Table 1 Bacterial strains and plasmids used in this study

Strains

 E. coli

  DH5α

Host strain used for general subcloning

[61]

  MC1061

Host strain used for subcloning with Lc. lactis derived pNZ8048 vector; recA positive strain

Mobitec, Göttingen, Germany

 Lactobacillus plantarum

  423

Probiotic with multiple adhesion genes and a plantaricin bacteriocin producer; forms part of the entiro™ probiotic; originally isolated from sorghum beer

Cipla Medpro (Pty.) Ltd.

  423 pNZmazFnisRK

Contains the pNZmazFnisRK plasmid; Cm^R

This study

 Enterococcus mundtii

  ST4SA

Probiotic with multiple adhesion genes and a mundticin bacteriocin producer; forms part of the entiro™ probiotic; originally isolated from soybeans

Cipla Medpro (Pty.) Ltd.

  ST4SA pNZmazFnisRK

Contains the pNZmazFnisRK plasmid; Cm^R

This study

 Lactococcus lactis

  pNZ9000

Standard host strain for nisin regulated gene expression; harbors the nisR and nisK nisin regulatory genes integrated into the pepN gene locus

Mobitec, Göttingen, Germany

  pNZ9000 pNZmazF

Contains the pNZmazF plasmid; Cm^R

This study

Plasmids

 pNZ8048

Broad-host range vector; E. coli shuttle vector; LAB expression vector containing nisin A inducible-promoter (PnisA); Cm^R

Mobitec, Göttingen, Germany; [32]

 pGKV223D

E. coli/LAB shuttle vector; LAB expression vector with L23 promoter; Em^R

University of Gröningen, The Netherlands

 pNZnisRK

pNZ8048 vector carrying the nisR and nisK regulatory genes for cloning in LAB strains that do not have the regulatory genes integrated onto the chromosome; Cm^R

This study

 pNZmazF

pNZ8048 vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter; Cm^R

This study

 pNZmazFnisRK

pNZnisRK vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter; Cm^R

This study

 pNZmazFnisRKerm

pNZ8048nisRK vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter and the erm gene; Cm^R, Em^R

This study

 pBluescriptKS

PCR cloning vector; Amp^R

Stratagene, California, USA.

 pKSFRT

pBluescriptKS plasmid carrying two flippase (FLP) recombination target sequences (FRT) in a direct repeat orientation; Amp^R

This study

 pKSFRTErm

pBluesriptKS plasmid carrying the erm gene flanked by two FRT sequences in a direct repeat orientation; Em^R, Amp^R

This study

 pGKVPldhFLP

pGKV223D vector carrying the flippase (FLP) gene downstream of the constitutive L. plantarum 423 lactate dehydrogenase gene Pldh promoter; Em^R

This study

 pNZasRNA_repAnisRK

pNZmazFnisRK vector carrying a 350 bp asRNA_repA transcript downstream of the nisin-inducible PnisA promoter; Cm^R

This study

 pNZasFLPasRNA_repA

pNZasRNA_repAnisRK vector carrying the flippase (FLP) gene downstream of the constitutive L. plantarum 423 lactate dehydrogenase gene Pldh promoter; Cm^R

This study