Figure 3. ΔopuA-D mutant strain produces excess trehalose.

Bacteria were grown in M9 with 0.01 M NaCl or 0.4 M NaCl. A) Sugars were extracted from equal numbers of bacteria and analyzed by thin-layer chromatography (TLC). Sugar standards, lanes 1–7, arabinose (10μg), galactose (10 μg), sucrose (10 μg), maltose (10 μg), glycerol (80μg), trehalose (20 μg), glucose (10 μg), respectively. Lanes 8–15 as noted. B) Integrated densitometric analysis of four TLCs was performed using Image J software. Arbitrary values correspond to the product of the area and mean grey values, 0.4 M NaCl (black) or 0.01 M NaCl (white). Error bars are SEM. C) Total glucose accumulation (mg/mL) quantified by the glucose-hexokinase conversion assay. Strains as noted were grown in M9 in 0.4 M NaCl (black) or 0.01 M NaCl (white). Error bars are SEM, N > 3 experiments. D) Trehalose accumulated (ng per 1x10⁶ bacteria) quantified as described in the Experimental Procedure from bacteria grown in M9 with 0.4 M NaCl. Error bars are SEM, N > 3 experiments. ns, not significant. Asterisks indicate P < 0.05 (*) and 0.01 (**).