Biotechnology has varied applications, some of which include :-
- Genetically modified crops for agriculture
- Processed food
- Waste treatment
- Energy production
There are critical research areas of biotechnology
- Providing best catalyst as improved organism , usually a microbe or pure enzyme .
- Creating optimal conditions by engineering for a catalyst to act .
- Downstream processing technologies to purify the proteins / organic compound.
Biotechnological Applications In Agriculture
Food production can be increased by applying biotechnology by the following ways :
- Agrochemical-based agriculture.
- Organic agriculture
- Genetically engineered crop-based agriculture.
The green revolution succeeded in increasing food supply because of
- Use of improved crop varieties.
- Use of improved crop varieties.
- Use of agrochemicals ( fertilisers and pesticides)
Agrochemicals are expensive for farmers in developing countries and also have harmful effects on environment. Therefore genetically modified crops were developed.
Genetically Modified Organism (GMOs)
Plants, bacteria, fungi and animals whose genes have been altered by manipulation.
. Genetic modification of crops have resulted in
- Increased tolerance against abiotic stresses ( cold, drought,salf, heat)
- Reduced reliance on chemical pesticides ( pest-resistant crops).
- Reduced post-harvest losses.
- Increased efficiency of minerals used by plants (this prevents early exhaustion of fertility of soil).
- Enhanced nutritional value of food,e.g., vitamin ‘A’ enriched rice ( golden rice )
- Creation of tailor-made plants to supply-alternative resources such as starches, fuels and pharmaceuticals to industries.
- Some strains of Bacillus thuringiensis produce crystals during a particular phase of their growth.
- The crystals contain a toxic insecticidal protein that kill certain insects such as lepidopterans ( tobacco budworm,armyworm), coleopterans (beetles) and dipterans ( flies, mosquitoes).
- The toxin does not kill the bacillus because the Bt toxin protein exists as inactive protoxins but once the insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilize the crystals.
- The activated toxin binds to the surface of mid gut epithelial cells and create pores that cause cell swelling and lysis and cause death of the insect.
- The toxin is coded by a gene named cry.
- There are number of genes acting against the insects, for example, the proteins encoded by the genes cryLAc and cryllab control the cotton bollworms, that of crylab controls corn borer.
- Specific bt toxin genes were isolated from Bacillus thuringiensis based on the crop and the targeted pest which is then incorporated into the several crop plants.
Pest Resistant Plants -
- A nematode Meloidogyne incognita infects the roots of tobacco plants which reduces the production of tobacco.
- It can be prevented by using RNA interference (RNAi) process which is checked by silencing of specific mRNA due to complements dsRNA.
- DsRNA binds and prevent translation of the mRNA (silencing)
- By using agrobacterium vectors, nematode -specific genes were introduced into the host plants which produce both sense and antisense RNA in the host cells.
- These two RNAs are complementary to each other and form a double – stranded RNA (dsRNA) that initiates RNAi and silences the specific mRNA of the nematode.
- The parasites cannot survive in the transgenic host,
- So protects the plants from pests.
Biotechnological Applications In Medicine
- The recombinant DNA technology is used for production of therapeutic drugs which are safe and effective.
- It avoids unwanted immunological responses, commonly observed with similar products isolated from non- human resources
- About thirty recombinant therapeutics have been approved for human use in the world including india.
Genetically Engineered Insulin
- Insulin contains two short polypeptide chains – chain A and chain B linked by disulphide bridges.
- In mammals, insulin is synthesized as a pro – hormone ( that needs to be processed to become mature and functional hormone ). It contains an extra stretch called C peptide.
- C peptide is absent in mature insulin and is removed during maturation into insulin.
- Earlier ,insulin was extracted from pancreas of slaughtered cattle and pigs but some patients began developing allergies.
- Production of insulin by rDNA techniques was achieved by an American company,Eli lilly , in 1983. It prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of coli for production.
- The A and B chains produced, were separated, extracted and combined. By creating disulfide bonds to form human insulin.
Gene Therapy -
Gene therapy is a collection of methods that allows correction of gene defects, diagnosed in a child or embryo.
By insertion of normal genes,the defective mutant allele of the genes of the genes are replaced and non – functional gene is compensated.
For the first time in 1990 , M. blease and W.F. Andrescose of National institute of Health, attempted gene therapy on a 4 year old girl with adenosine deaminase (ADA) deficiency.
ADA is caused due to deletion of gene for adenosine deaminase.
