Plasmid biology of natural Lactococcus lactis strains and molecular mechanisms of bacteriophage-host interaction

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dc.contributor.advisor Ross, R. Paul
dc.contributor.advisor Fitzgerald, Gerald F.
dc.contributor.advisor McAuliffe, Olivia
dc.contributor.author Fallico, Vincenzo
dc.date.accessioned 2011-07-05T09:03:37Z
dc.date.available 2011-07-05T09:03:37Z
dc.date.issued 2011-03
dc.date.submitted 2011-03
dc.identifier.citation Fallico, V. 2011. Plasmid biology of natural Lactococcus lactis strains and molecular mechanisms of bacteriophage-host interaction. PhD Thesis, University College Cork. en
dc.identifier.uri http://hdl.handle.net/10468/323
dc.description.abstract Lacticin 3147, enterocin AS-48, lacticin 481, variacin, and sakacin P are bacteriocins offering promising perspectives in terms of preservation and shelf-life extension of food products and should find commercial application in the near future. The studies detailing their characterization and bio-preservative applications are reviewed. Transcriptomic analyses showed a cell wall-targeted response of Lactococcus lactis IL1403 during the early stages of infection with the lytic bacteriophage c2, which is probably orchestrated by a number of membrane stress proteins and involves D-alanylation of membrane lipoteichoic acids, restoration of the physiological proton motive force disrupted following bacteriophage infection, and energy conservation. Sequencing of the eight plasmids of L. lactis subsp. cremoris DPC3758 from raw milk cheese revealed three anti-phage restriction/modification (R/M) systems, immunity/resistance to nisin, lacticin 481, cadmium and copper, and six conjugative/mobilization regions. A food-grade derivative strain with enhanced bacteriophage resistance was generated via stacking of R/M plasmids. Sequencing and functional analysis of the four plasmids of L. lactis subsp. lactis biovar. diacetylactis DPC3901 from raw milk cheese revealed genes novel to Lactococcus and typical of bacteria associated with plants, in addition to genes associated with plant-derived lactococcal strains. The functionality of a novel high-affinity regulated system for cobalt uptake was demonstrated. The bacteriophage resistant and bacteriocin-producing plasmid pMRC01 places a metabolic burden on lactococcal hosts resulting in lowered growth rates and increased cell permeability and autolysis. The magnitude of these effects is strain dependent but not related to bacteriocin production. Starters’ acidification capacity is not significantly affected. Transcriptomic analyses showed that pMRC01 abortive infection (Abi) system is probably subjected to a complex regulatory control by Rgg-like ORF51 and CopG-like ORF58 proteins. These regulators are suggested to modulate the activity of the putative Abi effectors ORF50 and ORF49 exhibiting topology and functional similarities to the Rex system aborting bacteriophage λ lytic growth. en
dc.description.sponsorship Irish Research Council for Science Engineering and Technology (Embark initiative) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.relation.isbasedon Fallico, V., O. McAuliffe, G.F. Fitzgerald, C. Hill and R.P. Ross. (2011). The potential of lacticin 3147, enterocin AS-48, lacticin 481, variacin and sakacin P for food biopreservation. Pages 100-121. In: Lacroix, C., (Ed.), Protective cultures, antimicrobial metabolites and bacteriophages for food and beverage biopreservation. Woodhead Publishing Limited, Cambridge. ISBN: 978 1 84569 669
dc.relation.isbasedon Fallico, V., O. McAuliffe, G.F. Fitzgerald, C. Hill and R.P. Ross. (2009). The presence of pMRC01 promotes greater cell permeability and autolysis in lactococcal starter cultures. International Journal of Food Microbiology. 133:217–224. doi: 10.1016/j.ijfoodmicro.2009.04.029
dc.relation.uri http://www.woodheadpublishing.com/en/book.aspx?bookID=1634
dc.relation.uri http://dx.doi.org/10.1016/j.ijfoodmicro.2009.04.029
dc.relation.uri http://library.ucc.ie/record=b2027887~S0
dc.rights © 2011, Vincenzo Fallico en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Natural strains en
dc.subject.lcsh Lactococcus lactis en
dc.subject.lcsh Plasmids en
dc.subject.lcsh Bacteriophages en
dc.title Plasmid biology of natural Lactococcus lactis strains and molecular mechanisms of bacteriophage-host interaction 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 en
dc.contributor.funder Irish Research Council for Science Engineering and Technology en
dc.contributor.funder Teagasc
dc.description.status Not peer reviewed en


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