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. 2003 May;71(5):2724–2735. doi: 10.1128/IAI.71.5.2724-2735.2003

FIG. 4.

FIG. 4.

FIG. 4.

(A) Reduction in Δψ after incubation of HeLa cells with Stx1. Δψ was determined by flow cytometry with the reagent JC-1 as described in Materials and Methods. A decrease in Δψ was associated with a shift of reactive cells toward the lower left quadrant at 3 and 4 h after incubation with Stx1. cont., cells treated without Stx1; Stx1, cells treated with Stx1 (10 ng/ml); Bre A + Stx1; cells pretreated for 1 h with brefeldin A (5 μg/ml) followed by treatment with Stx1 (10 ng/ml).(B) Effects of brefeldin A on apoptosis induced by Stx1 in HeLa cells. Cells either were not pretreated or were preincubated with brefeldin A for 1 h before treatment with Stx1 (10 ng/ml) for 4 h (lanes 1 to 4). DNA fragmentation was then analyzed as described in Materials and Methods. Lane 1, 100 ng of brefeldin A/ml; lane 2, 500 ng/ml; lane 3, 5 μg/ml; lane 4, 50 μg/ml; lane 5, 50 μg of brefeldin A/ml without Stx1.