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1

Experimental Evolution Reveals Antagonistic Pleiotropy in Reproductive Timing but Not Life Span in Caenorhabditis elegans  

PubMed Central

Many mutations that dramatically extend life span in model organisms come with substantial fitness costs. Although these genetic manipulations provide valuable insight into molecular modulators of life span, it is currently unclear whether life-span extension is unavoidably linked to fitness costs. To examine this relationship, we evolved a genetically heterogeneous population of Caenorhabditis elegans for 47 generations, selecting for early fecundity. We asked whether an increase in early fecundity would necessitate a decrease in longevity or late fecundity (antagonistic pleiotropy). Caenorhabditis elegans experimentally evolved for increased early reproduction and decreased late reproduction but suffered no total fitness or life-span costs. Given that antagonistic pleiotropy among these traits has been previously demonstrated in some cases, we conclude that the genetic constraint is not absolute, that is, it is possible to uncouple longevity from early fecundity using genetic variation segregating within and among natural populations.

Anderson, Jennifer L.; Reynolds, Rose M.; Morran, Levi T.; Tolman-Thompson, Julie

2011-01-01

2

Tissue signaling pathways in the regulation of life-span and reproduction in females of the linden bug, Pyrrhocoris apterus  

Microsoft Academic Search

Molecular studies on Drosophila melanogaster do not provide consistent results with regard to the hormonal regulation of a trade-off between life-span and fecundity. To unravel the physiological basis of the cost of reproduction without affecting animal's genotype, a new insect model, Pyrrhocoris apterus, was employed. Reproduction was manipulated by surgical ablations of tissues implicated in reproductive endocrinology, namely the pars

Magdalena Hodkova

2008-01-01

3

Late-life fecundity plateaus in Drosophila melanogaster can be explained by variation in reproductive life spans.  

PubMed

Population trajectories of age-specific fecundity in Drosophila melanogaster typically decline with increasing age and then exhibit an upward inflection, or "plateau", at the oldest ages. This pattern has been interpreted as evidence of an evolved and physiologically distinct life history stage in late life. While low levels of fecundity are common in the last few days of life of individual flies, it is unclear that defining a single age as the beginning of a period of low fecundity for the entire cohort is useful, since reproductive life spans vary substantially from fly to fly. Here I analyze published data on survival and reproduction of individual female flies and show that non-linearities in late-life fecundity trajectories arise from a type of demographic selection that occurs when sub-groups with different reproductive life spans (RLS) are mixed. For groups of flies stratified by RLS late-life fecundity declines linearly with age. A simulation incorporating strictly linear decline of individual fecundities and realistic levels of variation in RLS produces late-life plateaus similar to those observed in experiments. Existing population heterogeneity is a sufficient explanation, and no special evolutionary argument is required. For these data survival and reproduction are governed by positive correlations. PMID:24012993

Curtsinger, James W

2013-09-05

4

Genetic correlation between resistance to oxidative stress and reproductive life span in a bird species.  

PubMed

Evolutionary theories propose that aging is the result of a trade-off between self-maintenance and reproduction, and oxidative stress may play a crucial role in such a trade-off. Phenotypic manipulations have revealed that a high investment in reproduction leads to a decline in the organism's resistance to oxidative stress, which could in turn accelerate aging. Here, by using quantitative genetic analyses as a tool to disentangle genetic effects from phenotypic variances, the relationship between resistance to oxidative stress at sexual maturity and two key reproductive life-history traits (i.e., number of breeding events during life and age at last reproduction) was analyzed in cross-fostered zebra finches. The age of last reproduction had high narrow-sense heritability, whereas the number of breeding events and oxidative stress resistance showed medium and low heritabilities, respectively. We detected positive genetic correlations between early resistance to oxidative stress and both life-history traits, suggesting that the efficiency of the antioxidant machinery at maturity may be related to individual reproductive investment throughout lifetime, possibly by influencing the pattern of cellular senescence. Genes encoding for resistance to oxidative stress would have pleiotropic effects on reproductive capacity and aging. Further work is required to confirm this assert. PMID:19817851

Kim, Sin-Yeon; Velando, Alberto; Sorci, Gabriele; Alonso-Alvarez, Carlos

2009-10-05

5

Influence of the quality and quantity of blood ingested on reproductive parameters and life-span in Triatoma infestans (Klug).  

PubMed

In Triatominae, female fecundity and fertility may be affected by age, adult nutritional status (i.e., blood meal source and amount of blood ingested) and number of matings. Triatoma infestans (Klug) is the main vector of Chagas disease in southern South America and considering that reproductive success is intimately associated with the potential for colonizing or re-colonizing new ecotopes in endemic areas, we studied whether the blood meal source and the amount of blood ingested have influence on reproductive parameters. We constitute two groups: couples feeding regularly on guinea pigs and couples feeding regularly on pigeons. We registered quantity of blood ingested, fecundity, fertility, number of matings, days between the first feeding and mating, copula initiation, oviposition initiation and adult life-span. Results showed that females that fed on guinea pigs exhibited high fecundity and fertility, higher number of matings and they needed a lower amount of blood to form an egg. The number of matings and fecundity increased linearly and significantly with the quantity of blood ingested for both meal sources. Results from lineal regression between life-span and fecundity showed a positive and significant relation for both meal sources. The number of matings showed a positive relation with fecundity for both meal sources but significant only for guinea pigs. In T. infestans, the quantity of blood ingested could be a determinant of their reproductive efficiency. This species is mainly adapted to human dwelling and peridomestic structures where there is low host diversity. Considering that this species is in contact with mammals over other food sources, a greater reproductive success may result from an adaptation to this environment. PMID:21672510

Nattero, Julieta; Leonhard, Gustavo; Rodríguez, Claudia S; Crocco, Liliana

2011-06-06

6

Life span shortening  

Microsoft Academic Search

Evidence of life shortening by ionizing radiation in experimental mammals had already been accumulated as early as 20 years ago, so that the first interpretative models could be formulated and discussed. Much more factual evidence has been discussed in the literature since then, and several models based on different approaches have been considered. From a short review of experimental data

Metalli

1979-01-01

7

Effects of salinity on survival, growth, reproductive and life span characteristics of Artemia populations from Urmia Lake and neighboring lagoons.  

PubMed

This study deals with effects of different salinities on the survival, growth, reproductive and lifespan characteristics of three Artemia populations from Urmia Lake and small lagoons at the vicinity of the lake under laboratory conditions. Experimental salinities ranged from 75 to 175 g L(-1). Salinity was proved to have significant impact on the majority of the characters studied in this survey. Growth and survival in bisexual A. urmiana and parthenogenetic Artemia from Lake Urmia were significantly higher with respect to the parthenogenetic Artemia from lagoons at most of the salinities tested. Reproductive characteristics such as total number of broods, total offspring number of offspring in each brood and number of offspring at each day of reproductive period reduced with increasing salinity. Moreover higher salinity prolonged the prereproductive period but shortened the total reproductive period. Higher salinities also affected the percentage of encystment and post-reproductive period, showing significantly higher values in parthenogenetic populations in comparison to bisexual A. urmiana. PMID:18817185

Agh, N; Van Stappen, G; Bossier, P; Sepehri, H; Lotfi, V; Rouhani, S M Razavi; Sorgeloos, P

2008-01-15

8

Platelet life span and apoptosis.  

PubMed

Like many nucleated mammalian cells, the life and death of the anucleate platelet is regulated by Bcl-2 family proteins. Platelets depend on Bcl-x(L) for survival. Bcl-x(L) maintains platelet viability by restraining the killer protein Bak. When Bak is unleashed, it triggers classical intrinsic apoptosis by causing mitochondrial damage. The latter leads to caspase activation and phosphatidylserine (PS) exposure. Platelet apoptosis can be blocked by caspase inhibitors, or by genetic deletion of Bak and its close relative Bax. Perturbations in the platelet apoptosis program lead to changes in platelet life span in vivo. Here, we describe methods to determine platelet life span, enumerate young platelets, and measure hallmarks of platelet apoptosis, such as PS exposure, caspase activation, and mitochondrial dysfunction. PMID:22130700

Josefsson, Emma C; White, Michael J; Dowling, Mark R; Kile, Benjamin T

2012-01-01

9

Life-Span Learning: A Developmental Perspective  

ERIC Educational Resources Information Center

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…

Thornton, James E.

2003-01-01

10

Life-Span Learning: A Developmental Perspective  

ERIC Educational Resources Information Center

|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…

Thornton, James E.

2003-01-01

11

Brain Weight and Life-Span in Primate Species  

Microsoft Academic Search

In haplorhine primates (tarsiers, monkeys, apes, and humans), there is a significant correlation between brain weight and maximum life-span when the effect of body size is removed. There is also a significant correlation in haplorhine primates between brain weight and female age at first reproduction. For strepsirhine primates (lorises and lemurs), there are no significant correlations between brain weight and

John Allman; Todd McLaughlin; Atiya Hakeem

1993-01-01

12

Adaptive prolonged postreproductive life span in killer whales.  

PubMed

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. PMID:22984064

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

2012-09-14

13

Elevated histone expression promotes life span extension.  

PubMed

Changes to the chromatin structure accompany aging, but the molecular mechanisms underlying aging and the accompanying changes to the chromatin are unclear. Here, we report a mechanism whereby altering chromatin structure regulates life span. We show that normal aging is accompanied by a profound loss of histone proteins from the genome. Indeed, yeast lacking the histone chaperone Asf1 or acetylation of histone H3 on lysine 56 are short lived, and this appears to be at least partly due to their having decreased histone levels. Conversely, increasing the histone supply by inactivation of the histone information regulator (Hir) complex or overexpression of histones dramatically extends life span via a pathway that is distinct from previously known pathways of life span extension. This study indicates that maintenance of the fundamental chromatin structure is critical for slowing down the aging process and reveals that increasing the histone supply extends life span. PMID:20832724

Feser, Jason; Truong, David; Das, Chandrima; Carson, Joshua J; Kieft, Jeffrey; Harkness, Troy; Tyler, Jessica K

2010-09-10

14

Life span and fate of basins  

NASA Astrophysics Data System (ADS)

The life span of each main class of sedimentary basin is estimated from published data. Life spans vary over at least three orders of magnitude, from <1 m.y. for trench basins to >100 m.y. for passive-margin and intracratonic basins. The life-span estimates are used to calibrate a chart of basin groups that focuses on the likely basin fates; i.e., depositional, deformational, or thermal. Consequent fates, predetermined by the tectonic setting of a particular basin class, are distinguished from contingent fates, which are independent of basin type. Accretion of trench-basin fill is, for example, a consequent fate, whereas inversion (far-field shortening) of a rift basin is a contingent fate. Life-span data are also used to calibrate the Wilson Cycle and indicate that it has an average duration of ˜260 m.y. This is certainly an underestimate, because basin life spans are an imperfect proxy for the duration of subduction and collision zones.

Woodcock, Nigel H.

2004-08-01

15

Extraordinary long life spans in fruit-feeding butterflies can provide window on evolution of life span and aging  

PubMed Central

Information on the life span of organisms in the field is essential for elucidating the evolution of life span and aging. We present mark-recapture data (>30 000 marked individuals, >4000 recaptured at least once) on forty-seven species of fruit-feeding butterflies in a tropical forest in Uganda. The data reveal adult life spans in the field for several species that are significantly longer than previously recorded in Lepidoptera (butterflies and moths). Longevity records for species of which more than 100 individuals were recaptured ranged from 67 (Bicyclus auricruda) to 293 days (Euphaedra medon). In contrast to the majority of Lepidoptera which are short-lived, these all show exceptionally long life spans, and may thus help to better identify factors that affect aging, particularly when combined with information on temporal patterns in reproduction, strategies to avoid predation, and nutritional ecology. These key traits are readily measurable in butterflies and thus studies on fruit-feeding butterflies have much potential for gaining insight into the evolution of life span and aging, especially given the tradition of field-research on butterflies.

Molleman, F.; Zwaan, B. J.; Brakefield, P.M.; Carey, J. R.

2007-01-01

16

Early Experience: A Life Span Perspective.  

ERIC Educational Resources Information Center

|This paper reviews research findings which are contrary to or inconsistent with the view of early experience as a critical and often irreversible determinant of development. It is suggested that the increasing awareness of the value of a life span perspective is leading to major reevaluation of the role of early experience in development. The…

Goldhaber, Dale; Colman, Molly

17

Lymphocyte Life-Span and Memory  

Microsoft Academic Search

Differentiation of immature T and B cells in the primary lymphoid organs gives rise to a pool of long-lived lymphocytes that recirculate through the secondary lymphoid tissues. On the basis of their surface markers, T and B cells comprise a mixture of naive and memory cells with differing life-spans. Immunization (and vaccination) causes naive lymphocytes to proliferate and differentiate into

Jonathan Sprent; David F. Tough

1994-01-01

18

Neoplastic disease through the human life span  

Microsoft Academic Search

Cancers are different diseases that start andevolve each in its own manner, andtrigger variable responses from the organismdepending upon the neoplastic process under wayand upon the physiopathology of the organism.The clinical incidence of the different cancersis spread through the human life span, withregional differences for each cancer; for manycancers the incidence is increasing at youngerages. More than half of the

A. Macieira-Coelho

2001-01-01

19

Sensorimotor Synchronization across the Life Span  

ERIC Educational Resources Information Center

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…

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

2006-01-01

20

Extending life span by increasing oxidative stress  

Microsoft Academic Search

Various nutritional, behavioral, and pharmacological interventions have been previously shown to extend life span in diverse model organisms, including Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mice, and rats, as well as possibly monkeys and humans. This review aims to summarize published evidence that several longevity-promoting interventions may converge by causing an activation of mitochondrial oxygen consumption to promote increased formation

Michael Ristow; Sebastian Schmeisser

2011-01-01

21

Identifying sexual differentiation genes that affect Drosophila life span  

Microsoft Academic Search

BACKGROUND: Sexual differentiation often has significant effects on life span and aging phenotypes. For example, males and females of several species have different life spans, and genetic and environmental manipulations that affect life span often have different magnitude of effect in males versus females. Moreover, the presence of a differentiated germ-line has been shown to affect life span in several

Jie Shen; Daniel Ford; Gary N Landis; John Tower

2009-01-01

22

Extending Cellular Life-Span with Telomerase  

NSDL National Science Digital Library

This Science magazine site contains full text of a research article: "Extension of Life-Span by Introduction of Telomerase into Normal Human Cells," by Andrea G. Bodnar et. al. (January 16, 1998; Vol 279, No. 5349--available in Adobe Acrobat [.pdf] format only) describes the Telomerase finding and includes a commentary by Titia de Lange of Rockefeller University's Laboratory of Cell Biology and Genetics. There has been a recent finding regarding telomerase, a gene which affects the mechanisms controlling human cell replication. The site above provides general information on telomerase, current telomere research, and the use of telemorase in medical practice. Telomerase increases the life-span of a cell, and is thus central to both aging and cancer.

Bodnar, Andrea G.; Ouellette, Michel.; Frolkis, Maria.; Holt, Shawn E.; Chiu, Choy-Pik.; Morin, Gregg B.

1997-01-01

23

Attitudes Toward Death Across the Life Span.  

ERIC Educational Resources Information Center

|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…

Maiden, Robert; Walker, Gail

24

The evolution of postreproductive life span as an insurance against indeterminacy.  

PubMed

Postreproductive life span remains a puzzle for evolutionary biologists. The explanation of increased inclusive fitness through parental care after reproduction that applies for humans is unrealistic for many species. We propose a new selective mechanism, independent of parental care, which relies on the hypothesis that postreproductive life span can evolve as an insurance against indeterminacy: longer life expectancy reduces the risk of dying by chance before the cessation of reproductive activity. We demonstrate numerically that the duration of evolved postreproductive life span is indeed expected to increase with variability in life span duration. An unprecedented assay of 11 strains of the collembola Folsomia candida shows the existence of (1) postreproductive life span in the absence of parental care; (2) genetic variability in mean postreproductive life span and postreproductive life span variability itself; (3) strong genetic correlation between latter traits. This new explanation brings along the novel idea that loose canalization of a trait (here, somatic life span) can itself act as a selective pressure on other traits. PMID:21967441

Tully, Thomas; Lambert, Amaury

2011-07-14

25

Heat Stress-Induced Life Span Extension in Yeast  

Microsoft Academic Search

The yeastSaccharomyces cerevisiaehas a limited life span that can be measured by the number of times individual cells divide. Several genetic manipulations have been shown to prolong the yeast life span. However, environmental effects that extend longevity have been largely ignored. We have found that mild, nonlethal heat stress extended yeast life span when it was administered transiently early in

Silvian Shama; Chi-Yung Lai; Jill M. Antoniazzi; James C. Jiang; S. Michal Jazwinski

1998-01-01

26

Does the Female Life Span Exceed That of the Male  

Microsoft Academic Search

A survey of all the papers relating to life span in Drosophila melanogaster published in Experimental Gerontology from its origin in 1964 to 1981 shows that, contrary to a common belief, the mean life span of females exceeds that of males in only approximately 50% of the cases. It is shown that mean life span, as it is measured in

F. A. Lints; M. Bourgois; A. Delalieux; J. Stoll; C. V. Lints

1983-01-01

27

Life span of ventricular fibrillation frequencies.  

PubMed

The nature and organization of electrical activity during ventricular fibrillation (VF) are important and controversial subjects dominated by 2 competing theories: the wavebreak and the dominant mother rotor hypothesis. To investigate spatiotemporal characteristics of ventricular fibrillation (VF), transmembrane potentials (V(m)) were recorded from multiple sites of perfused rabbit hearts using a voltage-sensitive dye and a photodiode array or a CCD camera, and the time-frequency characteristics of V(m) were analyzed by short-time fast Fourier transform (FFT) or generalized time-frequency representation with a cone-shaped kernel. The analysis was applied to all pixels to track VF frequencies in time and space. VF consisted of blobs, which are groups of contiguous pixels with a common frequency and an ill-defined shape. At any time t, several VF frequency blobs coexisted in the field of view, and the number of coexisting blobs was on average 5.9+/-2.1 (n=8 hearts) as they appeared and disappeared discontinuously with time and were not fixed in space. The life span of frequency blobs from birth to either annihilation or breakup to another frequency had a half-life of 0.39+/-0.13 second (n=4 hearts). The Ca2+ channel blocker nifedipine increased the stability of VF frequencies and reduced the number of frequency blobs progressing to a single frequency. In conclusion, VF consists of dynamically changing frequency blobs, which have a short life span and can be modified by pharmacological interventions, suggesting that VF is maintained by dynamically changing multiple wavelets. PMID:12193467

Choi, Bum-Rak; Nho, Wonchul; Liu, Tong; Salama, Guy

2002-08-23

28

Dietary and lifestyle predictors of age at natural menopause and reproductive span in the Shanghai Women's Health Study  

PubMed Central

Objectives: Modifiable factors predicting the onset of menopause, a transition with important implications for women's health, have not been fully characterized. We evaluated the impact of dietary, lifestyle and reproductive factors on age at natural menopause and reproductive span in Chinese women. Design: Study participants were Chinese women aged 40–70 who experienced natural menopause and participated in a population-based, prospective study, the Shanghai Women's Health Study (n=33,054). Dietary intakes at the baseline survey were assessed by food-frequency questionnaire. Regression (?) coefficients, calculated by multivariable linear regression, were used to estimate the effects of dietary, lifestyle, and reproductive patterns on age at menopause and the number of reproductive years, adjusting for potential confounding factors. Results: Early menarche, younger age at first-live birth, older age at last live-birth, longer duration of breastfeeding, and higher parity were associated with longer reproductive years (Ptrend<0.01 for all). Higher body-mass index at age 20, mid-life weight gain, and leisure-time physical activity during adolescence and adulthood predicted later menopause and longer reproductive span (Ptrend<0.01 for all). Total intakes of calories, fruits, protein, and possibly carbohydrates were positively associated with later menopause (Ptrend <0.05 for all) and longer reproductive span [Ptrend <0.05, except for carbohydrates (Ptrend =0.06)], and long-term tea consumption predicted longer reproductive span (Ptrend =0.03). Vegetable, fat, soy, and fiber intakes did not significantly affect reproductive span or age at menopause. Smoking was inversely related to both age at menopause and reproductive span (Ptrend <0.01). Conclusions: In addition to reproductive factors, intakes of fruit, protein, smoking, and tea consumption, lifetime patterns of physical activity, and weight gain influenced the onset of menopause and/or reproductive span in Chinese women.

Dorjgochoo, Tsogzolmaa; Kallianpur, Asha; Gao, Yu-Tang; Cai, Hui; Yang, Gong; Li, Honglan; Zheng, Wei; Shu, Xiao Ou

2008-01-01

29

[Caloric restriction increases life span in sterile and non-sterile D. melanogaster females: systems analysis].  

PubMed

Experiments show that moderate caloric restriction in normal (non-sterile) fruit flies results in the increase of life span. It has been found recently that life span increases under caloric restriction also in sterile Drosophila females. This fact was explained by remodeling of metabolism due to insulin signaling. In this paper a hypothesis is put forward that under caloric restriction in the organism, the energy arrival decreases so that the stationary state must be restored. To achieve this, reproduction is reducing, remodeling of metabolism and the increasing of substrates output from the gastrointestinal tract start. The increase of life span can be just a side effect of these processes. Simulation demonstrates that the experimentally observed life span increasing in non-sterile fly females under caloric restriction can be explained exclusively by the reducing reproduction. PMID:21033371

Novosel'tsev, V N; Novosel'tseva, Zh A

2010-01-01

30

Failure of infinite life span human cells from different immortality complementation groups to yield finite life span hybrids.  

PubMed

The observation that fusion of infinite life span cells with finite life span cells produces hybrid cells with finite life spans led to the conclusion that an infinite life span in culture is a recessive trait resulting from loss of the function of a gene or genes that contribute to an active program for cellular senescence. Furthermore, finding that certain pairs of infinite life span cells, when fused to one another, can complement each other to yield finite life span hybrids allowed 30 infinite life span cell lines to be assigned to four immortality complementation groups (Pereira-Smith and Smith, 1988, Proc. Natl. Acad. Sci. U.S.A., 85:6042). In the present study, we fused a chromosomally stable, near diploid, morphologically normal, infinite life span cell strain, designated MSU-1.1, with its normal, finite life span, precursor cell strain and obtained finite life span hybrids, as expected if infinite life span in culture is a recessive trait. However, 14 of the 14 hybrids from our fusions of MSU-1.1 cells with representative cell lines from each of the four immortality complementation groups, and 38 of the 39 hybrids from our fusions of infinite life span cells that have been reported to complement each other, failed to exhibit finite life spans. This result suggests that infinite life span cells cannot complement each other to yield finite life span hybrids. In examining this unexpected result, we obtained evidence that long-term dual drug selection can be deleterious to hybrid cells even though they carry resistance markers for both drugs, indicating that the cell death of such hybrids observed in other studies may have resulted from the cytotoxic effect of long-term drug selection, rather than from senescence. PMID:8138583

Ryan, P A; Maher, V M; McCormick, J J

1994-04-01

31

Stress proteins in aging and life span.  

PubMed

Heat shock proteins (HSP) are molecular chaperones and have been implicated in longevity and aging in many species. Their major functions include chaperoning misfolded or newly synthesised polypeptides, protecting cells from proteotoxic stress, and processing of immunogenic agents. These proteins are expressed constitutively and can be induced by stresses such as heat, oxidative stress and many more. The induction of HSP in aging could potentially maintain protein homeostasis and longevity by refolding the damaged proteins which accumulate during aging and are toxic to cells. HSP are shown to increase life span in model organisms such as Caenorhabditis elegans and decrease aging-related proteotoxicity. Thus, decrease in HSP in aging is associated with disruption of cellular homeostasis which causes diseases such as cancer, cell senescence and neurodegeneration. HSP levels are decreased with aging in most organs including neurons. Aging also causes attenuation or alteration of many signalling pathways as well as the expression of transcription factors such as heat shock factor (HSF). The alteration in regulation and synthesis of Forkhead box O3a (FoxO3a) family of transcription factors as well as major antioxidant enzymes (manganese superoxide dismutase, catalase) are also seen in aging. Among many signalling mechanisms involved in altering longevity and aging, the insulin/IGF-1 pathway and the Sir2 deacetylase are highly significant. This review enquires into the role of some of these pathways in longevity/aging along with HSP. PMID:23742046

Murshid, Ayesha; Eguchi, Takanori; Calderwood, Stuart K

2013-06-06

32

[Effect of Limonium bicolor on bombyxmori life-span].  

PubMed

The effect of limonium bicolor decoction (LBD) (1%, 5%, 10%) on the life-span of bombyxmori was investigated. It was found that LBD could obviously prolong not only average life-span and average of highest life-span of both female bombyxmori and moth, but also the daration of female silkworm stage. Furthermore, LBD clud be antianoxiasis and hunger-resistant, these results showed that BLD could promise longevity. PMID:12567942

Zhang, H; Wang, J; Li, S; Huang, L

1998-03-01

33

Effect of melatonin and pineal peptide preparation epithalamin on life span and free radical oxidation in Drosophila melanogaster  

Microsoft Academic Search

It was shown previously that epithalamin delays age-related changes in reproductive and immune systems and increases the life span of mice and rats. These effects could be mediated by stimulating influences of epithalamin on synthesis and secretion of melatonin and on free radical processes. A comparative study on the effect of epithalamin and melatonin on both the life span of

Vladimir N Anisimov; Sergey V Mylnikov; Tatyana I Oparina; Vladimir Kh Khavinson

1997-01-01

34

A Motivational Theory of Life-Span Development  

ERIC Educational Resources Information Center

|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…

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

35

Developmental Regulation across the Life Span: Toward a New Synthesis  

ERIC Educational Resources Information Center

|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…

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

2013-01-01

36

A Motivational Theory of Life-Span Development  

ERIC Educational Resources Information Center

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…

Heckhausen, Jutta; Wrosch, Carsten; Schulz, Richard

2010-01-01

37

Partner Preferences Across the Life Span: Online Dating by Older Adults  

Microsoft Academic Search

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

Sheyna Sears-Roberts Alterovitz; Gerald A. Mendelsohn

2009-01-01

38

Partner Preferences Across the Life Span: Online Dating by Older Adults  

Microsoft Academic Search

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

Sheyna Sears-Roberts Alterovitz; Gerald A. Mendelsohn

2011-01-01

39

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

PubMed Central

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.

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

2012-01-01

40

Neuronal expression of Mgat1 rescues the shortened life span of Drosophila Mgat11 null mutants and increases life span  

PubMed Central

The enzyme UDP-GlcNAc:?3-D-mannoside ?1,2-N-acetylglucosaminyltransferase I (GnT1, encoded by Mgat1) controls the synthesis of paucimannose N-glycans in Drosophila. We have previously reported that null mutations in Drosophila Mgat1 are viable but exhibit defects in locomotion, brain abnormalities, and a severely reduced life span. Here, we show that knockdown of Mgat1 in the central nervous system (CNS) of wild-type flies decreases locomotor activity and life span. This phenotype is similar to that observed in Drosophila Mgat11 null mutants, demonstrating that Mgat1 is required in the CNS. We also found that neuronal expression of a wild-type Mgat1 transgene rescued the shortened life span of Mgat11 null mutants and resulted in a dramatic 135% increase in mean life span relative to genetically identical controls. Neuronal expression of a wild-type Mgat1 transgene in wild-type flies resulted in a modest 9% increase in mean life span relative to genetically identical controls. In both Mgat11 null mutants and wild-type flies, neuronal expression of wild-type Mgat1 transgene resulted in a significant increase in GnT1 activity and resistance to oxidative stress. Whereas dietary restriction is not absolutely essential for the increased life span, it plays a role in the process. Interestingly, we observe a direct correlation between GnT1 activity and mean life span up to a maximum of ~136 days, showing that the ability of GnT1 activity to increase life span is limited. Altogether, these observations suggest that Mgat1-dependent N-glycosylation plays an important role in the control of Drosophila life span.

Sarkar, Mohan; Iliadi, Konstantin G.; Leventis, Peter A.; Schachter, Harry; Boulianne, Gabrielle L.

2010-01-01

41

Extending the Human Life Span: Social Policy and Social Ethics.  

National Technical Information Service (NTIS)

This document contains some papers and discussions dealing with extension of the human life span, which emanated from a conference attended by social and biological scientists, policymakers, and social ethicists. Authors were asked to focus upon the gener...

B. L. Neugarten R. J. Havighurst

1977-01-01

42

Dietary restriction: critical co-factors to separate health span from life span benefits.  

PubMed

Dietary restriction (DR), typically a 20%-40% reduction in ad libitum or "normal" nutritional energy intake, has been reported to extend life span in diverse organisms, including yeast, nematodes, spiders, fruit flies, mice, rats, and rhesus monkeys. The magnitude of the life span enhancement appears to diminish with increasing organismal complexity. However, the extent of life span extension has been notoriously inconsistent, especially in mammals. Recently, Mattison et al. reported that DR does not extend life span in rhesus monkeys in contrast to earlier work of Colman et al. Examination of these papers identifies multiple potential confounding factors. Among these are the varied genetic backgrounds and composition of the "normal" and DR diets. In monkeys, the correlation of DR with increased health span is stronger than that seen with life span and indeed may be separable. Recent mechanistic studies in Drosophila implicate non-genetic co-factors such as level of physical activity and muscular fatty acid metabolism in the benefits of DR. These results should be followed up in mammals. Perhaps levels of physical activity among the cohorts of rhesus monkeys contribute to inconsistent DR effects. To understand the maximum potential benefits from DR requires differentiating fundamental effects on aging at the cellular and molecular levels from suppression of age-associated diseases, such as cancer. To that end, it is important that investigators carefully evaluate the effects of DR on biomarkers of molecular aging, such as mutation rate and epigenomic alterations. Several short-term studies show that humans may benefit from DR in as little as 6 months, by achieving lowered fasting insulin levels and improved cardiovascular health. Optimized health span engineering will require a much deeper understanding of DR. PMID:22963324

Mendelsohn, Andrew R; Larrick, James W

2012-10-01

43

Heritability of life span is largely sex limited in Drosophila.  

PubMed

Abstract Males and females differ with respect to life span and rate of aging in most animal species. Such sexual dimorphism can be associated with a complex genetic architecture, where only part of the genetic variation is shared between the sexes. However, the extent to which this is true for life span and aging is not known, because studies of life span have given contradictory results and aging has not been studied from this perspective. Here we investigate the additive genetic architecture of life span and aging in Drosophila melanogaster. We find substantial amounts of additive genetic variation for both traits, with more than three-quarters of this variation available for sex-specific evolutionary change. This result shows that the sexes have a profoundly different additive genetic basis for these traits, which has several implications. First, it translates into an, on average, three-times-higher heritability of life span within, compared to between, the sexes. Second, it implies that the sexes are relatively free to evolve with respect to these traits. And third, as life span and aging are traits that integrate over all genetic factors that contribute to mortal disease, it also implies that the genetics of heritable disease differs vastly between the sexes. PMID:24107372

Lehtovaara, Anne; Schielzeth, Holger; Flis, Ilona; Friberg, Urban

2013-09-12

44

Legacy of life-span dog studies  

SciTech Connect

Over the past 35 y, the U.S. Department of Energy and its predecessor agencies have sponsored studies using beagle dogs to determine the effects of radiation, administered in various forms, by various routes, at various levels of intensity, and in various patterns of exposure, with observations continuing for the life of the animal. These studies have been conducted at several laboratories; some are completed, others are still in progress. Taken as a whole, these studies constitute an experiment of potentially enormous significance to the more complete understanding of the biological effects of radiation.

Thompson, R.C.

1988-08-01

45

Integrating the Life Course and Life-Span: Formulating Research Questions with Dual Points of Entry  

Microsoft Academic Search

Although life-span psychology and life course sociology share much in common, they also differ in significant ways. One such difference concerns their points of entry into the study of human behavior: When formulating questions, life-span psychologists typically begin with cognitive, emotional, or motivational characteristics of the person, and life course sociologists often begin with social context and roles. Yet by

Michael J. Shanahan; Erik Porfelli

2002-01-01

46

Regulation of yeast replicative life span by thiol oxidoreductases  

PubMed Central

Thiol-based redox reactions are involved in the regulation of a variety of biological functions, such as protection against oxidative stress, signal transduction and protein folding. Some proteins involved in redox regulation have been shown to modulate life span in organisms from yeast to mammals. To assess the role of thiol oxidoreductases in aging on a genome-wide scale, we analyzed the replicative life span of yeast cells lacking known and candidate thiol oxidoreductases. The data suggest the role of several pathways in regulation of yeast aging, including thioredoxin reduction, protein folding and degradation, peroxide reduction, PIP3 signaling, and ATP synthesis.

Hacioglu, Elise; Esmer, Isil; Fomenko, Dmitri E.; Gladyshev, Vadim N.; Koc, Ahmet

2011-01-01

47

Decision-making heuristics and biases across the life span  

PubMed Central

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.

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

2013-01-01

48

Sex role endorsement among homosexual men across the life span  

Microsoft Academic Search

This study assessed the sex role endorsement of homosexual men at different ages across the life span. A sample of homosexual men from dignity chapters in the northeastern, midwestern, southern, southwestern, and western United States was mailed a demographic questionnaire and the Bem Sex Role Inventory. Respondents were classified into four age brackets and categorized as androgynous, masculine, feminine, and

Bryan E. Robinson; Patsy Skeen; Carol Flake-Hobson

1982-01-01

49

Body image across the adult life span: stability and change  

Microsoft Academic Search

By far, the majority of studies investigating body image in adults have drawn samples from college populations within a very narrow age range. The purpose of the present paper is to review empirical research on the body image of adults older than the typical college student. There are marked changes in appearance across the adult life span, especially for women,

Marika Tiggemann

2004-01-01

50

Neuromodulation of Behavioral and Cognitive Development across the Life Span  

ERIC Educational Resources Information Center

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…

Li, Shu-Chen

2012-01-01

51

Suicide Notes of Adolescents: A Life-span Comparison  

Microsoft Academic Search

Utilizing suicide notes as the data source, this study begins to explore some psychological dimensions in adolescent suicide and to identify the differences and similarities of suicide across the life span. The method called for 80 notes, representing four developmental ages (i.e., adolescents, young adults, middle adults, old adults) to be analyzed for specific protocols on eight categories, i.e., unbearable

Antoon A. Leenaars; Erik Jan De Wilde; Susanne Wenckstern; Michael Kral

2001-01-01

52

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

ERIC Educational Resources Information Center

|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…

Briggs, Michele Kielty; Dixon, Andrea L.

2013-01-01

53

Neuromodulation of Behavioral and Cognitive Development across the Life Span  

ERIC Educational Resources Information Center

|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…

Li, Shu-Chen

2012-01-01

54

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

ERIC Educational Resources Information Center

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…

Fallahi, Carolyn R.

2008-01-01

55

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

ERIC Educational Resources Information Center

|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…

Fallahi, Carolyn R.

2008-01-01

56

Exceptional Cognitive Development: A Life Span Developmental Approach.  

ERIC Educational Resources Information Center

|The belief that gifted children are more likely to have personality problems than "normal" individuals is not supported by research, but the image of the disturbed gifted child persists. This paper reviews research from a life-span developmental perspective to examine why this image persists. The paper critically examines the research of L.…

Flom, Peter

57

Chromosome dosage as a life span determinant in Caenorhabiditis elegans  

Microsoft Academic Search

Caenorhabiditis elegans males live longer than hermaphrodites when cultured individually. Since hermaphrodites contain a pair of X chromosomes (XX) and males are XO (there is no Y chromosome in C. elegans), we questioned whether chromosomal differences per se might impact life span. The use of mutations in the sex-determination genes tra-1 and her-1 allowed us to uncouple sexual phenotype from

Phil S. Hartman; Naoaki Ishii

2007-01-01

58

Life Stress and Transitions in the Life Span  

Microsoft Academic Search

\\u000a The traditional life cycle of human beings include infancy, childhood, adolescence, and adulthood. Transitions exist within\\u000a each of the life cycles and such transitions produce stress. Life has many stressful life events that mark the movement from\\u000a one condition or cycle to another, and they produce substantial challenges in the lives of human beings. The purpose of this\\u000a volume is

Thomas W. Miller

59

Life span correlates with population dynamics in perennial herbaceous plants.  

PubMed

Survival and fecundity are basic components of demography and therefore have a strong influence on population dynamics. These two key parameters and their relationship are crucial to understand the evolution of life histories. It remains, however, to be empirically established how life span, fecundity, and population dynamics are linked in different organism groups. We conducted a comparative study based on demographic data sets of 55 populations of 23 perennial herbs for which structured demographic models and among-year natural variation in demographic attributes were available. Life span (from 4 to 128 yr old), estimated by using an algorithm, was inversely correlated with the deviance of the population growth rate from equilibrium as well as with among-year population fluctuations. Temporal variability was greater for short-lived species than for the long-lived ones because fecundity was more variable than survival and relatively more important for population dynamics for the short-lived species. The relationship between life span and population stability suggests that selection for longevity may have played an important role in the life history evolution of plants because of its ability to buffer temporal fluctuations in population size. PMID:21632350

García, María B; Picó, F Xavier; Ehrlén, Johan

2008-02-01

60

Does Dietary Restriction Reduce Life Span in Male Fruit-feeding Butterflies?  

PubMed Central

Male life history and resource allocation is not frequently studied in aging and life span research. Here we verify that males of long-lived fruit-feeding butterfly species have reduced longevity on restricted diets (Beck 2007 Oecologia), in contrast to the common finding of longevity extension in dietary restriction experiments in Drosophila and some other organisms. Males of some of the most long-lived species of fruit-feeding butterflies were collected from Kibale Forest, Uganda, and kept on diets of either sugar or mashed banana. Seven out of eight species had non-significantly longer life spans on mashed banana diets. Data analysis using a time-varying Cox-model with species as covariate showed that males had reduced survival on the sugar diet during the first 35 days of captive life, but the effect was absent or reversed at more advanced ages. These results challenge the generality of dietary restriction as a way to extend life span in animals. We argue that such studies on males are promising tools for better understanding life history evolution and aging because males display a wider variety of tactics for obtaining reproductive success than females.

Molleman, Freerk; Ding, Jimin; Boggs, Carol L.; Carey, James R.; Arlet, Malgorzata E.

2009-01-01

61

Sex Differences in Sustained Attention Across the Adult Life Span  

Microsoft Academic Search

We used a life span sample of 18- to 91-year-old men (n = 176) and women (n = 108) to investigate sex differences and the effect of age on sex differences in performance and arousal during a 62-min no-memory-demand sensory vigilance task (Mackworth's Clock-Test). We observed sex differences in target response time and on measures of autonomic arousal; women were

Leonard M. Giambra; Reginald E. Quilter

1989-01-01

62

Rapamycin extends life- and health span because it slows aging  

PubMed Central

Making headlines, a thought-provocative paper by Neff, Ehninger and coworkers claims that rapamycin extends life span but has limited effects on aging. How is that possibly possible? And what is aging if not an increase of the probability of death with age. I discuss that the JCI paper actually shows that rapamycin slows aging and also extends lifespan regardless of its direct anti-cancer activities. Aging is, in part, MTOR-driven: a purposeless continuation of developmental growth. Rapamycin affects the same processes in young and old animals: young animals' traits and phenotypes, which continuations become hyperfunctional, harmful and lethal later in life.

Blagosklonny, Mikhail V.

2013-01-01

63

[Life-span-developmental psychology and gerontology (author's transl)].  

PubMed

The recognition that aging processes are considerably influenced by the individuals' life-course from birth on can be traced to antiquity. One of the first attempts of scientific study of the entire life-course was started by Charlotte Bühler (1933). Already in 1951, Thomae emphasized the necessary extension of Developmental Psychology from its restriction to childhood into covering the entire life-span, and initiated numerous empirical studies working with the biographical method. Thus, the "life-span-orientation" of Developmental Psychology, recently ascribed to P.B. Baltes, is rather a rediscovered conceptualization than a genuine 'new' idea. Following this evaluation of the historical roots and origins of "life-span-developmental-psychology", a review of empirical biographical studies is presented, which emphasize a conceptualization of behavior in older age at the intersection of past experience, current situation, and future time perspective of the individual. As an example it is discussed how the mother experiences and reacts to her (last) child's leaving home ("empty-nest-reaction"). In addition, "sociogendtic risk-factors" (Eitner) are discussed, as well as the biographical interdependency of mental and physical activity, of multiple interests and social contacts. Stating the empirical evidence for the strong influence of behavior and experience in younger and middle adulthood on the individual's well-being in older age must not lead to the conclusion that the situation of the aged person cannot be changed: the older individual certainly has the ability and opportunity to learn, to be flexible, and to change--within the given boundaries--his current situation. PMID:6109462

Lehr, U

1980-06-01

64

C. elegans VANG-1 modulates life span via insulin/IGF-1-like signaling.  

PubMed

The planar cell polarity (PCP) pathway is highly conserved from Drosophila to humans and a PCP-like pathway has recently been described in the nematode Caenorhabditis elegans. The developmental function of this pathway is to coordinate the orientation of cells or structures within the plane of an epithelium or to organize cell-cell intercalation required for correct morphogenesis. Here, we describe a novel role of VANG-1, the only C. elegans ortholog of the conserved PCP component Strabismus/Van Gogh. We show that two alleles of vang-1 and depletion of the protein by RNAi cause an increase of mean life span up to 40%. Consistent with the longevity phenotype vang-1 animals also show enhanced resistance to thermal- and oxidative stress and decreased lipofuscin accumulation. In addition, vang-1 mutants show defects like reduced brood size, decreased ovulation rate and prolonged reproductive span, which are also related to gerontogenes. The germline, but not the intestine or neurons, seems to be the primary site of vang-1 function. Life span extension in vang-1 mutants depends on the insulin/IGF-1-like receptor DAF-2 and DAF-16/FoxO transcription factor. RNAi against the phase II detoxification transcription factor SKN-1/Nrf2 also reduced vang-1 life span that might be explained by gradual inhibition of insulin/IGF-1-like signaling in vang-1. This is the first time that a key player of the PCP pathway is shown to be involved in the insulin/IGF-1-like signaling dependent modulation of life span in C. elegans. PMID:22359667

Honnen, Sebastian J; Büchter, Christian; Schröder, Verena; Hoffmann, Michael; Kohara, Yuji; Kampkötter, Andreas; Bossinger, Olaf

2012-02-16

65

The life cycle and life span of Namibian fairy circles.  

PubMed

In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called "fairy circles" are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations. Circles are not permanent; their vegetative and physical attributes allow them to be arranged into a life history sequence in which circles appear (birth), develop (mature) and become revegetated (die). Occasionally, they also enlarge. The appearance and disappearance of circles was confirmed from satellite images taken 4 years apart (2004, 2008). The frequency of births and deaths as a fraction of the total population of circles allowed the calculation of an approximate turnover rate, and from this, an estimate of circle lifespan. Lifespan appeared to vary with circle size, with small circles averaging about 24 years, and larger ones 43-75 years. Overall lifespan averaged about 41 yr. A second, independent estimate of lifespan was made by revisiting circles 2 to 9 years after their clear status had been confirmed. This resulted in a lifespan estimate of about 60 years. Any causal explanation of fairy circles must include their birth, development and death, their mean lifespan and the variation of their features under different conditions. PMID:22761663

Tschinkel, Walter R

2012-06-27

66

Absence of Strong Heterosis for Life Span and Other Life History Traits in Caenorhabditis Elegans  

PubMed Central

We have examined crosses between wild-type strains of Caenorhabditis elegans for heterosis effects on life span and other life history traits. Hermaphrodites of all wild strains had similar life expectancies but males of two strains had shorter life spans than hermaphrodites while males of two other strains lived longer than hermaphrodites. F(1) hermaphrodite progeny showed no heterosis while some heterosis for longer life span was detected in F(1) males. F(1) hybrids of crosses between two widely studied wild-type strains, N2 (var. Bristol) and Berg BO (var. Bergerac), were examined for rate of development, hermaphrodite fertility, and behavior; there was no heterosis for these life history traits. Both controlled variation of temperature and uncontrolled environmental variation affected the length of life of all genotypes. Significant G X E effects on life span were observed in comparisons of N2 and Berg BO hermaphrodites, or N2 hermaphrodites and males, or N2 and a Ts mutant strain (DH26). Nevertheless, within an experiment, environmental variation was minimal and life spans were quite replicable.

Johnson, T. E.; Hutchinson, E. W.

