Samuels Amanda N, Roggiani Manuela, Smith Kathryn A, Zhu Jun, Goulian Mark, Kohli Rahul M
Department of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA19104, USA.
Graduate Group on Cell and Molecular Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104, USA.
Microorganisms. 2020 May 2;8(5):664. doi: 10.3390/microorganisms8050664.
Colicins are specific and potent toxins produced by that result in the rapid elimination of sensitive cells. Colicin production is commonly found throughout microbial populations, suggesting its potential importance for bacterial survival in complex microbial environments. Nonetheless, as colicin biology has been predominately studied using synthetic models, it remains unclear how colicin production contributes to survival and fitness of a colicin-producing commensal strain in a natural environment. To address this gap, we took advantage of MP1, an strain that harbors a colicinogenic plasmid and is a natural colonizer of the murine gut. Using this model, we validated that MP1 is competent for colicin production and then directly interrogated the importance of colicin production and immunity for MP1 survival in the murine gut. We showed that colicin production is dispensable for sustained colonization in the unperturbed gut. A strain lacking colicin production or immunity shows minimal fitness defects and can resist displacement by colicin producers. This report extends our understanding of the role that colicin production may play for during gut colonization and suggests that colicin production is not essential for a commensal to persist in its physiologic niche in the absence of exogenous challenges.
大肠杆菌素是由[具体微生物]产生的特异性强效毒素，可导致敏感细胞迅速清除。大肠杆菌素的产生在整个微生物群体中普遍存在，这表明其在复杂微生物环境中对细菌生存具有潜在重要性。尽管如此，由于大肠杆菌素生物学主要是使用合成模型进行研究的，目前尚不清楚大肠杆菌素的产生如何有助于产生大肠杆菌素的共生菌株在自然环境中的生存和适应性。为了填补这一空白，我们利用了MP1，这是一种携带产大肠杆菌素质粒的[具体微生物]菌株，是小鼠肠道的天然定植菌。利用这个模型，我们验证了MP1能够产生大肠杆菌素，然后直接探究了大肠杆菌素的产生和免疫对MP1在小鼠肠道中生存的重要性。我们发现，在未受干扰的肠道中，持续定植并不依赖于大肠杆菌素的产生。缺乏大肠杆菌素产生或免疫的菌株显示出最小的适应性缺陷，并且能够抵抗大肠杆菌素产生菌的取代。本报告扩展了我们对大肠杆菌素产生在肠道定植过程中可能发挥的作用的理解，并表明在没有外源挑战的情况下，大肠杆菌素的产生对于共生菌在其生理生态位中持续存在并非必不可少。
