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Martin Jastroch, Sylvain Giroud, Perry Barrett, Fritz Geiser, Gerhard Heldmaier, Annika Herwig
Endothermic mammals and birds require intensive energy turnover to sustain high body temperatures and metabolic rates. To cope with energetic bottlenecks associated with the change of seasons, and to minimise energy expenditure, complex mechanisms and strategies, such as daily torpor and hibernation, are used. During torpor metabolic depression and low body temperatures save energy. However, these bouts of torpor lasting for hours to weeks are interrupted by active 'euthermic' phases with high body temperatures...
October 18, 2016: Journal of Neuroendocrinology
Ajit R Bhagwat, Sachin M Mukhedkar
No abstract text is available yet for this article.
September 2016: Indian Heart Journal
Yong Chen, Ruping Pan, Alexander Pfeifer
MicroRNAs (miRNAs) are small non-coding RNA molecules consisting of approximately 20 to 22 nucleotides. They play a very important role in the regulation of gene expression. miRNAs can be found in different species and a variety of organs and tissues including adipose tissue. There are two types of adipose tissue in mammals: White adipose tissue (WAT) is the largest energy storage, whereas brown adipose tissue (BAT) dissipates energy to maintain body temperature. BAT was first identified in hibernating animals and newborns as a defense against cold...
October 11, 2016: Pharmacology & Therapeutics
Kathrin H Dausmann, Lisa Warnecke
Torpor, the controlled depression of virtually all bodily function during scarce periods, was verified in primates under free-ranging conditions less than two decades ago. The large variety of different torpor patterns found both within and among closely related species is particularly remarkable. To help unravel the cause of these variable patterns, our review investigates primate torpor use within an evolutionary framework. First, we provide an overview of heterothermic primate species, focusing on the Malagasy lemurs, and discuss their use of daily torpor or hibernation in relation to habitat type and climatic conditions...
November 1, 2016: Physiology
Marcela Franco, Carolina Contreras, Ned J Place, Francisco Bozinovic, Roberto F Nespolo
Mammals of the Neotropics are characterized by a marked annual cycle of activity, which is accompanied by several physiological changes at the levels of the whole organism, organs and tissues. The physiological characterization of these cycles is important, as it gives insight on the mechanisms by which animals adjust adaptively to seasonality. Here we studied the seasonal changes in blood biochemical parameters in the relict South American marsupial Dromiciops gliroides ("monito del monte" or "little mountain monkey"), under semi-natural conditions...
October 2, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Theodore J Weller, Kevin T Castle, Felix Liechti, Cris D Hein, Michael R Schirmacher, Paul M Cryan
Understanding of migration in small bats has been constrained by limitations of techniques that were labor-intensive, provided coarse levels of resolution, or were limited to population-level inferences. Knowledge of movements and behaviors of individual bats have been unknowable because of limitations in size of tracking devices and methods to attach them for long periods. We used sutures to attach miniature global positioning system (GPS) tags and data loggers that recorded light levels, activity, and temperature to male hoary bats (Lasiurus cinereus)...
October 4, 2016: Scientific Reports
Yingying Han, Jinqi Zhan, Ying Xu, Fengwei Zhang, Zhengrong Yuan, Qiang Weng
The aim of the present study was to elucidate the regulatory role of cell proliferation and apoptosis in testicular development of wild Daurian ground squirrels during the breeding season (April), the non-breeding season (June) and before hibernation (September). Gross mass and hormonal analysis showed that the testis:body mass ratio and plasma testosterone concentration fluctuated seasonally, with a peak in April and lowest values in June. Similarly, spermatogenesis was fully developed in April but suppressed in June and September...
