Effect of hydroxyurea on the protein content and synthesis in normal and tumorous tobacco tissues cultured in vitro.
An over 9 per cent increase was found in the protein content of callus and tumorous tissues of Nicotiana tabacum cultured for 39 days in a medium with an addition of hydroxyurea at a concentration of 100 mg/l. The inhibitory effect of this compound on incorporation of [14C]leucine was demonstrated, differences in the intensity of labelling between the nucleus and cytoplasm being present only in the tumorous tissue. These differences may indicate either disturbances in the migration of proteins from cytoplasm to nuclei or a specific blockade of histone synthesis. Hydroxyurea inhibits incorporation of [3H]arginine in callus tissues, whereas in tumorous tissues, apart from inhibition (at 75 and 100 mg HU/1), the stimulation of incorporation of this amino acid was observed (at 10 and 50 mg HU/1). The inhibitory effect of hydroxyurea on incorporation of [3H] lysine was demonstrated in both tissues examined, but it was stronger in the callus tissue. On the basis of the results concerning the influence of hydroxyurea on the content and synthesis of nucleic acids [4, 5] and the results of the present study it may be supposed that this compound induces unbalanced growth of cells of both tissues (inhibition of DNA and RNA synthesis and simultaneous accumulation of proteins), thus leading to their death.
D001120:Arginine / Q000378:metabolism; D006651:Histocytochemistry; D006918:Hydroxyurea / Q000494:pharmacology*; D007930:Leucine / Q000378:metabolism; D008239:Lysine / Q000378:metabolism; D059828:Plant Cells; D010935:Plant Diseases; D010940:Plant Proteins / Q000096:biosynthesis*; D010944:Plants / Q000187:drug effects / Q000378:metabolism*; D010947:Plants, Toxic; D014176:Protein Biosynthesis / Q000187:drug effects; D014026:Nicotiana / Q000187:drug effects / Q000378:metabolism
D010940:Plant Proteins; D001120:Arginine; D007930:Leucine; D008239:Lysine; D006918:Hydroxyurea