1993-01-01

67

A malathion resistance gene associated with increased life span of the rusty grain beetle, Cryptolestes ferrugineus (Coleoptera: Cucujidae).  

PubMed

The life span of the rusty grain beetle, Cryptolestes ferrugineus, was determined at 30 degrees C, 75% relative humidity (RH) for virgin and mated adults of a malathion-resistant strain (BC6RR), a malathion-susceptible strain (SS), the F1 progeny of a cross between resistant females and susceptible males (RS), and an outbred strain (GV). The BC6RR strain was derived from the SS strain by incorporating the malathion resistance gene into the susceptible genome with six backcrosses and recovery of heterozygous resistant F1 adults between crosses. The mean life span of virgin, malathion-resistant adults (BC6RR and RS) was 37 weeks; the mean life span of virgin, susceptible adults (SS and GV) was 32 weeks. Resistant virgin adults lived significantly longer (15-16%) than susceptible virgin adults, and mated resistant adults lived significantly longer (3-20%) than mated susceptible adults (p < .05). Since C. ferrugineus has a relatively long reproductive period and females with the longest life spans produce the most offspring, life span can be considered an important component of fitness in this insect. The malathion resistance gene did not reduce fitness, and this gene or genes closely linked to it may be responsible for increasing life span in C. ferrugineus. PMID:7814781

White, N D; Bell, R J

1995-01-01

68

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

PubMed

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. PMID:19485668

Alterovitz, Sheyna Sears-Roberts; Mendelsohn, Gerald A

2009-06-01

69

AMPK?1 Deletion Shortens Erythrocyte Life Span in Mice  

PubMed Central

AMP-activated protein kinase (AMPK) is an energy sensor essential for maintaining cellular energy homeostasis. Here, we report that AMPK?1 is the predominant isoform of AMPK in murine erythrocytes and mice globally deficient in AMPK?1 (AMPK?1?/?), but not in those lacking AMPK?2, and the mice had markedly enlarged spleens with dramatically increased proportions of Ter119-positive erythroid cells. Blood tests revealed significantly decreased erythrocyte and hemoglobin levels with increased reticulocyte counts and elevated plasma erythropoietin concentrations in AMPK?1?/? mice. The life span of erythrocytes from AMPK?1?/? mice was less than that in wild-type littermates, and the levels of reactive oxygen species and oxidized proteins were significantly increased in AMPK?1?/? erythrocytes. In keeping with the elevated oxidative stress, treatment of AMPK?1?/? mice with the antioxidant, tempol, resulted in decreased reticulocyte counts and improved erythrocyte survival. Furthermore, the expression of Foxo3 and reactive oxygen species scavenging enzymes was significantly decreased in erythroblasts from AMPK?1?/? mice. Collectively, these results establish an essential role for AMPK?1 in regulating oxidative stress and life span in erythrocytes.

Wang, Shaobin; Dale, George L.; Song, Ping; Viollet, Benoit; Zou, Ming-hui

2010-01-01

70

Extending Healthy Life SpanâÂÂFrom Yeast to Humans  

NSDL National Science Digital Library

When the food intake of organisms such as yeast and rodents is reduced (dietary restriction), they live longer than organisms fed a normal diet. A similar effect is seen when the activity of nutrient-sensing pathways is reduced by mutations or chemical inhibitors. In rodents, both dietary restriction and decreased nutrient-sensing pathway activity can lower the incidence of age-related loss of function and disease, including tumors and neurodegeneration. Dietary restriction also increases life span and protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and in humans it causes changes that protect against these age-related pathologies. Tumors and diabetes are also uncommon in humans with mutations in the growth hormone receptor, and natural genetic variants in nutrient-sensing pathways are associated with increased human life span. Dietary restriction and reduced activity of nutrient-sensing pathways may thus slow aging by similar mechanisms, which have been conserved during evolution. We discuss these findings and their potential application to prevention of age-related disease and promotion of healthy aging in humans, and the challenge of possible negative side effects.

Luigi Fontana (Washington University School of Medicine/Istituto Superiore di Sanità;Division of Geriatrics and Nutritional Science/Division of Nutrition and Aging); Linda Partridge (University College London;3Institute of Healthy Aging, and G.E.E.); Valter Longo (University of Southern California;Andrus Gerontology Center and Department of Biological Sciences)

2010-04-16

71

Life-span studies of inhaled plutonium in beagle dogs  

SciTech Connect

In 1970 a life-span study with over 300 beagle dogs was begun to gain an understanding of long-term health effects resulting from respiratory tract intakes of plutonium and to derive risk estimates that might be applied to plutonium and other transuranic elements. Groups of beagle dogs were given single exposures to {sup 239}PuO{sub 2}, {sup 238}PuO{sub 2}, or {sup 239}Pu(NO{sub 3}){sub 4} to obtain graded levels of initial lung burdens ranging from 1 to 1800 Bq lung. The objective of this paper is to give you a progress report on the current life-span studies of inhaled plutonium in beagle dogs at the Pacific Northwest Laboratory. I will describe the biokinetics of inhaled plutonium in dogs and the resulting health effects. I will also mention some studies directed towards understanding the mechanism leading to these effects. Finally, I will discuss the current risk estimates derived from these studies and how they might relate to plutonium exposures in humans. 5 refs., 13 figs., 4 tabs.

Bair, W.J.

1990-04-01

72

Amino acid sources in the adult diet do not affect life span and fecundity in the fruit-feeding butterfly Bicyclus anynana  

PubMed Central

1. In tropical forests, the adults of many butterfly species feed on fruits rather than nectar from flowers and have long life spans. Rotting fruit and nectar differ from each other in many respects, including sources of amino acids and microbial life. If amino acids in the adult diet can be used for reproduction, this may have facilitated the evolution of extended life spans in this guild. 2. This issue was addressed by investigating effects of banana, yeast, and amino acids in the adult diet of the fruit-feeding butterfly Bicyclus anynana (Lepidoptera) on longevity and female reproductive output in two experiments. 3. Results showed that in the fruit-feeding butterfly B. anynana: (i) banana juice, but not sliced banana or added amino acids extend life span compared with a sugar solution of similar composition; (ii) compared with this sugar solution, other cohorts (banana juice-amino acid enriched) did not have significantly higher reproductive outputs; (iii) yeast does not represent a valuable source of nutrients; (iv) caloric restriction may cause decreased life span and rate of reproduction; and (v) increased rates of reproduction have a life span cost.

Molleman, Freerk; Ding, Jimin; Wang, Jane-Ling; Brakefield, Paul M.; Carey, James R.; Zwaan, Bas J.

2008-01-01

73

Female life span and fertility are increased by the ejaculates of preferred males.  

PubMed

In animals with internal fertilization, sperm competition among males can favor the evolution of male ejaculate traits that are detrimental to females. Female mating preferences, in contrast, often favor traits in males that are beneficial to females, yet little is known about the effect of these preferences on the evolution of male ejaculates. A necessary condition for female preferences to affect the evolution of male ejaculate characteristics is that females select mates based on a trait correlated with ejaculate quality. Previous work has shown that females of the variable field cricket, Gryllus lineaticeps, prefer males that produce calling songs containing faster and longer chirps. In this study, we tested the hypothesis that females receive more beneficial ejaculates from preferred males. Females were placed on either a high- or a reduced-nutrition diet then mated twice to a male of known song phenotype. Females received only sperm and seminal fluid from males during these matings. There was no effect of male song phenotype on any fitness component for females on the high-nutrition diet. Reduced-nutrition females mated to males that produced preferred song types, however, lived longer, produced more eggs, produced more fertile eggs, and had a higher proportion of their eggs fertilized than those mated to other males. The life-span benefit was positively associated with male chirp duration, and the reproductive benefits were positively associated with male chirp rate. We explored two possible mechanisms for the life span and reproductive benefits. First, a path analysis suggested that part of the effect of male chirp duration on female life span may have been indirect; females mated to males that produced longer chirps showed delayed oviposition, and females that delayed oviposition lived longer. Males that produce longer chirps may thus transfer fewer or less potent oviposition stimulants to females in their seminal fluid. Second, there was a positive correlation between male chirp rate and the number of sperm transferred to females. The fertility benefit may thus have resulted from females receiving more sperm from males that produce faster chirps. Finally, there was a negative phenotypic correlation between male chirp rate and chirp duration, suggesting that females may have to trade off the life span and reproduction benefits when selecting a mate. PMID:14575327

Wagner, William E; Harper, Christopher J

2003-09-01

74

Oxidative stress and the evolution of sex differences in life span and ageing in the decorated cricket, Gryllodes sigillatus.  

PubMed

The Free Radical Theory of Ageing (FRTA) predicts that oxidative stress, induced when levels of reactive oxygen species exceed the capacity of antioxidant defenses, causes ageing. Recently, it has also been argued that oxidative damage may mediate important life-history trade-offs. Here, we use inbred lines of the decorated cricket, Gryllodes sigillatus, to estimate the genetic (co)variance between age-dependent reproductive effort, life span, ageing, oxidative damage, and total antioxidant capacity within and between the sexes. The FRTA predicts that oxidative damage should accumulate with age and negatively correlate with life span. We find that protein oxidation is greater in the shorter lived sex (females) and negatively genetically correlated with life span in both sexes. However, oxidative damage did not accumulate with age in either sex. Previously we have shown antagonistic pleiotropy between the genes for early-life reproductive effort and ageing rate in both sexes, although this was stronger in females. In females, we find that elevated fecundity early in life is associated with greater protein oxidation later in life, which is in turn positively correlated with the rate of ageing. Our results provide mixed support for the FRTA but suggest that oxidative stress may mediate sex-specific life-history strategies in G. sigillatus. PMID:23461314

Archer, Catharine R; Sakaluk, Scott K; Selman, Colin; Royle, Nick J; Hunt, John

2012-10-10

75

Integrating the Life Course and Life-Span: Formulating Research Questions with Dual Points of Entry.  

ERIC Educational Resources Information Center

|Life-span research typically begins with personal characteristics, life-course research with social context and roles. Using both points of entry will encourage interdisciplinary work as well as the study of person-context interactions. (Contains 30 references.) (SK)|

Shanahan, Michael J.; Porfelli, Erik

2002-01-01

76

Impact of height and weight on life span.  

PubMed Central

The study was conducted to evaluate one aspect of the entropy theory of aging, which hypothesizes that aging is the result of increasing disorder within the body, and which predicts that increasing mass lowers life span. The first evaluation of the impact of human size on longevity or life span in 1978, which was based on data for decreased groups of athletes and famous people in the USA, suggested that shorter, lighter men live longer than their taller, heavier counterparts. In 1990, a study of 1679 decreased men and women from the general American population supported these findings. In the present study data on the height, weight, and age at death of 373 men were obtained from records at the Veterans Administration Medical Center, San Diego, CA, USA. Men of height 175.3 cm or less lived an average of 4.95 years longer than those of height over 175.3 cm, while men of height 170.2 cm or less lived 7.46 years longer than those of at least 182.9 cm. An analysis by weight difference revealed a 7.72-year greater longevity for men of weight 63.6 kg or less compared with those of 90.9 kg or more. This corroborates earlier evidence and contradicts the popular notion that taller people are healthier. While short stature due to malnutrition or illness is undesirable, our study suggests that feeding children for maximum growth and physical development may not add to and may indeed be harmful to their long-term health and longevity.

Samaras, T. T.; Storms, L. H.

1992-01-01

77

Quantitative and Molecular Genetic Analyses of Mutations Increasing Drosophila Life Span  

PubMed Central

Understanding the genetic and environmental factors that affect variation in life span and senescence is of major interest for human health and evolutionary biology. Multiple mechanisms affect longevity, many of which are conserved across species, but the genetic networks underlying each mechanism and cross-talk between networks are unknown. We report the results of a screen for mutations affecting Drosophila life span. One third of the 1,332 homozygous P–element insertion lines assessed had quantitative effects on life span; mutations reducing life span were twice as common as mutations increasing life span. We confirmed 58 mutations with increased longevity, only one of which is in a gene previously associated with life span. The effects of the mutations increasing life span were highly sex-specific, with a trend towards opposite effects in males and females. Mutations in the same gene were associated with both increased and decreased life span, depending on the location and orientation of the P–element insertion, and genetic background. We observed substantial—and sex-specific—epistasis among a sample of ten mutations with increased life span. All mutations increasing life span had at least one deleterious pleiotropic effect on stress resistance or general health, with different patterns of pleiotropy for males and females. Whole-genome transcript profiles of seven of the mutant lines and the wild type revealed 4,488 differentially expressed transcripts, 553 of which were common to four or more of the mutant lines, which include genes previously associated with life span and novel genes implicated by this study. Therefore longevity has a large mutational target size; genes affecting life span have variable allelic effects; alleles affecting life span exhibit antagonistic pleiotropy and form epistatic networks; and sex-specific mutational effects are ubiquitous. Comparison of transcript profiles of long-lived mutations and the control line reveals a transcriptional signature of increased life span.

Magwire, Michael M.; Yamamoto, Akihiko; Carbone, Mary Anna; Roshina, Natalia V.; Symonenko, Alexander V.; Pasyukova, Elena G.; Morozova, Tatiana V.; Mackay, Trudy F. C.

2010-01-01

78

Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline  

Microsoft Academic Search

Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recognition of multidirectionality in ontogenetic change, consideration of

Paul B. Baltes

1987-01-01

79

Theoretical Propositions of Life-Span Developmental Psychology: On the Dynamics Between Growth and Decline  

Microsoft Academic Search

Life-span developmental psychology involves the study of constancy and change in behavior throughout the life course. One aspect of life-span research has been the advancement of a more general, metatheoretical view on the nature of development. The family of theoretical perspectives associated with this metatheoretical view of life-span developmental psychology includes the recog- nition of multidirectionality in ontogenetic change, consideration

Paul B. Baltes

1987-01-01

80

How Long Will My Mouse Live? Machine Learning Approaches for Prediction of Mouse Life Span  

Microsoft Academic Search

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

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

2008-01-01

81

Close relationship between leaf life span and seedling relative growth rate in temperate hardwood species  

Microsoft Academic Search

The life span of resource-acquiring organs (leaves, shoots, fine roots) is closely associated with species successional position\\u000a and environmental resource availability. We examined to what extent leaf life span is related to inter- and intraspecific\\u000a variation in seedling relative growth rate (RGR). We examined relationships between relative growth rate in mass (RGRM) or height (RGRH) and leaf life span, together

Kenji Seiwa; Kihachiro Kikuzawa

2011-01-01

82

7 CFR 701.37 - Loss of control of the property during the practice life span.  

Code of Federal Regulations, 2013 CFR

...false Loss of control of the property during the practice life span...AGRICULTURE AGRICULTURAL CONSERVATION PROGRAM EMERGENCY CONSERVATION PROGRAM, EMERGENCY FOREST...37 Loss of control of the property during the practice life...

2013-01-01

83

Skill Learning as a Concept in Life-Span Developmental Psychology: An Action Theoretic Analysis  

Microsoft Academic Search

An action theoretic account of skill learning and skill use is offered as a useful heuristic for life-span developmental psychology. It is suggested that analyses of the tasks confronting an individual and of the structure of action, as well as of the interplay of these two, have implications for the understanding of development across the life span. In particular, these

Michael Frese; Judith Stewart

1984-01-01

84

Adopting a Life-Span Perspective on the First School Transition  

Microsoft Academic Search

This article discusses the implications of life-span developmental theory for the design and implementation of an intervention into the first school transition, beginning with organized prekindergarten and ending with fifth grade. Orville Gilbert Brim's contributions to the life-span perspective are highlighted with regard to his own scholarship and his generative contributions to the field as a foundation leader. These include

David L. Featherman; Deborah A. Phillips

2009-01-01

85

High Osmolarity Extends Life Span in Saccharomyces cerevisiae by a Mechanism Related to Calorie Restriction  

Microsoft Academic Search

Calorie restriction (CR) extends life span in many different organisms, including mammals. We describe here a novel pathway that extends the life span of Saccharomyces cerevisiae mother cells but does not involve a reduction in caloric content of the media, i.e., there is growth of yeast cells in the presence of a high concentration of external osmolytes. Like CR, this

Matt Kaeberlein; Alex A. Andalis; Gerald R. Fink; Leonard Guarente

2002-01-01

86

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

ERIC Educational Resources Information Center

|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…

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

2013-01-01

87

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

PubMed

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. PMID:1890293

Lesser, J A; Kunkel, S R

1991-09-01

88

The Rate of Source Memory Decline across the Adult Life Span  

ERIC Educational Resources Information Center

|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…

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

89

High sexual signalling rates of young individuals predict extended life span in male Mediterranean fruit flies  

Microsoft Academic Search

In a laboratory study, we monitored the lifetime sexual signalling (advertisement) of wild male Mediterranean fruit flies, and we tested the hypothesis that high lifetime intensity of sexual signalling indicates high survival probabilities. Almost all males exhibited signalling and individual signalling rates were highly variable from the beginning of the adults’ maturity and throughout their life span (average life span

Nikos T. Papadopoulos; Byron I. Katsoyannos; Nikos A. Kouloussis; James R. Carey; Hans-Georg Müller; Ying Zhang

2004-01-01

90

Effects of X-rays on Metamorphosis and Adult Life Span of Flour Beetles  

Microsoft Academic Search

IT has been shown that the adult life span is reduced when young mice are irradiated with X-rays1 and when the parasitoid wasp, Habrobracon, is irradiated during the immature stages of its life cycle2-4. Lamb and Maynard Smith5 recently reviewed the reduction of insect life spans by radiation and postulated that radiations shorten life by inducing mutations in somatic cells.

Howard E. Erdman

1966-01-01

91

Mechanisms of Life Span Extension by Rapamycin in the Fruit Fly Drosophila melanogaster  

PubMed Central

Summary The target of rapamycin (TOR) pathway is a major nutrient-sensing pathway that, when genetically downregulated, increases life span in evolutionarily diverse organisms including mammals. The central component of this pathway, TOR kinase, is the target of the inhibitory drug rapamycin, a highly specific and well-described drug approved for human use. We show here that feeding rapamycin to adult Drosophila produces the life span extension seen in some TOR mutants. Increase in life span by rapamycin was associated with increased resistance to both starvation and paraquat. Analysis of the underlying mechanisms revealed that rapamycin increased longevity specifically through the TORC1 branch of the TOR pathway, through alterations to both autophagy and translation. Rapamycin could increase life span of weak insulin/Igf signaling (IIS) pathway mutants and of flies with life span maximized by dietary restriction, indicating additional mechanisms.

Bjedov, Ivana; Toivonen, Janne M.; Kerr, Fiona; Slack, Cathy; Jacobson, Jake; Foley, Andrea; Partridge, Linda

2010-01-01

92

Submandibular salivary glands: influence on growth rate and life span in mice.  

PubMed

Submandibular glands accumulate a variety of growth factors, especially in male mice. Surgical excision of these glands (sialoadenectomy) results in alterations in several organs and systems including the liver, skin and reproductive system. We studied the life-long consequences of sialoadenectomy in male mice. Animals were operated at the age of 10 weeks. Thereafter, body weight and food and water intake were controlled until death. Few weeks after surgery, body weight was lower in sialoadenectomized than in control mice. The difference remained stable until the age of 80 weeks. In spite of the lower body weight, food intake was higher in sialoadenectomized mice than in controls. The first death of sialoadenectomized mice occurred 10 weeks earlier than that of the first control, and the initial death rate in sialoadenectomized mice was almost twice the rate in controls. After 100 weeks of life, the death rate increased in control mice, but suddenly decreased in sialoadenectomized mice. The consequence was that the mean life span of the last 25% surviving animals was 10 weeks longer in sialoadenectomized than in control mice. Autopsy examination suggests that the effect of sialoadenectomy on death rate may be the consequence of a contrasting effect on tumour growth. Our results indicate that submandibular glands, or rather the factors derived from these glands, have contrasting roles in tumour growth. At early ages they may be survival factors and protect tissues, whereas at later ages they may stimulate the growth of transformed cells. PMID:21191684

Ramírez, Ignasi; Soley, Maria

2010-12-31

93

Personality and Obesity Across the Adult Life Span  

Microsoft Academic Search

Personality traits contribute to health outcomes, in part through their association with major controllable risk factors, such as obesity. Body weight, in turn, reflects our behaviors and lifestyle and contributes to the way we perceive ourselves and others. In this study, the authors use data from a large (N = 1,988) longitudinal study that spanned more than 50 years to

Angelina R. Sutin; Luigi Ferrucci; Alan B. Zonderman; Antonio Terracciano

2011-01-01

94

Life history theory and human reproductive behavior  

Microsoft Academic Search

The purpose of this article is to develop a model of life history theory that incorporates environmental influences, contextual\\u000a influences, and heritable variation. I argue that physically or psychologically stressful environments delay maturation and\\u000a the onset of reproductive competence. The social context is also important, and here I concentrate on the opportunity for\\u000a upward social mobility as a contextual influence

Kevin MacDonald; California State

1997-01-01

95

THE LIFE SPAN OF THE COMMON TERN (Stepea hip undo)  

Microsoft Academic Search

in the area in 1940 as compared with at least three in 1941, probably correlated with the earlier season. This illustrates how progress of spring may influence the amount of reproduction since apparently a second brood is more likely to be attempted at this latitude when the first brood is completed fairly early in June. LITERATURE CITED BUTTS, WmBER K.

OLIVER L. AUSTIN

96

Fecundity and life span in transgenic Drosophila melanogaster overexpressing hsp70  

Microsoft Academic Search

In the present study, we investigated the effect of hsp70 over expression on some life history components in transgenic fruit\\u000a flies. We measured life span in mated flies and fecundity in flies subjected or not subjected to a heat shock inducing hsp70.\\u000a Heat shock increased life span of the parental line, but not of the transgenic lines. Genetic manipulation of

Nadège Minois; Sofia Vaynberg

2002-01-01

97

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

PubMed

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

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

2010-05-01

98

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

PubMed Central

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.

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

2010-01-01

99

Transplantation of young ovaries to old mice increased life span in transplant recipients.  

PubMed

Previously we reported that prepubertally ovariectomized mice that received young transplanted ovaries at a postreproductive age showed a 40% increase in life expectancy. To study this phenomenon in greater detail, 11-month-old ovariectomized and ovary-intact CBA/J mice underwent ovarian transplantation with 60-day-old ovaries or a sham surgery. Results from observations on transplant recipients in the current study extended our previous results. Whereas intact control mice lived an average of 726 days, transplant recipients lived an average of 770 days (i.e., 780 days for intact recipients and 757 days for ovariectomized recipients). If intact recipients had ceased reproductive cycling by the time of transplant, we observed a further increase in mean life span to 811 days. These results demonstrate that young ovaries enhanced longevity when transplanted to old mice and that ovarian status, examined by means of ovariectomy and ovarian transplantation, clearly influenced the potential of young transplanted ovaries to positively impact longevity. PMID:19776215

Mason, Jeffrey B; Cargill, Shelley L; Anderson, Gary B; Carey, James R

2009-09-23

100

Increased expression of Drosophila Sir2 extends life span in a dose-dependent manner.  

PubMed

Sir2, a member of the sirtuin family of protein acylases, deacetylates lysine residues within many proteins and is associated with lifespan extension in a variety of model organisms. Recent studies have questioned the positive effects of Sir2 on lifespan inDrosophila. Several studies have shown that increased expression of the Drosophila Sir2 homolog (dSir2) extends life span while other studies have reported no effect on life span or suggested that increased dSir2 expression was cytotoxic. To attempt to reconcile the differences in these observed effects of dSir2 on Drosophila life span, we hypothesized that a critical level of dSir2 may be necessary to mediate life span extension. Using approaches that allow us to titrate dSir2 expression, we describe here a strong dose-dependent effect of dSir2 on life span. Using the two transgenic dSir2 lines that were reported not to extend life span, we are able to show significant life span extension when dSir2 expression is induced between 2 and 5-fold. However, higher levels decrease life span and can induce cellular toxicity, manifested by increased expression of the JNK-signaling molecule Puc phosphatase and induction of dnaJ-H. Our results help to resolve the apparently conflicting reports by demonstrating that the effects of increased dSir2 expression on life span in Drosophila are dependent upon dSir2 dosage. PMID:24036492

Whitaker, Rachel; Faulkner, Shakeela; Miyokawa, Reika; Burhenn, Lucas; Henriksen, Mark; Wood, Jason G; Helfand, Stephen L

2013-09-01

101

Reproduction: life cycle, larvae and larviculture.  

PubMed

Nephrops norvegicus represents a very valuable fishery across Europe, and the species possesses a relatively complex life cycle and reproductive biology across spatial and temporal scales. Insights into embryonic and larval biology, and associated abiotic and biotic factors that influence recruitment, are important since this will affect population and species success. Much of the fishery, and indeed scientific sampling, is reliant on trawling, which is likely to cause direct and indirect stresses on adults and developing embryos. We have collated evidence, including that garnered from laboratory studies, to assess the likely effects on reproduction and population. Using know-how from hatchery operations in similar species such as Homarus sp., we also seek to optimise larviculture that could be commercialised to create a hatchery and thus assist stock remediation. This review chapter is therefore divided into three sections: (1) general N. norvegicus reproductive biology, (2) life cycle and larval biology and (3) a comprehensive review of all rearing attempts for this species to date, including a likely way forward for pilot scale and hence commercial restocking operations. PMID:23668591

Powell, Adam; Eriksson, Susanne P

2013-01-01

102

Catatonia in autism: implications across the life span  

Microsoft Academic Search

Background  There is increasing evidence that catatonia is an important source of impairment in adolescents and adults with autism.\\u000a \\u000a \\u000a \\u000a Aim  Review of the evaluation, diagnosis, differential diagnosis, and treatment of catatonia in autism.\\u000a \\u000a \\u000a \\u000a Method  Presentation and discussion of a case-vignette spanning early childhood to adulthood.\\u000a \\u000a \\u000a \\u000a Results  Autistic and catatonic symptoms overlap, yet catatonia is diagnosable in about one of seven adolescents and young adults

Angelina Kakooza-Mwesige; Lee E. Wachtel; Dirk M. Dhossche

2008-01-01

103

Self-Determination across the Life Span: Issues and Gaps  

ERIC Educational Resources Information Center

|This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that are…

Heller, Tamar; Schindler, Abigail; Palmer, Susan B.; Wehmeyer, Michael L.; Parent, Wendy; Jenson, Ronda; Abery, Brian H.; Geringer, Wendy; Bacon, Ansley; O'Hara, David M.

2011-01-01

104

Self-Determination across the Life Span: Issues and Gaps  

ERIC Educational Resources Information Center

This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that are…

Heller, Tamar; Schindler, Abigail; Palmer, Susan B.; Wehmeyer, Michael L.; Parent, Wendy; Jenson, Ronda; Abery, Brian H.; Geringer, Wendy; Bacon, Ansley; O'Hara, David M.

2011-01-01

105

Self-Determination across the Life Span: Issues and Gaps  

Microsoft Academic Search

This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that are relevant during several age ranges. A lifespan approach to self-determination takes into

Tamar Heller; Abigail Schindler; Susan B. Palmer; Michael L. Wehmeyer; Wendy Parent; Ronda Jenson; Brian H. Abery; Wendy Geringer; Ansley Bacon; David M. OHara

2011-01-01

106

Effect of BCL2 down-regulation on cellular life span  

Microsoft Academic Search

Reactive oxygen species (ROS) are toxic for cells. BCL-2 is known as the anti-death protein and acts as an antioxidant. When\\u000a theBCL-2 level of normal fibroblasts was suppressed by antisense bcl-2oligodeoxynucleotide or antisense bcl-2 RNA expression, the life span of the culture was shortened by about 11 population doublings(approx. 15% of the total life\\u000a span) in comparison to the control

Tsutomu Kumazaki; Masao Sasaki; Masahiko Nishiyama; Yasuhiro Teranishi; Hiroshi Sumida; Youji Mitsui

2002-01-01

107

Copper supplementation increases yeast life span under conditions requiring respiratory metabolism  

Microsoft Academic Search

To further exploit yeast as a model for cellular aging we have modified the replicative life span assay to force respiration, by replacing glucose with the non-fermentable carbon source glycerol. The growth rates of several different strains varied greatly, with doubling times ranging from 2.7 to 7h. Life spans of all strains were lower on media containing glycerol than on

Paul A. Kirchman; Gabriela Botta

2007-01-01

108

Extension of Life-Span with Superoxide Dismutase\\/Catalase Mimetics  

Microsoft Academic Search

We tested the theory that reactive oxygen species cause aging. We augmented the natural antioxidant systems of Caenorhabditis elegans with small synthetic superoxide dismutase\\/catalase mimetics. Treatment of wild-type worms increased their mean life-span by a mean of 44 percent, and treatment of prematurely aging worms resulted in normalization of their life-span (a 67 percent increase). It appears that oxidative stress

Simon Melov; Joanne Ravenscroft; Sarwatt Malik; Matt S. Gill; David W. Walker; Peter E. Clayton; Douglas C. Wallace; Bernard Malfroy; Susan R. Doctrow; Gordon J. Lithgow

2000-01-01

109

Disentangling environmental effects on adult life span in a butterfly across the metamorphic boundary.  

PubMed

Life span is a central life history trait often showing tremendous variation within populations. Much of this variation can be attributed to environmental factors. In holometabolous insects life stages differ strikingly in physiology and energetic demands, and environmental variation before and after metamorphosis may not necessarily yield identical responses. In this study, we adopted a full-factorial experimental design with two larval and two adult temperatures as well as two larval and three adult feeding treatments (n(total)=1151). Identical temperatures yielded qualitatively different results depending on the developmental stage. While the lower compared to the higher developmental temperature slightly reduced adult life span, a lower adult temperature substantially increased life span. Food stress in the larval stage slightly reduced life span, as did food stress during the adult stage. Females lived generally longer than males. All factors investigated were involved in interactions with other factors, both within and across life stages. For instance, the qualitative impact of larval food stress depended on adult feeding treatment and adult temperature. Our results suggest that much insight into the causes of variation in life span is to be gained by explicitly considering environmental impacts across developmental stages and potential interactions among different environmental factors. PMID:19836442

Bauerfeind, Stephanie S; Perlick, Jana E C; Fischer, Klaus

2009-10-28

110

Glucose Shortens the Life Span of C. elegans by Downregulating DAF-16\\/FOXO Activity and Aquaporin Gene Expression  

Microsoft Academic Search

SUMMARY Many studies have addressed the effect of dietary glycemic index on obesity and diabetes, but little is known about its effect on life span itself. We found that adding a small amount of glucose to the medium (2%) shortened the life span of C. elegans by inhibit- ing the activities of life span-extending transcription factors that are also inhibited

Seung-Jae Lee; Coleen T. Murphy; Cynthia Kenyon

2009-01-01

111

History, Narrative, and Life-Span Developmental Knowledge  

Microsoft Academic Search

The problem of finding continuity across the life course can be tied in part to a theoretical perspective which looks essentially forward in time. It can, however, be significantly minimized within a framework that is more genuinely historical, one that looks back over the flow of events in an attempt to understand and explain their possible connections. That this involves

Mark Freeman

1984-01-01

112

Personality and self-esteem development across the life span  

Microsoft Academic Search

Over the past few decades, there has been an explosion of longitudinal research on the consistency of personality and related constructs such as self-esteem. This plethora of studies has provided suKcient evidence to move researchers toward consensus about the degree to which personality characteristics change over the life course. The emerging story, based on an accumulating body of empirical research,

Kali H. Trzesniewski; Richard W. Robins; Brent W. Roberts; Avshalom Caspi

2003-01-01

113

Conceptions of Gay Male Life-Span Development  

Microsoft Academic Search

Four of Erikson's eight psychosocial crises were used in this qualitative, exploratory study as an organizing framework. Using a semi-structured questionnaire, seven men were interviewed with the goal of understanding how they have navigated Erikson's life stages. Significant results included: an early sense of being different and a period of time between “coming out to self” and “coming out to

David Roseborough

2004-01-01

114

Regret and Quality of Life Across the Adult Life Span: The Influence of Disengagement and Available Future Goals  

Microsoft Academic Search

Two studies examined the associations between life regrets and indicators of quality of life across the adult life span. Given that opportunities to undo regrets decline with age, regret intensity was expected to be inversely associated with subjective well-being and health among older adults. In addition, the research explored protective factors that have the potential to reduce older adults' regret

Carsten Wrosch; Isabelle Bauer; Michael F. Scheier

2005-01-01

115

Nutrition research to affect food and a healthy life span.  

PubMed

Proper nutrition offers one of the most effective and least costly ways to decrease the burden of many diseases and their associated risk factors, including obesity. Nutrition research holds the key to increasing our understanding of the causes of obesity and its related comorbidities and thus holds promise to markedly influence global health and economies. After outreach to 75 thought leaders, the American Society for Nutrition (ASN) convened a Working Group to identify the nutrition research needs whose advancement will have the greatest projected impact on the future health and well-being of global populations. ASN's Nutrition Research Needs focus on the following high priority areas: 1) variability in individual responses to diet and foods; 2) healthy growth, development, and reproduction; 3) health maintenance; 4) medical management; 5) nutrition-related behaviors; and 6) food supply/environment. ASN hopes the Nutrition Research Needs will prompt collaboration among scientists across all disciplines to advance this challenging research agenda given the high potential for translation and impact on public health. Furthermore, ASN hopes the findings from the Nutrition Research Needs will stimulate the development and adoption of new and innovative strategies that can be applied toward the prevention and treatment of nutrition-related diseases. The multidisciplinary nature of nutrition research requires stakeholders with differing areas of expertise to collaborate on multifaceted approaches to establish the evidence-based nutrition guidance and policies that will lead to better health for the global population. In addition to the identified research needs, ASN also identified 5 tools that are critical to the advancement of the Nutrition Research Needs: 1) omics, 2) bioinformatics, 3) databases, 4) biomarkers, and 5) cost-effectiveness analysis. PMID:23784071

Ohlhorst, Sarah D; Russell, Robert; Bier, Dennis; Klurfeld, David M; Li, Zhaoping; Mein, Jonathan R; Milner, John; Ross, A Catharine; Stover, Patrick; Konopka, Emily

2013-06-19

116

Nutrition research to affect food and a healthy life span.  

PubMed

Proper nutrition offers one of the most effective and least costly ways to decrease the burden of many diseases and their associated risk factors, including obesity. Nutrition research holds the key to increasing our understanding of the causes of obesity and its related comorbidities and thus holds promise to markedly influence global health and economies. After outreach to 75 thought leaders, the American Society for Nutrition (ASN) convened a Working Group to identify the nutrition research needs whose advancement will have the greatest projected impact on the future health and well-being of global populations. ASN's Nutrition Research Needs focus on the following high priority areas: 1) variability in individual responses to diet and foods; 2) healthy growth, development, and reproduction; 3) health maintenance; 4) medical management; 5) nutrition-related behaviors; and 6) food supply/environment. ASN hopes the Nutrition Research Needs will prompt collaboration among scientists across all disciplines to advance this challenging research agenda given the high potential for translation and impact on public health. Furthermore, ASN hopes the findings from the Nutrition Research Needs will stimulate the development and adoption of new and innovative strategies that can be applied toward the prevention and treatment of nutrition-related diseases. The multidisciplinary nature of nutrition research requires stakeholders with differing areas of expertise to collaborate on multifaceted approaches to establish the evidence-based nutrition guidance and policies that will lead to better health for the global population. In addition to the identified research needs, ASN also identified 5 tools that are critical to the advancement of the Nutrition Research Needs: 1) omics, 2) bioinformatics, 3) databases, 4) biomarkers, and 5) cost-effectiveness analysis. PMID:23783290

Ohlhorst, Sarah D; Russell, Robert; Bier, Dennis; Klurfeld, David M; Li, Zhaoping; Mein, Jonathan R; Milner, John; Ross, A Catharine; Stover, Patrick; Konopka, Emily

2013-08-01

117

Life Span Extension and Neuronal Cell Protection by Drosophila Nicotinamidase*S?  

PubMed Central

The life span of model organisms can be modulated by environmental conditions that influence cellular metabolism, oxidation, or DNA integrity. The yeast nicotinamidase gene pnc1 was identified as a key transcriptional target and mediator of calorie restriction and stress-induced life span extension. PNC1 is thought to exert its effect on yeast life span by modulating cellular nicotinamide and NAD levels, resulting in increased activity of Sir2 family class III histone deacetylases. In Caenorhabditis elegans, knockdown of a pnc1 homolog was shown recently to shorten the worm life span, whereas its overexpression increased survival under conditions of oxidative stress. The function and regulation of nicotinamidases in higher organisms has not been determined. Here, we report the identification and biochemical characterization of the Drosophila nicotinamidase, D-NAAM, and demonstrate that its overexpression significantly increases median and maximal fly life span. The life span extension was reversed in Sir2 mutant flies, suggesting Sir2 dependence. Testing for physiological effectors of D-NAAM in Drosophila S2 cells, we identified oxidative stress as a primary regulator, both at the transcription level and protein activity. In contrast to the yeast model, stress factors such as high osmolarity and heat shock, calorie restriction, or inhibitors of TOR and phosphatidylinositol 3-kinase pathways do not appear to regulate D-NAAM in S2 cells. Interestingly, the expression of D-NAAM in human neuronal cells conferred protection from oxidative stress-induced cell death in a sirtuin-dependent manner. Together, our findings establish a life span extending the ability of nicotinamidase in flies and offer a role for nicotinamide-modulating genes in oxidative stress regulated pathways influencing longevity and neuronal cell survival.

Balan, Vitaly; Miller, Gregory S.; Kaplun, Ludmila; Balan, Karina; Chong, Zhao-Zhong; Li, Faqi; Kaplun, Alexander; VanBerkum, Mark F. A.; Arking, Robert; Freeman, D. Carl; Maiese, Kenneth; Tzivion, Guri

2008-01-01

118

'Willpower' over the life span: decomposing self-regulation  

PubMed Central

In the 1960s, Mischel and colleagues developed a simple ‘marshmallow test’ to measure preschoolers’ ability to delay gratification. In numerous follow-up studies over 40?years, this ‘test’ proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on ‘cognitive control’ mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of ‘willpower’ and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued.

Ayduk, Ozlem; Berman, Marc G.; Casey, B. J.; Gotlib, Ian H.; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L.; Zayas, Vivian

2011-01-01

119

'Willpower' over the life span: decomposing self-regulation.  

PubMed

In the 1960s, Mischel and colleagues developed a simple 'marshmallow test' to measure preschoolers' ability to delay gratification. In numerous follow-up studies over 40?years, this 'test' proved to have surprisingly significant predictive validity for consequential social, cognitive and mental health outcomes over the life course. In this article, we review key findings from the longitudinal work and from earlier delay-of-gratification experiments examining the cognitive appraisal and attention control strategies that underlie this ability. Further, we outline a set of hypotheses that emerge from the intersection of these findings with research on 'cognitive control' mechanisms and their neural bases. We discuss implications of these hypotheses for decomposing the phenomena of 'willpower' and the lifelong individual differences in self-regulatory ability that were identified in the earlier research and that are currently being pursued. PMID:20855294

Mischel, Walter; Ayduk, Ozlem; Berman, Marc G; Casey, B J; Gotlib, Ian H; Jonides, John; Kross, Ethan; Teslovich, Theresa; Wilson, Nicole L; Zayas, Vivian; Shoda, Yuichi

2010-09-19

120

Worldwide Variation in Life-Span Sexual Dimorphism and Sex-Specific Environmental Mortality Rates  

Microsoft Academic Search

In all human populations mean life span of women generally exceeds that of men, but the extent of this sexual dimorphism varies across different regions of the world. Our purpose here is to study, using global demographic and environmental data, the general tendency of this variation and local deviations from it. We used data on male and female life history

Anatoly T. Teriokhin; Elena V. Budilova; Frederic Thomas; Jean-Francois Guegan

2004-01-01

121

Worldwide Variation in Life-Span Sexual Dimorphism and Sex-Specific Environmental Mortality Rates  

Microsoft Academic Search

In all human populations mean life span of women generally exceeds that of men, but the extent of this sexual dimorphism varies across different regions of the world. Our purpose here is to study, using global demographic and environmental data, the general tendency of this variation and local deviations from it. We used data on male and female life history

Anatoly T. Teriokhin; Elena V. Budilovo; Frederic Thomas; Jean-Francois Guegan

2011-01-01

122

Meal-Timing, Circadian Rhythms and Life Span of Mice1  

Microsoft Academic Search

The possibility that circadian rhythm alteration may contribute to the life-prolonging effect of food restriction was investigated in female CD2Fi mice housed in a room with a 12-h span of fluorescent lighting daily. A control group was allowed to feed ad libitum throughout life while three other groups began lifelong restriction to about 75 % of ad libitum intake when

WALTER NELSON; ANDFRANZ HALBERG

123

Sexuality and haemophilia: connections across the life-span.  

PubMed

A broad overview of sexuality issues and needs as they relate to haemophilia are presented. Venturing well beyond 'safer sex', sexuality is defined here to encompass physical, emotional, social, interpersonal, moral, and cultural aspects. From this perspective, sexuality extends beyond behaviour and includes a person's thoughts, feelings, nature, and identity. As a means of experiencing intimacy, sexuality is a significant factor in achieving quality of life with chronic illness. Its impact in haemophilia is influenced by different stages of physical and psychosexual development, misconceptions about sexuality, and unique concerns for this group, including joint disability, human immunodeficiency virus, medication side-effects, and other complications. This paper explores the interconnections of sexuality with haemophilia, with a focus on the roles that haemophilia care providers can play in addressing these issues. A biopsychosocial model of aspects and interrelationships regarding sexuality and haemophilia is proposed for use in understanding individuals and planning care approaches. The PLISSIT model is offered to guide counselling about sexuality on different levels of complexity. Sample strategies for initiating discussion, communicating about sex, and developing goals and interventions are presented. PMID:12010433

Parish, K L

2002-05-01

124

Life span effects of lexical factors on oral naming.  

PubMed

This study investigated how lexical access in naming tasks (picture naming, naming to open-ended sentences, and naming to category exemplars) might be influenced by different lexical factors during adolescence and adulthood. Participants included 1075 individuals, ranging in age from 12 to 83 years. Lexical factors examined included word frequency and familiarity, age of acquisition, neighborhood density, and phonotactic probability. As expected, each of these factors influenced lexical access, and there was a general trend towards less accurate naming with age. More interestingly, word frequency and neighborhood density both showed larger effects for adolescents than for adults, but then showed constant effects on lexical access throughout adulthood. Phonotactic probability showed constant effects across the lifespan. Effects of word familiarity and age of acquisition interacted with age in adulthood; lexical access of older adults was more greatly affected by a word's familiarity and age of acquisition than was the lexical access of younger adults. These lexical factors impact on adult naming so that words that were learned later in life and which are judged to be less familiar are more difficult to retrieve then their counterparts (words learned earlier and judged to be more familiar) as individuals age. This suggests that age of acquisition and familiarity may play a protective role in adult naming. In contrast, word frequency and form-based properties of words appear to have similar effects throughout adulthood. Implications of these findings for theories of aging and for models of lexical access are discussed. PMID:16411502

Newman, Rochelle S; German, Diane J

2005-01-01

125

Life-span adjustment of children to their parents' divorce.  

PubMed

Children who experience parental divorce, compared with children in intact two-parent families, exhibit more conduct problems, more symptoms of psychological maladjustment, lower academic achievement, more social difficulties, and poorer self-concepts. Similarly, adults who experienced parental divorce as children, compared with adults raised in continuously intact two-parent families, score lower on a variety of indicators of psychological, interpersonal, and socioeconomic well-being. However, the overall group differences between offspring from divorced and intact families are small, with considerable diversity existing in children's reactions to divorce. Children's adjustment to divorce depends on several factors, including the amount and quality of contact with noncustodial parents, the custodial parents' psychological adjustment and parenting skills, the level of interparental conflict that precedes and follows divorce, the degree of economic hardship to which children are exposed, and the number of stressful life events that accompany and follow divorce. These factors can be used as guides to assess the probable impact of various legal and therapeutic interventions to improve the well-being of children of divorce. PMID:7922276

Amato, P R

1994-01-01

126

Decreased energy metabolism extends life span in Caenorhabditis elegans without reducing oxidative damage.  

