Restoration of cell volume and the reversal of carbohydrate transport and growth inhibition of osmotically upshocked Escherichia coli

Abstract

Resumption of growth in osmotically upshocked Escherichia coli was effected only by an external stimulus (betaine treatment) in severe upshock, but was spontaneous in less severe upshock. In either case, growth resumption was preceded by a reversal of glucose transport inhibition, and that reversal was preceded by a recovery of cell volume. We hypothesize that deformation of the membrane by osmotic stress results in conversion of a membrane component of the transport system to a less functional conformation, which results in the inhibition of transport and the consequent inhibition of growth. Relief of the deformation would then allow recovery to a more functional conformation, reversal of transport inhibition, and then resumption of growth.