Biotechnological Applications In Agriculture

Biotechnology offers several approaches to increase food production, including agrochemical-based agriculture, organic agriculture, and genetically engineered (GM) crops. While the Green Revolution significantly increased yields, growing populations necessitate further advancements. Traditional breeding methods are often slow, leading to the development of techniques like tissue culture.

Tissue Culture: This technique allows regeneration of whole plants from plant parts (explants) in sterile nutrient media containing carbon sources (sucrose), inorganic salts, vitamins, amino acids, and growth regulators. The ability of a plant cell to regenerate into a whole plant is called totipotency. Large-scale propagation of genetically identical plants (somaclones) can be achieved through micro-propagation, used commercially for crops like tomato, banana, and apple. Tissue culture also enables the recovery of virus-free plants by culturing meristems, as meristematic tissues are usually virus-free.

Somatic Hybridization: This involves fusing protoplasts (plant cells with cell walls removed) from different varieties to create hybrid cells, which can then be regenerated into new plants. These somatic hybrids combine desirable traits from parent plants. An example is the "pomato" (tomato fused with potato), though not always commercially viable.

Genetically Modified Organisms (GMOs): Plants, bacteria, fungi, and animals whose genes have been altered through manipulation are called GMOs. GM crops offer several advantages:

• Increased tolerance to abiotic stresses (cold, drought, salt, heat).
• Reduced reliance on chemical pesticides (pest-resistant crops).
• Reduced post-harvest losses.
• Enhanced mineral uptake efficiency, preventing soil exhaustion.
• Improved nutritional value (e.g., Golden Rice, enriched with Vitamin A).
• Production of industrial resources like starches and pharmaceuticals.

Pest-Resistant Plants: Bt toxin, produced by Bacillus thuringiensis, is an insecticidal protein. The gene encoding this toxin (cry gene) has been introduced into crop plants like cotton (Bt cotton) and corn. These plants produce inactive protoxins, which become active in the insect gut, forming pores and killing the larvae. This reduces the need for chemical insecticides.

RNA Interference (RNAi) for Pest Resistance: This technology silences specific genes in pests by using complementary double-stranded RNA (dsRNA). By introducing nematode-specific genes into plants, which produce complementary sense and anti-sense RNAs, the specific mRNA of the nematode is silenced, preventing its survival and protecting the plant from infestation. This method has been successfully used against Meloidogyne incognitia in tobacco.

Biotechnological Applications In Medicine

Biotechnology has revolutionized healthcare by enabling the mass production of safe and effective therapeutics, including recombinant pharmaceuticals. These products, being identical to human proteins, minimize unwanted immunological responses and risks of infection.

Genetically Engineered Insulin

Insulin, a hormone regulating blood glucose, was traditionally extracted from animal pancreases, often causing allergic reactions. Recombinant DNA technology allows for the production of human insulin. In 1983, Eli Lilly produced human insulin by isolating DNA sequences for the A and B chains, inserting them into E. coli plasmids, and producing the chains separately. These chains were then extracted and combined to form functional human insulin. Human insulin is synthesized as a pro-hormone containing a C-peptide, which is removed during maturation.

Gene Therapy

Gene therapy aims to correct genetic disorders by delivering normal genes into a patient's cells or embryos to replace or compensate for defective genes. The first successful gene therapy was administered in 1990 to a four-year-old girl with Adenosine Deaminase (ADA) deficiency. Functional ADA cDNA was introduced into her lymphocytes using a retroviral vector, and these modified cells were returned to her body. While this provides temporary relief, permanent cure requires introducing the functional gene into early embryonic stem cells.

Molecular Diagnosis

Early and accurate diagnosis of diseases is crucial for effective treatment. Techniques based on recombinant DNA technology, PCR, and ELISA have significantly improved diagnostic capabilities.

• PCR (Polymerase Chain Reaction): Amplifies even minute amounts of nucleic acids (DNA or RNA), enabling early detection of pathogens like HIV and mutations in genes associated with cancer or genetic disorders, even before symptoms appear.
• Probes: Single-stranded DNA or RNA tagged with a radioactive molecule can hybridize to complementary DNA sequences in cell clones. This allows for the detection of specific genes, including mutated ones (which won't hybridize), facilitating diagnosis.
• ELISA (Enzyme-Linked Immuno-Sorbent Assay): Based on antigen-antibody interactions, it detects infections by identifying either the pathogen's antigens or the antibodies produced against it in the patient's body.

Transgenic Animals

Transgenic animals are animals whose DNA has been manipulated to contain and express an extra foreign gene. Over 95% of existing transgenic animals are mice, but transgenic rats, rabbits, pigs, sheep, cows, and fish have also been created. They are produced for several key purposes:

• Studying Physiology and Development: Transgenic animals help researchers understand gene regulation and the roles of specific genes in normal body functions and development (e.g., studying growth factors like insulin-like growth factor).
• Studying Diseases: They serve as models for human diseases (e.g., cancer, cystic fibrosis, Alzheimer's) to investigate disease mechanisms and test new treatments.
• Producing Biological Products: Transgenic animals can be engineered to produce valuable human proteins for therapeutic purposes, such as α-1-antitrypsin (to treat emphysema), or nutritionally improved milk, like Rosie the cow producing human α-lactalbumin.
• Vaccine Safety Testing: Transgenic mice are used to test the safety of vaccines, potentially replacing animal testing in some cases.
• Toxicity Testing: Transgenic animals with genes making them more sensitive to toxins allow for faster and more accurate safety testing of chemicals and drugs.

Ethical Issues

The manipulation of living organisms raises significant ethical questions regarding the morality of such activities and their potential impact on ecosystems. The Indian government addresses these concerns through regulatory bodies like the GEAC (Genetic Engineering Approval Committee), which oversees GM research and the safety of introducing GMOs into public use.

Biopiracy and Patents: There is growing public concern about multinational companies obtaining patents for products and technologies derived from the bio-resources and traditional knowledge of specific regions or countries without proper authorization or compensation. For example, a US company patented Basmati rice derived from Indian varieties, potentially restricting the rights of Indian farmers. Similar attempts have been made to patent traditional herbal medicines like turmeric and neem. Vigilance and legal measures are necessary to protect national bio-resources and traditional knowledge.

Biopiracy refers to the unauthorized exploitation of bio-resources and traditional knowledge by companies, often from developed nations, exploiting the biodiversity-rich but financially less-equipped developing nations. Laws are being developed globally to prevent such exploitation and ensure equitable benefit sharing.

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