TABLE 2.

SUMMARY OF RESULTS OBTAINED USING DIFFERENT PORIN EXPRESSION VECTORS

Expression Strain	Plasmid	Promotor*	Plasmid Derivative†	Expression Mode	Generation Time (t 1/2, min)	Cell Density Achieved by pBs/Parental Plasmid!‡	Expression Level Compared to OmpA§
BZB1107	none	none	none	none	54	none	none
	pMY222	PompF	pBR322	constitutive	49	1.0	1.0
	pYG9	PompF	pBs	constitutive	54	1.0	0.5
	pBsOMPF1	PompF	pBs	constitutive	82	0.8	1.52
	pMY150	PompC	pBR322	100 min	110	1.0	∼2.0
	pBsOMPC1	PompC	pBs	100 min	104	1.0	∼2.1
CE1248	None	None	none	none	155	1.0	1.0
	pJP29	Ppho	pACYC184	inducible	84	1.0	2.5–4.0
	pBsPHO1	Ppho	pBs	inducible	73	1.0	2.5–4.0
	pBsPHO2	Ppho	pBs	inducible	103	1.0	2.5–4.0
pop6510	none	none	none	n.d.	n.d.	n.d.	n.d.
	pAC1	Tac	pBR322	inducible	n.d.	1.0	1.0
	pBsLAMB1	Plac	pBs	inducible/constit.	n.d.	3.0	0.2
	pBsLAMB1Q	Plac	pBs	inducible	n.d.	1.2	1.0

^*See Fig. 1.

^†Little or no change of the reported plasmid copy number (pBR322, pACYC184, 20–50 copies/cell; pBs, 200–500 copies/cell) was observed in this study.

^‡+(–) no significant change in attainable cell density comparable to the strain containing the expression plasmid.

^§Estimated by densitometry of Coomassie Blue-stained SDS-PAGE profiles after normalizing to the level of OmpA.