PubMed

On the basis of the free radical and rate of living theories of aging, it has been proposed that decreased metabolism leads to increased longevity through a decreased production of reactive oxygen species (ROS). In this article, we examine the relationship between mitochondrial energy metabolism and life span by using the Clk mutants in Caenorhabditis elegans. Clk mutants are characterized by slow physiologic rates, delayed development, and increased life span. This phenotype suggests that increased life span may be achieved by decreasing energy expenditure. To test this hypothesis, we identified six novel Clk mutants in a screen for worms that have slow defecation and slow development and that can be maternally rescued. Interestingly, all 11 Clk mutants have increased life span despite the fact that slow physiologic rates were used as the only screening criterion. Although mitochondrial function is decreased in the Clk mutants, ATP levels are normal or increased, suggesting decreased energy utilization. To determine whether the longevity of the Clk mutants results from decreased production of ROS, we examined sensitivity to oxidative stress and oxidative damage. We found no evidence for systematically increased resistance to oxidative stress or decreased oxidative damage in the Clk mutants despite normal or elevated levels of superoxide dismutases. Overall, our findings suggest that decreased energy metabolism can lead to increased life span without decreased production of ROS. PMID:20382831

Van Raamsdonk, Jeremy Michael; Meng, Yan; Camp, Darius; Yang, Wen; Jia, Xihua; Bénard, Claire; Hekimi, Siegfried

2010-04-09

127

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

PubMed

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 ?-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 ?-6 PUFAs. Supplementing C. elegans culture media with these ?-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 ?-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 ?-6 PUFAs. We propose that the salubrious effects of dietary supplementation with ?-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

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

2013-02-07

128

Longevity in space; experiment on the life span of Paramecium cell clone in space  

NASA Astrophysics Data System (ADS)

Life span is the most interesting and also the most important biologically relevant time to be investigated on the space station. As a model experiment, we proposed an investigation to assess the life span of clone generation of the ciliate Paramecium. In space, clone generation will be artificially started by conjugation or autogamy, and the life span of the cell populations in different gravitational fields (microgravity and onboard 1 × g control) will be precisely assessed in terms of fission age as compared with the clock time. In order to perform the space experiment including long-lasting culture and continuous measurement of cell division, we tested the methods of cell culture and of cell-density measurement, which will be available in closed environments under microgravity. The basic design of experimental hardware and a preliminary result of the cultivation procedure are described.

Mogami, Y.; Tokunaga, N.; Baba, S. A.

1999-01-01

129

Leaf Life Span Plasticity in Tropical Seedlings Grown under Contrasting Light Regimes  

PubMed Central

• Background and Aims The phenotypic plasticity of leaf life span in response to low resource conditions has a potentially large impact on the plant carbon budget, notably in evergreen species not subject to seasonal leaf shedding, but has rarely been well documented. This study evaluates the plasticity of leaf longevity, in terms of its quantitative importance to the plant carbon balance under limiting light. • Methods Seedlings of four tropical tree species with contrasting light requirements (Alstonia scholaris, Hevea brasiliensis, Durio zibethinus and Lansium domesticum) were grown under three light regimes (full sunlight, 45 % sunlight and 12 % sunlight). Their leaf dynamics were monitored over 18 months. • Results All species showed a considerable level of plasticity with regard to leaf life span: over the range of light levels explored, the ratio of the range to the mean value of life span varied from 29 %, for the least plastic species, to 84 %, for the most. The common trend was for leaf life span to increase with decreasing light intensity. The plasticity apparent in leaf life span was similar in magnitude to the plasticity observed in specific leaf area and photosynthetic rate, implying that it has a significant impact on carbon gain efficiency when plants acclimate to different light regimes. In all species, median survival time was negatively correlated with leaf photosynthetic capacity (or its proxy, the nitrogen content per unit area) and leaf emergence rate. • Conclusions Longer leaf life spans under low light are likely to be a consequence of slower ageing as a result of a slower photosynthetic metabolism.

VINCENT, GREGOIRE

2006-01-01

130

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

PubMed Central

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.

Mata, Rui; Wilke, Andreas; Czienskowski, Uwe

2013-01-01

131

Thioredoxin 1 Overexpression Extends Mainly the Earlier Part of Life Span in Mice  

PubMed Central

We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)+/0]. The Tg(TRX1)+/0 mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)+/0 mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)+/0 mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)+/0 mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)+/0 mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice.

Perez, Viviana I.; Cortez, Lisa A.; Lew, Christie M.; Rodriguez, Marisela; Webb, Celeste R.; Van Remmen, Holly; Chaudhuri, Asish; Qi, Wenbo; Lee, Shuko; Bokov, Alex; Fok, Wilson; Jones, Dean; Richardson, Arlan; Yodoi, Junji; Zhang, Yiqiang; Tominaga, Kaoru; Hubbard, Gene B.

2011-01-01

132

Evolutionary analysis of life span, competition, and adaptive radiation, motivated by the Pacific rockfishes (Sebastes).  

PubMed

The Pacific rockfishes (Sebastes spp) are remarkable for both their diversity (on the order of 100 species) and range of maximum life span ( approximately 10 years for Calico rockfish to approximately 200 years for Rougheye rockfish). We describe the natural history and patterns of diversity and life span in these species and then use independent contrasts to explore correlates of these. When phylogenetic history is taken into account, maximum life span is explained by age at maturity, size at maturity, and the interaction of these two. We introduce a life-history model that allows insight into the origin of these correlations. We then describe a variety of mechanisms that may increase lifepans and diversity. These include fluctuating environments (in which organisms basically have to "wait out" bad periods to reproduce successfully), diversity, and longevity inspired by interspecific competition and physiological complexity in growth and accumulation of cellular damage. All of the results point toward the importance of flat or "indifferent" fitness surfaces as a key element in the evolution of diversity. We conclude that further development of the theory of flat or indifferent fitness surfaces as applied to diversity and life span is clearly warranted. PMID:17492972

Mangel, Marc; Kindsvater, Holly K; Bonsall, Michael B

2007-05-01

133

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

PubMed

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. PMID:24082105

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

2013-09-30

134

Cytoplasmic influence on the expression of nuclear genes affecting life span in Drosophila melanogaster  

Microsoft Academic Search

In earlier studies we have found that the difference between short and long life spans of two inbred strains of Drosophila melanogaster is controlled by nuclear major genes. The present study has revealed a cytoplasmic factor that influences the expression of the nuclear longevity genes. The factor shows a typical maternal inheritance and is considered to be an extranuclear gene,

Isamu Yonemura; Tomio Motoyama; Hayato Hasekura; Barry Boettcher

1991-01-01

135

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

ERIC Educational Resources Information Center

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…

Dodd, Helen F.; Porter, Melanie A.

2009-01-01

136

Age, growth and size interact with stress to determine life span and mortality.  

PubMed

Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations; rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful. PMID:22664575

Roach, Deborah Ann

2012-06-01

137

Cancer risk among atomic bomb survivors. The RERF Life Span Study. Radiation Effects Research Foundation  

Microsoft Academic Search

This article summarizes the risk of cancer among the survivors of the atomic bombing of Hiroshima and Nagasaki. We focus primarily on the risk of death from cancer among individuals in the Life Span Study sample of the Radiation Effects Research Foundation from 1950 through 1985 based on recently revised dosimetry procedures. We report the risk of cancer other than

Y. Shimizu; W. J. Schull; H. Kato

1990-01-01

138

Age, growth and size interact with stress to determine life span and mortality  

PubMed Central

Individuals in a large experimental field population, of the short-lived perennial species Plantago lanceolata, were followed to determine the sources of variation that influence mortality and life span. The design included multiple age groups with initially similar genetic structure, which made it possible to separate age effects from period effects and to identify the genetic component to variation in life span. During a period of stress, individuals of all ages showed parallel increases in mortality but different cohorts experienced this period of high mortality at different ages. This then influenced the distribution of life spans across cohorts. Age and size-age interactions influenced mortality during the period of stress. Smaller individuals died but only if they were old. Additionally, growth and age interacted with stress such that older individuals had negative growth and high mortality whereas younger individuals had positive growth and relatively lower mortality during stress. The results of this study show that it is not simply the environment that can have a major impact on demography in natural populations, rather, age, size and growth can interact with the environment to influence mortality and life span when the environment is stressful.

Roach, Deborah Ann

2012-01-01

139

Age and Sex Differences in Strategies of Coping and Defense Across the Life Span  

Microsoft Academic Search

Age and sex differences in the use of coping and defense strategies were examined in a life-span sample of 381 individuals. Participants responded to 2 self-report measures assessing mechanisms of coping and defense and measures assessing their level of cognitive complexity. Older adults used a combination of coping and defense strategies indicative of greater impulse control and the tendency to

Manfred Diehl; Nathan Coyle; Gisela Labouvie-Vief

1996-01-01

140

A Life-Span Analysis of Rural Kansas Children's Mental and Social Development: First Year Report.  

ERIC Educational Resources Information Center

|This first year report of a life span analysis of rural Kansas children's mental and social development focuses on the children's cognitive development and the effect of family attitudes and child caring patterns on the children's development. The subjects, 62 rural children aged 3, 6, and 9 years, are to be interviewed annually. Initial analysis…

Poresky, Robert H.; And Others

141

Life span and biomass allocation of stunted black spruce clones in the subarctic environment  

Microsoft Academic Search

Summary 1 Slow growth, maintenance of a high leaf:wood ratio and adoption of a clonal growth habit, more than size per se, may increase the life span in trees species. The longevity of black spruce (Picea mariana (Mill.) BSP.) is increased from 200 to 300 years, when it grows as a clonal shrub. 2 We measured the surface area and

Marie-Josée Laberge; Serge Payette; Jean Bousquet

2000-01-01

142

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

ERIC Educational Resources Information Center

|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…

Dykas, Matthew J.; Cassidy, Jude

2011-01-01

143

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

144

Some Implications of Life Span Developmental Psychology for Adult Education and Learning  

Microsoft Academic Search

Many adult educators do not consider developmental psychology relevant to adult education because the bulk of developmental theory offers little for practical ap- plication. This paper describes a different perspective of adult psychology—life span developmental psychology—which holds great promise for educators in understanding better adult learning. We attempt to make explicit and to strengthen connections between developmental theory and adult

Thomas L. Pourchot; M. Cecil Smith

2004-01-01

145

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

PubMed Central

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.

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

146

COMPARISONS OF STRUCTURE AND LIFE SPAN IN ROOTS AND LEAVES AMONG TEMPERATE TREES  

Microsoft Academic Search

Global data sets provide strong evidence of convergence for leaf structure with leaf longevity such that species having thick leaves, low specific leaf area, low mass-based nitrogen concentrations, and low photosynthetic rates typically exhibit long leaf life span. Leaf longevity and corresponding leaf structure have also been widely linked to plant potential growth rate, plant competition, and nutrient cycling. We

Jennifer M. Withington; Peter B. Reich; Jacek Oleksyn; David M. Eissenstat

2006-01-01

147

Aging is associated with decreased maximal life span and accelerated senescence of bone marrow stromal cells  

Microsoft Academic Search

Age-related decrease in bone formation is well described. However, the cellular causes are not known. Thus, we have established cultures of bone marrow stromal cells (MSC) from young (aged 18–29 years, n = 6) and old (aged 68–81 years, n = 5) donors. MSC were serially passaged until reaching maximal life span. Cell growth, markers of cellular senescence, and osteogenic

Karin Stenderup; Jeannette Justesen; Christian Clausen; Moustapha Kassem

2003-01-01

148

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

ERIC Educational Resources Information Center

|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…

Kogan, Nathan; Tucker, Jennifer; Porter, Matthew

2011-01-01

149

Sleep-Disordered Breathing across the Life Span: Exploring a Human Disorder Using Animal Models  

Microsoft Academic Search

Sleep-disordered breathing (SDB) is a constellation of breathing disorders that occur during sleep. Obstructive sleep apnea (OSA), the most common form, is characterized by complete or partial airway obstruction, hypoventilation, and central apneas, all of which lead to recurrent episodes of hypoxia, hypercapnia, sleep fragmentation, and elevated sympathetic tone. OSA occurs throughout the life span and is associated with signifi

Estelle B. Gauda

2009-01-01

150

?1-Adrenergic receptor blockade extends the life span of Drosophila and long-lived mice.  

PubMed

Chronic treatment with ?-adrenergic receptor (?AR) agonists increases mortality and morbidity while ?AR antagonists (?-blockers) decrease all-cause mortality for those at risk of cardiac disease. Levels of sympathetic nervous system ?AR agonists and ?AR activity increase with age, and this increase may hasten the development of age-related mortality. Here, we show that ?-blockers extend the life span of healthy metazoans. The ?-blockers metoprolol and nebivolol, administered in food daily beginning at 12 months of age, significantly increase the mean and median life span of isocalorically fed, male C3B6F1 mice, by 10 and 6.4 %, respectively (P?life span, without affecting food intake or locomotion. Thus, ?AR antagonists are capable of directly extending the life span of two widely divergent metazoans, suggesting that these effects are phylogenetically highly conserved. Thus, long-term use of ?-blockers, which are generally well-tolerated, may enhance the longevity of healthy humans. PMID:23314750

Spindler, Stephen R; Mote, Patricia L; Li, Rui; Dhahbi, Joseph M; Yamakawa, Amy; Flegal, James M; Jeske, Daniel R; Li, Rui; Lublin, Alex L

2013-01-15

151

Extension of life span of Drosophila melanogaster by the inhibitors of tryptophan-kynurenine metabolism.  

PubMed

Upregulation of kynurenine (KYN) formation from tryptophan (TRY) was associated with aging in animal and human studies. TRY - KYN metabolism is affected by the activities of TRY 2,3-dioxygenase 2 (TDO) and ATP-binding cassette (ABC) transporter regulating TRY access to intracellular TDO. We studied the effects of TDO inhibitor, alpha-methyl tryptophan (aMT), and ABC transported inhibitor, 5-methyl tryptophan (5MT), on the life span of wild strain female Drosophila flies (Oregon-R). aMT and 5MT prolonged mean and maximum life span (by 27% and 43%, and 21% and 23%, resp.). The present results are the first observation of the extension of life span of Drosophila melanogaster by inhibitors of TRY - KYN metabolism, and in line with literature and previous studies on prolonged life span of TDO- and ABC-deficient female Drosophila mutants. Inhibition of TDO and ABC transporter activity might offer the new target for anti-aging and anti-AAMPD interventions. PMID:22041575

Oxenkrug, Gregory F; Navrotskaya, Valeria; Voroboyva, Lyudmila; Summergrad, Paul

2011-10-01

152

Life span and a new critical exponent for a degenerate parabolic equation  

Microsoft Academic Search

In this paper, we consider the positive solution of the Cauchy problem for the equationut=up?u+uq,p>1,q>1and give a secondary critical exponent of the behavior of initial value at infinity for the existence of global and nonglobal solutions of the Cauchy problem. Furthermore, the life span of solutions are also studied.

Yuhuan Li; Chunlai Mu

2004-01-01

153

Extension of life span of Drosophila melanogaster by the inhibitors of tryptophan-kynurenine metabolism  

PubMed Central

Upregulation of kynurenine (KYN) formation from tryptophan (TRY) was associated with aging in animal and human studies. TRY-KYN metabolism is affected by the activities of TRY 2,3-dioxygenase 2 (TDO) and AT P-binding cassette (ABC) transporter regulating TRY access to intracellular TDO. We studied the effects of TDO inhibitor, alpha-methyl tryptophan (aMT) and ABC transported inhibitor, 5-methyl tryptophan (5MT), on the life span of wild strain female Drosophila flies (Oregon-R). aMT and 5MT prolonged mean and maximum life span (by 27% and 43%, and 21% and 23%, resp.). The present results are the first observation of the extension of life span of Drosophila melanogaster by inhibitors of TRY-KYN metabolism, and in line with literature and previous studies on prolonged life span of TDO- and ABC-deficient female Drosophila mutants. Inhibition of TDO and ABC transporter activity might offer the new target for anti-aging interventions.

Navrotskaya, Valeriya; Vorobyova, Lyudmila; Summergrad, Paul

2011-01-01

154

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

PubMed Central

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.

K?l?cgun, Hasan; Goksen, Gulden

2012-01-01

155

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

ERIC Educational Resources Information Center

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…

Kogan, Nathan; Tucker, Jennifer; Porter, Matthew

2011-01-01

156

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

ERIC Educational Resources Information Center

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…

Dykas, Matthew J.; Cassidy, Jude

2011-01-01

157

Toward a Life Span Theory of Close Relationships: The Affective Relationships Model  

ERIC Educational Resources Information Center

|This article addresses how close relationships can be conceptualized so that they can be accurately understood over the life span. First, two typical clusters of theories of close relationships, the attachment theory and the social network theory, are compared and discussed with regard to their fundamental but controversial assumptions regarding…

Takahashi, Keiko

2005-01-01

158

Contributions of processing ability and knowledge to verbal memory tasks across the adult life-span  

Microsoft Academic Search

This study investigated the relationships of processing capacity and knowledge to memory measures that varied in retrieval difficulty and reliance on verbal knowledge in an adult life-span sample (N?=?341). It was hypothesized that processing ability (speed and working memory) would have the strongest relationship to tasks requiring active retrieval and that knowledge (vocabulary ability) would be related to verbal fluency

Trey Hedden; Gary Lautenschlager; Denise C. Park

2005-01-01

159

Control of the replicative life span of human fibroblasts by p16 and the polycomb protein Bmi1  

Microsoft Academic Search

senescence, but not quiescence, and extends replicative life span when overexpressed. Life span extension by Bmi-1 required the pRb, but not p53, tumor suppressor protein. Deletion analysis showed that the RING finger and helix-turn-helix domains of Bmi-1 were required for life span extension and suppression of p16. Further- more, a RING finger deletion mutant exhibited dominant negative activity, inducing p16

Koji Itahana; Ying Zou; Yoko Itahana; Jose-Luis Martinez; Christian Beausejour; Jacqueline J. L. Jacobs; Maarten van Lohuizen; Vimla Band; Judith Campisi; Goberdhan P. Dimri

2003-01-01

160

Requirement of NAD and SIR2 for Life-Span Extension by Calorie Restriction in Saccharomyces cerevisiae  

Microsoft Academic Search

Calorie restriction extends life-span in a wide variety of organisms. Although it has been suggested that calorie restriction may work by reducing the levels of reactive oxygen species produced during respiration, the mechanism by which this regimen slows aging is uncertain. Here, we mimicked calorie restriction in yeast by physiological or genetic means and showed a substantial extension in life-span.

Su-Ju Lin; Pierre-Antoine Defossez; Leonard Guarente

2000-01-01

161

Rapamycin, but not resveratrol or simvastatin, extends life span of genetically heterogeneous mice.  

PubMed

Rapamycin was administered in food to genetically heterogeneous mice from the age of 9 months and produced significant increases in life span, including maximum life span, at each of three test sites. Median survival was extended by an average of 10% in males and 18% in females. Rapamycin attenuated age-associated decline in spontaneous activity in males but not in females. Causes of death were similar in control and rapamycin-treated mice. Resveratrol (at 300 and 1200 ppm food) and simvastatin (12 and 120 ppm) did not have significant effects on survival in male or female mice. Further evaluation of rapamycin's effects on mice is likely to help delineate the role of the mammalian target of rapamycin complexes in the regulation of aging rate and age-dependent diseases and may help to guide a search for drugs that retard some or all of the diseases of aging. PMID:20974732

Miller, Richard A; Harrison, David E; Astle, C M; Baur, Joseph A; Boyd, Angela Rodriguez; de Cabo, Rafael; Fernandez, Elizabeth; Flurkey, Kevin; Javors, Martin A; Nelson, James F; Orihuela, Carlos J; Pletcher, Scott; Sharp, Zelton Dave; Sinclair, David; Starnes, Joseph W; Wilkinson, J Erby; Nadon, Nancy L; Strong, Randy

2010-10-25

162

Statistical analysis regarding the effects of height and weight on life span of the domestic dog.  

PubMed

This study was undertaken to determine the association between life spans and breed size in the dog, based upon data derived from the pet population. Seventy-seven American Kennel Club breeds were analyzed with data collected for more than 700 dogs. Multiple linear regression analysis was carried out with longevity as the dependent variable and height or weight as the independent variable. A negative correlation was observed between height and longevity (r=-0.603, p<0.05), and between weight and longevity (r=-0.679, p<0.05). Weight was the significant predictor of life span (p<0.001), revealing that breeds smaller by weight generally live longer than heavier breeds. These data form the ground work for investigations of aging utilizing the dog as a model and provide owners with a quantitative method for predicting lifespan of dog breeds, thereby aiding in pet selection. PMID:16919689

Greer, Kimberly A; Canterberry, Sarah C; Murphy, Keith E

2006-08-21

163

Toward an Integrative Science of Life-Span Development and Aging  

PubMed Central

The study of aging demands an integrative life-span developmental framework, involving interdisciplinary collaborations and multiple methodological approaches for understanding how and why individuals change, in both normative and idiosyncratic ways. We highlight and summarize some of the issues encountered when conducting integrative research for understanding aging-related change, including, the integration of results across different levels of analysis; the integration of theory, design, and analysis; and the synthesis of results across studies of aging. We emphasize the necessity of longitudinal designs for understanding development and aging and discuss methodological issues that should be considered for achieving reproducible research on within-person processes. It will be important that current and future studies permit opportunities for quantitative comparison across populations given the extent to which historical shifts and cultural differences influence life-span processes and aging-related outcomes.

Piccinin, Andrea M.

2010-01-01

164

Synthesis of nursing care across the life span using laboratory simulation: a senior-level course.  

PubMed

The use of simulation activities in nursing education helps students develop critical thinking skills and also enhances student learning and confidence in the practicum setting. As students complete their education, they need to integrate all they have learned to design care for patients across the life span. This article describes a senior-level skills laboratory simulation course in a baccalaureate nursing program designed to foster the shift toward independent critical thinking. The primary goal of the course was synthesis and application of students' cumulative knowledge through teamwork, assessing, critical thinking, prioritizing, and decision making in care for diverse patients across the life span. Specifics of course development and design are included along with student responses and lessons learned. PMID:21053854

Slager, Dianne; Feenstra, Cheryl; Ayoola, Adejoke; Flikkema, Mary; Bartels, Shelly

2010-10-29

165

Rapamycin, But Not Resveratrol or Simvastatin, Extends Life Span of Genetically Heterogeneous Mice  

PubMed Central

Rapamycin was administered in food to genetically heterogeneous mice from the age of 9 months and produced significant increases in life span, including maximum life span, at each of three test sites. Median survival was extended by an average of 10% in males and 18% in females. Rapamycin attenuated age-associated decline in spontaneous activity in males but not in females. Causes of death were similar in control and rapamycin-treated mice. Resveratrol (at 300 and 1200 ppm food) and simvastatin (12 and 120 ppm) did not have significant effects on survival in male or female mice. Further evaluation of rapamycin’s effects on mice is likely to help delineate the role of the mammalian target of rapamycin complexes in the regulation of aging rate and age-dependent diseases and may help to guide a search for drugs that retard some or all of the diseases of aging.

Harrison, David E.; Astle, C. M.; Baur, Joseph A.; Boyd, Angela Rodriguez; de Cabo, Rafael; Fernandez, Elizabeth; Flurkey, Kevin; Javors, Martin A.; Nelson, James F.; Orihuela, Carlos J.; Pletcher, Scott; Sharp, Zelton Dave; Sinclair, David; Starnes, Joseph W.; Wilkinson, J. Erby; Nadon, Nancy L.; Strong, Randy

2011-01-01

166

Mitochondria-mediated hormetic response in life span extension of calorie-restricted Saccharomyces cerevisiae.  

PubMed

Calorie restriction (CR) is the only proven regimen, which confers lifespan extension benefits across the various phyla right from unicellular organisms like yeast to primates. In a bid to elucidate the mechanism of calorie-restriction-mediated life span extension, the role of mitochondria in the process was investigated. In this study, we found that the mitochondrial content in CR cells remains unaltered as compared to cells grown on nonrestricted media. However, mitochondria isolated from CR cells showed increased respiration and elevated reactive oxygen species levels without augmenting adenosine triphosphate (ATP) generation. The antioxidant defense system was amplified in CR mitochondria, and in CR cells a cross protection to hydrogen-peroxide-induced stress was also observed. Moreover, we also documented that a functional electron transport chain was vital for the life span extension benefits of calorie restriction. Altogether, our results indicate that calorie restriction elicits mitohormetic effect, which ultimately leads to longevity benefit. PMID:20640543

Sharma, Praveen Kumar; Agrawal, Vineet; Roy, Nilanjan

2010-07-17

167

Yeast HAT1 and HAT2 deletions have different life-span and transcriptome phenotypes  

Microsoft Academic Search

HAT-B is a yeast histone acetyltransferase composed of Hat1, Hat2 and Hif1 proteins. We demonstrate that a hat2 mutant or a hat1hat2 double mutant, but not a hat1 mutant, have an extended life-span. Transcriptome analysis shows that the single hat mutants are not very different from wild type. However, the comparison of the hat1 and hat2 transcriptomes shows that they

Lorena E. Rosaleny; Oreto Antúnez; Ana B. Ruiz-García; José E. Pérez-Ortín; Vicente Tordera

2005-01-01

168

Dependence of the life span of the honeybee ( Apis mellifica ) upon flight performance and energy consumption  

Microsoft Academic Search

The life span of worker-honeybees is determined by the duration of the hive-period and of the foraging period (Figs. 1,2). The duration of the forgaing period is regulated in the following way: Total flight performance of the individual bee seems to be fixed. Daily flight performance strongly affects total flight duration. High daily flight performance decreases maximal flight duration and

Angelika Neukirch

1982-01-01

169

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

Microsoft Academic Search

This study aimed to investigate women's body image across the entire life span from within the theoretical perspective provided by objectification theory (B. L. Fredrickson & T.-A. Roberts, 1997). In a cross-sectional study, a sample of 322 women ranging in age from 20 to 84 years completed a questionnaire measuring body dissatisfaction, self-objectification, and its proposed consequences. Although body dissatisfaction

Marika Tiggemann; Jessica E. Lynch

2001-01-01

170

Independence of Age-Related Influences on Cognitive Abilities Across the Life Span  

Microsoft Academic Search

Age-related increases in childhood and age-related decreases in adulthood have been reported for a wide variety of cognitive variables, but relatively little research has addressed the question of the independence of these influences. In this project, cross-sectional life span data (age 5 to 94 years) from the nationally representative sample used to establish the norms for the Woodcock–Johnson Psycho-Educational Battery

Timothy A. Salthouse

1998-01-01

171

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

Microsoft Academic Search

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 patterns of results that have emerged from these studies. The central proposition is that individuals

Matthew J. Dykas; Jude Cassidy

2011-01-01

172

Elimination of Replication Block Protein Fob1 Extends the Life Span of Yeast Mother Cells  

Microsoft Academic Search

A cause of aging in yeast is the accumulation of circular species of ribosomal DNA (rDNA) arising from the 100–200 tandemly repeated copies in the genome. We show here that mutation of the FOB1 gene slows the generation of these circles and thus extends life span. Fob1p is known to create a unidirectional block to replication forks in the rDNA.

Pierre-Antoine Defossez; Reeta Prusty; Matt Kaeberlein; Su-Ju Lin; Paul Ferrigno; Pamela A. Silver; Ralph L. Keil; Leonard Guarente

1999-01-01

173

Increased aerobic metabolism is essential for the beneficial effects of caloric restriction on yeast life span  

Microsoft Academic Search

Calorie restriction is a dietary regimen capable of extending life span in a variety of multicellular organisms. A yeast model\\u000a of calorie restriction has been developed in which limiting the concentration of glucose in the growth media of Saccharomyces cerevisiae leads to enhanced replicative and chronological longevity. Since S. cerevisiae are Crabtree-positive cells that present repression of aerobic catabolism when

Graciele A. Oliveira; Erich B. Tahara; Andreas K. Gombert; Mario H. Barros; Alicia J. Kowaltowski

2008-01-01

174

Transient Expression of Human Telomerase Extends the Life Span of Normal Human Fibroblasts  

Microsoft Academic Search

We utilized the Cre\\/lox recombination system to transiently express the catalytic subunit of telomerase (hTERT) in normal diploid foreskin fibroblasts (BJ cells). A retroviral construct containing an hTERT cDNA, flanked by loxP-sites was introduced into near senescent BJ cells (population doubling 85). At population doubling (PD) 92, which exceeds the typical life span of these cells, we excised the gene

Susanne Steinert; Jerry W. Shay; Woodring E. Wright

2000-01-01

175

An empirical analysis of software life spans to determine the planning horizon for new software  

Microsoft Academic Search

This paper presents an empirical analysis of the life span of over 180 systems aimed at developing a model for determining\\u000a the planning horizon for new software at the business case stage of software acquisition. At this early stage, the firm has\\u000a limited knowledge about the project, but must make crucial decisions, such as scope (breadth of requirements), approach (both

William Richmond; Paul Nelson; Sanjog Misra

2006-01-01

176

Mitochondria-mediated hormetic response in life span extension of calorie-restricted Saccharomyces cerevisiae  

Microsoft Academic Search

Calorie restriction (CR) is the only proven regimen, which confers lifespan extension benefits across the various phyla right\\u000a from unicellular organisms like yeast to primates. In a bid to elucidate the mechanism of calorie-restriction-mediated life\\u000a span extension, the role of mitochondria in the process was investigated. In this study, we found that the mitochondrial content\\u000a in CR cells remains unaltered

Praveen Kumar Sharma; Vineet Agrawal; Nilanjan Roy

2011-01-01

177

Examining the Relationship between Life Expectancy, Reproduction, and Educational Attainment  

Microsoft Academic Search

Life history theory aims to explain the relationship between life events, recognizing that the fertility and growth schedules\\u000a of organisms are dependent on environmental conditions and an organism’s ability to extract resources from its environment.\\u000a Using models from life history theory, we predict life expectancy to be positively correlated with educational investments\\u000a and negatively correlated with adolescent reproduction and total

Nicola L. Bulled; Richard Sosis

2010-01-01

178

Extension of chronological life span in yeast by decreased TOR pathway signaling  

PubMed Central

Chronological life span (CLS) in Saccharomyces cerevisiae, defined as the time cells in a stationary phase culture remain viable, has been proposed as a model for the aging of post-mitotic tissues in mammals. We developed a high-throughput assay to determine CLS for ?4800 single-gene deletion strains of yeast, and identified long-lived strains carrying mutations in the conserved TOR pathway. TOR signaling regulates multiple cellular processes in response to nutrients, especially amino acids, raising the possibility that decreased TOR signaling mediates life span extension by calorie restriction. In support of this possibility, removal of either asparagine or glutamate from the media significantly increased stationary phase survival. Pharmacological inhibition of TOR signaling by methionine sulfoximine or rapamycin also increased CLS. Decreased TOR activity also promoted increased accumulation of storage carbohydrates and enhanced stress resistance and nuclear relocalization of the stress-related transcription factor Msn2. We propose that up-regulation of a highly conserved response to starvation-induced stress is important for life span extension by decreased TOR signaling in yeast and higher eukaryotes.

Powers, R. Wilson; Kaeberlein, Matt; Caldwell, Seth D.; Kennedy, Brian K.; Fields, Stanley

2006-01-01

179

Identification of respiratory chain gene mutations that shorten replicative life span in yeast.  

PubMed

Aging is the progressive accumulation of alterations in cells that elevates the risk of death. The mitochondrial theory of aging postulates that free radicals produced by the mitochondrial respiratory system contribute to the aging process. However, the roles of individual electron transfer chain (ETC) components in cellular aging have not been elucidated. In this study, we analyzed the replicative life span of 73 yeast deletion mutants lacking the genes of the mitochondrial electron transfer chain system, and found that nine of these mutants (?nde1, ?tcm62, ?rip1, ?cyt1, ?qrc8, ?pet117, ?cox11, ?atp11, ?fmc1) had significantly shorter life spans. These mutants had lower rates of respiration and were slightly sensitive to exogenous administration of hydrogen peroxide. However, only two of them, ?nde1 and ?fmc1, produced higher amounts of intrinsic superoxide radicals in the presence of glucose compared to that of wild type cells. Interestingly, there were no significant alterations in the mitochondrial membrane potentials of these mutants. We speculate that the shorter life spans of ETC mutants result from multiple mechanisms including the low respiration rate and low energy production rather than just a ROS-dependent path. PMID:22137892

Hacioglu, Elise; Demir, Ayse Banu; Koc, Ahmet

2011-11-25

180

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions  

PubMed Central

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.

2012-01-01

181

Life span of C57 mice as influenced by radiation dose, dose rate, and age at exposure  

SciTech Connect

This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from /sup 60/Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates ranging from 0.7 to 36,000 R/day. The ages of the mice at exposure were newborn, 2, 6, or 15 months. Two replications were completed. Although death was the primary endpoint, we did perform gross necropsies. The life span findings are variable, but we found no consistent shortening compared to control life spans. Therefore, we cannot logically extrapolate life shortening to lower doses, from the data we have obtained. In general, the younger the animals were at the beginning of exposure, the longer their life spans were compared to those of controls. This relationship weakened at the higher doses and dose rates, as mice in these categories tended not to have significantly different life spans from controls. Using life span as a criterion, we find this study suggests that some threshold dosage may exist beyond which effects of external irradiation may be manifested. Up to this threshold, there is no shortening effect on life span compared to that of control mice. Our results are in general agreement with the results of other researchers investigating human and other animal life span effects on irradiation.

Spalding, J.F.; Thomas, R.G.; Tietjen, G.L.

1982-10-01

182

Submandibular salivary glands: influence on growth rate and life span in mice  

Microsoft Academic Search

Submandibular glands accumulate a variety of growth factors, especially in male mice. Surgical excision of these glands (sialoadenectomy)\\u000a results in alterations in several organs and systems including the liver, skin and reproductive system. We studied the life-long\\u000a consequences of sialoadenectomy in male mice. Animals were operated at the age of 10 weeks. Thereafter, body weight and food\\u000a and water intake were

Ignasi Ramírez; Maria Soley

2011-01-01

183

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

NASA Astrophysics Data System (ADS)

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.

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

184

Life Satisfaction, Self-Esteem, and Subjective Age in Women across the Life Span  

ERIC Educational Resources Information Center

|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…

Borzumato-Gainey, Christine; Kennedy, Alison; McCabe, Beth; Degges-White, Suzanne

2009-01-01

185

The life span of Drosophila melanogaster is affected by melatonin and thioctic acid.  

PubMed

Aging and reduced longevity are due in part to the action of free radicals (FR). Melatonin (Mel) and thioctic acid (TA) are effective in protecting against the damage caused by FR. In this study, the effect of Mel and TA on the life cycle of Drosophila melanogaster was determined. We used a control group of flies, another group that was provided with Mel (0.43 mM) throughout their life cycle (Mel-c), a third group received Mel upon reaching adulthood (Mel-a) and two groups were fed with TA (2.15 mM) in the same manner (TA-c and TA-a). The number of eclosed, survival, phenotype changes, motor activity and the content of malondialdehyde (MDA) was evaluated in each group. Mel-c increased the eclosion rate and the motor activity of the flies. Mel-c and Mel-a increased the life span and decreased the concentrations of MDA. By contrast, TA-c diminished the eclosion rate, produced phenotypic changes and increased MDA levels and motor activity of the flies. TA-a extended the life span of flies, and did not alter MDA levels and motor activity when compared with the control group. In conclusion, Mel mitigated the effects caused by FR generated during aging, while TA-c increased lipid peroxidation and altered the phenotype of flies. PMID:23248969

Terán, Raikelin; Bonilla, Ernesto; Medina-Leendertz, Shirley; Mora, Marylú; Villalobos, Virginia; Paz, Milagros; Arcaya, José L

2012-09-01

186

Dead or Alive: Deformed Wing Virus and Varroa destructor Reduce the Life Span of Winter Honeybees  

PubMed Central

Elevated winter losses of managed honeybee colonies are a major concern, but the underlying mechanisms remain controversial. Among the suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae, and associated viruses. Here we hypothesize that pathogens reduce the life expectancy of winter bees, thereby constituting a proximate mechanism for colony losses. A monitoring of colonies was performed over 6 months in Switzerland from summer 2007 to winter 2007/2008. Individual dead workers were collected daily and quantitatively analyzed for deformed wing virus (DWV), acute bee paralysis virus (ABPV), N. ceranae, and expression levels of the vitellogenin gene as a biomarker for honeybee longevity. Workers from colonies that failed to survive winter had a reduced life span beginning in late fall, were more likely to be infected with DWV, and had higher DWV loads. Colony levels of infection with the parasitic mite Varroa destructor and individual infections with DWV were also associated with reduced honeybee life expectancy. In sharp contrast, the level of N. ceranae infection was not correlated with longevity. In addition, vitellogenin gene expression was significantly positively correlated with ABPV and N. ceranae loads. The findings strongly suggest that V. destructor and DWV (but neither N. ceranae nor ABPV) reduce the life span of winter bees, thereby constituting a parsimonious possible mechanism for honeybee colony losses.

Evans, Jay D.; Chen, Yan Ping; Gauthier, Laurent; Neumann, Peter

2012-01-01

187

Comparative transcriptional pathway bioinformatic analysis of dietary restriction, Sir2, p53 and resveratrol life span extension in Drosophila  

PubMed Central

A multiple comparison approach using whole genome transcriptional arrays was used to identify genes and pathways involved in calorie restriction/dietary restriction (DR) life span extension in Drosophila. Starting with a gene centric analysis comparing the changes in common between DR and two DR related molecular genetic life span extending manipulations, Sir2 and p53, lead to a molecular confirmation of Sir2 and p53's similarity with DR and the identification of a small set of commonly regulated genes. One of the identified upregulated genes, takeout, known to be involved in feeding and starvation behavior, and to have sequence homology with Juvenile Hormone (JH) binding protein, was shown to directly extend life span when specifically overexpressed. Here we show that a pathway centric approach can be used to identify shared physiological pathways between DR and Sir2, p53 and resveratrol life span extending interventions. The set of physiological pathways in common among these life span extending interventions provides an initial step toward defining molecular genetic and physiological changes important in life span extension. The large overlap in shared pathways between DR, Sir2, p53 and resveratrol provide strong molecular evidence supporting the genetic studies linking these specific life span extending interventions.

Antosh, Michael; Whitaker, Rachel; Kroll, Adam; Hosier, Suzanne; Chang, Chengyi; Bauer, Johannes; Cooper, Leon

2011-01-01

188

Drosophila foxo acts in males to cause sexual-dimorphism in tissue-specific p53 life span effects  

PubMed Central

Sex-specific selective pressures are hypothesized to lead to sexually antagonistic gene functions that contribute to phenotypes such as aging and cancer. However, relatively little is known about the identity of such genes and possible mechanisms. Here we report that nervous system-specific over-expression of wild-type p53 in Drosophila caused decreased life span in males and increased life span in females. In contrast, tissue-general over-expression produced the opposite pattern: increased life span in males and decreased life span in females. In a foxo null background, p53 life span effects in males were reversed, becoming similar to the effects in females. In contrast, a Sir2 null background tended to reduce the magnitude of p53 effects. The data demonstrate that wild-type p53 over-expression can regulate life span independent of foxo, and suggest that foxo acts in males to produce sexually antagonistic life span effects of p53.

Shen, Jie; Tower, John

2009-01-01

189

From children to adults: motor performance across the life-span.  

PubMed

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

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

2012-06-18

190

Photosynthetic thermotolerance of woody savanna species in China is correlated with leaf life span  

PubMed Central

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.

Zhang, Jiao-Lin; Poorter, L.; Hao, Guang-You; Cao, Kun-Fang

2012-01-01

191

Mutants in the Saccharomyces cerevisiae RAS2 gene influence life span, cytoskeleton, and regulation of mitosis.  

PubMed

We investigated the phenotypic consequences in Saccharomyces cerevisiae of a disruption allele (ras2::LEU2) and of a dominant mutant form (RAS2ala18,val19) of RAS2. In addition to the phenotypes described earlier for these mutants, we observed a small increase in the life span for the disruption allele and a drastic decrease of life span for the dominant mutant form, as compared with the isogenic wild type. This was found by analyzing these alleles in two different genetic backgrounds with nearly the same results. Life spans were determined by micromanipulating mother cells and counting generations until no further cell division occurred. A morphological analysis of the terminal phenotypes of very old mother cells was performed showing enlarged or rounded cells and in some cases elongated buds, some of which were difficult to separate from the mother cell. This was observed in wild-type cells, as well as mutant cells. However, the dominant RAS2 mutant (but not the wild-type or ras2::LEU2 mutant cells) after 2 days on complex media displayed phenotypes similar to the terminal phenotype of old mothers. A substantial fraction of the cells were enlarged and generated elongated buds, they lost Calcofluor staining of the bud scars, the cell surface appeared folded, the actin cytoskeleton was aberrant, and the mitotic spindle and the cytoplasmic microtubles were defective in their proper orientation, resulting in aberrant mitoses and empty buds. These phenotypic characteristics of the RAS2ala18,val19 mutation could be causative for the previously observed rapid loss of viability of these cells in stationary phase. PMID:9304788

Pichová, A; Vondráková, D; Breitenbach, M

1997-08-01

192

Health span extension by later-life caloric or dietary restriction: a view based on rodent studies  

Microsoft Academic Search

In spite of the potential benefit of lifelong food restriction to retard aging and extend life span, it is unrealistic in human. The restriction late in life may be more practical. There are, however, only limited studies on the effect of late onset caloric or dietary restriction. We and other investigators have shown that the late life restriction rejuvenates some

Sataro Goto

2006-01-01

193

Lifetime Reproductive Performance of Goats as a Function of Growth Traits and Reproductive Performance Early in Life  

Microsoft Academic Search

Mellado, M., Mellado, J., García, J.E. and López, R. 2005. Lifetime reproductive performance of goats as a function of growth traits and reproductive performance early in life. J. Appl. Anim. Res., 27: 113–116.The primary aim of this study was to evaluate the association between reproductive performance of 476 dairy goats in their first reproductive cycle with reproductive efficiency late in

M. Mellado; J. Mellado; J. E. García; R. López

2005-01-01

194

Redistribution of Silencing Proteins from Telomeres to the Nucleolus Is Associated with Extension of Life Span in S. cerevisiae  

Microsoft Academic Search

A prior genetic study indicated that activity of Sir silencing proteins at a hypothetical AGE locus is essential for long life span. In this model, the SIR4-42 mutation would direct the Sir protein complex to the AGE locus, giving rise to a long life span. We show by indirect immunofluorescence that Sir3p and Sir4p are redirected to the nucleolus in

Brian K Kennedy; Monica Gotta; David A Sinclair; Kevin Mills; David S McNabb; Mala Murthy; Sally M Pak; Thierry Laroche; Susan M Gasser; Leonard Guarente

1997-01-01

195

Dominant-negative Dmp53 extends life span through the dTOR pathway in D. melanogaster  

PubMed Central

Expression of dominant-negative (DN) versions of the Drosophila ortholog of the tumor suppressor p53 extends fly life span in a Calorie Restriction (CR) dependent manner. DN-Dmp53 expression furthermore leads to reduction of Drosophila insulin-like peptide (dILP) 2 mRNA levels and a decrease in insulin/insulin-like growth factor-signaling activity (IIS) in the fly fat body. It is unclear by which mechanisms DN-Dmp53 extends longevity, and whether modulation of insulin-signaling activity plays a pivotal role in life span regulation by Dmp53. Here we show that life span extension due to DN-Dmp53 expression is likely due to reduction of Dmp53 activity and that decreased Dmp53 activity does not extend life span when dILP2 is concomitantly over expressed. Furthermore, extended longevity due to DN-Dmp53 expression does not further extend the life span of flies over expressing the IIS associated transcription factor dFoxO, indicating that DN-Dmp53-dependent life span extension may be related to IIS. However, reduction of dFoxO levels does not decrease DN-Dmp53-dependent longevity extension. Interestingly, when DN-Dmp53 is expressed in flies lacking the translation initiation controlling factor Thor/4E-BP, the downstream target of dTOR signaling, no increase in life span is observed. Taken together, these data suggest that Dmp53 may affect life span by differentially engaging the IIS and dTor pathways.

Bauer, Johannes H.; Chang, Chengyi; Bae, Gina; Morris, Siti Nur Sarah; Helfand, Stephen L.

2010-01-01

196

Endogenous sink-source interactions and soil nitrogen regulate leaf life-span in an evergreen shrub.  

