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,
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Take an autoclaved sterile 250 mL bottle.
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Add 1 g of powdered cholesterol (VWR Cat #0433-250G) to the bottle.
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Add 200 mL of 100% ethanol to the bottle.
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Cap and shake to resuspend.
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Store at room temperature on the reagents shelf for up to six months.