FIG. 6.
Changes in apoptotic markers after incubation with Pseudomonas HSLs. (a) U-937 cells were incubated with or without 50 μM C4-HSL or 3-oxo-C12-HSL for 4 h. Cell lysates were then collected and examined for caspase 3 and 8 activities and levels of histone-associated DNA fragments (n = 5 to 6). *, P < 0.05 compared with the nontreated control group. (b) U-937 cells were treated with or without 50 μM C4-HSL or 3-oxo-C12-HSL for 4 h, and then expression of annexin V-fluorescein isothiocyanate and propidium iodide was examined as described in Materials and Methods.