Figure 6. Membrane fluidity increases in the absence of MreB.

(a) Overall membrane fluidity of several cytoskeletal mutant strains was measured as Laurdan GP of logarithmically growing B. subtilis cells. As a positive control, an increase in fluidity (= decrease in Laurdan GP) was established by adding the membrane fluidizer benzyl alcohol (BA; 30 mM) to wild type cells. The diagram depicts the average values and s.d. of three independent measurements. (b) Ratios between chain lengths of the major fatty acids (C17 and C15) and ratios between the iso and anteiso forms of fatty acids are depicted for the different strains (see Supplementary Table 1 for the detailed composition). High C17/C15 or high iso/anteiso ratios indicate a reduced fluidity. The diagram depicts the average values and s.d. of two independent analyses. Strains used: B. subtilis 168 (wild type), 4264 (ΔrsgI), 3481 (ΔmreC), 4277 (ΔmreB, Δmbl, ΔmreBH, ΔrsgI).