Secondary Metabolites in Cell Cultures

From Table XII it is obvious that the alkaloid levels found in the cell and tissue cultures of Nicotiana species vriry widely. The cultures do produce a variety of other secondary metabolites as well sterols and triterpenes 245,246), ubiquinone 247), cinnamoyl putrescines 248-251), and the phytoalexin capsidiol and related sesquiterpenes 252-254). 

Patents Concerning Production of Nicotine in Plant Cell AND Tissue Cultures 

Shio and S. Ota. Ajinomoto Co., Ltd. Jpn. Kokai, JP 480912187, 28 Nov 1973 Showa. JP 72-18357, 22 Feb 1972. Alkaloid production by tissue culture. Chem. Abstr. 80, 118396p. 

Weaving, A. J. N. Bolt, D. J. Barlett, and S. W. Purkins. Imperial Group PLC. GB 2203022, 10-12-1988. Smoking material containing substrate of tobacco cells or plant material and cellulosic material with mixtures of lactose and glucose. 

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Tab. 4 Comparison of product yield of secondary metabolites in cell culture ...

Several important alkaloids have been isolated from Catharanthus roseus plants ajmalicine (34) and serpentine (35) from the root, and the dimeric alkaloids vinblastine (36) and vincristine (37) from the leaves. Therefore, much research has been done on production of these alkaloids by means of plant cell culture. Catharanthus roseus is, in fact, one of the most widely studied plants for the production of secondary metabolites in cell culture systems. We here discuss the two types of alkaloids separately. Table XXIX summarizes patents concerning the production of alkaloids by means of cell cultures of C. roseus. 

Ahn, J.K. Lee, W.Y. Park, S.Y. (2003). Effect of nitrogen source on the cell growth and production of secondary metabolites in bioreactor cultures of Eleutherococcus senticosus. Korean Journal of Plant Biotechnology, Vol.30, No.3, pp. 301-305, ISSN 1598-... 

Valluri, J.V. 2009. Bioreactor production of secondary metabolites from cell cultures of periwinkle and sandalwood. In Jain, S.K. and Saxena, P.K. (eds.) Protocol for In Vitro Cultures and Secondary Metabolites Analysis of Aromatic and Medicinal Plants, Serious Methods in Molecular Biology, Vol. 547. Humana Press Inc., Totowa, NJ, p. 325. 

Other responses, such as formation of phytoalexins, are more specific (Chappell and Hahlbrock, 1984 Luckner, 1980). It has been shown that production of secondary compounds in cell cultures also can be enhanced by environmental stress. Treatment of cell cultures with fimgal, bacterial, or plant cell wall materials often results in the formation of a number of flavonoids, stilbenes, terpenoids, anthraquinones, rutacridone alkaloids, sanguinarine, and gossypol (Eilert, 1987 Heinstein 1985). In some cases, production of these metabolites is transient. Clearly, we need more information on the basic principles of the defensive response, such as structures and perception of defensive signals, transduction, and translation of these signals into a response (Luckner, 1980 Wink, 1987). 

Schroeder, W. and Bohm, H., Once more secondary metabolite concentrations in whole plants and in cell cultures derived therefrom, J. Plant Physiol, 145,126,1995. Yang, R.Y.K. et al., Plant-cell bioreactors with simultaneous electropermeabilization and electrophoresis, J. BiotechnoL, 100, 13, 2003. 

J. Guern, J. P. Renaudin, S. C. Brown, The compartmentation of secondary metabolites in plant cell cultures. Cell Culture and Somatic Cell Genetics of Plants. Vol. 4 (F, Constabel and 1. K. Vasil, eds.). Academic Press, San Diego, 1987, p. 43. A. L. Samuels, M. Fernando, and A. D. M. Glass, Immunofluorescent localization of plasma membrane H -ATPase in barley roots and effects of K nutrition. Plant Physiol. 99 1509 (1992). 

In situ Extraction for the Enhanced Production of Secondary Metabolites in Plant Cell Cultures. 66... 

Secondary metabolites in plant cell culture are typically stored within the vacuolar compartments of the cells. Small amounts of metabolites are usually excreted into the medium or may appear in the medium due to cell lysis. In some cases, active transport of metabolites adjusts intracellular and extracellular levels in response to cellular conditions. Poor yields of secondary substances released into the medium may be caused by several factors. In those cases where low yield is due to cellularly mediated regulation of the ratio between intracellular and extracellular product concentrations, processes which reduce net medium concentrations such as enzymatic or non-enzymatic degradation, or volatility, should increase net production by depleting the level of the secondary substances in the culture medium. By using the so-called in situ extraction method, the accumulation of a secondary substance inside the cell, in the culture medium, and in the extraction phase should approach an equilibrium, which... 

In situ extraction for the enhanced production of secondary compounds can be applied in bioreactors. In bioreactor systems low productivity is an important bottleneck, and only a few products are potential candidates for economically feasible production of secondary metabolites using plant cell biotechnology. Several approaches to increase the productivity of secondary metabolites in bioreactors have been made [12]. Among them elicitation and in situ extraction are typical techniques of current interest. Application of these techniques to cell culture systems sometimes increased the productivity to such an extent that they have sometimes been viewed as the gateway to commercial success [10]. However, general rules or suggestions concerning these techniques cannot be made because of the different characteristics of the cell culture systems. 

Guern, J., Renaudin, J.P and Brown, S.C. (1987) The compartmentation of secondary metabolites in plant cell cultures, in Cell Culture and Somatic Cell Genetics (eds R Constabel and I. Vasil). Academic Press, New York, pp. 43-76. 

Production of Secondary Metabolites in Plant Cell Cultures... 

The presence or absence of phosphate ions plays an important role in the expression and accumulation of some secondary products. Zenk et al. (47) have demonstrated a 50% increase in anthraquinone accumulation in cell cultures of Morinda citrofolia when phosphate was increased to a concentration of 5g7h In suspension cultures of Catharanthus roseus, the overall accumulation of secondary metabolites like tryptamine and indole alkaloids has been shown to occur rapidly when cells were shifted to a medium devoid of phosphate (48,49). A study on the uptake of phosphate and its effect on phenylalanine ammonia lyase and the subsequent accumulation of cinnamoyl putrescine in cell suspension cultures of Nicotiana tabacum demonstrated marked sensitivity to phosphate concentration (5DX Enhanced phenylalanine ammonia lyase activity and increased production of cinnamoyl putrescine was induced by subculture onto phosphate-free medium while suppression of these effects and stimulation of growth was observed with phosphate concentrations of 0.02-0.5uM. Interestingly, phenylalanine ammonia lyase activity is stimulated by increasing phosphate concentrations in cell suspension of Catharanthus roseus (51). 

With a few exceptions, the characteristic problem of cultivation of plant explants in in vitro cultures is a low production of secondary metabolites by these cultures. One of the methods which can achieve an increase in the production of natural substances in in vitro cultures, is elicitation of cell cultures with biotic elicitors. For example, hairy root cultures of Cassia obtusifolia L. clones transformed with Agrobacterium rhizogenes strain 9402 were established to investigate anthraquinone production. It was found that changes of the elements in the culture medium and the addition of rare earth element Eu3+ can greatly influence the contents of free anthraquinones in the hairy root [320],... 

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