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Physiological Stress (physiological + stress)
Terms modified by Physiological Stress Selected AbstractsPsychological and Physiological Stress: Impact on Preterm BirthJOURNAL OF OBSTETRIC, GYNECOLOGIC & NEONATAL NURSING, Issue 5 2003FAAN professor, Susan Gennaro DSN Stress increases corticotropin-releasing hormone and may ultimately result in increased uterine contractility. Stress also increases cytokine production, which independently may lead to preterm birth or increase susceptibility to infection, thereby increasing the risk of preterm birth. Finally, stress may change health behaviors that lead to preterm birth. Research findings on the relationship between stress and preterm birth have been contradictory. In this article, the authors propose a model of the relationship between stress and preterm birth, evaluate the research on stress and pregnancy outcomes, and discuss the implications for nursing practice and research. [source] Species richness and susceptibility to heat and drought extremes in synthesized grassland ecosystems: compositional vs physiological effectsFUNCTIONAL ECOLOGY, Issue 6 2004L. VAN PEER Summary 1We investigated effects of declining plant species richness (S) on resistance to extremes in grassland communities. 2Synthesized model ecosystems of different S, grown outdoors in containers, were exposed to a stress peak combining heat and drought. The heat wave was induced experimentally by infrared irradiation in free air conditions. 3Before the heat wave, the more species-rich communities produced more biomass as a result of a large and positive complementarity effect that outweighed a small negative selection effect. 4Water use during the heat wave was likewise enhanced by S, which could not be attributed to dominance of ,water-wasting' species. Instead, water consumption at high S exceeded that expected from changes in community biomass and biomass composition. The observed enhancement of resource (water) acquisition under stress with increasing S therefore probably originated from complementarity. 5Despite enhanced water use in the more diverse communities, plant survival was significantly less, affecting all species alike. Physiological stress, recorded as photochemical efficiency of photosystem II electron transport, was significantly greater. Before the heat wave, the changes in biomass composition that coincided with increasing S did not favour species that would later prove intrinsically sensitive or insensitive. 6Complementarity in resource use for biomass production had a cost in terms of reduced survival under stress, despite the likelihood of complementarity in water acquisition during exposure. The greater loss of individuals from the more diverse grasslands suggests enhanced risk of local extinction. [source] Elevation of anions in exercise-induced acidosis: a study by ion-exchange chromatography/mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 3 2008William McKinnon Abstract Acidosis is a major factor that determines the upper limit of exercise endurance. We have previously shown that anions usually associated with intermediary metabolism are elevated in critically ill patients with metabolic acidosis and contribute significantly to acidosis generation. This study was to determine whether volunteers with normal metabolism would exhibit similar elevations in anions associated with intermediate metabolism when exposed to a short-term physiological stress leading to a brief lactic acidosis. Physiological stress was induced on five healthy male subjects by means of a ramped exercise protocol. Blood was obtained immediately prior to and post-exercise, plasma ultrafiltrate was prepared and analysed immediately both by enzyme assay and liquid chromatography coupled to electrospray,mass spectrometry (LC/ESI-MS). Metabolic acidosis concomitant with a significant increase in blood lactate occurred in each subject, but in addition, anions normally associated with intermediate metabolism were significantly elevated after exercise. The contribution of these anions to generating an acidosis, and thus potentially limiting the extent of exercise, has never been acknowledged. Copyright © 2007 John Wiley & Sons, Ltd. [source] Noninvasive Stress and Reproductive Measures of Social and Ecological Pressures in Free-Ranging African ElephantsCONSERVATION BIOLOGY, Issue 4 2001C. A. H. Foley This, coupled with political pressures to delist the elephant, has created a need for noninvasive physiological measures that can quantify the long-term effects of past mortality patterns of this long-lived species. We collected fresh fecal samples from 16 female elephants in three different groups over 23 months at Tarangire National Park, Tanzania, and analyzed them for fecal progesterone and cortisol metabolites. Social and ecological measures were collected concurrently. Fecal progesterone metabolite measures corresponded significantly with stage of gestation, and appear to be able to confirm pregnancy in female elephants from as early as 3 months of gestation. We found that progesterone metabolite concentrations were significantly lower during the dry season than during the wet season after controlling for stage of gestation. Fecal cortisol metabolite concentrations showed the opposite seasonal pattern, being significantly higher in the dry season and inversely correlated with rainfall across seasons. Fecal cortisol metabolite concentrations also increased with group size and were correlated positively with dominance rank in the largest group. Our results suggest that measures of progesterone and cortisol metabolites in feces provide indices of reproductive function and physiological stress that can quantify both natural and human disturbances in African elephants. These measures are ideally suited for monitoring the long-term effects of social disruption from poaching and a variety of other management concerns. Resumen: Debido a la cacería furtiva, la población de elefante africano ( Loxodonta africana) declinó en un 60%, principalmente adultos, entre 1979 y 1988. Esto, aunado a presiones políticas para eliminar al elefante de las listas de especies en peligro, ha creado la necesidad de medidas fisiológicas no invasivas que puedan cuantificar efectos a largo plazo de patrones de mortalidad en el pasado de esta especie longeva. Recolectamos muestras fecales de 16 elefantes hembras en tres grupos diferentes en el Parque Nacional Tarangire, Tanzania a lo largo de 23 meses, y las analizamos para detectar metabolitos de progesterona fecal y de cortisol. Al mismo tiempo se recolectaron medidas sociales y