Genetic Analysis of an Escherichia coli Syndrome

Abstract

A mutant strain of Escherichia coli that fails to recover from prolonged (72 hr) starvation also fails to grow at 43 C. Extracts of this mutant strain show an increased ribonuclease II activity as compared to extracts of the parental strain, and stable ribonucleic acid is degraded to a larger extent in this strain during starvation. Ts + transductants and revertants were tested for all the above-mentioned phenotypes. All the Ts + transductants and revertants tested behaved like the Ts + parental strain, which suggests that all the observed phenotypes are caused by a single sts (starvation-temperature sensitivity) mutation. The reversion rate from sts − to sts + is rather low but is within the range of reversion rates for other single-site mutations. Three-point transduction crosses located this sts mutation between the ilv and rbs genes. The properties of sts + / sts − merozygotes suggested that the Ts − phenotype of this mutation is recessive.