Figure 6
Effect of zinc and other metals on expression of LEE operons as measured in reporter strains. Reporter strains JLM165 (for LEE4, encoding the Esps) KMTIR3 (for LEE5, encoding Tir and intimin) and mCAMP (for beta-lactamase) were used to measure gene expression using the Miller assay. Panels A and B, expression of LEE4 and LEE5 were significantly increased in dose-dependent fashion by hypoxanthine in the presence of XO, compared to without added XO. Panel C, LEE5 expression was modestly but significantly increased in response to H2O2. Panel D, zinc acetate, but not MnCl2, inhibited induced LEE4 expression. *significant compared to “plus cipro, no-metal” condition. Panel E, lack of effect of zinc on expression of beta-lactamase in the bla-lacZ reporter strain in two different types of liquid media, minimal medium (MM) and DMEM.