TABLE 2.
Determination of mec- and bla-mediated repression and induction of mecA expression
| Strain | Relevant genotypea | β-Galactosidase activityb with CBAP at:
|
Fold inductionc | |
|---|---|---|---|---|
| 0 μg/ml | 10 μg/ml | |||
| GO450TF::630 | mecR1+mecI+ (c) | 355 ± 94 | 4,404 ± 386 | 12 |
| GO450TF::630 + pGO621C | mecR1+mec1+ (c) | 54 ± 12.5 | 4,291 ± 459 | 80 |
| mecR1+mec1+ (p) | ||||
| GO450TF::630 + pCH2278 | mecR1+mecI (c) | 187 ± 87.5 | 10,597 ± 893 | 57 |
| blaR1+blaI+ (p) | ||||
| GO450TF::630ΔI | mecR1 ΔmecI (c) | 23,265 ± 1,972 | 21,461 ± 2,691 | 0 |
| GO450TF::630ΔI + pGO621C | mecR1 ΔmecI (c) | 195 ± 95 | 5,676 ± 124 | 29 |
| mecR1+mec1+ (p) | ||||
| GO450TF::630ΔI + pCH2278 | mecR1 ΔmecI (c) | 431 ± 174 | 18,811 ± 182 | 44 |
| blaR1+blaI+ (p) | ||||
a
c, chromosomal; p, plasmid borne.
b
Miller units per milligram of protein per hour. Means of at least three experiments ± standard deviation.
c
Fold increase in activity as calculated by the activity obtained in the presence of mecI following a 2-h exposure to CBAP divided by the activity in the absence of mecI and/or blaI.