Worm Breeder's Gazette 12(3): 11b (June 15, 1992)
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.
In the course of the study described above, we developed a simple and quick method for isolating wild nematodes from soil. This procedure is based on John Sulston's sucrose flotation method for isolating C. elegans from bacteria and crud. Mix roughly 50 g of soil with 100 ml of water in a 200 ml beaker by swirling. Remove 15 ml of the middle muck to 15 ml clear conical centrifuge tubes. Avoid the rocks that have fallen to the bottom and the bits of wood and leaves that have risen to the top of the beaker. Let the muck settle in the conical tubes for 30 seconds. Again remove 7 ml of the middle muck from each tube to clean 15 ml centrifuge tubes. To each tube add 7 ml of ice cold 60% (w/w) sucrose (to a final concentration of 30% sucrose), mix well by rapidly shaking the tubes and immediately centrifuge at 2,000 rpm for 2 min. During this step the nematodes float to the top of the tube and almost all of the soil sinks to the bottom of the tube. Transfer the top 1.0 ml of solution from each tube into fresh tubes and dilute the sucrose with 14 mls of cold water. Mix well by inverting the tube 5-10 times and centrifuge at 2,000 rpm for 2 min. The nematodes will be concentrated in the pellet and can be easily transferred to NGM plates with a pipet. We typically obtain 5-20 animals from each tube. Some nematode species will survive well on NGM plates; others will grow very slowly or die.