A THERMOSENSITIVE MUTANT OF ESCHERICHIA COLI WITH A DEFECT IN THE PROCESS OF CELL DIVISION

Abstract

A thermosensitive mutant of Escherichia coli (E. coli strain ts612) was isolated by the transduction of polA⁺ as a selective marker with phage Plc which had been mutagenized with hydroxylamine. The mutation was mapped between ilv (74.7min) and metE (75.5min). When the incubation temperature of this mutant was shifted from 30° to 42°, the cell division was interrupted immediately after the shift of temperature, although the optical density at 660nm of the culture continued to increase for 90min. The mutant did not support the multiplications of phages T4 and lambda at 42°, while it allowed the growth of phage T7. Electrophoretic analysis of membrane proteins of the mutant suggested that a part of the membrane protein was diminished when the mutant was incubated at the restrictive temperature.