Embracing covariation in brain evolution: Large brains, extended development, and flexible primate social systems

PubMed Central

Charvet, Christine J.; Finlay, Barbara L.

2012-01-01

Brain size, body size, developmental length, life span, costs of raising offspring, behavioral complexity, and social structures are correlated in mammals due to intrinsic life-history requirements. Dissecting variation and direction of causation in this web of relationships often draw attention away from the factors that correlate with basic life parameters. We consider the “social brain hypothesis,” which postulates that overall brain and the isocortex are selectively enlarged to confer social abilities in primates, as an example of this enterprise and pitfalls. We consider patterns of brain scaling, modularity, flexibility of brain organization, the “leverage,” and direction of selection on proposed dimensions. We conclude that the evidence supporting selective changes in isocortex or brain size for the isolated ability to manage social relationships is poor. Strong covariation in size and developmental duration coupled with flexible brains allow organisms to adapt in variable social and ecological environments across the life span and in evolution. PMID:22230623

Revisiting the Great Lessons. Spotlight: Cosmic Education.

ERIC Educational Resources Information Center

Chattin-McNichols, John

2002-01-01

Considers the role of the Great Lessons--formation of the universe, evolution of life, evolution of humans, and discovery of language and mathematics--in the Montessori elementary curriculum. Discusses how the Great Lessons guide and organize the curriculum, as well as the timing of the lessons across the 6-12 age span. (JPB)

Vaccination and reduced cohort duration can drive virulence evolution: Marek's disease virus and industrialized agriculture.

PubMed

Atkins, Katherine E; Read, Andrew F; Savill, Nicholas J; Renz, Katrin G; Islam, A F M Fakhrul; Walkden-Brown, Stephen W; Woolhouse, Mark E J

2013-03-01

Marek's disease virus (MDV), a commercially important disease of poultry, has become substantially more virulent over the last 60 years. This evolution was presumably a consequence of changes in virus ecology associated with the intensification of the poultry industry. Here, we assess whether vaccination or reduced host life span could have generated natural selection, which favored more virulent strains. Using previously published experimental data, we estimated viral fitness under a range of cohort durations and vaccine treatments on broiler farms. We found that viral fitness maximized at intermediate virulence, as a result of a trade-off between virulence and transmission previously reported. Our results suggest that vaccination, acting on this trade-off, could have led to the evolution of increased virulence. By keeping the host alive, vaccination prolongs infectious periods of virulent strains. Improvements in host genetics and nutrition, which reduced broiler life spans below 50 days, could have also increased the virulence of the circulating MDV strains because shortened cohort duration reduces the impact of host death on viral fitness. These results illustrate the dramatic impact anthropogenic change can potentially have on pathogen virulence. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

The Limits of Life in the Deep Subsurface - Implications for the Origin of Life

NASA Astrophysics Data System (ADS)

Baross, John

2013-06-01

There are very few environments on Earth where life is absent. Microbial life has proliferated into habitats that span nearly every imaginable physico-chemical variable. Only the availability of liquid water and temperature are known to prevent the growth of organisms. The other extreme physical and chemical variables, such as pH, pressure, high concentrations of solutes, damaging radiation, and toxic metals, are life-prohibiting factors for most organisms but not for all. The deep subsurface environments span all of the extreme conditions encountered by life including habitat conditions not yet explored, such as those that combine high temperature, high and low pH and extreme pressures. Some of the ``extremophile'' microorganisms inhabiting the deep subsurface environments have been shown to be among the most ``ancient'' of extant life. Their genomes and physiologies have led to a broader understanding of the geological settings of early life, the most ancient energy pathways, and the importance of water/rock interactions and tectonics in the origin and early evolution of life. The case can now be made that deep subsurface environments contributed to life's origin and provided the habitat(s) for the earliest microbial communities. However, there is much more to be done to further our understanding on the role of moderate to high pressures and temperatures on the chemical and biochemical ``steps'' leading to life, and on the evolution and physiology of both ancient and present-day subsurface microbial communities.

Age- and Diet-Specific Effects of Variation at S6 Kinase on Life History, Metabolic, and Immune Response Traits in Drosophila melanogaster

PubMed Central

Cho, Irene; Horn, Lucas; Felix, Tashauna M.; Foster, Leanne; Gregory, Gwendolyn; Starz-Gaiano, Michelle; Chambers, Michelle M.

2010-01-01

Life history theory hypothesizes that genetically based variation in life history traits results from alleles that alter age-specific patterns of energy allocation among the competing demands of reproduction, storage, and maintenance. Despite the important role that alleles with age-specific effects must play in life history evolution, few naturally occurring alleles with age-specific effects on life history traits have been identified. A recent mapping study identified S6 kinase (S6k) as a candidate gene affecting lipid storage in Drosophila. S6k is in the target of rapamycin pathway, which regulates cell growth in response to nutrient availability and has also been implicated to influence many life history traits from fecundity to life span. In this article, we used quantitative complementation tests to examine the effect of allelic variation at S6k on a range of phenotypes associated with metabolism and fitness in an age-, diet-, and sex-specific manner. We found that alleles of S6k have pleiotropic effects on total protein levels, glycogen storage, life span, and the immune response and demonstrate that these allelic effects are age, diet, and sex specific. As many of the genes in the target of rapamycin pathway are evolutionarily conserved, our data suggest that genes in this pathway could play a pivotal role in life history evolution in a wide range of taxa. PMID:20491566

A unique life history among tetrapods: An annual chameleon living mostly as an egg

PubMed Central

Karsten, Kristopher B.; Andriamandimbiarisoa, Laza N.; Fox, Stanley F.; Raxworthy, Christopher J.

2008-01-01

The ≈28,300 species of tetrapods (four-limbed vertebrates) almost exclusively have perennial life spans. Here, we report the discovery of a remarkable annual tetrapod from the arid southwest of Madagascar: the chameleon Furcifer labordi, with a posthatching life span of just 4–5 months. At the start of the active season (November), an age cohort of hatchlings emerges; larger juveniles or adults are not present. These hatchlings grow rapidly, reach sexual maturity in less than 2 months, and reproduce in January–February. After reproduction, senescence appears, and the active season concludes with population-wide adult death. Consequently, during the dry season, the entire population is represented by developing eggs that incubate for 8–9 months before synchronously hatching at the onset of the following rainy season. Remarkably, this chameleon spends more of its short annual life cycle inside the egg than outside of it. Our review of tetrapod longevity (>1,700 species) finds no others with such a short life span. These findings suggest that the notorious rapid death of chameleons in captivity may, for some species, actually represent the natural adult life span. Consequently, a new appraisal may be warranted concerning the viability of chameleon breeding programs, which could have special significance for species of conservation concern. Additionally, because F. labordi is closely related to other perennial species, this chameleon group may prove also to be especially well suited for comparative studies that focus on life history evolution and the ecological, genetic, and/or hormonal determinants of aging, longevity, and senescence. PMID:18591659

A unique life history among tetrapods: an annual chameleon living mostly as an egg.

PubMed

Karsten, Kristopher B; Andriamandimbiarisoa, Laza N; Fox, Stanley F; Raxworthy, Christopher J

2008-07-01

The approximately 28,300 species of tetrapods (four-limbed vertebrates) almost exclusively have perennial life spans. Here, we report the discovery of a remarkable annual tetrapod from the arid southwest of Madagascar: the chameleon Furcifer labordi, with a posthatching life span of just 4-5 months. At the start of the active season (November), an age cohort of hatchlings emerges; larger juveniles or adults are not present. These hatchlings grow rapidly, reach sexual maturity in less than 2 months, and reproduce in January-February. After reproduction, senescence appears, and the active season concludes with population-wide adult death. Consequently, during the dry season, the entire population is represented by developing eggs that incubate for 8-9 months before synchronously hatching at the onset of the following rainy season. Remarkably, this chameleon spends more of its short annual life cycle inside the egg than outside of it. Our review of tetrapod longevity (>1,700 species) finds no others with such a short life span. These findings suggest that the notorious rapid death of chameleons in captivity may, for some species, actually represent the natural adult life span. Consequently, a new appraisal may be warranted concerning the viability of chameleon breeding programs, which could have special significance for species of conservation concern. Additionally, because F. labordi is closely related to other perennial species, this chameleon group may prove also to be especially well suited for comparative studies that focus on life history evolution and the ecological, genetic, and/or hormonal determinants of aging, longevity, and senescence.

A Phylogenomic Census of Molecular Functions Identifies Modern Thermophilic Archaea as the Most Ancient Form of Cellular Life

PubMed Central

Kim, Kyung Mo; Caetano-Anollés, Gustavo

2014-01-01

The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO) definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent. PMID:25249790

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, Heather R.; Thanathibodee, Thanawuth; Frebel, Anna

Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 Å) that is measurable in stars of low metallicity. Using archival Hubble Space Telescope-Space Telescope Imaging Spectrograph spectra, we have measured P abundances in 13 stars spanning –3.3 ≤ [Fe/H] ≤ -0.2, and obtained an upper limit for a star with [Fe/H] ∼ -3.8. Combined with the only other sample of P abundances inmore » solar-type stars in the literature, which spans a range of –1 ≤ [Fe/H] ≤ +0.2, we compare the stellar data to chemical evolution models. Our results support previous indications that massive-star P yields may need to be increased by a factor of a few to match stellar data at all metallicities. Our results also show that hypernovae were important contributors to the P production in the early universe. As P is one of the key building blocks of life, we also discuss the chemical evolution of the important elements to life, C-N-O-P-S, together.« less

EVOLUTION OF SARCOMA 37 IN CF1 RATS. BIOLOGICAL ASPECTS OF THE SPONTANEOUS CURE OF TUMORS STUDIED AFTER IRRADIATION AND ADMINISTRATION OF IMMUNE SERUM. Evolucao do sarcoma 37 em muganhos CF1. Aspectos biologicos da cura espontianea do tumor estudados apos irradiacao e administracao de soro imune (in Portuguese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clode, William H.

Transplants of sarcoma 37 were studied in regard to spontaneous regression of the tumor after irradiation and after the administration of immune serum. The following results were obtained: 1. Of 809 animals, 99% developed the tumor after transplantation; 2. The number of cells transplanted did not influence the growth rate, the percentage of spontaneous regressions, or the life spans of the animals; 3. Reimplantation of the tumor into mice which had previously rejected the tumor resulted in very few successful transplants; 4. The resistance of these mice to further attempts at implantation could not be altered by previous irradiation; 5.more » Animals transplanted for the first time suffer a faster evolution of the tumor, shortened life span, and a diminution of spontaneous regressions if they have been irradiated prior to transplantation (400r whole body); and, 6. Resistance to tumor growth could not be transferred passively in serum of mice which had rejected the tumor.« less

Yardang evolution from maturity to demise

NASA Astrophysics Data System (ADS)

Barchyn, Thomas E.; Hugenholtz, Chris H.

2015-07-01

Yardangs are enigmatic wind-parallel ridges sculpted by aeolian processes that are found extensively in arid environments on Earth and Mars. No general theory exists to explain the long-term evolution of yardangs, curtailing modeling of landscape evolution and dynamics of suspended sediment release. We present a hypothesis of yardang evolution using relative rates of sediment flux, interyardang corridor downcutting, yardang denudation, substrate erodibility, and substrate clast content. To develop and sustain yardangs, corridor downcutting must exceed yardang vertical denudation and deflation. However, erosion of substrate yields considerable quantities of sediment that shelters corridors, slowing downcutting. We model the evolution of yardangs through various combinations of rates and substrate compositions, demonstrating the life span, suspended sediment release, and resulting landscape evolution. We find that yardangs have a distinct and predictable evolution, with inevitable demise and unexpectedly dynamic and autogenic erosion rates driven by subtle differences in substrate clast composition.

Mice Producing Reduced Levels of Insulin-Like Growth Factor Type 1 Display an Increase in Maximum, but not Mean, Life Span

PubMed Central

2014-01-01

Reduced signaling through the IGF type 1 (IGF-1) receptor increases life span in multiple invertebrate organisms. Studies on mammalian longevity suggest that reducing levels of IGF-1 may also increase life span. However, the data are conflicting and complicated by the physiology of the mammalian neuroendocrine system. We have performed life-span analysis on mice homozygous for an insertion in the Igf1 gene. These mice produce reduced levels of IGF-1 and display a phenotype consistent with a significant decrease in IGF-1. Life-span analysis was carried out at three independent locations. Although the life-span data varied between sites, the maximum life span of the IGF-1-deficient mice was significantly increased and age-specific mortality rates were reduced in the IGF-1-deficient mice; however, mean life span did not differ except at one site, where mean life span was increased in female IGF-1-deficient animals. Early life mortality was noted in one cohort of IGF-1-deficient mice. The results are consistent with a significant role for IGF-1 in the modulation of life span but contrast with the published life-span data for the hypopituitary Ames and Snell dwarf mice and growth hormone receptor null mice, indicating that a reduction in IGF-1 alone is insufficient to increase both mean and maximal life span in mice. PMID:23873963

Life span in online communities

NASA Astrophysics Data System (ADS)

Grabowski, A.; Kosiński, R. A.

2010-12-01

Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of users’ activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the users’ lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation.

Life span in online communities.

PubMed

Grabowski, A; Kosiński, R A

2010-12-01

Recently online communities have attracted great interest and have become an important medium of information exchange between users. The aim of this work is to introduce a simple model of the evolution of online communities. This model describes (a) the time evolution of users' activity in a web service, e.g., the time evolution of the number of online friends or written posts, (b) the time evolution of the degree distribution of a social network, and (c) the time evolution of the number of active users of a web service. In the second part of the paper we investigate the influence of the users' lifespan (i.e., the total time in which they are active in an online community) on the process of rumor propagation in evolving social networks. Viral marketing is an important application of such method of information propagation.

Why the bigger live longer and travel farther: animals, vehicles, rivers and the winds.

PubMed

Bejan, Adrian

2012-01-01

Here we show that constructal-law physics unifies the design of animate and inanimate movement by requiring that larger bodies move farther, and their movement on the landscape last longer. The life span of mammals must scale as the body mass (M) raised to the power 1/4, and the distance traveled during the lifetime must increase with body size. The same size effect on life span and distance traveled holds for the other flows that move mass on earth: atmospheric and oceanic jets and plumes, river basins, animals and human operated vehicles. The physics is the same for all flow systems on the landscape: the scaling rules of "design" are expressions of the natural tendency of all flow systems to generate designs that facilitate flow access. This natural tendency is the constructal law of design and evolution in nature. Larger bodies are more efficient movers of mass on the landscape.

Little evidence for intralocus sexual conflict over the optimal intake of nutrients for life span and reproduction in the black field cricket Teleogryllus commodus.

PubMed

Rapkin, James; Archer, C Ruth; Grant, Charles E; Jensen, Kim; House, Clarissa M; Wilson, Alastair J; Hunt, John

2017-09-01

There is often large divergence in the effects of key nutrients on life span (LS) and reproduction in the sexes, yet nutrient intake is regulated in the same way in males and females given dietary choice. This suggests that the sexes are constrained from feeding to their sex-specific nutritional optima for these traits. Here, we examine the potential for intralocus sexual conflict (IASC) over optimal protein and carbohydrate intake for LS and reproduction to constrain the evolution of sex-specific nutrient regulation in the field cricket, Teleogryllus commodus. We show clear sex differences in the effects of protein and carbohydrate intake on LS and reproduction and strong positive genetic correlations between the sexes for the regulated intake of these nutrients. However, the between-sex additive genetic covariance matrix had very little effect on the predicted evolutionary response of nutrient regulation in the sexes. Thus, IASC appears unlikely to act as an evolutionary constraint on sex-specific nutrient regulation in T. commodus. This finding is supported by clear sexual dimorphism in the regulated intake of these nutrients under dietary choice. However, nutrient regulation did not coincide with the nutritional optima for LS or reproduction in either sex, suggesting that IASC is not completely resolved in T. commodus. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Ancestral populations perform better in a novel environment: domestication of medfly populations from five global regions

PubMed Central

Diamantidis, Alexandros D.; Carey, James R.; Nakas, Christos T.; Papadopoulos, Nikos T.

2010-01-01

Geographically isolated populations of a species may differ in several aspects of life-history, morphology, behavior, and genetic structure as a result of adaptation in ecologically diverse habitats. We used a global invasive species, the Mediterranean fruit fly to investigate, whether adaptation to a novel environment differs among geographically isolated populations that vary in major life history components such as life span and reproduction. We used wild populations from five global regions (Kenya, Hawaii, Guatemala, Portugal, and Greece). Adult demographic traits were monitored in F2, F5, F7 and F9 generations in captivity. Although domestication in constant laboratory conditions had a different effect on the mortality and reproductive rates of the different populations, a general trend of decreasing life span and age of first reproduction was observed for most medfly populations tested. However, taking into account longevity of both sexes, age-specific reproductive schedules, and average reproductive rates we found that the ancestral Kenyan population kept the above life history traits stable during domestication compared to the other populations tested. These findings provide important insights in the life-history evolution of this model species, and suggest that ancestral medfly populations perform better than the derived – invasive ones in a novel environment. PMID:21278856

The Chemical Evolution of Phosphorus

NASA Astrophysics Data System (ADS)

Jacobson, Heather R.; Thanathibodee, Thanawuth; Frebel, Anna; Roederer, Ian U.; Cescutti, Gabriele; Matteucci, Francesca

2014-12-01

Phosphorus is one of the few remaining light elements for which little is known about its nucleosynthetic origin and chemical evolution, given the lack of optical absorption lines in the spectra of long-lived FGK-type stars. We have identified a P I doublet in the near-ultraviolet (2135/2136 Å) that is measurable in stars of low metallicity. Using archival Hubble Space Telescope-Space Telescope Imaging Spectrograph spectra, we have measured P abundances in 13 stars spanning -3.3 <= [Fe/H] <= -0.2, and obtained an upper limit for a star with [Fe/H] ~ -3.8. Combined with the only other sample of P abundances in solar-type stars in the literature, which spans a range of -1 <= [Fe/H] <= +0.2, we compare the stellar data to chemical evolution models. Our results support previous indications that massive-star P yields may need to be increased by a factor of a few to match stellar data at all metallicities. Our results also show that hypernovae were important contributors to the P production in the early universe. As P is one of the key building blocks of life, we also discuss the chemical evolution of the important elements to life, C-N-O-P-S, together. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work is supported through program AR-13246. Other portions of this work are based on data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile, and the McDonald Observatory of the University of Texas at Austin.

A field experiment demonstrating plant life-history evolution and its eco-evolutionary feedback to seed predator populations.

PubMed

Agrawal, Anurag A; Johnson, Marc T J; Hastings, Amy P; Maron, John L

2013-05-01

The extent to which evolutionary change occurs in a predictable manner under field conditions and how evolutionary changes feed back to influence ecological dynamics are fundamental, yet unresolved, questions. To address these issues, we established eight replicate populations of native common evening primrose (Oenothera biennis). Each population was planted with 18 genotypes in identical frequency. By tracking genotype frequencies with microsatellite DNA markers over the subsequent three years (up to three generations, ≈5,000 genotyped plants), we show rapid and consistent evolution of two heritable plant life-history traits (shorter life span and later flowering time). This rapid evolution was only partially the result of differential seed production; genotypic variation in seed germination also contributed to the observed evolutionary response. Since evening primrose genotypes exhibited heritable variation for resistance to insect herbivores, which was related to flowering time, we predicted that evolutionary changes in genotype frequencies would feed back to influence populations of a seed predator moth that specializes on O. biennis. By the conclusion of the experiment, variation in the genotypic composition among our eight replicate field populations was highly predictive of moth abundance. These results demonstrate how rapid evolution in field populations of a native plant can influence ecological interactions.

The Evolution of Fertility Expectations over the Life Course

PubMed Central

HAYFORD, SARAH R.

2009-01-01

In low-fertility contexts, how many children people have is largely a product of how many children they want. However, the social, institutional, and individual factors that influence how many children people want are not well understood. In particular, there is scant evidence about how fertility expectations change over the life course. This article provides an empirical description of changes in women’s expected fertility over the entire span of childbearing years. Using data from the National Longitudinal Survey of Youth, 1979 cohort, group-based trajectory analysis illuminates common patterns in the evolution of fertility intentions and identifies individual characteristics associated with these patterns. Factors related to family formation, such as marriage and whether a woman has a child at an early age, are found to be the most consistent correlates of patterns of change in expected family size. PMID:20084828

Life-Span Learning: A Developmental Perspective

ERIC Educational Resources Information Center

Thornton, James E.

2003-01-01

The article discusses learning as embedded processes of development and aging, and as social activity over the life course. The concept of life-span learning is proposed and outlined to discuss these processes as aspects of and propositions in life-span development and aging theory. Life-span learning processes arise and continuously develop in a…

Interpreting the universal phylogenetic tree

NASA Technical Reports Server (NTRS)

Woese, C. R.

2000-01-01

The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist.

Amphibious fishes: evolution and phenotypic plasticity.

PubMed

Wright, Patricia A; Turko, Andy J

2016-08-01

Amphibious fishes spend part of their life in terrestrial habitats. The ability to tolerate life on land has evolved independently many times, with more than 200 extant species of amphibious fishes spanning 17 orders now reported. Many adaptations for life out of water have been described in the literature, and adaptive phenotypic plasticity may play an equally important role in promoting favourable matches between the terrestrial habitat and behavioural, physiological, biochemical and morphological characteristics. Amphibious fishes living at the interface of two very different environments must respond to issues relating to buoyancy/gravity, hydration/desiccation, low/high O2 availability, low/high CO2 accumulation and high/low NH3 solubility each time they traverse the air-water interface. Here, we review the literature for examples of plastic traits associated with the response to each of these challenges. Because there is evidence that phenotypic plasticity can facilitate the evolution of fixed traits in general, we summarize the types of investigations needed to more fully determine whether plasticity in extant amphibious fishes can provide indications of the strategies used during the evolution of terrestriality in tetrapods. © 2016. Published by The Company of Biologists Ltd.

Genetic Drift, Not Life History or RNAi, Determine Long-Term Evolution of Transposable Elements

PubMed Central

Szitenberg, Amir; Cha, Soyeon; Opperman, Charles H.; Bird, David M.; Blaxter, Mark L.; Lunt, David H.

2016-01-01

Abstract Transposable elements (TEs) are a major source of genome variation across the branches of life. Although TEs may play an adaptive role in their host’s genome, they are more often deleterious, and purifying selection is an important factor controlling their genomic loads. In contrast, life history, mating system, GC content, and RNAi pathways have been suggested to account for the disparity of TE loads in different species. Previous studies of fungal, plant, and animal genomes have reported conflicting results regarding the direction in which these genomic features drive TE evolution. Many of these studies have had limited power, however, because they studied taxonomically narrow systems, comparing only a limited number of phylogenetically independent contrasts, and did not address long-term effects on TE evolution. Here, we test the long-term determinants of TE evolution by comparing 42 nematode genomes spanning over 500 million years of diversification. This analysis includes numerous transitions between life history states, and RNAi pathways, and evaluates if these forces are sufficiently persistent to affect the long-term evolution of TE loads in eukaryotic genomes. Although we demonstrate statistical power to detect selection, we find no evidence that variation in these factors influence genomic TE loads across extended periods of time. In contrast, the effects of genetic drift appear to persist and control TE variation among species. We suggest that variation in the tested factors are largely inconsequential to the large differences in TE content observed between genomes, and only by these large-scale comparisons can we distinguish long-term and persistent effects from transient or random changes. PMID:27566762

Mitochondrial Reactive Oxygen Species Trigger Hypoxia-Inducible Factor-Dependent Extension of the Replicative Life Span during Hypoxia▿

PubMed Central

Bell, Eric L.; Klimova, Tatyana A.; Eisenbart, James; Schumacker, Paul T.; Chandel, Navdeep S.

2007-01-01

Physiological hypoxia extends the replicative life span of human cells in culture. Here, we report that hypoxic extension of replicative life span is associated with an increase in mitochondrial reactive oxygen species (ROS) in primary human lung fibroblasts. The generation of mitochondrial ROS is necessary for hypoxic activation of the transcription factor hypoxia-inducible factor (HIF). The hypoxic extension of replicative life span is ablated by a dominant negative HIF. HIF is sufficient to induce telomerase reverse transcriptase mRNA and telomerase activity and to extend replicative life span. Furthermore, the down-regulation of the von Hippel-Lindau tumor suppressor protein by RNA interference increases HIF activity and extends replicative life span under normoxia. These findings provide genetic evidence that hypoxia utilizes mitochondrial ROS as signaling molecules to activate HIF-dependent extension of replicative life span. PMID:17562866

Life-Span Extension by Caloric Restriction Is Determined by Type and Level of Food Reduction and by Reproductive Mode in Brachionus manjavacas (Rotifera)

PubMed Central

2013-01-01

We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%–70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension. PMID:22904096

Life-span extension by caloric restriction is determined by type and level of food reduction and by reproductive mode in Brachionus manjavacas (Rotifera).

PubMed

Gribble, Kristin E; Welch, David B Mark

2013-04-01

We measured life span and fecundity of three reproductive modes in a clone of the monogonont rotifer Brachionus manjavacas subjected to chronic caloric restriction (CCR) over a range of food concentrations or to intermittent fasting (IF). IF increased life span 50%-70% for all three modes, whereas CCR increased life span of asexual females derived from sexually or asexually produced eggs, but not that of sexual females. The main effect of CR on both asexual modes was to delay death at young ages, rather than to prevent death at middle ages or to greatly extend maximum life span; in contrast CR in sexual females greatly increased the life span of a few long-lived individuals. Lifetime fecundity did not decrease with CCR, suggesting a lack of resource allocation trade-off between somatic maintenance and reproduction. Multiple outcomes for a clonal lineage indicate that different responses are established through epigenetic programming, whereas differences in life-span allocations suggest that multiple genetic mechanisms mediate life-span extension.

Life as a Cosmic Phenomenon: 2. the Panspermic Trajectory of Homo Sapiens

NASA Astrophysics Data System (ADS)

Tokoro, Gensuke; Wickramasinghe, N. Chandra

We discuss the origin and evolution of Homo sapiens in a cosmic context, and in relation to the Hoyle-Wickramasinghe theory of panspermia for which there is now overwhelming evidence. It is argued that the first bacteria (archea) incident on the Earth via the agency of comets 3.8-4 billion years ago continued at later times to be augmented by viral genes (DNA, RNA) from space that eventually led to the evolutionary patterns we see in present-day biology. We argue that the current evolutionary status of Homo sapiens as well as its future trajectory is circumscribed by evolutionary processes that were pre-determined on a cosmic scale -- over vast distances and enormous spans of cosmic time. Based on this teleological hypothesis we postulate that two distinct classes of cosmic viruses (cosmic viral genes) are involved in accounting for the facts relating to the evolution of life.

Integrating the pace-of-life syndrome across species, sexes and individuals: covariation of life history and personality under pesticide exposure.

PubMed

Debecker, Sara; Sanmartín-Villar, Iago; de Guinea-Luengo, Miguel; Cordero-Rivera, Adolfo; Stoks, Robby

2016-05-01

The pace-of-life syndrome (POLS) hypothesis integrates covariation of life-history traits along a fast-slow continuum and covariation of behavioural traits along a proactive-reactive personality continuum. Few studies have investigated these predicted life-history/personality associations among species and between sexes. Furthermore, whether and how contaminants interfere with POLS patterns remains unexplored. We tested for covariation patterns in life history and in behaviour, and for life-history/personality covariation among species, among individuals within species and between sexes. Moreover, we investigated whether pesticide exposure affects covariation between life history and behaviour and whether species and sexes with a faster POLS strategy have a higher sensitivity to pesticides. We reared larvae of four species of Ischnura damselflies in a common garden experiment with an insecticide treatment (chlorpyrifos absent/present) in the final instar. We measured four life-history traits (larval growth rate during the pesticide treatment, larval development time, adult mass and life span) and two behavioural traits (larval feeding activity and boldness, each before and after the pesticide treatment). At the individual level, life-history traits and behavioural traits aligned along a fast-slow and a proactive-reactive continuum, respectively. Species-specific differences in life history, with fast-lived species having a faster larval growth and development, a lower mass at emergence and a shorter life span, suggested that time constraints in the larval stage were predictably driving life-history evolution both in the larval stage and across metamorphosis in the adult stage. Across species, females were consistently more slow-lived than males, reflecting that a large body size and a long life span are generally more important for females. In contrast to the POLS hypothesis, there was only little evidence for the expected positive coupling between life-history pace and proactivity. Pesticide exposure decreased larval growth rate and affected life-history/personality covariation in the most fast-lived species. Our study supports the existence of life-history and behavioural continua with limited support for life-history/personality covariation. Variation in digestive physiology may explain this decoupling of life history and behaviour and provide valuable mechanistic insights to understand and predict the occurrence of life-history/personality covariation patterns. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Partial uncoupling of oxidative phosphorylation induces premature senescence in human fibroblasts and yeast mother cells.

PubMed

Stöckl, Petra; Zankl, Christina; Hütter, Eveline; Unterluggauer, Hermann; Laun, Peter; Heeren, Gino; Bogengruber, Edith; Herndler-Brandstetter, Dietmar; Breitenbach, Michael; Jansen-Dürr, Pidder

2007-09-15

The mitochondrial theory of aging predicts that functional alterations in mitochondria leading to reactive oxygen species (ROS) production contribute to the aging process in most if not all species. Using cellular senescence as a model for human aging, we have recently reported partial uncoupling of the respiratory chain in senescent human fibroblasts. In the present communication, we address a potential cause-effect relationship between impaired mitochondrial coupling and premature senescence. Chronic exposure of human fibroblasts to the chemical uncoupler carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) led to a temporary, reversible uncoupling of oxidative phosphorylation. FCCP inhibited cell proliferation in a dose-dependent manner, and a significant proportion of the cells entered premature senescence within 12 days. Unexpectedly, chronic exposure of cells to FCCP led to a significant increase in ROS production, and the inhibitory effect of FCCP on cell proliferation was eliminated by the antioxidant N-acetyl-cysteine. However, antioxidant treatment did not prevent premature senescence, suggesting that a reduction in the level of oxidative phosphorylation contributes to phenotypical changes characteristic of senescent human fibroblasts. To assess whether this mechanism might be conserved in evolution, the influence of mitochondrial uncoupling on replicative life span of yeast cells was also addressed. Similar to our findings in human fibroblasts, partial uncoupling of oxidative phsophorylation in yeast cells led to a substantial decrease in the mother-cell-specific life span and a concomitant incrase in ROS, indicating that life span shortening by mild mitochondrial uncoupling may represent a "public" mechanism of aging.

Comparative transcriptional profiling identifies takeout as a gene that regulates life span

PubMed Central

Bauer, Johannes; Antosh, Michael; Chang, Chengyi; Schorl, Christoph; Kolli, Santharam; Neretti, Nicola; Helfand, Stephen L.

2010-01-01

A major challenge in translating the positive effects of dietary restriction (DR) for the improvement of human health is the development of therapeutic mimics. One approach to finding DR mimics is based upon identification of the proximal effectors of DR life span extension. Whole genome profiling of DR in Drosophila shows a large number of changes in gene expression, making it difficult to establish which changes are involved in life span determination as opposed to other unrelated physiological changes. We used comparative whole genome expression profiling to discover genes whose change in expression is shared between DR and two molecular genetic life span extending interventions related to DR, increased dSir2 and decreased Dmp53 activity. We find twenty-one genes shared among the three related life span extending interventions. One of these genes, takeout, thought to be involved in circadian rhythms, feeding behavior and juvenile hormone binding is also increased in four other life span extending conditions: Rpd3, Indy, chico and methuselah. We demonstrate takeout is involved in longevity determination by specifically increasing adult takeout expression and extending life span. These studies demonstrate the power of comparative whole genome transcriptional profiling for identifying specific downstream elements of the DR life span extending pathway. PMID:20519778

Ancestral telomere shortening: a countdown that will increase mean life span?

PubMed

Hertzog, Radu G

2006-01-01

Like cells, all mammals have a limited life span. Among cells there are a few exceptions (e.g., immortal cells), among mammals not, even if some of them live longer. Many in vitro and in vivo studies support the consensus that telomere length is strongly correlated with life span. At the somatic cellular level, long telomeres have been associated with longer life span. A different situation can be seen in immortal cells, such as cancer, germ and stem cells, where telomeres are maintained by telomerase, a specialized reverse transcriptase that is involved in synthesis of telomeres. Irrespective of telomere length, if telomerase is active, telomeres can be maintained at a sufficient length to ensure cell survival. To the contrary, telomeres shorten progressively with each cell division and when a critical telomere length (Hayflick limit) is reached, the cells undergo senescence and subsequently apoptosis. In mammals, those with the longest telomeres (e.g., mice) have the shortest life span. Furthermore, the shorter the mean telomere length, the longer the mean life span, as observed in humans (10-14 kpb) and bowhead-whales (undetermined telomere length), which have the longest mean life span among mammals. Over the past centuries, human average life span has increased. The hypothesis presented here suggests that this continual increase in the mean life span could be due to a decrease of mean telomere length over the last hundreds years. Actually, the life span is not directly influenced by length of telomeres, but rather by telomere length - dependent gene expression pattern. According to Greider, "rather than average telomere length, it is the shortest telomere length that makes the biggest difference to a cell". In the context of fast-growing global elderly population due to increase in life expectancy, it also seem to be an age related increase in cancer incidence. Nevertheless, extending healthy life span could depend on how good cells achieve, during the prenatal period and few years after birth, the equilibrium between telomere length and telomerase activity, as seen in germ cells. After all, I suggest that decrease in mean telomere length might result in, on the one hand, an increased life span and, on the other, a higher risk of tumorigenesis.

Life in the Universe: Foundation for exciting multidisciplinary science activities for middle and elementary school classes

NASA Technical Reports Server (NTRS)

Milne, D.; O'Sullivan, K.

1994-01-01

Young students find extra-terrestrial life one of the most intriguing of all topics. A project funded by the National Science Foundation and NASA, and administered by the SETI Institute, is underway to devise science lessons for grades 3-9 that draw upon this fascination. The lessons are designed by teachers and persons with long experience at curriculum design, tested in classrooms, revised and retested. Six guides, each containing some 6-10 science lessons, will be finished by summer, 1994.The theme Life in the Universe lends itself naturally to integrated treatment of facts and concepts from many scientific disciplines. The lessons for two completed guides span the origin of planet systems, evolution of complex life, chemical makeup of life, astronomy, spectroscopy, continental drift, mathematics and SETI (Search for Extra-Terrestrial Intelligence). All lessons are hands-on, interesting, and successful.

Life in the universe: foundation for exciting multidisciplinary science activities for middle and elementary school classes.

PubMed

Milne, D; O'Sullivan, K

1994-01-01

Young students find extra-terrestrial life one of the most intriguing of all topics. A project funded by the National Science Foundation and NASA, and administered by the SETI Institute, is underway to devise science lessons for grades 3-9 that draw upon this fascination. The lessons are designed by teachers and persons with long experience at curriculum design, tested in classrooms, revised and retested. Six guides, each containing some 6-10 science lessons, will be finished by summer, 1994. The theme Life in the Universe lends itself naturally to integrated treatment of facts and concepts from many scientific disciplines. The lessons for two completed guides span the origin of planet systems, evolution of complex life, chemical makeup of life, astronomy, spectroscopy, continental drift, mathematics and SETI (Search for Extra-Terrestrial Intelligence). All lessons are hands-on, interesting, and successful.

Baron Kelvin of Largs: an economical engineer.

PubMed

Fara, Patricia

2007-12-01

William Thomson--honoured as Baron Kelvin of Largs--was Victorian Britain's most famous physicist, especially celebrated for laying the trans-Atlantic telegraph cable. As well as profiting financially from his many engineering projects, Kelvin introduced influential theories about energy and electromagnetism, all strongly coloured by his industrial experiences and the thrifty attitudes of Scottish Christians. Never accepting radioactivity as an additional energy source to the sun, he insisted that the Earth's life span was far too short for evolution to have taken place.

Biofilms 2015: Multidisciplinary Approaches Shed Light into Microbial Life on Surfaces

PubMed Central

Yildiz, Fitnat

2016-01-01

The 7th ASM Conference on Biofilms was held in Chicago, Illinois, from 24 to 29 October 2015. The conference provided an international forum for biofilm researchers across academic and industry platforms, and from different scientific disciplines, to present and discuss new findings and ideas. The meeting covered a wide range of topics, spanning environmental sciences, applied biology, evolution, ecology, physiology, and molecular biology of the biofilm lifestyle. This report summarizes the presentations with regard to emerging biofilm-related themes. PMID:26977109

The meaning of death: some simulations of a model of healthy and unhealthy consumption.

PubMed

Forster, M

2001-07-01

Simulations of a model of healthy and unhealthy consumption are used to investigate the impact of various terminal conditions on life-span, pathways of health-related consumption and health. A model in which life-span and the 'death' stock of health are fixed is compared to versions in which (i) the 'death' stock of health is freely chosen; (ii) life-span is freely chosen; (iii) both the 'death' stock of health and life-span are freely chosen. The choice of terminal conditions has a striking impact on optimal plans. Results are discussed with reference to the existing demand for health literature and illustrate the application of iterative processes to determine optimal life-span, the role played by the marginal value of health capital in determining optimal plans, and the importance of checking the second-order conditions for the optimal choice of life-span.

A Motivational Theory of Life-Span Development

PubMed Central

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the action-phase model of developmental regulation with their original life-span theory of control to present a comprehensive theory of development. Third, they reviewed the relevant empirical literature testing key propositions of the Motivational Theory of Life-Span Development. Finally, because the conceptual reach of their theory goes far beyond the current empirical base, they pointed out areas that deserve further and more focused empirical inquiry. PMID:20063963

Longevity and age-related lesions in a laboratory colony of grasshopper mice, Onychomys leucogaster

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Farrell, T.P.; Cosgrove, G.E.

1975-07-01

Mated pairs of northern grasshopper mice, Onychomys leucogaster fuscogriseus, were maintained in a laboratory colony to determine their median longevity, maximum life span, and age-related pathologies. Median life span for both sexes and four cohorts was 1411 days and the maximum life span was 1915 days. There were no significant differences between sexes, but cohorts 5-7 generations removed from wild-caught parents had shorter median life spans. (auth)

Increased iron supplied through Fet3p results in replicative life span extension of Saccharomyces cerevisiae under conditions requiring respiratory metabolism.

PubMed

Botta, Gabriela; Turn, Christina S; Quintyne, Nicholas J; Kirchman, Paul A

2011-10-01

We have previously shown that copper supplementation extends the replicative life span of Saccharomyces cerevisiae when grown under conditions forcing cells to respire. We now show that copper's effect on life span is through Fet3p, a copper containing enzyme responsible for high affinity transport of iron into yeast cells. Life span extensions can also be obtained by supplementing the growth medium with 1mM ferric chloride. Extension by high iron levels is still dependent on the presence of Fet3p. Life span extension by iron or copper requires growth on media containing glycerol as the sole carbon source, which forces yeast to respire. Yeast grown on glucose containing media supplemented with iron show no extension of life span. The iron associated with cells grown in media supplemented with copper or iron is 1.4-1.8 times that of cells grown without copper or iron supplementation. As with copper supplementation, iron supplementation partially rescues the life span of superoxide dismutase mutants. Cells grown with copper supplementation display decreased production of superoxide as measured by dihydroethidium staining. Copyright © 2011 Elsevier Inc. All rights reserved.

Evaluative ratings and attention across the life span: emotional arousal and gender.

PubMed

Ferrari, Vera; Bruno, Nicola; Chattat, Rabih; Codispoti, Maurizio

2017-04-01

This study was designed to investigate the evolution of emotional processing over the whole adult life span as a function of stimulus arousal and participants' gender. To this end, self-reported affective evaluation and attentional capture prompted by pleasant and unpleasant pictures varying in arousal were measured in a large sample of participants (n = 211) balanced by gender and equally spread across seven decades from 20 to 90 years. Results showed age differences only for affective evaluation of pleasant stimuli, with opposite patterns depending on stimulus arousal. As age increased, low-arousing pleasant cues (e.g. images of babies) were experienced as more pleasant and arousing by both males and females, whereas high-arousing stimuli (e.g. erotic images) were experienced as less pleasant only by females. In contrast, emotional pictures (both pleasant and unpleasant) were effective at capturing attention in a similar way across participants, regardless of age and gender. Taken together, these findings suggest that specific emotional cues prompt different subjective responses across different age groups, while basic mechanisms involved in attentional engagement towards both pleasant and unpleasant stimuli are preserved in healthy ageing.

How long will my mouse live? Machine learning approaches for prediction of mouse life span.

PubMed

Swindell, William R; Harper, James M; Miller, Richard A

2008-09-01

Prediction of individual life span based on characteristics evaluated at middle-age represents a challenging objective for aging research. In this study, we used machine learning algorithms to construct models that predict life span in a stock of genetically heterogeneous mice. Life-span prediction accuracy of 22 algorithms was evaluated using a cross-validation approach, in which models were trained and tested with distinct subsets of data. Using a combination of body weight and T-cell subset measures evaluated before 2 years of age, we show that the life-span quartile to which an individual mouse belongs can be predicted with an accuracy of 35.3% (+/-0.10%). This result provides a new benchmark for the development of life-span-predictive models, but improvement can be expected through identification of new predictor variables and development of computational approaches. Future work in this direction can provide tools for aging research and will shed light on associations between phenotypic traits and longevity.

The fundamental units, processes and patterns of evolution, and the Tree of Life conundrum

PubMed Central

Koonin, Eugene V; Wolf, Yuri I

2009-01-01

Background The elucidation of the dominant role of horizontal gene transfer (HGT) in the evolution of prokaryotes led to a severe crisis of the Tree of Life (TOL) concept and intense debates on this subject. Concept Prompted by the crisis of the TOL, we attempt to define the primary units and the fundamental patterns and processes of evolution. We posit that replication of the genetic material is the singular fundamental biological process and that replication with an error rate below a certain threshold both enables and necessitates evolution by drift and selection. Starting from this proposition, we outline a general concept of evolution that consists of three major precepts. 1. The primary agency of evolution consists of Fundamental Units of Evolution (FUEs), that is, units of genetic material that possess a substantial degree of evolutionary independence. The FUEs include both bona fide selfish elements such as viruses, viroids, transposons, and plasmids, which encode some of the information required for their own replication, and regular genes that possess quasi-independence owing to their distinct selective value that provides for their transfer between ensembles of FUEs (genomes) and preferential replication along with the rest of the recipient genome. 2. The history of replication of a genetic element without recombination is isomorphously represented by a directed tree graph (an arborescence, in the graph theory language). Recombination within a FUE is common between very closely related sequences where homologous recombination is feasible but becomes negligible for longer evolutionary distances. In contrast, shuffling of FUEs occurs at all evolutionary distances. Thus, a tree is a natural representation of the evolution of an individual FUE on the macro scale, but not of an ensemble of FUEs such as a genome. 3. The history of life is properly represented by the "forest" of evolutionary trees for individual FUEs (Forest of Life, or FOL). Search for trends and patterns in the FOL is a productive direction of study that leads to the delineation of ensembles of FUEs that evolve coherently for a certain time span owing to a shared history of vertical inheritance or horizontal gene transfer; these ensembles are commonly known as genomes, taxa, or clades, depending on the level of analysis. A small set of genes (the universal genetic core of life) might show a (mostly) coherent evolutionary trend that transcends the entire history of cellular life forms. However, it might not be useful to denote this trend "the tree of life", or organismal, or species tree because neither organisms nor species are fundamental units of life. Conclusion A logical analysis of the units and processes of biological evolution suggests that the natural fundamental unit of evolution is a FUE, that is, a genetic element with an independent evolutionary history. Evolution of a FUE on the macro scale is naturally represented by a tree. Only the full compendium of trees for individual FUEs (the FOL) is an adequate depiction of the evolution of life. Coherent evolution of FUEs over extended evolutionary intervals is a crucial aspect of the history of life but a "species" or "organismal" tree is not a fundamental concept. Reviewers This articles was reviewed by Valerian Dolja, W. Ford Doolittle, Nicholas Galtier, and William Martin PMID:19788730

Evolution of the antigen-specific CD8+ TCR repertoire across the life span: evidence for clonal homogenization of the old TCR repertoire.

PubMed

Rudd, Brian D; Venturi, Vanessa; Davenport, Miles P; Nikolich-Zugich, Janko

2011-02-15

Defects in T cell responses against pathogens and reduced diversity of TCRs have been described at both extremes of the life span. Yet, we still lack information on how Ag-specific T cell populations are maintained and/or altered from birth to old age. In this study, for the first time to our knowledge, we provide insight into Ag-specific TCR repertoire changes over the life span at the single-cell level. We have examined the TCR diversity of the primary CD8(+) T cell response to the immunodominant HSV-1 epitope HSV glycoprotein B 495-502 (HSV gB(498-505); SSIEFARL) (gB-8p) in neonatal, adult, and old C57BL/6 mice. The global distinctive features of the gB-8p-specific TCR repertoire were preserved in mice of different ages. However, both old and especially neonatal mice exhibited significant decreases in TCR diversity compared with that of adult mice. Still, although the neonatal Ag-specific repertoire comprised expectedly shorter germline-biased CDR3β lengths, the repertoire was surprisingly complex, and only a minority of responding cells lacked random nucleotide additions. Changes with aging included increased use of the already dominant TCRVβ10 family, a trend for lower content of the TCR containing the germline WG motif in the CDR3, and a remarkable sharing of one dominant clonotype between individual old mice, implying operation of selective mechanisms. Implications for the rational design of vaccines for neonates and the elderly are discussed.

Exploratory and problem-solving consumer behavior across the life span.

PubMed

Lesser, J A; Kunkel, S R

1991-09-01

Different cognitive functioning, social, and personality changes appear to occur systematically during the adult life span. This article synthesizes research on life span changes in order to develop age-specific models of shopping behavior. The models are tested within a naturalistic field study of shoppers.

Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring

PubMed Central

Gribble, Kristin E; Jarvis, George; Bock, Martha; Mark Welch, David B

2014-01-01

While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span. PMID:24661622

Genomic evidence for large, long-lived ancestors to placental mammals.

PubMed

Romiguier, J; Ranwez, V; Douzery, E J P; Galtier, N

2013-01-01

It is widely assumed that our mammalian ancestors, which lived in the Cretaceous era, were tiny animals that survived massive asteroid impacts in shelters and evolved into modern forms after dinosaurs went extinct, 65 Ma. The small size of most Mesozoic mammalian fossils essentially supports this view. Paleontology, however, is not conclusive regarding the ancestry of extant mammals, because Cretaceous and Paleocene fossils are not easily linked to modern lineages. Here, we use full-genome data to estimate the longevity and body mass of early placental mammals. Analyzing 36 fully sequenced mammalian genomes, we reconstruct two aspects of the ancestral genome dynamics, namely GC-content evolution and nonsynonymous over synonymous rate ratio. Linking these molecular evolutionary processes to life-history traits in modern species, we estimate that early placental mammals had a life span above 25 years and a body mass above 1 kg. This is similar to current primates, cetartiodactyls, or carnivores, but markedly different from mice or shrews, challenging the dominant view about mammalian origin and evolution. Our results imply that long-lived mammals existed in the Cretaceous era and were the most successful in evolution, opening new perspectives about the conditions for survival to the Cretaceous-Tertiary crisis.

Developmental Regulation across the Life Span: Toward a New Synthesis

ERIC Educational Resources Information Center

Haase, Claudia M.; Heckhausen, Jutta; Wrosch, Carsten

2013-01-01

How can individuals regulate their own development to live happy, healthy, and productive lives? Major theories of developmental regulation across the life span have been proposed (e.g., dual-process model of assimilation and accommodation; motivational theory of life-span development; model of selection, optimization, and compensation), but they…

A Motivational Theory of Life-Span Development

ERIC Educational Resources Information Center

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

This article had four goals. First, the authors identified a set of general challenges and questions that a life-span theory of development should address. Second, they presented a comprehensive account of their Motivational Theory of Life-Span Development. They integrated the model of optimization in primary and secondary control and the…

Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

DOEpatents

Stampfer, Martha R.; Garbe, James C.

2016-06-28

Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

DOEpatents

Stampfer, Martha R; Garbe, James C

2015-02-24

Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

Lifelong alpha-tocopherol supplementation increases the median life span of C57BL/6 mice in the cold but has only minor effects on oxidative damage.

PubMed

Selman, Colin; McLaren, Jane S; Mayer, Claus; Duncan, Jackie S; Collins, Andrew R; Duthie, Garry G; Redman, Paula; Speakman, John R

2008-02-01

The effects of dietary antioxidant supplementation on oxidative stress and life span are confused. We maintained C57BL/6 mice at 7 +/- 2 degrees C and supplemented their diet with alpha-tocopherol from 4 months of age. Supplementation significantly increased (p = 0.042) median life span by 15% (785 days, n = 44) relative to unsupplemented controls (682 days, n = 43) and also increased maximum life span (oldest 10%, p = 0.028). No sex or sex by treatment interaction effects were observed on life span, with treatment having no effect on resting or daily metabolic rate. Lymphocyte and hepatocyte oxidative DNA damage and hepatic lipid peroxidation were unaffected by supplementation, but hepatic oxidative DNA damage increased with age. Using a cDNA macroarray, genes associated with xenobiotic metabolism were significantly upregulated in the livers of female mice at 6 months of age (2 months supplementation). At 22 months of age (18 months supplementation) this response had largely abated, but various genes linked to the p21 signaling pathway were upregulated at this time. We suggest that alpha-tocopherol may initially be metabolized as a xenobiotic, potentially explaining why previous studies observe a life span extension generally when lifelong supplementation is initiated early in life. The absence of any significant effect on oxidative damage suggests that the life span extension observed was not mediated via any antioxidant properties of alpha-tocopherol. We propose that the life span extension observed following alpha-tocopherol supplementation may be mediated via upregulation of cytochrome p450 genes after 2 months of supplementation and/or upregulation of p21 signaling genes after 18 months of supplementation. However, these signaling pathways now require further investigation to establish their exact role in life span extension following alpha-tocopherol supplementation.

Blade life span, structural investment, and nutrient allocation in giant kelp.

PubMed

Rodriguez, Gabriel E; Reed, Daniel C; Holbrook, Sally J

2016-10-01

The turnover of plant biomass largely determines the amount of energy flowing through an ecosystem and understanding the processes that regulate turnover has been of interest to ecologists for decades. Leaf life span theory has proven useful in explaining patterns of leaf turnover in relation to resource availability, but the predictions of this theory have not been tested for macroalgae. We measured blade life span, size, thickness, nitrogen content, pigment content, and maximum photosynthetic rate (P max) in the giant kelp (Macrocystis pyrifera) along a strong resource (light) gradient to test whether the predictions of leaf life span theory applied to this alga. We found that shorter blade life spans and larger blade areas were associated with increased light availability. In addition, nitrogen and P max decreased with blade age, and their decrease was greater in shorter lived blades. These observations are generally consistent with patterns observed for higher plants and the prevailing theory of leaf life span. By contrast, variation observed in pigments of giant kelp was inconsistent with that predicted by leaf life span theory, as blades growing in the most heavily shaded portion of the forest had the lowest chlorophyll content. This result may reflect the dual role of macroalgal blades in carbon fixation and nutrient absorption and the ability of giant kelp to modify blade physiology to optimize the acquisition of light and nutrients. Thus, the marine environment may place demands on resource acquisition and allocation that have not been previously considered with respect to leaf life span optimization.

78. VIEW SHOWING PLACEMENT OF LIFE SPAN SHOE ON PIER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

78. VIEW SHOWING PLACEMENT OF LIFE SPAN SHOE ON PIER 6, LOOKING NORTH, March 5, 1935 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

Learning From Leaders: Life-span Trends in Olympians and Supercentenarians

PubMed Central

Berthelot, Geoffroy; Marck, Adrien; Noirez, Philippe; Latouche, Aurélien; Toussaint, Jean-François

2015-01-01

Life-span trends progression has worldwide practical implications as it may affect the sustainability of modern societies. We aimed to describe the secular life-span trends of populations with a propensity to live longer—Olympians and supercentenarians—under two hypotheses: an ongoing life-span extension versus a biologic “probabilistic barrier” limiting further progression. In a study of life-span densities (total number of life durations per birth date), we analyzed 19,012 Olympians and 1,205 supercentenarians deceased between 1900 and 2013. Among most Olympians, we observed a trend toward increased life duration. This trend, however, decelerates at advanced ages leveling off with the upper values with a perennial gap between Olympians and supercentenarians during the whole observation period. Similar tendencies are observed among supercentenarians, and over the last years, a plateau attests to a stable longevity pattern among the longest-lived humans. The common trends between Olympians and supercentenarians indicate similar mortality pressures over both populations that increase with age, scenario better explained by a biologic “barrier” forecast. PMID:25143003

What Prolongs a Butterfly's Life?: Trade-Offs between Dormancy, Fecundity and Body Size

PubMed Central

Haeler, Elena; Fiedler, Konrad; Grill, Andrea

2014-01-01

In butterflies, life span often increases only at the expense of fecundity. Prolonged life span, on the other hand, provides more opportunities for oviposition. Here, we studied the association between life span and summer dormancy in two closely related species of Palearctic Meadow Brown butterflies, the endemic Maniola nurag and the widespread M. jurtina, from two climatic provenances, a Mediterranean and a Central European site, and tested the relationships between longevity, body size and fecundity. We experimentally induced summer dormancy and hence prolonged the butterflies’ life in order to study the effects of such a prolonged life. We were able to modulate longevity only in Mediterranean females by rearing them under summer photoperiodic conditions (light 16 h : dark 8 h), thereby more than doubling their natural life span, to up to 246 days. Central European individuals kept their natural average live span under all treatments, as did Mediterranean individuals under autumn treatment (light 11: dark 13). Body size only had a significant effect in the smaller species, M. nurag, where it affected the duration of dormancy and lifetime fecundity. In the larger species, M. jurtina, a prolonged adult life span did, surprisingly, not convey any fecundity loss. In M. nurag, which generally deposited fewer eggs, extended life had a fecundity cost. We conclude that Mediterranen M. jurtina butterflies have an extraordinary plasticity in aging which allows them to extend life span in response to adverse environmental conditions and relieve the time limitation on egg-laying while maintaining egg production at equal levels. PMID:25390334

Teaching the Psychology of Aging: A Life-Span Perspective.

ERIC Educational Resources Information Center

Seltzer, Mildred M.

There is a vast body of literature devoted to an examination of life-span development. Several authors have described the characteristics of the life-span approach and have distinguished it from more traditional forms of psychology. Emphasis has been placed on the multidirectional and multidimensional nature of development and change, as well as…

Qualitative Exploration of Acculturation and Life-Span Issues of Elderly Asian Americans

ERIC Educational Resources Information Center

Lee, Jee Hyang; Heo, Nanseol; Lu, Junfei; Portman, Tarrell Awe Agahe

2013-01-01

Awareness of aging issues across diverse populations begins the journey toward counselors becoming culturally competent across client life spans. Understanding the life-span experiences of cultural groups is important for helping professionals. The purpose of this research was to gain insight into the qualitative experiences of Asian American…

Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring.

PubMed

Gribble, Kristin E; Jarvis, George; Bock, Martha; Mark Welch, David B

2014-08-01

While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

A Review of Ideas Concerning Life Origin

NASA Astrophysics Data System (ADS)

Gindilis, L. M.

2014-10-01

Since the times of Antiquity the and for a long time the idea of self-origination of life was the dominant one. It reappeared again after microorganisms were discovered (XVII century). The possibility of abiogenesis at microbial level was discussed for more than a century. Pateur demonstrated that spontaneous origination of microorganisms in sterile broth was due to those same microorganisms transported by dust particles. Thus proving that every form of life originates from the parental life form. So the question arises: how did the first microorganisms appear on the Earth. There are three possible versions: 1) accidental origination of a viable form; 2) primal organisms were transported to the Earth from outer space; 3) they were formed on the Earth in the process of prebiotic chemical evolution. We discuss the problems of prebiotic evolution from simple monomers up to living cells. An important item of nowadays conceptions of life origination is the hypothesis of the ancient world of RNA as possible precursor of life on Earth. The discovery in carbonaceous chondrites of traces of bacterial life evidences the existence of life in the Solar System even before the formation of the Earth. The idea of life as brought to the Earth out of Cosmos originated under the impression of self-origination hypothesis downfall. It went through several stages (Helmholtz, W. Thompson, XIX century; Arrhenius, early XX century; Hoyle and Wickramasinghe, second half of XX century) and presently evokes constantly growing interest. The panspermia theory does not solve the problem of origination of life, only moves it onto other planets. According to V.A. Mazur, the probability of accidental formation of RNA molecule is negligible not only on the Earth, but in the whole Universe over all the time span of its existence. But it is practically equal to unit in the domain formed at the inflation stage of the evolution of the Universe. A.D.Panov considered panspermia in the Galaxy at the level of prebiotic evolution products. The quantitative model he has brought forward increases life origination probability by many orders of magnitude in comparison with any isolated planet. In this model the life to originates simultaneously on all the planets with proper conditions on the same molecular basis, one and the same genetic code and the same chirality.

Defining wild-type life span in Caenorhabditis elegans.

PubMed

Gems, D; Riddle, D L

2000-05-01

The nematode Caenorhabditis elegans reproduces predominantly as a self-fertilizing hermaphrodite, and this drives laboratory populations to be homozygous at all genetic loci. Passaging of stocks can lead to fixation of spontaneous mutations, especially when the latter do not result in a selective disadvantage under laboratory conditions. Life span may be such a trait, since a comparison of six wild-type N2 lines derived from a common ancestor (but maintained separately in several laboratories) revealed four variants with median adult life spans ranging from 12.0 +/- 0.8 to 17.0 +/- 0.6 days at 20 degrees C. Fertility was also reduced in the two shortest-lived strains. We determined which life span most closely corresponds to that of the authentic wild type by two means. Firstly, N2 hermaphrodites were compared with seven C. elegans wild isolates. The latter were found to resemble only the longest-lived N2 strain. Comparison of male life spans of six lines also revealed additional strain variation. Secondly, life spans of F1 progeny issuing from crosses between N2 variants showed that short life spans were recessive, indicating that they result from loss-of-function mutations. We infer that the longest-lived N2 variant best resembles the original N2 isolate. This is the N2 male stock currently distributed by the Caenorhabditis Genetics Center.

Health Span-Extending Activity of Human Amniotic Membrane- and Adipose Tissue-Derived Stem Cells in F344 Rats

PubMed Central

Kim, Dajeong; Kyung, Jangbeen; Park, Dongsun; Choi, Ehn-Kyoung; Kim, Kwang Sei; Shin, Kyungha; Lee, Hangyoung; Shin, Il Seob; Kang, Sung Keun

2015-01-01

Aging brings about the progressive decline in cognitive function and physical activity, along with losses of stem cell population and function. Although transplantation of muscle-derived stem/progenitor cells extended the health span and life span of progeria mice, such effects in normal animals were not confirmed. Human amniotic membrane-derived mesenchymal stem cells (AMMSCs) or adipose tissue-derived mesenchymal stem cells (ADMSCs) (1 × 106 cells per rat) were intravenously transplanted to 10-month-old male F344 rats once a month throughout their lives. Transplantation of AMMSCs and ADMSCs improved cognitive and physical functions of naturally aging rats, extending life span by 23.4% and 31.3%, respectively. The stem cell therapy increased the concentration of acetylcholine and recovered neurotrophic factors in the brain and muscles, leading to restoration of microtubule-associated protein 2, cholinergic and dopaminergic nervous systems, microvessels, muscle mass, and antioxidative capacity. The results indicate that repeated transplantation of AMMSCs and ADMSCs elongate both health span and life span, which could be a starting point for antiaging or rejuvenation effects of allogeneic or autologous stem cells with minimum immune rejection. Significance This study demonstrates that repeated treatment with stem cells in normal animals has antiaging potential, extending health span and life span. Because antiaging and prolonged life span are issues currently of interest, these results are significant for readers and investigators. PMID:26315571

The Rate of Source Memory Decline across the Adult Life Span

ERIC Educational Resources Information Center

Cansino, Selene; Estrada-Manilla, Cinthya; Hernandez-Ramos, Evelia; Martinez-Galindo, Joyce Graciela; Torres-Trejo, Frine; Gomez-Fernandez, Tania; Ayala-Hernandez, Mariana; Osorio, David; Cedillo-Tinoco, Melisa; Garces-Flores, Lissete; Gomez-Melgarejo, Sandra; Beltran-Palacios, Karla; Guadalupe Garcia-Lazaro, Haydee; Garcia-Gutierrez, Fabiola; Cadena-Arenas, Yadira; Fernandez-Apan, Luisa; Bartschi, Andrea; Resendiz-Vera, Julieta; Rodriguez-Ortiz, Maria Dolores

2013-01-01

Previous studies have suggested that the ability to remember contextual information related to specific episodic experiences declines with advancing age; however, the exact moment in the adult life span when this deficit begins is still controversial. Source memory for spatial information was tested in a life span sample of 1,500 adults between…

Reduced Neuronal Transcription of Escargot, the Drosophila Gene Encoding a Snail-Type Transcription Factor, Promotes Longevity

PubMed Central

Symonenko, Alexander V.; Roshina, Natalia V.; Krementsova, Anna V.; Pasyukova, Elena G.

2018-01-01

In recent years, several genes involved in complex neuron specification networks have been shown to control life span. However, information on these genes is scattered, and studies to discover new neuronal genes and gene cascades contributing to life span control are needed, especially because of the recognized role of the nervous system in governing homeostasis, aging, and longevity. Previously, we demonstrated that several genes that encode RNA polymerase II transcription factors and that are involved in the development of the nervous system affect life span in Drosophila melanogaster. Among other genes, escargot (esg) was demonstrated to be causally associated with an increase in the life span of male flies. Here, we present new data on the role of esg in life span control. We show that esg affects the life spans of both mated and unmated males and females to varying degrees. By analyzing the survival and locomotion of the esg mutants, we demonstrate that esg is involved in the control of aging. We show that increased longevity is caused by decreased esg transcription. In particular, we demonstrate that esg knockdown in the nervous system increased life span, directly establishing the involvement of the neuronal esg function in life span control. Our data invite attention to the mechanisms regulating the esg transcription rate, which is changed by insertions of DNA fragments of different sizes downstream of the structural part of the gene, indicating the direction of further research. Our data agree with the previously made suggestion that alterations in gene expression during development might affect adult lifespan, due to epigenetic patterns inherited in cell lineages or predetermined during the development of the structural and functional properties of the nervous system. PMID:29760717

Herbal Supplement Extends Life Span Under Some Environmental Conditions and Boosts Stress Resistance

PubMed Central

Villeponteau, Bryant; Matsagas, Kennedy; Nobles, Amber C.; Rizza, Cristina; Horwitz, Marc; Benford, Gregory; Mockett, Robin J.

2015-01-01

Genetic studies indicate that aging is modulated by a great number of genetic pathways. We have used Drosophila longevity and stress assays to test a multipath intervention strategy. To carry out this strategy, we supplemented the flies with herbal extracts (SC100) that are predicted to modulate the expression of many genes involved in aging and stress resistance, such as mTOR, NOS, NF-KappaB, and VEGF. When flies were housed in large cages with SC100 added, daily mortality rates of both male and female flies were greatly diminished in mid to late life. Surprisingly, SC100 also stabilized midlife mortality rate increases so as to extend the maximum life span substantially beyond the limits previously reported for D. melanogaster. Under these conditions, SC100 also promoted robust resistance to partial starvation stress and to heat stress. Fertility was the same initially in both treated and control flies, but it became significantly higher in treated flies at older ages as the fertility of control flies declined. Mean and maximum life spans of flies in vials at the same test site were also extended by SC100, but the life spans were short in absolute terms. In contrast, at an independent test site where stress was minimized, the flies exhibited much longer mean life spans, but the survival curves became highly rectangular and the effects of SC100 on both mean and maximum life spans declined greatly or were abolished. The data indicate that SC100 is a novel herbal mix with striking effects on enhancing Drosophila stress resistance and life span in some environments, while minimizing mid to late life mortality rates. They also show that the environment and other factors can have transformative effects on both the length and distribution of survivorship, and on the ability of SC100 to extend the life span. PMID:25879540

Learning From Leaders: Life-span Trends in Olympians and Supercentenarians.

