b'Mathematically Unravelingthe Gut Ecosystem36This super-resolution image shows fruit fly gut crypts colonized by the native Lactobacillus (red) and Acetobacter (green) bacteria. Fly cell nuclei appear blue. Image courtesy Benjamin Obadia and Will LudingtonT he interactions among microbial species inThe effects of a particular microbial species the gastrointestinal system can have largedepend on the context of other species. Using effects on health, development, and longevity.the fruit fly Drosophila melanogaster, Ludington This ecosystem, called a microbiome, has hundredsand team developed a mapping system of all the to thousands of microbial species in the mammalianpossible interactions between the five species of gut. The diversity within the human gut challengesfly gut bacteria to see how they affect an insects our understanding of its effects on health. Willdevelopment, production of offspring, and lifespan. Ludington and team are using the simpler fruit flyThe team found that the interactions among gut as a model system to understand how complexmicrobial populations are as important to the flys microbial interactions affect our health. Their ultimatephysiology as the individual species.goal is to use this predictive power to engineer the microbiome.The microbiome consists of many interacting microbial species. Ludingtons team is deconstructing this complexity by calculating the geometric structure of the interactions. Their method measures interactions in multidimensional space, considering each species to have its own dimension. The mathematical structure can be thought of as foam being simplified into a single bubble by progressively merging adjacent bubbles.'