Table 1

Transposition frequencies of pBAM1

Resistance frequency

Analyses of exconjugants


Techniquea

Spontaneousb

Non-spontaneousc

Sampled

Transpositione

Cointegratesf


Mating

Not detectable

1.8 ± 0.53 × 10-3

200

200

0

Electroporation

Not detectable

1.02 ± 0.38 × 10-7

100

100

0


a The pBAM1 plasmid was introduced into recipient cells either by five-hour tri-parental mating or by electroporation, letting the cells to recover after the electro-pulse in LB at 30°C for one hour. Electroporation figures are the average of the frequencies obtained using 100 ng (1.1 ± 0.5 × 10-7) and 500 ng (0.89 ± 0.2 × 10-7) of plasmid DNA.

b Number of P. putida KT2440 colonies that acquire the marker resistance spontaneously, without mating or electroporation.

c Total number of cells that acquired the mini-transposon, as measured by growth in kanamycin normalized to the total 3 × 107 donor cells. The 5 h mating frequency was averaged using a total of 16 independent experiments. Electroporation was referred to a final cell concentration of 6 × 1010 electrocompetent cells and the frequency determined with 6 independent experiments.

d Number of independent colonies that were screened for the presence of the mini-transposon marker (kanamycin) and for the loss of the plasmid backbone marker (ampicillin).

e Number of kanamycin resistant colonies.

f Colonies that are both resistance to kanamycin and ampicillin, meaning co-integration of the pBAM1 plasmid into their genome.

Martínez-García et al. BMC Microbiology 2011 11:38   doi:10.1186/1471-2180-11-38

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