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Contreras J, Gomà J, Velalcázar D, Montori A. Thermal Tolerance and Preferred Temperature in the Critical Endangered Montseny Brook Newt ( Calotriton arnoldi). Animals (Basel) 2024; 14:1963. [PMID: 38998074 PMCID: PMC11240504 DOI: 10.3390/ani14131963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 06/24/2024] [Accepted: 06/29/2024] [Indexed: 07/14/2024] Open
Abstract
Climate change, driven by increased human greenhouse gas emissions since the beginning of the industrial revolution up to the present day, is considered one of the major threats to biodiversity in the twenty-first century. One of the most affected groups is the ectotherms due to their direct dependence on environmental temperatures. In recent years, several studies have analysed the effects of temperature and thermal tolerance on several species of ectotherms. However, there are species whose thermal tolerances are still unknown. Such is the case of the critically endangered species, the Montseny Brook Newt (Calotriton arnoldi), endemic to the Montseny massif in Spain and whose thermal biology is unknown. Its critical situation makes it essential to know its tolerance to cooling, warming and thermopreferendum in water environments where the newt lives. Three experimental procedures were conducted from the western and eastern subspecies of C. arnoldi, considering four classes separately (males, females, juveniles and larvae). The results obtained showed that the CTmax of the species exceeded 31 °C, with a significant difference between the two subspecies. We found that the species tolerates low temperatures (<1 °C) well because the genera Calotriton is adapted to live in cold waters with temperatures below 15 °C. Although the thermopreference of the species was expected to trend to cold temperatures, some individuals chose relatively high temperatures, obtaining a range of 11.7 °C to 21.6 °C. The results presented in this study are an advance in the knowledge of the thermal physiology of this species and support the importance of the temperature of the torrent on its survival. Knowing their thermal limits and their preferred temperature range will help to propose management measures that promote the conservation of streams and riparian forest cover to mitigate temperature increases due to climate change.
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Affiliation(s)
- Jenifer Contreras
- Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Avenida 12 de Octubre 1076, Quito 170143, Ecuador;
| | - Joan Gomà
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, University of Barcelona, 08028 Barcelona, Spain;
- Freshwater Ecology, Hydrology, and Management Laboratory (FEHM-Lab), University of Barcelona, 08028 Barcelona, Spain
| | - David Velalcázar
- Facultad de Ciencias de la Salud, Pontificia Universidad Católica del Ecuador, Av. Manuelita Sáenz, Ambato 180207, Ecuador;
| | - Albert Montori
- CREAC, Centre de Recerca i Educació Ambiental de Calafell, Secció Herpetologia, Aj, Calafell, 43882 Tarragona, Spain
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Park JK, DO Y. The difference and variation of gut bacterial community and host physiology can support adaptation during and after overwintering in frog population. Integr Zool 2024; 19:631-645. [PMID: 38185804 DOI: 10.1111/1749-4877.12798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The hibernation of amphibians can offer a unique window into overwintering adaptation processes and host-gut microbiota interactions through changes in metabolic availability and homeostasis. We attempted to identify differences in the physiology and gut microbiome during and after hibernation in Japanese wrinkled frogs (Glandirana rugosa), an aquatic overwintering amphibian. After hibernation, the high alpha and beta diversity of the gut bacterial community appears to reflect the more diverse and complex environmental conditions. During winter, Proteobacteria dominated the majority of the gut bacterial community, likely due to high oxygen saturation. After hibernation, Firmicutes and Bacteroidetes increased, which are supportive of host metabolism by gut microbiota. Corticosterone also showed high values and variances after hibernation, presumably allowing the population to remain adaptable across a broad range of environmental gradients. Innate immunity was high after hibernation but exhibited low variation among populations, which supports the idea of a prioritized investment in immunity after hibernation. Blood biochemistry suggests that aquatic overwintering frogs have a mechanism to adapt through overhydration and regulate homeostasis through water excretion associated with the kidney and urine after hibernation. Frog populations exhibit variations and adaptability in gut microbiota and physiology during and after hibernation: Through this, they may demonstrate an adaptive response that regulates metabolic availability in preparation for unpredictable environmental changes. We also propose that the maintenance of Proteobacteria during hibernation can support the colonization of Firmicutes and Bacteroidetes after hibernation, underscoring the need to study the complex effects of gut microbiota across multiple life stages.
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Affiliation(s)
- Jun-Kyu Park
- Department of Biological Sciences, Kongju National University, Gongju, Chungcheongnam-do, South Korea
| | - Yuno DO
- Department of Biological Sciences, Kongju National University, Gongju, Chungcheongnam-do, South Korea
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Ning Z, Chen Y, Wang Z, Zhou H, Sun M, Yao T, Mu W. Transcriptome, histological, and physiological responses of Amur sleeper (Perccottus glenii) during cold stress, freezing, and recovery. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 49:101192. [PMID: 38278046 DOI: 10.1016/j.cbd.2024.101192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 01/28/2024]
Abstract
Freeze tolerance is a survival strategy employed by some ectotherms living in extremely cold environments. Some fish in extremely cold areas can recover from their frozen state, but they also have to endure cold stress. Amur sleeper (Perccottus glenii) can recover from a completely frozen state. To explore the response of freeze-resistant fish to low temperatures, we analyzed histological alterations, and antioxidant and carbohydrate-lipid metabolizing enzymes of P. glenii under low temperatures. So far, sensory genes regulating P. glenii during cold stress, freezing, and recovery have not been identified. Ultrastructure results indicated that glycogen content and mitochondrial ridge decreased during cold stress and freezing, whereas the number of endoplasmic reticulum increased during recovery. Plasma glucose and glycerol levels of the three treatment groups significantly increased. Lactate dehydrogenase and pyruvate kinase levels significantly increased during cold stress and freezing, and hexokinase levels significantly increased during cold stress. In total, 30,560 unigenes were found (average length 1724 bp, N50 2843 bp). In addition, 7370 differentially expressed genes (DEGs; including 2938 upregulated genes and 4432 downregulated genes) were identified. KEGG analysis revealed that the DEGs were enriched in carbohydrate and lipid metabolism, lipid synthesis, immune system, and anti-apoptosis. Genes involved in glycolysis and phospholipid metabolism were significantly upregulated during cold stress; genes related to circadian rhythm, oxidative phosphorylation, and lipid synthesis were significantly upregulated during freezing; and genes involved in the immune system and anti-apoptosis were significantly upregulated during recovery. Our results attempt to offer new insights into the physiological mechanisms of complex adaptation in P. glenii and provide useful information for future studies on the mechanism underlying freezing/recovery in animals.
