The Regulation of RNA Synthesis during Growth Rate Transitions and Amino Acid Deprivation in E. coli

The composition of bacterial cells shows a regular variation with growth rate, irrespective of the chemical composition of the medium (Schaechter, Maaløe, and Kjeldgaard, 1958; Neidhardt and Magasanik, 1960). Cells cultured in rich media contain more RNA per genome equivalent of DNA than cells from media supporting a slow rate of growth. Calculations based on the cell composition and growth rate indicate that the average rate of protein synthesis per ribosome does not vary with growth rate or ribosome content of the cell (Schaechter, Maaløe, and Kjeldgaard, 1958). These results indicate that the synthesis of ribosomal RNA (rRNA) is well coordinated with the cell's capacity for protein synthesis.