Carbonyl cyanide-m-chlorophenyl hydrazone-resistant Escherichia coli mutant that exhibits a temperature-sensitive unc phenotype

Abstract

Two spontaneous E. coli mutant strains which are resistant to an oxidative phosphorylation uncoupler, carbonyl cyanide-m-chlorophenyl hydrazone, were isolated. Strain CM22 (ccr-2) was resistant to anthoer uncoupler, pentachlorophenol, and to the inhibitors of proton-translocating ATPase, namely tributylin and sodium azide. Carbonyl cyanide-m-chlorophenyl hydrazone or pentachlorophenol administered to cell suspensions of strain CM22 did not cause a pH change induced by H+ influx, and a similar result was obtained with everted particles. The respiratory rate of strsin CM22 with succinate was twice that of wild-type strain KH434. When carbonyl cyanide-m-chlorophenyl hydrazone was administered, a stimulation of O2 uptake was observed in wild-type strain KH434 but not in the mutant strain CM22. Strain CM22 did not grow on succinate at 42°C. Isolation of a true revertant at a frequency of 10-8 demonstrated that the pleiotropic phenotype was induced by a single mutation. P1 transduction indicated that the mutant allele, ccr-2, was cotransduced with the ilv genes at a frequency of about 55%.