scholarly journals Age-related sex differences in body condition and telomere dynamics of red-sided garter snakes

2017 ◽  
Vol 284 (1852) ◽  
pp. 20162146 ◽  
Author(s):  
Nicky Rollings ◽  
Emily J. Uhrig ◽  
Randolph W. Krohmer ◽  
Heather L. Waye ◽  
Robert T. Mason ◽  
...  

Life-history strategies vary dramatically between the sexes, which may drive divergence in sex-specific senescence and mortality rates. Telomeres are tandem nucleotide repeats that protect the ends of chromosomes from erosion during cell division. Telomeres have been implicated in senescence and mortality because they tend to shorten with stress, growth and age. We investigated age-specific telomere length in female and male red-sided garter snakes, Thamnophis sirtalis parietalis . We hypothesized that age-specific telomere length would differ between males and females given their divergent reproductive strategies. Male garter snakes emerge from hibernation with high levels of corticosterone, which facilitates energy mobilization to fuel mate-searching, courtship and mating behaviours during a two to four week aphagous breeding period at the den site. Conversely, females remain at the dens for only about 4 days and seem to invest more energy in growth and cellular maintenance, as they usually reproduce biennially. As male investment in reproduction involves a yearly bout of physiologically stressful activities, while females prioritize self-maintenance, we predicted male snakes would experience more age-specific telomere loss than females. We investigated this prediction using skeletochronology to determine the ages of individuals and qPCR to determine telomere length in a cross-sectional study. For both sexes, telomere length was positively related to body condition. Telomere length decreased with age in male garter snakes, but remained stable in female snakes. There was no correlation between telomere length and growth in either sex, suggesting that our results are a consequence of divergent selection on life histories of males and females. Different selection on the sexes may be the physiological consequence of the sexual dimorphism and mating system dynamics displayed by this species.

2019 ◽  
Vol 97 (4) ◽  
pp. 328-334 ◽  
Author(s):  
Mirna N. Chahine ◽  
Simon Toupance ◽  
Sandy El-Hakim ◽  
Carlos Labat ◽  
Sylvie Gautier ◽  
...  

Short telomere length (TL) is associated with atherosclerotic cardiovascular disease (ACVD) and other age-related diseases. It is unclear whether these associations originate from having inherently short TL or a faster TL attrition before or during disease development. We proposed the blood-and-muscle model to assess TL dynamics throughout life course. Our objective was to measure TL in leukocytes (LTL) and in skeletal muscle (MTL), which served as a proxy of TL at birth. The delta (MTL–LTL) represented life-long telomere attrition. Blood draws and skeletal muscle biopsies were performed on 35 Lebanese individuals undergoing surgery. Following DNA extraction, LTL and MTL were measured by Southern blot. In every individual aged between 30 and 85 years, MTL was longer than LTL. With age, MTL and LTL decreased, but the delta (MTL–LTL) increased by 14 bp/year. We validated the blood-and-muscle model that allowed us to identify TL, TL at birth, and lifelong TL attrition in a cross-sectional study. This model can be used in larger cross-sectional studies to evaluate the association of telomere dynamics with age-related diseases onset and progression.


2021 ◽  
Vol 288 (1951) ◽  
pp. 20210271
Author(s):  
L. J. Fitzpatrick ◽  
M. Olsson ◽  
A. Pauliny ◽  
G. M. While ◽  
E. Wapstra

Emerging patterns suggest telomere dynamics and life history are fundamentally linked in endotherms through life-history traits that mediate the processes underlying telomere attrition. Unlike endotherms, ectotherms maintain the ability to lengthen somatic telomeres throughout life and the link between life-history strategies and ectotherm telomere dynamics is unknown. In a well-characterized model system ( Niveoscincus ocellatus ), we used long-term longitudinal data to study telomere dynamics across climatically divergent populations. We found longer telomeres in individuals from the cool highlands than those from the warm lowlands at birth and as adults. The key determinant of adult telomere length across populations was telomere length at birth, with population-specific effects of age and growth on adult telomere length. The reproductive effort had no proximate effect on telomere length in either population. Maternal factors influenced telomere length at birth in the warm lowlands but not the cool highlands. Our results demonstrate that life-history traits can have pervasive and context-dependent effects on telomere dynamics in ectotherms both within and between populations. We argue that these telomere dynamics may reflect the populations' different life histories, with the slow-growing cool highland population investing more into telomere lengthening compared to the earlier-maturing warm lowland population.


2002 ◽  
Vol 80 (8) ◽  
pp. 1334-1343 ◽  
Author(s):  
N Perfito ◽  
G Schirato ◽  
M Brown ◽  
J C Wingfield

Seasonal adjustments and individual responses to environmental perturbations have been well characterized in many passerine species but similar studies in other groups of birds are sparse. Larger-bodied and longer-lived avian species have different life-history strategies and different energy-storage and -utilization patterns. We investigated the response to capture stress in male and female Harlequin Ducks (Histrionicus histrionicus) during the breeding season on montane rivers and during moult on coastal waterways of Washington State. Females arrived at the breeding grounds in better condition and had a smaller rise in circulating corticosterone during 1 h of restraint than males. As the breeding season progressed, body condition declined in females and their adrenocortical response to acute stress became more pronounced. A potentially disruptive environmental condition, high river flow during the breeding season, was not associated with lower nesting success, lower body condition indices, or higher corticosterone levels (baseline or maximum concentration). The maximum corticosterone concentration reached over 1 h of restraint was negatively correlated with body condition in females during the breeding season. Lastly, males and females had similar adrenocortical responses to capture and handling during moult. We relate differential responses to acute stress between males and females to different selective pressures during the breeding season.


