Table 2

Effect of high copy plasmid clones on survival following treatment with norfloxacin

Plasmid

Survival Ratio


pCRII vector

2.14 × 10-5 ± 4.1 × 10-6


pAQ5

7.57 × 10-4 ± 2.14 × 10-4


pInter

6.12 × 10-4 ± 1.28 × 10-4


pInterD1

8.41 × 10-5 ± 3.55 × 10-5


pInterD2

1.11 × 10-4 ± 2.01 × 10-5


E. coli BW27784 transformed with high copy number plasmid was grown to exponential phase with shaking. Cultures were treated with 250 ng/ml norfloxacin for 2 h before serial dilution and plating on LB plates with kanamycin

Survival ratio was determined by calculating the ratio of the viable colony counts obtained from the treated cultures versus the viable counts from untreated culture. The results represent the average and standard errors from at least three experiments

Liu et al. BMC Microbiology 2011 11:261   doi:10.1186/1471-2180-11-261

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