September 28, 2016: Reproduction, Fertility, and Development
James T Julian, Victoria A Gould, Gavin W Glenney, Robert P Brooks
Few studies have documented seasonal variation of Batrachochytrium dendrobatidis (Bd) infection rates in larval amphibians. We identified 4 natural populations of northern green frogs Lithobates clamitans melanota in Pennsylvania (USA) that contained Bd-infected tadpoles during post-wintering collections in May and June, after hibernating tadpoles had overwintered in wetlands. However, we failed to detect infected tadpoles at those wetlands when pre-wintering collections were made in late July through early September...
September 26, 2016: Diseases of Aquatic Organisms
Daniel Bryan, Ayman El-Shibiny, Zack Hobbs, Jillian Porter, Elizabeth M Kutter
Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E...
2016: Frontiers in Microbiology
Christina M Davy, Gabriela F Mastromonaco, Julia L Riley, James H Baxter-Gilbert, Heather Mayberry, Craig K R Willis
Although it is well documented that infectious diseases can pose threats to biodiversity, the potential long-term consequences of pathogen exposure on individual fitness and its effects on population viability have rarely been studied. Here, we tested the hypothesis that pathogen exposure causes physiological carry-over effects, using a pathogen that is uniquely suited to this question because the infection period is specific and time-limited. The fungus Pseudogymnoascus destructans causes white-nose syndrome (WNS) in hibernating bats, which either die due to the infection while hibernating, or recover following emergence from hibernation...
September 18, 2016: Conservation Biology: the Journal of the Society for Conservation Biology
James M Turner, Fritz Geiser
Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months...
September 16, 2016: Journal of Comparative Physiology. B, Biochemical, Systemic, and Environmental Physiology
Tengfei Liu, Ping Yang, Hong Chen, Yufei Huang, Yi Liu, Yasir Waqas, Nisar Ahmed, Xiaoya Chu, Qiusheng Chen
Important evolutionary and ecological consequences arise from the ability of female turtles to store viable spermatozoa for an extended period. Although previous morphological studies have observed the localization of spermatozoa in Pelodiscus sinensis oviduct, no systematic study on the identification of genes that are involved in long-term sperm storage has been performed. In this study, the oviduct of P. sinensis at different phases (reproductive and hibernation seasons) was prepared for RNA-Seq and gene expression profiling...
2016: Scientific Reports
Miroslav Flieger, Hana Bandouchova, Jan Cerny, Milada Chudíčková, Miroslav Kolarik, Veronika Kovacova, Natália Martínková, Petr Novák, Ondřej Šebesta, Eva Stodůlková, Jiri Pikula
Pathogenic and non-pathogenic related microorganisms differ in secondary metabolite production. Here we show that riboflavin overproduction by a fungal pathogen and its hyperaccumulation in affected host tissue exacerbates a skin infection to necrosis. In white-nose syndrome (WNS) skin lesions caused by Pseudogymnoascus destructans, maximum riboflavin concentrations reached up to 815 μg ml(-1), indicating bioaccumulation and lack of excretion. We found that high riboflavin concentrations are cytotoxic under conditions specific for hibernation, affect bats' primary fibroblasts and induce cell detachment, loss of mitochondrial membrane potential, polymerization of cortical actin, and cell necrosis...
2016: Scientific Reports
Alison H Doherty, Danielle M Roteliuk, Sara E Gookin, Ashley K McGrew, Carolyn J Broccardo, Keith W Condon, Jessica E Prenni, Samantha J Wojda, Gregory L Florant, Seth W Donahue
Periods of physical inactivity increase bone resorption and cause bone loss and increased fracture risk. However, hibernating bears, marmots, and woodchucks maintain bone structure and strength, despite being physically inactive for prolonged periods annually. We tested the hypothesis that bone turnover rates would decrease and bone structural and mechanical properties would be preserved in hibernating marmots (Marmota flaviventris). Femurs and tibias were collected from marmots during hibernation and in the summer following hibernation...
