Table 2

Gene replacements in the tir-cesT-eae region of enterohemorrhagic E. coli 0157:H7 using long homology-containing substrates

Exp #
Substrate preparation
Amount of DNA
Genotype of linear fragment
Total Transformants
Percent transformants Amp sensitive
Recombinants verified by PCR (# verified/# tested)

Plasmid digests:
1.
restriction digest pKM184 (SacI, SphI)
2 μg
Δeae::cat
>500
11% (4/35)
1/1
2.
restriction digest pKM185 (SacI, SphI)
2 μg
Δeae-cesT-tir::cat
103
2.6% (2/76)
1/1
3.
restriction digest pKM 187 (SacI, SphI)
1 μg
Δeae::cat sacB
> 500
2.8% (1/35)
1/1
Plasmid digests including backbone:
4.
restriction digest pKM184 (SacI, SphI, ApaLI)
0.5 μg
Δeae::cat
52
57% (4/7)
NT
5.
restriction digest pKM184 (SacI, SphI, ApaLI)
10 μg
Δeae::cat
> 500
95% (143/151)
10/10
6.
restriction digest pKM185 (SacI, SphI, ApaLI)
2 μg
Δeae-cesT-tir::cat
30
56% (9/16)
9/10
7.
restriction digest pKM185 (SacI, SphI, ApaLI)
2 μg
Δeae-cesT-tir::cat
36
50% (9/18)
7/9
Gel-purified fragments:
8.
purified SacI-SphI fragment from pKM185
0.5 μg
Δeae-cesT-tir::cat
225
100% (20/20)
1/1
9.
purified KpnI fragment from pKC2
0.1 μg
Δtir::cat
6
NT
6/6
10.
purified SacI-SphI fragment from pKM188
0.6 μg
Δeae cesT tir::cat sacB
273
100% (40/40)
1/1
11.
purified KpnI fragment from pKC3
0.05 μg
Δtir::cat sacB
2
NT
2/2

Murphy and Campellone BMC Molecular Biology 2003 4:11   doi:10.1186/1471-2199-4-11