Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS
The hypothesis of an oxygen limited thermal tolerance was tested in the Antarctic teleost Pachycara brachycephalum. Using flow-through respirometry, in vivo 31P-NMR spectroscopy and MRI, we studied energy metabolism, intracellular pH (pHi), blood-flow and oxygenation between 0 and 13°C under normoxi...
Published in: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology |
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ftawi:oai:epic.awi.de:5676 2023-09-05T13:15:21+02:00 Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS Mark, Felix Christopher Bock, Christian Pörtner, Hans-Otto 2002 application/pdf https://epic.awi.de/id/eprint/5676/ https://epic.awi.de/id/eprint/5676/1/Mar2002c.pdf https://doi.org/10.1152/ajpregu.00167.2002 https://hdl.handle.net/10013/epic.16239 https://hdl.handle.net/10013/epic.16239.d001 unknown https://epic.awi.de/id/eprint/5676/1/Mar2002c.pdf https://hdl.handle.net/10013/epic.16239.d001 Mark, F. C. orcid:0000-0002-5586-6704 , Bock, C. orcid:0000-0003-0052-3090 and Pörtner, H. O. orcid:0000-0001-6535-6575 (2002) Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS , American journal of physiology-regulatory integrative and comparative physiology, 283(5), R1254- R1262 . doi:10.1152/ajpregu.00167.2002. <https://doi.org/10.1152/ajpregu.00167.2002.> , hdl:10013/epic.16239 EPIC3American journal of physiology-regulatory integrative and comparative physiology, 283(5), R1254- R1262 Article isiRev 2002 ftawi https://doi.org/10.1152/ajpregu.00167.2002 2023-08-22T19:45:37Z The hypothesis of an oxygen limited thermal tolerance was tested in the Antarctic teleost Pachycara brachycephalum. Using flow-through respirometry, in vivo 31P-NMR spectroscopy and MRI, we studied energy metabolism, intracellular pH (pHi), blood-flow and oxygenation between 0 and 13°C under normoxia (PO2: 20,3 to 21,3kPa) and hyperoxia (PO2: 45kPa). Hyperoxia reduced the metabolic increment and the rise in arterial blood-flow observed under normoxia. The normoxic increase of blood-flow levelled off beyond 7°C, indicating a cardiovascular capacity limitation. Ventilatory effort displayed an exponential rise in both groups. In the liver, blood oxygenation increased, whereas in white muscle it remained unaltered (normoxia) or declined (hyperoxia). In both groups, the slope of pHi changes followed the alpha-stat pattern below 6°C, whereas it decreased above. In conclusion, aerobic scope declines around 6°C under normoxia, marking the pejus temperature Tp. By reducing circulatory costs, hyperoxia improves aerobic scope but is unable to shift the breakpoint in pH regulation or lethal limits. Hyperoxia appears beneficial at sublethal temperatures, but no longer beyond when cellular or molecular functions become disturbed. Article in Journal/Newspaper Antarc* Antarctic Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) Antarctic The Antarctic American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 283 5 R1254 R1262 |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
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The hypothesis of an oxygen limited thermal tolerance was tested in the Antarctic teleost Pachycara brachycephalum. Using flow-through respirometry, in vivo 31P-NMR spectroscopy and MRI, we studied energy metabolism, intracellular pH (pHi), blood-flow and oxygenation between 0 and 13°C under normoxia (PO2: 20,3 to 21,3kPa) and hyperoxia (PO2: 45kPa). Hyperoxia reduced the metabolic increment and the rise in arterial blood-flow observed under normoxia. The normoxic increase of blood-flow levelled off beyond 7°C, indicating a cardiovascular capacity limitation. Ventilatory effort displayed an exponential rise in both groups. In the liver, blood oxygenation increased, whereas in white muscle it remained unaltered (normoxia) or declined (hyperoxia). In both groups, the slope of pHi changes followed the alpha-stat pattern below 6°C, whereas it decreased above. In conclusion, aerobic scope declines around 6°C under normoxia, marking the pejus temperature Tp. By reducing circulatory costs, hyperoxia improves aerobic scope but is unable to shift the breakpoint in pH regulation or lethal limits. Hyperoxia appears beneficial at sublethal temperatures, but no longer beyond when cellular or molecular functions become disturbed. |
format |
Article in Journal/Newspaper |
author |
Mark, Felix Christopher Bock, Christian Pörtner, Hans-Otto |
spellingShingle |
Mark, Felix Christopher Bock, Christian Pörtner, Hans-Otto Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
author_facet |
Mark, Felix Christopher Bock, Christian Pörtner, Hans-Otto |
author_sort |
Mark, Felix Christopher |
title |
Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
title_short |
Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
title_full |
Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
title_fullStr |
Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
title_full_unstemmed |
Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS |
title_sort |
oxygen limited thermal tolerance in antarctic fish investigated by mri and 31p-mrs |
publishDate |
2002 |
url |
https://epic.awi.de/id/eprint/5676/ https://epic.awi.de/id/eprint/5676/1/Mar2002c.pdf https://doi.org/10.1152/ajpregu.00167.2002 https://hdl.handle.net/10013/epic.16239 https://hdl.handle.net/10013/epic.16239.d001 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
EPIC3American journal of physiology-regulatory integrative and comparative physiology, 283(5), R1254- R1262 |
op_relation |
https://epic.awi.de/id/eprint/5676/1/Mar2002c.pdf https://hdl.handle.net/10013/epic.16239.d001 Mark, F. C. orcid:0000-0002-5586-6704 , Bock, C. orcid:0000-0003-0052-3090 and Pörtner, H. O. orcid:0000-0001-6535-6575 (2002) Oxygen limited thermal tolerance in Antarctic fish investigated by MRI and 31P-MRS , American journal of physiology-regulatory integrative and comparative physiology, 283(5), R1254- R1262 . doi:10.1152/ajpregu.00167.2002. <https://doi.org/10.1152/ajpregu.00167.2002.> , hdl:10013/epic.16239 |
op_doi |
https://doi.org/10.1152/ajpregu.00167.2002 |
container_title |
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology |
container_volume |
283 |
container_issue |
5 |
container_start_page |
R1254 |
op_container_end_page |
R1262 |
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1776197144681644032 |