Display options
Share it on

Plant Physiol. 1993 Jun;102(2):573-578. doi: 10.1104/pp.102.2.573.

The Use of Fura-2 Fluorescence to Monitor the Movement of Free Calcium Ions into the Matrix of Plant Mitochondria (Pisum sativum and Helianthus tuberosus).

Plant physiology

M. Zottini, D. Zannoni

Affiliations

  1. Department of Biology, Biochemistry Laboratory, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.

PMID: 12231846 PMCID: PMC158814 DOI: 10.1104/pp.102.2.573

Abstract

Purified mitochondria isolated from pea (Pisum sativum L. cv Alaska) stems and Jerusalem artichoke (Helianthus tuberosus L. cv OB1) tubers were loaded with the acetoxymethyl ester of the fluorescent Ca2+ indicator fura-2. This made possible the continuous monitoring of free [Ca2+] in the matrix ([Ca2+]m) without affecting the apparent viability of the mitochondria. Pea stem mitochondria contained an initial [Ca2+]m of approximately 60 to 100 nM, whereas [Ca2+]m was severalfold higher (400-600 nM) in mitochondria of Jerusalem artichoke tubers. At low extramitochondrial Ca2+ concentrations ([greater than or equal to]100 nM), there was an energy-dependent membrane potential increase in [Ca2+]m; the final [Ca2+]m was phosphate-dependent in Jerusalem artichoke but was phosphate-independent in pea stem mitochondria. The data presented indicate that (a) there is no absolute requirement for phosphate in Ca2+ uptake; (b) plant mitochondria can accumulate external free Ca2+ by means of an electrophoretic Ca2+ uniporter with an apparent affinity for Ca2+ (Km approximately 150 nM) that is severalfold lower than that measured by conventional methods (isotopes and Ca2+-sensitive electrodes); and (c) [Ca2+]m is within the regulatory range of mammalian intramitochondrial dehydrogenases.

References

  1. Rev Physiol Biochem Pharmacol. 1985;102:1-72 - PubMed
  2. Braz J Med Biol Res. 1987;20(5):635-8 - PubMed
  3. Biochem J. 1984 Feb 15;218(1):235-47 - PubMed
  4. Plant Physiol. 1992 Feb;98(2):452-7 - PubMed
  5. Biochem J. 1989 Mar 15;258(3):923-6 - PubMed
  6. Biochem J. 1987 Dec 1;248(2):313-28 - PubMed
  7. Biochem Biophys Res Commun. 1983 Aug 12;114(3):1176-81 - PubMed
  8. Plant Physiol. 1992 Jul;99(3):1037-43 - PubMed
  9. Biochemistry. 1976 Aug 24;15(17):3834-42 - PubMed
  10. Plant Physiol. 1990 Jul;93(3):841-5 - PubMed
  11. Biochem Biophys Res Commun. 1987 Nov 30;149(1):40-5 - PubMed
  12. J Biol Chem. 1985 Mar 25;260(6):3440-50 - PubMed
  13. Nature. 1985 Apr 18-24;314(6012):622-5 - PubMed
  14. Eur J Biochem. 1991 Dec 5;202(2):617-23 - PubMed
  15. Biochem J. 1987 Dec 1;248(2):609-13 - PubMed
  16. Anal Biochem. 1976 May 7;72:248-54 - PubMed
  17. Biochem J. 1984 Mar 1;218(2):415-20 - PubMed
  18. Biochim Biophys Acta. 1989 Mar 23;973(3):420-7 - PubMed
  19. Nature. 1981 Apr 9;290(5806):527-8 - PubMed
  20. Arch Biochem Biophys. 1973 Jul;157(1):183-96 - PubMed
  21. J Biol Chem. 1986 Jul 5;261(19):8799-804 - PubMed

Publication Types