Investigations into selective metabolic aspects of bifidobacteria: carbohydrate metabolism, fatty acid biosynthesis and plasmid biology

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dc.check.embargoformatBoth hard copy thesis and e-thesisen
dc.check.entireThesisEntire Thesis Restricted
dc.check.opt-outNot applicableen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorStanton, Catherineen
dc.contributor.advisorvan Sinderen, Douween
dc.contributor.authorO'Connell, Kerry Joan
dc.contributor.funderTOMAR Trust, Irelanden
dc.date.accessioned2014-04-02T15:15:12Z
dc.date.issued2014
dc.date.submitted2014
dc.description.abstractThe gastrointestinal tract (GIT) is a diverse ecosystem, and is colonised by a diverse array of bacteria, of which bifidobacteria are a significant component. Bifidobacteria are Gram-positive, saccharolytic, non-motile, non-sporulating, anaerobic, Y-shaped bacteria, which possess a high GC genome content. Certain bifidobacteria possess the ability to produce conjugated linoleic acid (CLA) from linoleic acid (LA) by a biochemical pathway that is hypothesised to be achieved via a linoleic isomerase. In Chapter two of this thesis it was found that the MCRA-specifying gene is not involved in CLA production in B. breve NCFB 2258, and that this gene specifies an oleate hydratase involved in the conversion of oleic acid into 10-hydroxystearic acid. Prebiotics are defined as non-digestible food ingredients that beneficially affect the host by selectively stimulating growth and/or activity of one or a limited number of bacteria in the colon. Key to the development of such novel prebiotics is to understand which carbohydrates support growth of bifidobacteria and how such carbohydrates are metabolised. In Chapter 3 of this thesis we describe the identification and characterisation of two neighbouring gene clusters involved in the metabolism of raffinose-containing carbohydrates (plus related carbohydrate melibiose) and melezitose by Bifidobacterium breve UCC2003. The fourth chapter of this thesis describes the analysis of transcriptional regulation of the raf and mel clusters. In the final experimental chapter two putative rep genes, designated repA7017 and repB7017, are identified on the megaplasmid pBb7017 of B. breve JCM 7017, the first bifidobacterial megaplasmid to be reported. One of these, repA7017, was subjected to an in-depth characterisation. The work described in this thesis has resulted in an improved understanding of bifidobacterial fatty acid and carbohydrate metabolism, Furthermore, attempts were made to develop novel genetic tools.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationO'Connell, K. J. 2014. Investigations into selective metabolic aspects of bifidobacteria: Carbohydrate metabolism, fatty acid biosynthesis and plasmid biology. PhD Thesis, University College Cork.en
dc.identifier.endpage334
dc.identifier.urihttps://hdl.handle.net/10468/1502
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2014, Kerry J. O'Connellen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectConjugated linoleic aciden
dc.subjectPrebioticen
dc.subjectLacIen
dc.subjectROKen
dc.subjectRegulationen
dc.subjectMegaplasmiden
dc.subject.lcshBifidobacteriumen
dc.subject.lcshMicrobial metabolismen
dc.subject.lcshPlasmids--Geneticsen
dc.thesis.opt-outfalse
dc.titleInvestigations into selective metabolic aspects of bifidobacteria: carbohydrate metabolism, fatty acid biosynthesis and plasmid biologyen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
ucc.workflow.supervisord.vansinderen@ucc.ie
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