PubMed

How the balance between exogenous and endogenous nitrogen for shoot growth varies with soil nitrogen availability, and its consequences on leaf life-span, have rarely been studied within a single species in the field. In this study, we investigated two Rhododendron ferrugineum populations with contrasting leaf life-span. Soil nitrogen availability and nitrogen resorption of different leaf age classes were assessed, as were the interactions between plant compartments, using (15)N labelling and sink organ suppression. The population growing on poorer soil had a shorter leaf life-span (17.9 vs 21.5 months) and a higher net contribution of leaf reserves to shoot growth (32% vs 15%), achieved by faster nitrogen resorption and greater shedding of young nitrogen-rich leaves. For both populations, wood contributed to over 40% of shoot nitrogen demand. Both the negative relationship between current-year shoot mass and the percentage of 1-yr-old attached leaves and the delay of leaf shedding after bud removal suggest that shoot development has a strong effect on leaf life-span. Our results suggest that, contrary to the evolutionary response, plastic response to low soil nitrogen could reduce leaf life-span in evergreen plants. In addition, leaf life-span seems to be strongly influenced by the discrepancy between shoot nitrogen demand and soil nitrogen uptake rather than nitrogen demand alone. PMID:19500264

Marty, C; Lamaze, T; Pornon, A

2009-06-04

197

Regulation of Yeast Chronological Life Span by TORC1 via Adaptive Mitochondrial ROS Signaling  

PubMed Central

Summary Here we show that yeast strains with reduced target of rapamycin (TOR) signaling have greater overall mitochondrial electron transport chain activity during growth that is efficiently coupled to ATP production. This metabolic alteration increases mitochondrial membrane potential and superoxide production that we propose supplies an adaptive signal during growth that extends chronological life span (CLS). In strong support of this concept, uncoupling respiration during growth or over-expressing mitochondrial manganese superoxide dismutase significantly curtails CLS extension in tor1? strains, and treatment of wild-type strains with either rapamycin (to inhibit TORC1) or menadione (to generate mitochondrial ROS) during growth is sufficient to extend CLS. Finally, extension of CLS by reduced TORC1/Sch9p-mitochondrial signaling occurs independently of Rim15p and is not a function of changes in media acidification/composition. Considering the conservation of TOR-pathway effects on life span, mitochondrial ROS signaling may be an important mechanism of longevity regulation in higher organisms.

Pan, Yong; Schroeder, Elizabeth A.; Ocampo, Alejandro; Barrientos, Antoni; Shadel, Gerald S.

2011-01-01

198

Minocycline, but not ascorbic acid, increases motor activity and extends the life span of Drosophila melanogaster.  

PubMed

In the present study we compared the effects of minocycline and ascorbic acid in the life span, motor activity and lipid peroxidation of Drosophila melanogaster, in an effort to find a substance capable of providing protection against oxidative stress in aging. In the flies treated with minocycline a very significant increase in the life span (101 +/- 1.33 days) was observed when compared to those treated with ascorbic acid and controls (42.3% and 38.4%, respectively). The motor activity of minocycline treated flies also increased significantly with respect to control and ascorbic acid fed flies, from the 3rd to the 9th week of treatment. With regard to lipid peroxidation, it was found that the levels of malondialdehyde (MDA) in flies treated with minocycline showed no statistical differences to the control on the first day of treatment, but a significantly lower content on the day of 50% survival. In contrast, in flies treated with ascorbic acid significantly elevated levels of MDA compared to control and minocycline treated flies were detected throughout. These results suggest a protective effect of minocycline against oxidative stress and aging in D. melanogaster. An inhibitory effect on reactive oxygen species production may be an important contributing factor. PMID:23947005

Mora, Marylhi; Medina-Leendertz, Shirley J; Bonilla, Ernesto; Terán, Raikelin E; Paz, Milagros C; Arcaya, José Luis

2013-06-01

199

HuR maintains a replicative life span by repressing the ARF tumor suppressor.  

PubMed

p19(ARF) plays an essential role in the senescence of mouse cells, and its expression is lost by methylation or deletion of the ARF locus; otherwise, p53 is inactivated to bypass senescence. ARF expression is tightly regulated, but little is known about its posttranscriptional regulation. Here, we show that an RNA-binding protein, HuR (human antigen R), represses ARF mRNA translation, thereby maintaining the replicative life span of mouse embryonic fibroblasts (MEFs). Loss of HuR results in premature senescence, with concomitant increases in p19(ARF) but not p16(Ink4a) levels, and this senescence is not observed in ARF-null MEFs that retain an intact Ink4a locus. HuR depletion does not alter ARF transcription or stability but enhances ribosome association with ARF mRNA. Under these conditions, ARF mRNA accumulates in nucleoli, where it associates with nucleolin. Furthermore, adipose-specific deletion of the HuR gene results in increased p19(ARF) expression in aged animals, which is accompanied by decreased insulin sensitivity. Together, our findings demonstrate that p19(ARF) is also regulated at the translational level, and this translational regulation restrains the cellular life span and tissue functions in vivo. PMID:23508105

Kawagishi, Hiroyuki; Hashimoto, Michihiro; Nakamura, Hideaki; Tsugawa, Takayuki; Watanabe, Atsushi; Kontoyiannis, Dimitris L; Sugimoto, Masataka

2013-03-18

200

Rapamycin extends life span of Rb1+/- mice by inhibiting neuroendocrine tumors.  

PubMed

Chronic treatment of mice with an enterically released formulation of rapamycin (eRapa) extends median and maximum life span, partly by attenuating cancer. The mechanistic basis of this response is not known. To gain a better understanding of thesein vivo effects, we used a defined preclinical model of neuroendocrine cancer, Rb1+/- mice. Previous results showed that diet restriction (DR) had minimal or no effect on the lifespan of Rb1+/- mice, suggesting that the beneficial response to DR is dependent on pRb1. Since long-term eRapa treatment may at least partially mimic chronic DR in lifespan extension, we predicted that it would have a minimal effect in Rb1+/- mice. Beginning at 9 weeks of age until death, we fed Rb1+/- mice a diet without or with eRapa at 14 mg/kg food, which results in an approximate dose of 2.24 mg/kg body weight per day, and yielded rapamycin blood levels of about 4 ng/ml. Surprisingly, we found that eRapa dramatically extended life span of both female and male Rb1+/- mice, and slowed the appearance and growth of pituitary and decreased the incidence of thyroid tumors commonly observed in these mice. In this model, eRapa appears to act differently than DR, suggesting diverse mechanisms of action on survival and anti-tumor effects. In particular the beneficial effects of rapamycin did not depend on the dose of Rb1. PMID:23454836

Livi, Carolina B; Hardman, Rulon L; Christy, Barbara A; Dodds, Sherry G; Jones, Diane; Williams, Charnae; Strong, Randy; Bokov, Alex; Javors, Martin A; Ikeno, Yuji; Hubbard, Gene; Hasty, Paul; Sharp, Zelton Dave

2013-02-01

201

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

PubMed Central

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.

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

2006-01-01

202

Regulation of yeast chronological life span by TORC1 via adaptive mitochondrial ROS signaling.  

PubMed

Here we show that yeast strains with reduced target of rapamycin (TOR) signaling have greater overall mitochondrial electron transport chain activity during growth that is efficiently coupled to ATP production. This metabolic alteration increases mitochondrial membrane potential and reactive oxygen species (ROS) production, which we propose supplies an adaptive signal during growth that extends chronological life span (CLS). In strong support of this concept, uncoupling respiration during growth or increasing expression of mitochondrial manganese superoxide dismutase significantly curtails CLS extension in tor1? strains, and treatment of wild-type strains with either rapamycin (to inhibit TORC1) or menadione (to generate mitochondrial ROS) during growth is sufficient to extend CLS. Finally, extension of CLS by reduced TORC1/Sch9p-mitochondrial signaling occurs independently of Rim15p and is not a function of changes in media acidification/composition. Considering the conservation of TOR-pathway effects on life span, mitochondrial ROS signaling may be an important mechanism of longevity regulation in higher organisms. PMID:21641548

Pan, Yong; Schroeder, Elizabeth A; Ocampo, Alejandro; Barrientos, Antoni; Shadel, Gerald S

2011-06-01

203

Reproductive and Life History Parameters of Wild Female Macaca assamensis  

PubMed Central

Information on basic reproductive parameters and life-history traits is crucial for the understanding of primate evolution, ecology, social behavior, and reproductive strategies. Here, we report 4 yr of data on reproductive and life-history traits for wild female Assamese macaques (Macaca assamensis) at Phu Khieo Wildlife Sanctuary, northeastern Thailand. During 2 consecutive reproductive seasons, we investigated reproductive behavior and sexual swelling size in 16 females and collected 1832 fecal samples. Using enzyme immunoassays, we measured fecal estrogen and progesterone metabolites to assess ovarian activity and timing of ovulation and to ascertain conceptions and pregnancies. Timing of reproduction was strictly seasonal (births: April–July, 86% in April–June, 4 yr, n?=?29; conceptions: October–February, 65% in December–January, 2 yr, n?=?17). Females showed no cyclic ovarian activity outside the mating season and conceived in their first or second cycle (mean: 1.2 cycles to conception, n?=?13). Gestation length was on average 164.2 d (range: 158–170, n?=?10), and females had their first infant at an age of 5 yr (n?=?4). Interbirth intervals were bimodally distributed, with females giving birth on average every 13.9 or 23.2 mo. Shorter interbirth intervals were linked to early parturition within the birth season. Most females displayed subcaudal sexual swellings which, however, did not reliably indicate female reproductive status or fertility. Overall, our results fall within the range of findings reported for other macaque species. These results thus add to the growing body of information available for wild macaques, facilitating comparative studies for a better understanding of interspecific differences in social and reproductive patterns.

Schulke, Oliver; Heistermann, Michael; Ostner, Julia

2010-01-01

204

Spermatozoid life-span of two brown seaweeds, Saccharina japonica and Undaria pinnatifida, as measured by fertilization efficiency  

NASA Astrophysics Data System (ADS)

During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60-120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S. japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia.

Li, Jing; Pang, Shaojun; Liu, Feng; Shan, Tifeng; Gao, Suqin

2013-07-01

205

Yeast HAT1 and HAT2 deletions have different life-span and transcriptome phenotypes.  

PubMed

HAT-B is a yeast histone acetyltransferase composed of Hat1, Hat2 and Hif1 proteins. We demonstrate that a hat2 mutant or a hat1hat2 double mutant, but not a hat1 mutant, have an extended life-span. Transcriptome analysis shows that the single hat mutants are not very different from wild type. However, the comparison of the hat1 and hat2 transcriptomes shows that they are different. The hat1hat2 double mutant shows a transcriptional phenotype similar to that of the hat1 mutant but strongly enhanced. These results indicate that Hat2p could have additional functions in the cell to those of Hat1p. PMID:16023114

Rosaleny, Lorena E; Antúnez, Oreto; Ruiz-García, Ana B; Pérez-Ortín, José E; Tordera, Vicente

2005-08-01

206

Life spans of a Bellman-Harris branching process with immigration  

SciTech Connect

One considers two schemes of the Bellman-Harris process with immigration when a) the lifetime of the particles is an integral-valued random variable and the immigration is defined by a sequence of independent random variables; b) the distribution of the lifetime of the particles is nonlattice and the immigration is a process with continuous time. One investigates the properties of the life spans of such processes. The results obtained here are a generalization to the case of Bellman-Harris processes of the results of A.M. Zubkov, obtained for Markov branching processes. For the proof one makes use in an essential manner of the known inequalities of Goldstein, estimating the generating function of the Bellman-Harris process in terms of the generating functions of the imbedded Galton-Watson process.

Badalbaev, I.S.; Mashrabbaev, A.

1987-09-10

207

Independence of age-related influences on cognitive abilities across the life span.  

PubMed

Age-related increases in childhood and age-related decreases in adulthood have been reported for a wide variety of cognitive variables, but relatively little research has addressed the question of the independence of these influences. In this project, cross-sectional life span data (age 5 to 94 years) from the nationally representative sample used to establish the norms for the Woodcock-Johnson Psycho-Educational Battery (R. W. Woodcock & M. B. Johnson, 1989, 1990) were subjected to several types of analyses. The results indicated that the majority of age-related differences appear to be shared across different cognitive variables and are well predicted by individual differences in higher order factors. These findings suggest that the role of task-specific interpretations of developmental differences in cognition needs to be reevaluated to take into consideration the lack of independence of age-related influences on a variety of cognitive variables. PMID:9779733

Salthouse, T A

1998-09-01

208

Life span alteration after irradiation in Drosophila melanogaster strains with mutations of Hsf and Hsps  

Microsoft Academic Search

The life span alteration after ?-irradiation and\\/or paraquat treatment in Drosophila in wild type strain Canton-S and strains with mutations of heat shock factor (1–4 alleles) and heat shock proteins (Hsp70Ba\\u000a \\u000a 304\\u000a , Hsp83\\u000a \\u000a e6A\\u000a , Hsp22\\u000a \\u000a EY09909\\u000a , Hsp67Bb\\u000a \\u000a EY099099\\u000a ) was investigated. Chronic low-dose rate ?-irradiation (0.017 and 0.17 cGy\\/h) on pre-imago stages was used as a priming dose

A. Moskalev; M. Shaposhnikov; E. Turysheva

2009-01-01

209

Invited commentary: missing doses in the life span study of Japanese atomic bomb survivors.  

PubMed

The Life Span Study is a long-term epidemiologic cohort study of survivors of the atomic bombs dropped on Hiroshima and Nagasaki, Japan. In this issue of the Journal, Richardson et al. (Am J Epidemiol. 2013;177(6):562-568) suggest that those who died in the earliest years of follow-up were more likely to have a missing dose of radiation exposure assigned, leading to a bias in the radiation risk estimates. We show that nearly all members of the cohort had shielding information recorded before the beginning of follow-up and that much of the alleged bias that Richardson et al. describe simply reflects the geographic distribution of shielding conditions for which reliable dosimetry was impossible. PMID:23429724

Ozasa, K; Grant, E J; Cullings, H M; Shore, R E

2013-02-20

210

Mitochondrial respiratory thresholds regulate yeast chronological life span and its extension by caloric restriction.  

PubMed

We have explored the role of mitochondrial function in aging by genetically and pharmacologically modifying yeast cellular respiration production during the exponential and/or stationary growth phases and determining how this affects chronological life span (CLS). Our results demonstrate that respiration is essential during both growth phases for standard CLS, but that yeast have a large respiratory capacity, and only deficiencies below a threshold (~40% of wild-type) significantly curtail CLS. Extension of CLS by caloric restriction also required respiration above a similar threshold during exponential growth and completely alleviated the need for respiration in the stationary phase. Finally, we show that supplementation of media with 1% trehalose, a storage carbohydrate, restores wild-type CLS to respiratory-null cells. We conclude that mitochondrial respiratory thresholds regulate yeast CLS and its extension by caloric restriction by increasing stress resistance, an important component of which is the optimal accumulation and mobilization of nutrient stores. PMID:22768839

Ocampo, Alejandro; Liu, Jingjing; Schroeder, Elizabeth A; Shadel, Gerald S; Barrientos, Antoni

2012-07-01

211

Leaf life span, dynamics and construction cost of species from Mediterranean old-fields differing in successional status  

Microsoft Academic Search

Summary • Variations in leaf life span (LLS), construction cost (CC) and dynamics patterns (periods of leaf production, t p , and loss, t L , time lag separating the end of leaf pro- duction and the beginning of leaf loss, t) were investigated in species differing in suc- cessional status and life forms. We tested how those traits varied

Marie-Laure Navas; Beatrice Ducout; Catherine Roumet; Jean Richarte; Joel Garnier; Eric Garnier

2003-01-01

212

Virtual navigation strategies from childhood to senescence: evidence for changes across the life span  

PubMed Central

This study sought to investigate navigational strategies across the life span, by testing 8-years old children to 80-years old healthy older adults on the 4 on 8 virtual maze (4/8VM). The 4/8VM was previously developed to assess spontaneous navigational strategies, i.e., hippocampal-dependent spatial strategies (navigation by memorizing relationships between landmarks) versus caudate nucleus-dependent response strategies (memorizing a series of left and right turns from a given starting position). With the 4/8VM, we previously demonstrated greater fMRI activity and gray matter in the hippocampus of spatial learners relative to response learners. A sample of 599 healthy participants was tested in the current study. Results showed that 84.4% of children, 46.3% of young adults, and 39.3% of older adults spontaneously used spatial strategies (p < 0.0001). Our results suggest that while children predominantly use spatial strategies, the proportion of participants using spatial strategies decreases across the life span, in favor of response strategies. Factors promoting response strategies include repetition, reward and stress. Since response strategies can result from successful repetition of a behavioral pattern, we propose that the increase in response strategies is a biological adaptive mechanism that allows for the automatization of behavior such as walking in order to free up hippocampal-dependent resources. However, the down-side of this shift from spatial to response strategies occurs if people stop building novel relationships, which occurs with repetition and routine, and thereby stop stimulating their hippocampus. Reduced fMRI activity and gray matter in the hippocampus were shown to correlate with cognitive deficits in normal aging. Therefore, these results have important implications regarding factors involved in healthy and successful aging.

Bohbot, Veronique D.; McKenzie, Sam; Konishi, Kyoko; Fouquet, Celine; Kurdi, Vanessa; Schachar, Russel; Boivin, Michel; Robaey, Philippe

2012-01-01

213

Closing the gap between T-cell life span estimates from stable isotope-labeling studies in mice and humans.  

PubMed

Quantitative knowledge of the turnover of different leukocyte populations is a key to our understanding of immune function in health and disease. Much progress has been made thanks to the introduction of stable isotope labeling, the state-of-the-art technique for in vivo quantification of cellular life spans. Yet, even leukocyte life span estimates on the basis of stable isotope labeling can vary up to 10-fold among laboratories. We investigated whether these differences could be the result of variances in the length of the labeling period among studies. To this end, we performed deuterated water-labeling experiments in mice, in which only the length of label administration was varied. The resulting life span estimates were indeed dependent on the length of the labeling period when the data were analyzed using a commonly used single-exponential model. We show that multiexponential models provide the necessary tool to obtain life span estimates that are independent of the length of the labeling period. Use of a multiexponential model enabled us to reduce the gap between human T-cell life span estimates from 2 previously published labeling studies. This provides an important step toward unambiguous understanding of leukocyte turnover in health and disease. PMID:23945154

Westera, Liset; Drylewicz, Julia; den Braber, Ineke; Mugwagwa, Tendai; van der Maas, Iris; Kwast, Lydia; Volman, Thomas; van de Weg-Schrijver, Elise H R; Bartha, István; Spierenburg, Gerrit; Gaiser, Koos; Ackermans, Mariëtte T; Asquith, Becca; de Boer, Rob J; Tesselaar, Kiki; Borghans, José A M

2013-08-14

214

Glucose shortens the life span of C. elegans by downregulating DAF-16/FOXO activity and aquaporin gene expression.  

PubMed

Many studies have addressed the effect of dietary glycemic index on obesity and diabetes, but little is known about its effect on life span itself. We found that adding a small amount of glucose to the medium (2%) shortened the life span of C. elegans by inhibiting the activities of life span-extending transcription factors that are also inhibited by insulin signaling: the FOXO family member DAF-16 and the heat shock factor HSF-1. This effect involved the downregulation of an aquaporin glycerol channel, aqp-1. We show that changes in glycerol metabolism are likely to underlie the life span-shortening effect of glucose and that aqp-1 may act cell nonautonomously as a feedback regulator in the insulin/IGF-1-signaling pathway. Insulin downregulates similar glycerol channels in mammals, suggesting that this glucose-responsive pathway might be conserved evolutionarily. Together, these findings raise the possibility that a low-sugar diet might have beneficial effects on life span in higher organisms. PMID:19883616

Lee, Seung-Jae; Murphy, Coleen T; Kenyon, Cynthia

2009-11-01

215

Role of cellular mechanics in the function and life span of vascular endothelium.  

PubMed

The vascular endothelium plays a crucial role in vessel homeostasis and is implicated in the pathogenesis of cardiovascular disease. The function and life span of endothelial cells, therefore, have a large impact upon the quality and expectancy of an individual's life. Exposure to haemodynamic forces determines the phenotype of endothelial cells. Turbulent blood flow, disturbed shear stress and a rising tension of the vessel wall result in endothelial dysfunction and an enhanced endothelial cell turnover. In this scenario, the role of endothelial mechanics is yet poorly described. The streaming blood exerts shear forces transmitted to the soft cortical actin mesh immediately underneath the plasma membrane. The mechanical properties of this actin cortex seem to be an important regulator of endothelial function. Aldosterone and high plasma sodium stiffen the endothelial cell cortex which is accompanied by a decrease in NO release. If endothelial stiffening is only transient, it may be a useful mechanism to compensate for any decrease in arterial blood pressure. Long-term stiffening of the cell, however, may lead to endothelial dysfunction and may contribute to cardiovascular disorders, as observed in disturbed aldosterone/sodium homeostasis. In this case, the mineralocorticoid receptor antagonist spironolactone maintains the endothelial cell cortex soft and thereby preserves normal endothelial function and longevity. This may explain the recently observed beneficial effects of spironolactone on the cardiovascular system. Taken together, the review highlights the importance of elasticity for normal endothelial function. PMID:21318292

Kliche, Katrin; Jeggle, Pia; Pavenstädt, Hermann; Oberleithner, Hans

2011-02-12

216

The activity-dependent histone variant H2BE modulates the life span of olfactory neurons  

PubMed Central

We have identified a replication-independent histone variant, Hist2h2be (referred to herein as H2be), which is expressed exclusively by olfactory chemosensory neurons. Levels of H2BE are heterogeneous among olfactory neurons, but stereotyped according to the identity of the co-expressed olfactory receptor (OR). Gain- and loss-of-function experiments demonstrate that changes in H2be expression affect olfactory function and OR representation in the adult olfactory epithelium. We show that H2BE expression is reduced by sensory activity and that it promotes neuronal cell death, such that inactive olfactory neurons display higher levels of the variant and shorter life spans. Post-translational modifications (PTMs) of H2BE differ from those of the canonical H2B, consistent with a role for H2BE in altering transcription. We propose a physiological function for H2be in modulating olfactory neuron population dynamics to adapt the OR repertoire to the environment. DOI: http://dx.doi.org/10.7554/eLife.00070.001

Santoro, Stephen W; Dulac, Catherine

2012-01-01

217

Control of protein life-span by N-terminal methionine excision  

PubMed Central

Peptide deformylases (PDFs) have been discovered recently in eukaryotic genomes, and it appears that N-terminal methionine excision (NME) is a conserved pathway in all compartments where protein synthesis occurs. This work aimed at uncovering the function(s) of NME in a whole proteome, using the chloroplast-encoded proteins of both Arabidopsis thaliana and Chlamydomonas reinhardtii as model systems. Dis ruption of PDF1B in A.thaliana led to an albino phenotype, and an extreme sensitivity to the PDF- specific inhibitor actinonin. In contrast, a knockout line for PDF1A exhibited no apparent phenotype. Photosystem II activity in C.reinhardtii cells was substantially reduced by the presence of actinonin. Pulse–chase experiments revealed that PDF inhibi tion leads to destabilization of a crucial subset of chloroplast-encoded photosystem II components in C.reinhardtii. The same proteins were destabilized in pdf1b. Site-directed substitutions altering NME of the most sensitive target, subunit D2, resulted in similar effects. Thus, plastid NME is a critical mechanism specifically influencing the life-span of photosystem II polypeptides. A general role of NME in modulating the half-life of key subsets of proteins is suggested.

Giglione, Carmela; Vallon, Olivier; Meinnel, Thierry

2003-01-01

218

Everyday problem solving across the adult life span: solution diversity and efficacy  

PubMed Central

Everyday problem solving involves examining the solutions that individuals generate when faced with problems that take place in their everyday experiences. Problems can range from medication adherence and meal preparation to disagreeing with a physician over a recommended medical procedure or compromising with extended family members over where to host Thanksgiving dinner. Across the life span, research has demonstrated divergent patterns of change in performance based on the type of everyday problems used as well as based on the way that problem-solving efficacy is operationally defined. Advancing age is associated with worsening performance when tasks involve single-solution or fluency-based definitions of effectiveness. However, when efficacy is defined in terms of the diversity of strategies used, as well as by the social and emotional impact of solution choice on the individual, performance is remarkably stable and sometimes even improves in the latter half of life. This article discusses how both of these approaches to everyday problem solving inform research on the influence that aging has on everyday functioning.

Mienaltowski, Andrew

2013-01-01

219

Everyday problem solving across the adult life span: solution diversity and efficacy.  

PubMed

Everyday problem solving involves examining the solutions that individuals generate when faced with problems that take place in their everyday experiences. Problems can range from medication adherence and meal preparation to disagreeing with a physician over a recommended medical procedure or compromising with extended family members over where to host Thanksgiving dinner. Across the life span, research has demonstrated divergent patterns of change in performance based on the type of everyday problems used as well as based on the way that problem-solving efficacy is operationally defined. Advancing age is associated with worsening performance when tasks involve single-solution or fluency-based definitions of effectiveness. However, when efficacy is defined in terms of the diversity of strategies used, as well as by the social and emotional impact of solution choice on the individual, performance is remarkably stable and sometimes even improves in the latter half of life. This article discusses how both of these approaches to everyday problem solving inform research on the influence that aging has on everyday functioning. PMID:22023569

Mienaltowski, Andrew

2011-10-01

220

Radiation effects on cancer risks in the Life Span Study cohort.  

PubMed

To determine late health effects of radiation in atomic bomb survivors, the Radiation Effects Research Foundation has been conducting studies on the Life Span Study (LSS) population, which consists of 93,000 atomic bomb survivors and 27,000 controls. A recent report on the incidence of solid cancers estimates that at the age of 70 y, after exposure at the age of 30 y, solid-cancer rates increase by about 35% per Gy for men and 58% per Gy for women. The age-at-exposure is an important risk modifier. Furthermore, it seems that radiation-associated increases in cancer rates persist throughout life. In addition, radiation has similar effects upon first-primary and second-primary cancer risks. A recent report on leukemia mortality suggested that the effect of radiation on leukemia mortality persisted for more than five decades. In addition, a significant dose-response for myelodysplastic syndrome is found in Nagasaki LSS members 40-60 y after radiation exposure. In view of the nature of the continuing increase in solid cancers, the LSS should continue to provide important new information on cancer risks, as most survivors still alive today were exposed to the atomic bomb radiation under the age of 20 y and are now entering their cancer-prone years. PMID:22908358

Kodama, Kazunori; Ozasa, Kotaro; Katayama, Hiroaki; Shore, Roy E; Okubo, Toshiteru

2012-08-19

221

Starting early: promoting the mental health of women and girls throughout the life span.  

PubMed

The importance of mental health in the promotion of lifelong health among men and women alike cannot be overstated. However, mental health remains under-addressed within general public health and community health programs. In this report, we focus primarily on the mental health of women and discuss risk factors that can affect the well-being of women throughout the life span. The literature reviewed demonstrates a strong relationship between social and environmental risk factors, such as abuse and family dysfunction in childhood, to health risk behaviors and poor mental health in adulthood. We concluded that adverse childhood experiences (ACEs) and poor adult mental health could contribute to cycles of intergenerational transmission of risks leading to poor mental and physical health in children of ACEexposed parents. Also, we argue that public health communities can make a difference in women's lifelong health by improving early recognition and treatment of mental health concerns, seeking opportunities to prevent exposures to known risk factors in childhood, and developing targeted parenting interventions. Promoting healthy psychological states and coping mechanisms before, during, and after exposure to adverse events throughout life is also critical. Perhaps such efforts will help to reduce or even break cycles of risk exposure specifically for women and their children. Finally, existing prevention activities and opportunities for promoting the mental health of girls and women are discussed. Ultimately, this report challenges the women's health and public health communities to take action because mental health can have a serious impact on lifelong well-being. PMID:16313205

Lesesne, Catherine A; Kennedy, Christine

2005-11-01

222

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

PubMed

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. PMID:19783783

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

2009-09-25

223

Evolution of reproductive life histories in island birds worldwide  

PubMed Central

Island environments typically share characteristics such as impoverished biotas and less-seasonal climates, which should be conducive to specific adaptations by organisms. However, with the exception of morphological studies, broad-scale tests of patterns of adaptation on islands are rare. Here, I examine reproductive patterns in island birds worldwide. Reproductive life histories are influenced by latitude, which could affect the response to insularity; therefore, I additionally test this hypothesis. Island colonizers showed mostly bi-parental care, but there was a significant increase in cooperative breeding on islands. Additionally, I found support for previous suggestions of reduced fecundity, longer developmental periods and increased investment in young on islands. However, clutch size increased with latitude at a rate nearly five times faster on the mainland than on the islands revealing a substantially stronger effect of insularity at higher latitudes. Latitude and insularity may also interact to determine egg volume and incubation periods, but these effects were less clear. Analyses of reproductive success did not support an effect of reduced nest predation as a driver of reproductive change, but this requires further study. The effect of latitude detected here suggests that the evolutionary changes associated with insularity relate to environmental stability and improved adult survival.

Covas, Rita

2012-01-01

224

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

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…

Boerner, Kathrin; Jopp, Daniela

2007-01-01

225

Retention of high tactile acuity throughout the life span in blindness.  

PubMed

Previous studies of tactile acuity on the fingertip, using passive touch, have demonstrated an age-related decline in spatial resolution for both sighted and blind subjects. We have reexamined this age dependence with two newly designed tactile-acuity charts that require active exploration of the test symbols. One chart used dot patterns similar to braille, and the other used embossed Landolt rings. Groups of blind braille readers and sighted subjects ranging from 12 to 85 years old were tested in two experiments. We replicated previous findings for sighted subjects by showing an age-related decrease in tactile acuity by nearly 1% per year. Surprisingly, the blind subjects retained high acuity into old age, showing no age-related decline. For the blind subjects, tactile acuity did not correlate with braille reading speed, the amount of daily reading, or the age at which braille was learned. We conclude that when measured with active touch, blind subjects retain high tactile acuity into old age, unlike their aging sighted peers. We propose that blind people's use of active touch in daily activities, not specifically braille reading, results in preservation of tactile acuity across the life span. PMID:19064491

Legge, Gordon E; Madison, Cindee; Vaughn, Brenna N; Cheong, Allen M Y; Miller, Joseph C

2008-11-01

226

A fasting-responsive signaling pathway that extends life span in C. elegans.  

PubMed

Intermittent fasting is one of the most effective dietary restriction regimens that extend life span in C. elegans and mammals. Fasting-stimulus responses are key to the longevity response; however, the mechanisms that sense and transduce the fasting stimulus remain largely unknown. Through a comprehensive transcriptome analysis in C. elegans, we find that along with the FOXO transcription factor DAF-16, AP-1 (JUN-1/FOS-1) plays a central role in fasting-induced transcriptional changes. KGB-1, one of the C. elegans JNKs, acts as an activator of AP-1 and is activated in response to fasting. KGB-1 and AP-1 are involved in intermittent fasting-induced longevity. Fasting-induced upregulation of the components of the SCF E3 ubiquitin ligase complex via AP-1 and DAF-16 enhances protein ubiquitination and reduces protein carbonylation. Our results thus identify a fasting-responsive KGB-1/AP-1 signaling pathway, which, together with DAF-16, causes transcriptional changes that mediate longevity, partly through regulating proteostasis. PMID:23352664

Uno, Masaharu; Honjoh, Sakiko; Matsuda, Mitsuhiro; Hoshikawa, Haruka; Kishimoto, Saya; Yamamoto, Tomohito; Ebisuya, Miki; Yamamoto, Takuya; Matsumoto, Kunihiro; Nishida, Eisuke

2013-01-24

227

The decline of verbal and visuospatial working memory across the adult life span.  

PubMed

It has been well established that working memory abilities decrease with advancing age; however, the specific time point in the adult life span at which this deficit begins and the rate at which it advances are still controversial. There is no agreement on whether working memory declines equally for visuospatial and verbal information, and the literature disagrees on how task difficulty may influence this decay. We addressed these questions in a lifespan sample of 1,500 participants between 21 and 80 years old. The n-back task was used, with letters and circles presented at different positions around an imaginary circle, to evaluate working memory in the verbal and visuospatial domains, respectively. The participants' task was to judge whether the current stimulus matched a stimulus that was shown n trials prior. Both domains were evaluated in two levels of difficulty: 1-back and 2-back. The comparison across decades showed that discrimination in the visuospatial and 1-back tasks started to decline earlier in women than in men; however, discrimination was equal between the sexes in the verbal and 2-back tasks. Performance on tasks in the visuospatial domain exhibited more pronounced decline than in those in the verbal domain. The rate of decline in working memory accuracy was superior in 2-back tasks than in 1-back tasks, independent of the domain. These results revealed that the effects of aging on working memory are less dependent on the type of information and more reliant on the resources demanded by the task. PMID:23558670

Cansino, Selene; Hernández-Ramos, Evelia; Estrada-Manilla, Cinthya; Torres-Trejo, Frine; Martínez-Galindo, Joyce Graciela; Ayala-Hernández, Mariana; Gómez-Fernández, Tania; Osorio, David; Cedillo-Tinoco, Melisa; Garcés-Flores, Lissete; Beltrán-Palacios, Karla; García-Lázaro, Haydée Guadalupe; García-Gutiérrez, Fabiola; Cadena-Arenas, Yadira; Fernández-Apan, Luisa; Bärtschi, Andrea; Rodríguez-Ortiz, María Dolores

2013-04-05

228

[Interpopulation and sex-specific life span differences in human populations and their modeling in Drosophila].  

PubMed

Significant interpopulation and sex-specific longevity differences among human populations appear enigmatic biodemographic phenomenon. We modeled this problem in Drosophila studying the life span (LS) differences among six stocks isolated from geographically distant European and middle Asian populations and two standard laboratory lines. The survival rate dynamics, male/female mortality profiles (SR) and their variability were compared in optimal (25 degrees C) and stress temperature conditions (29 degrees C). Two old laboratory stocks Canton S and Oregon R manifested drastic differences in LS and SR rate (0,48 for Canton S and 0,86 for Oregon R). Six population stocks grown in normal conditions demonstrated similar differences: from relatively high female and male longevity (Kirgizia and Altay mountain populations) to short living stock (Tashkent). SR rate also manifested significant variations (from 0,79 up to 1,18). Evidently population studied differed on concentration of genes responsible for significant LS and SR differences. Stress temperature maintenance (29 degrees C) twice as decreased the longevity of all studied stocks however remaining interstock LS ranges. At the same time the action of genes which induced in optimal conditions SR differences was partly suppressed under stress conditions. Our genetic/population model data give possibility to predict a possible spectrum of LS and SR genetic variations in human populations and level of their stability under stress. PMID:24003730

2013-01-01

229

Expected value information improves financial risk taking across the adult life span  

PubMed Central

When making decisions, individuals must often compensate for cognitive limitations, particularly in the face of advanced age. Recent findings suggest that age-related variability in striatal activity may increase financial risk-taking mistakes in older adults. In two studies, we sought to further characterize neural contributions to optimal financial risk taking and to determine whether decision aids could improve financial risk taking. In Study 1, neuroimaging analyses revealed that individuals whose mesolimbic activation correlated with the expected value estimates of a rational actor made more optimal financial decisions. In Study 2, presentation of expected value information improved decision making in both younger and older adults, but the addition of a distracting secondary task had little impact on decision quality. Remarkably, provision of expected value information improved the performance of older adults to match that of younger adults at baseline. These findings are consistent with the notion that mesolimbic circuits play a critical role in optimal choice, and imply that providing simplified information about expected value may improve financial risk taking across the adult life span.

Wagner, Anthony D.; Knutson, Brian

2011-01-01

230

?-N-Methylamino-L-alanine Induces Neurological Deficits and Shortened Life Span in Drosophila  

PubMed Central

The neurotoxic non-protein amino acid, ?-N-methylamino-L-alanine (BMAA), was first associated with the high incidence of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia Complex (ALS/PDC) in Guam. Recently, BMAA has been implicated as a fierce environmental factor that contributes to the etiology of Alzheimer’s and Parkinson’s diseases, in addition to ALS. However, the toxicity of BMAA in vivo has not been clearly demonstrated. Here we report our investigation of the neurotoxicity of BMAA in Drosophila. We found that dietary intake of BMAA reduced life span, locomotor functions, and learning and memory abilities in flies. The severity of the alterations in phenotype is correlated with the concentration of BMAA detected in flies. Interestingly, developmental exposure to BMAA had limited impact on survival rate, but reduced fertility in females, and caused delayed neurological impairment in aged adults. Our studies indicate that BMAA exposure causes chronic neurotoxicity, and that Drosophila serves as a useful model in dissecting the pathogenesis of ALS/PDC.

Zhou, Xianchong; Escala, Wilfredo; Papapetropoulos, Spyridon; Zhai, R. Grace

2010-01-01

231

Atrx deficiency induces telomere dysfunction, endocrine defects, and reduced life span  

PubMed Central

Human ATRX mutations are associated with cognitive deficits, developmental abnormalities, and cancer. We show that the Atrx-null embryonic mouse brain accumulates replicative damage at telomeres and pericentromeric heterochromatin, which is exacerbated by loss of p53 and linked to ATM activation. ATRX-deficient neuroprogenitors exhibited higher incidence of telomere fusions and increased sensitivity to replication stress–inducing drugs. Treatment of Atrx-null neuroprogenitors with the G-quadruplex (G4) ligand telomestatin increased DNA damage, indicating that ATRX likely aids in the replication of telomeric G4-DNA structures. Unexpectedly, mutant mice displayed reduced growth, shortened life span, lordokyphosis, cataracts, heart enlargement, and hypoglycemia, as well as reduction of mineral bone density, trabecular bone content, and subcutaneous fat. We show that a subset of these defects can be attributed to loss of ATRX in the embryonic anterior pituitary that resulted in low circulating levels of thyroxine and IGF-1. Our findings suggest that loss of ATRX increases DNA damage locally in the forebrain and anterior pituitary and causes tissue attrition and other systemic defects similar to those seen in aging.

Watson, L. Ashley; Solomon, Lauren A.; Li, Jennifer Ruizhe; Jiang, Yan; Edwards, Matthew; Shin-ya, Kazuo; Beier, Frank; Berube, Nathalie G.

2013-01-01

232

Proteomic profiles reveal age-related changes in coelomic fluid of sea urchin species with different life spans.  

PubMed

Sea urchins have a different life history from humans and traditional model organisms used to study the process of aging. Sea urchins grow indeterminately, reproduce throughout their life span and some species have been shown to exhibit negligible senescence with no increase in mortality rate at advanced ages. Despite these properties, different species of sea urchins are reported to have very different natural life spans providing a unique model to investigate cellular mechanisms underlying life span determination and negligible senescence. To gain insight into the biological changes that accompany aging in these animals, proteomic profiles were examined in coelomic fluid from young and old sea urchins of three species with different life spans: short-lived Lytechinus variegatus, long-lived Strongylocentrotus franciscanus and Strongylocentrotus purpuratus which has an intermediate life span. The proteomic profiles of cell-free coelomic fluid were complex with many proteins exhibiting different forms and extensive post-translational modifications. Approximately 20% of the protein spots on 2-D gels showed more than two-fold change with age in each of the species. Changes that are consistent with age in all three species may prove to be useful biomarkers for age-determination for these commercially fished marine invertebrates and also may provide clues to mechanisms of negligible senescence. Among the proteins that change with age, the ectodomain of low-density lipoprotein receptor-related protein 4 (LRP4) was significantly increased in the coelomic fluid of all three sea urchin species suggesting that the Wnt signaling pathway should be further investigated for its role in negligible senescence. PMID:23453931

Bodnar, Andrea

2013-02-08

233

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

PubMed Central

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.—Park, S.-K., Link, C. D., Johnson, T. E. Life-span extension by dietary restriction is mediated by NLP-7 signaling and coelomocyte endocytosis in C. elegans.

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

2010-01-01

234

LINEAR ALLOMETRIC RELATIONSHIP BETWEEN TOTAL METABOLIC ENERGY PER LIFE SPAN AND BODY MASS OF TERRESTRIAL MAMMALS IN CAPTIVITY  

Microsoft Academic Search

Summary Atanasov, A.T., 2006. Linear allometric relationship between total metabolic energy per life span and body mass of terrestrial mammals in captivity. Bulg. J. Vet. Med. , 9, No 3, 159 ?174. The bioenergetic studies on animals have shown that basal metabolic rate P (kJ\\/d), is related to the body mass M (kg) of animals as expressed by the equation:

A. T. Atanasov

2006-01-01

235

Age and calorie-independent life span extension from dietary restriction by bacterial deprivation in Caenorhabditis elegans  

Microsoft Academic Search

BACKGROUND: Dietary restriction (DR) increases life span and delays age-associated disease in many organisms. The mechanism by which DR enhances longevity is not well understood. RESULTS: Using bacterial food deprivation as a means of DR in C. elegans, we show that transient DR confers long-term benefits including stress resistance and increased longevity. Consistent with studies in the fruit fly and

Erica D Smith; Tammi L Kaeberlein; Brynn T Lydum; Jennifer Sager; K Linnea Welton; Brian K Kennedy; Matt Kaeberlein

2008-01-01

236

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

ERIC Educational Resources Information Center

|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…

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

2011-01-01

237

Effect of Long-Term Somatotropin Treatment on Body Composition and Life Span in Aging Obese Zucker Rats  

Microsoft Academic Search

The objective of this work was to test the hypothesis that a somatotropin (STH)-induced reduction in body fat would pro- long the life span of the obese Zucker rat. Two experiments were conducted. In the first experiment, male and female, lean and obese Zucker rats were treated with STH (0 or 2 mg\\/d bovine STH) for 4 weeks, beginning at

MICHAEL J. AZAIN; J. ROGER BRODERSON; ROY J. MARTIN

238

EAS Temperaments During the Last Half of the Life Span: Twins Reared Apart and Twins Reared Together  

Microsoft Academic Search

In this first behavioral genetic study of personality in the last half of the life span, results are reported using the powerful adoption\\/twin design that compares identical and fraternal twins reared apart and identical and fraternal twins reared together. Traits studied were the EAS temperaments (emotionality, activity level, and sociability), traits that show substantial genetic influence in childhood. It was

Robert Plomin; Nancy L. Pedersen; G. E. McClearn; John R. Nesselroade; C. S. Bergeman

1988-01-01

239

The relationship of cancer mortality to life span and food supply rate  

SciTech Connect

Survival curves for men and women dying from cardiovascular disease and similar curves for those dying from cancer in 47 countries were compared with the 1970-1974 per capita incomes of the inhabitants. The data were taken chiefly from 1964 life tables. The steepest survival curves were found in countries with the highest incomes. Comparison of the survival curves in different countries and comparison of cardiovascular survival with cancer survival curves indicate that both groups of diseases are probably diseases of senescence. The differences in survival slopes are interpreted as homeostatic responses in the population to rate of food intake. The response protects the population against long-term effects of changes in food supply by promoting differential reproduction of offspring best suited to the food supply rate fro the environment. The response to food supply rate complicates calculation of the effects of protracted exposure to low-level ionizing radiation because the radiation exposure appears to mimic the effec of extra food.

Totter, J.R.; Adler, H.I.; Storer, J.B.

1985-08-01

240

Comparing plant life histories using elasticity analysis: the importance of life span and the number of life-cycle stages  

Microsoft Academic Search

Recent studies have used transition matrix elasticity analysis to investigate the relative role of survival (L), growth (G) and fecundity (F) in determining the estimated rate of population increase for perennial plants. The relative importance of these three variables has then been used as a framework for comparing patterns of plant life history in a triangular parameter space. Here we

N. J. Enright; M. Franco; J. Silvertown

1995-01-01

241

The Genetic Architecture of Life Span and Mortality Rates: Gender and Species Differences in Inbreeding Load of Two Seed-Feeding Beetles  

PubMed Central

We examine the inbreeding load for adult life span and mortality rates of two seed beetle species, Callosobruchus maculatus and Stator limbatus. Inbreeding load differs substantially between males and females in both study populations of C. maculatus—life span of inbred females was 9–13% shorter than the life span of outbred females, whereas the life span of inbred males did not differ from the life span of outbred males. The effect of inbreeding on female life span was largely due to an increase in the slope of the mortality curve. In contrast, inbreeding had only a small effect on the life span of S. limbatus—life spans of inbred beetles were ?5% shorter than those of outbred beetles, and there was no difference in inbreeding load between the sexes. The inbreeding load for mean life span was ?0.4–0.6 lethal equivalents per haploid gamete for female C. maculatus and ?0.2–0.3 for both males and females of S. limbatus, all within the range of estimates commonly obtained for Drosophila. However, contrary to the predictions of mutation-accumulation models, inbreeding load for loci affecting mortality rates did not increase with age in either species, despite an effect of inbreeding on the initial rate of increase in mortality. This was because mortality rates decelerated with age and converged to a mortality plateau for both outbred and inbred beetles.

