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Author: Trixie Nicole Lee
Publisher:
ISBN:
Category : Marmots
Languages : en
Pages : 240
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Book Description
The Arctic is home to animals that have taken adaptations to overwintering to extremes. In this dissertation, I have investigated one of these adaptations, hibernation, in two species from the Arctic, the Alaska marmot (Marmota broweri) and the arctic ground squirrel (Urocitellus parryii). The expression of hibernation under natural conditions in these species was compared by collecting body temperature records of free-living individuals. The Alaska marmot, a highly social species, demonstrated extreme synchrony in body temperature patterns among a family group, indicating a strong reliance on social thermoregulation. In contrast, the arctic ground squirrel was confirmed to be a solitary hibernator that reduces body temperature below freezing during torpor. Both species must produce heat when soil temperatures are significantly below freezing for most of the winter. At these subfreezing ambient temperatures, the arctic ground squirrel has shown an increasing reliance on nonlipid fuel during torpor, driving a loss of lean mass during hibernation of ~20%. I calibrated deuterium dilution to repeatedly estimate body composition in this species, which dramatically changes adiposity through its annual cycle, and used this technique to quantify lean mass loss throughout hibernation in a study of tissue metabolism. I also developed and applied the natural abundance of nitrogen and carbon stable isotopes as tools for monitoring differential tissue metabolism and differentiating mixed metabolic fuel use in the arctic ground squirrel. These data clarified the mechanism of change in nitrogen stable isotopes andd, indicated that hibernating ground squirrels rebuild organ tissues while breaking down muscle tissue to meet energetic demands. Furthermore, I corroborated a shift in metabolic fuel use toward nonlipid sources during torpor at low ambient temperatures by using the carbon isotope ratio in exhaled breath in combination with respiratory quotient. This dissertation combines studies of hibernation patterns in free-living animals with experimental data on the tissues and fuels being catabolized at very low temperatures to broaden our understanding of how small mammals successfully hibernate in severe winter conditions. It also presents the development and use of stable isotope ratios as physiological tools in hibernating species.
Author: Trixie Nicole Lee
Publisher:
ISBN:
Category : Marmots
Languages : en
Pages : 240
Get Book Here
Book Description
The Arctic is home to animals that have taken adaptations to overwintering to extremes. In this dissertation, I have investigated one of these adaptations, hibernation, in two species from the Arctic, the Alaska marmot (Marmota broweri) and the arctic ground squirrel (Urocitellus parryii). The expression of hibernation under natural conditions in these species was compared by collecting body temperature records of free-living individuals. The Alaska marmot, a highly social species, demonstrated extreme synchrony in body temperature patterns among a family group, indicating a strong reliance on social thermoregulation. In contrast, the arctic ground squirrel was confirmed to be a solitary hibernator that reduces body temperature below freezing during torpor. Both species must produce heat when soil temperatures are significantly below freezing for most of the winter. At these subfreezing ambient temperatures, the arctic ground squirrel has shown an increasing reliance on nonlipid fuel during torpor, driving a loss of lean mass during hibernation of ~20%. I calibrated deuterium dilution to repeatedly estimate body composition in this species, which dramatically changes adiposity through its annual cycle, and used this technique to quantify lean mass loss throughout hibernation in a study of tissue metabolism. I also developed and applied the natural abundance of nitrogen and carbon stable isotopes as tools for monitoring differential tissue metabolism and differentiating mixed metabolic fuel use in the arctic ground squirrel. These data clarified the mechanism of change in nitrogen stable isotopes andd, indicated that hibernating ground squirrels rebuild organ tissues while breaking down muscle tissue to meet energetic demands. Furthermore, I corroborated a shift in metabolic fuel use toward nonlipid sources during torpor at low ambient temperatures by using the carbon isotope ratio in exhaled breath in combination with respiratory quotient. This dissertation combines studies of hibernation patterns in free-living animals with experimental data on the tissues and fuels being catabolized at very low temperatures to broaden our understanding of how small mammals successfully hibernate in severe winter conditions. It also presents the development and use of stable isotope ratios as physiological tools in hibernating species.
