Tiêu đề BIOTECHNOLOGY & ITS APPLICATIONS.pdf ✅

 Digital www.allendigital.in [ 43 ] 1. Introduction : • Biotechnology, essentially deals with industrial scale production of biopharmaceuticals and biologicals using genetically modified microbes, fungi, plants and animals. • The applications of biotechnology include therapeutics, diagnostics, genetically modified crops for agriculture, processed food, bioremediation, waste treatment, and energy production. Three critical research areas of biotechnology are: (a) Providing the best catalyst in the form of improved organism usually a microbe or pure enzyme. (b) Creating optimal conditions through engineering for a catalyst to act, and (c) Downstream processing technologies to purify the protein/organic compound. 2. Biotechnological Application in Agriculture : Let us take a look at the three options that can be thought for increasing food production. Increased Food Production : I. Agro-chemical based agriculture : Based on chemical fertilizers and chemical pesticides. Results into increased production but quality decreases. II. Organic farming/agriculture : Chemical free agriculture. Based on biofertilizers and biopesticides. III. Genetically engineered crop-based agriculture : For this, desired gene is transferred in plant. Now these plants are called as Genetic Modified (GM) / Transgenic plant/Tailor- made plants. • The Green Revolution succeeded in tripling the food supply but yet it was not enough to feed the growing human population. • Increased yields have partly been due to the use of improved crop varieties, but mainly due to the use of better management practices and use of agrochemicals (fertilisers and pesticides). • However, for farmers in the developing world, agrochemicals are often too expensive, and further increases in yield with existing varieties are not possible using conventional breeding. • Is there any alternative path that our understanding of genetics can show so that farmers may obtain maximum yield from their fields? Is there a way to minimise the use of fertilisers and chemicals so that their harmful effects on the environment are reduced? Use of genetically modified crops is a possible solution. • Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). In addition to these uses, GM has been used to create tailor-made plants to supply alternative resources to industries, in the form of starches, fuels and pharmaceuticals. Biotechnology and its 03 Applications

Biotechnology and its Applications  Digital www.allendigital.in [ 45 ] • The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis and eventually cause death of the insect. • Bacillus thuringiensis, produces crystal [Cry] protein. This Cry protein is toxic to larvae of certain insects. Each Cry protein is toxic to a different group of insects. • The gene encoding Cry protein is called "cry gene". This cry gene is isolated and transferred into several crops. • However, gene symbol italics, e.g. cry. The first letter of the protein symbol, on the other hand, is always capital and the symbol is always written in roman letters. e.g. Cry. Bt cotton : • Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton. • The choice of genes depends upon the crop and the targeted pest, as most Bt toxins are insect-group specific. • The toxin is coded by a gene cryIAc named cry. There are a number of them, for example, the proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms, that of cryIAb controls corn borer. (B) Nematode (Pest) Resistant Plants: • Several nematodes parasitise a wide variety of plants and animals including human beings. A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield. • A novel strategy was adopted to prevent this infestation which was based on the process of RNA interference (RNAi). RNAi takes place in all eukaryotic organisms as a method of cellular defense. Inactive toxin Crystalline protein Midgut epithelial cells Midgut epithelial cells Active toxin Alkaline pH Dissolving Cotton boll : (a) destroyed by bollworms; (b) a fully mature cotton boll
NEET : Biology [ 46 ] www.allendigital.in  Digital • This method involves silencing of a specific mRNA due to a complementary dsRNA molecule that binds to and prevents translation of the mRNA (silencing). • The source of this complementary RNA could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) that replicate via an RNA intermediate. • Using Agrobacterium vectors, nematode- specific genes were introduced into the host plant. The introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. • These two RNA’s being complementary to each other formed a double stranded (dsRNA) that initiated RNAi and thus, silenced the specific mRNA of the nematode. The consequence was that the parasite could not survive in a transgenic host expressing specific interfering RNA. The transgenic plant therefore got itself protected from the parasite. 3. Biotechnological Applications in Medicine : • The recombinant DNA technological processes have made immense impact in the area of healthcare by enabling mass production of safe and more effective therapeutic drugs. Further, the recombinant therapeutics do not induce unwanted immunological responses as is common in case of similar products isolated from non-human sources. At present, about 30 recombinant therapeutics have been approved for human-use the world over. In India, 12 of these are presently being marketed. T P Sense Antisense Sense Antisense ( ds RNA) P T T P Cut by Dicer (RNA) (RNA) Gene transferred in plant P T Artificial target gene of nematode Si – RNA (Small interfering) Nematode Root cell P T Target gene RNA Protein Host plant-generated dsRNA triggers protection against nematode infestation : (a) Roots of a typical control plants; (b) transgenic plant roots 5 days after deliberate infection of nematode but protected through novel mechanism.