Figure 6

Expression of plasmid-borne transcriptional fusions to P _tauA in C. crescentus NA1000. (A) NA1000 carrying P _tauA -uidA reporter plasmids, without or with tauR (pJC478 or pJC479, respectively), were grown for two hours in PYE rich medium without or with 10mM taurine and assayed for GUS activity. (B) NA1000 carrying pJC479 was induced for two hours with increasing concentrations of taurine in PYE. Wild-type strains carrying plasmids without the uidA gene (pJC472 or pJC473) exhibited negligible levels of GUS activity (<0.1 Miller units; data not shown). (C, D) P _tauA -mCherry expression level depends on taurine concentration in (C) PYE rich medium or (D) M2G defined medium. NA1000 carrying pJC503 was induced for four hours with increasing concentrations of taurine and assayed for fluorescence. Fluorescence values were adjusted by subtracting the background fluorescence of a strain carrying the vector pRVMCS-5. Error bars represent standard errors of the mean of at least six independent measurements.