Figure 1. Nitrogen limitation induces glycogen storage in WT and glgC2.

(A–B) Glycogen in WT, mutant and complemented strains was quantified after growth on high (A) or low (B) nitrogen M9-glucose agar by enzymatic hydrolysis of glycogen into glucose monomers. Liberated glucose was subsequently measured using the tetrazolium blue reducing sugar assay and expressed as μg reducing equivalents in 10⁹ V. cholerae/mL. The median and interquartile range of two independent experiments each performed in triplicate are shown. The glgX strain accumulated significantly more glycogen than WT by a two-tailed student’s t-test (*p<0.005). The cross symbol indicates the amount of glycogen was below the limit of detection.