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Sample records for linking species physiology

  1. Mechanistic species distribution modelling as a link between physiology and conservation

    PubMed Central

    Evans, Tyler G.; Diamond, Sarah E.; Kelly, Morgan W.

    2015-01-01

    Climate change conservation planning relies heavily on correlative species distribution models that estimate future areas of occupancy based on environmental conditions encountered in present-day ranges. The approach benefits from rapid assessment of vulnerability over a large number of organisms, but can have poor predictive power when transposed to novel environments and reveals little in the way of causal mechanisms that define changes in species distribution or abundance. Having conservation planning rely largely on this single approach also increases the risk of policy failure. Mechanistic models that are parameterized with physiological information are expected to be more robust when extrapolating distributions to future environmental conditions and can identify physiological processes that set range boundaries. Implementation of mechanistic species distribution models requires knowledge of how environmental change influences physiological performance, and because this information is currently restricted to a comparatively small number of well-studied organisms, use of mechanistic modelling in the context of climate change conservation is limited. In this review, we propose that the need to develop mechanistic models that incorporate physiological data presents an opportunity for physiologists to contribute more directly to climate change conservation and advance the field of conservation physiology. We begin by describing the prevalence of species distribution modelling in climate change conservation, highlighting the benefits and drawbacks of both mechanistic and correlative approaches. Next, we emphasize the need to expand mechanistic models and discuss potential metrics of physiological performance suitable for integration into mechanistic models. We conclude by summarizing other factors, such as the need to consider demography, limiting broader application of mechanistic models in climate change conservation. Ideally, modellers, physiologists and

  2. Mechanistic species distribution modelling as a link between physiology and conservation.

    PubMed

    Evans, Tyler G; Diamond, Sarah E; Kelly, Morgan W

    2015-01-01

    Climate change conservation planning relies heavily on correlative species distribution models that estimate future areas of occupancy based on environmental conditions encountered in present-day ranges. The approach benefits from rapid assessment of vulnerability over a large number of organisms, but can have poor predictive power when transposed to novel environments and reveals little in the way of causal mechanisms that define changes in species distribution or abundance. Having conservation planning rely largely on this single approach also increases the risk of policy failure. Mechanistic models that are parameterized with physiological information are expected to be more robust when extrapolating distributions to future environmental conditions and can identify physiological processes that set range boundaries. Implementation of mechanistic species distribution models requires knowledge of how environmental change influences physiological performance, and because this information is currently restricted to a comparatively small number of well-studied organisms, use of mechanistic modelling in the context of climate change conservation is limited. In this review, we propose that the need to develop mechanistic models that incorporate physiological data presents an opportunity for physiologists to contribute more directly to climate change conservation and advance the field of conservation physiology. We begin by describing the prevalence of species distribution modelling in climate change conservation, highlighting the benefits and drawbacks of both mechanistic and correlative approaches. Next, we emphasize the need to expand mechanistic models and discuss potential metrics of physiological performance suitable for integration into mechanistic models. We conclude by summarizing other factors, such as the need to consider demography, limiting broader application of mechanistic models in climate change conservation. Ideally, modellers, physiologists and

  3. Remote sensing of fire severity: linking post-fire reflectance data with physiological responses in two western conifer species

    NASA Astrophysics Data System (ADS)

    Sparks, A. M.; Smith, A. M.; Kolden, C.; Apostol, K. G.; Boschetti, L.

    2014-12-01

    Fire is a common disturbance in forested ecosystems in the western U.S. and can be responsible for long-term impacts on vegetation and soil. An improved understanding of how ecosystems recover after fire is necessary so that land managers can plan for and mitigate the effects of these disturbances. Although several studies have attempted to link fire intensity with severity, direct links between spectral indices of severity and key physiological changes in vegetation are not well understood. We conducted an assessment of how two western conifer species respond to four fire radiative energy treatments, with spectra acquired pre- and up to a month post-burn. After transforming the spectral data into Landsat 8 equivalent reflectance, burn severity indices commonly used in the remote sensing community were compared to concurrent physiological measurements including gas exchange and photosynthetic rate. Preliminary results indicate significant relationships between several fire severity indices and physiological responses measured in the conifer seedlings.

  4. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    NASA Astrophysics Data System (ADS)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  5. No evidence for parasitism-linked changes in immune function or oxidative physiology over the annual cycle of an avian species.

    PubMed

    Pap, Péter L; Sesarman, Alina; Vágási, Csongor I; Buehler, Deborah M; Pătraş, Laura; Versteegh, Maaike A; Banciu, Manuela

    2014-01-01

    Temporally changing environmental conditions occur in most parts of the world and can exert strong pressure on the immune defense of organisms. Seasonality may result in changes in physiological traits over the year, and such changes may be essential for the optimization of defense against infections. Evidence from field and laboratory studies suggest the existence of links between environmental conditions, such as infection risk, and the ability of animals to mount an immune response or to overcome infections; however, the importance of parasites in mediating seasonal change in immune defense is still debated. In this study, we test the hypothesis that seasonal change in immune function and connected physiological traits is related to parasite infection. We sampled captive house sparrows (Passer domesticus) once every 2 mo over 14 mo and compared the annual variation in 12 measures of condition, immune function, antioxidant status, and oxidative damage among birds naturally infested with coccidians or medicated against these parasites. We found significant variation in 10 of 12 traits over the year. However, we found little support for parasite-mediated change in immune function and oxidative status in captive house sparrows. Of the 12 measures, only one was slightly affected by parasite treatment. In support of the absence of any effect of coccidians on the annual profile of the condition and physiological traits, we found no consistent relationships between the intensity of infestation and these response variables over the year. Our results show that chronic coccidian infections have limited effect on the seasonal changing of physiological traits and that the patterns of these measures are probably more affected by acute infection and/or virulent parasite strains. PMID:25244384

  6. Evidence that the negative relationship between seed mass and relative growth rate is not physiological but linked to species identity: a within-family analysis of Scots pine.

    PubMed

    Castro, Jorge; Reich, Peter B; Sánchez-Miranda, Angela; Guerrero, Juan D

    2008-07-01

    Seed mass and relative growth rate (RGR) are important determinants of early seedling growth, and hence seedling establishment. Although a positive interspecific relationship between seed mass and seedling dry mass is well established, much less is known about the relationships among seed mass, seedling mass and RGR within species. We examined relationships among seed mass, seedling mass and RGR within and among maternal plant lines of Scots pine (Pinus sylvestris L.). To assess the effects of seed mass and maternal origin on RGR, individual seeds from two seed crops (years 2004 and 2005) of ten maternal plants growing under nursery conditions were weighed and then germinated. Seed mass was strongly determined by maternal plant, and seedling mass was largely determined by seed mass, with a positive correlation between these variables both across and within maternal plants. In contrast, RGR was weakly related to seed mass, with no consistent pattern in the sign of the relationship. It is well known that species differ in RGR and that RGR is related to seed mass across species. Lack of consistent evidence for this relationship within maternal lines, and for Scots pine overall, suggests that the relationship is not directly causal, but reflects consistent evolutionary covariation in these two physiologically independent traits. PMID:18450572

  7. Linking the Salt Transcriptome with Physiological Responses of a Salt-Resistant Populus Species as a Strategy to Identify Genes Important for Stress Acclimation1[W][OA

    PubMed Central

    Brinker, Monika; Brosché, Mikael; Vinocur, Basia; Abo-Ogiala, Atef; Fayyaz, Payam; Janz, Dennis; Ottow, Eric A.; Cullmann, Andreas D.; Saborowski, Joachim; Kangasjärvi, Jaakko; Altman, Arie; Polle, Andrea

    2010-01-01

    To investigate early salt acclimation mechanisms in a salt-tolerant poplar species (Populus euphratica), the kinetics of molecular, metabolic, and physiological changes during a 24-h salt exposure were measured. Three distinct phases of salt stress were identified by analyses of the osmotic pressure and the shoot water potential: dehydration, salt accumulation, and osmotic restoration associated with ionic stress. The duration and intensity of these phases differed between leaves and roots. Transcriptome analysis using P. euphratica-specific microarrays revealed clusters of coexpressed genes in these phases, with only 3% overlapping salt-responsive genes in leaves and roots. Acclimation of cellular metabolism to high salt concentrations involved remodeling of amino acid and protein biosynthesis and increased expression of molecular chaperones (dehydrins, osmotin). Leaves suffered initially from dehydration, which resulted in changes in transcript levels of mitochondrial and photosynthetic genes, indicating adjustment of energy metabolism. Initially, decreases in stress-related genes were found, whereas increases occurred only when leaves had restored the osmotic balance by salt accumulation. Comparative in silico analysis of the poplar stress regulon with Arabidopsis (Arabidopsis thaliana) orthologs was used as a strategy to reduce the number of candidate genes for functional analysis. Analysis of Arabidopsis knockout lines identified a lipocalin-like gene (AtTIL) and a gene encoding a protein with previously unknown functions (AtSIS) to play roles in salt tolerance. In conclusion, by dissecting the stress transcriptome of tolerant species, novel genes important for salt endurance can be identified. PMID:20959419

  8. Remapping Attention Pointers: Linking Physiology and Behavior.

    PubMed

    Rolfs, Martin; Szinte, Martin

    2016-06-01

    Our eyes rapidly scan visual scenes, displacing the projection on the retina with every move. Yet these frequent retinal image shifts do not appear to hamper vision. Two recent physiological studies shed new light on the role of attention in visual processing across saccadic eye movements. PMID:27118641

  9. The physiology of global change: linking patterns to mechanisms.

    PubMed

    Somero, George N

    2012-01-01

    Global change includes alterations in ocean temperature, oxygen availability, salinity, and pH, abiotic variables with strong and interacting influences on the physiology of all taxa. Physiological stresses resulting from changes in these four variables may cause broad biogeographic shifts as well as localized changes in distribution in mosaic habitats. To elucidate these causal linkages, I address the following questions: What types of physiological limitations can alter species' distributions and, in cases of extreme stress, cause extinctions? Which species are most threatened by these physiological challenges--and why? How do contents of genomes establish capacities to respond to global change, notably in the case of species that have evolved in highly stable habitats? How fully can phenotypic acclimatization offset abiotic stress? Can physiological measurements, including new molecular ("-omic") approaches, provide indices of the degree of sublethal stress an organism experiences? And can physiological evolution keep pace with global change? PMID:22457968

  10. Linking adult hippocampal neurogenesis with human physiology and disease.

    PubMed

    Bowers, Megan; Jessberger, Sebastian

    2016-07-01

    We here review the existing evidence linking adult hippocampal neurogenesis and human brain function in physiology and disease. Furthermore, we aim to point out where evidence is missing, highlight current promising avenues of investigation, and suggest future tools and approaches to foster the link between life-long neurogenesis and human brain function. Developmental Dynamics 245:702-709, 2016. © 2016 Wiley Periodicals, Inc. PMID:26890418

  11. Biological causal links on physiological and evolutionary time scales.

    PubMed

    Karmon, Amit; Pilpel, Yitzhak

    2016-01-01

    Correlation does not imply causation. If two variables, say A and B, are correlated, it could be because A causes B, or that B causes A, or because a third factor affects them both. We suggest that in many cases in biology, the causal link might be bi-directional: A causes B through a fast-acting physiological process, while B causes A through a slowly accumulating evolutionary process. Furthermore, many trained biologists tend to consistently focus at first on the fast-acting direction, and overlook the slower process in the opposite direction. We analyse several examples from modern biology that demonstrate this bias (codon usage optimality and gene expression, gene duplication and genetic dispensability, stem cell division and cancer risk, and the microbiome and host metabolism) and also discuss an example from linguistics. These examples demonstrate mutual effects between the fast physiological processes and the slow evolutionary ones. We believe that building awareness of inference biases among biologists who tend to prefer one causal direction over another could improve scientific reasoning. PMID:27113916

  12. Biological causal links on physiological and evolutionary time scales

    PubMed Central

    Karmon, Amit; Pilpel, Yitzhak

    2016-01-01

    Correlation does not imply causation. If two variables, say A and B, are correlated, it could be because A causes B, or that B causes A, or because a third factor affects them both. We suggest that in many cases in biology, the causal link might be bi-directional: A causes B through a fast-acting physiological process, while B causes A through a slowly accumulating evolutionary process. Furthermore, many trained biologists tend to consistently focus at first on the fast-acting direction, and overlook the slower process in the opposite direction. We analyse several examples from modern biology that demonstrate this bias (codon usage optimality and gene expression, gene duplication and genetic dispensability, stem cell division and cancer risk, and the microbiome and host metabolism) and also discuss an example from linguistics. These examples demonstrate mutual effects between the fast physiological processes and the slow evolutionary ones. We believe that building awareness of inference biases among biologists who tend to prefer one causal direction over another could improve scientific reasoning. PMID:27113916

  13. The role thermal physiology plays in species invasion

    PubMed Central

    Kelley, Amanda L.

    2014-01-01

    The characterization of physiological phenotypes that may play a part in the establishment of non-native species can broaden our understanding about the ecology of species invasion. Here, an assessment was carried out by comparing the responses of invasive and native species to thermal stress. The goal was to identify physiological patterns that facilitate invasion success and to investigate whether these traits are widespread among invasive ectotherms. Four hypotheses were generated and tested using a review of the literature to determine whether they could be supported across taxonomically diverse invasive organisms. The four hypotheses are as follows: (i) broad geographical temperature tolerances (thermal width) confer a higher upper thermal tolerance threshold for invasive rather than native species; (ii) the upper thermal extreme experienced in nature is more highly correlated with upper thermal tolerance threshold for invasive vs. native animals; (iii) protein chaperone expression—a cellular mechanism that underlies an organism's thermal tolerance threshold—is greater in invasive organisms than in native ones; and (iv) acclimation to higher temperatures can promote a greater range of thermal tolerance for invasive compared with native species. Each hypothesis was supported by a meta-analysis of the invasive/thermal physiology literature, providing further evidence that physiology plays a substantial role in the establishment of invasive ectotherms. PMID:27293666

  14. Exploring the Physiological Link between Psoriasis and Mood Disorders

    PubMed Central

    Connor, Cody J.; Liu, Vincent; Fiedorowicz, Jess G.

    2015-01-01

    Psoriasis is a chronic, immune-mediated skin condition with a high rate of psychiatric comorbidity, which often goes unrecognized. Beyond the negative consequences of mood disorders like depression and anxiety on patient quality of life, evidence suggests that these conditions can worsen the severity of psoriatic disease. The mechanisms behind this relationship are not entirely understood, but inflammation seems to be a key feature linking psoriasis with mood disorders, and physiologic modulators of this inflammation, including the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, demonstrate changes with psychopathology that may be contributory. Cyclical disruptions in the secretion of the sleep hormone, melatonin, are also observed in both depression and psoriasis, and with well-recognized anti-inflammatory and antioxidant activity, this aberration may represent a shared contributor to both conditions as well as common comorbidities like diabetes and cardiovascular disease. While understanding the complexities of the biological mechanisms at play will be key in optimizing the management of patients with comorbid psoriasis and depression/anxiety, one thing is certain: recognition of psychiatric comorbidity is an imperative first step in effectively treating these patients as a whole. Evidence that improvement in mood decreases psoriasis severity underscores how psychological awareness can be critical to clinicians in their practice. PMID:26550011

  15. Exploring the Physiological Link between Psoriasis and Mood Disorders.

    PubMed

    Connor, Cody J; Liu, Vincent; Fiedorowicz, Jess G

    2015-01-01

    Psoriasis is a chronic, immune-mediated skin condition with a high rate of psychiatric comorbidity, which often goes unrecognized. Beyond the negative consequences of mood disorders like depression and anxiety on patient quality of life, evidence suggests that these conditions can worsen the severity of psoriatic disease. The mechanisms behind this relationship are not entirely understood, but inflammation seems to be a key feature linking psoriasis with mood disorders, and physiologic modulators of this inflammation, including the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, demonstrate changes with psychopathology that may be contributory. Cyclical disruptions in the secretion of the sleep hormone, melatonin, are also observed in both depression and psoriasis, and with well-recognized anti-inflammatory and antioxidant activity, this aberration may represent a shared contributor to both conditions as well as common comorbidities like diabetes and cardiovascular disease. While understanding the complexities of the biological mechanisms at play will be key in optimizing the management of patients with comorbid psoriasis and depression/anxiety, one thing is certain: recognition of psychiatric comorbidity is an imperative first step in effectively treating these patients as a whole. Evidence that improvement in mood decreases psoriasis severity underscores how psychological awareness can be critical to clinicians in their practice. PMID:26550011

  16. Ocean warming and acidification: Unifying physiological principles linking organism response to ecosystem change?

    NASA Astrophysics Data System (ADS)

    Pörtner, H. O.; Bock, C.; Lannig, G.; Lucassen, M.; Mark, F. C.; Stark, A.; Walther, K.; Wittmann, A.

    2011-12-01

    The effects of ocean warming and acidification on individual species of marine ectothermic animals may be based on some common denominators, i.e. physiological responses that can be assumed to reflect unifying principles, common to all marine animal phyla. Identification of these principles requires studies, which reach beyond the species-specific response, and consider multiple stressors, for example temperature, CO2 or extreme hypoxia. Analyses of response and acclimation include functional traits of physiological performance on various levels of biological organisation, from changes in the transcriptome to patterns of acid-base regulation and whole animal thermal tolerance. Conclusions are substantiated by comparisons of species and phyla from temperate, Arctic and Antarctic ecosystems and also benefit from the interpretation of paleo-patterns based on the use of a unifying physiological concept, suitable to integrate relevant environmental factors into a more comprehensive picture. Studying the differential specialization of animals on climate regimes and their sensitivity to climate leads to improved understanding of ongoing and past ecosystem change and should then support more reliable projections of future scenarios. For example, accumulating CO2 causes disturbances in acid-base status. Resilience to ocean acidification may be reflected in the capacity to compensate for these disturbances or their secondary effects. Ion and pH regulation comprise thermally sensitive active and passive transfer processes across membranes. Specific responses of ion transporter genes and their products to temperature and CO2 were found in fish, crustaceans and bivalves. However, compensation may cause unfavourable shifts in energy budget and beyond that hamper cellular and mitochondrial metabolism, which are directly linked to the animal's aerobic performance window. In crabs, oysters and, possibly, fishes, a narrowing of the thermal window is caused by moderate increases in

  17. Physiological characteristics of mercury uptake by two estuarine species

    USGS Publications Warehouse

    Luoma, S.N.

    1977-01-01

    Rapid uptake and slow loss of Hg will result from short exposures of some organisms to this metal, due to the transformation of Hg to a slowly exchanging form within the organisms. The extent of the difference between exposure time and depuration time will depend upon the rate of transformation during uptake. For the polychaete worm Neanthes succinea and the shrimp Palaemon debilis such transformations are extremely rapid. The exchange of Hg from the slowly exchanging compartment is similar among a wide variety of species. Thus, interspecies differences in susceptibility to Hg may be determined by differences in biochemical transformation rates and physiological permeability to the metal. ?? 1977 Springer-Verlag.

