Table 2.
MICs in mg/l for the S. lividans lrm–mgt knockout strain
| Antibiotic
|
S. lividans (lrm−mgt−) | ||||||
|---|---|---|---|---|---|---|---|
| Control | rlmAI (G745) | rlmAII (G748) | tlrD (A2058) | rlmAI + tlrD | rlmAII + tlrD | ermE (2A2058) | |
| Tylosin | 2 | 2 | 8 | 8 | 8 | 512 | 8,000 |
| Erythromycin A | 2 | 2 | 2 | 64 | 32 | 64 | 8,000 |
| Lincomycin | 32 | 32 | 32 | 16,000 | 16,000 | 16,000 | 16,000 |
Cells contained the plasmid-encoded methyltransferases rlmAI (Acinetobacter), rlmAII (S. fradiae), tlrD (S. fradiae), and ermE (Saccharopolyspora erythraea), and combinations of these genes. Other homologues of the rlmA genes gave the same MIC values. Coexpression of any of the rlmA genes with ermE did not alter the ermE-resistance levels. Controls contain the empty pHJL 401 plasmid. MICs were additionally measured in S. lividans WT cells (see Table 5, which is published as supporting information on the PNAS web site).