Bovine glycomacropeptide promotes the growth of Bifidobacterium longum ssp. infantis and modulates its gene expression

Abstract

Bovine milk glycomacropeptide (GMP) is derived from κ-casein, with exclusively o-linked glycosylation. Glycomacropeptide promoted the growth of Bifidobacterium longum ssp. infantis in a concentration-dependent manner, and this activity was lost following periodate treatment of the GMP (GMP-P), which disables biological recognition of the conjugated oligosaccharides. Transcriptional analysis of B. longum ssp. infantis following exposure to GMP revealed a substantial response to GMP relative to bacteria treated with GMP-P, with a greater number of differentially expressed transcripts and larger fold changes versus the control. Therefore, stimulation of B. longum ssp. infantis growth by GMP is intrinsically linked to the peptide's O-linked glycosylation. The pool of differentially expressed transcripts included 2 glycoside hydrolase (family 25) genes, which were substantially upregulated following exposure to GMP, but not GMP-P. These GH25 genes were present in duplicated genomic islands that also contained genes encoding fibronectin type III binding domain proteins and numerous phage-related proteins, all of which were also upregulated. Homologs of this genomic arrangement were present in other Bifidobacterium species, which suggest it may be a conserved domain for the utilization of glycosylated peptides. This study provides insights into the molecular basis for the prebiotic effect of bovine milk GMP on B. longum ssp. infantis.

Comparative Genomics of Lactobacillus crispatus from the Gut and Vagina Reveals Genetic Diversity and Lifestyle Adaptation

“…This might require more in-depth exploration of the specific role of CBM in vagina-derived L. crispatus. GH25 has a role in facilitating cell division and in defense, as a lysozyme involved in cell wall and peptidoglycan catabolism [56]. GH73 encodes β-N-acetylglucosaminidases that cleave the β-1,4 glycosidic linkage between the N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) residues of bacterial cell wall peptidoglycan (PG) [57].…”

Molecular Insights Into O-Linked Glycan Utilization by Gut Microbes

“…Transcriptomic analysis of the GMP utilization revealed the induction of two intracellular GH25 enzymes, a family related to bacterial lysozymes, and a solute binding protein from an ABC transporter (O'Riordan et al, 2018). These results provide new insights regarding the adaptations of this probiotic microorganism for a milk-derived substrate.…”

“…Strikingly, B. infantis has been shown to grow vigorously using GMP (O'Riordan et al, 2018). A 20.6 ± 3.6% increase in OD 600nm was observed in the mid-exponential phase of B. longum ssp.…”

Glycomacropeptide: Biological Activities and Uses

“…infantis in a dose-dependent manner and modulates its genes expression. Again, they found that the effect was lost with periodate GMP, suggesting that its activity is due to the oligosaccharides present in the molecule [38].…”