Institute of Bioengineering and Global Health Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland.
Proc Natl Acad Sci U S A. 2023 Jun 20;120(25):e2217577120. doi: 10.1073/pnas.2217577120. Epub 2023 Jun 12.
Bacterial gut commensals experience a biologically and physically complex mucosal environment. While many chemical factors mediate the composition and structure of these microbial communities, less is known about the role of mechanics. Here, we demonstrate that fluid flow impacts the spatial organization and composition of gut biofilm communities by shaping how different species interact metabolically. We first demonstrate that a model community composed of () and (), two representative human commensals, can form robust biofilms in flow. We identified dextran as a polysaccharide readily metabolized by but not , but whose fermentation generates a public good enabling growth. By combining simulations with experiments, we demonstrate that in flow, biofilms share dextran metabolic by-products, promoting biofilm formation. By transporting this public good, flow structures the spatial organization of the community, positioning the population downstream from . We show that sufficiently strong flows abolish biofilm formation by limiting the effective public good concentration at the surface. Physical factors such as flow may therefore contribute to the composition of intestinal microbial communities, potentially impacting host health.
肠道共生细菌处于一个具有生物学和物理复杂性的黏膜环境中。虽然许多化学因素调节这些微生物群落的组成和结构，但力学的作用知之甚少。在这里，我们证明了流动会通过影响不同物种之间的代谢相互作用来塑造肠道生物膜群落的空间组织和组成。我们首先证明了由（）和（）组成的模型群落，这两种共生菌都是人类的代表菌，可以在流动中形成坚固的生物膜。我们发现葡聚糖是一种很容易被代谢的多糖，但不能被利用，但其发酵产生的公共产物可促进生长。通过结合模拟实验，我们证明在流动中，生物膜共享葡聚糖代谢副产物，促进生物膜形成。通过运输这种公共产物，流动结构了群落的空间组织，将种群定位在下游。我们表明，足够强的流动通过限制表面处有效公共产物浓度来消除生物膜的形成。因此，物理因素（如流动）可能有助于肠道微生物群落的组成，从而可能影响宿主健康。
