TABLE 3.

Influence of nitrogen sources on OprD production in P. aeruginosa PAO1

Nitrogen source(s)a	Relative amt of OprDb
7 mM (NH4)2SO4	1.0
20 mM glutamate	4.0
20 mM glutamate + 7 mM (NH4)2SO4	0.9
20 mM alanine	4.0
20 mM alanine + 7 mM (NH4)2SO4	2.4
20 mM arginine	3.2
5 mM arginine	2.8
20 mM histidine	2.8
20 mM KNO3	3.0
10 mM asparagine	0.8
10 mM urea	1.4
0.7 mM (NH4)2SO4	1.2

^aAll cultures were grown with 20 mM succinate as the carbon source. 

^bThe amount of OprD protein was estimated by densitometric analysis of SDS-polyacrylamide gels of individual outer membrane preparations by using ImageQuant version 1.1 (Molecular Dynamics). Values were normalized against the amount of the constitutively expressed outer membrane protein OprF present in each preparation. The amount of OprD observed after growth with succinate and ammonium sulfate was defined as 1.0, and the amounts observed with other carbon sources were calculated relative to this value.