L4 - techniques - microscopy and animal models

Question 1

phase contrast microscopy

Answer 1

light passing through is scattered
transparent specimens
set up interference patterns in light

Question 2

why cant we use light illumination

Answer 2

toxic

free-radical production causes growth cones to shirvel up

Question 3

revolutionary technique

Answer 3

fluorescence

Question 4

fluorescence

Answer 4

emits light at a different wavelength

invisible to humans

Question 5

luminescent

Answer 5

makes its own light

Question 6

fluorescent animals

Answer 6

budgie
stingray
scorpion

Question 7

jellyfish = fluorescent and luminescent

Answer 7

makes its own light to create fluorescence

Question 8

nobel prize GFP

Answer 8

2008

Question 9

features of GFP

Answer 9

barrel-shaped
fluorophore in centre
blue light enters, green light (longer wavelength/less energy) emitted

Question 10

eGFP

Answer 10

Enhanced (mutated) GFP

Question 11

brainbow

Answer 11

many fluorescent proteins used
e.g. cherry RFP
useful bc greyscale is tricky to see and differentiate

Question 12

advantages of phase contrast microscopy

Answer 12

low illumination
no labelling required
cheap

Question 13

disadvantages of phase contrast

Answer 13

can only differentiate structures with high contrast

Question 14

advantages of fluorescent widefield microscopy

Answer 14

allows discrimination of up to 3 or 4 fluorophores

high temporal resolution

Question 15

disadvantages of fluorescent widefield

Answer 15

high illumination

limited depth of information

Question 16

advantages of confocal microscopy

Answer 16

accurate 3D spatial resolution
discrimination of multiple fluorophores
automated image analysis

Question 17

disadvantages of confocal

Answer 17

expensive
high illumination
long acquisition time

Question 18

confocal microscopy

Answer 18

confocal laser scanning microscopy - CLSM

optical imaging technique

increases optical resolution and contrast of a micrograph
uses a spatial pinhole to block out-of-focus light in image formation.

Question 19

advantages of mice as animal models

Answer 19

similar cortical structure
mammalian
- genes/proteins therefore conserved

Question 20

disadvantages of mice

Answer 20

expensive

ehtical issues

Question 21

advantages of frogs

Answer 21

vertebrate so conserved genes/proteins

produces hundreds of oocytes

Question 22

disadvantages of frogs

Answer 22

non-mammalian

limited behavioural tests possible

Question 23

advantages of using fruit fly

Answer 23

fast life-cycle
readily genetically manipulated
used to model Alzheimers/parkinsons

Question 24

disadvantages of fruit fly

Answer 24

invertebrate

therefore limited conservation of proteins

Question 25

advantages of using chick embryo

Answer 25

ethically fine - no licence needed
minimal husbandry costs - chicks are cheap
evolutionary conserved developmental events (heart beat day 2)
ready source of primary neurons
similar visual system
good for modelling congenital defects