Starvation-Survival Processes of a Marine Vibrio

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Abstract
Levels of DNA, RNA, protein, ATP, glutathione and radioactivity associated with [35S]methionine-labeled cellular protein were estimated at various times during the starvation-survival process of a marine psychrophilic heterotrophic Vibrio sp., Ant-300. Values for the macromolecules were analyzed in terms of total, viable and respiring cells. EM (thin sections) was done on log-phase and 5.5 wk-starved cells. On a per cell basis, the levels of protein and DNA rapidly decreased until a constant level was attained. A 2nd method in which 35S was used for monitoring protein demonstrated that the cellular protein level decreased for .apprx. 2.5 wk and then remained constant. An initial decrease in the RNA level with starvation was noted, but with time the RNA (orcinol-positive material) level increased to 2.5 times the minimum level. After 6 wk of starvation, 45-60% of the cells remained capable of respiration as determined by iodonitrotetrazolium violet-formazan granule production. Potential respiration and endogenous respiration levels fell, with an intervening 1 wk peak, until at 2 wk no endogenous respiration could be measured; respiratory potential remained high. The cell glutathione level fell during starvation, but when the cells were starved in the presence of the appropriate amino acids, glutathione was resynthesized to its original level, beginning after 1 wk of starvation. The cells used much of their stored products and became ultramicrocells during the 6 wk starvation-survival process. Ant-300 underwent many physiological changes in the 1st wk of starvation that relate to the utilization or production of ATP. After that period, a stable pattern for long-term starvation was demonstrated.