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Talbot, D.A.; Duchamp, C.; Rey, B.; Hanuise, N.; Rouanet, J.L.; Sibille, B.; Brand, M.D. (2004). Uncoupling protein and ATP/ADP carrier increase mitochondrial proton conductance after cold adaptation of king penguins. J. Physiol. (Lond.), 558(1), 123–135.
Abstract: Juvenile king penguins develop adaptive thermogenesis after repeated immersion in cold water. However, the mechanisms of such metabolic adaptation in birds are unknown, as they lack brown adipose tissue and uncoupling protein-1 (UCP1), which mediate adaptive non-shivering thermogenesis in mammals. We used three different groups of juvenile king penguins to investigate the mitochondrial basis of avian adaptive thermogenesis . Skeletal muscle mitochondria isolated from penguins that had never been immersed in cold water showed no superoxide-stimulated proton conductance, indicating no functional avian UCP. Skeletal muscle mitochondria from penguins that had been either experimentally immersed or naturally adapted to cold water did possess functional avian UCP, demonstrated by a superoxide-stimulated, GDP-inhibitable proton conductance across their inner membrane. This was associated with a markedly greater abundance of avian UCP mRNA. In the presence (but not the absence) of fatty acids, these mitochondria also showed a greater adenine nucleotide translocase-catalysed proton conductance than those from never-immersed penguins. This was due to an increase in the amount of adenine nucleotide translocase. Therefore, adaptive thermogenesis in juvenile king penguins is linked to two separate mechanisms of uncoupling of oxidative phosphorylation in skeletal muscle mitochondria: increased proton transport activity of avian UCP (dependent on superoxide and inhibited by GDP) and increased proton transport activity of the adenine nucleotide translocase (dependent on fatty acids and inhibited by carboxyatractylate).
Programme: 131
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Benjamin Rey, Claude Duchamp, Damien Roussel. (2017). Uncoupling effect of palmitate is exacerbated in skeletal muscle mitochondria of sea-acclimatized king penguins (Aptenodytes patagonicus) (Vol. 211).
Abstract: In king penguin juveniles, the environmental transition from a terrestrial to a marine habitat, occurring at fledging, drastically stimulates lipid catabolism and the remodelling of muscle mitochondria to sustain extensive swimming activity and thermoregulation in the cold circumpolar oceans. However, the exact nature of these mechanisms remains only partially resolved. Here we investigated, in vitro, the uncoupling effect of increasing doses of fatty acids in pectoralis muscle intermyofibrillar mitochondria isolated, either from terrestrial never-immersed or experimentally cold water immersed pre-fledging king penguins or from sea-acclimatized fledged penguins. Mitochondria exhibited much greater palmitate-induced uncoupling respiration and higher maximal oxidative capacity after acclimatization to marine life. Such effects were not reproduced experimentally after repeated immersions in cold water, suggesting that the plasticity of mitochondrial characteristics may not be primarily driven by cold exposure per se but by other aspects of sea acclimatization.
Keywords: Bioenergetics Birds Free fatty acids Mitochondria Muscle
Programme: 131
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Yann Tremblay, Yves Cherel, Marc Oremus, Torkild Tveraa and Olivier Chastel. (2003). Unconventional ventral attachment of time-depth recorders as a new method for investigating time budget and diving behaviour of seabirds. J. Exp. Biol., 206, 1929–1940.
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Christopher S. Watson, Neil J. White, John A. Church, Matt A. King, Reed J. Burgette, Benoit Legresy. (2015). Unabated global mean sea-level rise over the satellite altimeter era (Vol. 5).
Abstract: The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability1, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1 (refs 2, 3). However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift4,5). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). In contrast to previous results (for example, refs 6, 7), we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions2, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied (updated from ref. 8) and reprocessed ERS-2/Envisat altimetry9. Second, in contrast to the previously reported slowing in the rate during the past two decades1, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections2,10, and larger than the twentieth-century acceleration2,8,10.
Programme: 688
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Christopher S. Watson, Neil J. White, John A. Church, Matt A. King, Reed J. Burgette, Benoit Legresy. (2015). Unabated global mean sea-level rise over the satellite altimeter era (Vol. 5).
Abstract: The rate of global mean sea-level (GMSL) rise has been suggested to be lower for the past decade compared with the preceding decade as a result of natural variability1, with an average rate of rise since 1993 of +3.2 ± 0.4 mm yr−1 (refs 2, 3). However, satellite-based GMSL estimates do not include an allowance for potential instrumental drifts (bias drift4,5). Here, we report improved bias drift estimates for individual altimeter missions from a refined estimation approach that incorporates new Global Positioning System (GPS) estimates of vertical land movement (VLM). In contrast to previous results (for example, refs 6, 7), we identify significant non-zero systematic drifts that are satellite-specific, most notably affecting the first 6 years of the GMSL record. Applying the bias drift corrections has two implications. First, the GMSL rate (1993 to mid-2014) is systematically reduced to between +2.6 ± 0.4 mm yr−1 and +2.9 ± 0.4 mm yr−1, depending on the choice of VLM applied. These rates are in closer agreement with the rate derived from the sum of the observed contributions2, GMSL estimated from a comprehensive network of tide gauges with GPS-based VLM applied (updated from ref. 8) and reprocessed ERS-2/Envisat altimetry9. Second, in contrast to the previously reported slowing in the rate during the past two decades1, our corrected GMSL data set indicates an acceleration in sea-level rise (independent of the VLM used), which is of opposite sign to previous estimates and comparable to the accelerated loss of ice from Greenland and to recent projections2,10, and larger than the twentieth-century acceleration2,8,10.
Programme: 688
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Teulé M. (2005). Un test de la Starvation Resistance Hypothesis “ chez un Diptère subantarctique : Anatalanta aptera.”.
Abstract: Master 2 Ecologie – Ethologie – Evolution Université de Rennes 1
Programme: 136
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Moreau M., Mercier D. & Laffly D. (2004). Un siècle de dynamiques paraglaciaires et végétales au Svalbard Midre Lovénbreen Spitsberg nord-occidental. Géomorphologie : relief, processus, environnement, 2, 157–168.
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Gómez Coutouly, Yan Axel. (2021). Un peuplement antérieur à 20 000 ans en Amérique ? Le caractère anthropique des sites de Pedra Furada (Brésil) en question (Vol. 118).
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Yan Axel Gomez Coutouly. (2021). Un peuplement antérieur à 20 000 ans en Amérique ? Bachelor's thesis, , .
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J.P. Braly. (2008). Un océan et des poussières….
Abstract: Début novembre, deux chercheurs embarqueront pour « l’archipel de la désolation ». Objectif : étudier les micronutriments apportés par l’air des continents, indispensables aux microalgues pompant le CO2 issu de l’atmosphère.
Journal du CNRS
Programme: 1188
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