Scanning electron microscope image of Lytechinus pictus [sea urchin] embryo at the 16-cell stage. The four large macromeres are behind the four small micromeres. The eight mesomeres are behind the macromeres. Remnants of the fertilization envelope can be seen attached to some of the cells. This image is part of a group of SEM images of sea urchin embryos at various stages of development. The group is available as CIL:39782-39791.
Biological Process: Embryonic cleavage, Embryo development
Images taken on a JEOL 35C SEM.
1. 2% GTA in 75% MBL SW or FilteredSW
FSW - fix for 1.5hrs. RT.
2. Rinse with 0.1M NaCacodylate buffer pH 7.4
3. 0.5% OSO4 in .075M NaCacodylate buffer pH 7.4 - 30' in the cold
4. Rinse in 0.1M NaCacodylate buffer ph 7.4
5. Dehydrate thru ETOH: 30%, 50%, 70%, 95% for 5 min each
6. 100% - 3 changes - 15' each
7. Critical Point Dry
8. Stick embryos down onto silver paint. Gently crack open with glass needle (pipette drawn out to a fine point).
9. Sputter coat with AuPd.
Author: Louisa Howard
Source: The Cell: An Image Library