Thermal sensitivity of cell metabolism of different Antarctic fish species mirrors organism temperature tolerance
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ORIGINAL PAPER
Thermal sensitivity of cell metabolism of different Antarctic fish species mirrors organism temperature tolerance Gisela Lannig1 · Anette Tillmann1 · Sarah Howald1 · Laura S. Stapp2 Received: 11 December 2019 / Revised: 14 September 2020 / Accepted: 16 September 2020 / Published online: 30 September 2020 © The Author(s) 2020
Abstract Despite cold adaptation, Antarctic fish show lower growth than expected from the van’t Hoff’s Q10 rule. Protein synthesis is one of the main energy-consuming processes, which is downregulated under energy deficiency. Considering the effect of temperature on growth performance, we tested if temperature-dependent cellular energy allocation to protein synthesis correlates with temperature-dependent whole-animal growth and thus thermal tolerance. Cell respiration and energy expenditure for protein synthesis were determined in hepatocytes of the circumpolar-distributed Antarctic eelpout Pachycara brachycephalum after warm acclimation (0 °C vs 5 °C) and, of two notothenioids the sub-Antarctic Lepidonotothen squamifrons and the high-Antarctic icefish Chionodraco hamatus. We used intermittent-flow respirometry to analyse cellular response to acute warming from 5 to 10 °C (P. brachycephalum) and from 1 to 5 °C (L. squamifrons, C. hamatus). Warming-induced rise in respiration was similar between 0- and 5 °C-acclimated P. brachycephalum and between L. squamifrons and C. hamatus. Irrespective of acclimation, warming decreased energy expenditure for protein synthesis in P. brachycephalum, which corresponds to reduced whole-animal growth at temperatures > 5 °C. Warming doubled energy expenditure for protein synthesis in L. squamifrons but had no effect on C. hamatus indicating that L. squamifrons might benefit from warmer waters. The species-specific temperature effect on energy expenditure for protein synthesis is discussed to mirror thermal sensitivity of whole-animal growth performance, thereby paralleling the degree of cold adaptation. Clearly more data are necessary including measurements at narrower temperature steps particularly for C. hamatus and an increased species’ number per ecotype to reinforce presented link between cellular and whole-animal thermal sensitivity. Keywords Temperature · Polar · Icefish · Cell respiration · Cycloheximide · Protein synthesis
Introduction The development of the Antarctic Circumpolar Current and the resulting isolation and cooling of the Southern Ocean created the coldest marine environment. Antarctic waters are characterized by temperatures as low as − 1.9 °C with little seasonal variations and high oxygen content. The Antarctic Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00300-020-02752-w) contains supplementary material, which is available to authorized users. * Gisela Lannig [email protected] 1
Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Center for Polar & Marine Research, 27570 Bremerhaven, Germany
Australian Institute of Marine Science, Darwin, NT 08
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