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Affiliation(s)
- Zhaoyang Ning
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Yingqiao Chen
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Zijian Wang
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Haishui Zhou
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Mingyang Sun
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Tiehui Yao
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China
| | - Weijie Mu
- Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin 150025, China.
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Wohlgemuth RP, Haro D, Liwanag HEM. Osmotic and metabolic responses to cold acclimation and acute cold challenge in a freeze avoidant lizard, Podarcis siculus. Comp Biochem Physiol A Mol Integr Physiol 2023:111471. [PMID: 37390889 DOI: 10.1016/j.cbpa.2023.111471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/19/2023] [Accepted: 06/26/2023] [Indexed: 07/02/2023]
Abstract
Ectotherms survive exposure to subzero temperatures through freeze tolerance or freeze avoidance. Among vertebrate ectotherms, glucose is commonly used as a cryoprotectant in freeze tolerant strategies and as an osmolyte in freeze avoidant strategies, while also functioning as a metabolic substrate. Whereas some lizard species are capable of both freeze tolerance and freeze avoidance, Podarcis siculus is limited to freeze avoidance through supercooling. We hypothesized that, even in a freeze-avoidant species such as P. siculus, plasma glucose would accumulate with cold acclimation and would increase in response to acute exposure to subzero temperatures. To investigate this, we tested whether plasma glucose concentration and osmolality would increase in response to a subzero cold challenge before and after cold acclimation. In addition, we examined the relationship between metabolic rate, cold acclimation, and glucose by measuring metabolic rate during the cold challenge trials. We found that plasma glucose increased during the cold challenge trials, and that the increase was more pronounced after cold acclimation. However, baseline plasma glucose decreased throughout cold acclimation. Interestingly, total plasma osmolality did not change, and the increase in glucose only slightly altered freezing point depression. Metabolic rate during the cold challenge decreased after cold acclimation, and changes in respiratory exchange ratio suggest an increased relative use of carbohydrates. Overall, our findings demonstrate an important role for glucose in the response of P. siculus to an acute cold challenge, thus adding evidence for glucose as an important molecule for overwintering ectotherms that use freeze avoidant strategies.
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Affiliation(s)
- Ross Paul Wohlgemuth
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA; Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, CA 95616, USA.
| | - Daniel Haro
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
| | - Heather E M Liwanag
- Department of Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407, USA
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Varma A, Storey KB. Freeze-induced suppression of pyruvate kinase in liver of the wood frog (Rana sylvatica). Adv Biol Regul 2023; 88:100944. [PMID: 36542984 DOI: 10.1016/j.jbior.2022.100944] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/22/2022] [Accepted: 12/14/2022] [Indexed: 05/22/2023]
Abstract
The wood frog (Rana sylvatica) undergoes physiological and metabolic changes to withstand subzero temperatures and whole body freezing during the winter months. Along with metabolic rate depression, high concentrations of glucose are produced as a cryoprotectant by liver and distributed to all other tissues. Pyruvate kinase (PK; EC:2.7.1.40), the final enzyme of glycolysis, plays an important role in the modulation of glucose metabolism and, therefore, overall metabolic regulation. The present study investigated the functional and kinetic properties of purified PK from liver of control (5 °C acclimated) and frozen (-2.5 °C for 24 h) wood frogs. Liver PK was purified to homogeneity by a two-step chromatographic process, followed by analysis of enzyme properties. A significant decrease in the affinity of PK for its substrates, phosphoenolpyruvate (PEP) and adenosine diphosphate (ADP) at 22 °C and 5 °C was noted in liver from frozen frogs, as compared with controls. Immunoblotting also revealed freeze-responsive changes in posttranslational modifications with a significant increase in serine and threonine phosphorylation by 1.46-fold and 1.73- fold for PK from frozen frogs as compared with controls. Furthermore, a test of thermal stability showed that PK from liver of frozen wood frogs showed greater stability as compared with PK from control animals. Taken together, these results suggest that PK is negatively regulated, and glycolysis is suppressed, during freezing. This response acts as an important survival strategy for maintaining continuously elevated levels of cryoprotectant in frogs while they remain in a hypometabolic frozen state.
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Affiliation(s)
- Anchal Varma
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel by Drive, Ottawa, Ontario, K1S 5B6, Canada
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel by Drive, Ottawa, Ontario, K1S 5B6, Canada.
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Cryoprotection in Human Mesenchymal Stromal/Stem Cells: Synergistic Impact of Urea and Glucose. J Pharm Sci 2023; 112:1681-1686. [PMID: 36754231 DOI: 10.1016/j.xphs.2023.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 02/10/2023]
Abstract
Standard freezing protocols of clinically relevant cell lines commonly employ agents such as fetal bovine serum and dimethyl sulfoxide, which are a potential concern from both a regulatory and a patient safety perspective. The aim of this work was to develop formulations with safe and well tolerated excipients for the (cryo-) preservation of cell therapy products. We evaluated the cryoprotective capabilities of urea and glucose through measurements of cell metabolic activity. Freezing of clinically relevant human mesenchymal stromal/stem cells and human dermal fibroblasts at ≤ - 65°C at equimolar ratios of urea and glucose resulted in comparable viabilities to established dimethyl sulfoxide. Pre-incubation of human mesenchymal stromal/stem cells in trehalose and addition of mannitol and sucrose to the formulation further enhanced cell viability after freeze-thaw stress. Other cell types assessed (A549 and SK-N-AS) could not satisfactorily be preserved with urea and glucose, highlighting the need for tailored formulations to sustain acceptable cryopreservation.
