ORCID Profile
0000-0001-8919-3117
Current Organisation
University of Veterinary Medicine Vienna
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Publisher: The Royal Society
Date: 23-04-2013
Abstract: Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis . Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining in idual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in sub-adults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Springer Science and Business Media LLC
Date: 11-2018
Publisher: The Company of Biologists
Date: 2016
DOI: 10.1242/JEB.137828
Abstract: Basking can substantially reduce thermoregulatory energy expenditure of mammals. We tested the hypothesis that the largely white winter fur of hamsters (Phodopus sungorus), originating from Asian steppes, may be related to camouflage to permit sun basking on or near snow. Winter-acclimated hamsters in our study were largely white and had a high proclivity to bask when resting and torpid. Resting hamsters reduced metabolic rate (MR) significantly (& %) when basking at ambient temperatures (Ta) of ∼15 and 0°C. Interestingly, body temperature (Tb) also was significantly reduced from 34.7±0.6°C (Ta 15°C not basking) to 30.4±2.0°C (Ta 0°C basking), which resulted in an extremely low (& % of predicted) apparent thermal conductance. Induced torpor (food withheld) during respirometry at Ta 15°C occurred on 83.3±36.0% of days and the minimum torpor MR was 36% of basal MR at an average Tb of 22.0±2.6°C movement to the basking l occurred at Tb& .0°C. Energy expenditure for rewarming was significantly reduced (by & %) during radiant heat-assisted rewarming, however, radiant heat per se without an endogenous contribution by animals did not strongly affect metabolism and Tb during torpor. Our data show that basking substantially modifies thermal energetics in hamsters, with a drop of resting Tb and MR not previously observed and a reduction of rewarming costs. The energy savings afforded by basking in hamsters suggest that this behaviour is of energetic significance not only for mammals living in deserts where basking is common, but also for P. sungorus and likely other cold-climate mammals.
Publisher: Wiley
Date: 15-10-2013
Publisher: Springer Science and Business Media LLC
Date: 23-04-2019
DOI: 10.1038/S41598-019-42756-Z
Abstract: Muscle nonshivering thermogenesis (NST) was recently suggested to play an important role in thermoregulation of species lacking brown adipose tissue (BAT). The mechanism, which is independent of muscle contractions, produces heat based on the activity of an ATPase pump in the sarcoplasmic reticulum (SERCA1a) and is controlled by the protein sarcolipin. To evaluate whether muscle NST could indeed play an important role in thermoregulation in species lacking BAT, we investigated the thermogenic capacities of newborn wild boar piglets. During cold exposure over the first 5 days of life, total heat production was improved while shivering intensity decreased, indicating an increasing contribution of NST. S ling skeletal muscle tissue for analyses of SERCA activity as well as gene expression of SERCA1a and sarcolipin, we found an age-related increase in all three variables as well as in body temperature. Hence, the improved thermogenesis during the development of wild boars is not due to shivering but explained by the observed increase in SERCA activity. Our results suggest that muscle NST may be the primary mechanism of heat production during cold stress in large mammals lacking BAT, strengthening the hypothesis that muscle NST has likely played an important role in the evolution of endothermy.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2016
DOI: 10.1038/SREP36856
Abstract: Telomere shortening is thought to be an important biomarker for life history traits such as lifespan and aging, and can be indicative of genome integrity, survival probability and the risk of cancer development. In humans and other animals, telomeres almost always shorten with age, with more rapid telomere attrition in short-lived species. Here, we show that in the edible dormouse ( Glis glis ) telomere length significantly increases from an age of 6 to an age of 9 years. While this finding could be due to higher survival of in iduals with longer telomeres, we also found, using longitudinal measurements, a positive effect of age on the rate of telomere elongation within older in iduals. To our knowledge, no previous study has reported such an effect of age on telomere lengthening. We attribute this exceptional pattern to the peculiar life-history of this species, which skips reproduction in years with low food availability. Further, we show that this “sit tight” strategy in the timing of reproduction is associated with an increasing likelihood for an in idual to reproduce as it ages. As reproduction could facilitate telomere attrition, this life-history strategy may have led to the evolution of increased somatic maintenance and telomere elongation with increasing age.
No related grants have been discovered for Claudia Bieber.