Freeze-Substitution Fixative for Yeast (2)

METHOD

• 1. Working under a fume hood, prepare a 20% solution of paraformaldehyde in anhydrous methanol.

  • Paraformaldehyde powder is not soluble in acetone.

• 2. Cover beaker. Heat gently to ∼70°C with mixing on a heated stir plate until condensation forms around the upper edges of the beaker.

• 3. Add ∼1/4–1/2 a pellet of NaOH until the solution clears.

• 4. Dilute to 2%–4% with acetone.

• 5. Add glutaraldehyde to 0.1%.