肠道微生物群（gut microbiome）是众多有益细菌的集合，是我们整体健康的关键。最近的研究已经将肠道微生物群与一些有益的特性联系起来，例如帮助我们免疫系统的发育和防止病原体感染。

Two-faced bacteria

https://www.sciencedaily.com/releases/2020/03/200305135045.htm

Journal Reference:

1. Jingyun Yang, Ravi Chawla, Kathy Y. Rhee, Rachit Gupta, Michael D. Manson, Arul Jayaraman, Pushkar P. Lele. Biphasic chemotaxis of Escherichia coli to the microbiota metabolite indole. Proceedings of the National Academy of Sciences, 2020; 201916974 DOI: 10.1073/pnas.1916974117