Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Cuskin, Fiona; Lowe, Elisabeth C; Temple, Max J; Zhu, Yanping; Cameron, Elizabeth A; Pudlo, Nicholas A; Porter, Nathan T; Urs, Karthik; Thompson, Andrew J; Cartmell, Alan; Rogowski, Artur; Hamilton, Brian S; Chen, Rui; Tolbert, Thomas J; Piens, Kathleen; Bracke, Debby; Vervecken, Wouter; Hakki, Zalihe; Speciale, Gaetano; Munōz-Munōz, Jose L; Day, Andrew; Peña, Maria J; McLean, Richard; Suits, Michael D; Boraston, Alisdair B; Atherly, Todd; Ziemer, Cherie J; Williams, Spencer J; Davies, Gideon J; Abbott, D Wade; Martens, Eric C; Gilbert, Harry J
Year of Publication: 2015
Journal: Nature
Volume: 517
Issue: 7533
Pagination: 165-9
Date Published: 2015 Jan 8
Publication Language: eng
ISSN: 1476-4687
Keywords: Animals, Bacteroidetes, Biological Evolution, Carbohydrate Conformation, Diet, Enzymes, Female, Gastrointestinal Tract, Genetic Loci, Germ-Free Life, Glycoproteins, Humans, Male, Mannans, Mannose, Mice, Models, Biological, Models, Molecular, Oligosaccharides, Periplasm, Yeasts

Yeasts, which have been a component of the human diet for at least 7,000 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 the Gram-negative bacterium Bacteroides thetaiotaomicron, 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 B. thetaiotaomicron presents a 'selfish' model for the catabolism of this difficult to breakdown polysaccharide. Genomic comparison with B. thetaiotaomicron in conjunction with cell culture studies show that 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.

DOI: 10.1038/nature13995
Alternate Journal: Nature