial cell morphology changed,bacterial surface hydrophobicity and the automatic aggregation ability of bacteria declined,the ratio between bacteria membrane unsaturated fatty acids and saturated fatty acid was increased,and a new long-chain unsaturated fatty acid C18:2n6c generated after Bifidobacterium adolescentis KLDS2.0003 was stressed by in vitro gastrointestinal environment.Conclusion:the adhesion ability of Bifidobacterium adolescentis KLDS2.0003,automatic bacterial aggregation ability and surface hydrophobicity decreased after gastrointestinal environment stress and there was a certain correlation among the three changes.In addition,it was speculated that Bifidobacterium adolescentis KLDS2.0003 adapted to gastrointestinal environment by adjusting the bacterial cell membrane fatty acid composition.%确定消化道环境胁迫对青春双歧杆菌KLDS2.0003粘附能力、菌体表面性质及菌体细胞膜脂肪酸组成影响.采用体外方法模拟消化道环境,以Caco-2细胞作为粘附模型,青春双歧杆菌KLDS2.0003相继经过模拟唾液、模拟胃液以及模拟肠液处理后,测定经历模拟消化道环境前后存活率、粘附能力、自动聚集能力和表面疏水性,同时采用扫描电镜和透射电镜观察菌体形态以及采用GS-MS法测定菌体处理前后细胞膜脂肪酸组成变化.结果表明,青春双歧杆菌KLDS2.0003经模拟消化道环境胁迫后,粘附能力下降,菌体表面疏水性、自动聚集能力菌下降、菌体细胞形态发生改变,膜不饱和脂肪酸与饱和脂肪酸比例增加,而且有一种新长链不饱和脂肪酸C18:2n6c产生.结果显示,消化道环境胁迫会降低青春双歧杆菌KLDS2.0003粘附能力,同时菌体自动聚集能力和表面疏水性均降低,三者之间呈现一定相关性,此外,在消化道环境胁迫条件下,膜脂肪酸组成发生改变,诱导产生一种新长链不饱和脂肪酸C18:2n6,c推测该菌通过调节膜脂肪酸组成变化以抵抗消化道环境中不利因素.