Biotechnology Principles - State TET Mathematics

Biotechnology: Principles and Processes

Definition and Scope of Biotechnology

Biotechnology involves the use of living organisms, cells, or their enzymes to produce products and processes beneficial to humans. It integrates natural sciences with cellular and molecular analogs such as DNA, RNA, and proteins to generate useful products and services. Both traditional and modern biotechnology are encompassed within this field.

• Key definition: Techniques using living organisms or enzymes to create products/processes useful to humans.
• European Federation of Biotechnology definition: Integration of natural sciences, organisms, cells, parts, and molecular analogs for products and services.

Traditional vs Modern…

Biotechnology: Principles and Processes

Definition and Scope of Biotechnology

Biotechnology involves the use of living organisms, cells, or their enzymes to produce products and processes beneficial to humans. It integrates natural sciences with cellular and molecular analogs such as DNA, RNA, and proteins to generate useful products and services. Both traditional and modern biotechnology are encompassed within this field.

• Key definition: Techniques using living organisms or enzymes to create products/processes useful to humans.
• European Federation of Biotechnology definition: Integration of natural sciences, organisms, cells, parts, and molecular analogs for products and services.

Traditional vs Modern Biotechnology

Biotechnology is divided into traditional and modern types based on the organisms involved and the scale of production. Traditional biotechnology uses microbes for small-scale production, while modern biotechnology employs genetically modified organisms for large-scale production and advanced applications.

• Traditional biotechnology: Uses microbes, produces items like curd, bread, wine; small-scale.
• Modern biotechnology: Uses genetically modified organisms, enables gene synthesis, gene therapy, vaccines, and correction of defective genes; large-scale.

Principles of Biotechnology

The two main principles are genetic engineering and bioprocess engineering. Genetic engineering alters the chemistry of genetic material, while bioprocess engineering ensures the growth of desired organisms in sterile environments for large-scale product manufacture.

• Genetic engineering: Techniques to alter genetic material and introduce it into host organisms to change phenotype.
• Bioprocess engineering: Maintenance of sterile, contamination-free environments for large-scale growth and product manufacture.

Advantages and Disadvantages of Biotechnology

Biotechnology offers advantages over traditional techniques, especially in terms of precision and control over genetic material. However, it also has limitations, such as the possibility of introducing undesirable genes.

• Asexual reproduction: Preserves genetic material but lacks variation.
• Sexual reproduction: Provides variation but some may be harmful.
• Traditional hybridization: May introduce undesirable genes.
• Genetic engineering: Allows isolation and introduction of only desired genes, but sometimes undesirable genes may also be included due to microscopic process limitations.

Steps in Genetic Engineering

The process of creating genetically modified organisms involves three basic steps: identification of the desired DNA, introduction into the host, and maintenance/multiplication within the host.

1. Identification: Locate and isolate the gene of interest from DNA.
2. Introduction: Combine the gene with a vector and insert into the host organism.
3. Maintenance: The recombinant DNA multiplies within the host, producing multiple copies.

Tools of Recombinant DNA Technology

Three essential components are required: enzymes, vectors, and host cells. Each plays a specific role in the manipulation and transfer of genetic material.

• Enzymes: DNA polymerase, nucleases, ligases.
  • Nucleases: Break nucleic acids; exonucleases cut from ends, endonucleases cut at specific internal sites.
  • Restriction endonucleases: Recognize palindromic sequences and cleave DNA at specific sites, producing sticky ends.
  • Ligases: Act as molecular glue to join DNA fragments.
• Vectors: Vehicles for gene transfer, must have origin of replication (ori), selectable markers (e.g., antibiotic resistance genes), and unique recognition sites for restriction enzymes.
• Host cells: Commonly E. coli, used for cloning and multiplication.

Cloning Vectors and Selectable Markers

Vectors such as plasmids and bacteriophages are used to transfer genes. Selectable markers help identify transformed cells. The structure and function of vectors like pBR322 and pUC8 are crucial for efficient cloning.

