Nitrogen-Deprived Minimal Sporulation Liquid (MSL–N) Medium

Recipe

Reagent	Quantity (for 1 L)	Final concentration
Glucose	10 g	55.5 mm
KH₂PO₄	1 g	7.3 mm
NaCl	0.1 g	1.7 mm
MgSO₄ · 7H₂O	0.2 g	0.81 mm
CaCl₂ · 6H₂O (0.1 m)	1 mL	0.1 mm
Minerals (10,000×)	0.1 mL	1×
Vitamins (1000×)	1 mL	1×
H₂O	to 1 L
Filter-sterilize using a 0.22-µm pore size membrane. (For live cell imaging, filter-sterilized medium has lower background fluorescence than autoclaved medium.) Store at 4°C. (We recommend use of prototrophic strains. Even when using auxotrophic strains, we do not normally add amino acid supplements.)