Biotechnology And Its Applications

Biotechnological Applications In Agriculture

Biotechnology, particularly recombinant DNA technology, has led to significant advancements in agriculture, aiming to increase crop yields, improve nutritional quality, and reduce reliance on chemical inputs like pesticides.

Potential Benefits of Biotechnological Applications in Agriculture:

Creation of GM (Genetically Modified) crops.
Increased crop yields.
Development of crops resistant to pests, diseases, and herbicides.
Development of crops tolerant to environmental stresses (drought, salinity, cold).
Improvement in nutritional value of food crops (Biofortification).
Reduced post-harvest losses.
Creation of designer plants for specific purposes.

Bt Cotton

Bt cotton is a genetically modified crop that expresses a toxin gene from the bacterium Bacillus thuringiensis (Bt). This provides the cotton plant with built-in resistance to certain insect pests, particularly lepidopteran insects like the cotton bollworm.

Mechanism:

The gene ($cry$ gene) coding for the Bt toxin is isolated from the bacterium and introduced into the cotton plant genome using genetic engineering techniques.

The plant cells then express this gene, producing the Bt toxin protein.

The Bt toxin is produced in an inactive protoxin form in the plant.

When insects with an alkaline gut ingest parts of the Bt cotton plant, the alkaline pH activates the protoxin, converting it into an active toxin.

The active toxin binds to receptors in the gut epithelial cells, creating pores and causing the cells to swell and lyse, leading to the death of the insect.

Bt cotton specifically targets certain insect pests and is not harmful to non-target insects or mammals because the toxin is activated only in the alkaline gut of the target insects, which is absent in mammals. Different Bt toxin genes ($cry$ genes) are effective against different insect groups (e.g., $cryIAc$ and $cryIIAb$ for cotton bollworms, $cryIAb$ for corn borer).

(Image shows a diagram illustrating a cotton plant with the Bt gene, an insect eating the plant, and the effect of the activated toxin in the insect's gut)

Pest Resistant Plants

Biotechnology can be used to develop resistance to other pests besides insects, such as nematodes.

Nematode Resistance (e.g., in Tobacco Plants):

A nematode called Meloidogyne incognitia infects the roots of tobacco plants, causing a reduction in yield.

Using RNA interference (RNAi) technology, plants can be made resistant to this nematode.

Mechanism: A gene that produces complementary sense and antisense RNA strands specific to the nematode's mRNA is introduced into the plant. These RNA strands form a double-stranded RNA (dsRNA) in the plant cells.

When the nematode feeds on the plant tissue, the dsRNA is ingested. In the nematode, the dsRNA is processed to produce small interfering RNAs (siRNAs).

These siRNAs bind to the specific nematode mRNA, leading to its silencing (degradation), preventing the synthesis of essential proteins for the nematode's survival.

The nematode cannot survive in the plant, and the plant becomes resistant.

(Image shows a diagram illustrating introducing a gene for complementary RNA into a plant, dsRNA forming in the plant, nematode eating plant, dsRNA processed to siRNA in nematode, siRNA binding to nematode mRNA, silencing nematode gene expression)

Development of pest-resistant plants reduces the need for chemical pesticides, which benefits farmers, the environment, and human health. However, concerns exist regarding the potential for pests to develop resistance to Bt crops over time.

Biotechnological Applications In Medicine

Biotechnology has significantly impacted the field of medicine, leading to the development of new diagnostic tools, therapeutic proteins, and gene-based therapies.

Genetically Engineered Insulin

Insulin is a hormone produced by the pancreas that regulates blood glucose levels. Diabetes Mellitus is a disease caused by the deficiency or ineffective use of insulin.

Historically, insulin for treating diabetes was obtained from the pancreas of slaughtered animals (cattle and pigs). However, animal insulin could cause allergies in some patients.
Using recombinant DNA technology, human insulin can now be produced on a large scale in bacteria.
Insulin consists of two polypeptide chains, A and B, linked by disulfide bonds. Proinsulin, the precursor form, contains an additional C peptide.
Eli Lilly, an American company, in 1983, produced human insulin (Humulin) using recombinant DNA technology.
Process: Genes for the A and B chains of human insulin were synthesised chemically and separately inserted into plasmids of *E. coli* bacteria. The bacteria produced the A and B chains separately. The A and B chains were then extracted and combined in vitro to form functional human insulin.

