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Spahni R., Chappellaz J., Stocker T., Loulergue L., Hausammann G., Kawamura K., Fluckiger J., Schwander J., Raynaud D., Masson-Delmotte V. & Jouzel J. (2005). Atmospheric Methane and Nitrous Oxide of the Late Pleistocene from Antarctic Ice Cores. Science, 310, 1317–1321.
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Lea M.A., Guinet C., Cherel Y., Duhamel G., Dubroca L., Pruvost P. & Hindell M. (2006). Impacts of climatic anomalies on provisioning strategies of a Southern Ocean predator. Mar. Ecol. Prog. Ser., 310, 77–94.
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Masson-Delmotte, V. , Jouzel, J., Landais, A., Stievenard, M. , Johnsen, S.J. , White, J.W.C. , Sveinbjornsdottir, A. , Fuhrer, K.,. (2005). Deuterium excess reveals millennial and orbital scale fluctuations of Greenland moisture origin. Science, 309, 118–121.
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Masson-Delmotte, V.; Jouzel, J.; Landais, A.; Stievenard, M.; Johnsen, S.J.; White, J.W.C.; Werner, M.; Sveinbjornsdottir, A.; Fuhrer, K. (2005). GRIP Deuterium Excess Reveals Rapid and Orbital-Scale Changes in Greenland Moisture Origin. Science, 309(5731), 118–121.
Abstract: The Northern Hemisphere hydrological cycle is a key factor coupling ice sheets, ocean circulation, and polar amplification of climate change. Here we present a Northern Hemisphere deuterium excess profile covering one climatic cycle, constructed with the use of {delta}18O and {delta}D Greenland Ice Core Project (GRIP) records. Past changes in Greenland source and site temperatures are quantified with precipitation seasonality taken into account. The imprint of obliquity is evidenced in the site-to-source temperature gradient at orbital scale. At the millennial time scale, GRIP source temperature changes reflect southward shifts of the geographical locations of moisture sources during cold events, and these rapid shifts are associated with large-scale changes in atmospheric circulation.
Programme: 458
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. (2006). Locomotion and foraging strategy in foot-propelled and wing-propelled shallow-diving seabirds. Mar. Ecol. Prog. Ser., 308, 293–301.
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Lescroel, A. & Bost, C.A. (2005). Foraging under contrasted oceanographic conditions: the Gentoo Penguin at Kerguelen Archipelago. Mar. Ecol. Prog. Ser., 302, 245–261.
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Caillon N., Severinghaus J.P., Jouzel J., Barnola J.M., Kang J. & Lipenkov V.Y. (2003). Timing of Atmospheric CO2 and Antarctic Temperature Changes across Termination III. Science, 299, 1728–1731.
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Raccurt, M.; Baudimont, F.; Tirard, J.; Rey, B.; Moureaux, E.; Geloen, A.; Duchamp, C. (2008). Growing in Antarctica, a challenge for white adipose tissue development in Adelie penguin chicks (Pygoscelis adeliae). Am. J. Physiol. Regul. Integr. Comp. Physiol., 295(5), R1671–1679.
Abstract: Rapid growth is of crucial importance for Adelie penguin chicks reared during the short Antarctic summer. It partly depends on the rapid ontogenesis of fat stores that are virtually null at hatching but then develop considerably (x40) within a month to constitute both an isolative layer against cold and an energy store to fuel thermogenic and growth processes. The present study was aimed at identifying by RT-PCR the major transcriptional events that chronologically underlie the morphological transformation of adipocyte precursors into mature adipocytes from hatching to 30 days of age. The peak expression of GATA binding protein 3, a marker of preadipocytes, at day 7 posthatch indicates a key proliferation step, possibly in relation to the expression of C/EBP{alpha} (C/EBP{alpha}). High plasma total 3,5,3'-triiodo-L-thyronine (T3) levels and high levels of growth hormone receptor transcripts at hatching suggested that growth hormone and T3 play early activating roles to favor proliferation of preadipocyte precursors. Differentiation and growth of preadipocytes may occur around day 15 in connection with increased abundance of transcripts encoding IGF-1, proliferator-activated receptor-{gamma}, and C/EBP{beta}, gradually leading to functional maturation of metabolic features of adipocytes including lipid uptake and storage (lipoprotein lipase, fatty-acid synthase) and late endocrine functions (adiponectin) by day 30. Present results show a close correlation between adipose tissue development and chick biology and a difference in the scheduled expression of regulatory factors controlling adipogenesis compared with in vitro studies using cell lines emphasizing the importance of in vivo approaches.
Programme: 131
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Rey, B.; Halsey, L.G.; Dolmazon, V.; Rouanet, J.-L.; Roussel, D.; Handrich, Y.; Butler, P.J.; Duchamp, C. (2008). Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins. Am J Physiol Regul Integr Comp Physiol, 295(1), R92–100.
Abstract: In endotherms, regulation of the degree of mitochondrial coupling affects cell metabolic efficiency. Thus it may be a key contributor to minimizing metabolic rate during long periods of fasting. The aim of the present study was to investigate whether variation in mitochondrial avian uncoupling proteins (avUCP), as putative regulators of mitochondrial oxidative phosphorylation, may contribute to the ability of king penguins (Aptenodytes patagonicus) to withstand fasting for several weeks. After 20 days of fasting, king penguins showed a reduced rate of whole animal oxygen consumption ([IMG]f1.gif“ ALT=”V“ BORDER=”0“>O2; -33%) at rest, together with a reduced abundance of avUCP and peroxisome proliferator-activated receptor-{gamma} coactivator-1{alpha} (PGC1-{alpha}) mRNA in pectoralis muscle (-54%, -36%, respectively). These parameters were restored after the birds had been refed for 3 days. Furthermore, in recently fed, but not in fasted penguins, isolated muscle mitochondria showed a guanosine diphosphate-inhibited, fatty acid plus superoxide-activated respiration, indicating the presence of a functional UCP. It was calculated that variation in mitochondrial UCP-dependent respiration in vitro may contribute to nearly 20% of the difference in resting [IMG]f1.gif” ALT=“V” BORDER=“0”>O2 between fed or refed penguins and fasted penguins measured in vivo. These results suggest that the lowering of avUCP activity during periods of long-term energetic restriction may contribute to the reduction in metabolic rate and hence the ability of king penguins to face prolonged periods of fasting.
Programme: 131;394
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. (2001). An Oceanic Cold Reversal during the Last Deglaciation. Science, 293, 2074–2077.
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