Enzyme systems, plant cell cultures

Aqueous two-phase cultivation of plant cells was found to be possible when the culture conditions were optimized. The selection of proper polymers and the optimization of their concentrations are needed not only for cell growth, but also for the desirable product partition. Promising examples of the use of aqueous two-phase systems for in situ extraction have been reported recently. However, more detailed and broader studies are necessary to utilize fully the potential of aqueous two-phase systems in plant cell culture. Finally, we believe that the development of fully integrated processes for plant cell cultures will improve the production efficiency of different kinds of secondary metabolites, enzymes, and recombinant proteins. 

DE LUCA, V., BALSEVICH, J., TYLER, R.T., KURZ, W.G.W, Characterization of a novel V-methyltransferase (NMT) from Catharanthus roseus plants. Detection of NMT and other enzymes of the indole alkaloid biosynthetic pathway in different cell suspension culture systems. Plant Cell Rep., 1987,6,458-461. 

There has been much work conducted recently in the area of plant cell culture, or phytoproduction, especially where the product is a plant-unique mixture of Individual flavor substances such as vanilla extract of which vanillin is the major component. As well, the possibility of genetically engineering improved varieties of plants for high yield and consistent quality products is of considerable interest especially for more complex plant-unique flavors. Many flavor compounds are secondary metabolites for which a detailed understanding of their production is not well understood. Presently more knowledge exists In microbial metabolism relative to plant biosynthetic pathways and therefore has resulted in more successful development of microbial-based flavor bioprocessing. As well, scale-up of microbial cultures and isolated enzymes has become relatively common practice while the translation of plant cell culture to large commercial scales is not yet well established. This review will focus on the microbial whole cell and isolated enzyme systems for flavor production. 

Resveratrol oligomers have been obtained from a wide variety of plants (Table (1)). These compounds have been isolated primarily from the roots, wood, and bark however, they have occasionally been extracted from the seeds, fruits, and leaves of some species. In addition, a resveratrol oligomer has been obtained from a plant cell culture. Other resveratrol oligomers have also been obtained following the incubation of 1 with fungal cultures and isolated enzyme systems. 

Pioneers in the use of plant cell systems for studies of xeno-biotic phytotoxicity and metabolism have laid the groundwork for an increasing number of researchers interested in the advantages the cell systems offer (4 6-9). Greater emphasis on the identification of pesticide metabolites formed in whole plants and cell cultures has made evaluation of both systems more meaningful. Although the literature is nearly devoid of studies concerning diaracterization of enzyme systems from plant cell cultures that may be responsible for pesticide metabolism reference to the cell cultures as a convenient source has been made (10). 

Giri A, Dhingra V, GiriCC, Singh A, Ward OP, Narasu ML (2001) Biotransformations using plant cells, organ cultures and enzyme systems current trends and future prospects. Biotechnol Adv 19 175-199... 

Tissue culture, more frequently used as cell culture, enables animal and plant cells to be cultured in large numbers by techniques comparable to those used in microbiology but, because of the fragile nature of the cells, does require special cultural conditions. The culture media used must supply all the essential factors for growth, such as a wide range of amino acids, nucleotides, enzyme co-factors as well as indeterminate factors that can only be supplied in special products, e.g. foetal bovine serum. The environmental conditions must be carefully controlled, particularly pH, and this is frequently maintained by culturing in a bicarbonate buffer system and a carbon dioxide saturated atmosphere. 

The hybrid is able to produce more alkaloids than the basic callus, which is an undifferentiated mass of cells. Alkaloid production in cell cultures can be more successful with the immobihzation of plant cells and enzymes and by using bioreactor systems . Alkaloid produced in cell cultures can be isolated directly from this culture or from young plants grown from this culture. More than 250 alkaloids are reported to be produced by cell-culture techniques. Only a limited number of species have been researched in this respect. The species studied are known to produce alkaloids with special use in applications. The most researched alkaloids produced by cell cultures are mentioned in Table 25. 

The aqueous two-phase system can be applied to plant cell suspension cultures as an in situ extraction method to enhance the production of hydrophobic secondary metabolites or extracellular proteins such as enzymes. Selective removal of the product during bioconversion using plant cells may also be possible in ATPS. Prior to obtaining phy to chemicals with high yields using ATPS, however, reliable cultivation of plant cells in ATPS should be proven. 

Another interesting result concerning the enzyme system of the M. alba cell cultures was obtained at the structure determination experiment of artonin I (31) [43], which has been isolated from an Indonesian moraceous plant Artocarpus heterophyllas, as described in section 2. Artonin I (31) was regarded as a typical Diels-Alder type adduct formed from a chalcone and a flavone, artocarpesin (55)... 

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