Production of bioactive metabolites by intestinal bacteria

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dc.contributor.advisor Fitzgerald, Gerald F. en
dc.contributor.advisor Stanton, Catherine en
dc.contributor.advisor Ross, R. Paul en Marques, Tatiana Milena 2017-01-09T12:55:00Z 2017-01-09T12:55:00Z 2013 2013
dc.identifier.citation Marques, T. M. 2013. Production of bioactive metabolites by intestinal bacteria. PhD Thesis, University College Cork. en
dc.identifier.endpage 287 en
dc.description.abstract The adult intestinal microbiota comprises a microbial ecosystem of approximately 100 trillion microorganisms, with specific bacterial communities holding distinct metabolic capabilities. Bacteria produce a range of bioactive compounds to survive unfavourable stimuli and to interact with other organisms, and generate several bioactive products during degradation of dietary constituents the host is not capable of digesting. This thesis addressed the impact of feeding potential probiotic bacteria and other dietary strategies such as pure fatty acids and prebiotics, on gut microbiota composition, short chain fatty acid (SCFA) production and modulation of metabolism in animal models. In the first experimental chapter (Chapter 2) a gas chromatography method for the quantification of SCFA was optimized and applied in the analysis of caecal samples obtained in animal studies described in other chapters of this thesis. In Chapter 3, t10, c12 CLA supplementation was shown to significantly alter murine gut microbiota composition and SCFA production rather than no supplementation. These changes were suggested to be extra factors affecting host lipid metabolism. Chapter 4 described the contrasting effects of CLA-producing strains, Bifidobacterium breve DPC 6330 and B. breve NCIMB 702258, on murine fat distribution/composition and gut microbiota composition, suggesting that these changes were most likely strain-dependent. In Chapter 5, dietary GABA-producing strain Lactobacillus brevis DPC 6108 was shown to significantly increase (p<0.05) serum insulin in healthy rats, leading to a second experiment using a type 1 diabetes rat model. Lb. brevis DPC 6108 administration did not change insulin levels in diabetic rats, but attenuated high levels of glucose when compared to diabetic control. However, an auto-immune-induced diabetes model was suggested as a better model to study GABA-related effects on diabetes. In Chapter 6 bovine milk oligosaccharides, 6’sialyllactose and Beneo Orafti P95 oligofructose supplementations were associated with depletion or reduction of less favourable bacteria, demonstrating that ingestion of these oligosaccharides might be a safe and effective approach to modulate populations of the intestinal microbiota. In Chapter 7 (General discussion) the major findings of all studies were reviewed and discussed. en
dc.description.sponsorship Science Foundation Ireland (SFI Grant 07/CE/B1368) en
dc.format.mimetype application/pdf en
dc.language English en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2013, Tatiana Milena Marques. en
dc.rights.uri en
dc.subject Microbiota en
dc.subject Probiotic en
dc.subject Prebiotic en
dc.subject Short chain fatty acids en
dc.subject Fatty acids en
dc.subject Metabolites en
dc.title Production of bioactive metabolites by intestinal bacteria en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral Degree (Structured) en
dc.type.qualificationname PhD (Food Science and Technology) en
dc.internal.availability Full text available en No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Science Foundation Ireland en
dc.contributor.funder Alimentary Health Ltd, Ireland en
dc.description.status Not peer reviewed en Alimentary Pharmabotic Centre en Microbiology en Teagasc en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
dc.internal.conferring Spring 2014 en

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© 2013, Tatiana Milena Marques. Except where otherwise noted, this item's license is described as © 2013, Tatiana Milena Marques.
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