TABLE 1.
Bacterial strains and plasmids used in this study.
| Strain/plasmid | Descriptiona | Source/Reference |
| Bacterial strain | ||
| E. coli ESS | Indicator strain for Ceph-C bioassays | Wang et al., 2004 |
| E. coli ET12567/pUZ8002 | Non-methylating conjugation host carrying helper plasmid pUZ8002 (CmlR and KanR) | Kieser et al., 2000 |
| E. coli DH5α | General laboratory cloning host | Promega |
| K. pneumoniae ATCC 15380 | Indicator strain for CA bioassays (PenR) | ATCC |
| S. clavuligerus ATCC27064 | Wild-type CA producer | ATCC |
| S. clavuligerus ΔnocE | nocE null mutant | This study |
| S. clavuligerus pIJ8668-ermEp∗-nocE | Strain constitutively expressing nocE | This study |
| S. jumonjinensis NRRL 5741 | Wild-type CA producer | Jensen and Paradkar, 1999 |
| S. katsurahamanus T272 | Wild type CA producer | Jensen and Paradkar, 1999 |
| Plasmids | ||
| pGEMT-Easy | Plasmid for cloning PCR products | Promega |
| pIJ8668-ermEp∗ | Conjugative Streptomyces suicide vector containing ermEp∗ for chromosomal promoter insertion (AprR) | (Tahlan et al., 2017) |
| pIJ8668-ermEp∗-nocE | pIJ8668-ermEp∗ containing a portion of the 5′ end of nocE from S. clavuligerus (AprR) | This study |
| pIJ12738 | Conjugative Streptomyces suicide vector containing an I-SceI site for gene targeting (AprR) | Fernández-Martínez and Bibb, 2014 |
| pIJ12738-nocE-UP-DN | pIJ12738 containing regions upstream and downstream of nocE from S. clavuligerus (AprR) | This study |
| pIJ12742 | Plasmid expressing the Meganuclease I-SceI in Streptomyces for gene disruption (AprR and TsrR) | Fernández-Martínez and Bibb, 2014 |
aAprR, apramycin resistance; CmlR, chloramphenicol resistance; KanR, kanamycin resistance; PenR, penicillin G resistance; and TsrR, thiostrepton resistance.