• pBR322: Contains ori, ampicillin resistance (amp^r), tetracycline resistance (tet^r), and multiple restriction sites.
• Selectable markers: Antibiotic resistance genes (ampicillin, tetracycline, kanamycin, chloramphenicol) help distinguish recombinant from non-recombinant cells.
• Insertional inactivation: Insertion of gene of interest inactivates a marker gene, allowing identification of recombinants (e.g., loss of tetracycline resistance).

Transformation and Screening of Recombinants

Transformation is the process of introducing recombinant DNA into host cells. Screening involves identifying cells that have successfully taken up recombinant DNA using antibiotic selection or colorimetric markers.

• Transformation outcomes:
  • No DNA uptake: non-transformant.
  • Uptake of vector only: transformant, non-recombinant.
  • Uptake of recombinant DNA: transformant, recombinant.
• Screening: Growth on antibiotic media distinguishes between non-transformants, non-recombinants, and recombinants.
• Blue-white screening (pUC8): lacZ gene produces β-galactosidase; insertional inactivation leads to white colonies (recombinant), blue colonies (non-recombinant) on X-gal medium.

Specialized Vectors: Ti Plasmid and Others

Certain vectors are used for specific organisms. The Ti plasmid from Agrobacterium tumefaciens is used for plant genetic engineering after disarming its tumor-inducing genes.

• Ti plasmid: Causes crown gall disease in plants; disarmed Ti plasmid delivers gene of interest without causing tumors.
• Other vectors: Bacteriophages (high copy number), retroviruses (after disarming pathogenic genes).

Methods of Introducing Recombinant DNA into Host Cells

Several physical and chemical methods are used to introduce recombinant DNA into host cells, depending on the organism and application.

• Microinjection: Direct injection of DNA into the nucleus.
• Biolistic (gene gun): DNA coated on gold/tungsten particles is shot into cells.
• Heat shock method: Cells treated with divalent cations (e.g., Ca²⁺), then subjected to heat shock (42°C) and cold to facilitate DNA uptake.
• Competent cells: Cells made permeable to DNA by chemical/physical treatment.

Steps in Recombinant DNA Technology

The process involves a series of steps from DNA isolation to product extraction. Each step is critical for successful genetic engineering.

1. Isolation of DNA: Use of specific enzymes (lysozyme for bacteria, chitinase for fungi, cellulase for plants) to break cell walls and release DNA.
2. Fragmentation: Restriction endonucleases cut DNA into fragments.
3. Separation (Gel Electrophoresis): DNA fragments separated by size using agarose gel; stained with ethidium bromide and visualized under UV light.
4. Elution: Desired DNA fragment is extracted from the gel.
5. Amplification (PCR): DNA is multiplied using primers, template DNA, and Taq polymerase through cycles of denaturation (95°C), annealing (55°C), and extension (72°C).
6. Ligation: DNA fragment joined to vector using DNA ligase.
7. Introduction into Host: Recombinant DNA introduced into host cells by transformation methods.
8. Culturing: Host cells grown in bioreactors for large-scale production.
9. Downstream Processing: Separation, purification, formulation, and quality control of the final product.

Bioreactors and Culture Methods

Bioreactors are used for large-scale culturing of genetically modified organisms. Two main types are batch and continuous (open) cultures, each with distinct features and growth patterns.

• Batch culture (closed): No addition/removal during process; shows lag, exponential, and stationary phases.
• Continuous culture (open): Continuous addition/removal of media and waste; maintains exponential growth phase.
• Types of bioreactors: Stirred-tank (curved base), sparged-stirred (flat base).
• Lab vs bioreactor: Lab scale is small (10–20 L), bioreactor scale is large (up to 1000 L); bioreactors allow optimal temperature and growth conditions.

Downstream Processing

After culturing, the product undergoes downstream processing for separation, purification, and formulation. Quality control is essential before the product is marketed.

• Separation and purification: Removal of impurities and concentration of the product.
• Formulation: Addition of preservatives and packaging.
• Quality control: Strict testing to ensure product safety and efficacy before release.