Metabolism of human milk oligosaccharides by infant-associated bifidobacteria
type: CreativeWork
description: Bifidobacteria are Gram-positive, anaerobic bacteria belonging to the Actinobacteria phylum, and are commensals of the mammalian, avian and occasionally insect gastrointestinal tracts. In humans, bifidobacteria are typically highly abundant in the intestinal microbiota of healthy breastfed infants, in particular a small number of infant-associated species, including Bifidobacterium breve, Bifidobacterium longum subsp. infantis, Bifidobacterium bifidum and Bifidobacterium kashiwanohense. A key adaptation, facilitating the establishment and dominance of these species in the breastfed infant gut microbiota, is the ability to consume and metabolise specific glycans only found in breastmilk, and indigestible for the infant, known as Human Milk Oligosaccharides (HMOs). Fascinatingly, the adaptation to utilise HMO as a substrate by bifidobacteria is almost exclusively reserved for infant-associated species, and even more fascinatingly, these species have developed strikingly varying strategies for the consumption of different HMO components. Strategies for the metabolism of various individual HMO glycans in different species of bifidobacteria shall be discussed in this thesis, with particular focus on B. breve UCC2003 and the novel isolate B. kashiwanohense APCKJ1. Chapter II of this thesis is comprised of work elucidating the mechanisms and components of LNT, LNnT and LNB utilisation pathways in Bifidobacterium breve UCC2003. Using a combination of experimental approaches, the enzymatic machinery involved in the metabolism of LNT, LNnT and LNB is identified and characterised. Furthermore, the distribution across the genus, of homologs for the key genes involved in the utilisation of these substrates, is analysed. Chapter III focuses on identifying the regulatory network responsible for the transcriptional control of the genes involved in LN(n)T and LNB metabolism, as described in Chapter II. Three transcriptional regulators and corresponding operator and associated (induc…
abstract: Bifidobacteria are Gram-positive, anaerobic bacteria belonging to the Actinobacteria phylum, and are commensals of the mammalian, avian and occasionally insect gastrointestinal tracts. In humans, bifidobacteria are typically highly abundant in the intestinal microbiota of healthy breastfed infants, in particular a small number of infant-associated species, including Bifidobacterium breve, Bifidobacterium longum subsp. infantis, Bifidobacterium bifidum and Bifidobacterium kashiwanohense. A key adaptation, facilitating the establishment and dominance of these species in the breastfed infant gut microbiota, is the ability to consume and metabolise specific glycans only found in breastmilk, and indigestible for the infant, known as Human Milk Oligosaccharides (HMOs). Fascinatingly, the adaptation to utilise HMO as a substrate by bifidobacteria is almost exclusively reserved for infant-associated species, and even more fascinatingly, these species have developed strikingly varying strategies for the consumption of different HMO components. Strategies for the metabolism of various individual HMO glycans in different species of bifidobacteria shall be discussed in this thesis, with particular focus on B. breve UCC2003 and the novel isolate B. kashiwanohense APCKJ1. Chapter II of this thesis is comprised of work elucidating the mechanisms and components of LNT, LNnT and LNB utilisation pathways in Bifidobacterium breve UCC2003. Using a combination of experimental approaches, the enzymatic machinery involved in the metabolism of LNT, LNnT and LNB is identified and characterised. Furthermore, the distribution across the genus, of homologs for the key genes involved in the utilisation of these substrates, is analysed. Chapter III focuses on identifying the regulatory network responsible for the transcriptional control of the genes involved in LN(n)T and LNB metabolism, as described in Chapter II. Three transcriptional regulators and corresponding operator and associated (induc…
author: James, Kieran
language: en
keywords: Microbiology, Probiotics, Prebiotics, Bifidobacteria, Infant Health, Human milk oligosaccharides, Carbohydrate metabolism, Molecular biology
license: http://creativecommons.org/licenses/by-nc-nd/3.0/
date published: 2018
date modified: 2026-07-24T01:48:18Z
provider: University College Cork
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University College Cork

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10468/6097