TABLE 1.
Bacterial strains and plasmids used in this study
| Strain or plasmid | Characteristics | Reference(s) |
|---|---|---|
| Strains | ||
| S. avermitilis ATCC31267 | Wild-type strain (avg avermectin production, 40-60 mg liter−1) | 9 |
| S. avermitilis ATCC31780 | High-producing strain derived from ATCC 31267 (avg avermectin production, 160-200 mg liter−1) | 9 |
| S. avermitilis L-9 | Semi-industrial strain derived from ATCC 31267 (avg avermectin production, 400-600 mg liter−1) | 9 |
| S. lividans TK21 | Cloning host (str-6 SLP2− SLP3−) | 16, 26 |
| E. coli DH5α, JM109 | General cloning hosts | 21 |
| Plasmids | ||
| pIJ702 | Streptomyces cloning vector with mel gene (100-300 copies) | 12, 13 |
| pIJ487 | Streptomyces cloning vector (100-300 copies) | 13 |
| pIJ61 | Streptomyces cloning vector (4-5 copies) | 13, 25 |
| pIJ941 | Streptomyces cloning vector (1-2 copies) | 13, 14 |
| pUC18, pUC19 | E. coli cloning and sequencing vectors | 21 |
| pHP45Ωaac | Source of aacC4 gene | 5 |
| pHP45Ωaac′ | Site-directed mutated aacC4 gene (aac′) without XhoI site | This study |
| pPRA2 | pIJ702 containing 8.0-kb S2 fragment at BglII site | This study |
| pPRA4 | pIJ702 containing 3.6-kb SacI-PstI fragment (S4) of S1 | This study |
| pNS1 | pIJ487 containing 0.7-kb BamHI fragment (NS1) of S1 | This study |
| pNS2 | pIJ487 containing 3.3-kb SacI fragment (NS2) of S1 | This study |
| pNS3 | pIJ487 containing 1.8 kb SacI fragment (NS3) of S1 | This study |
| pNS4 | pIJ487 containing 3.2-kb SacI-BamHI fragment (NS4) of S1 | This study |
| pUC-S18 | pUC19 containing 1.8-kb SacI fragment (NS3) of S1 | This study |
| pUC-S33 | pUC19 containing 3.3-kb SacI fragment (NS2) of S1 | This study |
| pUC-S36 | pUC19 containing 3.6-kb SacI-PstI fragment (NS4) of S1 | This study |
| pMS4 | pIJ61 containing 2.7-kb BamHI-PstI fragment of S1 | This study |
| pLS4 | pIJ941 containing 3.6-kb EcoRI-PstI fragment of pUC-S36 | This study |
| pS2S | pUC19 containing 1.8-kb SphI fragment of S4 | This study |
| pUC19-tsr | pUC19 containing tsr gene on BclI fragment at BamHI site | This study |
| pS2S-tsr | pUC-S36 containing tsr gene isolated from pUC19-tsr | This study |
| pS2S-tsr-aac | pS2S-tsr containing PCR-amplified aac′ gene at XhoI site of orfX | This study |