X-Message-Number: 9190 Date: Mon, 23 Feb 1998 01:44:57 -0800 (PST) From: Doug Skrecky <> Subject: testing cryoprotectants with flies Goal: Test the effect of various cryoprotectants on the freeze/thaw survival of drosophilia melanogaster flies. Procedure: Add cryoprotectant to commercial 4-24 fly food. Feed this to flies for several days. Then freeze the flies overnight in refrigerators's freezer. Thaw the next day and look for survivors. Note: With glycerol half the water added to the fly food was replaced by this liquid. With the other cryoprotectants, which are solid at room temperature, equal volumes of cryoprotectant and 4-24 fly food were mixed together, prior to addition of water. Results: Toxicity of cryoprotectant was roughly judged based on mortality prior to freezing. Based on this the substances used can be ranked in order of decreasing toxicity as follows: alanine, glycine > glycerol, proline > glucose, glutamine. Percentage survival after freezing/thawing is as follows: alanine: 0% glucose: 0 glutamine: 0 glycerol: 0 glycine: 0 proline: 0 Conclusions: Drosophilia melanogaster is not an appropriate experimental model for testing cryoprotectants. Possibly a more freeze resistant insect might be useful for ranking the effectiveness of various cryoprotectants. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9190