TABLE 1.

Interspecies and intraspecies conjugational recombination in bacterial crosses and analysis of SOS induction in E. coli recipient exconjugant cells

E. coli F− recipient	Salmonella serovar Typhimurium Hfr strain SA977 (mean ± SD)a		E. coli PK3 (mean ± SD)
	Recombinationb	SOS inductionc	Recombination	SOS induction
MT1	2.20 × 10−6 ± 6.06 × 10−7	0.023 ± 0.016	2.99 × 10−1 ± 2.77 × 10−1	<0.0001
MT1 lexA1	1.28 × 10−7 ± 3.08 × 10−8	<0.0001	6.65 × 10−2 ± 4.42 × 10−2	<0.0001
MT1 lexA1 recAo98	1.47 × 10−5 ± 5.57 × 10−6	0.019 ± 0.008	7.80 × 10−2 ± 2.16 × 10−2	<0.0001
MT1 mutS	5.00 × 10−3 ± 1.59 × 10−3	0.015 ± 0.006d	1.01 × 10−1 ± 6.50 × 10−2	<0.0001
MT1 mutS lexA1	6.43 × 10−5 ± 3.78 × 10−5	<0.0001	2.36 × 10−2 ± 1.60 × 10−2	<0.0001
MT1 mutS lexA1 recAo98	2.20 × 10−3 ± 9.76 × 10−4	0.017 ± 0.012	7.20 × 10−2 ± 7.21 × 10−3	<0.0001
MT5	4.33 × 10−6 ± 1.67 × 10−6	<0.0001	6.90 × 10−1 ± 1.73 × 10−1	<0.0001

^aEach number represents the results of three to six independent experiments. 

^bNumber of Ilv⁺ recombinants per number of Hfr cells (equal to number of Ilv⁺ recombinants per number of F⁻ cells; the ratio of Hfr cells to F⁻ cells was 1:1), after 30 min of conjugation. The recombinants were selected on M63 minimal medium selective plates and scored after 48 h at 37°C. 

^cNumber of Gal⁺ F⁻ cells per total number of F⁻ cells, after 30 min of conjugation. Gal⁺ colonies on MacConkey agar-galactose plates were scored after 24 h at 37°C. 

^dThese SOS-induced (Gal⁺) and noninduced (Gal⁻) colonies were analyzed for their Ilv⁺ recombination frequencies.