Chapter 29
PROTOCOL
Coelenterata
Subprotocol 1
Ectodermal Fragments of Hydra (Hydrozoa)
Materials
- Dissecting microscope
Equipment
- Syracuse dishes
- Sharpened surgical needles
- No.5 watchmakers' forceps
- Plastic petri dishes
- Sterile seawater
Solutions
- Scyphistoma larvae of the marine scyphozoan Aurelia aurita (labo- Animals
ratory grown larvae are fed on freshly hatched brine shrimp,Artemia,
every morning)
Procedure
1. Remove the animals from the stock culture, place them in Syracuse
dishes containing filtered seawater, and starve them for 24 h prior to
operation.
2. Remove the peduncle, hypostome, and tentacles using sharpened surgical needles.
3. Slit the remaining cylinder of tissue lengthwise, flatten it out, and orientate it so that the endodermallayer is facing upward.
4. Cut the tissue into six strips, each approximately 0.5 mm wide and the
length of the original cylinder(approximately 1 mm).
5. Hold the rectangular piece of tissue with no. 5 watchmakers' forceps
while a cut is made in the tissue to the level of the mesoglera using a
surgical needle.
1. Separate the endoderm from the ectoderm by teasing and cutting
through the mesoglera (in Aurelia, the ectoderm is unpigmented,
whereas the endoderm contains an orange pigment; therefore, it is
easy to distinguish these tissues).
1. Transfer the endoderm-free isolates into a plastic petri dish containing filtered seawater.
Dissection
Separation
of the
endoderm
Culture
set-up