Abstract
The cellular content of glycogen and sucrose in Synechococcus elongatus PCC 7942 was determined using an enzymatic method. The amount of glycogen in the cells was progressively increased in the late growth phase (OD730 > 2). Sucrose serves as an osmoregulatory compound under high salinity environment in certain cyanobacteria and was not detected when Synechococcus cells were grown in a low-salt medium. The synthesis of sucrose was observed in 30 minutes after the addition of 0.2 M NaCl. The intracellular sucrose content attained to a constant level (35 nmol/ml/OD730) in 8 hours. The addition of 0.2 M NaCl abolished the growth of the mutant defective in glycogen accumulation. The sucrose synthesis was observed in the high salt concentration but its rate was slower than in the wild type cells. The result suggested that the polysaccharide accumulated in the cells had the vital role during the growth under high salinity environment.
