Effects of age‐based movement on the estimation of growth assuming random‐at‐age or random‐at‐length data

Simulation methods were used to generate paired data from a simulated population that included the age‐based process of movement and the length‐based process of gear selection. The age‐based process caused bias in the estimates of growth parameters assuming random at length, even when relatively few age classes were affected. Methods that assumed random at age were biased by the subsequent inclusion of the length‐based process of gear selection. Additional knowledge of the age structure of the sampled area is needed to ensure an unbiased estimate of the growth parameters when using the length‐conditional approach in the presence of age‐based movement. Estimates of the variability in the length‐at‐age relationship were better estimated with the length‐conditional than the traditional method even when the assumptions of random at length were violated. Inclusion of paired observations of length and associated age inside the population dynamics model may be the most appropriate way of estimating growth.     

Age,sex and beauty: methodological dependence of age‐ and sex‐dichromatism in the great tit Parus major

Carotenoid‐based colour expression is frequently involved in sexual dichromatism, particularly in bird plumage, suggesting a role in sexual selection. Despite much work on expression of the carotenoid‐based ventral plumage coloration of the great tit (Parus major), which represents a popular model in evolution and ecology, a consensus on even the most basic demographic patterns of variation (e.g. age and sex differences) is lacking. This may reflect the use of variable methods for analysing colour variation, although what is not clear, either in this case or in general, is the extent to which these alternative methods are equally effective at describing age‐ and sex‐related dichromatism. Using data obtained over 4 years from a large sample of free‐ranging great tits, we examined how colour‐scoring methodology influences estimates of age‐ and sex‐related dichromatism. We compare: (1) principal components analysis‐derived scores; (2) tristimulus colour variables; (3) a visual model‐independent, carotenoid‐focussed colour score; and (4) two colour scoring methods based on avian visual models, examining how they assess colour variation with respect to age and sex to determine how methodology may influence results. We demonstrate clear age‐ and sex‐dependent expression of this colour trait, both in our own data and in meta‐analyses of results from great tit populations across Europe, and discuss the merits of the various colour scores, which yield very different estimates of the extent of age‐ and sex‐dependent dichromatism. We show variation is likely to be visible to conspecifics and propose a novel, visual model‐derived scoring system for describing variation in carotenoid‐based colour patches, where the perceived signal is divided into independent chromatic and achromatic components, in line with current understanding of visual perception. The present study highlights the impact of colour‐scoring methodology and shows that, as novel measures continue to be developed, researchers should consider carefully how they quantify colour expression. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 777–796.     

The short‐lived neon damsel Pomacentrus coelestis: implications for population dynamics

Daily increments of Pomacentrus coelestis, an abundant and well‐studied fish, were validated for the life of the fish and depending on the location, age‐maxima were estimated to be 127–160 days on reefs separated by tens to hundreds of kilometres on the Great Barrier Reef. This contrasts with congeners and other damselfishes that live for 5 years or more. Otoliths of P. coelestis were thinner and had different patterns of banding when compared with relatively long‐lived congeners. It is suggested that banding patterns in P. coelestis may be related to patterns of maturation and spawning. The consequences of a short life would have a great influence on the population dynamics of this widespread species. Further, the demographics and habitat preferences of this species suggest rapid colonization and establishment of breeding populations that would quickly change the relative abundance of sympatric fishes.     

Short‐ and long‐term effects on mAb‐producing CHO cell lines after cryopreservation

Cryopreservation provides the foundation for research, development, and manufacturing operations in the CHO‐based biopharmaceutical industry. Despite its criticality, studies are lacking that explicitly demonstrate that the routine cell banking process and the potential stress and damage during cryopreservation and recovery from thaw have no lasting detrimental effects on CHO cells. Statistics are also scarce on the decline of cell‐specific productivity (Q_p) over time for recombinant CHO cells developed using the glutamine synthetase (GS)‐based methionine sulfoximine (MSX) selection system. To address these gaps, we evaluated the impact of freeze‐thaw on 24 recombinant CHO cell lines (generated by the GS/MSX selection system) using a series of production culture assays. Across the panel of cell lines expressing one of three monoclonal antibodies (mAbs), freeze‐thaw did not result in any significant impact beyond the initial post‐thaw passages. Production cultures sourced from cryopreserved cells and their non‐cryopreserved counterparts yielded similar performance (growth, viability, and productivity), product quality (size, charge, and glycosylation distributions), and flow cytometric profiles (intracellular mAb expression). However, many production cultures yielded lower Q_p at increased cell age: 17 of the 24 cell lines displayed ≥20% Q_p decline after ～2–3 months of passaging, irrespective of whether the cells were previously cryopreserved. The frequency of Q_p decline underscores the continued need for understanding the underlying mechanisms and for careful clone selection. Because our experiments were designed to decouple the effects of cryopreservation from those of cell age, we could conclusively rule out freeze‐thaw as a cause for Q_p decline. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:463–477, 2018     

Prenatal data impacts common bottlenose dolphin (Tursiops truncatus) growth parameters estimated by length‐at‐age curves

Compilation of marine mammal demographic data is central to management efforts. However, marine mammal length‐at‐age growth curves demonstrate limitations. Physiological growth parameters of terrestrial mammals are typically estimated using curvilinear models fit to size‐at‐age data along a time series from conception to senescence. The difficulty of collecting and aging prenatal cetaceans is addressed here, and growth parameters of common bottlenose dolphins (Tursiops truncatus) along coastal Texas were estimated using length‐at‐age information from a broader scope of age classes, including late‐term fetuses. A Gompertz growth curve fit to pre‐ and postnatal data underestimated size parameters, but demonstrated similar growth rate constants (k) to an exclusively postnatal model. However, when growth parameters were broken out, the absolute growth rate (G) and rate of growth decay (g) decreased (0.44 from 0.27 and 0.55 from 0.39, respectively), which underscores the importance of reporting k in its expanded form (G/g). Although the Gompertz fits most age classes well, it cannot explain growth in all age classes. We argue that a novel sigmoidal model would be more useful for inference.     

Daily growth patterns and age‐at‐recruitment of the anchoveta Engraulis ringens as indicated by a multi‐annual analysis of otolith microstructure across developmental stages

The anchoveta (Engraulis ringens ) plays a key role in the ecology of the Humboldt Current System and is of major economic importance; however, many aspects of its early life history are still poorly understood. In this study, an analysis of daily age and length patterns was carried out using the sagittal otoliths from wild larvae (0–0.2 cm standard length, L _S), pre‐recruits (3–6 cm total length, L _T), recruits (7–12 cm L _T) and young adults (12–15 cm L _T). Additionally, variability in growth and age at recruitment (A _R) were evaluated for recruits caught in northern Chile in 1973, 1982, 2009, 2010, 2012, 2013, 2014 and 2015. The age–length relationship showed four allometric patterns that were well described by Laird‐Gompertz models. The absolute growth rates at the inflexion point (G _AR) were 0.56, 0.75, 1.22 and 1.16 mm d^?1 for larvae, pre‐recruits, recruits and young adults, respectively. At the interannual scale, G _AR values were always >1 mm d^?1 (mean ± S.D . 1.37 ± 0.21 mm d^?1; range 1.12–1.64 mm d^?1), irrespective of the season of hatching (i.e. winter v. spring); additionally, in most cases, G _AR values were reached before the second month of life (mean ± S.D . 50.47 ± 9.73 days) at c. 4 cm L _T (mean ± S.D . 4.22 ± 0.29 cm). Mean A _R was < 150 days (112 ± 29 days; range 75–149 days); in contrast, estimates of A _R were higher and growth rates were lower in 1973, 1983 and 2000. These results demonstrate very fast growth and early A _R of anchoveta in northern Chile, suggesting most fish are removed by the fisheries at very early ages. An evaluation of the implications of these results on stock assessment and management of this species is highly recommended.     