In some cases, it can be cured by bone marrow transplantation and enzyme replacement therapy but it is not fully curative.
Lymphocytes from the patient’s blood were grown in a culture and functional ADA, cDNA was introduced in these lymphocytes using a retroviral vector.
The lymphocytes were transferred into the patient’s body, periodic infusion of such genetically engineered lymphocytes is done because these cells are mortal.
For permanent cure, gene isolated from the bone marrow cells producing ADA , at early embryonic stage can be a possible cure.
Other diseases like cystic fibrosis, haemophilia, cancer, parkinson’s etc.are also treated by gene therapy.
Early detection of disease is not possible by conventional diagnosis methods.
Some techniques used for early diagnosis are :-
Polymerase chain reaction –
- Low concentration of the pathogen in the body does not allow its detection.
- The nuclear acid of the pathogen ( bacteria or virus ) is amplified by PCR for its detection.
- It is being used for detection of HIV in suspended AIDS patients and genetic mutations in suspected cancer patients.
Recombinant DNA technology
- A single stranded DNA or RNA tagged with a radioactive molecule is called probe.
- In the method, a probe is allowed to hybridise to its complementary DNA in the clone of cells.
- The cells are then detected by autoradiography.
- The cells with mutated gene will not be observed on the photographic film because the probe was not complementary to the mutated gene.
Enzyme linked immune – sorbent assay (ELISA) –
- It is based on the principle of antigen- antibody interaction.
- Either the presence of antigens ( proteins , glycoprotein , etc. ) are detected or the antibodies produced against the pathogens are detected.
Stem cell technology
- Stem cells are undifferentiated biological cells. These can differentiate into specialized cells and can divide to produce more stems cells.
- Stem cells are found in multicellular organisms.
- Adult stem cells are used in medical therapies, for example, in bone marrow transplantation.
- Stem cells can also be taken from umbilical cord just after birth.
Transgenic Animals -
Animals whose DNA is manipulated to possess and express an extra gene are known as transgenic animals. Transgenic rats, rabbits, pigs, sheep, and cows have been produced.
Following are the common reasons for developing transgenic animals :-
Study of normal physiology and development
- Useful to study gene regulation, their effect on the normal functions of the body and its development.
- For example, study of complex growth factors like insulin- like growth factor.
Study of disease
- Study of genes which are responsible for disease in human and their treatment.
- Transgenic models have been developed for many human disease like cancer, fibrosis, rheumatoid arthritis and Alzheimer’s disease.
- Useful biological products can be produced by introducing, into transgenic animals, the portion of DNA ( or genes) which codes.
- For example, human protein a-1 antitrypsin is used to treat emphysema.
- In 1997, the first transgenic cow , Rosie, produced human protein- enriched milk (2.4 g/L).
- The milk contained the human alpha – lactalbumin and was more nutritionally balanced for human babies that natural cow milk.
- Transgenic mice are developed to test safety of vaccines, before being used on humans.
- For example, polio vaccines.
Ethical Issues -
- Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem. The Indian government has set up organizations such as GEAC ( Genetic Engineering Approval Committee ), to make decisions regarding the validity of GM research and the safety of introducing GM -organisms for public service.
- The modification/usage of living organisms for public services has also created problems with patents granted for the same.
- Parents is the right granted by the government to a producer to prevent other from using his product.
- An American company got patents right on basmati rice but the variety of basmati had actually been derived from Indian farmer’s varieties.
- Several attempts have also been made to patent uses, products and processes based on Indian traditional herbal medicines. Example – turmeric, neem.
- Biopiracy is the term used to refer to the use of bio-resources by multinational companies and other organization without proper authorization from the countries and people concerned without compensatory payment.
- Some nations are developed laws to prevent such unauthorized exploitation of their bio-resources and traditional knowledge.
- Biopiracy is defined as the use of bioresources by multinational companies and other organisations without proper authorization from the countries and concerned people, without compensatory payment.
- Generally, financially rich nations are poor in biodiversity and traditional knowledge, with developed and under-depeloped nations are rich in biodiversity and traditional knowledge,related to bioresources.
- Traditional knowledge related to bioresources can be exploited to develop modern applications and are used to save time, efforts and expenditure during their commercialization.
- Some nations are developing laws, to prevent such unauthorized exploitation of their bioresources and traditional knowledge.
- A patents is set of exclusive rights by a state to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention,
- Patents satisfy three criteria:- novelty , nonobviousness utility