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YOLDAS T, ERİŞMİŞ UC. Hayvanlarda Soğuğa Dayanıklılık: Çift Yaşarların Kriyobiyolojisi. COMMAGENE JOURNAL OF BIOLOGY 2022. [DOI: 10.31594/commagene.1176451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Organizmalar yaşamlarını devam ettirebilmek için abiyotik çevresel koşullara uyum sağlarlar. Özellikle ortam sıcaklığındaki değişimler; canlıların beslenme, üreme, gelişim ve morfolojileri üzerinde etkilidir. Sıra dışı sıcaklık değişimleri özellikle ektotermik hayvanlar için ölümcül olabilir. Karasal ektotermler. doğada donma noktasının altındaki sıcaklıklarda hayatta kalabilmek için davranışsal, fizyolojik ve biyokimyasal bazı özel stratejiler geliştirmişlerdir. Bazı türler göç ederek su ya da toprak altında kış uykusuna yatmak suretiyle dondurucu sıcaklıklardan kaçınırlar. Bazıları ise donma koşullarına maruz kalarak kışı geçirmek zorundadırlar. Genel olarak dondurucu soğuğa dayanıklılık donmadan kaçınma (süper soğuma) ve donma toleransı stratejilerine bağlıdır. Donmadan kaçınma durumunda vücut sıvılarının donma noktasının altındaki sıcaklıklarda sıvı formu korunurken donma toleransı stratejisini kullanan canlılarda ise vücutlarındaki toplam suyun %50’sinden fazlasının donması tolere edilebilir. Karasal hibernatör hayvanlardan bazı amfibi ve sürüngen gruplarında da tespit edilen donma toleransı stratejisi onların dondurucu kış koşullarında hayatta kalmalarını sağlamaktadır. Bu özel türler kriyoprotektif mekanizmaları ile donmanın ölümcül etkilerinden korunurlar. Donma süresince yaşamsal faaliyetleri tamamen duran bu hayvanlar çözündükten sonra kısa bir süre içerisinde de normal yaşama dönerler. Bu mucizevi mekanizmanın araştırılması yalnızca hayvanların karmaşık adaptasyonunu açıklamakla kalmaz, aynı zamanda doku ve hücre kriyoprezervasyon teknolojisine de kaynak sağlar. Bu derleme amfibilerin donma toleransı stratejilerine dair bilgiler sunarak henüz yeterince çalışılmamış bu konuda araştırma yapmak isteyenlere katkı sağlayacaktır.
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Affiliation(s)
- Taner YOLDAS
- DÜZCE ÜNİVERSİTESİ, BİLİMSEL VE TEKNOLOJİK ARAŞTIRMALAR UYGULAMA VE ARAŞTIRMA MERKEZİ
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Niu Y, Chen Q, Storey KB, Teng L, Li X, Xu T, Zhang H. Physiological ecology of winter hibernation by the high-altitude frog, Nanorana parkeri. Physiol Biochem Zool 2022; 95:201-211. [DOI: 10.1086/718764] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Van Meter RJ, Glinski DA, Purucker ST, Henderson WM. Induced Hepatic Glutathione and Metabolomic Alterations Following Mixed Pesticide and Fertilizer Exposures in Juvenile Leopard Frogs (Lithobates sphenocephala). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:122-133. [PMID: 34967044 PMCID: PMC8935487 DOI: 10.1002/etc.5245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
The increasing use of agrochemicals, alone and in combination, has been implicated as a potential causative factor in the decline of amphibians worldwide. Fertilizers and pesticides are frequently combined into single-use tank mixtures for agricultural applications to decrease costs while meeting the food demands of a growing human population. Limited data are available on the effects of increased nitrogen levels in nontarget species, such as amphibians, and therefore investigating alterations in the nitrogen cycle and its impacts on amphibians needs to be considered in best management practices going forward. The objective of the present study was to elucidate the impact of fertilizer (urea) and herbicide (atrazine and/or alachlor) tank mixtures on the hepatic metabolome of juvenile leopard frogs as well as to investigate alterations in oxidative stress by relating these changes to glutathione (GSH) levels. Herbicide exposure only moderately increased this parameter in amphibians, however, urea alone and in combination with either atrazine or alachlor statistically elevated GSH levels. Interestingly, urea also inhibited pesticide uptake: calculated bioconcentration factors were greatly decreased for atrazine and alachlor when urea was present in the exposure mixture. Metabolomic profiling identified fluxes in hepatic metabolites that are involved in GSH and carbohydrate metabolic processes as well as altered intermediates in the urea cycle. Ultimately, understanding the biological impacts of nitrogenous fertilizers alone and in combination with pesticide exposure will inform best management practices to conserve declining amphibian populations worldwide. Environ Toxicol Chem 2022;41:122-133. © 2021 SETAC.
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Affiliation(s)
| | | | - S Thomas Purucker
- Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, Durham, North Carolina, USA
| | - W Matthew Henderson
- Center for Measurement and Modeling, Office of Research and Development, US Environmental Protection Agency, Athens, Georgia, USA
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Dahl HA, Johansen A, Nilsson GE, Lefevre S. The Metabolomic Response of Crucian Carp ( Carassius carassius) to Anoxia and Reoxygenation Differs between Tissues and Hints at Uncharacterized Survival Strategies. Metabolites 2021; 11:435. [PMID: 34357329 PMCID: PMC8304758 DOI: 10.3390/metabo11070435] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/16/2021] [Accepted: 06/25/2021] [Indexed: 01/15/2023] Open
Abstract
The anoxia-tolerant crucian carp (Carassius carassius) has been studied in detail for numerous years, with particular focus on unravelling the underlying physiological mechanisms of anoxia tolerance. However, relatively little work has been focused on what occurs beyond anoxia, and often the focus is a single organ or tissue type. In this study, we quantified more than 100 metabolites by capillary electrophoresis-mass spectrometry (CE-MS) in brain, heart, liver, and blood plasma from four experimental groups, being normoxic (control) fish, anoxia-exposed fish, and two groups that had been exposed to anoxia followed by reoxygenation for either 3 h or 24 h. The heart, which maintains cardiac output during anoxia, unexpectedly, was slower to recover compared to the brain and liver, mainly due to a slower return to control concentrations of the energy-carrying compounds ATP, GTP, and phosphocreatine. Crucian carp accumulated amino acids in most tissues, and also surprisingly high levels of succinate in all tissues investigated during anoxia. Purine catabolism was enhanced, leading to accumulation of uric acid during anoxia and increasing urea formation that continued into 24 h of reoxygenation. These tissue-specific differences in accumulation and distribution of the metabolites may indicate an intricate system of transport between tissues, opening for new avenues of investigation of possible mechanisms aimed at reducing the generation of reactive oxygen species (ROS) and resultant tissue damage during reoxygenation.
