【作者】 李泉岑； 许欢怡； 刘斌； 郑明锋； 曾峰；

【Author】 LEE Quancen;XU Huanyi;LIU Bin;ZHENG Mingfeng;ZENG Feng;College of Food Science, Fujian Agriculture and Forestry University;Engineering Research Center of Fujian Subtropical Fruit and Vegetable Processing;National Engineering Research Center of JUNCAO Technology;

【机构】 福建农林大学食品科学学院； 福建省亚热带果蔬加工工程技术研究中心； 国家菌草工程技术研究中心；

【摘要】 银耳是珍贵的食用和药用真菌,营养价值很高,其中富含的银耳多糖(Tremella fuciformis polysaccharides, TFP)具有多种生物活性。本研究首先通过不同方法制备银耳低分子量多糖(Lowmolecularweightpolysaccharidesof Tremella fuciformis, TFLPs),采用秀丽隐杆线虫模型筛选出体内抗氧化活性最佳的TFLPs制备方法,在m RNA转录水平及代谢物水平上分析其抗氧化的作用机制,然后通过小鼠模型研究其对机体和肠道抗氧化、免疫调节活性和肠道菌群的影响及作用机制。结果发现,TFPs提高抗氧化酶活力从而增强秀丽隐杆线虫的热应激和急性氧化应激抗性,筛选出抗氧化活性最佳的TFLP制备方法为压热酸解法。秀丽隐杆线虫抗氧化活性和应激抗性的提高与fat-5、fat-6、fat-7、glp-1、hsf-1和hsp-1m RNA转录水平的上调有关,同时糖基磷脂酰肌醇(GPI)-生物合成、自噬、糖蛋白代谢和嘌呤代谢途径是秀丽隐杆线虫抗氧化活性和应激抗性的关键代谢途径。在环磷酰胺诱导的免疫抑制小鼠模型中,TFP和TFLP显著改善免疫抑制小鼠的血常规水平,提升血清细胞因子(IL-2、IL-6、IFN-γ)和免疫球蛋白(IgM和IgG)水平,提高抗氧化酶活力,增强脾脏抗氧化酶活力和淋巴细胞增殖水平发挥机体免疫调节活性;同时TFP和TFLP能够调节免疫抑制小鼠的肠道免疫,降低小肠MPO水平,提高小肠细胞因子水平和抗氧化酶活力,改善小肠绒毛长度和隐窝深度,增加杯状细胞数量;TFLP干预的小鼠肠道菌群多样性增加,F/B值显著下降,其中作为特征菌属的阿克曼菌属、拟杆菌属和拟普雷沃菌属的丰度显著上调。研究结果表明,TFP和TFLP具有显著的体内抗氧化和免疫调节活性,本研究可为银耳等食药用菌的精深加工及营养功能性食品的研发提供理论依据。更多还原

【Abstract】 Tremella fuciformis(TF) is a valuable edible and medicinal fungus, its nutritional value of T. fuciformis is excellent, and Tremella fuciformis polysaccharides(TFP) have various biological activities. In this study, low molecular weight polysaccharides of Tremella fuciformis(TFLPs) were obtained by degrading TFP through different methods and the best TFLP preparation method with in vivo antioxidant activity was screened through Caenorhabditis elegans(C. elegans).In addition, the mechanism of its regulation of antioxidant activity was explored at the level of m RNA transcription and changes in metabolites. The effects of TFP and TFLP on organism and intestinal immunity were investigated through mice model and the mechanism of their immune regulatory activity was explored through gut microbiota sequencing. It was found that TFPs could enhance the heat stress and acute oxidative stress resistances of C. elegans by increasing the activity of antioxidant enzymes. Among them, the TFLP preparation method with the best antioxidant activity was selected as pressure-heating assisted acid hydrolysis. The improvement of antioxidant activity and stress resistance of C. elegans was closely related to the increase of the m RNA transcription of fat-5, fat-6, fat-7, glp-1, hsf-1 and hsp-1.Glycosylphosphatidylinositol(GPI)-either biosynthesis, autophagy, glycophorin metabolism, and purine metabolism pathways were key metabolic pathways of antioxidant activity and stress resistance in C. elegans supplemented with TFLP.In addition, its immunostimulatory activity was explored by constructing cyclophosphamide-induced immunosuppressive mice, and it was found that TFP and TFLP could significantly exerted the immune regulatory activity of organism through improving the blood routine levels, promoting serum cytokines(IL-2, IL-6, IFN-γ), immunoglobulin(IgM and IgG) and antioxidant enzyme activities in mice, and enhancing spleen antioxidant enzyme activity and lymphocyte proliferation level.At the same time, it was found that TFP and TFLP could regulate the intestinal immunity of mice by reducing intestinal MPO levels, increasing intestinal cytokine levels and antioxidant enzyme activities, improving intestinal villus length and crypt depth, as well as the number of goblet cells. Meanwhile, it was found that the diversity of gut microbiota in mice treated with TFLP was increased, and the F/B value was significantly decreased. Among them, Akkermansia, Bacteroides,and Alloprevotella as the characteristic genera, their abundance was significantly upregulated. In this study, TFP and TFLP had significant antioxidant and immunomodulatory activities, providing a theoretical basis for the further processing of edible and medicinal fungi such as TF and the development of related functional products.更多还原