TABLE 2.
Effects of adenine and adenosine on the expression of pbuE′-lacZ transcriptional fusions in B. subtilis mutants defective in the metabolism of adenine
| Strain | Relevant genotype | PbuE status | β-Galactosidase activity (U/mg of protein) witha:
|
||
|---|---|---|---|---|---|
| No purine | 150-μg/ml adenine | 300-μg/ml adenosine | |||
| LJ24 | amyE::[pLJ24 pbuE′-lacZ (cat)] | Wild type | 0.6 | 25 | 4 |
| LJ32 | pbuE::pLJ32 (erm) | Deficient | 1.1 | 267 | 41 |
| ED501 | amyE::[pLJ24 pbuE′-lacZ (cat)] ade | Wild type | 0.4 | 32 | 12 |
| ED502 | amyE::[pLJ24 pbuE′-lacZ (cat)] ade apt | Wild type | 10 | 31 | 17 |
| ED503 | pbuE::pLJ32 (erm) ade | Deficient | 1.0 | 279 | 155 |
| ED504 | pbuE::pLJ32 (erm) ade apt | Deficient | 176 | 249 | 179 |
Values are means of results from three experiments. The variation was less than 25%. Cells were grown in minimal medium. B. subtilis was grown in Spizizen minimal salt medium (15) supplemented with 0.2% l-glutamate, 1 mg of thiamine/liter, and 0.4% glucose as a carbon source (11). Amino acids, when required, were added to give a final concentration of 40 mg/liter. Activity of β-galactosidase was determined in cell extracts as described previously (2). All enzyme determinations were repeated at least three times. One unit of enzyme activity is equal to 1 nmol of product formed per min. Total protein was determined by the Lowry method.