Isolation and characterization of respiratory-deficient mutants of Escherichia coli K-12

Abstract

Several mutants ofEscherichia coli K-12 Moody, J. Biol. Chem., in press). Though lesions in both aerobic and anaerobic respiratory pathways have been described (for a review, see reference 13), the effect of such mutations on the regulation of enzymes involved in aerobic survival has received little attention.In this work, we isolated mutants which were unable to grow aerobically on media devoid of a source of fermentable carbohydrate. Changes in the aerobic metabolism and heme and cytochrome content were evaluated in one of the mutants. We also examined aerobic induction of MnSOD, catalase, and peroxidase in this mutant. The results of these studies form the body of this report.

The development of an efficient system for heterologous expression of cytochrome P450s in Escherichia coli using hemA gene co-expression

“…Heme deWcient mutants of E. coli have retarded growth forming tiny dwarf colonies on rich media and are insensitive to intermediate concentrations of aminoglicoside antibiotics due to the lack of a transmembrane potential on the inner membrane, preventing uptake of the antibiotic into the cell [19]. This property was used successfully in initial selection of 5-ALA auxotrophs of E. coli by mini-Tn5 mutagenesis.…”

Growth of an Escherichia coli mutant deficient in respiration

“…These results indicate that E. coli is able to grow without respiration even if oxygen is present. Schellhorn and Hassan [13] isolated a respiratory‐deficient mutant of E. coli which was able to grow aerobically. They stated that the growth rate of their mutant was low in the presence of oxygen, but both VSR723 and H500 grew more rapidly under aerobic conditions than O 2 ‐limiting conditions.…”

AnEscherichia coliMutant Conditionally Altered in Respiratory Chain Components

“…Except for hemA, no other heme gene maps nears lct* (3,28). A leaky heme deficiency could account for the normal R25 m-lactate PMS reductase activity in the presence of reduced levels of cytochromes and oxidase activities for NADH and m-lactate.…”