  18. Xanthine Oxidoreductase-Derived Reactive Species: Physiological and Pathological Effects

    PubMed Central

    Bortolotti, Massimo

    2016-01-01

    Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid and is widely distributed among species. In addition to this housekeeping function, mammalian XOR is a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various pathways. This review intends to address the physiological and pathological roles of XOR-derived oxidant molecules. The cytocidal action of XOR products has been claimed in relation to tissue damage, in particular damage induced by hypoxia and ischemia. Attempts to exploit this activity to eliminate unwanted cells via the construction of conjugates have also been reported. Moreover, different aspects of XOR activity related to phlogosis, endothelial activation, leukocyte activation, and vascular tone regulation, have been taken into consideration. Finally, the positive and negative outcomes concerning cancer pathology have been analyzed because XOR products may induce mutagenesis, cell proliferation, and tumor progression, but they are also associated with apoptosis and cell differentiation. In conclusion, XOR activity generates free radicals and other oxidant reactive species that may result in either harmful or beneficial outcomes. PMID:26823950

  19. Xanthine Oxidoreductase-Derived Reactive Species: Physiological and Pathological Effects.

    PubMed

    Battelli, Maria Giulia; Polito, Letizia; Bortolotti, Massimo; Bolognesi, Andrea

    2016-01-01

    Xanthine oxidoreductase (XOR) is the enzyme that catalyzes the oxidation of hypoxanthine to xanthine and xanthine to uric acid and is widely distributed among species. In addition to this housekeeping function, mammalian XOR is a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various pathways. This review intends to address the physiological and pathological roles of XOR-derived oxidant molecules. The cytocidal action of XOR products has been claimed in relation to tissue damage, in particular damage induced by hypoxia and ischemia. Attempts to exploit this activity to eliminate unwanted cells via the construction of conjugates have also been reported. Moreover, different aspects of XOR activity related to phlogosis, endothelial activation, leukocyte activation, and vascular tone regulation, have been taken into consideration. Finally, the positive and negative outcomes concerning cancer pathology have been analyzed because XOR products may induce mutagenesis, cell proliferation, and tumor progression, but they are also associated with apoptosis and cell differentiation. In conclusion, XOR activity generates free radicals and other oxidant reactive species that may result in either harmful or beneficial outcomes. PMID:26823950

  20. Circadian Dysrhythmias, Physiological Aberrations, and the Link to Skin Cancer

    PubMed Central

    Gutierrez, Daniel; Arbesman, Joshua

    2016-01-01

    Circadian rhythms are core regulators of a variety of mammalian physiologic processes and oscillate in a 24-h pattern. Many peripheral organs possess endogenous rhythmicity that is then modulated by a master clock; the skin is one of these peripheral organs. The dysregulation of rhythms is associated with decreased ability to ameliorate cellular stressors at a local and global level, which then increases the propensity for the development of neoplastic growths. In this article, we review the implications of altered circadian rhythms on DNA repair as well as modified gene expression of core clock proteins with particular focus on skin models. These findings are then correlated with epidemiologic data regarding skin cancer to showcase the effects of circadian disruption on this phenomenon. PMID:27128901

  1. Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity

    PubMed Central

    Beckhauser, Thiago Fernando; Francis-Oliveira, José; De Pasquale, Roberto

    2016-01-01

    In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated. PMID:27625575

  2. Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity.

    PubMed

    Beckhauser, Thiago Fernando; Francis-Oliveira, José; De Pasquale, Roberto

    2016-01-01

    In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated. PMID:27625575

  3. Linking vegetation structure, function and physiology through spectroscopic remote sensing

    NASA Astrophysics Data System (ADS)

    Serbin, S.; Singh, A.; Couture, J. J.; Shiklomanov, A. N.; Rogers, A.; Desai, A. R.; Kruger, E. L.; Townsend, P. A.

    2015-12-01

    Terrestrial ecosystem process models require detailed information on ecosystem states and canopy properties to properly simulate the fluxes of carbon (C), water and energy from the land to the atmosphere and assess the vulnerability of ecosystems to perturbations. Current models fail to adequately capture the magnitude, spatial variation, and seasonality of terrestrial C uptake and storage, leading to significant uncertainties in the size and fate of the terrestrial C sink. By and large, these parameter and process uncertainties arise from inadequate spatial and temporal representation of plant traits, vegetation structure, and functioning. With increases in computational power and changes to model architecture and approaches, it is now possible for models to leverage detailed, data rich and spatially explicit descriptions of ecosystems to inform parameter distributions and trait tradeoffs. In this regard, spectroscopy and imaging spectroscopy data have been shown to be invaluable observational datasets to capture broad-scale spatial and, eventually, temporal dynamics in important vegetation properties. We illustrate the linkage of plant traits and spectral observations to supply key data constraints for model parameterization. These constraints can come either in the form of the raw spectroscopic data (reflectance, absorbtance) or physiological traits derived from spectroscopy. In this presentation we highlight our ongoing work to build ecological scaling relationships between critical vegetation characteristics and optical properties across diverse and complex canopies, including temperate broadleaf and conifer forests, Mediterranean vegetation, Arctic systems, and agriculture. We focus on work at the leaf, stand, and landscape scales, illustrating the importance of capturing the underlying variability in a range of parameters (including vertical variation within canopies) to enable more efficient scaling of traits related to functional diversity of ecosystems.

  4. Population structure, physiology and ecohydrological impacts of dioecious riparian tree species of western North America.

    PubMed

    Hultine, K R; Bush, S E; West, A G; Ehleringer, J R

    2007-11-01

    The global water cycle is intimately linked to vegetation structure and function. Nowhere is this more apparent than in the arid west where riparian forests serve as ribbons of productivity in otherwise mostly unproductive landscapes. Dioecy is common among tree species that make up western North American riparian forests. There are intrinsic physiological differences between male and female dioecious riparian trees that may influence population structure (i.e., the ratio of male to female trees) and impact ecohydrology at large scales. In this paper, we review the current literature on sex ratio patterns and physiology of dioecious riparian tree species. Then develop a conceptual framework of the mechanisms that underlie population structure of dominant riparian tree species. Finally, we identify linkages between population structure and ecohydrological processes such as evapotranspiration and streamflow. A more thorough understanding of the mechanisms that underlie population structure of dominant riparian tree species will enable us to better predict global change impacts on vegetation and water cycling at multiple scales. PMID:17665219

  5. Physiological Differentiation within a Single-Species Biofilm Fueled by Serpentinization

    PubMed Central

    Brazelton, William J.; Mehta, Mausmi P.; Kelley, Deborah S.; Baross, John A.

    2011-01-01

    ABSTRACT Carbonate chimneys at the Lost City hydrothermal field are coated in biofilms dominated by a single phylotype of archaea known as Lost City Methanosarcinales. In this study, we have detected surprising physiological complexity in single-species biofilms, which is typically indicative of multispecies biofilm communities. Multiple cell morphologies were visible within the biofilms by transmission electron microscopy, and some cells contained intracellular membranes that may facilitate methane oxidation. Both methane production and oxidation were detected at 70 to 80°C and pH 9 to 10 in samples containing the single-species biofilms. Both processes were stimulated by the presence of hydrogen (H2), indicating that methane production and oxidation are part of a syntrophic interaction. Metagenomic data included a sequence encoding AMP-forming acetyl coenzyme A synthetase, indicating that acetate may play a role in the methane-cycling syntrophy. A wide range of nitrogen fixation genes were also identified, many of which were likely acquired via lateral gene transfer (LGT). Our results indicate that cells within these single-species biofilms may have differentiated into multiple physiological roles to form multicellular communities linked by metabolic interactions and LGT. Communities similar to these Lost City biofilms are likely to have existed early in the evolution of life, and we discuss how the multicellular characteristics of ancient hydrogen-fueled biofilm communities could have stimulated ecological diversification, as well as unity of biochemistry, during the earliest stages of cellular evolution. PMID:21791580

  6. Integrating physiological threshold experiments with climate modeling to project mangrove species' range expansion.

    PubMed

    Cavanaugh, Kyle C; Parker, John D; Cook-Patton, Susan C; Feller, Ilka C; Williams, A Park; Kellner, James R

    2015-05-01

    Predictions of climate-related shifts in species ranges have largely been based on correlative models. Due to limitations of these models, there is a need for more integration of experimental approaches when studying impacts of climate change on species distributions. Here, we used controlled experiments to identify physiological thresholds that control poleward range limits of three species of mangroves found in North America. We found that all three species exhibited a threshold response to extreme cold, but freeze tolerance thresholds varied among species. From these experiments, we developed a climate metric, freeze degree days (FDD), which incorporates both the intensity and the frequency of freezes. When included in distribution models, FDD accurately predicted mangrove presence/absence. Using 28 years of satellite imagery, we linked FDD to observed changes in mangrove abundance in Florida, further exemplifying the importance of extreme cold. We then used downscaled climate projections of FDD to project that these range limits will move northward by 2.2-3.2 km yr(-1) over the next 50 years. PMID:25558057

  7. Principles for integrating reactive species into in vivo biological processes: Examples from exercise physiology.

    PubMed

    Margaritelis, Nikos V; Cobley, James N; Paschalis, Vassilis; Veskoukis, Aristidis S; Theodorou, Anastasios A; Kyparos, Antonios; Nikolaidis, Michalis G

    2016-04-01

    The equivocal role of reactive species and redox signaling in exercise responses and adaptations is an example clearly showing the inadequacy of current redox biology research to shed light on fundamental biological processes in vivo. Part of the answer probably relies on the extreme complexity of the in vivo redox biology and the limitations of the currently applied methodological and experimental tools. We propose six fundamental principles that should be considered in future studies to mechanistically link reactive species production to exercise responses or adaptations: 1) identify and quantify the reactive species, 2) determine the potential signaling properties of the reactive species, 3) detect the sources of reactive species, 4) locate the domain modified and verify the (ir)reversibility of post-translational modifications, 5) establish causality between redox and physiological measurements, 6) use selective and targeted antioxidants. Fulfilling these principles requires an idealized human experimental setting, which is certainly a utopia. Thus, researchers should choose to satisfy those principles, which, based on scientific evidence, are most critical for their specific research question. PMID:26721187

  8. The AquaDEB project (phase I): Analysing the physiological flexibility of aquatic species and connecting physiological diversity to ecological and evolutionary processes by using Dynamic Energy Budgets

    NASA Astrophysics Data System (ADS)

    Alunno-Bruscia, Marianne; van der Veer, Henk W.; Kooijman, Sebastiaan A. L. M.

    2009-08-01

    The European Research Project AquaDEB (2007-2011, http://www.ifremer.fr/aquadeb/) is joining skills and expertise of some French and Dutch research institutes and universities to analyse the physiological flexibility of aquatic organisms and to link it to ecological and evolutionary processes within a common theoretical framework for quantitative bioenergetics [Kooijman, S.A.L.M., 2000. Dynamic energy and mass budgets in biological systems. Cambridge University Press, Cambridge]. The main scientific objectives in AquaDEB are i) to study and compare the sensitivity of aquatic species (mainly molluscs and fish) to environmental variability of natural or human origin, and ii) to evaluate the related consequences at different biological levels (individual, population, ecosystem) and temporal scales (life cycle, population dynamics, evolution). At mid-term life, the AquaDEB collaboration has already yielded interesting results by quantifying bio-energetic processes of various aquatic species (e.g. molluscs, fish, crustaceans, algae) with a single mathematical framework. It has also allowed to federate scientists with different backgrounds, e.g. mathematics, microbiology, ecology, chemistry, and working in different fields, e.g. aquaculture, fisheries, ecology, agronomy, ecotoxicology, climate change. For the two coming years, the focus of the AquaDEB collaboration will be in priority: (i) to compare energetic and physiological strategies among species through the DEB parameter values and to identify the factors responsible for any differences in bioenergetics and physiology; and to compare dynamic (DEB) versus static (SEB) energy models to study the physiological performance of aquatic species; (ii) to consider different scenarios of environmental disruption (excess of nutrients, diffuse or massive pollution, exploitation by man, climate change) to forecast effects on growth, reproduction and survival of key species; (iii) to scale up the models for a few species from

  9. Soil type and species diversity influence selection on physiology in Panicum virgatum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species diversity influences the productivity and stability of plant communities, but its effect on the evolution of species within those communities is poorly understood. In this study, we tested whether species diversity and soil type influence selection on physiology in switchgrass (Panicum virga...

  10. Compelling classroom demonstrations that link visual system anatomy, physiology, and behaviour.

    PubMed

    O'Drobinak, David M; Woods, Charles B

    2002-12-01

    One of our approaches to teaching a course in anatomy and physiology is to stress the fundamental, systems-level concepts. One successful strategy we use is to continually highlight the relationships among anatomy, physiology, and behavior. In this article, we describe a set of classroom demonstrations that stress these links while fostering critical thinking. These demonstrations, on the topic of sensory system structure and function, rely on two perceptual consequences of neural adaptation in the visual system: afterimages and aftereffects. Viewing specific visual stimuli under binocular or monocular conditions with interocular transfer permits several concepts to be observed and discussed, including neural adaptation, anatomical and functional segregation of visual system pathways, and the relationship among visual system structure, function, and perception. This article discusses how to produce and present the required visual stimuli, suggests a set of questions to stimulate critical thinking, and presents student evaluation of this activity. PMID:12189128

  11. Linking the investigations of character evolution and species diversification.

    PubMed

    Magnuson-Ford, Karen; Otto, Sarah P

    2012-08-01

    Variation in diversification rates is often studied by investigating traits related to species' ecology and life history. Often, however, it is unknown whether these traits evolve gradually or in punctuated bursts during speciation. Using phylogenetic data and species' present-day trait information, we present a novel approach to assessing the mode of character change while accounting for trait-dependent speciation and extinction. Our model, "Binary-State Speciation and Extinction-node enhanced state shift" (BiSSE-ness), estimates both the rate of change occurring along lineages and the probability of change occurring during speciation, as well as independent speciation and extinction rates for each character state. Using simulations, we found that BiSSE-ness is able to distinguish along-lineage and speciational change and accurately estimate the parameters associated with character change and diversification rates. We applied BiSSE-ness to an empirical primate data set and found evidence for along-lineage changes in primate mating systems and social behaviors, whereas shifts in habitat were associated with speciation. In cases where trait changes may be linked to the speciation process itself (e.g., niche-related traits), BiSSE-ness provides a suitable framework with which to simultaneously address questions regarding species diversification and character change. PMID:22766933

  12. Transcription termination factor Rho: a hub linking diverse physiological processes in bacteria.

    PubMed

    Grylak-Mielnicka, Aleksandra; Bidnenko, Vladimir; Bardowski, Jacek; Bidnenko, Elena

    2016-03-01

    Factor-dependent termination of transcription in bacteria relies on the activity of a specific RNA helicase, the termination factor Rho. Rho is nearly ubiquitous in bacteria, but the extent to which its physiological functions are conserved throughout the different phyla remains unknown. Most of our current knowledge concerning the mechanism of Rho's activity and its physiological roles comes from the model micro-organism Escherichia coli, where Rho is essential and involved in the control of several important biological processes. However, the rather comprehensive knowledge about the general mechanisms of action and activities of Rho based on the E. coli paradigm cannot be directly extrapolated to other bacteria. Recent studies performed in different species favour the view that Rho-dependent termination plays a significant role even in bacteria where Rho is not essential. Here, we summarize the current state of the ever-increasing knowledge about the various aspects of the physiological functions of Rho, such as limitation of deleterious foreign DNA expression, control of gene expression, suppression of pervasive transcription, prevention of R-loops and maintenance of chromosome integrity, focusing on similarities and differences of the activities of Rho in various bacterial species. PMID:26796109

  13. Speaking under pressure: Low linguistic complexity is linked to high physiological and emotional stress reactivity

    PubMed Central

    Saslow, Laura R.; McCoy, Shannon; van der Löwe, Ilmo; Cosley, Brandon; Vartan, Arbi; Oveis, Christopher; Keltner, Dacher; Moskowitz, Judith T.; Epel, Elissa S.

    2014-01-01

    What can a speech reveal about someone's state? We tested the idea that greater stress reactivity would relate to lower linguistic cognitive complexity while speaking. In Study 1, we tested whether heart rate and emotional stress reactivity to a stressful discussion would relate to lower linguistic complexity. In Studies 2 and 3 we tested whether a greater cortisol response to a standardized stressful task including a speech (Trier Social Stress Test) would be linked to speaking with less linguistic complexity during the task. We found evidence that measures of stress responsivity (emotional and physiological) and chronic stress are tied to variability in the cognitive complexity of speech. Taken together, these results provide evidence that our individual experiences of stress or ‘stress signatures’—how our body and mind react to stress both in the moment and over the longer term—are linked to how complexly we speak under stress. PMID:24354732

  14. Comparative physiology of sound localization in four species of owls.

    PubMed

    Volman, S F; Konishi, M

    1990-01-01

    Bilateral ear asymmetry is found in some, but not all, species of owls. We investigated the neural basis of sound localization in symmetrical and asymmetrical species, to deduce how ear asymmetry might have evolved from the ancestral condition, by comparing the response properties of neurons in the external nucleus of the inferior colliculus (ICx) of the symmetrical burrowing owl and asymmetrical long-eared owl with previous findings in the symmetrical great horned owl and asymmetrical barn owl. In the ICx of all of these owls, the neurons had spatially restricted receptive fields, and auditory space was topographically mapped. In the symmetrical owls, ICx units were not restricted in elevation, and only azimuth was mapped in ICx. In the barn owl, the space map is two-dimensional, with elevation forming the second dimension. Receptive fields in the long-eared owl were somewhat restricted in elevation, but their tuning was not sharp enough to determine if elevation is mapped. In every species, the primary cue for azimuth was interaural time difference, although ICx units were also tuned for interaural intensity difference (IID). In the barn owl, the IIDs of sounds with frequencies between about 5 and 8 kHz vary systematically with elevation, and the IID selectivity of ICx neurons primarily encodes elevation. In the symmetrical owls, whose ICx neurons do not respond to frequencies above about 5 kHz, IID appears to be a supplementary cue for azimuth. We hypothesize that ear asymmetry can be exploited by owls that have evolved the higher-frequency hearing necessary to generate elevation cues. Thus, the IID selectivity of ICx neurons in symmetrical owls may preadapt them for asymmetry; the neural circuitry that underlies IID selectivity is already present in symmetrical owls, but because IID is not absolutely required to encode azimuth it can come to encode elevation in asymmetrical owls. PMID:2279234

  15. Physiological Plasticity to Water Flow Habitat in the Damselfish, Acanthochromis polyacanthus: Linking Phenotype to Performance

    PubMed Central

    Binning, Sandra A.; Ros, Albert F. H.; Nusbaumer, David; Roche, Dominique G.

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  16. Physiological plasticity to water flow habitat in the damselfish, Acanthochromis polyacanthus: linking phenotype to performance.

    PubMed

    Binning, Sandra A; Ros, Albert F H; Nusbaumer, David; Roche, Dominique G

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  17. Use of automated monitoring to assess behavioral toxicology in fish: Linking behavior and physiology

    USGS Publications Warehouse

    Brewer, S.K.; DeLonay, A.J.; Beauvais, S.L.; Little, E.E.; Jones, S.B.

    1999-01-01

    We measured locomotory behaviors (distance traveled, speed, tortuosity of path, and rate of change in direction) with computer-assisted analysis in 30 day posthatch rainbow trout (Oncorhynchus mykiss) exposed to pesticides. We also examined cholinesterase inhibition as a potential endpoint linking physiology and behavior. Sublethal exposure to chemicals often causes changes in swimming behavior, reflecting alterations in sensory and motor systems. Swimming behavior also integrates functions of the nervous system. Rarely are the connections between physiology and behavior made. Although behavior is often suggested as a sensitive, early indicator of toxicity, behavioral toxicology has not been used to its full potential because conventional methods of behavioral assessment have relied on manual techniques, which are often time-consuming and difficult to quantify. This has severely limited the application and utility of behavioral procedures. Swimming behavior is particularly amenable to computerized assessment and automated monitoring. Locomotory responses are sensitive to toxicants and can be easily measured. We briefly discuss the use of behavior in toxicology and automated techniques used in behavioral toxicology. We also describe the system we used to determine locomotory behaviors of fish, and present data demonstrating the system's effectiveness in measuring alterations in response to chemical challenges. Lastly, we correlate behavioral and physiological endpoints.

