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Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver

Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body’s iron, w...

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Autores principales: Corliss, Bruce A., Delalio, Leon J., Stevenson Keller, T. C., Keller, Alexander S., Keller, Douglas A., Corliss, Bruce H., Beers, Jody M., Peirce, Shayn M., Isakson, Brant E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861181/
https://www.ncbi.nlm.nih.gov/pubmed/31780954
http://dx.doi.org/10.3389/fphys.2019.01389
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author Corliss, Bruce A.
Delalio, Leon J.
Stevenson Keller, T. C.
Keller, Alexander S.
Keller, Douglas A.
Corliss, Bruce H.
Beers, Jody M.
Peirce, Shayn M.
Isakson, Brant E.
author_facet Corliss, Bruce A.
Delalio, Leon J.
Stevenson Keller, T. C.
Keller, Alexander S.
Keller, Douglas A.
Corliss, Bruce H.
Beers, Jody M.
Peirce, Shayn M.
Isakson, Brant E.
author_sort Corliss, Bruce A.
collection PubMed
description Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body’s iron, which is known to be a limiting nutrient in marine ecosystems. Since lower RBC levels also lead to reduced iron requirements, we hypothesize that low iron availability was an additional evolutionary driver of Antarctic fish speciation. Antarctic Icefish of the family Channichthyidae are known to have an extreme alteration of iron metabolism due to loss of RBCs and two iron-binding proteins, hemoglobin and myoglobin. Loss of hemoglobin is considered a maladaptive trait allowed by relaxation of predator selection since extreme adaptations are required to compensate for the loss of oxygen-carrying capacity. However, iron dependency minimization may have driven hemoglobin loss instead of a random evolutionary event. Given the variety of functions that hemoglobin serves in the endothelium, we suspected the protein corresponding to the 3’ truncated Hbα fragment (Hbα-3’f) that was not genetically excluded by icefish may still be expressed as a protein. Using whole mount confocal microscopy, we show that Hbα-3’f is expressed in the vascular endothelium of icefish retina, suggesting this Hbα fragment may still serve an important role in the endothelium. These observations support a novel hypothesis that iron minimization could have influenced icefish speciation with the loss of the iron-binding portion of Hbα in Hbα-3’f, as well as hemoglobin β and myoglobin.
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spelling pubmed-68611812019-11-28 Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver Corliss, Bruce A. Delalio, Leon J. Stevenson Keller, T. C. Keller, Alexander S. Keller, Douglas A. Corliss, Bruce H. Beers, Jody M. Peirce, Shayn M. Isakson, Brant E. Front Physiol Physiology Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body’s iron, which is known to be a limiting nutrient in marine ecosystems. Since lower RBC levels also lead to reduced iron requirements, we hypothesize that low iron availability was an additional evolutionary driver of Antarctic fish speciation. Antarctic Icefish of the family Channichthyidae are known to have an extreme alteration of iron metabolism due to loss of RBCs and two iron-binding proteins, hemoglobin and myoglobin. Loss of hemoglobin is considered a maladaptive trait allowed by relaxation of predator selection since extreme adaptations are required to compensate for the loss of oxygen-carrying capacity. However, iron dependency minimization may have driven hemoglobin loss instead of a random evolutionary event. Given the variety of functions that hemoglobin serves in the endothelium, we suspected the protein corresponding to the 3’ truncated Hbα fragment (Hbα-3’f) that was not genetically excluded by icefish may still be expressed as a protein. Using whole mount confocal microscopy, we show that Hbα-3’f is expressed in the vascular endothelium of icefish retina, suggesting this Hbα fragment may still serve an important role in the endothelium. These observations support a novel hypothesis that iron minimization could have influenced icefish speciation with the loss of the iron-binding portion of Hbα in Hbα-3’f, as well as hemoglobin β and myoglobin. Frontiers Media S.A. 2019-11-12 /pmc/articles/PMC6861181/ /pubmed/31780954 http://dx.doi.org/10.3389/fphys.2019.01389 Text en Copyright © 2019 Corliss, Delalio, Stevenson Keller, Keller, Keller, Corliss, Beers, Peirce and Isakson. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physiology
Corliss, Bruce A.
Delalio, Leon J.
Stevenson Keller, T. C.
Keller, Alexander S.
Keller, Douglas A.
Corliss, Bruce H.
Beers, Jody M.
Peirce, Shayn M.
Isakson, Brant E.
Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title_full Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title_fullStr Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title_full_unstemmed Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title_short Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver
title_sort vascular expression of hemoglobin alpha in antarctic icefish supports iron limitation as novel evolutionary driver
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6861181/
https://www.ncbi.nlm.nih.gov/pubmed/31780954
http://dx.doi.org/10.3389/fphys.2019.01389
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