The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes
Antarctic icefishes of the family Channichthyidae are the only vertebrate animals that as adults do not express the circulating oxygen-binding protein hemoglobin (Hb). Six of the 16 family members also lack the intracellular oxygen-binding protein myoglobin (Mb) in the ventricle of their hearts and...
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fthighwire:oai:open-archive.highwire.org:icbiol:50/6/993 2023-05-15T14:02:57+02:00 The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes OBrien, Kristin M. Mueller, Irina A. 2010-12-01 00:00:00.0 text/html http://icb.oxfordjournals.org/cgi/content/short/50/6/993 https://doi.org/10.1093/icb/icq038 en eng Oxford University Press http://icb.oxfordjournals.org/cgi/content/short/50/6/993 http://dx.doi.org/10.1093/icb/icq038 Copyright (C) 2010, The Society for Integrative and Comparative Biology Advances in Antarctic Marine Biology TEXT 2010 fthighwire https://doi.org/10.1093/icb/icq038 2010-11-20T21:17:19Z Antarctic icefishes of the family Channichthyidae are the only vertebrate animals that as adults do not express the circulating oxygen-binding protein hemoglobin (Hb). Six of the 16 family members also lack the intracellular oxygen-binding protein myoglobin (Mb) in the ventricle of their hearts and all lack Mb in oxidative skeletal muscle. The loss of Hb has led to substantial remodeling in the cardiovascular system of icefishes to facilitate adequate oxygenation of tissues. One of the more curious adaptations to the loss of Hb and Mb is an increase in mitochondrial density in cardiac myocytes and oxidative skeletal muscle fibers. The proliferation of mitochondria in the aerobic musculature of icefishes does not arise through a canonical pathway of mitochondrial biogenesis. Rather, the biosynthesis of mitochondrial phospholipids is up-regulated independently of the synthesis of proteins and mitochondrial DNA, and newly-synthesized phospholipids are targeted primarily to the outer-mitochondrial membrane. Consequently, icefish mitochondria have a higher lipid-to-protein ratio compared to those from red-blooded species. Elevated levels of nitric oxide in the blood plasma of icefishes, compared to red-blooded notothenioids, may mediate alterations in mitochondrial density and architecture. Modifications in mitochondrial structure minimally impact state III respiration rates but may significantly enhance intracellular diffusion of oxygen. The rate of oxygen diffusion is greater within the hydrocarbon core of membrane lipids compared to the aqueous cytosol and impeded only by proteins within the lipid bilayer. Thus, the proliferation of icefish’s mitochondrial membranes provides an optimal conduit for the intracellular diffusion of oxygen and compensates for the loss of Hb and Mb. Currently little is known about how mitochondrial phospholipid synthesis is regulated and integrated into mitochondrial biogenesis. The unique architecture of the oxidative muscle cells of icefishes highlights the need for further studies in ... Text Antarc* Antarctic Icefish HighWire Press (Stanford University) Antarctic Integrative and Comparative Biology 50 6 993 1008 |
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Open Polar |
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HighWire Press (Stanford University) |
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fthighwire |
language |
English |
topic |
Advances in Antarctic Marine Biology |
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Advances in Antarctic Marine Biology OBrien, Kristin M. Mueller, Irina A. The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
topic_facet |
Advances in Antarctic Marine Biology |
description |
Antarctic icefishes of the family Channichthyidae are the only vertebrate animals that as adults do not express the circulating oxygen-binding protein hemoglobin (Hb). Six of the 16 family members also lack the intracellular oxygen-binding protein myoglobin (Mb) in the ventricle of their hearts and all lack Mb in oxidative skeletal muscle. The loss of Hb has led to substantial remodeling in the cardiovascular system of icefishes to facilitate adequate oxygenation of tissues. One of the more curious adaptations to the loss of Hb and Mb is an increase in mitochondrial density in cardiac myocytes and oxidative skeletal muscle fibers. The proliferation of mitochondria in the aerobic musculature of icefishes does not arise through a canonical pathway of mitochondrial biogenesis. Rather, the biosynthesis of mitochondrial phospholipids is up-regulated independently of the synthesis of proteins and mitochondrial DNA, and newly-synthesized phospholipids are targeted primarily to the outer-mitochondrial membrane. Consequently, icefish mitochondria have a higher lipid-to-protein ratio compared to those from red-blooded species. Elevated levels of nitric oxide in the blood plasma of icefishes, compared to red-blooded notothenioids, may mediate alterations in mitochondrial density and architecture. Modifications in mitochondrial structure minimally impact state III respiration rates but may significantly enhance intracellular diffusion of oxygen. The rate of oxygen diffusion is greater within the hydrocarbon core of membrane lipids compared to the aqueous cytosol and impeded only by proteins within the lipid bilayer. Thus, the proliferation of icefish’s mitochondrial membranes provides an optimal conduit for the intracellular diffusion of oxygen and compensates for the loss of Hb and Mb. Currently little is known about how mitochondrial phospholipid synthesis is regulated and integrated into mitochondrial biogenesis. The unique architecture of the oxidative muscle cells of icefishes highlights the need for further studies in ... |
format |
Text |
author |
OBrien, Kristin M. Mueller, Irina A. |
author_facet |
OBrien, Kristin M. Mueller, Irina A. |
author_sort |
OBrien, Kristin M. |
title |
The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
title_short |
The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
title_full |
The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
title_fullStr |
The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
title_full_unstemmed |
The Unique Mitochondrial Form and Function of Antarctic Channichthyid Icefishes |
title_sort |
unique mitochondrial form and function of antarctic channichthyid icefishes |
publisher |
Oxford University Press |
publishDate |
2010 |
url |
http://icb.oxfordjournals.org/cgi/content/short/50/6/993 https://doi.org/10.1093/icb/icq038 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Icefish |
genre_facet |
Antarc* Antarctic Icefish |
op_relation |
http://icb.oxfordjournals.org/cgi/content/short/50/6/993 http://dx.doi.org/10.1093/icb/icq038 |
op_rights |
Copyright (C) 2010, The Society for Integrative and Comparative Biology |
op_doi |
https://doi.org/10.1093/icb/icq038 |
container_title |
Integrative and Comparative Biology |
container_volume |
50 |
container_issue |
6 |
container_start_page |
993 |
op_container_end_page |
1008 |
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1766273409879113728 |