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.
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.