Table 1

Plasmid supercoiling measurements from relaxation experiments

Genotype

Experimental treatment

Plasmid σ

Model ratio

gyrA^RparC^R

15 μg/ml Nor, 0 min

-0.057

1.0

gyrA^RparC^R

15 μg/ml Nor, 2 min

-0.057

1.0

gyrA^RparC^R

15 μg/ml Nor, 5 min

-0.057

1.0

gyrA^RparC^R

15 μg/ml Nor, 10 min

-0.057

1.0

gyrA^RparC^R

15 μg/ml Nor, 20 min

-0.060

1.0

gyrA^RparC^R

15 μg/ml Nor, 30 min

-0.060

0.9

gyrA^RparC^R

50 μg/ml Nor, 0 min

-0.057

1.0

gyrA^RparC^R

50 μg/ml Nor, 2 min

-0.057

1.0

gyrA^RparC^R

50 μg/ml Nor, 5 min

-0.057

1.0

gyrA^RparC^R

50 μg/ml Nor, 10 min

-0.058

1.0

gyrA^RparC^R

50 μg/ml Nor, 20 min

-0.059

1.0

gyrA^RparC^R

50 μg/ml Nor, 30 min

-0.061

0.9

gyrB⁺

37°C

-0.059

1.0

gyrB⁺

42°C, 2 min

-0.059

1.0

gyrB⁺

42°C, 5 min

-0.059

1.0

gyrB⁺

42°C, 10 min

-0.059

1.0

gyrB⁺

42°C, 20 min

-0.061

1.0

gyrB^TS

37°C

-0.044

1.0

gyrB^TS

42°C, 2 min

-0.023

1.6

gyrB^TS

42°C, 5 min

-0.016

1.8

gyrB^TS

42°C, 10 min

ND

ND

gyrB^TS

42°C, 20 min

0.000

2.5

gyrA⁺parC^R

15 μg/ml Nor, 0 min

-0.057

1.0

gyrA⁺parC^R

15 μg/ml Nor, 2 min

-0.025

1.7

gyrA⁺parC^R

15 μg/ml Nor, 5 min

-0.009

2.2

gyrA⁺parC^R

15 μg/ml Nor, 10 min

-0.006

2.3

gyrA⁺parC^R

15 μg/ml Nor, 20 min

-0.002

2.4

gyrA⁺parC^R

15 μg/ml Nor, 30 min

0.000

2.5

gyrA⁺parC⁺

50 μg/ml Nor, 0 min

-0.057

1.0

gyrA⁺parC⁺

50 μg/ml Nor, 2 min

-0.016

1.9

gyrA⁺parC⁺

50 μg/ml Nor, 5 min

-0.002

2.4

gyrA⁺parC⁺

50 μg/ml Nor, 10 min

0.000

2.5

gyrA⁺parC⁺

50 μg/ml Nor, 20 min

0.007

2.8

gyrA⁺parC⁺

50 μg/ml Nor, 30 min

0.016

3.2

gyrA⁺parC⁺

15 μg/ml Nor, 0 min

-0.055

1.0

gyrA⁺parC⁺

15 μg/ml Nor, 10 sec

-0.048

1.1

gyrA⁺parC⁺

15 μg/ml Nor, 25 sec

-0.040

1.3

gyrA⁺parC⁺

15 μg/ml Nor, 45 sec

-0.032

1.5

gyrA⁺parC⁺

15 μg/ml Nor, 1 min

-0.027

1.6

gyrA⁺parC⁺

15 μg/ml Nor, 1.5 min

-0.022

1.7

gyrA⁺parC⁺

15 μg/ml Nor, 2 min

-0.017

1.9

gyrA⁺parC⁺

15 μg/ml Nor, 3 min

-0.012

2.1

gyrA⁺parC⁺

15 μg/ml Nor, 4 min

-0.008

2.2

gyrA⁺parC⁺

15 μg/ml Nor, 5 min

-0.003

2.4

gyrA⁺parC⁺

15 μg/ml Nor, 7 min

0.000

2.5

gyrA⁺parC⁺

15 μg/ml Nor, 10 min

0.003

2.6

gyrA⁺parC⁺

15 μg/ml Nor, 15 min

0.002

2.6

gyrA⁺parC⁺

15 μg/ml Nor, 20 min

0.000

2.5

ΔacrA

0 μg/ml Novo, 0 min

-0.057

1.0

ΔacrA

20 μg/ml Novo, 5 min

-0.011

2.1

ΔacrA

50 μg/ml Novo, 5 min

0.005

2.7

ΔacrA

200 μg/ml Novo, 5 min

0.011

3.0

pBR322 plasmid DNA was isolated from cells and analyzed by electrophoresis. Experimental treatments in bold indicate samples taken immediately before addition of drug or temperature shift, which were used as a reference for the following time points. Model ratios represent values derived from plasmid σ by taking the ratio of σ in each time point and dividing by σ in the reference, and scaling that value such that a sigma of 0 corresponds to a model ratio of 2.5. Nor, norfloxacin; Novo, novobiocin; SSG, supercoiling-sensitive gene; TS, temperature-sensitive. ND, not determined.

Peter et al. Genome Biology 2004 5:R87   doi:10.1186/gb-2004-5-11-r87