A critical examination of the role of de novo protein synthesis in the osmotic adaptation of the halotolerant alga Dunaliella

The role of protein synthesis during the osmotic adaptation of Dunaliella salina was examined utilizing protein synthesis inhibitors. 3–4 h of preincubation with cycloheximide or chloramphenicol were required to observe full inhibition of protein synthesis. Algae treated with cycloheximide, chloramphenicol or both reagents prior to a hyper‐ or hypo‐osmotic shock showed no significant difference in their osmotic response when compared to untreated controls. Thus, protein synthesis is not essential for the osmotic adaptation response. Cell division was halted following a hyper—osmotic shock, but proliferation was reinitiated already during the late phase of the osmotic response and exponential growth was resumed soon after completion of the osmotic response.