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Affiliation(s)
| | | | | | - Sjannie Lefevre
- Section for Physiology and Cell Biology, Department of Biosciences, University of Oslo, 0371 Oslo, Norway; (H.-A.D.); (A.J.); (G.E.N.)
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Mitochondria and the Frozen Frog. Antioxidants (Basel) 2021; 10:antiox10040543. [PMID: 33915853 PMCID: PMC8067143 DOI: 10.3390/antiox10040543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/25/2021] [Accepted: 03/29/2021] [Indexed: 01/06/2023] Open
Abstract
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.
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Freeze tolerance and the underlying metabolite responses in the Xizang plateau frog, Nanorana parkeri. J Comp Physiol B 2020; 191:173-184. [PMID: 33025179 DOI: 10.1007/s00360-020-01314-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/05/2020] [Accepted: 09/16/2020] [Indexed: 10/23/2022]
Abstract
The frog Nanorana parkeri (Dicroglossidae) is endemic to the Tibetan Plateau, and overwinters shallow pond within damp caves for up to 6 months. Herein, we investigate the freeze tolerance of this species and profile changes in liver and skeletal muscle metabolite levels using an untargeted LC-MS-based metabolomic approach to investigate molecular mechanisms that may contribute to freezing survival. We found that three of seven specimens of N. parkeri could survive after being frozen for 12 h at - 2.0 °C with 39.91% ± 5.4% (n = 7) of total body water converted to ice. Freezing exposure induced partial dehydration of the muscle, which contributed to decreasing the amount of freezable water within the muscle and could be protective for the myocytes themselves. A comparative metabolomic analysis showed that freezing elicited significant responses, and a total of 33 and 36 differentially expressed metabolites were identified in the liver and muscle, respectively. These metabolites mainly participate in alanine, aspartic acid and glutamic acid metabolism, arginine and proline metabolism, and D-glutamine and D-glutamate metabolism. After freezing exposure, the contents of ornithine, melezitose, and maltotriose rose significantly; these may act as cryoprotectants. Additionally, the content of 8-hydroxy-2-deoxyguanine, 7-Ketocholesterol and hypoxanthine showed a marked increase, suggesting that freezing induced oxidative stress in the frogs. In summary, N. parkeri can tolerate a brief and partial freezing of their body, which was accompanied by substantial changes in metabolomic profiles after freezing exposure.
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Geiss L, do Amaral MCF, Frisbie J, Goldstein DL, Krane CM. Postfreeze viability of erythrocytes from Dryophytes chrysoscelis. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 331:308-313. [PMID: 30933437 DOI: 10.1002/jez.2262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/25/2022]
Abstract
Dryophytes chrysoscelis (formerly Hyla chrysoscelis, Cope's gray treefrog) is a freeze-tolerant anuran that accumulates glycerol and urea during cold acclimation and freezing. It is hypothesized that glycerol and urea function as cryoprotectants by minimizing osmotically induced cell damage during freezing and thawing, thereby improving the postfreeze viability of red blood cells (RBCs) when frozen in medium containing those solutes. To test this, erythrocytes were obtained from warm (22°C) and cold-acclimated (4°C) frogs and suspended in 280 mOsM phosphate-buffered saline (PBS). RBCs were frozen in 280 mOsM, isosmotic/isotonic, PBS, or in PBS made hyperosmotic by addition of 150 mM solutes. Postfreeze viability was determined with a hemolysis assay. Postfreeze viability of cells from warm-acclimated frogs improved from 18.9 ± 1.3% in PBS to 47.4 ± 5.2% in PBS with urea ( p < 0.01). The addition of other solutes (glycerol, glucose, NaCl, or sorbitol) had no effect. RBCs from cold-acclimated frogs had 45.8 ± 3.4% viability when frozen in 280 mOsM PBS, and this improved to 71.6 ± 8.9% or 71.9 ± 1.6%, respectively, when frozen with glycerol ( p < 0.01) or urea ( p < 0.001). The viability of RBCs from cold-acclimated frogs was not different between unfrozen cells 86.7-88.4%) and those frozen with glycerol (71.6 ± 8.9%, p > 0.05) or with urea (71.9 ± 1.6%, p > 0.05). These data suggest that (a) cold acclimation induces cellular changes in RBCs that result in improved postfreeze viability, and (b) glycerol and urea are part of a complex cryoprotectant system in D. chrysoscelis.
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Affiliation(s)
- Loren Geiss
- Department of Biology, University of Dayton, Dayton, Ohio
| | | | - James Frisbie
- Department of Biological Sciences, Wright State University, Dayton, Ohio
| | - David L Goldstein
- Department of Biological Sciences, Wright State University, Dayton, Ohio
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Hawkins LJ, Wang M, Zhang B, Xiao Q, Wang H, Storey KB. Glucose and urea metabolic enzymes are differentially phosphorylated during freezing, anoxia, and dehydration exposures in a freeze tolerant frog. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2019; 30:1-13. [PMID: 30710892 DOI: 10.1016/j.cbd.2019.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/19/2019] [Accepted: 01/21/2019] [Indexed: 02/08/2023]
Abstract
Vertebrate freeze tolerance requires multiple adaptations underpinned by specialized biochemistry. Freezing of extracellular water leads to intracellular dehydration as pure water is incorporated into growing ice crystals and also results in the cessation of blood supply to tissues, creating an anoxic cellular environment. Hence, the freeze tolerant wood frog, Rana sylvatica, must endure both dehydration and anoxia stresses in addition to freezing. The metabolic responses to freezing, dehydration and anoxia involve both protein/enzyme adaptations and the production of metabolites with metabolic or osmotic functions, particularly glucose and urea. The present study uses a phosphoproteome analysis to examine the differential phosphorylation of metabolic enzymes involved in the production of these two metabolites in liver in response to freezing, anoxia, or dehydration exposures. Our results show stress-specific responses in the abundance of phosphopeptides retrieved from nine glycolytic enzymes and three urea cycle enzymes in liver of wood frogs exposed to 24 h freezing, 24 h anoxia, or dehydration to 40% of total body water loss, as compared with 5 °C acclimated controls. Data show changes in the abundance of phosphopeptides belonging to glycogen phosphorylase (GP) and phosphofructokinase 2 (PFK2) that were consistent with differential phosphorylation control of glycogenolysis and a metabolic block at PFK1 that can facilitate glucose synthesis as the cryoprotectant during freezing. Anoxia-exposed animals showed similar changes in GP phosphorylation but no changes to PFK2; changes that would facilitate mobilization of glycogen as a fermentative fuel for anaerobic glycolysis. Urea is commonly produced as a compatible osmolyte in response to amphibian dehydration. Selected urea cycle enzymes showed small changes in phosphopeptide abundance in response to dehydration, but during freezing differential phosphorylation occurred that may facilitate this ATP expensive process when energy resources are sparse. These results add to the growing body of literature demonstrating the importance and efficiency of reversible protein phosphorylation as a regulatory mechanism allowing animals to rapidly respond to environmental stress.