ecológicas. Las medidas de metabolitos de progesterona fecal correspondieron significativamente con la etapa de gestación, y parecen permitir la confirmación de preñez en elefantes hembras tan temprano como a los tres meses de gestación. Las concentraciones de metabolitos de progesterona fueron significativamente menores durante la época de sequía que en la de lluvias después de controlar para la etapa de gestación. Las concentraciones de metabolitos de cortisol fecal mostraron un patrón estacional opuesto, siendo significativamente más altas en la época de sequía e inversamente correlacionados con la precipitación en todas las estaciones. Las concentraciones de metabolitos de cortisol fecal también incrementaron con el tamaño del grupo y se correlacionaron positivamente con el rango de dominancia en el grupo más grande. Nuestros resultados sugieren que las medidas de metabolitos de progesterona y cortisol en las heces proporcionan índices de la función reproductiva y del estrés fisiológico que puede cuantificar perturbaciones, tanto naturales como humanas, en elefantes africanos. Estas medidas son idealmente adecuadas para monitorear efectos a largo plazo de la disrupción social por la cacería furtiva y así como una variedad de aspectos del manejo. [source] Crowding and disease: effects of host density on response to infection in a butterfly,parasite interactionECOLOGICAL ENTOMOLOGY, Issue 5 2009ELIZABETH LINDSEY Abstract. 1. Hosts experiencing frequent variation in density are thought to benefit from allocating more resources to parasite defence when density is high (,density-dependent prophylaxis'). However, high density conditions can increase intra-specific competition and induce physiological stress, hence increasing host susceptibility to infection (,crowding-stress hypothesis'). 2. We studied monarch butterflies (Danaus plexippus) and quantified the effects of larval rearing density on susceptibility to the protozoan parasite Ophryocystis elektroscirrha. Larvae were inoculated with parasite spores and reared at three density treatments: low, moderate, and high. We examined the effects of larval density on parasite loads, host survival, development rates, body size, and wing melanism. 3. Results showed an increase in infection probability with greater larval density. Monarchs in the moderate and high density treatments also suffered the greatest negative effects of parasite infection on body size, development rate, and adult longevity. 4. We observed greater body sizes and shorter development times for monarchs reared at moderate densities, and this was true for both unparasitised and parasite-treated monarchs. We hypothesise that this effect could result from greater larval feeding rates at moderate densities, combined with greater physiological stress at the highest densities. 5. Although monarch larvae are assumed to occur at very low densities in the wild, an analysis of continent-wide monarch larval abundance data showed that larval densities can reach high levels in year-round resident populations and during the late phase of the breeding season. Treatment levels used in our experiment captured ecologically-relevant variation in larval density observed in the wild. [source] The ontogeny of foragwehaviour in desert ants, Cataglyphis bicolorECOLOGICAL ENTOMOLOGY, Issue 2 2004Rüdiger Wehner Abstract. 1. Individually foraging desert ants, Cataglyphis bicolor, exhibit short foraging lives (half lifetime, i.e. half-time of the exponential decay function: 4.5 days), in which they perform 3.7 ± 1.9 foraging runs per day. 2. During their short lifetime foraging period the ants increase the duration of their foraging round trips (up to 40.0 ± 24.6 min per run), the maximal distance of individual foraging runs (up to 28.2 ± 4.1 m), and their foraging success, i.e. the ratio of successful runs to the total number of runs (up to 0.70). 3. The parameter that increases most dramatically during a forager's lifetime is direction fidelity, i.e. the tendency to remain faithful to a particular foraging direction. 4. A model based on some simple behavioural rules is used to describe the experimental findings that within an isotropic food environment individual ants develop spatial foraging idiosyncrasies, and do so at a rate that increases with the food densities they encounter. 5. Finally, it is argued that in functional terms direction fidelity is related to the navigational benefits resulting from exploiting familiar (route-based) landmark information, and hence reduces round-trip time and by this physiological stress and predatory risk. [source] New organochlorine contaminants and metabolites in plasma and eggs of glaucous gulls (Larus hyperboreus) from the Norwegian ArcticENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2005Jonathan Verreault Abstract The present study investigated new or lesser-studied and legacy organochlorine (OC) contaminants and metabolites in plasma and eggs of glaucous gulls (Larus hyperboreus) collected from major breeding colonies on Bear Island in the Norwegian Arctic. Hexachlorobutadiene was below the method limit of detection (<0.07 ng/g lipid wt) in all samples. The sum (sum) of 20 chlorobornane congener concentrations ranged between 294 and 986 ng/g lipid weight and 104 and 1,121 ng/g lipid weight in plasma and eggs, respectively, whereas those of ,20polychlorinated naphthalene ranged between 1.34 and 126 ng/g lipid weight in plasma and 1.82 and 162 ng/g lipid weight in eggs. Bis(4-chlorophenyl) sulfone concentrations ranged between 5.24 and 143 ng/g lipid weight plasma, which is the first report of this contaminant in arctic biota north of Sweden. Based on 2,3,7,8-tetrachlorodibenzo- p -dioxin toxic equivalents (TEQs), partial dioxin-like toxicity varied between 3.04 and 20.8 ng TEQ/g lipid weight in plasma and 0.94 and 46.5 ng TEQ/g lipid weight in eggs, and largely was due to concentrations of non- ortho polychlorinated biphenyls (PCBs), with a very minor contribution from mono- ortho PCBs and polychlorinated naphthalenes. The major aryl sulfone metabolite in plasma was an unidentified hexachlorinated MeSO2 -PCB congener (range: 13.5,551 ng/g lipid wt), whereas the pentachlorinated congeners 3,- and 4,-MeSO2 -CB101 (range: 4.49,38.1 ng/g lipid wt) dominated in eggs. The predominant halogenated phenolic compound (HPC) in plasma was consistently the PCB metabolite 4-OH-CB187 (range: 0.29,17.5 ng/g wet wt), whereas in eggs, detectable HPCs were at very low and transient concentrations. As part of a complex profile of contaminant exposure, these chemical classes and metabolites may be contributing factors to enhance physiological stress