Role of Protein Synthesis in the Cell Division and Starvation Induced Resistance to Autolysis of a Marine Vibrio during the Initial Phase of Starvation

Abstract

Starvation of a marine Vibrio sp. S14 for carbon, nitrogen and phosphorus resulted in a fourfold increase in cell number during the first 6 h in the starvation regime. This initial cell division of non-growing cells was dependent on both DNA and peptidoglycan synthesis as deduced from inhibition experiments using nalidixic acid and ampicillin. Inhibition of protein synthesis by the addition of chloramphenicol led to the cessation of both cell division and DNA synthesis after 40–60 min in the starvation regime. Starvation also induced resistance against autolytic cell wall degradation. Resistance to ampicillin-induced murein degradation was most extensive in the portion of the cell wall that was synthesized after the onset of starvation and was dependent on de novo protein synthesis. The amount of d-alanine per unit dry weight increased twofold during 24 h of starvation and an increased resistance to lysis induced by sonication was observed during this period. It is suggested that the fourfold increase in cell number during the first six hours of starvation requires proteins synthesized de novo and that new rounds of DNA replication may be initiated during non-growth subsequent to 40–60 min of starvation. While the rate of DNA synthesis during the initial 40–60 min was unaffected by the blockage of protein synthesis, the mechanism conferring autolysis resistance was effectively inhibited.