Fox, Charles W.; Scheibly, Kristy L.; Wallin, William G.; Hitchcock, Lisa J.; Stillwell, R. Craig; Smith, Benjamin P.

2006-01-01

242

Generation and Characterization of Telomerase-Transfected Human Lymphatic Endothelial Cells with an Extended Life Span  

PubMed Central

The study of lymphatic endothelial cells and lymphangiogenesis has, in the past, been hampered by the lack of lymphatic endothelial-specific markers. The recent discovery of several such markers has permitted the isolation of lymphatic endothelial cells (LECs) from human skin. However, cell numbers are limited and purity is variable with the different isolation procedures. To overcome these problems, we have transfected human dermal microvascular endothelial cells (HDMVECs) with a retrovirus containing the coding region of human telomerase reverse transcriptase (hTERT), and have produced a cell line, hTERT-HDLEC, with an extended lifespan. hTERT-HDLEC exhibit a typical cobblestone morphology when grown in culture, are contact-inhibited, and express endothelial cell-specific markers. hTERT-HDLEC also express the recognized lymphatic markers, Prox-1, LYVE-1 and podoplanin, as well as integrin ?9, but do not express CD34. They also form tube-like structures in three-dimensional collagen gels when stimulated with vascular endothelial growth factors -A and -C. Based on these currently recognized criteria, these cells are LEC. Surprisingly, we also found that the widely studied HMEC-1 cell line expresses recognized lymphatic markers; however, these cells are also CD34-positive. In summary, the ectopic expression of hTERT increases the life span of LECs and does not affect their capacity to form tube-like structures in a collagen matrix. The production and characterization of hTERT-HDLEC will facilitate the study of the properties of lymphatic endothelium in vitro.

Nisato, Riccardo E.; Harrison, Jillian A.; Buser, Raphaele; Orci, Lelio; Rinsch, Chris; Montesano, Roberto; Dupraz, Philippe; Pepper, Michael S.

2004-01-01

243

Missing doses in the life span study of Japanese atomic bomb survivors.  

PubMed

The Life Span Study of atomic bomb survivors is an important source of risk estimates used to inform radiation protection and compensation. Interviews with survivors in the 1950s and 1960s provided information needed to estimate radiation doses for survivors proximal to ground zero. Because of a lack of interview or the complexity of shielding, doses are missing for 7,058 of the 68,119 proximal survivors. Recent analyses excluded people with missing doses, and despite the protracted collection of interview information necessary to estimate some survivors' doses, defined start of follow-up as October 1, 1950, for everyone. We describe the prevalence of missing doses and its association with mortality, distance from hypocenter, city, age, and sex. Missing doses were more common among Nagasaki residents than among Hiroshima residents (prevalence ratio = 2.05; 95% confidence interval: 1.96, 2.14), among people who were closer to ground zero than among those who were far from it, among people who were younger at enrollment than among those who were older, and among males than among females (prevalence ratio = 1.22; 95% confidence interval: 1.17, 1.28). Missing dose was associated with all-cancer and leukemia mortality, particularly during the first years of follow-up (all-cancer rate ratio = 2.16, 95% confidence interval: 1.51, 3.08; and leukemia rate ratio = 4.28, 95% confidence interval: 1.72, 10.67). Accounting for missing dose and late entry should reduce bias in estimated dose-mortality associations. PMID:23429722

Richardson, David B; Wing, Steve; Cole, Stephen R

2013-02-20

244

Generation and characterization of telomerase-transfected human lymphatic endothelial cells with an extended life span.  

PubMed

The study of lymphatic endothelial cells and lymphangiogenesis has, in the past, been hampered by the lack of lymphatic endothelial-specific markers. The recent discovery of several such markers has permitted the isolation of lymphatic endothelial cells (LECs) from human skin. However, cell numbers are limited and purity is variable with the different isolation procedures. To overcome these problems, we have transfected human dermal microvascular endothelial cells (HDMVECs) with a retrovirus containing the coding region of human telomerase reverse transcriptase (hTERT), and have produced a cell line, hTERT-HDLEC, with an extended lifespan. hTERT-HDLEC exhibit a typical cobblestone morphology when grown in culture, are contact-inhibited, and express endothelial cell-specific markers. hTERT-HDLEC also express the recognized lymphatic markers, Prox-1, LYVE-1 and podoplanin, as well as integrin alpha9, but do not express CD34. They also form tube-like structures in three-dimensional collagen gels when stimulated with vascular endothelial growth factors -A and -C. Based on these currently recognized criteria, these cells are LEC. Surprisingly, we also found that the widely studied HMEC-1 cell line expresses recognized lymphatic markers; however, these cells are also CD34-positive. In summary, the ectopic expression of hTERT increases the life span of LECs and does not affect their capacity to form tube-like structures in a collagen matrix. The production and characterization of hTERT-HDLEC will facilitate the study of the properties of lymphatic endothelium in vitro. PMID:15215158

Nisato, Riccardo E; Harrison, Jillian A; Buser, Raphaele; Orci, Lelio; Rinsch, Chris; Montesano, Roberto; Dupraz, Philippe; Pepper, Michael S

2004-07-01

245

Auditory Brainstem Response (ABR) Abnormalities across the Life Span of Rats Prenatally Exposed to Alcohol  

PubMed Central

Background Fetal Alcohol Syndrome is a leading cause of neurodevelopmental impairments (NDI) in developed countries. Sensory deficits can play a major role in NDI, yet few studies have investigated the effects of prenatal alcohol exposure on sensory function. In addition, there is a paucity of information on the life-long effects of prenatal alcohol exposure. Thus, we sought to investigate the effects of prenatal alcohol exposure on auditory function across the life span in an animal model. Based on prior findings with prenatal alcohol exposure and other forms of adverse prenatal environments, we hypothesized that animals prenatally exposed to alcohol would show an age-dependent pattern of (A) hearing and neurological abnormalities as post-weanling pups, (B) a substantial dissipation of such abnormalities in young adulthood, and (C) a resurgence of such abnormalities in middle-aged adulthood. Method Pregnant rats were randomly assigned to an untreated control (CON), a pair-fed control (PFC) or an alcohol treated group (ALC). The ALC dams were gavaged with 6 mg/kg alcohol daily from gestation day (GD) 6 to 21. The PFC dams were gavaged daily from GD6-21 with an isocaloric and isovolumetric water-based solution of Maltose-Dextrins and pair-fed to the ALC dams. The CON dams were the untreated group to which the ALC and CON groups were compared. Hearing and neurological functions in the offspring were assessed with the Auditory Brainstem Response (ABR) at the postnatal ages of 22, 220 and 520 days of age. Results & Conclusions In accord with our hypothesis, ABR abnormalities were first observed in the post-weanling pups, largely dissipated in young adulthood, and then resurged in middle-aged adulthood. This age-related pattern suggests that the ALC pups had a developmental delay that dissipated in young adulthood and an enhanced age-related deterioration that occurred in middle-aged adulthood. Such a pattern is consistent with the fetal programming hypothesis of adult-onset diseases (the Barker Hypothesis). Our findings have important clinical implications for the assessment and management of (A) childhood hearing disorders and their co-morbidities (i.e., speech-and-language, learning, and attention deficit disorders) and (B) enhanced age-related hearing and neurological degeneration in middle-aged adulthood that can result from prenatal alcohol exposure. We recommend hearing evaluation be a part of any long-term follow-up for FAS patients and patients exposed to any adverse prenatal environment.

Church, Michael W.; Hotra, John W.; Holmes, Pamela A.; Anumba, Jennifer I.; Jackson, Desmond A.; Adams, Brittany R.

2011-01-01

246

Biocultural Orchestration of Developmental Plasticity Across Levels: The Interplay of Biology and Culture in Shaping the Mind and Behavior Across the Life Span  

Microsoft Academic Search

The author reviews reemerging coconstructive conceptions of development and recent empirical findings of developmental plasticity at different levels spanning several fields of developmental and life sciences. A cross-level dynamic biocultural coconstructive framework is endorsed to understand cognitive and behavioral development across the life span. This framework integrates main conceptions of earlier views into a unifying frame, viewing the dynamics of

Shu-Chen Li

2003-01-01

247

Accelerated age-related decline in replicative life-span of Duchenne muscular dystrophy myoblasts: Implications for cell and gene therapy  

Microsoft Academic Search

An assessment of the replicative life-span of myoblasts is of fundamental importance in designing treatment strategies for Duchenne muscular dystrophy (DMD) based on cell or gene therapy. To ascertain myoblast life-span, or the total number of cell divisions of which a myoblast was capable, we serially passaged and counted the progeny of individual myoblasts until they senesced. We compared the

Cecelia Webster; Helen M. Blau

1990-01-01

248

Evidence for a life span-prolonging effect of a linear plasmid in a longevity mutant of Podospora anserina  

Microsoft Academic Search

The linear mitochondrial plasmid pAL2-1 of the long-lived mutant AL2 of Podospora anserina was demonstrated to be able to integrate into the high molecular weight mitochondrial DNA (mtDNA). Hybridization analysis and densitometric evaluation of the mitochondrial genome isolated from cultures of different ages revealed that the mtDNA is highly stable during the whole life span of the mutant. In addition,

J. Hermanns; A. Asseburg; H. D. Osiewacz

1994-01-01

249

Impact of a Disruption of a Pathway Delivering Copper to Mitochondria on Podospora anserina Metabolism and Life Span  

Microsoft Academic Search

A global depletion of cellular copper as the result of a deficiency in high-affinity copper uptake was previously shown to affect the phenotype and life span of the filamentous fungus Podospora anserina. We report here the construction of a strain in which the delivery of copper to complex IV of the mitochondrial respiratory chain is affected. This strain, PaCox17::ble, is

Stefan W. Stumpferl; Oliver Stephan; Heinz D. Osiewacz

2004-01-01

250

Plant phenology and life span influence soil pool dynamics: Bromus tectorum invasion of perennial C 3 –C 4 grass communities  

Microsoft Academic Search

In water-limited ecosystems, small rainfall events can have dramatic impacts on microbial activity and soil nutrient pools.\\u000a Plant community phenology and life span also affect soil resources by determining the timing and quantity of plant nutrient\\u000a uptake, storage, and release. Using the replacement of C3–C4 perennial grasses by the invasive annual grass Bromus tectorum as a case study, we investigated

Elizabeth Carol Adair; Ingrid C. Burke

2010-01-01

251

An approach to give prospective life-span of the copper\\/low-density-polyethylene nanocomposite intrauterine device  

Microsoft Academic Search

As a novel copper-containing intrauterine device (IUD), the prospective life-span of the copper\\/low-density-polyethylene (Cu\\/LDPE)\\u000a nanocomposite IUD is very important for the future clinical use and should be given in advance. Here a novel approach, cupric\\u000a ions accelerated release in diluted nitric acid solution and cupric ions concentration release in various volume of simulated\\u000a uterine solution (SUS), is reported to verify

Xianping XiaYing; Ying Tang; Changsheng Xie; Yun Wang; Shuizhou Cai; Changhong Zhu

2011-01-01

252

Influence of sources of dietary oils on the life span of stroke-prone spontaneously hypertensive rats  

Microsoft Academic Search

In recent studies, the life span of stroke-prone spontaneously hypertensive (SHRSP) rats was altered by a variety of dietary\\u000a fats. It was relatively shorter in rats fed canola oil as the sole source of fat. The present study was performed to find\\u000a out whether the fatty acid profile and the high content of sulfur compounds in canola oil could modulate

W. M. N. Ratnayake; L. Plouffe; R. Hollywood; M. R. L'Abbé; N. Hidiroglou; G. Sarwar; R. Mueller

2000-01-01

253

The Relationship Between Women's Body Satisfaction and Self-Image Across the Life Span: The Role of Cognitive Control  

Microsoft Academic Search

The authors examined the relationship between body dissatisfaction and self-image across the life span. A sample of 106 women between the ages of 20 and 65 years completed questionnaire measures of body dissatisfaction, body importance, cognitive control over the body, self-concept, and self-esteem. The authors found that body dissatisfaction and body importance did not differ among the groups of women

Jessica Webster; Marika Tiggemann

2003-01-01

254

Estimation of the Life Span of Red Blood Cells in the Growing Animal in Different Nutritional States  

Microsoft Academic Search

In this study the model of Shemin and Rittenberg for estimating the life span of red blood cells was extended so that non-steady-state conditions, exemplified by growth or changing physiological states, might be considered. The parameters were estimated by use of the modified Gauss-Newton method. The biological data that were used came from growing sheep in different physiological states with

MELVIN W. CARTER; GENNARD MATRONE; CARL METZLER

1965-01-01

255

The extended life span of Drosophila melanogaster eye-color (white and vermilion) mutants with impaired formation of kynurenine  

PubMed Central

Animal and human studies suggest that aging is associated with increased formation of kynurenine (KYN) from tryptophan (TRY). The rate-limiting factors of TRY–KYN metabolism are transmembrane transport of TRY, and activity of enzyme, TRY 2,3-dioxygenase (TDO2). Eye-color mutants, white (w1118) (impaired TRY transport) and vermilion (v48a and v2) (deficient TDO activity), were compared with wild-type Oregon-R (Ore-R) strain of Drosophila melanogaster. Female 1-day-old adult flies maintained on a standard medium, and acclimatized to 12-h light:12-h dark cycle were collected, and then regularly transferred to fresh medium every 3–4 days. The number of dead flies was recorded at the time of transfer. Forty flies were studied in each experimental group. The life span of w1118 (mean = 45.5 days), and v48a (mean = 47.6 days) and v2 (mean = 43.8 days), were significantly longer than of wild-type Ore-R flies (27.1 days) (p < 0.001, Logrank test). There were no differences in life span between w1118 and v48a and v2 mutants. Present results suggest that prolongation of life span may be associated with slow rate of KYN formation from TRY.

Oxenkrug, Gregory F.

2010-01-01

256

Adolescent girls' life aspirations and reproductive health in Nepal.  

PubMed

The study described in this paper takes a participatory and positive approach to improving adolescent reproductive health in a rural and urban community in Nepal. It shows that adolescent girls in these communities have dreams and aspirations for a better future and that adults acknowledge and support these ideals. However, social norms and institutions are restrictive, especially for girls, who are often unable to realise their hopes for continuing education, finding better-paid work or delaying marriage and childbearing, and this directly impacts reproductive outcomes. Insight into the broader context of adolescent girls' lives provides a valuable framework for designing positive programmatic actions which take as their entry point the disjuncture between girls' aspirations and realities. Interventions begun in these communities include youth clubs for safe social interaction and literacy classes; training of peer educators to teach life-skills, including for married adolescents; forums for parents, teachers and health service providers to discuss their own concerns and those of adolescents; and work with the community to design programmes that will contribute to greater financial independence and employment opportunities for adolescents. PMID:11468851

Mathur, S; Malhotra, A; Mehta, M

2001-05-01

257

The Structure of Working Memory Abilities across the Adult Life Span  

PubMed Central

The present study addresses three questions regarding age differences in working memory: (1) whether performance on complex span tasks decreases as a function of age at a faster rate than performance on simple span tasks; (2) whether spatial working memory decreases at a faster rate than verbal working memory; and (3) whether the structure of working memory abilities is different for different age groups. Adults, ages 20–89 (n=388), performed three simple and three complex verbal span tasks and three simple and three complex spatial memory tasks. Performance on the spatial tasks decreased at faster rates as a function of age than performance on the verbal tasks, but within each domain, performance on complex and simple span tasks decreased at the same rates. Confirmatory factor analyses revealed that domain-differentiated models yielded better fits than models involving domain-general constructs, providing further evidence of the need to distinguish verbal and spatial working memory abilities. Regardless of which domain-differentiated model was examined, and despite the faster rates of decrease in the spatial domain, age group comparisons revealed that the factor structure of working memory abilities was highly similar in younger and older adults and showed no evidence of age-related dedifferentiation.

Hale, Sandra; Rose, Nathan S.; Myerson, Joel; Strube, Michael J; Sommers, Mitchell; Tye-Murray, Nancy; Spehar, Brent

2010-01-01

258

dSir2 and Dmp53 interact to mediate aspects of CR-dependent life span extension in D. melanogaster  

PubMed Central

Calorie Restriction (CR) is a well established method of extending life span in a variety of organisms. In the fruit fly D. melanogaster, CR is mediated at least in part by activation of dSir2. In mammalian systems, one of the critical targets of Sir2 is the tumor suppressor p53. This deacetylation of p53 by Sir2 leads to inhibition of p53's transcriptional activity. We have recently shown that inhibition of Dmp53 activity in the fly brain through the use of dominant-negative (DN) constructs that inhibit DNA-binding can extend life span. This life span extension appears to be related to CR, as CR and DN-Dmp53 do not display additive effects on life span. Here we report that life span extension by DN-Dmp53 expression is highly dynamic and can be achieved even when DN-Dmp53 is expressed later in life. In addition, we demonstrate that life span extension by activation of dSir2 and DN-Dmp53 expression are not additive. Furthermore, we show that dSir2 physically interacts with Dmp53 and can deacetylate Dmp53-derived peptides. Taken together, our data demonstrate that Dmp53 is a down stream target of dSir2 enzymatic activity and mediates some aspects of the life span extending effects of CR.

Bauer, Johannes H.; Morris, Siti Nur Sarah; Chang, Chengyi; Flatt*, Thomas; Wood, Jason G.; Helfand, Stephen L.

2009-01-01

259

Life spans of two species of tropical mayfly nymph (Ephemeroptera) from Magela Creek, Northern Territory  

Microsoft Academic Search

The nymphs of Cloeonjuviatile and a species of Tasmanocoenis were common in the shallows (< 1 m) of two billabongs in Magela Creek, Northern Territory. Monthly estimates of abundance and length frequency showed that growth and reproduction occurred continuously. Estimates of the ratio of annual production to mean biomass (PIB) were calculated with the size-frequency method, using different values for

R. Marchant

1982-01-01

260

Potentially Traumatic Events at Different Points in the Life Span and Mental Health: Findings From SHARE-Israel  

PubMed Central

This study addressed the association between adversity cumulated at different points in the life span and present mental health. Data of 1,130 participants aged 50+ were drawn from the Israeli component of the Survey of Health, Ageing and Retirement in Europe (SHARE). Measures included an inventory of potentially traumatic events, mental distress (depressive symptoms), and well-being (quality of life, life satisfaction). Adversity reported to have occurred early in life was positively related to mental health (i.e., to lower distress and higher well-being), whereas adversity reported to occur in late life was negatively related (i.e., to higher distress and lower well-being). Additional analyses showed that the positive association between early-life adversity and mental health was mainly restricted to adversity in which the primary harm was to another person (other-oriented adversity). In contrast, the negative association between late-life adversity and mental health was mainly restricted to adversity in which the primary harm was to the self (self-oriented adversity). This study suggests that the differential association between cumulative adversity and mental health is best captured when accounting for both time of occurrence and adversity type.

Shrira, Amit; Shmotkin, Dov; Litwin, Howard

2012-01-01

261

Mental health in adults with mild and moderate intellectual disabilities: the role of recent life events and traumatic experiences across the life span.  

PubMed

The aim of the present study is to investigate the association between recent life events and traumatic experiences across the life span and psychiatric disorders in people with ID. One hundred seventy-seven individuals with mild and moderate intellectual disability and their principal carers were assessed. Psychiatric disorders were evaluated with a semistructured psychiatric interview, the Psychiatric Assessment for Adults with Developmental Disabilities. This interview also includes a checklist of life events experienced over the previous 12 months, which was assessed through key informants. Presence of traumas was assessed through Allen's trauma history screen, also administered to key informants. After a descriptive analysis, binary logistic regression was used to see whether traumatic events and life events predicted the presence of ICD-10 disorders. A 75% of the participants had experienced at least 1 traumatic event during their life span, and 50% of the participants had experienced at least 1 life event in the 12 months previous to the study. Binary logistic regression showed that exposure to 1 or more traumatic experiences significantly increased the odds of a mental disorder (OR = 1.8), as did exposure to life events (OR = 1.4). However, when both life events and traumatic experiences were entered together in the model, calculation of odds ratios revealed that traumatic experiences significantly increased the odds of ICD-10 disorders (OR = 1.7) although life events were no longer significant. Though they have been less studied by the literature regarding predictors of mental illness in people with intellectual disability, traumatic experiences seem to play a more important role in psychopathology than life events. PMID:19282685

Martorell, Almudena; Tsakanikos, Elias; Pereda, Amada; Gutiérrez-Recacha, Pedro; Bouras, Nick; Ayuso-Mateos, José Luis

2009-03-01

262

Minocycline increases the life span and motor activity and decreases lipid peroxidation in manganese treated Drosophila melanogaster.  

PubMed

The objective of this study was to investigate the effect of Minocycline in the life span, motor activity, and lipid peroxidation of Drosophila melanogaster treated with manganese. Two days after emerging from the pupa male wild-type D. melanogaster were fed for 13 days with corn media containing 15 mM manganese. Then, they were divided in six groups of 300 flies each: group (a) remained treated with manganese (Mn group); group (b) began treatment with Minocycline (0.05 mM) (Mn-Minocycline group); group (c) received no additional treatment (Mn-no treatment group); group (d) simultaneously fed with manganese and Minocycline (Mn+Minocycline group). Additionally, a control (group e) with no treatment and another group (f) fed only with Minocycline after emerging from the pupa were added. All the manganese treated flies (group a) were dead on the 25th day. The life span in group f (101.66±1.33 days, mean S.E.M.) and of group b (97.00±3.46 days) were similar, but in both cases it was significantly higher than in group e (68.33±1.76 days), group c (67.05±2.30 days) and in those of group d (37.33±0.88). Manganese (groups a and d) decreased motor activity in D. melanogaster. In the Minocycline fed flies (groups b and f) a higher motor activity was detected. In Mn-Minocycline and Mn+Minocycline treated flies a significant decrease of MDA levels was detected when compared to the Minocycline group indicating that Minocycline and Mn appear to have a synergistic effect. In conclusion, Minocycline increased the life span and motor activity and decreased MDA formation of manganese treated D. melanogaster, probably by an inhibition of the production of reactive oxygen species. Manganese also exerted an antioxidant effect as shown by the significant decrease of MDA levels when compared to control flies. PMID:22330257

Bonilla, E; Contreras, R; Medina-Leendertz, S; Mora, M; Villalobos, V; Bravo, Y

2012-02-06

263

Aspirin and low-dose nitric oxide-donating aspirin increase life span in a Lynch syndrome mouse model.  

PubMed

Nonsteroidal anti-inflammatory drugs (NSAID) appear to be effective cancer chemopreventives. Previous cellular studies showed that aspirin (acetylsalicylic acid: ASA) and nitric oxide-donating ASA (NO-ASA) suppressed microsatellite instability (MSI) in mismatch repair (MMR)-deficient cells linked to the common cancer predisposition syndrome hereditary nonpolyposis colorectal cancer or Lynch syndrome (LS/HNPCC), at doses 300- to 3,000-fold less than ASA. Using a mouse model that develops MMR-deficient intestinal tumors that appear pathologically identical to LS/HNPCC, we show that ASA (400 mg/kg) and low-dose NO-ASA (72 mg/kg) increased life span by 18% to 21%. We also note a trend where ASA treatment resulted in intestinal tumors with reduced high MSI (H-MSI) and increased low MSI (L-MSI) as defined by the Bethesda Criteria. Low-dose NO-ASA had a minimal effect on MSI status. In contrast to previous studies, high-dose NO-ASA (720/1,500 mg/kg) treatments increased tumor burden, decreased life span, and exacerbated MSI uniquely in the LS/HNPCC mouse model. These results suggest that MMR-deficient tissues/mice may be specifically sensitive to intrinsic pharmacokinetic features of this drug. It is likely that long-term treatment with ASA may represent a chemopreventive option for LS/HNPCC patients. Moreover, as low-dose NO-ASA shows equivalent life span increase at 10-fold lower doses than ASA, it may have the potential to significantly reduce the gastropathy associated with long-term ASA treatment. PMID:21436383

McIlhatton, Michael A; Tyler, Jessica; Kerepesi, Laura A; Bocker-Edmonston, Tina; Kucherlapati, Melanie H; Edelmann, Winfried; Kucherlapati, Raju; Kopelovich, Levy; Fishel, Richard

2011-03-24

264

Genetic manipulation of longevity-related genes as a tool to regulate yeast life span and metabolite production during winemaking  

PubMed Central

Background Yeast viability and vitality are essential for different industrial processes where the yeast Saccharomyces cerevisiae is used as a biotechnological tool. Therefore, the decline of yeast biological functions during aging may compromise their successful biotechnological use. Life span is controlled by a variety of molecular mechanisms, many of which are connected to stress tolerance and genomic stability, although the metabolic status of a cell has proven a main factor affecting its longevity. Acetic acid and ethanol accumulation shorten chronological life span (CLS), while glycerol extends it. Results Different age-related gene classes have been modified by deletion or overexpression to test their role in longevity and metabolism. Overexpression of histone deacetylase SIR2 extends CLS and reduces acetate production, while overexpression of SIR2 homolog HST3 shortens CLS, increases the ethanol level, and reduces acetic acid production. HST3 overexpression also enhances ethanol tolerance. Increasing tolerance to oxidative stress by superoxide dismutase SOD2 overexpression has only a moderate positive effect on CLS. CLS during grape juice fermentation has also been studied for mutants on several mRNA binding proteins that are regulators of gene expression at the posttranscriptional level; we found that NGR1 and UTH4 deletions decrease CLS, while PUF3 and PUB1 deletions increase it. Besides, the pub1? mutation increases glycerol production and blocks stress granule formation during grape juice fermentation. Surprisingly, factors relating to apoptosis, such as caspase Yca1 or apoptosis-inducing factor Aif1, play a positive role in yeast longevity during winemaking as their deletions shorten CLS. Conclusions Manipulation of regulators of gene expression at both transcriptional (i.e., sirtuins) and posttranscriptional (i.e., mRNA binding protein Pub1) levels allows to modulate yeast life span during its biotechnological use. Due to links between aging and metabolism, it also influences the production profile of metabolites of industrial relevance.

2013-01-01

265

Alteration of Drosophila life span using conditional, tissue-specific expression of transgenes triggered by doxycyline or RU486/Mifepristone.  

PubMed

The conditional systems Tet-on and Geneswitch were compared and optimized for the tissue-specific expression of transgenes and manipulation of life span in adult Drosophila. Two versions of Tet-on system reverse-tetracycline-Trans-Activator (rtTA) were compared: the original rtTA, and rtTAM2-alt containing mutations designed to optimize regulation and expression. The rtTAM2-alt version gave less leaky expression of target constructs in the absence of doxycyline, however the absolute level of expression that could be achieved was less than that produced by rtTA, in contrast to a previous report. Existing UAS-rtTAM2-alt insertions were re-balanced, and combined with several tissue-general and tissue-specific GAL4 driver lines to yield tissue-specific, doxycyline-inducible transgene expression over three orders of magnitude. The Geneswitch (GS) system also had low background, but the absolute level of expression was low relative to Tet-on. Consequently, actin5C-GS multi-insert chromosomes were generated and higher-level expression was achieved without increased background. Moderate level over-expression of MnSOD has beneficial effects on life span. Here high-level over-expression of MnSOD was found to have toxic effects. In contrast, motor-neuron-specific over-expression of MnSOD had no detectable effect on life span. The results suggest that motor-neuron tissue is not the essential tissue for either MnSOD induced longevity or toxicity in adult males. PMID:17349761

Ford, Daniel; Hoe, Nicholas; Landis, Gary N; Tozer, Kevin; Luu, Allan; Bhole, Deepak; Badrinath, Ananth; Tower, John

2007-01-26

266

The paradox of the short life span of organisms with long telomeres: A possible solution to this paradox  

SciTech Connect

Earlier we proposed an idea about the direct proportional dependence between the length of buffer DNA at the ends of chromosomes, i.e., telomeric DNA, and the life span of organisms. In these publications, we predicted the phenomenon of shortening of telomeric DNA as a result of under-replication (incomplete replication) of terminal DNA sequences. In this study, we try to demonstrate that this shortening of telomeric DNA may indeed be a leading factor in the process of fibroblast aging. 12 refs.

Olovnikov, A.M. [Semenov Institute of Chemical Physics, Moscow (Russian Federation)

1995-07-01

267

Characterization of survival and phenotype throughout the life span in UCP2\\/UCP3 genetically altered mice  

Microsoft Academic Search

In the present investigation we describe the life span characteristics and phenotypic traits of ad libitum-fed mice that overexpress UCP2\\/3 (Positive-TG), their non-overexpressing littermates (Negative-TG), mice that do not expression UCP2 (UCP2KO) or UCP3 (UCP3KO), and wild-type C57BL\\/6J mice (WT-Control). We also included a group of C57BL\\/6J mice calorie-restricted to 70% of ad libitum-fed mice in order to test partially

Roger B. McDonald; Keya M. Walker; David B. Warman; Stephen M. Griffey; Craig H. Warden; Jon J. Ramsey; Barbara A. Horwitz

2008-01-01

268

Hormonal characteristics of the human menstrual cycle throughout reproductive life.  

PubMed Central

The changes in serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FHS), estradiol, and progesterone that occur both early and late in reproductive life were characterized and compared with findings in young, normal women and in patients with certain menstrual disorders. A total of 50 complete menstrual cycles in 37 were examined. Five distinct patterns of hormonal regulation were found, three of which are reported here: (a) A long follicular phase and delayed follicular maturation in young women with long, unpredictable intermenstrual intervals from menarche; (b) a short follicular phase with increasing age and in short cycles in perimenopausal women; and (c) true anovulatory vaginal bleeding in long cycles in perimenopausal women. The short cycles before and during the menopausal transition were found to have lower E2 levels and high FSH concentrations throughout, while LH remained in the normal range. During long cycles in perimenopausal women, concentrations of LH and FSH were in the menopausal range. However, follicular maturation was observed months after high levels of gonadotropins were attained. These studies permit the characterization of the menstrual history of the normal woman in terms of the hormonal changes that occur and provide a basis for the definition of several disorders of follicular maturation. Images

Sherman, B M; Korenman, S G

1975-01-01

269

Variables associated with circuit life span in critically ill patients undergoing continuous renal replacement therapy: a prospective observational study.  

PubMed

One of the greatest problems in performing continuous renal replacement therapy (CRRT) is premature coagulation of the circuit. The aim of the current study was to monitor the circuit function prospectively and analyze patient-related variables that may affect circuit life. Critically ill patients admitted to the intensive care unit of a tertiary hospital between August 2010 and August 2011 receiving continuous veno-venous hemofiltration (CVVH) with systemic heparin anticoagulation were prospectively studied. Variables including body temperature, blood pH value, ionized calcium level, activated partial thromboplastin time (aPTT), prothrombin time (PT), platelet count, and heparin dose were collected and analyzed for their association with circuit life span. Fifty-four patients treated by CVVH were included, with 255 filters. The filter life was 29.7 ± 13.4 hours (mean ± standard deviation [SD]). Circuits with longer survival time appeared to have lower body temperature (37.80 ± 1.14 vs. 36.36 ± 1.09; p< 0.05), lower levels of serum ionized calcium (0.80 vs. 1.29; p< 0.05), and to be more acidic (7.233 vs. 7.377; p< 0.05). Cox regression showed that pH value and ionized calcium levels were significantly associated with circuit life. Other variables of hematocrit, albumin levels, platelet count, aPTT, PT, or dose of heparin were not significantly associated with circuit life. PMID:22210650

Zhang, Zhongheng; Ni, Hongying; Lu, Baolong

270

Telomerase-mediated life-span extension of human primary fibroblasts by human artificial chromosome (HAC) vector  

SciTech Connect

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 days 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.

Shitara, Shingo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Kakeda, Minoru; Nagata, Keiko [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Hiratsuka, Masaharu [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Sano, Akiko; Osawa, Kanako; Okazaki, Akiyo [Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan); Katoh, Motonobu; Kazuki, Yasuhiro; Oshimura, Mitsuo [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Tomizuka, Kazuma [Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, 86 Nishimachi, Yonago, Tottori 683-8503 (Japan); Discovery Research Laboratories, Kirin Pharma Co., Ltd., 3 Miyahara-cho, Takasaki-shi, Gunma 370-1295 (Japan)], E-mail: ktomizuka@kirin.co.jp

2008-05-09

271

Lifelong susceptibility to acoustic trauma: changing patterns of cochlear damage over the life span of the mouse.  

PubMed

Age-related differences in susceptibility to noise-induced threshold shift (NITS) were examined over the entire life span of the CBA/J mouse. Mice of varying ages were given a single 5-min exposure to a 124-dB octave-band (12-24 kHz) noise. Susceptibility began at 15-16 days postpartum and increased rapidly until approximately 20 days of age. During this phase, NITS (as measured by increased action potential threshold) was greatest at 16 kHz. Overall susceptibility was consistently high from 20 to 90 days. During this phase, NITS became most severe at 32 kHz. From 120 days until beyond the end of its actuarial life span (527 days), NITS no longer occurred at 2-16 kHz, but the 64-kHz response retained its susceptibility to acoustic trauma. Mice at 20 and 60 days of age showed the same pattern of decreasing susceptibility as the intensity of the noise exposure was reduced to 114 and 104 dB, indicating that the absence of a tightly restricted critical period is not peculiar to a particular sound pressure level. PMID:6615342

Henry, K R

1983-01-01

272

Reproductive life history variation among colour morphs of the pygmy grasshopper Tetrix subulata  

Microsoft Academic Search

Individuals of pygmy grasshoppers (Tetrix subulata[L.] Orthoptera: Tetrigidae) exhibit genetically coded discontinuous variation in colour pattern. To determine whether reproductive performance is likely to be affected by colour pattern, this study investigated variation in body size and reproductive life-history characteristics among individuals belonging to five different colour morphs. The proportion of reproductive females (i.e. females with eggs) declined significantly as

ANDERS FORSMAN

1999-01-01

273

Review of the literature and suggestions for the design of rodent survival studies for the identification of compounds that increase health and life span.  

PubMed

Much of the literature describing the search for agents that increase the life span of rodents was found to suffer from confounds. One-hundred-six studies, absent 20 contradictory melatonin studies, of compounds or combinations of compounds were reviewed. Only six studies reported both life span extension and food consumption data, thereby excluding the potential effects of caloric restriction. Six other studies reported life span extension without a change in body weight. However, weight can be an unreliable surrogate measure of caloric consumption. Twenty studies reported that food consumption or weight was unchanged, but it was unclear whether these data were anecdotal or systematic. Twenty-nine reported extended life span likely due to induced caloric restriction. Thirty-six studies reported no effect on life span, and three a decrease. The remaining studies suffer from more serious confounds. Though still widely cited, studies showing life span extension using short-lived or "enfeebled" rodents have not been shown to predict longevity effects in long-lived animals. We suggest improvements in experimental design that will enhance the reliability of the rodent life span literature. First, animals should receive measured quantities of food and its consumption monitored, preferably daily, and reported. Weights should be measured regularly and reported. Second, a genetically heterogeneous, long-lived rodent should be utilized. Third, chemically defined diets should be used. Fourth, a positive control (e.g., a calorically restricted group) is highly desirable. Fifth, drug dosages should be chosen based on surrogate endpoints or accepted cross-species scaling factors. These procedures should improve the reliability of the scientific literature and accelerate the identification of longevity and health span-enhancing agents. PMID:21424790

Spindler, Stephen Richard

2011-03-22

274

Problem-Based Learning Spanning Real and Virtual Words: A Case Study in Second Life  

ERIC Educational Resources Information Center

There is a growing use of immersive virtual environments for educational purposes. However, much of this activity is not yet documented in the public domain, or is descriptive rather than analytical. This paper presents a case study in which university students were tasked with building an interactive learning experience using Second Life as a…

Good, Judith; Howland, Katherine; Thackray, Liz

2008-01-01

275

Ethical Concerns in the Community About Technologies to Extend Human Life Span  

Microsoft Academic Search

Debates about the ethical and social implications of research that aims to extend human longevity by intervening in the ageing process have paid little attention to the attitudes of members of the general public. In the absence of empirical evidence, conflicting assumptions have been made about likely public attitudes towards life-extension. In light of recent calls for greater public involvement

Brad Partridge; Mair Underwood; Jayne Lucke; Helen Bartlett; Wayne Hall

2009-01-01

276

Life Span as the Measure of Performance and Learning in a Business Gaming Simulation  

ERIC Educational Resources Information Center

|This study applies the learning curve method of measuring learning to participants of a computer-assisted business gaming simulation that includes a multiple-life-cycle feature. The study involved 249 participants. It verified the workability of the feature and estimated the participants' rate of learning at 17.4% for every doubling of…

Thavikulwat, Precha

2012-01-01

277

Problem-Based Learning Spanning Real and Virtual Words: A Case Study in Second Life  

ERIC Educational Resources Information Center

|There is a growing use of immersive virtual environments for educational purposes. However, much of this activity is not yet documented in the public domain, or is descriptive rather than analytical. This paper presents a case study in which university students were tasked with building an interactive learning experience using Second Life as a…

Good, Judith; Howland, Katherine; Thackray, Liz

2008-01-01

278

Plant Reproduction. Plant Life in Action[TM]. Schlessinger Science Library. [Videotape].  

ERIC Educational Resources Information Center

|Plants are vital to all other life on this planet - without them, there would be no food, shelter or oxygen. Luckily, over millions of years plants have developed many different features in order to survive and reproduce. In Plant Reproduction, students will discover that primitive mosses and algae are dependent upon water for their reproduction.…

2000

279

COPEPOD REPRODUCTIVE STRATEGIES: LIFE-HISTORY THEORY, PHYLOGENETIC PATTERN AND INVASION OF INLAND WATERS. (R824771)  

EPA Science Inventory

Abstract Life-history theory predicts that different reproductive strategies should evolve in environments that differ in resource availability, mortality, seasonality, and in spatial or temporal variation. Within a population, the predicted optimal strategy is driven ...

280

Can we increase our life span? The role of nuclear gerontology.  

PubMed

Elderly people, those above 60 or 65 years old differ from younger people in many ways. Nuclear medicine can play a role in the diagnosis of diseases of the elderly and thus help, in social adjustment and in care for the elderly people. The question is why adult stem cells have a certain limit of reproduction, since their DNA in a normal physical environment can theoretically live very much longer. The elderly are prone to suffer more diseases than the young. It is important that the elderly should use water soluble and not lipid soluble drugs. There are many more to write about the elderly. We have tried to be brief in order to show the importance of using nuclear medicine in gerontology. Let us mention here that the word gerontology means in greek "talk about the elderly" (gerontas is the old man and logy is to talk about). Elderly people are a large part of our society and we do have every reason, every interest and responsibility to keep this part of our society healthy, useful and productive. PMID:21193870

Grammaticos, Philip

281

The serotonin transporter gene and functional and pathological adaptation to environmental variation across the life span.  

PubMed

In analogy with the accepted view that behaviour is shaped by gene×environment (G×E) interactions, G×E studies are exponentially increasing in the field of psychiatry. Whereas research was primarily driven by the premature view that negative environmental stimuli can trigger psychopathology in those subjects that are genetically predisposed, a closer look at the available data shows that G×E interactions are much more complex than initially thought. Here, we discuss G×E studies focussing on serotonin transporter (5-HTT, SERT, SLC6A4) gene variation in humans, monkeys, and rodents. Recent studies, across species, confirm the theorized 'for-better-and-for-worse' effect of low activity serotonin transporter genotypes. In addition, while 5-HTT×E interactions were thought to take place in early life, recent evidence illustrates that these interactions are also manifested in adulthood. Therefore, we discuss data based on 5-HTT×E interactions, and propose a model in which predictive adaptive responses (PARs), as shaped by early life 5-HTT×E interactions, shape responses to environmental challenges in later life, i.e. reflecting 5-HTT×E×E interactions. PMID:22954594

Homberg, Judith R; van den Hove, Daniel L A

2012-08-28

282

Visualizing Life Zone Boundary Sensitivities Across Climate Models and Temporal Spans  

SciTech Connect

Life zones are a convenient and quantifiable method for delineating areas with similar plant and animal communities based on bioclimatic conditions. Such ecoregionalization techniques have proved useful for defining habitats and for studying how these habitats may shift due to environmental change. The ecological impacts of climate change are of particular interest. Here we show that visualizations of the geographic projection of life zones may be applied to the investigation of potential ecological impacts of climate change using the results of global climate model simulations. Using a multi-factor classification scheme, we show how life zones change over time based on quantitative model results into the next century. Using two straightforward metrics, we identify regions of high sensitivity to climate changes from two global climate simulations under two different greenhouse gas emissions scenarios. Finally, we identify how preferred human habitats may shift under these scenarios. We apply visualization methods developed for the purpose of displaying multivariate relationships within data, especially for situations that involve a large number of concurrent relationships. Our method is based on the concept of multivariate classification, and is implemented directly in VisIt, a production quality visualization package.

Sisneros, Roberto R [ORNL; Huang, Jian [University of Tennessee, Knoxville (UTK); Ostrouchov, George [ORNL; Hoffman, Forrest M [ORNL

2011-01-01

283

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

284

Cell specific radiation dosimetry in skeleton from life-span carcinogenesis studies. Final report  

SciTech Connect

The osteogenic sarcoma is the dominant life-threatening pathology in lifespan studies of beagles exposed to alpha-emitting bone-seeking radionuclides. It was deduced from these studies that certain skeletal sites are more prone to develop tumors. This project sought to determine the bone cells at risk and their cell-specific radiation dose. The cell-specific radiation dose values are related to loss and high Ra-226 and Pu-239 induced osteogenic sarcoma sites, to test different dose response hypothesis and predict the extent of effects in humans.

Webster, S.S.J.

1993-04-05

285

Overexpression of HGF retards disease progression and prolongs life span in a transgenic mouse model of ALS.  

PubMed

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a progressive loss of motoneurons and degeneration of motor axons. We show that overexpression of hepatocyte growth factor (HGF) in the nervous system attenuates motoneuron death and axonal degeneration and prolongs the life span of transgenic mice overexpressing mutated Cu2+/Zn2+ superoxide dismutase 1. HGF prevented induction of caspase-1 and inducible nitric oxide synthase (iNOS) in motoneurons and retained the levels of the glial-specific glutamate transporter (excitatory amino acid transporter 2/glutamate transporter 1) in reactive astrocytes. We propose that HGF may be the first example of an endogenous growth factor that can alleviate the symptoms of ALS by direct neurotrophic activities on motoneurons and indirect activities on glial cells, presumably favoring a reduction in glutamatergic neurotoxicity. PMID:12151533

Sun, Woong; Funakoshi, Hiroshi; Nakamura, Toshikazu

2002-08-01

286

Global existence, large time behavior, and life span for a degenerate parabolic equation with inhomogeneous density and source  

NASA Astrophysics Data System (ADS)

This paper deals with the Cauchy problem for a degenerate parabolic equation with inhomogeneous density and source |x|^{l1}u_t = div(u^{m - 1}|nabla u|^{? - 1}nabla u) + |x|^{l2}uq, quad(x, t) in {R}^N × (0, infty), where {N ? 1, m + ? - 2 > 0, q > m + ? - 1}, and {0 ? l1 ? l2 < q - (m + ? - 1)/m + ? - 2N}. Firstly, we establish the secondary critical exponent on the decay asymptotic behavior of an initial value at infinity for the existence and non existence of global solutions of the Cauchy problem. Moreover, we give the large time behavior of the global solution. Finally, the precise estimate of life span for the solution is obtained.

Zheng, Pan; Mu, Chunlai

2013-05-01

287

Graphic integration of causal factors of pelvic floor disorders: an integrated life span model.  

