Biotechnology and Society

Biotechnology and Society

What is Biotechnology?

• Biotechnology involves the use of recombinant DNA and molecular biology.
• It produces commodities such as drugs and better crops, and services such as diagnostic tests and individual identification.

Making Human Proteins in Bacteria

• One of the first biotech successes was making human proteins in bacteria.
• Insulin for Type I Diabetes was originally extracted from cow and pig pancreas.
• Recombinant DNA technology is safer.
• The process involves:
  • Cutting a plasmid with an enzyme.
  • Inserting the human insulin gene into the plasmid.
  • Inserting the engineered plasmid into a new bacterium.
  • The bacterium divides and begins producing insulin.

Other Human Products from Bacteria

• Several human products can be produced from bacteria:
  • Abatacept (New fusion protein): Treatment for Rheumatoid arthritis
  • Atrial natriuretic hormone (Human protein): Hypertension, heart failure
  • Epidermal growth factor (Human protein): Burns, skin graft survival
  • Factor VIII, X (Human protein): Blood clotting disorders
  • Follicle Stimulating Hormone (Human protein): Infertility
  • Insulin (Human protein): Diabetes
  • Human growth hormone (Human protein): Dwarfism, growth defects
  • Herceptin (Human antibody): Breast cancer

Human Products in Animals

• Some human proteins require mammalian modifications.
• Cows, goats, and sheep can be used.
• Only cells in mammary glands produce transgenic protein via a DNA switch.
• The protein is purified from the animal's milk.
• Drugs for the treatment of cystic fibrosis, blood clotting disorders, and anaemia are being tested.

Human Products in Plants

• Low cost, but often also low yield.
• Examples:
  • Hemoglobin (Tobacco): Blood substitute
  • Serum albumin (Tobacco): Burns/fluid replacement, blood extender
  • Protein C (Tobacco): Anticoagulant
  • Hirudin (Canola): Anticoagulant
  • α₁-Interferon (Rice): Viral protection, anticancer
  • ẞ-Interferon (Rice/tobacco/turnip): Treatment for hepatitis B + C
  • Y-Interferon (Tobacco): Phagocyte activator

Genetically Modified Foods

• Selective breeding has been used for thousands of years for yield, nutrition, and flower color.
• Examples from Wild Mustard Plant (Brassica Oleracea):
  • Brussels sprouts (Lateral leaf buds)
  • Broccoli (Flower buds/stems)
  • Cabbage (Terminal leaf bud)
  • Cauliflower (Flower buds)
  • Kale (Leaves)
  • Kohlrabi (Stem)

Selective Breeding - Plants

• Used in many agricultural species.
• Helped with domestication and crop improvement.
• Example: Teosinte to Modern Corn

Selective Breeding - Animals

• Mostly agricultural.
• Example: European toy dogs, Gray wolf (common ancestor)

Selective Breeding Issues

• Reduced genetic variation.
• Vulnerability of entire crops or herds.
• Selective breeding of undesirable characteristics.

Genetically Modified Foods

• Biotechnology is used more often these days.
• Selectively adding only certain genes from another plant, animal, bacteria, or fungus.
• Used for pesticide and insect resistance.

Genetically Modified Foods

• Improved nutritional value, e.g., Golden Banana (boosted Vitamin A).
• Many other varieties in development.

Genetically Modified Foods - Concerns

• Will insects develop resistance?
• Can insecticide/pest resistance be passed to wild plants?
• Are GMO foods safe to eat? Allergies?

Biotechnology and Identification

• DNA profiling developed in the 1980s.
• Variable Number Tandem Repeats (VNTRs): Repetitive DNA is inherited; the number of repeats can differ between chromosomes and individuals.

Biotechnology and Identification

• Restriction Enzyme recognition sequences flank the VNTRs.
• Produces thousands of DNA fragments; sizes depend on the number of repeats between sites.

Biotechnology and Identification

• Fragments are separated by electrophoresis.
• Fragments all overlap, generating a smear.

Biotechnology and Identification

• Transfer DNA to more stable membrane.
• Add radioactively labeled DNA probes.
• Expose to X-ray film.
• Results in an individual pattern.

Biotechnology and Identification

• Compare x-ray film profiles to identify individuals.

Biotechnology and Identification

• Technique now includes PCR (Polymerase Chain Reaction).
• Coloured primers help detection.
• Multiplex PCR.

