Open AccessThe regulation of porin expression in Escherichia coli : effect of turgor stress
Author(s) -
GraemeCook Kathleen A.
Publication year - 1991
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1991.tb04532.x
Subject(s) - osmotic concentration , turgor pressure , osmotic shock , osmolyte , porin , potassium , betaine , osmoregulation , escherichia coli , biochemistry , biology , osmosis , biophysics , chemistry , bacterial outer membrane , membrane , gene , ecology , organic chemistry , salinity
Summary The OmpF and OmpC porins are major outer membrane proteins of Escherichia coli . Their expression is affected by medium osmolarity such that OmpF is normally produced at low osmolarity and OmpC at high osmolarity. Potassium ion accumulation is a major means by which cells maintain their internal osmolarity in high osmolarity medium in the absence of organic osmolytes such as glycine‐betaine. Starvation for potassium causes cells to become turgor stressed. The effect of turgor stress and potassium ion concentration on OmpF and OmpC expression was examined. It was found that ompF gene expression was switched off by turgor stress but there was no concomitant increase in OmpC. Instead, ompC expression responded to the accumulation of potassium ions by the cell in high osmolarity medium.