  18. Physiology

    ERIC Educational Resources Information Center

    Kay, Ian

    2008-01-01

    Underlying recent developments in health care and new treatments for disease are advances in basic medical sciences. This edition of "Webwatch" focuses on sites dealing with basic medical sciences, with particular attention given to physiology. There is a vast amount of information on the web related to physiology. The sites that are included here…

  19. Physiological responses to water stress and waterlogging in Nothofagus species.

    PubMed

    Sun, O J; Sweet, G B; Whitehead, D; Buchan, G D

    1995-10-01

    Gas exchange and water relations were investigated in Nothofagus solandri var. cliffortioides (Hook. f.) Poole (mountain beech) and Nothofagus menziesii (Hook. f.) Oerst (silver beech) seedlings in response to water stress and waterlogging. At soil matric potentials (Psi(soil)) above -0.005 MPa, N. solandri had significantly higher photosynthetic rates (A), and stomatal and residual conductances (g(sw) and g(rc)), and lower predawn xylem water potentials (Psi(predawn)) than N. menziesii. The relative tolerance of plants to water stress was defined in terms of critical soil matric potential (Psi(cri)) and lethal xylem water potential (Psi(lethal)). The estimated values of Psi(cri) and Psi(lethal) were -1.2 and -7 MPa, respectively, for N. solandri, and -0.7 and -4 MPa, respectively, for N. menziesii. Photosynthesis was sustained to a xylem water potential (Psi(xylem)) of -7 MPa in N. solandri compared with -4 MPa in N. menziesii. Following rewatering, both A and Psi(xylem) recovered quickly in N. solandri, whereas the two variables recovered more slowly in N. menziesii. During the development of water stress, nonstomatal inhibition significantly affected A in both N. solandri and N. menziesii. Nothofagus menziesii was more susceptible to inhibition of A by waterlogging than N. solandri. However, the tolerance of N. solandri to severe waterlogging was also limited as a result of a failure to form adventitious roots, suggesting a lack of adaptation to these conditions. The differences in tolerance to water stress and waterlogging between the two species are consistent with the distribution patterns of N. solandri and N. menziesii in New Zealand. PMID:14965996

  20. The Coordination of Leaf Photosynthesis Links C and N Fluxes in C3 Plant Species

    PubMed Central

    Maire, Vincent; Martre, Pierre; Kattge, Jens; Gastal, François; Esser, Gerd; Fontaine, Sébastien; Soussana, Jean-François

    2012-01-01

    Photosynthetic capacity is one of the most sensitive parameters in vegetation models and its relationship to leaf nitrogen content links the carbon and nitrogen cycles. Process understanding for reliably predicting photosynthetic capacity is still missing. To advance this understanding we have tested across C3 plant species the coordination hypothesis, which assumes nitrogen allocation to photosynthetic processes such that photosynthesis tends to be co-limited by ribulose-1,5-bisphosphate (RuBP) carboxylation and regeneration. The coordination hypothesis yields an analytical solution to predict photosynthetic capacity and calculate area-based leaf nitrogen content (Na). The resulting model linking leaf photosynthesis, stomata conductance and nitrogen investment provides testable hypotheses about the physiological regulation of these processes. Based on a dataset of 293 observations for 31 species grown under a range of environmental conditions, we confirm the coordination hypothesis: under mean environmental conditions experienced by leaves during the preceding month, RuBP carboxylation equals RuBP regeneration. We identify three key parameters for photosynthetic coordination: specific leaf area and two photosynthetic traits (k3, which modulates N investment and is the ratio of RuBP carboxylation/oxygenation capacity () to leaf photosynthetic N content (Npa); and Jfac, which modulates photosynthesis for a given k3 and is the ratio of RuBP regeneration capacity (Jmax) to). With species-specific parameter values of SLA, k3 and Jfac, our leaf photosynthesis coordination model accounts for 93% of the total variance in Na across species and environmental conditions. A calibration by plant functional type of k3 and Jfac still leads to accurate model prediction of Na, while SLA calibration is essentially required at species level. Observed variations in k3 and Jfac are partly explained by environmental and phylogenetic constraints, while SLA variation is partly explained

  1. Integrative modelling reveals mechanisms linking productivity and plant species richness

    NASA Astrophysics Data System (ADS)

    Grace, James B.; Anderson, T. Michael; Seabloom, Eric W.; Borer, Elizabeth T.; Adler, Peter B.; Harpole, W. Stanley; Hautier, Yann; Hillebrand, Helmut; Lind, Eric M.; Pärtel, Meelis; Bakker, Jonathan D.; Buckley, Yvonne M.; Crawley, Michael J.; Damschen, Ellen I.; Davies, Kendi F.; Fay, Philip A.; Firn, Jennifer; Gruner, Daniel S.; Hector, Andy; Knops, Johannes M. H.; MacDougall, Andrew S.; Melbourne, Brett A.; Morgan, John W.; Orrock, John L.; Prober, Suzanne M.; Smith, Melinda D.

    2016-01-01

    How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

  2. Integrative modelling reveals mechanisms linking productivity and plant species richness.

    PubMed

    Grace, James B; Anderson, T Michael; Seabloom, Eric W; Borer, Elizabeth T; Adler, Peter B; Harpole, W Stanley; Hautier, Yann; Hillebrand, Helmut; Lind, Eric M; Pärtel, Meelis; Bakker, Jonathan D; Buckley, Yvonne M; Crawley, Michael J; Damschen, Ellen I; Davies, Kendi F; Fay, Philip A; Firn, Jennifer; Gruner, Daniel S; Hector, Andy; Knops, Johannes M H; MacDougall, Andrew S; Melbourne, Brett A; Morgan, John W; Orrock, John L; Prober, Suzanne M; Smith, Melinda D

    2016-01-21

    How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems. PMID:26760203

  3. Linking hydrothermal geochemistry to organismal physiology: physiological versatility in Riftia pachyptila from sedimented and basalt-hosted vents.

    PubMed

    Robidart, Julie C; Roque, Annelys; Song, Pengfei; Girguis, Peter R

    2011-01-01

    Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR). These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted vents, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, hydrothermal vent field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that--contrary to previous assertions--Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution. PMID:21779334

  4. Small Fish Species as Powerful Model Systems to Study Vertebrate Physiology in Space

    NASA Astrophysics Data System (ADS)

    Muller, M.; Aceto, J.; Dalcq, J.; Alestrom, P.; Nourizadeh-Lillabadi, R.; Goerlich, R.; Schiller, V.; Winkler, C.; Renn, J.; Eberius, M.; Slenzka, K.

    2008-06-01

    Small fish models, mainly zebrafish (Danio rerio) and medaka (Oryzias latipes), have been used for many years as powerful model systems for vertebrate developmental biology. Moreover, these species are increasingly recognized as valuable systems to study vertebrate physiology, pathology, pharmacology and toxicology, including in particular bone physiology. The biology of small fishes presents many advantages, such as transparency of the embryos, external and rapid development, small size and easy reproduction. Further characteristics are particularly useful for space research or for large scale screening approaches. Finally, many technologies for easily characterizing bones are available. Our objective is to investigate the changes induced by microgravity in small fish. By combining whole genome analysis (microarray, DNA methylation, chromatin modification) with live imaging of selected genes in transgenic animals, a comprehensive and integrated characterization of physiological changes in space could be gained, especially concerning bone physiology.

  5. A link between eumelanism and calcium physiology in the barn owl

    NASA Astrophysics Data System (ADS)

    Roulin, Alexandre; Dauwe, Tom; Blust, Ronny; Eens, Marcel; Beaud, Michel

    2006-09-01

    In many animals, melanin-based coloration is strongly heritable and is largely insensitive to the environment and body condition. According to the handicap principle, such a trait may not reveal individual quality because the production of different melanin-based colorations often entails similar costs. However, a recent study showed that the production of eumelanin pigments requires relatively large amounts of calcium, potentially implying that melanin-based coloration is associated with physiological processes requiring calcium. If this is the case, eumelanism may be traded-off against other metabolic processes that require the same elements. We used a correlative approach to examine, for the first time, this proposition in the barn owl, a species in which individuals vary in the amount, size, and blackness of eumelanic spots. For this purpose, we measured calcium concentration in the left humerus of 85 dead owls. Results showed that the humeri of heavily spotted individuals had a higher concentration of calcium. This suggests either that plumage spottiness signals the ability to absorb calcium from the diet for both eumelanin production and storage in bones, or that lightly spotted individuals use more calcium for metabolic processes at the expense of calcium storage in bones. Our study supports the idea that eumelanin-based coloration is associated with a number of physiological processes requiring calcium.

  6. Eco-physiological adaptation of dominant tree species at two contrasting karst habitats in southwestern China

    PubMed Central

    Wu, Qian; Yan, Hui; Xu, Xinwu

    2013-01-01

    The purpose of this study was to investigate the eco-physiological adaptation of indigenous woody species to their habitats in karst areas of southwestern China. Two contrasting forest habitats were studied: a degraded habitat in Daxiagu and a well-developed habitat in Tianlongshan, and the eco-physiological characteristics of the trees were measured for three growth seasons. Photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr) of the tree species in Daxiagu were 2-3 times higher than those in Tianlongshan under ambient conditions. However, this habitat effect was not significant when measurements were taken under controlled conditions. Under controlled conditions, Pn, gs, and Tr of the deciduous species were markedly higher than those for the evergreen species. Habitat had no significant effect on water use efficiency (WUE) or photochemical characteristics of PSII. The stomatal sensitivity of woody species in the degraded habitat was much higher than that in the well-developed habitat. Similarly, the leaf total nitrogen (N) and phosphorus (P) contents expressed on the basis of either dry mass or leaf area were also much higher in Daxiagu than they were in Tianlongshan. The mass-based leaf total N content of deciduous species was much higher than that of evergreen species, while leaf area-based total N and P contents of evergreens were significantly higher than those of deciduous species. The photosynthetic nitrogen- and phosphorus-use efficiencies (PNUE and PPUE) of deciduous species were much higher than those of evergreens. Further, the PPUE of the woody species in Tianlongshan was much higher than that  of the woody species in Daxiagu. The results from three growth seasons imply that the tree species were able to adapt well to their growth habitats. Furthermore, it seems that so-called “temporary drought stress” may not occur, or may not be severe for most woody plants in karst areas of southwestern China. PMID:24555059

  7. Oma1 Links Mitochondrial Protein Quality Control and TOR Signaling To Modulate Physiological Plasticity and Cellular Stress Responses.

    PubMed

    Bohovych, Iryna; Kastora, Stavroula; Christianson, Sara; Topil, Danelle; Kim, Heejeong; Fangman, Teresa; Zhou, You J; Barrientos, Antoni; Lee, Jaekwon; Brown, Alistair J P; Khalimonchuk, Oleh

    2016-09-01

    A network of conserved proteases known as the intramitochondrial quality control (IMQC) system is central to mitochondrial protein homeostasis and cellular health. IMQC proteases also appear to participate in establishment of signaling cues for mitochondrion-to-nucleus communication. However, little is known about this process. Here, we show that in Saccharomyces cerevisiae, inactivation of the membrane-bound IMQC protease Oma1 interferes with oxidative-stress responses through enhanced production of reactive oxygen species (ROS) during logarithmic growth and reduced stress signaling via the TORC1-Rim15-Msn2/Msn4 axis. Pharmacological or genetic prevention of ROS accumulation in Oma1-deficient cells restores this defective TOR signaling. Additionally, inactivation of the Oma1 ortholog in the human fungal pathogen Candida albicans also alters TOR signaling and, unexpectedly, leads to increased resistance to neutrophil killing and virulence in the invertebrate animal model Galleria mellonella Our findings reveal a novel and evolutionarily conserved link between IMQC and TOR-mediated signaling that regulates physiological plasticity and pancellular oxidative-stress responses. PMID:27325672

  8. Physiological epicotyl dormancy and recalcitrant storage behaviour in seeds of two tropical Fabaceae (subfamily Caesalpinioideae) species

    PubMed Central

    Jayasuriya, K. M. G. Gehan; Wijetunga, Asanga S. T. B.; Baskin, Jerry M.; Baskin, Carol C.

    2012-01-01

    Background and aims Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. Methodology Fresh seeds were (i) dried to various moisture levels, and (ii) stored at −1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. Principal results Fresh seeds of both species had high moisture content (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at −1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them in <30 days. However, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ∼30–35 days in B. coccinea seeds. Conclusions Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is Cnd (root)− (epicotyl). PMID

  9. Does including physiology improve species distribution model predictions of responses to recent climate change?

    PubMed

    Buckley, Lauren B; Waaser, Stephanie A; MacLean, Heidi J; Fox, Richard

    2011-12-01

    Thermal constraints on development are often invoked to predict insect distributions. These constraints tend to be characterized in species distribution models (SDMs) by calculating development time based on a constant lower development temperature (LDT). Here, we assessed whether species-specific estimates of LDT based on laboratory experiments can improve the ability of SDMs to predict the distribution shifts of six U.K. butterflies in response to recent climate warming. We find that species-specific and constant (5 degrees C) LDT degree-day models perform similarly at predicting distributions during the period of 1970-1982. However, when the models for the 1970-1982 period are projected to predict distributions in 1995-1999 and 2000-2004, species-specific LDT degree-day models modestly outperform constant LDT degree-day models. Our results suggest that, while including species-specific physiology in correlative models may enhance predictions of species' distribution responses to climate change, more detailed models may be needed to adequately account for interspecific physiological differences. PMID:22352161

  10. Beta-2-linked glucans secreted by fast-growing species of Rhizobium

    SciTech Connect

    York, W.S.; McNeil, M.; Darvill, A.G.; Albersheim, P.

    1980-04-01

    Fast-growing species of Rhizobium were found to secrete low-molecular-weight ..beta..-2-linked glucans when cultured in synthetic liquid medium. These glucans are quite similar to ..beta..-2-linked glucans produced by species of Agrobacterium. No reducing terminus was detected in these glucans.

  11. Beta-2-linked glucans secreted by fast-growing species of Rhizobium.

    PubMed Central

    York, W S; McNeil, M; Darvill, A G; Albersheim, P

    1980-01-01

    Fast-growing species of Rhizobium were found to secrete low-molecular-weight beta-2-linked glucans when cultured in synthetic liquid medium. These glucans are quite similar to beta-2-linked glucans produced by species of Agrobacterium. No reducing terminus was detected in these glucans. PMID:7372570

  12. On the physiological/pathological link between Aβ peptide, cholesterol, calcium ions and membrane deformation: A molecular dynamics study.

    PubMed

    Pannuzzo, Martina

    2016-06-01

    The dynamic interplay between cholesterol, asymmetrically (at physiological condition) or symmetrically (hallmark of aging) distributed in membrane, and β amyloid peptides is investigated by a computational approach. The drawn overall picture, starting from the very appearance of β amyloid peptides and going through their self-assembling into potentially toxic oligomeric species, reinforces some of the experimental and theoretical shots recently reported in literature, while new important molecular hints on the physiological role played by the β amyloid peptide are proposed. The so dreaded formation of amyloid pores selective for the passage of calcium ions could in fact explain their physiological concomitant recruitment in the regulation of synaptic plasticity. PMID:27003127

  13. Familiarity bias and physiological responses in contagious yawning by dogs support link to empathy.

    PubMed

    Romero, Teresa; Konno, Akitsugu; Hasegawa, Toshikazu

    2013-01-01

    In humans, the susceptibility to yawn contagion has been theoretically and empirically related to our capacity for empathy. Because of its relevance to evolutionary biology, this phenomenon has been the focus of recent investigations in non-human species. In line with the empathic hypothesis, contagious yawning has been shown to correlate with the level of social attachment in several primate species. Domestic dogs (Canis familiaris) have also shown the ability to yawn contagiously. To date, however, the social modulation of dog contagious yawning has received contradictory support and alternative explanations (i.e., yawn as a mild distress response) could explain positive evidence. The present study aims to replicate contagious yawning in dogs and to discriminate between the two possible mediating mechanisms (i.e., empathic vs. distress related response). Twenty-five dogs observed familiar (dog's owner) and unfamiliar human models (experimenter) acting out a yawn or control mouth movements. Concurrent physiological measures (heart rate) were additionally monitored for twenty-one of the subjects. The occurrence of yawn contagion was significantly higher during the yawning condition than during the control mouth movements. Furthermore, the dogs yawned more frequently when watching the familiar model than the unfamiliar one demonstrating that the contagiousness of yawning in dogs correlated with the level of emotional proximity. Moreover, subjects' heart rate did not differ among conditions suggesting that the phenomenon of contagious yawning in dogs is unrelated to stressful events. Our findings are consistent with the view that contagious yawning is modulated by affective components of the behavior and may indicate that rudimentary forms of empathy could be present in domesticated dogs. PMID:23951146

  14. Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

    PubMed Central

    Romero, Teresa; Konno, Akitsugu; Hasegawa, Toshikazu

    2013-01-01

    In humans, the susceptibility to yawn contagion has been theoretically and empirically related to our capacity for empathy. Because of its relevance to evolutionary biology, this phenomenon has been the focus of recent investigations in non-human species. In line with the empathic hypothesis, contagious yawning has been shown to correlate with the level of social attachment in several primate species. Domestic dogs (Canis familiaris) have also shown the ability to yawn contagiously. To date, however, the social modulation of dog contagious yawning has received contradictory support and alternative explanations (i.e., yawn as a mild distress response) could explain positive evidence. The present study aims to replicate contagious yawning in dogs and to discriminate between the two possible mediating mechanisms (i.e., empathic vs. distress related response). Twenty-five dogs observed familiar (dog’s owner) and unfamiliar human models (experimenter) acting out a yawn or control mouth movements. Concurrent physiological measures (heart rate) were additionally monitored for twenty-one of the subjects. The occurrence of yawn contagion was significantly higher during the yawning condition than during the control mouth movements. Furthermore, the dogs yawned more frequently when watching the familiar model than the unfamiliar one demonstrating that the contagiousness of yawning in dogs correlated with the level of emotional proximity. Moreover, subjects’ heart rate did not differ among conditions suggesting that the phenomenon of contagious yawning in dogs is unrelated to stressful events. Our findings are consistent with the view that contagious yawning is modulated by affective components of the behavior and may indicate that rudimentary forms of empathy could be present in domesticated dogs. PMID:23951146

  15. Linking species functional roles to their network roles.

    PubMed

    Coux, Camille; Rader, Romina; Bartomeus, Ignasi; Tylianakis, Jason M

    2016-07-01

    Species roles in ecological networks combine to generate their architecture, which contributes to their stability. Species trait diversity also affects ecosystem functioning and resilience, yet it remains unknown whether species' contributions to functional diversity relate to their network roles. Here, we use 21 empirical pollen transport networks to characterise this relationship. We found that, apart from a few abundant species, pollinators with original traits either had few interaction partners or interacted most frequently with a subset of these partners. This suggests that narrowing of interactions to a subset of the plant community accompanies pollinator niche specialisation, congruent with our hypothesised trade-off between having unique traits vs. being able to interact with many mutualist partners. Conversely, these effects were not detected in plants, potentially because key aspects of their flowering traits are conserved at a family level. Relating functional and network roles can provide further insight into mechanisms underlying ecosystem functioning. PMID:27169359

  16. Functional diversity supports the physiological tolerance hypothesis for plant species richness along climatic gradients

    USGS Publications Warehouse

    Spasojevic, Marko J.; Grace, James B.; Harrison, Susan; Damschen, Ellen Ingman

    2013-01-01

    1. The physiological tolerance hypothesis proposes that plant species richness is highest in warm and/or wet climates because a wider range of functional strategies can persist under such conditions. Functional diversity metrics, combined with statistical modeling, offer new ways to test whether diversity-environment relationships are consistent with this hypothesis. 2. In a classic study by R. H. Whittaker (1960), herb species richness declined from mesic (cool, moist, northerly) slopes to xeric (hot, dry, southerly) slopes. Building on this dataset, we measured four plant functional traits (plant height, specific leaf area, leaf water content and foliar C:N) and used them to calculate three functional diversity metrics (functional richness, evenness, and dispersion). We then used a structural equation model to ask if ‘functional diversity’ (modeled as the joint responses of richness, evenness, and dispersion) could explain the observed relationship of topographic climate gradients to species richness. We then repeated our model examining the functional diversity of each of the four traits individually. 3. Consistent with the physiological tolerance hypothesis, we found that functional diversity was higher in more favorable climatic conditions (mesic slopes), and that multivariate functional diversity mediated the relationship of the topographic climate gradient to plant species richness. We found similar patterns for models focusing on individual trait functional diversity of leaf water content and foliar C:N. 4. Synthesis. Our results provide trait-based support for the physiological tolerance hypothesis, suggesting that benign climates support more species because they allow for a wider range of functional strategies.

