Oxidative phosphorylation and the realkalinization of intracellular pH during recovery from anoxia in Artemia franciscana embryos

Kurt E. Kwast, Joseph I. Shapiro, Bernard B. Rees, Steven C. Hand

Research output: Contribution to journalArticlepeer-review

Abstract

The contribution of mitochondrial oxidative phosphorylation to the realkalinization of intracellular pH (pHi) and resynthesis of purine nucleotides during recovery from anoxia was investigated in embryos of Artemia franciscana by assessing the sensitivity of mitochondrial respiration to pH, calculating proton consumption by oxidative phosphorylation, and measuring changes in pHi using 31P nuclear magnetic resonance. Following short-term anoxia, pHi increased from 6.7 to 7.7 during 20 min of aerobic recovery and was temporally correlated with a large increase in ATP. State 3 respiration rates of isolated mitochondria were not substantially compromised at the acidic pH corresponding to the pHi during anoxia (pH 6.3-6.8) compared to values obtained at pH 7.7. Both state 3 respiration rates and respiratory control ratios exhibited broad, substrate-specific pH optima, whereas state 4 respiration rates increased gradually with increasing pH. P:O flux ratios were near their mechanistic limits and did not vary appreciably with pH below 7.5. Estimates of intracellular buffering capacity indicate that between 18 and 37 mmol H+ (1 cytosol)-1 must be consumed to elevate pHi from 6.7 to 7.7. Phosphorylation of mono- and diphosphate purine-nucleotides during the first 20 min of recovery may account for the consumption of up to 4.79 mmol H+ (1 cytosol)-1. An additional 4.77 to 8.18 mmol H+ (1 cytosol)-1 may be consumed through the oxidation of mono- or dicarboxylic acids, respectively, in the Krebs cycle. Taken together, these data are consistent with a role for oxidative phosphorylation in the realkalinization of pHi and resynthesis of purine nucleotides in A. franciscana embryos during recovery from anoxia.

Original languageEnglish (US)
Pages (from-to)5-12
Number of pages8
JournalBBA - Bioenergetics
Volume1232
Issue number1-2
DOIs
StatePublished - Nov 21 1995

Keywords

  • (Artemia)
  • Anoxia
  • Mitochondrion
  • Oxidative phosphorylation
  • Respiration
  • pH, intracellular

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

Fingerprint

Dive into the research topics of 'Oxidative phosphorylation and the realkalinization of intracellular pH during recovery from anoxia in Artemia franciscana embryos'. Together they form a unique fingerprint.

Cite this