in breeding glaucous gulls. [source] What can developmental defects of enamel reveal about physiological stress in nonhuman primates?EVOLUTIONARY ANTHROPOLOGY, Issue 4 2001Debbie Guatelli-Steinberg First page of article [source] Molecular characterization of artemin and ferritin from Artemia franciscanaFEBS JOURNAL, Issue 1 2003Tao Chen Embryos of the brine shrimp, Artemia franciscana, exhibit remarkable resistance to physiological stress, which is temporally correlated with the presence of two proteins, one a small heat shock/,-crystallin protein termed p26 and the other called artemin, of unknown function. Artemin was sequenced previously by Edman degradation, and its relationship to ferritin, an iron storage protein, established. The isolation from an Artemia expressed sequence tag library of artemin and ferritin cDNAs extends this work. Artemin cDNA was found to contain an ORF of 693 nucleotides, and its deduced amino-acid sequence, except for the initiator methionine, was identical with that determined previously. Ferritin cDNA is 725 bp in length with an ORF of 516 nucleotides. Artemin amino-acid residues 32,185 are most similar to ferritin, but artemin is enriched in cysteines. The abundance of cysteines and their intramolecular spatial distribution suggest that artemin protects embryos against oxidative damage and/or that its function is redox regulated. The conserved regions in artemin and ferritin monomers are structurally similar to one another and both proteins assemble into oligomers. However, modeling of the quaternary structure indicated that artemin multimers lack the central space used for metal storage that characterizes ferritin oligomers, implying different roles for this protein. Probing of Northern blots revealed two artemin transcripts, one of 3.5 kb and another of 2.2 kb. These transcripts decreased in parallel and had almost disappeared by 16 h of development. The ferritin transcript of 0.8 kb increased slightly during reinitiation of development, then declined, and was almost completely gone by 16 h. Clearly, the loss of artemin and ferritin during embryo development is due to transcriptional regulation and proteolytic degradation of the proteins. [source] Evaluating the physiological and physical consequences of capture on post-release survivorship in large pelagic fishesFISHERIES MANAGEMENT & ECOLOGY, Issue 2 2007G. B. SKOMAL Abstract, Sharks, tunas and billfishes are fished extensively throughout the world. Domestic and international management measures (quotas, minimum sizes, bag limits) mandate release of a large, yet poorly quantified, number of these fishes annually. Post-release survivorship is difficult to evaluate, because standard methods are not applicable to large oceanic fishes. This paper presents information on the current approaches to characterising capture stress and survivorship in sharks, tunas and marlins. To assess mortality associated with capture stress, researchers must examine the cumulative impacts of physical trauma and physiological stress. Physical trauma, manifested as external and internal tissue and organ damage, is caused by fishing gear and handling. Gross examination and histopathological sampling have been used to assess physical trauma and to infer post-release survivorship. Exhaustive anaerobic muscular activity and time out of water cause physiological stress, which has been quantified in these fishes through the analyses of blood chemistry. Conventional, acoustic and archival tagging have been used to assess post-release survivorship in these species. Future studies relating capture stress and post-release survivorship could yield information that helps fishermen increase survivorship when practicing catch and release. [source] Relative contributions from exposed inshore and estuarine nursery grounds to the recruitment of stone flounder, Platichthys bicoloratus, estimated using otolith Sr:Ca ratiosFISHERIES OCEANOGRAPHY, Issue 4 2000Yoh Yamashita In Sendai Bay, stone flounder larvae settle and spend their juvenile period in either shallow exposed inshore nursery grounds or estuarine nursery grounds. The purpose of this study is to examine the relative contributions of these two kinds of nursery grounds to the flounder population using otolith strontium:calcium ratios. Stone flounder juveniles were collected from both nursery grounds, and one- and two-year-old flounder were caught deeper in Sendai Bay. Sr and Ca content in the otoliths were measured by electron probe micro analysis. The Sr:Ca ratios in the otolith section corresponding to the early postsettlement period ranged from 3.06 to 3.85 for the exposed inshore areas with stable low temperature and high salinity conditions, and from 3.81 to 5.32 in brackish estuaries with high temperature and low salinity conditions but with large diel and tidal cyclical fluctuations. Values from an estuarine site with stable salinity ranged from 3.58 to 4.15 overlapping with both the above ranges. Rearing experiments supported our inference that the high otolith Sr:Ca ratios of juveniles inhabiting estuarine nursery grounds are attributable to higher temperature and physiological stress caused by the large diel temperature and salinity fluctuations within the estuaries. Estimation of the Sr:Ca ratio of recruited fish using the otolith section formed while in the nursery area showed that at least 20 out of 42 individuals examined originated from estuarine nursery grounds. The present study indicates that estuaries play an important role as nursery grounds for stone flounder, producing about half of the stock in spite of the small and restricted area compared with the wide expanse of the exposed inshore area. [source] Patterns of ant species richness along elevational gradients in an arid ecosystemGLOBAL ECOLOGY, Issue 2 2003Nathan J. Sanders ABSTRACT Aim In this study, we examine patterns of local and regional ant species richness along three elevational gradients in an arid ecosystem. In addition, we test the hypothesis that changes in ant species richness with elevation are related to elevation-dependent changes in climate and available area. Location Spring Mountains, Nevada, U.S.A. Methods We used pitfall traps placed at each 100-m elevational band in three canyons in the Spring Mountains. We compiled climate data from 68 nearby weather stations. We used multiple regression analysis to examine the effects of annual precipitation, average July precipitation, and maximum and minimum July temperature on ant species richness at each elevational band. Results We found that patterns of local ant species richness differed among the three gradients we sampled. Ant