  17. Linking Myometrial Physiology to Intrauterine Pressure; How Tissue-Level Contractions Create Uterine Contractions of Labor

    PubMed Central

    Young, Roger C.; Barendse, Peter

    2014-01-01

    The mechanisms used to coordinate uterine contractions are not known. We develop a new model based on the proposal that there is a maximum distance to which action potentials can propagate in the uterine wall. This establishes “regions”, where one action potential burst can rapidly recruit all the tissue. Regions are recruited into an organ-level contraction via a stretch-initiated contraction mechanism (myometrial myogenic response). Each uterine contraction begins with a regional contraction, which slightly increases intrauterine pressure. Higher pressure raises tension throughout the uterine wall, which initiates contractions of more regions and further increases pressure. The positive feedback synchronizes regional contractions into an organ-level contraction. Cellular automaton (CA) simulations are performed with Mathematica. Each “cell” is a region that is assigned an action potential threshold. An anatomy sensitivity factor converts intrauterine pressure to regional tension through the Law of Laplace. A regional contraction occurs when regional tension exceeds regional threshold. Other input variables are: starting and minimum pressure, burst and refractory period durations, enhanced contractile activity during an electrical burst, and reduced activity during the refractory period. Complex patterns of pressure development are seen that mimic the contraction patterns observed in laboring women. Emergent behavior is observed, including global synchronization, multiple pace making regions, and system memory of prior conditions. The complex effects of nifedipine and oxytocin exposure are simulated. The force produced can vary as a nonlinear function of the number of regions. The simulation directly links tissue-level physiology to human labor. The concept of a uterine pacemaker is re-evaluated because pace making activity may occur well before expression of a contraction. We propose a new classification system for biological CAs that parallels the 4

  18. Physiological and genetic effects of chromium (+VI) on toxitolerant lichen species, Pyxine cocoes.

    PubMed

    Bajpai, Rajesh; Shukla, Vertika; Singh, Niraj; Rana, T S; Upreti, D K

    2015-03-01

    Chromium is a highly toxic non-essential metal, which causes a variety of metabolic activities in plants. Pyxine cocoes a well known toxitolerant lichen species was considered to evaluate the possible physiological, biochemical, and genetic changes that occur due to chromium Cr (+VI) stress. The physiological (chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, protein, and Fv/Fm) and genetic (ISSR-PCR and ITS) parameters were used to estimate the changes in P. cocoes. Different concentrations of Cr (+VI) (0, 10, 25, 50, 75, and 100 μM) for 10, 20, 30, and 45 days were employed on transplanted lichen species. The results revealed that the exposure of Cr (+VI) for 10, 20, 30, and 45 days under controlled conditions caused a significant decline in physiological processes with increasing metal stress. Amino acid profile at different concentrations on the 45th day too indicated prevailing stress condition as proline content significantly increased at 100 μM concentration. Inter-simple sequence repeat (ISSR) and internal transcribed spacer (ITS) techniques were used to evaluate the genotoxicity induced by chromium stress. ISSR profiles showed a consistent increase in appearance and disappearance of bands with increasing concentration of the chromium. ISSR technique, therefore, is more sensitive and reproducible to study polymorphism induced by environmental stress. The present study revealed that the physiological and genetic changes induced by the Cr (+VI) can be used as a tool to study environmental stress and polymorphisms due to genotoxicity. To the best of our knowledge, application of ISSR-PCR and ITS sequences in toxitolerant species (P. cocoes) appears to be the maiden attempt to evaluate the genotoxicity. PMID:25263416

  19. Integrative modelling reveals mechanisms linking productivity and plant species richness

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For 40 years ecologists have sought a canonical productivity-species richness relationship 48 (PRR) for ecosystems, despite continuing disagreements about expected form and 49 interpretation. Using a large global dataset of terrestrial grasslands, we consider how 50 productivity and richness relate ...

  20. Tameness and stress physiology in a predator-naive island species confronted with novel predation threat

    PubMed Central

    Rödl, Thomas; Berger, Silke; Michael Romero, L; Wikelski, Martin

    2006-01-01

    Tame behaviour, i.e. low wariness, in terrestrial island species is often attributed to low predation pressure. However, we know little about its physiological control and its flexibility in the face of predator introductions. Marine iguanas (Amblyrhynchus cristatus) on the Galápagos Islands are a good model to study the physiological correlates of low wariness. They have lived virtually without predation for 5–15 Myr until some populations were first confronted with feral cats and dogs some 150 years ago. We tested whether and to what extent marine iguanas can adjust their behaviour and endocrine stress response to novel predation threats. Here, we show that a corticosterone stress response to experimental chasing is absent in naive animals, but is quickly restored with experience. Initially, low wariness also increases with experience, but remains an order of magnitude too low to allow successful escape from introduced predators. Our data suggest that the ability of marine iguanas to cope with predator introductions is limited by narrow reaction norms for behavioural wariness rather than by constraints in the underlying physiological stress system. In general, we predict that island endemics show flexible physiological stress responses but are restricted by narrow behavioural plasticity. PMID:17476779

  1. Reactive oxygen species: physiological roles in the regulation of vascular cells.

    PubMed

    Vara, D; Pula, G

    2014-01-01

    Reactive oxygen species (ROS) are now appreciated to play several important roles in a number of biological processes and regulate cell physiology and function. ROS are a heterogeneous chemical class that includes radicals, such as superoxide ion (O2(•-)), hydroxyl radical (OH(•)) and nitric oxide (NO(•)), and non-radicals, such as hydrogen peroxide (H2O2), singlet oxygen ((1)O2), hypochlorous acid (HOCl), and peroxynitrite (NO3 (-)). In the cardiovascular system, besides playing a critical role in the development and progression of vasculopathies and other important pathologies such as congestive heart failure, atherosclerosis and thrombosis, ROS also regulate physiological processes. Evidence from a wealth of cardiovascular research studies suggests that ROS act as second messengers and play an essential role in vascular homeostasis by influencing discrete signal transduction pathways in various systems and cell types. They are produced throughout the vascular system, regulate differentiation and contractility of vascular smooth muscle cells, control vascular endothelial cell proliferation and migration, mediate platelet activation and haemostasis, and significantly contribute to the immune response. Our understanding of ROS chemistry and cell biology has evolved to the point of realizing that different ROS have distinct and important roles in cardiovascular physiology. This review will outline sources, functions and molecular mechanisms of action of different ROS in the cardiovascular system and will describe their emerging role in healthy cardiovascular physiology and homeostasis. PMID:24894168

  2. Is Physiological Performance a Good Predictor for Fitness? Insights from an Invasive Plant Species

    PubMed Central

    Molina-Montenegro, Marco A.; Salgado-Luarte, Cristian; Oses, Rómulo; Torres-Díaz, Cristian

    2013-01-01

    Is physiological performance a suitable proxy of fitness in plants? Although, several studies have been conducted to measure some fitness-related traits and physiological performance, direct assessments are seldom found in the literature. Here, we assessed the physiology-fitness relationship using second-generation individuals of the invasive plant species Taraxacum officinale from 17 localities distributed in five continents. Specifically, we tested if i) the maximum quantum yield is a good predictor for seed-output ii) whether this physiology-fitness relationship can be modified by environmental heterogeneity, and iii) if this relationship has an adaptive consequence for T. officinale individuals from different localities. Overall, we found a significant positive relationship between the maximum quantum yield and fitness for all localities evaluated, but this relationship decreased in T. officinale individuals from localities with greater environmental heterogeneity. Finally, we found that those individuals from localities where environmental conditions are highly seasonal performed better under heterogeneous environmental conditions. Contrarily, under homogeneous controlled conditions, those individuals from localities with low environmental seasonality performed much better. In conclusion, our results suggest that the maximum quantum yield seem to be good predictors for plant fitness. We suggest that rapid measurements, such as those obtained from the maximum quantum yield, could provide a straightforward proxy of individual’s fitness in changing environments. PMID:24204626

  3. Mammal predator and prey species richness are strongly linked at macroscales.

    PubMed

    Sandom, Christopher; Dalby, Lars; Fløjgaard, Camilla; Kissling, W Daniel; Lenoir, Jonathan; Sandel, Brody; Trøjelsgaard, Kristian; Ejrnaes, Rasmus; Svenning, Jens-Christian

    2013-05-01

    Predator-prey interactions play an important role for species composition and community dynamics at local scales, but their importance in shaping large-scale gradients of species richness remains unexplored. Here, we use global range maps, structural equation models (SEM), and comprehensive databases of dietary preferences and body masses of all terrestrial, non-volant mammals worldwide, to test whether (1) prey bottom-up or predator top-down relationships are important drivers of broad-scale species richness gradients once the environment and human influence have been accounted for, (2) predator-prey richness associations vary among biogeographic regions, and (3) body size influences large-scale covariation between predators and prey. SEMs including only productivity, climate, and human factors explained a high proportion of variance in prey richness (R2=0.56) but considerably less in predator richness (R2=0.13). Adding predator-to-prey or prey-to-predator paths strongly increased the explained variance in both cases (prey R2=0.79, predator R2=0.57), suggesting that predator-prey interactions play an important role in driving global diversity gradients. Prey bottom-up effects prevailed over productivity, climate, and human influence to explain predator richness, whereas productivity and climate were more important than predator top-down effects for explaining prey richness, although predator top-down effects were still significant. Global predator-prey associations were not reproduced in all regions, indicating that distinct paleoclimate and evolutionary histories (Africa and Australia) may alter species interactions across trophic levels. Stronger cross-trophic-level associations were recorded within categories of similar body size (e.g., large prey to large predators) than between them (e.g., large prey to small predators), suggesting that mass-related energetic and physiological constraints influence broad-scale richness links, especially for large

  4. Binary pulsar evolution: unveiled links and new species

    NASA Astrophysics Data System (ADS)

    Possenti, Andrea

    2013-03-01

    In the last years a series of blind and/or targeted pulsar searches led to almost triple the number of known binary pulsars in the galactic field with respect to a decade ago. The focus will be on few outliers, which are emerging from the average properties of the enlarged binary pulsar population. Some of them may represent the long sought missing links between two kinds of neutron star binaries, while others could represent the stereotype of new groups of binaries, resulting from an evolutionary path which is more exotic than those considered until recently. In particular, a new class of binaries, which can be dubbed Ultra Low Mass Binary Pulsars (ULMBPs), is emerging from recent data.

  5. Linking microbial ultrastructure and physiology to iron depositional processes in deep sea hydrothermal environments

    NASA Astrophysics Data System (ADS)

    Chan, C. S.; Fleming, E. J.; Emerson, D.; Edwards, K. J.

    2008-12-01

    Clara S. Chan, Emily Fleming, David Emerson, Katrina J. Edwards Iron microbial mats have been discovered in a variety of deep-sea hydrothermal environments and are increasingly being recognized as more seafloor is explored. The predominant structures found in many of these mats are iron oxyhydroxide-rich filaments. One of the most common structures is a helical stalk bearing a resemblance to the twisted stalk of the terrestrial iron-oxidizing microbe, Gallionella ferruginea. While Gallionella has not been detected in, or isolated from, these mats microaerophilic iron-oxidizing, a stalk- forming bacterium, Mariprofundus ferrooxydans (PV-1 and related strains) has been isolated from mats at the Loihi seamount in Hawaii (Emerson et al. 2007, PLoS One 2(8): e667). Fossilized aggregates of iron filaments have been observed in the rock record (e.g. Little et al. 2004, Geomicrobiol. J. 21:415), and may represent ancient versions of these microbial mats. If this is shown to be true, such filaments would represent one of the few microfossil morphologies that can be linked to a specific microbial metabolism. We have used a combination of test tube culturing, microslide culturing, time lapse microscopy, and electron microscopy to study Mariprofundus stalk morphology and genesis and link these details to physiological responses to environmental chemistry. The goals include determining specific attributes of stalk morphology that can be used to determine the biogenicity of putative iron microfossils, and interpret the conditions of the depositional environment. Light microscopic observation of microslide cultures over the course of several days allowed for determination of bacterial response to developing oxygen and Fe(II) gradients. Once gradients have been established, given an abundant supply of oxygen, cells congregate in a band perpendicular to the gradient and stalks are formed, growing in the direction of increasing oxygen (and decreasing Fe) concentration. This

  6. Osmotolerant yeast species differ in basic physiological parameters and in tolerance of non-osmotic stresses.

    PubMed

    Bubnová, Michala; Zemančíková, Jana; Sychrová, Hana

    2014-08-01

    Osmotolerance is the ability to grow in an environment with a high osmotic pressure. In this study we compared the physiological parameters and tolerance to osmotic and non-osmotic stresses of three osmotolerant yeast species, Debaryomyces hansenii, Pichia farinosa (sorbitophila) and Zygosaccharomyces rouxii, with those of wild-type Saccharomyces cerevisiae. Although the osmotolerant species did not differ significantly in their basic parameters, such as cell size or growth capacity, they had different abilities to survive anhydrobiosis, potassium limitation or the presence of toxic cationic drugs. When their osmotolerance was compared, the results revealed that some of the species isolated as sugar/polyol-tolerant (e.g.  P. farinosa) are also highly tolerant to salts and, vice versa, some strains isolated from an environment with high concentration of salt (e.g. Z. rouxii ATCC 42981) tolerate high concentrations of sugars. None of the tested strains and species was osmophilic. Taken together, our results showed that P. farinosa (sorbitophila) is the most robust species when coping with various stresses, while Z. rouxii CBS 732, although osmotolerant in general, is not specifically salt-tolerant and is quite sensitive to most of the tested stress conditions. PMID:24962688

  7. Physiological characteristics of tropical rain forest tree species: A basis for the development of silvicultural technology

    PubMed Central

    SASAKI, Satohiko

    2008-01-01

    The physiological characteristics of the dominant tree species in the tropical rain forest mainly belonging to dipterocarps as well as the environmental conditions especially for the light in the forest were studied to establish the silvicultural system for the forest regeneration in the tropical South Asia. The flowering patterns of the dipterocarp trees are usually irregular and unpredictable, which make difficult to collect sufficient seeds for raising the seedlings. The field survey revealed the diverged features of the so-called gregarious or simultaneous flowering of various species of this group. Appropriate conditions and methods for the storage of the seeds were established according to the detailed analyses of the morphological and physiological characteristics of the seeds such as the low temperature tolerance and the moisture contents. The intensity and spectra of the light in the forest primarily determine the growth and the morphological development of the seedlings under the canopy. Based on the measurements of the diffused light at the sites in the tropical forest in the varying sunlight, the parameters such as “the steady state of the diffuse light” and “the turning point” were defined, which were useful to evaluate the light conditions in the forest. To improve the survival of the transplanted seedlings, a planting method of “the bare-root seedlings”, the seedlings easy to be handled by removal of all leaves, soil and pots, was developed. Its marked efficiency was proved with various dipterocarps and other tropical trees by the field trial in the practical scale. Tolerance of the various species to the extreme environmental conditions such as fires, acid soils and drought were examined by the experiments and the field survey, which revealed marked adaptability of Shorea roxburghii as a potential species for regeneration of the tropical forests. PMID:18941286

  8. Divergent Egg Physiologies in Two Closely Related Grasshopper Species: Taeniopoda eques versus Romalea microptera (Orthoptera: Romaleidae)

    PubMed Central

    STAUFFER, TIMOTHY W.; HATLE, JOHN D.; WHITMAN, DOUGLAS W.

    2013-01-01

    We compared egg survivorship and egg development time at different soil moistures for two closely related grasshopper species from divergent habitats: marsh-inhabiting Romalea microptera (Beauvois) versus desert-inhabiting Taeniopoda eques (Burmeister). These two species can interbreed and produce viable offspring. In nature, both species have a similar 8–9 mo subterranean egg stage, but their soil environments differ dramatically in water content. We predicted that the eggs of the two species would exhibit differential survivorship and development times under different moisture levels. Our laboratory results show that the eggs of both species survived a wide range of soil moistures (≈ 0.5 to 90%), maintained for 3 mo. However, the eggs of the marsh grasshopper, R. microptera, better tolerated the highest soil moistures (95 and 100%), whereas the eggs of the desert species, T. eques, better tolerated the lowest soil moistures (0.0 and 0.1%). Sixty-five percent of marsh-inhabiting R. microptera eggs, but no desert T. eques eggs, survived 3 mo submersion under water. In contrast, 49% of desert T. eques eggs, but only 3.5% of R. microptera eggs, survived after being laid into oven-dried sand and then maintained with no additional water until hatch. In the laboratory at 26°C, the two species differed significantly in the mean length of the oviposition-to-hatch interval: 176 d for R. microptera versus 237 d for T. eques. These divergent traits presumably benefit these insects in their divergent habitats. Our results suggest the evolution of physiological divergence that is consistent with adaptations to local environments. PMID:22182625

  9. Divergent egg physiologies in two closely related grasshopper species: Taeniopoda eques versus Romalea microptera (Orthoptera: Romaleidae).

    PubMed

    Stauffer, Timothy W; Hatle, John D; Whitman, Douglas W

    2011-02-01

    We compared egg survivorship and egg development time at different soil moistures for two closely related grasshopper species from divergent habitats: marsh-inhabiting Romalea microptera (Beauvois) versus desert-inhabiting Taeniopoda eques (Burmeister). These two species can interbreed and produce viable offspring. In nature, both species have a similar 8-9 mo subterranean egg stage, but their soil environments differ dramatically in water content. We predicted that the eggs of the two species would exhibit differential survivorship and development times under different moisture levels. Our laboratory results show that the eggs of both species survived a wide range of soil moistures (≈ 0.5 to 90%), maintained for 3 mo. However, the eggs of the marsh grasshopper, R. microptera, better tolerated the highest soil moistures (95 and 100%), whereas the eggs of the desert species, T. eques, better tolerated the lowest soil moistures (0.0 and 0.1%). Sixty-five percent of marsh-inhabiting R. microptera eggs, but no desert T. eques eggs, survived 3 mo submersion under water. In contrast, 49% of desert T. eques eggs, but only 3.5% of R. microptera eggs, survived after being laid into oven-dried sand and then maintained with no additional water until hatch. In the laboratory at 26 °C, the two species differed significantly in the mean length of the oviposition-to-hatch interval: 176 d for R. microptera versus 237 d for T. eques. These divergent traits presumably benefit these insects in their divergent habitats. Our results suggest the evolution of physiological divergence that is consistent with adaptations to local environments. PMID:22182625

  10. Linking host prokaryotic physiology to viral lifestyle dynamics in a temperate freshwater lake (Lake Pavin, France).

    PubMed

    Palesse, S; Colombet, J; Pradeep Ram, A S; Sime-Ngando, T

    2014-11-01

    In aquatic ecosystems, fluctuations in environmental conditions and prokaryotic host physiological states can strongly affect the dynamics of viral life strategies. The influence of prokaryote physiology and environmental factors on viral replication cycles (lytic and lysogeny) was investigated from April to September 2011 at three different strata (epi, meta, and hypolimnion) in the mixolimnion of deep volcanic temperate freshwater Lake Pavin (France). Overall, the euphotic region (epi and metalimnion) was more dynamic and showed significant variation in microbial standing stocks, prokaryotic physiological state, and viral life strategies compared to the aphotic hypolimnion which was stable within sampled months. The prokaryotic host physiology as inferred from the nucleic acid content of prokaryotic cells (high or low nucleic acid) was strongly regulated by the chlorophyll concentration. The predominance of the high nucleic acid (HNA) prokaryotes (cells) over low nucleic acid (LNA) prokaryotes (cells) in the spring (HNA/LNA = 1.2) and vice versa in the summer period (HNA/LNA = 0.4) suggest that the natural prokaryotic communities underwent major shifts in their physiological states during investigated time period. The increase in the percentage of inducible lysogenic prokaryotes in the summer period was associated with the switch in the dominance of LNA over HNA cells, which coincided with the periods of strong resource (nutrient) limitation. This supports the idea that lysogeny represents a maintenance strategy for viruses in unproductive or harsh nutrient/host conditions. A negative correlation of percentage of lysogenic prokaryotes with HNA cell abundance and chlorophyll suggest that lysogenic cycle is closely related to prokaryotic cells which are stressed or starved due to unavailability of resources for its growth and activity. Our results provide support to previous findings that changes in prokaryote physiology are critical for the promotion and

  11. The Effects of Drought and Shade on the Performance, Morphology and Physiology of Ghanaian Tree Species

    PubMed Central

    Amissah, Lucy; Mohren, Godefridus M. J.; Kyereh, Boateng; Poorter, Lourens

    2015-01-01

    In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the “facilitation hypothesis” that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root

