RRC ID 30067
Author Zilberstein D, Agmon V, Schuldiner S, Padan E.
Title Escherichia coli intracellular pH, membrane potential, and cell growth.
Journal J. Bacteriol.
Abstract We studied the changes in various cell functions during the shift to alkaline extracellular pH in wild-type Escherichia coli and in strain DZ3, a mutant defective in pH homeostasis. A rapid increase in membrane potential (delta psi) was detected in both the wild type and the mutant immediately upon the shift, when both cell types failed to control intracellular pH. Upon reestablishment of intracellular pH - extracellular pH and growth in the wild type, delta psi decreased to a new steady-state value. The electrochemical proton gradient (delta muH+) was similar in magnitude to that observed before the pH shift. In the mutant DZ3, delta psi remained elevated, and even though delta muH+ was higher than in the wild type, growth was impaired. Cessation of growth in the mutant is not a result of cell death. Hence, the mutant affords an interesting system to explore the intracellular-pH-sensitive steps that arrest growth without affecting viability. In addition to delta muH+, we measured respiration rates, protein synthesis, cell viability, induction of beta-galactosidase, DNA synthesis, and cell elongation upon failure of pH homeostasis. Cell division was the only function arrested after the shift in extracellular pH. The cells formed long chains with no increase in colony-forming capacity.
Volume 158(1)
Pages 246-52
Published 1984-4
PMID 6325389
PMC PMC215405
MeSH Bacterial Proteins / biosynthesis Cell Division DNA, Bacterial / biosynthesis Enzyme Induction Escherichia coli / genetics Escherichia coli / growth & development Escherichia coli / metabolism* Homeostasis Hydrogen-Ion Concentration Kinetics Membrane Potentials Mutation Oxygen Consumption Protons beta-Galactosidase / biosynthesis
IF 3.234
Times Cited 132
Prokaryotes E. coli ME8312