TABLE 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Description | Source or reference |
|---|---|---|
| H. ducreyi strain 35000HP | Human-passaged variant of strain 35000; parental strain | 41 |
| E. coli strains | ||
| DH5α and TOP10 | Strains used for general cloning procedures | Invitrogen |
| DY380 | DH10B derivative containing a defective λ prophage in which the red, bet, and gam genes are controlled by the temp-sensitive λcI857 repressor | 29 |
| Plasmids | ||
| pT | pLS88 derivative containing the tetracycline (tet) controlled expression system | 27 |
| pDG8 | pT derivative containing rpoE under control of the tet system | This study |
| pSPECR | Vector containing the spectinomycin resistance cassette | 28 |
| pDG9 | pT derivative containing the rpoE coding region and spectinomycin resistance cassette from pSPECR | This study |
| pDG10 | pT derivative containing the spectinomycin resistance cassette from pSPECR | This study |
| pDG11 | pT derivative containing a 3×-FLAG-tagged RpoE and a spectinomycin resistance cassette | This study |
| pRB157 | pLS88 derivative containing an ΩAmp cartridge followed by a BglII site for insertion of putative promoter sequences and a promoterless GFP cassette derived from pGreenTIR | 10 |
| pDG12 | pRB157 derivative containing the putative dsbA promoter region | This study |
| pDG13 | pRB157 derivative containing the putative degP promoter region | This study |
| pDG14 | pRB157 derivative containing the putative hfq promoter region | This study |
| pDG15 | pRB157 derivative containing the putative rpoE promoter region | This study |
| pDG16 | pRB157 derivative containing the putative rpoH promoter region | This study |
| pLS88 | H. ducreyi shuttle vector | 42 |
| pACYC177 | Low-copy-number H. ducreyi shuttle vector with a P15A origin of replication | New England Biolabs |
| pDG17 | pACYC177 derivative containing the tetracycline-regulated RpoE expression system | This study |
| pKF1 | pRB157 derivative containing the putative lspB promoter region | 10 |
| pDG18 | pDG16 derivative in which the first putative RpoE-dependent promoter is mutagenized from AAC to TTT at the −35 region | This study |
| pDG19 | pDG16 derivative in which the second putative RpoE-dependent promoter is mutagenized from AAC to TTT at the −35 region | This study |