Virulence towards Dictyostelium discoideum. Approximately 100 D. discoideum cells were cultivated in SM-plates with the indicated proportion of Klebsiella aerogenes and Pseudomonas strains (10%). Plates were maintained at 22°C for 5 days. A: Pseudomonas aeruginosa PA14 (positive control), Klebsiella aerogenes (KA, negative control) and P. fluorescens MFN1032 virulence towards D. discoideum after 5 days. B: Virulence of different Pseudomonas strains at 10% against D. discoideum. These results were obtained by the ratio of the number of lysis plaques obtained with the negative control Klebsiella aerogenes (100% of amoebae remained). Standard deviation is shown. Data are mean values from three independent experiments. C: D. discoideum growth on layer of MFN1032, MFN1030 or KA as described in the materials and methods. 1000, 100, 10 and 1 indicated number of D. discoideum per μL.