(Source: R. Warga from Zebrafish Book 5th Edition)
For a slightly less rigid mounting medium, use a lower concentration of Agarose (0.1%) or 3% methyl cellulose (Sigma M-0387). Methyl cellulose is especially good for orienting young embryos (less than 10 hpf old).
1. Apply a drop of 3% methyl cellulose in Embryo Medium to a depression slide.
2. Suck an embryo up into a Pasteur pipette and position it near the opening in the pipette.
3. Plunge the pipette into the methyl cellulose and gently expel the embryo with as little medium as possible. The medium around the embryo will be quickly absorbed into the methyl cellulose.
4. Use a fine loop of nylon fishing line to orient the embryo.
5. Place a drop of saline over the well to keep the preparation from drying out and getting too sticky.
6. To release the embryo, drop the entire slide into Embryo Medium for a few minutes. The methyl cellulose will absorb the medium and become very soft so that the embryo can be teased free with the nylon loop.
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