species richness increased linearly with elevation along two transects and peaked at mid-elevation along a third transect. This suggests that patterns of species richness based on data from single transects may not generalize to larger spatial scales. Cluster analysis of community similarity revealed a high-elevation species assemblage largely distinct from that of lower elevations. Major changes in the identity of ant species present along elevational gradients tended to coincide with changes in the dominant vegetation. Regional species richness, defined here as the total number of unique species within an elevational band in all three gradients combined, tended to increase with increasing elevation. Available area decreased with increasing elevation. Area was therefore correlated negatively with ant species richness and did not explain elevational patterns of ant species richness in the Spring Mountains. Mean July maximum and minimum temperature, July precipitation and annual precipitation combined to explain 80% of the variation in ant species richness. Main conclusions Our results suggest that in arid ecosystems, species richness for some taxa may be highest at high elevations, where lower temperatures and higher precipitation may support higher levels of primary production and cause lower levels of physiological stress. [source] Ergonomic issues in team liftingHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 3 2005R.S. Barrett In this article we review and critique the current body of scientific knowledge regarding the use of team lifting including: (a) psychophysical studies of team lifting capacity, and (b) studies of manual handling, patient handling, and stretcher carriage performed by lifting teams. The consensus of the research literature is that team-lifting capacity is greater than the lifting capacity of an individual, but that the capacity of lifting teams is less than the summed capacity of individual team members. Further, biomechanical, psychophysical, and physiological stress tends to be reduced compared to the equivalent lifts and transfers performed by individuals. However, the stress associated with team lifting depends on a broad range of individual team member, load, task and environmental factors, which can interact in unexpected ways. Caution is therefore recommended against making broad assumptions regarding the use of team lifting. Future studies are needed to examine how effort and load are distributed among lifting team members, with emphasis on identifying factors that may increase the risk of injury. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 293,307, 2005. [source] Physiological response to stress in fledgling Lesser Kestrels Falco naumanni: the role of physical condition, sex and individual genetic diversityIBIS, Issue 3 2009JOAQUÍN ORTEGO Exposure to chronic stress early on during development has important deleterious consequences later in life, reducing important components of individual fitness such as survival and future reproduction. In this study, we evaluate the factors associated with physiological response to stress in fledgling Lesser Kestrels Falco naumanni, paying particular attention to the potential role of individual genetic diversity. For this purpose, we used heterophil/lymphocyte ratios (H/L ratio) as a haematological stress indicator and typed the analysed individuals at 11 highly polymorphic microsatellite loci, which allowed us to estimate their genetic diversity. We found that the H/L ratio decreases with fledgling physical condition, suggesting that this parameter is a good indicator of nutritionally based physiological stress. Physiological response to stress was higher in males than in females and this effect was independent of physical condition, suggesting that the observed pattern is due to inherent sexual differences in the factors influencing H/L ratios. Finally, the H/L ratio was positively associated with the genetic diversity of offspring. Previous experimental studies have found that individuals with higher genetic diversity show increased levels of circulating glucocorticoids, which in turn are directly responsible for increasing H/L ratios. On this basis, we suggest that a positive effect of genetic diversity on corticosterone levels may explain the observed association between H/L ratios and individual heterozygosity. Overall, this study highlights the utility of leucocyte profiles to study stress in wild bird populations and poses an interesting question about the effects of individual genetic diversity on haematological response to stress. [source] The sensitive hare: sublethal effects of predator stress on reproduction in snowshoe haresJOURNAL OF ANIMAL ECOLOGY, Issue 6 2009Michael J. Sheriff Summary 1.,Prey responses to high predation risk can be morphological or behavioural and ultimately come at the cost of survival, growth, body condition, or reproduction. These sub-lethal predator effects have been shown to be mediated by physiological stress. We tested the hypothesis that elevated glucocorticoid concentrations directly cause a decline in reproduction in individual free-ranging female snowshoe hares, Lepus americanus. We measured the cortisol concentration from each dam (using a faecal analysis enzyme immunoassay) and her reproductive output (litter size, offspring birth mass, offspring right hind foot (RHF) length) 30 h after birth. 2.,In a natural monitoring study, we monitored hares during the first and second litter from the population peak (2006) to the second year of the decline (2008). We found that faecal cortisol metabolite (FCM) concentration in dams decreased 52% from the first to the second litter. From the first to the second litter, litter size increased 122%, offspring body mass increased 130%, and offspring RHF length increased 112%. Dam FCM concentrations were inversely related to litter size (r2 = 0·19), to offspring birth mass (r2 = 0·32), and to offspring RHF length (r2 = 0·64). 3.,In an experimental manipulation, we assigned wild-caught, pregnant hares to a control and a stressed group and held them in pens. Hares in the stressed group were exposed to a dog 1,2 min every other day before parturition to simulate high predation risk. At parturition, unsuccessful-stressed dams (those that failed to give birth to live young) and stressed dams had 837% and 214%, respectively, higher FCM concentrations than control dams. Of those females that gave birth, litter size was similar between control and stressed dams. However, offspring from stressed dams were 37% lighter and 16% smaller than offspring from control dams. Increasing FCM concentration in dams caused the decline of offspring body mass (r2 = 0·57) and RHF (r2 = 0·52). 