Geographical variation in reproductive ageing patterns and life‐history strategy of a short‐lived passerine bird

We investigated differences in ageing patterns in three measures of breeding performance in populations of barn swallows Hirundo rustica L. from Spain and Denmark differing in breeding latitude and hence migration distance and duration of the breeding season. We found differences in ageing patterns between populations. Generally, young (i.e. yearling) and old females (i.e. ≥ 5 years of age) laid their first eggs later and produced smaller clutches than middle‐aged females (i.e. 2–4 years of age) in both populations. The southernmost population (i.e. Spanish) showing the shorter migratory distance experienced a greater within‐individual increase in timing of breeding and clutch size in early life and a greater within‐individual decrease in laying date but not in clutch size during senescence compared with the northernmost population (i.e. Danish). We also found that the number of fledglings produced annually was related to the age of the two members of the breeding pairs with pairs composed of young and old females performing less well than breeding pairs composed of middle‐aged females. We did not find reproductive senescence for the age of the male while controlling for the age of the female on the number of fledglings produced annually by the breeding pair. Differential survival between individuals did not explain age effects on laying date or annual clutch size in neither population. However, the increase in the number of fledglings produced annually with age was partly explained by the disappearance of poor‐quality members of the pairs, mainly poor‐quality males. Age‐related breeding success (i.e. number of fledglings) was similar for barn swallows from Spain and Denmark. Therefore, the study of ageing patterns and life‐history strategies in free‐ranging animals from more than a single population can throw new light on life‐history theory, population dynamics and evolutionary studies of senescence.     

Adult dietary protein has age‐ and context‐dependent effects on male post‐copulatory performance

The highly conserved effect of dietary protein restriction on lifespan and ageing is observed in both sexes and across a vast range of taxa. This extension of lifespan is frequently accompanied by a reduction in female fecundity, and it has been hypothesized that individuals may reallocate resources away from reproduction and into somatic maintenance. However, effects of dietary protein restriction on male reproduction are less consistent, suggesting that these effects may depend on other environmental parameters. Using the neriid fly, Telostylinus angusticollis, we examined age‐specific effects of adult dietary protein restriction on male post‐copulatory reproductive performance (fecundity and offspring viability). To explore the context dependence of these effects, we simultaneously manipulated male larval diet and adult mating history. We found that protein‐restricted males sired less viable offspring at young ages, but offspring viability increased with paternal age and eventually exceeded that of fully fed males. The number of eggs laid by females was not affected by male dietary protein, whereas egg hatching success was subject to a complex interaction of male adult diet, age, larval diet and mating history. These findings suggest that effects of protein restriction on male reproduction are highly context dependent and cannot be explained by a simple reallocation of resources from reproduction to somatic maintenance. Rather, these effects appear to involve changes in the scheduling of male reproductive investment with age.     

Mobilization‐based transplantation of young‐donor hematopoietic stem cells extends lifespan in mice

Mammalian aging is associated with reduced tissue regeneration and loss of physiological integrity. With age, stem cells diminish in their ability to regenerate adult tissues, likely contributing to age‐related morbidity. Thus, we replaced aged hematopoietic stem cells (HSCs) with young‐donor HSCs using a novel mobilization‐enabled hematopoietic stem cell transplantation (HSCT) technology as an alternative to the highly toxic conditioning regimens used in conventional HSCT. Using this approach, we are the first to report an increase in median lifespan (12%) and a decrease in overall mortality hazard (HR: 0.42, CI: 0.273–0.638) in aged mice following transplantation of young‐donor HSCs. The increase in longevity was accompanied by reductions of frailty measures and increases in food intake and body weight of aged recipients. Young‐donor HSCs not only preserved youthful function within the aged bone marrow stroma, but also at least partially ameliorated dysfunctional hematopoietic phenotypes of aged recipients. This compelling evidence that mammalian health and lifespan can be extended through stem cell therapy adds a new category to the very limited list of successful anti‐aging/life‐extending interventions. Our findings have implications for further development of stem cell therapies for increasing health and lifespan.     

