Linked Life Data

19560223

Source:http://linkedlifedata.com/resource/pubmed/id/19560223

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-7-20
pubmed:abstractText
Conjugative transfer of plasmid-associated properties is routinely used to generate food-grade derivatives of lactococcal starter strains with improved technological traits. However, the introduction of one or more plasmids in a single strain is likely to impose a burden on regular cell metabolism and may affect the growth characteristics of the transconjugant culture. The aim of this study was to evaluate the impact of the 60.2-kb plasmid pMRC01 (encoding for an abortive infection bacteriophage resistance system and production of the anti-microbial, lacticin 3147) on starter performance. Five lactococcal strains (L. lactis HP, 255A, SK1, 712 and IL1403) and their pMRC01-containing derivatives were compared in terms of technological properties, including analysis of growth, acidification and autolysis rates. The transconjugants exhibited lower specific growth rates and higher generation times compared to the parental strains when grown at 30 degrees C in glucose-M17, but the presence of pMRC01 did not significantly affect the acidification capacity of strains in 11% reconstituted skimmed milk and synthetic media. Levels of lactate dehydrogenase were two-fold higher in supernatants of transconjugants than in those of parental strains, after 24 and 72 h of growth at 30 degrees C in glucose-M17, suggesting that the presence of pMRC01 somehow accelerates and promotes cellular autolysis. Analysis by flow cytometry following live/dead staining confirmed this result by showing larger populations of injured and dead cells in pMRC01-carrying cultures compared to the parental strains. The results of this study reveal that the plasmid pMRC01 places a burden on lactococcal host metabolism, which is associated with an increased cell permeability and autolysis, without significantly affecting the acidification capacity of the starter. While the magnitude of these effects appears to be strain dependent, the production of the bacteriocin lacticin 3147 may not be involved.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1879-3460
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
133
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
217-24
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
The presence of pMRC01 promotes greater cell permeability and autolysis in lactococcal starter cultures.
pubmed:affiliation
Teagasc, Moorepark Food Research Centre, County Cork, Ireland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't