Wang Guohong, Zhai Zhengyuan, Ren Fazheng, Li Zaigui, Zhang Bing, Hao Yanling
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China; Key Laboratory of Functional Dairy, Co-constructed by Ministry of Education and Beijing Municipality, Beijing, China.
Food Res Int. 2020 Nov;137:109331. doi: 10.1016/j.foodres.2020.109331. Epub 2020 May 19.
Tolerance to bile stress is a crucial property for probiotics to survive in the gastrointestinal tract and exert their beneficial effects. In this work, transcriptomic analysis combined with two-dimensional electrophoresis revealed that the transcript levels of 129 genes and the abundance of 34 proteins were significantly changed in Lactobacillus salivarius Ren when exposed to 0.75 g/L ox-bile. Notably, carbohydrate metabolism shifted to the utilization of maltose and glycerol for energy production, suggesting that L. salivarius Ren expanded carbon sources profile for gut adaptation in response to bile. Moreover, the enzymes involved in cell surface charge modification and the cell envelope-located hemolysin-like protein were overproduced, which was supposed to hinder the penetration of bile. Then, the up-regulated ABC transporters could contribute to the extrusion of bile accumulated in the cytoplasm. Additionally, proteolytic system was activated to provide more amino acids for the synthesis and repair of proteins damaged by bile. Finally, γ-glutamylcysteine with antioxidant activity and oxidoreductases for redox homeostasis were increased to cope with the bile-induced oxidative stress. These findings provide new insights into the molecular mechanisms involved in bile stress response and adaptation in L. salivarius.
对胆汁应激的耐受性是益生菌在胃肠道中存活并发挥其有益作用的关键特性。在这项研究中，转录组分析结合二维电泳表明，唾液乳杆菌Ren在暴露于0.75 g/L牛胆汁时，129个基因的转录水平和34种蛋白质的丰度发生了显著变化。值得注意的是，碳水化合物代谢转向利用麦芽糖和甘油进行能量生产，这表明唾液乳杆菌Ren为适应肠道环境以应对胆汁而扩大了碳源谱。此外，参与细胞表面电荷修饰的酶和位于细胞包膜的溶血素样蛋白过量产生，这可能会阻碍胆汁的渗透。然后，上调的ABC转运蛋白可能有助于将积累在细胞质中的胆汁排出。此外，蛋白水解系统被激活，为胆汁损伤的蛋白质的合成和修复提供更多氨基酸。最后，具有抗氧化活性的γ-谷氨酰半胱氨酸和用于氧化还原稳态的氧化还原酶增加，以应对胆汁诱导的氧化应激。这些发现为唾液乳杆菌中胆汁应激反应和适应所涉及的分子机制提供了新的见解。
