title: Cold tolerance and freeze-induced glucose accumulation in three terrestrial slugs.
abstract: Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about -4 °C when cooled under dry conditions, but freezing of body fluids was readily induced at -1 °C when in contact with external ice crystals. All three species survived freezing for 2 days at -1 °C, and some A. rufus and A. lusitanicus also survived freezing at -2 °C. (1)H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 μg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates.
authors.affiliation: Department of Agroecology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark. stsl@dmu.dk
authors.forename: Stine
authors.initials: S
authors.lastname: Slotsbo
authors.forename: Lars Monrad
authors.initials: LM
authors.lastname: Hansen
authors.forename: Kurt
authors.initials: K
authors.lastname: Jordaens
authors.forename: Thierry
authors.initials: T
authors.lastname: Backeljau
authors.forename: Anders
authors.initials: A
authors.lastname: Malmendal
authors.forename: Niels Chr
authors.initials: NC
authors.lastname: Nielsen
authors.forename: Martin
authors.initials: M
authors.lastname: Holmstrup
mesh_terms: D000064:Acclimatization; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001833:Body Temperature Regulation; D003080:Cold Temperature; D003451:Cryoprotective Agents / Q000378:metabolism; D017753:Ecosystem; D004734:Energy Metabolism; D005285:Fermentation; D005615:Freezing; D049851:Gastropoda / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006458:Hemolymph / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D055432:Metabolomics / Q000379:methods; D019802:Succinic Acid / Q000378:metabolism; D013997:Time Factors; D044366:Transition Temperature
chemical_list: D003451:Cryoprotective Agents; D019344:Lactic Acid; D000255:Adenosine Triphosphate; D019802:Succinic Acid; D005947:Glucose