BIOTECHNOLOGY & ITS APPLICATION

 Chapter-12 BIOTECHNOLOGY & ITS APPLICATION Biotechnology is making Genetically modified organisms-microbes, plants, animals for industrial production of Bio-Pharmaceuticals and other useful products. 
Applications – i) Diagnostic & therapeutic ii) Genetically modified crops iii) Waste treatment iv) Energy production v) Food processing vi) Bioremediation

Research areas-i) i) Providing the best catalyst in the form of improved organism usually a microbe or pure enzyme. (ii) Creating optimal conditions through engineering for a catalyst to act, and (iii) Downstream processing technologies to purify the protein/organic compound.

Three options that can be thought for increasing food production

(i) agro-chemical based agriculture ii) organic agriculture; and (iii) genetically engineered crop-based agriculture.

Application in agriculture: Genetically modified organisms (GMO)-Plants, bacteria, fungi, animals. whose genes are altered by manipulation. Transgenic crops(GMO) -Crops contain or express one or more useful foreign genes. Advantages -i) More tolerant to stresses (heat, cold, drought). ii) Pest resistants GM crops, reduce the use of Chemical pesticides. Eg- BT-Cotton iii) Reduced post harvest losses. Eg- Flavr savr tomato. iv) Enhance nutritional value of food. Eg- Golden Rice (Vitamin A enriched). v) Increased efficiency of mineral use.

PEST RESISTANT PLANTS: Bt- cotton -- The soil bacterium Bacillus thuringiensis produces crystal proteins called Cry proteins, that are toxic to larvae of insects like Tobacco budworm, armyworm, beetles and mosquitoes

The Cry proteins exist as inactive protoxins and get converted into active toxin when ingested by the insect, as the alkaline pH of gut solubilises the crystals.

- The activated toxin binds to the surface of epithelial cells of midgut and creates pores.

- This causes swelling and lysis of cells leading to the death of the insect (Larva).

- The genes (cry genes) encoding this protein are isolated from the bacterium and incorporated into several crop plants like cotton, tomato, corn, rice, soybean, etc.

- The proteins encoded by the following cry genes control the pest given against them.

= cry I Ac and cry II Ab control cotton bollworms.

= cry I Ab controls corn borer.

= cry III Ab controls colarado potato beetle.

= cry III Bb controls corn rootworm.

(b) Protection against Nematodes.

- A nematode Meloidogyne incognita infects tobacco plants and reduces their yield.

- The specific genes ( in the form of c DNA) from the parasite are introduced into the plant using Agrobacterium as the vector.

- The genes are introduced in such a way that both sense/coding RNA and antisense RNA (Complimentary to the sense/ coding RNA) are produced.

- Since these two RNAs are complementary, they from a double stranded RNA (ds RNA)

- This neutralizes the specific RNA of the nematode, by a process called RNA – interference.

As result the parasite cannot line in the transgenic host and the transgenic plant protected from the pest.

4. Application of biotechnology in medicine

• The rDNA technology has been used in the production of safe and more effective therapeutic drugs.

• The recombinant therapeutics do not induced unwanted immunological response, that are commonly observed with similar products isolated from non human resources.

• At present about thirty recombinant therapeutics have been approved fro human use, of which twelve are being marketed in India also.

Genetically engineered insulin (himulin).

- Human insulin consists of two short polypeptide chains : chain a and chain B , linked by disulphide bridges.

- Insulin is secreted as prohormone which has to be processed before it becomes a mature and functional hormone.

- the prohormone contains another polypeptide called C- peptide, which is removed during maturation.

- In 1983, Eli lilly, an American company, prepared two DNA sequences coding for chains A and B of human insulin and introduced them into plasmids of Escherichia coli to produce insulin.

- The two chains produced were extracted and combined by creating disulfide bridges.

(ii) Gene therapy

- In this method, genes are inserted into cells and tissues of an individual to correct certain hereditary diseases.

- It involves the delivery of a normal gene into the individual or embryo to replace the defective mutant allele of the gene.

- Viruses which attack the host and introduce their genetic material into host are all used as vectors.

- The first clinical gene therapy was given in 1990 to a four year old girl with adenosine deaminase (ADA) deficiency.

- ADA deficiency can be cured by bone marrow transplantation in some children but it is not completely curative.

- For gene therapy, lymphocytes were grown in a cultural and functional ADA. cDNA is then introduced into these lymphocytes.

- These lymphocytes are then transferred into the body of the patient ; the patient requires periodically infusion of such genetically engineered lymphocytes.

- If a functional gene is introduced into the bone marrow cells at early embryonic stage, it would be permanent cure.

(iii) Molecular diagnosis.

- Recombinant DNA molecules and techniques like PCR (Polymerase Chain Reaction) are used fro early diagnosis of disorders.

- Cloned gene when expressed to produce recombinant proteins, help developing sensitive diagnostic techniques like ELISA.

- The cloned genes are also used as ‘probes’ to detect the presence of complimentary DNA strand.

- A probe is a piece of single stranded DNA, that is tagged with a radioactive molecule and it is used ti find its complimentary DNA by hybridization.

- It is followed by detection of radioactivity by autoradiography.

- Presence of a normal or mutant gene can be detected using such a method.

PCR is used to detect HIV and to detect mutations in gene.

5. Transgenic Animals.

• Transgenic animals are those animals that have had their DNA manipulated to possesa and express a foreign gene.

• Transgenic animals are used in the following ways :

(i) Transgenic animals can be specifically deigned to allow the study of how genes are regulated and how they affect the normal functions of the body and its developments e.g. Information is obtained about the biological role of insulin like growth factor.

(ii) The transgenic animals are designed to increase our understanding of how genes contribute to the development of diseases ; they are made to serve as model for human diseases.

(iii) Transgenic animals that produce useful biological compounds can be created by introducing a portion of DNA that codes for that product from organism (s) e.g. alpha – 1, antitrypsin, a human protein used to treat emphysema. The first transgenic cow, Rosie, produced the human proteinenriched milk (2.4g/ltr); it also contained human alpha – lactalbumin, a more nutritionally balance product for human babies.

(iv) Transgenic mice are being developed fro use in testing the safety of vaccines. (e.g polio vaccine).

(v) Transgenic animals with more sensitivity to toxic substances are being developed to test the toxicity of drugs.

6. Ethical Issues .

• Genetic modification of organism can hane unpredictable/ undesirable effects when such organisms are introduced into the ecosystem.

• The modification and use of such organism fro public service has also resulted in problems with the granting of patents.

• Hence, the Indian Government has set up organization which are authorized to make

decisions regarding the validity of genetic modification and the safety of introducing

genetically modified organisms fro public services.

• One such organization is the Genetic Engineering approval committee (GEAC).

Biopiracy

• The industrialized/ developed nations are rich financially, bur poor in biodiversity and traditional knowledge , while the developing and underdeveloped countries are rich in bioresources and traditional knowledge.

• Some such developed countries use the bio resources and traditional knowledge of other countries without proper authorization and/ or compensation to the countries concerned (Biopiracy).

• Basmati rice grown in India is distinct for its unique flavor and aroma, but an American company got patent rights on Basmati through the US patent and trademark office; the new variety of Basmati has been developed by this company by crossing an Indian variety with semi-dwarf varieties.

Now some nations are developing laws to prevent such unauthorized exploitation of their bioresources and traditional knowledge