PubMed

There is growing interest in causal factors for pelvic floor disorders. These conditions include pelvic organ prolapse and urinary and fecal incontinence and are affected by a myriad of factors that increase occurrence of symptomatic disease. Unraveling the complex causal network of genetic factors, birth-induced injury, connective tissue aging, lifestyle and comorbid factors is challenging. We describe a graphical tool to integrate the factors affecting pelvic floor disorders. It plots pelvic floor function in 3 major life phases: (1) development of functional reserve during an individual's growth, (2) variations in the amount of injury and potential recovery that occur during and after vaginal birth, and (3) deterioration that occurs with advancing age. This graphical tool accounts for changes in different phases to be integrated to form a disease model to help assess the overlap of different causal factors. PMID:18533115

Delancey, John O L; Kane Low, Lisa; Miller, Janis M; Patel, Divya A; Tumbarello, Julie A

2008-06-04

288

Sickle Cell Disease: An Opportunity for Palliative Care across the Life Span  

PubMed Central

Sickle cell disease is a chronic illness that impacts patients physically and emotionally and can do so at an early age. An ecological model of palliative care that involves improved communication among the health care team, patients, and their families can be beneficial. Open and honest communication regarding advance care planning, disease management, relief of pain and other symptoms, and bereavement and grief are all important for the patient, family, and health care team. Given the multiple acute and chronic complications of sickle cell disease, an approach to care that is holistic and comprehensive may help to improve a patient’s biological function and the perceived health, functional status, and quality of life of the patient and family.

Johnson, Bonnye; Mack, A. Kyle; Labotka, Richard; Molokie, Robert E.

2010-01-01

289

Statistical modeling of biomedical corpora: mining the Caenorhabditis Genetic Center Bibliography for genes related to life span  

PubMed Central

Background The statistical modeling of biomedical corpora could yield integrated, coarse-to-fine views of biological phenomena that complement discoveries made from analysis of molecular sequence and profiling data. Here, the potential of such modeling is demonstrated by examining the 5,225 free-text items in the Caenorhabditis Genetic Center (CGC) Bibliography using techniques from statistical information retrieval. Items in the CGC biomedical text corpus were modeled using the Latent Dirichlet Allocation (LDA) model. LDA is a hierarchical Bayesian model which represents a document as a random mixture over latent topics; each topic is characterized by a distribution over words. Results An LDA model estimated from CGC items had better predictive performance than two standard models (unigram and mixture of unigrams) trained using the same data. To illustrate the practical utility of LDA models of biomedical corpora, a trained CGC LDA model was used for a retrospective study of nematode genes known to be associated with life span modification. Corpus-, document-, and word-level LDA parameters were combined with terms from the Gene Ontology to enhance the explanatory value of the CGC LDA model, and to suggest additional candidates for age-related genes. A novel, pairwise document similarity measure based on the posterior distribution on the topic simplex was formulated and used to search the CGC database for "homologs" of a "query" document discussing the life span-modifying clk-2 gene. Inspection of these document homologs enabled and facilitated the production of hypotheses about the function and role of clk-2. Conclusion Like other graphical models for genetic, genomic and other types of biological data, LDA provides a method for extracting unanticipated insights and generating predictions amenable to subsequent experimental validation.

2006-01-01

290

Aging in the cerebellum and hippocampus and associated behaviors over the adult life span of CB6F1 mice.  

PubMed

In the present study we examined the effects of normal aging in the hippocampus and cerebellum, as well as behaviors associated with these substrates. A total of 67 CB6F1 hybrid mice were tested at one of five ages (4, 8, 12, 18 or 25 months) on the context pre-exposure facilitation effect (CPFE) modification of fear conditioning, rotorod, Barnes maze, acoustic startle, Morris water maze (MWM) and 500-ms trace eyeblink classical conditioning (EBCC). Behavioral tasks were chosen to increase the ability to detect age-related changes in learning, as trace EBCC is considered a more difficult paradigm (compared to delay EBCC) and the CPFE has been found to be more sensitive to hippocampus insults than standard contextual fear conditioning. To assess the effects of age on the brain, hippocampus volume was calculated and unbiased stereology was used to estimate the number of Purkinje neurons in the cerebellar cortex. A significant, age-related loss of Purkinje neurons was found-beginning at 12 months of age-and hippocampus volume remained stable over the adult life span. Age-related impairment was found, beginning at 12-18 months in the rotorod, and mice with fewer Purkinje neurons showed greater impairment in this task. CB6F1 mice retained auditory acuity across the life span and mice aged 25 months showed significant age-related impairment in the EBCC task; however, deficits were not associated with the loss of Purkinje neurons. Although the CPFE task is considered more sensitive to hippocampus insult, no age-related impairment was found. Spatial memory retention was impaired in the Barnes maze at 25 months, but no significant deficits were seen in the MWM. These results support the finding of differential aging in the hippocampus and cerebellum. PMID:23764510

Kennard, J A; Brown, K L; Woodruff-Pak, D S

2013-06-11

291

Grade Span.  

ERIC Educational Resources Information Center

|This issue reviews grade span, or grade configuration. Catherine Paglin and Jennifer Fager's "Grade Configuration: Who Goes Where?" provides an overview of issues and concerns related to grade spans and supplies profiles of eight Northwest schools with varying grade spans. David F. Wihry, Theodore Coladarci, and Curtis Meadow's "Grade Span and…

Renchler, Ron

2000-01-01

292

Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice  

PubMed Central

Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while at the same time live shorter lives. These relationships have been combined in the ‘membrane pacemaker hypothesis of aging’. It suggests that membrane PUFA content might determine an animal’s life span. PUFAs in general and certain long-chain PUFAs in particular, are highly prone to lipid peroxidation which brings about a high rate of reactive oxygen species (ROS) production. We hypothesized that dietary supplementation of either n-3 or n-6 PUFAs might affect (1) membrane phospholipid composition of heart and liver tissues and (2) life span of the animals due to the altered membrane composition, and subsequent effects on lipid peroxidation. Therefore, we kept female laboratory mice from the C57BL/6 strain on three diets (n-3 PUFA rich, n-6 PUFA rich, control) and assessed body weights, life span, heart, and liver phospholipid composition after the animals had died. We found that while membrane phospholipid composition clearly differed between feeding groups, life span was not directly affected. However, we were able to observe a positive correlation between monounsaturated fatty acids in cardiac muscle and life span.

Ruf, Thomas

2010-01-01

293

The Effect of ACP?-ADA? Genetic Interaction on Human Life Span.  

PubMed

Acid phosphatase (ACP?) is a polymorphic enzyme that catalyzes the conversion of flavin-mononucleotide (FMN) to riboflavin and regulates the cellular concentration of flavin-adenine-dinucleotide (FAD) and, consequently, energy metabolism. Its activity is modulated by adenosine deaminase locus 1 (ADA?) genotype. The aim of our work is to verify whether individuals with a high proportion of ACP? f-isozyme and carrying the ADA?*2 allele, displaying the highest phosphatase activity, may have a higher life expectancy. Genomic DNA was extracted from the peripheral blood of 569 females and 509 males (18 to 106 years of age) randomly recruited from Central Italy. These samples were subdivided into three sex-specific age groups (the ages of women are in square bracket): Class 1: age <66 [<73]; Class 2: ages 66 to 88 [73 to 91]; Class 3: age >88 [>91]. ACP?and ADA? singlenucleotide polymorphisms (SNPs) were genotyped by restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) methods and statistical analyses were performed with SPSS 14.0. The results showed a larger proportion of Class 3 individuals displaying high ACP? f-isozyme concentration and carrying the ADA?*2 allele than those individuals of Class 2 and Class 2 plus Class 1. Thus, we postulate that in Class 3 individuals the high phosphatase activity, resulting from the combined presence of high ACP? f-isozyme concentration and the ADA?*2 allele, lowers the rate of glycolysis that may reduce the amount of metabolic calories and, in turn, activate Sirtuin genes that protect cells against age-related diseases. PMID:23959645

Lucarini, Nazzareno; Napolioni, Valerio; Magrini, Andrea; Gloria, Fulvia

2012-12-01

294

Long-term aerobic exercise is associated with greater muscle strength throughout the life span.  

PubMed

Aging is associated with a progressive decline in muscle strength, muscle mass, and aerobic capacity, which reduces mobility and impairs quality of life in elderly adults. Exercise is commonly employed to improve muscle function in individuals of all ages; however, chronic aerobic exercise is believed to largely impact cardiovascular function and oxidative metabolism, with minimal effects on muscle mass and strength. To study the effects of long-term aerobic exercise on muscle strength, we recruited 74 sedentary (SED) or highly aerobically active (ACT) men and women from within three distinct age groups (young: 20-39 years, middle: 40-64 years, and older: 65-86 years) and tested their aerobic capacity, isometric grip and knee extensor strength, and dynamic 1 repetition maximum knee extension. As expected, ACT subjects had greater maximal oxygen uptake and peak aerobic power output compared with SED subjects (p < .05). Grip strength relative to body weight declined with age (p < .05) and was greater in ACT compared with SED subjects in both hands (p < .05). Similarly, relative maximal isometric knee extension torque declined with age (p < .05) and was higher in ACT versus SED individuals in both legs (p < .05). Absolute and relative 1 repetition maximum knee extension declined with age (p < .05) and were greater in ACT versus SED groups (p < .05). Knee extensor strength was associated with a greater amount of leg lean mass in the ACT subjects (p < .05). In summary, long-term aerobic exercise appears to attenuate age-related reductions in muscle strength in addition to its cardiorespiratory and metabolic benefits. PMID:23213030

Crane, Justin D; Macneil, Lauren G; Tarnopolsky, Mark A

2012-12-03

295

Early Life Exposure to Genistein and Daidzein Disrupts Structural Development of Reproductive Organs in Female Mice  

Microsoft Academic Search

In mice, exposure to isoflavones (ISO), abundant in soy infant formula, during the first 5 d of life alters structural and functional development of reproductive organs. Effects of longer exposures are unknown. The study objective was to evaluate whether exposure to a combination of daidzein and genistein in the first 10 compared to 5 d of life results in greater

Jovana Kaludjerovic; Jianmin Chen; Wendy E. Ward

2012-01-01

296

Reproductive decisions are sensitive to cues of life expectancy: the case of a moth  

Microsoft Academic Search

Life history theory predicts that reproductive effort should increase as life expectancy decreases. Empirical evidence in support of this hypothesis is still fragmentary. We measured the effects of different potential indexes of mortality risk on oviposition in a geometrid moth Scotopteryx chenopodiata L. We conducted two experiments: in one we manipulated mortality risk by clipping wings or depriving the moths

Juhan Javoiš; Toomas Tammaru

2004-01-01

297

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

PubMed Central

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.

Arnaud-Haond, Sophie; Duarte, Carlos M.; Diaz-Almela, Elena; Marba, Nuria; Sintes, Tomas; Serrao, Ester A.

2012-01-01

298

Environmental enrichment improves age-related immune system impairment: long-term exposure since adulthood increases life span in mice.  

PubMed

Age-related changes in immunity have been shown to highly influence morbidity and mortality. The aim of the present work was to study the effects of environmental enrichment (EE) (8-16 weeks) on several functions and oxidative stress parameters of peritoneal leukocytes, previously described as health and longevity markers, in mice at different ages, namely adult (44 +/- 4 weeks), old (69 +/- 4 weeks), and very old (92 +/- 4 weeks). Mortality rates were monitored in control and enriched animals, and effects on survival of long-term exposure to EE until natural death were determined. The results showed that exposure to EE was efficient in improving the function (i.e., macrophage chemotaxis and phagocytosis, lymphocyte chemotaxis and proliferation, natural killer cell activity, interleukin-2 and tumor necrosis factor-alpha levels) and decreasing the oxidative-inflammatory stress (i.e., lowered oxidized glutathione content, xanthine oxidase activity, expression of Toll-like receptors 2 and 4 on CD4 and CD8 cells, and increased reduced glutathione and glutathione peroxidase and catalase activities) of immune cells. These positive effects of EE were especially remarkable in animals at older ages. Importantly, long-term exposure to EE from adult age and until natural death stands out as a useful strategy to extend longevity. Thus, the present work confirms the importance of maintaining active mental and/or physical activity aiming to improve quality of life in terms of immunity, and demonstrates that this active life must be initiated at early stages of the aging process and preserved until death to improve life span. PMID:20707722

Arranz, Lorena; De Castro, Nuria M; Baeza, Isabel; Maté, Ianire; Viveros, Maria Paz; De la Fuente, Mónica

2010-08-01

299

Deterioration, death and the evolution of reproductive restraint in late life.  

PubMed

Explaining why organisms schedule reproduction over their lifetimes in the various ways that they do is an enduring challenge in biology. An influential theoretical prediction states that organisms should increasingly invest in reproduction as they approach the end of their life. An apparent mismatch of empirical data with this prediction has been attributed to age-related constraints on the ability to reproduce. Here we present a general framework for the evolution of age-related reproductive trajectories. Instead of characterizing an organism by its age, we characterize it by its physiological condition. We develop a common currency that if maximized at each time guarantees the whole life history is optimal. This currency integrates reproduction, mortality and changes in condition. We predict that under broad conditions it will be optimal for organisms to invest less in reproduction as they age, thus challenging traditional interpretations of age-related traits and renewing debate about the extent to which observed life histories are shaped by constraint versus adaptation. Our analysis gives a striking illustration of the differences between an age-based and a condition-based approach to life-history theory. It also provides a unified account of not only standard life-history models but of related models involving the allocation of limited resources. PMID:19726476

McNamara, John M; Houston, Alasdair I; Barta, Zoltan; Scheuerlein, Alexander; Fromhage, Lutz

2009-09-02

300

Deterioration, death and the evolution of reproductive restraint in late life  

PubMed Central

Explaining why organisms schedule reproduction over their lifetimes in the various ways that they do is an enduring challenge in biology. An influential theoretical prediction states that organisms should increasingly invest in reproduction as they approach the end of their life. An apparent mismatch of empirical data with this prediction has been attributed to age-related constraints on the ability to reproduce. Here we present a general framework for the evolution of age-related reproductive trajectories. Instead of characterizing an organism by its age, we characterize it by its physiological condition. We develop a common currency that if maximized at each time guarantees the whole life history is optimal. This currency integrates reproduction, mortality and changes in condition. We predict that under broad conditions it will be optimal for organisms to invest less in reproduction as they age, thus challenging traditional interpretations of age-related traits and renewing debate about the extent to which observed life histories are shaped by constraint versus adaptation. Our analysis gives a striking illustration of the differences between an age-based and a condition-based approach to life-history theory. It also provides a unified account of not only standard life-history models but of related models involving the allocation of limited resources.

McNamara, John M.; Houston, Alasdair I.; Barta, Zoltan; Scheuerlein, Alexander; Fromhage, Lutz

2009-01-01

301

Reproductive isolation following reintroduction of Chinook salmon with alternative life histories  

Microsoft Academic Search

We evaluated reproductive isolation of Chinook salmon (Oncorhynchus tshawytscha) life history types that have been reintroduced to northern Idaho, USA. Analysis of 1003 samples at six microsatellite loci\\u000a revealed strong reproductive isolation between ocean- and stream-type Chinook salmon (fall and summer spawn timing, respectively)\\u000a within the Clearwater River sub-basin (F\\u000a ST = 0.148, P < 0.00001). Very little evidence for gene flow among the

Shawn R. Narum; William D. Arnsberg; Andre J. Talbot; Madison S. Powell

2007-01-01

302

Population fluctuations, reproductive costs and life-history tactics in female Soay sheep  

Microsoft Academic Search

Summary 1. Though models of life-history decisions are traditionally based on age-related changes in the costs and benefits of reproduction, in nature both costs and benefits vary with individual differences in phenotype as well as with environmental changes. 2. Using long-term records of individual reproduction and survival in the Soay sheep of St Kilda, we show that the costs and

T. H. CLUTTON-BROCK; I. R. STEVENSON; P. MARROW; A. D. MACCOLL

303

Senescence and life span  

Microsoft Academic Search

Senescence is a general cellular process that occurs as a response to stress and damage. It forms an alternative response\\u000a of cells to damage that might otherwise cause programmed cell death. Whereas telomere shortening leading to telomere dysfunction\\u000a was the first described cause of senescence, it is now known that senescence can result from many sources of damage. Senescent\\u000a cells

Peter J. Hornsby; Pflugers Arch; Eur J Physiol

2010-01-01

304

The physiology\\/life-history nexus  

Microsoft Academic Search

The rate of reproduction, age at maturity and longevity vary widely among species. Most of this life-history variation falls on a slow-fast continuum, with low reproductive rate, slow development and long life span at one end and the opposite traits at the other end. The absence of alternative combinations of these variables implies constraint on the diversification of life histories,

Robert E. Ricklefs; Martin Wikelski

2002-01-01

305

Histone H1 Is Dispensable for Methylation-Associated Gene Silencing in Ascobolus immersus and Essential for Long Life Span  

PubMed Central

A gene encoding a protein that shows sequence similarity with the histone H1 family only was cloned in Ascobolus immersus. The deduced peptide sequence presents the characteristic three-domain structure of metazoan linker histones, with a central globular region, an N-terminal tail, and a long positively charged C-terminal tail. By constructing an artificial duplication of this gene, named H1, it was possible to methylate and silence it by the MIP (methylation induced premeiotically) process. This resulted in the complete loss of the Ascobolus H1 histone. Mutant strains lacking H1 displayed normal methylation-associated gene silencing, underwent MIP, and showed the same methylation-associated chromatin modifications as did wild-type strains. However, they displayed an increased accessibility of micrococcal nuclease to chromatin, whether DNA was methylated or not, and exhibited a hypermethylation of the methylated genome compartment. These features are taken to imply that Ascobolus H1 histone is a ubiquitous component of chromatin which plays no role in methylation-associated gene silencing. Mutant strains lacking histone H1 reproduced normally through sexual crosses and displayed normal early vegetative growth. However, between 6 and 13 days after germination, they abruptly and consistently stopped growing, indicating that Ascobolus H1 histone is necessary for long life span. This constitutes the first observation of a physiologically important phenotype associated with the loss of H1.

Barra, Jose L.; Rhounim, Laila; Rossignol, Jean-Luc; Faugeron, Godeleine

2000-01-01

306

Comparative longitudinal structural analyses of the growth and decline of multiple intellectual abilities over the life span.  

PubMed

Latent growth curve techniques and longitudinal data are used to examine predictions from the theory of fluid and crystallized intelligence (Gf-Gc theory; J. L. Horn & R. B. Cattell, 1966, 1967). The data examined are from a sample (N approximately 1,200) measured on the Woodcock-Johnson Psycho-Educational Battery-Revised (WJ-R). The longitudinal structural equation models used are based on latent growth models of age using two-occasion "accelerated" data (e.g., J. J. McArdle & R. Q. Bell, 2000; J. J. McArdle & R. W. Woodcock, 1997). Nonlinear mixed-effects growth models based on a dual exponential rate yield a reasonable fit to all life span cognitive data. These results suggest that most broad cognitive functions fit a generalized curve that rises and falls. Novel multilevel models directly comparing growth curves show that broad fluid reasoning (Gf) and acculturated crystallized knowledge (Gc) have different growth patterns. In all comparisons, any model of cognitive age changes with only a single g factor yields an overly simplistic view of growth and change over age. PMID:11806695

McArdle, John J; Ferrer-Caja, Emilio; Hamagami, Fumiaki; Woodcock, Richard W

2002-01-01

307

The ALS-associated proteins FUS and TDP-43 function together to affect Drosophila locomotion and life span  

PubMed Central

The fatal adult motor neuron disease amyotrophic lateral sclerosis (ALS) shares some clinical and pathological overlap with frontotemporal dementia (FTD), an early-onset neurodegenerative disorder. The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD. It is currently unknown whether perturbation of these proteins results in disease through mechanisms that are independent of normal protein function or via the pathophysiological disruption of molecular processes in which they are both critical. Here, we report that Drosophila mutants in which the homolog of FUS is disrupted exhibit decreased adult viability, diminished locomotor speed, and reduced life span compared with controls. These phenotypes were fully rescued by wild-type human FUS, but not ALS-associated mutant FUS proteins. A mutant of the Drosophila homolog of TDP-43 had similar, but more severe, deficits. Through cross-rescue analysis, we demonstrated that FUS acted together with and downstream of TDP-43 in a common genetic pathway in neurons. Furthermore, we found that these proteins associated with each other in an RNA-dependent complex. Our results establish that FUS and TDP-43 function together in vivo and suggest that molecular pathways requiring the combined activities of both of these proteins may be disrupted in ALS and FTD.

Wang, Ji-Wu; Brent, Jonathan R.; Tomlinson, Andrew; Shneider, Neil A.; McCabe, Brian D.

2011-01-01

308

Tetrahydrocurcumin extends life span and inhibits the oxidative stress response by regulating the FOXO forkhead transcription factor  

PubMed Central

The O-type forkhead domain transcription factor (FOXO) is involved in many biological processes such as aging, the oxidative stress response, and growth regulation. FOXO activity is tightly controlled within cells. In particular, growth factor signaling pathways and the oxidative stress response can both stimulate nuclear translocation of this transcription factor. Here, we show that tetrahydrocurcumin (THC), a curcumin metabolite, regulates the oxidative stress response and aging via FOXO. In NIH3T3 cells, THC induced nuclear accumulation of FOXO4, a member of the FOXO family of transcription factors, by inhibiting phosphorylation of protein kinase B (PKB)/Akt. In Drosophila melanogaster, THC attenuated the oxidative stress response, an effect that was blocked in a foxo mutant background. THC also extended the life span of Drosophila under normal conditions, and loss of either foxo or Sir2 activity eliminated this effect. Based on these results, THC may regulate the aging process via an evolutionarily conserved signaling pathway that includes both foxo and Sir2.

Xiang, Lan; Nakamura, Yukiko; Lim, Young-Mi; Yamasaki, Yasutoyo; Kurokawa-Nose, Yumi; Maruyama, Wakako; Osawa, Toshihiko; Matsuura, Akira; Motoyama, Noboru; Tsuda, Leo

2011-01-01

309

Effects of PPP1R1B (DARPP-32) Polymorphism on Feedback-Related Brain Potentials Across the Life Span  

PubMed Central

Maximizing gains during probabilistic reinforcement learning requires the updating of choice – outcome expectations at the time when the feedback about a specific choice or action is given. Extant theories and evidence suggest that dopaminergic modulation plays a crucial role in reinforcement learning and the updating of choice – outcome expectations. Furthermore, recently a positive component of the event-related potential about 200?ms (P2) after feedback has been suggested to reflect such updating. The efficacy of dopaminergic modulation changes across the life span. However, to date investigations of age-related differences in feedback-related P2 during reinforcement learning are still scarce. The present study thus aims to investigate whether individual differences in the feedback-related P2 would be associated with polymorphic variations in a dopamine relevant gene PPP1R1B (also known as DARPP-32) and whether the genetic effect may differ between age groups. We observed larger P2 amplitudes in individuals carrying the genotype associated with higher dopamine receptor efficacy, i.e., a allele homozygotes of a single nucleotide polymorphism (rs907094) of the PPP1R1B gene. Moreover, this effect was more pronounced in children and older adults in comparison to adolescents and younger adults. Together, our findings indicate that polymorphic variations in a dopamine relevant gene are associated with individual differences in brain-evoked potentials of outcome updating and hint at the possibility that genotype effects on neurocognitive phenotypes may vary as a function of brain maturation and aging.

Hammerer, Dorothea; Biele, Gudio; Muller, Viktor; Thiele, Holger; Nurnberg, Peter; Heekeren, Hauke R.; Li, Shu-Chen

2013-01-01

310

A review of methionine dependency and the role of methionine restriction in cancer growth control and life-span extension.  

PubMed

Methionine is an essential amino acid with many key roles in mammalian metabolism such as protein synthesis, methylation of DNA and polyamine synthesis. Restriction of methionine may be an important strategy in cancer growth control particularly in cancers that exhibit dependence on methionine for survival and proliferation. Methionine dependence in cancer may be due to one or a combination of deletions, polymorphisms or alterations in expression of genes in the methionine de novo and salvage pathways. Cancer cells with these defects are unable to regenerate methionine via these pathways. Defects in the metabolism of folate may also contribute to the methionine dependence phenotype in cancer. Selective killing of methionine dependent cancer cells in co-culture with normal cells has been demonstrated using culture media deficient in methionine. Several animal studies utilizing a methionine restricted diet have reported inhibition of cancer growth and extension of a healthy life-span. In humans, vegan diets, which can be low in methionine, may prove to be a useful nutritional strategy in cancer growth control. The development of methioninase which depletes circulating levels of methionine may be another useful strategy in limiting cancer growth. The application of nutritional methionine restriction and methioninase in combination with chemotherapeutic regimens is the current focus of clinical studies. PMID:22342103

Cavuoto, Paul; Fenech, Michael F

2012-02-17

311

A Drosophila homologue of Sir2 modifies position-effect variegation but does not affect life span.  

PubMed

Control of chromosome structure is important in the regulation of gene expression, recombination, DNA repair, and chromosome stability. In a two-hybrid screen for proteins that interact with the Drosophila CREB-binding protein (dCBP), a known histone acetyltransferase and transcriptional coactivator, we identified the Drosophila homolog of a yeast chromatin regulator, Sir2. In yeast, Sir2 silences genes via an intrinsic NAD(+)-dependent histone deacetylase activity. In addition, Sir2 promotes longevity in yeast and in Caenorhabditis elegans. In this report, we characterize the Drosophila Sir2 (dSir2) gene and its product and describe the generation of dSir2 amorphic alleles. We found that dSir2 expression is developmentally regulated and that dSir2 has an intrinsic NAD(+)-dependent histone deacetylase activity. The dSir2 mutants are viable, fertile, and recessive suppressors of position-effect variegation (PEV), indicating that, as in yeast, dSir2 is not an essential function for viability and is a regulator of heterochromatin formation and/or function. However, mutations in dSir2 do not shorten life span as predicted from studies in yeast and worms. PMID:12524341

Newman, Brenda L; Lundblad, James R; Chen, Yang; Smolik, Sarah M

2002-12-01

312

A Drosophila homologue of Sir2 modifies position-effect variegation but does not affect life span.  

PubMed Central

Control of chromosome structure is important in the regulation of gene expression, recombination, DNA repair, and chromosome stability. In a two-hybrid screen for proteins that interact with the Drosophila CREB-binding protein (dCBP), a known histone acetyltransferase and transcriptional coactivator, we identified the Drosophila homolog of a yeast chromatin regulator, Sir2. In yeast, Sir2 silences genes via an intrinsic NAD(+)-dependent histone deacetylase activity. In addition, Sir2 promotes longevity in yeast and in Caenorhabditis elegans. In this report, we characterize the Drosophila Sir2 (dSir2) gene and its product and describe the generation of dSir2 amorphic alleles. We found that dSir2 expression is developmentally regulated and that dSir2 has an intrinsic NAD(+)-dependent histone deacetylase activity. The dSir2 mutants are viable, fertile, and recessive suppressors of position-effect variegation (PEV), indicating that, as in yeast, dSir2 is not an essential function for viability and is a regulator of heterochromatin formation and/or function. However, mutations in dSir2 do not shorten life span as predicted from studies in yeast and worms.

Newman, Brenda L; Lundblad, James R; Chen, Yang; Smolik, Sarah M

2002-01-01

313

Reproduction, social behavior, and aging trajectories in honeybee workers.  

PubMed

While a negative correlation between reproduction and life span is commonly observed, specialized reproductive individuals outlive their non-reproductive nestmates in all eusocial species, including the honeybee, Apis mellifera (L). The consequences of reproduction for individual life expectancy can be studied directly by comparing reproductive and non-reproductive workers. We quantified the life span consequences of reproduction in honeybee workers by removal of the queen to trigger worker reproduction. Furthermore, we observed the social behavior of large cohorts of workers under experimental and control conditions to test for associations with individual life expectancy. Worker life expectancy was moderately increased by queen removal. Queenless colonies contained a few long-lived workers, and oviposition behavior was associated with a strong reduction in mortality risk, indicating that a reproductive role confers a significant survival advantage. This finding is further substantiated by an association between brood care behavior and worker longevity that depends on the social environment. In contrast, other in-hive activities, such as fanning, trophallaxis, and allogrooming did not consistently affect worker life expectancy. The influence of foraging varied among replicates. An earlier age of transitioning from in-hive tasks to outside foraging was always associated with shorter life spans, in accordance with previous studies. In sum, our studies quantify how individual mortality is affected by particular social roles and colony environments and demonstrate interactions between the two. The exceptional, positive association between reproduction and longevity in honeybees extends to within-caste plasticity, which may be exploited for mechanistic studies. PMID:23765046

Dixon, Luke; Kuster, Ryan; Rueppell, Olav

2013-06-14

314

Evidence for a Relationship between Longevity of Mammalian Species and Life Spans of Normal Fibroblasts in vitro and Erythrocytes in vivo  

Microsoft Academic Search

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

Dan Rohme

1981-01-01

315

dSir2 in the adult fat body, but not in muscles, regulates life span in a diet-dependent manner.  

PubMed

Sir2, an evolutionarily conserved NAD(+)-dependent deacetylase, has been implicated as a key factor in mediating organismal life span. However, recent contradictory findings have brought into question the role of Sir2 and its orthologs in regulating organismal longevity. In this study, we report that Drosophila Sir2 (dSir2) in the adult fat body regulates longevity in a diet-dependent manner. We used inducible Gal4 drivers to knock down and overexpress dSir2 in a tissue-specific manner. A diet-dependent life span phenotype of dSir2 perturbations (both knockdown and overexpression) in the fat body, but not muscles, negates the effects of background genetic mutations. In addition to providing clarity to the field, our study contrasts the ability of dSir2 in two metabolic tissues to affect longevity. We also show that dSir2 knockdown abrogates fat-body dFOXO-dependent life span extension. This report highlights the importance of the interplay between genetic factors and dietary inputs in determining organismal life spans. PMID:23246004

Banerjee, Kushal Kr; Ayyub, Champakali; Ali, Syed Zeeshan; Mandot, Vinesh; Prasad, Nagaraj G; Kolthur-Seetharam, Ullas

2012-12-13

316

Genetic analysis of extended life span in Drosophila melanogaster II. Replication of the backcross test and molecular characterization of the N14 Locus  

Microsoft Academic Search

We are interested in localizing chromosomal regions that extend life span in Drosophila. Using stocks artificially selected\\u000a for long life by Luckinbill and his colleagues, we have identified marker loci that are highly divergent in allelic frequencies\\u000a between replicated long-lived lines and controls (Curtsinger et al., 1998). Several of the most divergent loci have been found\\u000a to be associated with

Amy S. Resler; Kristi Kelly; Geri Kantor; Aziz A. Khazaeli; Marc Tatar; James W. Curtsinger

1998-01-01

317

Expression of the E6 and E7 Genes of Human Papillomavirus (HPV16) Extends the Life Span of Human Myoblasts  

Microsoft Academic Search

Primary human myoblasts (satellite cells), like other human cells, have a limited life spanin vitro.Here we show that expression of the E6E7 early region from human papillomavirus type 16 can greatly extend the life span of both fetal and satellite cell-derived myoblasts and release them from dependence on the growth factors normally necessary for their proliferation. Expression of either the

Hanns Lochmüller; Timothy Johns; Eric A. Shoubridge

1999-01-01

318

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

PubMed

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

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

2011-04-21

319

Reproductive conflict and the separation of reproductive generations in humans  

PubMed Central

An enduring puzzle of human life history is why women cease reproduction midway through life. Selection can favor postreproductive survival because older females can help their offspring to reproduce. But the kin-selected fitness gains of helping appear insufficient to outweigh the potential benefits of continued reproduction. Why then do women cease reproduction in the first place? Here, we suggest that early reproductive cessation in humans is the outcome of reproductive competition between generations, and we present a simple candidate model of how this competition will be resolved. We show that among primates exhibiting a postreproductive life span, humans exhibit an extraordinarily low degree of reproductive overlap between generations. The rapid senescence of the human female reproductive system coincides with the age at which, in natural fertility populations, women are expected to encounter reproductive competition from breeding females of the next generation. Several lines of evidence suggest that in ancestral hominids, this younger generation typically comprised immigrant females. In these circumstances, relatedness asymmetries within families are predicted to give younger females a decisive advantage in reproductive conflict with older females. A model incorporating both the costs of reproductive competition and the benefits of grandmothering can account for the timing of reproductive cessation in humans and so offers an improved understanding of the evolution of menopause.

Cant, Michael A.; Johnstone, Rufus A.

2008-01-01

320

Evaluation of platelet thromboxane radioimmunoassay method to measure platelet life-span: Comparison with /sup 111/indium-platelet method  

SciTech Connect

The platelet activation during radiolabeling in vitro with Cr-51 and In-111 may affect the platelet life-span (PLS) in vivo. A new RIA method to measure PLS is being evaluated. Aspirin inhibits platelet thromboxane (TxA/sub 2/) by acetylating cyclooxygenase. The time required for the TxA/sub 2/ levels to return towards control values depends on the rate of new platelets entering circulation and is a measure of PLS. A single dose of aspirin (150mg) was given to 5 normal human subjects. Blood samples were collected for 2 days before aspirin and daily for 10 days. TxA/sub 2/ production in response to endogenous thrombin was studied by allowing 1 ml blood sample to clot at 37/sup 0/C for 90 min. Serum TxB/sub 2/ (stable breakdown product of Tx-A/sub 2/) levels determined by RIA technique. The plot of TxB/sub 2/ levels (% control) against time showed a gradual increase. The PLS calculated by linear regression analysis assuming a 2-day lag period before cyclooxygenase recovery is 9.7 +- 2.37. In the same 5 subjects, platelets from a 50ml blood sample were labeled with /sup 111/In-tropolone in 2 ml autologous plasma. Starting at 1 hr after injection of labeled platelets, 10 blood samples were obtained over a 8 day period. The PLS calculated based on a linear regression analysis is 10.2 +. 1.4. The PLS measured from the rate of platelet disappearance from circulation and the rate of platelet regeneration into circulation are quite comparable in normal subjects. TxA/sub 2/ regeneration RIA may provide a method to measure PLS without administering radioactivity to patient.

Vallabhajosula, S.; Machac, J.; Badimon, L.; Lipszyc, H.; Goldsmith, S.J.; Fuster, V.

1985-05-01

321

Disturbances in the Secretion of Neurotransmitters in IA-2/IA-2? Null Mice: Changes in Behavior, Learning and Life Span  

PubMed Central

Islet-associated protein 2 (IA-2) and IA-2? are major autoantigens in type 1 diabetes and transmembrane proteins in dense core secretory vesicles (DCV) of neuroendocrine cells. The deletion of these genes results in a decrease in insulin secretion. The present study was initiated to test the hypothesis that this deletion not only affects the secretion of insulin, but has a more global effect on neuroendocrine secretion that leads to disturbances in behavior and learning. Measurement of neurotransmitters showed that norepinephrine, dopamine and serotonin were significantly decreased in the brain of double knockout (DKO) mice (P< 0.05 to <0.001). In tests evaluating anxiety-like behavior and conditioned-learning, the DKO mice showed a highly significant increase in anxiety-like behavior (P<0.01 to <0.001) and impairment of conditioned learning (P<0.01) as compared to WT mice. The DKO mice also displayed an increase in spontaneous and induced seizures (P<0.01) and age-related death. Contrary to the generally held view that IA-2 and IA-2? are expressed exclusively in DCV, subcellular fractionation studies revealed that IA-2?, but not IA-2, co-purifies with fractions rich in synaptic vesicles (SV), and that the secretion of dopamine, GABA and glutamate from the synaptosomes of the DKO mice was significantly decreased as was the number of SV (P<0.01). Taken together, these findings show that IA-2? is present in both DCV and SV, and that the deletion of IA-2/IA-2? has a global effect on the secretion of neurotransmitters. The impairment of secretion leads to behavioral and learning disturbances, seizures and reduced life span.

Nishimura, Takuya; Kubosaki, Atsutaka; Ito, Yoichiro; Notkins, Abner L.

2009-01-01

322

Reproductive health and quality of life of young Burmese refugees in Thailand  

Microsoft Academic Search

BACKGROUND: Of the 140 000 Burmese* refugees living in camps in Thailand, 30% are youths aged 15-24. Health services in these camps do not specifically target young people and their problems and needs are poorly understood. This study aimed to assess their reproductive health issues and quality of life, and identifies appropriate service needs. METHODS: We used a stratified two-stage

Marie T Benner; Joy Townsend; Wiphan Kaloi; Kyi Htwe; Nantarat Naranichakul; Saowalak Hunnangkul; Verena I Carrara; Egbert Sondorp

2010-01-01

323

Reproductive Stage of the Life Cycle in the Rhizocephalan Barnacle Polyascus polygenea (Crustacea: Cirripedia)  

Microsoft Academic Search

The specific features of the reproductive stage of the life cycle have been studied in the rhizocephalan barnacle Polyascus polygenea, a parasite of the coastal crab Hemigrapsus sanguineus. It is shown that a single crab can bear 1 to 8 externae of P. polygenea. The fecundity of the parasite depends on the size of the externae and their number on

O. M. Korn; A. I. Shukalyuk; A. V. Trofimova; V. V. Isaeva

2004-01-01

324

Two Reproductive Life History Types of Kokanee, Onchorynchus nerka , Exhibit Multivariate Morphometric and Protein Genetic Differentiation  

Microsoft Academic Search

Two reproductive types of kokanee are found in Okanagan Lake, British Columbia: one form that spawns in streams, and another that spawns approximately 2–4 weeks later along beaches of the lake. We examined the levels and patterns of genetic and morphometric variation among three populations (1 beach and 2 stream populations) to better understand life history differentiation. We assayed allozyme

Gary A. Winans; Susan Pollard; David R. Kuligowski

2003-01-01

325

Life history of flight morph females of Callosobruchus maculatus F.: evidence of a reproductive diapause.  

PubMed

Callosobruchus maculatus (F.) (Coleoptera : Bruchidae) is a tropical beetle that develops in the seeds of Vigna unguiculata. C. maculatus adults show an imaginal polymorphism with differences in morphological, behavioral and reproductive characteristics. Adults of the flight morph that emerge in cowpea storage systems were studied under natural climatic conditions. A large number of the flight morph females were in reproductive diapause and had a long imaginal life. These females did not synthesize vitellogenin, produced a specific diapause protein and possessed significant protein reserves. This suggests that the beetles survived in the tropical ecosystem for a long time and colonized the crops during the cowpea growing and flowering phases. Analysis of reproductive activity in females captured in the V. unguiculata crops indicates that they terminated their reproductive diapause and began to lay eggs as soon as the pods were formed. Few females of the flight morph were sexually active at the beginning of imaginal life. In this paper we discuss the adaptive significance of these two reproductive strategies in females of C. maculatus. PMID:12804717

Zannou, E T; Glitho, I A; Huignard, J; Monge, J P

2003-06-01

326

Life history context of reproductive aging in a wild primate model  

PubMed Central

The pace of reproductive aging has been of considerable interest, especially in regard to the long postreproductive period in modern women. Here we use data for both sexes from a 37-year longitudinal study of a wild baboon population to place reproductive aging within a life history context for this species, a primate relative of humans that evolved in the same savannah habitat as humans did. We examine the patterns and pace of reproductive aging, including birth rates and reproductive hormones for both sexes, and compare reproductive aging to age-related changes in several other traits. Reproductive senescence occurs later in baboon females than males. Delayed senescence in females relative to males is also found in several other traits, such as dominance status and body condition, but not in molar wear or glucocorticoid profiles. Survival, health, and well-being are the product of risk factors in morphological, physiological, and behavioral traits that differ in rate of senescence and in dependence on social or ecological conditions; some will be very sensitive to differences in circumstances and others less so.

Altmann, Jeanne; Gesquiere, Laurence; Galbany, Jordi; Onyango, Patrick O.; Alberts, Susan C.

2012-01-01

327

The adaptive value of morphological, behavioural and life-history traits in reproductive female wolves.  

PubMed

Reproduction in social organisms is shaped by numerous morphological, behavioural and life-history traits such as body size, cooperative breeding and age of reproduction, respectively. Little is known, however, about the relative influence of these different types of traits on reproduction, particularly in the context of environmental conditions that determine their adaptive value. Here, we use 14 years of data from a long-term study of wolves (Canis lupus) in Yellowstone National Park, USA, to evaluate the relative effects of different traits and ecological factors on the reproductive performance (litter size and survival) of breeding females. At the individual level, litter size and survival improved with body mass and declined with age (c. 4-5 years). Grey-coloured females had more surviving pups than black females, which likely contributed to the maintenance of coat colour polymorphism in this system. The effect of pack size on reproductive performance was nonlinear as litter size peaked at eight wolves and then declined, and litter survival increased rapidly up to three wolves, beyond which it increased more gradually. At the population level, litter size and survival decreased with increasing wolf population size and canine distemper outbreaks. The relative influence of these different-level factors on wolf reproductive success followed individual > group > population. Body mass was the primary determinant of litter size, followed by pack size and population size. Body mass was also the main driver of litter survival, followed by pack size and disease. Reproductive gains because of larger body size and cooperative breeding may mitigate reproductive losses because of negative density dependence and disease. These findings highlight the adaptive value of large body size and sociality in promoting individual fitness in stochastic and competitive environments. PMID:23043440

Stahler, Daniel R; MacNulty, Daniel R; Wayne, Robert K; vonHoldt, Bridgett; Smith, Douglas W

2012-10-08

328

Differential reproductive responses to stress reveal the role of life-history strategies within a species.  

PubMed

Life-history strategies describe that 'slow'- in contrast to 'fast'-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events. PMID:24089339

Schultner, J; Kitaysky, A S; Gabrielsen, G W; Hatch, S A; Bech, C

2013-10-02

329

Combination of hTERT and bmi-1, E6, or E7 Induces Prolongation of the Life Span of Bone Marrow Stromal Cells from an Elderly Donor without Affecting Their Neurogenic Potential  

Microsoft Academic Search

Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow

Taisuke Mori; Tohru Kiyono; Hideaki Imabayashi; Yukiji Takeda; Kohei Tsuchiya; Shunichirou Miyoshi; Hatsune Makino; Kenji Matsumoto; Hirohisa Saito; Satoshi Ogawa; Michiie Sakamoto; Jun-Ichi Hata; Akihiro Umezawa

2005-01-01

330

Care and the self: biotechnology, reproduction, and the good life  

PubMed Central

This paper explores a novel philosophy of ethical care in the face of burgeoning biomedical technologies. I respond to a serious challenge facing traditional bioethics with its roots in analytic philosophy. The hallmarks of these traditional approaches are reason and autonomy, founded on a belief in the liberal humanist subject. In recent years, however, there have been mounting challenges to this view of human subjectivity, emerging from poststructuralist critiques, such as Michel Foucault's, but increasingly also as a result of advances in biotechnology itself. In the face of these developments, I argue that the theoretical relevance and practical application of mainstream bioethics is increasingly under strain. Traditionalists will undoubtedly resist. Together, professional philosopher-bioethicists, public health policymakers, and the global commercial healthcare industry tend to respond conservatively by shoring up the liberal humanist subject as the foundation for medical ethics and consumer decision-making, appealing to the familiar tropes of reason, autonomy, and freedom. I argue for a different approach to bioethics, and work towards a new way to conceive of ethical relations in healthcare – one that does not presume a sovereign subject as the basis of dignity, personhood or democracy. Instead, I am critical of the narrow instantiations of reason, autonomy, and freedom, which, more recently, have been co-opted by a troubling neo-liberal politics of the self. Thus, I am critical of current trends in medical ethics, often running in tandem with corporate-governmental models of efficiency, accountability, and so-called evidence-based best practices. As an example of such market-driven conceptions of subjectivity, I discuss the paradigm of "self-care." Self-care shores up the traditional view of the self as a free agent. In this sense, self-care is looked upon favourably by mainstream bioethics in its focus on autonomy, while healthcare policy endorses this model for ideological and economic reasons. To contrast this, I propose a different model of care together with a different model of selfhood. Here I develop and apply Foucault's late work on the "care of the self." In this understanding of "care," I suggest that we might work towards an ethical self that is more commensurable both with recent theoretical views on subjectivity and – more pressingly – with the challenges of emergent biotechnologies. I end this paper with a discussion on ethical parenthood, which offers a practical reading of the "care of the self" in relation to new reproductive technologies (NRTs).

