Phenethyl alcohol resistance in Escherichia coli. I. Resistance of strain C600 and its relation to azide resistance.

ERRAH and KONETZKA (1962) reported that phenethyl alcohol (PEA) selectively and reversibly inhibits DNA synthesis in Escherichia coli. It was subsequently shown that PEA inhibits the initiation of a new cycle of DNA replication in this organism but permits the completion of those cycles initiated before addition of PEA to the medium (TREICK and KONETZKA 1964). We reasoned therefore that genetic and biochemical characterization of strains resistant to PEA might give a clue to our understanding of the nature and function of factor (s) controlling the initiation of the DNA replication cycle in bacteria. Examination of several strains of E. coli K-12 revealed that strain C600 is markedly resistant to PEA compared to other strains tested (WADA and YURA 1965). As will be shown below, strain C600 is resistant to PEA with respect to DNA, RNA, and protein synthesis, initiation of the DNA replication cycle, and membrane permeability to potassium ions. The PEA resistance of this strain is primarily determined by a single gene (pea) located between leu and ai, being extremely close to the latter. The mutational analysis of both the pea and azi genes revealed that the expression of these genes is closely interrelated so as to suggest that they are either identical or closely linked genes whose expression is coordinated perhaps by forming an operon. Evidence also suggests that both genes are involved in the formation, activity or maintenance of cell membrane structure in E. coli.