Abstract:

Apoptosis, both in animal and plant cells, is usually analyzed by observing and detecting the characteristic morphological and biochemical changes in nuclei, organelles such as mitochondria and cell membranes. Using ¹H-NMR we have found a correlation between the progression of apoptosis and ¹H-NMR methylene signal intensity in cultured tobacco (Nicotiana tabacum L. cv. BY-2) and carrot (Daucus carota L.) cells. The increase in the methylene resonance signal intensity which reflects the alterations in membrane lipids and accordingly in the biophysical and biochemical characteristics of cell membrane during apoptosis was found to be closely associated with nuclear changes as detected by DNA laddering assay and the TUNEL procedure. The rise of methylene resonance signal intensity was evident in apoptotic plant cells induced by various factors including nicotinamide, menadione, heat shock and hydroxyl radicals, but it was not found in necrotic cells. To our knowledge, this is the first report of the ¹H-NMR detection of apoptosis which is closely associated with the increase in methylene resonance signal intensity in plants.

Key words: apoptosis, plant cells, ¹H-NMR, membrane lipids