Evolving Better Biofilms: The Dynamics of Community-Level Natural Selection in Bacteria

这个项目使用细菌和计算模型系统来研究多物种群落的进化。生物膜是细菌的集合体，它们附着在有生命的和无生命的表面上，以及彼此之间。它们往往由多种物种组成，会导致人类疾病，污染医疗和食品生产设备，腐蚀管道，净化受污染的水，并保护材料不被降解。在这个项目中，将在体外和硅胶中选择物种群落，以生产对寄生虫、抗生素和/或腐蚀性化学品更强大和更耐受的生物膜。这些实验将阐明物种组成和多样性对成功群落进化的影响。自然选择不仅有利于适合的生物体，而且可以在更高的水平上发挥作用，有利于整个种群而不是其他种群，这一过程被称为群体选择。在多物种细菌感染中，形成稳定的、可传播的感染的物种组合将成功地增殖到新的宿主，因此将被作为一个完整的集合进行进一步进化。在奶酪生产和废水净化中，乳制品生产商和环境工程师人为地从混合细菌群落中挑选出执行这些任务最好的细菌。是什么让混合社区比同类社区更好地解决了一些生态问题？社区级别的进化是否遵循与个体级别的进化相同的原则？尽管混合微生物群落是许多健康和环境问题的基础，但对它们的进化几乎一无所知。由于生物膜在自然界中既可以作为单一培养物，也可以作为混合培养物，它们为探索社区级选择的基本原理提供了一个理想的试验台。

This project addresses the evolution of multi-species communities using both bacterial and computational model systems. Biofilms are assemblages of bacteria that adhere to surfaces, both living and nonliving, and to each other. They are often composed of multiple species and cause human diseases, contaminate medical and food production equipment, corrode pipes, purify polluted waters, and protect materials from degradation. In this project, communities of species will be selected both in vitro and in silico to produce biofilms that are stronger and more resistant to parasites, antibiotics and/or caustic chemicals. These experiments will illuminate the effects of species composition and diversity on the evolution of a successful community.Natural selection not only favors fit organisms but also can act at a higher level, favoring entire populations over others, a process known as group selection. In multi-species bacterial infections, combinations of species that form stable, transmissible infections will successfully proliferate to new hosts, and will thereby be favored as an entire assemblage for further evolution. In cheese production and wastewater decontamination, dairy producers and environmental engineers artificially select among mixed communities of bacteria for those that perform these tasks best. What allows mixed communities to solve some ecological problems better that homogeneous communities? Does community-level evolution follow the same principles as individual-level evolution? Although mixed microbial communities underlie many health and environmental concerns, virtually nothing is known about their evolution. Because biofilms thrive in nature as both monocultures and mixed cultures, they offer an ideal test bed for exploring the fundamentals of community-level selection.