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

• Autores: Fiona Cuskin, Elisabeth C. Lowe, Max J. Temple, Yanping Zhu, Elizabeth A. Cameron, Nicholas A. Pudlo
• Localización: Nature: International weekly journal of science, ISSN 0028-0836, Vol. 517, Nº 7533, 2015, págs. 165-169
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • 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.