Skip to main content
PMC home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1977 Jun;130(3):1017–1023. doi: 10.1128/jb.130.3.1017-1023.1977

Effects of potassium ions on the electrical and pH gradients across the membrane of Streptococcus lactis cells.

E R Kashket, S L Barker
PMCID: PMC235322  PMID: 16864

Abstract

Bacteria transduce and conserve energy at the plasma membrane in the form of an electrochemical gradient of hydrogen ions (deltap). Energized cells of Streptococcus lactis accumulate K+ ions presumably in exchange for H+. We reasoned that if the movement of H+ is limited, then an increase in H+ efflux, effected by potassium transport inward, should result in changes in the steady-state deltap. We determined the electrical gradient (deltapsi) from the fluorescence of a membrane potential-sensitive cyanine dye, and the chemical H+ gradient (deltapH) from the distribution of a weak acid. The deltap was also determined independently from the accumulation levels of the non-metabolizable sugar thiomethyl-beta-galactoside. KCl addition to cells fermenting glucose or arginine at pH 5 changed the deltap very little, but lowered the deltapsi, while increasing the deltapH. At pH 7, the deltapH only increased slightly; thus, the decrease in deltapsi, effected by addition of potassium ions, resulted in a lowered steady-state deltap. These effects were shown not to be due to swelling or shrinking of the cells. Thus, in these nongrowing cells, under conditions of energy utilization for the active transport of K+, the components of deltap can vary depending on the limitations on the net movement of protons.

Full text

PDF
1017

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Collins S. H., Hamilton W. A. Magnitude of the protonmotive force in respiring Staphylococcus aureus and Escherichia coli. J Bacteriol. 1976 Jun;126(3):1224–1231. doi: 10.1128/jb.126.3.1224-1231.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Harold F. M., Baarda J. R., Pavlasova E. Extrusion of sodium and hydrogen ions as the primary process in potassium ion accumulation by Streptococcus faecalis. J Bacteriol. 1970 Jan;101(1):152–159. doi: 10.1128/jb.101.1.152-159.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Harold F. M. Conservation and transformation of energy by bacterial membranes. Bacteriol Rev. 1972 Jun;36(2):172–230. doi: 10.1128/br.36.2.172-230.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Harold F. M., Papineau D. Cation transport and electrogenesis by Streptococcus faecalis. II. Proton and sodium extrusion. J Membr Biol. 1972;8(1):45–62. doi: 10.1007/BF01868094. [DOI] [PubMed] [Google Scholar]
  5. Hoffman J. F., Laris P. C. Determination of membrane potentials in human and Amphiuma red blood cells by means of fluorescent probe. J Physiol. 1974 Jun;239(3):519–552. doi: 10.1113/jphysiol.1974.sp010581. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kashket E. R., Wilson T. H. Proton-coupled accumulation of galactoside in Streptococcus lactis 7962. Proc Natl Acad Sci U S A. 1973 Oct;70(10):2866–2869. doi: 10.1073/pnas.70.10.2866. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Kashket E. R., Wilson T. H. Protonmotive force in fermenting Streptococcus lactis 7962 in relation to sugar accumulation. Biochem Biophys Res Commun. 1974 Aug 5;59(3):879–886. doi: 10.1016/s0006-291x(74)80061-6. [DOI] [PubMed] [Google Scholar]
  8. Kashket E. R., Wilson T. H. Role of metabolic energy in the transport of -galactosides by Streptococcus lactis. J Bacteriol. 1972 Feb;109(2):784–789. doi: 10.1128/jb.109.2.784-789.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Michel H., Oesterhelt D. Light-induced changes of the pH gradient and the membrane potential in H. halobium. FEBS Lett. 1976 Jun 1;65(2):175–178. doi: 10.1016/0014-5793(76)80473-5. [DOI] [PubMed] [Google Scholar]
  10. Padan E., Zilberstein D., Rottenberg H. The proton electrochemical gradient in Escherichia coli cells. Eur J Biochem. 1976 Apr 1;63(2):533–541. doi: 10.1111/j.1432-1033.1976.tb10257.x. [DOI] [PubMed] [Google Scholar]
  11. Ramos S., Schuldiner S., Kaback H. R. The electrochemical gradient of protons and its relationship to active transport in Escherichia coli membrane vesicles. Proc Natl Acad Sci U S A. 1976 Jun;73(6):1892–1896. doi: 10.1073/pnas.73.6.1892. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Renthal R., Lanyi J. K. Light-induced membrane potential and pH gradient in Halobacterium halobium envelope vesicles. Biochemistry. 1976 May 18;15(10):2136–2143. doi: 10.1021/bi00655a017. [DOI] [PubMed] [Google Scholar]
  13. Scherrer R., Gerhardt P. Molecular sieving by the Bacillus megaterium cell wall and protoplast. J Bacteriol. 1971 Sep;107(3):718–735. doi: 10.1128/jb.107.3.718-735.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Waggoner A. Optical probes of membrane potential. J Membr Biol. 1976 Jun 30;27(4):317–334. doi: 10.1007/BF01869143. [DOI] [PubMed] [Google Scholar]
  15. Wilson T. H., Kusch M. A mutant of Escherichia coli K 12 energy-uncoupled for lactose transport. Biochim Biophys Acta. 1972 Mar 17;255(3):786–797. doi: 10.1016/0005-2736(72)90391-4. [DOI] [PubMed] [Google Scholar]
  16. Zarlengo M. H., Schultz S. G. Cation transport and metabolism in Streptococcus fecalis. Biochim Biophys Acta. 1966 Oct 10;126(2):308–320. doi: 10.1016/0926-6585(66)90068-9. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES