Experiment: Elevated temperature and PCO2 affect enzyme activities in differentially oxidative tissues of Notothenia rossii

DOI

Mitochondrial plasticity plays a central role in setting the capacity for acclimation of aerobic metabolism in ectotherms in response to environmental changes. We still lack a clear picture if and to what extent the energy metabolism and mitochondrial enzymes of Antarctic fish can compensate for changing temperatures or PCO2 and whether capacities for compensation differ between tissues. We therefore measured activities of key mitochondrial enzymes (citrate synthase (CS), cytochrome c oxidase (COX)) from heart, red muscle, white muscle and liver in the Antarctic fish Notothenia rossii after warm- (7 °C) and hypercapnia- (0.2 kPa CO2) acclimation vs. control conditions (1 °C, 0.04 kPa CO2). In heart, enzymes showed elevated activities after cold-hypercapnia acclimation, and a warm-acclimation-induced upward shift in thermal optima. The strongest increase in enzyme activities in response to hypercapnia occurred in red muscle. In white muscle, enzyme activities were temperature-compensated. CS activity in liver decreased after warm-normocapnia acclimation (temperature-compensation), while COX activities were lower after cold- and warm-hypercapnia exposure, but increased after warm-normocapnia acclimation. In conclusion, warm-acclimated N. rossii display low thermal compensation in response to rising energy demand in highly aerobic tissues, such as heart and red muscle. Chronic environmental hypercapnia elicits increased enzyme activities in these tissues, possibly to compensate for an elevated energy demand for acid-base regulation or a compromised mitochondrial metabolism, that is predicted to occur in response to hypercapnia exposure. This might be supported by enhanced metabolisation of liver energy stores. These patterns reflect a limited capacity of N. rossii to reorganise energy metabolism in response to rising temperature and PCO2.

Notothenia rossii acclimated to higher temperature and PCO2; Citrate synthase (CS) and cytochrome c oxidase (COX) activities are given in nmol per minute and mg protein (CS/protein; COX/protein) or mg tissue fresh mass (CS/MW; COX/MW) at the assay temperatures of 0, 6, 9, 12 °C in heart, liver, red muscle & white muscle tissue of all acclimated animals and the control.

Supplement to: Strobel, Anneli; Leo, Elettra; Pörtner, Hans-Otto; Mark, Felix Christopher (2013): Elevated temperature and PCO2 shift metabolic pathways in differentially oxidative tissues of Notothenia rossii. Comparative Biochemistry and Physiology Part B: Biochemistry & Molecular Biology, 166(1), 48-57

Identifier
DOI https://doi.org/10.1594/PANGAEA.829831
Related Identifier https://doi.org/10.1016/j.cbpb.2013.06.006
Related Identifier https://doi.org/10.1594/PANGAEA.831182
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.829831
Provenance
Creator Strobel, Anneli; Leo, Elettra; Pörtner, Hans-Otto ORCID logo; Mark, Felix Christopher ORCID logo
Publisher PANGAEA
Publication Year 2014
Funding Reference German Research Foundation https://doi.org/10.13039/501100001659 Crossref Funder ID 5472008 https://gepris.dfg.de/gepris/projekt/5472008 Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 2003 data points
Discipline Earth System Research
Spatial Coverage (-58.667 LON, -62.233 LAT); Potter Cove, King George Island, Antarctic Peninsula