Fig 6.

Genotoxic effect of PaCDT. CHO cells were treated with filter-sterilized lysates of bacteria producing EcCDT-I (GB1371) or PaCDT (AH-31). After 16 h of treatment, the cells were stained as described in Materials and Methods with Alexa Fluor 546-conjugated phalloidin (upper panels) or with fluorescein isothiocyanate-conjugated anti-phospho-histone H2AX (H2AX) monoclonal antibody (middle panels). EcCDT-I- and PaCDT-treated cells exhibited nuclear H2AX indicating host DNA double-strand breaks, enlarged nuclei and cell bodies, and the absence of mitotic features. Filter-sterilized lysate of E. coli C600 was used as a negative control. The experiment was repeated at least three times.