TABLE 2.

Effect of plasmid on electrotransformation efficiency of B. fragilis calculated from the results of three independent experimentsa

PlasmidbSelection markerSize (kb)Log10 no. of transformants/μg plasmid DNAc
NCTC9343YCH46
pLYL05Cfxr7.554.28 ± 0.134.01 ± 0.59
pNLY1Cmr7.763.34 ± 0.611.22 ± 0.53
pVAL-1Emr110.05 ± 0.091.66 ± 0.37
pVAL-2Cfxr10.11.27 ± 1.102.83 ± 0.15
  • a B. fragilis cells at mid-exponential growth phase were electroporated with 1.0 μg DNA of each plasmid indicated. After 12 h of postpulse incubation, cells were spread onto GAM agar plates containing the selective antibiotic corresponding to the plasmid used.

  • b All plasmids were purified from E. coli laboratory strain HB101.

  • c The data are means ± standard deviations.