Glycan Utilization and Cross-Feeding Activities by Bifidobacteria

Bifidobacteria represent one of the first colonizers of the mammalian gut, where such colonization is facilitated by their saccharolytic capabilities. Genomic analyses of bifidobacteria have revealed intriguing genetic strategies employed by these bacteria to access a variety of dietary and host-produced glycans. Bifidobacterial genome evolution therefore represents a fascinating example of how their chromosomes were molded to contain a large number of genes involved in carbohydrate metabolism. One of the reasons as to why bifidobacteria are such dominant and prevalent members of the (early) microbiota is that they may access glycans in the gut through mutualistic cross-feeding or resource-sharing activities, which is indicative of 'social behavior' among bifidobacterial strains. Bifidobacteria represent key members of the gut microbiota in the early phases of life of animals that subject their offspring to parental care.The first microbiota assemblage is believed to play pivotal roles in human health, both in infancy and at later stages of life.Dietary and/or host-derived glycans represent a potent evolutionary force that has shaped the bifidobacterial pan-genome. In silico and functional genomic analyses of bifidobacterial genomes revealed species-specific adaptation to a glycan-rich gut environment.A key determinant of microbial dynamics in the gut microbiota results from nutrient competition and sharing.Bifidobacteria play an important ecological role in shaping the gut microbiome.Bifidobacteria exhibit social behavior through carbohydrate resource sharing in the gut.