Presenter(s): Dylan Martins − Biology
Faculty Mentor(s): Raghuveer Parthasarathy
Poster 44
Research Area: Natural/Physical Science
The intestines of humans and other animals are home to tens of trillions of microbes. These microbial communities play important roles in health and disease, and are composed of dozens to hundreds of interacting species. While the factors that determine a particular species’ presence in the gut are largely unknown, both physical and biochemical interactions between species are likely important. Learning about these factors poses challenges due to the difficulty of performing controlled experiments with existing tools.
This project addresses these challenges by constructing five-species microbial communities in zebrafish, a model vertebrate animal to determine whether these model groupings are stable, and what inter-species interactions are evident. We use zebrafish as a model organism because they can live in a bacterially controlled environment and because their larval transparency allows for live microscopy. Experimentally, we introduce commensal intestinal microbes to larval zebrafish, initially raised germ-free to allow introduction of controlled combinations of bacterial species. Using a combination of conventional dissection and plating assays and three-dimensional live imaging, we have been able to demonstrate the existence of stable multi-species communities, and we can test whether outcomes from two-species competitions contain enough information to allow prediction of multi-species abundances and interactions, of key importance to creating predictive models of the human gut. Further, we find that individual species are differentially sensitive to the presence of other species, and that the community stability is sensitive to the presence of certain species. Correlations can also be identified between species and their spatial structure within the fish gut.
The microbiome is important to health and disease, but it is a complex system which is difficult to understand. By constructing a model system in a vertebrate gut that has an interesting and tractable number of species, we gain insights and reveal principles that might apply to the human microbiome.