  12. The effects of drought and shade on the performance, morphology and physiology of Ghanaian tree species.

    PubMed

    Amissah, Lucy; Mohren, Godefridus M J; Kyereh, Boateng; Poorter, Lourens

    2015-01-01

    In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the "facilitation hypothesis" that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root

  13. Drought stress limits the geographic ranges of two tree species via different physiological mechanisms.

    PubMed

    Anderegg, Leander D L; HilleRisLambers, Janneke

    2016-03-01

    Range shifts are among the most ubiquitous ecological responses to anthropogenic climate change and have large consequences for ecosystems. Unfortunately, the ecophysiological forces that constrain range boundaries are poorly understood, making it difficult to mechanistically project range shifts. To explore the physiological mechanisms by which drought stress controls dry range boundaries in trees, we quantified elevational variation in drought tolerance and in drought avoidance-related functional traits of a widespread gymnosperm (ponderosa pine - Pinus ponderosa) and angiosperm (trembling aspen - Populus tremuloides) tree species in the southwestern USA. Specifically, we quantified tree-to-tree variation in growth, water stress (predawn and midday xylem tension), drought avoidance traits (branch conductivity, leaf/needle size, tree height, leaf area-to-sapwood area ratio), and drought tolerance traits (xylem resistance to embolism, hydraulic safety margin, wood density) at the range margins and range center of each species. Although water stress increased and growth declined strongly at lower range margins of both species, ponderosa pine and aspen showed contrasting patterns of clinal trait variation. Trembling aspen increased its drought tolerance at its dry range edge by growing stronger but more carbon dense branch and leaf tissues, implying an increased cost of growth at its range boundary. By contrast, ponderosa pine showed little elevational variation in drought-related traits but avoided drought stress at low elevations by limiting transpiration through stomatal closure, such that its dry range boundary is associated with limited carbon assimilation even in average climatic conditions. Thus, the same climatic factor (drought) may drive range boundaries through different physiological mechanisms - a result that has important implications for process-based modeling approaches to tree biogeography. Further, we show that comparing intraspecific patterns of

  14. The Role of Emotional Responses and Physiological Reactivity in the Marital Conflict-Child Functioning Link

    ERIC Educational Resources Information Center

    El-Sheikh, Mona

    2005-01-01

    Background: Children's emotional responses and physiological reactivity to conflict were examined as mediators and moderators in the associations between exposure to parental marital conflict and child adjustment and cognitive problems. Method: One hundred and eighty elementary school children participated. In response to a simulated argument,…

  15. Invariance in current dipole moment density across brain structures and species: Physiological constraint for neuroimaging

    PubMed Central

    Murakami, Shingo; Okada, Yoshio

    2015-01-01

    Although anatomical constraints have been shown to be effective for MEG and EEG inverse solutions, there are still no effective physiological constraints. Strength of the current generator is normally described by the moment of an equivalent current dipole Q. This value is quite variable since it depends on size of active tissue. In contrast, the current dipole moment density q, defined as Q per surface area of active cortex, is independent of size of active tissue. Here we studied whether the value of q has a maximum in physiological conditions across brain structures and species. We determined the value due to the primary neuronal current (qprimary) alone, correcting for distortions due to measurement conditions and secondary current sources at boundaries separating regions of differing electrical conductivity. The values were in the same range for turtle cerebellum (0.56–1.48 nAm/mm2), guinea pig hippocampus (0.30–1.34 nAm/mm2), and swine neocortex (0.18–1.63 nAm/mm2), rat neocortex (~2.2 nAm/mm2), monkey neocortex (~0.40 nAm/mm2) and human neocortex (0.16–0.77 nAm/mm2). Thus, there appears to be a maximum value across the brain structures and species (1–2 nAm/mm2). The empirical values closely matched the theoretical values obtained with our independently validated neural network model (1.6–2.8 nAm/mm2 for initial spike and 0.7–3.1 nAm/mm2 for burst), indicating that the apparent invariance is not coincidental. Our model study shows that a single maximum value may exist across a wide range of brain structures and species, varying in neuron density, due to fundamental electrical properties of neurons. The maximum value of qprimary may serve as an effective physiological constraint for MEG/EEG inverse solutions. PMID:25680520

  16. Environmental physiology of three species of Collembola at Cape Hallett, North Victoria Land, Antarctica.

    PubMed

    Sinclair, Brent J; Terblanche, John S; Scott, Matthew B; Blatch, Gregory L; Jaco Klok, C; Chown, Steven L

    2006-01-01

    The environmental physiology of three speciesof Collembola: Cryptopygus cisantarcticus, Isotoma klovstadi (Isotomidae) and Friesea grisea (Neanuridae) was investigated from November 2002 to February 2003 at Cape Hallett, North Victoria Land, Antarctica. All three species were freeze avoiding, and while supercooling points were variable on seasonal and daily scales in I. klovstadi and C. cisantarcticus, they remained largely static in F. grisea. LT50 (temperature where 50% of animals are killed by cold) was -13.6, -19.1 and -19.8 degrees C for C. cisantarcticus, I. klovstadi and F. grisea, respectively. Upper lethal temperature was 34, 34 and 38 degrees C for C. cisantarcticus, I. klovstadi and F. grisea. Critical thermal minimum onset (the temperature where individuals entered chill coma) was ca. -7, -12 and -8 degrees C for C. cisantarcticus, I. klovstadi and F. grisea, and 25% of I. klovstadi individuals froze without entering chill coma. Critical thermal maximum (the onset of spasms at high temperature) was 30, 33 and 34 degrees C for C. cisantarcticus, I. klovstadi and F. grisea. Haemolymph osmolality was approximately 720 mOsm for C. cisantarcticus and 680 mOsm for I. klovstadi, and both species showed a moderate degree of thermal hysteresis, which persisted through the season. Desiccation resistance was measured as survival above silica gel, and the species survived in the rank order of C. cisantarcticus< I. klovstadi = F. grisea. Desiccation resulted in an increase in haemolymph osmolality in I. klovstadi, and water was quickly regained by desiccation-stressed individuals that had access to liquid water, but not by individuals placed in high humidity, indicating that this species is unable to absorb atmospheric water vapour. SDS-PAGE did not suggest any strong patterns in protein synthesis either seasonally or in response to temperature or desiccation stress. Microclimate temperatures were measured at sites representative of collection sites for the three

  17. Physiological Responses to Prolonged Drought Differ Among Three Oak (Quercus) Species

    NASA Astrophysics Data System (ADS)

    Cooper, C. E.; Moore, G. W.; Vogel, J. G.; Muir, J. P.

    2015-12-01

    The physiological response of plants to water stress provides insights into which species may survive in exceptional drought conditions. This study conducted on a remnant post oak savanna site in College Station, Texas, examined how drought affected the physiology of three native oak species. In June 2014, after a period of equal watering, we subjected three year old Quercus shumardii (Shumard oak; SO), Q. virginiana (live oak; LO), and Q. macrocarpa (bur oak; BO) saplings to one of two watering treatments: 1) watered, receiving the equivalent of theaverage precipitation rate and 2) droughted, receiving a 100% reduction in precipitation. We measured predawn (ΨPD) and midday (ΨMD) leaf water potential; midday gas exchange (MGE) parameters including photosynthesis (Al), transpiration (T), stomatal conductance (gsw); and leaf soluble (SS) and non-soluble sugar (NSS) concentrations monthly between June and October 2014. Drought stress responses were evident after only one month of induced drought. Droughted saplings showed reduced ΨPD, ΨMD, and MGE (P ≤ 0.05) in comparison to watered saplings of the same species. LO saplings exhibited greater MGE (P ≤ 0.05) while maintaining similar LWP to their respective watered and droughted BO and SO counterparts. Droughted LO exhibited MGE rates similar to those of watered BO and SO (P ≤ 0.05), while watered LO adjusted its MGE rates to changes in water availability better than BO and LO during short-term drought. Compared to water saplings, droughted saplings had greater leaf SS (P = 0.08) and lower NSS concentrations (P = 0.10), possibly due to the conversion of NSS to SS and other simple compounds and reduced consumption of SS for growth by the droughted saplings. Although SO and BO exhibited similar photosynthesis rates, leaf total sugar (SS+NSS) concentration was greater in SO (P ≤ 0.05). By displaying the greatest average photosynthesis rate (P ≤ 0.05), LO should have accumulated the greatest amount of carbon

  18. Physiological inputs regulate species-specific anatomy during embryogenesis and regeneration

    PubMed Central

    Sullivan, Kelly G.; Emmons-Bell, Maya; Levin, Michael

    2016-01-01

    ABSTRACT A key problem in evolutionary developmental biology is identifying the sources of instructive information that determine species-specific anatomical pattern. Understanding the inputs to large-scale morphology is also crucial for efforts to manipulate pattern formation in regenerative medicine and synthetic bioengineering. Recent studies have revealed a physiological system of communication among cells that regulates pattern during embryogenesis and regeneration in vertebrate and invertebrate models. Somatic tissues form networks using the same ion channels, electrical synapses, and neurotransmitter mechanisms exploited by the brain for information-processing. Experimental manipulation of these circuits was recently shown to override genome default patterning outcomes, resulting in head shapes resembling those of other species in planaria and Xenopus. The ability to drastically alter macroscopic anatomy to that of other extant species, despite a wild-type genomic sequence, suggests exciting new approaches to the understanding and control of patterning. Here, we review these results and discuss hypotheses regarding non-genomic systems of instructive information that determine biological growth and form. PMID:27574538

  19. Physiological inputs regulate species-specific anatomy during embryogenesis and regeneration.

    PubMed

    Sullivan, Kelly G; Emmons-Bell, Maya; Levin, Michael

    2016-01-01

    A key problem in evolutionary developmental biology is identifying the sources of instructive information that determine species-specific anatomical pattern. Understanding the inputs to large-scale morphology is also crucial for efforts to manipulate pattern formation in regenerative medicine and synthetic bioengineering. Recent studies have revealed a physiological system of communication among cells that regulates pattern during embryogenesis and regeneration in vertebrate and invertebrate models. Somatic tissues form networks using the same ion channels, electrical synapses, and neurotransmitter mechanisms exploited by the brain for information-processing. Experimental manipulation of these circuits was recently shown to override genome default patterning outcomes, resulting in head shapes resembling those of other species in planaria and Xenopus. The ability to drastically alter macroscopic anatomy to that of other extant species, despite a wild-type genomic sequence, suggests exciting new approaches to the understanding and control of patterning. Here, we review these results and discuss hypotheses regarding non-genomic systems of instructive information that determine biological growth and form. PMID:27574538

  20. Transcriptome profiles link environmental variation and physiological response of Mytilus californianus between Pacific tides

    PubMed Central

    Place, Sean P.; Menge, Bruce A.; Hofmann, Gretchen E.

    2011-01-01

    Summary The marine intertidal zone is characterized by large variation in temperature, pH, dissolved oxygen and the supply of nutrients and food on seasonal and daily time scales. These oceanic fluctuations drive of ecological processes such as recruitment, competition and consumer-prey interactions largely via physiological mehcanisms. Thus, to understand coastal ecosystem dynamics and responses to climate change, it is crucial to understand these mechanisms. Here we utilize transcriptome analysis of the physiological response of the mussel Mytilus californianus at different spatial scales to gain insight into these mechanisms. We used mussels inhabiting different vertical locations within Strawberry Hill on Cape Perpetua, OR and Boiler Bay on Cape Foulweather, OR to study inter- and intra-site variation of gene expression. The results highlight two distinct gene expression signatures related to the cycling of metabolic activity and perturbations to cellular homeostasis. Intermediate spatial scales show a strong influence of oceanographic differences in food and stress environments between sites separated by ~65 km. Together, these new insights into environmental control of gene expression may allow understanding of important physiological drivers within and across populations. PMID:22563136

  1. Mitochondrial physiology and reactive oxygen species production are altered by hypoxia acclimation in killifish (Fundulus heteroclitus).

    PubMed

    Du, Sherry N N; Mahalingam, Sajeni; Borowiec, Brittney G; Scott, Graham R

    2016-04-15

    Many fish encounter hypoxia in their native environment, but the role of mitochondrial physiology in hypoxia acclimation and hypoxia tolerance is poorly understood. We investigated the effects of hypoxia acclimation on mitochondrial respiration, O2kinetics, emission of reactive oxygen species (ROS), and antioxidant capacity in the estuarine killifish ( ITALIC! Fundulus heteroclitus). Killifish were acclimated to normoxia, constant hypoxia (5 kPa O2) or intermittent diel cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia) for 28-33 days and mitochondria were isolated from liver. Neither pattern of hypoxia acclimation affected the respiratory capacities for oxidative phosphorylation or electron transport, leak respiration, coupling control or phosphorylation efficiency. Hypoxia acclimation also had no effect on mitochondrial O2kinetics, but ITALIC! P50(the O2tension at which hypoxia inhibits respiration by 50%) was lower in the leak state than during maximal respiration, and killifish mitochondria endured anoxia-reoxygenation without any impact on mitochondrial respiration. However, both patterns of hypoxia acclimation reduced the rate of ROS emission from mitochondria when compared at a common O2tension. Hypoxia acclimation also increased the levels of protein carbonyls and the activities of superoxide dismutase and catalase in liver tissue (the latter only occurred in constant hypoxia). Our results suggest that hypoxia acclimation is associated with changes in mitochondrial physiology that decrease ROS production and may help improve hypoxia tolerance. PMID:26896545

  2. Frost hardiness in walnut trees (Juglans regia L.): how to link physiology and modelling?

    PubMed

    Charrier, Guillaume; Poirier, Magalie; Bonhomme, Marc; Lacointe, André; Améglio, Thierry

    2013-11-01

    In the literature, frost hardiness (FH) studies in trees have often been restricted to one organ (buds, leaves, needles or twigs). To extend our knowledge and gain a unified view, FH differences between organs and tissues or throughout the life of the tree have to be characterized in relation to physiological changes. In this study, different organs and tissues of young potted and mature orchard walnut trees (Juglans regia L.) were compared for seasonal changes in FH during different years. FH was assessed using the electrolyte leakage method. Physiological parameters were concomitantly monitored focusing on two significant traits: water content (WC) and carbohydrate content (glucose + fructose + sucrose, GFS). No seasonal variation in FH was observed in the root system, but acclimation and deacclimation were observed aboveground. Among organs and tissues, cold sensitivity levels were different in deep winter, with buds most sensitive and bark most resistant, but acclimation/deacclimation dynamics followed similar patterns. Physiological variation was also similar among organs: FH increased when WC decreased and/or soluble carbohydrates increased. Based on these results, relations between soluble carbohydrate content, WC and FH were calculated independently or in interaction. The key results were that: (i) the relationship between FH and physiological parameters (GFS and WC), which had previously been shown for branches only, could be generalized to all aboveground organs; (ii) lower WC increased the cryoprotective effect of GFS, showing a synergic effect of the two factors; (iii) the best fit was a non-linear function of WC and GFS, yielding a predictive model with an root mean square error of 5.07 °C on an independent dataset and 2.59 °C for the most sensitive stages; and (iv) the same parameters used for all organs yielded a unified model of FH depending on physiology, although the variability of GFS or WC was wide. The model should be of value for predicting

  3. Physiological Arousal in Autism and Fragile X Syndrome: Group Comparisons and Links with Pragmatic Language

    ERIC Educational Resources Information Center

    Klusek, Jessica; Martin, Gary E.; Losh, Molly

    2013-01-01

    This study tested the hypothesis that pragmatic (i.e., social) language impairment is linked to arousal dysregulation in autism spectrum disorder (ASD) and fragile X syndrome (FXS). Forty boys with ASD, 39 with FXS, and 27 with typical development (TD), aged 4-15 years, participated. Boys with FXS were hyperaroused compared to boys with TD but did…

  4. Invasive insect effects on nitrogen cycling and host physiology are not tightly linked.

    PubMed

    Rubino, Lucy; Charles, Sherley; Sirulnik, Abby G; Tuininga, Amy R; Lewis, James D

    2015-02-01

    Invasive insects may dramatically alter resource cycling and productivity in forest ecosystems. Yet, although responses of individual trees should both reflect and affect ecosystem-scale responses, relationships between physiological- and ecosystem-scale responses to invasive insects have not been extensively studied. To address this issue, we examined changes in soil nitrogen (N) cycling, N uptake and allocation, and needle biochemistry and physiology in eastern hemlock (Tsuga canadensis (L) Carr) saplings, associated with infestation by the hemlock woolly adelgid (HWA) (Adelges tsugae Annand), an invasive insect causing widespread decline of eastern hemlock in the eastern USA. Compared with uninfested saplings, infested saplings had soils that exhibited faster nitrification rates, and more needle (15)N uptake, N and total protein concentrations. However, these variables did not clearly covary. Further, within infested saplings, needle N concentration did not vary with HWA density. Light-saturated net photosynthetic rates (Asat) declined by 42% as HWA density increased from 0 to 3 adelgids per needle, but did not vary with needle N concentration. Rather, Asat varied with stomatal conductance, which was highest at the lowest HWA density and accounted for 79% of the variation in Asat. Photosynthetic light response did not differ among HWA densities. Our results suggest that the effects of HWA infestation on soil N pools and fluxes, (15)N uptake, needle N and protein concentrations, and needle physiology may not be tightly coupled under at least some conditions. This pattern may reflect direct effects of the HWA on N uptake by host trees, as well as effects of other scale-dependent factors, such as tree hydrology, affected by HWA activity. PMID:25721368

  5. Determining the Effect of Natural Selection on Linked Neutral Divergence across Species

    PubMed Central

    Phung, Tanya N.; Lohmueller, Kirk E.

    2016-01-01

    A major goal in evolutionary biology is to understand how natural selection has shaped patterns of genetic variation across genomes. Studies in a variety of species have shown that neutral genetic diversity (intra-species differences) has been reduced at sites linked to those under direct selection. However, the effect of linked selection on neutral sequence divergence (inter-species differences) remains ambiguous. While empirical studies have reported correlations between divergence and recombination, which is interpreted as evidence for natural selection reducing linked neutral divergence, theory argues otherwise, especially for species that have diverged long ago. Here we address these outstanding issues by examining whether natural selection can affect divergence between both closely and distantly related species. We show that neutral divergence between closely related species (e.g. human-primate) is negatively correlated with functional content and positively correlated with human recombination rate. We also find that neutral divergence between distantly related species (e.g. human-rodent) is negatively correlated with functional content and positively correlated with estimates of background selection from primates. These patterns persist after accounting for the confounding factors of hypermutable CpG sites, GC content, and biased gene conversion. Coalescent models indicate that even when the contribution of ancestral polymorphism to divergence is small, background selection in the ancestral population can still explain a large proportion of the variance in divergence across the genome, generating the observed correlations. Our findings reveal that, contrary to previous intuition, natural selection can indirectly affect linked neutral divergence between both closely and distantly related species. Though we cannot formally exclude the possibility that the direct effects of purifying selection drive some of these patterns, such a scenario would be possible only

  6. Determining the Effect of Natural Selection on Linked Neutral Divergence across Species.

    PubMed

    Phung, Tanya N; Huber, Christian D; Lohmueller, Kirk E

    2016-08-01

    A major goal in evolutionary biology is to understand how natural selection has shaped patterns of genetic variation across genomes. Studies in a variety of species have shown that neutral genetic diversity (intra-species differences) has been reduced at sites linked to those under direct selection. However, the effect of linked selection on neutral sequence divergence (inter-species differences) remains ambiguous. While empirical studies have reported correlations between divergence and recombination, which is interpreted as evidence for natural selection reducing linked neutral divergence, theory argues otherwise, especially for species that have diverged long ago. Here we address these outstanding issues by examining whether natural selection can affect divergence between both closely and distantly related species. We show that neutral divergence between closely related species (e.g. human-primate) is negatively correlated with functional content and positively correlated with human recombination rate. We also find that neutral divergence between distantly related species (e.g. human-rodent) is negatively correlated with functional content and positively correlated with estimates of background selection from primates. These patterns persist after accounting for the confounding factors of hypermutable CpG sites, GC content, and biased gene conversion. Coalescent models indicate that even when the contribution of ancestral polymorphism to divergence is small, background selection in the ancestral population can still explain a large proportion of the variance in divergence across the genome, generating the observed correlations. Our findings reveal that, contrary to previous intuition, natural selection can indirectly affect linked neutral divergence between both closely and distantly related species. Though we cannot formally exclude the possibility that the direct effects of purifying selection drive some of these patterns, such a scenario would be possible only

  7. Weather and Death on Mount Everest: Is there a link between Storms and Human Physiology?

    NASA Astrophysics Data System (ADS)

    Moore, K.; Semple, J.