Biotechnology and Identification

• Applications:
  • Criminal cases
  • Paternity cases
  • Missing persons
  • Mass disasters
  • Biohistory
  • Cancer studies
  • Military DNA “dog tags”
  • Twin zygosity
  • Prenatal testing

Stem Cells as Disease Treatment

• Two types:
  • Embryonic Stem cells: from the blastocyst - can become anything = pluripotent
  • Adult stem cells: from adult tissues and organs - limited cell types = multipotent
  • Induced pluripotent stem cells (iPS)

Stem Cells

• Pluripotent vs Multipotent

Stem Cells for Basic Research

• Discovering what pushes cells down a particular path of development.
• Using iPS to study disease processes.
• Collections of cells are made available for research.

Stem Cells for Treating Disease

• Embryonic stem cells offer the most promise, but are an issue ethically.
• Adult stem cells provide a limited, but more ethical alternative.
• Routinely used in bone marrow transplants.

Stem Cells for Treating Disease

• Patient's own stem cells can sometimes be used.
• The Autologous Transplant Process:
  1. Collection: Stem cells are collected from the patient's bone marrow or blood.
  2. Processing: Blood or bone marrow is processed in the laboratory to purity and concentrate the stem cells.
  3. Cryopreservation: Blood or bone marrow is frozen to preserve it.
  4. Chemotherapy: High dose chemotherapy and/or radiation therapy is given to the patient.
  5. Reinfusion: Thawed stem cells are reinfused into the patient.

Spray-on Skin

• Patient's own skin cells improve burn recovery.
• Process: Harvest stem cells, stem cells sprayed onto burn site.

CRISPR-Cas9 Gene Editing

• CRISPR = Clustered Regularly Interspaced Short Palindromic Repeat
• Cas9 = enzyme which cuts DNA
• CRISPR-Cas9 system was discovered in archaea then bacteria.
• A defense mechanism against viruses.
• When viruses invade, the bacteria destroys them with enzymes, but they keep a bit of their genome.
• Helps the bacteria remember for next time.

CRISPR-Cas9 in Bacteria

• First infection: Foreign fragment acquired to the CRISPR locus.
• Second infection: Cleavage of foreign DNA.
• Bacterial resistance to the virus.

Bacterial immune system

• A guide RNA directs Cas9 to the invading DNA, leading to a site-specific double-strand break.

CRISPR-Cas9 Gene Editing

• CRISPR-Cas9 system makes blunt-ended cuts.
• The cell will attempt to repair the breakage.
• The natural repair process may result in the loss of some DNA sequence – which could be useful.
• Or we can help the DNA repair mechanisms correct the mistake by providing some complementary DNA to act as a template.

CRISPR-Cas9 Gene Editing

• NHEJ (Non-Homologous End Joining)
• HDR (Homology Directed Repair)

CRISPR-Cas9 Gene Editing

• Applications:
  • Treating cells to resist HIV
  • Preventing malaria in mosquitos
  • Modifying T-cells to treat leukaemia
  • DMD treated in mice
  • Editing genes in pigs for transplant
  • Improving eyesight in rats
  • Hairy goats, Muscly dogs, Micropigs

CRISPR-Cas9 and Xenotransplantation

• 1,800 Australians on the waiting list for an organ.
• 14,000 Australians on dialysis.
• Must meet specific requirements to donate.

CRISPR-Cas9 and Xenotransplantation

• Can we use organs from other animals for humans?
• Reliable and reproducible source of organs.
• Can be grown in controlled conditions to ensure animals are free from disease.
• Two significant issues to overcome:
  1. Activation of viruses
  2. Transplant rejection

Virus Transmission

• Ancient viruses may be able to be reactivated.
• Transmission of other viruses is also possible.

Transplant Rejection

• The immune system is designed to identify foreign ‘invaders’.
• Human-to-human transplantation is mediated with immunosuppressants.
• Xenotransplantation much more difficult.

CRISPR-Cas9 and Xenotransplantation

• Edit out genes for pig cell surface markers.
• Edit in human genes.
• Direct integration of new DNA with precision.

CRISPR-Cas9 and Xenotransplantation

• 2021 – Jim Parsons received two pig kidneys – 77 hours
• 2022 – David Bennett Sr received a pig heart – 2 months
• 2024 – Richard Slayman received a pig kidney – still alive

Precision Medicine

• Combines many different areas of information to provide a more personalized approach to health treatment.
• ECU Centre for Precision Health: Cancer, neurologic conditions, chronic and metabolic conditions.