Fig. 4.

P. aeruginosa is capable of natural transformation of plasmid DNA in static broth cultures. Carbenicillin-resistant transformants obtained from static broth cultures incubated at 37 °C for 24 h with (a) 10 µg pUCPSK or (b) 0.1–30 µg pUCPSK with PAK (circles) or PAO1 (squares). The mean of each set of technical triplicates was calculated to give an n≥3, which is presented as mean±sem. For (a) ** P<0.005; Mann–Whitney U-test compared to PAK. For (b) there was no significant difference (P>0.05; Friedman with Dunn’s multiple comparisons test) between DNA concentrations (0.1–30 µg) for both strains.