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Full-Text Articles in Life Sciences
The Catalytic Urease Subunit Urec Is Critical For Bifidobacterium Longum Urea Utilization, Yang Lyu
The Catalytic Urease Subunit Urec Is Critical For Bifidobacterium Longum Urea Utilization, Yang Lyu
Doctoral Dissertations
In the first study, we investigated the utilization of a human milk nitrogen source, urea, by Bifidobacterium. Urea accounts for ~15% in human milk, which is an abundant non-protein nitrogen (NPN). Some bifidobacteria are found to harbor urease gene clusters that potentially enable their hydrolysis of the human milk urea. However, the underlying mechanisms are still unclear. To incisively link the urease gene cluster with bifidobacterial urea utilization, chemical mutagenesis (i.e. ethyl methanesulfonate) was performed on the urease-positive Bifidobacterium longum subsp. suis UMA399. Mutants were selected on differential media and genetic lesions were identified using whole genome sequencing. …
Dietary Oligosaccharides Are Differentially Metabolized By Commensal Microbiota Within In Vitro Model Systems, Ezgi Özcan
Doctoral Dissertations
Our diet contains indigestible carbohydrates that are available for microbial metabolism within the gastrointestinal tract. These carbohydrate sources are oligosaccharides found in plants and human milk. Oligosaccharide utilization phenotypes are often consistent with the ecological niche that microbes occupy (e.g. adult gut, infant gut, plants). This study represents an in-depth metabolic analysis for utilization of human milk oligosaccharides (HMOs) including lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT), and cranberry oligosaccharides (i.e. xyloglucans) within in vitro modeled systems. These model systems include microplate systems for pure cultures as well as an adapted bioreactor system to mimic microbial interactions within the gut. Infant-colonizing Bifidobacterium …