TABLE 5.
Effect of various treatments on the ability of PU-15 CM to reduce phzB::lacZ expression in strain 30-84Z
| Treatment | β-Galactosidase activity |
|---|---|
| LB medium only | 389 ± 13a |
| None (CM only) | 11 ± 2 |
| Heat | 18 ± 3 |
| Pronase | 14 ± 2 |
| Proteinase K | 14 ± 3 |
| Aqueous phaseb | 22 ± 11 |
| Acidified ethyl acetate phaseb | 228 ± 5 |
a
Values are the averages of results of four replicates ± standard errors.
b
CM of PU-15 was extracted with acidified ethyl acetate, and the aqueous and the acidified ethyl acetate phases were separated. The acidified ethyl acetate phase had little effect on phzB::lacZ expression, whereas the aqueous phase remained highly inhibitory.