Technical note: False catastrophic age‐at‐death profiles in commingled bone deposits

Age‐at‐death profiles obtained using the minimum number of individuals (MNI) for mass deposits of commingled human remains may be biased by over‐representation of subadult individuals. A computer simulation designed in the R environment has shown that this effect may lead to misinterpretation of such samples even in cases where the completeness rate is relatively high. The simulation demonstrates that the use of the Most Likely Number of Individuals (MLNI) substantially reduces this bias. Am J Phys Anthropol 152:554–557, 2013. © 2013 Wiley Periodicals, Inc.     

Physical maturation,life‐history classes and age estimates of free‐ranging western gorillas—insights from Mbeli Bai,Republic of Congo

Physical maturation and life‐history parameters are seen as evolutionary adaptations to different ecological and social conditions. Comparison of life‐history patterns of closely related species living in diverse environments helps to evaluate the validity of these assumptions but empirical data are lacking. The two gorilla species exhibit substantial differences in their environment, which allows investigation into the role of increased frugivory in shaping western gorilla life histories. We present behavioral and morphological data on western gorilla physical maturation and life‐history parameters from a 12.5‐year study at Mbeli Bai, a forest clearing in the Nouabalé‐Ndoki National Park in northern Congo. We assign photographs of known individuals to different life‐history classes and propose new age boundaries for life‐history classes in western gorillas, which can be used and tested at other western gorilla research sites. Our results show that western gorillas are weaned at a later age compared with mountain gorillas and indicate slower physical maturation of immatures. These findings support the risk‐aversion hypothesis for more frugivorous species. However, our methods need to be applied and tested with other gorilla populations. The slow life histories of western gorillas could have major consequences for social structure, mortality patterns and population growth rates that will affect recovery from population crashes of this critically endangered species. We emphasize that long‐term studies can provide crucial demographic and life‐history data that improve our understanding of life‐history evolution and adaptation and help to refine conservation strategies. Am. J. Primatol. 71:106–119, 2009. © 2008 Wiley‐Liss, Inc.     

Gestational age‐dependent gene expression profiling of ATP‐binding cassette transporters in the healthy human placenta

The ATP‐binding cassette (ABC) transporters control placental transfer of several nutrients, steroids, immunological factors, chemicals, and drugs at the maternal‐fetal interface. We and others have demonstrated a gestational age‐dependent expression pattern of two ABC transporters, P‐glycoprotein and breast cancer resistance protein throughout pregnancy. However, no reports have comprehensively elucidated the expression pattern of all 50 ABC proteins, comparing first trimester and term human placentae. We hypothesized that placental ABC transporters are expressed in a gestational‐age dependent manner in normal human pregnancy. Using the TaqMan^® Human ABC Transporter Array, we assessed the mRNA expression of all 50 ABC transporters in first (first trimester, n = 8) and third trimester (term, n = 12) human placentae and validated the resulting expression of selected ABC transporters using qPCR, Western blot and immunohistochemistry. A distinct gene expression profile of 30 ABC transporters was observed comparing first trimester vs. term placentae. Using individual qPCR in selected genes, we validated the increased expression of ABCA1 (P < 0.01), ABCA6 (P < 0.001), ABCA9 (P < 0.001) and ABCC3 (P < 0.001), as well as the decreased expression of ABCB11 (P < 0.001) and ABCG4 (P < 0.01) with advancing gestation. One important lipid transporter, ABCA6, was selected to correlate protein abundance and characterize tissue localization. ABCA6 exhibited increased protein expression towards term and was predominantly localized to syncytiotrophoblast cells. In conclusion, expression patterns of placental ABC transporters change as a function of gestational age. These changes are likely fundamental to a healthy pregnancy given the critical role that these transporters play in the regulation of steroidogenesis, immunological responses, and placental barrier function and integrity.     

