Plants Transgenic crops

Plant cells can also be used to mass-produce human proteins. Com, soybean, and tobacco plants have been used in this way. The yield of protein from plants is generally higher than that from animals however, human cells link carbohydrates to some antibodies, and these molecules cannot yet be produced in plants. Transgenic crops that are harvested for food are far more common than those used to produce human proteins. 

There is also the additional concern of using transgenic plants and their environmental and genetic impact, and more specifically their effects in the human diet. Although a detailed discussion on transgenic crops is not within the scope of this review, it is worth mentioning a recent commentary on bioactives in transgenic plants by Finley (2005). 

Recombinant proteins with unique properties can potentially generate new markets and penetrate into existing markets if they can be supplied on a large scale. An ideal system would produce the safest biologically active material at the lowest cost, and would be used in combination with an inexpensive and simple purification process. So far, there have been several examples of the high-yield production of recombinant proteins in transgenic crop plants, mainly in the area of molecular medicines such as antibodies, enzymes and vaccines [45, 48-50]. Modern agricultural practices offer... 

Risk analysis has been proven to retain the flexibility necessary to make it a useful model system for addressing the countless issues that are found to be associated with plant-derived pharmaceuticals (Wolt and Peterson, 2000). Over the past few years, a great deal of information and experience has steadily accumulated with respect to risk analysis of pharmaceuticals that are currently produced in bacterial and aifimal cell bioreactor systems. Risk analysis has also been performed on transgenic crops used for food production as well as for other applications. As a result, elements from each of these disciplines can be incorporated into the design of optimal production and testing policies and practices. Risk analysis has been employed to cover a series of important issues regarding the large-scale manufacture of plant-made biopharmaceuticals, and will continue to present serious issues for researchers in the academic, corporate, and public health arenas to address (Miele, 1997 Ciliberti and Molinelli, 2005). 

The potential of flow of plant-made biopharmaceuticals into the human food chain remains. For example, plant-derived pharmaceuticals could cross-contaminate foodstuffs by spontaneous growth of transgenic crops in areas outside the intended field, or by pollen flow between some plants such as corn. It has been suggested that plant-derived biopharmaceuticals should be generated in nonfood crops, such as tobacco. However, food crops produce the greatest opportuitities for efficient production since they are among the most well-studied of crops. This continues to make them more feasible for edible vaccine production. 

As these toxins are proteins it is possible to isolate the genes that code for them and use these genes to transform crop plants and thereby render them insecticidal. This is discussed briefly under Transgenic Crops (Section 6). 

WoTldwide. about 70 million acres of farmland are cultivated with transgenic crops. As a result, about one-third of the world com harvest and more than one-half of the world soybean harvest now come from genetically engineered plants. If you think you have never ingested transgenic foods, think again. 

This review has succinctly summarized what is presently known of nonprotein and protein protease inhibitors from plants. The affinities of the non-protein inhibitors for particular proteases are generally much lower than those of plant protease inhibitor proteins (PIPs). Nevertheless the non-protein protease inhibitors may provide structure/activity starting points for development of pharmaceutically useful compounds of much higher affinity. The plant PIP literature has been comprehensively surveyed in this review. However electronic databases such as EMBL and SWISSPROT contain further accessible plant PIP sequences [581]. The array of potent plant PIPs reflects the co-evolution of plant defensive proteins and insect resistance [582]. Potent, stable, protease inhibitor proteins have potential transgenic crop agriculture applications as well as potential chemotherapeutic applications. 

United States and European pharmaceutical and chemical companies have taken the lead in biotechnology, frequently by purchasing plant breeders and growers of planting seeds. Various producers offer transgenic crop seeds resistant to several herbicides. The Monsanto Company (St. Louis, MO) has often been... 

The advantage for the farmer is that he needs only one product, instead of several different selective (and more expensive) herbicides. Roundup ready soybeans were launched in 1996 and today 50 percent of the soybean crop in the United States is derived from roundup ready seeds. Other glyphosate-resistant transgenic crops introduced by Monsanto are maize and oil seed rape. Competing companies also developed herbicide-resistant plants or plants genetically modified to be protected against certain pests, but none has achieved a commercial breakthrough, mainly because of political reasons. 

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