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Table 2 Specific yield, plasmid copy number, and repA expression from cultures of DH5α[pDMB-ATG] with and without a temperature shift

From: Development of new plasmid DNA vaccine vectors with R1-based replicons

Temperature Time (hr)a Specific yield (mg pDNA/g DCW) Plasmid copies/chromosome repA expressionc repA expression/plasmidd
30°C 0 NDb 13 ± 3 0.09 ± 0.01 0.30 ± 0.09
  2 0.2 ± 0.1 20 ± 4 0.06 ± 0.00 0.13 ± 0.03
  4 1.0 ± 0.0 54 ± 1 0.20 ± 0.02 0.15 ± 0.02
  8 2.3 ± 0.3 96 ± 27 0.32 ± 0.02 0.14 ± 0.04
42°C 2 1.9 ± 0.1 243 ± 32 1.00 ± 0.08 0.17 ± 0.03
  4 5.1 ± 1.9 407 ± 210 15.20 ± 1.13 1.56 ± 0.83
  8 11.4 ± 1.7 476 ± 176 9.85 ± 0.64 0.86 ± 0.34
  1. Error bars represent the standard deviation of duplicate samples.
  2. aTime after temperature shift.
  3. bNot detected (below detection limit of HPLC assay).
  4. cNormalized to repA expression from pDMB02-GFP at t = 0 in flask replicate 1 (Table 1).
  5. drepA expression multiplied by a factor of (t = 0 pDMB02-GFP copy number)/(plasmid copy number of sample) to give an estimate of relative repA expression per plasmid.