Metabolism of glycerol-3-phosphate and phospholipids in a temperature-sensitive lysis mutant of Escherichia coli.

Phospholipid metabolism in a temperature-sensitive lysis mutant of Escherichia coli has been investigated. The incorporation of 32P into the phospholipids of this mutant was negligible, not only at the non-permissive temperature, as was demonstrated earlier, but also at 30C. Furthermore, cultivation of the cells at the non-permissive temperature during 90 min, which is the time required to induce lysis, did not alter the amount of phospholipid per cell. In vitro experiments demonstrated that the enzymes involved in phospholipid biosynthesis are fully active at 42C. Lysis therefore is not directly caused by a defect in phospholipid synthesis. Evidence is presented that the low 32P incorporation is the result of a defective glycerol-3-phosphate dehydrogenase which determines the turnover of the immediate lipid percursor, glycerol-3-phosphate.