4.,This is the first study in a free-ranging population of mammals to show that elevated, predator-induced, glucocorticoid concentrations in individual dams caused a decline in their reproductive output measured both by number and quality of offspring. Thus, we provide evidence that any stressor, not just predation, which increases glucocorticoid concentrations will result in a decrease in reproductive output. [source] Small heat shock proteins, the cytoskeleton, and inclusion body formationNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2000M. W. Head Since first being implicated in central nervous system disease 10 years ago, much has been learned concerning the regulation and function of the small heat shock protein ,B-crystallin. Neuropathological, cellular and molecular studies all now point to a functional relationship between ,B-crystallin and intermediate filaments. ,B-crystallin accumulation marks reactive astrocytes in general in a wide variety of disorders and specifically intermediate filament-based glial inclusion bodies such as Rosenthal fibres found in astrocytes in Alexander's disease. In vitro, ,B-crystallin expression suppresses intermediate filament aggregation and can prevent or reverse experimentally induced glial inclusion body formation. Conversely, dysregulation of glial fibrillary acidic protein expression in vivo results in Rosenthal fibre formation and upregulation of endogenous ,B-crystallin expression. These data and those from studies recently carried out on other tissues strongly suggest that one function of this small heat shock protein is to modulate intermediate filament organization under conditions of physiological stress and neurodegenerative disease. [source] Lifetime sexual dimorphism in Juniperus communis var. communisPLANT SPECIES BIOLOGY, Issue 1 2007LENA K. WARD Abstract The sexes of dioecious Juniperus communis were differentially affected over their lifetime in response to ecological and physiological stress in populations of different ages studied over 23 years in southern England. In a young population, the female survival rate was less than the male rate, with more females dying during a severe attack by rabbits and later with fungus disease in the roots. The sex ratio (female : male) in marked individuals was predicted by age, changing from 1:1.13 in 1983 to 1:1.32 in 2005. In an old senescing population, where two-thirds of the individuals died, the sex ratio varied, but overall became more male biased (1:1.51,1:2.10). Males had a greater resistance to terminal disease, and were slightly older than females at death (110 years compared to 106). Young females grew less than males, presumably because of greater trade-offs with reproductive effort: the mean annual shoot growth was 6.7 cm compared to 8.1 cm in males. By approximately 30 years of age, heights of the sexes were significantly different. The annual growth of old females (4.8 cm) was greater than that in males (4.3 cm), possibly because males survived longer in poor health. Sexual differences in height in the old population were progressively lost. Cone abundance in females was less than that in males and cone production had greater periodicity; the young population outperformed the old. There were slightly longer time lags in inverse correlations between growth and reproductive indices in females. [source] Sex differentials in frailty in medieval EnglandAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010Sharon N. DeWitte Abstract In most modern populations, there are sex differentials in morbidity and mortality that favor women. This study addresses whether such female advantages existed to any appreciable degree in medieval Europe. The analyses presented here examine whether men and women with osteological stress markers faced the same risks of death in medieval London. The sample used for this study comes from the East Smithfield Black Death cemetery in London. The benefit of using this cemetery is that most, if not all, individuals interred in East Smithfield died from the same cause within a very short period of time. This allows for the analysis of the differences between men and women in the risks of mortality associated with osteological stress markers without the potential confounding effects of different causes of death. A sample of 299 adults (173 males, 126 females) from the East Smithfield cemetery was analyzed. The results indicate that the excess mortality associated with several osteological stress markers was higher for men than for women. This suggests that in this medieval population, previous physiological stress increased the risk of death for men during the Black Death to a greater extent than was true for women. Alternatively, the results might indicate that the Black Death discriminated less strongly between women with and without pre-existing health conditions than was true for men. These results are examined in light of previous analyses of East Smithfield and what is known about diet and sexually mediated access to resources in medieval England. Am J Phys Anthropol 143:285,297, 2010. © 2010 Wiley-Liss, Inc. [source] Ecological stress and linear enamel hypoplasia in CebusAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2010Madeleine B. Chollet Abstract Although it is assumed that monkeys in some environments experience more nutritional or physiological stress than others, little research has been conducted on this topic. This study examines the relationship between linear enamel hypoplasia (LEH) frequency, a physiological indicator of stress, and environmental stressors. To test this relationship, LEH frequencies were calculated for 144 Cebus from 54 locations in Brazil. Habitat, temperature range, and annual rainfall were compared between individuals with and without LEH. The LEH frequency for Cebus from semideciduous forests was significantly higher than that for monkeys from coastal areas, the rainforest, and the savanna (,2 = 9.97, df = 1; P = 0.0016). A significantly higher LEH frequency was also found for monkeys living in environments with the mean annual temperature between 15 and 18°C than for those in environments greater than 18°C (,2 = 7.74, df = 1, P = 0.0054). However, no significant difference was found between LEH frequency and annual rainfall (t = 1.22, P = 0.23) or the average difference in rainfall between the driest and wettest months (t = 0.77, P = 0.44). These results indicate that levels of physiological stress can differ among environments and that habitat and temperature, but not precipitation, may be driving the difference in stress levels among environments. Am J Phys Anthropol, 2010. © 2009 Wiley-Liss, Inc. [source] Markers of physiological stress in juvenile bonobos (Pan paniscus): Are enamel hypoplasia, skeletal development and tooth size interrelated?