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Nature. 2015 Jan 8;517(7533):165-169. doi: 10.1038/nature13995.

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

Author information

1
Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K.
2
Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA.
3
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
4
Department of Chemistry, University of York, York YO10 5DD, U.K.
5
School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
6
Dept. of Pharmaceutical Chemistry, University of Kansas School of Pharmacy, 2095 Constant Ave, Lawrence, KS 66047, USA.
7
Oxyrane, Ghent, Belgium.
8
Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB, Canada.
9
Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
10
USDA, Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, Iowa, USA.
#
Contributed equally

Abstract

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.

PMID:
25567280
PMCID:
PMC4978465
DOI:
10.1038/nature13995
[Indexed for MEDLINE]
Free PMC Article

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