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Affiliation(s)
- Liam J Hawkins
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada
| | - Minjing Wang
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Baowen Zhang
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Qi Xiao
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Hui Wang
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China.
| | - Kenneth B Storey
- Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6, Canada.
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Green SR, Storey KB. Purification of carbamoyl phosphate synthetase 1 (CPS1) from wood frog (Rana sylvatica) liver and its regulation in response to ice-nucleation and subsequent whole-body freezing. Mol Cell Biochem 2018; 455:29-39. [PMID: 30421312 DOI: 10.1007/s11010-018-3468-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/30/2018] [Indexed: 12/20/2022]
Abstract
Carbamoyl phosphate synthetase I (CPS1) represents an important regulatory enzyme of the urea cycle that mediates the ATP-driven reaction ligating ammonium, carbonate, and phosphate to form carbamoyl phosphate. The freeze-tolerant wood frog (Rana sylvatica or Lithobates sylvaticus) accumulates high concentrations of urea during bouts of freezing to detoxify any ammonia generated and to contribute as a cryoprotectant thereby helping to avoid freeze damage to cells. Purification of CPS1 to homogeneity from wood frog liver was performed in control and frozen wood frogs by a three-step chromatographic process. The affinity of CPS1 for its three substrates was tested in the purified control and freeze-exposed enzyme under a variety of conditions including the presence and absence of the natural cryoprotectants urea and glucose. The results demonstrated that affinity for ammonium was higher in the freeze-exposed CPS1 (1.26-fold) and that with the addition of 400 mM glucose it displayed higher affinity for ATP (1.30-fold) and the obligate activator N-acetylglutamate (1.24-fold). Denaturation studies demonstrated the freeze-exposed enzyme was less thermally stable than the control with an unfolding temperature approximately 1.5 °C lower (52.9 °C for frozen and 54.4 °C for control). The control form of CPS1 had a significantly higher degree of glutarylated lysine residues (1.42-fold increase) relative to the frozen. The results suggest that CPS1 activation and maintenance of urea cycle activity despite the hypometabolic conditions associated with freezing are important aspects in the metabolic survival strategies of the wood frog.
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Affiliation(s)
- Stuart R Green
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada.
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Costanzo JP. Overwintering adaptations and extreme freeze tolerance in a subarctic population of the wood frog, Rana sylvatica. J Comp Physiol B 2018; 189:1-15. [PMID: 30390099 DOI: 10.1007/s00360-018-1189-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/21/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
The terrestrially hibernating wood frog (Rana sylvatica) is well-known for its iconic freeze tolerance, an overwintering adaptation that has received considerable investigation over the past 35 years. Virtually, all of this research has concerned frogs indigenous to the temperate regions of its broad range within North America. However, recent investigations have shown that frogs of subarctic populations are extremely cold hardy, being capable of surviving freezing for longer periods and at much lower temperatures as compared to conspecifics from temperate regions. Their exceptional freeze tolerance is partly supported by an enhanced cryoprotectant system that uses very high levels of urea and glucose to limit ice formation, regulate metabolism, and protect macromolecules and cellular structures from freezing/thawing stresses. In the weeks before they begin hibernating, northern frogs undertake radical physiological transitions, such as depletion of fat stores and catabolism of muscle protein, that prime the cryoprotectant system by accruing urea and stockpiling glycogen from which glucose is mobilized during freezing. Concentrations of cryoprotectants ultimately achieved in Alaskan frogs when freezing occurs vary among tissues but generally are higher than those of frogs inhabiting milder climates. This review summarizes the molecular, biochemical, and physiological adaptations permitting this northern phenotype to survive the long and harsh winters of the region.
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Affiliation(s)
- Jon P Costanzo
- Department of Biology, Miami University, 45056, Oxford, OH, USA.
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Liu ZP, Gu WB, Tu DD, Zhu QH, Zhou YL, Wang C, Wang LZ, Shu MA. Effects of both cold and heat stresses on the liver of giant spiny frog Quasipaa spinosa: stress response and histological changes. J Exp Biol 2018; 221:jeb.186379. [DOI: 10.1242/jeb.186379] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/03/2018] [Indexed: 01/24/2023]
Abstract
Ambient temperature associated stress can affect the normal physiological functions in ectotherms. To assess the effects of cold or heat stress on amphibians, the giant spiny frogs, Quasipaa spinosa, were acclimated at 22 °C followed by being treated at 5 °C or 30 °C for 0, 3, 6, 12, 24 and 48 h, respectively. Histological alterations, apoptotic index, mitochondrial reactive oxygen species (ROS) generation, antioxidant activity indices and stress-response gene expressions in frog livers were subsequently determined. Results showed that many fat droplets appeared after 12 h of heat stress. Percentage of melanomacrophages centres significantly changed during 48 h at both stress conditions. Furthermore, the mitochondrial ROS levels were elevated in a time-dependent manner up to 6 h and 12 h in the cold and heat stress groups, respectively. The activities of superoxide dismutase, glutathione peroxidase and catalase were successively increased along the cold or heat exposure, and most of their gene expression levels showed similar changes at both stress conditions. Most tested HSP genes were sensitive to temperature exposure, and the expression profiles of most apoptosis-related genes was significantly up-regulated at 3 and 48 h under cold and heat stress, respectively. Apoptotic index at 48 h under cold stress was significantly higher than that under heat stress. Notably, lipid droplets, HSP30, HSP70 and HSP110 might be suitable bioindicators of heat stress. The results of these alterations at physiological, biochemical and molecular levels might contribute to a better understanding of the stress response of Q. spinosa and even amphibians under thermal stresses.
