TABLE 3.

Effect of rpoS mutation on P. aeruginosa PAO1 exoproducts^a

Exoproduct	Activity in strain:		% Relative activity
	PAO1 (RpoS+)	SS24 (RpoS−)
Exotoxin A	1,302 ± 46	660 ± 20	50.7
Elastase	161 ± 6	126 ± 2	78.6
LasA protease	0.587 ± 0.002	0.518 ± 0.014	88.3
Phospholipase C	33.45 ± 0.65	32.97 ± 0.82	98.6
Pyocyanin	0.347	0.716	206.3
Pyoverdine	0.511	0.755	147.7

^aExotoxin A activity is measured in counts per minute per 10 μl of supernatant. Elastase activity is measured as the increase in A₄₉₅ minute⁻¹ gram of protein⁻¹. LasA protease activity is measured as the rate of decrease in A₅₉₅ minute⁻¹ milligram of protein⁻¹. Phospholipase C activity is measured as the increase in OD₄₀₅ minute⁻¹ milligram of protein⁻¹. The pyocyanin level was measured as OD₆₉₅ and the pyoverdine level was measured as OD₄₆₀ following excitation at OD₄₀₀ (see Materials and Methods for details). The relative activity was calculated as follows: (activity of the rpoS mutant/activity of the parent) × 100. Values are means ± standard deviations.