CHANGES IN RNA AND PROTEIN-SYNTHESIS ASSOCIATED WITH THE ADAPTATION OF SYNECHOCOCCUS SP TO 0.4-M NACL

The effect of 0.4 M NaCl on protein and RNA synthesis in the cyanobacterium Synechococcus was studied. The rate of [C-14]leucine and [H-3]uridine incorporation over 3 hr was measured by TCA precipitation of protein and RNA molecules present in sonicated extracts of control, salt-grown and osmotically shocked cells. Protein and RNA syntheses rates were markedly higher in salt-adapted cells. Hyper-osmotic shock (resuspension of control cells in 0.4 M NaCl) elicited a stimulation in protein synthesis while RNA synthesis was initially depressed when compared to control cells. Hypo-osmotic shock (resuspension of salt-grown cells in basal media) initially depressed both rates relative to salt-adapted cells. It is concluded that adaptation to 0.4 M NaCl in this organism is correlated with rapid (1-3 hr) and substantial changes in the rates of transcription and translation.