PubMed

Antero-Jacquemin, Juliana da Silva; Berthelot, Geoffroy; Marck, Adrien; Noirez, Philippe; Latouche, Aurélien; Toussaint, Jean-François

2015-08-01

Life-span trends progression has worldwide practical implications as it may affect the sustainability of modern societies. We aimed to describe the secular life-span trends of populations with a propensity to live longer-Olympians and supercentenarians-under two hypotheses: an ongoing life-span extension versus a biologic "probabilistic barrier" limiting further progression. In a study of life-span densities (total number of life durations per birth date), we analyzed 19,012 Olympians and 1,205 supercentenarians deceased between 1900 and 2013. Among most Olympians, we observed a trend toward increased life duration. This trend, however, decelerates at advanced ages leveling off with the upper values with a perennial gap between Olympians and supercentenarians during the whole observation period. Similar tendencies are observed among supercentenarians, and over the last years, a plateau attests to a stable longevity pattern among the longest-lived humans. The common trends between Olympians and supercentenarians indicate similar mortality pressures over both populations that increase with age, scenario better explained by a biologic "barrier" forecast. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America.

The cost of the muse: poets die young.

PubMed

Kaufman, James C

2003-11-01

Although several investigations have found that poets tend to die younger than other types of writers, these studies often do not take into account variables of gender and culture. This study examines 1,987 deceased writers from four different cultures: American, Chinese, Turkish, and Eastern European. Both male and female poets had the shortest life spans of all four types of writers (fiction writers, poets, playwrights, and non-fiction writers), and poets had the shortest life spans in three of the four cultures (and the second shortest life span among Eastern European writers). Possible reasons for the poet's shorter life span are then discussed.

Individual differences in personality change across the adult life span.

PubMed

Schwaba, Ted; Bleidorn, Wiebke

2018-06-01

A precise and comprehensive description of personality continuity and change across the life span is the bedrock upon which theories of personality development are built. Little research has quantified the degree to which individuals deviate from mean-level developmental trends. In this study, we addressed this gap by examining individual differences in personality trait change across the life span. Data came from a nationally representative sample of 9,636 Dutch participants who provided Big Five self-reports at five assessment waves across 7 years. We divided our sample into 14 age groups (ages 16-84 at initial measurement) and estimated latent growth curve models to describe individual differences in personality change across the study period for each trait and age group. Across the adult life span, individual differences in personality change were small but significant until old age. For Openness, Conscientiousness, Extraversion, and Agreeableness, individual differences in change were most pronounced in emerging adulthood and decreased throughout midlife and old age. For Emotional Stability, individual differences in change were relatively consistent across the life span. These results inform theories of life span development and provide future directions for research on the causes and conditions of personality change. © 2017 Wiley Periodicals, Inc.

Effect of Ala-Glu-Asp-Gly peptide on life span and development of spontaneous tumors in female rats exposed to different illumination regimes.

PubMed

Vinogradova, I A; Bukalev, A V; Zabezhinski, M A; Semenchenko, A V; Khavinson, V Kh; Anisimov, V N

2007-12-01

The effects of Ala-Glu-Asp-Gly peptide (Epithalon) on the life span and development of spontaneous tumors were studied in female rats exposed to standard, natural for North-Western Russia, and constant illumination. The mean life span of animals exposed to constant or natural illumination decreased by 13.5 and 25.5%, the maximum by 9 and 7 months, respectively, and spontaneous tumors developed much more rapidly than in animals living under conditions of the standard light regimen. Epithalon (0.1 microg daily 5 times a week from the age of 4 months) did not change the life span of rats living under conditions of standard day/night regimen, while in rats exposed to the natural and constant light it promoted prolongation of the maximum life span by 95 and 24 days, respectively. Epithalon prolonged the mean life span of the last 10% of rats exposed to natural and constant illumination, treated with Epithalon, by 137 and 43 days, respectively. This peptide exhibited virtually no effect on the development of spontaneous tumors in rats exposed to standard and constant illumination, but significantly inhibited their development in rats exposed to natural light.

Genetics and pharmacology of longevity: the road to therapeutics for healthy aging.

PubMed

Castillo-Quan, Jorge Iván; Kinghorn, Kerri J; Bjedov, Ivana

2015-01-01

Aging can be defined as the progressive decline in tissue and organismal function and the ability to respond to stress that occurs in association with homeostatic failure and the accumulation of molecular damage. Aging is the biggest risk factor for human disease and results in a wide range of aging pathologies. Although we do not completely understand the underlying molecular basis that drives the aging process, we have gained exceptional insights into the plasticity of life span and healthspan from the use of model organisms such as the worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Single-gene mutations in key cellular pathways that regulate environmental sensing, and the response to stress, have been identified that prolong life span across evolution from yeast to mammals. These genetic manipulations also correlate with a delay in the onset of tissue and organismal dysfunction. While the molecular genetics of aging will remain a prosperous and attractive area of research in biogerontology, we are moving towards an era defined by the search for therapeutic drugs that promote healthy aging. Translational biogerontology will require incorporation of both therapeutic and pharmacological concepts. The use of model organisms will remain central to the quest for drug discovery, but as we uncover molecular processes regulated by repurposed drugs and polypharmacy, studies of pharmacodynamics and pharmacokinetics, drug-drug interactions, drug toxicity, and therapeutic index will slowly become more prevalent in aging research. As we move from genetics to pharmacology and therapeutics, studies will not only require demonstration of life span extension and an underlying molecular mechanism, but also the translational relevance for human health and disease prevention. Copyright © 2015 Elsevier Inc. All rights reserved.

Grandmothering and cognitive resources are required for the emergence of menopause and extensive post-reproductive lifespan.

PubMed

Aimé, Carla; André, Jean-Baptiste; Raymond, Michel

2017-07-01

Menopause, the permanent cessation of ovulation, occurs in humans well before the end of the expected lifespan, leading to an extensive post-reproductive period which remains a puzzle for evolutionary biologists. All human populations display this particularity; thus, it is difficult to empirically evaluate the conditions for its emergence. In this study, we used artificial neural networks to model the emergence and evolution of allocation decisions related to reproduction in simulated populations. When allocation decisions were allowed to freely evolve, both menopause and extensive post-reproductive life-span emerged under some ecological conditions. This result allowed us to test various hypotheses about the required conditions for the emergence of menopause and extensive post-reproductive life-span. Our findings did not support the Maternal Hypothesis (menopause has evolved to avoid the risk of dying in childbirth, which is higher in older women). In contrast, results supported a shared prediction from the Grandmother Hypothesis and the Embodied Capital Model. Indeed, we found that extensive post-reproductive lifespan allows resource reallocation to increase fertility of the children and survival of the grandchildren. Furthermore, neural capital development and the skill intensiveness of the foraging niche, rather than strength, played a major role in shaping the age profile of somatic and cognitive senescence in our simulated populations. This result supports the Embodied Capital Model rather than the Grand-Mother Hypothesis. Finally, in simulated populations where menopause had already evolved, we found that reduced post-reproductive lifespan lead to reduced children's fertility and grandchildren's survival. The results are discussed in the context of the evolutionary emergence of menopause and extensive post-reproductive life-span.

Divergent patterns of age-dependence in ornamental and reproductive traits in the collared flycatcher.

PubMed

Evans, Simon R; Gustafsson, Lars; Sheldon, Ben C

2011-06-01

Sexual ornaments are predicted to honestly signal individual condition. We might therefore expect ornament expression to show a senescent decline, in parallel with late-life deterioration of other characters. Conversely, life-history theory predicts the reduced residual reproductive value of older individuals will favor increased investment in sexually attractive traits. Using a 25-year dataset of more than 5000 records of breeding collared flycatchers (Ficedula albicollis) of known age, we quantify cross-sectional patterns of age-dependence in ornamental plumage traits and report long-term declines in expression that mask highly significant positive age-dependency. We partition this population-level age-dependency into its between- and within-individual components and show expression of ornamental white plumage patches exhibits within-individual increases with age in both sexes, consistent with life-history theory. For males, ornament expression also covaries with life span, such that, within a cohort, ornamentation indicates survival. Finally, we compared longitudinal age-dependency of reproductive traits and ornamental traits in both sexes, to assess whether these two trait types exhibit similar age-dependency. These analyses revealed contrasting patterns: reproductive traits showed within-individual declines in late-life females consistent with senescence; ornamental traits showed the opposite pattern in both males and females. Hence, our results for both sexes suggest that age-dependent ornament expression is consistent with life-history models of optimal signaling and, unlike reproductive traits, proof against senescence. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Cranberry interacts with dietary macronutrients to promote healthy aging in Drosophila.

PubMed

Wang, Cecilia; Yolitz, Jason; Alberico, Thomas; Laslo, Mara; Sun, Yaning; Wheeler, Charles T; Sun, Xiaoping; Zou, Sige

2014-08-01

Botanicals possess numerous bioactivities, and some promote healthy aging. Dietary macronutrients are major determinants of life span. The interaction between botanicals and macronutrients that modulates life span is not well understood. Here, we investigated the effect of a cranberry-containing botanical on life span and the influence of macronutrients on the longevity-related effect of cranberry in Drosophila. Flies were supplemented with cranberry on three dietary conditions: standard, high sugar-low protein, and low sugar-high protein diets. We found that cranberry slightly extended life span in males fed with the low sugar-high protein diet but not with other diets. Cranberry extended life span in females fed with the standard diet and more prominently the high sugar-low protein diet but not with the low sugar-high protein diet. Life-span extension was associated with increased reproduction and higher expression of oxidative stress and heat shock response genes. Moreover, cranberry improved survival of sod1 knockdown and dfoxo mutant flies but did not increase wild-type fly's resistance to acute oxidative stress. Cranberry slightly extended life span in flies fed with a high-fat diet. These findings suggest that cranberry promotes healthy aging by increasing stress responsiveness. Our study reveals an interaction of cranberry with dietary macronutrients and stresses the importance of considering diet composition in designing interventions for promoting healthy aging. Published by Oxford University Press on behalf of the Gerontological Society of America 2013.

Health Span-Extending Activity of Human Amniotic Membrane- and Adipose Tissue-Derived Stem Cells in F344 Rats.

PubMed

Kim, Dajeong; Kyung, Jangbeen; Park, Dongsun; Choi, Ehn-Kyoung; Kim, Kwang Sei; Shin, Kyungha; Lee, Hangyoung; Shin, Il Seob; Kang, Sung Keun; Ra, Jeong Chan; Kim, Yun-Bae

2015-10-01

Aging brings about the progressive decline in cognitive function and physical activity, along with losses of stem cell population and function. Although transplantation of muscle-derived stem/progenitor cells extended the health span and life span of progeria mice, such effects in normal animals were not confirmed. Human amniotic membrane-derived mesenchymal stem cells (AMMSCs) or adipose tissue-derived mesenchymal stem cells (ADMSCs) (1×10(6) cells per rat) were intravenously transplanted to 10-month-old male F344 rats once a month throughout their lives. Transplantation of AMMSCs and ADMSCs improved cognitive and physical functions of naturally aging rats, extending life span by 23.4% and 31.3%, respectively. The stem cell therapy increased the concentration of acetylcholine and recovered neurotrophic factors in the brain and muscles, leading to restoration of microtubule-associated protein 2, cholinergic and dopaminergic nervous systems, microvessels, muscle mass, and antioxidative capacity. The results indicate that repeated transplantation of AMMSCs and ADMSCs elongate both health span and life span, which could be a starting point for antiaging or rejuvenation effects of allogeneic or autologous stem cells with minimum immune rejection. This study demonstrates that repeated treatment with stem cells in normal animals has antiaging potential, extending health span and life span. Because antiaging and prolonged life span are issues currently of interest, these results are significant for readers and investigators. ©AlphaMed Press.

Dietary restriction in two rotifer species: the effect of the length of food deprivation on life span and reproduction.

PubMed

Weithoff, Guntram

2007-08-01

According to resource allocation theory, animals face a trade off between the allocation of resources into reproduction and into individual growth/maintenance. This trade off is reinforced when food conditions decline. It is well established in biological research that many animals increase their life span when food is in suboptimal supply for growth and/or reproduction. Such a situation of reduced food availability is called dietary restriction. An increase in life span under dietary restricted conditions is seen as a strategy to tolerate periods of food shortage so that the animals can start reproduction again when food is in greater supply. In this study, the effect of dietary restriction on life span and reproduction in two rotifer species, Cephalodella sp. and Elosa worallii, was investigated using life table experiments. The food concentration under dietary restricted conditions was below the threshold for population growth. It was (1) tested whether the rotifers start reproduction again after food replenishment, and (2) estimated whether the time scale of dietary restricted conditions is relevant for the persistence of a population in the field. Only E. worallii responded to dietary restriction with an increase in life span at the expense of reproduction. After replenishment of food, E. worallii started to reproduce again within 1 day. With an increase in the duration of dietary restricted conditions of up to 15 days, which is longer than the median life span of E. worallii under food saturation, the life span increased and the life time reproduction decreased. These results suggest that in a temporally (or spatially) variable environment, some rotifer populations can persist even during long periods of severe food deprivation.

Magnetohydrodynamic simulations of the ejection of a magnetic flux rope

NASA Astrophysics Data System (ADS)

Pagano, P.; Mackay, D. H.; Poedts, S.

2013-06-01

Context. Coronal mass ejections (CME's) are one of the most violent phenomena found on the Sun. One model to explain their occurrence is the flux rope ejection model. In this model, magnetic flux ropes form slowly over time periods of days to weeks. They then lose equilibrium and are ejected from the solar corona over a few hours. The contrasting time scales of formation and ejection pose a serious problem for numerical simulations. Aims: We simulate the whole life span of a flux rope from slow formation to rapid ejection and investigate whether magnetic flux ropes formed from a continuous magnetic field distribution, during a quasi-static evolution, can erupt to produce a CME. Methods: To model the full life span of magnetic flux ropes we couple two models. The global non-linear force-free field (GNLFFF) evolution model is used to follow the quasi-static formation of a flux rope. The MHD code ARMVAC is used to simulate the production of a CME through the loss of equilibrium and ejection of this flux rope. Results: We show that the two distinct models may be successfully coupled and that the flux rope is ejected out of our simulation box, where the outer boundary is placed at 2.5 R⊙. The plasma expelled during the flux rope ejection travels outward at a speed of 100 km s-1, which is consistent with the observed speed of CMEs in the low corona. Conclusions: Our work shows that flux ropes formed in the GNLFFF can lead to the ejection of a mass loaded magnetic flux rope in full MHD simulations. Coupling the two distinct models opens up a new avenue of research to investigate phenomena where different phases of their evolution occur on drastically different time scales. Movies are available in electronic form at http://www.aanda.org

Stem hydraulic traits and leaf water-stress tolerance are co-ordinated with the leaf phenology of angiosperm trees in an Asian tropical dry karst forest

PubMed Central

Fu, Pei-Li; Jiang, Yan-Juan; Wang, Ai-Ying; Brodribb, Tim J.; Zhang, Jiao-Lin; Zhu, Shi-Dan; Cao, Kun-Fang

2012-01-01

Background and Aims The co-occurring of evergreen and deciduous angiosperm trees in Asian tropical dry forests on karst substrates suggests the existence of different water-use strategies among species. In this study it is hypothesized that the co-occurring evergreen and deciduous trees differ in stem hydraulic traits and leaf water relationships, and there will be correlated evolution in drought tolerance between leaves and stems. Methods A comparison was made of stem hydraulic conductivity, vulnerability curves, wood anatomy, leaf life span, leaf pressure–volume characteristics and photosynthetic capacity of six evergreen and six deciduous tree species co-occurring in a tropical dry karst forest in south-west China. The correlated evolution of leaf and stem traits was examined using both traditional and phylogenetic independent contrasts correlations. Key Results It was found that the deciduous trees had higher stem hydraulic efficiency, greater hydraulically weighted vessel diameter (Dh) and higher mass-based photosynthetic rate (Am); while the evergreen species had greater xylem-cavitation resistance, lower leaf turgor-loss point water potential (π0) and higher bulk modulus of elasticity. There were evolutionary correlations between leaf life span and stem hydraulic efficiency, Am, and dry season π0. Xylem-cavitation resistance was evolutionarily correlated with stem hydraulic efficiency, Dh, as well as dry season π0. Both wood density and leaf density were closely correlated with leaf water-stress tolerance and Am. Conclusions The results reveal the clear distinctions in stem hydraulic traits and leaf water-stress tolerance between the co-occurring evergreen and deciduous angiosperm trees in an Asian dry karst forest. A novel pattern was demonstrated linking leaf longevity with stem hydraulic efficiency and leaf water-stress tolerance. The results show the correlated evolution in drought tolerance between stems and leaves. PMID:22585930

Leaf life span and the mobility of "non-mobile" mineral nutrients - the case of boron in conifers

Treesearch

Pedro J. Aphalo; Anna W. Schoettle; Tarja Lehto

2002-01-01

Nutrient conservation is considered important for the adaptation of plants to infertile environments. The importance of leaf life spans in controlling mean residence time of nutrients in plants has usually been analyzed in relation to nutrients that can be retranslocated within the plant. Longer leaf life spans increase the mean residence time of all mineral...

The Development of Memory Efficiency and Value-Directed Remembering across the Life Span: A Cross-Sectional Study of Memory and Selectivity

ERIC Educational Resources Information Center

Castel, Alan D.; Humphreys, Kathryn L.; Lee, Steve S.; Galvan, Adriana; Balota, David A.; McCabe, David P.

2011-01-01

Although attentional control and memory change considerably across the life span, no research has examined how the ability to strategically remember important information (i.e., value-directed remembering) changes from childhood to old age. The present study examined this in different age groups across the life span (N = 320, 5-96 years old). A…

Evolution of mate-harm, longevity and behaviour in male fruit flies subjected to different levels of interlocus conflict.

PubMed

Nandy, Bodhisatta; Gupta, Vanika; Sen, Sharmi; Udaykumar, Niveda; Samant, Manas Arun; Ali, Syed Zeeshan; Prasad, Nagaraj Guru

2013-09-28

Interlocus conflict predicts (a) evolution of traits, beneficial to males but detrimental to females and (b) evolution of aging and life-span under the influence of the cost of bearing these traits. However, there are very few empirical investigations shedding light on these predictions. Those that do address these issues, mostly reported response of male reproductive traits or the lack of it and do not address the life-history consequence of such evolution. Here, we test both the above mentioned predictions using experimental evolution on replicate populations of Drosophila melanogaster. We present responses observed after >45 generations of altered levels of interlocus conflict (generated by varying the operational sex ratio). Males from the male biased (high conflict, M-regime) regime evolved higher spontaneous locomotor activity and courtship frequency. Females exposed to these males were found to have higher mortality rate. Males from the female biased regime (low conflict, F-regime) did not evolve altered courtship frequency and activity. However, progeny production of females continuously exposed to F-males was significantly higher than the progeny production of females exposed to M-males indicating that the F-males are relatively benign towards their mates. We found that males from male biased regime lived shorter compared to males from the female biased regime. F-males (evolving under lower levels of sexual conflict) evolved decreased mate harming ability indicating the cost of maintenance of the suit of traits that cause mate-harm. The M-males (evolving under higher levels sexual conflict) caused higher female mortality indicating that they had evolved increased mate harming ability, possibly as a by product of increased reproduction related activity. There was a correlated evolution of life-history of the M and F-males. M-regime males lived shorter compared to the males from F-regime, possibly due to the cost of investing more in reproductive traits. In combination, these results suggest that male reproductive traits and life-history traits can evolve in response to the altered levels of interlocus sexual conflict.

Functional genomics of physiological plasticity and local adaptation in killifish.

PubMed

Whitehead, Andrew; Galvez, Fernando; Zhang, Shujun; Williams, Larissa M; Oleksiak, Marjorie F

2011-01-01

Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation.

Functional Genomics of Physiological Plasticity and Local Adaptation in Killifish

PubMed Central

Galvez, Fernando; Zhang, Shujun; Williams, Larissa M.; Oleksiak, Marjorie F.

2011-01-01

Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation. PMID:20581107

Connecting Life Span Development with the Sociology of the Life Course: A New Direction.

PubMed

Gilleard, Chris; Higgs, Paul

2016-04-01

The life course has become a topic of growing interest within the social sciences. Attempts to link this sub-discipline with life span developmental psychology have been called for but with little sign of success. In this paper, we seek to address three interlinked issues concerning the potential for a more productive interchange between life course sociology and life span psychology. The first is to try to account for the failure of these two sub-disciplines to achieve any deepening engagement with each other, despite the long-expressed desirability of that goal; the second is to draw attention to the scope for enriching the sociology of the life course through Erik Erikson's model of life span development; and the last is the potential for linking Eriksonian theory with current debates within mainstream sociology about the processes involved in 'individualisation' and 'self-reflexivity' as an alternative entry point to bring together these two fields of work.

Connecting Life Span Development with the Sociology of the Life Course: A New Direction

PubMed Central

Gilleard, Chris; Higgs, Paul

2015-01-01

The life course has become a topic of growing interest within the social sciences. Attempts to link this sub-discipline with life span developmental psychology have been called for but with little sign of success. In this paper, we seek to address three interlinked issues concerning the potential for a more productive interchange between life course sociology and life span psychology. The first is to try to account for the failure of these two sub-disciplines to achieve any deepening engagement with each other, despite the long-expressed desirability of that goal; the second is to draw attention to the scope for enriching the sociology of the life course through Erik Erikson’s model of life span development; and the last is the potential for linking Eriksonian theory with current debates within mainstream sociology about the processes involved in ‘individualisation’ and ‘self-reflexivity’ as an alternative entry point to bring together these two fields of work. PMID:27041774

Decision-making heuristics and biases across the life span.

PubMed

Strough, Jonell; Karns, Tara E; Schlosnagle, Leo

2011-10-01

We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases-the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people's everyday lives. © 2011 New York Academy of Sciences.

Decision-making heuristics and biases across the life span

PubMed Central

Strough, JoNell; Karns, Tara E.; Schlosnagle, Leo

2013-01-01

We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases—the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people’s everyday lives. PMID:22023568

Autophagy-mediated longevity is modulated by lipoprotein biogenesis

PubMed Central

Seah, Nicole E.; de Magalhaes Filho, C. Daniel; Petrashen, Anna P.; Henderson, Hope R.; Laguer, Jade; Gonzalez, Julissa; Dillin, Andrew; Hansen, Malene; Lapierre, Louis R.

2016-01-01

ABSTRACT Autophagy-dependent longevity models in C. elegans display altered lipid storage profiles, but the contribution of lipid distribution to life-span extension is not fully understood. Here we report that lipoprotein production, autophagy and lysosomal lipolysis are linked to modulate life span in a conserved fashion. We find that overexpression of the yolk lipoprotein VIT/vitellogenin reduces the life span of long-lived animals by impairing the induction of autophagy-related and lysosomal genes necessary for longevity. Accordingly, reducing vitellogenesis increases life span via induction of autophagy and lysosomal lipolysis. Life-span extension due to reduced vitellogenesis or enhanced lysosomal lipolysis requires nuclear hormone receptors (NHRs) NHR-49 and NHR-80, highlighting novel roles for these NHRs in lysosomal lipid signaling. In dietary-restricted worms and mice, expression of VIT and hepatic APOB (apolipoprotein B), respectively, are significantly reduced, suggesting a conserved longevity mechanism. Altogether, our study demonstrates that lipoprotein biogenesis is an important mechanism that modulates aging by impairing autophagy and lysosomal lipolysis. PMID:26671266

Life span effects of Hypericum perforatum extracts on Caenorhabditis elegans under heat stress.

PubMed

Kılıçgün, Hasan; Göksen, Gülden

2012-10-01

The beneficial effects of antioxidants in plants are mainly extrapolated from in vitro studies or short-term dietary supplementation studies. Due to cost and duration, relatively little is known about whether dietary antioxidants are beneficial in whole animals' life span or not. To address this question, under heat stress (35°C), Hypericum perforatum was extracted with petroleum ether and the nematodes Caenorhabditis elegans exposed to three different extract concentrations (1mg/mL, 0.1mg/mL, 0.01mg/mL) of H. perforatum. We report that Hypericum perforatum extracts did not increase life span and slow aging related increase in C. elegans. Moreover, one fraction (1mg/mL) increased declines of C. elegans life span and thermotolerance. Given this mounting evidence for life span role of H. perforatum in the presence of heat stress in vivo, the question whether H. perforatum acts as a prooxidant or an antioxidant in vivo under heat stress arises.

Life span effects of Hypericum perforatum extracts on Caenorhabditis elegans under heat stress

PubMed Central

Kılıçgün, Hasan; Göksen, Gülden

2012-01-01

Background: The beneficial effects of antioxidants in plants are mainly extrapolated from in vitro studies or short-term dietary supplementation studies. Due to cost and duration, relatively little is known about whether dietary antioxidants are beneficial in whole animals’ life span or not. Materials and Methods: To address this question, under heat stress (35°C), Hypericum perforatum was extracted with petroleum ether and the nematodes Caenorhabditis elegans exposed to three different extract concentrations (1mg/mL, 0.1mg/mL, 0.01mg/mL) of H. perforatum. Results: We report that Hypericum perforatum extracts did not increase life span and slow aging related increase in C. elegans. Moreover, one fraction (1mg/mL) increased declines of C. elegans life span and thermotolerance. Conclusion: Given this mounting evidence for life span role of H. perforatum in the presence of heat stress in vivo, the question whether H. perforatum acts as a prooxidant or an antioxidant in vivo under heat stress arises. PMID:24082638

Expressions of ecological identity across the life span of eight environmental exemplars

NASA Astrophysics Data System (ADS)

Seydel, Jennifer

While there is a substantial body of literature looking at various aspects of ecological identity and factors that influence it, there has been less work done on how an individual's ecological identity changes with time. Much of that work is limited to short segments of the life span (e.g. the impact of wilderness experiences). This dissertation attempts to address this perceived gap by investigating how the ecological identity of eight environmental exemplars changed during the course of his or her life. What has emerged from this qualitative grounded theory investigation of the lives and works of Charles Darwin, John Muir, Aldo Leopold, Marjory Stoneman Douglas, Hazel Wolf, Rachel Carson, James Lovelock and E.O. Wilson are five sequential expressions of ecological identity. These 'stages' serve as a framework to explain ecological identity as a developmental process, both fluid and continuous, rather than at) end product. The development of an ecological identity is traced, through the development of five cognitive foundations and their alignment with five emotional foundations that reflect a progression from a sensory interaction and a kinship bond with nature into a deep understanding of the interconnectedness of all aspects of the planet. The findings reveal the evolution of an ecological identity and suggest the importance of looking beyond content knowledge in the nurturing of ecological attitudes, values, and lifestyles.

Contributions of dynamic environmental signals during life-cycle transitions to early life-history traits in lodgepole pine (Pinus contorta Dougl.)

NASA Astrophysics Data System (ADS)

Liu, Y.; Wang, T.; El-Kassaby, Y. A.

2015-08-01

Environmental signals are important triggers in the life-cycle transitions and play a crucial role in the life-history evolution. Yet, very little is known about the leading ecological factors contributing to the variations of life-history traits in perennial plants. This paper explores both the causes and consequences for the evolution of life-history traits (i.e., seed dormancy and size) in lodgepole pine (Pinus contorta Dougl.) across British Columbia (B.C.), Canada. We selected 83 logepole pine populations covering 22 ecosystem zones of B.C. and through their geographic coordinate, 197 climatic variables were generated accordingly for the reference (1961-1990) and future (2041-2070) periods. We found that dynamic climatic variables rather than constant geographic variables are the true environmental driving forces in seed dormancy and size variations and thus provide reliable predictors in response to global climate change. Evapotranspiration and precipitation in the plant-to-seed chronology are the most critical climate variables for seed dormancy and size variations, respectively. Hence, we predicted that levels of seed dormancy in lodgepole pine would increase across large tracts of B.C. in 2050s. Winter-chilling is able to increase the magnitude of life-history plasticity and lower the bet-hedge strategy in the seed-to-plant transition; however, winter-chilling is likely to be insufficient in the north of 49° N in 2050s, which may delay germination while unfavourable conditions during dry summers may result in adverse consequences in the survival of seedlings owing to extended germination span.

Paternal smoking habits affect the reproductive life span of daughters.

PubMed

Fukuda, Misao; Fukuda, Kiyomi; Shimizu, Takashi; Nobunaga, Miho; Andersen, Elisabeth Wreford; Byskov, Anne Grete; Andersen, Claus Yding

2011-06-30

The present study assessed whether the smoking habits of fathers around the time of conception affected the period in which daughters experienced menstrual cycles (i.e., the reproductive life span). The study revealed that the smoking habits of the farther shortened the daughters' reproductive life span compared with daughters whose fathers did not smoke. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Structural covariance networks across the life span, from 6 to 94 years of age.

PubMed

DuPre, Elizabeth; Spreng, R Nathan

2017-10-01

Structural covariance examines covariation of gray matter morphology between brain regions and across individuals. Despite significant interest in the influence of age on structural covariance patterns, no study to date has provided a complete life span perspective-bridging childhood with early, middle, and late adulthood-on the development of structural covariance networks. Here, we investigate the life span trajectories of structural covariance in six canonical neurocognitive networks: default, dorsal attention, frontoparietal control, somatomotor, ventral attention, and visual. By combining data from five open-access data sources, we examine the structural covariance trajectories of these networks from 6 to 94 years of age in a sample of 1,580 participants. Using partial least squares, we show that structural covariance patterns across the life span exhibit two significant, age-dependent trends. The first trend is a stable pattern whose integrity declines over the life span. The second trend is an inverted-U that differentiates young adulthood from other age groups. Hub regions, including posterior cingulate cortex and anterior insula, appear particularly influential in the expression of this second age-dependent trend. Overall, our results suggest that structural covariance provides a reliable definition of neurocognitive networks across the life span and reveal both shared and network-specific trajectories.

ω-6 Polyunsaturated fatty acids extend life span through the activation of autophagy

PubMed Central

O'Rourke, Eyleen J.; Kuballa, Petric; Xavier, Ramnik; Ruvkun, Gary

2013-01-01

Adaptation to nutrient scarcity depends on the activation of metabolic programs to efficiently use internal reserves of energy. Activation of these programs in abundant food regimens can extend life span. However, the common molecular and metabolic changes that promote adaptation to nutritional stress and extend life span are mostly unknown. Here we present a response to fasting, enrichment of ω-6 polyunsaturated fatty acids (PUFAs), which promotes starvation resistance and extends Caenorhabditis elegans life span. Upon fasting, C. elegans induces the expression of a lipase, which in turn leads to an enrichment of ω-6 PUFAs. Supplementing C. elegans culture media with these ω-6 PUFAs increases their resistance to starvation and extends their life span in conditions of food abundance. Supplementation of C. elegans or human epithelial cells with these ω-6 PUFAs activates autophagy, a cell recycling mechanism that promotes starvation survival and slows aging. Inactivation of C. elegans autophagy components reverses the increase in life span conferred by supplementing the C. elegans diet with these fasting-enriched ω-6 PUFAs. We propose that the salubrious effects of dietary supplementation with ω-3/6 PUFAs (fish oils) that have emerged from epidemiological studies in humans may be due to a similar activation of autophagic programs. PMID:23392608

Genes that regulate both development and longevity in Caenorhabditis elegans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsen, P.L.; Albert, P.S.; Riddle, D.L.

1995-04-01

The nematode Caenorhabditis elegans responds to conditions of overcrowding and limited food by arresting development as a dauer larva. Genetic analysis of mutations that alter dauer larva formation (daf mutations) is presented along with an updated genetic pathway for dauer vs. nondauer development. Mutations in the daf-2 and daf-23 genes double adult life span, whereas mutations in four other dauer-constitutive genes positioned in a separate branch of this pathway (daf-1, daf-4, daf-7 and daf-8) do not. The increased life spans are suppressed completely by a daf-16 mutation and partially in a daf-2; daf-18 double mutant. A genetic pathway for determinationmore » of adult life span is presented based on the same strains and growth conditions used to characterize Daf phenotypes. Both dauer larva formation and adult life span are affected in daf-2; daf-12 double mutants in an allele-specific manner. Mutations in daf-12 do not extend adult life span, but certain combinations of daf-2 and daf-12 mutant alleles nearly quadruple it. This synergistic effect, which does not equivalently extend the fertile period, is the largest genetic extension of life span yet observed in a metazoan. 47 refs., 7 figs., 5 tabs.« less

Genome-wide screen in Saccharomyces cerevisiae identifies vacuolar protein sorting, autophagy, biosynthetic, and tRNA methylation genes involved in life span regulation.

PubMed

Fabrizio, Paola; Hoon, Shawn; Shamalnasab, Mehrnaz; Galbani, Abdulaye; Wei, Min; Giaever, Guri; Nislow, Corey; Longo, Valter D

2010-07-15

The study of the chronological life span of Saccharomyces cerevisiae, which measures the survival of populations of non-dividing yeast, has resulted in the identification of homologous genes and pathways that promote aging in organisms ranging from yeast to mammals. Using a competitive genome-wide approach, we performed a screen of a complete set of approximately 4,800 viable deletion mutants to identify genes that either increase or decrease chronological life span. Half of the putative short-/long-lived mutants retested from the primary screen were confirmed, demonstrating the utility of our approach. Deletion of genes involved in vacuolar protein sorting, autophagy, and mitochondrial function shortened life span, confirming that respiration and degradation processes are essential for long-term survival. Among the genes whose deletion significantly extended life span are ACB1, CKA2, and TRM9, implicated in fatty acid transport and biosynthesis, cell signaling, and tRNA methylation, respectively. Deletion of these genes conferred heat-shock resistance, supporting the link between life span extension and cellular protection observed in several model organisms. The high degree of conservation of these novel yeast longevity determinants in other species raises the possibility that their role in senescence might be conserved.

Structural covariance networks across the life span, from 6 to 94 years of age

PubMed Central

DuPre, Elizabeth; Spreng, R. Nathan

2017-01-01

Structural covariance examines covariation of gray matter morphology between brain regions and across individuals. Despite significant interest in the influence of age on structural covariance patterns, no study to date has provided a complete life span perspective—bridging childhood with early, middle, and late adulthood—on the development of structural covariance networks. Here, we investigate the life span trajectories of structural covariance in six canonical neurocognitive networks: default, dorsal attention, frontoparietal control, somatomotor, ventral attention, and visual. By combining data from five open-access data sources, we examine the structural covariance trajectories of these networks from 6 to 94 years of age in a sample of 1,580 participants. Using partial least squares, we show that structural covariance patterns across the life span exhibit two significant, age-dependent trends. The first trend is a stable pattern whose integrity declines over the life span. The second trend is an inverted-U that differentiates young adulthood from other age groups. Hub regions, including posterior cingulate cortex and anterior insula, appear particularly influential in the expression of this second age-dependent trend. Overall, our results suggest that structural covariance provides a reliable definition of neurocognitive networks across the life span and reveal both shared and network-specific trajectories. PMID:29855624

Metabotypes with properly functioning mitochondria and anti-inflammation predict extended productive life span in dairy cows

PubMed Central

Huber, K.; Dänicke, S.; Rehage, J.; Sauerwein, H.; Otto, W.; Rolle-Kampczyk, U.; von Bergen, M.

2016-01-01

The failure to adapt metabolism to the homeorhetic demands of lactation is considered as a main factor in reducing the productive life span of dairy cows. The so far defined markers of production performance and metabolic health in dairy cows do not predict the length of productive life span satisfyingly. This study aimed to identify novel pathways and biomarkers related to productive life in dairy cows by means of (targeted) metabolomics. In a longitudinal study from 42 days before up to 100 days after parturition, we identified metabolites such as long-chain acylcarnitines and biogenic amines associated with extended productive life spans. These metabolites are mainly secreted by the liver and depend on the functionality of hepatic mitochondria. The concentrations of biogenic amines and some acylcarnitines differed already before the onset of lactation thus indicating their predictive potential for continuation or early ending of productive life. PMID:27089826

Metabotypes with properly functioning mitochondria and anti-inflammation predict extended productive life span in dairy cows.

PubMed

Huber, K; Dänicke, S; Rehage, J; Sauerwein, H; Otto, W; Rolle-Kampczyk, U; von Bergen, M

2016-04-19

The failure to adapt metabolism to the homeorhetic demands of lactation is considered as a main factor in reducing the productive life span of dairy cows. The so far defined markers of production performance and metabolic health in dairy cows do not predict the length of productive life span satisfyingly. This study aimed to identify novel pathways and biomarkers related to productive life in dairy cows by means of (targeted) metabolomics. In a longitudinal study from 42 days before up to 100 days after parturition, we identified metabolites such as long-chain acylcarnitines and biogenic amines associated with extended productive life spans. These metabolites are mainly secreted by the liver and depend on the functionality of hepatic mitochondria. The concentrations of biogenic amines and some acylcarnitines differed already before the onset of lactation thus indicating their predictive potential for continuation or early ending of productive life.

Trehalose extends longevity in the nematode Caenorhabditis elegans.

PubMed

Honda, Yoko; Tanaka, Masashi; Honda, Shuji

2010-08-01

Trehalose is a disaccharide of glucose found in diverse organisms and is suggested to act as a stress protectant against heat, cold, desiccation, anoxia, and oxidation. Here, we demonstrate that treatment of Caenorhabditis elegans with trehalose starting from the young-adult stage extended the mean life span by over 30% without any side effects. Surprisingly, trehalose treatment starting even from the old-adult stage shortly thereafter retarded the age-associated decline in survivorship and extended the remaining life span by 60%. Demographic analyses of age-specific mortality rates revealed that trehalose extended the life span by lowering age-independent vulnerability. Moreover, trehalose increased the reproductive span and retarded the age-associated decrease in pharyngeal-pumping rate and the accumulation of lipofuscin autofluorescence. Trehalose also enhanced thermotolerance and reduced polyglutamine aggregation. These results suggest that trehalose suppressed aging by counteracting internal or external stresses that disrupt protein homeostasis. On the other hand, the life span-extending effect of trehalose was abolished in long-lived insulin/IGF-1-like receptor (daf-2) mutants. RNA interference-mediated inactivation of the trehalose-biosynthesis genes trehalose-6-phosphate synthase-1 (tps-1) and tps-2, which are known to be up-regulated in daf-2 mutants, decreased the daf-2 life span. These findings indicate that a reduction in insulin/IGF-1-like signaling extends life span, at least in part, through the aging-suppressor function of trehalose. Trehalose may be a lead compound for potential nutraceutical intervention of the aging process.

Working memory and inhibitory control across the life span: Intrusion errors in the Reading Span Test.

PubMed

Robert, Christelle; Borella, Erika; Fagot, Delphine; Lecerf, Thierry; de Ribaupierre, Anik

2009-04-01

The aim of this study was to examine to what extent inhibitory control and working memory capacity are related across the life span. Intrusion errors committed by children and younger and older adults were investigated in two versions of the Reading Span Test. In Experiment 1, a mixed Reading Span Test with items of various list lengths was administered. Older adults and children recalled fewer correct words and produced more intrusions than did young adults. Also, age-related differences were found in the type of intrusions committed. In Experiment 2, an adaptive Reading Span Test was administered, in which the list length of items was adapted to each individual's working memory capacity. Age groups differed neither on correct recall nor on the rate of intrusions, but they differed on the type of intrusions. Altogether, these findings indicate that the availability of attentional resources influences the efficiency of inhibition across the life span.

Reduced Ssy1-Ptr3-Ssy5 (SPS) signaling extends replicative life span by enhancing NAD+ homeostasis in Saccharomyces cerevisiae.

PubMed

Tsang, Felicia; James, Christol; Kato, Michiko; Myers, Victoria; Ilyas, Irtqa; Tsang, Matthew; Lin, Su-Ju

2015-05-15

Attenuated nutrient signaling extends the life span in yeast and higher eukaryotes; however, the mechanisms are not completely understood. Here we identify the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway as a novel longevity factor. A null mutation of SSY5 (ssy5Δ) increases replicative life span (RLS) by ∼50%. Our results demonstrate that several NAD(+) homeostasis factors play key roles in this life span extension. First, expression of the putative malate-pyruvate NADH shuttle increases in ssy5Δ cells, and deleting components of this shuttle, MAE1 and OAC1, largely abolishes RLS extension. Next, we show that Stp1, a transcription factor of the SPS pathway, directly binds to the promoter of MAE1 and OAC1 to regulate their expression. Additionally, deletion of SSY5 increases nicotinamide riboside (NR) levels and phosphate-responsive (PHO) signaling activity, suggesting that ssy5Δ increases NR salvaging. This increase contributes to NAD(+) homeostasis, partially ameliorating the NAD(+) deficiency and rescuing the short life span of the npt1Δ mutant. Moreover, we observed that vacuolar phosphatase, Pho8, is partially required for ssy5Δ-mediated NR increase and RLS extension. Together, our studies present evidence that supports SPS signaling is a novel NAD(+) homeostasis factor and ssy5Δ-mediated life span extension is likely due to concomitantly increased mitochondrial and vacuolar function. Our findings may contribute to understanding the molecular basis of NAD(+) metabolism, cellular life span, and diseases associated with NAD(+) deficiency and aging. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Influence of resveratrol on oxidative stress resistance and life span in Caenorhabditis elegans.

PubMed

Chen, Wei; Rezaizadehnajafi, Leila; Wink, Michael

2013-05-01

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a polyphenol from red wine, has been reported to be beneficial in cases of ageing-related cardiovascular and neurodegenerative diseases owing to its property to reduce oxidative stress. Previous studies on the longevity promoting effect of resveratrol have been partly inconclusive, therefore we set out to investigate whether resveratrol at least promoted longevity in Caenorhabditis elegans under acute oxidative stress conditions. C. elegans was cultured under standard conditions with or without resveratrol. After exposure to juglone-induced acute oxidative stress, the survival rate and hsp-16.2::GFP expression were measured. The influence of resveratrol on life span was recorded also under oxidative stress induced by high glucose concentrations in the growth medium. No extension of the normal life span of C. elegans was observed either in liquid or solid growth media containing different concentrations of resveratrol. However, resveratrol alleviated juglone-induced lethal oxidative stress, and significantly prolonged the life span of C. elegans under conditions of acute oxidative damage and oxidative stress caused by high concentrations of glucose. Resveratrol, as an antioxidant, ameliorated oxidative stress in vivo but did not extend the life span of C. elegans under normal conditions. However, resveratrol did extend life span under conditions of oxidative stress. © 2013 The Authors. JPP © 2013 Royal Pharmaceutical Society.

Immortalization of Human Fetal Cells: The Life Span of Umbilical Cord Blood-derived Cells Can Be Prolonged without Manipulating p16INK4a/RB Braking PathwayD⃞

PubMed Central

Terai, Masanori; Uyama, Taro; Sugiki, Tadashi; Li, Xiao-Kang; Umezawa, Akihiro; Kiyono, Tohru

2005-01-01

Human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) are expected to serve as an excellent alternative to bone marrow-derived human mesenchymal stem cells. However, it is difficult to study them because of their limited life span. To overcome this problem, we attempted to produce a strain of UCBMSCs with a long life span and to investigate whether the strain could maintain phenotypes in vitro. UCBMSCs were infected with retrovirus carrying the human telomerase reverse transcriptase (hTERT) to prolong their life span. The UCBMSCs underwent 30 population doublings (PDs) and stopped dividing at PD 37. The UCBMSCs newly established with hTERT (UCBTERTs) proliferated for >120 PDs. The p16INK4a/RB braking pathway leading to senescence can be inhibited by introduction of Bmi-1, a polycomb-group gene, and human papillomavirus type 16 E7, but the extension of the life span of the UCBMSCs with hTERT did not require inhibition of the p16INK4a/RB pathway. The characteristics of the UCBTERTs remained unchanged during the prolongation of life span. UCBTERTs provide a powerful model for further study of cellular senescence and for future application to cell-based therapy by using umbilical cord blood cells. PMID:15647378

Twelve fundamental life histories evolving through allocation-dependent fecundity and survival.

PubMed

Johansson, Jacob; Brännström, Åke; Metz, Johan A J; Dieckmann, Ulf

2018-03-01

An organism's life history is closely interlinked with its allocation of energy between growth and reproduction at different life stages. Theoretical models have established that diminishing returns from reproductive investment promote strategies with simultaneous investment into growth and reproduction (indeterminate growth) over strategies with distinct phases of growth and reproduction (determinate growth). We extend this traditional, binary classification by showing that allocation-dependent fecundity and mortality rates allow for a large diversity of optimal allocation schedules. By analyzing a model of organisms that allocate energy between growth and reproduction, we find twelve types of optimal allocation schedules, differing qualitatively in how reproductive allocation increases with body mass. These twelve optimal allocation schedules include types with different combinations of continuous and discontinuous increase in reproduction allocation, in which phases of continuous increase can be decelerating or accelerating. We furthermore investigate how this variation influences growth curves and the expected maximum life span and body size. Our study thus reveals new links between eco-physiological constraints and life-history evolution and underscores how allocation-dependent fitness components may underlie biological diversity.

Sustained Attention Across the Life Span in a Sample of 10,000: Dissociating Ability and Strategy.

PubMed

Fortenbaugh, Francesca C; DeGutis, Joseph; Germine, Laura; Wilmer, Jeremy B; Grosso, Mallory; Russo, Kathryn; Esterman, Michael

2015-09-01

Normal and abnormal differences in sustained visual attention have long been of interest to scientists, educators, and clinicians. Still lacking, however, is a clear understanding of how sustained visual attention varies across the broad sweep of the human life span. In the present study, we filled this gap in two ways. First, using an unprecedentedly large 10,430-person sample, we modeled age-related differences with substantially greater precision than have prior efforts. Second, using the recently developed gradual-onset continuous performance test (gradCPT), we parsed sustained-attention performance over the life span into its ability and strategy components. We found that after the age of 15 years, the strategy and ability trajectories saliently diverge. Strategy becomes monotonically more conservative with age, whereas ability peaks in the early 40s and is followed by a gradual decline in older adults. These observed life-span trajectories for sustained attention are distinct from results of other life-span studies focusing on fluid and crystallized intelligence. © The Author(s) 2015.

Role of metabolic rate and DNA-repair in Drosophila aging Implications for the mitochondrial mutation theory of aging

NASA Technical Reports Server (NTRS)

Miquel, J.; Binnard, R.; Fleming, J. E.

1983-01-01

The notion that injury to mitochondrial DNA is a cause of intrinsic aging was tested by correlating the different respiration rates of several wild strains of Drosophila melanogaster with the life-spans. Respiration rate and aging in a mutant of D. melanogaster deficient in postreplication repair were also investigated. In agreement with the rate of living theory, there was an inverse relation between oxygen consumption and median life-span in flies having normal DNA repair. The mutant showed an abnormally low life-span as compared to the controls and also exhibited significant deficiency in mating fitness and a depressed metabolic rate. Therefore, the short life-span of the mutant may be due to the congenital condition rather than to accelerated aging.

Understanding retirement: the promise of life-span developmental frameworks.

PubMed

Löckenhoff, Corinna E

2012-09-01

The impending retirement of large population cohorts creates a pressing need for practical interventions to optimize outcomes at the individual and societal level. This necessitates comprehensive theoretical models that acknowledge the multi-layered nature of the retirement process and shed light on the dynamic mechanisms that drive longitudinal patterns of adjustment. The present commentary highlights ways in which contemporary life-span developmental frameworks can inform retirement research, drawing on the specific examples of Bronfenbrenner's Ecological Model, Baltes and Baltes Selective Optimization with Compensation Framework, Schulz and Heckhausen's Motivational Theory of Life-Span Development, and Carstensen's Socioemotional Selectivity Theory. Ultimately, a life-span developmental perspective on retirement offers not only new interpretations of known phenomena but may also help to identify novel directions for future research as well as promising pathways for interventions.

Adaptive prolonged postreproductive life span in killer whales.

PubMed

Foster, Emma A; Franks, Daniel W; Mazzi, Sonia; Darden, Safi K; Balcomb, Ken C; Ford, John K B; Croft, Darren P

2012-09-14

Prolonged life after reproduction is difficult to explain evolutionarily unless it arises as a physiological side effect of increased longevity or it benefits related individuals (i.e., increases inclusive fitness). There is little evidence that postreproductive life spans are adaptive in nonhuman animals. By using multigenerational records for two killer whale (Orcinus orca) populations in which females can live for decades after their final parturition, we show that postreproductive mothers increase the survival of offspring, particularly their older male offspring. This finding may explain why female killer whales have evolved the longest postreproductive life span of all nonhuman animals.

Endosomal protein sorting and autophagy genes contribute to the regulation of yeast life span.

PubMed

Longo, Valter D; Nislow, Corey; Fabrizio, Paola

2010-11-01

Accumulating evidence from various organisms points to a role for autophagy in the regulation of life span. By performing a genome-wide screen to identify novel life span determinants in Saccharomyces cerevisiae, we have obtained further insights into the autophagy-related and -unrelated degradation processes that may be important for preventing cellular senescence. The generation of multivesicular bodies and their fusion with the vacuole in the endosomal pathway emerged as novel cell functions involved in yeast chronological survival and longevity extension.

Life and Self Meaning: The Process of Their Creation.

ERIC Educational Resources Information Center

Weenolsen, Patricia

Research has not addressed issues of life meaning in a life-span developmental framework. The Loss and Transcendence paradigm was developed as a humanistic-existential approach to life-span development which has as its central theme the concept that individuals are in a continuous process of creating their lives and their selves. To explore loss…

Evaluation of resveratrol, green tea extract, curcumin, oxaloacetic acid, and medium-chain triglyceride oil on life span of genetically heterogeneous mice.

PubMed

Strong, Randy; Miller, Richard A; Astle, Clinton M; Baur, Joseph A; de Cabo, Rafael; Fernandez, Elizabeth; Guo, Wen; Javors, Martin; Kirkland, James L; Nelson, James F; Sinclair, David A; Teter, Bruce; Williams, David; Zaveri, Nurulain; Nadon, Nancy L; Harrison, David E

2013-01-01

The National Institute on Aging Interventions Testing Program (ITP) was established to evaluate agents that are hypothesized to increase life span and/or health span in genetically heterogeneous mice. Each compound is tested in parallel at three test sites. It is the goal of the ITP to publish all results, negative or positive. We report here on the results of lifelong treatment of mice, beginning at 4 months of age, with each of five agents, that is, green tea extract (GTE), curcumin, oxaloacetic acid, medium-chain triglyceride oil, and resveratrol, on the life span of genetically heterogeneous mice. Each agent was administered beginning at 4 months of age. None of these five agents had a statistically significant effect on life span of male or female mice, by log-rank test, at the concentrations tested, although a secondary analysis suggested that GTE might diminish the risk of midlife deaths in females only.

Evaluation of Resveratrol, Green Tea Extract, Curcumin, Oxaloacetic Acid, and Medium-Chain Triglyceride Oil on Life Span of Genetically Heterogeneous Mice

PubMed Central

Miller, Richard A.; Astle, Clinton M.; Baur, Joseph A.; de Cabo, Rafael; Fernandez, Elizabeth; Guo, Wen; Javors, Martin; Kirkland, James L.; Nelson, James F.; Sinclair, David A.; Teter, Bruce; Williams, David; Zaveri, Nurulain; Nadon, Nancy L.; Harrison, David E.

2013-01-01

The National Institute on Aging Interventions Testing Program (ITP) was established to evaluate agents that are hypothesized to increase life span and/or health span in genetically heterogeneous mice. Each compound is tested in parallel at three test sites. It is the goal of the ITP to publish all results, negative or positive. We report here on the results of lifelong treatment of mice, beginning at 4 months of age, with each of five agents, that is, green tea extract (GTE), curcumin, oxaloacetic acid, medium-chain triglyceride oil, and resveratrol, on the life span of genetically heterogeneous mice. Each agent was administered beginning at 4 months of age. None of these five agents had a statistically significant effect on life span of male or female mice, by log-rank test, at the concentrations tested, although a secondary analysis suggested that GTE might diminish the risk of midlife deaths in females only. PMID:22451473

A Holistic Model for Wellness and Prevention over the Life Span.

ERIC Educational Resources Information Center

Witmer, J. Melvin; Sweeney, Thomas J.

1992-01-01

Presents integrated paradigm for wellness and prevention over the life span for purpose of theory building, research, clinical application, education, advocacy, and consciousness raising. Model described includes 11 characteristics desirable for optimal health and functioning. Notes characteristics are expressed through five life tasks of…

Cessation of reproduction: an analytic view of menopause.

PubMed

Spencer, Richard P

2002-10-01

While there is evidence for genetic control of ovarian and follicular development, only recently have reports appeared on genetic components involved in ovarian failure. Unlike predictions of a stable population, age at menarche is decreasing, while female life span is increasing. This leads to examination of genotype-environment interactions. Evolution of the large human brain size has been accompanied by a reduction in size of the gastrointestinal tract. Consequences, in terms of altered diet and effects on menarche/menstruation/menopause were discussed. In the earliest days of human evolution, genotoxic agents and marginal diets could have produced heritable changes in cessation of menstruation. Toxic alterations may still be apparent, such as epidemiological studies on the effects of smoking on age at menopause. Attempts to reconstruct some of the recent past history, from coprolites to findings in frozen human specimens, have to be extended still further into the past.

Explanatory style across the life span: evidence for stability over 52 years.

PubMed

Burns, M O; Seligman, M E

1989-03-01

Analyzed explanatory style across the life span. 30 Ss whose average age was 72 responded to questions about their current life and provided diaries or letters written in their youth, an average of 52 years earlier. A blind content analysis of explanatory style derived from these 2 sources revealed that explanatory style for negative events was stable throughout adult life (r = .54, p less than .002). In contrast, there appeared to be no stability of explanatory style for positive events between the same 2 time periods. These results suggest that explanatory style for negative events may persist across the life span and may constitute an enduring risk factor for depression, low achievement, and physical illness.

Contributions of dynamic environmental signals during life-cycle transitions to early life-history traits in lodgepole pine (Pinus contorta Dougl.)

NASA Astrophysics Data System (ADS)

Liu, Yang; Wang, Tongli; El-Kassaby, Yousry A.

2016-05-01

Environmental signals are important triggers in the life-cycle transitions and play a crucial role in the life-history evolution. Yet very little is known about the leading ecological factors contributing to the variations of life-history traits in perennial plants. This paper explores both the causes and consequences for the evolution of life-history traits (i.e., seed dormancy and size) in lodgepole pine (Pinus contorta Dougl.) across British Columbia (B.C.), Canada. We selected 83 logepole pine populations covering 22 ecosystem zones of B.C. and through their geographic coordinate, 197 climatic variables were generated accordingly for the reference (1961-1990) and future (2041-2070) periods. We found that dynamic climatic variables rather than constant geographic variables are the true environmental driving forces in seed dormancy and size variations and thus provide reliable predictors in response to global climate change. Evapotranspiration and precipitation in the plant-to-seed chronology are the most critical climate variables for seed dormancy and size variations, respectively. Hence, we predicted that levels of seed dormancy in lodgepole pine would increase across large tracts of B.C. in 2050s. Winter-chilling is able to increase the magnitude of life-history plasticity and lower the bet-hedge strategy in the seed-to-plant transition; however, winter-chilling is likely to be insufficient in the north of 49° N in 2050s, which may delay germination while unfavorable conditions during dry summers may result in adverse consequences in the survival of seedlings owing to extended germination span. These findings provide useful information to studies related to assessments of seed transfer and tree adaptation.

The Cost of Uncertain Life Span*

PubMed Central

Edwards, Ryan D.

2012-01-01

A considerable amount of uncertainty surrounds the length of human life. The standard deviation in adult life span is about 15 years in the U.S., and theory and evidence suggest it is costly. I calibrate a utility-theoretic model of preferences over length of life and show that one fewer year in standard deviation is worth about half a mean life year. Differences in the standard deviation exacerbate cross-sectional differences in life expectancy between the U.S. and other industrialized countries, between rich and poor countries, and among poor countries. Accounting for the cost of life-span variance also appears to amplify recently discovered patterns of convergence in world average human well-being. This is partly for methodological reasons and partly because unconditional variance in human length of life, primarily the component due to infant mortality, has exhibited even more convergence than life expectancy. PMID:22368324

Getting the measure of extinction.

PubMed

Mace, G

1998-01-01

Like all species, plants, mammals, and birds have been subject to extinction as a fundamental part of evolution. Indeed, only about 2-4% of all the species that have ever lived during the 600 million years of the fossil record still survive today. Looking at the fossil record, it can be said that invertebrate species and mammals have had an average life span of 5-10 and 1-2 million years, respectively. More recent extinction records for birds and mammals lost over the last half of the century indicate that 1 out of 14,000 species becomes extinct each year, giving each species an average life span of 10,000 years--100 to 1000 times shorter than the lifetime of species in the fossil record. Drawing on the World's Conservation Union Red List of threatened animals (1996), species lifetimes of birds, mammals and reptiles are estimated at 300-500 years and 100-1000 years across broader groups. In general, these estimates show that extinction rates today are 1000 to 10,000 times higher than in the past, making current rates of species loss at least equivalent to the mass extinctions in the past. A major difference, however, is the fact that almost all extinctions that have transpired today are due to the impact of human activities.

Genetic erosion in wild populations makes resistance to a pathogen more costly.

PubMed

Luquet, Emilien; Garner, Trenton W J; Léna, Jean-Paul; Bruel, Christophe; Joly, Pierre; Lengagne, Thierry; Grolet, Odile; Plénet, Sandrine

2012-06-01

Populations that have suffered from genetic erosion are expected to exhibit reduced average trait values or decreased variation in adaptive traits when experiencing periodic or emergent stressors such as infectious disease. Genetic erosion may consequentially modify the ability of a potential host population to cope with infectious disease emergence. We experimentally investigate this relationship between genetic variability and host response to exposure to an infectious agent both in terms of susceptibility to infection and indirect parasite-mediated responses that also impact fitness. We hypothesized that the deleterious consequences of exposure to the pathogen (Batrachochytrium dendrobatidis) would be more severe for tadpoles descended from European treefrog (Hyla arborea) populations lacking genetic variability. Although all exposed tadpoles lacked detectable infection, we detected this relationship for some indirect host responses, predominantly in genetically depleted animals, as well as an interaction between genetic variability and pathogen dose on life span during the postmetamorphic period. Lack of infection and a decreased mass and postmetamorphic life span in low genetic diversity tadpoles lead us to conclude that genetic erosion, while not affecting the ability to mount effective resistance strategies, also erodes the capacity to invest in resistance, increased tadpole growth rate, and metamorphosis relatively simultaneously. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

Life-Span Developmental Psychology: Non-Normative Life Events. A Review of the Seventh West Virginia University Life-Span Developmental Psychology Conference.

ERIC Educational Resources Information Center

Richardson, Gale A.; Kwiatkowski, Bonnie M.

1981-01-01

Topics covered in this conference included parenting, terminal illness, the birth of severely disabled children, rape and family violence, separation and divorce, and hospitalization, and dealt with a wide range of methodologies and age periods. (Author/RH)

The Impact of Life Stages on Parent-Child Relationships: A Comparative Look at Japanese & American University Students

ERIC Educational Resources Information Center

Takei, Yoshimitsu; Honda, Tokio; Shieh, Sheau-Hue

2007-01-01

Adolescence is often considered a period in a person's life when important physiological and emotional changes occur. When discussing adolescence, however, it should not be forgotten that it is just another stage in one's life span between birth and death. By adopting a life-span perspective, researchers are more likely to consider contextual…

Artificial neural networks in biology and chemistry: the evolution of a new analytical tool.

PubMed

Cartwright, Hugh M

2008-01-01

Once regarded as an eccentric and unpromising algorithm for the analysis of scientific data, the neural network has been developed in the last decade into a powerful computational tool. Its use now spans all areas of science, from the physical sciences and engineering to the life sciences and allied subjects. Applications range from the assessment of epidemiological data or the deconvolution of spectra to highly practical applications, such as the electronic nose. This introductory chapter considers briefly the growth in the use of neural networks and provides some general background in preparation for the more detailed chapters that follow.

Disks around stars and the growth of planetary systems.

PubMed

Greaves, Jane S

2005-01-07

Circumstellar disks play a vital evolutionary role, providing a way to move gas inward and onto a young star. The outward transfer of angular momentum allows the star to contract without breaking up, and the remnant disk of gas and particles is the reservoir for forming planets. High-resolution spectroscopy is uncovering planetary dynamics and motion within the remnant disk, and imaging at infrared to millimeter wavelengths resolves disk structure over billions of years of evolution. Most stars are born with a disk, and models of planet formation need to form such bodies from the disk material within the disk's 10-million-year life-span.

Geologic Evolution of Eastern Hellas, Mars: Styles and Timing of Volatile-driven Activity

NASA Technical Reports Server (NTRS)

Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.

2004-01-01

The east rim of the Hellas basin and the surrounding highlands comprise a geologically significant region for evaluating volatile abundance, volatile distribution and cycling, and potential changes in Martian environmental conditions. This region of the Martian surface exhibits landforms shaped by a diversity of geologic processes and has a well-preserved geologic record, with exposures of Noachian, Hesperian, and Amazonian units, as well as spans a wide range in both latitude and elevation due to the magnitude of Hellas basin. In addition, geologically contemporaneous volcanism and volatile-driven activity in the circum-Hellas highlands provide important ingredients for creating habitats for potential Martian life.

Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica

PubMed Central

Arnaud-Haond, Sophie; Duarte, Carlos M.; Diaz-Almela, Elena; Marbà, Núria; Sintes, Tomas; Serrão, Ester A.

2012-01-01

The maximum size and age that clonal organisms can reach remains poorly known, although we do know that the largest natural clones can extend over hundreds or thousands of metres and potentially live for centuries. We made a review of findings to date, which reveal that the maximum clone age and size estimates reported in the literature are typically limited by the scale of sampling, and may grossly underestimate the maximum age and size of clonal organisms. A case study presented here shows the occurrence of clones of slow-growing marine angiosperm Posidonia oceanica at spatial scales ranging from metres to hundreds of kilometres, using microsatellites on 1544 sampling units from a total of 40 locations across the Mediterranean Sea. This analysis revealed the presence, with a prevalence of 3.5 to 8.9%, of very large clones spreading over one to several (up to 15) kilometres at the different locations. Using estimates from field studies and models of the clonal growth of P. oceanica, we estimated these large clones to be hundreds to thousands of years old, suggesting the evolution of general purpose genotypes with large phenotypic plasticity in this species. These results, obtained combining genetics, demography and model-based calculations, question present knowledge and understanding of the spreading capacity and life span of plant clones. These findings call for further research on these life history traits associated with clonality, considering their possible ecological and evolutionary implications. PMID:22312426

Evolution, mutations, and human longevity: European royal and noble families.

