Takane Katayama

A genomic library of Bifidobacterium bifidum constructed in Escherichia coli was screened for the ability to hydrolyze the alpha-(1-->2) linkage of 2'-fucosyllactose, and a gene encoding 1,2-alpha-l-fucosidase (AfcA) was isolated. The afcA gene was found to comprise 1,959 amino acid residues with a predicted molecular mass of 205 kDa and containing a signal peptide and a membrane anchor at the N and C termini, respectively. A domain responsible for fucosidase activity (the Fuc domain; amino acid

Breast-fed infants often have intestinal microbiota dominated by bifidobacteria in contrast to formula-fed infants. We found that several bifidobacterial strains produce a lacto-N-biosidase that liberates lacto-N-biose I (Galbeta1,3GlcNAc; type 1 chain) from lacto-N-tetraose (Galbeta1,3GlcNAcbeta1,3Galbeta1,4Glc), which is a major component of human milk oligosaccharides, and subsequently isolated the gene from Bifidobacterium bifidum JCM1254. The gene, designated lnbB, was predicted to encode a

The infant's gut microbiome is generally rich in the <i>Bifidobacterium</i> genus. The mother's milk contains natural prebiotics, called human milk oligosaccharides (HMOs), as the third most abundant solid component after lactose and lipids, and of the different gut microbes, infant gut-associated bifidobacteria are the most efficient in assimilating HMOs. Indeed, the fecal concentration of HMOs was found to be negatively correlated with the fecal abundance of <i>Bifidobacterium</i> in infants.

The human gut microbiota established during infancy has persistent effects on health. In vitro studies have suggested that human milk oligosaccharides (HMOs) in breast milk promote the formation of a bifidobacteria-rich microbiota in infant guts; however, the underlying molecular mechanism remains elusive. Here, we characterized two functionally distinct but overlapping fucosyllactose transporters (FL transporter-1 and -2) from <i>Bifidobacterium longum</i> subspecies <i>infantis</i>. Fecal DNA

The breast-fed infant intestine is often colonized by particular bifidobacteria, and human milk oligosaccharides (HMOs) are considered to be bifidogenic. Recent studies showed that Bifidobacterium longum subsp. infantis can grow on HMOs as the sole carbon source. This ability has been ascribed to the presence of a gene cluster (HMO cluster-1) contained in its genome. However, the metabolism of HMOs by the organism remains unresolved because no enzymatic studies have been completed. In the presen

Fucosyloligosaccharides have great therapeutic potential. Here we present a new route for synthesizing a Fucα1,2Gal linkage by introducing glycosynthase technology into 1,2‐α‐ l ‐fucosidase. The enzyme adopts a unique reaction mechanism, in which asparagine‐423 activated by aspartic acid‐766 acts as a base while asparagine‐421 fixes both a catalytic water and glutamic acid‐566 (an acid) in the proper orientations. Glycosynthase activity of N421G, N423G, and D766G mutants was examined using β‐fuc

Lactation is a common feeding strategy of eutherian mammals, but its functions go beyond feeding the neonates. Ever since Tissier isolated bifidobacteria from the stool of breast-fed infants, human milk has been postulated to contain compounds that selectively stimulate the growth of bifidobacteria in intestines. However, until relatively recently, there have been no reports to link human milk compound(s) with bifidobacterial physiology. Over the past decade, successive studies have demonstrated

Certain species of the genus <i>Bifidobacterium</i> represent human symbionts. Many studies have shown that the establishment of symbiosis with such bifidobacterial species confers various beneficial effects on human health. Among the more than ten (sub)species of human gut-associated <i>Bifidobacterium</i> that have significantly varied genetic characteristics at the species level, <i>Bifidobacterium bifidum</i> is unique in that it is found in the intestines of a wide age group, ranging from i