Production of plantaricin NC8 by Lactobacillus plantarum NC8 is induced in the presence of different types of gram-positive bacteria

Abstract

1 2Lactobacillus plantarum NC8 was shown to produce plantaricin NC8 (PLNC8), a recently 3 purified and genetically characterized inducible class IIb bacteriocin, only when it was co-4 cultured with other Gram-positive bacteria. Among 82 strains belonging to the genera 5

Induction of Plantaricin Production inLactobacillus plantarumNC8 after Coculture with Specific Gram-Positive Bacteria Is Mediated by an Autoinduction Mechanism

“…Although these operons are very similar to those for bacteriocin production in L. plantarum C11, a new regulatory operon of the three-component type has been found. Homologous and heterologous expression of the novel inducer peptide (PLNC8IF) of this operon supports our previous observations in the sense that an autoinduction mechanism is activated in NC8 as a response to the presence of specific bacteria in its own environment (34). This observation has been confirmed by reverse transcription-PCR (RT-PCR) analysis of the expression of the bacteriocin and regulatory operons found in NC8.…”

“…Along with the induced bacteriocin PLNC8, an autoin-ducing activity was also produced after exposure of NC8 cultures to the inducing conditions. In this case, the CFS from a previously induced (bac ϩ ) NC8 culture was able to induce bacteriocin production in a fresh NC8 single culture (34). This observation was confirmed by sequence analysis of the promoter region of the plNC8BAC operon (33), which maintains the consensus of promoters of class II bacteriocin operons whose expression is dependent on an autoinduction mechanism (36,42).…”

“…L. plantarum NC8, kindly provided by Lars Axelsson (MATFORSK, Norwegian Food Research Institute, Osloveien, Norway), has been described recently as producing an inducible two-peptide bacteriocin named PLNC8 in response to cocultivation with specific gram-positive bacteria (33,34). It was propagated in MRS broth (Oxoid, Basingstoke, Hampshire, England) at 30°C without shaking.…”

“…Induction of bacteriocin production in L. plantarum NC8 can be accomplished either (i) by coculturing with specific gram-positive bacteria (such as L. lactis MG1363), (ii) by addition of heat-killed cells from some of these inducing bacteria, or (iii) by addition of CFS showing inducing activity (33,34).…”

“…Interestingly, this bacteriocin was produced by L. plantarum NC8 only after cocultivation with specific grampositive strains or the addition of heat-killed cells from some of the inducing strains (33,34). However, no cell-free supernatants (CFS) from any of the inducing strains had any effect (34).…”