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Gadolinium ion inhibits loss of metabolites induced by osmotic shock and large stretchâactivated channels in bacteria
- BERRIER, Catherine, COULOMBE, Alain, SZABO, Ildiko, ZORATTI, Mario, GHAZI, Alexandre
- European journal of biochemistry 1992 v.206 no.2 pp. 559-565
- Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Gram-positive bacteria, Xenopus, adenosine triphosphate, cell membranes, gadolinium, ions, lactose, metabolites, oocytes, osmotic stress, solutes
- Bacteria subjected to a hypotonic osmotic shock lose internal ions and also metabolites, without lysis of the cells. We show that the presence in the shock medium, at submillimolar concentrations, of the ion gadolinium, recently shown to block stretchâactivated channels in Xenopus oocytes [Yang, X.âC. & Sachs, F. (1989) Science 243 1068â1071], was sufficient to inhibit shockâinduced release of metabolites such as lactose and ATP in Escherichia coli and ATP in Streptococcus faecalis. Moreover, gadolinium was observed, in patchâclamp experiments, to inhibit the giant stretchâactivated channels of E. coli, S. faecalis and Bacillus subtillis. taken together, these data suggest that stretchâactivated channels are localized in the cytoplasmic membrane of Gramânegative and Gramâpositive bacteria, where they control the efflux of osmotic solutes, thus probably playing a major role in the response to hypotonic osmotic shock.