Scanning electron microscope image of Strongylocentrotus drobachiensus [sea urchin] embryo at the late gastrula stage. This high magnification image of the embryo shows the primary mesenchyme syncytial ring, where it attaches to the outer epithelial layer (ectoderm layer). The fine fibers are part of the blastocoel matrix. The primary mesenchyme syncytial ring is the precursor to spicule formation (developing calcareous larval skeleton). 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 morphogenesis
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