Biotechnology and its applications
Biotechnological applications in agriculture
Biotechnological applications in medicine Transgenic animals
Ethical issues
Biotechnology( DNA technology) as you learned within the previous chapter, is actually concerned with the production of biopharmaceuticals and biological substances on. an industrial scale using genetically modified microbes, fungi, plants and animals. Applications of biotechnology include therapeutics, diagnostics, genetically modified crops for agriculture, processed foods, bioremediation, waste treatment and energy production. The three critical areas of biotechnology research are:
Providing the simplest catalyst in the form of an improved organism usually a microbe or pure
Creating optimal conditions through engineering for catalyst action a
Post-processing technology for protein/organic material purification
Let us now learn how humans have used biotechnology to improve the quality of human life, especially within the areas of food production and health.
12.1 Biotechnological applications in agriculture
Let’s examine three options that can be considered for increasing food production
agriculture supported agrochemicals;
ecological agriculture; and
based on genetically modified crops
The revolution succeeded in tripling the food supply, but it had been not enough to feed the growing human population. The increased yields were partly thanks to the use of improved crop varieties, but mainly thanks to the use of better management practices and the use of agrochemicals (fertilizers and pesticides). However, agrochemicals are often too expensive for farmers within the developing world, and further yield increases in existing varieties aren’t possible through conventional breeding. Is there an alternate path that our understanding of genetics ( DNA technology)can point to so that farmers can get the maximum yield from their fields? Is there a way to minimize the use of fertilizers and chemicals to reduce their harmful effects on the environment? A possible solution is the use of genetically modified crops.
Plants, bacteria, fungi and animals whose genes are altered by manipulation are called genetically modified organisms (GMOs). GM plants are useful in many ways. Genetic modification has:
made crops more tolerant to abiotic stresses (cold, drought, salt, heat). reduced dependence on chemical pesticides (crops immune to pests). e.g., golden rice, i.e., enriched with vitamin ‘A’
In addition to these uses, GM is employed to create tailor-made plants that provide alternative resources for industry in the form of starches, fuels and pharmaceuticals.
Some of the applications of biotechnology ( DNA technology)in agriculture that you will study in detail are the production of plants that are resistant to pests, which could reduce the quantity of pesticides used. But toxin is produced by a bacterium called Bacillus thuringiensis (But for short). The Bt toxin gene was cloned from bacteria and expressed in plants to confer resistance to insects without the necessity for insecticides; he actually created a bio-pesticide. Examples are Bt cotton, Bt maize, rice, tomatoes, potatoes and soybeans, etc.
Bt cotton:
Some strains of Bacillus thuringiensis produce proteins that kill certain insects, like Lepidopterans (tobacco nematodes, armyworms), Coleopterans (beetles), and Diptera (flies, mosquitoes). B. thuringiensis forms protein crystals during a specific phase of its growth. These crystals contain a toxic insecticidal protein. Why does this toxin not kill Bacillus? after all, the Bt toxin protein exists as inactive prototoxins, but once an insect ingests the inactive toxin, it’s converted to the active form of the toxin by the alkaline pH of the gut, which dissolves the crystals. The activated toxin binds to the surface of the epithelial cells of the midgut and forms pores that cause swelling and cell lysis. ultimately causing the death of the insect.
Specific Bt toxin genes are isolated from Bacillus thuringiensis and incorporated into several crops such as cotton (Figure 12.1). Gene selection depends on the crop and target pest, as most Bt toxins are specific to the insect group. The toxin is encoded by a cryIAc gene called cry. There are variety of them, for instance the proteins encoded by the cryIAc and cryIIAb genes control cotton moths, the cryIAb protein controls the corn borer.
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