Collaborative Research: The role of gut microbiota in supplying amino acids to their mammalian hosts

Microbes living in digestive tracks are now recognized as important contributors to the health and fitness of animals. Within a single host, thousands of different microbial species form symbiotic communities influenced by many factors, including host diet. These communities often metabolize compounds that their hosts cannot, and likely supply essential compounds needed for growth and reproduction, particularly for organisms that experience protein limitation. To date, the role the gut microbiome plays in the protein metabolism of its hosts has not been systematically explored. This project will combine studies of the building blocks of proteins (amino acids), stable isotope techniques, and next generation DNA sequencing to answer two questions. First, how does gut microbiome contribute to the building and maintenance of tissues by its hosts? And second, which microbial species are most important in the gut? In addition, a series of controlled feeding experiments where the diet will be systematically varied will also determine the role that the gut microboime plays in the relationship between hosts and the resources they consume. This work will provide many opportunities for training STEM students through hands-on experiences. These experiences are important for young scientists as they gain confidence and nurture identities as independent researchers. University of New Mexico and University of California at Riverside are both minority-majority universities and certified Hispanic Serving Institutions. The research group will also host two workshops to discuss how animal and microbial ecologists can work together to study interactions between gut microbes and their host organisms.<br/><br/>Gut microbiota are integral components contributing to the health and fitness of animals. Animal ecologists and eco-physiologists are discovering the many positive and negative roles microbes play in contributing to their hosts. Within a single host, thousands of different microbial species form symbiotic communities influenced by many factors, including host diet. These communities often metabolize compounds that their host species cannot, and likely supply essential compounds needed for homeostasis and reproduction, particularly for organisms that experience seasonal diet stress or protein limitation. This project will combine studies of amino acids using stable isotope techniques coupled with next generation genetic sequencing to (1) identify and potentially quantify, the degree to which the gut microbiome contributes to protein budgets and the building and maintenance of tissues by its hosts, and (2) characterize which microbial taxa are most closely associated with digestive metabolisms in the gut, in which amino acids are used subsequently by the host to synthesize tissues. These topics will be addressed through a series of controlled feeding experiments on deer mice where the proportion and isotopic compositions of dietary macromolecules and individual compounds will be systematically varied. The study will produce a more thorough understanding of the role that the gut microboime plays in influencing natural isotope tracers, a tool for quantifying diet composition and trophic level of wild animals. The research group will also host two workshops to discuss how animal and microbial ecologists can combine genetic and isotopic data to study biochemical interactions between gut microbes and their host organisms.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.