Diagram illustrating the production of human insulin (Humulin) using recombinant DNA technology in bacteria

*(Image shows a diagram illustrating the steps: obtaining genes for insulin A and B chains, inserting them into plasmids in E. coli, separate expression of A and B chains, extraction and combination to form functional insulin)*

Production of human insulin by genetic engineering provides a safe, pure, and abundant source of insulin for diabetic patients, reducing the risk of allergies associated with animal insulin.

Gene Therapy

Gene therapy is a method of treating genetic disorders by correcting a defective gene. It involves introducing a functional gene into a patient's cells to replace or compensate for a faulty gene.

Gene therapy was first performed in 1990 on a 4-year-old girl with Adenosine Deaminase (ADA) deficiency. ADA deficiency is a severe combined immunodeficiency (SCID) caused by a defective gene for the enzyme adenosine deaminase, which is essential for the immune system.
Treatment for ADA deficiency can involve enzyme replacement therapy (costly) or bone marrow transplant (if a suitable donor is available). Gene therapy was explored as a permanent cure.
Method for ADA deficiency: Lymphocytes (WBCs) are extracted from the patient's blood. A functional ADA gene is introduced into these lymphocytes using a viral vector. The genetically modified lymphocytes are then returned to the patient's body.
Initially, this was not a permanent cure as the lymphocytes are not immortal; periodically infusion of genetically engineered lymphocytes was required.
A potential permanent cure involves introducing the gene into bone marrow cells at an early embryonic stage.

Gene therapy is still largely experimental and faces significant challenges, but it holds great potential for treating a wide range of genetic diseases.

Molecular Diagnosis

Biotechnology provides advanced tools for the diagnosis of diseases at the molecular level, allowing for early and more accurate detection.

Traditional diagnostic methods (e.g., using symptoms, biochemical tests) may not be sensitive enough for early detection, especially when the pathogen load is very low.
Molecular diagnostic methods can detect the presence of a pathogen or a genetic abnormality at a very early stage.
Techniques include:
- PCR (Polymerase Chain Reaction): Amplifies DNA segments. Can detect the presence of very small amounts of pathogen DNA/RNA (e.g., in early HIV infection) or specific gene mutations (e.g., in genetic disorders or cancers).
- ELISA (Enzyme-Linked Immunosorbent Assay): Used to detect the presence of antibodies or antigens (proteins) related to a disease (e.g., for detecting HIV antibodies).
- DNA probes: Using single-stranded DNA or RNA sequences labelled with a radioactive molecule or fluorescent dye to hybridise with complementary DNA/RNA in a sample. Used to detect specific nucleotide sequences, such as viral or bacterial DNA/RNA in an infection, or specific gene mutations. Useful for diagnosing infections even before symptoms appear, or for identifying carriers of genetic disorders.

Molecular diagnosis is becoming increasingly important in modern healthcare for faster, more accurate diagnosis and personalised treatment approaches.

Transgenic Animals

Transgenic animals are animals whose genome has been altered by the introduction of foreign DNA (a gene from another species) through genetic engineering techniques. The introduced gene is called a transgene, and the animal carries and expresses this foreign gene.

Transgenic animals are created to study gene function, develop disease models, produce therapeutic proteins, and improve agricultural traits.