lncRNA H19 contributes to oxidative damage repair in the early age‐related cataract by regulating miR‐29a/TDG axis

Age‐related cataract (ARC) is caused by the exposure of the lens to UVB which promotes oxidative damage and cell death. This study aimed to explore the role of lncRNA H19 in oxidative damage repair in early ARC. lncRNAs sequencing technique was used to identify different lncRNAs in the lens of early ARC patients. Human lens epithelial cells (HLECs) were exposed to ultraviolet irradiation; and 8‐OHdG ELISA, Cell counting kit 8 (CCK8), EDU, flow cytometry and TUNEL assays were used to detect DNA damage, cell viability, proliferation and apoptosis. Luciferase assay was used to examine the interaction among H19, miR‐29a and thymine DNA glycosylase (TDG) 3'UTR. We found that lncRNA H19 and TDG were highly expressed while miR‐29a was down‐regulated in the three types of early ARC and HLECs exposed to ultraviolet irradiation, compared to respective controls. lncRNA H19 knockdown aggravated oxidative damage, reduced cell viability and proliferation, and promoted apoptosis in HLECs, while lncRNA H19 overexpression led to opposite effects in HLECs. Mechanistically, miR‐29a bound TDG 3'UTR to repress TDG expression. lncRNA H19 up‐regulated the expression of TDG by repressing miR‐29a because it acted as ceRNA through sponging miR‐29a. In conclusion, the interaction among lncRNA H19, miR‐29a and TDG is involved in early ARC. lncRNA H19 could be a useful marker of early ARC and oxidative damage repair pathway of lncRNA H19/miR‐29a/TDG may be a promising target for the treatment of ARC.     

Age‐dependent changes in infidelity in Seychelles warblers

Extra‐pair paternity (EPP) is often linked to male age in socially monogamous vertebrates; that is, older males are more likely to gain EPP and less likely to be cuckolded. However, whether this occurs because males improve at gaining paternity as they grow older, or because “higher quality” males that live longer are preferred by females, has rarely been tested, despite being central to our understanding of the evolutionary drivers of female infidelity. Moreover, how extra‐pair reproduction changes with age within females has received even less attention. Using 18 years of longitudinal data from an individually marked population of Seychelles warblers (Acrocephalus sechellensis), we found considerable within‐individual changes in extra‐pair reproduction in both sexes: an early‐life increase and a late‐life decline. Furthermore, males were cuckolded less as they aged. Our results indicate that in this species age‐related patterns of extra‐pair reproduction are determined by within‐individual changes with age, rather than differences among individuals in longevity. These results challenge the hypothesis—based on longevity reflecting intrinsic quality—that the association between male age and EPP is due to females seeking high‐quality paternal genes for offspring. Importantly, EPP accounted for up to half of male reproductive success, emphasizing the male fitness benefits of this reproductive strategy. Finally, the occurrence of post‐peak declines in extra‐pair reproduction provides explicit evidence of senescence in infidelity in both males and females.     

Application of NMR spectroscopy for assignment of the absolute configuration of 8‐tert‐butyl‐2‐hydroxy‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]dec‐6‐en‐10‐one

In order to assign the absolute configurations of 8‐tert‐butyl‐2‐hydroxy‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]dec‐6‐en‐10‐one ( 2a , 2b ), their esters ( 5a , 5b , 5c , 5d ) with (R)‐ or (S)‐2‐methoxyphenylacetic acid ( 4a , 4b ) have been synthesized. The absolute configurations of these compounds have been determined on the basis of NOESY correlations between the protons of the tert‐butyl group and the cyclopentane fragment of the molecules. The crucial part of this analysis was assignment of the absolute configuration at C‐5. Additionally, by calculation of the chemical shift anisotropy, δ^RS, for the relevant protons, it was also possible to confirm the absolute configurations at the C‐2 centres of compounds 2a , 2b and 5a , 5b , 5c , 5d . Chirality, 25:422–426, 2013.© 2013 Wiley Periodicals, Inc.