岩藻多糖调节拟杆菌多糖利用策略改善肠道微生态平衡的研究

岩藻多糖是裙带菜的重要功能组分，其生物活性与对肠道微生态的改善密切相关。先前研究集中于肠道菌群，研究对象多为粪便，忽略了肠道菌群的空间异构性，也忽视了粘液层的作用。本项目综合运用微生物组学（测序及荧光原位杂交）、代谢组学及糖组学等技术从菌群结构与代谢两方面揭示岩藻多糖对肠道菌群空间结构的影响，结合对粘液层结构与O-糖链构成的研究，全面阐释岩藻多糖对肠道微生态的改善作用。为阐释其内在调控机制，本项目以肠道微生物对多糖的利用策略为切入点，以肠道拟杆菌为研究对象，解析拟杆菌利用岩藻多糖及粘蛋白的菌株特异性及分子机制，揭示岩藻多糖对拟杆菌群组成及粘蛋白分泌表达的影响，阐明岩藻多糖调节拟杆菌多糖利用策略抑制粘液层降解的分子通路，共同阐释岩藻多糖改善肠道菌群与粘液层微生态平衡的机制。该研究将为岩藻多糖在大健康产业中的应用提供理论支撑，为多糖的功能性评价提供新的理论依据，有助于个性化精准肠内营养的实施。

Fucoidan is a kind of important nutrients in Undaria pinnatifida, and its biological activities are closely associated with the improvement of the intestinal microecology. Previous studies revealed the effect of fucoidan on the gut microbiota via fecal sample, but the spatial organization of the gut microbiota and function of intestinal mucus were ignored. In this project, high throughput sequencing, fluorescence in situ hybridization and chromatography-mass spectrometry method are used to study the effect of fucoidan on the spatial organization of the gut microbiota and histology structure and O-glycan composition of intestinal mucus, indicating the improvement of fucoidan on the intestinal microecology. To elucidate the underlying mechanisms, intestinal Bacteroides species are collected, and their polysaccharide utilization strategy on fucoidan and mucus are fully analyzed. On this basis, the regulatory mechanisms of fucoidan on the balance of mucus between production and consumption are studied. It provides a theoretical basis for application of fucoidan in the health industry and evaluation of biological activities of polysaccharides, which would be helpful for the promotion of personalized nutrition.