Cargando…

Mitochondria and the Frozen Frog

The wood frog, Rana sylvatica, is the best-studied of a small group of amphibian species that survive whole body freezing during the winter months. These frogs endure the freezing of 65–70% of their total body water in extracellular ice masses. They have implemented multiple adaptations that manage...

Descripción completa

Detalles Bibliográficos
Autores principales: Storey, Janet M., Wu, Shaobo, Storey, Kenneth B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067143/
https://www.ncbi.nlm.nih.gov/pubmed/33915853
http://dx.doi.org/10.3390/antiox10040543
_version_ 1783682732575948800
author Storey, Janet M.
Wu, Shaobo
Storey, Kenneth B.
author_facet Storey, Janet M.
Wu, Shaobo
Storey, Kenneth B.
author_sort Storey, Janet M.
collection PubMed
description The wood frog, Rana sylvatica, is the best-studied of a small group of amphibian species that survive whole body freezing during the winter months. These frogs endure the freezing of 65–70% of their total body water in extracellular ice masses. They have implemented multiple adaptations that manage ice formation, deal with freeze-induced ischemia/reperfusion stress, limit cell volume reduction with the production of small molecule cryoprotectants (glucose, urea) and adjust a wide variety of metabolic pathways for prolonged life in a frozen state. All organs, tissues, cells and intracellular organelles are affected by freeze/thaw and its consequences. This article explores mitochondria in the frozen frog with a focus on both the consequences of freezing (e.g., anoxia/ischemia, cell volume reduction) and mitigating defenses (e.g., antioxidants, chaperone proteins, upregulation of mitochondria-encoded genes, enzyme regulation, etc.) in order to identify adaptive strategies that defend and adapt mitochondria in animals that can be frozen for six months or more every year. A particular focus is placed on freeze-responsive genes in wood frogs that are encoded on the mitochondrial genome including ATP6/8, ND4 and 16S RNA. These were strongly up-regulated during whole body freezing (24 h at −2.5 °C) in the liver and brain but showed opposing responses to two component stresses: strong upregulation in response to anoxia but no response to dehydration stress. This indicates that freeze-responsive upregulation of mitochondria-encoded genes is triggered by declining oxygen and likely has an adaptive function in supporting cellular energetics under indeterminate lengths of whole body freezing.
format Online
Article
Text
id pubmed-8067143
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-80671432021-04-25 Mitochondria and the Frozen Frog Storey, Janet M. Wu, Shaobo Storey, Kenneth B. Antioxidants (Basel) Review The wood frog, Rana sylvatica, is the best-studied of a small group of amphibian species that survive whole body freezing during the winter months. These frogs endure the freezing of 65–70% of their total body water in extracellular ice masses. They have implemented multiple adaptations that manage ice formation, deal with freeze-induced ischemia/reperfusion stress, limit cell volume reduction with the production of small molecule cryoprotectants (glucose, urea) and adjust a wide variety of metabolic pathways for prolonged life in a frozen state. All organs, tissues, cells and intracellular organelles are affected by freeze/thaw and its consequences. This article explores mitochondria in the frozen frog with a focus on both the consequences of freezing (e.g., anoxia/ischemia, cell volume reduction) and mitigating defenses (e.g., antioxidants, chaperone proteins, upregulation of mitochondria-encoded genes, enzyme regulation, etc.) in order to identify adaptive strategies that defend and adapt mitochondria in animals that can be frozen for six months or more every year. A particular focus is placed on freeze-responsive genes in wood frogs that are encoded on the mitochondrial genome including ATP6/8, ND4 and 16S RNA. These were strongly up-regulated during whole body freezing (24 h at −2.5 °C) in the liver and brain but showed opposing responses to two component stresses: strong upregulation in response to anoxia but no response to dehydration stress. This indicates that freeze-responsive upregulation of mitochondria-encoded genes is triggered by declining oxygen and likely has an adaptive function in supporting cellular energetics under indeterminate lengths of whole body freezing. MDPI 2021-04-01 /pmc/articles/PMC8067143/ /pubmed/33915853 http://dx.doi.org/10.3390/antiox10040543 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Review
Storey, Janet M.
Wu, Shaobo
Storey, Kenneth B.
Mitochondria and the Frozen Frog
title Mitochondria and the Frozen Frog
title_full Mitochondria and the Frozen Frog
title_fullStr Mitochondria and the Frozen Frog
title_full_unstemmed Mitochondria and the Frozen Frog
title_short Mitochondria and the Frozen Frog
title_sort mitochondria and the frozen frog
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067143/
https://www.ncbi.nlm.nih.gov/pubmed/33915853
http://dx.doi.org/10.3390/antiox10040543
work_keys_str_mv AT storeyjanetm mitochondriaandthefrozenfrog
AT wushaobo mitochondriaandthefrozenfrog
AT storeykennethb mitochondriaandthefrozenfrog