Unit 4: Biotechnology and Its Applications - Chapter 2: Applications

4.2 Applications of Biotechnology

Biotechnology has a wide range of applications in various fields, including health, agriculture, and environmental management.

Health Applications

1. Therapeutic Proteins (e.g., Insulin Production):

   • Human Insulin: Traditionally, insulin was extracted from the pancreas of slaughtered cattle and pigs, which often caused allergic reactions in some patients.
   • Recombinant DNA Technology: In 1983, Eli Lilly an American company, prepared two DNA sequences corresponding to the A and B chains of human insulin and introduced them into plasmids of E. coli to produce insulin chains. These chains were then extracted and combined by creating disulfide bonds to form human insulin (Humulin).
   • This recombinant insulin is identical to human insulin and does not cause allergic reactions.

2. Vaccines (Recombinant Vaccines):

   • Biotechnology has revolutionized vaccine production, leading to safer and more effective vaccines.
   • Recombinant Vaccines: Involve inserting genes encoding specific antigens (proteins that trigger an immune response) from pathogens into a harmless vector (e.g., yeast, bacteria, or viruses). The host then produces the antigen, which can be purified and used as a vaccine.
   • Example: Hepatitis B vaccine, produced using recombinant DNA technology in yeast.
   • Advantages: Safer (no risk of infection from the pathogen), can be produced in large quantities, and are often more stable.

3. Gene Therapy:

   • A technique used to correct a gene defect that results in a disease.
   • Involves the introduction of a functional gene into a patient's cells to replace a defective one.
   • First Clinical Gene Therapy (1990): Performed on a 4-year-old girl with Adenosine Deaminase (ADA) deficiency, which causes Severe Combined Immunodeficiency (SCID).
     • Process: Lymphocytes from the patient's blood are grown in a culture. A functional ADA cDNA (using a retroviral vector) is introduced into these lymphocytes, which are then returned to the patient. This requires periodic infusion of such genetically engineered lymphocytes.
     • Permanent Cure: For a permanent cure, the gene isolated from marrow cells producing ADA is introduced into cells at an early embryonic stage.

4. Stem Cell Technology:

   • Stem Cells: Undifferentiated cells that have the ability to self-renew and differentiate into various specialized cell types.
   • Applications: Regenerative medicine (repairing damaged tissues/organs), drug discovery, disease modeling.
   • Types: Embryonic stem cells (pluripotent), adult stem cells (multipotent), induced pluripotent stem cells (iPSCs).

5. Molecular Diagnosis:

   • Biotechnology provides powerful tools for early and accurate diagnosis of diseases.
   • Conventional methods (e.g., serum and urine analysis) are often not sensitive enough to detect very low concentrations of pathogens or toxins in the early stages of disease.
   • Techniques:
     • PCR (Polymerase Chain Reaction): Used to detect very low concentrations of bacteria or viruses (e.g., HIV in AIDS patients, mutations in cancer patients, genetic disorders) by amplifying their nucleic acids.
     • ELISA (Enzyme-Linked Immunosorbent Assay): Based on the principle of antigen-antibody interaction. Used to detect the presence of antigens (proteins of pathogen) or antibodies (synthesized against pathogen) in a patient's serum (e.g., for AIDS, typhoid).

Agricultural Applications

1. Genetically Modified (GM) Crops:

   • Plants whose genes have been altered by genetic engineering to introduce new traits.
   • Advantages:
     • More tolerant to abiotic stresses (cold, drought, salt, heat).
     • Reduced reliance on chemical pesticides (pest-resistant crops).
     • Reduced post-harvest losses.
     • Increased efficiency of mineral usage by plants.
     • Enhanced nutritional value of food.
   • Pest-Resistant Crops:
     • Bt Cotton: Some bacteria (Bacillus thuringiensis - Bt) produce proteins that are toxic to certain insects (e.g., lepidopterans, coleopterans, dipterans). The gene encoding this protein (e.g., cryIAc, cryIIAb) is isolated from Bt and incorporated into crop plants like cotton. The plant then produces the toxin, making it resistant to insect pests.
     • RNA interference (RNAi): A method used to develop pest-resistant plants. For example, in tobacco plants, a nematode (Meloidogyne incognita) infects the roots. Using Agrobacterium vectors, nematode-specific genes are introduced into the host plant. These genes produce double-stranded RNA (dsRNA) that silences the specific mRNA of the nematode, leading to its death.

2. Biofortification (e.g., Golden Rice):

   • Breeding crops with higher levels of vitamins, minerals, or proteins.
   • Golden Rice: A genetically modified variety of rice that contains genes for beta-carotene (a precursor of Vitamin A). It aims to combat Vitamin A deficiency, especially in developing countries where rice is a staple food.

Transgenic Animals

Transgenic animals are animals that have had their DNA manipulated to possess and express an extra (foreign) gene.

• Purpose:
  • Study of Gene Regulation and Development: To understand how genes contribute to the development of disease.
  • Study of Diseases: To serve as models for human diseases (e.g., cancer, cystic fibrosis, rheumatoid arthritis, Alzheimer's).
  • Biological Products: Production of useful biological products.
    • Example: Transgenic cow Rosie (1997) produced human alpha-lactalbumin enriched milk (2.4 grams of protein per liter), which was nutritionally more balanced for human babies than natural cow milk.
    • Alpha-1-antitrypsin: Used to treat emphysema.
  • Vaccine Safety Testing: Transgenic mice are used to test the safety of vaccines (e.g., polio vaccine) before they are used on humans.
  • Chemical Safety Testing: Transgenic animals (e.g., mice) are made more sensitive to toxic substances than non-transgenic animals, allowing for quicker and more efficient testing of chemical toxicity.

Biosafety Issues, GEAC

Biosafety Issues:

• The use of genetically modified organisms (GMOs) raises several ethical and safety concerns:
  • Ecological Risks: Potential for gene flow from GM crops to wild relatives, leading to superweeds; impact on non-target organisms (e.g., beneficial insects); loss of biodiversity.
  • Health Risks: Potential for allergenicity or toxicity in GM foods; development of antibiotic resistance in pathogens if antibiotic resistance markers are used in GMOs.
  • Ethical Concerns: Moral and religious objections to genetic manipulation; concerns about the long-term effects on human health and the environment.

GEAC (Genetic Engineering Appraisal Committee):

• An organization set up by the Indian government.
• Responsible for making decisions regarding the validity of GM research and the safety of introducing GM organisms for public services.

Biopiracy and Biopatents

Biopiracy:

• The unauthorized appropriation of traditional knowledge and genetic resources from indigenous communities or countries without proper compensation or permission.
• Often involves the patenting of traditional knowledge or genetic resources by corporations or researchers from developed countries, without acknowledging the original innovators.

Biopatents:

• Patents granted for biological entities and products derived from them.
• Can be granted for:
  • Strains of microorganisms.
  • Cell lines.
  • Genetically modified organisms.
  • DNA sequences.
  • Biotechnological processes.

Examples of Biopiracy:

• Turmeric: A U.S. patent was granted for the wound-healing properties of turmeric, a traditional Indian medicine. The patent was later revoked after India provided evidence of its traditional use.
• Basmati Rice: A U.S. company (RiceTec) was granted a patent for a new variety of Basmati rice, which was essentially a hybrid of Indian Basmati and American long-grain rice. This caused outrage in India, as Basmati is a traditional Indian rice variety. The patent was later narrowed down.

These cases highlight the need for international agreements and national laws to protect traditional knowledge and prevent biopiracy, ensuring equitable sharing of benefits arising from the use of genetic resources.