Review: A history and perspective of mitochondria in the context of anoxia tolerance

Hawrysh, Peter John; Myrka, Alexander M.; Buck, Leslie T.

doi:10.1016/j.cbpb.2022.110733

Cited by 6 publications

(7 citation statements)

References 261 publications

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“…Mitochondria generate the vast majority of ATP during normoxia, but in hypoxia or anoxia, their function is inhibited because O 2 is less available or lacking, which causes intracellular ATP levels to drop. In anoxia tolerant species, this decrease in ATP generation is accompanied by a suppression of processes consuming ATP in the cell, especially protein synthesis and ion‐motive membrane pumps, including the Na + /K + pump 1,14 . This restores the balance between ATP produced and consumed at a new lower steady‐state level, whereby fermentable energy stores last longer in hypoxia and cell integrity is maintained 1,13 .…”

Section: Anoxia and Metabolism: Rewiring Glycolysis And Mitochondrial...mentioning

confidence: 99%

“…In anoxia tolerant species, this decrease in ATP generation is accompanied by a suppression of processes consuming ATP in the cell, especially protein synthesis and ion‐motive membrane pumps, including the Na + /K + pump. 1 , 14 This restores the balance between ATP produced and consumed at a new lower steady‐state level, whereby fermentable energy stores last longer in hypoxia and cell integrity is maintained. 1 , 13 Interestingly, heart mitochondria in anoxia cold‐acclimated turtles maintain their integrity with no major changes in cristae surface or other morphological traits, 43 indicating that mitophagy 44 is not a response to anoxia, at least in the turtle heart.…”

Section: Anoxia and Metabolism: Rewiring Glycolysis And Mitochondrial...mentioning

confidence: 99%

“…1,9 For further details on these and other physiological responses to anoxia, the reader is referred to existing reviews. 1,[10][11][12][13][14] Because of the fascinating nature of such adaptations, understanding the underlying mechanisms that allow these vertebrate species but not others to survive O 2 deprivation has been the focus of many comparative physiologists over the years. The cornerstone of comparative physiology, the August Krogh principle stating that "For many problems there is an animal on which it can be most conveniently studied," has motivated the choice of extremely hypoxia tolerant vertebrates like turtles and crucian carp as model organisms to understand underlying mechanisms to hypoxia and anoxia tolerance.…”

Section: Introductionmentioning

confidence: 99%

“…As discussed later, the anoxic crucian carp largely avoids acidosis by a rare metabolic step converting lactate to neutral ethanol, 7,8 which is lost during sustained gill ventilation, 6 while the anoxic turtle mobilizes the calcium carbonate of the shell to buffer acidosis from circulating protons and lactate 1,9 . For further details on these and other physiological responses to anoxia, the reader is referred to existing reviews 1,10–14 …”

Section: Introductionmentioning

confidence: 99%

“… 1 , 9 For further details on these and other physiological responses to anoxia, the reader is referred to existing reviews. 1 , 10 , 11 , 12 , 13 , 14 …”

Section: Introductionmentioning

confidence: 99%

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New insights into survival strategies to oxygen deprivation in anoxia‐tolerant vertebrates

Fago

2022

Acta Physiologica

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Hypoxic environments pose a severe challenge to vertebrates and even short periods of oxygen deprivation are often lethal as they constrain aerobic ATP production. However, a few ectotherm vertebrates are capable of surviving long-term hypoxia or even anoxia with little or no damage. Among these, freshwater turtles and crucian carp are the recognized champions of anoxia tolerance, capable of overwintering in complete oxygen deprivation for months at freezing temperatures by entering a stable hypometabolic state. While all steps of the oxygen cascade are adjusted in response to oxygen deprivation, this review draws from knowledge of freshwater turtles and crucian carp to highlight mechanisms regulating two of these steps, namely oxygen transport in the blood and oxygen utilization in mitochondria during three sequential phases: before anoxia, when hypoxia develops, during anoxia, and after anoxia at reoxygenation. In cold hypoxia, reduced red blood cell concentration of ATP plays a crucial role in increasing blood oxygen affinity and/or reducing oxygen unloading to tissues, to adjust aerobic metabolism to decrease ambient oxygen. In anoxia, metabolic rewiring of oxygen utilization keeps largely unaltered NADH/NAD + ratios and limits ADP degradation and succinate buildup. These critical adjustments make it possible to restart mitochondrial respiration and energy production with little generation of reactive oxygen species at reoxygenation when oxygen is again available. Inhibition of key metabolic enzymes seems to play crucial roles in these responses, in particular mitochondrial complex V, although identifying the nature of such inhibition(s) in vivo remains a challenge for future studies.

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Section: Anoxia and Metabolism: Rewiring Glycolysis And Mitochondrial...mentioning

confidence: 99%

Section: Anoxia and Metabolism: Rewiring Glycolysis And Mitochondrial...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“… 1 , 9 For further details on these and other physiological responses to anoxia, the reader is referred to existing reviews. 1 , 10 , 11 , 12 , 13 , 14 …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations