Cuskin, FionaLowe, Elisabeth C.Temple, Max J.Zhu, YanpingCameron, ElizabethPudlo, Nicholas A.Porter, Nathan T.Urs, KarthikThompson, Andrew J.Cartmell, AlanRogowski, ArturHamilton, Brian S.Chen, RuiTolbert, Thomas J.2017-04-272017-04-272015-01-08Cuskin, F., Lowe, E. C., Temple, M. J., Zhu, Y., Cameron, E., Pudlo, N. A., … Gilbert, H. J. (2015). Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism. Nature, 517(7533), 165–169. http://doi.org/10.1038/nature13995https://hdl.handle.net/1808/23829Yeasts, which have been a component of the human diet for at least 7000 years, possess an elaborate cell wall α-mannan. The influence of yeast mannan on the ecology of the human microbiota is unknown. Here we show that yeast α-mannan is a viable food source for Bacteroides thetaiotaomicron (Bt), a dominant member of the microbiota. Detailed biochemical analysis and targeted gene disruption studies support a model whereby limited cleavage of α-mannan on the surface generates large oligosaccharides that are subsequently depolymerized to mannose by the action of periplasmic enzymes. Co-culturing studies showed that metabolism of yeast mannan by Bt presents a ‘selfish’ model for the catabolism of this recalcitrant polysaccharide. This report shows how a cohort of highly successful members of the microbiota has evolved to consume sterically-restricted yeast glycans, an adaptation that may reflect the incorporation of eukaryotic microorganisms into the human diet.Article10.1038/nature13995PMC4978465openAccess