Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin
Abstract: Antarctic notothenioids are noted for extreme stenothermy, yet underpinnings of their thermal limits are not fully understood. We hypothesized that properties of ventricular membranes could explain previously observed differences among notothenioids in temperature onset of cardiac arrhythm...
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IEDA: US Antarctic Program Data Center
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dataone:http://get.iedadata.org/metadata/iso/601414 2024-06-03T18:46:23+00:00 Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin Crockett, Elizabeth Evans, Elizabeth Farnoud, Amir O'Brien, Kristin 2020-12-24T00:00:00Z http://get.iedadata.org/metadata/iso/601414 unknown IEDA: US Antarctic Program Data Center Cryosphere Antarctica Antarctic Peninsula US Antarctic Program Data Center (USAP-DC) Dataset 2020 dataone:urn:node:IEDA_USAP 2024-06-03T18:17:00Z Abstract: Antarctic notothenioids are noted for extreme stenothermy, yet underpinnings of their thermal limits are not fully understood. We hypothesized that properties of ventricular membranes could explain previously observed differences among notothenioids in temperature onset of cardiac arrhythmias and persistent asystole. Microsomes were prepared using ventricles from six species of notothenioids, including four species from the hemoglobin-less (Hb-) family Channichthyidae (icefishes), which also differentially express cardiac myoglobin (Mb), and two species from the (Hb+) Nototheniidae. We determined membrane fluidity and structural integrity by quantifying fluorescence depolarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and leakage of 5(6)-carboxyfluorescein, respectively, over a temperature range from ambient (0 °C) to 20 °C. Compositions of membrane phospholipids and cholesterol contents were also quantified. Membranes from all four species of icefishes exhibited greater fluidity than membranes from the red-blooded species N. coriiceps. Thermal sensitivity of fluidity did not vary among species. The greatest thermal sensitivity to leakage occurred between 0 and 5 °C for all species, while membranes from the icefish, Chaenocephalus aceratus (Hb-/Mb-) displayed leakage that was nearly 1.5-fold greater than leakage in N. coriiceps (Hb+/Mb+). Contents of phosphatidylethanolamine (PE) were approximately 1.5-fold greater in icefishes than in red-blooded fishes, and phospholipids had a higher degree of unsaturation in icefishes than in Hb + notothenioids. Cholesterol contents were lowest in Champsocephalus gunnari (Hb-/Mb-) and highest in the two Hb+/Mb + species, G. gibberifrons and N. coriiceps. Our results reveal marked differences in membrane properties and indicate a breach in membrane fluidity and structural integrity at a lower temperature in icefishes than in red-blooded notothenioids. Dataset Antarc* Antarctic Antarctic Peninsula Antarctica Icefish IEDA: US Antarctic Program Data Center (via DataONE) Antarctic Antarctic Peninsula |
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Open Polar |
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IEDA: US Antarctic Program Data Center (via DataONE) |
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dataone:urn:node:IEDA_USAP |
language |
unknown |
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Cryosphere Antarctica Antarctic Peninsula US Antarctic Program Data Center (USAP-DC) |
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Cryosphere Antarctica Antarctic Peninsula US Antarctic Program Data Center (USAP-DC) Crockett, Elizabeth Evans, Elizabeth Farnoud, Amir O'Brien, Kristin Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
topic_facet |
Cryosphere Antarctica Antarctic Peninsula US Antarctic Program Data Center (USAP-DC) |
description |
Abstract: Antarctic notothenioids are noted for extreme stenothermy, yet underpinnings of their thermal limits are not fully understood. We hypothesized that properties of ventricular membranes could explain previously observed differences among notothenioids in temperature onset of cardiac arrhythmias and persistent asystole. Microsomes were prepared using ventricles from six species of notothenioids, including four species from the hemoglobin-less (Hb-) family Channichthyidae (icefishes), which also differentially express cardiac myoglobin (Mb), and two species from the (Hb+) Nototheniidae. We determined membrane fluidity and structural integrity by quantifying fluorescence depolarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and leakage of 5(6)-carboxyfluorescein, respectively, over a temperature range from ambient (0 °C) to 20 °C. Compositions of membrane phospholipids and cholesterol contents were also quantified. Membranes from all four species of icefishes exhibited greater fluidity than membranes from the red-blooded species N. coriiceps. Thermal sensitivity of fluidity did not vary among species. The greatest thermal sensitivity to leakage occurred between 0 and 5 °C for all species, while membranes from the icefish, Chaenocephalus aceratus (Hb-/Mb-) displayed leakage that was nearly 1.5-fold greater than leakage in N. coriiceps (Hb+/Mb+). Contents of phosphatidylethanolamine (PE) were approximately 1.5-fold greater in icefishes than in red-blooded fishes, and phospholipids had a higher degree of unsaturation in icefishes than in Hb + notothenioids. Cholesterol contents were lowest in Champsocephalus gunnari (Hb-/Mb-) and highest in the two Hb+/Mb + species, G. gibberifrons and N. coriiceps. Our results reveal marked differences in membrane properties and indicate a breach in membrane fluidity and structural integrity at a lower temperature in icefishes than in red-blooded notothenioids. |
format |
Dataset |
author |
Crockett, Elizabeth Evans, Elizabeth Farnoud, Amir O'Brien, Kristin |
author_facet |
Crockett, Elizabeth Evans, Elizabeth Farnoud, Amir O'Brien, Kristin |
author_sort |
Crockett, Elizabeth |
title |
Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
title_short |
Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
title_full |
Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
title_fullStr |
Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
title_full_unstemmed |
Thermal sensitivity of membrane fluidity and integrity in hearts of Antarctic fishes that vary in expression of hemoglobin and myoglobin |
title_sort |
thermal sensitivity of membrane fluidity and integrity in hearts of antarctic fishes that vary in expression of hemoglobin and myoglobin |
publisher |
IEDA: US Antarctic Program Data Center |
publishDate |
2020 |
url |
http://get.iedadata.org/metadata/iso/601414 |
geographic |
Antarctic Antarctic Peninsula |
geographic_facet |
Antarctic Antarctic Peninsula |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Icefish |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Icefish |
_version_ |
1800871426650013696 |