September 2016: Physiological and Biochemical Zoology: PBZ
Samantha M Logan, Kenneth B Storey
Mammalian hibernation is characterized by a general suppression of energy expensive processes and a switch to lipid oxidation as the primary fuel source. Glucose-responsive carbohydrate responsive element binding protein (ChREBP) has yet to be studied in hibernating organisms, which prepare for the cold winter months by feeding until they exhibit an obesity-like state that is accompanied by naturally-induced and completely reversible insulin resistance. Studying ChREBP expression and activity in the hibernating 13-lined ground squirrel is important to better understand the molecular mechanisms that regulate energy metabolism under cellular stress...
October 2016: Cryobiology
Karen Gjesing Welinder, Rasmus Hansen, Michael Toft Overgaard, Malene Brohus, Mads Sønderkær, Martin von Bergen, Ulrike Rolle-Kampczyk, Wolfgang Otto, Tomas L Lindahl, Karin Arinell, Alina L Evans, Jon E Swenson, Inge G Revsbech, Ole Frobert
Brown bears (Ursus arctos) hibernate for 5-7 months without eating, drinking, urinating and defecating at a metabolic rate of only 25% of the summer activity rate. Nonetheless, they emerge healthy and alert in spring. We quantified the biochemical adaptations for hibernation by comparing the proteome, metabolome, and hematologic features of blood from hibernating and active free-ranging subadult brown bears with a focus on conservation of health and energy. We found that total plasma protein concentration increased during hibernation, even though the concentrations of most individual plasma proteins decreased, as did the white blood cell types...
September 8, 2016: Journal of Biological Chemistry
Yichi Zhang, Oscar A Aguilar, Kenneth B Storey
Background. Mammalian hibernation in thirteen-lined ground squirrels (Ictidomys tridecemlineatus) is characterized by dramatic changes on a physiological and molecular level. During hibernation, mammalian hearts show a propensity to hypertrophy due to the need for increasing contractility to pump colder and more viscous blood. While cardiac hypertrophy is quite often a process characterized by decompensation, the ground squirrel studied is an excellent model of cardiac plasticity and cardioprotection under conditions of hypothermia and ischemia...
2016: PeerJ
A A Lakhina, L N Markevich, N M Zakharova, V N Afanasyev, I K Kolomiytseva, E E Fesenko
In hibernating Yakutian ground squirrels S. undulatus, the content of total phospholipids in the nuclei of liver increased by 40% compared to that in animals in summer. In torpid state, the amount of sphingomyelin increased almost 8 times; phosphatidylserine, 7 times; and cardiolipin, 4 times. In active "winter" ground squirrels, the amount of sphingomyelin, phosphatidylserine, and cardiolipin decreased compared to the hibernating individuals but remained high compared to the "summer" ones. The torpor state did not affect the amount of lysophosphatidylcholine and phosphatidylinositol...
July 2016: Doklady. Biochemistry and Biophysics
Malcolm Brinn, Katie O'Neill, Ian Musgrave, Brian Jc Freeman, Maciej Henneberg, Jaliya Kumaratilake
BACKGROUND: There is a paucity of detailed methods describing how to harvest and process motor neurons obtained from the adult rat spinal cord. NEW METHOD: Removal of intra-cardiac perfusion step. The spinal cord is extruded intact from the rat in under 60seconds post-decapitation then processed without differentiation of ventral and dorsal regions. The temperature during processing was maintained at room temperature (22°C) except during the Papain processing step where the temperature was increased to 30°C...
September 2, 2016: Journal of Neuroscience Methods
Yichi Zhang, Shannon N Tessier, Kenneth B Storey
Foxo4 and MyoG proteins regulate the transcription of numerous genes, including the E3 ubiquitin ligases MAFbx and MuRF1, which are activated in skeletal muscle under atrophy-inducing conditions. In the thirteen-lined ground squirrel, there is little muscle wasting that occurs during hibernation, a process characterized by bouts of torpor and arousal, despite virtual inactivity. Consequently, we were interested in studying the regulatory role of Foxo4 and MyoG on ubiquitin ligases throughout torpor-arousal cycles...
October 2016: Cryobiology
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