TABLE 1.
Strains and plasmids used in this study
| Strain or plasmid | Genotype or description | Source or reference |
|---|---|---|
| Strains | ||
| L. monocytogenes | ||
| LO28 | Virulent L. monocytogenes reference strain | 67 |
| LM2000 | ΔclpB | This study |
| LM2001 | ΔctsR::aphA3 | This study |
| B. subtilis | ||
| 168 | trpC2 | Laboratory stock |
| QB4991 | trpC2 ΔctsR amyE::(′lacZ aphA3) | 10 |
| QB8059 | trpC2 amyE::(clpB′-bgaB cat) ΔctsR | pDL73/74→QB4991 |
| QB8060 | trpC2 amyE::(clpB′-bgaB cat) ΔctsR thrC::(pxylctsRLmospc) | pxyl59/60→QB8059 |
| Plasmids | ||
| pMAD | pE194 derivative with a thermosensitive origin of replication for deletion replacement of genes in gram-positive bacteria | M. Arnaud and M. Débarbouillé, unpublished |
| pMAD ΔclpB | pMAD derivative, for deletion replacement of the L. monocytogenes clpB gene | This study |
| pMAD ΔctsR | pMAD derivative, for deletion replacement of the L. monocytogenes ctsR gene | This study |
| pDL | Integrative plasmid for constructing transcriptional fusions with the B. stearothermophilus bgaB gene | 70 |
| pDL73/74 | pDL derivative carrying a clpB′-bgaB fusion | This study |
| pXT | Plasmid allowing integration at the thrC locus and expression from the PxylA xylose-inducible promoter | 9 |
| pxyl59/60 | pXT derivative carrying the ctsR coding sequence of L. monocytogenes | 42 |