Author: Larry Underwood
Publisher: Elsevier
ISBN: 0323152619
Category : Science
Languages : en
Pages : 390
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Book Description
Comparative Mechanisms of Cold Adaptation covers the proceedings of a symposium held at the Naval Arctic Research Laboratory in Barrow, Alaska in 1975 and 1976. The said symposium discusses the mechanisms of cold adaptation according to experts from different fields. The book covers topics related to cold adaptation, such as energy acquisition and utilization; mechanisms of thermal tolerance; the physiology and requirements of hibernation; and the role of neural inputs in cold adaptation. Topics also include cold-induced enzymatic adjustments; cold-induced responses in ectotherms and homeotherms; hormonal mechanisms; and plant adaptation to low temperatures. The text is recommended for biologists who would like to understand better the different mechanisms involved in cold adaptation and the importance of its study.
Author: Cynthia Carey
Publisher: CRC Press
ISBN: 0429715714
Category : Science
Languages : en
Pages : 539
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Book Description
Contributors present the newest information on ecological, physiological, neurological, cellular and biochemical mechanisms by which vertebrates deal with seasonal cold.
Author: Charles P Lyman
Publisher: Elsevier
ISBN: 0323138241
Category : Nature
Languages : en
Pages : 332
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Book Description
Hibernation and Torpor in Mammals and Birds explores the physiological factors that control hibernation and torpor in birds and mammals. This text covers topics ranging from metabolism in hibernation to the role of endocrines, respiration and acid-base state in hibernation, and theories of hibernation. This book is comprised of 14 chapters and begins with an overview of some clear-cut definitions and why mammals and birds hibernate. The reader is then introduced to the variations from euthermia that have been observed among birds and mammals. To give some structure to this listing, the approach is phylogenetic, starting with the birds and proceeding through the primitive to the more advanced mammals. Subsequent chapters explains the process of entering hibernation and the hibernating state, itself; capability of a species in natural hibernation to arouse from that state using self-generated heat; physiological changes at the start of a spontaneous arousal; and physiological mechanisms underlying the ability of hibernators to rewarm. Consideration is also given to intermediary metabolism in hibernation, cold adaptation of metabolism in hibernators, and the response of hibernators to various extrinsic influences such as neoplastic growth, radiation injury, and parasitism and symbionts. This book will be of interest to students and researchers in fields ranging from zoology to physiology and biophysics.
Author: Nicholas Mrosovsky
Publisher: Springer Science & Business Media
ISBN: 1468471767
Category : Science
Languages : en
Pages : 296
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Book Description
Mammalian hibernation is commonly thought of as something completely out of the ordinary, a "unique and unorthodox state." The present book takes the opposite view. It argues that the physiological achievements of hibernators do not deEend on special mechanisms but on special use of ordinary mechanisms. It is precisely this that makes the hibernators important. If the hibernators de pend on some unique physiological principle their study is that of a biological curio. But if they are using basic mammalian systems in a quantitatively extreme way, then they are a naturally occurring preparation of enormous potential. Hibernation involves every aspect of the animal's biology from fat metabo lism to behavior, from thermoregulation to dental caries; every system in the body is affected in some way or other by hibernation. A comprehensive account of hibernation would be almost coextensive with an account of the whole of mammalian biology. The present book does not attempt to describe everything that has been discovered about hibernation. Excellent coverage for that already exists in the proceedings of three recent symposia and in the other major source materials listed on page 233. There is in fact an enormous amount of information already available. But there is a difference between information and understanding. Despite the increasing volume of research and growing interest in mammalian hibernation, there is little appreciation of the essential characteristics of the phenomena. The pieces of the puzzle lie scattered.
