How to Make Cholesterol
Note: C. elegans requires cholesterol to progress through the four larval stages. The Andersen lab found that some filters were removing cholesterol from K medium and S medium. Most worms arrested in larval development. For this reason, we add cholesterol after filtration or autoclaving of media for NGMA plates.
For NGM/HGM plates: Use the unfiltered but sterile 5 mg/mL cholesterol in ethanol.
To make this cholesterol,
Take an autoclaved sterile 250 mL bottle.
Add 1 g of powdered cholesterol (VWR Cat #0433-250G) to the bottle.
Add 200 mL of 100% ethanol to the bottle.
Cap and shake to resuspend.
Store at room temperature on the reagents shelf for up to six months.