TABLE 1.

Electrotransformation of E. coli JM109 with concentrated extracellular DNA from 0.25 ml of cocultured E. coli LE392(pKZ105)

Culture condi- tion of E. coli LE392(pKZ105)Cultivation period (no. of days)No. of transformants (CFU) (mean ± SD)
ExpectedaDetected
Cocultured with E. gracilis300
7(5.7 ± 2.7) × 101(1.0 ± 0.5) × 100
10(2.7 ± 0.5) × 102(4.0 ± 2.0) × 100
17(1.2 ± 0.2) × 1030
Cocultured with C. neglecta3(2.1 ± 0.2) × 1020
7(1.9 ± 0.9) × 1020
10(1.0 ± 0.5) × 1020
17(1.2 ± 0.3) × 1020
Cocultured with C. inversa3(2.6 ± 0.2) × 101(2.8 ± 1.3) × 101
7(2.7 ± 0.8) × 1010
10(1.6 ± 0.1) × 1010
17(1.8 ± 0.1) × 1010
Cocultured with M. aeruginosa3(2.7 ± 1.7) × 101(1.0 ± 0.5) × 100
700
1000
1700
  • a Expected numbers of transformants were calculated from the equation of linear regression of the standard curve, using the amount of pKZ105 detected from each coculture.