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009John R. Lukacs Abstract A reduction in enamel thickness due to disrupted amelogenesis is referred to as enamel hypoplasia (EH). Linear EH in permanent teeth is a widely accepted marker of systemic physiological stress. An enigmatic, nonlinear form of EH commonly manifest in great ape and human deciduous canines (dc) is known as localized hypoplasia of primary canines (LHPC). The etiology of LHPC and what it signifies,localized traumatic or systemic physiological stress,remains unclear. This report presents frequency data on LHPC, hypostotic cranial traits, and tooth size in a sample of juvenile bonobos, then tests hypotheses of intertrait association that improve knowledge of the etiology and meaning of LHPC. The fenestration hypothesis is tested using hypostotic cranial traits as a proxy for membrane bone ossification, and the relationship between tooth size, LHPC, and hypostosis is investigated. Macroscopic observations of EH, hypostotic traits, and measurements of buccolingual tooth size were conducted according to established standards. LHPC was found in 51.2% of bonobos (n = 86) and in 26% of dc teeth (n = 269). Hypostotic traits were observed in 55.2% of bonobos (n = 96). A test of the association between LHPC and hypostosis yielded nonsignificant results (,2 = 2.935; P = 0.0867). Primary canines were larger in specimens with LHPC than in unaffected specimens (paired samples t test; udc, P = 0.011; ldc, P = 0.018), a result consistent with the fenestration hypothesis of LHPC pathogenesis. Hypostosis was not associated with differences in tooth size (P > 0.05). LHPC may be an indirect indicator of physiological stress, resulting from large, buccally displaced primary canines. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Under restrictive conditions, can the widths of linear enamel hypoplasias be used as relative indicators of stress episode duration?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Amelia Hubbard Abstract Linear enamel hypoplasia (LEH), a type of enamel defect reflecting nonspecific physiological stress, has traditionally been used by bioarchaeologists to assess human health. Initially, measurements of defect width were used to estimate the duration of stress episodes. More recently, methods of counting within-defect perikymata (enamel growth increments) were developed to more accurately assess duration. Because perikymata are often not continuously visible within defects, while widths can usually be measured, the primary purpose of this article was to determine if, under restrictive conditions, the widths of LEH defects might be used as relative indicators of stress episode duration. Using a set of dental replicas from the prehistoric Irene Mound (1150,1400 A.D.), this study also investigated potential sources of variation in defect widths and how often defect widths could be measured and within-defect perikymata counted. Of 120 defects, only 47 contained both measurable defect widths and total within-defect perikymata, while 79 had measurable defect widths. Regression analysis revealed that, for these 47 defects, defect widths were more strongly related to the total number of within-defect perikymata than they were to crown region or tooth type. Although wide prediction intervals indicated that a defect's width could not be used to predict the number of within-defect perikymata for an individual, narrower confidence intervals associated with hypothetical mean population widths suggested that mean defect widths might be used to rank populations in terms of relative average stress episode duration. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source] Composite estimates of physiological stress, age, and diabetes in American SamoansAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2007Douglas E. Crews Abstract Composite estimates of physiological stress such as allostatic load (AL) were developed to help assess cumulative impacts of psychosocial and physical stressors on the body. Physiological responses to stress generally accelerate somatic wear-and-tear and chronic degenerative conditions (CDCs). Following McEwen (Neuropsychopharmacology 22 (1999) 108,124) and others, primary physiological mediators of somatic stress responses include glucocorticoids (cortisol), catecholamines (adrenaline and noradrenaline), and serum dihydroepiandosterone-sulfate (DHEA-S). Conversely, blood pressure (BP), serum HDL and total cholesterol, glycated hemoglobin (HbA1c), and waist/hip (w/h) ratio are modulated by such hormones, thereby acting as secondary mediators of stress response. When these risk factors are aggregated into a composite score, higher stress loads are associated with increased risks for days of school/work missed, functional losses, morbidity, and mortality in US samples. To examine stress loads in American Samoans, data on all 6 secondary mediators along with estimates of body habitus (i.e. height, weight, circumferences, skinfolds) and physiology (i.e. fasting insulin, LDLc, triglycerides, fasting glucose) were measured on 273 individuals residing on Tutuila Island in 1992. Four combinations of these physiological factors were used to determine composite estimates of stress. These were then assessed by sex for associations with age and the presence of diabetes. Composite estimates of stress load were higher in Samoan women than men. Associations with age tended to be low and negative in men, but positive in women, appearing to reflect cultural circumstances and population history. Stress load scores also were higher among those with diabetes than those without among both men and women. These results suggest that composite estimates of stress may be useful for assessing future risks of CDC's and the senescent processes that may underlie them in cross-cultural research. Am J Phys Anthropol, 2007. © 2007 Wiley-Liss, Inc. [source] Enamel hypoplasias and physiological stress in the Sima de los Huesos Middle Pleistocene homininsAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2004E. Cunha Abstract This study presents an analysis of linear enamel hypoplasias (LEH) and plane-form defects (PFD) in the hominine dental sample from the Sima de los Huesos (SH) Middle Pleistocene site in Atapuerca (Spain). The SH sample comprises 475 teeth, 467 permanent and 8 deciduous, belonging to a minimum of 28 individuals. The method for recording PFD and