    2004-05-01

    Scientific interest in Mount Everest has been largely focused on the hypoxia caused by the summit's low barometric pressure. Although weather is recognized as a significant risk factor, it has not been extensively studied. Through the use of observations made at the mountain's South Col, elevation 7986m, and other datasets, we show that high impact weather events on Mount Everest, including the May 1996 storm in which 8 climbers perished, are often associated with continental-scale intrusions of stratospheric air into the upper-troposphere. The variability in wind speeds associated with these intrusions triggered convective activity that resulted in the high impact weather. In addition, the validation of existing meteorological data allows for useful insights into the possibility of forecasting these high impact weather events and their physiological impacts thereby mitigating deaths that occur on the exposed upper slopes of Mount Everest.

  8. Linking physiological approaches to marine vertebrate conservation: using sex steroid hormone determinations in demographic assessments

    PubMed Central

    Labrada-Martagón, Vanessa; Zenteno-Savín, Tania; Mangel, Marc

    2014-01-01

    Sex, age and sexual maturation are key biological parameters for aspects of life history and are fundamental information for assessing demographic changes and the reproductive viability and performance of natural populations under exploitation pressures or in response to environmental influences. Much of the information available on the reproductive condition, length at sexual maturity and sex determinations of endangered species has been derived from direct examination of the gonads in dead animals, either intentionally or incidentally caught, or from stranded individuals. However, morphological data, when used alone, do not provide accurate demographic information in sexually monomorphic marine vertebrate species (e.g. sharks, sea turtles, seabirds and cetaceans). Hormone determination is an accurate and non-destructive method that provides indirect information about sex, reproductive condition and sexual maturity of free-ranging individuals. Correlations between sex steroid concentrations and biochemical parameters, gonadal development and state, reproductive behaviour and secondary external features have been already demonstrated in many species. Different non-lethal approaches (e.g. surgical and mark–recapture procedures), with intrinsic advantages and disadvantages when applied on free-ranging organisms, have been proposed to asses sex, growth and reproductive condition. Hormone determination from blood samples will generate valuable additional demographic information needed for stock assessment and biological conservation. PMID:27293619

  9. PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Uterine infection: linking infection and innate immunity with infertility in the high-producing dairy cow.

    PubMed

    Bromfield, J J; Santos, J E P; Block, J; Williams, R S; Sheldon, I M

    2015-05-01

    Uterine contamination with bacteria is ubiquitous in the postpartum dairy cow. Nearly one-half of all postpartum dairy cows develop clinical disease resulting in metritis and endometritis, which cause depressed milk production and infertility. The causative links between uterine infection and infertility include a hostile uterine environment, disrupted endocrine signaling, and perturbations in ovarian function and oocyte development. In this review we consider the various mechanisms linking uterine infection with infertility in the dairy cow, specifically 1) innate immune signaling in the endometrium, 2) alteration in endocrine signaling in response to infectious agents, and 3) impacts of infection on ovarian function, oocyte development, and follicular development. Normal ovarian follicular and oocyte development requires a series of temporally and spatially orchestrated events; however, several of the cellular pathways required for ovarian function are also used during the innate immune response to bacterial pathogens. We propose that activation of cellular pathways during this immune response has a negative impact on ovarian physiology, which is manifest as infertility detected after the clearance of the bacteria. This review highlights how new insights into infection and immunity in cattle are linked to infertility. PMID:26020298

  10. Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter

    PubMed Central

    Schmitz, Oswald J.; Bradford, Mark A.; Strickland, Michael S.; Hawlena, Dror

    2013-01-01

    The quantity and quality of detritus entering the soil determines the rate of decomposition by microbial communities as well as recycle rates of nitrogen (N) and carbon (C) sequestration1,2. Plant litter comprises the majority of detritus3, and so it is assumed that decomposition is only marginally influenced by biomass inputs from animals such as herbivores and carnivores4,5. However, carnivores may influence microbial decomposition of plant litter via a chain of interactions in which predation risk alters the physiology of their herbivore prey that in turn alters soil microbial functioning when the herbivore carcasses are decomposed6. A physiological stress response by herbivores to the risk of predation can change the C:N elemental composition of herbivore biomass7,8,9 because stress from predation risk increases herbivore basal energy demands that in nutrient-limited systems forces herbivores to shift their consumption from N-rich resources to support growth and reproduction to C-rich carbohydrate resources to support heightened metabolism6. Herbivores have limited ability to store excess nutrients, so stressed herbivores excrete N as they increase carbohydrate-C consumption7. Ultimately, prey stressed by predation risk increase their body C:N ratio7,10, making them poorer quality resources for the soil microbial pool likely due to lower availability of labile N for microbial enzyme production6. Thus, decomposition of carcasses of stressed herbivores has a priming effect on the functioning of microbial communities that decreases subsequent ability to of microbes to decompose plant litter6,10,11. We present the methodology to evaluate linkages between predation risk and litter decomposition by soil microbes. We describe how to: induce stress in herbivores from predation risk; measure those stress responses, and measure the consequences on microbial decomposition. We use insights from a model grassland ecosystem comprising the hunting spider predator (Pisuarina

  11. Linking Subcellular Disturbance to Physiological Behavior and Toxicity Induced by Quantum Dots in Caenorhabditis elegans.

    PubMed

    Wang, Qin; Zhou, Yanfeng; Song, Bin; Zhong, Yiling; Wu, Sicong; Cui, Rongrong; Cong, Haixia; Su, Yuanyuan; Zhang, Huimin; He, Yao

    2016-06-01

    The wide-ranging applications of fluorescent semiconductor quantum dots (QDs) have triggered increasing concerns about their biosafety. Most QD-related toxicity studies focus on the subcellular processes in cultured cells or global physiological effects on whole animals. However, it is unclear how QDs affect subcellular processes in living organisms, or how the subcellular disturbance contributes to the overall toxicity. Here the behavior and toxicity of QDs of three different sizes in Caenorhabditis elegans (C. elegans) are systematically investigated at both the systemic and the subcellular level. Specifically, clear size-dependent distribution and toxicity of the QDs in the digestive tract are observed. Short-term exposure of QDs leads to acute toxicity on C. elegans, yet incurring no lasting, irreversible damage. In contrast, chronic exposure of QDs severely inhibits development and shortens lifespan. Subcellular analysis reveals that endocytosis and nutrition storage are disrupted by QDs, which likely accounts for the severe deterioration in growth and longevity. This work reveals that QDs invasion disrupts key subcellular processes in living organisms, and may cause permanent damage to the tissues and organs over long-term retention. The findings provide invaluable information for safety evaluations of QD-based applications and offer new opportunities for design of novel nontoxic nanoprobes. PMID:27121203

  12. Stochastic dynamic programming illuminates the link between environment, physiology, and evolution.

    PubMed

    Mangel, Marc

    2015-05-01

    I describe how stochastic dynamic programming (SDP), a method for stochastic optimization that evolved from the work of Hamilton and Jacobi on variational problems, allows us to connect the physiological state of organisms, the environment in which they live, and how evolution by natural selection acts on trade-offs that all organisms face. I first derive the two canonical equations of SDP. These are valuable because although they apply to no system in particular, they share commonalities with many systems (as do frictionless springs). After that, I show how we used SDP in insect behavioral ecology. I describe the puzzles that needed to be solved, the SDP equations we used to solve the puzzles, and the experiments that we used to test the predictions of the models. I then briefly describe two other applications of SDP in biology: first, understanding the developmental pathways followed by steelhead trout in California and second skipped spawning by Norwegian cod. In both cases, modeling and empirical work were closely connected. I close with lessons learned and advice for the young mathematical biologists. PMID:25033778

  13. Fisheries conservation on the high seas: linking conservation physiology and fisheries ecology for the management of large pelagic fishes.

    PubMed

    Horodysky, Andrij Z; Cooke, Steven J; Graves, John E; Brill, Richard W

    2016-01-01

    Populations of tunas, billfishes and pelagic sharks are fished at or over capacity in many regions of the world. They are captured by directed commercial and recreational fisheries (the latter of which often promote catch and release) or as incidental catch or bycatch in commercial fisheries. Population assessments of pelagic fishes typically incorporate catch-per-unit-effort time-series data from commercial and recreational fisheries; however, there have been notable changes in target species, areas fished and depth-specific gear deployments over the years that may have affected catchability. Some regional fisheries management organizations take into account the effects of time- and area-specific changes in the behaviours of fish and fishers, as well as fishing gear, to standardize catch-per-unit-effort indices and refine population estimates. However, estimates of changes in stock size over time may be very sensitive to underlying assumptions of the effects of oceanographic conditions and prey distribution on the horizontal and vertical movement patterns and distribution of pelagic fishes. Effective management and successful conservation of pelagic fishes requires a mechanistic understanding of their physiological and behavioural responses to environmental variability, potential for interaction with commercial and recreational fishing gear, and the capture process. The interdisciplinary field of conservation physiology can provide insights into pelagic fish demography and ecology (including environmental relationships and interspecific interactions) by uniting the complementary expertise and skills of fish physiologists and fisheries scientists. The iterative testing by one discipline of hypotheses generated by the other can span the fundamental-applied science continuum, leading to the development of robust insights supporting informed management. The resulting species-specific understanding of physiological abilities and tolerances can help to improve stock

  14. Fisheries conservation on the high seas: linking conservation physiology and fisheries ecology for the management of large pelagic fishes

    PubMed Central

    Horodysky, Andrij Z.; Cooke, Steven J.; Graves, John E.; Brill, Richard W.

    2016-01-01

    Populations of tunas, billfishes and pelagic sharks are fished at or over capacity in many regions of the world. They are captured by directed commercial and recreational fisheries (the latter of which often promote catch and release) or as incidental catch or bycatch in commercial fisheries. Population assessments of pelagic fishes typically incorporate catch-per-unit-effort time-series data from commercial and recreational fisheries; however, there have been notable changes in target species, areas fished and depth-specific gear deployments over the years that may have affected catchability. Some regional fisheries management organizations take into account the effects of time- and area-specific changes in the behaviours of fish and fishers, as well as fishing gear, to standardize catch-per-unit-effort indices and refine population estimates. However, estimates of changes in stock size over time may be very sensitive to underlying assumptions of the effects of oceanographic conditions and prey distribution on the horizontal and vertical movement patterns and distribution of pelagic fishes. Effective management and successful conservation of pelagic fishes requires a mechanistic understanding of their physiological and behavioural responses to environmental variability, potential for interaction with commercial and recreational fishing gear, and the capture process. The interdisciplinary field of conservation physiology can provide insights into pelagic fish demography and ecology (including environmental relationships and interspecific interactions) by uniting the complementary expertise and skills of fish physiologists and fisheries scientists. The iterative testing by one discipline of hypotheses generated by the other can span the fundamental–applied science continuum, leading to the development of robust insights supporting informed management. The resulting species-specific understanding of physiological abilities and tolerances can help to improve stock

  15. Physiological Arousal in Autism and Fragile X Syndrome: Group Comparisons and Links With Pragmatic Language

    PubMed Central

    Klusek, Jessica; Martin, Gary E.; Losh, Molly

    2014-01-01

    This study tested the hypothesis that pragmatic (i.e., social) language impairment is linked to arousal dysregulation in autism spectrum disorder (ASD) and fragile X syndrome (FXS). Forty boys with ASD, 39 with FXS, and 28 with typical development (TD), aged 4–15 years, participated. Boys with FXS were hyperaroused compared to boys with TD but did not differ from boys with ASD. Dampened vagal tone predicted pragmatic impairment in ASD, and associations emerged between cardiac activity and receptive/expressive vocabulary across groups. Findings support autonomic dysfunction as a mechanism underlying pragmatic impairment in ASD and suggest that biophysiological profiles are shared in ASD and FXS, which has implications for understanding the role of fragile X mental retardation-1 (FMR1, the FXS gene) in the pathophysiology of ASD. PMID:24432860

  16. Chronic exposure to soil salinity in terrestrial species: Does plasticity and underlying physiology differ among specialized ground-dwelling spiders?

    PubMed

    Renault, D; Puzin, C; Foucreau, N; Bouchereau, A; Pétillon, J

    2016-07-01

    In salt marshes, the alternation of low and high tides entails rapid shifts of submersion and aerial exposure for terrestrial communities. In these intertidal environments, terrestrial species have to deal with an osmotic loss in body water content and an increase in sodium chloride concentration when salt load increases. In salt marshes, spiders represent an abundant arthropod group, whose physiological ecology in response to variations of soil salinity must be further investigated. In this study, we compared the effect of salinity on the survival and physiology of three species of Lycosidae; two salt marsh species (Arctosa fulvolineata and Pardosa purbeckensis) and one forest species (P. saltans). Spiders were individually exposed at three salinity conditions (0‰, 35‰ and 70‰) and survival, changes in body water content, hemolymph ions (Na(+), Ca(2+), Mg(2+), K(+); ICP-MS technique) and metabolites (mainly amino acids, polyols, sugars; LC and GC techniques) were assessed. The survival of the forest species P. saltans was very quickly hampered at moderate and high salinities. In this spider, variations of hemolymph ions and metabolites revealed a quick loss of physiological homeostasis and a rapid salt-induced dehydration of the specimens. Conversely, high survival durations were measured in the two salt-marsh spiders, and more particularly in A. fulvolineata. In both P. purbeckensis and A. fulvolineata, the proportion of Na(+), Ca(2+), Mg(2+), K(+) remained constant at the three experimental conditions. Accumulation of hemolymph Na(+) and amino acids (mainly glutamine and proline) demonstrated stronger osmoregulatory capacities in these salt-marsh resident spiders. To conclude, even if phylogenetically close (belonging to the same, monophyletic, family), we found different physiological capacities to cope with salt load among the three tested spider species. Nevertheless, physiological responses to salinity were highly consistent with the realized

  17. Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

    USGS Publications Warehouse

    Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph

    2015-01-01

    Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

  18. Crystal Structure of Human Senescence Marker Protein 30: Insights Linking Structural, Enzymatic, and Physiological Functions

    SciTech Connect

    Chakraborti, Subhendu; Bahnson, Brian J.

    2010-05-25

    Human senescence marker protein 30 (SMP30), which functions enzymatically as a lactonase, hydrolyzes various carbohydrate lactones. The penultimate step in vitamin-C biosynthesis is catalyzed by this enzyme in nonprimate mammals. It has also been implicated as an organophosphate hydrolase, with the ability to hydrolyze diisopropyl phosphofluoridate and other nerve agents. SMP30 was originally identified as an aging marker protein, whose expression decreased androgen independently in aging cells. SMP30 is also referred to as regucalcin and has been suggested to have functions in calcium homeostasis. The crystal structure of the human enzyme has been solved from X-ray diffraction data collected to a resolution of 1.4 {angstrom}. The protein has a 6-bladed {beta}-propeller fold, and it contains a single metal ion. Crystal structures have been solved with the metal site bound with either a Ca{sup 2+} or a Zn{sup 2+} atom. The catalytic role of the metal ion has been confirmed by mutagenesis of the metal coordinating residues. Kinetic studies using the substrate gluconolactone showed a k{sub cat} preference of divalent cations in the order Zn{sup 2+} > Mn{sup 2+} > Ca{sup 2+} > Mg{sup 2+}. Notably, the Ca{sup 2+} had a significantly higher value of K{sub d} compared to those of the other metal ions tested (566, 82, 7, and 0.6 {micro}m for Ca{sup 2+}, Mg{sup 2+}, Zn{sup 2+}, and Mn{sup 2+}, respectively), suggesting that the Ca{sup 2+}-bound form may be physiologically relevant for stressed cells with an elevated free calcium level.

  19. Surgically increased ovarian mass in the honey bee confirms link between reproductive physiology and worker behavior.

    PubMed

    Wang, Ying; Kaftanoglu, Osman; Siegel, Adam J; Page, Robert E; Amdam, Gro V

    2010-12-01

    Honey bee (Apis mellifera L.) workers are essentially sterile females that are used to study how complex social behavior develops. Workers perform nest tasks, like nursing larvae, prior to field tasks, like foraging. Despite worker sterility, this behavioral progression correlates with ovary size: workers with larger ovaries (many ovary filaments) start foraging at younger ages on average. It is untested, however, whether the correlation confers a causal relationship between ovary size and behavioral development. Here, we successfully grafted supernumerary ovaries into worker bees to produce an artificial increase in the amount of ovary tissue. We next measured fat body mRNA levels for the yolk precursor gene vitellogenin, which influences honey bee behavioral development and can correlate with ovary size. Vitellogenin was equally expressed in surgical controls and bees with supernumerary ovaries, leading us to predict that these groups would be characterized by equal behavior. Contrary to our prediction, bees with supernumerary ovaries showed accelerated behavioral development compared to surgical controls, which behaved like reference bees that were not treated surgically. To explore this result we monitored fat body expression levels of a putative ecdysteroid-response gene, HR46, which is genetically linked to ovary size in workers. Our data establish that social insect worker behavior can be directly influenced by ovaries, and that HR46 expression changes with ovary size independent of vitellogenin. PMID:20688074

  20. Sun-induced fluorescence of phytoplankton in the ocean: Linking physiology and remote sensing

    NASA Astrophysics Data System (ADS)

    Huot, Yannick

    non-photochemical quenching, damage and repair of photosystem II (PSII), acclimation of the antenna size of PSII, the ratio of photoprotective to photosynthetic pigments, and nutrient limitation. The results of this thesis should allow better retrieval and interpretation of the physiological and taxonomic information contained in sun-induced fluorescence.

  1. Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology.

    PubMed

    Wagai, Rota; Kishimoto-Mo, Ayaka W; Yonemura, Seiichiro; Shirato, Yasuhito; Hiradate, Syuntaro; Yagasaki, Yasumi

    2013-04-01

    Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (<1.6 and 1.6-1.8 g cm(-3) ) and bulk soil was measured by solid-state (13) C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for

  2. Comparison of immunodiffusion and enzyme linked immunosorbent assay for antibodies to four Aspergillus species.

    PubMed Central

    Froudist, J H; Harnett, G B; McAleer, R

    1989-01-01

    Antigenic extracts were prepared from Aspergillus fumigatus, A niger, A flavus and A terreus for use in enzyme linked immunosorbent assay (ELISA) and immunodiffusion (ID) tests for Aspergillus antibodies to determine whether the use of antigenic extracts from species other than A fumigatus increased the sensitivity of the ELISA. ELISA titres correlated well with positive ID tests. Patient titres by ELISA were significantly higher than control titres for all species. Patient titres to A niger were also significantly higher than titres to the other species. Total number of ID bands to A fumigatus correlated significantly with anti-A fumigatus ELISA titres. It is concluded that the use of antigenic extracts from species other than A fumigatus improves the sensitivity of the ELISA. PMID:2511230

  3. Effects of Arbuscular-Mycorrhizal Glomus Species on Drought Tolerance: Physiological and Nutritional Plant Responses

    PubMed Central

    Ruiz-Lozano, J. M.; Azcon, R.; Gomez, M.