Author: Sylvain Giroud
Publisher: Frontiers Media SA
ISBN: 2832550622
Category : Science
Languages : en
Pages : 138
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Book Description
Torpor or heterothermy corresponds to a state of depressed metabolism and is associated with specific metabolic, cellular and molecular adaptations that often occur on a seasonal basis. Yet the exact mechanisms and functioning of these changes are poorly understood. Interestingly, the potential of such extraordinary animal adaptation for human and animal health as well as other biomedical considerations has raised particular attention especially in the last decade. The strong metabolic and physiological adaptations of heterotherms can be of particular inspiration for current biomedical and pathological situations (e.g., obesity and related diseases, cardiovascular and metabolic dysfunctions, ischemia-reperfusion injuries, immune depression) and for the health and longevity of animal species, including humans.
Author: Gerhard Heldmaier
Publisher: Springer Science & Business Media
ISBN: 9783540674108
Category : Medical
Languages : en
Pages : 568
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Book Description
This book gives an up-to-date account of the current knowledge of cold adaptation in animals, including phenomena like hibernation, daily torpor, thermoregulation and thermogenesis, metabolic regulation, freeze tolerance, anaerobiosis, metabolic depression and related processes. For the next four years - until the 12th International Hibernation Symposium - it will serve as a state-of-the-art reference source for every scientist and graduate student working in these areas of physiology and zoology.
Author: Robert C. Roach
Publisher: Springer
ISBN: 0306480727
Category : Medical
Languages : en
Pages : 372
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Book Description
The International Hypoxia Symposium convenes biannually to bring together international experts from many fields to explore the state of the art in normal and pathophysiological responses to hypoxia. Representatives from five continents and 32 countries joined together in February 2003 for four days in the dramatic mountains of Banff, Alberta. As editors of the Proceedings of the International Hypoxia Symposia, we strive to maintain a 26 six year tradition of presenting a stimulating blend of clinical and basic science papers focused on hypoxia. Topics covered in 2003 include hibernation and hypoxia, hypoxia and fetal development and new advances in high altitude pathophysiology, oxidative stress and membrane damage, hypoxic regulation of blood flow, heat shock proteins in hypoxia, and future directions in hypoxia research. In 2003 we also had the privilege ofhonoring John W. Severinghaus as a friend, colleague, mentor and inspiration to many in the field. Tom Hornbein's personal tribute to John Severinghaus is the first chapter in this volume, followed by an entertaining update of the history of the discovery of oxygen written by John Severinghaus.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Book Description
We have discovered that mitochondrial proton conductance is unchanged during hibernation and that the reduced metabolism observed in hibernators is a partial consequence of tissue specific depression of substrate oxidation. Using proton leak analyses we show that increases in uncoupling protein 3 expression do not serve a thermogenic function. Rather uncoupling protein 3 likely protects against the accumulation of fatty acids in the mitochondrial matrix. The polyA binding protein-mRNA interactions observed previously in hibernating animals are also observed in explants from squirrels not hibernating. These data suggest that PABP-mRNA interactions are a consequence of cold temperature. Using a mouse cDNA array, we have discovered several additional candidate genes that appear upregulated during hibernation. The functional significance of this result is currently being determined. We have developed black bear cDNA libraries for the ultimate construction of a bear array that will be used in future comparative studies of hibernation.
Author: Thomas Ruf
Publisher: Springer Science & Business Media
ISBN: 364228678X
Category : Science
Languages : en
Pages : 549
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Book Description
This book summarises the newest information on seasonal adaptation in animals. Topics include animal hibernation, daily torpor, thermoregulation, heat production, metabolic depression, biochemical adaptations, neurophysiology and energy balance. The contributors to this book present interdisciplinary research at multiple levels ranging from the molecular to the ecophysiological, as well as evolutionary approaches. The chapters of this book provide original data not published elsewhere, which makes it the most up-to-date, comprehensive source of information on these fields. The book’s subchapters correspond to presentations given at the 14th International Hibernation Symposium in August 2012 in Austria. This is a very successful series of symposia (held every four years since 1959) that attracts leading researchers in the field. Like the past symposia, this meeting – and consequently the book – is aimed not only at hibernation but at covering the full range of animal adaptations to seasonal environments. For the next four years, this book will serve as the cutting-edge reference work for graduate students and scientists active in this field of physiology and ecology. .
