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. 2013 Nov 22;5(11):2270–2280. doi: 10.3390/toxins5112270

Figure 3.

Figure 3

Analysis of CNF1 secretion into HBMEC monolayer. Translocation of CNF1-Bla into HBMEC induces catalytic cleavage of the CCF4 β-lactam ring, which produces an easily detectable color change in CCF4 fluorescence from green to blue emission. In the parent strain RS218/pCXN, CNF1-Bla was, as expected, successfully translocated into HBMEC, as shown by the emission of blue fluorescence. In contrast, Δfdx and ΔygfZ mutants harboring pCXN showed no blue emission, indicating no translocation of CNF1 into HBMEC. Of note, CΔfdx and YK7 represent the complemented strains of Δfdx and ΔygfZ mutants with wild type fdx and ygfZ, respectively, which showed predominant blue emission, indicating the translocation of CNF1 into HBMEC (modified from [40,41]).