Figure 3.
Complementation of AI-2 production in S. typhimurium CS132 and E. coli DH5α. Cell-free culture fluids from E. coli and S. typhimurium strains were tested for AI-2 activity in the bioassay. The activity present in these fluids was compared with that produced by wild-type V. harveyi BB120. The level of BB120 activity was normalized to 100%. (A) AI-2 activity in cell-free fluids from wild-type V. harveyi BB120, E. coli O157:H7, and S. typhimurium LT2. (B) Complementation of S. typhimurium CS132 (ygaG∷MudJ). (C) Complementation of E. coli DH5α. In B and C, the in trans AI-2 production genes are the following: vector control (“none”), E. coli O157:H7 ygaG, and V. harveyi BB120 luxSV.h.. E.c., E. coli; V.h., V. harveyi.