ALTERATIONS OF PROTEIN-SYNTHESIS IN THE CYANOBACTERIUM SYNECHOCYSTIS SP PCC-6803 AFTER A SALT SHOCK

Salt-induced changes in protein synthesis were investigated in the cyanobacterium Synechocystis sp. PCC 6803. Immediately after a salt shock of 684 mM-NaCl, total protein synthesis was almost completely blocked. Then, parallel to the accumulation of the osmoprotective compound glucosylglycerol, protein synthesis recovered gradually but remained diminished. The activation of glucosylglycerol synthesis was not inhibited by chloramphenicol at concentrations which totally inhibited protein synthesis. The qualitative protein composition of salt-shocked and control cells was similar. However, the rates of synthesis of single proteins were altered in cells shocked for 10 h and adapted to high salt conditions. Using two-dimensional gel electrophoresis, proteins were found which were synthesized at enhanced rates after adding salt.