title: Evidence that high pCO2 affects protein metabolism in tropical reef corals.
abstract: Early life stages of the coral Seriatopora caliendrum were used to test the hypothesis that the depression of dark respiration in coral recruits by high pCO2 is caused by perturbed protein metabolism. First, the contribution of protein anabolism to respiratory costs under high pCO2 was evaluated by measuring the aerobic respiration of S. caliendrum recruits with and without the protein synthesis inhibitor emetine following 1 to 4 days at 45 Pa versus 77 Pa pCO2. Second, protein catabolism under high pCO2 was evaluated by measuring the flux of ammonium (NH4 (+)) from juvenile colonies of S. caliendrum incubated in darkness at 47 Pa and 90 Pa pCO2. Two days after settlement, respiration of recruits was affected by an interaction between emetine and pCO2, with emetine reducing respiration 63% at 45 Pa pCO2 and 27% at 77 Pa pCO2. The interaction disappeared 5 days after settlement, when respiration was reduced 27% by emetine under both pCO2 conditions. These findings suggest that protein anabolism accounted for a large proportion of metabolic costs in coral recruits and was affected by high pCO2, with consequences detected in aerobic respiration. Juvenile S. caliendrum showed net uptake of NH4 (+) at 45 Pa pCO2 but net release of NH4 (+) at 90 Pa pCO2, indicating that protein catabolism, NH4 (+) recycling, or both were affected by high pCO2. Together, these results are consistent with the hypothesis that high pCO2 affects protein metabolism in corals.
authors.affiliation: Department of Biology, California State University, 18111 Nordhoff Street, Northridge, California 91330-8303; and peter.edmunds@csun.edu.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Edmunds
authors.affiliation: Department of Biology, California State University, 18111 Nordhoff Street, Northridge, California 91330-8303; and University of Hawai'i at Mānoa, Hawai'i Institute of Marine Biology, PO Box 1346, Kaneohe, Hawaii 96744.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Wall
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000187:drug effects* / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology*; D057894:Coral Reefs; D004640:Emetine / Q000494:pharmacology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism*; D012119:Respiration / Q000187:drug effects; D013624:Taiwan
chemical_list: D011500:Protein Synthesis Inhibitors; D011506:Proteins; D002245:Carbon Dioxide; D004640:Emetine