TABLE 3.

Transformation frequencies of wild-type strains 1061 and 26695 and HP1527 mutants with chromosomal DNA and plasmid pHEL2

Strain	Transformation frequencya (% of parent frequency) with:
	Chromosomal DNA (Clar) by natural transformationb	pHEL2 (Camr)
1061 (parent)	3 × 10−6 (100)	10−6 (100)
1061, SACHA-1	<10−9 (<0.1)	<10−9 (<0.1)
1061, SACHA-2	<10−9 (<0.1)	<10−9 (<0.1)
26695 (parent)	10−6 (100)	n.d.c
26695, SACHA-1	<10−9 (<0.1)	n.d.

^aDetermined as the number of resistant colonies per microgram of DNA per recipient CFU. Data represent the means of two experiments. 

^bElectroporation was successful for each strain. 

^cn.d., not determined.