    1995-01-01

    The tolerance of lettuce plants (Lactuca sativa L. cv. Romana) to drought stress differed with the arbuscular-mycorrhizal fungal isolate with which the plants were associated. Seven fungal species belonging to the genus Glomus were studied for their ability to enhance the drought tolerance of lettuce plants. These fungi had different traits that affected the drought resistance of host plants. The ranking of arbuscular-mycorrhizal fungal effects on drought tolerance, based on the relative decreases in shoot dry weight, was as follows: Glomus deserticola > Glomus fasciculatum > Glomus mosseae > Glomus etunicatum > Glomus intraradices > Glomus caledonium > Glomus occultum. In this comparative study specific mycorrhizal fungi had consistent effects on plant growth, mineral uptake, the CO(inf2) exchange rate, water use efficiency, transpiration, stomatal conductance, photosynthetic phosphorus use efficiency, and proline accumulation under either well-watered or drought-stressed conditions. The ability of the isolates to maintain plant growth effectively under water stress conditions was related to higher transpiration rates, levels of leaf conductance, and proline, N, and P contents. Differences in proline accumulation in leaves among the fungal symbioses suggested that the fungi were able to induce different degrees of osmotic adjustment. The detrimental effects of drought were not related to decreases in photosynthesis or water use efficiency. Neither of these parameters was related to P nutrition. The differences in P and K acquisition, transpiration, and stomatal conductance were related to the mycorrhizal efficiencies of the different fungi. Our observations revealed the propensities of different Glomus species to assert their protective effects during plant water stress. The greater effectiveness of G. deserticola in improving water deficit tolerance was associated with the lowest level of growth reduction (9%) under stress conditions. The growth of plants

  4. Combining physiological threshold knowledge to species distribution models is key to improving forecasts of the future niche for macroalgae.

    PubMed

    Martínez, Brezo; Arenas, Francisco; Trilla, Alba; Viejo, Rosa M; Carreño, Francisco

    2015-04-01

    Species distribution models (SDM) are a useful tool for predicting species range shifts in response to global warming. However, they do not explore the mechanisms underlying biological processes, making it difficult to predict shifts outside the environmental gradient where the model was trained. In this study, we combine correlative SDMs and knowledge on physiological limits to provide more robust predictions. The thermal thresholds obtained in growth and survival experiments were used as proxies of the fundamental niches of two foundational marine macrophytes. The geographic projections of these species' distributions obtained using these thresholds and existing SDMs were similar in areas where the species are either absent-rare or frequent and where their potential and realized niches match, reaching consensus predictions. The cold-temperate foundational seaweed Himanthalia elongata was predicted to become extinct at its southern limit in northern Spain in response to global warming, whereas the occupancy of southern-lusitanic Bifurcaria bifurcata was expected to increase. Combined approaches such as this one may also highlight geographic areas where models disagree potentially due to biotic factors. Physiological thresholds alone tended to over-predict species prevalence, as they cannot identify absences in climatic conditions within the species' range of physiological tolerance or at the optima. Although SDMs tended to have higher sensitivity than threshold models, they may include regressions that do not reflect causal mechanisms, constraining their predictive power. We present a simple example of how combining correlative and mechanistic knowledge provides a rapid way to gain insight into a species' niche resulting in consistent predictions and highlighting potential sources of uncertainty in forecasted responses to climate change. PMID:24917488

  5. Evaluating adaptation options of microcirculatory-tissue systems based on the physiological link of nutritive blood flow and redox ratio

    NASA Astrophysics Data System (ADS)

    Krupatkin, Alexander I.; Sidorov, Victor V.; Dremin, Victor V.; Dunaev, Andrey V.; Novikova, Irina N.; Zhu, Simian; Nabi, Ghulam; Litvinova, Karina S.; Baklanova, Anastasia P.; Bakshaliev, Ruslan M.; Ravcheev, Sergey A.

    2015-03-01

    Fluorescent spectroscopy (FS) is becoming more widely used in chemistry, biology, in various fields of medical technology and medicine in general. Many purulent wounds, burns and other destructive inflammatory processes are accompanied by changes in the fluorescent activity of the tissues, which occurs due to a misbalance in accumulation of natural fluorophores: FAD, NADH, lipofuscin, porphyrins, structural proteins, etc. The study of redox ratio (RR), characterizing the metabolic processes, is important in the assessment of the metabolic activity ofmicrocirculatory-tissue systems (MTS). However, one of the big problems of the FS method is still the correct interpretation of the data and the development of practical methods for its application in clinical medicine. To solve this problem and create new diagnostic criteria, we propose to evaluate the adaptive capacity of MTS using indicators of links between nutritive blood flow and redox ratio during a physiological rest and functional load (occlusion test). As is known, these parameters (RR and nutritive blood flow) characterize the metabolic activity of tissues.We have performedan experimental study of the relationship between the RR, defined by FS, and nutritive blood flow, defined by the methods of laser Doppler flowmetry. Preliminary results in the study of a complex approach to diagnosis of the state of biological tissue were obtained. A positive relationship between the nutritive blood flow in the microcirculatory channel and RR of skin tissue is observed.The speed of change of metabolism in the phase of occlusion and reperfusion and duration of phase of recovery may be the criteria for adaptive capabilities of MTS, which has practical significance for physiology and medicine.

  6. Euryhaline pufferfish NBCe1 differs from nonmarine species NBCe1 physiology

    PubMed Central

    Plata, Consuelo; Kurita, Yukihiro; Kato, Akira; Hirose, Shigehisa; Romero, Michael F.

    2012-01-01

    Marine fish drink seawater and eliminate excess salt by active salt transport across gill and gut epithelia. Euryhaline pufferfish (Takifugu obscurus, mefugu) forms a CaCO3 precipitate on the luminal gut surface after transitioning to seawater. NBCe1 (Slc4a4) at the basolateral membrane of intestinal epithelial cell plays a major role in transepithelial intestinal HCO3− secretion and is critical for mefugu acclimation to seawater. We assayed fugu-NBCe1 (fNBCe1) activity in the Xenopus oocyte expression system. Similar to NBCe1 found in other species, fNBCe1 is an electrogenic Na+/HCO3− cotransporter and sensitive to the stilbene inhibitor DIDS. However, our experiments revealed several unique and distinguishable fNBCe1 transport characteristics not found in mammalian or other teleost NBCe1-orthologs: electrogenic Li+/nHCO3− cotransport; HCO3− independent, DIDS-insensitive transport; and increased basal intracellular Na+ accumulation. fNBCe1 is a voltage-dependent Na+/nHCO3− cotransporter that rectifies, independently from the extracellular Na+ or HCO3− concentration, around −60 mV. Na+ removal (0Na+ prepulse) is necessary to produce the true HCO3−-elicited current. HCO3− addition results in huge outward currents with quick current decay. Kinetic analysis of HCO3− currents reveals that fNBCe1 has a much higher transport capacity (higher maximum current) and lower affinity (higher Km) than human kidney NBCe1 (hkNBCe1) does in the physiological range (membrane potential = −80 mV; [HCO3−] = 10 mM). In this state, fNBCe1 is in favor of operating as transepithelial HCO3− secretion, opposite of hkNBCe1, from blood to the luminal side. Thus, fugu-NBCe1 represents the first ortholog-based tool to study amino acid substitutions in NBCe1 and how those change ion and voltage dependence. PMID:22159080

  7. A functional–structural model of rice linking quantitative genetic information with morphological development and physiological processes

    PubMed Central

    Xu, Lifeng; Henke, Michael; Zhu, Jun; Kurth, Winfried; Buck-Sorlin, Gerhard

    2011-01-01

    Background and Aims Although quantitative trait loci (QTL) analysis of yield-related traits for rice has developed rapidly, crop models using genotype information have been proposed only relatively recently. As a first step towards a generic genotype–phenotype model, we present here a three-dimensional functional–structural plant model (FSPM) of rice, in which some model parameters are controlled by functions describing the effect of main-effect and epistatic QTLs. Methods The model simulates the growth and development of rice based on selected ecophysiological processes, such as photosynthesis (source process) and organ formation, growth and extension (sink processes). It was devised using GroIMP, an interactive modelling platform based on the Relational Growth Grammar formalism (RGG). RGG rules describe the course of organ initiation and extension resulting in final morphology. The link between the phenotype (as represented by the simulated rice plant) and the QTL genotype was implemented via a data interface between the rice FSPM and the QTLNetwork software, which computes predictions of QTLs from map data and measured trait data. Key Results Using plant height and grain yield, it is shown how QTL information for a given trait can be used in an FSPM, computing and visualizing the phenotypes of different lines of a mapping population. Furthermore, we demonstrate how modification of a particular trait feeds back on the entire plant phenotype via the physiological processes considered. Conclusions We linked a rice FSPM to a quantitative genetic model, thereby employing QTL information to refine model parameters and visualizing the dynamics of development of the entire phenotype as a result of ecophysiological processes, including the trait(s) for which genetic information is available. Possibilities for further extension of the model, for example for the purposes of ideotype breeding, are discussed. PMID:21247905

  8. Species and population variation to salinity stress in Panicum hemitomon, Spartina patens, and Spartina alterniflora: Morphological and physiological constraints

    USGS Publications Warehouse

    Hester, M.W.; Mendelssohn, I.A.; McKee, K.L.

    2001-01-01

    Panicum hemitomon, Spartina patens, and Spartina alterniflora are wide-spread dominant grasses of fresh, brackish, and salt marsh plant communities, respectively. Our previous research identified significant intraspecific variation in salt tolerance and morphology among populations within each species. In this study our objectives were to determine shorter-term physiological/biochemical responses to salinity stress and identify potential indicators of salt tolerance, with the ultimate goal of discerning similarities and differences in the mechanisms of salinity stress resistance. We subjected a subset of six populations within each species, ranging from high to low salt tolerance, to sublethal salinity levels (4, 20, and 30 ppt, respectively, for species) and monitored physiological and growth responses after 1 week (early harvest) and 5 weeks (late harvest). In all three species sublethal salinity levels generally resulted in significantly reduced net CO2 assimilation, leaf expansion, midday leaf xylem pressure, water use efficiency, and live and total biomass; and significantly increased leaf Na+/K+ ratio, leaf proline, leaf glycine betaine, leaf sucrose, root-to-shoot ratio, and dead:total aboveground biomass ratio. All three species displayed significant population (intraspecific) variation in net CO2 assimilation, leaf expansion, water use efficiency, midday leaf xylem pressure, leaf proline, leaf glycine betaine (except Panicum, where it could not be accurately determined), leaf Na+/K+ ratio, leaf sucrose, total plant biomass, dead:total aboveground biomass ratio, and root-to-shoot ratio. General indicators of salt tolerance (regardless of species) included high net CO2 assimilation rates and water use efficiencies, and low ratios of root-to-shoot and dead:total aboveground biomass. Factor analysis and a-priori linear contrasts revealed some unique differences between species in terms of the relative importance of morphology and physiology in explaining

  9. Physiological basis of seasonal trend in leaf photosynthesis of five evergreen broad-leaved species in a temperate deciduous forest.

    PubMed

    Miyazawa, Yoshiyuki; Kikuzawa, Kihachiro

    2006-02-01

    The physiological basis of photosynthesis during winter was investigated in saplings of five evergreen broad-leaved species (Camellia japonica L., Cleyera japonica Thunb., Photinia glabra (Thunb.) Maxim., Castanopsis cuspidata (Thunb.) Schottky and Quercus glauca Thunb.) co-occurring under deciduous canopy trees in a temperate forest. We focused on temperature dependence of photosynthetic rate and capacity as important physiological parameters that determine light-saturated rates of net photosynthesis at low temperatures during winter. Under controlled temperature conditions, maximum rates of ribulose bisphosphate carboxylation and electron transport (Vcmax) and Jmax, respectively) increased exponentially with increasing leaf temperature. The temperature dependence of photosynthetic rate did not differ among species. In the field, photosynthetic capacity, determined as Vcmax and Jmax at a common temperature of 25 degrees C (Vcmax(25) and Jmax(25)), increased until autumn and then decreased in species-specific patterns. Values of Vcmax(25) and Jmax(25) differed among species during winter. There was a positive correlation of Vcmax(25) with area-based nitrogen concentration among leaves during winter in Camellia and Photinia. Interspecific differences in Vcmax(25) were responsible for interspecific differences in light-saturated rates of net photosynthesis during winter. PMID:16356922

  10. Climate change, species distribution models, and physiological performance metrics: predicting when biogeographic models are likely to fail

    PubMed Central

    Woodin, Sarah A; Hilbish, Thomas J; Helmuth, Brian; Jones, Sierra J; Wethey, David S

    2013-01-01

    Modeling the biogeographic consequences of climate change requires confidence in model predictions under novel conditions. However, models often fail when extended to new locales, and such instances have been used as evidence of a change in physiological tolerance, that is, a fundamental niche shift. We explore an alternative explanation and propose a method for predicting the likelihood of failure based on physiological performance curves and environmental variance in the original and new environments. We define the transient event margin (TEM) as the gap between energetic performance failure, defined as CTmax, and the upper lethal limit, defined as LTmax. If TEM is large relative to environmental fluctuations, models will likely fail in new locales. If TEM is small relative to environmental fluctuations, models are likely to be robust for new locales, even when mechanism is unknown. Using temperature, we predict when biogeographic models are likely to fail and illustrate this with a case study. We suggest that failure is predictable from an understanding of how climate drives nonlethal physiological responses, but for many species such data have not been collected. Successful biogeographic forecasting thus depends on understanding when the mechanisms limiting distribution of a species will differ among geographic regions, or at different times, resulting in realized niche shifts. TEM allows prediction of the likelihood of such model failure. PMID:24223272

  11. Comparative physiology and relative swimming performance of three redhorse (Moxostoma spp.) species: associations with fishway passage success.

    PubMed

    Hatry, Charles; Thiem, Jason D; Binder, Thomas R; Hatin, Daniel; Dumont, Pierre; Stamplecoskie, Keith M; Molina, Juan M; Smokorowski, Karen E; Cooke, Steven J

    2014-01-01

    Our understanding of biological criteria to inform fish passage design is limited, partially due to the lack of understanding of biological motivators, cues, and constraints, as well as a lack of biological performance evaluations of structures once they are built. The Vianney-Legendre vertical slot fishway on the Richelieu River, Quebec, Canada, passes large numbers of migrating redhorse (Moxostoma spp.) upriver to spawning grounds each year. We evaluated the physiological capacity and relative swimming ability of three redhorse species (Moxostoma anisurum, Moxostoma carinatum, Moxostoma macrolepidotum; silver, river, and shorthead redhorse, respectively) to determine how these biotic factors relate to variation in fishway passage success and duration. Shorthead redhorse had higher maximum metabolic rates and were faster swimmers than silver and river redhorse at their species-specific peak migration temperatures. Blood lactate and glucose concentrations recovered more quickly for river redhorse than for silver and shorthead redhorse, and river redhorse placed second in terms of metabolic recovery and swim speed. Interestingly, fish sampled from the top of the fishway had nearly identical lactate, glucose, and pH values compared to control fish. Using passive integrated transponders in 2010 and 2012, we observed that passage success and duration were highly variable among redhorse species and were not consistent among years, suggesting that other factors such as water temperature and river flows may modulate passage success. Clearly, additional research is needed to understand how organismal performance, environmental conditions, and other factors (including abundance of conspecifics and other comigrants) interact with fishway features to dictate which fish will be successful and to inform research of future fishways. Our research suggests that there may be an opportunity for a rapid assessment approach where fish chased to exhaustion to determine maximal values

  12. Physiological responses to hypersalinity correspond to nursery ground usage in two inshore shark species (Mustelus antarcticus and Galeorhinus galeus).

    PubMed

    Tunnah, Louise; MacKellar, Sara R C; Barnett, David A; MacCormack, Tyson J; Stehfest, Kilian M; Morash, Andrea J; Semmens, Jayson M; Currie, Suzanne

    2016-07-01

    Shark nurseries are susceptible to environmental fluctuations in salinity because of their shallow, coastal nature; however, the physiological impacts on resident elasmobranchs are largely unknown. Gummy sharks (Mustelus antarcticus) and school sharks (Galeorhinus galeus) use the same Tasmanian estuary as a nursery ground; however, each species has distinct distribution patterns that are coincident with changes in local environmental conditions, such as increases in salinity. We hypothesized that these differences were directly related to differential physiological tolerances to high salinity. To test this hypothesis, we exposed wild, juvenile school and gummy sharks to an environmentally relevant hypersaline (120% SW) event for 48 h. Metabolic rate decreased 20-35% in both species, and gill Na(+)/K(+)-ATPase activity was maintained in gummy sharks but decreased 37% in school sharks. We measured plasma ions (Na(+), K(+), Cl(-)) and osmolytes [urea and trimethylamine oxide (TMAO)], and observed a 33% increase in plasma Na(+) in gummy sharks with hyperosmotic exposure, while school sharks displayed a typical ureosmotic increase in plasma urea (∼20%). With elevated salinity, gill TMAO concentration increased by 42% in school sharks and by 30% in gummy sharks. Indicators of cellular stress (heat shock proteins HSP70, 90 and 110, and ubiquitin) significantly increased in gill and white muscle in both a species- and a tissue-specific manner. Overall, gummy sharks exhibited greater osmotic perturbation and ionic dysregulation and a larger cellular stress response compared with school sharks. Our findings provide physiological correlates to the observed distribution and movement of these shark species in their critical nursery grounds. PMID:27207636

  13. Physiological Basis for Differential Sensitivities of Plant Species to Protoporphyrinogen Oxidase-Inhibiting Herbicides 1

    PubMed Central

    Sherman, Timothy D.; Becerril, José M.; Matsumoto, Hiroshi; Duke, Mary V.; Jacobs, Judy M.; Jacobs, Nicholas J.; Duke, Stephen O.

    1991-01-01

    With a leaf disc assay, 11 species were tested for effects of the herbicide acifluorfen on porphyrin accumulation in darkness and subsequent electrolyte leakage and photobleaching of chlorophyll after exposure to light. Protoporphyrin IX (Proto IX) was the only porphyrin that was substantially increased by the herbicide in any of the species. However, there was a wide range in the amount of Proto IX accumulation caused by 0.1 millimolar acifluorfen between species. Within species, there was a reduced effect of the herbicide in older tissues. Therefore, direct quantitative comparisons between species are difficult. Nevertheless, when data from different species and from tissues of different age within a species were plotted, there was a curvilinear relationship between the amount of Proto IX caused to accumulate during 20 hours of darkness and the amount of electrolyte leakage or chlorophyll photobleaching caused after 6 and 24 hours of light, respectively, following the dark period. Herbicidal damage plateaued at about 10 nanomoles of Proto IX per gram of fresh weight. Little difference was found between in vitro acifluorfen inhibition of protoporphyrinogen oxidase (Protox) of plastid preparations of mustard, cucumber, and morning glory, three species with large differences in their susceptibility at the tissue level. Mustard, a highly tolerant species, produced little Proto IX in response to the herbicide, despite having a highly susceptible Protox. Acifluorfen blocked carbon flow from δ-aminolevulinic acid to protochlorophyllide in mustard, indicating that it inhibits Protox in vivo. Increasing δ-aminolevulinic acid concentrations (33-333 micromolar) supplied to mustard with 0.1 millimolar acifluorfen increased Proto IX accumulation and herbicidal activity, demonstrating that mustard sensitivity to Proto IX was similar to other species. Differential susceptibility to acifluorfen of the species examined in this study appears to be due in large part to

  14. Avian vacuolar myelinopathy linked to exotic aquatic plants and a novel cyanobacterial species.

    PubMed

    Wilde, Susan B; Murphy, Thomas M; Hope, Charlotte P; Habrun, Sarah K; Kempton, Jason; Birrenkott, Anna; Wiley, Faith; Bowerman, William W; Lewitus, Alan J

    2005-06-01

    Invasions of exotic species have created environmental havoc through competition and displacement of native plants and animals. The introduction of hydrilla (Hydrilla verticillata) into the United States in the 1960s has been detrimental to navigation, power generation, water intake, and water quality (McCann et al., 1996). Our field surveys and feeding studies have now implicated exotic hydrilla and associated epiphytic cyanobacterial species as a link to avian vacuolar myelinopathy (AVM), an emerging avian disease affecting herbivorous waterbirds and their avian predators. AVM, first reported in 1994, has caused the death of at least 100 bald eagles (Haliaeetus leucocephalus) and thousands of American coots (Fulica americana) at 11 sites from Texas to North Carolina (Thomas et al., 1998; Rocke et al., 2002). Our working hypothesis is that the agent of this disease is an uncharacterized neurotoxin produced by a novel cyanobacterial epiphyte of the order Stigonematales. This undescribed species covers up to 95% of the surface area of leaves in reservoirs where bird deaths have occurred from the disease. In addition, this species is rare or not found on hydrilla collected at sites where AVM disease has not been diagnosed. Laboratory feeding trials and a sentinel bird study using naturally occurring blooms of cyanobacteria on hydrilla leaves and farm-raised mallard ducks (Anas platyrhynchos) induced the disease experimentally. Since 1994 AVM has been diagnosed in additional sites from Texas to North Carolina. Specific site characteristics that produce the disjunct distribution of AVM are unknown, but it is probable that the incidence of this disease will increase with the introduction of hydrilla and associated cyanobacterial species into additional ponds, lakes, and reservoirs. PMID:15892059

  15. Taxonomy and physiological characterisation of Scheffersomyces titanus sp. nov., a new D-xylose-fermenting yeast species from China

    PubMed Central

    Liu, Xiao-Jing; Cao, Wan-Nan; Ren, Yong-Cheng; Xu, Long-Long; Yi, Ze-Hao; Liu, Zheng; Hui, Feng-Li

    2016-01-01

    Three strains of a d-xylose-fermenting yeast species were isolated from the host beetle Dorcus titanus collected from two different localities in Henan Province, Central China. These strains formed two hat-shaped ascospores in conjugated and deliquescent asci. Multilocus phylogenetic analysis that included the nearly complete small subunit (SSU), the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit (LSU) rDNAs, as well as RNA polymerase II largest subunit (RPB1) gene demonstrated that these strains represent a novel yeast species belonging to the genus Scheffersomyces. The phylogenetic analysis based on the nucleotide sequences of the xylose reductase (XYL1) gene supported the view that the new strains could be grouped as a unique species. Although this new species is highly similar to Scheffersomyces stipitis-like yeasts in terms of nrDNA sequences and morphological and physiological characteristics, the species can be clearly differentiated from its close relatives on the basis of the sequences of XYL1 and RPB1. Therefore, a novel yeast species, Scheffersomyces titanus sp. nov., is proposed to accommodate these strains. The type strain is NYNU 14712T (CICC 33061T = CBS 13926T). PMID:27558134

  16. Taxonomy and physiological characterisation of Scheffersomyces titanus sp. nov., a new D-xylose-fermenting yeast species from China.

