Table II.
Relationship between daidzin deglycosylation and induction of nolX expression in S. fredii strain USDA257
| Incubation Time | Daidzein Treatment
|
Daidzin Treatment
|
||
|---|---|---|---|---|
| Daidzein recoverya | nolX activityb | Daidzein recoverya | nolX activityb | |
| h | pmol | Miller units | pmol | Miller units |
| 12 | 413 ± 49 | 57 ± 5 | 2 ± 3 | 0 |
| 24 | 432 ± 15 | 124 ± 16 | 7 ± 1 | 0 |
| 48 | 456 ± 8 | 475 ± 15 | 13 ± 3 | 15 ± 4 |
| 72 | 374 ± 8 | 700 ± 31 | 18 ± 4 | 122 ± 1 |
| 96 | 373 ± 31 | 727 ± 64 | 20 ± 4 | 279 ± 1 |
Values are means ± sd.
a
Daidzein and daidzin were supplied at an initial concentration of 100 nm. The mean recovery of daidzein from bacteria-free, daidzein-containing control tubes was 458 ± 90 pmol. Daidzein was not recovered from bacteria-free, daidzin-containing control tubes, except at 72 h, when 3.7 pmol was detected.
b
Values from methanol-treated controls have been subtracted from those given in the table. These controls yielded an average of 8, 15, 28, 28, and 25 Miller units of β-galactosidase activity, respectively, after 12, 24, 48, 72, and 96 h of incubation.