Figure 5.

Growth, gene expression, and metabolism of unsaturated fatty acids by S. aureus. A, strain AH1263 was grown to mid-log phase, treated with 30 μm 16:1(9Z), h16:0, or vehicle (DMSO), and the growth of the cultures was monitored. B, qRT-PCR measurement of ohyA mRNA levels in strain AH1263 exposed to the indicated concentrations of fatty acids. The data are representative of four independent cultures. C, qRT-PCR measurement of farE mRNA in strain AH1263 exposed to the indicated concentrations of fatty acids. The calibrator was glyA, and the p values calculated using the Student's t test (GraphPad) are shown in red. The data are graphed as means ± S.E. D, the conversion of [¹⁴C]18:1(9Z) to [¹⁴C]h18:0 by strain JLB2 (ΔohyA)/pPJ490 and its release into the culture media. We used a ΔfakA strain to prevent incorporation of fatty acids into phospholipid and introduced the SaOhyA expression plasmid pPJ490 to amplify product formation. Culture supernatants were sampled at the indicated times and extracted, and [¹⁴C]18:1(9Z) was separated from [¹⁴C]h18:0 by TLC and quantitated using a Typhoon PhosphorImager. The results from two experiments are plotted.