Transcript Chapter 7: Animal Biotechnology

Chapter 7
Animal Biotechnology
Animals in Research
Animals in Research
B1
B2
B3
B4
Animals in Research
Animation of
Drug
Development
Process
Animals in Research
z Animal Models
• Mice
• Rats
• Zebrafish (3 month generation time,
200 progeny, complete embryogenesis
in 120 hrs)
• Dogs (lungs and cardiovascular
system)
• Cats
• Pigs (PPL Therapeutics- delete a gene
which causes hyperacute rejection of
pig-to-human organ transplantation)
• Primates (HIV and AIDs research,
geriatric research)
Animals in Research
z Alternatives to Animal Models
• Cell culture devices
• Researchers use cell cultures and computer-generated
models whenever possible, but this doesn’t work for looking
at an organ or entire animal
Animals in Research
z Regulation of Animal Research
• The “Three Rs”
• Reduce the number of higher species (cats, dogs,
primates) used
• Replace animals with alternative models whenever
possible
• Refine tests and experiments to ensure the most
humane conditions possible
Animals in Research
z Veterinary Medicine as Clinical Trials
• Treatments for humans may also be useful for
treatments with animals (e.g. the BRCA1 gene found
in 65% of human breast tumors is similar to the
BRCA1 gene in dogs)
• Hyperthermia + radiation = more effective at killing
tumors
• Stimulation of cytokines for curing skin cancers
Animals in Research
z Bioengineering Mosquitoes to Prevent Malaria
• Cloned in a gene that prevents the parasite from
traversing the midgut; blocking the continuation of its
life cycle
• Developed an antibody that prevents the parasite
from entering the mosquito’s salivary gland
Clones
z Cloning
• Creating Dolly
• Limits to Cloning: The donor cell must
come from a living organism
• An organism is also shaped by its
environment
• The success rate for cloning is very low
• Clones may be old before their time
• The future of cloning: preservation of
endangered animals, studying the effect
of drugs etc on duplicates, improve
agricultural production
Transgenic Animals
z
z
z
z
Retrovirus-mediated transgenesis
Pronuclear microinjection
Embronyic stem cell method
Sperm-mediated transfer
Transgenic Animals
z Improving Agricultural Products
with Transgenics
• Faster growth rates or leaner
growth patterns (improve the
product), more product
• Increase nutritional contentlactoferrin
• Turning the animals into efficient
grazers
• Transfer antimicrobial genes to
farm animals
Transgenic Animals
z Transgenic Animals as Bioreactors
• Biosteel otherwise known as spider silk, cloned into
goat milk (“silkmilk” goats)
• Goats reproduce faster than cows and are cheaper than
cows
• Hens also make good bioreactors in that they are cheap
and a lot of eggs are produced at one time
Transgenic Animals
z Knock-outs: A Special Case of
Transgenesis
• A specific gene is disrupted or
removed such that it is not expressed
• Procedure: DNA is modified, it is
added to embryonic stem cells,
where it undergoes homologous
recombination. The modified ES cells
are then introduced into normal
embryo. The embryo is implanted in
an incubator mother. The offspring is
a chimera. It may take several
generations of crossbreeding are
required to produce animals that are
complete knock-outs.
• Breast cancer mouse
Producing Human Antibodies in
Animals
z Production of Monoclonal
antibodies (Mabs)
•
•
Used to treat cancer, heart
disease, and transplant
rejection
HUMANIZED monoclonal
antibodies were developed
to prevent the human antimouse antibody (HAMA)
response