FIG. 4.

Adaptation of B. subtilis JH642 to cold shock in minimal medium supplemented with different precursors of branched-chain fatty acid biosynthesis. The cold-protective effect of precursors for different branched-chain fatty acids was tested by performing cold shock experiments as described in Materials and Methods. The substrates for fatty acid synthesis were added to a final concentration of 100 μM 5 min prior to chilling. Cellular adaptation was measured by determining cell density at 600 nm. ■, 100 μM isoleucine; ●, 100 μM α-keto-β-methyl-valerate; ▴, 100 μM 2-methyl-butyrate; ▾, 100 μM α-keto-iso-caproate; ⧫, 100 μM α-keto-iso-valerate; □, no addition.