Applications Of Transgenic Animals

Transgenic animals have numerous applications in research, medicine, and agriculture:

Study of normal physiology and development: Transgenic animals with altered gene expression can help researchers understand how genes function and contribute to normal body development and function. Example: Introducing genes related to growth factors to study their effect on growth.
Study of diseases: Transgenic animals can serve as models for human diseases. By introducing genes that cause a specific disease in humans, researchers can study the development of the disease and test potential treatments. Example: Transgenic mice models for cancer, cystic fibrosis, Alzheimer's disease, rheumatoid arthritis.
Production of biological products: Transgenic animals can be engineered to produce valuable therapeutic proteins in their milk, blood, or other fluids. This is sometimes called 'molecular farming'.
- Example: Rosie, the first transgenic cow (1997), produced milk containing human alpha-lactalbumin, which is nutritionally more balanced for human babies than natural cow milk.
- Production of proteins like alpha-1-antitrypsin (for treating emphysema), tissue plasminogen activator (tPA - for dissolving blood clots), and factors VIII and IX (for treating haemophilia) in transgenic animals.
Vaccine safety testing: Transgenic mice are being developed to test the safety of vaccines before they are used on humans. Example: Transgenic mice susceptible to polio virus infection are used to test the safety of polio vaccines.
Chemical safety testing (Toxicity testing): Transgenic animals can be made more sensitive to toxic substances than non-transgenic animals. This allows for faster and more sensitive detection of the toxicity of chemicals (e.g., cosmetics, pesticides). Results are obtained in less time, reducing the need for extensive testing on large numbers of animals.
Improved agricultural traits: Though less common than transgenic plants, research is ongoing to develop transgenic animals with increased growth rate, improved feed efficiency, or resistance to diseases (e.g., transgenic fish with faster growth).

Diagram illustrating the creation of a transgenic animal (e.g., mouse) by injecting foreign DNA into zygote

*(Image shows a simplified diagram illustrating the process: obtaining a zygote, injecting foreign DNA into pronucleus, implanting the zygote into a surrogate mother, birth of transgenic offspring)*

Transgenic animals are powerful tools in scientific research and biotechnology, but their use also raises ethical concerns.

Ethical Issues

The advancements in biotechnology and genetic engineering, while offering tremendous potential benefits, also raise significant ethical questions and concerns. These concerns relate to the manipulation of living organisms, potential risks, and the implications for society and the environment.

Key Ethical Issues Related to Biotechnology:

Modification of organisms: Concerns about interfering with the natural genetic makeup of organisms and potential unintended consequences.
Use of animals: Ethical considerations regarding the welfare and use of animals in research and for producing transgenic animals.
Introduction of GM organisms: Potential risks to the environment (e.g., spread of transgenes to wild relatives, impact on non-target organisms, development of superweeds or resistant pests) and human health (e.g., potential allergens, toxicity).
Genetic privacy and discrimination: Concerns about the use of genetic information and potential for discrimination based on genetic predispositions.
Socio-economic impacts: Potential impact on traditional farming practices, accessibility of expensive biotechnological products.
Moral and religious concerns: Views on the sanctity of life and genetic manipulation.

Regulatory Aspects

To address the potential risks and ethical concerns associated with genetic modification and the use of genetically modified organisms (GMOs), many countries have established regulatory bodies and guidelines.

In India, the Government of India has set up organisations such as the Genetic Engineering Appraisal Committee (GEAC).
Functions of GEAC: Responsible for authorising the release of genetically modified organisms into the environment for research purposes or commercial use. It assesses the safety of GMOs for human health and the environment.
Regulatory frameworks are essential to ensure that biotechnological applications are developed and used responsibly and safely.

Patents And Biopiracy

Patents: Legal rights granted to an inventor or organisation that provide exclusive control over an invention for a limited period. In biotechnology, patents are often sought for genes, DNA sequences, recombinant DNA molecules, genetically modified organisms, biotechnological processes, and products. This raises ethical debates about patenting life forms and natural genetic resources.
Biopiracy: The unauthorised use of biological resources and/or traditional knowledge by individuals or organisations (often from developed countries) without proper compensation to the people or communities from which these resources and knowledge were obtained (often from developing countries).
Example: Patenting of products/processes based on traditional medicinal uses of plants like neem, turmeric, and basmati rice varieties without acknowledging or compensating the source communities and countries (India).
Biopiracy highlights the need for equitable sharing of benefits arising from the use of biological resources and traditional knowledge and the importance of protecting indigenous knowledge.

Addressing ethical issues and establishing effective regulatory frameworks are crucial for the responsible and sustainable development and application of biotechnology for the benefit of society.