My current research projects at the University of Michigan focus on metabolism of complex carbohydrates (glycans or polysaccharides) and other nutrients, such as dietary protein, by human gut bacteria. Many different lineages of human gut bacteria have evolved mechanisms to degrade dietary fiber polysaccharides and some can access mucus glycoproteins for nutrients. Understanding the mechanisms by which gut bacteria metabolize different glycans represents an important step in interpreting the behavior and function of organisms and genes that are present in the human microbiome. Ongoing studies in my lab include: 1) Exploring the mechanisms through which “commensal” microbiota and their resident bacteriophages contribute to inflammatory bowel disease in genetically susceptible hosts by degrading intestinal mucus glycans and characterization of the enzymes involved; 2) Investigating how symbiotic gut bacteria like Bacteroides and members of other taxa metabolize the widely varied polysaccharide structures found in dietary fiber polysaccharides and mucin glycoproteins; 3) Exploring the enzymatic, sensory and transport mechanisms through which carbohydrate degradation occurs in Bacteroides and other gut microbes along with genome evolution events that mediate lateral gene transfer of these traits; 4) exploring the roles of polysaccharide capsules in B. thetaiotaomicron interactions with host immunity and bacteriophage.

Recognition and metabolism of complex carbohydrates and other dietary nutrients by human distal gut bacteria

Role of bacterial degradation of secreted host mucus and extracellular matrix glycoproteins in inflammatory bowel disease, enteric infection and colorectal cancer

Genomic evolution and lateral gene transfer in human gut bacteria and their environmental relatives

Assembly, ecology and function of complex microbial communities in animal guts

Development of diet- and microbiome-based therapeutics to treat human disease or promote intestinal health

Mechanisms of bacteria-bacteriophage interaction and persistence in the human gut