FIG 6.

Transcriptional levels of leuO under various concentrations of cFP and transcriptional levels of vhuA and vhuB modulated by LeuO differentially expressed in the arabinose induction system. (A) Transcription levels of LeuO as measured by β-galactosidase activities of V. vulnificus MO6-24/O harboring pMZtc-leuO cultured in AB broth and treated with 0 mM, 1 mM, or 5 mM cFP. (B) Transcription levels of vhuA (left) and vhuB (right) as measured by β-galactosidase activities from MO6-24/O(pBBR1-MCS2) harboring pMZtc-vhuA or pMZtc-vhuB and from ΔleuO(pBBR12-leuO-ara) harboring pMZtc-vhuA or pMZtc-vhuB cultured in AB broth. The culture conditions are described in Materials and Methods. To induce the expression of LeuO by arabinose, the culture was split into seven aliquots when the A₆₀₀ reached 0.1, and then various concentrations of arabinose (0, 0.005, 0.01, 0.05, 0.1, 0.5, and 1%) were added. The error bars denote standard deviations of the results of three independent experiments. MU, Miller units.