Application of biotechnology on various aspects

App of biotechnology on various aspects

1. Applications of Biotechnology By, DR. Ratan Chowdhury Assistant Professor, Department of botany Rang apara college

2. Bt cotton is genetically modified to express genes from the bacterium Bacillus thuringiensis ( Bt ), which naturally produces proteins toxic to specific insect pests. These Cry proteins (crystal proteins) are insecticidal. When larvae (mainly caterpillars of the order Lepidoptera) ingest Bt cotton, the Cry proteins bind to gut receptors, disrupt their digestive cells, and eventually kill them. Different strains of B. thuringiensis target different insects. Some affect beetles (Coleoptera) and flies (Diptera). What is Bt Cotton?

3. Larvae ingest Bt spores and Cry proteins. In the gut, the Cry proteins are activated by digestion. These activated toxins bind to receptors in the insect gut lining, causing cell lysis (bursting) and death. How Does Bt Cotton Work?

4. Bollgard cotton, developed by Monsanto, was the first Bt cotton used commercially in the US (1996). It produces Cry1Ac toxin, which is especially effective against tobacco budworm and pink bollworm. Other generations like Bollgard II, Bollgard III, and WideStrike use multiple Cry proteins for broader pest control. Commercial Use and History

5. Reduces the need for chemical insecticides. Controls major pests effectively. Helps improve yield and reduce crop loss. Advantages of Bt Cotton

6. Over time, pests can develop resistance to Cry proteins. Solutions include: Refuge strategy: Planting non- Bt crops nearby to maintain susceptible insect populations. Pyramiding Bt genes: Using multiple Cry proteins with different targets to make resistance development less likely. Challenges and Resistance

7. Cry proteins are highly specific to insect pests and generally safe for humans and other animals. As cotton is a fiber crop, the risk of these toxins entering the food chain is minimal. Extensive testing indicates low public health risk from  Bt  cotton. Environmental and Health Impact

8. It was the first genetically modified (GM) food crop to be approved for commercial sale and human consumption. It was developed by a California-based company called Calgene and released in 1994 . Key Features: Delayed Ripening : The main goal of the Flavr Savr tomato was to slow down the ripening process , allowing the tomato to stay fresh longer after harvesting. This was achieved by silencing a gene that produces the enzyme polygalacturonase , which breaks down pectin in the cell walls and causes softening. Genetic Modification : Calgene inserted an antisense gene to block the expression of the polygalacturonase enzyme, which helped the tomato maintain its firmness for a longer period during transportation and shelf life. The Flavr Savr tomato

9. Advantages: Longer shelf life and reduced spoilage. Better flavor retention due to vine-ripening (as they didn’t have to be harvested early and artificially ripened). Challenges: High production cost. Mixed public perception and resistance to GM foods. Logistic and commercial difficulties in farming, distribution, and acceptance. Outcome: Although it was a scientific milestone, Flavr Savr tomatoes were not commercially successful and were withdrawn from the market by the late 1990s. However, they paved the way for future developments in genetically modified crops.

10. What is Human Insulin? Human insulin is a hormone made by the pancreas that helps regulate blood sugar levels by allowing cells to absorb glucose for energy or storage. It's composed of two polypeptide chains: A-chain with 21 amino acids B-chain with 30 amino acids These chains are connected by disulfide bonds , forming a stable, active molecule.

11. Recombinant Human Insulin ( rHu ) Recombinant insulin is genetically engineered to be identical to natural human insulin . It is produced using recombinant DNA technology , typically in bacteria like E. coli or yeast.

12. Steps in Insulin Production (Based on Fig. 17.3): Gene Isolation : The genes coding for insulin A and B chains are separately inserted into plasmids containing the β-galactosidase (β-gal) gene for fusion protein expression. Transformation : These recombinant plasmids are introduced into E. coli cells . Protein Expression : The bacteria are cultured, and they produce β-gal-insulin fusion proteins . Protein Purification : The fusion proteins are isolated, and the insulin chains (A and B) are separated using CNBr (cyanogen bromide) . Chain Assembly : The purified A and B chains are combined in vitro, where disulfide bonds are formed to create functional insulin.

13. Applications of Recombinant Insulin Widely used in treating Type 1 and advanced Type 2 diabetes . Used in cell culture media for: Stem cell research Adipogenic differentiation GLUT4 translocation studies Supplementing epithelial and other cell lines

14. Advantages of Recombinant Insulin Biologically identical to natural human insulin. Reduces allergic reactions common with animal-derived insulin. Can be produced in large quantities . Ethical and safe for long-term use.

15. Golden Rice: An Overview 1. Why Golden Rice was developed: Over 1.02 billion people globally suffer from micronutrient deficiencies , especially Vitamin A deficiency (VAD) . VAD can lead to serious health problems like: Xerophthalmia (including night blindness and corneal scars) Higher risk of child mortality from diseases like measles and diarrhea It affects around one-third of children aged 6 to 59 months (as of 2013).

16. What is Golden Rice? Golden Rice is a genetically modified (GM) variety of rice ( Oryza sativa ). It is engineered to produce beta-carotene , a precursor of Vitamin A, in the edible parts of the rice. Intended to serve as a fortified food to combat Vitamin A deficiency.

17. Development and Scientific Basis: Golden Rice was created using two key genes : psy (phytoene synthase) – taken from daffodil ( Narcissus pseudonarcissus ) crtI (phytoene desaturase) – from a soil bacterium ( Erwinia uredovora ) These genes were inserted into the rice endosperm under a specific promoter , ensuring beta-carotene is produced in the part of the rice people eat.

18. Biosynthesis Pathway: Starts with Geranylgeranyl diphosphate (GGPP) . Sequence of enzymatic reactions leads to the production of: Lycopene Alpha- and Beta-carotene (via lycopene cyclase ) These carotenoids are precursors to Vitamin A .

19. Key Milestones: The rice was the product of an 8-year research project by: Ingo Potrykus (Swiss Federal Institute of Technology) Peter Beyer (University of Freiburg) First field trials in 2004 (Louisiana State University), followed by trials in Philippines, Taiwan, and Bangladesh . The original line was called SGR1 . Greenhouse-grown Golden Rice produced 1.6 µg/g of carotenoids ; field-grown versions produced 4–5 times more .

20. Challenges and Reception: Faced opposition from environmental and anti-globalization activists. However, in 2016 , over 100 Nobel laureates supported its use, citing its potential health benefits.