Abstract:
Every adult human carries a community of microbes numbering the trillions in their distal gut known as the Human Gut Microbiota. These microbes have evolved to effectively utilize a wide verity of chemically diverse carbohydrates which the host is unable to degrade. In return for nutrients from the human diet these microbes provide many health benefits to the host including, reducing the chance of developing bowel cancer and alleviating inflammatory bowel and metabolic disease symptoms. Bacteroides thetaiotaomicron, a Gram negative gut dwelling beneficial bacterium, is regarded as glycan utilization generalists, able to deconstruct and utilize many diverse glycan types. Bacteroides have developed sophisticated utilization systems involving surface glycan binding proteins and carbohydrate active enzymes to capture glycans and initiate degradation producing oligosaccharides which are imported into the periplasm by specialized TonB-Dependent Transporters. Once in the periplasm degradation is completed by further carbohydrate active enzymes. By using a combination of biochemical and microbiological techniques we have characterized a number of these systems to better understand the glycan utilization capabilities and preferences of this beneficial microbe in the human gut.