Bioengineering of nisin to enhance functionality against dairy pathogens

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dc.contributor.advisor Hill, Colin en
dc.contributor.advisor Cotter, Paul D. en
dc.contributor.advisor Ross, R. Paul en Healy, Brian 2016-06-03T15:01:24Z 2014 2014
dc.identifier.citation Healy, B. C. 2014. Bioengineering of nisin to enhance functionality against dairy pathogens. PhD Thesis, University College Cork. en
dc.identifier.endpage 163 en
dc.description.abstract The bacteriocin class of antimicrobial peptides have emerged as a viable alternative to at least partially fill the void created by the end of the golden age of antibiotic discovery. Along with this potential use in a clinical setting, bacteriocins also play an important role as bio-preservatives in the food industry. This thesis focuses on a specific bacteriocin group, the lantibiotics (Lanthionine-containing antibiotics). Their numerous methods of appliance in a food setting and how their gene-encoded nature can be modified to improve on overall bioactivity and functionality are explored here. The use of a lantibiotic (lacticin 3147) producing starter culture to control the Crohn’s disease-linked pathogen Mycobacterium paratuberculosis was assessed in a raw milk cheese. Although lacticin 3147 production did not effectively control the pathogen, the study provided an impetus to employ a variety of PCR-based mutagenesis techniques with a view to the creation of enhanced lantibiotic derivatives. Through the use of these techniques, a number of enhanced derivatives were generated from the ‘hinge’ region of the nisin peptide. Furthermore, a derivative in which the three hinge amino acids were replaced with three alanines represents the first enhanced derivative of nisin to have been designed through a rational process. This derivative also formed the backbone for the creation of an active, trypsin resistant, variant. Through the employment of further mutagenesis methods a derivative was created with potential use as an oral anti-bacterial in the future. Finally a number of lead nisin derivatives were investigated to assess their anti- Streptococcus agalactiae ability, a mastitis associated pathogen. Also a system was developed to facilitate the large scale production of these candidates, or other nisin derivatives, from dairy substrates. en
dc.description.sponsorship Department of Agriculture, Food and the Marine, Ireland (Food Institutional Research Measure (08/RD/C/691)) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Brian C. Healy en
dc.rights.uri en
dc.subject Nisin en
dc.subject Lacticin 3147 en
dc.subject Bacteriocin en
dc.subject Lantibiotic en
dc.subject Mutagenesis en
dc.subject Bioengineering en
dc.subject Streptococcus agalactiae en
dc.subject Mycobacterium avium subspecies paratuberculosis en
dc.subject Lactococcus lactis en
dc.title Bioengineering of nisin to enhance functionality against dairy pathogens 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 Department of Agriculture, Food and the Marine, Ireland en
dc.contributor.funder Teagasc en
dc.description.status Not peer reviewed en Microbiology en Teagasc 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 No en
dc.thesis.opt-out false
dc.check.chapterOfThesis 4,5
dc.check.embargoformat Both hard copy thesis and e-thesis en
dc.internal.conferring Summer 2015 en

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© 2014, Brian C. Healy Except where otherwise noted, this item's license is described as © 2014, Brian C. Healy
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