FIG 5.

S-CDT-mediated DNA damage primarily occurs in the S and G₂/M phases of the cell cycle of HIEC-6 human intestinal epithelial cells. HIEC-6 cells infected with S. Javiana wild-type (WT) and ΔcdtB strains for 48 h were stained to detect γH2AX and DNA content to determine the specific phases of the cell cycle during which S-CDT-mediated DNA damage occurred. (A) Representative histograms of DNA cell cycle analysis of HIEC-6 cells (gray) with γH2AX-positive cells overlaid (blue). (B) Quantification of γH2AX-positive HIEC-6 cells by cell cycle phase. Results are from two independent experiments. Treatments that do not share letters represent significantly different mean proportions (P < 0.05) of cells positive for a given cell cycle phase (e.g., proportions of γH2AX-positive cells in G₁ were compared for the four treatment groups). P values were corrected for multiple comparisons using Tukey’s HSD test. Error bars represent standard errors of the means.