TABLE 2.
Effects of ccpA and ccpB mutations on the expression of a gntRK′-′lacZ fusion by various sugars on solid medium containing X-Gala
| Repressing sugar | Response of
strainb:
|
||||
|---|---|---|---|---|---|
| ST100 | ST101 | ST102 | ST103 | ST105 | |
| None | ++ | ++ | ++ | ++ | ++ |
| Glucose | − | +/− | +/− | + | + |
| Mannitol | − | + | + | ++ | ++ |
| Sucrose | +/− | + | + | ++ | ++ |
| Glycerol | ++ | ++ | ++ | ++ | ++ |
a
Cells were streaked onto LB plates containing X-Gal and 1% gluconate as well as a 1% concentration of the repressing sugar indicated and were incubated overnight at 37°C. Responses were recorded as follows: ++, dark blue; +, blue; +/−, pale blue; −, white. In the absence of gluconate, all colonies were white.
b
Strain ST100 was the wild type; strains ST101, ST102, ST103, and ST105 carried defective genes ccpA, ccpB, ccpA and ccpB, and ptsH1, respectively.