Plants transgenic

Plants are regarded as potentially attractive recombinant protein producers for a number of reasons, including  

Hepatitis B surface antigen Tobacco 0.007% of soluble leaf protein 

However, a number of potential disadvantages are also associated with the use of plant-based expression systems, including  

For these reasons, as well as the fact that additional tried-and-tested expression systems are already available, production of recombinant therapeutic proteins in transgenic plant systems has not as yet impacted significantly on the industry. 

In order to overcome environmental concerns in particular, some companies are investigating the use of engineered plant cell lines as opposed to intact transgenic plants in the context of biopharmaceutical production. One company (DowAgroSciences) gained approval in 2006 for a veterinary subunit vaccine against Newcastle disease in poultry produced by such means. 

Er5hhropoietin Tobacco 0.003% of total soluble plant protein 

Human serum albumin Potato 0.02% of soluble leaf protein 

Transgenic plants appear to be the most cost-effective PHA prodncer becanse in principle the PHA are produced from carbon dioxide, water and sunlight. If transgenic plants were to 

At the moment, strategies for the production of transgenic plants are already used for maize, tobacco, potato, and rice. The main purpose is to increase their resistance toward diseases [63]. Some plants also get newly introduced products, such as vitamins [64]. Another purpose of transgenic plants is their use for production of vaccines for instance hepatitis B vaccine 

There are a number of examples of the development of plants for pharmaceutical protein production including antibodies, vaccines, and other bioactive proteins (Daniell et al., 2001 Daniell, 2006 Ma et al., 2005a, b, c Twyman et al., 2003) as well as consideration of the issues surrounding regulatory issues of the use of transgenic plants for pharmaceutical protein applications (Ma et al., 2005b Sparrow et al., 2007 Spok, 2007). 

Four basic strategies for recombinant protein expression in plants are transient expression, stable nuclear transformed plants, chloroplast transformed plants, and suspension cultures derived from stable transgenic lines. 

Transgenic plant systems have the potential to produce recombinant proteins on a commodity scale (Kusnadi et al., 1997) due to the low cost of growing plants and because scale-up of production simply requires sewing seeds over a greater field area. As such they offer almost unlimited scalability (Giddings, 2001). It is estimated by Kusnadi et al. (1997) that transgenic plants can produce pharmaceutical proteins at between 10 and 50-fold lower cost than microbial fermentation systems, and 1,000 times lower than mammalian cell culture systems (Hood et al., 2002). 

The process of protein production must be optimized for maximum yield while allowing the plant to function correctly without growth being adversely affected. When considering construct design one must consider carefully a number of factors as outlined below. 

Although tobacco is probably the most common host, a range of plant hosts have been shown to function in cell suspension cultures. For example, rice cell cultures produced human growth hormone in the medium at 57 mg/L and showed similar biological activity to human growth factor produced by E. coli (Kim et al., 2008b). Lee et al. (2007) produced biologically active human 

Jerusalem artichoke has been the source of genetic material for the transformation of other crop species. Numerous transformations have been conducted with cultivated sunflower, and some with sunflower-Jerusalem artichoke hybrids, but no attempt to date has been made to improve Jerusalem artichoke as a crop via genetic transformation. However, Jerusalem artichoke is a classic tissue culture species (see Section 9.3), while much of the experience gained with transgenic sunflower is applicable to Jerusalem artichoke. Therefore, the means of transforming Jerusalem artichoke are largely in place. 

Ever since the first successful expression of PHA biosynthetic enzymes in plants [169], which resulted in the accumulation of small amounts ( 0.1% of the DCW) of P(3HB), considerable knowledge regarding the potential of this system has been obtained. Subsequent studies showed that, when PHA accumulation is targeted in the plastids, a P(3HB) content of up to 14% of the DCW was accumulated by one of the transgenic plants [170]. Later, upon the expression of a threonine deaminase protein, in addition to enzymes of PHA biosynthesis, it was demonstrated that plants can be directed to produce a copolymer of P(3HB-co-3HV) [171]. This achievement is of considerable interest because of the poor physical properties of the P(3HB) homopolymer. Later, it was shown that the targeting of a PHA synthase from P. aeruginosa into the peroxisomes of Arabidopsis thaliana, results in the accumulation of PHAmcl [172]. These achievements show that it is indeed possible to produce various kinds of PHA homopolymers and copolymers in transgenic plants. 

Plant platforms for producing PHA have been recently reviewed [176, 177]. An example of high yields is reported in a genetically modified tobacco plant Nicotiana tabacum) transformed to contain Acinetobacter sp., genes. The modified tobacco produced between 17 and 19% (w/w) polyhydroxybutyrate (PHB) in leaf tissues [178]. 

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Knight, M. R., Campbell, A. K., Smith, S. M., and Trewavas, A. J. (1991). Transgenic plant aequorin reports the effects of touch and cold-shock and elicitors on cytoplasmic calcium. Nature 352 524-526. 

Mayerhofer, R., Langridge, W. H. R., Cormier, M. J., and Szalay, A. A. (1995). Expression of recombinant Renilla luciferase in transgenic plants results in high levels of light emission. Plant. J. 7 1031-1038. 

Poly(hydroxyalkanoic acid)s BiopoF Monsanto Environmental Biosynthesis by bacteria or transgenic plants... 

Ito H. Higara S. Tsugava H. et al. (2000) Xylem-spedfic expression of wound inducible rice peroxidases genes in transgenic plants // Plan Sci. V. 155. P. 85-100. 

Schell, J. (1987). Transgenic plants on tools to study the molecular organization of plant genes. Science, 237,1176-83. 

Vaeck, M., Reynaerts, A., Hofte, H., Jansens, S., De Beukeleer, M., Dean, C., Zabeau, M., Van Montagu, M. Leemans, J. (1987). Transgenic plants protected from insect attack. Nature, 328, 33-7. 

Figure 4. Inhibition of A. nigerand F. moniliforme endopolygalacturonase by PGIP purified fom tomato transgenic plants (A) and from bean (B).

Products released by the action of PL have previously been reported to act as elicitors of plant defense reactions (24,25,26,27). Accordingly, the transgenic plants described in this report provides an excellent mutant collection for the study of factors conferring resistance against Envinia carotovora bacteria. 

In the present study we used transgenic plants to analyse the amount of control exerted by an additional vacuolar invertase on the allocation of carbohydrates to the plant cell wall. Since physical parameters indicated a significant modification in the thermodynamic state of these invertase plants, the monosaccharide composition, the pore size and the amount of free and bound acids present in the cell wall were measured. 

To characterize modifications in the cell wall composition of transgenic invertase plants we determined the distribution of neutral saccharides (Fig. 1). Obviously, the relative amounts of fucose and mannose were slightly reduced in leaf 6 of transgenic plants, whereas arabinose was increased. The other saccharides remained unchanged. 

Additionally, the content of free and total acids as a measure of the degree of pectin esterification was investigated (Fig. 2). The amounts of both free and total acids were increased in the transgenic plants. However, their ratios are not significantly affected when both plant lines are compared (Fig. 2). 

Shimizu et al. 2002). It was therefore shown that it is possible to produce transgenic plants with the capability of degrading chlorinated aromatic compounds, which are degraded with the formation of 3-chlorocatechol. 

Uchida E, T Ouchi, Y Suzuki, T Yoshida, H Habe, I Yamaguchi, T Omori, H Nojiri (2005) Secretion of bacterial xenobiotic-degrading enzymes from transgenic plants by an apoplastic expression system applicability for phytoremediation. Environ Sci Technol 39 7671-7677. 

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