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Affiliation(s)
- Ze-Peng Liu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Wen-Bin Gu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Dan-Dan Tu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Qi-Hui Zhu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Yi-Lian Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Cong Wang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Lan-Zhi Wang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Miao-An Shu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
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Zhang Y, Al-attar R, Storey KB. TonEBP/NFAT5 regulates downstream osmoregulatory proteins during freeze-thaw stress in the wood frog. Cryobiology 2017; 79:43-49. [DOI: 10.1016/j.cryobiol.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 12/19/2022]
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Regulation of glutamate dehydrogenase (GDH) in response to whole body freezing in wood frog liver linked to differential acetylation and ADP-ribosylation. Arch Biochem Biophys 2017; 636:90-99. [DOI: 10.1016/j.abb.2017.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/11/2017] [Accepted: 10/14/2017] [Indexed: 12/31/2022]
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Abstract
Freeze tolerance is an amazing winter survival strategy used by various amphibians and reptiles living in seasonally cold environments. These animals may spend weeks or months with up to ∼65% of their total body water frozen as extracellular ice and no physiological vital signs, and yet after thawing they return to normal life within a few hours. Two main principles of animal freeze tolerance have received much attention: the production of high concentrations of organic osmolytes (glucose, glycerol, urea among amphibians) that protect the intracellular environment, and the control of ice within the body (the first putative ice-binding protein in a frog was recently identified), but many other strategies of biochemical adaptation also contribute to freezing survival. Discussed herein are recent advances in our understanding of amphibian and reptile freeze tolerance with a focus on cell preservation strategies (chaperones, antioxidants, damage defense mechanisms), membrane transporters for water and cryoprotectants, energy metabolism, gene/protein adaptations, and the regulatory control of freeze-responsive hypometabolism at multiple levels (epigenetic regulation of DNA, microRNA action, cell signaling and transcription factor regulation, cell cycle control, and anti-apoptosis). All are providing a much more complete picture of life in the frozen state.
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Affiliation(s)
| | - Janet M. Storey
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
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21
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De Oliveira RA, Budik S, Aurich C. Influence of partial or total replacement of glycerol by alternative cryoprotectants in Ghent freezing extender on post-thaw sperm quality in stallions. Reprod Domest Anim 2017; 52:715-721. [DOI: 10.1111/rda.12970] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/19/2017] [Indexed: 12/14/2022]
Affiliation(s)
- RA De Oliveira
- Artificial Insemination and Embryo Transfer; Vetmeduni Vienna; Vienna Austria
| | - S Budik
- Artificial Insemination and Embryo Transfer; Vetmeduni Vienna; Vienna Austria
| | - C Aurich
- Artificial Insemination and Embryo Transfer; Vetmeduni Vienna; Vienna Austria
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22
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Al-Attar R, Zhang Y, Storey KB. Osmolyte regulation by TonEBP/NFAT5 during anoxia-recovery and dehydration-rehydration stresses in the freeze-tolerant wood frog ( Rana sylvatica). PeerJ 2017; 5:e2797. [PMID: 28133564 PMCID: PMC5251939 DOI: 10.7717/peerj.2797] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 11/15/2016] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The wood frog, Rana sylvatica, tolerates freezing as a means of winter survival. Freezing is considered to be an ischemic/anoxic event in which oxygen delivery is significantly impaired. In addition, cellular dehydration occurs during freezing because water is lost to extracellular compartments in order to promote freezing. In order to prevent severe cell shrinkage and cell death, it is important for the wood frog to have adaptive mechanisms for osmoregulation. One important mechanism of cellular osmoregulation occurs through the cellular uptake/production of organic osmolytes like sorbitol, betaine, and myo-inositol. Betaine and myo-inositol are transported by the proteins BGT-1 and SMIT, respectively. Sorbitol on the other hand, is synthesized inside the cell by the enzyme aldose reductase. These three proteins are regulated at the transcriptional level by the transcription factor, NFAT5/TonEBP. Therefore, the objective of this study was to elucidate the role of NFAT5/TonEBP in regulating BGT-1, SMIT, and aldose reductase, during dehydration and anoxia in the wood frog muscle, liver, and kidney tissues. METHODS Wood frogs were subjected to 24 h anoxia-4 h recovery and 40% dehydration-full rehydration experiments. Protein levels of NFAT5, BGT-1, SMIT, and aldose reductase were studied using immunoblotting in muscle, liver, and kidney tissues. RESULTS Immunoblotting results demonstrated downregulations in NFAT5 protein levels in both liver and kidney tissues during anoxia (decreases by 41% and 44% relative to control for liver and kidney, respectively). Aldose reductase protein levels also decreased in both muscle and kidney tissues during anoxia (by 37% and 30% for muscle and kidney, respectively). On the other hand, BGT-1 levels increased during anoxia in muscle (0.9-fold compared to control) and kidney (1.1-fold). Under 40% dehydration, NFAT5 levels decreased in liver by 53%. Aldose reductase levels also decreased by 42% in dehydrated muscle, and by 35% in dehydrated liver. In contrast, BGT-1 levels increased by 1.4-fold in dehydrated liver. SMIT levels also increased in both dehydrated muscle and liver (both by 0.8-fold). DISCUSSION Overall, we observed that osmoregulation through an NFAT5-mediated pathway is both tissue- and stress-specific. In both anoxia and dehydration, there appears to be a general reduction in NFAT5 levels resulting in decreased aldose reductase levels, however BGT-1 and SMIT levels still increase in certain tissues. Therefore, the regulation of osmoregulatory genes during dehydration and anoxia occurs beyond the transcriptional level, and it possibly involves RNA processing as well. These novel findings on the osmoregulatory mechanisms utilized by the wood frog advances our knowledge of osmoregulation during anoxia and dehydration. In addition, these findings highlight the importance of using this model to study molecular adaptations during stress.
