A 31P nuclear magnetic resonance study of Crithidia luciliae

Ralph Grote, Michael R. Edwards, Raymond S. Norton, William J. O'Sullivan

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)

Abstract

31P NMR has been used to observe phosphorus-containing compounds in both perchloric acid and KOH extracts and in whole cell suspensions of Crithidia luciliae. Cells were grown in Bone and Steinert medium, or in a modified RPMI culture medium and harvested after about 72 h in mid- to late log phase. 31P NMR spectra of the perchloric acid extracts indicated that 3-phosphoglycerate, which is normally at low concentrations in most cells, was the dominant phosphorus-containing compound in the sugar phosphate region. 3-Phosphoglycerate is the end product of glycosomal glycolysis and our finding is consistent with previous observations of the failure to detect prior glycolytic intermediates. Other metabolites observed were ATP, ADP, NAD(P)+, phosphoenolpyruvate and low molecular weight polyphosphates (PPn, n<20). The presence of high molecular-weight polyphosphates was established by spectra recorded on extracts obtained through subsequent treatment of the insoluble fraction with KOH. 31P NMR experiments on whole cells indicated that the average main internal pH of cells in late-log growth phase was approx. pH 7.2±0.1, using the orthophosphate resonance as an indicator. The cells responded to the addition of glucose (final concentration approx. 35 mM) with a decrease in pH, both internal (ΔpH=-0.9 (55 min)-1) and external (ΔpH=-1.3 (15 min)-1). Polyphosphates and ATP could not be observed in whole cell experiments, although perchloric acid extracts of identically treated cells showed no significant depletion of these compounds.

Original languageEnglish
Pages (from-to)109-117
Number of pages9
JournalMolecular and Biochemical Parasitology
Volume42
Issue number1
DOIs
Publication statusPublished - 1990
Externally publishedYes

Keywords

  • P magnetic resonance spectroscopy
  • Crithidia luciliae
  • Glucose metabolism
  • Kinetoplastida
  • pH
  • Polyphosphate

Cite this