VSE knjižnice (vzajemna bibliografsko-kataložna baza podatkov COBIB.SI)
  • Expression of nisin genes in cheese : a quantitative real-time polymerase chain reaction approach
    Trmčić, Aljoša ...
    The role of bacteriocins in different environments has not been throughly explained, mainly because of the difficulties related to the detection of their production. Nisin, an antimicrobial peptide ... produced by Lactococus lactis has a long history of safe use in food products and has been studied from many aspects of genetics, biosynthesis, immunity, regulation, and mode of action. Still, some aspects concerning the dynamics of nisin gene expression remain unknown, especially in complex media like cheese. The main objective of the present study was to quantify in a cheese-like medium the expression of nisin genes in L. lactis M78, a well-characterized nisin A producer isolated from raw milk. The expression of all 11 genes involved in nisin biosynthesis was evaluated during cheese production by real time reverse transcription-PCR. Total RNA was extracted from cheeses using a direct extraction method without prior separation of microbial cells. The M78 strain grew well in experimental cheeses, producing detectable amounts of nisin after 4 h fermentation. The presence of nisin as an activator modified both the expression of nisin genes and the accumulation of active nisin. Four groups could be distinguised based on gene expression as a function of time: nisA, nisFEG, nisRK and nisBTCIP. Based on nisin-producing strain growth, nisin activity, founction of nisin genes, and their location, correlations were established that contribute to the explanation of regulation of nisin biosynthesis and immunity. This study is the first in which the evolution of bacteriocin gene transcripts has been quantified rigorously in a cheese-like medium.
    Vir: Journal of dairy science. - ISSN 0022-0302 (Vol. 94, no. 1, 2011, str. 77-85)
    Vrsta gradiva - članek, sestavni del
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 2799240

vir: Journal of dairy science. - ISSN 0022-0302 (Vol. 94, no. 1, 2011, str. 77-85)
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