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Telomeres, the protective ends of chromosomes, progressively shorten due to incomplete mitotic replication and oxidative stress. In some organisms, transient telomere elongation may occur, for example, when individuals have an energy surplus to counter stress-induced life events or when elongating telomeres is a last chance to increase fitness. Mammalian hibernators are good models to test telomere dynamics, as they cycle between prolonged bouts of metabolic depression (torpor) punctuated by short surges to euthermia (arousals). We studied captive fat-tailed dwarf lemurs (Cheirogaleus medius), strepsirrhine primate hibernators, that were food-deprived (n= 8) or fed daily (n= 7) during hibernation (4.5 months). We compared telomere lengths, assayed via qPCR from oral swabs, at five strategic time points that span a full year. Food-deprived subjects underwent multi-day torpor/arousal cycles, lost considerable body mass and elongated telomeres during hibernation but shortened them upon emergence. In contrast, food-provisioned subjects ate daily, lost body mass more slowly, underwent shallower and shorter torpor bouts and experienced little change in telomere lengths during the same periods. Our results highlight a complex relationship between telomere dynamics, energy balance and torpor expression. Further investigation is warranted to elucidate the regulation of protective mechanisms in these primate hibernators.
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Cellular, Molecular, and Physiological Adaptations of Hibernation: The Solution to Environmental Challenges
Thriving in times of resource scarcity requires an incredible flexibility of behavioral, physiological, cellular, and molecular functions that must change within a relatively short time. Hibernation is a collection of physiological strategies that allows animals to inhabit inhospitable environments, where they experience extreme thermal challenges and scarcity of food and water. Many different kinds of animals employ hibernation, and there is a spectrum of hibernation phenotypes. Here, we focus on obligatory mammalian hibernators to identify the unique challenges they face and the adaptations that allow hibernators to overcome them. This includes the cellular and molecular strategies used to combat low environmental and body temperatures and lack of food and water. We discuss metabolic, neuronal, and hormonal cues that regulate hibernation and how they are thought to be coordinated by internal clocks. Last, we touch on questions that are left to be addressed in the field of hibernation research. Studies from the last century and more recent work reveal that hibernation is not simply a passive reduction in body temperature and vital parameters but rather an active process seasonally regulated at the molecular, cellular, and organismal levels.
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- PAR ID:
- 10232911
- Date Published:
- Journal Name:
- Annual Review of Cell and Developmental Biology
- Volume:
- 36
- Issue:
- 1
- ISSN:
- 1081-0706
- Page Range / eLocation ID:
- 315 to 338
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1146/annurev-cellbio-012820-095945
