TABLE 1.
Characterization of streptomycin- and rifampin-resistant mutants of P. agaridevorans T-3040
| Strain | Antibiotic (μg/ml) used for selection | Mutationa |
Amino acid substitution | Resistance (μg/ml)b |
CITase activity (U/ml)c | |||
|---|---|---|---|---|---|---|---|---|
| rsmG | rpsL | rpoB | Streptomycin | Rifampin | ||||
| T-3040 (wild type) | 20 | 0.5 | ≥1 | |||||
| YT362 | Streptomycin (30) | 118–121→CGAA→Δ | Frameshift (position 40→stop codon) | 150 | 0.5 | 90 ± 41 | ||
| YT359 | Streptomycin (30) | 119G→1-bp deletion | Frameshift | 150 | 0.5 | 109 ± 13 | ||
| YT361 | Streptomycin (30) | 148G→AA | Frameshift | 150 | 0.5 | 96 ± 10 | ||
| YT360 | Streptomycin (30) | 544G→T | Glu182→stop codon | 150 | 0.5 | 107 ± 11 | ||
| YT373 | Streptomycin (30) | 685C→T | Arg229→Cys | 150 | 0.5 | 113 ± 16 | ||
| YT382 | Streptomycin (100) | 167A→G | Lys56→Arg | 3000 | 0.5 | 140 ± 38 | ||
| YT374 | Streptomycin (100) | 192G→T | Lys64→Asn | 50 | 0.5 | 114 ± 8 | ||
| YT420 | Streptomycin (100) | 301A→G | Lys101→Glu | 1000 | 0.5 | 35 ± 16 | ||
| YT421 | Streptomycin (100) | 302A→G | Lys101→Arg | 500 | 0.5 | 99 ± 11 | ||
| YT385 | Streptomycin (100) | 302A→T | Lys101→Met | 500 | 0.5 | 109 ± 16 | ||
| YT386 | Streptomycin (100) | 314G→A | Gly105→Asp | 200 | 0.5 | 72 ± 12 | ||
| YT504 | Rifampin (2) | 1393T→C | Ser465→Pro | 20 | 5 | 32 ± 18 | ||
| YT510 | Rifampin (2) | 1405C→A | Gln469→Lys | 20 | 300 | 197 ± 62 | ||
| YT399 | Rifampin (2) | 1406A→T | Gln469→Leu | 20 | 30 | 215 ± 67 | ||
| YT393 | Rifampin (2) | 1406A→G | Gln469→Arg | 20 | 300 | 174 ± 3 | ||
| YT506 | Rifampin (2) | 1415A→T | Asp472→Leu | 20 | 2 | 3 ± 20 | ||
| YT395 | Rifampin (2) | 1433C→A | Ala478→Asp | 20 | 30 | 59 ± 12 | ||
| YT398 | Rifampin (2) | 1460C→A | Ser487→Thr | 20 | 30 | 110 ± 25 | ||
| YT394 | Rifampin (2) | 1460C→T | Ser487→Phe | 20 | 30 | 80 ± 8 | ||
a
Numbered from the start codon of the open reading frame of B. subtilis.
b
Determined after incubating for 3 days on NG plates.
c
Strains were grown in LB-Dex medium at 30°C for 3 days. One unit of CITase was defined as the amount of enzyme capable of producing 1 nmol of the sum of CI-7, CI-8, and CI-9 per min from dextran at pH 5.5 at 40°C. Experiments were performed in triplicate, and the data are expressed as means ± standard deviations.