The kinetics of ribonucleic acid- and protein formation in Salmonella typhimurium during the transition between different states of balanced growth

Abstract

1. 1. During an experiment, in which bacteria are transferred from a glucoseammonia-salts medium into broth at 37° (shift up) the rate of ribonucleic acid synthesis in Salmonella typhimurium is greatly increased for the first 30 min. After this period the rate settles at the value characteristic of the broth medium. 2. 2. It is suggested that the diphasic shape of the curve for ribonucleic acid formation is due chiefly to an accelerated synthesis of ribosomal particles. 3. 3. Under steady state conditions of growth a constant relationship is observed between the cell content of ribosomes and the rate of protein synthesis. 4. 4. In a “shift up” experiment, the rate of protein synthesis is initially low, but reaches the rate characteristic of the broth medium about 20 min after the change in growth medium. 5. 5. The data for protein synthesis agree well with the suggested course of ribosome formation and the proportionality constant between ribosome content and rate of protein synthesis observed under steady state conditions.