Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism

Article

关键词: CARBOHYDRATE-ACTIVE ENZYMES;    POLYSACCHARIDE UTILIZATION;    BACTERIA;    CATABOLISM;    MICROBIOTA;    INSIGHTS;    COMPLEX;    FAMILY;    STARCH;   

DOI  :  10.1038/nature13995

来源: SCIE

【 摘 要 】

Yeasts, which have been a component of the human diet for at least 7,000 years, possess an elaborate cell wall alpha-mannan. The influence of yeast mannan on the ecology of the human microbiota is unknown. Here we show that yeast alpha-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 alpha-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.

【 授权许可】

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