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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.
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BMC Biotechnology

ISSN: 1472-6750

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