TABLE 4.

Effect of ampR mutation on pyocyanin production and LasA staphylolytic and LasB elastase activity

Strain	Pyocyanin productiona		LasA activityb		Elastase activityc
	Noninduced	Inducedd	Noninduced	Inducedd	Noninduced	Inducedd
PAO1	0.3 ± 0.2	2.3 ± 0.2	0.310 ± 0.065	0.317 ± 0.059	41.7 ± 1.1	105.0 ± 24.0
PAOampR	2.9 ± 0.8f	3.3 ± 0.6	1.109 ± 0.099f	0.951 ± 0.045f	32.8 ± 2.3	30.7 ± 1.7f
PAOampR/pSJ06e	0.1 ± 0.0g	1.4 ± 0.3	0.188 ± 0.055g	0.186 ± 0.019g	56.5 ± 1.5	90.5 ± 8.4g

^aPyocyanin concentrations were expressed as micrograms of pyocyanin produced per microgram of total protein.

^bLasA activity was expressed as change in OD₆₀₀ per hour per microgram of protein.

^cElastase activity was expressed as change in OD₄₉₅ per microgram of protein.

^dInduction was carried out using 500 μg/ml of benzylpenicillin.

^eThe plasmid pSJ06 is a derivative of low-copy-number plasmid pME6030 containing ampR.

^fP value of <0.05 compared between PAO1 and PAOampR.

^gP value of <0.05 compared between PAOampR and PAOampR/pSJ06.