title: Biochemical acclimation of metabolic enzymes in response to lowered temperature in tadpoles of Limnodynastes peronii.
abstract: We measured the rate at which the metabolic enzymes lactate dehydrogenase (LDH), citrate synthase (CS), and cytochrome c oxidase (CCO) acclimate in the response to lowered temperature in the axial muscle of tadpoles of Limnodynastes peronii (Anura: Myobatrachidae) over 6 weeks. In addition, we measured growth rates of the tadpoles kept at both temperatures and examined the activities of these enzymes in the liver tissue of the control group and cold-acclimated group at the end of the experiment. We found that LDH acclimates in axial muscle; the differences between the control and cold-acclimated group became apparent after 21 days. After 42 days, the activity of LDH in axial muscle in the cold-acclimated group was 30% greater than the control group. Growth rates were maintained at 0.7 mm/week within both treatments despite the 10 degrees C difference in temperature between experimental groups. Both LDH and CS were increased in activity in the liver (5 and 1.3 times greater, respectively, in the cold-acclimated group). The thermal sensitivity (Q(10)) of LDH was between 20 and 30 degrees C in the cold-acclimated group (1.2+/-0.01) when compared to the control group (1.6+/-0.15). The rate at which acclimation in this species occurs is appropriate for seasonal changes in temperature, and these animals may not be able to respond to a rapid drop in temperature.
authors.affiliation: School of Biological Sciences A08, The University of Sydney, NSW 2006, Australia. krogers@bio.usyd.edu.au
authors.forename: Kris D
authors.initials: KD
authors.lastname: Rogers
authors.forename: Frank
authors.initials: F
authors.lastname: Seebacher
authors.forename: Michael B
authors.initials: MB
authors.lastname: Thompson
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D001001:Anura / Q000033:anatomy & histology / Q000254:growth & development* / Q000378:metabolism*; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003080:Cold Temperature; D003576:Electron Transport Complex IV / Q000378:metabolism; D042844:L-Lactate Dehydrogenase (Cytochrome) / Q000378:metabolism; D007814:Larva / Q000201:enzymology; D008099:Liver / Q000201:enzymology
chemical_list: D042844:L-Lactate Dehydrogenase (Cytochrome); D003576:Electron Transport Complex IV; D002950:Citrate (si)-Synthase