TABLE 3.
Effects of ccpA and ccpB mutations on the expression of a xylA-lacZ fusion by various sugars on solid medium containing X-Gala
| Repressing sugar | Response of
strainb:
|
||||||
|---|---|---|---|---|---|---|---|
| MD164 | ST131 | ST132 | ST133 | ST137 | ST138 | ST139 | |
| None | ++ | ++ | ++ | ++ | ++ | ++ | ++ |
| Glucose | − | + | − | ++ | ++ | + | + |
| Mannitol | +/− | + | +/− | ++ | ++ | + | + |
| Sucrose | − | + | − | ++ | ++ | + | + |
a
Cells were streaked onto LB plates containing X-Gal and 1% xylose 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 xylose, all colonies were white.
b
Strain MD164 was the wild type; the other strains carried defective genes as follows: ST131, ccpA; ST132, ccpB; ST133, ccpA and ccpB; ST137, ccpA and ccpB; ST138, ccpA and orf126; ST139, ccpA and orf184.