PubMed

Gavrilova, N S; Gavrilov, L A; Evdokushkina, G N; Semyonova, V G; Gavrilova, A L; Evdokushkina, N N; Kushnareva, Y E; Kroutko, V N; Andreyev AYu

1998-08-01

The evolutionary theory of aging predicts that the equilibrium gene frequency for deleterious mutations should increase with age at onset of mutation action because of weaker (postponed) selection against later-acting mutations. According to this mutation accumulation hypothesis, one would expect the genetic variability for survival (additive genetic variance) to increase with age. The ratio of additive genetic variance to the observed phenotypic variance (the heritability of longevity) can be estimated most reliably as the doubled slope of the regression line for offspring life span on paternal age at death. Thus, if longevity is indeed determined by late-acting deleterious mutations, one would expect this slope to become steeper at higher paternal ages. To test this prediction of evolutionary theory of aging, we computerized and analyzed the most reliable and accurate genealogical data on longevity in European royal and noble families. Offspring longevity for each sex (8409 records for males and 3741 records for females) was considered as a dependent variable in the multiple regression model and as a function of three independent predictors: paternal age at death (for estimation of heritability of life span), paternal age at reproduction (control for parental age effects), and cohort life expectancy (control for cohort and secular trends and fluctuations). We found that the regression slope for offspring longevity as a function of paternal longevity increases with paternal longevity, as predicted by the evolutionary theory of aging and by the mutation accumulation hypothesis in particular.

Identity, prudential concern, and extended lives.

PubMed

Glannon, Walter

2002-06-01

Recent advances in human genetics suggest that it may become possible to genetically manipulate telomerase and embryonic stem cells to alter the mechanisms of aging and extend the human life span. But a life span significantly longer than the present norm would be undesirable because it would severely weaken the connections between past- and future-oriented mental states and turn the psychological grounds for personal identity and prudential concern for our future selves. In addition, the collective effects of longer lives might lower the quality of life for all people. These two problems provide reasons against genetic manipulation of cells to alter the length of the human life span.

Evolutionary Models for Simple Biosystems

NASA Astrophysics Data System (ADS)

Bagnoli, Franco

The concept of evolutionary development of structures constituted a real revolution in biology: it was possible to understand how the very complex structures of life can arise in an out-of-equilibrium system. The investigation of such systems has shown that indeed, systems under a flux of energy or matter can self-organize into complex patterns, think for instance to Rayleigh-Bernard convection, Liesegang rings, patterns formed by granular systems under shear. Following this line, one could characterize life as a state of matter, characterized by the slow, continuous process that we call evolution. In this paper we try to identify the organizational level of life, that spans several orders of magnitude from the elementary constituents to whole ecosystems. Although similar structures can be found in other contexts like ideas (memes) in neural systems and self-replicating elements (computer viruses, worms, etc.) in computer systems, we shall concentrate on biological evolutionary structure, and try to put into evidence the role and the emergence of network structure in such systems.

Life-Span Extension in Mice by Preweaning Food Restriction and by Methionine Restriction in Middle Age

PubMed Central

Sun, Liou; Sadighi Akha, Amir A.; Miller, Richard A.

2009-01-01

Life span can be extended in rodents by restricting food availability (caloric restriction [CR]) or by providing food low in methionine (Meth-R). Here, we show that a period of food restriction limited to the first 20 days of life, via a 50% enlargement of litter size, shows extended median and maximal life span relative to mice from normal sized litters and that a Meth-R diet initiated at 12 months of age also significantly increases longevity. Furthermore, mice exposed to a CR diet show changes in liver messenger RNA patterns, in phosphorylation of Erk, Jnk2, and p38 kinases, and in phosphorylation of mammalian target of rapamycin and its substrate 4EBP1, HE-binding protein 1 that are not observed in liver from age-matched Meth-R mice. These results introduce new protocols that can increase maximal life span and suggest that the spectrum of metabolic changes induced by low-calorie and low-methionine diets may differ in instructive ways. PMID:19414512

Bedrock composition regulates mountain ecosystems and landscape evolution

PubMed Central

Hahm, W. Jesse; Riebe, Clifford S.; Lukens, Claire E.; Araki, Sayaka

2014-01-01

Earth’s land surface teems with life. Although the distribution of ecosystems is largely explained by temperature and precipitation, vegetation can vary markedly with little variation in climate. Here we explore the role of bedrock in governing the distribution of forest cover across the Sierra Nevada Batholith, California. Our sites span a narrow range of elevations and thus a narrow range in climate. However, land cover varies from Giant Sequoia (Sequoiadendron giganteum), the largest trees on Earth, to vegetation-free swaths that are visible from space. Meanwhile, underlying bedrock spans nearly the entire compositional range of granitic bedrock in the western North American cordillera. We explored connections between lithology and vegetation using measurements of bedrock geochemistry and forest productivity. Tree-canopy cover, a proxy for forest productivity, varies by more than an order of magnitude across our sites, changing abruptly at mapped contacts between plutons and correlating with bedrock concentrations of major and minor elements, including the plant-essential nutrient phosphorus. Nutrient-poor areas that lack vegetation and soil are eroding more than two times slower on average than surrounding, more nutrient-rich, soil-mantled bedrock. This suggests that bedrock geochemistry can influence landscape evolution through an intrinsic limitation on primary productivity. Our results are consistent with widespread bottom-up lithologic control on the distribution and diversity of vegetation in mountainous terrain. PMID:24516144

The Writing Process: Effects of Life-Span Development on Imaging.

ERIC Educational Resources Information Center

Shock, Diane Hahn

A qualitative study focused on incubation and illumination within the act of writing to determine if life-span development affects image production during these creative, cognitive acts. Sixteen subjects of both sexes from four age groups represented major developmental stages in the life cycle. The research design provided two 90-minute sessions…

Personal Goals and Well-Being: How Do Young People Navigate Their Lives?

ERIC Educational Resources Information Center

Salmela-Aro, Katariina

2010-01-01

This chapter examines development through different life transitions, such as educational transitions and transition to parenthood during adolescence to adulthood in the context of the life-span model of personal goals. According to the life-span model of motivation, four key mechanisms--channeling, choice, co-regulation, and compensation--play a…

A CRTCal link between energy and life span.

PubMed

Brunet, Anne

2011-04-06

Cutting down calories prolongs life, but how this works remains largely unknown. A recent study in Nature (Mair et al., 2011) shows that life span extension triggered by the energy-sensing protein kinase AMPK is mediated by an evolutionarily conserved transcriptional circuit involving CRTC-1 and CREB. Copyright © 2011 Elsevier Inc. All rights reserved.

Visual Search Across the Life Span

ERIC Educational Resources Information Center

Hommel, Bernhard; Li, Karen Z. H.; Li, Shu-Chen

2004-01-01

Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in…

Improvement/Maintenance and Reorientation as Central Features of Coping with Major Life Change and Loss: Contributions of Three Life-Span Theories

ERIC Educational Resources Information Center

Boerner, Kathrin; Jopp, Daniela

2007-01-01

This article focuses on the common and unique contributions of three major life-span theories in addressing improvement/maintenance and reorientation, which represent central processes of coping with major life change and loss. For this purpose, we review and compare the dual-process model of assimilative and accommodative coping, the model of…

The Theory of Relativity: A Metatheory for Development?

ERIC Educational Resources Information Center

Sinnott, Jan Dynda

1981-01-01

Reviews relativity theory in physics to derive a relativistic metatheory applicable to life span developmental psychology. The discussion points out ways in which relativistic thinking might enhance understanding of life span development and epistemology. (Author/DB)

The primacy of primary control is a human universal: a reply to Gould's (1999) critique of the life-span theory of control.

PubMed

Heckhausen, J; Schulz, R

1999-07-01

This reply to S. J. Gould's (1999) critique of J. Heckhausen and R. Schulz's (1995) life-span theory of control addresses four issues: (1) the universal claim that primary control holds functional primacy over secondary control, (2) the status of secondary control as a confederate to primary control, (3) empirical evidence and paradigms for investigating universality and cultural variations, and (4) the capacity of the human control system to manage both gains and losses in control throughout the life span and aging-related decline in particular. Theoretical perspectives and empirical evidence from evolutionary, comparative, developmental, and cultural psychology are presented to support the authors' view that primary control striving holds functional primacy throughout the life span and across cultural and historical settings. Recommendations for empirically investigating the variations in the way primary control striving is expressed in different cultures are outlined.

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres

NASA Technical Reports Server (NTRS)

Kloek, G.; Winkle, L.

1979-01-01

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

Life-span extension by a metacaspase in the yeast Saccharomyces cerevisiae.

PubMed

Hill, Sandra Malmgren; Hao, Xinxin; Liu, Beidong; Nyström, Thomas

2014-06-20

Single-cell species harbor ancestral structural homologs of caspase proteases, although the evolutionary benefit of such apoptosis-related proteins in unicellular organisms is unclear. Here, we found that the yeast metacaspase Mca1 is recruited to the insoluble protein deposit (IPOD) and juxtanuclear quality-control compartment (JUNQ) during aging and proteostatic stress. Elevating MCA1 expression counteracted accumulation of unfolded proteins and aggregates and extended life span in a heat shock protein Hsp104 disaggregase- and proteasome-dependent manner. Consistent with a role in protein quality control, genetic interaction analysis revealed that MCA1 buffers against deficiencies in the Hsp40 chaperone YDJ1 in a caspase cysteine-dependent manner. Life-span extension and aggregate management by Mca1 was only partly dependent on its conserved catalytic cysteine, which suggests that Mca1 harbors both caspase-dependent and independent functions related to life-span control. Copyright © 2014, American Association for the Advancement of Science.

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres.

PubMed

Kloek, G; Winkle, L

1979-04-01

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

What makes a planet habitable, and how to search for habitable planets in other solar systems.

PubMed

Papagiannis, M D

1992-06-01

The availability of liquid water is the most important factor that makes a planet habitable, because water is a very effective polar molecule and hence an excellent solvent and facilitator for the complex chemistry of life. Its presence presupposes a planet with a significant mass that guarantees the presence of a substantial atmosphere, and a reasonable spinning rate to avoid overheating. It also implies that the planet is at moderate distances from its central star, a range that is called the Ecosphere or the Habitable Zone. Since the evolution of life to high intelligence seems to take billions of years, it requires also that the central star must be neither too massive, that will produce a lot of lethal UV radiation and will have too short a life-span to allow life to evolve, nor of very small mass which will be producing too feeble a radiation to sustain life. The detection of free Oxygen in the atmosphere of a planet is a very strong evidence for the presence of life, because Oxygen is highly reactive and would rapidly disappear by combining with other elements, unless it is continuously replenished by life as the by-product of the process of photosynthesis that builds food for life (sugars) from CO2 and H2O.

Nutritional Control of Chronological Aging and Heterochromatin in Saccharomyces cerevisiae.

PubMed

McCleary, David F; Rine, Jasper

2017-03-01

Calorie restriction extends life span in organisms as diverse as yeast and mammals through incompletely understood mechanisms.The role of NAD + -dependent deacetylases known as Sirtuins in this process, particularly in the yeast Saccharomyces cerevisiae , is controversial. We measured chronological life span of wild-type and sir2 Δ strains over a higher glucose range than typically used for studying yeast calorie restriction. sir2 Δ extended life span in high glucose complete minimal medium and had little effect in low glucose medium, revealing a partial role for Sir2 in the calorie-restriction response under these conditions. Experiments performed on cells grown in rich medium with a newly developed genetic strategy revealed that sir2 Δ shortened life span in low glucose while having little effect in high glucose, again revealing a partial role for Sir2 In complete minimal media, Sir2 shortened life span as glucose levels increased; whereas in rich media, Sir2 extended life span as glucose levels decreased. Using a genetic strategy to measure the strength of gene silencing at HML , we determined increasing glucose stabilized Sir2-based silencing during growth on complete minimal media. Conversely, increasing glucose destabilized Sir-based silencing during growth on rich media, specifically during late cell divisions. In rich medium, silencing was far less stable in high glucose than in low glucose during stationary phase. Therefore, Sir2 was involved in a response to nutrient cues including glucose that regulates chronological aging, possibly through Sir2-dependent modification of chromatin or deacetylation of a nonhistone protein. Copyright © 2017 by the Genetics Society of America.

Deleting the 14-3-3 protein Bmh1 extends life span in Saccharomyces cerevisiae by increasing stress response.

PubMed

Wang, Chen; Skinner, Craig; Easlon, Erin; Lin, Su-Ju

2009-12-01

Enhanced stress response has been suggested to promote longevity in many species. Calorie restriction (CR) and conserved nutrient-sensing target of rapamycin (TOR) and protein kinase A (PKA) pathways have also been suggested to extend life span by increasing stress response, which protects cells from age-dependent accumulation of oxidative damages. Here we show that deleting the yeast 14-3-3 protein, Bmh1, extends chronological life span (CLS) by activating the stress response. 14-3-3 proteins are highly conserved chaperone-like proteins that play important roles in many cellular processes. bmh1Delta-induced heat resistance and CLS extension require the general stress-response transcription factors Msn2, Msn4, and Rim15. The bmh1Delta mutant also displays a decreased reactive oxygen species level and increased heat-shock-element-driven transcription activity. We also show that BMH1 genetically interacts with CR and conserved nutrient-sensing TOR- and PKA-signaling pathways to regulate life span. Interestingly, the level of phosphorylated Ser238 on Bmh1 increases during chronological aging, which is delayed by CR or by reduced TOR activities. In addition, we demonstrate that PKA can directly phosphorylate Ser238 on Bmh1. The status of Bmh1 phosphorylation is therefore likely to play important roles in life-span regulation. Together, our studies suggest that phosphorylated Bmh1 may cause inhibitory effects on downstream longevity factors, including stress-response proteins. Deleting Bmh1 may eliminate the inhibitory effects of Bmh1 on these longevity factors and therefore extends life span.

Selection for longevity confers resistance to low-temperature stress in Drosophila melanogaster.

PubMed

Luckinbill, L S

1998-03-01

One theory of the evolution of longevity says that improvement in life span is dependent on an increased ability to resist environmental stresses of all kind. Selective breeding of Drosophila melanogaster populations for longevity has demonstrably increased life span and also altered a number of other traits, such as resistance to starvation, desiccation, and ethanol fumes, and the ability to sustain longer flight. While the exact physiologic basis of some of these traits is not yet fully understood, at least some are known to derive from the properties of metabolic substrates of glycolysis. Improvement in those characters can depend partially, therefore, on altered stores of metabolites created from glycogen. Based on the known general relationship of some traits and the suspected basis in metabolism of others, we examine the possibility here that increased life span is accompanied by other traits that also confer physiologic resistance to stress. Specifically, we test the prediction that long-lived populations of fruit flies should be more resistant to low (prefreezing) and freezing temperature extremes. Both selected and control populations were found to be susceptible to prefreezing (1.5 degrees C) and freezing temperatures (0 degree C) here, but adults and pupae of the long-lived populations generally survived better in both situations, and at all durations of exposure. The resistance of individuals improved with acclimatization, but was superior in the long-lived populations whether thermal decline was rapid or stepwise. Cold resistant, long-lived populations also had significantly higher in vitro levels of glycerol, a cryoprotectant metabolite produced from glycogen. However, while adults and pupae of long-lived stocks were more resistant to cold, larvae of those stocks were more sensitive and survived relatively poorly at every length of exposure and acclimation. This surprising result implies that larvae maintain lower levels of cryoprotectant substances. Upon becoming pupae, however, stage-specific capabilities for environmental resistance and long life emerge. This conclusion agrees with a prior study of these stocks indicating that the uptake and use of nutrients in developing larvae are restricted in long-lived populations.

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups.

PubMed

Reich, Peter B; Walters, Michael B; Ellsworth, David S; Vose, James M; Volin, John C; Gresham, Charles; Bowman, William D

1998-05-01

Based on prior evidence of coordinated multiple leaf trait scaling, we hypothesized that variation among species in leaf dark respiration rate (R d ) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (A max ). However, it is not known whether such scaling, if it exists, is similar among disparate biomes and plant functional types. We tested this idea by examining the interspecific relationships between R d measured at a standard temperature and leaf life-span, N, SLA and A max for 69 species from four functional groups (forbs, broad-leafed trees and shrubs, and needle-leafed conifers) in six biomes traversing the Americas: alpine tundra/subalpine forest, Colorado; cold temperate forest/grassland, Wisconsin; cool temperate forest, North Carolina; desert/shrubland, New Mexico; subtropical forest, South Carolina; and tropical rain forest, Amazonas, Venezuela. Area-based R d was positively related to area-based leaf N within functional groups and for all species pooled, but not when comparing among species within any site. At all sites, mass-based R d (R d-mass ) decreased sharply with increasing leaf life-span and was positively related to SLA and mass-based A max and leaf N (leaf N mass ). These intra-biome relationships were similar in shape and slope among sites, where in each case we compared species belonging to different plant functional groups. Significant R d-mass -N mass relationships were observed in all functional groups (pooled across sites), but the relationships differed, with higher R d at any given leaf N in functional groups (such as forbs) with higher SLA and shorter leaf life-span. Regardless of biome or functional group, R d-mass was well predicted by all combinations of leaf life-span, N mass and/or SLA (r 2 ≥ 0.79, P < 0.0001). At any given SLA, R d-mass rises with increasing N mass and/or decreasing leaf life-span; and at any level of N mass , R d-mass rises with increasing SLA and/or decreasing leaf life-span. The relationships between R d and leaf traits observed in this study support the idea of a global set of predictable interrelationships between key leaf morphological, chemical and metabolic traits.

Antioxidants, metabolic rate and aging in Drosophila

NASA Technical Reports Server (NTRS)

Miquel, J.; Fleming, J.; Economos, A. C.

1982-01-01

The metabolic rate-of-living theory of aging was investigated by determining the effect of several life-prolonging antioxidants on the metabolic rate and life span of Drosophila. The respiration rate of groups of continuously agitated flies was determined in a Gilson respirometer. Vitamin E, 2,4-dinitrophenol, nordihydroguaiaretic acid, and thiazolidine carboxylic acid were employed as antioxidants. Results show that all of these antioxidants reduced the oxygen consumption rate and increased the mean life span, and a significant negative linear correlation was found between the mean life span and the metabolic rate. It is concluded that these findings indicate that some antioxidants may inhibit respiration rate in addition to their protective effect against free radical-induced cellular damage.

Life-span extension by dietary restriction is mediated by NLP-7 signaling and coelomocyte endocytosis in C. elegans.

PubMed

Park, Sang-Kyu; Link, Christopher D; Johnson, Thomas E

2010-02-01

Recent studies have shown that the rate of aging can be modulated by diverse interventions. Dietary restriction is the most widely used intervention to promote longevity; however, the mechanisms underlying the effect of dietary restriction remain elusive. In a previous study, we identified two novel genes, nlp-7 and cup-4, required for normal longevity in Caenorhabditis elegans. nlp-7 is one of a set of neuropeptide-like protein genes; cup-4 encodes an ion-channel involved in endocytosis by coelomocytes. Here, we assess whether nlp-7 and cup-4 mediate longevity increases by dietary restriction. RNAi of nlp-7 or cup-4 significantly reduces the life span of the eat-2 mutant, a genetic model of dietary restriction, but has no effect on the life span of long-lived mutants resulting from reduced insulin/IGF-1 signaling or dysfunction of the mitochondrial electron transport chain. The life-span extension observed in wild-type N2 worms by dietary restriction using bacterial dilution is prevented significantly in nlp-7 and cup-4 mutants. RNAi knockdown of genes encoding candidate receptors of NLP-7 and genes involved in endocytosis by coelomocytes also specifically shorten the life span of the eat-2 mutant. We conclude that two novel pathways, NLP-7 signaling and endocytosis by coelomocytes, are required for life extension under dietary restriction in C. elegans.

The control processes and subjective well-being of Chinese teachers: evidence of convergence with and divergence from the key propositions of the motivational theory of life-span development

PubMed Central

Wong, Wan-chi; Li, Yin; Sun, Xiaoyan; Xu, Huanu

2014-01-01

An analytical review of the motivational theory of life-span development reveals that this theory has undergone a series of elegant theoretical integrations. Its claim to universality nonetheless brings forth unresolved controversies. With the purpose of scrutinizing the key propositions of this theory, an empirical study was designed to examine the control processes and subjective well-being of Chinese teachers (N = 637). The OPS-Scales (Optimization in Primary and Secondary Control Scales) for the Domain of Teaching were constructed to assess patterns of control processes. Three facets of subjective well-being were investigated with the Positive and Negative Affect Schedule, the Life Satisfaction Scale, and the Subjective Vitality Scale. The results revealed certain aspects of alignment with and certain divergences from the key propositions of the motivational theory of life-span development. Neither “primacy of primary control” nor “primacy of secondary control” was clearly supported. Notably, using different criteria for subjective well-being yielded different subtypes of primary and secondary control as predictors. The hypothesized life-span trajectories of primary and secondary control received limited support. To advance the theory in this area, we recommend incorporating Lakatos' ideas about sophisticated falsification by specifying the hard core of the motivational theory of life-span development and articulating new auxiliary hypotheses. PMID:24904483

The emergence of longevous populations

PubMed Central

Colchero, Fernando; Rau, Roland; Barthold, Julia A.; Conde, Dalia A.; Lenart, Adam; Nemeth, Laszlo; Scheuerlein, Alexander; Schoeley, Jonas; Torres, Catalina; Zarulli, Virginia; Altmann, Jeanne; Brockman, Diane K.; Bronikowski, Anne M.; Fedigan, Linda M.; Pusey, Anne E.; Stoinski, Tara S.; Strier, Karen B.; Baudisch, Annette; Alberts, Susan C.; Vaupel, James W.

2016-01-01

The human lifespan has traversed a long evolutionary and historical path, from short-lived primate ancestors to contemporary Japan, Sweden, and other longevity frontrunners. Analyzing this trajectory is crucial for understanding biological and sociocultural processes that determine the span of life. Here we reveal a fundamental regularity. Two straight lines describe the joint rise of life expectancy and lifespan equality: one for primates and the second one over the full range of human experience from average lifespans as low as 2 y during mortality crises to more than 87 y for Japanese women today. Across the primate order and across human populations, the lives of females tend to be longer and less variable than the lives of males, suggesting deep evolutionary roots to the male disadvantage. Our findings cast fresh light on primate evolution and human history, opening directions for research on inequality, sociality, and aging. PMID:27872299

Foraging across the life span: is there a reduction in exploration with aging?

PubMed Central

Mata, Rui; Wilke, Andreas; Czienskowski, Uwe

2013-01-01

Does foraging change across the life span, and in particular, with aging? We report data from two foraging tasks used to investigate age differences in search in external environments as well as internal search in memory. Overall, the evidence suggests that foraging behavior may undergo significant changes across the life span across internal and external search. In particular, we find evidence of a trend toward reduced exploration with increased age. We discuss these findings in light of theories that postulate a link between aging and reductions in novelty seeking and exploratory behavior. PMID:23616741

Evolution and selection of river networks: Statics, dynamics, and complexity

PubMed Central

Rinaldo, Andrea; Rigon, Riccardo; Banavar, Jayanth R.; Maritan, Amos; Rodriguez-Iturbe, Ignacio

2014-01-01

Moving from the exact result that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, we review the static properties and the dynamic origins of the scale-invariant structure of optimal river patterns. Optimal channel networks (OCNs) are feasible optimal configurations of a spanning network mimicking landscape evolution and network selection through imperfect searches for dynamically accessible states. OCNs are spanning loopless configurations, however, only under precise physical requirements that arise under the constraints imposed by river dynamics—every spanning tree is exactly a local minimum of total energy dissipation. It is remarkable that dynamically accessible configurations, the local optima, stabilize into diverse metastable forms that are nevertheless characterized by universal statistical features. Such universal features explain very well the statistics of, and the linkages among, the scaling features measured for fluvial landforms across a broad range of scales regardless of geology, exposed lithology, vegetation, or climate, and differ significantly from those of the ground state, known exactly. Results are provided on the emergence of criticality through adaptative evolution and on the yet-unexplored range of applications of the OCN concept. PMID:24550264

Lateral Gene Transfer Dynamics in the Ancient Bacterial Genus Streptomyces

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Bradon R.; Currie, Cameron R.

Lateral gene transfer (LGT) profoundly shapes the evolution of bacterial lineages. LGT across disparate phylogenetic groups and genome content diversity between related organisms suggest a model of bacterial evolution that views LGT as rampant and promiscuous. It has even driven the argument that species concepts and tree-based phylogenetics cannot be applied to bacteria. For this paper, we show that acquisition and retention of genes through LGT are surprisingly rare in the ubiquitous and biomedically important bacterial genusStreptomyces. Using a molecular clock, we estimate that theStreptomycesbacteria are ~380 million years old, indicating that this bacterial genus is as ancient as landmore » vertebrates. Calibrating LGT rate to this geologic time span, we find that on average only 10 genes per million years were acquired and subsequently maintained. Over that same time span,Streptomycesaccumulated thousands of point mutations. By explicitly incorporating evolutionary timescale into our analyses, we provide a dramatically different view on the dynamics of LGT and its impact on bacterial evolution.Tree-based phylogenetics and the use of species as units of diversity lie at the foundation of modern biology. In bacteria, these pillars of evolutionary theory have been called into question due to the observation of thousands of lateral gene transfer (LGT) events within and between lineages. Here, we show that acquisition and retention of genes through LGT are exceedingly rare in the bacterial genusStreptomyces, with merely one gene acquired inStreptomyceslineages every 100,000 years. These findings stand in contrast to the current assumption of rampant genetic exchange, which has become the dominant hypothesis used to explain bacterial diversity. Our results support a more nuanced understanding of genetic exchange, with LGT impacting evolution over short timescales but playing a significant role over long timescales. Deeper understanding of LGT provides new insight into the evolutionary history of life on Earth, as the vast majority of this history is microbial.« less

Lateral Gene Transfer Dynamics in the Ancient Bacterial Genus Streptomyces

DOE PAGES

McDonald, Bradon R.; Currie, Cameron R.

2017-06-06

Lateral gene transfer (LGT) profoundly shapes the evolution of bacterial lineages. LGT across disparate phylogenetic groups and genome content diversity between related organisms suggest a model of bacterial evolution that views LGT as rampant and promiscuous. It has even driven the argument that species concepts and tree-based phylogenetics cannot be applied to bacteria. For this paper, we show that acquisition and retention of genes through LGT are surprisingly rare in the ubiquitous and biomedically important bacterial genusStreptomyces. Using a molecular clock, we estimate that theStreptomycesbacteria are ~380 million years old, indicating that this bacterial genus is as ancient as landmore » vertebrates. Calibrating LGT rate to this geologic time span, we find that on average only 10 genes per million years were acquired and subsequently maintained. Over that same time span,Streptomycesaccumulated thousands of point mutations. By explicitly incorporating evolutionary timescale into our analyses, we provide a dramatically different view on the dynamics of LGT and its impact on bacterial evolution.Tree-based phylogenetics and the use of species as units of diversity lie at the foundation of modern biology. In bacteria, these pillars of evolutionary theory have been called into question due to the observation of thousands of lateral gene transfer (LGT) events within and between lineages. Here, we show that acquisition and retention of genes through LGT are exceedingly rare in the bacterial genusStreptomyces, with merely one gene acquired inStreptomyceslineages every 100,000 years. These findings stand in contrast to the current assumption of rampant genetic exchange, which has become the dominant hypothesis used to explain bacterial diversity. Our results support a more nuanced understanding of genetic exchange, with LGT impacting evolution over short timescales but playing a significant role over long timescales. Deeper understanding of LGT provides new insight into the evolutionary history of life on Earth, as the vast majority of this history is microbial.« less

Lateral Gene Transfer Dynamics in the Ancient Bacterial Genus Streptomyces.

PubMed

McDonald, Bradon R; Currie, Cameron R

2017-06-06

Lateral gene transfer (LGT) profoundly shapes the evolution of bacterial lineages. LGT across disparate phylogenetic groups and genome content diversity between related organisms suggest a model of bacterial evolution that views LGT as rampant and promiscuous. It has even driven the argument that species concepts and tree-based phylogenetics cannot be applied to bacteria. Here, we show that acquisition and retention of genes through LGT are surprisingly rare in the ubiquitous and biomedically important bacterial genus Streptomyces Using a molecular clock, we estimate that the Streptomyces bacteria are ~380 million years old, indicating that this bacterial genus is as ancient as land vertebrates. Calibrating LGT rate to this geologic time span, we find that on average only 10 genes per million years were acquired and subsequently maintained. Over that same time span, Streptomyces accumulated thousands of point mutations. By explicitly incorporating evolutionary timescale into our analyses, we provide a dramatically different view on the dynamics of LGT and its impact on bacterial evolution. IMPORTANCE Tree-based phylogenetics and the use of species as units of diversity lie at the foundation of modern biology. In bacteria, these pillars of evolutionary theory have been called into question due to the observation of thousands of lateral gene transfer (LGT) events within and between lineages. Here, we show that acquisition and retention of genes through LGT are exceedingly rare in the bacterial genus Streptomyces , with merely one gene acquired in Streptomyces lineages every 100,000 years. These findings stand in contrast to the current assumption of rampant genetic exchange, which has become the dominant hypothesis used to explain bacterial diversity. Our results support a more nuanced understanding of genetic exchange, with LGT impacting evolution over short timescales but playing a significant role over long timescales. Deeper understanding of LGT provides new insight into the evolutionary history of life on Earth, as the vast majority of this history is microbial. Copyright © 2017 McDonald and Currie.

Corrigendum: Childhood Adversity, Self-Esteem, and Diurnal Cortisol Profiles Across the Life Span.

PubMed

2018-01-01

Original article: Zilioli, S., Slatcher, R. B., Chi, P., Li, X., Zhao, J., & Zhao, G. (2016). Childhood adversity, self-esteem, and diurnal cortisol profiles across the life span. Psychological Science, 27, 1249-1265. doi:10.1177/0956797616658287.

Sibling Communication Functions across the Life-Span.

ERIC Educational Resources Information Center

Myers, Scott A.; Smith, Ronda L.; Sonnier, Michelle F.

An investigation examined whether perceived use of sibling functional communication skills differed across the life-span. Participants were recruited through university students enrolled in an introductory communication course at a southern university. All students received extra credit for recruiting two participants. Potential participants were…

Royal Darwinian Demons: Enforced Changes in Reproductive Efforts Do Not Affect the Life Expectancy of Ant Queens.

PubMed

Schrempf, Alexandra; Giehr, Julia; Röhrl, Ramona; Steigleder, Sarah; Heinze, Jürgen

2017-04-01

One of the central tenets of life-history theory is that organisms cannot simultaneously maximize all fitness components. This results in the fundamental trade-off between reproduction and life span known from numerous animals, including humans. Social insects are a well-known exception to this rule: reproductive queens outlive nonreproductive workers. Here, we take a step forward and show that under identical social and environmental conditions the fecundity-longevity trade-off is absent also within the queen caste. A change in reproduction did not alter life expectancy, and even a strong enforced increase in reproductive efforts did not reduce residual life span. Generally, egg-laying rate and life span were positively correlated. Queens of perennial social insects thus seem to maximize at the same time two fitness parameters that are normally negatively correlated. Even though they are not immortal, they best approach a hypothetical "Darwinian demon" in the animal kingdom.

Heart rate reduction and longevity in mice.

PubMed

Gent, Sabine; Kleinbongard, Petra; Dammann, Philip; Neuhäuser, Markus; Heusch, Gerd

2015-03-01

Heart rate correlates inversely with life span across all species, including humans. In patients with cardiovascular disease, higher heart rate is associated with increased mortality, and such patients benefit from pharmacological heart rate reduction. However, cause-and-effect relationships between heart rate and longevity, notably in healthy individuals, are not established. We therefore prospectively studied the effects of a life-long pharmacological heart rate reduction on longevity in mice. We hypothesized, that the total number of cardiac cycles is constant, and that a 15% heart rate reduction might translate into a 15% increase in life span. C57BL6/J mice received either placebo or ivabradine at a dose of 50 mg/kg/day in drinking water from 12 weeks to death. Heart rate and body weight were monitored. Autopsy was performed on all non-autolytic cadavers, and parenchymal organs were evaluated macroscopically. Ivabradine reduced heart rate by 14% (median, interquartile range 12-15%) throughout life, and median life span was increased by 6.2% (p = 0.01). Body weight and macroscopic findings were not different between placebo and ivabradine. Life span was not increased to the same extent as heart rate was reduced, but nevertheless significantly prolonged by 6.2%.

A cost–benefit analysis of acclimation to low irradiance in tropical rainforest tree seedlings: leaf life span and payback time for leaf deployment

PubMed Central

Coste, Sabrina; Roggy, Jean-Christophe; Schimann, Heidy; Epron, Daniel; Dreyer, Erwin

2011-01-01

The maintenance in the long run of a positive carbon balance under very low irradiance is a prerequisite for survival of tree seedlings below the canopy or in small gaps in a tropical rainforest. To provide a quantitative basis for this assumption, experiments were carried out to determine whether construction cost (CC) and payback time for leaves and support structures, as well as leaf life span (i) differ among species and (ii) display an irradiance-elicited plasticity. Experiments were also conducted to determine whether leaf life span correlates to CC and payback time and is close to the optimal longevity derived from an optimization model. Saplings from 13 tropical tree species were grown under three levels of irradiance. Specific-CC was computed, as well as CC scaled to leaf area at the metamer level. Photosynthesis was recorded over the leaf life span. Payback time was derived from CC and a simple photosynthesis model. Specific-CC displayed only little interspecific variability and irradiance-elicited plasticity, in contrast to CC scaled to leaf area. Leaf life span ranged from 4 months to >26 months among species, and was longest in seedlings grown under lowest irradiance. It was always much longer than payback time, even under the lowest irradiance. Leaves were shed when their photosynthesis had reached very low values, in contrast to what was predicted by an optimality model. The species ranking for the different traits was stable across irradiance treatments. The two pioneer species always displayed the smallest CC, leaf life span, and payback time. All species displayed a similar large irradiance-elicited plasticity. PMID:21511904

KIRA1 and ORESARA1 terminate flower receptivity by promoting cell death in the stigma of Arabidopsis.

PubMed

Gao, Zhen; Daneva, Anna; Salanenka, Yuliya; Van Durme, Matthias; Huysmans, Marlies; Lin, Zongcheng; De Winter, Freya; Vanneste, Steffen; Karimi, Mansour; Van de Velde, Jan; Vandepoele, Klaas; Van de Walle, Davy; Dewettinck, Koen; Lambrecht, Bart N; Nowack, Moritz K

2018-05-28

Flowers have a species-specific functional life span that determines the time window in which pollination, fertilization and seed set can occur. The stigma tissue plays a key role in flower receptivity by intercepting pollen and initiating pollen tube growth toward the ovary. In this article, we show that a developmentally controlled cell death programme terminates the functional life span of stigma cells in Arabidopsis. We identified the leaf senescence regulator ORESARA1 (also known as ANAC092) and the previously uncharacterized KIRA1 (also known as ANAC074) as partially redundant transcription factors that modulate stigma longevity by controlling the expression of programmed cell death-associated genes. KIRA1 expression is sufficient to induce cell death and terminate floral receptivity, whereas lack of both KIRA1 and ORESARA1 substantially increases stigma life span. Surprisingly, the extension of stigma longevity is accompanied by only a moderate extension of flower receptivity, suggesting that additional processes participate in the control of the flower's receptive life span.

Getting together: Social contact frequency across the life span.

PubMed

Sander, Julia; Schupp, Jürgen; Richter, David

2017-08-01

Frequent social interactions are strongly linked to positive affect, longevity, and good health. Although there has been extensive research on changes in the size of social networks over time, little attention has been given to the development of contact frequency across the life span. In this cohort-sequential longitudinal study, we examined intraindividual changes in the frequency of social contact with family and nonfamily members, and potential moderators of these changes. The data come from the 1998, 2003, 2008, and 2013 waves of the German Socio-Economic Panel (SOEP) study (N = 36,716; age range: 17-85 years). Using latent growth curve analysis, we found that the frequency of in-person contact with family members remained relatively stable across the life span. In contrast, the frequency of visits to and from nonfamily members (neighbors, friends, and acquaintances) declined following a cubic trajectory and dropped below the frequency of family visits when respondents were in their mid-30s. Relationship status and gender had a slight effect on both of these relationship trajectories. Subjective current health status and employment status influenced the life span trajectory of nonfamily social contact only. Changes of residence and the birth of a child, both of which constitute major turning points in the life course, did not affect the life span trajectory of either family or nonfamily in-person contact. The findings are discussed here in the context of earlier findings and in relation to socioemotional selectivity and social convoy theory and the evolutionary life history approach. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Evolution of static allometries: adaptive change in allometric slopes of eye span in stalk-eyed flies.

PubMed

Voje, Kjetil L; Hansen, Thomas F

2013-02-01

Julian Huxley showed that within-species (static) allometric (power-law) relations can arise from proportional growth regulation with the exponent in the power law equaling the factor of proportionality. Allometric exponents may therefore be hard to change and act as constraints on the independent evolution of traits. In apparent contradiction to this, many empirical studies have concluded that static allometries are evolvable. Many of these studies have been based, however, on a broad definition of allometry that includes any monotonic shape change with size, and do not falsify the hypothesis of constrained narrow-sense allometry. Here, we present the first phylogenetic comparative study of narrow-sense allometric exponents based on a reanalysis of data on eye span and body size in stalk-eyed flies (Diopsidae). Consistent with a role in sexual selection, we found strong evidence that male slopes were tracking "optima" based on sexual dimorphism and relative male trait size. This tracking was slow, however, with estimated times of 2-3 million years for adaptation to exceed ancestral influence on the trait. Our results are therefore consistent with adaptive evolution on million-year time scales, but cannot rule out that static allometry may act as a constraint on eye-span adaptation at shorter time scales. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Effect of habitat preference on frond life span in three Cyathea tree ferns

NASA Astrophysics Data System (ADS)

Chiu, Tzu Yun; Wang, Hsiang Hua; Lun Kuo, Yao; Kume, Tomonori

2013-04-01

It has been reported that plants living in various geographical areas had different physiological forms, as factors of microenvironment have strong impacts on physiological characters. However, the physiological characters of fronds have been scarcely reported in ferns. In this study, we investigated physiological differences in response to the habitat preference in the three tree ferns in northeast Taiwan, Cyathea lepifera, C. spinulosa, and C. podophylla, prefer to open site, edge of forest, and interior forest, respectively. The canopy openness above the individuals of C. lepifera, C. spinulosa and C. podophylla were 29.2 ± 14.10 , 7.0 ± 3.07 and 5.0 ± 2.24 %, respectively. Among three species, C. podophylla had the longest frond life span (13.0 ± 4.12 months) than the two others (C. lepifera (6.8 ± 1.29 months) and C. spinulosa (7.3 ±1.35 months). Our result supported the general patterns that shade intolerant species have a shorter leaf life span than shade tolerant species. The maximum net CO2 assimilation of C. lepifera, C. spinulosa and C. podophylla were 11.46 ± 1.34, 8.27 ± 0.69, and 6.34 ± 0.54 μmol CO2 m-2 s-1, respectively. As well, C. lepifera had the highest photosynthetic light saturation point (LSP), while C. podophylla had the lowest LSP among these three tree ferns. These suggested that C. lepifera could be more efficient for capturing and utilizing light resources under the larger canopy openness condition than the other two species. We also found that frond C : N ratio were positively correlated with frond life span among species. C. podophylla, with the longest frond life span, had the highest frond C : N ratio (22.17 ± 1.95), which was followed by C. spinulosa (18.58 ± 1.37) and C. lepifera (18.68 ± 2.63) with shorter frond life span. The results were consistent to the theory that the fronds and leaves of shade intolerant species have high photosynthetic abilities with low C : N ratio. Key words: Canopy openness, frond life span, tree fern, Cyathea, frond C : N ratio

Little evidence for intralocus sexual conflict over the optimal intake of nutrients for life span and reproduction in the black field cricket Teleogryllus commodus

PubMed Central

Rapkin, James; Archer, C. Ruth; Grant, Charles E.; Jensen, Kim; House, Clarissa M.; Wilson, Alastair J.; Hunt, John

2017-01-01

Abstract There is often large divergence in the effects of key nutrients on life span (LS) and reproduction in the sexes, yet nutrient intake is regulated in the same way in males and females given dietary choice. This suggests that the sexes are constrained from feeding to their sex‐specific nutritional optima for these traits. Here, we examine the potential for intralocus sexual conflict (IASC) over optimal protein and carbohydrate intake for LS and reproduction to constrain the evolution of sex‐specific nutrient regulation in the field cricket, Teleogryllus commodus. We show clear sex differences in the effects of protein and carbohydrate intake on LS and reproduction and strong positive genetic correlations between the sexes for the regulated intake of these nutrients. However, the between‐sex additive genetic covariance matrix had very little effect on the predicted evolutionary response of nutrient regulation in the sexes. Thus, IASC appears unlikely to act as an evolutionary constraint on sex‐specific nutrient regulation in T. commodus. This finding is supported by clear sexual dimorphism in the regulated intake of these nutrients under dietary choice. However, nutrient regulation did not coincide with the nutritional optima for LS or reproduction in either sex, suggesting that IASC is not completely resolved in T. commodus. PMID:28640400

Post-dauer life span of Caenorhabditis elegans dauer larvae can be modified by X-irradiation.

PubMed

Onodera, Akira; Yanase, Sumino; Ishii, Takamasa; Yasuda, Kayo; Miyazawa, Masaki; Hartman, Philip S; Ishii, Naoaki

2010-01-01

The time spent as a dauer larva does not affect adult life span in Caenorhabditis elegans, as if aging is suspended in this quiescent developmental stage. We now report that modest doses X-irradiation of dauer larvae increased their post-dauer longevity. Post-irradiation incubation of young dauer larvae did not modify this beneficial effect of radiation. Conversely, holding dauer larvae prior to irradiation rendered them refractory to this X-radiation-induced response. We present a model to explain these results. These experiments demonstrate that dauer larvae provide an excellent opportunity to study mechanisms by which X irradiation can extend life span.

Spontaneous locomotor activity and life span. A test of the rate of living theory in Drosophila melanogaster.

PubMed

Lints, F A; Le Bourg, E; Lints, C V

1984-01-01

The spontaneous locomotor activity and life span of approximately 600 individuals of both sexes and of three widely different genotypes of Drosophila melanogaster have been measured. Neither at the individual nor at the populational level could a significant correlation between spontaneous locomotor activity and life span be found. The results are discussed in relation with Pearl's [The rate of living, London University Press, London 1928] rate of living theory. That theory has been tested in relation with environmental temperature, oxygen consumption and activity. It is shown that the theory has received no definite confirmation until now.

Feminist Developmental Theory: Implications for Counseling.

ERIC Educational Resources Information Center

Wastell, Colin A.

1996-01-01

Discusses the importance of counseling guided by a life-span development model. Emphasizes that one popular theory should be modified by taking into account a broader understanding of life-span development in terms of commonalities and differences in male and female development. Examines implications with borderline personality disorder and…

Target of Rapamycin Signaling Regulates Metabolism, Growth, and Life Span in Arabidopsis[W][OA

PubMed Central

Ren, Maozhi; Venglat, Prakash; Qiu, Shuqing; Feng, Li; Cao, Yongguo; Wang, Edwin; Xiang, Daoquan; Wang, Jinghe; Alexander, Danny; Chalivendra, Subbaiah; Logan, David; Mattoo, Autar; Selvaraj, Gopalan; Datla, Raju

2012-01-01

Target of Rapamycin (TOR) is a major nutrition and energy sensor that regulates growth and life span in yeast and animals. In plants, growth and life span are intertwined not only with nutrient acquisition from the soil and nutrition generation via photosynthesis but also with their unique modes of development and differentiation. How TOR functions in these processes has not yet been determined. To gain further insights, rapamycin-sensitive transgenic Arabidopsis thaliana lines (BP12) expressing yeast FK506 Binding Protein12 were developed. Inhibition of TOR in BP12 plants by rapamycin resulted in slower overall root, leaf, and shoot growth and development leading to poor nutrient uptake and light energy utilization. Experimental limitation of nutrient availability and light energy supply in wild-type Arabidopsis produced phenotypes observed with TOR knockdown plants, indicating a link between TOR signaling and nutrition/light energy status. Genetic and physiological studies together with RNA sequencing and metabolite analysis of TOR-suppressed lines revealed that TOR regulates development and life span in Arabidopsis by restructuring cell growth, carbon and nitrogen metabolism, gene expression, and rRNA and protein synthesis. Gain- and loss-of-function Ribosomal Protein S6 (RPS6) mutants additionally show that TOR function involves RPS6-mediated nutrition and light-dependent growth and life span in Arabidopsis. PMID:23275579

Yeast MRX deletions have short chronological life span and more triacylglycerols.

PubMed

Kanagavijayan, Dhanabalan; Rajasekharan, Ram; Srinivasan, Malathi

2016-02-01

Saccharomyces cerevisiae is an excellent model organism for lipid research. Here, we have used yeast haploid RAdiation Damage (RAD) deletion strains to study life span and lipid storage patterns. RAD genes are mainly involved in DNA repair mechanism and hence, their deletions have resulted in shorter life span. Viable RAD mutants were screened for non-polar lipid content, and some of the mutants showed significantly high amounts of triacylglycerol (TAG) and steryl ester, besides short chronological life span. Among these, RAD50, MRE11 and XRS2 form a complex, MRX that is involved in homologous recombination that showed an increase in the amount of TAG. Microarray data of single MRX deletions revealed that besides DNA damage signature genes, lipid metabolism genes are also differentially expressed. Lipid biosynthetic genes (LPP1, SLC1) were upregulated and lipid hydrolytic gene (TGL3) was downregulated. We observed that rad50Δ, mre11Δ, xrs2Δ and mrxΔ strains have high number of lipid droplets (LDs) with fragmented mitochondria. These mutants have a short chronological life span compared to wild type. Aged wild-type cells also accumulated TAG with LDs of ∼2.0 μm in diameter. These results suggest that TAG accumulation and big size LDs could be possible markers for premature or normal aging. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Like cognitive function, decision making across the life span shows profound age-related changes.

PubMed

Tymula, Agnieszka; Rosenberg Belmaker, Lior A; Ruderman, Lital; Glimcher, Paul W; Levy, Ifat

2013-10-15

It has long been known that human cognitive function improves through young adulthood and then declines across the later life span. Here we examined how decision-making function changes across the life span by measuring risk and ambiguity attitudes in the gain and loss domains, as well as choice consistency, in an urban cohort ranging in age from 12 to 90 y. We identified several important age-related patterns in decision making under uncertainty: First, we found that healthy elders between the ages of 65 and 90 were strikingly inconsistent in their choices compared with younger subjects. Just as elders show profound declines in cognitive function, they also show profound declines in choice rationality compared with their younger peers. Second, we found that the widely documented phenomenon of ambiguity aversion is specific to the gain domain and does not occur in the loss domain, except for a slight effect in older adults. Finally, extending an earlier report by our group, we found that risk attitudes across the life span show an inverted U-shaped function; both elders and adolescents are more risk-averse than their midlife counterparts. Taken together, these characterizations of decision-making function across the life span in this urban cohort strengthen the conclusions of previous reports suggesting a profound impact of aging on cognitive function in this domain.

View of central lift span truss web of Tensaw River ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of central lift span truss web of Tensaw River Bridge, showing support girders for life house, looking east - Tensaw River Lift Bridge, Spanning Tensaw River at U.S. Highway 90, Mobile, Mobile County, AL

A rich diversity of opercle bone shape among teleost fishes

PubMed Central

Small, Clayton M.; Knope, Matthew L.

2017-01-01

The opercle is a prominent craniofacial bone supporting the gill cover in all bony fish and has been the subject of morphological, developmental, and genetic investigation. We surveyed the shapes of this bone among 110 families spanning the teleost tree and examined its pattern of occupancy in a principal component-based morphospace. Contrasting with expectations from the literature that suggest the local morphospace would be only sparsely occupied, we find primarily dense, broad filling of the morphological landscape, indicating rich diversity. Phylomorphospace plots suggest that dynamic evolution underlies the observed spatial patterning. Evolutionary transits through the morphospaces are sometimes long, and occur in a variety of directions. The trajectories seem to represent both evolutionary divergences and convergences, the latter supported by convevol analysis. We suggest that that this pattern of occupancy reflects the various adaptations of different groups of fishes, seemingly paralleling their diverse marine and freshwater ecologies and life histories. Opercle shape evolution within the acanthomorphs, spiny ray-finned fishes, appears to have been especially dynamic. PMID:29281662

FACT SHEET: EPA ISSUES UPDATED CANCER GUIDELINES AND SUPPLEMENTAL GUIDANCE ON RISKS FROM EARLY-LIFE EXPOSURE

EPA Science Inventory

March 29, 2005

FACT SHEET: Women's Spirituality across the Life Span: Implications for Counseling

ERIC Educational Resources Information Center

Briggs, Michele Kielty; Dixon, Andrea L.

2013-01-01

Women's spirituality has unique characteristics that are often ignored within the spirituality literature. The authors review the literature on women's spirituality to reveal the major themes women have identified as relevant to their spiritual journeys across the life span. Implications for counseling and ideas for practice are included after…

Spatial Abilities across the Adult Life Span

ERIC Educational Resources Information Center

Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana

2014-01-01

The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showed…

Sensorimotor Synchronization across the Life Span

ERIC Educational Resources Information Center

Drewing, Knut; Aschersleben, Gisa; Li, Shu-Chen

2006-01-01

The present study investigates the contribution of general processing resources as well as other more specific factors to the life-span development of sensorimotor synchronization and its component processes. Within a synchronization tapping paradigm, a group of 286 participants, 6 to 88 years of age, were asked to synchronize finger taps with…

Sex-Role Inconstancy, Biology, and Successful Aging: A Dialectical Model

ERIC Educational Resources Information Center

Sinnott, Jan Dynda

1977-01-01

This paper examines sex-role inconstancy from a life-span point of view. New environmental realities and an increasing life-span may make traditional sex roles less functional in old age. Evidence is presented for more successful aging in persons manifesting convergent sex-role behavior. (Author)

Redesign of a Life Span Development Course Using Fink's Taxonomy

ERIC Educational Resources Information Center

Fallahi, Carolyn R.

2008-01-01

This study compared a traditional lecture-based life span development course to the same course redesigned using Fink's (2003) taxonomy of significant learning. The goals, activities, and feedback within the course corresponded to Fink's 6 taxa (knowledge, application, integration, human dimension, caring, learning how to learn). Undergraduates in…

Neuromodulation of Behavioral and Cognitive Development across the Life Span

ERIC Educational Resources Information Center

Li, Shu-Chen

2012-01-01

Among other mechanisms, behavioral and cognitive development entail, on the one hand, contextual scaffolding and, on the other hand, neuromodulation of adaptive neurocognitive representations across the life span. Key brain networks underlying cognition, emotion, and motivation are innervated by major transmitter systems (e.g., the catecholamines…

Vitamins and aging: pathways to NAD+ synthesis.

PubMed

Denu, John M

2007-05-04

Recent genetic evidence reveals additional salvage pathways for NAD(+) synthesis. In this issue, Belenky et al. (2007) report that nicotinamide riboside, a new NAD(+) precursor, regulates Sir2 deacetylase activity and life span in yeast. The ability of nicotinamide riboside to enhance life span does not depend on calorie restriction.

Lactobacillus salivarius strain FDB89 induced longevity in Caenorhabditis elegans by dietary restriction.

PubMed

Zhao, Yang; Zhao, Liang; Zheng, Xiaonan; Fu, Tianjiao; Guo, Huiyuan; Ren, Fazheng

2013-04-01

In this study, we utilized the nematode Caenorhabditis elegans to assess potential life-expanding effect of Lactobacillus salivarius strain FDB89 (FDB89) isolated from feces of centenarians in Bama County (Guangxi, China). This study showed that feeding FDB89 extended the mean life span in C. elegans by up to 11.9% compared to that of control nematodes. The reduced reproductive capacities, pharyngeal pumping rate, growth, and increased superoxide dismutase (SOD) activity and XTT reduction capacity were also observed in FDB89 feeding worms. To probe the anti-aging mechanism further, we incorporated a food gradient feeding assay and assayed the life span of eat-2 mutant. The results demonstrated that the maximal life span of C. elegans fed on FDB89 was achieved at the concentration of 1.0 mg bacterial cells/plate, which was 10-fold greater than that of C. elegans fed on E. coli OP50 (0.1 mg bacterial cells/plate). However, feeding FDB89 could not further extend the life span of eat-2 mutant. These results indicated that FDB89 modulated the longevity of C. elegans in a dietary restriction-dependent manner and expanded the understanding of anti-aging effect of probiotics.

ProteomeVis: a web app for exploration of protein properties from structure to sequence evolution across organisms' proteomes.

PubMed

Razban, Rostam M; Gilson, Amy I; Durfee, Niamh; Strobelt, Hendrik; Dinkla, Kasper; Choi, Jeong-Mo; Pfister, Hanspeter; Shakhnovich, Eugene I

2018-05-08

Protein evolution spans time scales and its effects span the length of an organism. A web app named ProteomeVis is developed to provide a comprehensive view of protein evolution in the S. cerevisiae and E. coli proteomes. ProteomeVis interactively creates protein chain graphs, where edges between nodes represent structure and sequence similarities within user-defined ranges, to study the long time scale effects of protein structure evolution. The short time scale effects of protein sequence evolution are studied by sequence evolutionary rate (ER) correlation analyses with protein properties that span from the molecular to the organismal level. We demonstrate the utility and versatility of ProteomeVis by investigating the distribution of edges per node in organismal protein chain universe graphs (oPCUGs) and putative ER determinants. S. cerevisiae and E. coli oPCUGs are scale-free with scaling constants of 1.79 and 1.56, respectively. Both scaling constants can be explained by a previously reported theoretical model describing protein structure evolution (Dokholyan et al., 2002). Protein abundance most strongly correlates with ER among properties in ProteomeVis, with Spearman correlations of -0.49 (p-value<10-10) and -0.46 (p-value<10-10) for S. cerevisiae and E. coli, respectively. This result is consistent with previous reports that found protein expression to be the most important ER determinant (Zhang and Yang, 2015). ProteomeVis is freely accessible at http://proteomevis.chem.harvard.edu. Supplementary data are available at Bioinformatics. shakhnovich@chemistry.harvard.edu.

Friendship in childhood and adulthood: lessons across the life span.

PubMed

Sherman, A M; de Vries, B; Lansford, J E

2000-01-01

Friendship occupies an important place in the growing body of literature in child development and gerontological research. As such, it may be useful for researchers from both fields to consider what can be learned from work carried out in each tradition. Therefore, we present a selected review of topics in friendship research across the life span. Through discussion of the value of friendship, the development of friendship, challenges to friendship, the gendered nature of friendship, and the connection between friends and family, points of commonality and contrast are identified. We conclude by presenting possible avenues for future investigation for researchers interested in friendship at any point in the life span.

Weight concern across the life-span: relationship to self-esteem and feminist identity.

PubMed

Tiggemann, M; Stevens, C

1999-07-01

The aim of this study was to investigate the correlates of weight concern across the life-span. Questionnaires assessing weight concern, self-esteem, and feminist attitudes were completed in their homes by 180 women aged between 18 and 60 years. It was found that there was a negative relationship between weight concern and self-esteem for 30 to 49-year-old women, but not for younger or older women. A similar pattern held for feminist attitudes. Among 30 to 49-year-old women, a strong feminist orientation related to a lesser concern with weight. It was concluded that the meaning and experience of body weight and size change across the life-span.

Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

PubMed

Karayannis, Miltiades I; Efstathiou, Constantinos E

2012-12-15

In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life. Copyright © 2012 Elsevier B.V. All rights reserved.

Age Stereotypes and Self-Views Revisited: Patterns of Internalization and Projection Processes Across the Life Span.

PubMed

Kornadt, Anna E; Voss, Peggy; Rothermund, Klaus

2017-07-01

We investigated processes of age stereotype internalization into the self and projection of self-views onto age stereotypes from a life-span perspective, taking age-related differences in the relevance of life domains into account. Age stereotypes and self-views in eight life domains were assessed in a sample of N = 593 persons aged 30-80 years (T1) at two time points that were separated by a 4-year time interval. We estimated cross-lagged projection and internalization effects in multigroup structural equation models. Internalization and projection effects were contingent on age group and life domain: Internalization effects were strongest in the young and middle-aged groups and emerged in the domains family, personality, work, and leisure. Projection effects in different domains were most pronounced for older participants. Our findings suggest that the internalization of age stereotypes is triggered by domain-specific expectations of impending age-related changes and transitions during certain phases of the life span. Projection processes, however, seem to occur in response to changes that have already been experienced by the individual. Our study demonstrates the dynamic interrelation of age stereotypes and self-views across the life course and highlights the importance of a differentiated, life-span perspective for the understanding of these mechanisms. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Attachment and the Processing of Social Information across the Life Span: Theory and Evidence

ERIC Educational Resources Information Center

Dykas, Matthew J.; Cassidy, Jude

2011-01-01

Researchers have used J. Bowlby's (1969/1982, 1973, 1980, 1988) attachment theory frequently as a basis for examining whether experiences in close personal relationships relate to the processing of social information across childhood, adolescence, and adulthood. We present an integrative life-span-encompassing theoretical model to explain the…

Effects of a Short Strategy Training on Metacognitive Monitoring across the Life-Span

ERIC Educational Resources Information Center

von der Linden, Nicole; Löffler, Elisabeth; Schneider, Wolfgang

2015-01-01

The present study was conducted to explore the potential positive influence of a short strategy training on metacognitive monitoring competencies covering a life-span approach. Participants of four age groups (3rd-grade children, adolescents, younger and older adults) concluded a paired-associate learning task. Additionally, they gave delayed…

Psychopathology in Williams Syndrome: The Effect of Individual Differences across the Life Span

ERIC Educational Resources Information Center

Dodd, Helen F.; Porter, Melanie A.

2009-01-01

This research aimed to comprehensively explore psychopathology in Williams syndrome (WS) across the life span and evaluate the relationship between psychopathology and age category (child or adult), gender, and cognitive ability. The parents of 50 participants with WS, ages 6-50 years, were interviewed using the Schedule for Affective Disorders…

Influence of Domain Knowledge on Monitoring Performance across the Life Span

ERIC Educational Resources Information Center

Löffler, Elisabeth; von der Linden, Nicole; Schneider, Wolfgang

2016-01-01

Two studies were conducted to investigate effects of domain knowledge on metacognitive monitoring across the life span in materials of different complexity. Participants from 4 age groups (3rd-grade children, adolescents, younger and older adults) were compared using an expert-novice paradigm. In Study 1, soccer experts' and novices'…

Reading through the Life Span: Individual Differences in Psycholinguistic Effects

ERIC Educational Resources Information Center

Davies, Rob A. I.; Arnell, Ruth; Birchenough, Julia M. H.; Grimmond, Debbie; Houlson, Sam

2017-01-01

The effects of psycholinguistic variables are critical to the evaluation of theories about the cognitive reading system. However, reading research has tended to focus on the impact of key variables on average performance. We report the first investigation examining variation in psycholinguistic effects across the life span, from childhood into old…

Getting Together: Social Contact Frequency across the Life Span

ERIC Educational Resources Information Center

Sander, Julia; Schupp, Jürgen; Richter, David

2017-01-01

Frequent social interactions are strongly linked to positive affect, longevity, and good health. Although there has been extensive research on changes in the size of social networks over time, little attention has been given to the development of contact frequency across the life span. In this cohort-sequential longitudinal study, we examined…

Thermoregulatory, Cardiovascular, and Metabolic Responses to Mild Caloric Restriction in the Brown Norway Rat

EPA Science Inventory

Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known on the regulation of CR-induced h...

Assistive Device Use in Visually Impaired Older Adults: Role of Control Beliefs

ERIC Educational Resources Information Center

Becker, Stefanie; Wahl, Hans-Werner; Schilling, Oliver; Burmedi, David

2005-01-01

Purpose: We investigate whether psychological control, conceptually framed within the life-span theory of control by Heckhausen and Schulz, drives assistive device use in visually impaired elders. In particular, we expect the two primary control modes differentiated in the life-span theory of control (i.e., selective primary and compensatory…

Body Image across the Life Span in Adult Women: The Role of Self-Objectification.

ERIC Educational Resources Information Center

Tiggemann, Marika; Lynch, Jessica E.

2001-01-01

Investigated body image across life span in cross-section of women ages 20-84 years. Found that although body dissatisfaction remained stable, self-objectification, habitual body monitoring, appearance anxiety, and disordered eating all significantly decreased with age. Self- objectification mediated the relationship between age and disordered…

Dopa decarboxylase (Ddc) affects variation in Drosophila longevity.

PubMed

De Luca, Maria; Roshina, Nataliya V; Geiger-Thornsberry, Gretchen L; Lyman, Richard F; Pasyukova, Elena G; Mackay, Trudy F C

2003-08-01

Mutational analyses in model organisms have shown that genes affecting metabolism and stress resistance regulate life span, but the genes responsible for variation in longevity in natural populations are largely unidentified. Previously, we mapped quantitative trait loci (QTLs) affecting variation in longevity between two Drosophila melanogaster strains. Here, we show that the longevity QTL in the 36E;38B cytogenetic interval on chromosome 2 contains multiple closely linked QTLs, including the Dopa decarboxylase (Ddc) locus. Complementation tests to mutations show that Ddc is a positional candidate gene for life span in these strains. Linkage disequilibrium (LD) mapping in a sample of 173 alleles from a single population shows that three common molecular polymorphisms in Ddc account for 15.5% of the genetic contribution to variance in life span from chromosome 2. The polymorphisms are in strong LD, and the effects of the haplotypes on longevity suggest that the polymorphisms are maintained by balancing selection. DDC catalyzes the final step in the synthesis of the neurotransmitters, dopamine and serotonin. Thus, these data implicate variation in the synthesis of bioamines as a factor contributing to natural variation in individual life span.

The development of memory efficiency and value-directed remembering across the life span: a cross-sectional study of memory and selectivity.

PubMed

Castel, Alan D; Humphreys, Kathryn L; Lee, Steve S; Galván, Adriana; Balota, David A; McCabe, David P

2011-11-01

Although attentional control and memory change considerably across the life span, no research has examined how the ability to strategically remember important information (i.e., value-directed remembering) changes from childhood to old age. The present study examined this in different age groups across the life span (N = 320, 5-96 years old). A selectivity task was used in which participants were asked to study and recall items worth different point values in order to maximize their point score. This procedure allowed for measures of memory quantity/capacity (number of words recalled) and memory efficiency/selectivity (the recall of high-value items relative to low-value items). Age-related differences were found for memory capacity, as young adults recalled more words than the other groups. However, in terms of selectivity, younger and older adults were more selective than adolescents and children. The dissociation between these measures across the life span illustrates important age-related differences in terms of memory capacity and the ability to selectively remember high-value information.

Evidence for a relationship between longevity of mammalian species and life spans of normal fibroblasts in vitro and erythrocytes in vivo

PubMed Central

Röhme, Dan

1981-01-01

The replicative life spans of mammalian fibroblasts in vitro were studied in a number of cell cultures representing eight species. Emphasis was placed on determining the population doubling level at which phase III (a period of decrease in the rate of proliferation) and chromosomal alterations occur. All the cell cultures studied went through a growth crisis, a period of apparent growth cessation lasting for at least 2 weeks. In most cultures, the crisis represented the end of their replicative capacities, but in some cultures cell proliferation was resumed after the crisis. A predominantly diploid chromosome constitution (more than 75%) was demonstrated prior to the growth crisis. In cultures in which cell proliferation was resumed after the crisis, a nondiploid constitution prevailed in all cases except the rat (with 90% or more diploid cells all the time). The growth crisis occurred at population doubling levels that were characteristic for the species and was shown to be related to the species' maximal life span by a strict power law, being proportional to the square root of the maximal life span. Based on data in the literature, the same relationship was also valid for the lifespans of circulating mammalian erythrocytes in vivo. These results may indicate the prevalence of a common functional basis regulating the life span of fibroblasts and erythrocytes and thus operating in replicative as well as postmitotic cells in vitro and in vivo. PMID:6946449

Dietary Interventions to Extend Life Span and Health Span Based on Calorie Restriction

PubMed Central

Minor, Robin K.; Allard, Joanne S.; Younts, Caitlin M.; Ward, Theresa M.

