Genetic diversity within
L. sakei has been assessed through the use of specifically designed
PCR primers for detection using
randomly amplified polymorphic DNA, or by multi-locus sequence typing.
Bacteriocin genes Bacteriocin genes are located either on chromosomes or on
bacteriocinogenic plasmids. Strain
5 produces a plasmid-encoded bacteriocin that is identical to
sakacin P, as well as two chromosomally encoded bacteriocins, which were designated
sakacin T and
sakacin X.
LasX is a transcriptional regulator of the
lactocin S biosynthetic genes in strain
L45 of
Lactobacillus sakei.
Other genes In strain
LTH677, a starter organism used in meat fermentation, there is an oxygen-dependent regulation of the expression of the
catalase gene
katA. In strain
LTH681, the stress operon
dnaK has been characterized in 1999 as a heat shock protein gene. There is only one gene (
IdhL) responsible for the
lactic fermentation.
Plasmids A
Theta-type plasmid has been characterized in
Lactobacillus sakei in 2003. It is a potential basis for Low-Copy-Number vectors in lactobacilli. Vectors for inducible gene expression in
L. sakei can be constructed. The key elements of these vectors are a
regulatable promoter involved in the production of the bacteriocins
sakacin A and
sakacin P and the genes encoding the cognate
histidine protein kinase and
response regulator that are necessary to activate this promoter upon induction by a peptide pheromone.
Genome The genome of the meat-borne lactic acid bacterium
Lactobacillus sakei 23K has been published in 2005. It is composed of 1884661 nucleotides forming 1879 protein genes and 84 RNA genes. == References ==