Utilization of galactooligosaccarides by Bifidobacterium longum subsp. infantis isolates

Department of Food Science and Technology, University of California Davis, 1 Shields Ave., Davis, CA 95616, USA
Food Microbiology (Impact Factor: 3.33). 04/2013; 33(2):262-70. DOI: 10.1016/
Source: PubMed


Prebiotics are non-digestible substrates that stimulate the growth of beneficial microbial populations in the intestine, especially Bifidobacterium species. Among them, fructo- and galacto-oligosaccharides are commonly used in the food industry, especially as a supplement for infant formulas. Mechanistic details on the enrichment of bifidobacteria by these prebiotics are important to understand the effects of these dietary interventions. In this study the consumption of galactooligosaccharides was studied for 22 isolates of Bifidobacterium longum subsp. infantis, one of the most representative species in the infant gut microbiota. In general all isolates showed a vigorous growth on these oligosaccharides, but consumption of larger galactooligosaccharides was variable. Bifidobacterium infantis ATCC 15697 has five genes encoding β-galactosidases, and three of them were induced during bacterial growth on commercial galactooligosaccharides. Recombinant β-galactosidases from B. infantis ATCC 15697 displayed different preferences for β-galactosides such as 4' and 6'-galactobiose, and four β-galactosidases in this strain released monosaccharides from galactooligosaccharides. Finally, we determined the amounts of short chain fatty acids produced by strain ATCC 15697 after growth on different prebiotics. We observed that biomass and product yields of substrate were higher for lactose and galactooligosaccharides, but the amount of acids produced per cell was larger after growth on human milk oligosaccharides. These results provide a molecular basis for galactooligosaccharide consumption in B. infantis, and also represent evidence for physiological differences in the metabolism of prebiotics that might have a differential impact on the host.