2010-01-01

The societal impact of obesity, diabetes, and other metabolic disorders continues to rise despite increasing evidence of their negative long-term consequences on health span, longevity, and aging. Unfortunately, dietary management and exercise frequently fail as remedies, underscoring the need for the development of alternative interventions to successfully treat metabolic disorders and enhance life span and health span. Using calorie restriction (CR)—which is well known to improve both health and longevity in controlled studies—as their benchmark, gerontologists are coming closer to identifying dietary and pharmacological therapies that may be applicable to aging humans. This review covers some of the more promising interventions targeted to affect pathways implicated in the aging process as well as variations on classical CR that may be better suited to human adaptation. PMID:20371545

The Evolution Of Telework In The Federal Government

DOT National Transportation Integrated Search

2000-02-01

This paper documents the evolution of the Telework movement in the Federal government. This movement, which has spanned the last quarter century, is still unfolding and has yet to reach its zenith. The history of Federal telework reflects the evoluti...

Conceptualizing the origin of life in terms of evolution

NASA Astrophysics Data System (ADS)

Takeuchi, N.; Hogeweg, P.; Kaneko, K.

2017-11-01

In this opinion piece, we discuss how to place evolution in the context of origin-of-life research. Our discussion starts with a popular definition: `life is a self-sustained chemical system capable of undergoing Darwinian evolution'. According to this definition, the origin of life is the same as the origin of evolution: evolution is the `end' of the origin of life. This perspective, however, has a limitation, in that the ability of evolution in and of itself is insufficient to explain the origin of life as we know it, as indicated by Spiegelman's and Lincoln and Joyce's experiments. This limitation provokes a crucial question: What conditions are required for replicating systems to evolve into life? From this perspective, the origin of life includes the emergence of life through evolution: evolution is a `means' of the origin of life. After reviewing Eigen's pioneering work on this question, we mention our ongoing work suggesting that a key condition might be conflicting multi-level evolution. Taken together, there are thus two questions regarding the origin of life: how evolution gets started, and how evolution produces life. Evolution is, therefore, at the centre of the origin of life, where the two lines of enquiry must meet. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Cutaneous infectious diseases: Kids are not just little people.

PubMed

Admani, Shehla; Jinna, Sphoorthi; Friedlander, Sheila Fallon; Sloan, Brett

2015-01-01

The changes in immune response that occur with age play a significant role in disease presentation and patient management. Evolution of the innate and adaptive immune systems throughout life, influenced partly by hormonal changes associated with puberty, plays a role in the differences between pediatric and adult response to disease. We review a series of manifestations of dermatologic infectious diseases spanning bacterial, viral, and fungal origins that can be seen in both pediatric and adult age groups and highlight similarities and differences in presentation and disease course. Therapeutic options are also discussed for these infectious diseases, with particular attention to variations in management between these population subgroups, given differences in pharmacokinetics and side effect profiles. Published by Elsevier Inc.

Age Differences and Educational Attainment across the Life Span on Three Generations of Wechsler Adult Scales

ERIC Educational Resources Information Center

Kaufman, A. S.; Salthouse, T. A.; Scheiber, C.; Chen, H.

2016-01-01

Patterns of maintenance of ability across the life span have been documented on tests of knowledge ("Gc"), as have patterns of steady decline on measures of reasoning ("Gf/Gv"), working memory ("Gsm"), and speed ("Gs"). Whether these patterns occur at the same rate for adults from different educational…

Age Differences in Five Personality Domains across the Life Span

ERIC Educational Resources Information Center

Allemand, Mathias; Zimprich, Daniel; Hendriks, A. A. Jolijn

2008-01-01

The present study addresses the issue of age differences in 5 personality domains across the life span in a cross-sectional study. In contrast to most previous studies, the present study follows a methodologically more rigorous approach to warrant that age-related differences in personality structure and mean level can be meaningfully compared. It…

Developmental Change in Proactive Interference across the Life Span: Evidence from Two Working Memory Tasks

ERIC Educational Resources Information Center

Loosli, Sandra V.; Rahm, Benjamin; Unterrainer, Josef M.; Weiller, Cornelius; Kaller, Christoph P.

2014-01-01

Working memory (WM) as the ability to temporarily maintain and manipulate various kinds of information is known to be affected by proactive interference (PI) from previously relevant contents, but studies on developmental changes in the susceptibility to PI are scarce. In the present study, we investigated life span development of item-specific…

Life-Span Issues in the Fair and Non-Discriminatory Evaluation of Workers.

ERIC Educational Resources Information Center

Alexander, Ralph A.; Barrett, Gerald V.

Until recently, older workers have not been recognized as a group requiring special attention in the area of fair employment practices. Thus, progress has been slow towards the development of valid and reliable indices of performance which are applicable across the life span. Research shows that many measures of employee evaluation provide no…

Essentialist Reasoning and Knowledge Effects on Biological Reasoning in Young Children

ERIC Educational Resources Information Center

Herrmann, Patricia A.; French, Jason A.; DeHart, Ganie B.; Rosengren, Karl S.

2013-01-01

Biological kinds undergo a variety of changes during their life span, and these changes vary in degree by organism. Understanding that an organism, such as a caterpillar, maintains category identity over its life span despite dramatic changes is a key concept in biological reasoning. At present, we know little about the developmental trajectory of…

Cell longevity and sustained primary growth in palm stems.

PubMed

Tomlinson, P Barry; Huggett, Brett A

2012-12-01

Longevity, or organismal life span, is determined largely by the period over which constituent cells can function metabolically. Plants, with modular organization (the ability continually to develop new organs and tissues) differ from animals, with unitary organization (a fixed body plan), and this difference is reflected in their respective life spans, potentially much longer in plants than animals. We draw attention to the observation that palm trees, as a group of monocotyledons without secondary growth comparable to that of lignophytes (plants with secondary growth from a bifacial cambium), retain by means of sustained primary growth living cells in their trunks throughout their organismal life span. Does this make palms the longest-lived trees because they can grow as individuals for several centuries? No conventional lignophyte retains living metabolically active differentiated cell types in its trunk for this length of time, even though the tree as a whole can exist for millennia. Does this contrast also imply that the long-lived cells in a palm trunk have exceptional properties, which allows this seeming immortality? We document the long-life of many tall palm species and their inherent long-lived stem cell properties, comparing such plants to conventional trees. We provide a summary of aspects of cell age and life span in animals and plants. Cell replacement is a feature of animal function, whereas conventional trees rely on active growth centers (meristems) to sustain organismal development. However, the long persistence of living cells in palm trunks is seen not as evidence for unique metabolic processes that sustain longevity, but is a consequence of unique constructional features. This conclusion suggests that the life span of plant cells is not necessarily genetically determined.

From menarche to menopause: the fertile life span of celiac women.

PubMed

Santonicola, Antonella; Iovino, Paola; Cappello, Carmelina; Capone, Pietro; Andreozzi, Paolo; Ciacci, Carolina

2011-10-01

We evaluated menopause-associated disorders and fertile life span in women with celiac disease (CD) under untreated conditions and after long-term treatment with a gluten-free diet. The participants were 33 women with CD after menopause (untreated CD group), 25 celiac women consuming a gluten-free diet at least 10 years before menopause (treated CD group), and 45 healthy volunteers (control group). The Menopause Rating Scale questionnaire was used to gather information on menopause-associated disorders. The International Physical Activity Questionnaire was used to acquire information on physical activity. Untreated celiac women had a shorter duration of fertile life span than did the control women because of an older age of menarche and a younger age of menopause (P < 0.01). The scores for hot flushes, muscle/joint problems, and irritability were higher in untreated celiac women than in the control women (higher by 49.4%, 121.4%, and 58.6%, respectively; P < 0.05). In comparison with untreated CD, long-lasting treatment of CD was not associated with a significant difference in the duration of fertile life span, but was only associated with a significant reduction in muscle/joint problems (a reduction of 47.1%; P < 0.05). Late menarche and early menopause causes a shorter fertile period in untreated celiac women compared with control women. A gluten-free diet that started at least 10 years before menopause prolongs the fertile life span of celiac women. The perception of intensity of hot flushes and irritability is more severe in untreated celiac women than in controls. Low physical exercise and/or poorer quality of life frequently reported by untreated celiac women might be the cause of reduced discomfort tolerance, thus increasing the subjective perception of menopausal symptoms.

Noise performance of microwave humidity sounders over their lifetime

NASA Astrophysics Data System (ADS)

Hans, Imke; Burgdorf, Martin; John, Viju O.; Mittaz, Jonathan; Buehler, Stefan A.

2017-12-01

The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2), Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) to date have been providing data records for 25 years. So far, the data records lack uncertainty information essential for constructing consistent long time data series. In this study, we assess the quality of the recorded data with respect to the uncertainty caused by noise. We calculate the noise on the raw calibration counts from the deep space views (DSVs) of the instrument and the noise equivalent differential temperature (NEΔT) as a measure for the radiometer sensitivity. For this purpose, we use the Allan deviation that is not biased from an underlying varying mean of the data and that has been suggested only recently for application in atmospheric remote sensing. Moreover, we use the bias function related to the Allan deviation to infer the underlying spectrum of the noise. As examples, we investigate the noise spectrum in flight for some instruments. For the assessment of the noise evolution in time, we provide a descriptive and graphical overview of the calculated NEΔT over the life span of each instrument and channel. This overview can serve as an easily accessible information for users interested in the noise performance of a specific instrument, channel and time. Within the time evolution of the noise, we identify periods of instrumental degradation, which manifest themselves in an increasing NEΔT, and periods of erratic behaviour, which show sudden increases of NEΔT interrupting the overall smooth evolution of the noise. From this assessment and subsequent exclusion of the aforementioned periods, we present a chart showing available data records with NEΔT < 1 K. Due to overlapping life spans of the instruments, these reduced data records still cover without gaps the time since 1994 and may therefore serve as a first step for constructing long time series. Our method for count noise estimation, that has been used in this study, will be used in the data processing to provide input values for the uncertainty propagation in the generation of a new set of Fundamental Climate Data Records (FCDRs) that are currently produced in the project Fidelity and Uncertainty in Climate data records from Earth Observation (FIDUCEO).

The Genome and Methylome of a Beetle with Complex Social Behavior, Nicrophorus vespilloides (Coleoptera: Silphidae).

PubMed

Cunningham, Christopher B; Ji, Lexiang; Wiberg, R Axel W; Shelton, Jennifer; McKinney, Elizabeth C; Parker, Darren J; Meagher, Richard B; Benowitz, Kyle M; Roy-Zokan, Eileen M; Ritchie, Michael G; Brown, Susan J; Schmitz, Robert J; Moore, Allen J

2015-10-09

Testing for conserved and novel mechanisms underlying phenotypic evolution requires a diversity of genomes available for comparison spanning multiple independent lineages. For example, complex social behavior in insects has been investigated primarily with eusocial lineages, nearly all of which are Hymenoptera. If conserved genomic influences on sociality do exist, we need data from a wider range of taxa that also vary in their levels of sociality. Here, we present the assembled and annotated genome of the subsocial beetle Nicrophorus vespilloides, a species long used to investigate evolutionary questions of complex social behavior. We used this genome to address two questions. First, do aspects of life history, such as using a carcass to breed, predict overlap in gene models more strongly than phylogeny? We found that the overlap in gene models was similar between N. vespilloides and all other insect groups regardless of life history. Second, like other insects with highly developed social behavior but unlike other beetles, does N. vespilloides have DNA methylation? We found strong evidence for an active DNA methylation system. The distribution of methylation was similar to other insects with exons having the most methylated CpGs. Methylation status appears highly conserved; 85% of the methylated genes in N. vespilloides are also methylated in the hymentopteran Nasonia vitripennis. The addition of this genome adds a coleopteran resource to answer questions about the evolution and mechanistic basis of sociality and to address questions about the potential role of methylation in social behavior. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Coping with cyclic oxygen availability: evolutionary aspects.

PubMed

Flück, Martin; Webster, Keith A; Graham, Jeffrey; Giomi, Folco; Gerlach, Frank; Schmitz, Anke

2007-10-01

Both the gradual rise in atmospheric oxygen over the Proterozoic Eon as well as episodic fluctuations in oxygen over several million-year time spans during the Phanerozoic Era, have arguably exerted strong selective forces on cellular and organismic respiratory specialization and evolution. The rise in atmospheric oxygen, some 2 billion years after the origin of life, dramatically altered cell biology and set the stage for the appearance of multicelluar life forms in the Vendian (Ediacaran) Period of the Neoproterozoic Era. Over much of the Paleozoic, the level of oxygen in the atmosphere was near the present atmospheric level (21%). In the Late Paleozoic, however, there were extended times during which the level of atmospheric oxygen was either markedly lower or markedly higher than 21%. That these Paleozoic shifts in atmospheric oxygen affected the biota is suggested by the correlations between: (1) Reduced oxygen and the occurrences of extinctions, a lowered biodiversity and shifts in phyletic succession, and (2) During hyperoxia, the corresponding occurrence of phenomena such as arthropod gigantism, the origin of insect flight, and the evolution of vertebrate terrestriality. Basic similarities in features of adaptation to hyopoxia, manifest in living organisms at levels ranging from genetic and cellular to physiological and behavioral, suggest the common and early origin of a suite of adaptive mechanisms responsive to fluctuations in ambient oxygen. Comparative integrative approaches addressing the molecular bases of phenotypic adjustments to cyclic oxygen fluctuation provide broad insight into the incremental steps leading to the early evolution of homeostatic respiratory mechanisms and to the specialization of organismic respiratory function.

Pomegranate Juice Enhances Healthy Lifespan in Drosophila melanogaster: An Exploratory Study

PubMed Central

Balasubramani, Subramani Paranthaman; Mohan, Jayaram; Chatterjee, Arunita; Patnaik, Esha; Kukkupuni, Subrahmanya Kumar; Nongthomba, Upendra; Venkatasubramanian, Padmavathy

2014-01-01

Exploring innovative ways to ensure healthy aging of populations is a pre-requisite to contain rising healthcare costs. Scientific research into the principles and practices of traditional medicines can provide new insights and simple solutions to lead a healthy life. Rasayana is a dedicated branch of Ayurveda (an Indian medicine) that deals with methods to increase vitality and delay aging through the use of diet, herbal supplements, and other lifestyle practices. The life-span and health-span enhancing actions of the fruits of pomegranate (Punica granatum L.), a well-known Rasayana, were tested on Drosophila melanogaster (fruitfly) model. Supplementation of standard corn meal with 10% (v/v) pomegranate juice (PJ) extended the life-span of male and female flies by 18 and 8%, respectively. When male and female flies were mixed and reared together, there was 19% increase in the longevity of PJ fed flies, as assessed by MSD, the median survival day (24.8). MSD for control and resveratrol (RV) groups was at 20.8 and 23.1 days, respectively. A two-fold enhancement in fecundity, improved resistance to oxidative stress (H2O2 and paraquat induced) and to Candida albicans infection were observed in PJ fed flies. Further, the flies in the PJ fed group were physically active over an extended period of time, as assessed by the climbing assay. PJ thus outperformed both control and RV groups in the life-span and health-span parameters tested. This study provides the scope to explore the potential of PJ as a nutraceutical to improve health span and lifespan in human beings. PMID:25566518

Mammalian genes induce partially reprogrammed pluripotent stem cells in non-mammalian vertebrate and invertebrate species

PubMed Central

Rosselló, Ricardo Antonio; Chen, Chun-Chun; Dai, Rui; Howard, Jason T; Hochgeschwender, Ute; Jarvis, Erich D

2013-01-01

Cells are fundamental units of life, but little is known about evolution of cell states. Induced pluripotent stem cells (iPSCs) are once differentiated cells that have been re-programmed to an embryonic stem cell-like state, providing a powerful platform for biology and medicine. However, they have been limited to a few mammalian species. Here we found that a set of four mammalian transcription factor genes used to generate iPSCs in mouse and humans can induce a partially reprogrammed pluripotent stem cell (PRPSCs) state in vertebrate and invertebrate model organisms, in mammals, birds, fish, and fly, which span 550 million years from a common ancestor. These findings are one of the first to show cross-lineage stem cell-like induction, and to generate pluripotent-like cells for several of these species with in vivo chimeras. We suggest that the stem-cell state may be highly conserved across a wide phylogenetic range. DOI: http://dx.doi.org/10.7554/eLife.00036.001 PMID:24015354

Precambrian Time - The Story of the Early Earth

USGS Publications Warehouse

Lindsey, D.A.

2007-01-01

The Precambrian is the least-understood part of Earth history, yet it is arguably the most important. Precambrian time spans almost nine-tenths of Earth history, from the formation of the Earth to the dawn of the Cambrian Period. It represents time so vast and long ago that it challenges all comprehension. The Precambrian is the time of big questions. How old is the Earth? How old are the oldest rocks and continents? What was the early Earth like? What was the early atmosphere like? When did life appear, and what did it look like? And, how do we know this? In recent years, remarkable progress has been made in understanding the early evolution of the Earth and life itself. Yet, the scientific story of the early Earth is still a work in progress, humankind's latest attempt to understand the planet. Like previous attempts, it too will change as we learn more about the Earth. Read on to discover what we know now, in the early 21st century.

Health span approximates life span among many supercentenarians: compression of morbidity at the approximate limit of life span.

PubMed

Andersen, Stacy L; Sebastiani, Paola; Dworkis, Daniel A; Feldman, Lori; Perls, Thomas T

2012-04-01

We analyze the relationship between age of survival, morbidity, and disability among centenarians (age 100-104 years), semisupercentenarians (age 105-109 years), and supercentenarians (age 110-119 years). One hundred and four supercentenarians, 430 semisupercentenarians, 884 centenarians, 343 nonagenarians, and 436 controls were prospectively followed for an average of 3 years (range 0-13 years). The older the age group, generally, the later the onset of diseases, such as cancer, cardiovascular disease, dementia, and stroke, as well as of cognitive and functional decline. The hazard ratios for these individual diseases became progressively less with older and older age, and the relative period of time spent with disease was lower with increasing age group. We observed a progressive delay in the age of onset of physical and cognitive function impairment, age-related diseases, and overall morbidity with increasing age. As the limit of human life span was effectively approached with supercentenarians, compression of morbidity was generally observed.

Health Span Approximates Life Span Among Many Supercentenarians: Compression of Morbidity at the Approximate Limit of Life Span

PubMed Central

Andersen, Stacy L.; Sebastiani, Paola; Dworkis, Daniel A.; Feldman, Lori

2012-01-01

We analyze the relationship between age of survival, morbidity, and disability among centenarians (age 100–104 years), semisupercentenarians (age 105–109 years), and supercentenarians (age 110–119 years). One hundred and four supercentenarians, 430 semisupercentenarians, 884 centenarians, 343 nonagenarians, and 436 controls were prospectively followed for an average of 3 years (range 0–13 years). The older the age group, generally, the later the onset of diseases, such as cancer, cardiovascular disease, dementia, and stroke, as well as of cognitive and functional decline. The hazard ratios for these individual diseases became progressively less with older and older age, and the relative period of time spent with disease was lower with increasing age group. We observed a progressive delay in the age of onset of physical and cognitive function impairment, age-related diseases, and overall morbidity with increasing age. As the limit of human life span was effectively approached with supercentenarians, compression of morbidity was generally observed. PMID:22219514

Psychosocial stressors and the short life spans of legendary jazz musicians.

PubMed

Patalano, F

2000-04-01

Mean age at death of 168 legendary jazz musicians and 100 renowned classical musicians were compared to examine whether psychosocial stressors such as severe substance abuse, haphazard working conditions, lack of acceptance of jazz as an art form in the United States, marital and family discord, and a vagabond life style may have contributed to shortened life spans for the jazz musicians. Analysis indicated that the jazz musicians died at an earlier age (57.2 yr.) than the classical musicians (73.3 yr.).

Changes in Acoustic Characteristics of the Voice across the Life Span: Measures from Individuals 4-93 Years of Age

ERIC Educational Resources Information Center

Stathopoulos, Elaine T.; Huber, Jessica E.; Sussman, Joan E.

2011-01-01

Purpose: The purpose of the present investigation was to examine acoustic voice changes across the life span. Previous voice production investigations used small numbers of participants, had limited age ranges, and produced contradictory results. Method: Voice recordings were made from 192 male and female participants 4-93 years of age. Acoustic…

Modeling Life-Span Growth Curves of Cognition Using Longitudinal Data with Multiple Samples and Changing Scales of Measurement

ERIC Educational Resources Information Center

McArdle, John J.; Grimm, Kevin J.; Hamagami, Fumiaki; Bowles, Ryan P.; Meredith, William

2009-01-01

The authors use multiple-sample longitudinal data from different test batteries to examine propositions about changes in constructs over the life span. The data come from 3 classic studies on intellectual abilities in which, in combination, 441 persons were repeatedly measured as many as 16 times over 70 years. They measured cognitive constructs…

The Use of Digital Technologies across the Adult Life Span in Distance Education

ERIC Educational Resources Information Center

Jelfs, Anne; Richardson, John T. E.

2013-01-01

In June 2010, a survey was carried out to explore access to digital technology, attitudes to digital technology and approaches to studying across the adult life span in students taking courses with the UK Open University. In total, 7000 people were surveyed, of whom more than 4000 responded. Nearly all these students had access to a computer and…

Auditory Environment across the Life Span of Cochlear Implant Users: Insights from Data Logging

ERIC Educational Resources Information Center

Busch, Tobias; Vanpoucke, Filiep; van Wieringen, Astrid

2017-01-01

Purpose: We describe the natural auditory environment of people with cochlear implants (CIs), how it changes across the life span, and how it varies between individuals. Method: We performed a retrospective cross-sectional analysis of Cochlear Nucleus 6 CI sound-processor data logs. The logs were obtained from 1,501 people with CIs (ages 0-96…

The Development of Attentional Networks: Cross-Sectional Findings from a Life Span Sample

ERIC Educational Resources Information Center

Waszak, Florian; Li, Shu-Chen; Hommel, Bernhard

2010-01-01

Using a population-based sample of 263 individuals ranging from 6 to 89 years of age, we investigated the gains and losses in the abilities to (a) use exogenous cues to shift attention covertly and (b) ignore conflicting information across the life span. The participants' ability to shift visual attention was tested by a typical Posner-type…

Life-Span Development of Visual Working Memory: When Is Feature Binding Difficult?

ERIC Educational Resources Information Center

Cowan, Nelson; Naveh-Benjamin, Moshe; Kilb, Angela; Saults, J. Scott

2006-01-01

We asked whether the ability to keep in working memory the binding between a visual object and its spatial location changes with development across the life span more than memory for item information. Paired arrays of colored squares were identical or differed in the color of one square, and in the latter case, the changed color was unique on…

Gains and Losses in Creative Personality as Perceived by Adults across the Life Span

ERIC Educational Resources Information Center

Hui, Anna N. N.; Yeung, Dannii Y.; Sue-Chan, Christina; Chan, Kara; Hui, Desmond C. K.; Cheng, Sheung-Tak

2014-01-01

In this study, we used a life span model to study the subjective perception of creative personality (CP) in emerging, young, middle-aged, and older Hong Kong Chinese adults. We also asked participants to estimate the approximate age by which people develop and lose CP across adulthood. We expected an interesting interplay between internalized age…

Extending the Human Life Span: An Exploratory Study of Pro- and Anti-Longevity Attitudes

ERIC Educational Resources Information Center

Kogan, Nathan; Tucker, Jennifer; Porter, Matthew

2011-01-01

Successful efforts by biologists to substantially increase the life span of non-human animals has raised the possibility of extrapolation to humans, which in turn has given rise to bioethical argumentation, pro and con. The present study converts these arguments into pro- and anti-longevity items on a questionnaire and examines the structure and…

Attitudes Toward Death Across the Life Span.

ERIC Educational Resources Information Center

Maiden, Robert; Walker, Gail

To understand the change and development of people's attitudes toward death over the life span, a 62-item attitude questionnaire on death and dying was administered to 90 adults. Participants included five females and five males in each of nine age categories: 18-20, 20-24, 25-29, 30-34, 35-39, 40-49, 50-59, 60-64, and 65 or older. Participants…

Life-Span Differences in the Uses and Gratifications of Tablets: Implications for Older Adults

PubMed Central

Magsamen-Conrad, Kate; Dowd, John; Abuljadail, Mohammad; Alsulaiman, Saud; Shareefi, Adnan

2015-01-01

This study extends Uses and Gratifications theory by examining the uses and gratifications of a new technological device, the tablet computer, and investigating the differential uses and gratifications of tablet computers across the life-span. First, we utilized a six-week tablet training intervention to adapt and extend existing measures to the tablet as a technological device. Next, we used paper-based and online surveys (N=847), we confirmed four main uses of tablets: 1) Information Seeking, 2) Relationship Maintenance, 3) Style, 4) Amusement and Killing time, and added one additional use category 5) Organization. We discovered differences among the five main uses of tablets across the life-span, with older adults using tablets the least overall. Builders, Boomers, GenX and GenY all reported the highest means for information seeking. Finally, we used a structural equation model to examine how uses and gratifications predicts hours of tablet use. The study provides limitations and suggestions for future research and marketers. In particular, this study offers insight to the relevancy of theory as it applies to particular information and communication technologies and consideration of how different periods in the life-span affect tablet motivations. PMID:26113769

Life-Span Differences in the Uses and Gratifications of Tablets: Implications for Older Adults.

PubMed

Magsamen-Conrad, Kate; Dowd, John; Abuljadail, Mohammad; Alsulaiman, Saud; Shareefi, Adnan

2015-11-01

This study extends Uses and Gratifications theory by examining the uses and gratifications of a new technological device, the tablet computer, and investigating the differential uses and gratifications of tablet computers across the life-span. First, we utilized a six-week tablet training intervention to adapt and extend existing measures to the tablet as a technological device. Next, we used paper-based and online surveys ( N =847), we confirmed four main uses of tablets: 1) Information Seeking, 2) Relationship Maintenance, 3) Style, 4) Amusement and Killing time, and added one additional use category 5) Organization. We discovered differences among the five main uses of tablets across the life-span, with older adults using tablets the least overall. Builders, Boomers, GenX and GenY all reported the highest means for information seeking. Finally, we used a structural equation model to examine how uses and gratifications predicts hours of tablet use. The study provides limitations and suggestions for future research and marketers. In particular, this study offers insight to the relevancy of theory as it applies to particular information and communication technologies and consideration of how different periods in the life-span affect tablet motivations.

Life-span perspective of personality in dementia.

PubMed

Kolanowski, A M; Whall, A L

1996-01-01

To propose an alternative view of personality change in dementia by presenting existing evidence for the continuity of personality. As the population continues to age, dementing illnesses will account for a greater proportion of morbidity and mortality; the care of these people will have a significant effect on the health care system. Life-span perspective of personality continuity. SCOPE METHOD: Review of current literature on personality in dementia using Medline, 1980-1994; CINAHL, 1990-1994; and Psych Lit., 1980-1994. Although there are systematic shifts in personality with dementia, individuals tend to maintain their unique pattern of premorbid personality traits. The personalities of dementia patients seem to reflect adaptive patterns that served them in the past. Use of a life-span perspective can enhance individualized care for demented patients and advance theory development.

Demography of Genotypes: Failure of the Limited Life-Span Paradigm in Drosophila melanogaster

NASA Astrophysics Data System (ADS)

Curtsinger, James W.; Fukui, Hidenori H.; Townsend, David R.; Vaupel, James W.

1992-10-01

Experimental systems that are amenable to genetic manipulation can be used to address fundamental questions about genetic and nongenetic determinants of longevity. Analysis of large cohorts of ten genotypes of Drosophila melanogaster raised under conditions that favored extended survival has revealed variation between genotypes in both the slope and location of age-specific mortality curves. More detailed examination of a single genotype showed that the mortality trajectory was best fit by a two-stage Gompertz model, with no age-specific increase in mortality rates beyond 30 days after emergence. These results are contrary to the limited life-span paradigm, which postulates well-defined, genotype-specific limits on life-span and brief periods of intense and rapidly accelerating mortality rates at the oldest ages.

Accelerated Evolution and Functional Divergence of the Dim Light Visual Pigment Accompanies Cichlid Colonization of Central America.

PubMed

Hauser, Frances E; Ilves, Katriina L; Schott, Ryan K; Castiglione, Gianni M; López-Fernández, Hernán; Chang, Belinda S W

2017-10-01

Cichlids encompass one of the most diverse groups of fishes in South and Central America, and show extensive variation in life history, morphology, and colouration. While studies of visual system evolution in cichlids have focussed largely on the African rift lake species flocks, Neotropical cichlids offer a unique opportunity to investigate visual system evolution at broader temporal and geographic scales. South American cichlid colonization of Central America has likely promoted accelerated rates of morphological evolution in Central American lineages as they encountered reduced competition, renewed ecological opportunity, and novel aquatic habitats. To investigate whether such transitions have influenced molecular evolution of vision in Central American cichlids, we sequenced the dim-light rhodopsin gene in 101 Neotropical cichlid species, spanning the diversity of the clade. We find strong evidence for increased rates of evolution in Central American cichlid rhodopsin relative to South American lineages, and identify several sites under positive selection in rhodopsin that likely contribute to adaptation to different photic environments. We expressed a Neotropical cichlid rhodopsin protein invitro for the first time, and found that while its spectral tuning properties were characteristic of typical vertebrate rhodopsin pigments, the rate of decay of its active signalling form was much slower, consistent with dim light adaptation in other vertebrate rhodopsins. Using site-directed mutagenesis combined with spectroscopic assays, we found that a key amino acid substitution present in some Central American cichlids accelerates the rate of decay of active rhodopsin, which may mediate adaptation to clear water habitats. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Drosophila melanogaster as a model system of aluminum toxicity and aging.

PubMed

Kijak, Ewelina; Rosato, Ezio; Knapczyk, Katarzyna; Pyza, Elżbieta

2014-04-01

The aim of this study was to investigate the toxic effects of aluminum (Al) on the model organism-Drosophila melanogaster. The study is especially concerned with the effects of aluminum on the fruit fly's development, life span, and circadian rhythm in rest and activity. Flies were exposed to aluminum in concentrations from 40 to 280 mg/kg in rearing media or the flies were raised on control medium. Moreover, the life span of insects exposed to aluminum containing 40, 120, or 240 mg/kg of Al in the medium, only during their larval development, during the whole life cycle and only in their adult life was tested. To check if aluminum and aging cause changes in D. melanogaster behavior, the locomotor activity of flies at different ages was recorded. Results showed that aluminum is toxic in concentrations above 160 mg/kg in the rearing medium. Depending on Al concentration and time of exposure, the life span of the flies was shortened. At intermediate concentrations (120 mg/kg), however, Al had a stimulating effect on males increasing their life span and level of locomotor activity. At higher concentration the aluminum exposure increased or decreased the level of locomotor activity of D. melanogaster depending on age of flies. In addition, in the oldest insects reared on aluminum supplemented media and in mid-aged flies reared on the highest concentration of Al the daily rhythm of activity was disrupted. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Genomic Changes Associated with Reproductive and Migratory Ecotypes in Sockeye Salmon (Oncorhynchus nerka).

PubMed

Veale, Andrew J; Russello, Michael A

2017-10-01

Mechanisms underlying adaptive evolution can best be explored using paired populations displaying similar phenotypic divergence, illuminating the genomic changes associated with specific life history traits. Here, we used paired migratory [anadromous vs. resident (kokanee)] and reproductive [shore- vs. stream-spawning] ecotypes of sockeye salmon (Oncorhynchus nerka) sampled from seven lakes and two rivers spanning three catchments (Columbia, Fraser, and Skeena) in British Columbia, Canada to investigate the patterns and processes underlying their divergence. Restriction-site associated DNA sequencing was used to genotype this sampling at 7,347 single nucleotide polymorphisms, 334 of which were identified as outlier loci and candidates for divergent selection within at least one ecotype comparison. Sixty-eight of these outliers were present in two or more comparisons, with 33 detected across multiple catchments. Of particular note, one locus was detected as the most significant outlier between shore and stream-spawning ecotypes in multiple comparisons and across catchments (Columbia, Fraser, and Snake). We also detected several genomic islands of divergence, some shared among comparisons, potentially showing linked signals of differential selection. The single nucleotide polymorphisms and genomic regions identified in our study offer a range of mechanistic hypotheses associated with the genetic basis of O. nerka life history variation and provide novel tools for informing fisheries management. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Quantifying the Structure of Free Association Networks across the Life Span

ERIC Educational Resources Information Center

Dubossarsky, Haim; De Deyne, Simon; Hills, Thomas T.

2017-01-01

We investigate how the mental lexicon changes over the life span using free association data from over 8,000 individuals, ranging from 10 to 84 years of age, with more than 400 cue words per age group. Using network analysis, with words as nodes and edges defined by the strength of shared associations, we find that associative networks evolve in a…

Self-Esteem Development across the Life Span: A Longitudinal Study with a Large Sample from Germany

ERIC Educational Resources Information Center

Orth, Ulrich; Maes, Jürgen; Schmitt, Manfred

2015-01-01

The authors examined the development of self-esteem across the life span. Data came from a German longitudinal study with 3 assessments across 4 years of a sample of 2,509 individuals ages 14 to 89 years. The self-esteem measure used showed strong measurement invariance across assessments and birth cohorts. Latent growth curve analyses indicated…

Delayed accumulation of intestinal coliform bacteria enhances life span and stress resistance in Caenorhabditis elegans fed respiratory deficient E. coli.

PubMed

Gomez, Fernando; Monsalve, Gabriela C; Tse, Vincent; Saiki, Ryoichi; Weng, Emily; Lee, Laura; Srinivasan, Chandra; Frand, Alison R; Clarke, Catherine F

2012-12-20

Studies with the nematode model Caenorhabditis elegans have identified conserved biochemical pathways that act to modulate life span. Life span can also be influenced by the composition of the intestinal microbiome, and C. elegans life span can be dramatically influenced by its diet of Escherichia coli. Although C. elegans is typically fed the standard OP50 strain of E. coli, nematodes fed E. coli strains rendered respiratory deficient, either due to a lack coenzyme Q or the absence of ATP synthase, show significant life span extension. Here we explore the mechanisms accounting for the enhanced nematode life span in response to these diets. The intestinal load of E. coli was monitored by determination of worm-associated colony forming units (cfu/worm or coliform counts) as a function of age. The presence of GFP-expressing E. coli in the worm intestine was also monitored by fluorescence microscopy. Worms fed the standard OP50 E. coli strain have high cfu and GFP-labeled bacteria in their guts at the L4 larval stage, and show saturated coliform counts by day five of adulthood. In contrast, nematodes fed diets of respiratory deficient E. coli lacking coenzyme Q lived significantly longer and failed to accumulate bacteria within the lumen at early ages. Animals fed bacteria deficient in complex V showed intermediate coliform numbers and were not quite as long-lived. The results indicate that respiratory deficient Q-less E. coli are effectively degraded in the early adult worm, either at the pharynx or within the intestine, and do not accumulate in the intestinal tract until day ten of adulthood. The findings of this study suggest that the nematodes fed the respiratory deficient E. coli diet live longer because the delay in bacterial colonization of the gut subjects the worms to less stress compared to worms fed the OP50 E. coli diet. This work suggests that bacterial respiration can act as a virulence factor, influencing the ability of bacteria to colonize and subsequently harm the animal host. Respiratory deficient bacteria may pose a useful model for probing probiotic relationships within the gut microbiome in higher organisms.

Causes and consequences of variation in conifer leaf life-span

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich, P.B.; Koike, T.; Gower, S.T.

1995-07-01

Species with mutually supporting traits, such as high N{sub mass}, SLA, and A{sub mass}, and short leaf life-span, tend to inhabit either generally resource-rich environments or spatial and/or temporal microhabitats that are resource-rich in otherwise more limited habitats (e.g., {open_quotes}precipitation{close_quotes} ephemerals in warm deserts or spring ephemerals in the understory of temperate deciduous forests). In contrast, species with long leaf life-span often support foliage with low SLA, N{sub mass}, and A{sub mass}, and often grow in low-temperature limited, dry, and/or nutrient-poor environments. The contrast between evergreen and deciduous species, and the implications that emerge from such comparisons, can be consideredmore » a paradigm of modern ecological theory. However, based on the results of Reich et al. (1992) and Gower et al. (1993), coniferous species with foliage that persists for 9-10 years are likely to assimilate and allocate carbon and nutrients differently than other evergreen conifers that retain foliage for 2-3 years. Thus, attempts to contrast ecophysiological or ecosystem characteristics of evergreen versus deciduous life forms may be misleading, and pronounced differences among evergreen conifers may be ignored. Clearly, the deciduous-evergreen contrast, although useful in several ways, should be viewed from the broader perspective of a gradient in leaf life-span.« less

Evolution and Persistence of 5-um Hot Spots at the Galileo Probe entry Latitude

NASA Technical Reports Server (NTRS)

Fisher, B. M.

1997-01-01

We present a study on the longtudinal locations, morphology and evolution of the 5-um hot spots at 6.5 deg. N latitude (planetocentric), from an extensive IRTF-NSFCAM data set spanning more that 3 years, which includes the date of the Galileo Probe entry.

Extreme environments select for reproductive assurance: evidence from evening primroses (Oenothera).

PubMed

Evans, Margaret E K; Hearn, David J; Theiss, Kathryn E; Cranston, Karen; Holsinger, Kent E; Donoghue, Michael J

2011-07-01

Competing evolutionary forces shape plant breeding systems (e.g. inbreeding depression, reproductive assurance). Which of these forces prevails in a given population or species is predicted to depend upon such factors as life history, ecological conditions, and geographical context. Here, we examined two such predictions: that self-compatibility should be associated with the annual life history or extreme climatic conditions. We analyzed data from a clade of plants remarkable for variation in breeding system, life history and climatic conditions (Oenothera, sections Anogra and Kleinia, Onagraceae). We used a phylogenetic comparative approach and Bayesian or hybrid Bayesian tests to account for phylogenetic uncertainty. Geographic information system (GIS)-based climate data and ecological niche modeling allowed us to quantify climatic conditions. Breeding system and reproductive life span are not correlated in Anogra and Kleinia. Instead, self-compatibility is associated with the extremes of temperature in the coldest part of the year and precipitation in the driest part of the year. In the 60 yr since this pattern was anticipated, this is the first demonstration of a relationship between the evolution of self-compatibility and climatic extremes. We discuss possible explanations for this pattern and possible implications with respect to anthropogenic climate change. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ames, B.N.; Cathcart, R.; Schwiers, E.

During primate evolution, a major factor in lengthening life-span and decreasing age-specific cancer rates may have been improved protective mechanisms against oxygen radicals. We propose that one of these protective systems is plasma uric acid, the level of which increased markedly during primate evolution as a consequence of a series of mutations. Uric acid is a powerful antioxidant and is a scavenger of singlet oxygen and radicals. We show that, at physiological concentrations, urate reduces the oxo-heme oxidant formed by peroxide reaction with hemoglobin, protects erythrocyte ghosts against lipid peroxidation, and protects erythrocytes from peroxidative damage leading to lysis. Uratemore » is about as effective an antioxidant as ascorbate in these experiments. Urate is much more easily oxidized than deoxynucleosides by singlet oxygen and is destroyed by hydroxyl radicals at a comparable rate. The plasma urate level in humans (about 300 ..mu..M) is considerably higher than the ascorbate level, making it one of the major antioxidants in humans. Previous work on urate reported in the literature supports our experiments and interpretations, although the findings were not discussed in a physiological context.« less

Higher predation risk for insect prey at low latitudes and elevations.

PubMed

Roslin, Tomas; Hardwick, Bess; Novotny, Vojtech; Petry, William K; Andrew, Nigel R; Asmus, Ashley; Barrio, Isabel C; Basset, Yves; Boesing, Andrea Larissa; Bonebrake, Timothy C; Cameron, Erin K; Dáttilo, Wesley; Donoso, David A; Drozd, Pavel; Gray, Claudia L; Hik, David S; Hill, Sarah J; Hopkins, Tapani; Huang, Shuyin; Koane, Bonny; Laird-Hopkins, Benita; Laukkanen, Liisa; Lewis, Owen T; Milne, Sol; Mwesige, Isaiah; Nakamura, Akihiro; Nell, Colleen S; Nichols, Elizabeth; Prokurat, Alena; Sam, Katerina; Schmidt, Niels M; Slade, Alison; Slade, Victor; Suchanková, Alžběta; Teder, Tiit; van Nouhuys, Saskya; Vandvik, Vigdis; Weissflog, Anita; Zhukovich, Vital; Slade, Eleanor M

2017-05-19

Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution. Copyright © 2017, American Association for the Advancement of Science.

“Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes”

PubMed Central

Neafsey, Daniel E.; Waterhouse, Robert M.; Abai, Mohammad R.; Aganezov, Sergey S.; Alekseyev, Max A.; Allen, James E.; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A.; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W.; Blandin, Stephanie A.; Brockman, Andrew I.; Burkot, Thomas R.; Burt, Austin; Chan, Clara S.; Chauve, Cedric; Chiu, Joanna C.; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L.M.; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B.; Guelbeogo, Wamdaogo M.; Hall, Andrew B.; Han, Mira V.; Hlaing, Thaung; Hughes, Daniel S.T.; Jenkins, Adam M.; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G.; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C.; Kirmitzoglou, Ioannis K.; Koekemoer, Lizette L.; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K.N.; Lirakis, Manolis; Lobo, Neil F.; Lowy, Ernesto; MacCallum, Robert M.; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N.; Moore, Wendy; Murphy, Katherine A.; Naumenko, Anastasia N.; Nolan, Tony; Novoa, Eva M.; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A.; Pakpour, Nazzy; Papathanos, Philippos A.; Peery, Ashley N.; Povelones, Michael; Prakash, Anil; Price, David P.; Rajaraman, Ashok; Reimer, Lisa J.; Rinker, David C.; Rokas, Antonis; Russell, Tanya L.; Sagnon, N'Fale; Sharakhova, Maria V.; Shea, Terrance; Simão, Felipe A.; Simard, Frederic; Slotman, Michel A.; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J.; Thomas, Gregg W.C.; Tojo, Marta; Topalis, Pantelis; Tubio, José M.C.; Unger, Maria F.; Vontas, John; Walton, Catherine; Wilding, Craig S.; Willis, Judith H.; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M.; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K.; Collins, Frank H.; Cornman, Robert S.; Crisanti, Andrea; Donnelly, Martin J.; Emrich, Scott J.; Fontaine, Michael C.; Gelbart, William; Hahn, Matthew W.; Hansen, Immo A.; Howell, Paul I.; Kafatos, Fotis C.; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A.T.; Ribeiro, José M.; Riehle, Michael A.; Sharakhov, Igor V.; Tu, Zhijian; Zwiebel, Laurence J.; Besansky, Nora J.

2015-01-01

Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover, but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. PMID:25554792

Resource allocation in offspring provisioning: An evaluation of the conditions favoring the evolution of matrotrophy

USGS Publications Warehouse

Trexler, Joel C.; DeAngelis, Donald L.

2003-01-01

We used analytic and simulation models to determine the ecological conditions favoring evolution of a matrotrophic fish from a lecithotrophic ancestor given a complex set of trade‐offs. Matrotrophy is the nourishment of viviparous embryos by resources provided between fertilization and parturition, while lecithotrophy describes embryo nourishment provided before fertilization. In fishes and reptiles, embryo nourishment encompasses a continuum from solely lecithotrophic to primarily matrotrophic. Matrotrophy has evolved independently from lecithotrophic ancestors many times in many groups. We assumed matrotrophy increased the number of offspring a viviparous female could gestate and evaluated conditions of food availability favoring lecithotrophy or matrotrophy. The matrotrophic strategy was superior when food resources exceeded demand during gestation but at a risk of overproduction and reproductive failure if food intake was limited. Matrotrophic females were leaner during gestation than lecithotrophic females, yielding shorter life spans. Our models suggest that matrotrophic embryo nourishment evolved in environments with high food availability, consistently exceeding energy requirements for maintaining relatively large broods. Embryo abortion with some resorption of invested energy is a necessary preadaptation to the evolution of matrotrophy. Future work should explore trade‐offs of age‐specific mortality and reproductive output for females maintaining different levels of fat storage during gestation.

Ageing in a eusocial insect: molecular and physiological characteristics of life span plasticity in the honey bee

PubMed Central

Münch, D.; Amdam, G. V.; Wolschin, F.

2008-01-01

Summary Commonly held views assume that ageing, or senescence, represents an inevitable, passive, and random decline in function that is strongly linked to chronological age. In recent years, genetic intervention of life span regulating pathways, for example, in Drosophila as well as case studies in non-classical animal models, have provided compelling evidence to challenge these views. Rather than comprehensively revisiting studies on the established genetic model systems of ageing, we here focus on an alternative model organism with a wild type (unselected genotype) characterized by a unique diversity in longevity – the honey bee. Honey bee (Apis mellifera) life span varies from a few weeks to more than 2 years. This plasticity is largely controlled by environmental factors. Thereby, although individuals are closely related genetically, distinct life histories can emerge as a function of social environmental change. Another remarkable feature of the honey bee is the occurrence of reverted behavioural ontogeny in the worker (female helper) caste. This behavioural peculiarity is associated with alterations in somatic maintenance functions that are indicative of reverted senescence. Thus, although intraspecific variation in organismal life span is not uncommon, the honey bee holds great promise for gaining insights into regulatory pathways that can shape the time-course of ageing by delaying, halting or even reversing processes of senescence. These aspects provide the setting of our review. We will highlight comparative findings from Drosophila melanogaster and Caenorhabditis elegans in particular, and focus on knowledge spanning from molecular- to behavioural-senescence to elucidate how the honey bee can contribute to novel insights into regulatory mechanisms that underlie plasticity and robustness or irreversibility in ageing. PMID:18728759

Ageing in a eusocial insect: molecular and physiological characteristics of life span plasticity in the honey bee.

PubMed

Münch, D; Amdam, G V; Wolschin, F

2008-01-01

Commonly held views assume that ageing, or senescence, represents an inevitable, passive, and random decline in function that is strongly linked to chronological age. In recent years, genetic intervention of life span regulating pathways, for example, in Drosophila as well as case studies in non-classical animal models, have provided compelling evidence to challenge these views.Rather than comprehensively revisiting studies on the established genetic model systems of ageing, we here focus on an alternative model organism with a wild type (unselected genotype) characterized by a unique diversity in longevity - the honey bee.Honey bee (Apis mellifera) life span varies from a few weeks to more than 2 years. This plasticity is largely controlled by environmental factors. Thereby, although individuals are closely related genetically, distinct life histories can emerge as a function of social environmental change.Another remarkable feature of the honey bee is the occurrence of reverted behavioural ontogeny in the worker (female helper) caste. This behavioural peculiarity is associated with alterations in somatic maintenance functions that are indicative of reverted senescence. Thus, although intraspecific variation in organismal life span is not uncommon, the honey bee holds great promise for gaining insights into regulatory pathways that can shape the time-course of ageing by delaying, halting or even reversing processes of senescence. These aspects provide the setting of our review.We will highlight comparative findings from Drosophila melanogaster and Caenorhabditis elegans in particular, and focus on knowledge spanning from molecular- to behavioural-senescence to elucidate how the honey bee can contribute to novel insights into regulatory mechanisms that underlie plasticity and robustness or irreversibility in ageing.

Differential longitudinal changes in cortical thickness, surface area and volume across the adult life span: regions of accelerating and decelerating change.

PubMed

Storsve, Andreas B; Fjell, Anders M; Tamnes, Christian K; Westlye, Lars T; Overbye, Knut; Aasland, Hilde W; Walhovd, Kristine B

2014-06-18

Human cortical thickness and surface area are genetically independent, emerge through different neurobiological events during development, and are sensitive to different clinical conditions. However, the relationship between changes in the two over time is unknown. Additionally, longitudinal studies have almost invariably been restricted to older adults, precluding the delineation of adult life span trajectories of change in cortical structure. In this longitudinal study, we investigated changes in cortical thickness, surface area, and volume after an average interval of 3.6 years in 207 well screened healthy adults aged 23-87 years. We hypothesized that the relationships among metrics are dynamic across the life span, that the primary contributor to cortical volume reductions in aging is cortical thinning, and that magnitude of change varies with age and region. Changes over time were seen in cortical area (mean annual percentage change [APC], -0.19), thickness (APC, -0.35), and volume (APC, -0.51) in most regions. Volume changes were primarily explained by changes in thickness rather than area. A negative relationship between change in thickness and surface area was found across several regions, where more thinning was associated with less decrease in area, and vice versa. Accelerating changes with increasing age was seen in temporal and occipital cortices. In contrast, decelerating changes were seen in prefrontal and anterior cingulate cortices. In conclusion, a dynamic relationship between cortical thickness and surface area changes exists throughout the adult life span. The mixture of accelerating and decelerating changes further demonstrates the importance of studying these metrics across the entire adult life span. Copyright © 2014 the authors 0270-6474/14/348488-11$15.00/0.

Inducible knockdown of pregnancy-associated plasma protein-A gene expression in adult female mice extends life span.

PubMed

Bale, Laurie K; West, Sally A; Conover, Cheryl A

2017-08-01

Pregnancy-associated plasma protein-A (PAPP-A) knockout (KO) mice, generated through homologous recombination in embryonic stem cells, have a significantly increased lifespan compared to wild-type littermates. However, it is unknown whether this longevity advantage would pertain to PAPP-A gene deletion in adult animals. In the present study, we used tamoxifen (Tam)-inducible Cre recombinase-mediated excision of the floxed PAPP-A (fPAPP-A) gene in mice at 5 months of age. fPAPP-A mice, which were either positive (pos) or negative (neg) for Tam-Cre, received Tam treatment with quarterly boosters. Only female mice could be used with this experimental design. fPAPP-A/neg and fPAPP-A/pos mice had similar weights at the start of the experiment and showed equivalent weight gain. We found that fPAPP-A/pos mice had a significant extension of life span (P = 0.005). The median life span was increased by 21% for fPAPP-A/pos compared to fPAPP-A/neg mice. Analysis of mortality in life span quartiles indicated that the proportion of deaths of fPAPP-A/pos mice were lower than fPAPP-A/neg mice at young adult ages (P = 0.002 for 601-800 days) and higher than fPAPP-A/neg mice at older ages (P = 0.004 for >1000 days). Thus, survival curves and age-specific mortality indicate that female mice with knockdown of PAPP-A gene expression as adults have an extended healthy life span. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Dietary supplementation with Lovaza and krill oil shortens the life span of long-lived F1 mice.

PubMed

Spindler, Stephen R; Mote, Patricia L; Flegal, James M

2014-06-01

Marine oils rich in ω-3 polyunsaturated fatty acids have been recommended as a preventive treatment for patients at risk for cardiovascular diseases. These oils also are the third most consumed dietary supplement in the USA. However, evidence for their health benefits is equivocal. We tested the daily, isocaloric administration of krill oil (1.17 g oil/kg diet) and Lovaza (Omacor; 4.40 g/kg diet), a pharmaceutical grade fish oil, beginning at 12 months of age, on the life span and mortality-related pathologies of long-lived, male, B6C3F1 mice. The oils were incorporated into the chemically defined American Institute of Nutrition (AIN)-93 M diet. An equivalent volume of soybean oil was removed. Krill oil was 3 % and Lovaza 11 % of the oil in the diets. When their effects were analyzed together, the marine oils significantly shortened life span by 6.6 % (P = 0.0321; log-rank test) relative to controls. Individually, Lovaza and krill oil non-significantly shortened median life span by 9.8 and 4.7 %, respectively. Lovaza increased the number of enlarged seminal vesicles (7.1-fold). Lovaza and krill oil significantly increased lung tumors (4.1- and 8.2-fold) and hemorrhagic diathesis (3.9- and 3.1-fold). Analysis of serum from treated mice found that Lovaza slightly increased blood urea nitrogen, while krill oil modestly increased bilirubin, triglycerides, and blood glucose levels. Taken together, the results do not support the idea that the consumption of isolated ω-3 fatty acid-rich oils will increase the life span or health of initially healthy individuals.

A Modelling Study for Predicting Life of Downhole Tubes Considering Service Environmental Parameters and Stress

PubMed Central

Zhao, Tianliang; Liu, Zhiyong; Du, Cuiwei; Hu, Jianpeng; Li, Xiaogang

2016-01-01

A modelling effort was made to try to predict the life of downhole tubes or casings, synthetically considering the effect of service influencing factors on corrosion rate. Based on the discussed corrosion mechanism and corrosion processes of downhole tubes, a mathematic model was established. For downhole tubes, the influencing factors are environmental parameters and stress, which vary with service duration. Stress and the environmental parameters including water content, partial pressure of H2S and CO2, pH value, total pressure and temperature, were considered to be time-dependent. Based on the model, life-span of an L80 downhole tube in oilfield Halfaya, an oilfield in Iraq, was predicted. The results show that life-span of the L80 downhole tube in Halfaya is 247 months (approximately 20 years) under initial stress of 0.1 yield strength and 641 months (approximately 53 years) under no initial stress, which indicates that an initial stress of 0.1 yield strength will reduce the life-span by more than half. PMID:28773872

Evolutionary heritage influences Amazon tree ecology.

PubMed

Coelho de Souza, Fernanda; Dexter, Kyle G; Phillips, Oliver L; Brienen, Roel J W; Chave, Jerome; Galbraith, David R; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Aymard C, Gerardo A; Baraloto, Christopher; Barroso, Jorcely G; Bonal, Damien; Boot, Rene G A; Camargo, José L C; Comiskey, James A; Valverde, Fernando Cornejo; de Camargo, Plínio B; Di Fiore, Anthony; Elias, Fernando; Erwin, Terry L; Feldpausch, Ted R; Ferreira, Leandro; Fyllas, Nikolaos M; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N; Killeen, Timothy J; Laurance, William F; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S; Marimon-Junior, Ben H; Mendoza, Casimiro; Morandi, Paulo; Neill, David A; Vargas, Percy Núñez; Oliveira, Edmar A; Lenza, Eddie; Palacios, Walter A; Peñuela-Mora, Maria C; Pipoly, John J; Pitman, Nigel C A; Prieto, Adriana; Quesada, Carlos A; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M F; van der Meer, Peter J; Vasquez, Rodolfo V; Vieira, Simone A; Vilanova, Emilio; Vos, Vincent A; Wang, Ophelia; Young, Kenneth R; Zagt, Roderick J; Baker, Timothy R

2016-12-14

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. © 2016 The Authors.

High adult mortality among Hiwi hunter-gatherers: implications for human evolution.

PubMed

Hill, Kim; Hurtado, A M; Walker, R S

2007-04-01

Extant apes experience early sexual maturity and short life spans relative to modern humans. Both of these traits and others are linked by life-history theory to mortality rates experienced at different ages by our hominin ancestors. However, currently there is a great deal of debate concerning hominin mortality profiles at different periods of evolutionary history. Observed rates and causes of mortality in modern hunter-gatherers may provide information about Upper Paleolithic mortality that can be compared to indirect evidence from the fossil record, yet little is published about causes and rates of mortality in foraging societies around the world. To our knowledge, interview-based life tables for recent hunter-gatherers are published for only four societies (Ache, Agta, Hadza, and Ju/'hoansi). Here, we present mortality data for a fifth group, the Hiwi hunter-gatherers of Venezuela. The results show comparatively high death rates among the Hiwi and highlight differences in mortality rates among hunter-gatherer societies. The high levels of conspecific violence and adult mortality in the Hiwi may better represent Paleolithic human demographics than do the lower, disease-based death rates reported in the most frequently cited forager studies.

Evolutionary heritage influences Amazon tree ecology

PubMed Central

Coelho de Souza, Fernanda; Dexter, Kyle G.; Phillips, Oliver L.; Brienen, Roel J. W.; Chave, Jerome; Galbraith, David R.; Lopez Gonzalez, Gabriela; Monteagudo Mendoza, Abel; Pennington, R. Toby; Poorter, Lourens; Alexiades, Miguel; Álvarez-Dávila, Esteban; Andrade, Ana; Aragão, Luis E. O. C.; Araujo-Murakami, Alejandro; Arets, Eric J. M. M.; Aymard C, Gerardo A.; Baraloto, Christopher; Barroso, Jorcely G.; Bonal, Damien; Boot, Rene G. A.; Camargo, José L. C.; Comiskey, James A.; Valverde, Fernando Cornejo; de Camargo, Plínio B.; Di Fiore, Anthony; Erwin, Terry L.; Feldpausch, Ted R.; Ferreira, Leandro; Fyllas, Nikolaos M.; Gloor, Emanuel; Herault, Bruno; Herrera, Rafael; Higuchi, Niro; Honorio Coronado, Eurídice N.; Killeen, Timothy J.; Laurance, William F.; Laurance, Susan; Lloyd, Jon; Lovejoy, Thomas E.; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Marimon-Junior, Ben H.; Mendoza, Casimiro; Morandi, Paulo; Neill, David A.; Vargas, Percy Núñez; Oliveira, Edmar A.; Lenza, Eddie; Palacios, Walter A.; Peñuela-Mora, Maria C.; Pipoly, John J.; Pitman, Nigel C. A.; Prieto, Adriana; Quesada, Carlos A.; Ramirez-Angulo, Hirma; Rudas, Agustin; Ruokolainen, Kalle; Salomão, Rafael P.; Silveira, Marcos; ter Steege, Hans; Thomas-Caesar, Raquel; van der Hout, Peter; van der Heijden, Geertje M. F.; van der Meer, Peter J.; Vasquez, Rodolfo V.; Vieira, Simone A.; Vilanova, Emilio; Vos, Vincent A.; Wang, Ophelia; Young, Kenneth R.; Zagt, Roderick J.; Baker, Timothy R.

2016-01-01

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change. PMID:27974517

Stem Cell Models: A Guide to Understand and Mitigate Aging?

PubMed

Brunauer, Regina; Alavez, Silvestre; Kennedy, Brian K

2017-01-01

Aging is studied either on a systemic level using life span and health span of animal models, or on the cellular level using replicative life span of yeast or mammalian cells. While useful in identifying general and conserved pathways of aging, both approaches provide only limited information about cell-type specific causes and mechanisms of aging. Stem cells are the regenerative units of multicellular life, and stem cell aging might be a major cause for organismal aging. Using the examples of hematopoietic stem cell aging and human pluripotent stem cell models, we propose that stem cell models of aging are valuable for studying tissue-specific causes and mechanisms of aging and can provide unique insights into the mammalian aging process that may be inaccessible in simple model organisms. © 2016 S. Karger AG, Basel.

Food-derived sensory cues modulate longevity via distinct neuroendocrine insulin-like peptides

PubMed Central

Artan, Murat; Jeong, Dae-Eun; Lee, Dongyeop; Kim, Young-Il; Son, Heehwa G.; Husain, Zahabiya; Kim, Jinmahn; Altintas, Ozlem; Kim, Kyuhyung; Alcedo, Joy; Lee, Seung-Jae V.

2016-01-01

Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans’ life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs. PMID:27125673

Studying the replicative life span of yeast cells.

PubMed

Sinclair, David A

2013-01-01

The budding yeast Saccharomyces cerevisiae is a useful model for elucidating the pathways that control life span and the influence of environmental factors, such as calorie restriction (CR). For 75 years, CR has been studied for its ability to delay diseases of aging in mammals, from cancer to cardiovascular disease (McCay et al., Nutr Rev 33:241-243, 1975). In many other species, reducing calorie intake extends life span, including unicellular organisms (Jiang et al., FASEB J 14:2135-2137, 2000; Lin et al., Science 289:2126-2128, 2000), invertebrates (Rogina and Helfand, Proc Natl Acad Sci U S A 101:15998-16003, 2004), and rodents (Martín-Montalvo et al., Oncogene 30:505-520, 2011). Here we describe how to calorically restrict yeast cells, the methods used to determine the replicative life span (RLS) of budding yeast cells, how to selectively kill daughter cells using the mother enrichment program (MEP), how to measure recombination frequency at the rDNA locus, how to isolate large quantities of old cells, and how to analyze the circular forms of DNA known as extrachromosomal rDNA circles (ERCs), a cause of aging in S. cerevisiae (Petes, Cell 19:765-774, 1980; Sinclair and Guarente, Cell 91:1033-1042, 1997; Defossez et al., Mol Cell 3:447-455, 1999).

Fragmentation, Fusion, and Genetic Homogeneity in a Calcareous Sponge (Porifera, Calcarea).

PubMed

Padua, André; Leocorny, Pedro; Custódio, Márcio Reis; Klautau, Michelle

2016-06-01

Sessile marine invertebrates living on hard substrata usually present strategies such as size variations, longer life spans, fragmentation and fusion to occupy and compete for space. Calcareous sponges are usually small and short-lived, and some species are known to undergo frequent fragmentation and fusion events. However, whether fusion occurs only between genetically identical individuals remains unclear. We investigated the occurrence of chimaeras in the calcareous sponge Clathrina aurea by following the dynamics of fragmentation and fusion of 66 individuals in the field for up to 18 months and determined size variations and the life span of each individual. Microsatellites were used to determine whether fusion events occur among genetically different individuals. Growth and shrinkage of individuals were frequently observed, showing that size cannot be associated with age in C. aurea. The life span of the species ranged from 1 to 16 months (mean: 4.7 months). Short life spans and variable growth rates have been observed in other species of the class Calcarea. Fragmentation and fusion events were observed, but fusion events always occurred between genetically identical individuals, as has been suggested by graft experiments in adult Demospongiae and other Calcarea. These results suggest that at least C. aurea adults may have some mechanism to avoid chimaerism. © 2016 Wiley Periodicals, Inc.

Implication of Ca2+ in the regulation of replicative life span of budding yeast.

PubMed

Tsubakiyama, Ryohei; Mizunuma, Masaki; Gengyo, Anri; Yamamoto, Josuke; Kume, Kazunori; Miyakawa, Tokichi; Hirata, Dai

2011-08-19

In eukaryotic cells, Ca(2+)-triggered signaling pathways are used to regulate a wide variety of cellular processes. Calcineurin, a highly conserved Ca(2+)/calmodulin-dependent protein phosphatase, plays key roles in the regulation of diverse biological processes in organisms ranging from yeast to humans. We isolated a mutant of the SIR3 gene, implicated in the regulation of life span, as a suppressor of the Ca(2+) sensitivity of zds1Δ cells in the budding yeast Saccharomyces cerevisiae. Therefore, we investigated a relationship between Ca(2+) signaling and life span in yeast. Here we show that Ca(2+) affected the replicative life span (RLS) of yeast. Increased external and intracellular Ca(2+) levels caused a reduction in their RLS. Consistently, the increase in calcineurin activity by either the zds1 deletion or the constitutively activated calcineurin reduced RLS. Indeed, the shortened RLS of zds1Δ cells was suppressed by the calcineurin deletion. Further, the calcineurin deletion per se promoted aging without impairing the gene silencing typically observed in short-lived sir mutants, indicating that calcineurin plays an important role in a regulation of RLS even under normal growth condition. Thus, our results indicate that Ca(2+) homeostasis/Ca(2+) signaling are required to regulate longevity in budding yeast.

Intermittent Administration of Rapamycin Extends the Life Span of Female C57BL/6J Mice.

PubMed

Arriola Apelo, Sebastian I; Pumper, Cassidy P; Baar, Emma L; Cummings, Nicole E; Lamming, Dudley W

2016-07-01

Inhibition of the mTOR (mechanistic target of rapamycin) signaling pathway by the FDA-approved drug rapamycin promotes life span in numerous model organisms and delays age-related disease in mice. However, the utilization of rapamycin as a therapy for age-related diseases will likely prove challenging due to the serious metabolic and immunological side effects of rapamycin in humans. We recently identified an intermittent rapamycin treatment regimen-2mg/kg administered every 5 days-with a reduced impact on glucose homeostasis and the immune system as compared with chronic treatment; however, the ability of this regimen to extend life span has not been determined. Here, we report for the first time that an intermittent rapamycin treatment regimen starting as late as 20 months of age can extend the life span of female C57BL/6J mice. Our work demonstrates that the anti-aging potential of rapamycin is separable from many of its negative side effects and suggests that carefully designed dosing regimens may permit the safer use of rapamycin and its analogs for the treatment of age-related diseases in humans. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxygenation of Earth's atmosphere and its impact on the evolution of nitrogen-based metabolisms

NASA Astrophysics Data System (ADS)

Papineau, D.; Mojzsis, S. J.

2002-12-01

The evolution of metabolic pathways is closely linked to the evolution of the redox state of the terrestrial atmosphere. Nitrogen has been an essential biological element since the emergence of life when reduced nitrogen compounds (e.g. ammonia) were utilized in the prebiotic synthesis of proteins and nucleic acids. The nitrogen isotopic composition of sediments has been used to trace the origin of sedimentary organic matter in the rock record. Nitrogen is therefore suitable as a biosignature to trace the emergence of life on Earth or other planetary bodies as well as to follow the subsequent evolution of the biosphere in response to global redox changes. Evidence is strong that biological nitrogen fixation evolved very early in the history of life. The Last Common Ancestor (LCA) on Earth was most likely capable of nitrogen fixation as seen from the phylogenetic distribution of nitrogen-fixing organisms in both the domains of Bacteria and Archaea. Phylogenetic trees plotted with nitrogen-fixing gene (Nif) sequences from lineages of Bacteria and Archaea suggest that the Nif genes originated in a common ancestor of the two domains. Other phylogenetic analyses have also demonstrated that the paralogous duplication of the nifDK and nifEN operons, central to nitrogen fixation, predated the divergence of Archaea from Bacteria and therefore occurred prior to the emergence of the LCA. Although the same may be true for denitrification, this metabolic pathway probably did not become dominant until atmospheric pO2 increased between ~2.4 to 1.9 Ga during the Great Oxygenation Event (GOE). Recent work has shown a general depletion in 15N content of Archean (pre-2.5 Ga) relative to Phanerozoic (<540 Ma) kerogens. Studies have shown that the distribution of the δ15N values in kerogens shift from negative values in the Early Archean (from -6 to +6‰ with an average near 0‰ ) to approximately contemporary positive values (from +2 to +10‰ with an average at +6‰ ) by the Early Proterozoic. In the anoxic Archean atmosphere, the nitrogen cycle must have been different and the instability of oxidized nitrogen species such as NO3- under low pO2 must have limited its availability. Therefore nitrogen fixation probably was the dominant nitrogen-based metabolic pathway during the Archean until the rise of oxygen in the atmosphere in the Early Proterozoic, which resulted in more favorable conditions for denitrification to become the dominant nitrogen-based metabolism. Stable isotopic ratios can be used to detect denitrification (which positively fractionates δ15N) and nitrogen fixation (which negatively fractionates δ15N) in K+-containing minerals such as biotite and muscovite. In an effort to characterize the transition from the essentially anoxic Archean atmosphere to the modern oxidizing atmosphere, we are investigating sedimentary rocks spanning 2.4 to 1.9 Ga from Rovaniemi, Finland. Structural NH4+ in minerals is characterized by μFTIR spectroscopy. Our new μFTIR measurements of Early Proterozoic metasediments spanning the 2.4 - 1.9 Ga time interval (and focused on the well-represented 2.2 - 1.9 Ga time interval from Rovaniemi) provide a high-resolution record of ammonium content during the GOE as a prelude to future detailed δ15N measurements by laser mass spectrometry. This work traces the evolution of nitrogen fixation in the biosphere, its response to changes in global redox and provides a tool for the investigation of biosignatures in samples returned from other ancient planetary surfaces.

Shorter Life Span of Microorganisms and Plants as a Consequence of Shielded Magnetic Environment

NASA Astrophysics Data System (ADS)

Dobrota, C.; Piso, I. M.; Bathory, D.

The geomagnetic field is an essential environmental factor for life and health on this planet. In order to survey how magnetic fields affect the life span and the nitrogenase (an iron-sulphur enzyme) activity of Azotobacter chroococcum as well as the life span, the main organic synthesis and the water balance of plants (22 species), the biological tests were incubated under shielded magnetic field and also in normal geo-magnetic environment. The shielding level was about 10-6 of the terrestrial magnetic field.Life cycles of all organisms require the co-ordinated control of a complex set of interlocked physiological processes and metabolic pathways. Such processes are likely to be regulated by a large number of genes. Our researches suggest that the main point in biological structures, which seems to be affected by the low magnetic environment, is the water molecule. Magnetic field induces a molecular alignment. Under shielded conditions, unstructured water molecules with fewer hydrogen bonds, which are producing a more reactive environment, are occurring. As compared to control, the life span of both microorganisms and plants was shorter in shielded environment. A higher nitrogenase affinity for the substrate was recorded in normal geo-magnetic field compared to low magnetic field. The synthesis of carbohydrates, lipids, proteins and enzymes was modified under experimental conditions. The stomatal conductance was higher between 158 and 300% in shielded environment indicating an important water loss from the plant cells.Our results support the idea that the shielded magnetic environment induces different reactions depending on the time of exposure and on the main metabolic pathways of the cells.

Human Development, Human Evolution.

ERIC Educational Resources Information Center

Smillie, David

One of the truly remarkable events in human evolution is the unprecedented increase in the size of the brain of "Homo" over a brief span of 2 million years. It would appear that some significant selective pressure or opportunity presented itself to this branch of the hominid line and caused a rapid increase in the brain, introducing a…

Life-span development of self-esteem and its effects on important life outcomes.

PubMed

Orth, Ulrich; Robins, Richard W; Widaman, Keith F

2012-06-01

We examined the life-span development of self-esteem and tested whether self-esteem influences the development of important life outcomes, including relationship satisfaction, job satisfaction, occupational status, salary, positive and negative affect, depression, and physical health. Data came from the Longitudinal Study of Generations. Analyses were based on 5 assessments across a 12-year period of a sample of 1,824 individuals ages 16 to 97 years. First, growth curve analyses indicated that self-esteem increases from adolescence to middle adulthood, reaches a peak at about age 50 years, and then decreases in old age. Second, cross-lagged regression analyses indicated that self-esteem is best modeled as a cause rather than a consequence of life outcomes. Third, growth curve analyses, with self-esteem as a time-varying covariate, suggested that self-esteem has medium-sized effects on life-span trajectories of affect and depression, small to medium-sized effects on trajectories of relationship and job satisfaction, a very small effect on the trajectory of health, and no effect on the trajectory of occupational status. These findings replicated across 4 generations of participants--children, parents, grandparents, and their great-grandparents. Together, the results suggest that self-esteem has a significant prospective impact on real-world life experiences and that high and low self-esteem are not mere epiphenomena of success and failure in important life domains. 2012 APA, all rights reserved

Nup100 regulates Saccharomyces cerevisiae replicative life span by mediating the nuclear export of specific tRNAs

PubMed Central

Lord, Christopher L.; Ospovat, Ophir; Wente, Susan R.

2017-01-01

Nuclear pore complexes (NPCs), which are composed of nucleoporins (Nups) and regulate transport between the nucleus and cytoplasm, significantly impact the replicative life span (RLS) of Saccharomyces cerevisiae. We previously reported that deletion of the nonessential gene NUP100 increases RLS, although the molecular basis for this effect was unknown. In this study, we find that nuclear tRNA accumulation contributes to increased longevity in nup100Δ cells. Fluorescence in situ hybridization (FISH) experiments demonstrate that several specific tRNAs accumulate in the nuclei of nup100Δ mutants. Protein levels of the transcription factor Gcn4 are increased when NUP100 is deleted, and GCN4 is required for the elevated life spans of nup100Δ mutants, similar to other previously described tRNA export and ribosomal mutants. Northern blots indicate that tRNA splicing and aminoacylation are not significantly affected in nup100Δ cells, suggesting that Nup100 is largely required for nuclear export of mature, processed tRNAs. Distinct tRNAs accumulate in the nuclei of nup100Δ and msn5Δ mutants, while Los1-GFP nucleocytoplasmic shuttling is unaffected by Nup100. Thus, we conclude that Nup100 regulates tRNA export in a manner distinct from Los1 or Msn5. Together, these experiments reveal a novel Nup100 role in the tRNA life cycle that impacts the S. cerevisiae life span. PMID:27932586

Relationships of leaf dark respiration to leaf nitrogen, specific leaf area and leaf life-span: a test across biomes and functional groups

Treesearch

Peter B. Reich; Michael B. Walters; David S. Ellsworth; [and others; [Editor’s note: James M.. Vose is the SRS co-author for this publication.

1998-01-01

Based on prior evidence of coordinated multiple leaf trait scaling, the authors hypothesized that variation among species in leaf dark respiration rate (Rd) should scale with variation in traits such as leaf nitrogen (N), leaf life-span, specific leaf area (SLA), and net photosynthetic capacity (Amax). However, it is not known whether such scaling, if it exists, is...

[Effect of pineal peptide on parameters of the biological age and life span in mice].

PubMed

Anisimov, V N; Khavinson, V Kh; Zavarzina, N Iu; Zabezhinskiĭ, M A; Zimina, O A; Popovich, I G; Shtylik, A V; Arutiunian, A V; Oparina, T I; Prokopenko, V M

2001-01-01

Female CBA mice were injected with s.c. synthetic tetrapeptide Epithalon from a 6-month age until death. The drug failed to affect the body weight or food consumption, physical activity or behavioural parameters. However, it slowed down the age-related switching off of the estrus function, decreased body temperature, decelerated free redical processes, prolonged the mice life span with an accompanying drop in spontaneous tumour incidence.

Proceedings of the Astrobiology Science Conference 2010. Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond

NASA Technical Reports Server (NTRS)

2010-01-01

The Program of the 2010 Astrobiology Science Conference: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond, included sessions on: 50 Years of Exobiology and Astrobiology: Greatest Hits; Extraterrestrial Molecular Evolution and Pre-Biological Chemistry: From the Interstellar Medium to the Solar System I; Human Exploration, Astronaut Health; Diversity in Astrobiology Research and Education; Titan: Past, Present, and Future; Energy Flow in Microbial Ecosystems; Extraterrestrial Molecular Evolution and Prebiological Chemistry: From the Interstellar Medium to the Solar System II; Astrobiology in Orbit; Astrobiology and Interdisciplinary Communication; Science from Rio Tinto: An Acidic Environment; Can We Rule Out Spontaneous Generation of RNA as the Key Step in the Origin of Life?; How Hellish Was the Hadean Earth?; Results from ASTEP and Other Astrobiology Field Campaigns I; Prebiotic Evolution: From Chemistry to Life I; Adaptation of Life in Hostile Space Environments; Extrasolar Terrestrial Planets I: Formation and Composition; Collaborative Tools and Technology for Astrobiology; Results from ASTEP and Other Astrobiology Field Campaigns II; Prebiotic Evolution: From Chemistry to Life II; Survival, Growth, and Evolution of Microrganisms in Model Extraterrestrial Environments; Extrasolar Terrestrial Planets II: Habitability and Life; Planetary Science Decadal Survey Update; Astrobiology Research Funding; Bioessential Elements Through Space and Time I; State of the Art in Life Detection; Terrestrial Evolution: Implications for the Past, Present, and Future of Life on Earth; Psychrophiles and Polar Environments; Life in Volcanic Environments: On Earth and Beyond; Geochronology and Astrobiology On and Off the Earth; Bioessential Elements Through Space and Time II; Origins and Evolution of Genetic Systems; Evolution of Advanced Life; Water-rich Asteroids and Moons: Composition and Astrobiological Potential; Impact Events and Evolution; A Warm, Wet Mars?; Titan Versus Europa - Potential for Astrobiology; Habitability Potential of Mars; Biosignatures: Tools and Development I; Origins of Molecular Asymmetry, Homochirality, and Life Detection; Deserts and Evaporite Basins and Associated Microbialite Systems; Ancient Life and Synthetic Biology: Crossroad of the Past and Future; Biosignatures: Tools and Development II; Free Oxygen: Proxies, Causes, and Consequences; Life in Modern Microbialite Systems - Function and Adaptation; Hydrothermal Systems and Organosynthesis Processes: Origin and Evolution of Life; Where Should We Go on Mars to Seek Signs of Life?; Search for Intelligent Life I. Innovative SETI Observing Programs and Future Directions; Integrating Astrobiology Research Across and Beyond the Community; Education in Astrobiology in K-12; Search for Intelligent Life II. Global Engagement and Interstellar Message Construction; Poster sessions included: Extraterrestrial Molecular Evolution and Pre-Biological Chemistry; Prebiotic Evolution: From Chemistry to Life; RNA World; Terrestrial Evolution: Implications for the Past, Present, and Future of Life on Earth; Hydrothermal Systems and Organosynthesis Processes: Origin and Evolution of Life; Virology and Astrobiology; Horizontal Genetic Transfer and Properties of Ancestral Organisms; Life in Volcanic Environments: On Earth and Beyond; Impact Events and Evolution; Evolution of Advanced Life; Evolution of Intelligent Life; Education in Astrobiology in K-12; Origins of Molecular Asymmetry, Homochirality, and Life Detection; Astrobiology and Interdisciplinary Communication; Diversity in Astrobiology Research and Education; Integrating Astrobiology Research Across and Beyond the Community; Policy and Societal Issues: Dealing with Potential Bumps in the Astrobiology Road Ahead; Results from ASTEP and Other Astrobiology Field Campaigns; Energy Flow in Microbial Ecosystems; Psychrophiles and Polar Environments; Deserts and Evaporite Basins and Associated Microbialite stems; Life in Modern Microbialite Systems - Function and Adaptation; Free Oxygen: Proxies, Causes, and Consequences; Bioessential Elements Through Space and Time; Water-rich Asteroids and Moons: Composition and Astrobiological Potential; Biosignatures: Tools and Developments; Robotics and Instrumentation for Astrobiology; State of the Art in Life Detection; Astrobiology in Orbit; Survival, Growth, and Evolution of Microrganisms in Model Extraterrestrial Evolution; Search for Intelligent Life; Habitability Potential of Mars; How and Where Should We Seek Signs of Life on Mars?; Titan: Past, Present, and Future; Extrasolar Terrestrial Planets: Formation, Composition, Diversity, Habitability and Life; Human Exploration, Astronaut Health; Science from Rio Tinto: An Acidic Environment and Adaptation of Life in Hostile Space Environments;

Spatial abilities across the adult life span.

PubMed

Borella, Erika; Meneghetti, Chiara; Ronconi, Lucia; De Beni, Rossana

2014-02-01

The study investigates age-related effects across the adult life span on spatial abilities (testing subabilities based on a distinction between spatial visualization, mental rotation, and perspective taking) and spatial self-assessments. The sample consisted of 454 participants (223 women and 231 men) from 20 to 91 years of age. Results showed nonlinear age-related effects for spatial visualization and perspective taking but linear effects for mental rotation; few or no age-related effects were found for spatial self-assessments. Working memory accounted for only a small proportion of the variance in all spatial tasks and had no effect on spatial self-assessments. Overall, our findings suggest that the influence of age on spatial skills across the adult life span is considerable, but the effects of age change as a function of the spatial task considered, and the effect on spatial self-assessment is more marginal.

Food-derived sensory cues modulate longevity via distinct neuroendocrine insulin-like peptides.

PubMed

Artan, Murat; Jeong, Dae-Eun; Lee, Dongyeop; Kim, Young-Il; Son, Heehwa G; Husain, Zahabiya; Kim, Jinmahn; Altintas, Ozlem; Kim, Kyuhyung; Alcedo, Joy; Lee, Seung-Jae V

2016-05-01

Environmental fluctuations influence organismal aging by affecting various regulatory systems. One such system involves sensory neurons, which affect life span in many species. However, how sensory neurons coordinate organismal aging in response to changes in environmental signals remains elusive. Here, we found that a subset of sensory neurons shortens Caenorhabditis elegans' life span by differentially regulating the expression of a specific insulin-like peptide (ILP), INS-6. Notably, treatment with food-derived cues or optogenetic activation of sensory neurons significantly increases ins-6 expression and decreases life span. INS-6 in turn relays the longevity signals to nonneuronal tissues by decreasing the activity of the transcription factor DAF-16/FOXO. Together, our study delineates a mechanism through which environmental sensory cues regulate aging rates by modulating the activities of specific sensory neurons and ILPs. © 2016 Artan et al.; Published by Cold Spring Harbor Laboratory Press.

Caenorhabditis elegans as Model System in Pharmacology and Toxicology: Effects of Flavonoids on Redox-Sensitive Signalling Pathways and Ageing

PubMed Central

Koch, Karoline; Havermann, Susannah; Büchter, Christian

2014-01-01

Flavonoids are secondary plant compounds that mediate diverse biological activities, for example, by scavenging free radicals and modulating intracellular signalling pathways. It has been shown in various studies that distinct flavonoid compounds enhance stress resistance and even prolong the life span of organisms. In the last years the model organism C. elegans has gained increasing importance in pharmacological and toxicological sciences due to the availability of various genetically modified nematode strains, the simplicity of modulating genes by RNAi, and the relatively short life span. Several studies have been performed demonstrating that secondary plant compounds influence ageing, stress resistance, and distinct signalling pathways in the nematode. Here we present an overview of the modulating effects of different flavonoids on oxidative stress, redox-sensitive signalling pathways, and life span in C. elegans introducing the usability of this model system for pharmacological and toxicological research. PMID:24895670

Basic traits predict the prevalence of personality disorder across the life span: the example of psychopathy.

PubMed

Vachon, David D; Lynam, Donald R; Widiger, Thomas A; Miller, Joshua D; McCrae, Robert R; Costa, Paul T

2013-05-01

Personality disorders (PDs) may be better understood in terms of dimensions of general personality functioning rather than as discrete categorical conditions. Personality-trait descriptions of PDs are robust across methods and settings, and PD assessments based on trait measures show good construct validity. The study reported here extends research showing that basic traits (e.g., impulsiveness, warmth, straightforwardness, modesty, and deliberation) can re-create the epidemiological characteristics associated with PDs. Specifically, we used normative changes in absolute trait levels to simulate age-related differences in the prevalence of psychopathy in a forensic setting. Results demonstrated that trait information predicts the rate of decline for psychopathy over the life span; discriminates the decline of psychopathy from that of a similar disorder, antisocial PD; and accurately predicts the differential decline of subfactors of psychopathy. These findings suggest that basic traits provide a parsimonious account of PD prevalence across the life span.

daf-16: An HNF-3/forkhead family member that can function to double the life-span of Caenorhabditis elegans.

PubMed

Lin, K; Dorman, J B; Rodan, A; Kenyon, C

1997-11-14

The wild-type Caenorhabditis elegans nematode ages rapidly, undergoing development, senescence, and death in less than 3 weeks. In contrast, mutants with reduced activity of the gene daf-2, a homolog of the insulin and insulin-like growth factor receptors, age more slowly than normal and live more than twice as long. These mutants are active and fully fertile and have normal metabolic rates. The life-span extension caused by daf-2 mutations requires the activity of the gene daf-16. daf-16 appears to play a unique role in life-span regulation and encodes a member of the hepatocyte nuclear factor 3 (HNF-3)/forkhead family of transcriptional regulators. In humans, insulin down-regulates the expression of certain genes by antagonizing the activity of HNF-3, raising the possibility that aspects of this regulatory system have been conserved.

NAD⁺ repletion improves mitochondrial and stem cell function and enhances life span in mice.

PubMed

Zhang, Hongbo; Ryu, Dongryeol; Wu, Yibo; Gariani, Karim; Wang, Xu; Luan, Peiling; D'Amico, Davide; Ropelle, Eduardo R; Lutolf, Matthias P; Aebersold, Ruedi; Schoonjans, Kristina; Menzies, Keir J; Auwerx, Johan

2016-06-17

Adult stem cells (SCs) are essential for tissue maintenance and regeneration yet are susceptible to senescence during aging. We demonstrate the importance of the amount of the oxidized form of cellular nicotinamide adenine dinucleotide (NAD(+)) and its effect on mitochondrial activity as a pivotal switch to modulate muscle SC (MuSC) senescence. Treatment with the NAD(+) precursor nicotinamide riboside (NR) induced the mitochondrial unfolded protein response and synthesis of prohibitin proteins, and this rejuvenated MuSCs in aged mice. NR also prevented MuSC senescence in the mdx (C57BL/10ScSn-Dmd(mdx)/J) mouse model of muscular dystrophy. We furthermore demonstrate that NR delays senescence of neural SCs and melanocyte SCs and increases mouse life span. Strategies that conserve cellular NAD(+) may reprogram dysfunctional SCs and improve life span in mammals. Copyright © 2016, American Association for the Advancement of Science.

Partner preferences across the life span: online dating by older adults.

PubMed

Alterovitz, Sheyna Sears-Roberts; Mendelsohn, Gerald A

2009-06-01

Stereotypes of older adults as withdrawn or asexual fail to recognize that romantic relationships in later life are increasingly common. The authors analyzed 600 Internet personal ads from 4 age groups: 20-34, 40-54, 60-74, and 75+ years. Predictions from evolutionary theory held true in later life, when reproduction is no longer a concern. Across the life span, men sought physical attractiveness and offered status-related information more than women; women were more selective than men and sought status more than men. With age, men desired women increasingly younger than themselves, whereas women desired older men until ages 75 and over, when they sought men younger than themselves. (c) 2009 APA, all rights reserved.

Balancing Life Roles to Achieve Career Happiness and Life Satisfaction.

ERIC Educational Resources Information Center

Peronne, Kristin Marie

2000-01-01

A study guided by Super's Life Span, Life Space approach included a survey of 119 women and 66 men about sacrifices made in life and work roles to achieve balance and satisfaction. Differences in sacrifices and satisfaction were related to the combination of life roles they occupied. (SK)

Second Symposium on Chemical Evolution and the Origin of Life

NASA Technical Reports Server (NTRS)

Devincenzi, D. L. (Editor); model. (Editor)

1986-01-01

Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

Second Symposium on Chemical Evolution and the Origin of Life

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devincenzi, D.L.; Dufour, P.A.

1986-05-01

Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

Opportunistic Mobility Support for Resource Constrained Sensor Devices in Smart Cities

PubMed Central

Granlund, Daniel; Holmlund, Patrik; Åhlund, Christer

2015-01-01

A multitude of wireless sensor devices and technologies are being developed and deployed in cities all over the world. Sensor applications in city environments may include highly mobile installations that span large areas which necessitates sensor mobility support. This paper presents and validates two mechanisms for supporting sensor mobility between different administrative domains. Firstly, EAP-Swift, an Extensible Authentication Protocol (EAP)-based sensor authentication protocol is proposed that enables light-weight sensor authentication and key generation. Secondly, a mechanism for handoffs between wireless sensor gateways is proposed. We validate both mechanisms in a real-life study that was conducted in a smart city environment with several fixed sensors and moving gateways. We conduct similar experiments in an industry-based anechoic Long Term Evolution (LTE) chamber with an ideal radio environment. Further, we validate our results collected from the smart city environment against the results produced under ideal conditions to establish best and real-life case scenarios. Our results clearly validate that our proposed mechanisms can facilitate efficient sensor authentication and handoffs while sensors are roaming in a smart city environment. PMID:25738767

Opportunistic mobility support for resource constrained sensor devices in smart cities.

PubMed

Granlund, Daniel; Holmlund, Patrik; Åhlund, Christer

2015-03-02

A multitude of wireless sensor devices and technologies are being developed and deployed in cities all over the world. Sensor applications in city environments may include highly mobile installations that span large areas which necessitates sensor mobility support. This paper presents and validates two mechanisms for supporting sensor mobility between different administrative domains. Firstly, EAP-Swift, an Extensible Authentication Protocol (EAP)-based sensor authentication protocol is proposed that enables light-weight sensor authentication and key generation. Secondly, a mechanism for handoffs between wireless sensor gateways is proposed. We validate both mechanisms in a real-life study that was conducted in a smart city environment with several fixed sensors and moving gateways. We conduct similar experiments in an industry-based anechoic Long Term Evolution (LTE) chamber with an ideal radio environment. Further, we validate our results collected from the smart city environment against the results produced under ideal conditions to establish best and real-life case scenarios. Our results clearly validate that our proposed mechanisms can facilitate efficient sensor authentication and handoffs while sensors are roaming in a smart city environment.

U.S. Science Teaching and Learning of Evolution: A Critical Review of the Literature 2000-2014

ERIC Educational Resources Information Center

Glaze, Amanda L.; Goldston, M. Jenice

2015-01-01

This critical analysis examined research on evolution in the United States between the years 2000-2014, spanning early classroom implementation of the National Science Education Standards to current research findings. First, we sought to understand how the research literature published between 2000 and 2014 contributed to knowledge of evolution…

The evolution of lethal intergroup violence

PubMed Central

Kelly, Raymond C.

2005-01-01

Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry. PMID:16129826

The evolution of lethal intergroup violence.

PubMed

Kelly, Raymond C

2005-10-25

Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry.

Self-esteem development across the life span: a longitudinal study with a large sample from Germany.

PubMed

Orth, Ulrich; Maes, Jürgen; Schmitt, Manfred

2015-02-01

The authors examined the development of self-esteem across the life span. Data came from a German longitudinal study with 3 assessments across 4 years of a sample of 2,509 individuals ages 14 to 89 years. The self-esteem measure used showed strong measurement invariance across assessments and birth cohorts. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the life span, increasing during adolescence, young adulthood, and middle adulthood, reaching a peak at age 60 years, and then declining in old age. No cohort effects on average levels of self-esteem or on the shape of the trajectory were found. Moreover, the trajectory did not differ across gender, level of education, or for individuals who had lived continuously in West versus East Germany (i.e., the 2 parts of Germany that had been separate states from 1949 to 1990). However, the results suggested that employment status, household income, and satisfaction in the domains of work, relationships, and health contribute to a more positive life span trajectory of self-esteem. The findings have significant implications, because they call attention to developmental stages in which individuals may be vulnerable because of low self-esteem (such as adolescence and old age) and to factors that predict successful versus problematic developmental trajectories. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Diversity and function of bacterial microbiota in the mosquito holobiont

PubMed Central

2013-01-01

Mosquitoes (Diptera: Culicidae) have been shown to host diverse bacterial communities that vary depending on the sex of the mosquito, the developmental stage, and ecological factors. Some studies have suggested a potential role of microbiota in the nutritional, developmental and reproductive biology of mosquitoes. Here, we present a review of the diversity and functions of mosquito-associated bacteria across multiple variation factors, emphasizing recent findings. Mosquito microbiota is considered in the context of possible extended phenotypes conferred on the insect hosts that allow niche diversification and rapid adaptive evolution in other insects. These kinds of observations have prompted the recent development of new mosquito control methods based on the use of symbiotically-modified mosquitoes to interfere with pathogen transmission or reduce the host life span and reproduction. New opportunities for exploiting bacterial function for vector control are highlighted. PMID:23688194

Mosquito genomics. Highly evolvable malaria vectors: the genomes of 16 Anopheles mosquitoes.

PubMed

Neafsey, Daniel E; Waterhouse, Robert M; Abai, Mohammad R; Aganezov, Sergey S; Alekseyev, Max A; Allen, James E; Amon, James; Arcà, Bruno; Arensburger, Peter; Artemov, Gleb; Assour, Lauren A; Basseri, Hamidreza; Berlin, Aaron; Birren, Bruce W; Blandin, Stephanie A; Brockman, Andrew I; Burkot, Thomas R; Burt, Austin; Chan, Clara S; Chauve, Cedric; Chiu, Joanna C; Christensen, Mikkel; Costantini, Carlo; Davidson, Victoria L M; Deligianni, Elena; Dottorini, Tania; Dritsou, Vicky; Gabriel, Stacey B; Guelbeogo, Wamdaogo M; Hall, Andrew B; Han, Mira V; Hlaing, Thaung; Hughes, Daniel S T; Jenkins, Adam M; Jiang, Xiaofang; Jungreis, Irwin; Kakani, Evdoxia G; Kamali, Maryam; Kemppainen, Petri; Kennedy, Ryan C; Kirmitzoglou, Ioannis K; Koekemoer, Lizette L; Laban, Njoroge; Langridge, Nicholas; Lawniczak, Mara K N; Lirakis, Manolis; Lobo, Neil F; Lowy, Ernesto; MacCallum, Robert M; Mao, Chunhong; Maslen, Gareth; Mbogo, Charles; McCarthy, Jenny; Michel, Kristin; Mitchell, Sara N; Moore, Wendy; Murphy, Katherine A; Naumenko, Anastasia N; Nolan, Tony; Novoa, Eva M; O'Loughlin, Samantha; Oringanje, Chioma; Oshaghi, Mohammad A; Pakpour, Nazzy; Papathanos, Philippos A; Peery, Ashley N; Povelones, Michael; Prakash, Anil; Price, David P; Rajaraman, Ashok; Reimer, Lisa J; Rinker, David C; Rokas, Antonis; Russell, Tanya L; Sagnon, N'Fale; Sharakhova, Maria V; Shea, Terrance; Simão, Felipe A; Simard, Frederic; Slotman, Michel A; Somboon, Pradya; Stegniy, Vladimir; Struchiner, Claudio J; Thomas, Gregg W C; Tojo, Marta; Topalis, Pantelis; Tubio, José M C; Unger, Maria F; Vontas, John; Walton, Catherine; Wilding, Craig S; Willis, Judith H; Wu, Yi-Chieh; Yan, Guiyun; Zdobnov, Evgeny M; Zhou, Xiaofan; Catteruccia, Flaminia; Christophides, George K; Collins, Frank H; Cornman, Robert S; Crisanti, Andrea; Donnelly, Martin J; Emrich, Scott J; Fontaine, Michael C; Gelbart, William; Hahn, Matthew W; Hansen, Immo A; Howell, Paul I; Kafatos, Fotis C; Kellis, Manolis; Lawson, Daniel; Louis, Christos; Luckhart, Shirley; Muskavitch, Marc A T; Ribeiro, José M; Riehle, Michael A; Sharakhov, Igor V; Tu, Zhijian; Zwiebel, Laurence J; Besansky, Nora J

2015-01-02

Variation in vectorial capacity for human malaria among Anopheles mosquito species is determined by many factors, including behavior, immunity, and life history. To investigate the genomic basis of vectorial capacity and explore new avenues for vector control, we sequenced the genomes of 16 anopheline mosquito species from diverse locations spanning ~100 million years of evolution. Comparative analyses show faster rates of gene gain and loss, elevated gene shuffling on the X chromosome, and more intron losses, relative to Drosophila. Some determinants of vectorial capacity, such as chemosensory genes, do not show elevated turnover but instead diversify through protein-sequence changes. This dynamism of anopheline genes and genomes may contribute to their flexible capacity to take advantage of new ecological niches, including adapting to humans as primary hosts. Copyright © 2015, American Association for the Advancement of Science.

The life span-prolonging effect of sirtuin-1 is mediated by autophagy.

PubMed

Morselli, Eugenia; Maiuri, Maria Chiara; Markaki, Maria; Megalou, Evgenia; Pasparaki, Angela; Palikaras, Konstantinos; Criollo, Alfredo; Galluzzi, Lorenzo; Malik, Shoaib Ahmad; Vitale, Ilio; Michaud, Mickael; Madeo, Frank; Tavernarakis, Nektarios; Kroemer, Guido

2010-01-01

The life span of various model organisms can be extended by caloric restriction as well as by autophagy-inducing pharmacological agents. Life span-prolonging effects have also been observed in yeast cells, nematodes and flies upon the overexpression of the deacetylase Sirtuin-1. Intrigued by these observations and by the established link between caloric restriction and Sirtuin-1 activation, we decided to investigate the putative implication of Sirtuin-1 in the response of human cancer cells and Caenorhabditis elegans to multiple triggers of autophagy. Our data indicate that the activation of Sirtuin-1 (by the pharmacological agent resveratrol and/or genetic means) per se ignites autophagy, and that Sirtuin-1 is required for the autophagic response to nutrient deprivation, in both human and nematode cells, but not for autophagy triggered by downstream signals such as the inhibition of mTOR or p53. Since the life spanextending effects of Sirtuin-1 activators are lost in autophagy-deficient C. elegans, our results suggest that caloric restriction and resveratrol extend longevity, at least in experimental settings, by activating autophagy.

Lateral Gene Transfer Dynamics in the Ancient Bacterial Genus Streptomyces

PubMed Central

McDonald, Bradon R.

2017-01-01

ABSTRACT Lateral gene transfer (LGT) profoundly shapes the evolution of bacterial lineages. LGT across disparate phylogenetic groups and genome content diversity between related organisms suggest a model of bacterial evolution that views LGT as rampant and promiscuous. It has even driven the argument that species concepts and tree-based phylogenetics cannot be applied to bacteria. Here, we show that acquisition and retention of genes through LGT are surprisingly rare in the ubiquitous and biomedically important bacterial genus Streptomyces. Using a molecular clock, we estimate that the Streptomyces bacteria are ~380 million years old, indicating that this bacterial genus is as ancient as land vertebrates. Calibrating LGT rate to this geologic time span, we find that on average only 10 genes per million years were acquired and subsequently maintained. Over that same time span, Streptomyces accumulated thousands of point mutations. By explicitly incorporating evolutionary timescale into our analyses, we provide a dramatically different view on the dynamics of LGT and its impact on bacterial evolution. PMID:28588130

On the long-term fitness of cells in periodically switching environments.

PubMed

Pang, Ning-Ning; Tzeng, Wen-Jer

2008-01-01

Because all the cell populations are capable of making switches between different genetic expression states in response to the environmental change, Thattai and van Oudenaarden (Genetics 167, 523-530, 2004) have raised a very interesting question: In a constantly fluctuating environment, which type of cell population (heterogeneous or homogeneous) is fitter in the long term? This problem is very important to development and evolution biology. We thus take an extensive analysis about how the cell population evolves in a periodically switching environment either with symmetrical time-span or asymmetrical time-span. A complete picture of the phase diagrams for both cases is obtained. Furthermore, we find that the systems with time-dependent cellular transitions all collapse to the same set of dynamical equations with the modified parameters. Furthermore, we also explain in detail how the fitness problem bears much resemblance to the phenomenon, stochastic resonance, in physical sciences. Our results could be helpful for the biologists to design artificial evolution experiments and unveil the mystery of development and evolution.

Physical Performance Across the Adult Life Span: Correlates With Age and Physical Activity.

PubMed

Hall, Katherine S; Cohen, Harvey J; Pieper, Carl F; Fillenbaum, Gerda G; Kraus, William E; Huffman, Kim M; Cornish, Melissa A; Shiloh, Andrew; Flynn, Christy; Sloane, Richard; Newby, L Kristin; Morey, Miriam C

2017-04-01

A number of large-scale population studies have provided valuable information about physical performance in aged individuals; however, there is little information about trajectories of function and associations with age across the adult life span. We developed a mobility-focused physical performance screener designed to be appropriate for the adult life span. The physical performance battery includes measures of mobility, strength, endurance, and balance. Physical activity (PA) was assessed with accelerometry. We examined age-related trends in physical performance and PA, and the relationship between physical performance and PA across the age range (30-90+), by decade, in 775 participants enrolled in the study 2012-2014. Physical performance was worse with increasing age decade. Although men performed better than women across all ages, the decrement by age group was similar between genders. Worsening physical performance was observed as early as the fifth decade for chair stands and balance and in the sixth decade for gait speed and aerobic endurance. The number and strength of significant associations between physical performance and PA increased with greater age: the greatest number of significant associations was seen in the 60-79 age groups, with fewer reported in the 30-59 and 80-90+ age groups. More PA was associated with better physical function. These results emphasize the importance of a life span approach to studies of function and aging. This work points to the need for a physical performance screener that spans across adulthood as a clinical tool for identifying functional decline. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Deficiency mapping of quantitative trait loci affecting longevity in Drosophila melanogaster.

PubMed Central

Pasyukova, E G; Vieira, C; Mackay, T F

2000-01-01

In a previous study, sex-specific quantitative trait loci (QTL) affecting adult longevity were mapped by linkage to polymorphic roo transposable element markers, in a population of recombinant inbred lines derived from the Oregon and 2b strains of Drosophila melanogaster. Two life span QTL were each located on chromosomes 2 and 3, within sections 33E-46C and 65D-85F on the cytological map, respectively. We used quantitative deficiency complementation mapping to further resolve the locations of life span QTL within these regions. The Oregon and 2b strains were each crossed to 47 deficiencies spanning cytological regions 32F-44E and 64C-76B, and quantitative failure of the QTL alleles to complement the deficiencies was assessed. We initially detected a minimum of five and four QTL in the chromosome 2 and 3 regions, respectively, illustrating that multiple linked factors contribute to each QTL detected by recombination mapping. The QTL locations inferred from deficiency mapping did not generally correspond to those of candidate genes affecting oxidative and thermal stress or glucose metabolism. The chromosome 2 QTL in the 35B-E region was further resolved to a minimum of three tightly linked QTL, containing six genetically defined loci, 24 genes, and predicted genes that are positional candidates corresponding to life span QTL. This region was also associated with quantitative variation in life span in a sample of 10 genotypes collected from nature. Quantitative deficiency complementation is an efficient method for fine-scale QTL mapping in Drosophila and can be further improved by controlling the background genotype of the strains to be tested. PMID:11063689

Proteotoxicity and the contrasting effects of oxaloacetate and glycerol on Caenorhabditis elegans life span: a role for methylglyoxal?

PubMed

Hipkiss, Alan R

2010-10-01

Because accumulation of altered proteins is the most common biochemical symptom of aging, it is at least possible that such proteotoxicity may cause aging and influence life span. The life span of the nematode worm Caenorhabditis elegans is strongly influenced by changes in the intracellular concentration of methylglyoxal (MG), a putative source of much age-related proteotoxicity and organelle, cellular, and molecular dysfunction. Glycerol has recently been shown to shorten, whereas oxaloacetate has been found to extend, life span in C. elegans. It is suggested here that glycerol and oxaloacetate exert opposing effects on MG formation in C. elegans. It is proposed that, if not secreted by aquaporin, glycerol is converted to glycerol phosphate and then to dihydroxyacetone phosphate (DHAP) via a reaction requiring nicotinamide adenine dinucleotide (NAD(+)). This inhibits operation of the glycerol phosphate cycle in which DHAP is converted into glycerol phosphate, which concomitantly regenerates NAD(+) from NADH, thereby ensuring glycolytic oxidation of glyceraldehyde-3-phosphate (G3P). Because DHAP and G3P spontaneously decompose into MG, and NAD(+) is required for conversion of G3P into phosphoglycerate, the glycerol-induced increased DHAP formation and decreased NAD(+) availability will increase the potential for MG generation. In contrast, oxaloacetate may decrease MG generation by stimulating the operation of the malate-oxaloacetate shuttle, in which oxaloacetate is converted to malate, which regenerates NAD(+) from NADH. By the ensuing G3P oxidation, increased NAD(+) availability will decrease the potential for MG formation. It should be noted that mitochondria are involved in the operation of the above cycle/shuttles and that increased NAD(+) availability also stimulates those sirtuin activities that increase mitogenesis and mitochondrial activity via effects on signal transduction and gene expression, which frequently accompany dietary restriction-induced life span extension.

The Social Context of Managing Diabetes across the Life Span

PubMed Central

Wiebe, Deborah J.; Helgeson, Vicki; Berg, Cynthia A.

2016-01-01

Diabetes self-management is crucial to maintaining quality of life and preventing long-term complications, and occurs daily in the context of close interpersonal relationships. This article examines how social relationships are central to meeting the complex demands of managing type 1 and type 2 diabetes across the life span. The social context of diabetes management includes multiple resources, including family (parents, spouses), peers, romantic partners, and health care providers. We discuss how these social resources change across the life span, focusing on childhood and adolescence, emerging adulthood, and adulthood and aging. We review how diabetes both affects and is affected by key social relationships at each developmental period. Despite high variability in how the social context is conceptualized and measured across studies, findings converge on the characteristics of social relationships that facilitate or undermine diabetes management across the life span. These characteristics are consistent with both Interpersonal Theory and Self-Determination Theory, two organizing frameworks that we utilize to explore social behaviors that are related to diabetes management. Involvement and support from one’s social partners, particularly family members, is consistently associated with good diabetes outcomes when characterized by warmth, collaboration and acceptance. Under-involvement and interactions characterized by conflict and criticism are consistently associated with poor diabetes outcomes. Intrusive involvement that contains elements of social control may undermine diabetes management, particularly when it impinges on self-efficacy. Implications for future research directions and for interventions that promote the effective use of the social context to improve diabetes self-management are discussed. PMID:27690482

Nup100 regulates Saccharomyces cerevisiae replicative life span by mediating the nuclear export of specific tRNAs.

PubMed

Lord, Christopher L; Ospovat, Ophir; Wente, Susan R

2017-03-01

Nuclear pore complexes (NPCs), which are composed of nucleoporins (Nups) and regulate transport between the nucleus and cytoplasm, significantly impact the replicative life span (RLS) of Saccharomyces cerevisiae We previously reported that deletion of the nonessential gene NUP100 increases RLS, although the molecular basis for this effect was unknown. In this study, we find that nuclear tRNA accumulation contributes to increased longevity in nup100 Δ cells. Fluorescence in situ hybridization (FISH) experiments demonstrate that several specific tRNAs accumulate in the nuclei of nup100 Δ mutants. Protein levels of the transcription factor Gcn4 are increased when NUP100 is deleted, and GCN4 is required for the elevated life spans of nup100 Δ mutants, similar to other previously described tRNA export and ribosomal mutants. Northern blots indicate that tRNA splicing and aminoacylation are not significantly affected in nup100 Δ cells, suggesting that Nup100 is largely required for nuclear export of mature, processed tRNAs. Distinct tRNAs accumulate in the nuclei of nup100 Δ and msn5 Δ mutants, while Los1-GFP nucleocytoplasmic shuttling is unaffected by Nup100. Thus, we conclude that Nup100 regulates tRNA export in a manner distinct from Los1 or Msn5. Together, these experiments reveal a novel Nup100 role in the tRNA life cycle that impacts the S. cerevisiae life span. © 2017 Lord et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

ASSESSING THE IMPACT OF ENVIRONMENTAL RADIATION ON TOTAL HEALTH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henshaw, P.S.

1958-09-01

Ionizing radiation is but one of various agents that affect the stamina and well-being of population groups within species through induction of mutations in both the somatoplasm and the germplasm. A preliminary effort has been made to identify and examine central and pacesetting determinants of the life process, moving thereby toward a better understanding of the role and significance of radiation. On the basis of accumulated information and deductions that follow logically, questions have been raised regarding the part natural radiation may have had in shaping the character of life processes through time, possibly influencing both the course and ratemore » of evolution and the average life-span of species, the matter of whether radiation, though injurious to cells, may not under certain circumstances have a beneficial effect in complex multicellular organisms, radiation as an agent acting to reduce the fltness reserve in organisms, and the limits of exposure so far as individual and group survival are concenned. A formulation has been developed which aids in visualizing the total health process and how this is affected positively and negatively by various factors, including radiation. By means of the formulation some impression is gained of the stability of the life process, on the one hand, and, on the other, of its extreme vulnerability if an environmental factor such as radiation is altered significantly. (auth)« less

The Impact of Recent Federal Administrative Rules on Army Dental Care. Volume 1. A Cost Analysis of Bloodborne Pathogens: A Report of Consultation

DTIC Science & Technology

1992-12-31

procedure codes 9973 and 9974), and the unit cost to the Fort Sam Houston DENTAC ($.79). Expenditures on dental handpieces were estimated using the guidance...life span after which it is due for replacement. The effects of steam sterilization on dental handpieces decreases their life span substantially... handpieces should be sterilized between patients. ADA 18 May, 1992. 12. Reddy, T.G. Director, Dental Services, US Army Health Services Command

Blood volume and red cell life span (M113), part C

NASA Technical Reports Server (NTRS)

Johnson, P. C., Jr.

1973-01-01

Prechamber, in-chamber, and postchamber blood samples taken from Skylab simulation crewmembers did not indicate significant shortening of the red cell life span during the mission. This does not suggest that the space simulation environment could not be associated with red cell enzyme changes. It does show that any changes in enzymes were not sufficiently great to significantly shorten red cell survival. There was no evidence of bone marrow erythropoetic suppression nor was there any evidence of increased red cell destruction.

Rapamycin: the cure for all that ails.

PubMed

Hasty, Paul

2010-02-01

Target of rapamycin (TOR) signaling stimulates cell growth by regulating protein synthesis in response to a variety of stimuli in a wide range of species and is inhibited by rapamycin, a naturally occurring antifungal compound produced by bacteria and discovered on Easter Island or in the local vernacular, Rapa Nui (rapamycin's namesake). Recently, rapamycin was shown to extend life span for mice, even when administered late in life, suggesting that inhibiting the mammalian TOR pathway may improve health span for people.

Relating Life-Span Research to the Development of Gifted and Talented Children. Abstracts of Selected Papers [from] The Annual Esther Katz Rosen Symposium on the Psychological Development of Gifted Children (3rd, Lawrence, Kansas, February 19-20, 1993).

ERIC Educational Resources Information Center

Kansas Univ., Lawrence.

This monograph presents abstracts of 29 papers that relate life-span research to the development of gifted and talented children. Sample topics include: attitudes about rural schools and programs for the gifted; social competence, self-esteem, and parent-child time and interaction in an advantaged subculture; helping families of gifted children…

Personality, self-rated health, and subjective age in a life-span sample: the moderating role of chronological age.

PubMed

Stephan, Yannick; Demulier, Virginie; Terracciano, Antonio

2012-12-01

The present study tested whether chronological age moderates the association between subjective age and self-rated health and personality in a community-dwelling life-span sample (N = 1,016; age range: 18-91 years). Self-rated health, extraversion, and openness to experience were associated with a younger subjective age at older ages. Conscientious individuals felt more mature early in life. Conscientiousness, neuroticism, and agreeableness were not related to subjective age at older ages. These findings suggest that with aging self-rated health and personality traits are increasingly important for subjective age. 2013 APA, all rights reserved

Hominin life history: reconstruction and evolution

PubMed Central

Robson, Shannen L; Wood, Bernard

2008-01-01

In this review we attempt to reconstruct the evolutionary history of hominin life history from extant and fossil evidence. We utilize demographic life history theory and distinguish life history variables, traits such as weaning, age at sexual maturity, and life span, from life history-related variables such as body mass, brain growth, and dental development. The latter are either linked with, or can be used to make inferences about, life history, thus providing an opportunity for estimating life history parameters in fossil taxa. We compare the life history variables of modern great apes and identify traits that are likely to be shared by the last common ancestor of Pan-Homo and those likely to be derived in hominins. All great apes exhibit slow life histories and we infer this to be true of the last common ancestor of Pan-Homo and the stem hominin. Modern human life histories are even slower, exhibiting distinctively long post-menopausal life spans and later ages at maturity, pointing to a reduction in adult mortality since the Pan-Homo split. We suggest that lower adult mortality, distinctively short interbirth intervals, and early weaning characteristic of modern humans are derived features resulting from cooperative breeding. We evaluate the fidelity of three life history-related variables, body mass, brain growth and dental development, with the life history parameters of living great apes. We found that body mass is the best predictor of great ape life history events. Brain growth trajectories and dental development and eruption are weakly related proxies and inferences from them should be made with caution. We evaluate the evidence of life history-related variables available for extinct species and find that prior to the transitional hominins there is no evidence of any hominin taxon possessing a body size, brain size or aspects of dental development much different from what we assume to be the primitive life history pattern for the Pan-Homo clade. Data for life history-related variables among the transitional hominin grade are consistent and none agrees with a modern human pattern. Aside from mean body mass, adult brain size, crown and root formation times, and the timing and sequence of dental eruption of Homo erectus are inconsistent with that of modern humans. Homo antecessor fossil material suggests a brain size similar to that of Homo erectus s. s., and crown formation times that are not yet modern, though there is some evidence of modern human-like timing of tooth formation and eruption. The body sizes, brain sizes, and dental development of Homo heidelbergensis and Homo neanderthalensis are consistent with a modern human life history but samples are too small to be certain that they have life histories within the modern human range. As more life history-related variable information for hominin species accumulates we are discovering that they can also have distinctive life histories that do not conform to any living model. At least one extinct hominin subclade, Paranthropus, has a pattern of dental life history-related variables that most likely set it apart from the life histories of both modern humans and chimpanzees. PMID:18380863

Body Size Evolution in Conodonts from the Cambrian through the Triassic

NASA Astrophysics Data System (ADS)

Schaal, E. K.; Morgan, D. J.; Payne, J.

2013-12-01

The size of an organism exercises tremendous control over its physiology, life history, and ecology, yet the factors that influence body size evolution remain poorly understood. One major limitation is the lack of appropriate datasets spanning long intervals of evolutionary time. Here, we document size trends in conodonts (tooth-like microfossils from marine chordates) because they evolved rapidly and are known to change size during intervals of environmental change. By measuring photographs from the Catalogue of Conodonts (Ziegler 1982), we compiled a database of conodont P1 element measurements for 575 species and subspecies from the Cambrian through Triassic periods. Because tooth size correlates with body size in conodont animals and their extant relatives, conodont element length can serve as a proxy for the size of the conodont animal. We find that mean and maximum size across species increased during the early Paleozoic, peaked during the Devonian-Mississippian, and then generally decreased until conodonts went extinct at the end of the Triassic. We used regression analyses to compare conodont mean size trends to potential environmental predictors, such as changing atmospheric pO2, atmospheric pCO2, and sea level. Conodont size exhibited poor correlation with these environmental factors, suggesting that conodont evolution may have been more strongly influenced by other environmental covariates or ecological variables such as predation and competition.

Evolutionary Topology of a Currency Network in Asia

NASA Astrophysics Data System (ADS)

Feng, Xiaobing; Wang, Xiaofan

Although recently there are extensive research on currency network using minimum spanning trees approach, the knowledge about the actual evolution of a currency web in Asia is still limited. In the paper, we study the structural evolution of an Asian network using daily exchange rate data. It was found that the correlation between Asian currencies and US Dollar, the previous regional key currency has become weaker and the intra-Asia interactions have increased. This becomes more salient after the exchange rate reform of China. Different from the previous studies, we further reveal that it is the trade volume, national wealth gap and countries growth cycle that has contributed to the evolutionary topology of the minimum spanning tree. These findings provide a valuable platform for theoretical modeling and further analysis.

Fourth Symposium on Chemical Evolution and the Origin and Evolution of Life

NASA Technical Reports Server (NTRS)

Wharton, Robert A., Jr. (Editor); Andersen, Dale T. (Editor); Bzik, Sara E. (Editor); Rummel, John D. (Editor)

1991-01-01

This symposium was held at the NASA Ames Research Center, Moffett Field, California, July 24-27, 1990. The NASA exobiology investigators reported their recent research findings. Scientific papers were presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

The three-dimensional evolution of a plane mixing layer. Part 2: Pairing and transition to turbulence

NASA Technical Reports Server (NTRS)

Moser, Robert D.; Rogers, Michael M.

1992-01-01

The evolution of three-dimensional temporally evolving plane mixing layers through as many as three pairings was simulated numerically. Initial conditions for all simulations consisted of a few low-wavenumber disturbances, usually derived from linear stability theory, in addition to the mean velocity. Three-dimensional perturbations were used with amplitudes ranging from infinitesimal to large enough to trigger a rapid transition to turbulence. Pairing is found both to inhibit the growth of infinitesimal three-dimensional disturbances and to trigger the transition to turbulence in highly three dimensional flows. The mechanisms responsible for the growth of three-dimensionality as well as the initial phases of the transition to turbulence are described. The transition to turbulence is accompanied by the formation of thin sheets of span wise vorticity, which undergo a secondary roll up. Transition also produces an increase in the degree of scalar mixing, in agreement with experimental observations of mixing transition. Simulations were also conducted to investigate changes in span wise length scale that may occur in response to the change in stream wise length scale during a pairing. The linear mechanism for this process was found to be very slow, requiring roughly three pairings to complete a doubling of the span wise scale. Stronger three-dimensionality can produce more rapid scale changes but is also likely to trigger transition to turbulence. No evidence was found for a change from an organized array of rib vortices at one span wise scale to a similar array at a larger span wise scale.

The Tölz Temporal Topography Study: mapping the visual field across the life span. Part II: cognitive factors shaping visual field maps.

PubMed

Poggel, Dorothe A; Treutwein, Bernhard; Calmanti, Claudia; Strasburger, Hans

2012-08-01

Part I described the topography of visual performance over the life span. Performance decline was explained only partly by deterioration of the optical apparatus. Part II therefore examines the influence of higher visual and cognitive functions. Visual field maps for 95 healthy observers of static perimetry, double-pulse resolution (DPR), reaction times, and contrast thresholds, were correlated with measures of visual attention (alertness, divided attention, spatial cueing), visual search, and the size of the attention focus. Correlations with the attentional variables were substantial, particularly for variables of temporal processing. DPR thresholds depended on the size of the attention focus. The extraction of cognitive variables from the correlations between topographical variables and participant age substantially reduced those correlations. There is a systematic top-down influence on the aging of visual functions, particularly of temporal variables, that largely explains performance decline and the change of the topography over the life span.

Effects of High Magneto-Gravitational Environment on Silkworm Embryogenesis

NASA Astrophysics Data System (ADS)

Tian, Zongcheng; Li, Muwang; Qian, Airong; Xu, Huiyun; Wang, Zhe; Di, Shengmeng; Yang, Pengfei; Hu, Lifang; Ding, Chong; Zhang, Wei; Luo, Mingzhi; Han, Jing; Gao, Xiang; Huang, Yongping; Shang, Peng

2010-04-01

The objective of this research was to observe whether silkworm embryos can survive in a high magneto-gravitational environment (HMGE) and what significant phenotype changes can be produced. The hatching rate, hatching time, life span, growth velocity and cocoon weight of silkworm were measured after silkworm embryos were exposed to HMGE (0 g, 12 T; 1 g, 16 T; and 2 g, 12 T) for a period of time. Compared with the control group, 0 g exposure resulted in a lower hatching rate and a shorter life span. Statistically insignificant morphological changes had been observed for larvae growth velocity, incidence of abnormal markings and weight of cocoons. These results suggest that the effect of HMGE on silkworm embryogenesis is not lethal. Bio-effects of silkworm embryogenesis at 0 g in a HMGE were similar with those of space flight. The hatching time, life span and hatching rates of silkworm may be potential phenotype markers related to exposure in a weightless environment.

Review of certain low-level ionizing radiation studies in mice and guinea pigs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Congdon, C.C.

1987-05-01

Starting in the early 1940s, Egon Lorenz and collaborators at the National Cancer Institute began an extended study of chronic low-level ionizing radiation effects in what was then the tolerance range for man. Observations on life span, body weight and radiation carcinogenesis, among others, were made in mice, guinea pigs and rabbits. At the then-permissible exposure level, 0.1 R** per 8-h day until natural death, experimental mice and guinea pigs had a slightly greater mean life span compared to control animals. In addition, there was marked weight gain during the growth phase in both species. Increased tumor incidence was alsomore » observed at the 0.1-R level in mice. The primary hypothesis for increased median life span has been rebound regenerative hyperplasia during the early part of the exposure; in the presence of continuing injury, there is physiological enhancement of defense mechanisms against intercurrent infection. The body weight gain has not been explained. 32 references.« less

Spermidine: a novel autophagy inducer and longevity elixir.

PubMed

Madeo, Frank; Eisenberg, Tobias; Büttner, Sabrina; Ruckenstuhl, Christoph; Kroemer, Guido

2010-01-01

Spermidine is a ubiquitous polycation that is synthesized from putrescine and serves as a precursor of spermine. Putrescine, spermidine and spermine all are polyamines that participate in multiple known and unknown biological processes. Exogenous supply of spermidine prolongs the life span of several model organisms including yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans) and flies (Drosophila melanogaster) and significantly reduces age-related oxidative protein damage in mice, indicating that this agent may act as a universal anti-aging drug. Spermidine induces autophagy in cultured yeast and mammalian cells, as well as in nematodes and flies. Genetic inactivation of genes essential for autophagy abolishes the life span-prolonging effect of spermidine in yeast, nematodes and flies. These findings complement expanding evidence that autophagy mediates cytoprotection against a variety of noxious agents and can confer longevity when induced at the whole-organism level. We hypothesize that increased autophagic turnover of cytoplasmic organelles or long-lived proteins is involved in most if not all life span-prolonging therapies.

Conditional inhibition of autophagy genes in adult Drosophila impairs immunity without compromising longevity.

PubMed

Ren, Chunli; Finkel, Steven E; Tower, John

2009-03-01

Immune function declines with age in Drosophila and humans, and autophagy is implicated in immune function. In addition, autophagy genes are required for life span extension caused by reduced insulin/IGF1-like signaling and dietary restriction in Caenorhabditiselegans. To test if the autophagy pathway might be limiting for immunity and/or life span in adult Drosophila, the Geneswitch system was used to cause conditional inactivation of the autophagy genes Atg5, Atg7 and Atg12 by RNAi. Conditional inhibition of Atg genes in adult flies reduced lysotracker staining of adult tissues, and reduced resistance to injected Escherichia coli, as evidenced by increased bacterial titers and reduced fly survival. However, survival of uninjected flies was unaffected by Atg gene inactivation. The data indicate that Atg gene activity is required for normal immune function in adult flies, and suggest that neither autophagy nor immune function are limiting for adult life span under typical laboratory conditions.

Variation in Age and Size in Fennoscandian Three-Spined Sticklebacks (Gasterosteus aculeatus)

PubMed Central

DeFaveri, Jacquelin; Merilä, Juha

2013-01-01

Average age and maximum life span of breeding adult three-spined sticklebacks (Gasterosteus aculeatus) were determined in eight Fennoscandian localities with the aid of skeletochronology. The average age varied from 1.8 to 3.6 years, and maximum life span from three to six years depending on the locality. On average, fish from marine populations were significantly older than those from freshwater populations, but variation within habitat types was large. We also found significant differences in mean body size among different habitat types and populations, but only the population differences remained significant after accounting for variation due to age effects. These results show that generation length and longevity in three-spined sticklebacks can vary significantly from one locality to another, and that population differences in mean body size cannot be explained as a simple consequence of differences in population age structure. We also describe a nanistic population from northern Finland exhibiting long life span and small body size. PMID:24260496

Variation in age and size in Fennoscandian three-spined sticklebacks (Gasterosteus aculeatus).

PubMed

DeFaveri, Jacquelin; Merilä, Juha

2013-01-01

Average age and maximum life span of breeding adult three-spined sticklebacks (Gasterosteus aculeatus) were determined in eight Fennoscandian localities with the aid of skeletochronology. The average age varied from 1.8 to 3.6 years, and maximum life span from three to six years depending on the locality. On average, fish from marine populations were significantly older than those from freshwater populations, but variation within habitat types was large. We also found significant differences in mean body size among different habitat types and populations, but only the population differences remained significant after accounting for variation due to age effects. These results show that generation length and longevity in three-spined sticklebacks can vary significantly from one locality to another, and that population differences in mean body size cannot be explained as a simple consequence of differences in population age structure. We also describe a nanistic population from northern Finland exhibiting long life span and small body size.

All about Animal Life Cycles. Animal Life for Children. [Videotape].

ERIC Educational Resources Information Center

2000

While watching the development from tadpole to frog, caterpillar to butterfly, and pup to wolf, children learn about the life cycles of animals, the different stages of development, and the average life spans of a variety of creatures. This videotape correlates to the following National Science Education Standards for Life Science: characteristics…

Holistic life-span health outcomes among elite intercollegiate student-athletes.

PubMed

Sorenson, Shawn C; Romano, Russell; Scholefield, Robin M; Martin, Brandon E; Gordon, James E; Azen, Stanley P; Schroeder, E Todd; Salem, George J

2014-01-01

Competitive sports are recognized as having unique health benefits and risks, and the effect of sports on life-span health among elite athletes has received increasing attention. However, supporting scientific data are sparse and do not represent modern athletes. To assess holistic life-span health and health-related quality-of-life (HRQL) among current and former National Collegiate Athletic Association student-athletes (SAs). Cross-sectional study. A large Division I university. Population-based sample of 496 university students and alumni (age 17-84 years), including SAs and an age-matched and sex-matched nonathlete (NA) control group. Participants completed anonymous, self-report questionnaires. We measured the Short-Form 12 (SF-12) physical and mental component HRQL scores and cumulative lifetime experience and relative risk of treatment for joint, cardiopulmonary, and psychosocial health concerns. Older alumni (age 43+ years) SAs reported greater joint health concerns than NAs (larger joint summary scores; P = .04; Cohen d = 0.69; probability of clinically important difference [pCID] = 77%; treatment odds ratio [OR] = 14.0, 95% confidence interval [CI] = 1.6, 126). Joint health for current and younger alumni SAs was similar to that for NAs. Older alumni reported greater cardiopulmonary health concerns than younger alumni (summary score P < .001; d = 1.05; pCID = 85%; OR = 5.8, 95% CI = 2.0, 16) and current students (P < .001; d = 2.25; pCID >99.5%; OR = 7.1, 95% CI = 3.3, 15), but the risk was similar for SAs and NAs. Current SAs demonstrated evidence of better psychosocial health (summary score P = .006; d = -0.52; pCID = 40%) and mental component HRQL (P = .008; d = 0.50; pCID = 48%) versus NAs but similar psychosocial treatment odds (OR = 0.87, 95% CI = 0.39, 1.9). Psychosocial health and mental component HRQL were similar between alumni SAs and NAs. No differences were observed between SAs and NAs in physical component HRQL. The SAs demonstrated significant, clinically meaningful evidence of greater joint health concerns later in life, comparable cardiopulmonary health, and differences in life-span psychosocial health and HRQL profiles compared with NAs. These data provide timely evidence regarding a compelling public issue and highlight the need for further study of life-span health among modern athletes.

Holistic Life-Span Health Outcomes Among Elite Intercollegiate Student–Athletes

PubMed Central

Sorenson, Shawn C.; Romano, Russell; Scholefield, Robin M.; Martin, Brandon E.; Gordon, James E.; Azen, Stanley P.; Schroeder, E. Todd; Salem, George J.

2014-01-01

Context: Competitive sports are recognized as having unique health benefits and risks, and the effect of sports on life-span health among elite athletes has received increasing attention. However, supporting scientific data are sparse and do not represent modern athletes. Objective: To assess holistic life-span health and health-related quality-of-life (HRQL) among current and former National Collegiate Athletic Association student–athletes (SAs). Design: Cross-sectional study. Setting: A large Division I university. Patients or Other Participants: Population-based sample of 496 university students and alumni (age 17–84 years), including SAs and an age-matched and sex-matched nonathlete (NA) control group. Main Outcome Measure(s): Participants completed anonymous, self-report questionnaires. We measured the Short-Form 12 (SF-12) physical and mental component HRQL scores and cumulative lifetime experience and relative risk of treatment for joint, cardiopulmonary, and psychosocial health concerns. Results: Older alumni (age 43+ years) SAs reported greater joint health concerns than NAs (larger joint summary scores; P = .04; Cohen d = 0.69; probability of clinically important difference [pCID] = 77%; treatment odds ratio [OR] = 14.0, 95% confidence interval [CI] = 1.6, 126). Joint health for current and younger alumni SAs was similar to that for NAs. Older alumni reported greater cardiopulmonary health concerns than younger alumni (summary score P < .001; d = 1.05; pCID = 85%; OR = 5.8, 95% CI = 2.0, 16) and current students (P < .001; d = 2.25; pCID >99.5%; OR = 7.1, 95% CI = 3.3, 15), but the risk was similar for SAs and NAs. Current SAs demonstrated evidence of better psychosocial health (summary score P = .006; d = −0.52; pCID = 40%) and mental component HRQL (P = .008; d = 0.50; pCID = 48%) versus NAs but similar psychosocial treatment odds (OR = 0.87, 95% CI = 0.39, 1.9). Psychosocial health and mental component HRQL were similar between alumni SAs and NAs. No differences were observed between SAs and NAs in physical component HRQL. Conclusions: The SAs demonstrated significant, clinically meaningful evidence of greater joint health concerns later in life, comparable cardiopulmonary health, and differences in life-span psychosocial health and HRQL profiles compared with NAs. These data provide timely evidence regarding a compelling public issue and highlight the need for further study of life-span health among modern athletes. PMID:25117874

The evolution of life cycle complexity in aphids: Ecological optimization or historical constraint?

PubMed

Hardy, Nate B; Peterson, Daniel A; von Dohlen, Carol D

2015-06-01

For decades, biologists have debated why many parasites have obligate multihost life cycles. Here, we use comparative phylogenetic analyses of aphids to evaluate the roles of ecological optimization and historical constraint in the evolution of life cycle complexity. If life cycle complexity is adaptive, it should be evolutionarily labile, that is, change in response to selection. We provide evidence that this is true in some aphids (aphidines), but not others (nonaphidines)-groups that differ in the intensity of their relationships with primary hosts. Next, we test specific mechanisms by which life cycle complexity could be adaptive or a constraint. We find that among aphidines there is a strong association between complex life cycles and polyphagy but only a weak correlation between life cycle complexity and reproductive mode. In contrast, among nonaphidines the relationship between life cycle complexity and host breadth is weak but the association between complex life cycles and sexual reproduction is strong. Thus, although the adaptiveness of life cycle complexity appears to be lineage specific, across aphids, life cycle evolution appears to be tightly linked with the evolution of other important natural history traits. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

"Pull and push back" concepts of longevity and life span extension.

PubMed

Muradian, Khachik

2013-12-01

The negative relation between metabolism and life span is a fundamental gerontological discovery well documented in a variety of ontogenetic and phylogenetic models. But how the long-lived species and populations sustain lower metabolic rate and, in more general terms, what is the efficient way to decline the metabolism? The suggested 'pull and push back' hypothesis assumes that decreased Po2 (hypoxia) and/or increased [Formula: see text] (hypercapnia) may create preconditions for the declined metabolic and aging rates. However, wider implementation of such ideas is compromised because of little advances in modification of the metabolic rate. Artificial atmosphere with controlled [Formula: see text] and [Formula: see text] could be a promising approach because of the minimal external invasions and involvement of the backward and forward loops ensuring physiological self-regulation of the metabolic perturbations. General considerations and existing data indicate that manipulations of [Formula: see text] may be more efficient in life span extension than [Formula: see text]. Thus, maximum life span of mammals positively correlates with the blood [Formula: see text] and HCO3 (-) but not with [Formula: see text]. Yet, proportional decease of the body [Formula: see text] and increase of [Formula: see text] seems the most optimal regime ensuring lower losses of the energy equivalents. Furthermore, especially rewarding results could be expected when such changes are modeled without major external invasions using the animals' inner capacity to consume O2 and generate CO2, as it is typical for the extreme longevity.

Down regulation of miR-124 in both Werner syndrome DNA helicase mutant mice and mutant Caenorhabditis elegans wrn-1 reveals the importance of this microRNA in accelerated aging

PubMed Central

Dallaire, Alexandra; Garand, Chantal; Paquet, Eric R.; Mitchell, Sarah J.; de Cabo, Rafael; Simard, Martin J.

2012-01-01

Small non-coding microRNAs are believed to be involved in the mechanism of aging but nothing is known on the impact of microRNAs in the progeroid disorder Werner syndrome (WS). WS is a premature aging disorder caused by mutations in a RecQ-like DNA helicase. Mice lacking the helicase domain of the WRN ortholog exhibit many phenotypic features of WS, including a pro-oxidant status and a shorter mean life span. Caenorhabditis elegans (C. elegans) with a nonfunctional wrn-1 DNA helicase also exhibit a shorter life span. Thus, both models are relevant to study the expression of microRNAs involved in WS. In this study, we show that miR-124 expression is lost in the liver of Wrn helicase mutant mice. Interestingly, the expression of this conserved miR-124 in whole wrn-1 mutant worms is also significantly reduced. The loss of mir-124 in C. elegans increases reactive oxygen species formation and accumulation of the aging marker lipofuscin, reduces whole body ATP levels and results in a reduction in life span. Finally, supplementation of vitamin C normalizes the median life span of wrn-1 and mir-124 mutant worms. These results suggest that biological pathways involving WRN and miR-124 are conserved in the aging process across different species. PMID:23075628

Elevated CO2 and O3 effects on fine-root survivorship in ponderosa pine mesocosms.

PubMed

Phillips, Donald L; Johnson, Mark G; Tingey, David T; Storm, Marjorie J

2009-07-01

Atmospheric carbon dioxide (CO(2)) and ozone (O(3)) concentrations are rising, which may have opposing effects on tree C balance and allocation to fine roots. More information is needed on interactive CO(2) and O(3) effects on roots, particularly fine-root life span, a critical demographic parameter and determinant of soil C and N pools and cycling rates. We conducted a study in which ponderosa pine (Pinus ponderosa) seedlings were exposed to two levels of CO(2) and O(3) in sun-lit controlled-environment mesocosms for 3 years. Minirhizotrons were used to monitor individual fine roots in three soil horizons every 28 days. Proportional hazards regression was used to analyze effects of CO(2), O(3), diameter, depth, and season of root initiation on fine-root survivorship. More fine roots were produced in the elevated CO(2) treatment than in ambient CO(2). Elevated CO(2), increasing root diameter, and increasing root depth all significantly increased fine-root survivorship and median life span. Life span was slightly, but not significantly, lower in elevated O(3), and increased O(3) did not reduce the effect of elevated CO(2). Median life spans varied from 140 to 448 days depending on the season of root initiation. These results indicate the potential for elevated CO(2) to increase the number of fine roots and their residence time in the soil, which is also affected by root diameter, root depth, and phenology.

Loss of the clock protein PER2 shortens the erythrocyte life span in mice.

PubMed

Sun, Qi; Zhao, Yue; Yang, Yunxia; Yang, Xiao; Li, Minghui; Xu, Xi; Wen, Dan; Wang, Junsong; Zhang, Jianfa

2017-07-28

Cell proliferation and release from the bone marrow have been demonstrated to be controlled by circadian rhythms in both humans and mice. However, it is unclear whether local circadian clocks in the bone marrow influence physiological functions and life span of erythrocytes. Here, we report that loss of the clock gene Per2 significantly decreased erythrocyte life span. Mice deficient in Per2 were more susceptible to acute stresses in the erythrocytes, becoming severely anemic upon phenylhydrazine, osmotic, and H 2 O 2 challenges. 1 H NMR-based metabolomics analysis revealed that the Per2 depletion causes significant changes in metabolic profiles of erythrocytes, including increased lactate and decreased ATP levels compared with wild-type mice. The lower ATP levels were associated with hyperfunction of Na + /K + -ATPase activity in Per2 -null erythrocytes, and inhibition of Na + /K + -ATPase activity by ouabain efficiently rescued ATP levels. Per2 -null mice displayed increased levels of Na + /K + -ATPase α1 (ATP1A1) in the erythrocyte membrane, and transfection of Per2 cDNA into the erythroleukemic cell line TF-1 inhibited Atp1a1 expression. Furthermore, we observed that PER2 regulates Atp1a1 transcription through interacting with trans-acting transcription factor 1 (SP1). Our findings reveal that Per2 function in the bone marrow is required for the regulation of life span in circulating erythrocytes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Loss of Ubp3 increases silencing, decreases unequal recombination in rDNA, and shortens the replicative life span in Saccharomyces cerevisiae.

PubMed

Oling, David; Masoom, Rehan; Kvint, Kristian

2014-06-15

Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3∆ mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3∆ mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3∆ sir2∆ mutants age prematurely at the same rate as sir2∆ mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3∆ mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes. © 2014 Öling et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Successful immortalization of mesenchymal progenitor cells derived from human placenta and the differentiation abilities of immortalized cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Xiaohong; Soda, Yasushi; Takahashi, Kenji

2006-12-29

We reported previously that mesenchymal progenitor cells derived from chorionic villi of the human placenta could differentiate into osteoblasts, adipocytes, and chondrocytes under proper induction conditions and that these cells should be useful for allogeneic regenerative medicine, including cartilage tissue engineering. However, similar to human mesenchymal stem cells (hMSCs), though these placental cells can be isolated easily, they are difficult to study in detail because of their limited life span in vitro. To overcome this problem, we attempted to prolong the life span of human placenta-derived mesenchymal cells (hPDMCs) by modifying hTERT and Bmi-1, and investigated whether these modified hPDMCsmore » retained their differentiation capability and multipotency. Our results indicated that the combination of hTERT and Bmi-1 was highly efficient in prolonging the life span of hPDMCs with differentiation capability to osteogenic, adipogenic, and chondrogenic cells in vitro. Clonal cell lines with directional differentiation ability were established from the immortalized parental hPDMC/hTERT + Bmi-1. Interestingly, hPDMC/Bmi-1 showed extended proliferation after long-term growth arrest and telomerase was activated in the immortal hPDMC/Bmi-1 cells. However, the differentiation potential was lost in these cells. This study reports a method to extend the life span of hPDMCs with hTERT and Bmi-1 that should become a useful tool for the study of mesenchymal stem cells.« less

The challenges in moving from ageing to successful longevity.

PubMed

Kolovou, Genovefa; Barzilai, Nir; Caruso, Calogero; Sikora, Ewa; Capri, Miriam; Tzanetakou, Irene P; Bilianou, Helen; Avery, Peter; Katsiki, Niki; Panotopoulos, George; Franceschi, Claudio; Benetos, Athanase; Mikhailidis, Dimitri P

2014-01-01

During the last decades survival has significantly improved and centenarians are becoming a fast-growing group of the population. Human life span is mainly dependent on environmental and genetic factors. Favourable modifications of lifestyle factors (e.g. physical activity, diet and not smoking) and healthcare (e.g. effective vascular disease prevention) have also increased human life span. Genetic factors contribute to the variation of human life span by around 25%, which is believed to be more profound after 85 years of age. It is likely that multiple factors influence life span and we need answers to questions such as: 1) What does it take to reach 100?, 2) Do centenarians have better health during their lifespan compared with contemporaries who died at a younger age?, 3) Do centenarians have protective modifications of body composition, fat distribution and energy expenditure, maintain high physical and cognitive function, and sustained engagement in social and productive activities?, 4) Do centenarians have genes which contribute to longevity?, 5) Do centenarians benefit from epigenetic phenomena?, 6) Is it possible to influence the transgenerational epigenetic inheritance (epigenetic memory) which leads to longevity?, 7) Is the influence of nutrigenomics important for longevity?, 8) Do centenarians benefit more from drug treatment, particularly in primary prevention?, and, 9) Are there any potential goals for drug research? Many definitions of successful ageing have been proposed, but at present there is no consensus definition. Such definitions may need to differentiate between "Longevity Syndrome" and "Exceptional Longevity".

A comparative physical map reveals the pattern of chromosomal evolution between the turkey (Meleagris gallopavo) and chicken (Gallus gallus) genomes

PubMed Central

2011-01-01

Background A robust bacterial artificial chromosome (BAC)-based physical map is essential for many aspects of genomics research, including an understanding of chromosome evolution, high-resolution genome mapping, marker-assisted breeding, positional cloning of genes, and quantitative trait analysis. To facilitate turkey genetics research and better understand avian genome evolution, a BAC-based integrated physical, genetic, and comparative map was developed for this important agricultural species. Results The turkey genome physical map was constructed based on 74,013 BAC fingerprints (11.9 × coverage) from two independent libraries, and it was integrated with the turkey genetic map and chicken genome sequence using over 41,400 BAC assignments identified by 3,499 overgo hybridization probes along with > 43,000 BAC end sequences. The physical-comparative map consists of 74 BAC contigs, with an average contig size of 13.6 Mb. All but four of the turkey chromosomes were spanned on this map by three or fewer contigs, with 14 chromosomes spanned by a single contig and nine chromosomes spanned by two contigs. This map predicts 20 to 27 major rearrangements distinguishing turkey and chicken chromosomes, despite up to 40 million years of separate evolution between the two species. These data elucidate the chromosomal evolutionary pattern within the Phasianidae that led to the modern turkey and chicken karyotypes. The predominant rearrangement mode involves intra-chromosomal inversions, and there is a clear bias for these to result in centromere locations at or near telomeres in turkey chromosomes, in comparison to interstitial centromeres in the orthologous chicken chromosomes. Conclusion The BAC-based turkey-chicken comparative map provides novel insights into the evolution of avian genomes, a framework for assembly of turkey whole genome shotgun sequencing data, and tools for enhanced genetic improvement of these important agricultural and model species. PMID:21906286

Development of the Life Story in Early Adolescence

ERIC Educational Resources Information Center

Steiner, Kristina L.; Pillemer, David B.

2018-01-01

Life span developmental psychology proposes that the ability to create a coherent life narrative does not develop until early adolescence. Using a novel methodology, 10-, 12-, and 14-year-old participants were asked to tell their life stories aloud to a researcher. Later, participants separated their transcribed narratives into self-identified…

Perceptions of Life Changes: An Alternate Measure of Aging through Time.

ERIC Educational Resources Information Center

Suggs, Patricia K.; Kivett, Vira R.

Retrospective strategies measuring perceived life changes over time can further the advancement of life span developmental research. Researchers have neglected the individual's perception of his/her life changes over time. This study attempts to determine discriminators of change over time as operationalized by perceptions of change. Subjects…

Are we alone? Lessons from the evolution of life on earth.

PubMed

Via, S

2001-12-01

The understanding of life on Earth that we have obtained from the science of evolutionary biology offers clues to the qustion of what life might be like if found elsewhere. After presenting the basics of the evolutionary process, I discuss the factors that determine the outcome of evolution, the role of key innovations and extinction in evolution, and whether the evolution of human life is inevitable.

A field investigation on the effects of background erosion on the free span development of a submarine pipeline

NASA Astrophysics Data System (ADS)

Wen, Shipeng; Xu, Jishang; Hu, Guanghai; Dong, Ping; Shen, Hong

2015-08-01

The safety of submarine pipelines is largely influenced by free spans and corrosions. Previous studies on free spans caused by seabed scours are mainly based on the stable environment, where the background seabed scour is in equilibrium and the soil is homogeneous. To study the effects of background erosion on the free span development of subsea pipelines, a submarine pipeline located at the abandoned Yellow River subaqueous delta lobe was investigated with an integrated surveying system which included a Multibeam bathymetric system, a dual-frequency side-scan sonar, a high resolution sub-bottom profiler, and a Magnetic Flux Leakage (MFL) sensor. We found that seabed homogeneity has a great influence on the free span development of the pipeline. More specifically, for homogeneous background scours, the morphology of scour hole below the pipeline is quite similar to that without the background scour, whereas for inhomogeneous background scour, the nature of spanning is mainly dependent on the evolution of seabed morphology near the pipeline. Magnetic Flux Leakage (MFL) detection results also reveal the possible connection between long free spans and accelerated corrosion of the pipeline.

Chemical Evolution and the Evolutionary Definition of Life.

PubMed

Higgs, Paul G

2017-06-01

Darwinian evolution requires a mechanism for generation of diversity in a population, and selective differences between individuals that influence reproduction. In biology, diversity is generated by mutations and selective differences arise because of the encoded functions of the sequences (e.g., ribozymes or proteins). Here, I draw attention to a process that I will call chemical evolution, in which the diversity is generated by random chemical synthesis instead of (or in addition to) mutation, and selection acts on physicochemical properties, such as hydrolysis, photolysis, solubility, or surface binding. Chemical evolution applies to short oligonucleotides that can be generated by random polymerization, as well as by template-directed replication, and which may be too short to encode a specific function. Chemical evolution is an important stage on the pathway to life, between the stage of "just chemistry" and the stage of full biological evolution. A mathematical model is presented here that illustrates the differences between these three stages. Chemical evolution leads to much larger differences in molecular concentrations than can be achieved by selection without replication. However, chemical evolution is not open-ended, unlike biological evolution. The ability to undergo Darwinian evolution is often considered to be a defining feature of life. Here, I argue that chemical evolution, although Darwinian, does not quite constitute life, and that a good place to put the conceptual boundary between non-life and life is between chemical and biological evolution.

The evolution of complex life.

PubMed

Billingham, J

1989-01-01

In considering the probabilities that intelligent life might exist elsewhere in the Universe, it is important to ask questions about the factors governing the emergence of complex living organisms in the context of evolutionary biology, planetary environments and events in space. Two important problems arise. First, what can be learned about the general laws governing the evolution of complex life anywhere in space by studying its history on the Earth? Second, how is the evolution of complex life affected by events in space? To address these problems, a series of Science Workshops on the Evolution of Complex Life was held at the Ames Research Center. Included in this paper are highlights of those workshops, with particular emphasis on the first question, namely the evolution of complex extraterrestrial life.

From Children to Adults: Motor Performance across the Life-Span

PubMed Central

Leversen, Jonas S. R.; Haga, Monika; Sigmundsson, Hermundur

2012-01-01

The life-span approach to development provides a theoretical framework to examine the general principles of life-long development. This study aims to investigate motor performance across the life span. It also aims to investigate if the correlations between motor tasks increase with aging. A cross-sectional design was used to describe the effects of aging on motor performance across age groups representing individuals from childhood to young adult to old age. Five different motor tasks were used to study changes in motor performance within 338 participants (7–79 yrs). Results showed that motor performance increases from childhood (7–9) to young adulthood (19–25) and decreases from young adulthood (19–25) to old age (66–80). These results are mirroring results from cognitive research. Correlation increased with increasing age between two fine motor tasks and two gross motor tasks. We suggest that the findings might be explained, in part, by the structural changes that have been reported to occur in the developing and aging brain and that the theory of Neural Darwinism can be used as a framework to explain why these changes occur. PMID:22719958

Inbreeding Depression and Male Survivorship in Drosophila: Implications for Senescence Theory

PubMed Central

Swindell, William R.; Bouzat, Juan L.

2006-01-01

The extent to which inbreeding depression affects longevity and patterns of survivorship is an important issue from several research perspectives, including evolutionary biology, conservation biology, and the genetic analysis of quantitative traits. However, few previous inbreeding depression studies have considered longevity as a focal life-history trait. We maintained laboratory populations of Drosophila melanogaster at census population sizes of 2 and 10 male-female pairs for up to 66 generations and performed repeated assays of male survivorship throughout this time period. On average, significant levels of inbreeding depression were observed for median life span and age-specific mortality. For age-specific mortality, the severity of inbreeding depression increased over the life span. We found that a baseline inbreeding load of 0.307 lethal equivalents per gamete affected age-specific mortality, and that this value increased at a rate of 0.046 per day of the life span. With respect to some survivorship parameters, the differentiation of lineages was nonlinear with respect to the inbreeding coefficient, which suggested that nonadditive genetic variation contributed to variation among lineages. These findings provide insights into the genetic basis of longevity as a quantitative trait and have implications regarding the mutation-accumulation evolutionary explanation of senescence. PMID:16204222

A Low Protein Diet Increases the Hypoxic Tolerance in Drosophila

PubMed Central

Vigne, Paul; Frelin, Christian

2006-01-01

Dietary restriction is well known to increase the life span of a variety of organisms from yeast to mammals, but the relationships between nutrition and the hypoxic tolerance have not yet been considered. Hypoxia is a major cause of cell death in myocardial infarction and stroke. Here we forced hypoxia-related death by exposing one-day-old male Drosophila to chronic hypoxia (5% O2) and analysed their survival. Chronic hypoxia reduced the average life span from 33.6 days to 6.3 days when flies were fed on a rich diet. A demographic analysis indicated that chronic hypoxia increased the slope of the mortality trajectory and not the short-term risk of death. Dietary restriction produced by food dilution, by yeast restriction, or by amino acid restriction partially reversed the deleterious action of hypoxia. It increased the life span of hypoxic flies up to seven days, which represented about 25% of the life time of an hypoxic fly. Maximum survival of hypoxic flies required only dietary sucrose, and it was insensitive to drugs such as rapamycin and resveratrol, which increase longevity of normoxic animals. The results thus uncover a new link between protein nutrition, nutrient signalling, and resistance to hypoxic stresses. PMID:17183686

Development of "material-specific" hemispheric specialization from beginning to end.

PubMed

Gingras, Benjamin; Braun, Claude M J

2018-07-01

Disparity of verbal and performance intelligence (VIQ, PIQ) on the Wechsler scales of intelligence is a conceptually cluttered and empirically weak measure of hemispheric specialization (HS). However, in the context of life span research, it is the only measure that can be exploited meta-analytically with the lesion method from prenatal life to late senescence. We assembled 1917 cases with a unilateral cortical focal brain lesion occurring at all ages and a post-lesion VIQ and PIQ. Lesion locus, volume and side were documented for each case, as well as age at lesion onset, age at first symptoms and age at the IQ test, presence/absence of epilepsy, lesion aetiology, gender, date of publication or of transfer of medical file. With and without covariate adjustment, HS was significant across the life span though its pattern changed. HS increased linearly and highly significantly until late senescence. Only in early adulthood did VIQ appear to vacate the right temporal lobe and occupy the left and PIQ vacate the left parietal lobe and occupy the right until late senescence. Biomaturational factors are more important in the ontogeny of material-specific HS over the whole life span than previously established.

Rapamycin Increases Mortality in db/db Mice, a Mouse Model of Type 2 Diabetes.

PubMed

Sataranatarajan, Kavithalakshmi; Ikeno, Yuji; Bokov, Alex; Feliers, Denis; Yalamanchili, Himabindu; Lee, Hak Joo; Mariappan, Meenalakshmi M; Tabatabai-Mir, Hooman; Diaz, Vivian; Prasad, Sanjay; Javors, Martin A; Ghosh Choudhury, Goutam; Hubbard, Gene B; Barnes, Jeffrey L; Richardson, Arlan; Kasinath, Balakuntalam S

2016-07-01

We examined the effect of rapamycin on the life span of a mouse model of type 2 diabetes, db/db mice. At 4 months of age, male and female C57BLKSJ-lepr (db/db) mice (db/db) were placed on either a control diet, lacking rapamycin or a diet containing rapamycin and maintained on these diets over their life span. Rapamycin was found to reduce the life span of the db/db mice. The median survival of male db/db mice fed the control and rapamycin diets was 349 and 302 days, respectively, and the median survival of female db/db mice fed the control and rapamycin diets was 487 and 411 days, respectively. Adjusting for gender differences, rapamycin increased the mortality risk 1.7-fold in both male and female db/db mice. End-of-life pathological data showed that suppurative inflammation was the main cause of death in the db/db mice, which is enhanced slightly by rapamycin treatment. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Getting older isn’t all that bad: Better decisions and coping when facing ’sunk costs’

PubMed Central

de Bruin, Wändi Bruine; Strough, JoNell; Parker, Andrew M.

2014-01-01

Because people of all ages face decisions that affect their quality of life, decision-making competence is important across the life span. According to theories of rational decision making, one crucial decision skill involves the ability to discontinue failing commitments despite irrecoverable investments also referred to as ‘sunk costs.’ We find that older adults are better than younger adults at making decisions to discontinue such failing commitments especially when irrecoverable losses are large, as well as at coping with the associated irrecoverable losses. Our results are relevant to interventions that aim to promote better decision-making competence across the life span. PMID:25244483

Getting older isn't all that bad: better decisions and coping when facing "sunk costs".

PubMed

Bruine de Bruin, Wändi; Strough, JoNell; Parker, Andrew M

2014-09-01

Because people of all ages face decisions that affect their quality of life, decision-making competence is important across the life span. According to theories of rational decision making, one crucial decision skill involves the ability to discontinue failing commitments despite irrecoverable investments also referred to as "sunk costs." We find that older adults are better than younger adults at making decisions to discontinue such failing commitments especially when irrecoverable losses are large, as well as at coping with the associated irrecoverable losses. Our results are relevant to interventions that aim to promote better decision-making competence across the life span. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Social and demographic correlates of loneliness in late life.

PubMed

Revenson, T A; Johnson, J L

1984-02-01

Although loneliness is often viewed as a serious problem of old age, few studies have addressed either its measurement or prevalence among older populations. The present study analyzed survey data from newspaper questionnaires circulated in three North American cities (N = 2,026) in order to examine the prevalence of loneliness across the life-span and some of its correlates in late life. Loneliness decreased across the adult life-span, with respondents age 65 and older the least lonely; elders were also more satisfied with their social relationships. Neither gender nor living alone was related to loneliness for older people. The data also partially confirm the desolation hypothesis, suggesting that desolation, or the loss of an intimate attachment, rather than isolation per se is a major correlate of loneliness in late life. Further, recency of loss was strongly related to increased loneliness. Directions for future research and intervention are discussed.

Expert Panel Recommendations on Lower Urinary Tract Health of Women Across Their Life Span

PubMed Central

Losada, Liliana; Amundsen, Cindy L.; Ashton-Miller, James; Chai, Toby; Close, Clare; Damaser, Margot; DiSanto, Michael; Dmochowski, Roger; Fraser, Matthew O.; Kielb, Stephanie J.; Kuchel, George; Mueller, Elizabeth R.; Parker-Autry, Candace; Wolfe, Alan J.

2016-01-01

Abstract Urologic and kidney problems are common in women across their life span and affect their daily life, including physical activity, sexual relations, social life, and future health. Urological health in women is still understudied and the underlying mechanisms of female urological dysfunctions are not fully understood. The Society for Women's Health Research (SWHR®) recognized the need to have a roundtable discussion where researchers and clinicians would define the current state of knowledge, gaps, and recommendations for future research directions to transform women's urological health. This report summarizes the discussions, which focused on epidemiology, clinical presentation, basic science, prevention strategies, and efficacy of current therapies. Experts around the table agreed on a set of research, education, and policy recommendations that have the potential to dramatically increase awareness and improve women's urological health at all stages of life. PMID:27285829

Evolution of the head-trunk interface in tetrapod vertebrates

PubMed Central

Sefton, Elizabeth M; Bhullar, Bhart-Anjan S; Mohaddes, Zahra; Hanken, James

2016-01-01

Vertebrate neck musculature spans the transition zone between head and trunk. The extent to which the cucullaris muscle is a cranial muscle allied with the gill levators of anamniotes or is instead a trunk muscle is an ongoing debate. Novel computed tomography datasets reveal broad conservation of the cucullaris in gnathostomes, including coelacanth and caecilian, two sarcopterygians previously thought to lack it. In chicken, lateral plate mesoderm (LPM) adjacent to occipital somites is a recently identified embryonic source of cervical musculature. We fate-map this mesoderm in the axolotl (Ambystoma mexicanum), which retains external gills, and demonstrate its contribution to posterior gill-levator muscles and the cucullaris. Accordingly, LPM adjacent to the occipital somites should be regarded as posterior cranial mesoderm. The axial position of the head-trunk border in axolotl is congruent between LPM and somitic mesoderm, unlike in chicken and possibly other amniotes. DOI: http://dx.doi.org/10.7554/eLife.09972.001 PMID:27090084

RF-amide neuropeptides and their receptors in Mammals: Pharmacological properties, drug development and main physiological functions.

PubMed

Quillet, Raphaëlle; Ayachi, Safia; Bihel, Frédéric; Elhabazi, Khadija; Ilien, Brigitte; Simonin, Frédéric

2016-04-01

RF-amide neuropeptides, with their typical Arg-Phe-NH2 signature at their carboxyl C-termini, belong to a lineage of peptides that spans almost the entire life tree. Throughout evolution, RF-amide peptides and their receptors preserved fundamental roles in reproduction and feeding, both in Vertebrates and Invertebrates. The scope of this review is to summarize the current knowledge on the RF-amide systems in Mammals from historical aspects to therapeutic opportunities. Taking advantage of the most recent findings in the field, special focus will be given on molecular and pharmacological properties of RF-amide peptides and their receptors as well as on their implication in the control of different physiological functions including feeding, reproduction and pain. Recent progress on the development of drugs that target RF-amide receptors will also be addressed. Copyright © 2016 Elsevier Inc. All rights reserved.

Semicentennial tribute to the ingenious neurobiologist Christfried Jakob (1866-1956). 1. Works from Germany and the first Argentina period, 1891-1913.

PubMed

Triarhou, Lazaros C; del Cerro, Manuel

2006-01-01

This study, and the companion paper that follows, pays homage to the life and work of Christfried (also Christian or Christofredo) Jakob, a German-born neuropathologist who adopted Argentina as his country of vocation. Rated by von Economo and Koskinas among the three most important pre-1925 cortical neuro-anatomists, alongside Ramón y Cajal, Jakob is little known in the English literature. He has left an impressive record of publications, 30 richly illustrated monographs and 200 articles that span over a vast array of neurological themes, including cortical development and evolution, and the visceral brain. The present paper reviews works from his German years and the first visit to Argentina in 1899-1910. The companion paper covers his works (all in Spanish) during his 'second Argentina period', after 1913. Copyright (c) 2006 S. Karger AG, Basel.

Spatial constraints govern competition of mutant clones in human epidermis.

PubMed

Lynch, M D; Lynch, C N S; Craythorne, E; Liakath-Ali, K; Mallipeddi, R; Barker, J N; Watt, F M

2017-10-24

Deep sequencing can detect somatic DNA mutations in tissues permitting inference of clonal relationships. This has been applied to human epidermis, where sun exposure leads to the accumulation of mutations and an increased risk of skin cancer. However, previous studies have yielded conflicting conclusions about the relative importance of positive selection and neutral drift in clonal evolution. Here, we sequenced larger areas of skin than previously, focusing on cancer-prone skin spanning five decades of life. The mutant clones identified were too large to be accounted for solely by neutral drift. Rather, using mathematical modelling and computational lattice-based simulations, we show that observed clone size distributions can be explained by a combination of neutral drift and stochastic nucleation of mutations at the boundary of expanding mutant clones that have a competitive advantage. These findings demonstrate that spatial context and cell competition cooperate to determine the fate of a mutant stem cell.

Multiple Geographical Origins of Environmental Sex Determination enhanced the diversification of Darwin's Favourite Orchids.

PubMed

Pérez-Escobar, Oscar Alejandro; Chomicki, Guillaume; Condamine, Fabien L; de Vos, Jurriaan M; Martins, Aline C; Smidt, Eric C; Klitgård, Bente; Gerlach, Günter; Heinrichs, Jochen

2017-10-10

Environmental sex determination (ESD) - a change in sexual function during an individual life span driven by environmental cues - is an exceedingly rare sexual system among angiosperms. Because ESD can directly affect reproduction success, it could influence diversification rate as compared with lineages that have alternative reproductive systems. Here we test this hypothesis using a solid phylogenetic framework of Neotropical Catasetinae, the angiosperm lineage richest in taxa with ESD. We assess whether gains of ESD are associated with higher diversification rates compared to lineages with alternative systems while considering additional traits known to positively affect diversification rates in orchids. We found that ESD has evolved asynchronously three times during the last ~5 Myr. Lineages with ESD have consistently higher diversification rates than related lineages with other sexual systems. Habitat fragmentation due to mega-wetlands extinction, and climate instability are suggested as the driving forces for ESD evolution.

A reevaluation of the proposed spin-down of the white dwarf pulsar in AR Scorpii.

NASA Astrophysics Data System (ADS)

Potter, Stephen B.; Buckley, David A. H.

2018-05-01

We present high-speed optical photometric observations, spanning ˜2 years, of the recently-discovered white dwarf pulsar AR Scorpii. The amplitudes of the orbital, spin and beat modulations appear to be remarkably stable and repeatable over the time span of our observations. It has been suggested that the polarized and non-polarized emission from AR Scorpii is powered by the spin-down of the white dwarf. However, we find that our new data is inconsistent with the published spin-down ephemeris. Whilst our data is consistent with a constant spin period further observations over an extended time-base are required in order to ascertain the true spin-evolution of the white dwarf. This may have implications for the various models put forward to explain the energetics and evolution of AR Scorpii.

The Drive to Life on Wet and Icy Worlds

PubMed Central

Barge, Laura M.; Bhartia, Rohit; Bocanegra, Dylan; Bracher, Paul J.; Branscomb, Elbert; Kidd, Richard; McGlynn, Shawn; Meier, David H.; Nitschke, Wolfgang; Shibuya, Takazo; Vance, Steve; White, Lauren; Kanik, Isik

2014-01-01

Abstract This paper presents a reformulation of the submarine alkaline hydrothermal theory for the emergence of life in response to recent experimental findings. The theory views life, like other self-organizing systems in the Universe, as an inevitable outcome of particular disequilibria. In this case, the disequilibria were two: (1) in redox potential, between hydrogen plus methane with the circuit-completing electron acceptors such as nitrite, nitrate, ferric iron, and carbon dioxide, and (2) in pH gradient between an acidulous external ocean and an alkaline hydrothermal fluid. Both CO2 and CH4 were equally the ultimate sources of organic carbon, and the metal sulfides and oxyhydroxides acted as protoenzymatic catalysts. The realization, now 50 years old, that membrane-spanning gradients, rather than organic intermediates, play a vital role in life's operations calls into question the idea of “prebiotic chemistry.” It informs our own suggestion that experimentation should look to the kind of nanoengines that must have been the precursors to molecular motors—such as pyrophosphate synthetase and the like driven by these gradients—that make life work. It is these putative free energy or disequilibria converters, presumably constructed from minerals comprising the earliest inorganic membranes, that, as obstacles to vectorial ionic flows, present themselves as the candidates for future experiments. Key Words: Methanotrophy—Origin of life. Astrobiology 14, 308–343. The fixation of inorganic carbon into organic material (autotrophy) is a prerequisite for life and sets the starting point of biological evolution. (Fuchs, 2011) Further significant progress with the tightly membrane-bound H+-PPase family should lead to an increased insight into basic requirements for the biological transport of protons through membranes and its coupling to phosphorylation. (Baltscheffsky et al., 1999) PMID:24697642

The drive to life on wet and icy worlds.

PubMed

Russell, Michael J; Barge, Laura M; Bhartia, Rohit; Bocanegra, Dylan; Bracher, Paul J; Branscomb, Elbert; Kidd, Richard; McGlynn, Shawn; Meier, David H; Nitschke, Wolfgang; Shibuya, Takazo; Vance, Steve; White, Lauren; Kanik, Isik

2014-04-01

This paper presents a reformulation of the submarine alkaline hydrothermal theory for the emergence of life in response to recent experimental findings. The theory views life, like other self-organizing systems in the Universe, as an inevitable outcome of particular disequilibria. In this case, the disequilibria were two: (1) in redox potential, between hydrogen plus methane with the circuit-completing electron acceptors such as nitrite, nitrate, ferric iron, and carbon dioxide, and (2) in pH gradient between an acidulous external ocean and an alkaline hydrothermal fluid. Both CO2 and CH4 were equally the ultimate sources of organic carbon, and the metal sulfides and oxyhydroxides acted as protoenzymatic catalysts. The realization, now 50 years old, that membrane-spanning gradients, rather than organic intermediates, play a vital role in life's operations calls into question the idea of "prebiotic chemistry." It informs our own suggestion that experimentation should look to the kind of nanoengines that must have been the precursors to molecular motors-such as pyrophosphate synthetase and the like driven by these gradients-that make life work. It is these putative free energy or disequilibria converters, presumably constructed from minerals comprising the earliest inorganic membranes, that, as obstacles to vectorial ionic flows, present themselves as the candidates for future experiments. Key Words: Methanotrophy-Origin of life. Astrobiology 14, 308-343. The fixation of inorganic carbon into organic material (autotrophy) is a prerequisite for life and sets the starting point of biological evolution. (Fuchs, 2011 ) Further significant progress with the tightly membrane-bound H(+)-PPase family should lead to an increased insight into basic requirements for the biological transport of protons through membranes and its coupling to phosphorylation. (Baltscheffsky et al., 1999 ).

Facilitating Career Development through Super's Life Career Rainbow.

ERIC Educational Resources Information Center

Okocha, Aneneosa A.

Super's life-span life-space theory offers a developmental framework for career counseling. This paper provides a brief overview of Super's theory of Life Career Rainbow (LCR) segment. The LCR feature is useful for identifying the stage of a client's career development and in formulating goals for counseling. The assessment is accomplished by…

Integrating Varieties of Life Course Concepts

PubMed Central

2012-01-01

A body of work referred to as the “life course” framework (also known as “life course theory,” the “life course paradigm,” and the “life course perspective”) has been increasingly used to motivate and justify the examination of the relationships among variables in social and behavioral science, particularly in the study of population health and aging. Yet, there is very little agreement on what some of these concepts mean, and there is hardly any agreement on what the “life course” is. This article focuses on the different ways in which the concept of “life course” is used in the contemporary study of aging and human development, particularly with regard to health and well-being. Clarification is given for how “life course” is distinguished from “life span” and “life cycle,” among other “life” words. This work reviews the conceptual literature on the life course, beginning with its formative years in the 1960s and 1970s, through to the present time. Detailed research of several literatures across disciplines revealed five different uses of the term “life course”: (a) life course as time or age, (b) life course as life stages, (c) life course as events, transitions, and trajectories, (d) life course as life-span human development, and (e) life course as early life influences (and their cumulation) on later adult outcomes. To the extent the concept of life course has a multiplicity of meanings that are at variance with one another, this is problematic, as communication is thereby hindered. On the other hand, to the extent the concept of life course involves a rich tapestry of different emphases, this is a good thing, and the diversity of meanings should be retained. This paper proposes a conceptual integration based in part on Riley’s age stratification model that resolves the various meanings of life course into one general framework. Coupled with a demographic conceptualization of the life course, this framework embeds the concept of “life course” within a broader perspective of life-span development. This framework is proposed as an integrated perspective for studying the causes and consequences of “life course events and transitions” and understanding the manner by which “life events” and the role transitions they signify influence the life-span development of outcomes of interest across stages of the life cycle. PMID:22399576

Life-span Socioeconomic Trajectory, Nativity, and Cognitive Aging in Mexican Americans: The Sacramento Area Latino Study on Aging

PubMed Central

Zeki Al-Hazzouri, Adina; Aiello, Allison E.

2011-01-01

Objectives. Early life circumstances influence health across the life span. Migration and ethnicity may modify the lifetime trajectory of socioeconomic status (SES) and lead to heterogeneity in cognitive aging in later life. Methods. We examined the effects of both lifetime socioeconomic trajectory and cumulative disadvantage from childhood through adulthood on late life cognitive performance in a 9-year cohort of 1,789 Mexican Americans aged 60–100 years in 1998–1999. Results. Compared with those with low SES sustained over the life course, we found that those with more advantaged lifetime SES trajectories experienced fewer declines on a test of global cognitive function and a short-term verbal memory test. These associations are larger in first- and second-generation immigrant families. Discussion. Heterogeneity of cognitive aging among diverse race/ethnic groups may be influenced by intergenerational changes in SES, cultural norms, and behaviors and changes in health related to changes in the social and physical environment. PMID:21743044

Life-span socioeconomic trajectory, nativity, and cognitive aging in Mexican Americans: the Sacramento Area Latino Study on Aging.

PubMed

Haan, Mary N; Zeki Al-Hazzouri, Adina; Aiello, Allison E

2011-07-01

Early life circumstances influence health across the life span. Migration and ethnicity may modify the lifetime trajectory of socioeconomic status (SES) and lead to heterogeneity in cognitive aging in later life. We examined the effects of both lifetime socioeconomic trajectory and cumulative disadvantage from childhood through adulthood on late life cognitive performance in a 9-year cohort of 1,789 Mexican Americans aged 60-100 years in 1998-1999. Compared with those with low SES sustained over the life course, we found that those with more advantaged lifetime SES trajectories experienced fewer declines on a test of global cognitive function and a short-term verbal memory test. These associations are larger in first- and second-generation immigrant families. Heterogeneity of cognitive aging among diverse race/ethnic groups may be influenced by intergenerational changes in SES, cultural norms, and behaviors and changes in health related to changes in the social and physical environment.

Addiction research centres and the nurturing of creativity. University of Michigan Addiction Research Center (UMARC): development, evolution, and direction.

PubMed

Zucker, Robert A

2010-06-01

A historical summary is provided of the evolution of the University of Michigan Addiction Research Center (UMARC) since its origins in 1988. Begun as an National Institutes of Health (NIH) research center within a Department of Psychiatry and focused solely upon alcohol and aging, early work emphasized treatment efficacy, differential outcome studies and characterization of the neurophysiological and behavioral manifestations of chronic alcoholism. Over the last 15 years, UMARC has extended its research focus along a number of dimensions: its developmental reach has been extended etiologically by studies of risk early in the life span, and by way of work on earlier screening and the development of early, brief treatment interventions. The addiction focus has expanded to include other drugs of abuse. Levels of analysis have also broadened, with work on the molecular genetics and brain neurophysiology underlying addictive processes, on one hand, and examination of the role of the social environment in long-term course of disorder on the other hand. Activities have been facilitated by several research training programs and by collaborative relationships with other universities around the United States and in Poland. Since 2002, a program for research infrastructure development and collaboration has been ongoing, initially with Poland and more recently with Ukraine, Latvia and Slovakia. A blueprint for the future includes expanded characterization of the neurobiology and genetics of addictive processes, the developmental environment, as well as programmatic work to address the public health implications of our ability to identify risk for disorder very early in life.

A universal molecular clock of protein folds and its power in tracing the early history of aerobic metabolism and planet oxygenation.

PubMed

Wang, Minglei; Jiang, Ying-Ying; Kim, Kyung Mo; Qu, Ge; Ji, Hong-Fang; Mittenthal, Jay E; Zhang, Hong-Yu; Caetano-Anollés, Gustavo

2011-01-01

The standard molecular clock describes a constant rate of molecular evolution and provides a powerful framework for evolutionary timescales. Here, we describe the existence and implications of a molecular clock of folds, a universal recurrence in the discovery of new structures in the world of proteins. Using a phylogenomic structural census in hundreds of proteomes, we build phylogenies and time lines of domains at fold and fold superfamily levels of structural complexity. These time lines correlate approximately linearly with geological timescales and were here used to date two crucial events in life history, planet oxygenation and organism diversification. We first dissected the structures and functions of enzymes in simulated metabolic networks. The placement of anaerobic and aerobic enzymes in the time line revealed that aerobic metabolism emerged about 2.9 billion years (giga-annum; Ga) ago and expanded during a period of about 400 My, reaching what is known as the Great Oxidation Event. During this period, enzymes recruited old and new folds for oxygen-mediated enzymatic activities. Remarkably, the first fold lost by a superkingdom disappeared in Archaea 2.6 Ga ago, within the span of oxygen rise, suggesting that oxygen also triggered diversification of life. The implications of a molecular clock of folds are many and important for the neutral theory of molecular evolution and for understanding the growth and diversity of the protein world. The clock also extends the standard concept that was specific to molecules and their timescales and turns it into a universal timescale-generating tool.

Addiction research centres and the nurturing of creativity: University of Michigan Addiction Research Center (UMARC): Development, Evolution, and Direction

PubMed Central

Zucker, Robert A.

2010-01-01

A historical summary is provided of the evolution of the University of Michigan Addiction Research Center (UMARC) since its origins in 1988. Begun as an NIH research center within a Department of Psychiatry and focused solely on alcohol and aging, early work emphasized treatment efficacy, differential outcome studies, and characterization of the neurophysiological and behavioral manifestations of chronic alcoholism. Over the last fifteen years, UMARC has extended its research focus along a number of dimensions: Its developmental reach has been extended etiologically by studies of risk early in the life span, and by way of work on earlier screening and the development of early, brief treatment interventions. The addiction focus has expanded to include other drugs of abuse. Levels of analysis have also broadened, with work on the molecular genetics and brain neurophysiology underlying addictive processes on the one hand, and examination of the role of the social environment in long term course of disorder on the other. Activities have been facilitated by several research training programs and by collaborative relationships with other universities around the United States and in Poland. Since 2002, a program for research infrastructure development and collaboration has been carried on, initially with Poland and more recently with Ukraine, Latvia, and Slovakia. A blueprint for the future includes expanded characterization of the neurobiology and genetics of addictive processes, the developmental environment, as well as programmatic work to address the public health implications of our ability to identify risk for disorder very early in life. PMID:20331547

Evolution of insect proteomes: insights into synapse organization and synaptic vesicle life cycle

PubMed Central

Yanay, Chava; Morpurgo, Noa; Linial, Michal

2008-01-01

Background The molecular components in synapses that are essential to the life cycle of synaptic vesicles are well characterized. Nonetheless, many aspects of synaptic processes, in particular how they relate to complex behaviour, remain elusive. The genomes of flies, mosquitoes, the honeybee and the beetle are now fully sequenced and span an evolutionary breadth of about 350 million years; this provides a unique opportunity to conduct a comparative genomics study of the synapse. Results We compiled a list of 120 gene prototypes that comprise the core of presynaptic structures in insects. Insects lack several scaffolding proteins in the active zone, such as bassoon and piccollo, and the most abundant protein in the mammalian synaptic vesicle, namely synaptophysin. The pattern of evolution of synaptic protein complexes is analyzed. According to this analysis, the components of presynaptic complexes as well as proteins that take part in organelle biogenesis are tightly coordinated. Most synaptic proteins are involved in rich protein interaction networks. Overall, the number of interacting proteins and the degrees of sequence conservation between human and insects are closely correlated. Such a correlation holds for exocytotic but not for endocytotic proteins. Conclusion This comparative study of human with insects sheds light on the composition and assembly of protein complexes in the synapse. Specifically, the nature of the protein interaction graphs differentiate exocytotic from endocytotic proteins and suggest unique evolutionary constraints for each set. General principles in the design of proteins of the presynaptic site can be inferred from a comparative study of human and insect genomes. PMID:18257909

17. DETAIL OF SOUTH PORTAL, SHOWING "TREE OF LIFE" RAILING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. DETAIL OF SOUTH PORTAL, SHOWING "TREE OF LIFE" RAILING DETAIL AS WELL AS BUILDER'S PLATE. - Falls Bridge, Spanning Schuylkill River, connecting East & West River Drives, Philadelphia, Philadelphia County, PA

Life Satisfaction, Self-Esteem, and Subjective Age in Women across the Life Span

ERIC Educational Resources Information Center

Borzumato-Gainey, Christine; Kennedy, Alison; McCabe, Beth; Degges-White, Suzanne

2009-01-01

A study of 320 women, ages 21 to 69, explored the relations among relationship status, subjective age, self-esteem, and life satisfaction. Women in married or partnered relationships had higher levels of life satisfaction than did single women. Women in their 30s and 40s had significantly lower levels of life satisfaction than did other age…

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions

PubMed Central

2012-01-01

Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercetin and resveratrol have negative impacts on CLS under winemaking conditions, an unexpected behavior for these potential anti-oxidants. We observed that quercetin inhibits alcohol and aldehyde dehydrogenase activities, and that resveratrol performs a pro-oxidant role during grape juice fermentation. Vitamins nicotinic acid and nicotinamide are precursors of NAD+, and their addition reduces mean longevity during fermentation, suggesting a metabolic unbalance negative for CLS. Moreover, vitamin mix supplementation at the end of fermentation shortens CLS and enhances cell lysis, while amino acids increase life span. Conclusions Wine S. cerevisiae strains are able to sense changes in the environmental conditions and adapt their longevity to them. Yeast death is influenced by the conditions present at the end of wine fermentation, particularly by the concentration of two-carbon metabolites produced by the fermentative metabolism, such as ethanol, acetic acid and acetaldehyde, and also by the grape juice composition, particularly its vitamin content. PMID:22873488

Normative personality trait development in adulthood: A 6-year cohort-sequential growth model.

PubMed

Milojev, Petar; Sibley, Chris G

2017-03-01

The present study investigated patterns of normative change in personality traits across the adult life span (19 through 74 years of age). We examined change in extraversion, agreeableness, conscientiousness, neuroticism, openness to experience and honesty-humility using data from the first 6 annual waves of the New Zealand Attitudes and Values Study (N = 10,416; 61.1% female, average age = 49.46). We present a cohort-sequential latent growth model assessing patterns of mean-level change due to both aging and cohort effects. Extraversion decreased as people aged, with the most pronounced declines occurring in young adulthood, and then again in old age. Agreeableness, indexed with a measure focusing on empathy, decreased in young adulthood and remained relatively unchanged thereafter. Conscientiousness increased among young adults then leveled off and remained fairly consistent for the rest of the adult life span. Neuroticism and openness to experience decreased as people aged. However, the models suggest that these latter effects may also be partially due to cohort differences, as older people showed lower levels of neuroticism and openness to experience more generally. Honesty-humility showed a pronounced and consistent increase across the adult life span. These analyses of large-scale longitudinal national probability panel data indicate that different dimensions of personality follow distinct developmental processes throughout adulthood. Our findings also highlight the importance of young adulthood (up to about the age of 30) in personality trait development, as well as continuing change throughout the adult life span. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Dietary consumption of monosodium L-glutamate induces adaptive response and reduction in the life span of Drosophila melanogaster.

PubMed

Abolaji, Amos O; Olaiya, Charles O; Oluwadahunsi, Oluwagbenga J; Farombi, Ebenezer O

2017-04-01

Adaptive response is the ability of an organism to better counterattack stress-induced damage in response to a number of different cytotoxic agents. Monosodium L-glutamate (MSG), the sodium salt of amino acid glutamate, is commonly used as a food additive. We investigated the effects of MSG on the life span and antioxidant response in Drosophila melanogaster (D. melanogaster). Both genders (1 to 3 days old) of flies were fed with diet containing MSG (0.1, 0.5, and 2.5-g/kg diet) for 5 days to assess selected antioxidant and oxidative stress markers, while flies for longevity were fed for lifetime. Thereafter, the longevity assay, hydrogen peroxide (H 2 O 2 ), and reactive oxygen and nitrogen species levels were determined. Also, catalase, glutathione S-transferase and acetylcholinesterase activities, and total thiol content were evaluated in the flies. We found that MSG reduced the life span of the flies by up to 23% after continuous exposure. Also, MSG increased reactive oxygen and nitrogen species and H 2 O 2 generations and total thiol content as well as the activities of catalase and glutathione S-transferase in D. melanogaster (P < .05). In conclusion, consumption of MSG for 5 days by D. melanogaster induced adaptive response, but long-term exposure reduced life span of flies. This study may therefore have public health significance in humans, and thus, moderate consumption of MSG is advocated by the authors. Copyright © 2017 John Wiley & Sons, Ltd.

Circadian clocks govern calorie restriction-mediated life span extension through BMAL1- and IGF-1-dependent mechanisms.

PubMed

Patel, Sonal A; Chaudhari, Amol; Gupta, Richa; Velingkaar, Nikkhil; Kondratov, Roman V

2016-04-01

Calorie restriction (CR) increases longevity in many species by unknown mechanisms. The circadian clock was proposed as a potential mediator of CR. Deficiency of the core component of the circadian clock-transcriptional factor BMAL1 (brain and muscle ARNT [aryl hydrocarbon receptor nuclear translocator]-like protein 1)-results in accelerated aging. Here we investigated the role of BMAL1 in mechanisms of CR. The 30% CR diet increased the life span of wild-type (WT) mice by 20% compared to mice on anad libitum(AL) diet but failed to increase life span ofBmal1(-/-)mice. BMAL1 deficiency impaired CR-mediated changes in the plasma levels of IGF-1 and insulin. We detected a statistically significantly reduction of IGF-1 in CRvs.AL by 50 to 70% in WT mice at several daily time points tested, while inBmal1(-/-)the reduction was not significant. Insulin levels in WT were reduced by 5 to 9%, whileBmal1(-/-)induced it by 10 to 35% at all time points tested. CR up-regulated the daily average expression ofBmal1(by 150%) and its downstream target genesPeriods(by 470% forPer1and by 130% forPer2). We propose that BMAL1 is an important mediator of CR, and activation of BMAL1 might link CR mechanisms with biologic clocks.-Patel, S. A., Chaudhari, A., Gupta, R., Velingkaar, N., Kondratov, R. V. Circadian clocks govern calorie restriction-mediated life span extension through BMAL1- and IGF-1-dependent mechanisms. © FASEB.

Physical Activity Throughout the Adult Life Span and Domain-Specific Cognitive Function in Old Age: A Systematic Review of Cross-Sectional and Longitudinal Data.

PubMed

Engeroff, Tobias; Ingmann, Tobias; Banzer, Winfried

2018-06-01

A growing body of literature suggests that physical activity might alleviate the age-related neurodegeneration and decline of cognitive function. However, most of this evidence is based on data investigating the association of exercise interventions or current physical activity behavior with cognitive function in elderly subjects. We performed a systematic review and hypothesize that physical activity during the adult life span is connected with maintained domain-specific cognitive functions during late adulthood defined as age 60+ years. We performed a systematic literature search up to November 2017 in PubMed, Web of Science, and Google Scholar without language limitations for studies analyzing the association of leisure physical activity during the adult life span (age 18+ years) and domain-specific cognitive functions in older adults (age 60+ years). The literature review yielded 14,294 articles and after applying inclusion and exclusion criteria, nine cross-sectional and 14 longitudinal studies were included. Moderate- and vigorous-intensity leisure physical activity was associated with global cognitive function and specific cognitive domains including executive functions and memory but not attention or working memory. Most studies assessed mid- to late-adulthood physical activity, thus information concerning the influence of young adult life-span physical activity is currently lacking. Observational evidence that moderate- and vigorous-intensity leisure physical activity is beneficially associated with maintained cognitive functions during old age is accumulating. Further studies are necessary to confirm a causal link by assessing objective physical activity data and the decline of cognitive functions at multiple time points during old age.

Stable knockdown of PASG enhances DNA demethylation but does not accelerate cellular senescence in TIG-7 human fibroblasts

PubMed Central

Suzuki, Toshikazu; Farrar, Jason E.; Yegnasubramanian, Srinivasan; Zahed, Muhammed; Suzuki, Nobuo; Arceci, Robert J.

2009-01-01

Demethylation of 5-methylcytosine in genomic DNA is believed to be one of the mechanisms underlying replicative life-span of mammalian cells. Both proliferation associated SNF2-like gene (PASG, also termed Lsh) and DNA methyltransferase 3B (Dnmt3b) knockout mice result in embryonic genomic hypomethylation and a replicative senescent phenotype. However, it is unclear whether gradual demethylation of DNA during somatic cell division is directly involved in senescence. In this study, we retrovirally transduced TIG-7 human fibroblasts with a shRNA against PASG and compared the rate of change in DNA methylation as well as the replicative life-span to control cells under low (3%) and ambient (20%) oxygen. Expression of PASG protein was decreased by approximately 80% compared to control cells following transduction of PASG shRNA gene. The rate of cell growth was the same in both control and PASG-suppressed cells. The rate of demethylation of DNA was significantly increased in PASG-suppressed cells as compared control cells. However, decreased PASG expression did not shorten the replicative life-span of TIG-7 cells. Culture under low oxygen extended the life-span of TIG-7 cells but did not alter the rate of DNA demethylation. While knockout of PASG during development results in genomic hypomethylation and premature senescence, our results show that while downregulation of PASG expression in a somatic cell also leads to DNA hypomethylation, there is no associated senescent phenotype. These results suggest differences in cellular consequences of hypomethylation mediated by PASG during development compared to that in somatic cells. PMID:18948754

Stable knockdown of PASG enhances DNA demethylation but does not accelerate cellular senescence in TIG-7 human fibroblasts.

PubMed

Suzuki, Toshikazu; Farrar, Jason E; Yegnasubramanian, Srinivasan; Zahed, Muhammed; Suzuki, Nobuo; Arceci, Robert J

2008-09-01

Demethylation of 5-methylcytosine in genomic DNA is believed to be one of the mechanisms underlying replicative life-span of mammalian cells. Both proliferation associated SNF2-like gene (PASG, also termed Lsh) and DNA methyltransferase 3B (Dnmt3b) knockout mice result in embryonic genomic hypomethylation and a replicative senescent phenotype. However, it is unclear whether gradual demethylation of DNA during somatic cell division is directly involved in senescence. In this study, we retrovirally transduced TIG-7 human fibroblasts with a shRNA against PASG and compared the rate of change in DNA methylation as well as the replicative life-span to control cells under low (3%) and ambient (20%) oxygen. Expression of PASG protein was decreased by approximately 80% compared to control cells following transduction of PASG shRNA gene. The rate of cell growth was the same in both control and PASG-suppressed cells. The rate of demethylation of DNA was significantly increased in PASG-suppressed cells as compared control cells. However, decreased PASG expression did not shorten the replicative life-span of TIG-7 cells. Culture under low oxygen extended the life-span of TIG-7 cells but did not alter the rate of DNA demethylation. While knockout of PASG during development results in genomic hypomethylation and premature senescence, our results show that while downregulation of PASG expression in a somatic cell also leads to DNA hypomethylation, there is no associated senescent phenotype. These results suggest differences in cellular consequences of hypomethylation mediated by PASG during development compared to that in somatic cells.

The archaebacterial origin of eukaryotes.

PubMed

Cox, Cymon J; Foster, Peter G; Hirt, Robert P; Harris, Simon R; Embley, T Martin

2008-12-23

The origin of the eukaryotic genetic apparatus is thought to be central to understanding the evolution of the eukaryotic cell. Disagreement about the source of the relevant genes has spawned competing hypotheses for the origins of the eukaryote nuclear lineage. The iconic rooted 3-domains tree of life shows eukaryotes and archaebacteria as separate groups that share a common ancestor to the exclusion of eubacteria. By contrast, the eocyte hypothesis has eukaryotes originating within the archaebacteria and sharing a common ancestor with a particular group called the Crenarchaeota or eocytes. Here, we have investigated the relative support for each hypothesis from analysis of 53 genes spanning the 3 domains, including essential components of the eukaryotic nucleic acid replication, transcription, and translation apparatus. As an important component of our analysis, we investigated the fit between model and data with respect to composition. Compositional heterogeneity is a pervasive problem for reconstruction of ancient relationships, which, if ignored, can produce an incorrect tree with strong support. To mitigate its effects, we used phylogenetic models that allow for changing nucleotide or amino acid compositions over the tree and data. Our analyses favor a topology that supports the eocyte hypothesis rather than archaebacterial monophyly and the 3-domains tree of life.

A congruent phylogenomic signal places eukaryotes within the Archaea.

PubMed

Williams, Tom A; Foster, Peter G; Nye, Tom M W; Cox, Cymon J; Embley, T Martin

2012-12-22

Determining the relationships among the major groups of cellular life is important for understanding the evolution of biological diversity, but is difficult given the enormous time spans involved. In the textbook 'three domains' tree based on informational genes, eukaryotes and Archaea share a common ancestor to the exclusion of Bacteria. However, some phylogenetic analyses of the same data have placed eukaryotes within the Archaea, as the nearest relatives of different archaeal lineages. We compared the support for these competing hypotheses using sophisticated phylogenetic methods and an improved sampling of archaeal biodiversity. We also employed both new and existing tests of phylogenetic congruence to explore the level of uncertainty and conflict in the data. Our analyses suggested that much of the observed incongruence is weakly supported or associated with poorly fitting evolutionary models. All of our phylogenetic analyses, whether on small subunit and large subunit ribosomal RNA or concatenated protein-coding genes, recovered a monophyletic group containing eukaryotes and the TACK archaeal superphylum comprising the Thaumarchaeota, Aigarchaeota, Crenarchaeota and Korarchaeota. Hence, while our results provide no support for the iconic three-domain tree of life, they are consistent with an extended eocyte hypothesis whereby vital components of the eukaryotic nuclear lineage originated from within the archaeal radiation.

Decades of field data reveal that turtles senesce in the wild

PubMed Central

Warner, Daniel A.; Miller, David A. W.; Bronikowski, Anne M.; Janzen, Fredric J.

2016-01-01

Lifespan and aging rates vary considerably across taxa; thus, understanding the factors that lead to this variation is a primary goal in biology and has ramifications for understanding constraints and flexibility in human aging. Theory predicts that senescence—declining reproduction and increasing mortality with advancing age—evolves when selection against harmful mutations is weaker at old ages relative to young ages or when selection favors pleiotropic alleles with beneficial effects early in life despite late-life costs. However, in many long-lived ectotherms, selection is expected to remain strong at old ages because reproductive output typically increases with age, which may lead to the evolution of slow or even negligible senescence. We show that, contrary to current thinking, both reproduction and survival decline with adult age in the painted turtle, Chrysemys picta, based on data spanning >20 y from a wild population. Older females, despite relatively high reproductive output, produced eggs with reduced hatching success. Additionally, age-specific mark–recapture analyses revealed increasing mortality with advancing adult age. These findings of reproductive and mortality senescence challenge the contention that chelonians do not age and more generally provide evidence of reduced fitness at old ages in nonmammalian species that exhibit long chronological lifespans. PMID:27140634

Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shitara, Shingo; Kakeda, Minoru; Nagata, Keiko

2008-05-09

Telomerase-mediated life-span extension enables the expansion of normal cells without malignant transformation, and thus has been thought to be useful in cell therapies. Currently, integrating vectors including the retrovirus are used for human telomerase reverse transcriptase (hTERT)-mediated expansion of normal cells; however, the use of these vectors potentially causes unexpected insertional mutagenesis and/or activation of oncogenes. Here, we established normal human fibroblast (hPF) clones retaining non-integrating human artificial chromosome (HAC) vectors harboring the hTERT expression cassette. In hTERT-HAC/hPF clones, we observed the telomerase activity and the suppression of senescent-associated SA-{beta}-galactosidase activity. Furthermore, the hTERT-HAC/hPF clones continued growing beyond 120 daysmore » after cloning, whereas the hPF clones retaining the silent hTERT-HAC senesced within 70 days. Thus, hTERT-HAC-mediated episomal expression of hTERT allows the extension of the life-span of human primary cells, implying that gene delivery by non-integrating HAC vectors can be used to control cellular proliferative capacity of primary cultured cells.« less

Life-span development of visual working memory: when is feature binding difficult?

PubMed

Cowan, Nelson; Naveh-Benjamin, Moshe; Kilb, Angela; Saults, J Scott

2006-11-01

We asked whether the ability to keep in working memory the binding between a visual object and its spatial location changes with development across the life span more than memory for item information. Paired arrays of colored squares were identical or differed in the color of one square, and in the latter case, the changed color was unique on that trial (item change) or was duplicated elsewhere in the array (color-location binding change). Children (8-10 and 11-12 years old) and older adults (65-85 years old) showed deficits relative to young adults. These were only partly simulated by dividing attention in young adults. The older adults had an additional deficiency, specifically in binding information, which was evident only when item- and binding-change trials were mixed together. In that situation, the older adults often overlooked the more subtle, binding-type changes. Some working memory processes related to binding undergo life-span development in an inverted-U shape, whereas other, bias- and salience-related processes that influence the use of binding information seem to develop monotonically.

Taste bud cell dynamics during normal and sodium-restricted development.

PubMed

Hendricks, Susan J; Brunjes, Peter C; Hill, David L

2004-04-26

Taste bud volume increases over the postnatal period to match the number of neurons providing innervation. To clarify age-related changes in fungiform taste bud volume, the current study investigated developmental changes in taste bud cell number, proliferation rate, and life span. Taste bud growth can largely be accounted for by addition of cytokeratin-19-positive taste bud cells. Examination of taste bud cell kinetics with 3H-thymidine autoradiography revealed that cell life span and turnover periods were not altered during normal development but that cells were produced more rapidly in young rats, a prominent modification that could lead to increased taste bud size. By comparison, dietary sodium restriction instituted during pre- and postnatal development results in small taste buds at adulthood as a result of fewer cytokeratin-19-positive cells. The dietary manipulation also had profound influences on taste bud growth kinetics, including an increased latency for cells to enter the taste bud and longer life span and turnover periods. These studies provide fundamental, new information about taste bud development under normal conditions and after environmental manipulations that impact nerve/target matching. Copyright 2004 Wiley-Liss, Inc.

Lung glutathione reductase induction in aging catalase-depleted frogs correlates with early survival throughout the life span.

PubMed

Perez-Campo, R; Lopez-Torres, M; Rojas, C; Cadenas, S; Barja de Quiroga, G

1993-02-01

A comprehensive experimental study on free radical-related parameters was performed in the lung throughout the life span of 220 initially young or old frogs. No age related differences were found transversely or longitudinally for lung superoxide dismutase, catalase, Se-dependent and -independent glutathione peroxidases, glutathione reductase, GSH, GSSG, or GSSG/GSH ratio. Continuous catalase depletion with aminotriazole led to glutathione reductase induction in the lung after 14.5 months of experimentation. This was accompanied by a great increase in survival rate of treated animals in relation to controls (especially in the old group). After 26.5 months of experimentation, glutathione reductase induction was lost and GSSG/GSH values tended to increase. This was followed by a 3-month long period of acute decrease in survival rate of treated animals. It is suggested that a high antioxidant/prooxidant balance is of protective value against causes of early death and can possibly be used in the future (when appropriately controlled) to increase the number of healthy years of the normal life span.

DNA damage leads to progressive replicative decline but extends the life span of long-lived mutant animals.

PubMed

Lans, H; Lindvall, J M; Thijssen, K; Karambelas, A E; Cupac, D; Fensgård, O; Jansen, G; Hoeijmakers, J H J; Nilsen, H; Vermeulen, W

2013-12-01

Human-nucleotide-excision repair (NER) deficiency leads to different developmental and segmental progeroid symptoms of which the pathogenesis is only partially understood. To understand the biological impact of accumulating spontaneous DNA damage, we studied the phenotypic consequences of DNA-repair deficiency in Caenorhabditis elegans. We find that DNA damage accumulation does not decrease the adult life span of post-mitotic tissue. Surprisingly, loss of functional ERCC-1/XPF even further extends the life span of long-lived daf-2 mutants, likely through an adaptive activation of stress signaling. Contrariwise, NER deficiency leads to a striking transgenerational decline in replicative capacity and viability of proliferating cells. DNA damage accumulation induces severe, stochastic impairment of development and growth, which is most pronounced in NER mutants that are also impaired in their response to ionizing radiation and inter-strand crosslinks. These results suggest that multiple DNA-repair pathways can protect against replicative decline and indicate that there might be a direct link between the severity of symptoms and the level of DNA-repair deficiency in patients.

Age trends for failures of sustained attention.

PubMed

Carriere, Jonathan S A; Cheyne, J Allan; Solman, Grayden J F; Smilek, Daniel

2010-09-01

Recent research has revealed an age-related reduction in errors in a sustained attention task, suggesting that sustained attention abilities improve with age. Such results seem paradoxical in light of the well-documented age-related declines in cognitive performance. In the present study, performance on the sustained attention to response task (SART) was assessed in a supplemented archival sample of 638 individuals between 14 and 77 years old. SART errors and response speed appeared to decline in a linear fashion as a function of age throughout the age span studied. In contrast, other measures of sustained attention (reaction time coefficient of variation), anticipation, and omissions) showed a decrease early in life and then remained unchanged for the rest of the life span. Thus, sustained attention shows improvements with maturation in early adulthood but then does not change with aging in older adults. On the other hand, aging across the entire life span leads to a more strategic (i.e., slower) response style that reduces the overt and critical consequences (i.e., SART errors) of momentary task disengagement. (c) 2010 APA, all rights reserved.

Insights from comparative analyses of aging in birds and mammals.

PubMed

Ricklefs, Robert E

2010-04-01

Many laboratory models used in aging research are inappropriate for understanding senescence in mammals, including humans, because of fundamental differences in life history, maintenance in artificial environments, and selection for early aging and high reproductive rate. Comparative studies of senescence in birds and mammals reveal a broad range in rates of aging among a variety of taxa with similar physiology and patterns of development. These comparisons suggest that senescence is a shared property of all vertebrates with determinate growth, that the rate of senescence has been modified by evolution in response to the potential life span allowed by extrinsic mortality factors, and that most variation among species in the rate of senescence is independent of commonly ascribed causes of aging, such as oxidative damage. Individuals of potentially long-lived species, particularly birds, appear to maintain high condition to near the end of life. Because most individuals in natural populations of such species die of aging-related causes, these populations likely harbor little genetic variation for mechanisms that could extend life further, or these mechanisms are very costly. This, and the apparent evolutionary conservatism in the rate of increase in mortality with age, suggests that variation in the rate of senescence reflects fundamental changes in organism structure, likely associated with the rate of development, rather than physiological or biochemical processes influenced by a few genes. Understanding these evolved differences between long-lived and short-lived organisms would seem to be an essential foundation for designing therapeutic interventions with respect to human aging and longevity.

The Evolution and Stability of Massive Stars

NASA Astrophysics Data System (ADS)

Shiode, Joshua Hajime

Massive stars are the ultimate source for nearly all the elements necessary for life. The first stars forge these elements from the sparse set of ingredients supplied by the Big Bang, and distribute enriched ashes throughout their galactic homes via their winds and explosive deaths. Subsequent generations follow suit, assembling from the enriched ashes of their predecessors. Over the last several decades, the astrophysics community has developed a sophisticated theoretical picture of the evolution of these stars, but it remains an incomplete accounting of the rich set of observations. Using state of the art models of massive stars, I have investigated the internal processes taking place throughout the life-cycles of stars spanning those from the first generation ("Population III") to the present-day ("Population I"). I will argue that early-generation stars were not highly unstable to perturbations, contrary to a host of past investigations, if a correct accounting is made for the viscous effect of convection. For later generations, those with near solar metallicity, I find that this very same convection may excite gravity-mode oscillations that produce observable brightness variations at the stellar surface when the stars are near the main sequence. If confirmed with modern high-precision monitoring experiments, like Kepler and CoRoT, the properties of observed gravity modes in massive stars could provide a direct probe of the poorly constrained physics of gravity mode excitation by convection. Finally, jumping forward in stellar evolutionary time, I propose and explore an entirely new mechanism to explain the giant eruptions observed and inferred to occur during the final phases of massive stellar evolution. This mechanism taps into the vast nuclear fusion luminosity, and accompanying convective luminosity, in the stellar core to excite waves capable of carrying a super-Eddington luminosity out to the stellar envelope. This energy transfer from the core to the envelope has the potential to unbind a significant amount of mass in close proximity to a star's eventual explosion as a core collapse supernova.

Does telomere elongation lead to a longer lifespan if cancer is considered?

NASA Astrophysics Data System (ADS)

Masa, Michael; Cebrat, Stanisław; Stauffer, Dietrich

2006-05-01

As cell proliferation is limited due to the loss of telomere repeats in DNA of normal somatic cells during division, telomere attrition can possibly play an important role in determining the maximum life span of organisms as well as contribute to the process of biological ageing. With computer simulations of cell culture development in organisms, which consist of tissues of normal somatic cells with finite growth, we obtain an increase of life span and life expectancy for longer telomeric DNA in the zygote. By additionally considering a two-mutation model for carcinogenesis and indefinite proliferation by the activation of telomerase, we demonstrate that the risk of dying due to cancer can outweigh the positive effect of longer telomeres on the longevity.

Why Do the Braking Indices of Pulsars Span a Range of More Than 100 Millions?

NASA Astrophysics Data System (ADS)

Zhang, Shuang-Nan; Xie, Yi

2012-12-01

Here we report that the observed braking indices of the 366 pulsars in the sample of Hobbs et al. range from about -108 to about +108 and are significantly correlated with their characteristic ages. Using the model of magnetic field evolution we developed previously based on the same data, we derive an analytical expression for the braking index which agrees with all the observed statistical properties of the braking indices of the pulsars in the sample of Hobbs et al. Our model is, however, incompatible with the previous interpretation that magnetic field growth is responsible for the small values of braking indices (<3) observed for "baby" pulsars with characteristic ages of less than 2 × 103 yr. We find that the "instantaneous" braking index of a pulsar may be different from the "averaged" braking index obtained from fitting the data over a certain time span. The close match between our model-predicted "instantaneous" braking indices and the observed "averaged" braking indices suggests that the time spans used previously are usually smaller than or comparable to their magnetic field oscillation periods. Our model can be tested with the existing data by calculating the braking index as a function of the time span for each pulsar. In doing so, one can obtain for each pulsar all the parameters in our magnetic field evolution model, and may be able to improve the sensitivity of using pulsars to detect gravitational waves.

From dinosaurs to modern bird diversity: extending the time scale of adaptive radiation.

PubMed

Moen, Daniel; Morlon, Hélène

2014-05-01

What explains why some groups of organisms, like birds, are so species rich? And what explains their extraordinary ecological diversity, ranging from large, flightless birds to small migratory species that fly thousand of kilometers every year? These and similar questions have spurred great interest in adaptive radiation, the diversification of ecological traits in a rapidly speciating group of organisms. Although the initial formulation of modern concepts of adaptive radiation arose from consideration of the fossil record, rigorous attempts to identify adaptive radiation in the fossil record are still uncommon. Moreover, most studies of adaptive radiation concern groups that are less than 50 million years old. Thus, it is unclear how important adaptive radiation is over temporal scales that span much larger portions of the history of life. In this issue, Benson et al. test the idea of a "deep-time" adaptive radiation in dinosaurs, compiling and using one of the most comprehensive phylogenetic and body-size datasets for fossils. Using recent phylogenetic statistical methods, they find that in most clades of dinosaurs there is a strong signal of an "early burst" in body-size evolution, a predicted pattern of adaptive radiation in which rapid trait evolution happens early in a group's history and then slows down. They also find that body-size evolution did not slow down in the lineage leading to birds, hinting at why birds survived to the present day and diversified. This paper represents one of the most convincing attempts at understanding deep-time adaptive radiations.

Singular features of fertilization and their impact on the male reproductive system in eutherian mammals.

PubMed

Bedford, J Michael

2014-02-01

Therian (marsupial and eutherian) mammals have evolved a suite of novel reproductive features - seen variously in their gametes, the steps of fertilization and the male reproductive tract - whose adaptive significance remains unclear. Present evidence for the better-understood eutherian mammals suggests that the 'prime mover' in their evolution has been the character of the egg coat, with other such features being adaptations to the consequences of this. Its elastic thickness allows the zona pellucida to stretch to a variable degree and yet remain around the blastocyst during much or all of its expansion before implantation, but its character represents an unusual challenge for spermatozoa. Novel aspects of the acrosome related to this challenge enable it to maintain a relatively prolonged binding after the onset of the acrosome reaction, and the structure, shape and behaviour of the sperm head point to physical thrust as a major element of zona penetration - with the unique configuration of gamete fusion as a sequela of this strategy. In the male, such adaptations are reflected in sperm head formation in the testis and in sperm maturation in the epididymis involving at least the sperm head's structure, plasmalemma and acrosome. This complexity allied to a slow epididymal sperm transport, a relatively modest sperm production and the brief life span of mature spermatozoa kept above the cauda epididymidis could account for the evolution of the sperm storage function - a development seemingly linked, in turn, to the need for sperm capacitation and scrotal evolution.

The 4-Celled Tetrabaena socialis Nuclear Genome Reveals the Essential Components for Genetic Control of Cell Number at the Origin of Multicellularity in the Volvocine Lineage.

PubMed

Featherston, Jonathan; Arakaki, Yoko; Hanschen, Erik R; Ferris, Patrick J; Michod, Richard E; Olson, Bradley J S C; Nozaki, Hisayoshi; Durand, Pierre M

2018-04-01

Multicellularity is the premier example of a major evolutionary transition in individuality and was a foundational event in the evolution of macroscopic biodiversity. The volvocine chlorophyte lineage is well suited for studying this process. Extant members span unicellular, simple colonial, and obligate multicellular taxa with germ-soma differentiation. Here, we report the nuclear genome sequence of one of the most morphologically simple organisms in this lineage-the 4-celled colonial Tetrabaena socialis and compare this to the three other complete volvocine nuclear genomes. Using conservative estimates of gene family expansions a minimal set of expanded gene families was identified that associate with the origin of multicellularity. These families are rich in genes related to developmental processes. A subset of these families is lineage specific, which suggests that at a genomic level the evolution of multicellularity also includes lineage-specific molecular developments. Multiple points of evidence associate modifications to the ubiquitin proteasomal pathway (UPP) with the beginning of coloniality. Genes undergoing positive or accelerating selection in the multicellular volvocines were found to be enriched in components of the UPP and gene families gained at the origin of multicellularity include components of the UPP. A defining feature of colonial/multicellular life cycles is the genetic control of cell number. The genomic data presented here, which includes diversification of cell cycle genes and modifications to the UPP, align the genetic components with the evolution of this trait.

The Effects of Role Congruence and Role Conflict on Work, Marital, and Life Satisfaction

ERIC Educational Resources Information Center

Perrone, Kristin M.; Webb, L. Kay; Blalock, Rachel H.

2005-01-01

The impact of role congruence and role conflict on work, marital, and life satisfaction was studied using Super's life-span, life-space theory. A conceptual model of relationships between these variables was proposed, and gender differences were examined. Participants were 35 male and 60 female college graduates who completed surveys by mail.…

Prokaryotic evolution and the tree of life are two different things

PubMed Central

Bapteste, Eric; O'Malley, Maureen A; Beiko, Robert G; Ereshefsky, Marc; Gogarten, J Peter; Franklin-Hall, Laura; Lapointe, François-Joseph; Dupré, John; Dagan, Tal; Boucher, Yan; Martin, William

2009-01-01

Background The concept of a tree of life is prevalent in the evolutionary literature. It stems from attempting to obtain a grand unified natural system that reflects a recurrent process of species and lineage splittings for all forms of life. Traditionally, the discipline of systematics operates in a similar hierarchy of bifurcating (sometimes multifurcating) categories. The assumption of a universal tree of life hinges upon the process of evolution being tree-like throughout all forms of life and all of biological time. In multicellular eukaryotes, the molecular mechanisms and species-level population genetics of variation do indeed mainly cause a tree-like structure over time. In prokaryotes, they do not. Prokaryotic evolution and the tree of life are two different things, and we need to treat them as such, rather than extrapolating from macroscopic life to prokaryotes. In the following we will consider this circumstance from philosophical, scientific, and epistemological perspectives, surmising that phylogeny opted for a single model as a holdover from the Modern Synthesis of evolution. Results It was far easier to envision and defend the concept of a universal tree of life before we had data from genomes. But the belief that prokaryotes are related by such a tree has now become stronger than the data to support it. The monistic concept of a single universal tree of life appears, in the face of genome data, increasingly obsolete. This traditional model to describe evolution is no longer the most scientifically productive position to hold, because of the plurality of evolutionary patterns and mechanisms involved. Forcing a single bifurcating scheme onto prokaryotic evolution disregards the non-tree-like nature of natural variation among prokaryotes and accounts for only a minority of observations from genomes. Conclusion Prokaryotic evolution and the tree of life are two different things. Hence we will briefly set out alternative models to the tree of life to study their evolution. Ultimately, the plurality of evolutionary patterns and mechanisms involved, such as the discontinuity of the process of evolution across the prokaryote-eukaryote divide, summons forth a pluralistic approach to studying evolution. Reviewers This article was reviewed by Ford Doolittle, John Logsdon and Nicolas Galtier. PMID:19788731

Prokaryotic evolution and the tree of life are two different things.

PubMed

Bapteste, Eric; O'Malley, Maureen A; Beiko, Robert G; Ereshefsky, Marc; Gogarten, J Peter; Franklin-Hall, Laura; Lapointe, François-Joseph; Dupré, John; Dagan, Tal; Boucher, Yan; Martin, William

2009-09-29

The concept of a tree of life is prevalent in the evolutionary literature. It stems from attempting to obtain a grand unified natural system that reflects a recurrent process of species and lineage splittings for all forms of life. Traditionally, the discipline of systematics operates in a similar hierarchy of bifurcating (sometimes multifurcating) categories. The assumption of a universal tree of life hinges upon the process of evolution being tree-like throughout all forms of life and all of biological time. In multicellular eukaryotes, the molecular mechanisms and species-level population genetics of variation do indeed mainly cause a tree-like structure over time. In prokaryotes, they do not. Prokaryotic evolution and the tree of life are two different things, and we need to treat them as such, rather than extrapolating from macroscopic life to prokaryotes. In the following we will consider this circumstance from philosophical, scientific, and epistemological perspectives, surmising that phylogeny opted for a single model as a holdover from the Modern Synthesis of evolution. It was far easier to envision and defend the concept of a universal tree of life before we had data from genomes. But the belief that prokaryotes are related by such a tree has now become stronger than the data to support it. The monistic concept of a single universal tree of life appears, in the face of genome data, increasingly obsolete. This traditional model to describe evolution is no longer the most scientifically productive position to hold, because of the plurality of evolutionary patterns and mechanisms involved. Forcing a single bifurcating scheme onto prokaryotic evolution disregards the non-tree-like nature of natural variation among prokaryotes and accounts for only a minority of observations from genomes. Prokaryotic evolution and the tree of life are two different things. Hence we will briefly set out alternative models to the tree of life to study their evolution. Ultimately, the plurality of evolutionary patterns and mechanisms involved, such as the discontinuity of the process of evolution across the prokaryote-eukaryote divide, summons forth a pluralistic approach to studying evolution. This article was reviewed by Ford Doolittle, John Logsdon and Nicolas Galtier.

Publications of the exobiology program for 1990: A special bibliography

NASA Technical Reports Server (NTRS)

1992-01-01

The Exobiology Program is an integrated program designed to investigate and understand those processes related to the origin, evolution, and distribution of life in the universe. The Exobiology Program is broad in scope, covering the following subject areas: cosmic evolution of biogenic compounds; prebiotic evolution; early evolution of life; evolution of advanced life; solar system exploration; search for extraterrestrial intelligence; planetary protection; and advanced programs in biological systems research. A listing of the 1990 publications resulting from research supported by the Exobiology Program is presented.

14 CFR 170.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... approach control service. Arrival means any aircraft arriving at an airport. Benefit-cost ratio means the... (i.e., ATCT) divided by the discounted life cycle costs. Ceiling means the vertical distance between... to aviation users over the life span of a facility or service. Life cycle costs means the value of...

14 CFR 170.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... approach control service. Arrival means any aircraft arriving at an airport. Benefit-cost ratio means the... (i.e., ATCT) divided by the discounted life cycle costs. Ceiling means the vertical distance between... to aviation users over the life span of a facility or service. Life cycle costs means the value of...

14 CFR 170.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... approach control service. Arrival means any aircraft arriving at an airport. Benefit-cost ratio means the... (i.e., ATCT) divided by the discounted life cycle costs. Ceiling means the vertical distance between... to aviation users over the life span of a facility or service. Life cycle costs means the value of...

14 CFR 170.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... approach control service. Arrival means any aircraft arriving at an airport. Benefit-cost ratio means the... (i.e., ATCT) divided by the discounted life cycle costs. Ceiling means the vertical distance between... to aviation users over the life span of a facility or service. Life cycle costs means the value of...

The Balancing Act of Adult Life. ERIC Digest.

ERIC Educational Resources Information Center

Kerka, Sandra

Life is more complex than ever for adults in the 21st century as a result of technological advances; the changing nature of work, workplaces, and working relationships; international economic competition; the changing demographics of workers, families, and communities; and longer life spans. Learning to cope with all these changing…

Distribution of the anther-smut pathogen Microbotryum on species of the Caryophyllaceae

PubMed Central

Hood, Michael E; Mena-Alí, Jorge I; Gibson, Amanda K; Oxelman, Bengt; Giraud, Tatiana; Yockteng, Roxana; Arroyo, Mary T K; Conti, Fabio; Pedersen, Amy B; Gladieux, Pierre; Antonovics, Janis

2010-01-01

Summary Understanding disease distributions is of fundamental and applied importance, yet few studies benefit from integrating broad sampling with ecological and phylogenetic data. Here, anther-smut disease, caused by the fungus Microbotryum, was assessed using herbarium specimens of Silene and allied genera of the Caryophyllaceae.A total of 42 000 herbarium specimens were examined, and plant geographical distributions and morphological and life history characteristics were tested as correlates of disease occurrence. Phylogenetic comparative methods were used to determine the association between disease and plant life-span.Disease was found on 391 herbarium specimens from 114 species and all continents with native Silene. Anther smut occurred exclusively on perennial plants, consistent with the pathogen requiring living hosts to overwinter. The disease was estimated to occur in 80% of perennial species of Silene and allied genera. The correlation between plant life-span and disease was highly significant while controlling for the plant phylogeny, but the disease was not correlated with differences in floral morphology.Using resources available in natural history collections, this study illustrates how disease distribution can be determined, not by restriction to a clade of susceptible hosts or to a limited geographical region, but by association with host life-span, a trait that has undergone frequent evolutionary transitions. PMID:20406409

Thrombokinetics in patients with rheumatoid arthritis treated with D-penicillamine.

PubMed Central

Thomas, D; Gallus, A S; Brooks, P M; Tampi, R; Geddes, R; Hill, W

1984-01-01

The mechanism of D-penicillamine induced thrombocytopenia in rheumatoid arthritis was investigated by measuring platelet life-span and platelet production rate in 2 groups of rheumatoid arthritis patients treated with 250-750 mg/day D-penicillamine, 14 with a normal platelet count and 9 with thrombocytopenia (platelet count 50-130 X 10(9)/1). Age matched control patients not treated with D-penicillamine included 14 with rheumatoid arthritis and 9 with osteoarthritis. The platelet life-span was normal, but platelet production rate was significantly reduced in the thrombocytopenic patients, suggesting that D-penicillamine causes thrombocytopenia through bone marrow suppression. PMID:6742902

[Immunogenicity of L5178Y cells modified by different reagents].

PubMed

Gómez-Estrada, H; López-de la Rosa, L M; Becerril-Meza, G; Arellano-Blanco, J; Fernández-Quintero, P

1977-01-01

Lymphoma L5178Y cells were treated with neuraminidase of Vibrio cholerae, potassium iodine, dithiotreitol (DTT), mercaptoethanol, glutaraldehyde, iodoacetamide, merthiolate, sodium periodate, urea, papaine, trypsine and EDTA, to increase immunoreaction in tumor cells. Mice were immunized with modified tumor cells every week for one month. Thereafter non modified tumor cells were transplanted to previously immunized mice. Only the immunization with neuraminidase-treated cells rejected the tumor. Although the immunization with cells treated with potassium iodine, DTT and mercaptoethanol did not reject tumor, prolonged significantly span of life. The other reactives had neither effect on tumor rejection nor on span of life.

Hard-Earned Wisdom: Exploratory Processing of Difficult Life Experience Is Positively Associated with Wisdom

ERIC Educational Resources Information Center

Weststrate, Nic M.; Glück, Judith

2017-01-01

Laypersons and experts believe that wisdom is cultivated through a diverse range of positive and negative life experiences. Yet, not all individuals with life experience are wise. We propose that one possible determinant of growth in wisdom from life experience is self-reflection. In a life span sample of adults (N = 94) ranging from 26 to 92…

Life-History Traits and Population Structure of Pederson Cleaner Shrimps Ancylomenes pedersoni.

PubMed

Gilpin, Jessica A; Chadwick, Nanette E

2017-12-01

Cleaner organisms perform key functional roles in reducing rates of parasitism in marine communities. Pederson cleaner shrimps Ancylomenes pedersoni are major cleaners of reef fishes in the tropical western Atlantic and form obligate symbioses with host sea anemones. Information about their life-history traits would contribute to understanding how symbiosis impacts life-history evolution in crustaceans, but little is known about patterns of growth and reproduction in this anemone shrimp. We quantified growth, sexual reproduction, senescence, and mortality in individuals of A. pedersoni under laboratory conditions and their abundance and population size structure on coral reefs in St. Thomas, U.S. Virgin Islands. Von Bertalanffy growth curves were fitted to the data to determine age-size relationships, and the Beverton-Holt model was used to estimate mortality rates and size at maximum yield. Individuals grew rapidly when young, then slowed their growth after reaching sexual maturity at ~6 months. Individuals were gonochoric, with males attaining significantly smaller body sizes and shorter life spans than did females. Prior to death at <2 years, members of both genders exhibited senescence during which they ceased reproducing, shrank (females only), and decreased their activity levels over ~1-4 weeks. Field populations were abundant and composed mostly of juveniles during both years examined. Populations appeared to be stable but highly dynamic in terms of individuals, reaching maximum yield at 4 months of age. We conclude that obligate symbiosis with large sea anemones and cleaner mutualism with reef fishes both contribute to explaining aspects of the life history of Pederson shrimps, especially their apparent mating system of pure-search polygynandry. This life-history information also provides a scientific basis for sustainable fishery management and aquaculture of this key coral reef organism.

Origins and Evolution of Life

NASA Astrophysics Data System (ADS)

Gargaud, Muriel; López-García, Purificación; Martin, Hervé

2011-01-01

Part I. What Is Life?: 1. Problems raised by a definition of life M. Morange; 2. Some remarks about uses of cosmological anthropic 'principles' D. Lambert; 3. Minimal cell: the biologist point of view C. Brochier-Armanet; 4. Minimal cell: the computer scientist point of view H. Bersini; 5. Origins of life: computing and simulation approaches B. Billoud; Part II. Astronomical and Geophysical Context of the Emergence of Life: 6. Organic molecules in interstellar medium C. Ceccarelli and C. Cernicharo; 7. Cosmochemical evolution and the origin of life: insights from meteorites S. Pizzarello; 8. Astronomical constraints on the emergence of life M. Gounelle and T. Montmerle; 9. Formation of habitable planets J. Chambers; 10. The concept of galactic habitable zone N. Prantzos; 11. The young Sun and its influence on planetary atmospheres M. Güdel and J. Kasting; 12. Climates of the Earth G. Ramstein; Part III. Role of Water in the Emergence of Life: 13. Liquid water: a necessary condition to all forms of life K. Bartik, G. Bruylants, E. Locci and J. Reisse; 14. The role of water in the formation and evolution of planets T. Encrenaz; 15. Water on Mars J. P. Bibring; Part IV. From Non-Living Systems to Life: 16. Energetic constraints on prebiotic pathways: application to the emergence of translation R. Pascal and L. Boiteau; 17. Comparative genomics and early cell evolution A. Lazcano; 18. Origin and evolution of metabolisms J. Peretó; Part V. Mechanisms for Life Evolution: 19. Molecular phylogeny: inferring the patterns of evolution E. Douzery; 20. Horizontal gene transfer: mechanisms and evolutionary consequences D. Moreira; 21. The role of symbiosis in eukaryotic evolution A. Latorre, A. Durbán, A. Moya and J. Peretó; Part VI. Life in Extreme Conditions: 22. Life in extreme conditions: Deinococcus radiodurans, an organism able to survive prolonged desiccation and high doses of ionising radiation S. Sommer and M. Toueille; 23. Molecular effects of UV and ionizing radiations on DNA J. Cadet and T. Douki; 24. Molecular adaptations to life at high salt: lessons from Haloarcula marismortui G. Zaccai; Part VII. Traces of Life and Biosignatures: 25. Early life: nature, distribution and evolution F. Westall; 26. Early eukaryotes in precambrian oceans E. Javaux; 27. Biomineralisation mechanisms K. Benzerara and J. Miot; 28. Limits of life and biosphere: lesson from detection of microorganisms in deep sea and deep subsurface in the Earth K. Takai; Part VIII. Life Elsewhere?: 29. Titan and the Cassini-Huygens mission J. Lunine and F. Raulin; 30. The role of terrestrial analogue environments in astrobiology R. Léveillé; Index.

Publications of the exobiology program for 1981: A special bibliography

NASA Technical Reports Server (NTRS)

Pleasant, L. G. (Compiler); Devincenzi, D. L. (Compiler)

1982-01-01

The exobiology program investigates the planetary events which were responsible for, or, related to, the origin, evolution, and distribution of life in the universe. The areas involved include: chemical evolution, organic geochemistry, origin and evolution of life, planetary environments, life in the universe, planetary protection, and Mars data analysis.

Animal models of aging research: implications for human aging and age-related diseases.

PubMed

Mitchell, Sarah J; Scheibye-Knudsen, Morten; Longo, Dan L; de Cabo, Rafael

2015-01-01

Aging is characterized by an increasing morbidity and functional decline that eventually results in the death of an organism. Aging is the largest risk factor for numerous human diseases, and understanding the aging process may thereby facilitate the development of new treatments for age-associated diseases. The use of humans in aging research is complicated by many factors, including ethical issues; environmental and social factors; and perhaps most importantly, their long natural life span. Although cellular models of human disease provide valuable mechanistic information, they are limited in that they may not replicate the in vivo biology. Almost all organisms age, and thus animal models can be useful for studying aging. Herein, we review some of the major models currently used in aging research and discuss their benefits and pitfalls, including interventions known to extend life span and health span. Finally, we conclude by discussing the future of animal models in aging research.

Royal Jelly-Mediated Prolongevity and Stress Resistance in Caenorhabditis elegans Is Possibly Modulated by the Interplays of DAF-16, SIR-2.1, HCF-1, and 14-3-3 Proteins.

PubMed

Wang, Xiaoxia; Cook, Lauren F; Grasso, Lindsay M; Cao, Min; Dong, Yuqing

2015-07-01

Recent studies suggest that royal jelly (RJ) and its related substances may have antiaging properties. However, the molecular mechanisms underlying the beneficial effects remain elusive. We report that the effects of RJ and enzyme-treated RJ (eRJ) on life span and health span in Caenorhabditis elegans (C elegans) are modulated by the sophisticated interplays of DAF-16, SIR-2.1, HCF-1, and 14-3-3 proteins. Dietary supplementation with RJ or eRJ increased C. elegans life span in a dose-dependent manner. The RJ and eRJ consumption increased the tolerance of C elegans to oxidative stress, ultraviolet irradiation, and heat shock stress. Our genetic analyses showed that RJ/eRJ-mediated life-span extension requires insulin/IGF-1 signaling and the activities of DAF-16, SIR-2.1, HCF-1, and FTT-2, a 14-3-3 protein. Earlier studies reported that DAF-16/FOXO, SIR-2.1/SIRT1, FTT-2, and HCF-1 have extensive interplays in worms and mammals. Our present findings suggest that RJ/eRJ-mediated promotion of longevity and stress resistance in C elegans is dependent on these conserved interplays. From an evolutionary point of view, this study not only provides new insights into the molecular mechanisms of RJ's action on health span promotion in C elegans, but also has imperative implications in using RJ/eRJ as nutraceuticals to delay aging and age-related disorders. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

VIV analysis of pipelines under complex span conditions

NASA Astrophysics Data System (ADS)

Wang, James; Steven Wang, F.; Duan, Gang; Jukes, Paul

2009-06-01

Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections, but also generates vortex induced vibration (VIV), which can lead to fatigue issues. The phenomenon, if not predicted and controlled properly, will negatively affect pipeline integrity, leading to expensive remediation and intervention work. Span analysis can be complicated by: long span lengths, a large number of spans caused by a rough seabed, and multi-span interactions. In addition, the complexity can be more onerous and challenging when soil uncertainty, concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a ‘state-of-the-art’ finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.

An end to endless forms: epistasis, phenotype distribution bias, and nonuniform evolution.

PubMed

Borenstein, Elhanan; Krakauer, David C

2008-10-01

Studies of the evolution of development characterize the way in which gene regulatory dynamics during ontogeny constructs and channels phenotypic variation. These studies have identified a number of evolutionary regularities: (1) phenotypes occupy only a small subspace of possible phenotypes, (2) the influence of mutation is not uniform and is often canalized, and (3) a great deal of morphological variation evolved early in the history of multicellular life. An important implication of these studies is that diversity is largely the outcome of the evolution of gene regulation rather than the emergence of new, structural genes. Using a simple model that considers a generic property of developmental maps-the interaction between multiple genetic elements and the nonlinearity of gene interaction in shaping phenotypic traits-we are able to recover many of these empirical regularities. We show that visible phenotypes represent only a small fraction of possibilities. Epistasis ensures that phenotypes are highly clustered in morphospace and that the most frequent phenotypes are the most similar. We perform phylogenetic analyses on an evolving, developmental model and find that species become more alike through time, whereas higher-level grades have a tendency to diverge. Ancestral phenotypes, produced by early developmental programs with a low level of gene interaction, are found to span a significantly greater volume of the total phenotypic space than derived taxa. We suggest that early and late evolution have a different character that we classify into micro- and macroevolutionary configurations. These findings complement the view of development as a key component in the production of endless forms and highlight the crucial role of development in constraining biotic diversity and evolutionary trajectories.

Impact constraints on the environment for chemical evolution and the continuity of life

NASA Technical Reports Server (NTRS)

Oberbeck, Verne R.; Fogleman, Guy

1990-01-01

The moon and the earth were bombarded heavily by planetesimals and asteroids that were capable of interfering with chemical evolution and the origin of life. This paper explores the frequency of giant terrestrial impacts able to stop prebiotic chemistry in the probable regions of chemical evolution. The limited time available between impacts disruptive to prebiotic chemistry at the time of the oldest evidence of life suggests the need for a rapid process for chemical evolution of life. On the other hand, rapid chemical evolution in cloud systems and lakes or other shallow evaporating water bodies would have been possible because reactants could have been concentrated and polymerized rapidly in this environment. Thus life probably could have originated near the surface between frequent surface-sterilizing impacts. There may not have been continuity of life depending on sunlight because there is evidence that life, existing as early as 3.8 Gyr ago, may have been destroyed by giant impacts. The first such organisms on earth were probably not the ancestors of present life.

The Chandra X-Ray Observatory: Progress Report and Highlights

NASA Technical Reports Server (NTRS)

Weisskopf, Martin C.

2012-01-01

Over the past 13 years, the Chandra X-ray Observatory's ability to provide high resolution X-ray images and spectra have established it as one of the most versatile and powerful tools for astrophysical research in the 21st century. Chandra explores the hot, high-energy regions of the universe, observing X-ray sources with fluxes spanning more than 10 orders of magnitude, from the X-ray brightest, Sco X-1, to the faintest sources in the Chandra Deep Field South survey. Thanks to its continuing operational life, the Chandra mission now also provides a long observing baseline which, in and of itself, is opening new research opportunities. Observations in the past few years alone have deepened our understanding of the co-evolution of supermassive black holes and galaxies, the details of black hole accretion, the nature of dark energy and dark matter, the details of supernovae and their progenitors, the interiors of neutron stars, the evolution of massive stars, and the high-energy environment of protoplanetary nebulae and the interaction of an exo-planet with its star. Here we update the technical status, highlight some of the scientific results, and very briefly discuss future prospects. We fully expect that the Observatory will continue to provide outstanding scientific results for many years to come.

Life in the unthinking depths: energetic constraints on encephalization in marine fishes.

PubMed

Iglesias, T L; Dornburg, A; Brandley, M C; Alfaro, M E; Warren, D L

2015-05-01

Several hypotheses have been proposed to explain the limitation of brain size in vertebrates. Here, we test three hypotheses of brain size evolution using marine teleost fishes: the direct metabolic constraints hypothesis (DMCH), the expensive tissue hypothesis and the temperature-dependent hypothesis. Our analyses indicate that there is a robust positive correlation between encephalization and basal metabolic rate (BMR) that spans the full range of depths occupied by teleosts from the epipelagic (< 200 m), mesopelagic (200-1000 m) and bathypelagic (> 4000 m). Our results disentangle the effects of temperature and metabolic rate on teleost brain size evolution, supporting the DMCH. Our results agree with previous findings that teleost brain size decreases with depth; however, we also recover a negative correlation between trophic level and encephalization within the mesopelagic zone, a result that runs counter to the expectations of the expensive tissue hypothesis. We hypothesize that mesopelagic fishes at lower trophic levels may be investing more in neural tissue related to the detection of small prey items in a low-light environment. We recommend that comparative encephalization studies control for BMR in addition to controlling for body size and phylogeny. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Along the speciation continuum: Quantifying intrinsic and extrinsic isolating barriers across five million years of evolutionary divergence in California jewelflowers.

PubMed

Christie, Kyle; Strauss, Sharon Y

2018-05-01

Understanding the relative roles of intrinsic and extrinsic reproductive barriers, and their interplay within the geographic context of diverging taxa, remains an outstanding challenge in the study of speciation. We conducted a comparative analysis of reproductive isolation in California Jewelflowers (Streptanthus, s.l., Brassicaceae) by quantifying potential barriers to gene flow at multiple life history stages in 39 species pairs spanning five million years of evolutionary divergence. We quantified nine potential pre- and postzygotic barriers and explored patterns of reproductive isolation in relation to genetic distance. Intrinsic postzygotic isolation was initially weak, increased at intermediate genetic distances, and reached a threshold characterized by complete genetic incompatibility. Climatic niche differences were strong at shallow genetic distances, and species pairs with overlapping ranges showed slight but appreciable phenological isolation, highlighting the potential for ecological barriers to contribute to speciation. Geographic analyses suggest that speciation is not regionally allopatric in the California Jewelflowers, as recently diverged taxa occur in relatively close proximity and display substantial range overlap. Young pairs are characterized by incomplete intrinsic postzygotic isolation, suggesting that extrinsic barriers or fine-scale spatial segregation are more important early in the divergence process than genetic incompatibilities. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Gynecomastia Management: An Evolution and Refinement in Technique at UT Southwestern Medical Center

PubMed Central

Bailey, Steven H.; Guenther, Dax; Constantine, Fadi

2016-01-01

Summary: Gynecomastia is a benign proliferation of male breast glandular tissue. Gynecomastia can affect men at any stage of life. Traditional treatment options involved excisional surgeries with periareolar or T-shaped scars, which can leave more visible scars on the chest. The technique presented represents a technique used by the senior author, which relies on ultrasonic liposuction and pull-through technique to remove breast tissue. A retrospective chart review was performed, including all patients who were treated, from 2000 to 2013 by the senior author, for gynecomastia. A deidentified database was created to record patient characteristics, including age, height, weight, ptosis, stage of gynecomastia, and gynecomastia classification. Surgical approaches, complications, and revisions were also recorded. Our experience includes 75 patients with all grades of gynecomastia from 2000 to 2013. These cases span the evolution of our technique to include direct pull-through excision with ultrasound-assisted liposuction. The distribution of the grades I, II, III, and IV ptosis was 30.6%, 36 %, 22.6%, and 10.6% respectively. There were no complications in this series. Only one patient with grade III ptosis required revision surgery. This technique provides a safe and aesthetically pleasing way to treat gynecomastia with a low need for revision. PMID:27482482

Constraints on ocean carbonate chemistry and pCO2 in the Archaean and Palaeoproterozoic

NASA Astrophysics Data System (ADS)

Blättler, C. L.; Kump, L. R.; Fischer, W. W.; Paris, G.; Kasbohm, J. J.; Higgins, J. A.

2017-01-01

One of the great problems in the history of Earth’s climate is how to reconcile evidence for liquid water and habitable climates on early Earth with the Faint Young Sun predicted from stellar evolution models. Possible solutions include a wide range of atmospheric and oceanic chemistries, with large uncertainties in boundary conditions for the evolution and diversification of life and the role of the global carbon cycle in maintaining habitable climates. Increased atmospheric CO2 is a common component of many solutions, but its connection to the carbon chemistry of the ocean remains unknown. Here we present calcium isotope data spanning the period from 2.7 to 1.9 billion years ago from evaporitic sedimentary carbonates that can test this relationship. These data, from the Tumbiana Formation, the Campbellrand Platform and the Pethei Group, exhibit limited variability. Such limited variability occurs in marine environments with a high ratio of calcium to carbonate alkalinity. We are therefore able to rule out soda ocean conditions during this period of Earth history. We further interpret this and existing data to provide empirical constraints for carbonate chemistry of the ancient oceans and for the role of CO2 in compensating for the Faint Young Sun.

Comparative and functional characterization of intragenic tandem repeats in 10 Aspergillus genomes.

PubMed

Gibbons, John G; Rokas, Antonis

2009-03-01

Intragenic tandem repeats (ITRs) are consecutive repeats of three or more nucleotides found in coding regions. ITRs are the underlying cause of several human genetic diseases and have been associated with phenotypic variation, including pathogenesis, in several clades of the tree of life. We have examined the evolution and functional role of ITRs in 10 genomes spanning the fungal genus Aspergillus, a clade of relevance to medicine, agriculture, and industry. We identified several hundred ITRs in each of the species examined. ITR content varied extensively between species, with an average 79% of ITRs unique to a given species. For the fraction of conserved ITR regions, sequence comparisons within species and between close relatives revealed that they were highly variable. ITR-containing proteins were evolutionarily less conserved, compositionally distinct, and overrepresented for domains associated with cell-surface localization and function relative to the rest of the proteome. Furthermore, ITRs were preferentially found in proteins involved in transcription, cellular communication, and cell-type differentiation but were underrepresented in proteins involved in metabolism and energy. Importantly, although ITRs were evolutionarily labile, their functional associations appeared. To be remarkably conserved across eukaryotes. Fungal ITRs likely participate in a variety of developmental processes and cell-surface-associated functions, suggesting that their contribution to fungal lifestyle and evolution may be more general than previously assumed.

Reflecting on Language. (Reflexionando Sobre el Idioma.)

ERIC Educational Resources Information Center

Mazas, Jose Garcia

1980-01-01

Covering a 500-year span, this article traces the changes in and evolution of the Spanish language from its earliest written accounts in the eleventh century to the Spanish that was brought by the Conquistadores to the New World. (DS)

Lifespan extension by cranberry supplementation partially requires SOD2 and is life stage independent.

PubMed

Sun, Yaning; Yolitz, Jason; Alberico, Thomas; Sun, Xiaoping; Zou, Sige

2014-02-01

Many nutraceuticals and pharmaceuticals have been shown to promote healthspan and lifespan. However, the mechanisms underlying the beneficial effects of prolongevity interventions and the time points at which interventions should be implemented to achieve beneficial effects are not well characterized. We have previously shown that a cranberry-containing nutraceutical can promote lifespan in worms and flies and delay age-related functional decline of pancreatic cells in rats. Here we investigated the mechanism underlying lifespan extension induced by cranberry and the effects of short-term or life stage-specific interventions with cranberry on lifespan in Drosophila. We found that lifespan extension induced by cranberry was associated with reduced phosphorylation of ERK, a component of oxidative stress response MAPK signaling, and slightly increased phosphorylation of AKT, a component of insulin-like signaling. Lifespan extension was also associated with a reduced level of 4-hydroxynonenal protein adducts, a biomarker of lipid oxidation. Moreover, lifespan extension induced by cranberry was partially suppressed by knockdown of SOD2, a major mitochondrial superoxide scavenger. Furthermore, cranberry supplementation was administered in three life stages of adult flies, health span (3-30 days), transition span (31-60 days) and senescence span (61 days to the end when all flies died). Cranberry supplementation during any of these life stages extended the remaining lifespan relative to the non-supplemented and life stage-matched controls. These findings suggest that cranberry supplementation is sufficient to promote longevity when implemented during any life stage, likely through reducing oxidative damage. Published by Elsevier Inc.

Life-Span Exposure to Low Doses of Aspartame Beginning during Prenatal Life Increases Cancer Effects in Rats

PubMed Central

Soffritti, Morando; Belpoggi, Fiorella; Tibaldi, Eva; Esposti, Davide Degli; Lauriola, Michelina

2007-01-01

Background In a previous study conducted at the Cesare Maltoni Cancer Research Center of the European Ramazzini Foundation (CMCRC/ERF), we demonstrated for the first time that aspartame (APM) is a multipotent carcinogenic agent when various doses are administered with feed to Sprague-Dawley rats from 8 weeks of age throughout the life span. Objective The aim of this second study is to better quantify the carcinogenic risk of APM, beginning treatment during fetal life. Methods We studied groups of 70–95 male and female Sprague-Dawley rats administered APM (2,000, 400, or 0 ppm) with feed from the 12th day of fetal life until natural death. Results Our results show a) a significant dose-related increase of malignant tumor–bearing animals in males (p < 0.01), particularly in the group treated with 2,000 ppm APM (p < 0.01); b) a significant increase in incidence of lymphomas/leukemias in males treated with 2,000 ppm (p < 0.05) and a significant dose-related increase in incidence of lymphomas/leukemias in females (p < 0.01), particularly in the 2,000-ppm group (p < 0.01); and c) a significant dose-related increase in incidence of mammary cancer in females (p < 0.05), particularly in the 2,000-ppm group (p < 0.05). Conclusions The results of this carcinogenicity bioassay confirm and reinforce the first experimental demonstration of APM’s multipotential carcinogenicity at a dose level close to the acceptable daily intake for humans. Furthermore, the study demonstrates that when life-span exposure to APM begins during fetal life, its carcinogenic effects are increased. PMID:17805418

Developmental change in proactive interference across the life span: evidence from two working memory tasks.

PubMed

Loosli, Sandra V; Rahm, Benjamin; Unterrainer, Josef M; Weiller, Cornelius; Kaller, Christoph P

2014-04-01

Working memory (WM) as the ability to temporarily maintain and manipulate various kinds of information is known to be affected by proactive interference (PI) from previously relevant contents, but studies on developmental changes in the susceptibility to PI are scarce. In the present study, we investigated life span development of item-specific PI. To this end, 92 individuals between the ages of 8 and 74 years completed a recent-probes task and an n-back task that both composed experimental manipulations of PI. Regarding global WM development, young adults had higher WM performance than children and older adults in both tasks. Significant PI × Age interactions revealed that susceptibility to PI changed over the life span in both tasks, whereas the developmental course of PI differed between the tasks: Children committed more PI-related errors than young adults in the recent-probes task but showed marginally less PI in the n-back task. Regarding reaction time costs, children did not differ from adults in the recent-probes task and were less affected than adults in the n-back. Older adults showed more PI-related errors than young adults in both tasks. Therefore, as expected, item-specific PI changed over the life span with the young adults being less susceptible to PI than children and older adults. The diverging developmental effects of PI across both tasks, especially in the children, are supposed to reflect different causes for the difficulties regarding resisting PI in children and older adults. These might concern differently developed underlying cognitive processes such as inhibition or recollection, or different responses to task demands across both tasks. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Photosynthetic thermotolerance of woody savanna species in China is correlated with leaf life span

PubMed Central

Zhang, Jiao-Lin; Poorter, L.; Hao, Guang-You; Cao, Kun-Fang

2012-01-01

Background and Aims Photosynthetic thermotolerance (PT) is important for plant survival in tropical and sub-tropical savannas. However, little is known about thermotolerance of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Longer-lived leaves of savanna plants may experience a higher risk of heat stress. Foliar Ca is related to cell integrity of leaves under stresses. In this study it is hypothesized that (1) species with leaf flushing in the hot-dry season have greater PT than those with leaf flushing in the rainy season; and (2) PT correlates positively with leaf life span, leaf mass per unit area (LMA) and foliar Ca concentration ([Ca]) across woody savanna species. Methods The temperature-dependent increase in minimum fluorescence was measured to assess PT, together with leaf dynamics, LMA and [Ca] for a total of 24 woody species differing in leaf flushing time in a valley-type savanna in south-west China. Key Results The PT of the woody savanna species with leaf flushing in the hot-dry season was greater than that of those with leaf flushing in the rainy season. Thermotolerance was positively associated with leaf life span and [Ca] for all species irrespective of the time of flushing. The associations of PT with leaf life span and [Ca] were evolutionarily correlated. Thermotolerance was, however, independent of LMA. Conclusions Chinese savanna woody species are adapted to hot-dry habitats. However, the current maximum leaf temperature during extreme heat stress (44·3 °C) is close to the critical temperature of photosystem II (45·2 °C); future global warming may increase the risk of heat damage to the photosynthetic apparatus of Chinese savanna species. PMID:22875810

Hour Glass Half-Full or Half-Empty? Future Time Perspective and Preoccupation with Negative Events Across the Life Span

PubMed Central

Strough, JoNell; de Bruin, Wändi Bruine; Parker, Andrew M.; Lemaster, Philip; Pichayayothin, Nipat; Delaney, Rebecca

2016-01-01

According to socioemotional selectivity theory, older adults' emotional well-being stems from having limited future time perspective that motivates them to maximize well-being in the “here and now.” Presumably, then, older adults' time horizons are associated with emotional competencies that boost positive affect and dampen negative affect, but little research has addressed this. Using a US national adult life-span sample (N= 3,933, 18-93 yrs), we found that a two-factor model of future time perspective (focus on future opportunities; focus on limited time) fit the data better than a one-factor model. Through middle age, people perceived the life-span hourglass as half full—they focused more on future opportunities than limited time. Around age 60, the balance changed to increasingly perceiving the life-span hourglass as half empty—they focused less on future opportunities and more on limited time. This pattern held even after accounting for perceived health, self-reported decision-making ability, and retirement status. At all ages, women's time horizons focused more on future opportunities compared to men's, and men's focused more on limited time. Focusing on future opportunities was associated with reporting less preoccupation with negative events, whereas focusing on limited time was associated with reporting more preoccupation. Older adults reported less preoccupation with negative events and this association was stronger after controlling for their perceptions of limited time and fewer future opportunities, suggesting that other pathways may explain older adults' reports of their ability to disengage from negative events. Insights gained and questions raised by measuring future time perspective as two dimensions are discussed. PMID:27267222

Late-onset temperature reduction can retard the aging process in aged fish via a combined action of an anti-oxidant system and the insulin/insulin-like growth factor 1 signaling pathway.

PubMed

Wang, Xia; Chang, Qingyun; Wang, Yu; Su, Feng; Zhang, Shicui

2014-12-01

Two different mechanisms are considered to be related to aging. Cumulative molecular damage caused by reactive oxygen species (ROS), the by-products of oxidative phosphorylation, is one of these mechanisms (ROS concept). Deregulated nutrient sensing by the insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) pathway is the second mechanism (IIS concept). Temperature reduction (TR) is known to modulate aging and prolong life span in a variety of organisms, but the mechanisms remain poorly defined. Here we first demonstrate that late-onset TR from 26 °C to 22 °C extends mean life span and maximum life span by approximately 5.2 and 3 weeks, respectively, in the annual fish Nothobranchius guentheri. We then show that TR is able to decrease the accumulation of the histological aging markers senescence-associated β-galactosidase (SA-β-Gal) in the epithelium and lipofuscin (LF) in the liver and to reduce protein oxidation and lipid peroxidation levels in the muscle. We also show that TR can enhance the activities of catalase, glutathione peroxidase, and superoxide dismutase, and stimulate the synthesis of SirT1 and FOXO3A/FOXO1A, both of which are the downstream regulators of the IIS pathway. Taken together, our findings suggest that late-onset TR, a simple non-intrusion intervention, can retard the aging process in aged fish, resulting in their life span extension, via a synergistic action of an anti-oxidant system and the IIS pathway. This also suggests that combined assessment of the ROS and IIS concepts will contribute to providing a more comprehensive view of the anti-aging process.

eRapa Restores A Normal Life Span in a FAP Mouse Model

PubMed Central

Hasty, Paul; Livi, Carolina B.; Dodds, Sherry G.; Jones, Diane; Strong, Randy; Javors, Martin; Fischer, Kathleen E.; Sloane, Lauren; Murthy, Kruthi; Hubbard, Gene; Sun, Lishi; Hurez, Vincent; Curiel, Tyler J.; Sharp, Zelton Dave

2014-01-01

Mutation of a single copy of the adenomatous polyposis coli (APC) gene results in familial adenomatous polyposis (FAP), which confers an extremely high risk for colon cancer. ApcMin/+ mice exhibit multiple intestinal neoplasia (MIN) that causes anemia and death from bleeding by 6 months. Mechanistic target of rapamycin complex 1 (mTORC1) inhibitors were shown to improve ApcMin/+ mouse survival when administered by oral gavage or added directly to the chow, but these mice still died from neoplasia well short of a natural life span. The National Institute of Aging Intervention Testing Program showed that enterically targeted rapamycin (eRapa) extended life span for wild type genetically heterogeneous mice in part by inhibiting age-associated cancer. We hypothesized that eRapa would be effective in preventing neoplasia and extend survival of ApcMin/+ mice. We show that eRapa improved survival for ApcMin/+ mice in a dose-dependent manner. Remarkably, and in contrast to previous reports, most of the ApcMin/+ mice fed 42 ppm eRapa lived beyond the median life span reported for wild type syngeneic mice. Furthermore, chronic eRapa did not cause detrimental immune effects in mouse models of cancer, infection or autoimmunity; thus, assuaging concerns that chronic rapamycin treatment suppresses immunity. Our studies suggest that a novel formulation (enteric targeting) of a well-known and widely used drug (rapamycin) can dramatically improve its efficacy in targeted settings. eRapa or other mTORC1 inhibitors could serve as effective cancer preventatives for people with FAP without suppressing the immune system, thus reducing the dependency on surgery as standard therapy. PMID:24282255

Hour glass half full or half empty? Future time perspective and preoccupation with negative events across the life span.

PubMed

Strough, JoNell; Bruine de Bruin, Wändi; Parker, Andrew M; Lemaster, Philip; Pichayayothin, Nipat; Delaney, Rebecca

2016-09-01

According to socioemotional selectivity theory, older adults' emotional well-being stems from having a limited future time perspective that motivates them to maximize well-being in the "here and now." Presumably, then, older adults' time horizons are associated with emotional competencies that boost positive affect and dampen negative affect, but little research has addressed this. Using a U.S. adult life-span sample (N = 3,933; 18-93 years), we found that a 2-factor model of future time perspective (future opportunities; limited time) fit the data better than a 1-factor model. Through middle age, people perceived the life-span hourglass as half full-they focused more on future opportunities than limited time. Around Age 60, the balance changed to increasingly perceiving the life-span hourglass as half empty-they focused less on future opportunities and more on limited time, even after accounting for perceived health, self-reported decision-making ability, and retirement status. At all ages, women's time horizons focused more on future opportunities compared with men's, and men's focused more on limited time. Focusing on future opportunities was associated with reporting less preoccupation with negative events, whereas focusing on limited time was associated with reporting more preoccupation. Older adults reported less preoccupation with negative events, and this association was stronger after controlling for their perceptions of limited time and fewer future opportunities, suggesting that other pathways may explain older adults' reports of their ability to disengage from negative events. Insights gained and questions raised by measuring future time perspective as 2 dimensions are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Cardiac risk assessment: when and who? [Retrospectroscope].

PubMed

Valentinuzzi, M E; Arini, P D; Laciar, E; Bonomini, M P; Correa, R O

2013-07-01

Think about the above lines taken from the Old Testament: At 130 years of age, Adam begat a son and at 800 he kept going, quitting this earthly life at 930. These numbers surpass by far the limits our current experience teaches us, however, perhaps a life span into the hundreds of years is ? What if, in the future, science were to do away with disease? What then would cause people to die: accidents, killings, wars? How old would old age be? Aging has always been a hot topic for research (with considerable quackery, too). For example, animals with a slow metabolism tend to live longer than those with a fast metabolism. Compare the average life span of a mouse with that of a turtle. Apparently, meditators are able to slow their metabolism down [1].

What Teachers Should Know about the Evolution-Intentional Design Debate on the Origin of Life.

ERIC Educational Resources Information Center

Brekke, Stewart E.

This paper discusses the beginning of life on Earth, the formation of life forms, evolution, and the origin of life. The paper suggests that how life first appeared on earth is not known and may never be known. (YDS)

Longevity of clonal plants: why it matters and how to measure it

PubMed Central

de Witte, Lucienne C.; Stöcklin, Jürg

2010-01-01

Background Species' life-history and population dynamics are strongly shaped by the longevity of individuals, but life span is one of the least accessible demographic traits, particularly in clonal plants. Continuous vegetative reproduction of genets enables persistence despite low or no sexual reproduction, affecting genet turnover rates and population stability. Therefore, the longevity of clonal plants is of considerable biological interest, but remains relatively poorly known. Scope Here, we critically review the present knowledge on the longevity of clonal plants and discuss its importance for population persistence. Direct life-span measurements such as growth-ring analysis in woody plants are relatively easy to take, although, for many clonal plants, these methods are not adequate due to the variable growth pattern of ramets and difficult genet identification. Recently, indirect methods have been introduced in which genet size and annual shoot increments are used to estimate genet age. These methods, often based on molecular techniques, allow the investigation of genet size and age structure of whole populations, a crucial issue for understanding their viability and persistence. However, indirect estimates of clonal longevity are impeded because the process of ageing in clonal plants is still poorly understood and because their size and age are not always well correlated. Alternative estimators for genet life span such as somatic mutations have recently been suggested. Conclusions Empirical knowledge on the longevity of clonal species has increased considerably in the last few years. Maximum age estimates are an indicator of population persistence, but are not sufficient to evaluate turnover rates and the ability of long-lived clonal plants to enhance community stability and ecosystem resilience. In order to understand the dynamics of populations it will be necessary to measure genet size and age structure, not only life spans of single individuals, and to use such data for modelling of genet dynamics. PMID:20880935

Stress responses, vitagenes and hormesis as critical determinants in aging and longevity: Mitochondria as a "chi".

PubMed

Cornelius, Carolin; Perrotta, Rosario; Graziano, Antonio; Calabrese, Edward J; Calabrese, Vittorio

2013-04-25

Understanding mechanisms of aging and determinants of life span will help to reduce age-related morbidity and facilitate healthy aging. Average lifespan has increased over the last centuries, as a consequence of medical and environmental factors, but maximal life span remains unchanged. Extension of maximal life span is currently possible in animal models with measures such as genetic manipulations and caloric restriction (CR). CR appears to prolong life by reducing reactive oxygen species (ROS)-mediated oxidative damage. But ROS formation, which is positively implicated in cellular stress response mechanisms, is a highly regulated process controlled by a complex network of intracellular signaling pathways. By sensing the intracellular nutrient and energy status, the functional state of mitochondria, and the concentration of ROS produced in mitochondria, the longevity network regulates life span across species by coordinating information flow along its convergent, divergent and multiply branched signaling pathways, including vitagenes which are genes involved in preserving cellular homeostasis during stressful conditions. Vitagenes encode for heat shock proteins (Hsp) Hsp32, Hsp70, the thioredoxin and the sirtuin protein systems. Dietary antioxidants, have recently been demonstrated to be neuroprotective through the activation of hormetic pathways, including vitagenes. The hormetic dose-response, challenges long-standing beliefs about the nature of the dose-response in a lowdose zone, having the potential to affect significantly the design of pre-clinical studies and clinical trials as well as strategies for optimal patient dosing in the treatment of numerous diseases. Given the broad cytoprotective properties of the heat shock response there is now strong interest in discovering and developing pharmacological agents capable of inducing stress responses. Here we focus on possible signaling mechanisms involved in the activation of vitagenes resulting in enhanced defense against energy and stress resistance homeostasis dysiruption with consequent impact on longevity processes.

Ageless and Timeless: Perspectives on Giftedness across the Life Span

ERIC Educational Resources Information Center

Fiedler, Ellen D.

2016-01-01

Annemarie Roeper's timeless perspectives were demonstrated throughout her long and productive life. Her prolific writings and speeches continue to influence our understanding of giftedness at all ages and stages of life, and the time I spent with her had a profound and meaningful effect on my work. Annemarie incorporated her inner view of…

"Play" across the Life Cycle: From Initiative to Integrity to Transcendence

ERIC Educational Resources Information Center

Jones, Elizabeth

2011-01-01

In this autobiographical journey through life-span developmental theory, the author reflects on her life as a player, embedding it in the context of Erik Erikson and Joan Erikson's stages of human development. The author builds on these basic ideas--theory, storytelling, play, and development--and defines them as simply as possible.

Preparation for Old Age in Different Life Domains: Dimensions and Age Differences

ERIC Educational Resources Information Center

Kornadt, Anna E.; Rothermund, Klaus

2014-01-01

We investigated preparation for age-related changes from a multidimensional, life span perspective and administered a newly developed questionnaire to a large sample aged 30-80 years. Preparing for age-related changes was organized by life domains, with domain-specific types of preparation addressing obstacles and opportunities in the respective…

Life stage dependent responses to desiccation risk in the annual killifish Nothobranchius wattersi.

PubMed

Grégoir, A F; Philippe, C; Pinceel, T; Reniers, J; Thoré, E S J; Vanschoenwinkel, B; Brendonck, L

2017-09-01

To assess whether the annual killifish Nothobranchius wattersi responds plastically to a desiccation risk and whether this response is life stage dependent, life-history traits such as maturation time, fecundity and life span were experimentally measured in N. wattersi that were subjected to a drop in water level either as juveniles, as adults or both as juveniles and adults. Fish that were exposed to simulated pool drying as juveniles did not show changes in reproductive output or life span. Adults reacted by doubling short term egg deposition at the cost of a shorter lifespan. Overall, these results suggest that annual fish species can use phenotypic plasticity to maximize their reproductive output when faced with early pond drying, but this response appears to be life-stage specific. In addition to frogs and aquatic insects, phenotypic plasticity induced by forthcoming drought is now also confirmed in annual fishes and could well be a common feature of the limited number of fish taxa that manage to survive in this extreme environment. © 2017 The Fisheries Society of the British Isles.

Using machine learning to explore the long-term evolution of GRS 1915+105

NASA Astrophysics Data System (ADS)

Huppenkothen, Daniela; Heil, Lucy M.; Hogg, David W.; Mueller, Andreas

2017-04-01

Among the population of known Galactic black hole X-ray binaries, GRS 1915+105 stands out in multiple ways. It has been in continuous outburst since 1992, and has shown a wide range of different states that can be distinguished by their timing and spectral properties. These states, also observed in IGR J17091-3624, have in the past been linked to accretion dynamics. Here, we present the first comprehensive study into the long-term evolution of GRS 1915+105, using the entire data set observed with Rossi X-ray Timing Explorer over its 16-yr lifetime. We develop a set of descriptive features allowing for automatic separation of states, and show that supervised machine learning in the form of logistic regression and random forests can be used to efficiently classify the entire data set. For the first time, we explore the duty cycle and time evolution of states over the entire 16-yr time span, and find that the temporal distribution of states has likely changed over the span of the observations. We connect the machine classification with physical interpretations of the phenomenology in terms of chaotic and stochastic processes.

Origin and evolution of life on terrestrial planets.

PubMed

Brack, A; Horneck, G; Cockell, C S; Bérces, A; Belisheva, N K; Eiroa, Carlos; Henning, Thomas; Herbst, Tom; Kaltenegger, Lisa; Léger, Alain; Liseau, Réne; Lammer, Helmut; Selsis, Franck; Beichman, Charles; Danchi, William; Fridlund, Malcolm; Lunine, Jonathan; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Röttgering, Huub; Schneider, Jean; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

2010-01-01

The ultimate goal of terrestrial planet-finding missions is not only to discover terrestrial exoplanets inside the habitable zone (HZ) of their host stars but also to address the major question as to whether life may have evolved on a habitable Earth-like exoplanet outside our Solar System. We note that the chemical evolution that finally led to the origin of life on Earth must be studied if we hope to understand the principles of how life might evolve on other terrestrial planets in the Universe. This is not just an anthropocentric point of view: the basic ingredients of terrestrial life, that is, reduced carbon-based molecules and liquid H(2)O, have very specific properties. We discuss the origin of life from the chemical evolution of its precursors to the earliest life-forms and the biological implications of the stellar radiation and energetic particle environments. Likewise, the study of the biological evolution that has generated the various life-forms on Earth provides clues toward the understanding of the interconnectedness of life with its environment.

Learning Evolution and the Nature of Science Using Evolutionary Computing and Artificial Life

ERIC Educational Resources Information Center

Pennock, Robert T.

2007-01-01

Because evolution in natural systems happens so slowly, it is difficult to design inquiry-based labs where students can experiment and observe evolution in the way they can when studying other phenomena. New research in evolutionary computation and artificial life provides a solution to this problem. This paper describes a new A-Life software…

Night life on the beach: selfing to avoid pollinator competition between two sympatric Silene species.

PubMed

Buide, M Luisa; del Valle, José Carlos; Pissatto, Mônica; Narbona, Eduardo

2015-08-01

Evolution of autonomous selfing may be advantageous because it allows for reproductive assurance. In co-flowering plants competing for pollinators, the least common and/or attractive could suffer pollen limitations. Silene niceensis and S. ramosissima are taxonomically related species sharing the same habitat, although S. ramosissima is less abundant and has a more restricted distribution. They also have the same a priori nocturnal pollinator syndrome, and show an overlapping flowering phenology. The aim of this study was to investigate whether a selfing strategy in S. ramosissima allows it to avoid pollinator competition and/or interspecific pollen transfer with S. niceensis, which would thus enable both species to reach high levels of fruit and seed set. The breeding system, petal colour, flower life span and degree of overlap between male and female phases, floral visitor abundance and visitation rates were analysed in two sympatric populations of S. niceensis and S. ramosissima in southern Spain. Autonomous selfing in S. ramosissima produced very high fruit and seed set, which was also similar to open-pollinated plants. Silene niceensis showed minimum levels of autonomous selfing, and pollen/ovule ratios were within the range expected for the breeding system. In contrast to S. niceensis, flower life span was much shorter in S. ramosissima, and male and female organs completely overlapped in space and time. Upper surface petals of both species showed differing brightness, chroma and hue. Flowers of S. niceensis were actively visited by moths, hawkmoths and syrphids, whereas those of S. ramosissima were almost never visited. The findings show that different breeding strategies exist between the sympatric co-flowering S. niceensis and S. ramosissima, the former specializing in crepuscular-nocturnal pollination and the latter mainly based on autonomous selfing. These two strategies allow both species to share the restricted dune habitat in which they exist, with a high female reproductive success due to the absence of pollinator competition and/or interspecific pollen flow. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Evolution of Design

ERIC Educational Resources Information Center

Stebbins, G. Ledyard

1973-01-01

Describes the basic logic behind the modern view of evolution theory. Despite gaps in fossil records, evidence is indicative of the origin of life from nonliving molecules and evolution of higher forms of life from simpler forms. (PS)

Magnetohydrodynamic thermochemotherapy and MRI of mouse tumors

NASA Astrophysics Data System (ADS)

Brusentsov, Nikolay A.; Brusentsova, Tatiana N.; Filinova, Elena Yu.; Jurchenko, Nikolay Y.; Kupriyanov, Dmitry A.; Pirogov, Yuri A.; Dubina, Andry I.; Shumskikh, Maxim N.; Shumakov, Leonid I.; Anashkina, Ekaterina N.; Shevelev, Alexandr A.; Uchevatkin, Andry A.

2007-04-01

A dextran-ferrite magnetic fluid was successfully tested as magnetic resonance imaging (MRI) contrast agent. The same magnetic fluid was then combined with Melphalan, a chemotherapeutic drug, and used for magnetohydrodynamic thermochemotherapy of different tumors. The placement of the tumors in an AC magnetic field led to hyperthermia at 46 °C for 30 min. In combination with tumor slime aspiration, a 30% regression of ˜130 mm 3 non-metastatic P388 tumors in BDF 1 mice was reached, together with a life span increase of 290%. The same procedure associated with cyclophosphamide treatment of ˜500 mm 3 metastases tumor increased the animal's life span by 180%.

An Integrated Socio-Environmental Model of Health and Well-Being: a Conceptual Framework Exploring the Joint Contribution of Environmental and Social Exposures to Health and Disease Over the Life Span.

PubMed

Olvera Alvarez, Hector A; Appleton, Allison A; Fuller, Christina H; Belcourt, Annie; Kubzansky, Laura D

2018-06-01

Environmental and social determinants of health often co-occur, particularly among socially disadvantaged populations, yet because they are usually studied separately, their joint effects on health are likely underestimated. Building on converging bodies of literature, we delineate a conceptual framework to address these issues. Previous models provided a foundation for study in this area, and generated research pointing to additional important issues. These include a stronger focus on biobehavioral pathways, both positive and adverse health outcomes, and intergenerational effects. To accommodate the expanded set of issues, we put forward the Integrated Socio-Environmental Model of Health and Well-Being (ISEM), which examines how social and environmental factors combine and potentially interact, via multi-factorial pathways, to affect health and well-being over the life span. We then provide applied examples including the study of how food environments affect dietary behavior. The ISEM provides a comprehensive, theoretically informed framework to guide future research on the joint contribution of social and environmental factors to health and well-being across the life span.

Time scale matters: genetic analysis does not support adaptation-by-time as the mechanism for adaptive seasonal declines in kokanee reproductive life span

PubMed Central

Morbey, Yolanda E; Jensen, Evelyn L; Russello, Michael A

2014-01-01

Seasonal declines of fitness-related traits are often attributed to environmental effects or individual-level decisions about reproductive timing and effort, but genetic variation may also play a role. In populations of Pacific salmon (Oncorhynchus spp.), seasonal declines in reproductive life span have been attributed to adaptation-by-time, in which divergent selection for different traits occurs among reproductively isolated temporal components of a population. We evaluated this hypothesis in kokanee (freshwater obligate Oncorhynchus nerka) by testing for temporal genetic structure in neutral and circadian-linked loci. We detected no genetic differences in presumably neutral loci among kokanee with different arrival and maturation dates within a spawning season. Similarly, we detected no temporal genetic structure in OtsClock1b, Omy1009uw, or OmyFbxw11, candidate loci associated with circadian function. The genetic evidence from this study and others indicates a lack of support for adaptation-by-time as an important evolutionary mechanism underlying seasonal declines in reproductive life span and a need for greater consideration of other mechanisms such as time-dependent, adaptive adjustment of reproductive effort. PMID:25478160

Lifespan development of pro- and anti-saccades: multiple regression models for point estimates.

PubMed

Klein, Christoph; Foerster, Friedrich; Hartnegg, Klaus; Fischer, Burkhart

2005-12-07

The comparative study of anti- and pro-saccade task performance contributes to our functional understanding of the frontal lobes, their alterations in psychiatric or neurological populations, and their changes during the life span. In the present study, we apply regression analysis to model life span developmental effects on various pro- and anti-saccade task parameters, using data of a non-representative sample of 327 participants aged 9 to 88 years. Development up to the age of about 27 years was dominated by curvilinear rather than linear effects of age. Furthermore, the largest developmental differences were found for intra-subject variability measures and the anti-saccade task parameters. Ageing, by contrast, had the shape of a global linear decline of the investigated saccade functions, lacking the differential effects of age observed during development. While these results do support the assumption that frontal lobe functions can be distinguished from other functions by their strong and protracted development, they do not confirm the assumption of disproportionate deterioration of frontal lobe functions with ageing. We finally show that the regression models applied here to quantify life span developmental effects can also be used for individual predictions in applied research contexts or clinical practice.

A mitochondrial mutator plasmid that causes senescence under dietary restricted conditions

PubMed Central

Maas, Marc FPM; Hoekstra, Rolf F; Debets, Alfons JM

2007-01-01

Background Calorie or dietary restriction extends life span in a wide range of organisms including the filamentous fungus Podospora anserina. Under dietary restricted conditions, P. anserina isolates are several-fold longer lived. This is however not the case in isolates that carry one of the pAL2-1 homologous mitochondrial plasmids. Results We show that the pAL2-1 homologues act as 'insertional mutators' of the mitochondrial genome, which may explain their negative effect on life span extension. Sequencing revealed at least fourteen unique plasmid integration sites, of which twelve were located within the mitochondrial genome and two within copies of the plasmid itself. The plasmids were able to integrate in their entirety, via a non-homologous mode of recombination. Some of the integrated plasmid copies were truncated, which probably resulted from secondary, post-integrative, recombination processes. Integration sites were predominantly located within and surrounding the region containing the mitochondrial rDNA loci. Conclusion We propose a model for the mechanism of integration, based on innate modes of mtDNA recombination, and discuss its possible link with the plasmid's negative effect on dietary restriction mediated life span extension. PMID:17407571

Stochastic variation in telomere shortening rate causes heterogeneity of human fibroblast replicative life span.

PubMed

Martin-Ruiz, Carmen; Saretzki, Gabriele; Petrie, Joanne; Ladhoff, Juliane; Jeyapalan, Jessie; Wei, Wenyi; Sedivy, John; von Zglinicki, Thomas

2004-04-23

The replicative life span of human fibroblasts is heterogeneous, with a fraction of cells senescing at every population doubling. To find out whether this heterogeneity is due to premature senescence, i.e. driven by a nontelomeric mechanism, fibroblasts with a senescent phenotype were isolated from growing cultures and clones by flow cytometry. These senescent cells had shorter telomeres than their cycling counterparts at all population doubling levels and both in mass cultures and in individual subclones, indicating heterogeneity in the rate of telomere shortening. Ectopic expression of telomerase stabilized telomere length in the majority of cells and rescued them from early senescence, suggesting a causal role of telomere shortening. Under standard cell culture conditions, there was a minor fraction of cells that showed a senescent phenotype and short telomeres despite active telomerase. This fraction increased under chronic mild oxidative stress, which is known to accelerate telomere shortening. It is possible that even high telomerase activity cannot fully compensate for telomere shortening in all cells. The data show that heterogeneity of the human fibroblast replicative life span can be caused by significant stochastic cell-to-cell variation in telomere shortening.

Dissociable Changes of Frontal and Parietal Cortices in Inherent Functional Flexibility across the Human Life Span.

PubMed

Yin, Dazhi; Liu, Wenjing; Zeljic, Kristina; Wang, Zhiwei; Lv, Qian; Fan, Mingxia; Cheng, Wenhong; Wang, Zheng

2016-09-28

Extensive evidence suggests that frontoparietal regions can dynamically update their pattern of functional connectivity, supporting cognitive control and adaptive implementation of task demands. However, it is largely unknown whether this flexibly functional reconfiguration is intrinsic and occurs even in the absence of overt tasks. Based on recent advances in dynamics of resting-state functional resonance imaging (fMRI), we propose a probabilistic framework in which dynamic reconfiguration of intrinsic functional connectivity between each brain region and others can be represented as a probability distribution. A complexity measurement (i.e., entropy) was used to quantify functional flexibility, which characterizes heterogeneous connectivity between a particular region and others over time. Following this framework, we identified both functionally flexible and specialized regions over the human life span (112 healthy subjects from 13 to 76 years old). Across brainwide regions, we found regions showing high flexibility mainly in the higher-order association cortex, such as the lateral prefrontal cortex (LPFC), lateral parietal cortex, and lateral temporal lobules. In contrast, visual, auditory, and sensory areas exhibited low flexibility. Furthermore, we observed that flexibility of the right LPFC improved during maturation and reduced due to normal aging, with the opposite occurring for the left lateral parietal cortex. Our findings reveal dissociable changes of frontal and parietal cortices over the life span in terms of inherent functional flexibility. This study not only provides a new framework to quantify the spatiotemporal behavior of spontaneous brain activity, but also sheds light on the organizational principle behind changes in brain function across the human life span. Recent neuroscientific research has demonstrated that the human capability of adaptive task control is primarily the result of the flexible operation of frontal brain networks. However, it remains unclear whether this flexibly functional reconfiguration is intrinsic and occurs in the absence of an overt task. In this study, we propose a probabilistic framework to quantify the functional flexibility of each brain region using resting-state fMRI. We identify regions showing high flexibility mainly in the higher-order association cortex. In contrast, primary and unimodal visual and sensory areas show low flexibility. On the other hand, our findings reveal dissociable changes of frontal and parietal cortices in terms of inherent functional flexibility over the life span. Copyright © 2016 the authors 0270-6474/16/3610060-15$15.00/0.

"A general benevolence dimension that links neural, psychological, economic, and life-span data on altruistic tendencies": Correction to Hubbard et al. (2016).

PubMed

2016-10-01

Reports an error in "A general benevolence dimension that links neural, psychological, economic, and life-span data on altruistic tendencies" by Jason Hubbard, William T. Harbaugh, Sanjay Srivastava, David Degras and Ulrich Mayr ( Journal of Experimental Psychology: General , Advanced Online Publication, Aug 11, 2016, np). In the article, there was an error in the Task, Stimuli, and Procedures section. In the 1st sentence in the 6th paragraph, “Following the scanning phase, participants completed self-report questionnaires meant to reflected the Prosocial Disposition construct: the agreeableness scale from the Big F, which includes empathic concern and perspective-taking, and a scale of personality descriptive adjectives related to altruistic behavior (Wood, Nye, & Saucier, 2010).” should have read: “Following the scanning phase, participants completed self-report questionnaires that contained scales to reflect the Prosocial Disposition construct: the Big Five Inventory (BFI; John et al., 1991), from which we used the agreeableness scale to measure prosocial disposition; the Interpersonal Reactivity Index (IRI; Davis, 1980), from which we used the empathic concern and perspective-taking scales; and a scale of personality descriptive adjectives related to altruistic behavior (Wood, Nye, & Saucier, 2010).” (The following abstract of the original article appeared in record 2016-39037-001.) Individual and life span differences in charitable giving are an important economic force, yet the underlying motives are not well understood. In an adult, life span sample, we assessed manifestations of prosocial tendencies across 3 different measurement domains: (a) psychological self-report measures, (b) actual giving choices, and (c) fMRI-derived, neural indicators of “pure altruism.” The latter expressed individuals’ activity in neural valuation areas when charities received money compared to when oneself received money and thus reflected an altruistic concern for others. Results based both on structural equation modeling and unit-weighted aggregate scores revealed a strong higher-order General Benevolence dimension that accounted for variability across all measurement domains. The fact that the neural measures likely reflect pure altruistic tendencies indicates that General Benevolence is based on a genuine concern for others. Furthermore, General Benevolence exhibited a robust increase across the adult life span, potentially providing an explanation for why older adults typically contribute more to the public good than young adults. PsycINFO Database Record (c) 2016 APA, all rights reserved

Meaning and Purpose in Life across the Life Span: A Cross-Sectional Multivariate Analysis.

ERIC Educational Resources Information Center

Reker, Gary T.; And Others

This paper explores the developmental changes in meaning and purpose across the life course. Thirty males and females at the developmental stages of young adulthood (16-29 years), early middle-age (30-49 years), late middle-age (50-64 years), young-old (65-74 years) and old-old (75+ years) completed the Reker and Peacock (1981) Life Attitude…

The Study of Life Review. An Approach to the Investigation of Intellectual Development across the Life Span. Studien und Berichte 47.

ERIC Educational Resources Information Center

Staudinger, Ursula M.

A study looked for age differences in the quality of responses to the Life Review Task (LRT), studied the LRT itself as a tool for exploring wisdom and intellectual functioning in adulthood, and considered personality characteristics and life experience as alternative predictors of response quality. Sixty-three West German women of different ages…

Life Satisfaction Shows Terminal Decline in Old Age: Longitudinal Evidence from the German Socio-Economic Panel Study (SOEP)

ERIC Educational Resources Information Center

Gerstorf, Denis; Ram, Nilam; Estabrook, Ryne; Schupp, Jurgen; Wagner, Gert G.; Lindenberger, Ulman

2008-01-01

Longitudinal data spanning 22 years, obtained from deceased participants of the German Socio-Economic Panel Study (SOEP; N = 1,637; 70- to 100-year-olds), were used to examine if and how life satisfaction exhibits terminal decline at the end of life. Changes in life satisfaction were more strongly associated with distance to death than with…

Evolution of dispersal in spatially and temporally variable environments: The importance of life cycles.

PubMed

Massol, François; Débarre, Florence

2015-07-01

Spatiotemporal variability of the environment is bound to affect the evolution of dispersal, and yet model predictions strongly differ on this particular effect. Recent studies on the evolution of local adaptation have shown that the life cycle chosen to model the selective effects of spatiotemporal variability of the environment is a critical factor determining evolutionary outcomes. Here, we investigate the effect of the order of events in the life cycle on the evolution of unconditional dispersal in a spatially heterogeneous, temporally varying landscape. Our results show that the occurrence of intermediate singular strategies and disruptive selection are conditioned by the temporal autocorrelation of the environment and by the life cycle. Life cycles with dispersal of adults versus dispersal of juveniles, local versus global density regulation, give radically different evolutionary outcomes that include selection for total philopatry, evolutionary bistability, selection for intermediate stable states, and evolutionary branching points. Our results highlight the importance of accounting for life-cycle specifics when predicting the effects of the environment on evolutionarily selected trait values, such as dispersal, as well as the need to check the robustness of model conclusions against modifications of the life cycle. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Antioxidant Capacity of “Mexican Arnica” Heterotheca inuloides Cass Natural Products and Some Derivatives: Their Anti-Inflammatory Evaluation and Effect on C. elegans Life Span

PubMed Central

Rodríguez-Chávez, José Luis; Nieto-Camacho, Antonio; Delgado-Lamas, Guillermo

2015-01-01

It has been suggested that the accumulation of biomolecular damage caused by reactive oxygen species (ROS) contributes to aging. The antioxidant activity is related to the ability of certain compounds to protect against the potentially harmful effect of processes or reactions involving ROS. This ability is associated with the termination of free radical propagation in biological systems. From Heterotheca inuloides various compounds which have shown to possess antioxidant capacity and scavenging ROS. The aim of this study was to determine the antioxidant capacity of additional natural components isolated from H. inuloides and some semisynthetic derivatives, their anti-inflammatory activity and the effect on Caenorhabditis elegans nematode life span. Compounds showed ability to inhibit various biological processes such as lipid peroxidation, scavenge nonbiological important oxidants such as 1O2, OH∙, H2O2, and HOCl and scavenge non biological stable free radicals (DPPH). Some cadinane type compounds showed possess antioxidant, ROS scavenging capacity, anti-inflammatory activity, and effect on the C. elegans life span. Flavonoid type compounds increased the life of the nematode and quercetin was identified as the compound with the greatest activity. The modification of chemical structure led to a change in the antioxidant capacity, the anti-inflammatory activity, and the survival of the worm. PMID:25821555

The mouse as a model organism in aging research: usefulness, pitfalls and possibilities.

PubMed

Vanhooren, Valerie; Libert, Claude

2013-01-01

The mouse has become the favorite mammalian model. Among the many reasons for this privileged position of mice is their genetic proximity to humans, the possibilities of genetically manipulating their genomes and the availability of many tools, mutants and inbred strains. Also in the field of aging, mice have become very robust and reliable research tools. Since laboratory mice have a life expectancy of only a few years, genetic approaches and other strategies for intervening in aging can be tested by examining their effects on life span and aging parameters during the relatively short period of, for example, a PhD project. Moreover, experiments on mice with an extended life span as well as on mice demonstrating signs of (segmental) premature aging, together with genetic mapping strategies, have provided novel insights into the fundamental processes that drive aging. Finally, the results of studies on caloric restriction and pharmacological anti-aging treatments in mice have a high degree of relevance to humans. In this paper, we review a number of recent genetic mapping studies that have yielded novel insights into the aging process. We discuss the value of the mouse as a model for testing interventions in aging, such as caloric restriction, and we critically discuss mouse strains with an extended or a shortened life span as models of aging. Copyright © 2012 Elsevier B.V. All rights reserved.

Give one species the task to come up with a theory that spans them all: what good can come out of that?

PubMed Central

2017-01-01

Does the progress in understanding evolutionary theory depend on the species that is doing the investigation? This question is difficult to answer scientifically, as we are dealing with an n = 1 scenario: every individual who has ever written about evolution is a human being. I will discuss, first, whether we get the correct answer to questions if we begin with ourselves and expand outwards, and second, whether we might fail to ask all the interesting questions unless we combat our tendencies to favour taxa that are close to us. As a whole, the human tendency to understand general biological phenomena via ‘putting oneself in another organism's shoes’ has upsides and downsides. As an upside, our intuitive ability to rethink strategies if the situation changes can lead to ready generation of adaptive hypotheses. Downsides occur if we trust this intuition too much, and particular danger zones exist for traits where humans are an unusual species. I argue that the levels of selection debate might have proceeded differently if human cooperation patterns were not so unique, as this brings about unique challenges in biology teaching; and that theoretical insights regarding inbreeding avoidance versus tolerance could have spread faster if we were not extrapolating our emotional reactions to incest disproportionately depending on whether we study animals or plants. I also discuss patterns such as taxonomic chauvinism, i.e. less attention being paid to species that differ more from human-like life histories. Textbooks on evolution reinforce such biases insofar as they present, as a default case, systems that resemble ours in terms of life cycles and other features (e.g. gonochorism). Additionally, societal norms may have led to incorrect null hypotheses such as females not mating multiply. PMID:29142112

Longevity and aging: role of genes and of the extracellular matrix.

PubMed

Robert, L; Labat-Robert, J

2015-02-01

Longevity is different for every animal species as well as their genome, suggesting a correlation between genes and life-span. Estimates put the genetic effect from 5 to 35% approximately, suggesting that even genetic effects are dependent on environmental conditions. This contention is largely confirmed by the study of identical twins raised apart. They do not die at the same age and also for different reasons. Aging is not "genetically programmed", it is outside evolutionary constraint. Evolution favors early and efficient reproduction, but does not care for longevity. A number of mechanisms were shown to be involved in the age-dependent decline of vital functions, among them the Maillard reaction (non-enzymatic glycosylation) and the age-dependent upregulation of proteolytic activity. Aging of ECM is a complex process, comprising progressive modification of its macromolecular components and of cell-matrix interactions. An important process is the uncoupling with age of the elastin-receptor from its "young" transmission pathway loosing all physiological effects, but enhancing free radical and elastase release. These processes contribute to age-related ECM degradation, production of matrikins (ECM degradation products with biological activity) aggravating functional loss with age. Both genetic and post-genetic mechanisms are susceptible to be influenced by medical, pharmacological and dietary interventions. Among the genetic mechanisms, those attributed to Sirtuins (7 orthologs identified in the human genome) are especially important. Among the environmental effects, nutrition, hygiene and weather conditions play a role. These data justify some predictions on the evolution of life expectancy taking in account also socio-economic factors. Biological constraints become evident by the comparison of centenarians and supercentenarians (less than 1% of the centenarians) putting an upper limit to the attainable human lifespan.

Morphological evolution of an ephemeral tidal inlet from opening to closure: The Albufeira inlet, Portugal

NASA Astrophysics Data System (ADS)

Fortunato, André B.; Nahon, Alphonse; Dodet, Guillaume; Rita Pires, Ana; Conceição Freitas, Maria; Bruneau, Nicolas; Azevedo, Alberto; Bertin, Xavier; Benevides, Pedro; Andrade, César; Oliveira, Anabela

2014-02-01

Like other similar coastal systems, the Albufeira lagoon is artificially opened every year to promote water renewal and closes naturally within a few months. The evolution of the Albufeira Lagoon Inlet from its opening in April 2010 to its closure 8 months later is qualitatively and quantitatively analyzed through a combination of monthly field surveys and the application of a process-based morphodynamic model. Field data alone would not cover the whole space-time domain of the morphology of the inlet during its life time, whereas the morphodynamic model alone cannot reliably simulate the morphological development. Using a nudging technique introduced herein, this problem is overcome and a reliable and complete data set is generated for describing the morphological development of the tidal inlet. The new technique is shown to be a good alternative to extensive model calibration, as it can drastically improve the model performance. Results reveal that the lagoon imported sediments during its life span. However, the whole system (lagoon plus littoral barrier) actually lost sediments to the sea. This behavior is partly attributed to the modulation of tidal asymmetry by the spring-neap cycle, which reduces flood dominance on spring tides. Results also allowed the assessment of the relationship between the spring tidal prism and the cross-section of tidal inlets (the PA relationship). While this relationship is well established from empirical, theoretical and numerical evidences, its validity in inlets that are small or away from equilibrium was unclear. Results for the Albufeira lagoon reveal an excellent match between the new data and the empirical PA relationship derived for larger inlets and equilibrium conditions, supporting the validity of the relationship beyond its original scope.

Exobiology: The NASA program

NASA Technical Reports Server (NTRS)

Rummel, John D.; Harper, Lynn; Andersen, Dale

1992-01-01

The goal of NASA's Exobiology Program is to understand the origin, evolution, and distribution of life in the universe. To do this, the Exobiology Program seeks to provide a critical framework and some key research to allow NASA to bear the combined talents and capabilities of the agency and the scientific community, and the unique opportunities afforded by space exploration. To provide structure and direction to the quest for answers, the Exobiology Program has instituted a comprehensive research program divided into four elements which are being implemented at several of NASA's research centers and in the university community. These program elements correspond to the four major epochs in the evolution of living systems: (1) cosmic evolution of the biogenic compounds; (2) prebiotic evolution; (3) origin and early evolution of life; and (4) evolution of advanced life. The overall research program is designed to trace the pathways leading from the origin of the universe through the major epochs in the story of life.

Chemical Evolution and the Origin of Life: Bibliography 1975

NASA Technical Reports Server (NTRS)

West, Martha W. (Compiler); Koch, Rowena A. (Compiler); Chang, Sherwood (Compiler)

1977-01-01

This bibliography is the sixth annual supplement to the comprehensive bibliography on the same subject which was published in Space Life Sci.We would like to draw attention to a recently published cumulative bibliography on this same subject: Biochemical Origin of Life: Chemistry and Life. Soil and Water and Its Relationship to Origin of Life. MR - Studies of Prebiotic Polypeptides. Energy, Matter, and Life. Prospects for the Future Orientation of Scientific Research. Photochemical Formation of Self Sustaining Coacervates. Photochemical Formation of Self-Sustaining Coacervates. Comparative Study of Abiogenesis of Cysteine and Other Amino Acids Catalyzed by Various Metal Ions. Protein Structure and the Molecular Evolution of Biological Energy Conversion. Origin of Life. Clues from Relations Between Chemical Compositions of Living Organisms and Natural Environments. Shock Synthesis of Amino Acids II.', Origins of Life 6(1-2). Dynamics of the Chemical Evolution of Earth's Primitive Atmosphere. The Mechanisms of Amino Acids Synthesis by High Temperature Shock-Waves. Theory of Chemical Evolution. Physical Foundations of Probability of Biogenesis.

Sex and Race Disparities in Health: Cohort Variations in Life Course Patterns

ERIC Educational Resources Information Center

Yang, Yang; Lee, Linda C.

2009-01-01

This study assesses changes in sex and race disparities in health over the life course and across cohorts by conducting growth curve analyses of nationally representative longitudinal data that spans 15 years. It finds that changes in disparities in depressive symptoms, disability and self-assessments of health across the life course are…

Life Lived Well: A Description of Wellness across the Lifespan of a Senior Woman

ERIC Educational Resources Information Center

Jarnagin, Whitney L.; Woodside, Marianne

2012-01-01

The concept of wellness provides a positive view of life development that can support psychological support and counseling. There is little in the literature about wellness and seniors, especially women. This study describes one senior woman's wellness across the life span by addressing two research questions: (a) What are the experiences of one…

Introduction to special section: early Mars

NASA Technical Reports Server (NTRS)

Clifford, S.; Treiman, A.; Newsom, H.; Farmer, J.

1998-01-01

Ongoing studies of the evolution of the Martian cratered highlands, the nature of the planet's early climate, and the recent announcement of possible evidence of ancient life in the ALH 84001 meteorite have reinvigorated interest in the conditions that prevailed on Mars during its first billion years of geologic history. To address this interest and assess our current understanding of these issues, the Lunar and Planetary Institute hosted a 4-day Conference on Early Mars in Houston in April of 1997. The papers contained in this special section are a product of that meeting. The purpose of the conference was twofold: (1) to consider how impacts, volcanism, and the presence of abundant water affected the physical and chemical environment that existed on Mars 4 Gyr ago, particularly as it related to the nature of the global climate, the origin of the valley networks, the geologic and mineralogic evolution of the surface, the aqueous geochemistry of groundwater, and the existence of local environments that may have been conducive to the development of indigenous life and the preservation of its signature in the geologic record; and (2) to discuss what observations or experiments might he included in future spacecraft missions to test the ideas and expectations arising from purpose 1. While pertinent issues of early atmospheric and solar evolution were also addressed, the primary discussion at the conference focused on the evidence and constraints provided by the geologic records of Earth, the Moon, and Mars and analysis of the SNC meteorites. The papers contained in this special section span the full range of these topics, including the stability of the early atmosphere to erosion by the solar wind, the geologic environment from which the SNC meteorites originated, geomorphic evidence regarding the nature of the early Martian climate and hydrologic cycle, the potential impact of the past and present environment on the preserved signature of ancient life, and a discussion of the capabilities of a lander-based X ray diffraction and fluorescence instrument to assess the potential for past fossilization from the mineralogy of the current local surface environment. The issues raised at the conference, and by the papers included in this special section, will be the focus of ongoing attention as the intensity and scope of Mars exploration increases over the next decade.

The ENVISAT Atmospheric Chemistry mission (GOMOS, MIPAS and SCIAMACHY) - Instrument status and mission evolution

NASA Astrophysics Data System (ADS)

Niro, F.

2009-04-01

The ENVISAT ESA's satellite was launched on a polar orbit on March 2002. It carries on-board three atmospheric chemistry instruments: GOMOS, MIPAS and SCIAMACHY [1]. At the present time, although the mission expected lifetime of 5 years has been already exceeded, all the payload modules are in good to excellent status. The only limiting factor is the available fuel that is used for orbit control manoeuvre. Recently a new strategy was proposed [2] that will allow to save fuel and to extend the mission up to 2013. Following this strategy, the altitude of the orbit will be lowered by 17 km starting from end of 2010 and the inclination will be allowed to drift. The new orbit scenario will result in a new repeating cycle with a variation of the Mean Local Solar Time (MLST). This will have an impact on both the in-flight operations, on the science data and on the mission. The simulations carried out for the atmospheric chemistry instruments show that the new orbit strategy will neither have a significant impact in the instrument operations nor on the quality of the science data. Therefore we expect that the atmospheric mission will continue nominally until the end of the platform life time, providing to the scientist a unique dataset of the most important geophysical parameters (e.g., trace gases, clouds, and aerosol) spanning a time interval of about 11 years. The aim of this paper is to review the overall ENVISAT atmospheric mission status for the past, present and future. The evolution of the instrument performances since launch will be analyzed with focus on the life-limited items monitoring. The tuning of the instrument in-flight operations decided to cope with instrument degradation or scientific needs will be described. The lessons learned on how to operate and monitor the instruments will be highlighted. Finally the expected evolution of the instrument performances until the ENVISAT end-of-life will be discussed. [1] H. Nett, J. Frerick, T. Paulsen, and G. Levrini, "The atmospheric instruments and their applications: GOMOS, MIPAS and SCIAMACHY", ESA Bulletin (ISSN 0376-4265), No. 106, p. 77 - 87 (2001) [2] J. Frerick, B. Duesmann, and M. Canela, "2010 and beyond - The ENVISAT mission extension", Proc. ‘Envisat Symposium 2007', Montreux, Switzerland, 23-27 April 2007 (ESA SP-636, July 2007)

The ENVISAT Atmospheric Chemistry mission (GOMOS, MIPAS and SCIAMACHY) -Instrument status and mission evolution

NASA Astrophysics Data System (ADS)

Dehn, Angelika

The ENVISAT ESA's satellite was launched on a polar orbit on March 2002. It carries on-board three atmospheric chemistry instruments: GOMOS, MIPAS and SCIAMACHY [1]. At the present time, although the mission expected lifetime of 5 years has been already exceeded, all the payload modules are in good to excellent status. The only limiting factor is the available fuel that is used for orbit control manoeuvre. A new strategy was proposed [2] that will allow to save fuel and to extend the mission up to 2013. Following this strategy, the altitude of the orbit will be lowered by 17 km starting from end of 2010 and the inclination will be allowed to drift. The new orbit scenario will result in a new repeating cycle with a variation of the Mean Local Solar Time (MLST). This will have an impact on both the in-flight operations, on the science data and on the mission. The simulations carried out for the atmospheric chemistry instruments show that the new orbit strategy will neither have a significant impact in the instrument operations nor on the quality of the science data. Therefore we expect that the atmospheric mission will continue nominally until the end of the platform life time, providing to the scientist a unique dataset of the most important geophysical parameters (e.g., trace gases, clouds, and aerosol) spanning a time interval of about 11 years. The aim of this paper is to review the overall ENVISAT atmospheric mission status for the past, present and future. The evolution of the instrument performances since launch will be analyzed with focus on the life-limited items monitoring. The tuning of the instrument in-flight operations decided to cope with instrument degradation or scientific needs will be described. The lessons learned on how to operate and monitor the instruments will be highlighted. Finally the expected evolution of the instrument performances until the ENVISAT end-of-life will be discussed. [1] H. Nett, J. Frerick, T. Paulsen, and G. Levrini, "The atmospheric instruments and their applications: GOMOS, MIPAS and SCIAMACHY", ESA Bulletin (ISSN 0376-4265), No. 106, p. 77 -87 (2001) [2] J. Frerick, B. Duesmann, and M. Canela, "2010 and beyond -The ENVISAT mission extension", Proc. `Envisat Symposium 2007', Montreux, Switzerland, 23-27 April 2007 (ESA SP-636, July 2007)

A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation.

PubMed

Ross, Caitlin; Rychtář, Jan; Rueppell, Olav

2015-03-21

Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner's Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual's death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. Copyright © 2015 Elsevier Ltd. All rights reserved.

A structured population model suggests that long life and post-reproductive lifespan promote the evolution of cooperation

PubMed Central

Ross, Caitlin; Rychtář, Jan; Rueppell, Olav

2015-01-01

Social organization correlates with longevity across animal taxa. This correlation has been explained by selection for longevity by social evolution. The reverse causality is also conceivable but has not been sufficiently considered. We constructed a simple, spatially structured population model of asexually reproducing individuals to study the effect of temporal life history structuring on the evolution of cooperation. Individuals employed fixed strategies of cooperation or defection towards all neighbours in a basic Prisoner’s Dilemma paradigm. Individuals aged and transitioned through different life history stages asynchronously without migration. An individual’s death triggered a reproductive event by one immediate neighbour. The specific neighbour was chosen probabilistically according to the cumulative payoff from all local interactions. Varying the duration of pre-reproductive, reproductive, and post-reproductive life history stages, long-term simulations allowed a systematic evaluation of the influence of the duration of these specific life history stages. Our results revealed complex interactions among the effects of the three basic life history stages and the benefit to defect. Overall, a long post-reproductive stage promoted the evolution of cooperation, while a prolonged pre-reproductive stage has a negative effect. In general, the total length of life also increased the probability of the evolution of cooperation. Thus, our specific model suggests that the timing of life history transitions and total duration of life history stages may affect the evolution of cooperative behaviour. We conclude that the causation of the empirically observed association of life expectancy and sociality may be more complex than previously realized. PMID:25637763

Analysis of Environmental Stress Factors Using an Artificial Growth System and Plant Fitness Optimization

PubMed Central

Lee, Meonghun; Yoe, Hyun

2015-01-01

The environment promotes evolution. Evolutionary processes represent environmental adaptations over long time scales; evolution of crop genomes is not inducible within the relatively short time span of a human generation. Extreme environmental conditions can accelerate evolution, but such conditions are often stress inducing and disruptive. Artificial growth systems can be used to induce and select genomic variation by changing external environmental conditions, thus, accelerating evolution. By using cloud computing and big-data analysis, we analyzed environmental stress factors for Pleurotus ostreatus by assessing, evaluating, and predicting information of the growth environment. Through the indexing of environmental stress, the growth environment can be precisely controlled and developed into a technology for improving crop quality and production. PMID:25874206

Cognitive changes and dementia risk after traumatic brain injury: implications for aging military personnel.

PubMed

Vincent, Andrea S; Roebuck-Spencer, Tresa M; Cernich, Alison

2014-06-01

Traumatic brain injury (TBI) is recognized as an important risk factor for the long-term cognitive health of military personnel, particularly in light of growing evidence that TBI increases risk for Alzheimer's disease and other dementias. In this article, we review the neurocognitive and neuropathologic changes after TBI with particular focus on the potential risk for cognitive decline across the life span in military service members. Implications for monitoring and surveillance of cognition in the aging military population are discussed. Additional studies are needed to clarify the factors that increase risk for later life cognitive decline, define the mechanistic link between these factors and dementia, and provide empirically supported interventions to mitigate the impact of TBI on cognition across the life span. Copyright © 2014 The Alzheimer's Association. All rights reserved.

On the Theory of Evolution Versus the Concept of Evolution: Three Observations

PubMed Central

Paz-y-Miño C., Guillermo

2016-01-01

Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Miño and Espinosa (Evo Edu Outreach 2:655-675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller's experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin's own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265-1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic. PMID:26949441

Explicit prediction of hail using multimoment microphysics schemes for a hailstorm of 19 March 2014 in eastern China

NASA Astrophysics Data System (ADS)

Luo, Liping; Xue, Ming; Zhu, Kefeng; Zhou, Bowen

2017-07-01

In the late afternoon of 19 March 2014, a severe hailstorm swept through eastern central Zhejiang province, China. The storm produced golf ball-sized hail, strong winds, and lighting, lasting approximately 1 h over the coastal city of Taizhou. The Advanced Regional Prediction System is used to simulate the hailstorm using different configurations of the Milbrandt-Yau microphysics scheme that predict one, two, or three moments of the hydrometeor particle size distribution. Simulated fields, including accumulated precipitation and maximum estimated hail size (MESH), are verified against rain gauge observations and radar-derived MESH, respectively. For the case of the 19 March 2014 storms, the general evolution is better predicted with multimoment microphysics schemes than with the one-moment scheme; the three-moment scheme produces the best forecast. Predictions from the three-moment scheme qualitatively agree with observations in terms of size and amount of hail reaching the surface. The life cycle of the hailstorm is analyzed, using the most skillful, three-moment forecast. Based upon the tendency of surface hail mass flux, the hailstorm life cycle can be divided into three stages: developing, mature, and dissipating. Microphysical budget analyses are used to examine microphysical processes and characteristics during these three stages. The vertical structures within the storm and their link to environmental shear conditions are discussed; together with the rapid fall of hailstones, these structures and conditions appear to dictate this pulse storm's short life span. Finally, a conceptual model for the life cycle of pulse hailstorms is proposed.

Bedrock composition limits mountain ecosystem productivity and landscape evolution (Invited)

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Hahm, W.; Lukens, C.

2013-12-01

We used measurements of bedrock geochemistry, forest productivity and cosmogenic nuclides to explore connections among lithology, ecosystem productivity and landscape evolution across a lithosequence of 21 sites in the Sierra Nevada Batholith, California. Our sites span a narrow range in elevations and thus share similar climatic conditions. Meanwhile, underlying bedrock varies from granite to diorite and spans nearly the entire range of geochemical compositions observed in Cordilleran granitoids. Land cover varies markedly, from groves of Giant Sequoia, the largest trees on Earth, to pluton-spanning swaths of little or no soil and vegetative cover. This is closely reflected in measures of forest productivity, such as remotely sensed tree-canopy cover, which varies by more than an order of magnitude across our sites and often changes abruptly at mapped contacts between rock types. We find that tree-canopy cover is closely correlated with the concentrations in bedrock of major and minor elements, including several plant-essential nutrients. For example, tree-canopy cover is virtually zero where there is less than 0.3 mg/g phosphorus in bedrock. Erosion rates from these nearly vegetation-free, nutrient deserts are more than 2.5 times slower on average than they are from surrounding, relatively nutrient-rich, soil-mantled bedrock. Thus by influencing soil and forest cover, bedrock nutrient concentrations may provoke weathering-limited erosion and thus may strongly regulate landscape evolution. Our analysis suggests that variations in bedrock nutrient concentrations can also provoke an intrinsic limitation on primary productivity. These limitations appear to apply across all our sites. To the extent that they are broadly representative of conditions in granitic landscapes elsewhere around the world, our results are consistent with widespread, but previously undocumented lithologic control of the distribution and diversity of vegetation in mountainous terrain.

Bubble bursting at an interface

NASA Astrophysics Data System (ADS)

Kulkarni, Varun; Sajjad, Kumayl; Anand, Sushant; Fezzaa, Kamel

2017-11-01

Bubble bursting is crucial to understanding the life span of bubbles at an interface and more importantly the nature of interaction between the bulk liquid and the outside environment from the point of view of chemical and biological material transport. The dynamics of the bubble as it rises from inside the liquid bulk to its disappearance on the interface after bursting is an intriguing process, many aspects of which are still being explored. In our study, we make detailed high speed imaging measurements to examine carefully the hole initiation and growth in bursting bubbles that unearth some interesting features of the process. Previous analyses available in literature are revisited based on our novel experimental visualizations. Using a combination of experiments and theory we investigate the role of various forces during the rupturing process. This work aims to further our current knowledge of bubble dynamics at an interface with an aim of predicting better the bubble evolution from its growth to its eventual integration with the liquid bulk.

Population genomics of intrapatient HIV-1 evolution

PubMed Central

Zanini, Fabio; Brodin, Johanna; Thebo, Lina; Lanz, Christa; Bratt, Göran; Albert, Jan; Neher, Richard A

2015-01-01

Many microbial populations rapidly adapt to changing environments with multiple variants competing for survival. To quantify such complex evolutionary dynamics in vivo, time resolved and genome wide data including rare variants are essential. We performed whole-genome deep sequencing of HIV-1 populations in 9 untreated patients, with 6-12 longitudinal samples per patient spanning 5-8 years of infection. The data can be accessed and explored via an interactive web application. We show that patterns of minor diversity are reproducible between patients and mirror global HIV-1 diversity, suggesting a universal landscape of fitness costs that control diversity. Reversions towards the ancestral HIV-1 sequence are observed throughout infection and account for almost one third of all sequence changes. Reversion rates depend strongly on conservation. Frequent recombination limits linkage disequilibrium to about 100bp in most of the genome, but strong hitch-hiking due to short range linkage limits diversity. DOI: http://dx.doi.org/10.7554/eLife.11282.001 PMID:26652000

The development of counselling psychology in Ireland

PubMed Central

Connolly, Allison; O'Callaghan, Dermot; O'Brien, Owen; Broderick, John; Long, Catherine; O'Grady, Ian

2014-01-01

This paper discusses the distinctive nature of the specialism of counselling psychology and outlines the development of the discipline in Ireland in the context of international developments and its recognition as a professional branch of applied psychology. Today, counselling psychologists are employed in varied clinical and non-clinical settings including health and mental health services (statutory, private and voluntary sector) along with education, forensic, justice, industry and private practices. Counselling psychologist is the primary professional identity of many practising psychologists in Ireland and the Psychological Society of Ireland's Division of Counselling Psychology is the main affiliation of at least 179 members. With its focus on facilitating personal and interpersonal functioning across the life span and its emphasis on the therapeutic process, the specialism continues to bridge the disciplines of psychology, counselling and psychotherapy. In this article, some of the challenges still faced by counselling psychology are explored as it navigates its way through the changing landscape of further development and evolution. PMID:26494940

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kersten, Roland D.; Diedrich, Jolene K.; Yates, III, John R.

Terpenes are ubiquitous natural chemicals with diverse biological functions spanning all three domains of life. In specialized metabolism, the active sites of terpene synthases (TPSs) evolve in shape and reactivity to direct the biosynthesis of a myriad of chemotypes for organismal fitness. As most terpene biosynthesis mechanistically involves highly reactive carbocationic intermediates, the protein surfaces catalyzing these cascade reactions possess reactive regions possibly prone to premature carbocation capture and potentially enzyme inactivation. Here, we show using proteomic and X-ray crystallographic analyses that cationic intermediates undergo capture by conserved active site residues leading to inhibitory self-alkylation. Furthermore, the level of cation-mediatedmore » inactivation increases with mutation of the active site, upon changes in the size and structure of isoprenoid diphosphate substrates, and alongside increases in reaction temperatures. TPSs that individually synthesize multiple products are less prone to self-alkylation then TPSs possessing relatively high product specificity. In total, the results presented suggest that mechanism-based alkylation represents an overlooked mechanistic pressure during the evolution of cation-derived terpene biosynthesis.« less

Dynamics of a pre-lens tear film after a blink: Model, evolution, and rupture

NASA Astrophysics Data System (ADS)

Usha, R.; Anjalaiah, Sanyasiraju, Y. V. S. S.

2013-11-01

A mathematical model is developed to investigate the dynamics and rupture of a pre-lens tear film on a contact lens. The contact lens is modeled as a saturated porous medium of constant, finite thickness and is described by the Darcy-Brinkman equations with stress-jump condition at the interface. The model incorporates the influence of capillarity, gravitational drainage, contact lens properties such as the permeability, the porosity, and the thickness of the contact lens on the evolution and rupture of a pre-lens tear film, when the eyelid has opened after a blink. Two models are derived for the evolution of a pre-lens tear film thickness using lubrication theory and are solved numerically; the first uses shear-free surface condition and the second, the tangentially immobile free surface condition. The results reveal that life span of a pre-lens tear film is longer on a thinner contact lens for all values of permeability and porosity parameter considered. An increase in permeability of contact lens, porosity or stress-jump parameter increases the rate of thinning of the film and advances the rupture time. The viscous-viscous interaction between the porous contact lens and the pre-lens tear film increases the resistance offered by the frictional forces to the rate of thinning of pre-lens tear film. This slows down the thinning process and hence delays the rupture of the film as compared to that predicted by the models of Nong and Anderson [SIAM. J. Appl. Math. 70, 2771-2795 (2010)] derived in the framework of Darcy model.

From Dinosaurs to Modern Bird Diversity: Extending the Time Scale of Adaptive Radiation

PubMed Central

Moen, Daniel; Morlon, Hélène

2014-01-01

What explains why some groups of organisms, like birds, are so species rich? And what explains their extraordinary ecological diversity, ranging from large, flightless birds to small migratory species that fly thousand of kilometers every year? These and similar questions have spurred great interest in adaptive radiation, the diversification of ecological traits in a rapidly speciating group of organisms. Although the initial formulation of modern concepts of adaptive radiation arose from consideration of the fossil record, rigorous attempts to identify adaptive radiation in the fossil record are still uncommon. Moreover, most studies of adaptive radiation concern groups that are less than 50 million years old. Thus, it is unclear how important adaptive radiation is over temporal scales that span much larger portions of the history of life. In this issue, Benson et al. test the idea of a “deep-time” adaptive radiation in dinosaurs, compiling and using one of the most comprehensive phylogenetic and body-size datasets for fossils. Using recent phylogenetic statistical methods, they find that in most clades of dinosaurs there is a strong signal of an “early burst” in body-size evolution, a predicted pattern of adaptive radiation in which rapid trait evolution happens early in a group's history and then slows down. They also find that body-size evolution did not slow down in the lineage leading to birds, hinting at why birds survived to the present day and diversified. This paper represents one of the most convincing attempts at understanding deep-time adaptive radiations. PMID:24802950

The structure of late-life depressive symptoms across a 20-year span: a taxometric investigation.

PubMed

Holland, Jason M; Schutte, Kathleen K; Brennan, Penny L; Moos, Rudolf H

2010-03-01

Past studies of the underlying structure of depressive symptoms have yielded mixed results, with some studies supporting a continuous conceptualization and others supporting a categorical one. However, no study has examined this research question with an exclusively older adult sample, despite the potential uniqueness of late-life depressive symptoms. In the present study, the underlying structure of late-life depressive symptoms was examined among a sample of 1,289 individuals across 3 waves of data collection spanning 20 years. The authors employed a taxometric methodology using indicators of depression derived from the Research Diagnostic Criteria (R. L. Spitzer, J. Endicott, & E. Robins, 1978). Maximum eigenvalue analyses and inchworm consistency tests generally supported a categorical conceptualization and identified a group that was primarily characterized by thoughts about death and suicide. However, compared to a categorical depression variable, depressive symptoms treated continuously were generally better predictors of relevant criterion variables. These findings suggest that thoughts of death and suicide may characterize a specific type of late-life depression, yet a continuous conceptualization still typically maximizes the predictive utility of late-life depressive symptoms.

Lack of robustness of life extension associated with several single-gene P element mutations in Drosophila melanogaster.

PubMed

Mockett, Robin J; Nobles, Amber C

2013-10-01

The hypothesis tested in this study was that single-gene mutations found previously to extend the life span of Drosophila melanogaster could do so consistently in both long-lived y w and standard w (1118) genetic backgrounds. GAL4 drivers were used to express upstream activation sequence (UAS)-responder transgenes globally or in the nervous system. Transgenes associated with oxidative damage prevention (UAS-hSOD1 and UAS-GCLc) or removal (EP-UAS-Atg8a and UAS-dTOR (FRB) ) failed to increase mean life spans in any expression pattern in either genetic background. Flies containing a UAS-EGFP-bMSRA (C) transgene associated with protein repair were found not to exhibit life extension or detectable enhanced green fluorescent protein (EGFP) activity. The presence of UAS-responder transgenes was confirmed by PCR amplification and sequencing at the 5' and 3' end of each insertion. These results cast doubt on the robustness of life extension in flies carrying single-gene mutations and suggest that the effects of all such mutations should be tested independently in multiple genetic backgrounds and laboratory environments.

Carbon Fiber Reinforced Polymer Grids for Shear and End Zone Reinforcement in Bridge Beams

DOT National Transportation Integrated Search

2018-01-01

Corrosion of reinforcing steel reduces life spans of bridges throughout the United States; therefore, using non-corroding carbon fiber reinforced polymer (CFRP) reinforcement is seen as a way to increase service life. The use of CFRP as the flexural ...

Cognitive constraints influence an understanding of life-cycle change.

PubMed

French, Jason A; Menendez, David; Herrmann, Patricia A; Evans, E Margaret; Rosengren, Karl S

2018-05-04

We investigated children's (n = 120; 3- to 11-year-olds) and adults' (n = 18) reasoning about life-cycle changes in biological organisms by examining their endorsements of four different patterns of life-span changes. Participants were presented with two separate tasks: (a) judging possible adult versions of a juvenile animal and (b) judging possible juvenile versions of an adult animal. The stimuli enabled us to examine the endorsement of four different patterns of change: identical growth, natural growth, dramatic change, and speciation. The results suggest that endorsement of the different patterns is influenced by age and familiarity. Young children and individuals confronted with unfamiliar organisms often endorsed an identical growth that emphasizes the stability of features over the life span and between parents and offspring. The results are interpreted as supporting the idea that cognitive constraints influence individuals' reasoning about biological change and that the influence of these constraints is most notable when individuals are young or are presented with unfamiliar biological organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of biochemical data, blood pressure and physical activity between longevity and non-longevity districts in Japan.

PubMed

Mori, Ichiro; Ishizuka, Tatsuo; Morita, Hiroyuki; Matsumoto, Masami; Uno, Yoshihiro; Kajita, Kazuo; Ikeda, Takahide; Fujioka, Kei; Matsubara, Kenji

2008-10-01

There is controversy about longevity-associated factors, including environmental and genetic factors. Clinical and epidemiological studies suggest that multiple risk factors decrease life-span, but there has not been a definitive report regarding the association of risk factors with longevity. The ultimate aim of the present study was to prevent the overwhelming increase in life-style-related diseases by evaluating this association in 2 districts in Japan. Plasma glucose levels, hemoglobin (Hb) A1c, lipids, dehydroepiandrosterone-sulfate, adiponectin and physical activity were examined in 133 subjects (M/F 47/86, 67+/-1 years) in Kokufu, a longevity district (mean life span: 80.4 years according to 2000 Japanese census) and 69 subjects (M/F 29/40, 62+/-1 years) in Miyama, a non-longevity district (mean life span 77.4 years, 2000 census). There were significant differences in systolic and diastolic blood pressures (BPs, p < 0.001), exercise capacity (p < 0.0001) and plasma adiponectin levels (p < 0.04) between the districts. Plasma adiponectin level was significantly correlated with high-density lipoprotein-cholesterol (HDL-C) (r = 0.333, p < 0.0001), triglyceride (TG) (r = -0.161, p < 0.04), HbA1c (r = -0.163, p < 0.03) and HOMA-R (r = -0.163, p < 0.03). Life-style-related factors such as BP, exercise capacity and plasma adiponectin levels might play an important role in longevity, and those of HDL-C and TG, as well as glucose tolerance, might be associated with adiponectin levels.

Neuronal inhibition of the autophagy nucleation complex extends life span in post-reproductive C. elegans

PubMed Central

Byrne, Jonathan; Medina, Rebeca; Kolundžić, Ena; Geisinger, Johannes; Hajduskova, Martina; Tursun, Baris; Richly, Holger

2017-01-01

Autophagy is a ubiquitous catabolic process that causes cellular bulk degradation of cytoplasmic components and is generally associated with positive effects on health and longevity. Inactivation of autophagy has been linked with detrimental effects on cells and organisms. The antagonistic pleiotropy theory postulates that some fitness-promoting genes during youth are harmful during aging. On this basis, we examined genes mediating post-reproductive longevity using an RNAi screen. From this screen, we identified 30 novel regulators of post-reproductive longevity, including pha-4. Through downstream analysis of pha-4, we identified that the inactivation of genes governing the early stages of autophagy up until the stage of vesicle nucleation, such as bec-1, strongly extend both life span and health span. Furthermore, our data demonstrate that the improvements in health and longevity are mediated through the neurons, resulting in reduced neurodegeneration and sarcopenia. We propose that autophagy switches from advantageous to harmful in the context of an age-associated dysfunction. PMID:28882853

Sublgacial Antarctic Lake Environments (SALE)

NASA Astrophysics Data System (ADS)

Kennicutt, M. C.; Bell, R. E.; Priscu, J. C.

2004-12-01

Subglacial Antarctic lake environments are emerging as one of the new frontiers targeted for exploration during the IPY 2007-2009. Several campaigns by various nations are in the early stages of planning and implementation with timelines that will coincide with the IPY. The ambitious interdisciplinary objectives will best be realized by multiple exploration programs investigating diverse subglacial environments continent-wide over the next decade or more. A concerted, multi-target approach wil be taken to advance our understanding of the range of possible lake evolutionary histories; the character of the physical, chemical, and biological niches; the interconnectivity of subglacial lake environments; the coupling of the ice sheet, climate and the evolution of life under the ice; the tectonic settings; and the interplay of biogeochemical cycles. Research and exploration programs spanning the continent will investigate subglacial lake environments of differing ages, evolutionary histories, and biogeochemical settings. The combined efforts will provide a holistic view of these environments over millions of years and under changing climatic conditions. The IPY will provide an opportunity for an intense period of initial exploration that will advance scientific discoveries in glaciology, biogeochemistry, paleoclimate, biology, geology and tectonics, and ecology. While early discoveries and exciting findings are expected during the IPY 2007-2009, a long term sustained program of research and exploration will continue far beyond the IPY. Within the five year period that spans the IPY, specific accomplishments will be targeted, accelerating the research agenda and setting a framework for follow-on studies. Four phases of exploration and discovery are envisioned.

Urban noise and the cultural evolution of bird songs.

PubMed

Luther, David; Baptista, Luis

2010-02-07

In urban environments, anthropogenic noise can interfere with animal communication. Here we study the influence of urban noise on the cultural evolution of bird songs. We studied three adjacent dialects of white-crowned sparrow songs over a 30-year time span. Urban noise, which is louder at low frequencies, increased during our study period and therefore should have created a selection pressure for songs with higher frequencies. We found that the minimum frequency of songs increased both within and between dialects during the 30-year time span. For example, the dialect with the highest minimum frequency is in the process of replacing another dialect that has lower frequency songs. Songs with the highest minimum frequency were favoured in this environment and should have the most effective transmission properties. We suggest that one mechanism that influences how dialects, and cultural traits in general, are selected and transmitted from one generation to the next is the dialect's ability to be effectively communicated in the local environment.

Fitness costs of animal medication: antiparasitic plant chemicals reduce fitness of monarch butterfly hosts.

PubMed

Tao, Leiling; Hoang, Kevin M; Hunter, Mark D; de Roode, Jacobus C

2016-09-01

The emerging field of ecological immunology demonstrates that allocation by hosts to immune defence against parasites is constrained by the costs of those defences. However, the costs of non-immunological defences, which are important alternatives to canonical immune systems, are less well characterized. Estimating such costs is essential for our understanding of the ecology and evolution of alternative host defence strategies. Many animals have evolved medication behaviours, whereby they use antiparasitic compounds from their environment to protect themselves or their kin from parasitism. Documenting the costs of medication behaviours is complicated by natural variation in the medicinal components of diets and their covariance with other dietary components, such as macronutrients. In the current study, we explore the costs of the usage of antiparasitic compounds in monarch butterflies (Danaus plexippus), using natural variation in concentrations of antiparasitic compounds among plants. Upon infection by their specialist protozoan parasite Ophryocystis elektroscirrha, monarch butterflies can selectively oviposit on milkweed with high foliar concentrations of cardenolides, secondary chemicals that reduce parasite growth. Here, we show that these antiparasitic cardenolides can also impose significant costs on both uninfected and infected butterflies. Among eight milkweed species that vary substantially in their foliar cardenolide concentration and composition, we observed the opposing effects of cardenolides on monarch fitness traits. While high foliar cardenolide concentrations increased the tolerance of monarch butterflies to infection, they reduced the survival rate of caterpillars to adulthood. Additionally, although non-polar cardenolide compounds decreased the spore load of infected butterflies, they also reduced the life span of uninfected butterflies, resulting in a hump-shaped curve between cardenolide non-polarity and the life span of infected butterflies. Overall, our results suggest that the use of antiparasitic compounds carries substantial costs, which could constrain host investment in medication behaviours. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Modeling volcano growth on the Island of Hawaii: deep-water perspectives

USGS Publications Warehouse

Lipman, Peter W.; Calvert, Andrew T.

2013-01-01

Recent ocean-bottom geophysical surveys, dredging, and dives, which complement surface data and scientific drilling at the Island of Hawaii, document that evolutionary stages during volcano growth are more diverse than previously described. Based on combining available composition, isotopic age, and geologically constrained volume data for each of the component volcanoes, this overview provides the first integrated models for overall growth of any Hawaiian island. In contrast to prior morphologic models for volcano evolution (preshield, shield, postshield), growth increasingly can be tracked by age and volume (magma supply), defining waxing alkalic, sustained tholeiitic, and waning alkalic stages. Data and estimates for individual volcanoes are used to model changing magma supply during successive compositional stages, to place limits on volcano life spans, and to interpret composite assembly of the island. Volcano volumes vary by an order of magnitude; peak magma supply also varies sizably among edifices but is challenging to quantify because of uncertainty about volcano life spans. Three alternative models are compared: (1) near-constant volcano propagation, (2) near-equal volcano durations, (3) high peak-tholeiite magma supply. These models define inconsistencies with prior geodynamic models, indicate that composite growth at Hawaii peaked ca. 800–400 ka, and demonstrate a lower current rate. Recent age determinations for Kilauea and Kohala define a volcano propagation rate of 8.6 cm/yr that yields plausible inception ages for other volcanoes of the Kea trend. In contrast, a similar propagation rate for the less-constrained Loa trend would require inception of Loihi Seamount in the future and ages that become implausibly large for the older volcanoes. An alternative rate of 10.6 cm/yr for Loa-trend volcanoes is reasonably consistent with ages and volcano spacing, but younger Loa volcanoes are offset from the Kea trend in age-distance plots. Variable magma flux at the Island of Hawaii, and longer-term growth of the Hawaiian chain as discrete islands rather than a continuous ridge, may record pulsed magma flow in the hotspot/plume source.

Coupled Phases and Combinatorial Selection in Fluctuating Hydrothermal Pools: A Scenario to Guide Experimental Approaches to the Origin of Cellular Life

PubMed Central

Damer, Bruce; Deamer, David

2015-01-01

Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution in dehydrated films on mineral surfaces followed by encapsulation and combinatorial selection in a hydrated bulk phase. The dehydrated phase can consist of concentrated eutectic mixtures or multilamellar liquid crystalline matrices. Both conditions organize and concentrate potential monomers and thereby promote polymerization reactions that are driven by reduced water activity in the dehydrated phase. In the case of multilamellar lipid matrices, polymers that have been synthesized are captured in lipid vesicles upon rehydration to produce a variety of molecular systems. Each vesicle represents a protocell, an “experiment” in a natural version of combinatorial chemistry. Two kinds of selective processes can then occur. The first is a physical process in which relatively stable molecular systems will be preferentially selected. The second is a chemical process in which rare combinations of encapsulated polymers form systems capable of capturing energy and nutrients to undergo growth by catalyzed polymerization. Given continued cycling over extended time spans, such combinatorial processes will give rise to molecular systems having the fundamental properties of life. PMID:25780958

The deep-sea under global change.

PubMed

Danovaro, Roberto; Corinaldesi, Cinzia; Dell'Anno, Antonio; Snelgrove, Paul V R

2017-06-05

The deep ocean encompasses 95% of the oceans' volume and is the largest and least explored biome of Earth's Biosphere. New life forms are continuously being discovered. The physiological mechanisms allowing organisms to adapt to extreme conditions of the deep ocean (high pressures, from very low to very high temperatures, food shortage, lack of solar light) are still largely unknown. Some deep-sea species have very long life-spans, whereas others can tolerate toxic compounds at high concentrations; these characteristics offer an opportunity to explore the specialized biochemical and physiological mechanisms associated with these responses. Widespread symbiotic relationships play fundamental roles in driving host functions, nutrition, health, and evolution. Deep-sea organisms communicate and interact through sound emissions, chemical signals and bioluminescence. Several giants of the oceans hunt exclusively at depth, and new studies reveal a tight connection between processes in the shallow water and some deep-sea species. Limited biological knowledge of the deep-sea limits our capacity to predict future response of deep-sea organisms subject to increasing human pressure and changing global environmental conditions. Molecular tools, sensor-tagged animals, in situ and laboratory experiments, and new technologies can enable unprecedented advancement of deep-sea biology, and facilitate the sustainable management of deep ocean use under global change. Copyright © 2017. Published by Elsevier Ltd.

Genomic Changes Associated with Reproductive and Migratory Ecotypes in Sockeye Salmon (Oncorhynchus nerka)

PubMed Central

Veale, Andrew J.

2017-01-01

Mechanisms underlying adaptive evolution can best be explored using paired populations displaying similar phenotypic divergence, illuminating the genomic changes associated with specific life history traits. Here, we used paired migratory [anadromous vs. resident (kokanee)] and reproductive [shore- vs. stream-spawning] ecotypes of sockeye salmon (Oncorhynchus nerka) sampled from seven lakes and two rivers spanning three catchments (Columbia, Fraser, and Skeena) in British Columbia, Canada to investigate the patterns and processes underlying their divergence. Restriction-site associated DNA sequencing was used to genotype this sampling at 7,347 single nucleotide polymorphisms, 334 of which were identified as outlier loci and candidates for divergent selection within at least one ecotype comparison. Sixty-eight of these outliers were present in two or more comparisons, with 33 detected across multiple catchments. Of particular note, one locus was detected as the most significant outlier between shore and stream-spawning ecotypes in multiple comparisons and across catchments (Columbia, Fraser, and Snake). We also detected several genomic islands of divergence, some shared among comparisons, potentially showing linked signals of differential selection. The single nucleotide polymorphisms and genomic regions identified in our study offer a range of mechanistic hypotheses associated with the genetic basis of O. nerka life history variation and provide novel tools for informing fisheries management. PMID:29045601

Life Events, Public Policy and the Economic Vulnerability of Children and the Elderly.

ERIC Educational Resources Information Center

Burkhauser, Richard V.; Duncan, Greg J.

This report uses longitudinal data to provide a dynamic picture of the family income experiences of children and the elderly. In contrast to the image of fairly stable incomes during most life-cycle stages, findings show substantial income volatility at all points in the life span, placing substantial numbers of the population at risk of suffering…