Intestinal helminths reverse gut dysbiosis induced by urbanization: case study in a small rodent

我分析了从城市公园和国家森林采集的3种啮齿类动物（即斑尾鼠、阿根特鼠和红背鼠）184只，沿消化道四个区域（小肠、盲肠、结肠和直肠）的肠道微生物群。我发现微生物群落在两种类型的栖息地之间存在差异，城市的rufocanus可能正在经历生态失调（即不健康的肠道微生物群）。特别是，城市的rufocanus在下消化道中含有更高丰度的潜在致病性幽门螺杆菌。通过稳定同位素分析其饮食习惯，笔者发现，与自然同种相比，城市拟南棘的饮食生态位有所扩大。此外，这两个物种在城市栖息地内都经历了与生活史相适应的饮食转变，其中斑蝽消耗更多的动物蛋白，而褐毛蝽消耗更多的C3植物。这种饮食的改变部分解释了观察到的肠道微生物群的变化。最后，我发现蠕虫可能通过促进丁酸梭菌等益生菌物种来帮助保护城市动物免受生态失调。

I analyzed the gut microbiota in four regions (i.e. small intestine, cecum, colon, and rectum) along the digestive tract of 184 rodents comprised of three species (i.e. Apodemus speciosus, A. argenteus, and Myodes rufocanus) collected from urban parks and the national forest. I found that the microbial community differed between the two types of habitat and that urban M. rufocanus may be experiencing dysbiosis (i.e. unhealthy gut microbiota). In particular, urban M. rufocanus is harboring higher abundances of potentially pathogenic Helicobacter in the lower gastro intestinal tract. By analyzing their dietary habits using stable isotope analysis, I found that urban A. speciosus exhibited an expanded dietary niche as compared to their natural conspecifics. Furthermore, both species have undergone a dietary shift within the urban habitat in accordance with their life history with A. speciosus consuming more animal protein and M. rufocanus more C3 plants. This dietary shift partially explains the observed changes in the gut microbiota. Lastly, I found that helminths may help protect urban animals from dysbiosis through the promotion of probiotic bacterial species such as Butyricicoccus.