Fecal microbiota reveal adaptation of herbivores to the extreme environment of the Qinghai–Tibet Plateau

Background:Gut microbiota is pivotal in regulating hosts'biological processes and maintaining homeostasis,but knowledge about its role in wild herbivores in extreme environments remains limited.Methods:Gut bacteria and fungi were sequenced in ruminant(Chiru and Yak)and nonruminant(Kiang)herbivores on the Qinghai–Tibet Plateau,and their community structure,co-occurrence networks,functions,and assembly mechanisms were investigated using multivariate ecological and statistical methods.Results:Kiang had lower gut microbial diversity than Chiru and Yak.Bacterial host-specific exclusivity was greater than that of fungi.In addition to the evidence of glycan biosynthesis and carbohydrate metabolism,Chiru had a high Firmicutes/Bacteroidetes ratio and low animal pathogen abundance,suggesting better adaptation to the plateau's harsh environment.Additionally,members of gut microbiota tended to co-occur rather than co-exclude in all herbivores.Different network complexity and stability patterns were observed between bacterial and fungal communities.Furthermore,gut bacterial assembly was primarily controlled by stochastic dispersal limitation and drift,whereas fungal assembly was primarily controlled by deterministic homogeneous selection except in Chiru.Conclusions:On the Qinghai–Tibet Plateau,Chiru and Yak exhibit more diverse gut microbiota and more diverse metabolic functions than Kiang,and gut bacteria are more divergent than gut fungi in these herbivores.

中药白及在口腔疾病中的研究与应用

白及作为我国传统的中药材,分布广泛、价廉易得。随着中医药的蓬勃发展,白及在临床医学上的应用也更为深入,包括抗菌、抗肿瘤、治疗消化道溃疡、胃黏膜病变和体内外出血等。本文对白及的药理特性、化学成分做一总结,同时分析各成分在治疗中的机制和通路,着重归纳整理了白及在口腔疾病领域的应用,包括口腔黏膜类疾病、龋病、髓腔内屏障材料和牙周组织工程支架材料等,证明了白及无论是单味用药还是配伍用药,都能依靠其自身特性发挥重要功效,为进一步推广白及在口腔疾病治疗中的研究应用提供参考。