TABLE 3.

Effect of PQ on bacterial isolates in and on a surface matrix

Treatmenta		Growth (normalized to control)
Location	PQ concn	α-Proteobacteria		Bacteroidetes		γ-Proteobacteria
						Pseudoalteromonas		Vibrio
		Target 1	Target 2	Target 1	Target 2	Target 1	Target 2	Target 1	Target 2
Surface of matrix	Ethanol controlb	110	98	98	101	88	115	95	86
	1 μM	153	92	102	113	108	119	117	121
	10 μM	127	70	93	81	93	94	100	94
	50 μM	27	42	32	29	38	30	87	41
	100 μM	18	31	24	27	11	50	62	4
In matrix	Ethanol controlb	86	84	94	99	94	95	89	97
	50 nM	131	70	107	107	100	99	100	104
	100 nM	82	58	97	107	99	98	97	98
	1 μM	61	61	103	104	97	94	95	87
	10 μM	26	54	68	63	65	67	87	81
	50 μM	20	29	62	61	69	67	64	72
	100 μM	26	50	57	50	51	49	38	49

^aTarget cells were placed either on or in an agar matrix treated with PQ in a 96-well microtiter plate and incubated overnight. The effects of PQ on two known targets belonging to each of four groups were examined. Growth was measured by determining the density for each treatment and then was normalized to the growth in the blank control, which was defined as 100.

^bThe control contained 0.08% ethanol. The PQ concentrations used ranged from 0.5 nM to 100 μM, and only the results for concentrations which produced significant inhibition are shown.