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Affiliation(s)
- Rasha Al-Attar
- Institute of Biochemistry, Departments of Biology and Chemistry, Carleton University , Ottawa , ON , Canada
| | - Yichi Zhang
- Institute of Biochemistry, Departments of Biology and Chemistry, Carleton University , Ottawa , ON , Canada
| | - Kenneth B Storey
- Institute of Biochemistry, Departments of Biology and Chemistry, Carleton University , Ottawa , ON , Canada
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LeMoine CMR, Walsh PJ. Evolution of urea transporters in vertebrates: adaptation to urea's multiple roles and metabolic sources. J Exp Biol 2015; 218:1936-45. [PMID: 26085670 DOI: 10.1242/jeb.114223] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the two decades since the first cloning of the mammalian kidney urea transporter (UT-A), UT genes have been identified in a plethora of organisms, ranging from single-celled bacteria to metazoans. In this review, focusing mainly on vertebrates, we first reiterate the multiple catabolic and anabolic pathways that produce urea, then we reconstruct the phylogenetic history of UTs, and finally we examine the tissue distribution of UTs in selected vertebrate species. Our analysis reveals that from an ancestral UT, three homologues evolved in piscine lineages (UT-A, UT-C and UT-D), followed by a subsequent reduction to a single UT-A in lobe-finned fish and amphibians. A later internal tandem duplication of UT-A occurred in the amniote lineage (UT-A1), followed by a second tandem duplication in mammals to give rise to UT-B. While the expected UT expression is evident in excretory and osmoregulatory tissues in ureotelic taxa, UTs are also expressed ubiquitously in non-ureotelic taxa, and in tissues without a complete ornithine-urea cycle (OUC). We posit that non-OUC production of urea from arginine by arginase, an important pathway to generate ornithine for synthesis of molecules such as polyamines for highly proliferative tissues (e.g. testis, embryos), and neurotransmitters such as glutamate for neural tissues, is an important evolutionary driving force for the expression of UTs in these taxa and tissues.
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Affiliation(s)
- Christophe M R LeMoine
- Department of Biology, Centre for Advanced Research in Environmental Genomics, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5
| | - Patrick J Walsh
- Department of Biology, Centre for Advanced Research in Environmental Genomics, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5
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24
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Driedzic WR. Rainbow smelt: the unusual case of cryoprotection by sustained glycerol production in an aquatic animal. J Comp Physiol B 2015; 185:487-99. [DOI: 10.1007/s00360-015-0903-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/12/2015] [Accepted: 04/19/2015] [Indexed: 12/18/2022]
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25
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Cryoprotectants and extreme freeze tolerance in a subarctic population of the wood frog. PLoS One 2015; 10:e0117234. [PMID: 25688861 PMCID: PMC4331536 DOI: 10.1371/journal.pone.0117234] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 12/19/2014] [Indexed: 01/29/2023] Open
Abstract
Wood frogs (Rana sylvatica) exhibit marked geographic variation in freeze tolerance, with subarctic populations tolerating experimental freezing to temperatures at least 10-13 degrees Celsius below the lethal limits for conspecifics from more temperate locales. We determined how seasonal responses enhance the cryoprotectant system in these northern frogs, and also investigated their physiological responses to somatic freezing at extreme temperatures. Alaskan frogs collected in late summer had plasma urea levels near 10 μmol ml-1, but this level rose during preparation for winter to 85.5 ± 2.9 μmol ml-1 (mean ± SEM) in frogs that remained fully hydrated, and to 186.9 ± 12.4 μmol ml-1 in frogs held under a restricted moisture regime. An osmolality gap indicated that the plasma of winter-conditioned frogs contained an as yet unidentified osmolyte(s) that contributed about 75 mOsmol kg-1 to total osmotic pressure. Experimental freezing to -8°C, either directly or following three cycles of freezing/thawing between -4 and 0°C, or -16°C increased the liver's synthesis of glucose and, to a lesser extent, urea. Concomitantly, organs shed up to one-half (skeletal muscle) or two-thirds (liver) of their water, with cryoprotectant in the remaining fluid reaching concentrations as high as 0.2 and 2.1 M, respectively. Freeze/thaw cycling, which was readily survived by winter-conditioned frogs, greatly increased hepatic glycogenolysis and delivery of glucose (but not urea) to skeletal muscle. We conclude that cryoprotectant accrual in anticipation of and in response to freezing have been greatly enhanced and contribute to extreme freeze tolerance in northern R. sylvatica.
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do Amaral MCF, Lee RE, Costanzo JP. Hepatocyte responses toin vitrofreezing and β-adrenergic stimulation: Insights into the extreme freeze tolerance of subarcticRana sylvatica. ACTA ACUST UNITED AC 2015; 323:89-96. [DOI: 10.1002/jez.1905] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 10/17/2014] [Accepted: 10/22/2014] [Indexed: 11/05/2022]
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Gankam Kengne F, Couturier BS, Soupart A, Decaux G. Urea minimizes brain complications following rapid correction of chronic hyponatremia compared with vasopressin antagonist or hypertonic saline. Kidney Int 2014; 87:323-31. [PMID: 25100046 DOI: 10.1038/ki.2014.273] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 06/12/2014] [Accepted: 06/13/2014] [Indexed: 01/04/2023]
Abstract
Hyponatremia is a common electrolyte disorder that carries significant morbidity and mortality. However, severe chronic hyponatremia should not be corrected rapidly to avoid brain demyelination. Vasopressin receptor antagonists (vaptans) are now being widely used for the treatment of hyponatremia along with other alternatives like hypertonic saline. Previous reports have suggested that, in some cases, urea can also be used to correct hyponatremia. Correction of severe hyponatremia with urea has never been compared to treatment with a vaptan or hypertonic saline with regard to the risk of brain complications in the event of a too rapid rise in serum sodium. Here, we compared the neurological outcome of hyponatremic rats corrected rapidly with urea, lixivaptan, and hypertonic saline. Despite similar increase in serum sodium obtained by the three drugs, treatment with lixivaptan or hypertonic saline resulted in a higher mortality than treatment with urea. Histological analysis showed that treatment with urea resulted in less pathological change of experimental osmotic demyelination than was induced by hypertonic saline or lixivaptan. This included breakdown of the blood-brain barrier, microglial activation, astrocyte demise, and demyelination. Thus, overcorrection of hyponatremia with urea resulted in significantly lower mortality and neurological impairment than the overcorrection caused by lixivaptan or hypertonic saline.
