lec 9 - animal & plant biotech Flashcards
(72 cards)
1
Q
list (4)
genetically engineered animals used to…
A
- better understand animals
- develop new medical treatments
- improve food supply
- produce medicinal compounds
2
Q
why do we use animal models?
A
- genetic and physiological similarities btw animals and humans
- test on animals before humans
- benefits animal health (vaccines, etc.)
3
Q
examples of model organisms
A
purebred mice, zebrafish, drosophila, c. elegans, dogs, monkeys, chimps –> must choose right one for best response
4
Q
which is superior? rats or mice?
A
rats better for early drug toxicity tests –> more human like responses, larger size easier to do surgeries on, more toxicological data
5
Q
cats, dogs, primates
A
used when there’s no other choice –> when their biology is important to research
6
Q
dog and human similarity
A
lung and cardiovascular system
7
Q
primates and human similarity
A
monkeys and chimps are only known animals susceptible to HIV like humans are
8
Q
why are primates still not good model?
A
- genetically variable –> results cannot be generalized
- success of a clinical trial on monkeys couldn’t be repeated in another set of primates
9
Q
kidney on a chip
A
- using cells in vitro instead of animals
- determining drug dosing –> microfluidic chip delivers flow of medication across cultured kidney cells and alter flow thry device to stimulate varying levels of kidney function
10
Q
why is testing on chips better than animals?
A
- animals metabolize medications a lot faster than humans –> underestimated toxicity
- chip is more accurate, closely replicates our environments
11
Q
computer generated models
A
- big data to build predictive models –> could replace animal testing
- stimulates specific molecule and chemical structures and their interactions
- limited by programming and knowledge of how physiological systems work
12
Q
list (3)
animal testing regulations
A
- reduce number of higher species used
- replace animals with alternative models whenever possible
- refine tests and experiments for most humane conditions possible
13
Q
sharks and camels…
A
have mini-antibodies (only heavy chains) instead of ours (2 heavy, 2 light) –> more compact (just express antigen binding site) –> drugs for cancer and diseases
14
Q
list (5)
mini-antibodies advantages
A
- easier to make (in e. coli)
- more durable
- more soluble
- works intracellularly
- better access deep in tissues
15
Q
list (8)
nanobodies applications
A
- tracks proteins
- label cancer cells
- crystallography
- target proteins for degradation
- reversible knockdown
- nanobody-based flu vaccine
- target immune-boosting cytokines or radiation directly to tumors
- crosses BBB
16
Q
list (2)
nanobodies drawbacks
A
- rapid excretion (leaves body before patient receives full benefit)
- can’t enter cells on their own
17
Q
dolly the sheep
A
first animal cloned from nucleus of another adult animal –> controversial
18
Q
embryo twinning
A
splitting embryo in half –> identical twins as result of mix of genetic info from 2 parents
19
Q
first embryo twinning
A
- produced 2 healthy calves
- now common practice in cattle industry
20
Q
somatic cell nuclear transfer (SCNT)
A
- harvest egg from organism –> grow in culture –> remove nucleus/DNA from egg (enucleation) –> get somatic donor cells –> starve cells to avoid entering S phase (proliferation)
- place somatic cell nucleus next to egg cytoplasm –> induce fusion with mild electrical charge –> single cell embryo begins developing until blastocyst –> implant into host organism –> normal pregnancy
- cloned individual has exact same DNA as donor
21
Q
list (5)
SCNT limits
A
- donor cell must come from living organism
- clones not exactly identical (shaped by experiences and environment - epigenetics)
- low success rate (2%)
- clones may be old before their time (shortened telomeres bc lifespan starts at age of donor)
- may be born with defects
22
Q
why are clones still necessary?
A
for research –> idential genetics make it easier to sort out results of treatments
23
Q
list (3)
cloning applications
A
- sustain breeding population of endangered species
- improve agricultural productions
- xenotransplants
24
Q
cloning monkeys
A
using SCNT –> produced viable embryos but failed to mature
25
# list (2)
new techniques to improve cloning
- better microscopy to view cells during handling
- compounds that encourage cell reprogramming
26
ideal model organism =
gene editing + cloning
27
transgenic animals
genetically engineered animals for various purposes (disease resistance, increase yield, produce drugs, etc.)
28
transgenic dairy cows
- resistance to mastitis (contagious condition caused by bacteria --> loss of billiong of $ for dairy industry)
- carries gene that produces lysostaphin (kills S. aureus)
29
enviroPig
- transgenic pig expressing enzyme phytase in its saliva --> degrades phosphatases in pig's food
- less phosphorus in pig urine --> major pollutant on pig farms
30
food safety
- transfer antimicrobial genes to farm animals reduces food poisoning deaths
- reduces use of antibiotics in agriculture
31
transgenic goats
engineer goats expressing spider silk protein in their milk --> biosteel (strong)
32
transgenic animals as bioreactors
- produces complex therapeutic proteins
- lower production cost
- higher production capacity
33
improve plant productivity
- selective crossbreeding thru traditional methods, accelerated by direct transfer of genes
- high royalty fees and restrictions (patents)
34
conventional selective breeding and hybridization
sexual cross btw 2 lines --> repeated backcrossing btw hybrid offspring and parents --> takes years
35
polyploid plants
- >2N (whole chromosome sets rather than single genes)
- increases desirable traits (especially size)
36
plant transformation
- direct transfer of genes to plants
- big portion of key crops worldwide --> controversial
37
plant transformation application
development of plants that produce own pesiticides and resistant to herbicides
38
leaf fragment technique
- small discs cut from leaf --> culture in medium containing genetically modified agrobacterium
- DNA from Ti plasmid integrates into host DNA
- leaf discs treated with plant hormones to stimulate shoot and root development --> plant now has gene of interest
39
leaf fragment technique limitation
agrobacterium cannot infect plants that grow from single seed embryos (corn, wheat)
40
gene guns
- solution for plants resistant to agrobacterium
- bombard metal beads coated with DNA into embryonic plant cell --> aimed at nucleus or chloroplast
- use marker genes to distinguish genetically transformed cells
41
chloroplast engineering
DNA in chloroplast completely separate from DNA released in pollen --> no chance for transgenes to be carried by wind to distant crops --> contained
42
genetically modified organisms (GMO)
organisms in which genetic material has been altered by way other than mating or natural recombination
43
why is plant pharmacology good?
