TABLE 2.
Expression of the amtB::gusA fusion in different genetic backgrounds
| Strainb | β-Glucuronidase activity (U)a with indicated N source
|
|||
|---|---|---|---|---|
| 10 mM Asp | 2 mM NH4+ | 20 mM NH4+ | N2 | |
| FAJ301 | 3 | 2 | 9 | 0 |
| 7194 | 2 | 5 | 8 | 2 |
| 7148 | 1 | 4 | 6 | 0 |
| Sp7 | 123 | 95 | 16 | 75 |
a
β-Glucuronidase activity was measured after overnight incubation in minimal medium containing one of the four nitrogen sources. Units of activity were calculated as described by Miller (49). The values shown are the means of at least three independent replicates.
b
For a description of the strains, see Table 1.