Changes in macromolecular synthesis and nucleoside triphosphate levels during glycerol-induced growth stasis of Escherichia coli

Abstract

Experiments were performed to determine how glycerol affects macromolecular syntheses and nucleoside triphosphate levels in a strain of Escherichia coli that lacks a functional sn-glycerol-3-phosphate dehydrogenase. The addition of glycerol to cultures of this strain, Lin 8, growing on a gluconeogenic carbon source causes immediate growth stasis (N. R. Cozzarelli, J. P. Koch, S. Hayashi, and E. C. C. Lin, J. Bacteriol. 90:1325-1329, 1965). Immediately after the addition of glycerol to cultures of Lin 8, the syntheses of DNA, RNA, and protein are completely inhibited. Phospholipid synthesis is not inhibited as severely by glycerol. The addition of glycerol to strain Lin 8 also results in a rapid decrease in its nucleoside triphosphate levels. The total intracellular concentration of ATP in strain Lin 8 was reduced by 85% within 30 s after the addition of glycerol. These results suggest that the glycerol-induced inhibition of growth and macromolecular syntheses may be a secondary consequence of the decreased energy supply in this strain. In addition, studies also suggest that phospholipid synthesis can continue (albeit at a reduced rate) under conditions of severe energy limitation.