Skip to main content

Table 1 Properties of pFab and pUC19

From: Plasmid selection in Escherichia coli using an endogenous essential gene marker

Parametersa pUC19 pFab
Transformation efficiencyb (CFU/μg) 5.5 × 107 ± 1.2 × 107 2.2 × 107 ± 3.6 × 106
Plasmid yieldc (μg/ml) 30 ± 2.1 42.9 ± 3.5
Copy numberd 141 ± 25 200 ± 33
Stability (%)   
   With selectione 85.3 ± 10.8 99.5 ± 1.5
   Without selectionf 56.7 ± 17.7 54.5 ± 14.9
Relative growth rateg (ΔOD/Δt)   
   With selection 1 1.2 ± 0.07
   Without selection 1.1 ± 0.05 0.6 ± 0.02
  1. a Determined from five replicate cultures.
  2. b In chemically competent DH5α cells.
  3. c Plasmid yield from 1 ml of 18 h culture, determined by OD260 absorbance.
  4. d Determined from the copy ratio of lacZα to dxs by qPCR.
  5. e Percentage of plasmid-bearing cells at 48 h in cultures grown with selection.
  6. f Percentage of plasmid-bearing cells at 48 h in cultures grown without selection.
  7. g Change in OD550 over time of DH5α/pUC19 cultures in LB and DH5α/pFab in LB or LBT, relative to control DH5α/pUC19 cultures in LBA.