2011 ◽  
Vol 32 (3) ◽  
pp. 424-427 ◽  
Author(s):  
Karen Elgee ◽  
Gabriel Blouin-Demers

AbstractWe investigated sexual size dimorphism and trophic morphology dimorphism in Eastern Garter Snakes (Thamnophis sirtalis) to test predictions derived from the reproductive role hypothesis. Our first objective was to examine whether structures involved in feeding (head and jaws) are more divergent than body size. Female T. sirtalis were larger than males and had proportionally larger heads. Our second objective was to look for an advantage of large head size by examining the relationship between body condition and head size. Body condition was positively correlated with relative head size in T. sirtalis for both sexes, in agreement with the reproductive role hypothesis.


BMJ Open ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. e032513 ◽  
Author(s):  
Mirko Manchia ◽  
Pasquale Paribello ◽  
Carlo Arzedi ◽  
Alberto Bocchetta ◽  
Paola Caria ◽  
...  

IntroductionSevere psychiatric disorders are typically associated with a significant reduction in life expectancy compared with the general population. Among the different hypotheses formulated to explain this observation, accelerated ageing has been increasingly recognised as the main culprit. At the same time, telomere shortening is becoming widely accepted as a proxy molecular marker of ageing. The present study aims to fill a gap in the literature by better defining the complex interaction/s between inflammation, age-related comorbidities, telomere shortening and gut microbiota in psychiatric disorders.Methods and analysisA cross-sectional study is proposed, recruiting 40 patients for each of three different diagnostic categories (bipolar disorder, schizophrenia and major depressive disorder) treated at the Section of Psychiatry and at the Unit of Clinical Pharmacology of the University Hospital Agency of Cagliari (Italy), compared with 40 age-matched and sex-matched non-psychiatric controls. Each group includes individuals suffering, or not, from age-related comorbidities, to account for the impact of these medical conditions on the biological make-up of recruited patients. The inflammatory state, microbiota composition and telomere length (TL) are assessed.Ethics and disseminationThe study protocol was approved by the Ethics Committee of the University Hospital Agency of Cagliari (PG/2018/11693, 5 September 2018). The study is conducted in accordance with the principles of good clinical practice and the Declaration of Helsinki, and in compliance with the relevant Italian national legislation. Written, informed consent is obtained from all participants. Participation in the study is on a voluntary basis only. Patients will be part of the dissemination phase of the study results, during which a local conference will be organised and families of patients will also be involved. Moreover, findings will be published in one or more research papers and presented at national and international conferences, in posters or oral communications.


Author(s):  
Samuel S. Aguiar ◽  
Thiago S. Rosa ◽  
Rodrigo V. P. Neves ◽  
Patrício L. A. Leite ◽  
Larissa A. Maciel ◽  
...  

AbstractLower SIRT1 and insulin resistance are associated with accelerated telomere shortening. This study investigated whether the lifestyle of master athletes can attenuate these age-related changes and thereby slow aging. We compared insulin, SIRT1, and telomere length in highly trained male master athletes (n=52; aged 49.9±7.2 yrs) and age-matched non-athletes (n=19; aged 47.3±8.9 yrs). This is a cross-sectional study, in which all data were collected in one visit. Overnight fasted SIRT1 and insulin levels in whole blood were assessed using commercial kits. Relative telomere length was determined in leukocytes through qPCR analyses. Master athletes had higher SIRT1, lower insulin, and longer telomere length than age-matched non-athletes (p<0.05 for all). Insulin was inversely associated with SIRT1 (r=−0.38; p=0.001). Telomere length correlated positively with SIRT1 (r=0.65; p=0.001), whereas telomere length and insulin were not correlated (r=0.03; p=0.87). In conclusion, master athletes have higher SIRT1, lower insulin, and longer telomeres than age-matched non-athletes. Furthermore, SIRT1 was negatively associated with insulin and positively associated with telomere length. These findings suggest that in this sample of middle-aged participants reduced insulin, increased SIRT1 activity, and attenuation of biological aging are connected.


2019 ◽  
Vol 6 (6) ◽  
pp. 190420 ◽  
Author(s):  
Melissa Bateson ◽  
Abraham Aviv ◽  
Laila Bendix ◽  
Athanase Benetos ◽  
Yoav Ben-Shlomo ◽  
...  

Smoking is associated with shorter leucocyte telomere length (LTL), a biomarker of increased morbidity and reduced longevity. This association is widely interpreted as evidence that smoking causes accelerated LTL attrition in adulthood, but the evidence for this is inconsistent. We analysed the association between smoking and LTL dynamics in 18 longitudinal cohorts. The dataset included data from 12 579 adults (4678 current smokers and 7901 non-smokers) over a mean follow-up interval of 8.6 years. Meta-analysis confirmed a cross-sectional difference in LTL between smokers and non-smokers, with mean LTL 84.61 bp shorter in smokers (95% CI: 22.62 to 146.61). However, LTL attrition was only 0.51 bp yr −1 faster in smokers than in non-smokers (95% CI: −2.09 to 1.08), a difference that equates to only 1.32% of the estimated age-related loss of 38.33 bp yr −1 . Assuming a linear effect of smoking, 167 years of smoking would be required to generate the observed cross-sectional difference in LTL. Therefore, the difference in LTL between smokers and non-smokers is extremely unlikely to be explained by a linear, causal effect of smoking. Selective adoption, whereby individuals with short telomeres are more likely to start smoking, needs to be considered as a more plausible explanation for the observed pattern of telomere dynamics.


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