Ecosystem in a box: Dissecting the dynamics of a defined microbial community in vitro

ended

The dynamics of microbial communities may be driven by the interactions between community members, controlled by the environment, shaped by immigration or random events, influenced by evolutionary processes or result from an interplay of all these factors. This project aims to improve our understanding of how community structure and the environment impact community dynamics. Towards this aim, a defined in vitro community of human gut bacteria will be assembled, since their genomes are available and their metabolism is comparatively well resolved. In the first step, we will quantify the intrinsic variability of community dynamics and look for alternative stable states. Next, we will systematically vary community structure as well as nutrient supply and monitor their effects on the dynamics. Finally, we will measure model parameters, evaluate to what extent different community models predict observed community dynamics and validate the models by identifying and experimentally validating keystone species. Studies of microbial community dynamics are hampered by the cost of obtaining densely sampled time series in replicates and by the difficulty of community manipulation. We will address these challenges by setting up an in vitro system for parallel and automated cultivation in well-controlled conditions and by working with defined communities, where every community member is known. The proposed project will discern how external factors and community structure drive community dynamics and encode this knowledge in mathematical models. Moreover, the project has the potential to transform our view on alternative microbial communities and their interpretation. In addition, the project will extend our knowledge of human gut microorganisms and their interactions. These insights will ease the design of defined gut communities optimized for therapeutic purposes.