TABLE 1.
Strains and plasmids used in this study
| Strain or plasmid | Relevant feature(s) | Source or reference |
|---|---|---|
| Bacterial strains | ||
| E. coli DH5α | Host strain for general cloning | 36 |
| E. coli BL21 | Expression host | Novagen |
| S. thermophilus ST2017 | Wild-type strain isolated from fermented dairy products | Preserved in the laboratory |
| S. thermophilus ST2017ΔcodY | ΔcodY mutant strain | This study |
| S. thermophilus ST2017ΔcodY-codYexp | codYSt overexpression strain | This study |
| S. thermophilus ST2017ΔgdhA | gdhA inactive in S. thermophilus ST2017 | This study |
| S. thermophilus ST2017ΔcodYΔgdhA | gdhA inactive in S. thermophilus ST2017ΔcodY | This study |
| Plasmids | ||
| pG+host9 | Ermr; pWV01 replicon (temp sensitive) | 22 |
| pG+host-Up-Down | Ermr; codYSt knockout vector | This study |
| pG+host-gdhAin | Ermr; vector with inactive gdhA | This study |
| pSEC | Cmr; nisin-inducible expression vector | 37 |
| pSEC-codY | codYSt under the control of the nox promoter | This study |