Worm Breeder's Gazette 4(1): 14

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Method to Freeze a Large Number of C. elegans Stocks

K. Lew, J. Miwa

Figure 1

Strains are grown on two to three 100 mm Petri plates until bacteria 
are nearly exhausted and a large population of L1 and L2 animals are 
present.  The animals are washed from the plates in a 50:50 mixture of 
M9 buffer (or M9 medium) and B medium to a volume usually of 2.5 to 5 
ml.  Equal aliquots are placed into freezing vials.  (Two ml plastic 
screw top vials of 38x12.5 mm are found to be convenient.) The vials 
are placed into a box made of good insulating material, e.g., 
polystyrene foam, bored with holes that snugly fit the vials, so that 
freezing may proceed at no more than 1 C per minute.
[See Figure 1]
The box is then put into a freezer of -80 C or lower for several 
hours before vials are finally stored in a liquid N2 tank.  If a gas 
phase liquid N2 tank is available, the box may be placed there with or 
without prior freezing in a freezer.
This method allows freezing of hundreds of vials at a time.
B medium: per liter, 5.7 g NaCl; 50 ml KH2PO4 (1M, pH6.0); 300 ml 
Glycerol (100%); 650 ml distilled water.

Figure 1