Kanamycin

All strains, plasmids, and primers used in this study are listed in Table 1 and 2. We used the Enterobacter cloacae type strain ATCC13047 and its derivatives for all experiments. All strains were initially grown from freezer stocks on solid Luria-Bertani (LB) agar at 37°C. Isolated colonies were used to inoculate LB at 37°C. Where applicable, kanamycin was used at 50 μg/mL, chloramphenicol at 100 μg/mL, and cecropin B (MedChemExpress, Monmouth Junction, NJ) at 20 μg/mL unless otherwise noted. For complementation experiments, 0.2% arabinose or 200 μM Isopropyl-ß-D-thiogalactopyranoside (IPTG) was used to induce plasmid-borne genes.

For the antibiotic‐induction experiments, strains carrying certain plasmids were grown overnight in LB medium at 28°C with shaking at 200 r.p.m. Overnight cultures were diluted (OD₆₀₀ = 0.2) in LB medium. Antibiotics Rtm, tetracycline (Tet), Vgm, rapamycin (Rap), lincomycin (Lin), Pnm, Cam, Lnz, telithromycin (Tel), kanamycin (Kan) and vancomycin (Van) (MedChem Express, Monmouth Junction, NJ, USA) were added as required and cultivation was continued for different times. Then, 2 ml of the cultures was harvested to assay the β‐galactosidase activity or to extract the total RNA.