Generation of a restriction minus enteropathogenic Escherichia coli E2348/69 strain that is efficiently transformed with large, low copy plasmids

Table 1 Transformation efficiencies of E2348/69 vs. E2348/69 ΔhsdR

PLASMID	DESCRIPTION	SIZE	ORI	COPY#	TRANSFORMATION EFFICIENCIES^a
					E2348/69^b	E2348/69^c
pJW15	lux reporter	~10 kb	p15A	10–12	2.5 × 10^-11	8.3 × 10^-5
pNLP10	lux reporter	~10 kb	pSC101	~5	0	5.4 × 10^-5
pLAFR1	cosmid cloning vector	21.6	RK2	5–7	3.0 × 10^-9	9.0 × 10^-7

a. Transformation efficiencies are expressed as the (number of transformants/number of viable cells)/ug DNA. All experiments were repeated at least three times, and one representative experiment is shown.
b. Transformation efficiencies observed with plasmid isolated from E. coli K-12.
c. Transformation efficiencies observed with plasmid isolated from E2348/69ΔhsdR.

ISSN: 1471-2180