title: A comparison of the metabolic cost of protein synthesis in stenothermal and eurythermal isopod crustaceans.
abstract: To examine the presence of metabolic cold adaptation in Antarctic isopods, whole animal rates of oxygen uptake (MVo2) and protein synthesis were measured in Glyptonotus antarcticus at 0 degree C and compared with the temperature isopod Idotea rescata at 4 and 14 degrees C. The specific relationship between rates of metabolism and protein synthesis was investigated by injecting animals with cycloheximide, a protein synthesis inhibitor. In G. antarcticus, routine MVo2 was 11.10 +/- 0.89 mumol.kg-1.min-1 (n = 19 animals), and ks was 0.24 +/- 0.04% protein synthesized/day (n = 8 animals). Comparison with I. rescata showed that standardized whole animal MVo2 decreased with temperature (temperature quotient = 1.99), but whole animal ks was considerably lower in the Antarctic isopod; 66 and 22% of total MVo2 was attributable to protein synthesis in G. antarcticus at 0 degree C and I. rescata at 4 degrees C, respectively. The energetic cost of protein synthesis was four times higher in G. antarcticus at 885 +/- 141 mmol ATP/g protein (n = 5 animals) compared with 237 +/- 76 mmol ATP/g protein (n = 6) in I. rescata. G. antarcticus does not show metabolic rate compensation and maintains extremely low ks levels because of the relatively high energetic cost of protein synthesis.
authors.affiliation: School of Biological Sciences, University of Birmingham, United Kingdom.
authors.forename: N M
authors.initials: NM
authors.lastname: Whiteley
authors.forename: E W
authors.initials: EW
authors.lastname: Taylor
authors.forename: A J
authors.initials: AJ
authors.lastname: el Haj
mesh_terms: D000064:Acclimatization; D000818:Animals; D000864:Antarctic Regions; D003080:Cold Temperature; D003445:Crustacea / Q000378:metabolism*; D003513:Cycloheximide / Q000494:pharmacology; D004734:Energy Metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
chemical_list: D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide