The association between age and telomere length is age-dependent: Evidence for a threshold model of telomere length maintenance.

Telomere length and dynamics are commonly used biomarkers of somatic state, yet the role of telomeres underlying the aging process is still debated. Indeed, to date, empirical evidence for an association between age and telomere length is mixed. Here, we test if the age-dependency of the association between age and telomere length can provide a potential explanation for the reported inconsistencies across studies.

Increased male-induced harm in response to female-limited selection: interactive effects between intra- and interlocus sexual conflict?

Interlocus sexual conflict (IRSC) occurs because of shared interactions that have opposite effects on male and female fitness. Typically, it is assumed that loci involved in IRSC have sex-limited expression and are thus not directly affected by selective pressures acting on the other sex. However, if loci involved in IRSC have pleiotropic effects in the other sex, intersexual selection can shape the evolutionary dynamics of conflict escalation and resolution, as well as the evolution of reproductive traits linked to IRSC loci, and vice versa.

Reproductive Strategies Affect Telomere Dynamics across the Life Course.

AbstractBecause parental care has a heritable basis, the benefits of receiving increased parental provisioning early in life are genetically linked to the costs of providing increased parental provisioning at adulthood. Reproductive strategies thus result in distinct cost-benefit syndromes across the life course that may shape individual health and aging trajectories. Here we used an artificial selection approach in Japanese quail () to test how reproductive strategies affect telomere length, a biomarker of somatic state, at different life stages.

Intergenerational Costs of Oxidative Stress: Reduced Fitness in Daughters of Mothers That Experienced High Levels of Oxidative Damage during Reproduction.

AbstractParental condition transfer effects occur when the parents' physiological state during reproduction affects offspring performance. Oxidative damage may mediate such effects, yet evidence that oxidative damage experienced by parents during reproduction negatively affects offspring fitness is scarce and limited to early life stages. We show in Japanese quail () that maternal levels of oxidative damage, measured during reproduction, negatively predict the number of offspring produced by daughters.

Sex-specific effects of experimental ectoparasite infestation on telomere length in great tit nestlings.

Telomere length is a biomarker of biological ageing and lifespan in various vertebrate taxa. Evidence is accumulating that telomeres shorten more rapidly when an individual is exposed to environmental stressors. Parasites are potent selective agents that can cause physiological stress directly or indirectly through the activation of the host's immune system.

Oxidative Stress Experienced during Early Development Influences the Offspring Phenotype.

AbstractOxidative stress (OS) experienced early in life can affect an individual's phenotype. However, its consequences for the next generation remain largely unexplored. We manipulated the OS level endured by zebra finches () during their development by transitorily inhibiting the synthesis of the key antioxidant glutathione ("early-high-OS").

Adaptive downregulation of pheomelanin-related Slc7a11 gene expression by environmentally induced oxidative stress.

Pheomelanin is a sulphur-containing yellow-to-reddish pigment whose synthesis consumes the main intracellular antioxidant (glutathione; GSH) and its precursor cysteine. Cysteine used for pheomelanogenesis cannot be used for antioxidant protection. We tested whether the expression of Slc7a11, the gene regulating the transport of cysteine to melanocytes for pheomelanogenesis, is environmentally influenced when cysteine/GSH are most required for antioxidant protection.

Measuring oxidative stress: the confounding effect of lipid concentration in measures of lipid peroxidation.

Lipid peroxidation products are widely used as markers of oxidative damage in the organism. To properly interpret the information provided by these markers, it is necessary to know potential sources of bias and control confounding factors. Here, we investigated the relationship between two indicators of lipid mobilization (circulating levels of triglycerides and cholesterol) and two common markers of oxidative damage (plasma levels of malondialdehyde and hydroperoxides; the latter estimated from the d-ROMs assay kit).

The level of an intracellular antioxidant during development determines the adult phenotype in a bird species: a potential organizer role for glutathione.

Life-history traits are often involved in trade-offs whose outcome would depend on the availability of resources but also on the state of specific molecular signals. Early conditions can influence trade-offs and program the phenotype throughout the lifetime, with oxidative stress likely involved in many taxa. Here we address the potential regulatory role of a single intracellular antioxidant in life-history trade-offs.

Covariation in oxidative stress markers in the blood of nestling and adult birds.

Interest in the imbalance between the production of reactive oxygen species and the state of the antioxidant machinery-that is, oxidative stress-has recently grown among comparative physiologists and evolutionary/behavioral ecologists. The number and types of markers used to estimate oxidative stress is, however, under debate. The study of covariation among these markers is necessary to better interpret the information content of each independent variable.