- plants are ideal protein factories to grow medicine
- inexpensive edible vaccines
- don't require refrigeration
44
molecular pharming
using phytochemicals that produce chemicals useful to human health --> antibodies, blood products cytokines, growth factors, hormones, enzymes
45
protalix
FDA approved drug to treat gaucher's disease using carrots --> orphan drug
46
# list (7)
plant vaccine advantages
- safer than those produces in animal tissues (no horizontal transmission)
- economical advantage (cheaper to produce, low costs per dose)
- easier to scale up (just grow more plants)
- no refrigeration required by vaccines containing seeds or dried leaves --> good for developing countries
- no skilled medical personnel required
- no injection needed --> no risk of contaminated needles
- elicits mucosal immunity and systemic
47
# list (2)
plant vaccine risks
- resistance to degradation in GI tract
- induction of oral tolerance due to regular intake
48
medicago
expressed flu antigen in tobacco plants --> faster and cheaper
49
vaccine for plant protection (CMV)
- cucumber mosaic virus (CMV)
- create siRNA targeting viral RNA --> sprayed on leaves --> 90% protection
50
vaccine for plant protection (TMV)
- tobacco mosaic virus (TMV)
- vaccine encoded in plant's DNA --> gene from TMV inserted into tobacco plant --> protein produced from viral genes stimulates plant's immune system --> TMV resistance
51
what scab
fungal disease produces toxins in wheat and barley --> protective gene in wheat grass added to wheat --> encodes toxin-destroying enzyme
52
why are genetic pesticides better?
better than conventional pesticides --> kills harmless insects and pests evolve resistance
53
transgenic cry gene
- bt produces crystallized protein (cry) --> toxin kills insects and their larvae --> but washed away by rain
- transgenic plant carries cry gene --> built-in defense against certain insects
54
# list (6)
edits made to plants for expression
- clone downstream to strong plant promoter
- modified to use plant codons
- modification in nucleotide sequences
- elimination of plant consensus splice sites
- elimination of CUUCGG hairpins
- protein expression increased by chaperoning (better folding)
55
to introduce gene into plants, we need...
plant protease inhibitors and amylase inhibitors --> prevents insects from digesting plants --> inactivated by cooking (safe to eat)
56
why do we need transgenic plants for safe storage?
to prevent insect infestation of crops during storage
57
transgenic corn
- expresses avidin --> resistant to pests during storage
- blocks biotin availability (vitamin required for insect growth)
58
why do we need transgenic plants for herbicide resistance?
- traditional weed killers kill desirable plants along with weeds
- genetically engineer crops to be resistant to common herbicides
59
glyphosate and example
- blocks EPSPS, enzyme for plant growth and survival --> crops transgenically produce alternative enzyme (glyphosate resistant EPSPS variant)
- selective killing (crops survive, weeds die)
- most soybeans grown today contain herbicide resistance genes
- but glyphosate resistant weeds has evolved
60
drought and salt-tolerant plants
- droughts account for 70% of crop losses in world
- 40% world's farmland suffers from high salt []s (over-irrigation, over-salting roads)
61
transgenic drought and salt-resistant plants
express enzymes for osmoprotectants --> increase number of solute molecules in cell --> water intake, retention, stabilize macromolecules
62
transgenic plants for enhanced nutrition
- vitamin A deficiency in kids due to famine
- golden rice engineered to contain large amounts of beta carotene (pro-vitamin converted to vit A)
63
# CRISPR-cas in plants
gene inactivation in mushrooms
polyphenol oxidase (PPO) makes mushrooms brown --> knockout gene by not introducing foreign DNA (no disease transmission risk)
64
conventional method of genetic mutagenesis in plants and risks
- plant breeding with chemical mutagens --> introduce random changes into plant DNA
- difficult to make multiple changes in plant at same time
- multiple rounds of manipulation, each one increasing risk of undesired changes
65
CRISPR mutagenesis in plants
- precise alterations to specific DNA sequences
- can multiplex
- improves sustainability
66
genetically edited wood
- engineered poplar tress with less lignin (stiff, woody material)
- lowers papermaking pollution while saving money
67
adding second copy of gene
- boosts yield by 40%
- absorbs more fertilizer, more photosynthesis, accelerates flowering, larger harvests
68
editing gene promoters rather than genes
- fine-tune tomato genes that control yield --> doesn't add foreign genes
- more likely to receive fast track
69
# list (2)
human health concerns
- allergic reactions
- antibiotic resistance marker genes could spread to disease-causing bacteria in humans
- to date, science hasn't supported any of these concerns
70
# list (5)
environmental concerns
- genes for pest or her resistance could spread to weeds (super weeds)
- super bugs
- loss of biodiversity
- biotech companies control agriculture (monopoly)
- regulations
71
environmental concern: glyphosate
common weed killer harmless to animals but may harm bees --> messes with their microbiome
72
ecological concern
- reduced variety is only some variants are used
