Microscopy medium

Recipe

Reagent	Amount to add (for 1 L)	Final concentration
NaCl	8000 mg	137 mM
KCl	400 mg	5.4 mM
CaCl₂•2H₂O	264 mg	1.8 mM
MgSO₄•7H₂O	200 mg	0.8 mM
D-Glucose•H₂O	4000 mg	20 mM
H₂O	to 980 mL

Sterilize the solution of salt and sugar above by autoclaving.
Prepare fresh 1 M HEPES by dissolving 23.8 g of HEPES in 75 mL of H₂O.
Add approximately six solid NaOH pellets to the 1 M HEPES to obtain a pH of 7.4. Adjust the volume to 100 mL, control pH, and filter sterilize.
Add 20 mL of the 1 M HEPES buffer to the salt-and-sugar solution to obtain the microscopy medium. This solution can be kept (sterile) at 4°C for months.