Regulation of nucleic acid synthesis in Artemia salina nauplii by environmental salinity.

Ribonucleic acid synthesis in Artemia salina nauplii was strongly inhibited by increasing salinity in the surrounding media, as measured by incorporation of tritiated uridine. Although precursor pools varied in both concentration and specific activity with increasing salinity, these changes did not account for the reduction in ribonucleic acid synthesis. Low levels of oxygen at high salt concentrations did not account for this effect. Intracellular ATP concentrations decreased as the salinity of the environment was increased. Levels of ATP were not affected either by increased oxygen or by the presence of ouabain in the medium.