Table 2.

Effect of farnesol and tyrosol on total protease production in Egyptian isolates of P. aeruginosa.

Isolate number	Control	Tyrosol effect		Farnesol effect
	Total protease production by the isolate (U/mL)	Before normalization	After normalization	Before normalization	After normalization
1	107	75.6	−29.3	89	−16.8
2	95	61	−35.8	57.5	39.5
3	100	88.5	−11.5	80	−20
4	60.8	57.3	−5.6	10.6	82.5
5	198.8	154.6	−22.2	102	−48.7
6	22	21	−4.5	22	−0.1
7	76	60.8	−20	64	−15.8
8	102.8	85.9	−16.4	102	−0.8
9	128.9	118.2	−8.3	96	−25.5
10	147.9	115.4	−22	121.8	−17.6
11	65.5	54.2	−17.3	65	0.8
12	127	76.4	−39.8	165.4	−30.2
13	33.5	46.4	38.5	32	−4.5
14	94.5	78.4	−17	75.5	20.1
15	160	91.3	−42.9	143	−10.6
16	63.7	61.8	−3	62	−2.7
17	90	70.7	−21.4	101.7	13
18	109	100.8	−7.5	99	−9.2
19	130.7	123.8	−5.3	82	−37.3
20	163	101.5	−37.7	150	−8

The values in the control column represent the levels of total protease production by the isolates (SD = 44.3), as determined in [27], without addition of farnesol and tyrosol. The values in the columns of tyrosol and farnesol stand for either nonnormalized values (SD = 40 and 40.5 for tyrosol and farnesol, resp.) or normalized values. The latter values indicate the percent of either decrease (negative values) or increase (positive values) in the production of total protease after normalization to untreated samples (control). All values represent the mean of three independent experiments.