Murray, Stuart J

2007-01-01

331

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

PubMed

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. PMID:22528607

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

2012-08-01

332

Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice  

Microsoft Academic Search

Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while\\u000a at the same time live shorter lives. These relationships have been combined in the ‘membrane pacemaker hypothesis of aging’.\\u000a It suggests that membrane PUFA content might determine an animal’s life span. PUFAs in general and certain long-chain PUFAs\\u000a in particular, are highly prone

Teresa G. Valencak; Thomas Ruf

2011-01-01

333

Deletion of the life span determinant p66 Shc prevents age-dependent increases in emotionality and pain sensitivity in mice  

Microsoft Academic Search

Oxidative stress has been implicated in the aging process. Previous studies have determined that mice with a targeted mutation of the p66Shc gene show reduced oxidative stress and extended life span. This study is the first behavioral characterization of mice carrying a deletion of p66Shc. Four-, 11- and 24-months-old homozygous knockout and wild-type mice of the 129Sv\\/Ev strain underwent a

Alessandra Berry; Francesca Capone; Marco Giorgio; Pier Giuseppe Pelicci; E. R. de Kloet; Enrico Alleva; Luisa Minghetti; Francesca Cirulli

2007-01-01

334

Short Article Targeted expression of the human uncoupling protein 2 (hUCP2) to adult neurons extends life span in the fly  

Microsoft Academic Search

Summary The oxidative stress hypothesis of aging predicts that a reduction in the generation of mitochondrial reactive oxygen species (ROS) will decrease oxidative damage and extend life span. Increasing mitochondrial proton leak-dependent state 4 respiration by increasing mitochondrial uncoupling is an intervention postulated to decrease mitochondrial ROS pro- duction. When human UCP2 (hUCP2) is targeted to the mitochondria of adult

Yih-Woei C. Fridell; Adolfo Sánchez-Blanco; Brian A. Silvia; Stephen L. Helfand

335

Global Self-Esteem Across the Life Span: A Cross-Sectional Comparison Between Representative and Self-Selected Internet Samples  

Microsoft Academic Search

The cross-sectional trajectory of global self-esteem across the life span was examined administering the Rosenberg and Single-Item Self-Esteem scales to Estonians (N = 29,463) who were either randomly selected from the National Census to represent the population or self-recruited through the Internet. The results (a) challenge the recent conclusion of a universal age trajectory of self-esteem, (b) demonstrate that self-recruited Internet data

Helle Pullmann; Jüri Allik; Anu Realo

2009-01-01

336

An overview of a multifactor-system theory of personality and individual differences: III. Life span development and the heredity-environment issue  

Microsoft Academic Search

Discusses multivariate life-span development from the standpoint of a quantitative and qualitative analysis of the ontogenesis of factors in each of 6 systems. The pattern of quantitative development involves growth, stability, and decline; and qualitative development involves changes in the organization of factors. Hereditary and environmental sources of variation are analyzed via the factor-gene model and the concept of heredity-dominant

Arnold Powell; Joseph R. Royce

1981-01-01

337

Excess omega-3 fatty acid consumption by mothers during pregnancy and lactation caused shorter life span and abnormal ABRs in old adult offspring.  

PubMed

Consuming omega-3 fatty acids (omega-3 FA) during pregnancy and lactation is beneficial to fetal and infant development and might reduce the incidence and severity of preterm births by prolonging pregnancy. Consequently, supplementing maternal diets with large amounts of omega-3 FA is gaining acceptance. However, both over- and under-supplementation with omega-3 FA can harm offspring development. Adverse fetal and neonatal conditions in general can enhance age-related neural degeneration, shorten life span and cause other adult-onset disorders. We hypothesized that maternal over- and under-nutrition with omega-3 FA would shorten the offspring's life span and enhance neural degeneration in old adulthood. To test these hypotheses, female Wistar rats were randomly assigned to one of the three diet conditions starting from day 1 of pregnancy through the entire period of pregnancy and lactation. The three diets were Control omega-3 FA (omega-3/omega-6 ratio approximately 0.14), Excess omega-3 FA (omega-3/omega-6 ratio approximately 14.5) and Deficient omega-3 FA (omega-3/omega-6 ratio approximately 0% ratio). When possible, one male and female offspring from each litter were assessed for life span and sensory/neural degeneration (n=15 litters/group). The Excess offspring had shorter life spans compared to their Control and Deficient cohorts (mean+/-SEM=506+/-24, 601+/-14 and 585+/-21 days, plife span and sensory/neurological function in old adulthood. The adverse outcomes in the Excess offspring were likely due to a "nutritional toxicity" during fetal and/or neonatal development that programmed them for life-long health disorders. The health implication is that consuming or administering large amounts of omega-3 FA during pregnancy and lactation seems inadvisable because of adverse effects on the offspring. PMID:19818397

Church, M W; Jen, K-L C; Anumba, J I; Jackson, D A; Adams, B R; Hotra, J W

2009-10-07

338

Life History and Reproductive Timing of the Endangered Illinois Cave Amphipod, Gammarus acherondytes  

NASA Astrophysics Data System (ADS)

To aid the recovery of endangered species requires an understanding of their basic biology. Armed with such knowledge, meaningful management plans with realistic objectives can be established. We examined the life history and reproductive biology of Gammarus acherondytes, a federally endangered cave amphipod, in Reverse Stream, Monroe Co., Illinois. The population was sampled non-destructively at monthly intervals from October 2003 to February 2005. The density of gravid females peaked twice annually, (November-December and June-July) indicating major reproductive events. Gravid females also occurred at other times of the year but at low densities. Two major peaks in the density of newborn young were also observed, which lagged the density of gravid females by approximately 1-2 months. We believe this reproductive pattern is related to the influx of organic matter from mid summer storm events and leaf abscission in autumn. Young grew at a rate of 0.034 mm/day and likely reach reproductive size in one year. Adults are iteroparous and may live for several years. Our results suggest that limiting cave access in highly visited caves during peak reproduction may be a simple strategy to increase the abundance of G. acherondytes.

Venarsky, M. P.; Wilhelm, F. M.; Anderson, F. A.; Taylor, S. J.

2005-05-01

339

Analysis of menstrual, reproductive, and life-style factors for breast cancer risk in Turkish women  

Microsoft Academic Search

The aim of this study was to investigate the association between menstrual, reproductive, and life-style factors and breast\\u000a cancer in Turkish women. In a hospital-based case-control study in Ankara, 622 patients with histologically confirmed breast\\u000a cancer were compared with 622 age-matched controls, admitted to the same hospital for acute and non-neoplastic diseases. Unconditional\\u000a logistic regression was used to estimate odds

Betul Oran; Ismail Celik; Mustafa Erman; Esmen Baltali; Nurullah Zengin; Figen Demirkazik; Sabahat Tezcan

2004-01-01

340

The reproductive cycle and life history of the Arctic copepod Calanus glacialis in the White Sea  

Microsoft Academic Search

Seasonal variations in the gonad development and sex ratio of copepodite stage V (CV) and adults were examined from February\\u000a to November in order to understand the reproductive cycle and the life history of Calanus glacialis in the White Sea. Gonad maturation, sexual differentiation and moulting to adults take place during the 2nd year of development.\\u000a Energy accumulation takes place

K. N. Kosobokova

1999-01-01

341

Life History Evolution of Virtual Plants: Trading Off Between Growth and Reproduction  

Microsoft Academic Search

Abstract. This paper presents studies on the life history evolution of plants carried out by experimenting with a multi-agent platform of generic virtual plants. The conducted simulations address the trade-o between resource allocation to vegetative and reproductive structures. The trade-o,is pointed out by evolutionary runs selecting for one of the two traits. It is further shown that the introduction of

Stefan Bornhofen; Claude Lattaud

2006-01-01

342

Reproductive life history correlates of early and late sexual maturation in female Mongolian gerbils (Meriones unguiculatus)  

Microsoft Academic Search

Age at vaginal introitus is bimodally distributed in female domesticated Mongolian gerbils; some exhibit vaginal perforation before eye-opening (day 16), others after weaning (day 25). We found early- and late-maturing female gerbils to ditfer significantly in reproductive life history. Early-maturing females first reproduced when younger. had more litters, with more young per litter, and consequently had more than twice as

MERTICE M. CLARK; CHERYL A. SPENCER; B GALEFJR

1986-01-01

343

THE NUTRITIONAL VALUE OF A SYNTHETIC DIET STERILIZED BY GAMMA RAYS, AS MEASURED BY REPRODUCTION AND LIFE SPAN OF RATS  

Microsoft Academic Search

The Officeof the Surgeon General of U. S. Army has carried out an investigation to determine the nutritional properties of foods which have been sterilized by gamma radiation from fis sion products. This laboratory has participated in this over all program on radiation preservation of foods since Septem ber 1954. One study in the program was to determine the nutritional

LUTHER R. RICHARDSOX; ANDRUTH BROCK

344

Vegetable oils high in phytosterols make erythrocytes less deformable and shorten the life span of stroke-prone spontaneously hypertensive rats.  

PubMed

Previous studies have shown that canola oil (CA), compared with soybean oil (SO), shortens the life span of stroke-prone spontaneously hypertensive (SHRSP) rats, a widely used model for hemorrhagic stroke. SHRSP rats are highly sensitive to dietary cholesterol manipulations because a deficiency of membrane cholesterol makes their cell membranes weak and fragile. Phytosterols, abundant in CA but not in SO, can inhibit the absorption of cholesterol and also replace a part of cholesterol in cell membranes. This study was performed to determine whether the high concentration of phytosterols in CA might account for its life-shortening effect on SHRSP rats. Male, 35-d-old SHRSP rats (n = 28/group) were fed semipurified diets containing CA, SO, CA fortified with phytosterols (canola oil + phytosterols, CA + P), SO fortified with phytosterols (soybean oil + phytosterols, SO + P), corn oil (CO), olive oil (OO) or a fat blend that mimicked the fat composition of a representative Canadian diet (Canadian fat mimic, CFM; 10 g/100 g diet). These fats provided 97, 36, 207, 201, 114, 27 and 27 mg phytosterols/100 g diet, respectively. Ten rats from each group were killed after 30-32 d for blood and tissue analyses. The remaining rats (18/group) were used for determination of life span. The life span of SHRSP rats fed the high phytosterol oils (CA, CA + P, SO + P and CO) was significantly (P<0.05) shorter than that of CFM- and SO-fed rats. At 30-32 d, the groups fed the high phytosterol oils had greater levels of phytosterols and significantly (P<0.05) higher ratios of phytosterols/cholesterol in plasma, RBC, liver and kidney, and a significantly (P<0.05) lower RBC membrane deformabilty index than the groups fed oils low in phytosterols (SO, OO and CFM). The mean survival times were correlated with RBC deformability index (r(2) = 0.91, P = 0.0033) and cholesterol concentration (r(2) = 0.94, P = 0.0016), and inversely correlated with RBC phytosterol concentration (r(2) = 0.58, P = 0.0798) and phytosterols/cholesterol (r(2) = 0.65, P = 0.0579), except in the OO group. This study suggests that the high concentration of phytosterols in CA and the addition of phytosterols to other fats make the cell membrane more rigid, which might be a factor contributing to the shortened life span of SHRSP rats. PMID:10801914

Ratnayake, W M; L'Abbé, M R; Mueller, R; Hayward, S; Plouffe, L; Hollywood, R; Trick, K

2000-05-01

345

Rapid weight gain after birth predicts life history and reproductive strategy in Filipino males  

PubMed Central

Ecological cues during prenatal and postnatal development may allow organisms to adjust reproductive strategy. The hypothalamic-pituitary-gonadal (HPG) axis is a prime candidate for adaptive plasticity as a result of its critical period of birth to 6 mo (B6M) in humans and the role of testosterone in the development and maintenance of costly sexually dimorphic somatic and behavioral traits. We hypothesized that weight velocity specific to B6M would predict male life history characteristics, including maturational timing, reproductive hormones, adult size, strength, and sexual activity. Data come from 770 Filipino men (age 20.5–22.5 y) followed since birth, with predictor variables including birth weight and weight velocities calculated at 6-mo intervals during the first 2 y of life. As expected, infants who were breastfed experienced less diarrhea, lived in wealthier households with better hygiene, and grew faster from B6M. Males with rapid B6M growth reached puberty earlier and, as young adults, had higher testosterone levels, were taller, more muscular, and had higher grip strength. They also had sex earlier and were more likely to report having had sex in the past month, resulting in more lifetime sex partners. Relationships between B6M weight gain and physical outcomes were generally not present or weaker in female subjects. We conclude that rapid weight gain specific to the brief postnatal hypothalamic-pituitary-gonadal critical period predicts early maturation and sexual activity, elevated hormone production, and more costly adult somatic characteristics among the male subjects in this sample. These findings provide evidence for early life developmental plasticity in male life history and reproductive strategy in humans.

Kuzawa, Christopher W.; McDade, Thomas W.; Adair, Linda S.; Lee, Nanette

2010-01-01

346

Reproductive strategies and Islamic discourse: Malian migrants negotiate everyday life in Paris, France.  

PubMed

Approximately 37 thousand Malians currently reside in France as part of the West African diaspora. Primarily Muslim, both women and men confront challenges to their understandings of Islamic prohibitions and expectations, especially those addressing conjugal relations and reproduction. Biomedical policies generate marital conflicts and pose health dilemmas for women who face family and community pressures to reproduce but biomedical encouragement to limit childbearing. For many women, contraception represents a reprieve from repeated pregnancies and fatigue in spite of resistance from those who contest women's reproductive decisions as antithetical to Islam. French social workers play a particularly controversial role by introducing women to a discourse of women's rights that questions the authority of husbands and of religious doctrine. Women and men frame decisions and debate in diverse interpretations of Islam as they seek to manage the contradictions of everyday life and assert individual agency in the context of immigration and health politics. PMID:16612992

Sargent, Carolyn F

2006-03-01

347

Against the oxidative damage theory of aging: superoxide dismutases protect against oxidative stress but have little or no effect on life span in Caenorhabditis elegans  

PubMed Central

The superoxide radical (O2?) has long been considered a major cause of aging. O2? in cytosolic, extracellular, and mitochondrial pools is detoxified by dedicated superoxide dismutase (SOD) isoforms. We tested the impact of each SOD isoform in Caenorhabditis elegans by manipulating its five sod genes and saw no major effects on life span. sod genes are not required for daf-2 insulin/IGF-1 receptor mutant longevity. However, loss of the extracellular Cu/ZnSOD sod-4 enhances daf-2 longevity and constitutive diapause, suggesting a signaling role for sod-4. Overall, these findings imply that O2? is not a major determinant of aging in C. elegans.

Doonan, Ryan; McElwee, Joshua J.; Matthijssens, Filip; Walker, Glenda A.; Houthoofd, Koen; Back, Patricia; Matscheski, Andrea; Vanfleteren, Jacques R.; Gems, David

2008-01-01

348

Cell proliferation dynamics of somatic and germline tissues during zooidal life span in the colonial tunicate Botryllus primigenus.  

PubMed

Botryllus primigenus is a colonial tunicate in which three successive generations develop synchronously. To identify proliferation centers and possible adult stem cells during asexual reproduction, somatic and germline cells were labeled with 5-bromo-2'-deoxyuridine (BrdU). In the youngest generation, multipotent epithelial cells exhibited an average labeling index (LI) of 30% 24 hr after BrdU injection. In the middle generation, the LI of organ rudiments decreased gradually and reached zero by the beginning of the eldest generation. Exceptionally, cells of specialized tissues such as the pharyngeal inner longitudinal vessel and the posterior end of the endostyle continued DNA synthesis and mitosis even in the eldest generation. Proliferating somatic and germline cells of younger generations expressed a Botryllus myc homolog (BpMyc), but adult tissues did not. This result strongly suggests that in B. primigenus undifferentiated progenitor cells are discernible from possible adult stem cells by the presence or absence of BpMyc. PMID:18570248

Kawamura, Kazuo; Tachibana, Miki; Sunanaga, Takeshi

2008-07-01

349

Human telomerase reverse transcriptase and glucose-regulated protein 78 increase the life span of articular chondrocytes and their repair potential  

PubMed Central

Background Like all mammalian cells, normal adult chondrocytes have a limited replicative life span, which decreases with age. To facilitate the therapeutic use of chondrocytes from older donors, a method is needed to prolong their life span. Methods We transfected chondrocytes with hTERT or GRP78 and cultured them in a 3-dimensional atelocollagen honeycomb-shaped scaffold with a membrane seal. Then, we measured the amount of nuclear DNA and glycosaminoglycans (GAGs) and the expression level of type II collagen as markers of cell proliferation and extracellular matrix formation, respectively, in these cultures. In addition, we allografted this tissue-engineered cartilage into osteochondral defects in old rabbits to assess their repair activity in vivo. Results Our results showed different degrees of differentiation in terms of GAG content between chondrocytes from old and young rabbits. Chondrocytes that were cotransfected with hTERT and GRP78 showed higher cellular proliferation and expression of type II collagen than those of nontransfected chondrocytes, regardless of the age of the cartilage donor. In addition, the in vitro growth rates of hTERT- or GRP78-transfected chondrocytes were higher than those of nontransfected chondrocytes, regardless of donor age. In vivo, the tissue-engineered cartilage implants exhibited strong repairing activity, maintained a chondrocyte-specific phenotype, and produced extracellular matrix components. Conclusions Focal gene delivery to aged articular chondrocytes exhibited strong repairing activity and may be therapeutically useful for articular cartilage regeneration.

2012-01-01

350

The nucleus- and endoplasmic reticulum-targeted forms of protein tyrosine phosphatase 61F regulate Drosophila growth, life span, and fecundity.  

PubMed

The protein tyrosine phosphatases (PTPs) T cell PTP (TCPTP) and PTP1B share a high level of catalytic domain sequence and structural similarity yet display distinct differences in substrate recognition and function. Their noncatalytic domains contribute to substrate selectivity and function by regulating TCPTP nucleocytoplasmic shuttling and targeting PTP1B to the endoplasmic reticulum (ER). The Drosophila TCPTP/PTP1B orthologue PTP61F has two variants with identical catalytic domains that are differentially targeted to the ER and nucleus. Here we demonstrate that the PTP61F variants differ in their ability to negatively regulate insulin signaling in vivo, with the nucleus-localized form (PTP61Fn) being more effective than the ER-localized form (PTP61Fm). We report that PTP61Fm is reliant on the adaptor protein Dock to attenuate insulin signaling in vivo. Also, we show that the PTP61F variants differ in their capacities to regulate growth, with PTP61Fn but not PTP61Fm attenuating cellular proliferation. Furthermore, we generate a mutant lacking both PTP61F variants, which displays a reduction in median life span and a decrease in female fecundity, and show that both variants are required to rescue these mutant phenotypes. Our findings define the role of PTP61F in life span and fecundity and reinforce the importance of subcellular localization in mediating PTP function in vivo. PMID:23339871

Buszard, Bree J; Johnson, Travis K; Meng, Tzu-Ching; Burke, Richard; Warr, Coral G; Tiganis, Tony

2013-01-22

351

Preserving Syntactic Processing across the Adult Life Span: The Modulation of the Frontotemporal Language System in the Context of Age-Related Atrophy  

PubMed Central

Although widespread neural atrophy is an inevitable consequence of normal aging, not all cognitive abilities decline as we age. For example, spoken language comprehension tends to be preserved, despite atrophy in neural regions involved in language function. Here, we combined measures of behavior, functional activation, and gray matter (GM) change in a younger (19–34 years) and older group (49–86 years) of participants to identify the mechanisms leading to preserved language comprehension across the adult life span. We focussed primarily on syntactic functions because these are strongly left lateralized, providing the potential for contralateral recruitment. In an functional magnetic resonance imaging study, we used a word-monitoring task to minimize working memory demands, manipulating the availability of semantics and syntax to ask whether syntax is preserved in aging because of the functional recruitment of other brain regions, which successfully compensate for neural atrophy. Performance in the older group was preserved despite GM loss. This preservation was related to increased activity in right hemisphere frontotemporal regions, which was associated with age-related atrophy in the left hemisphere frontotemporal network activated in the young. We argue that preserved syntactic processing across the life span is due to the shift from a primarily left hemisphere frontotemporal system to a bilateral functional language network.

Shafto, Meredith A.; Randall, Billi; Wright, Paul; Marslen-Wilson, William D.; Stamatakis, Emmanuel A.

2010-01-01

352

The Nucleus- and Endoplasmic Reticulum-Targeted Forms of Protein Tyrosine Phosphatase 61F Regulate Drosophila Growth, Life Span, and Fecundity  

PubMed Central

The protein tyrosine phosphatases (PTPs) T cell PTP (TCPTP) and PTP1B share a high level of catalytic domain sequence and structural similarity yet display distinct differences in substrate recognition and function. Their noncatalytic domains contribute to substrate selectivity and function by regulating TCPTP nucleocytoplasmic shuttling and targeting PTP1B to the endoplasmic reticulum (ER). The Drosophila TCPTP/PTP1B orthologue PTP61F has two variants with identical catalytic domains that are differentially targeted to the ER and nucleus. Here we demonstrate that the PTP61F variants differ in their ability to negatively regulate insulin signaling in vivo, with the nucleus-localized form (PTP61Fn) being more effective than the ER-localized form (PTP61Fm). We report that PTP61Fm is reliant on the adaptor protein Dock to attenuate insulin signaling in vivo. Also, we show that the PTP61F variants differ in their capacities to regulate growth, with PTP61Fn but not PTP61Fm attenuating cellular proliferation. Furthermore, we generate a mutant lacking both PTP61F variants, which displays a reduction in median life span and a decrease in female fecundity, and show that both variants are required to rescue these mutant phenotypes. Our findings define the role of PTP61F in life span and fecundity and reinforce the importance of subcellular localization in mediating PTP function in vivo.

Buszard, Bree J.; Johnson, Travis K.; Meng, Tzu-Ching; Burke, Richard

2013-01-01

353

Adenovirus type 12 early region 1B 54K protein significantly extends the life span of normal mammalian cells in culture.  

PubMed Central

The life span of normal human cells in culture is extended by two to four total life spans following retrovirus-mediated transfer of the adenovirus type 12 E1B 54,000-molecular-weight protein (54K protein). This extension of the in vitro growth potential was accomplished without any of the obvious changes in morphology or growth properties that are usually associated with viral transformation. These 54K+ cells escape the normal senescence checkpoint (M1) and show a very extended secondary growth phase. The 54K+ human cells eventually enter crisis (M2), which does not appear to be due to either telomere attrition or the activation of the senescence-associated proteins p21SdilCipIWaf1 and p16INK4A. Even in the absence of telomerase activity, high-molecular-weight heterogeneous telomeres are produced and maintained in both 54K+ adult dermal fibroblasts and embryo kidney cells, indicating that the 54K protein may interfere with the normal metabolism of telomeric structures during cell division. These findings are discussed with reference to the known ability of the 54K protein to influence p53 function.

Gallimore, P H; Lecane, P S; Roberts, S; Rookes, S M; Grand, R J; Parkhill, J

1997-01-01

354

Much more than a gene: hereditary breast and ovarian cancer, reproductive choices and family life.  

PubMed

This article presents the results of a study that investigates the way in which carriers of a mutation on the BRCA1 or the BRCA2 gene, associated with a high risk of breast and ovarian cancer, make their reproductive decisions. Using semi-structured interviews, the study explored the way in which these persons reflected on the acceptability of taking the risk of transmitting this mutation to the next generation, the arguments they used in favor or against taking that risk, and in the light of these arguments, their opinion on the acceptability of preimplantation genetic diagnosis (PGD) as a reproductive option. The findings suggest that when carriers are planning to have a(nother) child, they are mainly concerned by the risk of transmitting 'much more than a gene': essentially painful experiences not only with respect to health, such as undergoing cancer surveillance or combatting one's own illness, but also with regards to family life, such as witnessing the illness and death of a close relative, encountering difficulties in finding a partner or reconsidering one's plans to have a family. As for opinions concerning the acceptability of PGD as a reproductive option, opinions about personal recourse were varied but all expressed the understanding that PGD should be made available to those persons who consider it their best option. PMID:22048863

Dekeuwer, Catherine; Bateman, Simone

2013-05-01

355

Life Span of C57 Mice as Influenced by Radiation Dose, Dose Rate, and Age at Exposure.  

National Technical Information Service (NTIS)

This study was designed to measure the life shortening of C57BL/6J male mice as a result of exposure to five external doses from exp 60 Co gamma radiation delivered at six different dose rates. Total doses ranged from 20 to 1620 rad at exposure rates rang...

J. F. Spalding R. G. Thomas G. L. Tietjen

1982-01-01

356

Clara Schumann's collection of playbills: A historiometric analysis of life-span development, mobility, and repertoire canonization  

Microsoft Academic Search

Clara Schumann's (1819–1896) important influence on concert life and piano performance throughout the 19th century can still be felt in our times. Virtually all concerts Clara gave between 1828 (at age 9) and 1891 (at age 71) are documented in a historically unique collection of over 1300 printed concert program leaflets (playbills). Combining an historiometric approach with musicological methods, we

Reinhard Kopiez; Andreas C. Lehmann; Janina Klassen

2009-01-01

357

Dead or alive: Deformed Wing Virus and Varroa destructor reduce the life span of winter honey bees  

Technology Transfer Automated Retrieval System (TEKTRAN)

Elevated winter losses of managed honey bee colonies are a major concern, but the underlying mechanisms remain controversial. Among suspects are the parasitic mite Varroa destructor, the microsporidian Nosema ceranae and associated viruses. Here, we hypothesize that pathogens reduce the life expecta...

358

Ecological volatility and human evolution: a novel perspective on life history and reproductive strategy.  

PubMed

Humans are characterized by a suite of traits that seem to differentiate them profoundly from closely related apes such as the gorilla, chimpanzee, and orang-utan. These traits include longevity, cooperative breeding, stacking of offspring, lengthy maturation, and a complex life-course profile of adiposity. When, how, and why these traits emerged during our evolutionary history is currently attracting considerable attention. Most approaches to life history emphasize dietary energy availability and the risk of mortality as the two key stresses shaping life-history variability between and within species. The high energy costs of the large Homo brain are also seen as the central axis around which other life-history traits were reorganized. I propose that ecological volatility may have been a key stress, selecting in favor of the suite of traits in order to tolerate periods of energy scarcity, and increase reproductive output during periods of good conditions. Theses life-history adaptations may have preceded and enabled the trend toward encephalization. PMID:23280924

Wells, Jonathan C K

2012-11-01

359

Predicting trait values and measuring selection in complex life histories: reproductive allocation decisions in Soay sheep.  

PubMed

Accurate prediction of life history phenomena and characterisation of selection in free-living animal populations are fundamental goals in evolutionary ecology. In density regulated, structured populations, where individual state influences fate, simple and widely used approaches based on individual lifetime measures of fitness are difficult to justify. We combine recently developed structured population modelling tools with ideas from modern evolutionary game theory (adaptive dynamics) to understand selection on allocation of female reproductive effort to singletons or twins in a size-structured population of feral sheep. In marked contrast to the classical selection analyses, our model-based approach predicts that the female allocation strategy is under negligible directional selection. These differences arise because classical selection analysis ignores components of offspring fitness and fails to consider selection over the complete life cycle. PMID:21790931

Childs, D Z; Coulson, T N; Pemberton, J M; Clutton-Brock, T H; Rees, M

2011-07-26

360

Life span extension by resveratrol, rapamycin, and metformin: The promise of dietary restriction mimetics for an healthy aging.  

PubMed

Life expectancy at the turn of the 20th century was 46 years on average worldwide and it is around 65 years today. The correlative increase in age-associated diseases incidence has a profound public health impact and is an important matter of concern for our societies. Aging is a complex, heterogeneous, and multifactorial phenomenon, which is the consequence of multiple interactions between genes and environment. In this review, we survey animals models that have been of great help for both investigating mechanism of aging and identifying molecules, which slow down the onset of age-related diseases. Resveratrol (RSV) is one of those. We will report evidences supporting RSV as a molecule that acts by mimicking the beneficial effects of dietary restriction, and may share common downstream targets with rapamycin and metformin. Although those molecules do not reveal all the secrets of the fountain of youth, they may help us maintaining the quality of life in the old age. PMID:20848587

Mouchiroud, Laurent; Molin, Laurent; Dallière, Nicolas; Solari, Florence

361

Genetic analysis of extended life span in Drosophila melanogaster I. RAPD screen for genetic divergence between selected and control lines  

Microsoft Academic Search

Using lines selected for long life by Luckinbill and his co-workers, we screened two selected and two control lines for allelic\\u000a frequency differences at 1200 randomly chosen RAPD marker loci. Twenty-three marker loci showed frequency differences in excess\\u000a of 80%, and five were greater than 90%. Age-specific effects of the five most differentiated loci were estimated by collecting\\u000a complete survival

James W. Curtsinger; Hank H. Fukui; Amy S. Resler; Kristi Kelly; Aziz A. Khazaeli

1998-01-01

362

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

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…

Staudinger, Ursula M.

363

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

|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…

Staudinger, Ursula M.

364

The Tölz Temporal Topography Study: mapping the visual field across the life span. Part I: the topography of light detection and temporal-information processing.  

PubMed

Temporal performance parameters vary across the visual field. Their topographical distributions relative to each other and relative to basic visual performance measures and their relative change over the life span are unknown. Our goal was to characterize the topography and age-related change of temporal performance. We acquired visual field maps in 95 healthy participants (age: 10-90 years): perimetric thresholds, double-pulse resolution (DPR), reaction times (RTs), and letter contrast thresholds. DPR and perimetric thresholds increased with eccentricity and age; the periphery showed a more pronounced age-related increase than the center. RT increased only slightly and uniformly with eccentricity. It remained almost constant up to the age of 60, a marked change occurring only above 80. Overall, age was a poor predictor of functionality. Performance decline could be explained only in part by the aging of the retina and optic media. In Part II, we therefore examine higher visual and cognitive functions. PMID:22484795

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

2012-08-01

365

Reproductive problems directly attributable to long-term captivity--asymmetric reproductive aging.  

PubMed

Problems attributable to long-term captivity have been identified and are responsible for the difficulties in establishing successful reproduction in captive populations of wildlife, specifically, elephants and rhinoceroses. Historically, non-reproductive periods of 10-15 years in nulliparous female rhinoceroses and elephants have not been considered problematic. New evidence suggests that prolonged exposure to endogenous sex steroids and that long stretches of non-reproductive periods induce asymmetric reproductive aging in captive animals. The consequences are reduced fertility, shortened reproductive life-span and, eventually, irreversible acyclicity. Although age-related reproductive lesions have also been documented in male rhinoceroses, they continue to maintain a longer reproductive life-span than females. Since human and domestic animal models have already indicated that early pregnancy provides natural protective mechanism against asymmetric reproductive aging processes and premature senescence, it is imperative that appropriate counter measures such as assisted reproductive technologies (ART) be utilized to ensure early pregnancy in captive animals for their preservation and to ensure increased genetic diversity of the captive populations. PMID:15271443

Hermes, R; Hildebrandt, T B; Göritz, F

2004-07-01

366

Relevance of NAC-2, an Na+-coupled citrate transporter, to life span, body size and fat content in Caenorhabditis elegans.  

PubMed Central

We have cloned and functionally characterized an Na+-coupled citrate transporter from Caenorhabditis elegans (ceNAC-2). This transporter shows significant sequence homology to Drosophila Indy and the mammalian Na+-coupled citrate transporter NaCT (now known as NaC2). When heterologously expressed in a mammalian cell line or in Xenopus oocytes, the cloned ceNAC-2 mediates the Na+-coupled transport of various intermediates of the citric acid cycle. However, it transports the tricarboxylate citrate more efficiently than dicarboxylates such as succinate, a feature different from that of ceNAC-1 (formerly known as ceNaDC1) and ceNAC-3 (formerly known as ceNaDC2). The transport process is electrogenic, as evidenced from the substrate-induced inward currents in oocytes expressing the transporter under voltage-clamp conditions. Expression studies using a reporter-gene fusion method in transgenic C. elegans show that the gene is expressed in the intestinal tract, the organ responsible for not only the digestion and absorption of nutrients but also for the storage of energy in this organism. Functional knockdown of the transporter by RNAi (RNA interference) not only leads to a significant increase in life span, but also causes a significant decrease in body size and fat content. The substrates of ceNAC-2 play a critical role in metabolic energy production and in the biosynthesis of cholesterol and fatty acids. The present studies suggest that the knockdown of these metabolic functions by RNAi is linked to an extension of life span and a decrease in fat content and body size.

Fei, You-Jun; Liu, Jin-Cai; Inoue, Katsuhisa; Zhuang, Lina; Miyake, Katsuya; Miyauchi, Seiji; Ganapathy, Vadivel

2004-01-01

367

Reproductive versus somatic tissue growth during the life cycle of the cuttlefish Sepia pharaonis Ehrenberg, 1831  

Microsoft Academic Search

The effect of maturation on relative growth of somatic tissues was investigated by measuring and compar- ing monthly changes in dry weight of somatic tissues and reproductive or- gans. In both sexes, reproductive tis- sues grew in relation to total body mass; at maturity female reproductive tissue was 16% of total dry body mass, whereas male reproductive tissue was 2.6%.

Howaida R. Gabr; Roger T. Hanlon; Salah G. El-Etreby; Mahmoud H. Hanafy

368

Reproductive cycle-associated mood symptoms in women with major depression and bipolar disorder  

Microsoft Academic Search

BackgroundWe sought to determine the prevalence of, and association between, reproductive cycle-associated mood symptoms in women with affective disorders. We hypothesized that symptoms would correlate with each other across a woman's reproductive life span in both major depression (MDD) and bipolar I disorder (BP).

Jennifer L. Payne; Patricia S. Roy; Kathleen Murphy-Eberenz; Myrna M. Weismann; Karen L. Swartz; Melvin G. McInnis; Eva Nwulia; Francis M. Mondimore; Dean F. MacKinnon; Erin B. Miller; John I. Nurnberger; Douglas F. Levinson; J. Raymond DePaulo; James B. Potash

2007-01-01

369

Testing for genetic trade-offs between early- and late-life reproduction in a wild red deer population  

Microsoft Academic Search

The antagonistic pleiotropy (AP) theory of ageing predicts genetically based trade-offs between investment in reproduction in early life and survival and performance in later life. Laboratory-based research has shown that such genetic trade-offs exist, but little is currently known about their prevalence in natural populations. We used random regression 'animal model' techniques to test the genetic basis of trade-offs between

Daniel H. Nussey; Alastair J. Wilson; Alison Morris; Josephine Pemberton; Tim Clutton-Brock; Loeske E. B. Kruuk

2008-01-01

370

Stereotypes of Women in Different Stages of Their Reproductive Life: Data From Mexico and the United States  

Microsoft Academic Search

College students from Mexico and the United States (n = 349) were surveyed to explore stereotypes regarding women in different menstrual cycle phases and other stages of reproductive life. Participants from both countries defined a premenstrual or menstrual woman as irritable and moody and a menopausal woman as old and irritable. A woman with a hysterectomy was defined as sad,

Ma. Luisa Marván; Martha Islas; Laura Vela; Joan C. Chrisler; Elyse A. Warren

2008-01-01

371

LIFE HISTORY AND REPRODUCTIVE BIOLOGY OF THE GILGIE, CHERAX QUINQUECARINATUS, A FRESHWATER CRAYFISH ENDEMIC TO SOUTHWESTERN AUSTRALIA  

Microsoft Academic Search

The gilgie, Cherax quinquecarinatus, a freshwater crayfish endemic to southwestern Western Australia, occupies a wide range of permanent and temporary aquatic environments. Reproductive and population biology parameters were determined in Bull Creek, southwestern Western Australia. Crayfish were collected monthly from May 2002 to April 2003. The seasonal von Bertalanffy growth curve, fitted for the first 14 months of life for

Stephen J. Beatty; David L. Morgan; Howard S. Gill

2005-01-01

372

Complex life cycles: why refrain from growth before reproduction in the adult niche?  

PubMed

Organisms with complex life cycles occupy distinct niches as larvae and adults. One presumed advantage of this is the ability to exploit different resources successively throughout ontogeny. Various taxa, however, have evolved nonfeeding, nongrowing adult stages. We show theoretically that this counterintuitive no-growth strategy is favored when the optimal larval size is greater than or equal to the optimal adult size for reproduction. We empirically investigated this in a group of parasitic worms (helminths). Helminths are transmitted trophically between hosts before reproducing in large, high-trophic-level hosts, and most undergo considerable growth as adults in their final host. Some well-studied tapeworm species (Schistocephalus, Ligula, and Digramma species) are notable exceptions; they reproduce semelparously without any growth in their final habitat (the gut of piscivorous birds). Using cross-species comparative analyses, we show that these tapeworms that do not grow in their final host (1) attain larval sizes in their last intermediate host (fishes) that are comparable to or larger than the adult sizes reached by tapeworms that do grow in the same adult niche (also piscivorous birds) and (2) are large, even as larvae, relative to the mass of their final hosts. These results are consistent with the idea that a massive larval size can make adult growth superfluous, and we discuss whether this likely applies to other complex life cycle taxa with nonfeeding, nongrowing adults. PMID:23234844

Benesh, Daniel P; Chubb, James C; Parker, Geoff A

2013-01-01

373

Changes in gas exchange characteristics during the life span of giant sequoia: implications for response to current and future concentrations of atmospheric ozone.  

PubMed

Native stands of giant sequoia (Sequoiadendron giganteum Bucholz) are being exposed to relatively high concentrations of atmospheric ozone produced in urban and agricultural areas upwind. The expected change in environmental conditions over the next 100 years is likely to be unprecedented in the life span (about 2,500 years) of giant sequoia. We determined changes in physiological responses of three age classes of giant sequoia (current-year, 12-, and 125-year-old) to differing concentrations of ozone, and assessed age-related differences in sensitivity to pollutants by examining physiological changes (gas exchange, water use efficiency) across the life span of giant sequoia (current-year, 2-, 5-, 20-, 125-, and > 2,000-year-old trees). The CO(2) exchange rate (CER) was greater in current-year (12.1 micro mol CO(2) m(-2) s(-1)) and 2-year-old seedlings (4.8 micro mol CO(2) m(-2) s(-1)) than in all older trees (3.0 micro mol CO(2) m(-2) s(-1), averaged across the four older age classes). Dark respiration was highest for current-year seedlings (-6.5 +/- 0.7 micro mol CO(2) m(-2) s(-1)) and was increased twofold in symptomatic individuals exposed to elevated ozone concentrations. Stomatal conductance (g(s)) was greater in current-year (355 mmol H(2)O m(-2) s(-1)) and 2-year-old seedlings (200 mmol H(2)O m(-2) s(-1)) than in all older trees (50 mmol H(2)O m(-2) s(-1)), indicating that the ozone concentration in substomatal cavities is higher in young seedlings than in trees. Significant changes in water use efficiency, as indicated by C(i)/C(a), occurred in trees between ages 5 and 20 years. We conclude that giant sequoias seedlings are sensitive to atmospheric ozone until they are about 5 years old. Low conductance, high water use efficiency, and compact mesophyll all contribute to a natural ozone tolerance, or defense, or both, in foliage of older trees. PMID:14967638

Grulke, N. E.; Miller, P. R.

374

Assessing the burden of sexual and reproductive ill-health: questions regarding the use of disability-adjusted life years.  

PubMed Central

The use of the disability-adjusted life year (DALY) as the unit in which to calculate the burden of disease associated with reproductive ill-health has given rise to considerable debate. Criticisms include the failure to address the problem of missing and inadequate epidemiological data, inability to deal adequately with co-morbidities, and lack of transparency in the process of ascribing disability weights to sexual and reproductive health conditions. Many of these criticisms could be addressed within the current DALY framework and a number of suggestions to do so are made. These suggestions include: (1) developing an international research strategy to determine the incidence and prevalence of reproductive ill-health and diseases, including the risk of long-term complications; (2) undertaking a research strategy using case studies, population-based surveillance data and longitudinal studies to identify, evaluate and utilize more of the existing national data sources on sexual and reproductive health; (3) comprehensively mapping the natural history of sexual and reproductive health conditions--in males and in females--and their sequelae, whether physical or psychological; (4) developing valuation instruments that are adaptable for both chronic and acute health states, that reflect a range of severity for each health state and can be modified to reflect prognosis; (5) undertaking a full review of the DALY methodology to determine what changes may be made to reduce sources of methodological and gender bias. Despite the many criticisms of the DALY as a measurement unit, it represents a major conceptual advance since it permits the combination of life expectancy and levels of dysfunction into a single measure. Measuring reproductive ill-health by counting deaths alone is inadequate for a proper understanding of the dimensions of the problem because of the young age of many of the deaths associated with reproductive ill-health and the large component of years lived with disability from many of the associated conditions.

AbouZahr, C.; Vaughan, J. P.

2000-01-01

375

Early life exposure to genistein and daidzein disrupts structural development of reproductive organs in female mice.  

PubMed

In mice, exposure to isoflavones (ISO), abundant in soy infant formula, during the first 5 d of life alters structural and functional development of reproductive organs. Effects of longer exposures are unknown. The study objective was to evaluate whether exposure to a combination of daidzein and genistein in the first 10 compared to 5 d of life results in greater adverse effects on ovarian and uterine structure in adult mice. Thirteen litters of 8-12 pups were cross-fostered and randomized to corn oil or ISO (2 mg daidzein + 5 mg genistein/kg body weight/d) for the first 5 or 10 d of life. The 10-d protocol mimicked the period when infants are fed soy protein formula (SPF) but avoids the time when suckling pups can consume mother's diet. Body and organ weights, and histology of ovaries and uteri were analyzed. There were no differences in the ovary or uterus weight, number of ovarian follicles, number of multiple oocyte follicles, or percent of ovarian cysts with 5 or 10 d ISO intervention compared to respective controls. The 10-d ISO group had higher body weights from 6 d to 4 mo of age and a higher percent of hyperplasia in the oviduct than the respective control. Lower number of ovarian corpus lutea and a higher incidence of abnormal changes were reported in the uteri of both ISO groups compared to their respective controls. Five and 10-d exposure to ISO had similar long-lasting adverse effects on the structure of ovaries and uterus in adult mice. Only the 10-d ISO exposure resulted in greater body weight gain at adulthood. PMID:22712850

Kaludjerovic, Jovana; Chen, Jianmin; Ward, Wendy E

2012-01-01

376

Life span in online communities.  

PubMed

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. PMID:21230706

Grabowski, A; Kosi?ski, R A

2010-12-06

377

Cardiovascular determinants of life span  

Microsoft Academic Search

The prevalence of cardiovascular diseases rises with aging and is one of the main causes of mortality in western countries.\\u000a In view of the progressively aging population, there is an urge for a better understanding of age-associated cardiovascular\\u000a diseases and its underlying molecular mechanisms. The risk factors for cardiovascular diseases include unhealthy diet, diabetes,\\u000a obesity, smoking, alcohol consumption, physical inactivity,

Yi Shi; Giovanni G. Camici; Thomas F. Lüscher

2010-01-01

378

Life span in online communities  

NASA Astrophysics Data System (ADS)

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.

Grabowski, A.; Kosi?ski, R. A.

2010-12-01

379

Sirt1 extends life span and delays aging in mice through the regulation of Nk2 homeobox 1 in the DMH and LH.  

PubMed

The mammalian Sir2 ortholog Sirt1 plays an important role in metabolic regulation. However, the role of Sirt1 in the regulation of aging and longevity is still controversial. Here we demonstrate that brain-specific Sirt1-overexpressing (BRASTO) transgenic mice show significant life span extension in both males and females, and aged BRASTO mice exhibit phenotypes consistent with a delay in aging. These phenotypes are mediated by enhanced neural activity specifically in the dorsomedial and lateral hypothalamic nuclei (DMH and LH, respectively), through increased orexin type 2 receptor (Ox2r) expression. We identified Nk2 homeobox 1 (Nkx2-1) as a partner of Sirt1 that upregulates Ox2r transcription and colocalizes with Sirt1 in the DMH and LH. DMH/LH-specific knockdown of Sirt1, Nkx2-1, or Ox2r and DMH-specific Sirt1 overexpression further support the role of Sirt1/Nkx2-1/Ox2r-mediated signaling for longevity-associated phenotypes. Our findings indicate the importance of DMH/LH-predominant Sirt1 activity in the regulation of aging and longevity in mammals. PMID:24011076

Satoh, Akiko; Brace, Cynthia S; Rensing, Nick; Cliften, Paul; Wozniak, David F; Herzog, Erik D; Yamada, Kelvin A; Imai, Shin-Ichiro

2013-09-01

380

Rho Kinase Inhibitor Y-27632 Prolongs the Life Span of Adult Human Keratinocytes, Enhances Skin Equivalent Development, and Facilitates Lentiviral Transduction  

PubMed Central

The use of tissue-engineered human skin equivalents (HSE) for fundamental research and industrial application requires the expansion of keratinocytes from a limited number of skin biopsies donated by adult healthy volunteers or patients. A pharmacological inhibitor of Rho-associated protein kinases, Y-27632, was recently reported to immortalize neonatal human foreskin keratinocytes. Here, we investigated the potential use of Y-27632 to expand human adult keratinocytes and evaluated its effects on HSE development and in vitro gene delivery assays. Y-27632 was found to significantly increase the life span of human adult keratinocytes (up to five to eight passages). The epidermal morphology of HSEs generated from high-passage, Y-27632-treated keratinocytes resembled the native epidermis and was improved by supplementing Y-27632 during the submerged phase of HSE development. In addition, Y-27632-treated keratinocytes responded normally to inflammatory stimuli, and could be used to generate HSEs with a psoriatic phenotype, upon stimulation with relevant cytokines. Furthermore, Y-27632 significantly enhanced both lentiviral transduction efficiency of primary adult keratinocytes and epidermal morphology of HSEs generated thereof. Our study indicates that Y-27632 is a potentially powerful tool that is used for a variety of applications of adult human keratinocytes.

