[Repair of membrane damage caused by low temperature freezing of E. coli cells]

Low temperature freezing of E. coli cells causes an almost complete cell damage. A transfer of the frozen cells to nutritional media results in a repair of some of the damages, i.e. in reconstitution of the barrier stability of the E. coli outer membrane detected by a decrease in sensitivity of the frozen cells to the detergent and lysozyme action and in a change of the cell membrane potential measured by the penetrating ion method. The repair of the cytoplasmic membrane damage is followed by the changes in the permeability barrier for H+ and endogenous substrates, which results in restoration of ATP synthesis as a response to the artificial proton motive force and in an induction of beta-galactosidase synthesis. At the same time the synthesis of the periplasmic protein, alkaline phosphatase, in the cells after repair remains suppressed. An analysis of various biosynthetic processes demonstrated that the inhibition of lipid synthesis completely suppresses the reduction processes, while protein synthesis is not necessary for the repair. The importance of the transmembrane electrochemical proton gradient for the repair processed in E. coli cells was established; the ATP biosynthesis essential for the repair occurs, in all probability, via the glycolytic pathway and not via oxidative phosphorylation.