Figure 1

Construction and screening of ironQS systems. (A) Plasmid diagram of a basal cell density regulated expression plasmid pQS. P _luxI , the promoter of luxI gene; P _luxR , the promoter of luxR gene; TT, transcription terminator; RBS, ribosome binding site; katushka, a reporter gene which product generates red fluorescence. (B) Linear structure illustrations of four quorum sensing-based in vivo expression systems ironQS1-4. (C) Relative fluorescence values of E. tarda strains containing ironQS1-4 after cultured in iron-rich and iron-limited media respectively. E. tarda loaded with pQS and blank strain were set as controls. * means a significant deviation.