Fig 3.

RT-PCR and Western blot analysis of stx₂ expression. stx₂ mRNAs of EDL933 are shown in the first lanes of each panel. Total RNA was extracted from a log-phase culture incubated for 2 h after mitomycin C addition. For each RT-PCR, 300 ng of total RNA was used to make cDNA, which was subsequently amplified by PCR. The expression of stx₂ mRNA was analyzed with stx2-F3 and R3 primer set (see Fig. 1A). 16S rRNA was used as an internal control for total mRNA amount used in each RT-PCR. The presence or absence of Stx2 signal determined by Western blotting are indicated as “+” (“+/−” for basal level production) and “−”, respectively. The experiments were repeated at least three times with similar results.