Biotechnology and Its Applications

Learning outcomes:

1. Understand key applications of biotechnology in agriculture and medicine.
2. Explore the role of transgenic animals in research and medicine.
3. Comprehend ethical issues associated with genetic manipulation and biopiracy.
4. Learn about gene therapy, molecular diagnosis, and pest-resistant crops.

Biotechnological Applications in Agriculture

Biotechnology has significantly impacted agriculture by offering advanced methods to enhance crop yield and resilience. The traditional Green Revolution increased food supply but was insufficient to meet the growing demands. Biotechnological innovations, particularly the development of genetically modified organisms (GMOs), have become vital in this area. Three main strategies to improve food production have been considered:

1. Agro-chemical based agriculture: This method relies heavily on fertilizers and pesticides to boost crop yields, but it presents sustainability challenges, particularly in developing nations, where such chemicals are expensive and can have harmful environmental effects.
2. Organic agriculture: While sustainable, organic farming often results in lower yields, which can limit its capacity to meet the demands of a growing population.
3. Genetically engineered crops: This option offers the potential to significantly improve yields and reduce reliance on chemical inputs through genetic modification.

Tissue Culture and Micro-propagation
Tissue culture technology emerged in response to the limitations of conventional breeding methods. In the 1950s, scientists discovered that entire plants could be regenerated from explant cells in a sterile, nutrient-rich environment. This concept, known as totipotency, allows for the propagation of large numbers of plants in a short period. Plants produced through this method are genetically identical, known as somaclones. Some important applications include:

1. Micro-propagation: This method has been employed commercially for producing plants like tomato, banana, and apple.
2. Recovery of healthy plants: Virus-infected plants can be regenerated from virus-free meristems using tissue culture techniques, producing healthy plants, such as sugarcane and potato.
3. Somatic hybridization: This process involves the fusion of protoplasts from different plant varieties, creating hybrids with desirable traits. For instance, hybrid protoplasts from tomato and potato plants were fused to form a new plant, although commercial utilization remained limited.

Genetically Modified Organisms (GMOs)
Genetic modification in agriculture has several advantages, including improving plant resistance to abiotic stresses and enhancing their nutritional value. For instance, golden rice is genetically modified to contain higher levels of Vitamin A. GM plants can:

1. Increase tolerance to abiotic stresses like drought, heat, and cold.
2. Reduce reliance on chemical pesticides, as GM plants can be engineered to resist pests.
3. Reduce post-harvest losses through genetic modifications that extend the shelf life of crops.
4. Enhance mineral uptake, leading to improved soil fertility management.
5. Tailor crops for industrial use, such as producing starches, fuels, and pharmaceuticals.

Pest-Resistant Crops
Bt toxin, derived from the bacterium Bacillus thuringiensis, has been genetically introduced into several crops, enabling them to produce insecticidal proteins. This innovation has led to the development of crops like Bt cotton and Bt corn that are resistant to certain pests. The process involves:

1. Bt toxin protein production: Certain strains of B. thuringiensis produce proteins that target specific insect species, such as tobacco budworm and corn borer.
2. Toxin activation: When ingested by insects, the inactive Bt toxin becomes activated in their alkaline gut, causing cell lysis and ultimately the insect’s death.

RNA Interference (RNAi) Technology
RNAi is another advanced technique used to create pest-resistant plants. This method silences specific genes in pests by introducing double-stranded RNA (dsRNA) into plants. For instance:

1. Nematode resistance: Meloidegyne incognitia, a nematode that infects tobacco plants, can be controlled by introducing nematode-specific genes into the host plant. This method blocks the nematode’s mRNA, preventing it from replicating and damaging the plant.

