FIGURE 5.

Lysis of Dictyostelium discoideum cells exposed to P. aeruginosa culture supernatants. P. aeruginosa culture supernatant in contact with amoebae grown in the wells of 24-well plates. The amoebae were overlain with P. aeruginosa culture supernatants, and images were acquired at 0, 5, and 10 min. The images taken at each time correspond to the same field. (A) D. discoideum cultures overlain with fresh culture medium were used as negative controls. No cell lysis was observed. (B) PAO1 culture supernatants were used as positive controls (Cosson et al., 2002). A large number of D. discoideum cells were already lysed after 5 min. (C) Example of an isolate (Chir D-144) that was unable to lyse amoebae. (D) Example of an isolate (PPF 13) that caused marked cell lysis. Dead cells left a dark spot (arrow).