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.