Biotechnological Applications in Medicine

Biotechnology has transformed the medical field, particularly through the development of recombinant DNA technologies that enable mass production of therapeutic drugs. These drugs, derived from genetically modified organisms, are safer and more effective than their non-human counterparts, reducing the risk of immunological responses. Some key applications include:

Genetically Engineered Insulin
Before the development of recombinant DNA technology, insulin for diabetic patients was extracted from the pancreas of animals, often causing allergic reactions. Genetic engineering provided a breakthrough with human insulin production. This was achieved by:

1. Insulin structure: Human insulin comprises two polypeptide chains (A and B) linked by disulfide bonds.
2. Production of human insulin: In 1983, the company Eli Lilly developed synthetic human insulin by inserting DNA sequences for the A and B chains into E. coli bacteria. The bacterial cells produced insulin, which was then combined to form a functional hormone.

Gene Therapy
Gene therapy offers a method for correcting genetic disorders by inserting functional genes into a patient’s cells. One of the first successful cases of gene therapy was for adenosine deaminase (ADA) deficiency, a disorder that affects the immune system. Treatment involved:

1. Insertion of ADA gene: Lymphocytes from the patient were extracted and cultured, then genetically modified to carry a functional ADA gene. These modified cells were reintroduced into the patient to restore immune function.
2. Potential for permanent cure: If the gene therapy is applied at an early embryonic stage, it could potentially cure the patient permanently.

Molecular Diagnosis
Early diagnosis is crucial for effective treatment, and biotechnology has enabled the development of more precise diagnostic tools. PCR (Polymerase Chain Reaction) and ELISA (Enzyme-Linked Immunosorbent Assay) are commonly used techniques for detecting pathogens and genetic disorders:

1. PCR: This technique amplifies DNA, allowing for the detection of even minute quantities of pathogens, such as HIV or cancer-causing mutations.
2. ELISA: Based on antigen-antibody interactions, ELISA detects the presence of pathogens by identifying specific proteins or antibodies in the patient’s blood.

Transgenic Animals

Transgenic animals are those that have been genetically modified to carry foreign genes. These animals are primarily used in research to understand the role of specific genes in development, physiology, and disease. Over 95% of transgenic animals are mice, but other species, including pigs, sheep, and fish, are also used. The main applications include:

1. Study of gene regulation: Transgenic animals help researchers explore how genes regulate body functions and development. For example, insulin-like growth factors can be studied by introducing specific genes and observing their biological effects.
2. Disease models: Transgenic animals serve as models for studying diseases like cancer, cystic fibrosis, and Alzheimer’s. These models help in the development of new treatments.
3. Biological products: Transgenic animals can be engineered to produce valuable proteins. For example, the transgenic cow Rosie produced milk enriched with human protein alpha-lactalbumin, making it a more balanced nutritional option for infants.
4. Vaccine safety testing: Transgenic mice are increasingly used to test vaccine safety, reducing the need for primates in vaccine trials.
5. Chemical safety testing: Transgenic animals are also used for testing the safety of chemicals and drugs by making them more sensitive to toxins.

Ethical Issues

Biotechnological advancements, especially in genetic modification, have raised significant ethical concerns. These include the potential risks of introducing genetically modified organisms into ecosystems and the fairness of patenting biological resources. Key ethical issues include:

1. GMOs in ecosystems: The introduction of GMOs into the environment could have unpredictable consequences, potentially disrupting ecosystems.
2. Biopiracy: Many companies exploit biological resources from developing countries without proper compensation, leading to disputes over ownership and intellectual property rights. For instance, the patenting of Basmati rice by an American company in 1997 sparked controversy, as the rice variety was derived from traditional Indian strains.

Important Note:
The Indian government has established the Genetic Engineering Approval Committee (GEAC) to regulate GMO research and ensure the safe introduction of GMOs into public use.

Table of Key Biotechnological Applications

MCQ:

Which of the following best describes Bt toxin in genetically modified crops?
(a) A chemical pesticide sprayed on crops
(b) A protein produced by a bacterium that kills specific insects
(c) A herbicide that prevents weed growth
(d) A natural fertilizer used in organic farming
Answer: (

b) A protein produced by a bacterium that kills specific insects.