title: Depression of protein synthesis during diapause in embryos of the annual killifish Austrofundulus limnaeus.
abstract: Rates of protein synthesis are substantially depressed in diapause II embryos of Austrofundulus limnaeus. Inhibition of oxygen consumption and heat dissipation with cycloheximide indicates that 36% of the adenosine triphosphate (ATP) turnover in prediapausing embryos (8 d postfertilization [dpf]) is caused by protein synthesis; the contribution of protein synthesis to ATP turnover in diapause II embryos is negligible. In agreement with the metabolic data, incorporation of amino acids (radiolabeled via (14)CO(2)) into perchloric acid-precipitable protein decreases by over 93% in diapause II embryos compared with embryos at 8 dpf. This result represents a 36% reduction in energy demand because of depression of protein synthesis during diapause. Adjusting for changes in the specific radioactivity of the free amino acid pool at the whole-embryo level yields rates of protein synthesis that are artifactually high and not supportable by the observed rates of oxygen consumption and heat dissipation during diapause. This result indicates a regionalized distribution of labeled amino acids likely dictated by a pattern of anterior to posterior cell cycle arrest. AMP/ATP ratios are strongly correlated with the decrease in rates of protein synthesis, which suggests a role for adenosine monophosphate (AMP) in the control of anabolic processes. The major depression of protein synthesis during diapause II affords a considerable reduction in energy demand and extends the duration of dormancy attainable in these embryos.
authors: Section of Integrative Physiology and Neurobiology, Department of Environmental, Population, and Organismic Biology, University of Colorado, Boulder, CO 80309-0334, USA. podrabsk@leland.stanford.edu
authors: J E
authors: JE
authors: Podrabsky
authors: S C
authors: SC
authors: Hand
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004734:Energy Metabolism / Q000187:drug effects; D006358:Hot Temperature; D007695:Killifishes / Q000196:embryology*; D010101:Oxygen Consumption / Q000187:drug effects; D014176:Protein Biosynthesis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide