Effect of treY, treZ, treY/treZ, galU, galU/treY, and galU/treYZ expression on the intracellular content of glycogen (A) and trehalose (B), in the late exponential growth phase in C. glutamicum strains, under IPTG induction (░⃞) and in uninduced states (□). Each uptake value represents the mean for three different uptake experiments ± the standard error.