1974 Volume 20 Issue 1 Pages 21-32
From Escherichia coil CS101, mutants with temperature-sensitive formation of phosphatidylethanolamine (PE) have been isolated by a combination of 3H suicide concentration from the mutagenized cells which incorporated L-serine[3-3H] and a survey of phospholipid synthesis by a direct ion-exchange paper chromatography. Among 306 temperature-sensitive growth mutants, 38 strains were found defective in optimal formation of PE at 42°. Changes in lipid synthesis in these mutants accompanied by abnormalities of growth and morphology have been described. Among them, OS294, the most thermosensitive in PE formation, was further characterized. Upon temperature shift from 27° to 42° of this strain, the formation of PE stopped almost immediately and completely, while that of phosphatidylglycerol (PG) continued and that of cardiolipin (CL) was significantly stimulated. The usefulness of these mutants defective in single lipid synthesis for understanding the possible roles played by individual lipids in cell physiology has been discussed.