Rodijk-Olthuis, Diana; Jansen, Patrick A.M.; van Vlijmen-Willems, Ivonne M.J.J.; van Erp, Piet E.; Joosten, Irma; Zeeuwen, Patrick L.J.M.

2012-01-01

381

Human Keratinocytes That Express hTERT and Also Bypass a p16INK4a-Enforced Mechanism That Limits Life Span Become Immortal yet Retain Normal Growth and Differentiation Characteristics  

Microsoft Academic Search

Normal human cells exhibit a limited replicative life span in culture, eventually arresting growth by a process termed senescence. Progressive telomere shortening appears to trigger senescence in normal human fibroblasts and retinal pigment epithelial cells, as ectopic expression of the telomerase catalytic subunit, hTERT, immortalizes these cell types directly. Telomerase expression alone is insufficient to enable certain other cell types

MARK A. DICKSON; WILLIAM C. HAHN; YASUSHI INO; VINCENT RONFARD; JENNY Y. WU; ROBERT A. WEINBERG; DAVID N. LOUIS; FREDERICK P. LI; JAMES G. RHEINWALD

2000-01-01

382

Towards a general life-history model of the superorganism: predicting the survival, growth and reproduction of ant societies.  

PubMed

Social insect societies dominate many terrestrial ecosystems across the planet. Colony members cooperate to capture and use resources to maximize survival and reproduction. Yet, when compared with solitary organisms, we understand relatively little about the factors responsible for differences in the rates of survival, growth and reproduction among colonies. To explain these differences, we present a mathematical model that predicts these three rates for ant colonies based on the body sizes and metabolic rates of colony members. Specifically, the model predicts that smaller colonies tend to use more energy per gram of biomass, live faster and die younger. Model predictions are supported with data from whole colonies for a diversity of species, with much of the variation in colony-level life history explained based on physiological traits of individual ants. The theory and data presented here provide a first step towards a more general theory of colony life history that applies across species and environments. PMID:22896271

Shik, Jonathan Z; Hou, Chen; Kay, Adam; Kaspari, Michael; Gillooly, James F

2012-08-15

383

A Life History Trade-Off Between Flight Ability and Reproductive Behavior in Male Field Crickets ( Gryllus texensis )  

Microsoft Academic Search

Male field crickets (Gryllus texensis) that differ in flight ability incur a life history trade-off between flight ability and reproduction, where flight ability\\u000a comes with a male fitness cost. In courtship trials, flight-capable males produced courtship song, a necessary signal for\\u000a mating success, with a significantly lower probability than flight-incapable males. The trade-off was evident in young males,\\u000a and a

Patrick A. Guerra; Gerald S. Pollack

2007-01-01

384

BDNF transcripts, proBDNF and proNGF, in the cortex and hippocampus throughout the life span of the rat.  

PubMed

Neurotrophins are established molecular mediators of neuronal plasticity in the adult brain. We analyzed the impact of aging on brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) protein isoforms, their receptors, and on the expression patterns of multiple 5' exon-specific BDNF transcripts in the rat cortex and hippocampus throughout the life span of the rat (6, 12, 18, and 24 months of age). ProNGF was increased during aging in both structures. Mature NGF gradually decreased in the cortex, and, in 24-month-old animals, it was 30 % lower than that in adult 6-month-old rats. The BDNF expression did not change during aging, while proBDNF accumulated in the hippocampus of aged rats. Hippocampal total BDNF mRNA was lower in 12-month-old animals, mostly as a result of a decrease of BDNF transcripts 1 and 2. In contrast to the region-specific regulation of specific exon-containing BDNF mRNAs in adult animals, the same BDNF RNA isoforms (containing exons III, IV, or VI) were present in both brain structures of aged animals. Deficits in neurotrophin signaling were supported by the observed decrease in Trk receptor expression which was accompanied by lower levels of the two main downstream effector kinases, pAkt and protein kinase C. The proteolytic processing of p75NTR observed in 12-month-old rats points to an additional regulatory mechanism in early aging. The changes described herein could contribute to reduced brain plasticity underlying the age-dependent decline in cognitive function. PMID:23255148

Perovic, Milka; Tesic, Vesna; Mladenovic Djordjevic, Aleksandra; Smiljanic, Kosara; Loncarevic-Vasiljkovic, Natasa; Ruzdijic, Sabera; Kanazir, Selma

2012-12-21

385

Recruitment and Retention Strategies for Minority or Poor Clinical Research Participants: Lessons From the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study  

PubMed Central

Purpose of the study:?Investigating health disparities requires studies designed to recruit and retain racially and socioeconomically diverse cohorts. It is critical to address the barriers that disproportionately affect participation in clinical research by minorities and the socioeconomically disadvantaged. This study sought to identify and rectify these barriers to recruit and retain a biracial (African American and non-Hispanic White) and socioeconomically diverse cohort for a longitudinal study.?Design and Method:?The Healthy Aging in Neighborhoods of Diversity across the Life Span study is a 20-year longitudinal examination of how race and socioeconomic status influence the development of age-related health disparities. One goal was to create a multifactorial recruitment and retention strategy. The recruitment paradigm targeted known barriers and identified those unique to the study's urban environment. The retention paradigm mirrored the recruitment plan but was based on specifically developed approaches.?Results:?This cohort recruitment required attention to developing community partnerships, designing the research study to meet the study hypotheses and to provide benefit to participants, providing a safe community-based site for the research and creating didactics to develop staff cultural proficiency. These efforts facilitated study implementation and enhanced recruitment resulting in accrual of a biracial and socioeconomically diverse cohort of 3,722 participants.?Implications:?Recruiting and retaining minority or poor research participants is challenging but possible. The essential facets include clear communication of the research hypothesis, focus on providing a direct benefit for participants, and selection of a hypothesis that is directly relevant to the community studied

Ejiogu, Ngozi; Norbeck, Jennifer H.; Mason, Marc A.; Cromwell, Bridget C.; Zonderman, Alan B.; Evans, Michele K.

2011-01-01

386

Correlations of life-span variation parameters in 128 successive generations of Drosophila melanogaster with changes in atmospheric pressure and geomagnetic activity  

NASA Astrophysics Data System (ADS)

Correlations between the parameters of life-span (LS) distribution of Drosophila melanogaster, including mean LS (MLS) and the time of 10 and 90% population mortality, and some geophysical parameters that are usually beyond the control of researchers dealing with laboratory cultures, including atmospheric pressure, solar activity indices (Wolf’s sunspot numbers and 2,800-MHz radio flux), and geomagnetic activity (planetary index, Kp), were studied. Geophysical data were obtained from free-access official web sites of the National Oceanic & Atmospheric Administration of the US Department of Commerce and the Institute of Terrestrial Magnetism and Radiowave Propagation of the Russian Academy of Sciences. The geophysical parameters were calculated only for the period corresponding to 10 days of preimaginal development of the flies from egg to imago. Canonical correlation analysis, calculation of the non-parametric Spearman rank-order correlation coefficients, and graphical data analysis were used. Highly significant correlations between parameters of LS distribution in males and females and environmental factors, such as the atmospheric pressure on the 4th and 5th day of development and geomagnetic activity indices (Kp) on the 6th and 10th day of development were found, with correlation coefficients varying from 0.31 to 0.37 (P<0.02). Assuming a causal relationship between geophysical factors and LS, it may be hypothesized that energetically weak environmental factors determine the formation of LS oscillatory dynamics in laboratory populations. The possible mechanisms underlying the contribution of these environmental factors to the LS variation in successive generations are discussed.

Izmaylov, D. M.; Obukhova, L. K.; Konradov, A. A.

2005-05-01

387

INFLUENCE OF THE ORGANOPHOSPHATE INSECTICIDE FENTHION ON 'MYSIDOPSIS BAHIA' EXPOSED DURING A COMPLETE LIFE CYCLE: 1. SURVIVAL, REPRODUCTION, AND AGE-SPECIFIC GROWTH  

EPA Science Inventory

Survival, growth, and various measures of reproductive performance were examined for an estuarine mysid, Mysidopsis bahia, throughout its life cycle during exposure to the organophosphate insecticide, fenthion. Both individual fecundity of females and total population production ...

388

Life history plasticity after attaining a dietary threshold for reproduction is associated with protein storage in flesh flies  

PubMed Central

Summary Body condition affects the timing and magnitude of life history transitions. Therefore, identifying proximate mechanisms involved in assessing condition is critical to understanding how these mechanisms affect the expression of life history plasticity. Nutrient storage is an important body condition parameter, likely playing roles in both attaining minimum body-condition thresholds for life history transitions and expression of life history traits. We manipulated protein availability for females of the flesh fly Sarcophaga crassipalpis to determine whether reproductive timing and output would remain plastic or become fixed. Liver was provided for 0, 2, 4, or 6 days of adult pre-reproductive development. Significantly, liver was removed after the feeding threshold had been attained and females had committed to producing a clutch. We also identified the major storage proteins and monitored their abundances, because protein stores may serve as an index of body condition and therefore may play an important role in life history transitions and plasticity. Flesh flies showed clear post-threshold plasticity in reproductive timing. Females fed protein for 2 days took ~30% longer to provision their clutch than those fed for 4 or 6 days. Observations of oogenesis showed the 2-day group expressed a different developmental program including slower egg provisioning. Protein availability also affected reproductive output. Females fed protein for 2 days produced ~20% fewer eggs than females fed 4 or 6 days. Six-day treated females provisioned larger eggs than 4-day treated females, followed by 2-day treated females with the smallest eggs. Two storage proteins were identified, LSP-1 and LSP-2. LSP-2 accumulation differed across feeding treatments. The 2- and 4-day treatment groups accumulated LSP-2 stores but depleted them during provisioning of the first clutch, whereas the 6-day group accumulated the greatest quantity of LSP-2 and had substantial LSP-2 stores remaining at the end of the clutch. This pattern of accumulation and depletion suggests that LSP-2 could play roles in both provisioning the current clutch and future clutches, making it a good candidate molecule for affecting reproductive timing and allotment. LSP-1 was not associated with post-threshold plasticity; it was carried over from larval feeding into adulthood and depleted uniformly across all feeding groups.

Hahn, Daniel A.; James, Laura N.; Milne, Kathy R.; Hatle, John D.

2009-01-01

389

Reproduction and Early Life History of the Redfin Pickerel, (Esox americanus americanus).  

National Technical Information Service (NTIS)

The reproductive strategy of the redf in pickerel (Esox americanus americanus) in a blackwater system in Sumter County, South Carolina was studied using daily aging techniques derived from otolith analysis. The presence of biannual spawning, a significant...

M. S. Ballek

1994-01-01

390

Developmental exposure to endocrine-disrupting chemicals programs for reproductive tract alterations and obesity later in life1234  

PubMed Central

Many chemicals in the environment, especially those with estrogenic activity, are able to disrupt the programming of endocrine signaling pathways established during development; these chemicals are referred to as endocrine-disrupting chemicals. Altered programming can result in numerous adverse consequences in estrogen-target tissues, some of which may not be apparent until later in life. For example, a wide variety of structural, functional, and cellular effects have been identified in reproductive tract tissues. In addition to well-documented reproductive changes, obesity and diabetes have joined the list of adverse effects that have been associated with developmental exposure to environmental estrogens and other endocrine-disrupting chemicals. Obesity is a significant public health problem reaching epidemic proportions worldwide. Experimental animal studies document an association of developmental exposure to environmental estrogens and obesity. For example, a murine model of perinatal exposure to diethylstilbestrol has proven useful in studying mechanisms involved in abnormal programming of differentiating estrogen-target tissues, including reproductive tract tissues and adipocytes. Other environmental estrogens, including the environmental contaminant bisphenol A, have also been linked to reproductive problems and obesity later in life. Epidemiology studies support similar findings in humans, as do studies of cells in culture. Together, these findings suggest new targets for abnormal programming by estrogenic chemicals and provide evidence supporting the scientific concept termed the developmental origins of adult disease. Furthermore, the association of environmental estrogens with obesity and diabetes expands the focus on these diseases from intervention or treatment to include prevention or avoidance of chemical modifiers, especially during critical windows of development.

2011-01-01

391

Developmental exposure to endocrine-disrupting chemicals programs for reproductive tract alterations and obesity later in life.  

PubMed

Many chemicals in the environment, especially those with estrogenic activity, are able to disrupt the programming of endocrine signaling pathways established during development; these chemicals are referred to as endocrine-disrupting chemicals. Altered programming can result in numerous adverse consequences in estrogen-target tissues, some of which may not be apparent until later in life. For example, a wide variety of structural, functional, and cellular effects have been identified in reproductive tract tissues. In addition to well-documented reproductive changes, obesity and diabetes have joined the list of adverse effects that have been associated with developmental exposure to environmental estrogens and other endocrine-disrupting chemicals. Obesity is a significant public health problem reaching epidemic proportions worldwide. Experimental animal studies document an association of developmental exposure to environmental estrogens and obesity. For example, a murine model of perinatal exposure to diethylstilbestrol has proven useful in studying mechanisms involved in abnormal programming of differentiating estrogen-target tissues, including reproductive tract tissues and adipocytes. Other environmental estrogens, including the environmental contaminant bisphenol A, have also been linked to reproductive problems and obesity later in life. Epidemiology studies support similar findings in humans, as do studies of cells in culture. Together, these findings suggest new targets for abnormal programming by estrogenic chemicals and provide evidence supporting the scientific concept termed the developmental origins of adult disease. Furthermore, the association of environmental estrogens with obesity and diabetes expands the focus on these diseases from intervention or treatment to include prevention or avoidance of chemical modifiers, especially during critical windows of development. PMID:22089436

Newbold, Retha R

2011-11-16

392

Seasonal trends in Ceratitis capitata reproductive potential derived from live-caught females in Greece  

PubMed Central

Reproductive data of individual insects are extremely hard to collect under natural conditions, thus the study of research questions related to oviposition has not advanced. Patterns of oviposition are often inferred only indirectly, through monitoring of host infestation, whereas the influence of age structure and several other factors on oviposition remains unknown. Using a new approach, in this article, we live-trapped wild Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) females on the Greek island of Chios during two field seasons. For their remaining lifetime, these females were placed individually in small cages and their daily oviposition was monitored. Reproduction rates between cohorts from different collection dates were then compared. The results showed that in the different captive cohorts the average remaining lifetime and reproduction were highly variable within and between seasons. Multivariate regression analysis showed that the month of capture had a significant effect on captive life span, average daily reproduction, and patterns of egg laying. The effect of year was significant on reproduction, but not on captive life span. These differences between sampling periods probably reflect differences in the availability of hosts and other factors that vary during the season and affect age structure and reproduction. Using a non-parametric generalized additive model, we found a statistically significant correlation between the captive life span and the average daily reproduction. These findings and the experimental approach have several important implications.

Kouloussis, Nikos A.; Papadopoulos, Nikos T.; Katsoyannos, Byron I.; Muller, Hans-Georg; Wang, Jane-Ling; Su, Yu-Ru; Molleman, Freerk; Carey, James R.

2012-01-01

393

Evolutionary relationships among food habit, loss of flight, and reproductive traits: life-history evolution in the Silphinae (Coleoptera: Silphidae).  

PubMed

Flightlessness in insects is generally thought to have evolved due to changes in habitat environment or habitat isolation. Loss of flight may have changed reproductive traits in insects, but very few attempts have been made to assess evolutionary relationships between flight and reproductive traits in a group of related species. We elucidated the evolutionary history of flight loss and its relationship to evolution in food habit, relative reproductive investment, and egg size in the Silphinae (Coleoptera: Silphidae). Most flight-capable species in this group feed primarily on vertebrate carcasses, whereas flightless or flight-dimorphic species feed primarily on soil invertebrates. Ancestral state reconstruction based on our newly constructed molecular phylogenetic tree implied that flight muscle degeneration occurred twice in association with food habit changes from necrophagy to predatory, suggesting that flight loss could evolve independently from changes in the environmental circumstances per se. We found that total egg production increased with flight loss. We also found that egg size increased with decreased egg number following food habit changes in the lineage leading to predaceous species, suggesting that selection for larger larvae intensified with the food habit change. This correlated evolution has shaped diverse life-history patterns among extant species of Silphinae. PMID:18507741

Ikeda, Hiroshi; Kagaya, Takashi; Kubota, Kohei; Abe, Toshio

2008-05-27

394

Acute leukemia during reproductive life: its course, complications, and sequelae for fertility  

Microsoft Academic Search

Acute leukemia is less common during the reproductive years than in children or in postmenopausal women. Effective chemotherapy exists for adult lymphocytic leukemia, and the median survival is 18 to 20 months. Acute myelogenous leukemia still has a less favorable prognosis, with a medial survival of 12 months despite effective chemotherapeutic agents. The occurrence of acute leukemia in pregnancy does

J. D. Bitran; D. G. Roth

1976-01-01

395

Influence of early-life nutrition on mortality and reproductive success during a subsequent famine in a preindustrial population  

PubMed Central

Individuals with insufficient nutrition during development often experience poorer later-life health and evolutionary fitness. The Predictive Adaptive Response (PAR) hypothesis proposes that poor early-life nutrition induces physiological changes that maximize fitness in similar environments in adulthood and that metabolic diseases result when individuals experiencing poor nutrition during development subsequently encounter good nutrition in adulthood. However, although cohort studies have shown that famine exposure in utero reduces health in favorable later-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition, leaving the evolutionary origins of such plasticity unexplored. Taking advantage of a well-documented famine and unique datasets of individual life histories and crop yields from two preindustrial Finnish populations, we provide a test of key predictions of the PAR hypothesis. Known individuals from fifty cohorts were followed from birth until the famine, where we analyzed their survival and reproductive success in relation to the crop yields around birth. We were also able to test whether the long-term effects of early-life nutrition differed between individuals of varying socioeconomic status. We found that, contrary to predictions of the PAR hypothesis, individuals experiencing low early-life crop yields showed lower survival and fertility during the famine than individuals experiencing high early-life crop yields. These effects were more pronounced among young individuals and those of low socioeconomic status. Our results do not support the hypothesis that PARs should have been favored by natural selection and suggest that alternative models may need to be invoked to explain the epidemiology of metabolic diseases.

Hayward, Adam D.; Rickard, Ian J.; Lummaa, Virpi

2013-01-01

396

Influence of early-life nutrition on mortality and reproductive success during a subsequent famine in a preindustrial population.  

PubMed

Individuals with insufficient nutrition during development often experience poorer later-life health and evolutionary fitness. The Predictive Adaptive Response (PAR) hypothesis proposes that poor early-life nutrition induces physiological changes that maximize fitness in similar environments in adulthood and that metabolic diseases result when individuals experiencing poor nutrition during development subsequently encounter good nutrition in adulthood. However, although cohort studies have shown that famine exposure in utero reduces health in favorable later-life conditions, no study on humans has demonstrated the predicted fitness benefit under low later-life nutrition, leaving the evolutionary origins of such plasticity unexplored. Taking advantage of a well-documented famine and unique datasets of individual life histories and crop yields from two preindustrial Finnish populations, we provide a test of key predictions of the PAR hypothesis. Known individuals from fifty cohorts were followed from birth until the famine, where we analyzed their survival and reproductive success in relation to the crop yields around birth. We were also able to test whether the long-term effects of early-life nutrition differed between individuals of varying socioeconomic status. We found that, contrary to predictions of the PAR hypothesis, individuals experiencing low early-life crop yields showed lower survival and fertility during the famine than individuals experiencing high early-life crop yields. These effects were more pronounced among young individuals and those of low socioeconomic status. Our results do not support the hypothesis that PARs should have been favored by natural selection and suggest that alternative models may need to be invoked to explain the epidemiology of metabolic diseases. PMID:23918366

Hayward, Adam D; Rickard, Ian J; Lummaa, Virpi

2013-08-05

397

An FXPRLamide Neuropeptide Induces Seasonal Reproductive Polyphenism Underlying a Life-History Tradeoff in the Tussock Moth  

PubMed Central

The white spotted tussock moth, Orgyia thyellina, is a typical insect that exhibits seasonal polyphenisms in morphological, physiological, and behavioral traits, including a life-history tradeoff known as oogenesis-flight syndrome. However, the developmental processes and molecular mechanisms that mediate developmental plasticity, including life-history tradeoff, remain largely unknown. To analyze the molecular mechanisms involved in reproductive polyphenism, including the diapause induction, we first cloned and characterized the diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN) cDNA encoding the five Phe-X-Pro-Arg-Leu-NH2 (FXPRLa) neuropeptides: DH, PBAN, and ?-, ?-, and ?-SGNPs (subesophageal ganglion neuropeptides). This gene is expressed in neurosecretory cells within the subesophageal ganglion whose axonal projections reach the neurohemal organ, the corpus cardiacum, suggesting that the DH neuroendocrine system is conserved in Lepidoptera. By injection of chemically synthetic DH and anti-FXPRLa antibody into female pupae, we revealed that not only does the Orgyia DH induce embryonic diapause, but also that this neuropeptide induces seasonal polyphenism, participating in the hypertrophy of follicles and ovaries. In addition, the other four FXPRLa also induced embryonic diapause in O. thyellina, but not in Bombyx mori. This is the first study showing that a neuropeptide has a pleiotropic effect in seasonal reproductive polyphenism to accomplish seasonal adaptation. We also show that a novel factor (i.e., the DH neuropeptide) acts as an important inducer of seasonal polyphenism underlying a life-history tradeoff. Furthermore, we speculate that there must be evolutionary conservation and diversification in the neuroendocrine systems of two lepidopteran genera, Orgyia and Bombyx, in order to facilitate the evolution of coregulated life-history traits and tradeoffs.

Uehara, Hiroshi; Senoh, Yukiko; Yoneda, Kyohei; Kato, Yoshiomi; Shiomi, Kunihiro

2011-01-01

398

Reproductive seasonality in captive wild ruminants: implications for biogeographical adaptation, photoperiodic control, and life history.  

PubMed

Many ruminant species show seasonal patterns of reproduction. Causes for this are widely debated, and include adaptations to seasonal availability of resources (with cues either from body condition in more tropical, or from photoperiodism in higher latitude habitats) and/or defence strategies against predators. Conclusions so far are limited to datasets with less than 30 species. Here, we use a dataset on 110 wild ruminant species kept in captivity in temperate-zone zoos to describe their reproductive patterns quantitatively [determining the birth peak breadth (BPB) as the number of days in which 80% of all births occur]; then we link this pattern to various biological characteristics [latitude of origin, mother-young-relationship (hider/follower), proportion of grass in the natural diet (grazer/browser), sexual size dimorphism/mating system], and compare it with reports for free-ranging animals. When comparing taxonomic subgroups, variance in BPB is highly correlated to the minimum, but not the maximum BPB, suggesting that a high BPB (i.e. an aseasonal reproductive pattern) is the plesiomorphic character in ruminants. Globally, latitude of natural origin is highly correlated to the BPB observed in captivity, supporting an overruling impact of photoperiodism on ruminant reproduction. Feeding type has no additional influence; the hider/follower dichotomy, associated with the anti-predator strategy of 'swamping', has additional influence in the subset of African species only. Sexual size dimorphism and mating system are marginally associated with the BPB, potentially indicating a facilitation of polygamy under seasonal conditions. The difference in the calculated Julian date of conception between captive populations and that reported for free-ranging ones corresponds to the one expected if absolute day length was the main trigger in highly seasonal species: calculated day length at the time of conception between free-ranging and captive populations followed a y = x relationship. Only 11 species (all originating from lower latitudes) were considered to change their reproductive pattern distinctively between the wild and captivity, with 10 becoming less seasonal (but not aseasonal) in human care, indicating that seasonality observed in the wild was partly resource-associated. Only one species (Antidorcas marsupialis) became more seasonal in captivity, presumably because resource availability in the wild overrules the innate photoperiodic response. Reproductive seasonality explains additional variance in the body mass-gestation period relationship, with more seasonal species having shorter gestation periods for their body size. We conclude that photoperiodism, and in particular absolute day length, are genetically fixed triggers for reproduction that may be malleable to some extent by body condition, and that plasticity in gestation length is an important facilitator that may partly explain the success of ruminant radiation to high latitudes. Evidence for an anti-predator strategy involving seasonal reproduction is limited to African species. Reproductive seasonality following rainfall patterns may not be an adaptation to give birth in periods of high resource availability but an adaptation to allow conception only at times of good body condition. PMID:22780447

Zerbe, Philipp; Clauss, Marcus; Codron, Daryl; Bingaman Lackey, Laurie; Rensch, Eberhard; Streich, Jürgen W; Hatt, Jean-Michel; Müller, Dennis W H

2012-07-10

399

The Effect of Family Planning Methods Used by Women of Reproductive Age on Their Sexual Life  

Microsoft Academic Search

The family planning (FP) methods used by women of reproductive age can have negative or positive influences on the sex lives\\u000a of couples. Couples should be aware of the effects of the FP method they use on their sex lives to be able to improve the\\u000a quality. This descriptive study was carried out to determine the effects of contraceptive methods

Ebru Gabalci; Fusun Terzioglu

2010-01-01

400

Effects of temperature and salinity on prereproductive life span and reproductive traits of two species of Artemia (Branchiopoda, Anostraca) from Argentina: Artemia franciscana and A. persimilis  

Microsoft Academic Search

The identification of the environmental conditions inducing different ecophysiological responses in the different strains\\u000a and populations of the brine shrimp Artemia should improve the understanding of their biogeographic distribution. Nauplii from two Argentinean brine shrimp populations,\\u000a Artemia persimilis from Salinas Grandes de Hidalgo (province of La Pampa) and Artemia franciscana from Laguna Mar Chiquita (province of Cordoba), were grown up

G. R. Medina; J. Goenaga; F. Hontoria; G. Cohen; F. Amat

2007-01-01

401

6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY ...  

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

6. DETAIL OF VERTICAL LIFT SPAN AND FIXED SPAN IMMEDIATELY NORTH OF VERTICAL LIFT SPAN, LOOKING SOUTHEAST. - Shippingsport Bridge, Spanning Illinois River at State Route 51, La Salle, La Salle County, IL

402

Cost of reproduction, resource quality, and terminal investment in a burying beetle.  

PubMed

We evaluate the cost-of-reproduction hypothesis in the burying beetle Nicrophorus orbicollis and examine how the importance of this trade-off changes as females age (i.e., the terminal-investment hypothesis). These beetles breed on small vertebrate carcasses, which serve as a food resource for them and their offspring. Consistent with the cost-of-reproduction hypothesis, females manipulated to overproduce offspring suffered a reduction in fecundity and life span when compared to controls, although all reproducing females had reduced life spans compared to nonbreeding females. Older females produced larger broods and allocated less of the carcass to their own body mass and a greater proportion to offspring than did younger females. Resource allocation to offspring increased with age. Females given larger carcasses invested more in current reproduction and less in future reproduction than did females given smaller carcasses. Our results provide unconfounded support for both the cost-of-reproduction hypothesis (i.e., current reproduction constrains future reproductive output) and the terminal-investment hypothesis (i.e., the importance of the trade-off between current and future reproduction declines with age such that allocation to current reproduction should increase as females age). PMID:19775240

Creighton, J Curtis; Heflin, Nicholas D; Belk, Mark C

2009-11-01

403

Life expectancy, economic inequality, homicide, and reproductive timing in Chicago neighbourhoods.  

PubMed Central

In comparisons among Chicago neighbourhoods, homicide rates in 1988-93 varied more than 100-fold, while male life expectancy at birth ranged from 54 to 77 years, even with effects of homicide mortality removed. This "cause deleted" life expectancy was highly correlated with homicide rates; a measure of economic inequality added significant additional prediction, whereas median household income did not. Deaths from internal causes (diseases) show similar age patterns, despite different absolute levels, in the best and worst neighbourhoods, whereas deaths from external causes (homicide, accident, suicide) do not. As life expectancy declines across neighbourhoods, women reproduce earlier; by age 30, however, neighbourhood no longer affects age specific fertility. These results support the hypothesis that life expectancy itself may be a psychologically salient determinant of risk taking and the timing of life transitions.

Wilson, M.; Daly, M.

1997-01-01

404

Prenatal Exposure to Bisphenol A at Environmentally Relevant Doses Adversely Affects the Murine Female Reproductive Tract Later in Life  

PubMed Central

Background Exposure to endocrine-disrupting chemicals during critical developmental periods causes adverse consequences later in life; an example is prenatal exposure to the pharmaceutical diethylstilbestrol (DES). Bisphenol A (BPA), an environmental estrogen used in the synthesis of plastics, is of concern because its chemical structure resembles that of DES, and it is a “high-volume production” chemical with widespread human exposure. Objectives In this study we investigated whether prenatal BPA causes long-term adverse effects in female reproductive tissues in an experimental animal model previously shown useful in studying effects of prenatal DES. Methods Timed pregnant CD-1 mice were treated on days 9–16 of gestation with BPA (0.1, 1, 10, 100, or 1,000 ?g/kg/day). After delivery, pups were held for 18 months; reproductive tissues were then evaluated. Results Ovarian cysts were significantly increased in the 1-?g/kg BPA group; ovarian cyst-adenomas were seen in the other three BPA-treated groups but not in corn-oil controls. We observed increased progressive proliferative lesions of the oviduct after BPA treatment, similar to those described in response to DES. Further, although not statistically different from the controls, prominent mesonephric (Wolffian) remnants and squamous metaplasia of the uterus, as well as vaginal adenosis, were present in BPA-treated mice, similar to lesions reported following DES treatment. More severe pathologies observed in some BPA-treated animals included atypical hyperplasia and stromal polyps of the uterus; sarcoma of the uterine cervix; and mammary adenocarcinoma. We did not observe these lesions in controls. Conclusions These data suggest that BPA causes long-term adverse reproductive and carcinogenic effects if exposure occurs during critical periods of differentiation.

Newbold, Retha R.; Jefferson, Wendy N.; Padilla-Banks, Elizabeth

2009-01-01

405

Covariation in life-history traits: differential effects of diet on condition, hormones, behavior, and reproduction in genetic finch morphs.  

PubMed

The relative contribution of genetic and environmental factors in determining variation in life-history traits is of central interest to evolutionary biologists, but the physiological mechanisms underlying these traits are still poorly understood. Here we experimentally demonstrate opposing effects of nutritional stress on immune function, endocrine physiology, parental care, and reproduction between red and black head-color morphs of the Gouldian finch (Erythrura gouldiae). Although the body condition of black morphs was largely unaffected by diet manipulation, red birds were highly sensitive to dietary changes, exhibiting considerable within-individual changes in condition and immune function. Consequently, nutritionally stressed red birds delayed breeding, produced smaller broods, and reared fewer and lower-quality foster offspring than black morphs. Differences in offspring quality were largely due to morph-specific differences in parental effort: red morphs reduced parental provisioning, whereas black morphs adaptively elevated their provisioning effort to meet the increased nutritional demands of their foster brood. Nutritionally stressed genetic morphs also exhibited divergent glucocorticoid responses. Black morphs showed reduced corticosterone-binding globulin (CBG) concentrations and increased levels of free corticosterone, whereas red morphs exhibited reduced free corticosterone levels and elevated CBG concentrations. These opposing glucocorticoid responses highlight intrinsic differences in endocrine sensitivities and plasticity between genetic morphs, which may underlie the morph-specific differences in condition, behavior, and reproduction and thus ultimately contribute to the evolution and maintenance of color polymorphism. PMID:22322225

Pryke, Sarah R; Astheimer, Lee B; Griffith, Simon C; Buttemer, William A

2012-01-27

406

Bioscience-bioethics and life factors affecting reproduction with special reference to the Indigenous Australian population.  

PubMed

The demand for equality of recognition or respect is the dominant passion of modernity. The 20th century experienced a giant leap in technological inventiveness and ruthless use of technological power. In the 21st century, human welfare and environmental wellbeing demand fundamental political appraisal. We have the means, if we choose, to eradicate poverty and to responsibly protect the global environment. However, economic, political and cultural systems act to differentially allocate the benefits and risks for growth between socioeconomic groups. For example, it is a matter of pride that the neonatal mortality rate in affluent societies has dropped substantially since the late 1970s. However, the level of infant mortality (three times the national average) and low birthweight (13%) among the Indigenous Australian population is the highest in the country. With hindsight we now know that is the inevitable legacy of Australia's colonial history. Chronic physical and psychological stress is recognized as an important etiological factor in many lifestyle diseases of the cardiovascular, immune and reproductive systems. Diseases of adaptation are further advanced by non-adaptive lifestyle choices, depression, alcoholism and other drug dependencies. This review describes the principles of bioscience ethics and targets equity issues as they affect human reproduction across generations with particular reference to the Indigenous population of Australia. The review also considers ways we may advance global and cultural maturity from the Indigenous Australian perspective and proposes an ecologically based model of preventative care. If we are to embrace fundamental social change and protect future children without threatening parents' basic freedoms, then new beliefs and priorities--based on a compassionate understanding of biological systems--must evolve from the general public. Belief in human rights arising from a sense of human dignity is a collective outcome originating from individual commitment. The golden rule; that is, Nature's principle of reciprocity, is fundamental in bridging the gap between knowledge and effective action. PMID:15798014

Pollard, Irina

2005-04-01

407

The structure of a thermophilic archaeal virus shows a dsDNA viral capsid type that spans all domains of life  

SciTech Connect

Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth >80°C) at the base of the universal tree of life, suggesting that thermophiles were among the first forms of life on earth. Very few viruses have been identified from Archaea as compared to Bacteria and Eukarya. We report here the structure of a hyperthermophilic virus isolated from an archaeal host found in hot springs in Yellowstone National Park. The sequence of the circular double-stranded DNA viral genome shows that it shares little similarity to other known genes in viruses or other organisms. By comparing the tertiary and quaternary structures of the coat protein of this virus with those of a bacterial and an animal virus, we find conformational relationships among all three, suggesting that some viruses may have a common ancestor that precedes the division into three domains of life >3 billion years ago.

G. Rice; L. Tang; K. Stedman; F. Roberto; J. Spuhler; E. Gillitzer; J. E. Johnson; T. Douglas; M. Young

2004-05-01

408

End-of-life decision making regarding infants of artificial reproductive techniques and spontaneous conception  

Microsoft Academic Search

Objective: Our goal was to determine if differences exist in the decisions made regarding dying infants based on method of conception. No studies have examined end-of-life decisions for infants regarding method of conception. Study design: We reviewed the charts of infants who were born and died in our institution between January 1, 2001 through December 31, 2005. Method of conception,

Bridget A. Hempel; Ian R. Holzman

2008-01-01

409

On the Life History of Planktonic Foraminifera: Lunar Reproduction Cycle in Globigerinoides Sacculifer (Brady)  

Microsoft Academic Search

Detailed plankton sampling in the Gulf of Elat, Red Sea, demonstrates a lunar periodicity in the abundance of the foraminifer Globigerinoides sacculifer in surface water as well as below the photic zone. Shell size distribution coupled with abundance changes and laboratory observations suggests the following scheme for the life cycle of this spinose foraminifer: Young individuals of roughly 200 µm

Jonathan Erez; Ahuva Almogi-Labin; Sophie Avraham

1991-01-01

410

Bridge Types: Suspension Bridge Spans, Section AA; Cantilever Truss Spans, ...  

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

Bridge Types: Suspension Bridge Spans, Section A-A; Cantilever Truss Spans, Section B-B; Through Truss Spans, Section C-C; Deck Truss Spans, Section D-D - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

411

Population dynamics of noncytoplasmic incompatibility-inducing Wolbachia in Nilaparvata lugens and its effects on host adult life span and female fitness.  

PubMed

Wolbachia are bacteria that live intracellularly in a wide variety of arthropods. They are maternally inherited and can affect both reproduction and fitness of its host. When infected males mate with uninfected females or females infected by a different Wolbachia strain, there is often a failure of karyogamy, which is usually attributed to cytoplasmic incompatibility (CI). We measured the strength of CI induced by Wolbachia and the fitness effects in three Chinese populations of the brown planthopper Nilaparvata lugens from Hainan, Yunnan, and Guangxi provinces, respectively. No evidence for CI was found in any of the populations, whereas an enhanced fecundity and shortened longevity were observed only in the Hainan population. The infection density was significantly higher in the Hainan population than in the Guangxi population. The Wolbachia strain infecting the three populations appeared to be the same based on the nucleotide sequence of the wsp gene. Therefore, the variable effects of Wolbachia on host fitness seem to be the result of differences in the host genetic background and Wolbachia infection density. The ability of the non-CI-inducing Wolbachia to maintain themselves in their hosts may be attributed to their positive effects on host fecundity and efficient maternal transmission. PMID:22182545

Zhang, Hui; Zhang, Kai-Jun; Hong, Xiao-Yue

2010-12-01

412

Structural and polypeptide differences between envelopes of infective and reproductive life cycle forms of Chlamydia spp.  

PubMed Central

Significant differences in cysteine-containing proteins and detergent-related solubility properties were observed between outer membrane protein complexes of reproductive (reticulate body) and infective (elementary body) forms of Chlamydia psittaci (6BC). Elementary bodies harvested at 48 h postinfection possessed a 40-kilodalton major outer membrane protein and three extraordinarily cysteine-rich outer membrane proteins of 62, 59, and 12 kilodaltons, all of which were not solubilized by sodium dodecyl sulfate in the absence of thiol reagents. Intracellularly dividing reticulate bodies harvested at 21 h postinfection were severely deficient in the cysteine-rich proteins but possessed almost as much major outer membrane protein as did the elementary bodies. Most of the major outer membrane protein of reticulate bodies was solubilized by sodium dodecyl sulfate and was present in envelopes as monomers, although a proportion formed disulfide-cross-linked oligomers. By 21 to 24 h postinfection, reticulate bodies commenced synthesis of the cysteine-rich proteins which were found in outer membranes as disulfide-cross-linked complexes. The outer membranes of reticulate bodies of Chlamydia trachomatis (LGV434) also were found to be deficient in cysteine-rich proteins and to be more susceptible to dissociation in sodium dodecyl sulfate than were outer membranes of elementary bodies. Images

Hatch, T P; Allan, I; Pearce, J H

1984-01-01

413

Life after HIV: examination of HIV serodiscordant couples' desire to conceive through assisted reproduction.  

PubMed

The current study addresses fertility desires and considerations among 143 HIV serodiscordant, opposite-sex couples (in which only the male partner is HIV positive) in the Northeastern U.S. Couples responded to questionnaires during their initial consultation for assisted reproduction, and data were collected over 7 years and analyzed retrospectively. Results indicated that a majority of the male participants had HIV when they met their partner, and a majority also disclosed their HIV status upon meeting. Most couples reported that they had previously discussed or considered a host of fertility-related issues, including the potential risk of HIV infection to the mother and the fetus during the process of fertility treatment. The majority of couples had also discussed the possibility that the male partner could die prematurely due to HIV/AIDS and had considered making arrangements for third-party parenting in the event of the male partner's death. If their fertility treatment were to be successful in the future, most couples desired additional children, and most believed that their future child should be told of the male partner's HIV status. Predictors of the desire for additional children after successful fertility treatment included: younger age, shorter relationship duration, being childless currently, and beginning their relationship after the male partner had already been diagnosed as HIV positive. Future research on fertility desires should include perspectives of HIV positive men on fatherhood, as well as concerns and issues specific to HIV serodiscordant couples. PMID:20960049

Gosselin, Jennifer T; Sauer, Mark V

2011-02-01

414

From The Cover: The structure of a thermophilic archaeal virus shows a double-stranded DNA viral capsid type that spans all domains of life  

Microsoft Academic Search

Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth 80°C)

George Rice; Liang Tang; Kenneth Stedman; Francisco Roberto; Josh Spuhler; Eric Gillitzer; John E. Johnson; Trevor Douglas; Mark Young

2004-01-01

415

The structure of a thermophilic archaeal virus shows a double-stranded DNA viral capsid type that spans all domains of life  

Microsoft Academic Search

Of the three domains of life (Eukarya, Bacteria, and Archaea), the least understood is Archaea and its associated viruses. Many Archaea are extremophiles, with species that are capable of growth at some of the highest temperatures and extremes of pH of all known organisms. Phylogenetic rRNA-encoding DNA analysis places many of the hyperthermophilic Archaea (species with an optimum growth >80°C)

George Rice; Liang Tang; Kenneth Stedman; Josh Spuhler; Eric Gillitzer; John E. Johnson; Trevor Douglas; Mark Young

416

4-H Study of Positive Youth Development: A Sample Case of Applying Principles of Developmental Measurement and Methodology to Assess the Development of Entrepreneurship Across the Life Span  

Microsoft Academic Search

SUMMARY The measures and design of a major, national longitudinal study of adolescent development-the 4-H Study of Positive Youth Development-reflect the methodological features needed to provide quantitative and qualitative data pertinent to the role of both (1) potential contextual bases of entrepreneurship (e.g., relating to family influences or mentors' roles); and (2) individual characteristics related to the life skills that

Jacqueline V. Lerner

417

Life history of yellow baboons: Physical development, reproductive parameters, and infant mortality  

Microsoft Academic Search

Longitudinal data from a population of yellow baboons,Papio cynocephalus, in the Amboseli National Park, Kenya, provide life history parameter estimates. Females reached menarche at approximately\\u000a four-and-a-half years of age and then cycled for approximately a year before first conception. Postpartum anestrum averaged\\u000a 12 months but ranged from six to 16 months. In cases of still births or infant death during

Jeanne Altmann; Stuart A. Altmann; Glenn Hausfater; Sue Ann McCuskey

1977-01-01

418

Life history of hamadryas baboons: Physical development, infant mortality, reproductive parameters and family relationships  

Microsoft Academic Search

Demographic and life history parameters were estimated for a band of free-ranging hamadryas baboons, observed for 5.5 years\\u000a in Ethiopia. Age-related changes in body weight and dentition were found to be delayed relative to laboratory-reared baboons.\\u000a On the average, females reached menarche at 4.3 years of age and had their first infant at the age of 6.1 years. The mean

H. Sigg; A. Stolba; J.-J. Abegglen; V. Dasser

1982-01-01

419

23. DETAIL VIEW OF FIXED SPAN SUBSTRUCTURE, EAST SPAN, SHOWING ...  

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

23. DETAIL VIEW OF FIXED SPAN SUBSTRUCTURE, EAST SPAN, SHOWING CONDITION OF GRANITE PIERS AND PILES OF ADJACENT PIER, LOOKING SOUTHEAST - Congress Street Bascule Bridge, Spanning Fort Point Channel at Congress Street, Boston, Suffolk County, MA

420

EAST END FROM MID SPAN OF EASTERN SPAN (THREE DIFFERENT ...  

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

EAST END FROM MID SPAN OF EASTERN SPAN (THREE DIFFERENT TRUSSES, EAST SOUTHEAST 110 DEGREES) - Honey Run Bridge, Spanning Butte Creek, bypassed section of Honey Run Road (originally Carr Hill Road), Paradise, Butte County, CA

421

View of approach span and movable span, looking southeast from ...  

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

View of approach span and movable span, looking southeast from navy land. Note that navigational channel exists only on north side of movable span. - Naval Supply Annex Stockton, Rough & Ready Island, Stockton, San Joaquin County, CA

422

REPRODUCTIVE DEVELOPMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Throughout history, humans have celebrated the beauty and fertility of flowering plants. In addition to their aesthetic appeal, flowers contain the reproductive organs of the plant and are therefore essential for sexual propagation of plant life. Our dependence on flowering is illustrated by the die...

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