OmpC and OmpF are required for growth under hyperosmotic stress above pH 8 in Escherichia coli.
OBJECTIVE
To investigate the requirement of outer membrane porins for osmotic adaptation at alkaline pH in Escherichia coli.


RESULTS
Escherichia coli mutants deficient in ompC, ompF and both genes were constructed and the growth of these mutants was observed at alkaline pH. The growth rate of the mutant deficient in both ompC and ompF was slower than that of the wild type and mutants deficient in one of these genes under hyperosmotic stress at pHs above 8.0. The decreased rate was recovered when a cloned ompC was introduced to the mutant, but the growth recovery with a cloned ompF was partial. Such growth diminution was not observed at pHs below 8.0.


CONCLUSIONS
OmpC and OmpF were shown to participate in hyperosmotic adaptation at alkaline pH in E. coli.


CONCLUSIONS
This study is the first report to demonstrate that OmpC and OmpF are required for hyperosmotic adaptation at pHs above 8.0, but not below 8.0.
Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
M
M
Kaeriyama
K
K
Machida
A
A
Kitakaze
H
H
Wang
Q
Q
Lao
T
T
Fukamachi
H
H
Saito
H
H
Kobayashi
D000222:Adaptation, Physiological; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D004926:Escherichia coli / Q000737:chemistry / Q000254:growth & development / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D009997:Osmotic Pressure; D018272:Porins / Q000235:genetics / Q000502:physiology*
D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D018272:Porins