Fig. 5
β-Lactamase translocation is enhanced in SIEC-eEtgA. A Scheme of β-lactamase (Bla) translocation by the SIEC strain fused to the T3S-signal EspF20. The CCF2 substrate is cleaved by the β-lactamase inside the mammalian cell, switching the emission of green (520 nm) fluorescence to blue (450 nm) fluorescence. On top left, the constructs EspF20-Bla and Bla (lacking T3S-signal) are represented in the pBAD18-derivatives under the l-arabinose-dependent PBAD promoter [43]. B Histogram showing the Bla translocation assay results with different SIEC-derived strains expressing Esp20-Bla, or SIEC (Bla) control without the EspF20 signal. The strains SIECΔp1 and SIECΔp1-eEtgA do not assemble functional injectisomes and are used as negative controls. The results are the means and standard errors of five independent experiments. Statistical analysis was performed using the two-tailed Student’s t test. The asterisk indicates p-value < 0.05