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

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dc.contributor.advisor Stanton, Catherine en
dc.contributor.advisor van Sinderen, Douwe en
dc.contributor.author O'Connell, Kerry Joan
dc.date.accessioned 2014-04-02T15:15:12Z
dc.date.issued 2014
dc.date.submitted 2014
dc.identifier.citation O'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.endpage 334
dc.identifier.uri http://hdl.handle.net/10468/1502
dc.description.abstract The 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.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Kerry J. O'Connell en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Conjugated linoleic acid en
dc.subject Prebiotic en
dc.subject LacI en
dc.subject ROK en
dc.subject Regulation en
dc.subject Megaplasmid en
dc.subject.lcsh Bifidobacterium en
dc.subject.lcsh Microbial metabolism en
dc.subject.lcsh Plasmids--Genetics en
dc.title Investigations into selective metabolic aspects of bifidobacteria: carbohydrate metabolism, fatty acid biosynthesis and plasmid biology en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.description.version Accepted Version
dc.contributor.funder TOMAR Trust, Ireland en
dc.description.status Not peer reviewed en
dc.internal.school Microbiology en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Both hard copy thesis and e-thesis en
ucc.workflow.supervisor d.vansinderen@ucc.ie
dc.internal.conferring Summer Conferring 2014


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