INTERACTION OF SALINITY AND TEMPERATURE ON NET PROTEIN SYNTHESIS AND VIABILITY OF VIBRIO MARINUS1,2

The relationship of temperature and salinity to protein synthesis was determined for cells of Vibrio marinus. The critical temperature of the lesion in protein synthesis increased with increasing salinity of the growth medium. Protein synthesis was significantly inhibited at 22C at a salinity of 25‰, but not at a salinity of 35‰ until the cells were incubated for 20 min at 24C. The thermal lesion did not involve precursor accumulation mechanisms rather than protein synthesis at salinities between 25 and 35%. At 40‰, the uptake of extracellular proline by whole cells was inhibited at 24C and preceded the inhibition of precursor into protein. Total RNA synthesis continued for 50 min at 22C in growth media at salinities between 15 and 35‰ but at 40‰ decreased after 20 min of cell incubation. At salinities between 15‰ and 30‰, total RNA synthesis continued at 15 and 22C, but cellular protein synthesis was inhibited by either temperature or salinity effects. Loss of cell viability at 22 and 25C at salinities of 25 and 35‰ showed that the onset of cell death occurs simultaneously with thermal inhibition of protein synthesis.