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Artemia franciscanaNorth American brine shrimp
(Crustacea, Anostraca)
HATCH
Artemia
life
cycle
fertilized eggs in
brood sac
Adult female
winter ‘eggs’
Artemia franciscana (dry, encysted ‘winter eggs’)
‘Paint’ dry cysts on double-stick tape with small, soft, dry paintbrush
Method Apaint cysts on sticky circle
plastic petri dishtransparency strip with grid
10 mm x 10 mm
strip of double-stick tape covers grid
tape holds strip to dish
Method B
Cysts painted on sticky grid with brush
STUCK-on ARTEMIATechnical Advantages
easy handling & transfer of cysts
uses small, quantifiable number of cysts
follow development of individual cysts
cysts stay in single focal plane
use dissecting or compound microscope
manipulation of many relevant variables
Hatching of encystedArtemia embryosA1-A2: Encysted
late gastrula stage(immersed in sea water and stuck to tape)
B: Cyst hydrates and swells; cyst wall splits
C1-C2: “Umbrella” stage emerges (membrane-bound)
D1-D2: Nauplius larvae are free swimming
A1
B
A2
C1
C2
D1 D2
Each day, use pipet to remove and count hatched, swimming nauplius larvae
Treatment Group (control or experimental) _________________ Initial number of cysts in dish _____
# of hatched nauplius larvae
removed
Cumulative # of hatched nauplius
larvae (day 1 + 2 + 3…)
Cumulative hatching % (cumulative # of hatched
larvae / initial number of cysts X 100)
Day 0 start
Day 1(24 h)
Day 2(48 h)
Day 3(72 h)
Day 4(96 h)
0
50CONTROL
0 0%
22 22 44%
39
11 33
6
1 40
78%
80%
66%
0
20
40
60
80
100
day 0 day 1 day 2 day 3 day 4
%HATCH
Typical hatching curve:
2. ambient light effects during hydration
5. second hydration
1. dry cysts exposed to thermal extremes
3. temperature effects during hydration
4. salinity effects
Examples of experimental variables that may affect hatching curves
6. oxygenation effects during hydration
7. environmental toxicant effects
8. irradiation effects on dry or hydrating cysts
Measurements & End-points
* Hatching % *
hatching time-coursedevelopmental anomalies
larval motility molting & growth
'N Cyst'N Cyst
A sea monkey's no monkey or chimp. It's crustacean - better known as brine shrimp.
This genus Artemia Can deal with extremia.
As a cyst stage, its hardly a wimp.