Table 3. Effect of HHQ addition on phz1 operon expression in PA14 and lasR^– cultures.

	β-gal activity, MU
	PA14	lasR-
-HHQ	371 ± 8	78.7 ± 1.5
+HHQ	473 ± 23	83.7 ± 0.2

Cultures were assayed at 8 hr, corresponding to OD₆₀₀ 4.3-4.5. The bacteria carry a phzABC-lacZ fusion. Data correspond to averages of triplicates ± SD. MU, Miller units.