Table 1.

Expression of a prpL-lacZ fusion

Strain	β-Galactosidase activity (EU)*
	−Pyoverdine	+Pyoverdine
PAO1 (pPZ-prpL)	8.6 (100)	9.4 (109)
PAO1 pvdF (pPZ-prpL)	1.9 (22)	9.8 (113)

Values are the average of at least three different experiments; SDs were less than 12% in each case. Values in parentheses are the % of that obtained with PAO1 without added pyoverdine. 

^*The amounts of β-galactosidase made by strains PAO1 and PAO1pvdF containing plasmid pPZ-prpL were assayed. EU, β-galactosidase enzyme units.