低聚半乳糖定向促进食品源乳酸菌在断奶仔鼠中拮抗蜡样芽孢杆菌的机制研究

膳食中微生物可获得性碳水化合物（MACs）的缺失易导致肠道菌群多样性降低，并影响机体健康。功能性低聚糖是一类理想的MACs，不被消化且能选择性促进肠道固有益生菌的增殖，进而抑制病原菌的繁殖，但对其精准促进外源乳酸菌在肠道定植并拮抗病原菌的机制了解甚微。申请人拟在前期发现植物乳杆菌ZDY2013与产肠毒素蜡样芽孢杆菌互作具有竞争优势，其生物活性可被低聚半乳糖增强的基础上，以肠道微生物尚不稳定的断奶仔鼠为研究模型，通过菌株体内互作实验，定位、定量分析菌株定植和粘附位点相关蛋白的表达，关联分析仔鼠肠道代谢产物、特征细胞因子、关键菌属丰度和相关功能基因差异表达，阐明低聚半乳糖定向促进肠道外源植物乳杆菌在仔鼠肠道的定植建立及拮抗蜡样芽孢杆菌的相关机制。研究结果将为科学认知膳食靶向改善乳酸菌的功能提供理论依据。

Diet deprived of microbiota-accessible carbohydrates (MACs) leads to a reduction in gut microbial diversity and alters its physiological function. Functional oligosaccharide is one of the desired MACs due to its indigestibility and selective promotion of autochthonous probiotics proliferation, which can subsequently inhibit pathogens. However, the oligosaccharides’ mechanism in promoting the colonization of allochthonous lactic acid bacteria and antagonizing pathogens remains unknown. Based on the previous study, Lactiplantibacillus plantarum ZDY2013 had a competitive advantage when interacting with enterotoxigenic Bacillus cereus, and its bioactivities could be enhanced by galactooligosaccharide. This study will use weaned rats with an unstable gut microbiome as the model to execute strain interaction assay. The strain colonization and protein expression of adhesion will be analyzed quantificationally, while gut metabolites, characteristic cytokines, the abundance of key bacteria, and the differentially expressed functional genes will be analyzed together to elucidate the mechanism of galactooligosaccharides in promoting the colonization of L. plantarum and antagonization of B. cereus. These results may provide a theoretical foundation for the scientific cognition of precision-based modulation of lactic acid bacteria functionality that is ameliorated by the diet.