Lecture notes Cells and Immunity Animal Models (BI2BC45)

30.10.19


L4 – Animal models
Keywords:


Lecture:
 Ideal model systems:
o Money (fed, cleaned)
o Size of animal (ease of handling)
o Generation time and lifespan
o If genome is sequenced
 Main models
o Drosophila, Caenorhabditis elegans (nematode worm), Danio rerio (zebra fish) and
Arabidopsis (plant)
o Primary cells – come straight from organism (hayflick limit – how many times a cell
can divide until telomere disappears)
 +/- of egs of model organism
o Yeast (fungus) = doubling time of 3h
 Saccharomyces cerevisiae
 Saccharomyces pombe
 Many mutant stains
 Both diploid and haploid life stages (ease of protein change in haploid stage)
 a/α haploids form from haploid spores
 Replica plate- impress same colony onto a new plate – ID mutants (able to
have control of same colony)
o Caenorhabditis elegans (nematode worm) 1mm
 Grown on agar & consume bacteria (GM bacteria alter gene expression in
worm)
 See through = visual ID w/microscopy
 Shows what each cell division becomes (track cellular origin)
 If gene is mutated = shows which cells aren’t synthesized/differently
 Dauer stage larva = hibernation when overcrowded/↓ food instead of 4
larva stages
 Connectome – first species to have EM made of CNS
o Drosopgila melangogaster
 Has appendages that worms do not
 Lifecycle = 7-10 days
 Hox genes discovered in organism (segmentation/appendages)
o Danio rerio (zebra fish)
 Cleaned and heated tanks
 Transparent embryos develop outside mother
 Withstand ↑ levels of radiation = ↑# of mutations
(viral/interbreeding/chem)
 Regeneration ability
 Can form tumors
o Mus musculus (house mouse)
 Diverged 80 mil y/a