Table 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Description | Reference or source |
|---|---|---|
| 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; CmR | 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; CmR | 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; CmR | This study |
| Plasmids | ||
| pNZ8048 | Broad-host range vector; E. coli shuttle vector; LAB expression vector containing nisin A inducible-promoter (PnisA); CmR | Mobitec, Göttingen, Germany; [32] |
| pGKV223D | E. coli/LAB shuttle vector; LAB expression vector with L23 promoter; EmR | 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; CmR | This study |
| pNZmazF | pNZ8048 vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter; CmR | This study |
| pNZmazFnisRK | pNZnisRK vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter; CmR | This study |
| pNZmazFnisRKerm | pNZ8048nisRK vector carrying the E. coli mazF toxin gene under the control of the PnisA promoter and the erm gene; CmR, EmR | This study |
| pBluescriptKS | PCR cloning vector; AmpR | Stratagene, California, USA. |
| pKSFRT | pBluescriptKS plasmid carrying two flippase (FLP) recombination target sequences (FRT) in a direct repeat orientation; AmpR | This study |
| pKSFRTErm | pBluesriptKS plasmid carrying the erm gene flanked by two FRT sequences in a direct repeat orientation; EmR, AmpR | This study |
| pGKVPldhFLP | pGKV223D vector carrying the flippase (FLP) gene downstream of the constitutive L. plantarum 423 lactate dehydrogenase gene Pldh promoter; EmR | This study |
| pNZasRNA_repAnisRK | pNZmazFnisRK vector carrying a 350 bp asRNA_repA transcript downstream of the nisin-inducible PnisA promoter; CmR | This study |
| pNZasFLPasRNA_repA | pNZasRNA_repAnisRK vector carrying the flippase (FLP) gene downstream of the constitutive L. plantarum 423 lactate dehydrogenase gene Pldh promoter; CmR | This study |
CmR: chloramphenicol resistance; EmR: erythromycin resistance; AmpR: ampicillin resistance