Submitted to: Nature Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2008
Publication Date: 11/26/2008
Citation: Sela, D.A., Chapman, J., Adeuya, A., Kim, J.H., Chen, F., Whitehead, T.R., Lapidus, A., Rokhsar, D.S., Lebrilla, C.B., German, J.B., Price, N.P., Richardson, P.M., Mills, D.A. 2008. The Genome Sequence of Bifidobacterium longum subsp. infantis Reveals Adaptations for Milk Utilization Within the Infant Microbiome. Proceedings of the National Academy of Sciences. 105(48):18964-18969. Interpretive Summary: The human gastrointestinal tract is rapidly colonized following birth by beneficial microbes, often dominated by bifidobacteria in breast-fed infants. In this paper, the complete genome sequence of Bifidobacterium longum ssp. infantis is reported, and reflects a metabolic strategy for the use of oligosaccharide sugars found selectively in human milk. Several genes encoding binding proteins and permeases are predicted to be active on milk oligosaccharides, and the mechanism underlying milk utilization is supported by conservation of sugar-related genes in multiple B. longum ssp. infantis strains. Also, our examination of cellular metabolism has shown milk oligosaccharide usage via the central sugar metabolic pathway in B. longum ssp. infantis. This work will be of great advantage for evaluating the benefits of bifidobacterium gut bacteria, and improve our understanding of functional prebiotic nutrition in children.
Technical Abstract: Following birth, the breast-fed infant gastrointestinal tract is rapidly colonized by a microbial consortium often dominated by bifidobacteria. Accordingly, the complete genome sequence of Bifidobacterium longum ssp. infantis ATCC15697 reflects a competitive nutrient-utilization strategy targeting milk-borne molecules which lack a nutritive value to the neonate. Several chromosomal loci reflect potential adaptation to the infant host including a 43 kbp cluster encoding catabolic genes, extracellular solute binding proteins, and permeases predicted to be active on milk oligosaccharides. An examination of in vivo metabolism has detected the hallmarks of milk oligosaccharide utilization via the central fermentative pathway using metabolomic and proteomic approaches. Finally, conservation of gene clusters in multiple isolates corroborates the genomic mechanism underlying milk utilization for this infant-associated phylotype.