LEH is discussed, as well as the definition of LEH. The prevalence of LEH and PFD in SH permanent dentition (unilateral total count) is 4.6% (13/280). Only one deciduous tooth (lower dc) showed an enamel disruption. Prevalence by individual ranges from 18.7,30%. The most likely explanation for the relatively low LEH and PFD prevalence in the SH sample suggests that the SH population exhibited a low level of developmental stress. The age at occurrence of LEH and PFD was determined by counting the number of perikymata between each lesion and the cervix of the tooth. Assuming a periodicity of nine days for the incremental lines, the majority of LEH in the SH sample occurred during the third year of life and may be related to the metabolic stress associated with weaning. Am J Phys Anthropol 123:000,000, 2004. © 2004 Wiley-Liss, Inc. [source] Preliminary evidence of accumulation of stress during translocation in mantled howlersAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2010M.A. Socorro Aguilar-Cucurachi Abstract Translocation,an extensively used conservation tool,is a potentially stressful event, as animals are exposed to multiple stressors and cannot predict or control the changes in their environment. Therefore, it may be expected that during a translocation program stress accumulates and social behavior changes. Here, we present data from a translocation of four adult mantled howlers (Alouatta palliata), which was conducted in southern Veracruz (Mexico). We found that stress (measured in fecal corticosterone) increased during translocation, but that the rate of both affiliative and agonistic interactions remained unchanged. Females showed higher levels of corticosterone than males throughout translocation, although no sex differences were observed in social interactions. Our findings provide a preliminary evidence for accumulation of physiological stress during translocation in primates, and may have implications for decisions concerning releasing practices. Am. J. Primatol. 72:805,810, 2010.© 2010 Wiley-Liss, Inc. [source] Effects of habitat fragmentation and disturbance on howler monkeys: a reviewAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2010Víctor Arroyo-Rodríguez Abstract We examined the literature on the effects of habitat fragmentation and disturbance on howler monkeys (genus Alouatta) to (1) identify different threats that may affect howlers in fragmented landscapes; (2) review specific predictions developed in fragmentation theory and (3) identify the empirical evidence supporting these predictions. Although howlers are known for their ability to persist in both conserved and disturbed conditions, we found evidence that they are negatively affected by high levels of habitat loss, fragmentation and degradation. Patch size appears to be the main factor constraining populations in fragmented habitats, probably because patch size is positively related to food availability, and negatively related to anthropogenic pressures, physiological stress and parasite loads. Patch isolation is not a strong predictor of either patch occupancy or population size in howlers, a result that may be related to the ability of howlers to move among forest patches. Thus, we propose that it is probable that habitat loss has larger consistent negative effects on howler populations than habitat fragmentation per se. In general, food availability decreases with patch size, not only due to habitat loss, but also because the density of big trees, plant species richness and howlers' home range size are lower in smaller patches, where howlers' population densities are commonly higher. However, it is unclear which vegetation attributes have the biggest influence on howler populations. Similarly, our knowledge is still limited concerning the effects of postfragmentation threats (e.g. hunting and logging) on howlers living in forest patches, and how several endogenous threats (e.g. genetic diversity, physiological stress, and parasitism) affect the distribution, population structure and persistence of howlers. More long-term studies with comparable methods are necessary to quantify some of the patterns discussed in this review, and determine through meta-analyses whether there are significant inter-specific differences in species' responses to habitat loss and fragmentation. Am. J. Primatol. 72:1,16, 2010. © 2009 Wiley-Liss, Inc. [source] Cortisol reactions in five-year-olds to parent,child interaction: the moderating role of ego-resiliencyTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 7 2007Sanny Smeekens Background:, This study with five-year-olds is the first to examine whether low-quality interactions with parents elicit physiological stress in children beyond toddlerhood, as evident from elevated cortisol levels in their saliva. It was hypothesised that particularly children with low levels of ego-resiliency ,a personality construct reflecting the capacity to cope with stress , would show cortisol increases during low-quality parent,child interactions. Method:, In a sample of 101 five-year-old children (62 boys), parent,child interaction was observed at home during parent,child discourse that involved the recollection and discussion of emotional events that happened to the child in the past. Saliva samples to assess cortisol levels were collected before and 20 minutes after the parent,child discourse task. The children's teacher rated child ego-resiliency using a Dutch translation of the California Child Q-set (CCQ; Block & Block, 1980). Results:, One of the two parent,child interaction factors that emerged from a principal component analysis, namely negative parent,child interactions, was significantly related to the children's cortisol reaction; more negative parent,child interactions elicited significantly stronger cortisol reactions. The other parent,child interaction factor that was found, i.e., effective guidance, was not significantly related to children's cortisol reaction. As predicted, children low on ego-resiliency showed increases in cortisol during negative interactions with their parents, whereas high ego-resilient children did not. Conclusions:, The association between negative parent,child interactions and cortisol elevations in children may point to a likely mechanism through which negative parent,child interactions contribute to negative developmental outcomes as the repeated exposure to high levels of cortisol have earlier been found to negatively affect children's development and functioning in various areas. [source] The stability of the Arabidopsis transcriptome in transgenic plants expressing the marker genes nptII and uidATHE PLANT