Cells of Arthrobacter atrocyaneus and A. crystallopoietes, harvested during their exponential phase, were starved in 0.03 M
phosphate buffer (pH 7.0) for 28 days. During this time, the cells maintained 90 to 100% viability. Experimental results were similar for both organisms. Total cellular
deoxyribonucleic acid was maintained. Measurable degradation rates for
deoxyribonucleic acid as determined by
radioisotope techniques were not observed, and only during the initial hours of
starvation could a synthetic rate be determined. Total
ribonucleic acid levels remained stable for the first 24 h of
starvation, after which slow, continuous loss of
orcinol-reactive material occurred. Synthetic and degradative rates of
ribonucleic acid, as determined by
radioisotope techniques, dropped quickly at the onset of
starvation. Constant basal rates were attained after 24 h. In A. atrocyaneus, total cell
protein was degraded continuously from the onset of
starvation. In A. crystallopoietes, total cell
protein remained stable for the first 24 h, after which slow continuous loss occurred. After 28 days, the total
protein per cell was similar for both organisms. In the first week,
amino acid pools stabilized at about 50% of the values characteristic of growth. Rates of degradation of
protein decreased rapidly for the first 24 h for both organisms, but leveled to a constant basal rate thereafter. Rates of new
protein synthesis dropped during the first 24 h and by 48 h achieved a constant basal rate.