Sheilds and Sang M3 Medium is based on the original formula of D22 medium.

• Supports the growth of cells derived from Drosophila melanogaster
• Formulation also includes Bis-Tris
• Prevents rapid shifts in pH
• Enough to make 5 L

The medium supports the growth of cells derived from Drosophila melanogaster. Sheilds and Sang (1977) eliminated chloride salts present in the previous formulation and introduced potassium and sodium ions in the form of glutamate salts. They replaced lactalbumin hydrolysate with individual amino acids and retained yeast extract. The formulation also includes Bis-Tris, an organic buffer which prevents rapid shifts in pH.