JOURNAL, Issue 6 2005Souad El Ouakfaoui Summary The ATH1 Arabidopsis GeneChip from Affymetrix was used to search for transcriptome changes in Arabidopsis associated with the strong expression of transgenes regulated by constitutive promoters. The insertion and expression of the commonly used marker genes, uidA and nptII, did not induce changes to the expression patterns of the approximately 24 000 genes that were screened under optimal growth conditions and under physiological stress imposed by low temperatures. Approximately 8000 genes (35% of the Arabidopsis genome) underwent changes in gene expression in both wild-type and transgenic plants under abiotic stresses such as salt, dehydration, cold, and heat. This study provides detailed information on the extent of non-targeted or pleiotropic effects of transgenes on plants and shows that the transgenic and non-transgenic plants were equivalent in their global patterns of transcription. This information may help to extend our understanding and interpretation of the principle of substantial equivalence which is used as a first step in the biosafety evaluation of transgenic crops. [source] Performance evaluation of concurrent rice,fish,prawn culture with and without cull harvestingAQUACULTURE RESEARCH, Issue 9 2010Rajeeb K Mohanty Abstract This study was carried out in farmers' fields for three experimental culture cycles to evaluate the performance of rice,fish,prawn culture. The treatments carried out were deepwater rice mono-cropping (R), and rice,fish,prawn culture with cull harvesting (R,FC) and without cull harvesting (R,F). Water pH and total alkalinity were significantly higher (P<0.05) in R,FC than in R,F, while the concentrations of total suspended solids, plankton and chlorophyll a were higher in R,F. Cull harvesting in R,FC had no marked influence on the concentrations of dissolved oxygen, NH4+, nitrite, nitrate and phosphate compared with the R,F treatment. The significantly higher fish and prawn yields (P<0.05) and species-wise faster individual growth performance in R,FC than in R,F were probably due to periodic cull harvesting, which minimized the competition for food and space as well as physiological stress at reduced density. The paddy yield and percentage increase in paddy yield over rice mono-crop was significantly higher (P<0.05) in R,FC (25%), followed by R,F (16.9%), probably due to lower chlorophyll a (36.7 mg m,3) and plankton density (1.4 × 104 L,1), which minimized the competition for nutrients with rice plants. The highest rice equivalent yield (38.5), output value,cultivation cost ratio (1.56) and enhanced net return (28%) in deepwater rice,fish culture were recorded when cull harvesting was practiced. [source] Transposable elements and an epigenetic basis for punctuated equilibriaBIOESSAYS, Issue 7 2009David W. Zeh Abstract Evolution is frequently concentrated in bursts of rapid morphological change and speciation followed by long-term stasis. We propose that this pattern of punctuated equilibria results from an evolutionary tug-of-war between host genomes and transposable elements (TEs) mediated through the epigenome. According to this hypothesis, epigenetic regulatory mechanisms (RNA interference, DNA methylation and histone modifications) maintain stasis by suppressing TE mobilization. However, physiological stress, induced by climate change or invasion of new habitats, disrupts epigenetic regulation and unleashes TEs. With their capacity to drive non-adaptive host evolution, mobilized TEs can restructure the genome and displace populations from adaptive peaks, thus providing an escape from stasis and generating genetic innovations required for rapid diversification. This "epi-transposon hypothesis" can not only explain macroevolutionary tempo and mode, but may also resolve other long-standing controversies, such as Wright's shifting balance theory, Mayr's peripheral isolates model, and McClintock's view of genome restructuring as an adaptive response to challenge. [source] The effect of heating rate on Escherichia coli metabolism, physiological stress, transcriptional response, and production of temperature-induced recombinant protein: A scale-down studyBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009Luis Caspeta Abstract At the laboratory scale, sudden step increases from 30 to 42°C can be readily accomplished when expressing heterologous proteins in heat-inducible systems. However, for large scale-cultures only slow ramp-type increases in temperature are possible due to heat transfer limitations, where the heating rate decreases as the scale increases. In this work, the transcriptional and metabolic responses of a recombinant Escherichia coli strain to temperature-induced synthesis of pre-proinsulin in high cell density cultures were examined at different heating rates. Heating rates of 6, 1.7, 0.8, and 0.4°C/min were tested in a scale-down approach to mimic fermentors of 0.1, 5, 20, and 100 m3, respectively. The highest yield and concentration of recombinant protein was obtained for the slowest heating rate. As the heating rate increased, the yield and maximum recombinant protein concentration decreased, whereas a larger fraction of carbon skeletons was lost as acetate, lactate, and formate. Compared to 30°C, the mRNA levels of selected heat-shock genes at 38 and 42°C, as quantified by qRT-PCR, increased between 2- to over 42-fold when cultures were induced at 6, 1.7, and 0.8°C/min, but no increase was observed at 0.4°C/min. Only small increases (between 1.5- and 4-fold) in the expression of the stress genes spoT and relA were observed at 42°C for cultures induced at 1.7 and 6°C/min, suggesting that cells subjected to slow temperature increases can adapt to stress. mRNA levels of genes from the transcription,translation machinery (tufB, rpoA, and tig) decreased between 40% and 80% at 6, 1.7 and 0.8°C/min, whereas a transient increase occurred for 0.4°C/min at 42°C. mRNA levels of the gene coding for pre-proinsulin showed a similar profile to transcripts of heat-shock genes, reflecting a probable analogous induction mechanism. Altogether, the results obtained indicate that slow heating rates, such as those likely to occur in conventional large-scale fermentors, favored heterologous protein synthesis by the thermo-inducible expression system used in this report. Knowledge of the effect of heating rate on bacterial physiology and product formation is useful for the rational design of scale-down and scale-up strategies and optimum recombinant protein induction schemes. Biotechnol. Bioeng. 2009;102: 468,482. © 2008 Wiley Periodicals, Inc. [source] | |||||||||||||||||||||||||||||||