Download full-text


Available from: Santiago Ruiz-Moyano Seco de Herrera, Sep 01, 2014
1 Follower
94 Reads
  • Source
    • "The relevance of iTregs to the development of atopy in the first year of life is less clear. However, the probiotic system of milk featured by milk-derived bifidobacteria regulates the appropriate development of the infant’s gut microbiome by providing bifidobacteria as well as bacterial nursing factors such as oligosaccharides of human milk [118-121]. The appropriate composition of milk fatty acids may have further impacts on mTORC1-mediated Treg differentiation [115-117]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This article provides a new view of the cellular mechanisms that have been proposed to explain the links between infant formula feeding and the development of atopy and obesity. Epidemiological evidence points to an allergy- and obesity-preventive effect of breastfeeding. Both allergy and obesity development have been traced back to accelerated growth early in life. The nutrient-sensitive kinase mTORC1 is the master regulator of cell growth, which is predominantly activated by amino acids. In contrast to breastfeeding, artificial infant formula feeding bears the risk of uncontrolled excessive protein intake overactivating the infant's mTORC1 signalling pathways. Overactivated mTORC1 enhances S6K1-mediated adipocyte differentiation, but negatively regulates growth and differentiation of FoxP3(+) regulatory T-cells (Tregs), which are deficient in atopic individuals. Thus, the "early protein hypothesis" not only explains increased mTORC1-mediated infant growth but also the development of mTORC1-driven diseases such as allergy and obesity due to a postnatal deviation from the appropriate axis of mTORC1-driven metabolic and immunologic programming. Remarkably, intake of fresh unpasteurized cow's milk exhibits an allergy-preventive effect in farm children associated with increased FoxP3(+) Treg numbers. In contrast to unprocessed cow's milk, formula lacks bioactive immune-regulatory microRNAs, such as microRNA-155, which plays a major role in FoxP3 expression. Uncontrolled excessive protein supply by formula feeding associated with the absence of bioactive microRNAs and bifidobacteria in formula apparently in a synergistic way result in insufficient Treg maturation. Treg deficiency allows Th2-cell differentiation promoting the development of allergic diseases. Formula-induced mTORC1 overactivation is thus the critical mechanism that explains accelerated postnatal growth, allergy and obesity development on one aberrant pathway.
    Allergy Asthma and Clinical Immunology 07/2014; 10(1):37. DOI:10.1186/1710-1492-10-37 · 2.03 Impact Factor
  • Source
    • "Bifidobacterium longum has a large number of genes related to oligosaccharide metabolism (Schell et al. 2002) and the probiotic B. longum subsp. infantis ATCC 15697 gained increasing attention due to its ability to utilize HMOs (Sela et al. 2008; Asakuma et al. 2011) and other β-galactosides including prebiotic GOS (Garrido et al. 2013). We recently reported that the GH42 enzyme Bga42A of B. longum subsp. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Glycoside hydrolase family 42 (GH42) includes β-galactosidases catalyzing the release of galactose from the non-reducing end of different β-D-galactosides. Health-promoting probiotic bifidobacteria, which are important members of the human gastrointestinal tract microbiota, produce GH42 enzymes enabling utilization of β-galactosides exerting prebiotic effects. However, insight into the specificity of individual GH42 enzymes with respect to substrate monosaccharide composition, glycosidic linkage and degree of polymerization is lagging. Kinetic analysis of natural and synthetic substrates resembling various milk and plant galactooligosaccharides, distinguishes the three GH42 members, Bga42A, Bga42B, and Bga42C, encoded by the probiotic Bifidobacterium longum subsp. infantis ATCC 15697, and revealed the glycosyl residue at subsite +1 and its linkage to the terminal galactose at subsite-1 to be key specificity determinants. Bga42A thus prefers the β1-3-galactosidic linkage from human milk and other β1-3- and β1-6-galactosides with glucose or galactose situated at subsite +1. By contrast Bga42B very efficiently hydrolyses 4-galactosyllactose (Galβ1-4Galβ1-4Glc) as well as 4-galactobiose (Galβ1-4Gal) and 4-galactotriose (Galβ1-4Galβ1-4Gal). The specificity of Bga42C resembles that of Bga42B, but the activity was one order of magnitude lower. Based on enzyme kinetics, gene organization and phylogenetic analyses Bga42C is proposed to act in the metabolism of arabinogalactan-derived oligosaccharides. The distinct kinetic signatures of the three GH42 enzymes correlate to unique sequence motifs denoting specific clades in a GH42 phylogenetic tree providing novel insight into GH42 subspecificities. Overall the data illustrate the metabolic adaptation of bifidobacteria to the β-galactoside rich gut niche and emphasize the importance and diversity of β-galactoside metabolism in probiotic bifidobacteria.
    Glycobiology 11/2013; 24(2). DOI:10.1093/glycob/cwt104 · 3.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: subsp. is a common member of the intestinal microbiota in breast-fed infants and capable of metabolizing human milk oligosaccharides (HMO). To investigate the bacterial response to different prebiotics, we analyzed both cell wall associated and whole cell proteins in Proteins were identified by LC-MS/MS followed by comparative proteomics to deduce the protein localization within the cell. Enzymes involved in the metabolism of lactose, glucose, galactooligosaccharides, fructooligosaccharides and HMO were constitutively expressed exhibiting less than two-fold change regardless of the sugar used. In contrast, enzymes in N-Acetylglucosamine and sucrose catabolism were induced by HMO and fructans, respectively. Galactose-metabolizing enzymes phosphoglucomutase, UDP-glucose 4-epimerase and UTP glucose-1-P uridylytransferase were expressed constitutively, while galactokinase and galactose-1-phosphate uridylyltransferase, increased their expression three fold when HMO and lactose were used as substrates for cell growth. Cell wall-associated proteomics also revealed ATP-dependent sugar transport systems associated with consumption of different prebiotics. In addition, the expression of 16 glycosyl hydrolases revealed the complete metabolic route for each substrate. Mucin, which possesses O-glycans that are structurally similar to HMO did not induced the expression of transport proteins, hydrolysis or sugar metabolic pathway indicating do not utilize these glycoconjugates.
    PLoS ONE 02/2013; 8(2):e57535. DOI:10.1371/journal.pone.0057535 · 3.23 Impact Factor
Show more