In general, a bifidobacteria-predominant microbiota is established in breastfed infant guts, and such microbiota formation is believed to be beneficial to host health. Since the isolation of Bifidobacterium sp. in 1899, research has been conducted to elucidate how bifidobacteria proliferate in the infant gut and which components, if present, in breastmilk promote their growth. In the 1950s, human milk oligosaccharides (HMOs) were reported to act as a growth factor for bifidobacteria. However, until relatively recently, the structural complexity of HMOs has hampered the elucidation of the molecular mechanism underlying HMOs-mediated selective growth of bifidobacteria. In the early 21st century, systematic understanding of the HMO utilization mechanism of bifidobacteria rapidly advanced. In this chapter, we describe the historical aspects and recent progress of the research on HMOs and bifidobacteria. ...and more
Heparan sulfate (HS) is present as a component of proteoglycans on cell surfaces and in the extracellular matrix in most animal species including Hydra, Caenorhabditis, Drosophila, and humans. HS chains are structurally heterogeneous, being composed of densely sulfated regions, or sulfated domains, connected by mostly nonsulfated and N-acetyl-rich regions. HS regulates various physiological processes by the interaction with numerous proteins such as growth factors, morphogens, cytokines, enzymes, and extracellular matrix proteins. The binding specificity of HS for each functional protein is thought to be dependent on the structure of the sulfated domain. ...and more
