Pheromone‐induced production of antimicrobial peptides in Lactobacillus

Abstract

SummaryProduction of the bacteriocin sakacin P by Lactobacillus sake LTH673 is dependent on a secreted 19-residue peptide pheromone (IP-673). The gene encoding IP-673 (sppIP ) was identified and sequenced. SppIP was shown to be co-transcribed with genes encoding a histidine kinase (sppK ) and a response regulator (sppR ) typical for signal transduction in bacteria. Further sequencing and transcription studies have shown that IP-673 induces transcription of its own gene and of what are often considered to be all genes necessary for bacteriocin production and immunity. Studies with a reporter gene showed that the promoter in front of the sakacin P structural gene (sppA) is strictly regulated. The promoter in front of sppIP turned out to be less strictly regulated, and low basal promoter activity could be detected in uninduced cells. Bacteriocin production in Bac ¹ isolates of L. plantarum C11 could be induced by the non-cognate IP-673 only after the introduction of sppK, indicating that sppK encodes the pheromone receptor. These results show that bacteriocin production in lactobacilli is regulated using a short, strain-specific peptide pheromone. Growth conditions were shown to have considerable effects on the functionality of this regulatory mechanism.

High-level, inducible gene expression in Lactobacillus sakei and Lactobacillus plantarum using versatile expression vectors

“…The induction factor and histidine protein kinase genes are novel, but the response regulator gene is identical to the response regulator involved in the production of plantaricins by L. plantarum C11 (Diep et al, 1995). It has been shown previously that the products of the regulatory C11 genes can act on the regulated promoters in the sakacin P regulon (Brurberg et al, 1997;Risøen et al, 2000). Although the chromosomal system is not induced under the conditions used in this study (Maldonado et al, 2003(Maldonado et al, , 2004) (G. Mathiesen & V. G. H. Eijsink, unpublished observations), it is possible that low background expression of one or more of the regulatory genes affects the performance of the pSIP vectors in the L. plantarum NC8 host.…”

“…The present study based on translational fusions reveals differences that may be due to one or more subtle differences in the promoter sequences. These include a one-nucleotide exchange in the characteristic direct repeat sequences upstream of the 210 region (Brurberg et al, 1997), a one-nucleotide difference in the spacing between the putative ribosome-binding site (AGGAG in both cases) and the start codon, and sequence differences in the spacer regions. It is well known that changes in the length and/or sequence of the window between the ribosome-binding site and the start codon may affect expression Vellanoweth & Rabinowitz, 1992), and this has also been observed in an earlier variant of a P orfX -based expression system (Mathiesen et al, 2004a).…”

“…For the sakacin A-based vector the increase was approximately threefold in L. sakei Lb790, whereas no significant effect was observed in L. plantarum NC8 (pSIP304 versus pSIP302). Exchange of the P sppA promoter with the P orfX promoter from the same spp regulon (Brurberg et al, 1997;Risøen et al, 2000) clearly Fig. 2.…”

Structure-Function Analysis of Immunity Proteins of Pediocin-Like Bacteriocins: C-Terminal Parts of Immunity Proteins Are Involved in Specific Recognition of Cognate Bacteriocins

“…Six different hybrid immunity proteins were constructed from three different immunity proteins (EntA-im, LeuA-im, and OrfY-im) that have similar sequences (i.e., belong to the same group) but confer resistance to different bacteriocins (16). EntA-im and LeuA-im are the cognate immunity proteins for enterocin A and leucocin A, respectively, whereas OrfY-im is an immunity protein for which a cognate bacteriocin has not been identified (7,16). All three immunity proteins have a conserved sequence of eight amino acid residues (L-X-N-R-L-X-N-Y; six residues are identical) situated approximately in the middle of the proteins (Fig.…”

The synthesis of the bacteriocin sakacin A is a temperature-sensitive process regulated by a pheromone peptide through a three-component regulatory system

“…To exploit their potential in various applications, these compounds need to be studied in detail. We have recently shown that bacteriocin production in both Lactobacillus plantarum C11 and Lactobacillus sakei LTH673 is an inducible process, triggered by small induction factor (IF) peptides, plantaricin A and the mature product of orfY, respectively (the latter is hereafter referred to as Spp-Ph) (Diep et al, 1995(Diep et al, , 1996Eijsink et al, 1996 ;Brurberg et al, 1997). A similar regulatory mechanism has also been reported for nisin production, where nisin itself serves as the in- duction factor (Kuipers et al, 1995).…”