Tissue metabolism of the ice-fish Chaenocephalus aceratus Loenberg

Bacila, Metry; Rosa, Rodrigo César; Rodrigues, Edson; Lucchiari, Pedro Hélio; Rosa, C D P da

doi:10.1016/0305-0491(89)90284-8

Cited by 7 publications

(2 citation statements)

References 18 publications

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“…( 24 )]. The very-low aerobic metabolism of these carnivores depends merely on oxygen diffusion over an enlarged gill surface from water to blood and from blood to tissues from a large vessel bed; a large heart, with cardiocytes and with an extreme mitochondrial density, pumps the blood through the vessel bed that is expanded to compensate for the limited oxygen carrying capacity of the plasma ( 26 ).…”

Section: Living In An Aquatic Nichementioning

confidence: 99%

Comparative Physiology of Energy Metabolism: Fishing for Endocrine Signals in the Early Vertebrate Pool

2017

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Energy is the common currency of life. To guarantee a homeostatic supply of energy, multiple neuro-endocrine systems have evolved in vertebrates; systems that regulate food intake, metabolism, and distribution of energy. Even subtle (lasting) dysregulation of the delicate balance of energy intake and expenditure may result in severe pathologies. Feeding-related pathologies have fueled research on mammals, including of course the human species. The mechanisms regulating food intake and body mass are well-characterized in these vertebrates. The majority of animal life is ectothermic, only birds and mammals are endotherms. What can we learn from a (comparative) study on energy homeostasis in teleostean fishes, ectotherms, with a very different energy budget and expenditure? We present several adaptation strategies in fish. In recent years, the components that regulate food intake in fishes have been identified. Although there is homology of the major genetic machinery with mammals (i.e., there is a vertebrate blueprint), in many cases this does not imply analogy. Although both mammals and fish must gain their energy from food, the expenditure of the energy obtained is different. Mammals need to spend vast amounts of energy to maintain body temperature; fishes seem to utilize a broader metabolic range to their advantage. In this review, we briefly discuss ecto- and endothermy and their consequences for energy balance. Next, we argue that the evolution of endothermy and its (dis-)advantages may explain very different strategies in endocrine regulation of energy homeostasis among vertebrates. We follow a comparative and evolutionary line of thought: we discuss similarities and differences between fish and mammals. Moreover, given the extraordinary radiation of teleostean fishes (with an estimated number of 33,400 contemporary species, or over 50% of vertebrate life forms), we also compare strategies in energy homeostasis between teleostean species. We present recent developments in the field of (neuro)endocrine regulation of energy balance in teleosts, with a focus on leptin.

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Section: Living In An Aquatic Nichementioning

confidence: 99%

Comparative Physiology of Energy Metabolism: Fishing for Endocrine Signals in the Early Vertebrate Pool

2017

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“…Understanding how fishes of the Channichthydae family, transport, supply and utilize O 2 as a final oxidizing agent in the respiratory processes, without the traditional respiratory pigments, has been an important question (Bacila et al 1989, Di Prisco 2000. Compared to the red blooded Antarctic fishes, icefishes have a more dense microvasculature and capillaries with wider luminal diameter (Fitch et al 1984, Eastman & Lannoo 2004, elevated number and mitochondrial density (Sidell 1998, O'Brien & Sidell 2000, and elevated cardiac debit (Sidell & O'Brien 2006).…”

Section: L-arginine Metabolismmentioning

confidence: 99%

Antarctic Fish Metabolic Responses as Potential Biomarkers of Environmental Impact

et al. 2011

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Most of the biochemical and physiological studies of Antarctic fish were directed to understand the molecular adaptation of these ectotherms to low temperatures and limits of their metabolic plasticity associated with thermal stress. The principal objective of this review is to discuss the energy metabolism, of L-arginine, antioxidant defense and the xenobiotics of Antarctic fishes as possible markers of environmental change. With the establishment of the circumpolar current and the physical isolation of the region, Antarctic fishes evolved under stable low temperatures. The elevated endemism, low diversity, and the probable stenothermality motivated a number of studies on Antarctic fishes. The presence of enzymes with physical and chemical properties adapted to low temperatures was evident in various studies and fortified the cold adaptation concept of these organisms. By ratifying the Antarctica Environmental Protection Treaty (Madrid protocol), the member countries committed themselves to monitoring the environment of the region. Though, it is one of the most pristine regions of the planet, increasing human activity in Antarctica has given rise to concerns about pollution from combustion oils, heavy metals and sewage. As the energy sustainability of the tissues requires that the velocity of the ATP generator systems should be in step with the energy demand, changes in the environment would lead to elevation in the energy demand of the organisms, which in turn demanded an adjustment of the ATP synthesis velocity. In these cases the enzymatic upregulation and downregulation have been used as biomarkers of the energy metabolism. Traditionally, the antioxidant defense enzymes and the xenobiotic metabolism of fishes have been used as biomarkers to access the natural or anthropic environmental change. However, these studies must correlate the levels of enzymes with the principal risk factors in the environmental pollution. L-arginine metabolism enzymes have been used as biomarkers of the physiological response in mammals, but there are few studies on Antarctic fishes. The central role of the amino acid L-arginine in the synthesis of nitric oxide, polyamines and as a signal in various physiological processes has drawn the attention of scientists. The tissue distribution and the isoforms distribution, along with its control via upregulation and downregulation of the arginase enzymes, nitric oxide synthase and ornithine decarboxylase in Antarctic fishes are potential biomarkers for environmental change. keywords: Antarctica; fish; biomarkers; metabolism; environment. resUMo respostAs MetAbÓlicAs De peiXes AntÁrticos coMo MArcADores De iMpActo AMbientAl. Boa parte dos estudos bioquímicos e fisiológicos com peixes Antárticos foram conduzidos objetivando entender a adaptação molecular desses organismos ectotérmicos às baixas temperaturas, bem como os limites da sua plasticidade metabólica associada com o estresse termal. O principal objetivo desta revisão

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New Lessons from an Old Fish: What Antarctic Icefishes May Reveal about the Functions of Oxygen-Binding Proteins

O’Brien

2016

Integr. Comp. Biol.

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The loss of expression of the oxygen-binding protein hemoglobin (Hb) in the family Channichthyidae (suborder Notothenioidei) of Antarctic fishes is considered a disaptation that has persisted because of the unusual conditions prevailing in the Southern Ocean during the evolution of the family. The loss of expression of the intracellular oxygen-binding protein myoglobin (Mb) in heart ventricles is more of a conundrum because it occurred at four points during the radiation of the family, suggesting weakened selective pressure maintaining expression of the protein. Yet, studies have shown that when present, Mb enhances function. Here, I discuss potential reasons for weakened selective pressure maintaining Mb expression in light of the multiple functions proposed for Mb. Additionally, I discuss results from recent studies exploring the possibility that the loss of Hb and Mb may be advantageous because it reduces the production of reactive oxygen species, levels of oxidized proteins, and the energetic costs associated with replacing oxidatively damaged proteins.

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Tissue metabolism of the ice-fish Chaenocephalus aceratus Loenberg

Cited by 7 publications

References 18 publications

Comparative Physiology of Energy Metabolism: Fishing for Endocrine Signals in the Early Vertebrate Pool

Comparative Physiology of Energy Metabolism: Fishing for Endocrine Signals in the Early Vertebrate Pool

Antarctic Fish Metabolic Responses as Potential Biomarkers of Environmental Impact

New Lessons from an Old Fish: What Antarctic Icefishes May Reveal about the Functions of Oxygen-Binding Proteins

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