ABSTRACT
Changes in the content of the furostanol glycosides protodioscin and deltoside, particularly that of the (25S)-isomers of the glycosides, during suspension cultivation of different lines of Nepal yam (Dioscorea deltoidea Wall.) cells of the strain IFR-DM-0.5 has been investigated. The composition of furostanol glycosides has been characterized, and the dynamics of the accumulation of individual glycosides during lengthy subcultivation of cells maintained in flasks or in a barbotage bioreactor has been analyzed. A positive correlation between the growth and accumulation of substances that belonged to the class of furostanol glycosides has been demonstrated for cultured dioscorea cells, whereas the content of some of the individual glycosides varied considerably between the lines of the strain, cultures maintained under different conditions, and even between cells in different phases of the growth cycle. The increased content of (25R)-forms of the glycosides (protodioscin and deltoside) was correlated with a decrease in the cellular growth rate, whereas an increase in culture growth intensity occurred concomitantly to an increase of the amount of (25S)-isomers. This may be indicative of the specific stimulatory effect of (25S)-glycosides, but not the (25R)-forms, on cell proliferation in vitro. Thus, the concentration of (25S)-forms may increase due to the autoselection of cells capable of intensive division during prolonged cultivation.
Subject(s)
Dioscorea/metabolism , Diosgenin/analogs & derivatives , Glycosides/biosynthesis , Plant Cells/metabolism , Saponins/biosynthesis , Dioscorea/cytologyABSTRACT
Peculiarities of breathing of cultures of cells producing biologically active compounds (isoprenoids and alkaloids) were investigated in order to optimize productivity of culture growth and biosynthesis. It had been revealed that studied cultures of cells of Dioscorea deltoidea Wall (producer of furistanol glycosides), Stephania glabra (Roxb.) Miers (producer of stepharin alkaloid) and Polyscias filicifolia Bailey (complex of biologically active agents) differ both in joint breathing activity and in ratio between cytochrome and cyanide-resistant breathing, while changes of rate of total oxygen consumption and activity of alternative oxidase during growth were found to be individual for every investigated culture. Maximum rate of oxygen consumption for cells of D. deltoidea and S. glabra was marked in the period preceding active synthesis of secondary metabolites (lag phase for D. deltoidea and exponential phase for S. glabra). The revealed trends can be used for further monitoring and regulation of growth and biosynthesis of secondary metabolites in producing cell cultures during deep cultivation.
