FIGURE 4.

Response of wild-type and fabR-null strains to the inhibition of lipid A synthesis with CHIR-090. Strains were pulsed with [¹⁴C]acetate for 10 min prior to CHIR-090 treatment to establish the normal UFA:SFA ratio in the fatty acid produced by this strain. Next, CHIR-090 was added, and samples were removed at 0, 10, 20, 30, and 40 min and pulsed with [¹⁴C]acetate for 10 min, and the UFA:SFA ratio was determined following the preparation of methyl esters, separation by argentation thin layer chromatography, and quantification of the ratio of labeled UFA and SFA as described under “Experimental Procedures.” A, strain UB1005. B, strain KZ6 (ΔfabR). C, increased fabB gene expression following a 10-min treatment with CHIR-090. The levels of fabB expression was determined by quantitative reverse transcription-PCR before and after CHIR-090 treatment as described under “Experimental Procedures.” Transcript levels were normalized to acpP, and the level of fabB mRNA in the wild-type, untreated strain was set as 1.0 to calculate the comparisons. The mean of triplicate experiments ± S.E. is plotted.