A Phosphorus-31 Nuclear Magnetic Resonance Study of Phosphate Uptake and Storage in Cultured Catharanthus roseus and Daucus carota Plant Cells

• High resolution "P NMR spectra (103.2 MHz) ofoxygenated Catharanthus roseu8 and Daucus carotacells grown in suspension cultures were obtained usinga solenoidal perfusion probe. The spectra showed resonancesfor various phosphorylated metabolites suchas ATP, ADP, NAD(P)(H), nucleoside diphosphoglucose,and sugar phosphates. The relative levels ofthe phosphorylated metabolites remained constantthroughout the growth curve. No resonances for storagecompounds such as polyphosphates, pyrophosphate,or phytates were observed. Two resolved resonancesfor Pi indicated an intracellular pH of 7.3 and5.7 (or below) for the cytoplasm and vacuoles, respectively.The time course of Pi uptake and storage duringgrowth in fresh culture medium was followed by studyingthe level of vacuolar Pi with 31PN MR (145.7 MHz).Simultaneously, the level of Pi in the culture mediumwas followed with radioactive s2P. C. roseus quicklytakes up all the Pi from the culture medium (maximumrate 1.7 pmol min" g" (dry weight of cells)). The Pi isfirst stored in the vacuoles; subsequently, one part ofthis pool is used to keep a constant cytoplasmic Pi levelwhile another part is apparently accumulated as anNMR invisible Pi store, probably in another cell organelle.In contrast, D. carota does not accumulate Pi inthe vacuoles and consequently it takes up Pi from themedium at a much slower rate (0.05 pmol min" g"(dry weight of cells)). 

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Biochemistry

Biokemi

Biochemistry

Biokemi

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