NMR NATURAL-ABUNDANCE ESTIMATION OF C-13-METABOLIC SOLUTES IN NORMAL AND HABITUATED SUGAR-BEET CELL-LINES

NMR (nuclear magnetic resonance) spectroscopy was used to identify met abolic solutes in one normal and two habituated sugarbeet cell lines ( Beta vulgaris L. altissima) obtained from the same mother strain. This technique was applied to investigate the intracellular naturally occu rring C-13 isotopes (1.1% of total natural carbon) in living sugarbeet suspension cells and perchloric cell extracts. A combination of H-1, C-13, double-quantum filter correlation spectroscopy, heteronuclear mu ltiple-bond correlation. and heteronuclear multiple-quantum coherence spectra from perchloric cell extracts enabled us to identify the main compounds in the different extract solutions. This was verified by spi king the solutions with small amounts of reference compounds to exclud e the influence exerted by pH on the chemical shifts of the different compounds in the H-1 and C-13 spectra. The comparison of the three sug arbeet cell lines' NMR spectra showed the presence of sucrose, glucose , and fructose in the three strains. On the other hand, it revealed a strong discrepancy between metabolic solutes. Spectra from the habitua ted lines showed the presence of glutamine. Some amino acids such as a lanine or valine, and unidentified signals corresponding to aromatic r ings were only characterized in the habituated nonorganogenic cells. O n the basis of these C-13 NMR data we assumed that the discrepancy bet ween the different sugarbeet cell Lines could be due to an increase in the metabolic activity of the habituated cell lints in relation to th eir autonomous growth.