Uptake of Alkaloids by Latex Vesicles and Isolated Mesophyll Vacuoles of Chelidonium ntajus (Papaveraceae)

Abstract

Abstract Latex vacuoles of Chelidonium majus (Papaveraceae) naturally sequester protoberberine and benzophenanthridine alkaloids. Isolated vesicles take up a number of other heterologous alkaloids, such as 9,10-dihydroergocryptine, vinblastine, strychnine, nicotine, colchicine, lupanine, and 13-hydroxylupanine, with a strong preference for the indole alkaloids and for nicotine. Kinetic data clearly show that the uptake proceeds via simple diffusion and not by carrier-mediated transport. The alkaloids are concentrated in the vesicles against a concentra­ tion gradient. MgATP has no influence on alkaloid uptake. It is likely that alkaloids are trapped in the vesicles by chelidonic acid (concentration in latex 58 mM, in vesicles 661 mM) which com plexes these alkaloids and thus prevents their rediffusion out of the vesicles. Uptake of these alkaloids by leaf protoplasts and vacuoles of Ch. majus, by vacuoles of suspension-cultured cells of Lupinuspolyphyllus and by rabbit erythrocytes was studied for comparison.