نتایج جستجو برای: lifespan
تعداد نتایج: 15331 فیلتر نتایج به سال:
23 The evolution of lifespan is a central question in evolutionary biology, begging the question why 24 there is so large variation among taxa. Specifically, a central quest is to unravel proximate causes of 25 ageing. Here we show that the degree of unsaturation of liver fatty acids predicts maximum lifespan 26 in 107 bird species. In these birds, the degree of fatty acid unsaturation is posit...
The lifespan-reproduction trade-off under dietary restriction is sex-specific and context-dependent.
Adult dietary restriction (DR) extends lifespan, but the mechanisms that underlie this effect are not well understood. Many DR studies have demonstrated that lifespan extension tends to be accompanied by a reduction in female fecundity - a correlation widely interpreted as evidence that DR triggers an adaptive re - allocation of resources from reproduction to somatic maintenance. Yet, recent ev...
In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called "fairy circles" are unknown, although a number of hypotheses have been proposed. This paper provides a more complete descripti...
Explaining the strong variation in lifespan among organisms remains a major challenge in evolutionary biology. Whereas previous work has concentrated mainly on differences in selection regimes and selection pressures, we hypothesize that differences in genetic drift may explain some of this variation. We develop a model to formalize this idea and show that the strong positive relationship betwe...
The interest in health benefits associated with consumption of anti-oxidants has led to investigations examining the possibility that diets rich in anti-oxidants promote lifespan extension. Studies using the standard fruit fly (Drosophila melanogaster) model of longevity have shown that the antioxidants vitamin E and N-acetyl cysteine prolong lifespan. Turmeric is a spice which has been consume...
The lifespan of Caenorhabditis elegans is determined by various genetic and environmental factors. In this paper, spr-3, a C. elegans homologous gene of the mammalian neural restrictive silencing factor (NRSF/REST), is reported to be an important gene regulating lifespan of C. elegans. A deletion mutation of spr-3, spr-3(ok2525), or RNAi inhibition of spr-3 expression led to the short lifespan ...
Males and females have different routes to successful reproduction, resulting in sex differences in lifespan and age-specific allocation of reproductive effort. The trade-off between current and future reproduction is often resolved differently by males and females, and both sexes can be constrained in their ability to reach their sex-specific optima owing to intralocus sexual conflict. Such ge...
The PTEN tumour suppressor encodes a phosphatase, and its daf-18 orthologue in Caenorhabditis elegans negatively regulates the insulin/IGF-1 DAF-2 receptor pathway that influences lifespan in worms and other species. In order to identify new DAF-18 regulated pathways involved in aging, we initiated a candidate RNAi feeding screen for clones that lengthen lifespan. Here, we report that smg-1 ina...
It is often assumed, but not established, that the major neurodegenerative diseases, such as Parkinson's disease, are not just age-dependent (their incidence changes with time) but actually aging-dependent (their incidence is coupled to the process that determines lifespan). To determine a dependence on the aging process requires the joint probability distribution of disease onset and lifespan....
Restriction of nutrients in the adult diet extends lifespan across a diverse range of species, but less is known about the long-term effects of developmental dietary restriction. In particular, it is not known whether adult lifespan is influenced by developmental caloric restriction or macronutrient balance. We used the nutritional geometry approach to independently manipulate protein and carbo...
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