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Affiliation(s)
- Fabrice Gankam Kengne
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Bruno S Couturier
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Alain Soupart
- 1] Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium [2] Hopital de Tubize, Department of Internal Medicine, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Guy Decaux
- Erasme Hospital, Department of General Internal Medicine, Research Unit on Hydromineral Metabolism, Université Libre de Bruxelles, Bruxelles, Belgium
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Costanzo JP, do Amaral MCF, Rosendale AJ, Lee RE. Hibernation physiology, freezing adaptation and extreme freeze tolerance in a northern population of the wood frog. J Exp Biol 2013; 216:3461-73. [DOI: 10.1242/jeb.089342] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
We investigated hibernation physiology and freeze tolerance in a population of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA, near the northernmost limit of the species' range. Winter acclimatization responses included a 233% increase in the hepatic glycogen depot that was subsidized by fat body and skeletal muscle catabolism, and a rise in plasma osmolality that reflected accrual of urea (to 106±10 μmol ml−1) and an unidentified solute (to ~73 μmol ml−1). In contrast, frogs from a cool-temperate population (southern Ohio, USA) amassed much less glycogen, had a lower uremia (28±5 μmol ml−1) and apparently lacked the unidentified solute. Alaskan frogs survived freezing at temperatures as low as −16°C, some 10–13°C below those tolerated by southern conspecifics, and endured a 2-month bout of freezing at −4°C. The profound freeze tolerance is presumably due to their high levels of organic osmolytes and bound water, which limits ice formation. Adaptive responses to freezing (−2.5°C for 48 h) and subsequent thawing (4°C) included synthesis of the cryoprotectants urea and glucose, and dehydration of certain tissues. Alaskan frogs differed from Ohioan frogs in retaining a substantial reserve capacity for glucose synthesis, accumulating high levels of cryoprotectants in brain tissue, and remaining hyperglycemic long after thawing. The northern phenotype also incurred less stress during freezing/thawing, as indicated by limited cryohemolysis and lactate accumulation. Post-glacial colonization of high latitudes by R. sylvatica required a substantial increase in freeze tolerance that was at least partly achieved by enhancing their cryoprotectant system.
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Affiliation(s)
- Jon P. Costanzo
- Department of Zoology, Miami University, Oxford, OH 45056, USA
| | | | | | - Richard E. Lee
- Department of Zoology, Miami University, Oxford, OH 45056, USA
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30
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Costanzo JP, Lee RE. Avoidance and tolerance of freezing in ectothermic vertebrates. J Exp Biol 2013; 216:1961-7. [DOI: 10.1242/jeb.070268] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
Ectothermic vertebrates have colonized regions that are seasonally or perpetually cold, and some species, particularly terrestrial hibernators, must cope with temperatures that fall substantially below 0°C. Survival of such excursions depends on either freeze avoidance through supercooling or freeze tolerance. Supercooling, a metastable state in which body fluids remain liquid below the equilibrium freezing/melting point, is promoted by physiological responses that protect against chilling injury and by anatomical and behavioral traits that limit risk of inoculative freezing by environmental ice and ice-nucleating agents. Freeze tolerance evolved from responses to fundamental stresses to permit survival of the freezing of a substantial amount of body water under thermal and temporal conditions of ecological relevance. Survival of freezing is promoted by a complex suite of molecular, biochemical and physiological responses that limit cell death from excessive shrinkage, damage to macromolecules and membranes, metabolic perturbation and oxidative stress. Although freeze avoidance and freeze tolerance generally are mutually exclusive strategies, a few species can switch between them, the mode used in a particular instance of chilling depending on prevailing physiological and environmental conditions.
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Affiliation(s)
- Jon P. Costanzo
- Department of Zoology, Miami University, Oxford, OH 45056, USA
| | - Richard E. Lee
- Department of Zoology, Miami University, Oxford, OH 45056, USA
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Higgins SA, Swanson DL. Urea is not a universal cryoprotectant among hibernating anurans: evidence from the freeze-tolerant boreal chorus frog (Pseudacris maculata). Comp Biochem Physiol A Mol Integr Physiol 2012; 164:344-50. [PMID: 23142424 DOI: 10.1016/j.cbpa.2012.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/03/2012] [Accepted: 11/03/2012] [Indexed: 10/27/2022]
Abstract
Freeze-tolerant organisms accumulate a diversity of low molecular weight compounds to combat negative effects of ice formation. Previous studies of anuran freeze tolerance have implicated urea as a cryoprotectant in the wood frog (Lithobates sylvatica). However, a cryoprotective role for urea has been identified only for wood frogs, though urea accumulation is an evolutionarily conserved mechanism for coping with osmotic stress in amphibians. To identify whether multiple solutes are involved in freezing tolerance in the boreal chorus frog (Pseudacris maculata), we examined seasonal and freezing-induced variation in several potential cryoprotectants. We further tested for a cryoprotective role for urea by comparing survival and recovery from freezing in control and urea-loaded chorus frogs. Tissue levels of glucose, urea, and glycerol did not vary significantly among seasons for heart, liver, or leg muscle. Furthermore, no changes in urea or glycerol levels were detected with exposure to freezing temperatures in these tissues. Urea-loading increased tissue urea concentrations, but failed to enhance freezing survival or facilitate recovery from freezing in chorus frogs in this study, suggesting little role for urea as a natural cryoprotectant in this species. These data suggest that urea may not universally serve as a primary cryoprotectant among freeze-tolerant, terrestrially hibernating anurans.
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Affiliation(s)
- Steven A Higgins
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.
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Tattersall GJ, Sinclair BJ, Withers PC, Fields PA, Seebacher F, Cooper CE, Maloney SK. Coping with Thermal Challenges: Physiological Adaptations to Environmental Temperatures. Compr Physiol 2012; 2:2151-202. [DOI: 10.1002/cphy.c110055] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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van Aardt W, Weber RE. Respiration and hemoglobin function in the giant African bullfrogPyxicephalus adspersusTschudi (Anura: Pyxicephalidae) during rest, exercise and dormancy. AFR J HERPETOL 2010. [DOI: 10.1080/21564574.2010.521197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Swanson DL, Burdick SL. Overwintering Physiology and Hibernacula Microclimates of Blanchard's Cricket Frogs at Their Northwestern Range Boundary. COPEIA 2010. [DOI: 10.1643/cp-09-121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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