    PubMed

    Liu, Xiao-Jing; Cao, Wan-Nan; Ren, Yong-Cheng; Xu, Long-Long; Yi, Ze-Hao; Liu, Zheng; Hui, Feng-Li

    2016-01-01

    Three strains of a d-xylose-fermenting yeast species were isolated from the host beetle Dorcus titanus collected from two different localities in Henan Province, Central China. These strains formed two hat-shaped ascospores in conjugated and deliquescent asci. Multilocus phylogenetic analysis that included the nearly complete small subunit (SSU), the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit (LSU) rDNAs, as well as RNA polymerase II largest subunit (RPB1) gene demonstrated that these strains represent a novel yeast species belonging to the genus Scheffersomyces. The phylogenetic analysis based on the nucleotide sequences of the xylose reductase (XYL1) gene supported the view that the new strains could be grouped as a unique species. Although this new species is highly similar to Scheffersomyces stipitis-like yeasts in terms of nrDNA sequences and morphological and physiological characteristics, the species can be clearly differentiated from its close relatives on the basis of the sequences of XYL1 and RPB1. Therefore, a novel yeast species, Scheffersomyces titanus sp. nov., is proposed to accommodate these strains. The type strain is NYNU 14712(T) (CICC 33061(T) = CBS 13926(T)). PMID:27558134

  17. The low temperature induced physiological responses of Avena nuda L., a cold-tolerant plant species.

    PubMed

    Liu, Wenying; Yu, Kenming; He, Tengfei; Li, Feifei; Zhang, Dongxu; Liu, Jianxia

    2013-01-01

    The paperaim of the was to study the effect of low temperature stress on Avena nuda L. seedlings. Cold stress leads to many changes of physiological indices, such as membrane permeability, free proline content, malondialdehyde (MDA) content, and chlorophyll content. Cold stress also leads to changes of some protected enzymes such as peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). We have measured and compared these indices of seedling leaves under low temperature and normal temperature. The proline and MDA contents were increased compared with control; the chlorophyll content gradually decreased with the prolongation of low temperature stress. The activities of SOD, POD, and CAT were increased under low temperature. The study was designated to explore the physiological mechanism of cold tolerance in naked oats for the first time and also provided theoretical basis for cultivation and antibiotic breeding in Avena nuda L. PMID:23843738

  18. Biochemical and physiological effects of metazoan endoparasites on their host species.

    PubMed

    Thompson, S N

    1983-01-01

    1. The integrative nature of the parasite-host association was discussed, specifically with regard to the metabolic effects of parasitization as well as the physiological manifestation of infection in relation to the host's nutritional physiology. Endocrine interactions were also considered. 2. Relationships involving parasitic insects, including members of the orders Diptera, Hymenoptera and Strepsiptera, parasitic helminths, including members of the phyla Acanthocephala and Nematoda and the classes Cestoidea and Trematoda of the Platyhelminthes, as well as parasitic crustaceans in association with their invertebrate and/or vertebrate, intermediate, paratenic as well as definitive hosts were considered. 3. A broad conceptual or "topic" approach to understanding symbiotic relationships was emphasized. De-emphasis of descriptive categorization and the use of benefit/harm as criteria characterizing parasitic relationships was suggested. 4. The hypothetical concept of host regulation was briefly examined and the use of anthropometric descriptors such as "beneficial" and "harmonious" in parasitology discussed. PMID:6339157

  19. No evidence for melatonin-linked immunoenhancement over the annual cycle of an avian species.

    PubMed

    Buehler, Deborah M; Koolhaas, Anita; Van't Hof, Thomas J; Schwabl, Ingrid; Dekinga, Anne; Piersma, Theunis; Tieleman, B Irene

    2009-05-01

    The winter immunoenhancement hypothesis associates long nights and increased exposure to melatonin with enhanced immune function in winter when resource availability is low and the chances of becoming ill are high. Thus, increased exposure to melatonin in the winter could be adaptive for species facing difficult winter conditions. This idea has found some support in studies of resident mammals. In birds, the link between day length and melatonin over the annual cycle is weaker, and contributions of melatonin to seasonal timing are unclear. Furthermore, many species, especially migrants, do not experience the most difficult conditions of their annual cycle in winter. In this study, we tested whether the winter immunoenhancement hypothesis holds in an avian species, the red knot Calidris canutus. We found that melatonin duration and amplitude varied significantly over the annual cycle with the highest values occurring in winter. However, peaks did not correspond to the winter solstice or with annual variation in immune function. Our findings do not support the winter immunoenhancement hypothesis in knots and question whether the idea that immune function should be bolstered in winter can be generalized to systems where winter is not the most difficult time of the year. PMID:19234709

  20. Flooding effects on plant physiology and VOC emissions from Amazonian tree species from two different flooding environments: Varzea and Igapo

    NASA Astrophysics Data System (ADS)

    Bracho Nunez, A.; Knothe, N.; Liberato, M. A. R.; Schebeske, G.; Ciccioli, P.; Piedade, M. T. F.; Kesselmeier, J.

    2009-04-01

    A land area of 300.000 km² in the Amazon basin is subjected to a continuous flooding pulse, being flooded for 210 days a-1 on an average (Junk et al. 1993). To survive the flooding period vegetation has developed several morphological, anatomical and physiological strategies to mitigate the produced stress due to root anoxia. One of the strategies is fermentation of sucrose in the roots to comply with the energy demand under anoxia. The resulting toxic metabolite ethanol is transported through the transpiration stream to the leaves and can be directly emitted into the atmosphere or converted to acetaldehyde and/or acetate, still volatile enough to be partly released. We investigated short-term and long-term flooding effects on physiology and VOC emission by plant species from várzea and igapó and observed ethanol and acetaldehyde emissions from the várzea species Vatairea guianensis after one day of flooding, which decreased considerably within the next three days. The same species from igapó showed no acetaldehyde emission and much lower emission rates of ethanol, than the várzea species. In contrast Hevea spruceana from both várzea and igapó showed no ethanol or acetaldehyde emissions. After long term flooding (2 months) we did not find any emissions of acetaldehyde or ethanol from all plant species investigated. However, isoprene and monoterpene emissions were clearly affected, showing a significant decrease. Carbon dioxide assimilation was not affected by short term flooding, but declined after two months root anoxia in the case of Hevea spruceana.

  1. Linking Reproduction and Survival Can Improve Model Estimates of Vital Rates Derived from Limited Time-Series Counts of Pinnipeds and Other Species

    PubMed Central

    Battaile, Brian C.; Trites, Andrew W.

    2013-01-01

    We propose a method to model the physiological link between somatic survival and reproductive output that reduces the number of parameters that need to be estimated by models designed to determine combinations of birth and death rates that produce historic counts of animal populations. We applied our Reproduction and Somatic Survival Linked (RSSL) method to the population counts of three species of North Pacific pinnipeds (harbor seals, Phoca vitulina richardii (Gray, 1864); northern fur seals, Callorhinus ursinus (L., 1758); and Steller sea lions, Eumetopias jubatus (Schreber, 1776))—and found our model outperformed traditional models when fitting vital rates to common types of limited datasets, such as those from counts of pups and adults. However, our model did not perform as well when these basic counts of animals were augmented with additional observations of ratios of juveniles to total non-pups. In this case, the failure of the ratios to improve model performance may indicate that the relationship between survival and reproduction is redefined or disassociated as populations change over time or that the ratio of juveniles to total non-pups is not a meaningful index of vital rates. Overall, our RSSL models show advantages to linking survival and reproduction within models to estimate the vital rates of pinnipeds and other species that have limited time-series of counts. PMID:24324541

  2. Shared Physiological Traits of Exophiala Species in Cold-Blooded Vertebrates, as Opportunistic Black Yeasts.

    PubMed

    do Nascimento, Mariana Machado Fidelis; de Hoog, G Sybren; Gomes, Renata Rodrigues; Furuie, Jason Lee; Gelinski, Jane Mary Lafayette; Najafzadeh, Mohammad Javad; Boeger, Walter Antonio Pereira; Vicente, Vania Aparecida

    2016-06-01

    Several species of the genus Exophiala are found as opportunistic pathogens on humans, while others cause infections in cold-blooded waterborne vertebrates. Opportunism of these fungi thus is likely to be multifactorial. Ecological traits [thermotolerance and pH tolerance, laccase activity, assimilation of mineral oil, and decolorization of Remazol Brilliant Blue R (RBBR)] were studied in a set of 40 strains of mesophilic Exophiala species focused on the salmonis-clade mainly containing waterborne species. Thermophilic species and waterborne species outside the salmonis-clade were included for comparison. Strains were able to tolerate a wide range of pHs, although optimal growth was observed between pH 4.0 and 5.5. All strains tested were laccase positive. Strains were able to grow in the presence of the compounds (mineral oil and RBBR) with some differences in assimilation patterns between strains tested and also were capable of degrading the main chromophore of RBBR. The study revealed that distantly related mesophilic species behave similarly, and no particular trend in evolutionary adaptation was observed. PMID:27028446

  3. Host-plant specialization in the Drosophila melanogaster species complex: a physiological, behavioral, and genetical analysis.

    PubMed

    R'Kha, S; Capy, P; David, J R

    1991-03-01

    Drosophila sechellia, endemic to the Seychelles, breeds in a single resource, Morinda citrifolia, whereas its close sympatric relative, Drosophila simulans, is a cosmopolitan generalist breeding in a great variety of resources. The effects of morinda on various fitness traits of these two species, their F1 hybrids, and reciprocal backcrosses were analyzed. Morinda fruit is highly toxic to Drosophila species, except D. sechellia. The toxicity is expressed in adults, embryos, and larvae. In embryos, early mortality is a maternally inherited trait, depending only on mother's genotype. The tolerance of D. sechellia to morinda is fully dominant in F1 hybrids. Egg production is stimulated by morinda in D. sechellia but inhibited in D. simulans; in hybrids, the inhibition observed in D. simulans is dominant. Morinda is an oviposition attractant for D. sechellia but a repellent for D. simulans; F1 hybrids and backcross individuals exhibit intermediate, approximately additive, behavior. In the field, adult flies of the two species exhibit opposite behavior in that D. sechellia is attracted to morinda and D. simulans is attracted to banana; hybrids have an intermediate behavior. These differences between the species explain why they do not hybridize in nature although living in sympatry. The various traits have different genetic bases: three or four different genes, or groups of genes, differentiate the ecological niches of the two species. PMID:1900368

  4. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings

    PubMed Central

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  5. Arbuscular Mycorrhizal Fungus Species Dependency Governs Better Plant Physiological Characteristics and Leaf Quality of Mulberry (Morus alba L.) Seedlings.

    PubMed

    Shi, Song-Mei; Chen, Ke; Gao, Yuan; Liu, Bei; Yang, Xiao-Hong; Huang, Xian-Zhi; Liu, Gui-Xi; Zhu, Li-Quan; He, Xin-Hua

    2016-01-01

    Understanding the synergic interactions between arbuscular mycorrhizal fungi (AMF) and its host mulberry (Morus alba L.), an important perennial multipurpose plant, has theoretical and practical significance in mulberry plantation, silkworm cultivation, and relevant textile industry. In a greenhouse study, we compared functional distinctions of three genetically different AMF species (Acaulospora scrobiculata, Funneliformis mosseae, and Rhizophagus intraradices) on physiological and growth characteristics as well as leaf quality of 6-month-old mulberry seedlings. Results showed that mulberry was AMF-species dependent, and AMF colonization significantly increased shoot height and taproot length, stem base and taproot diameter, leaf and fibrous root numbers, and shoot and root biomass production. Meanwhile, leaf chlorophyll a or b and carotenoid concentrations, net photosynthetic rate, transpiration rate and stomatal conductance were generally significantly greater, while intercellular CO2 concentration was significantly lower in AMF-inoculated seedlings than in non-AMF-inoculated counterparts. These trends were also generally true for leaf moisture, total nitrogen, all essential amino acids, histidine, proline, soluble protein, sugar, and fatty acid as they were significantly increased under mycorrhization. Among these three tested AMFs, significantly greater effects of AMF on above-mentioned mulberry physiological and growth characteristics ranked as F. mosseae > A. scrobiculata > R. intraradices, whilst on mulberry leaf quality (e.g., nutraceutical values) for better silkworm growth as F. mosseae ≈A. scrobiculata > R. intraradices. In conclusion, our results showed that greater mulberry biomass production, and nutritional quality varied with AMF species or was AMF-species dependent. Such improvements were mainly attributed to AMF-induced positive alterations of mulberry leaf photosynthetic pigments, net photosynthetic rate, transpiration rate, and N

  6. Identification of molecular and physiological responses to chronic environmental challenge in an invasive species: the Pacific oyster, Crassostrea gigas

    PubMed Central

    Clark, Melody S; Thorne, Michael A S; Amaral, Ana; Vieira, Florbela; Batista, Frederico M; Reis, João; Power, Deborah M

    2013-01-01

    Understanding the environmental responses of an invasive species is critical in predicting how ecosystem composition may be transformed in the future, especially under climate change. In this study, Crassostrea gigas, a species well adapted to the highly variable intertidal environment, was exposed to the chronic environmental challenges of temperature (19 and 24°C) and pH (ambient seawater and a reduction of 0.4 pH units) in an extended 3-month laboratory-based study. Physiological parameters were measured (condition index, shell growth, respiration, excretion rates, O:N ratios, and ability to repair shell damage) alongside molecular analyses. Temperature was by far the most important stressor, as demonstrated by reduced condition indexes and shell growth at 24°C, with relatively little effect detected for pH. Transcriptional profiling using candidate genes and SOLiD sequencing of mantle tissue revealed that classical “stress” genes, previously reported to be upregulated under acute temperature challenges, were not significantly expressed in any of the treatments, emphasizing the different response between acute and longer term chronic stress. The transcriptional profiling also elaborated on the cellular responses underpinning the physiological results, including the identification of the PI3K/AKT/mTOR pathway as a potentially novel marker for chronic environmental challenge. This study represents a first attempt to understand the energetic consequences of cumulative thermal stress on the intertidal C. gigas which could significantly impact on coastal ecosystem biodiversity and function in the future. PMID:24223268

  7. Physiological and pathophysiological reactive oxygen species as probed by EPR spectroscopy: the underutilized research window on muscle ageing.

    PubMed

    A Abdel-Rahman, Engy; Mahmoud, Ali M; Khalifa, Abdulrahman M; Ali, Sameh S

    2016-08-15

    Reactive oxygen and nitrogen species (ROS and RNS) play crucial roles in triggering, mediating and regulating physiological and pathophysiological signal transduction pathways within the cell. Within the cell, ROS efflux is firmly controlled both spatially and temporally, making the study of ROS dynamics a challenging task. Different approaches have been developed for ROS assessment; however, many of these assays are not capable of direct identification or determination of subcellular localization of different ROS. Here we highlight electron paramagnetic resonance (EPR) spectroscopy as a powerful technique that is uniquely capable of addressing questions on ROS dynamics in different biological specimens and cellular compartments. Due to their critical importance in muscle functions and dysfunction, we discuss in some detail spin trapping of various ROS and focus on EPR detection of nitric oxide before highlighting how EPR can be utilized to probe biophysical characteristics of the environment surrounding a given stable radical. Despite the demonstrated ability of EPR spectroscopy to provide unique information on the identity, quantity, dynamics and environment of radical species, its applications in the field of muscle physiology, fatiguing and ageing are disproportionately infrequent. While reviewing the limited examples of successful EPR applications in muscle biology we conclude that the field would greatly benefit from more studies exploring ROS sources and kinetics by spin trapping, protein dynamics by site-directed spin labelling, and membrane dynamics and global redox changes by spin probing EPR approaches. PMID:26801204

  8. Linking Radial Species Segregation and Bubbling Patterns in Gas-Fluidized Beds.

    NASA Astrophysics Data System (ADS)

    Joseph, Gustavo; Hrenya, Christine; Kozlowski, Joe

    2007-11-01

    Binary mixtures of gas-fluidized Geldart Group B particles with size and/or density differences were experimentally investigated at gas velocities up to 3 times the complete fluidization velocities (ufc) of the mixtures. Steady state operation of the bed was ensured prior to data collection. Local bubbling information (mean bubble size, bubble rise velocity, and bubbling frequency) was obtained throughout the bed by means of a backscattered-light optical probe. Segregation data were obtained via bed ``freezing'' and subsequent sieving of layers. Monodisperse runs were also performed as benchmarks for the binary-mixture runs. Perceptible radial variations in species composition were encountered, with the less massive particles tending toward the bed center in most cases. For systems where the species differed in both size and density, the bottom layer presents a reversal of radial segregation pattern at gas velocities below 2ufc. At velocities below 2ufc, bubbling is seen predominantly at the bed periphery, with qualitative differences between monodisperse and mixed systems above 2ufc. A detailed analysis of the bubbling patterns at the various compositions and gas velocities is presented, and links to the observed segregation behavior are made.

  9. Determination of binary diffusion coefficients of various gas species used in respiratory physiology.

    PubMed

    Worth, H; Nüsse, W; Piiper, J

    1978-01-01

    In order to provide data required for quantitative analysis of gas diffusion in lung airways, diffusion of He, CO, O2, CO2 and SF6 in various gases used in respiratory physiology was studied in vitro at 37 degrees C and 25 degrees C. The gases were allowed to mix by diffusion in a closed cylindrical tube (length 2 m, internal diameter 1 cm), one half of which was initially filled with 1% test gas in a second gas and the other half of which was filled with the second gas only. Kinetics of diffusional equilibration was determined by withdrawal of spot samples analyzed by gas chromatography. The binary (mutual) diffusion coefficients (D) computed there from were in most cases in good agreement with values calculated on the basis of the Chapman-Enskog theory. PMID:625611

  10. Linking the lytic and lysogenic bacteriophage cycles to environmental conditions, host physiology and their variability in coastal lagoons.

    PubMed

    Maurice, C F; Bouvier, C; de Wit, R; Bouvier, T

    2013-09-01

    Changes in environmental conditions and prokaryote physiology can strongly affect the dynamics of both the lysogenic and lytic bacteriophage replication cycles in aquatic systems. However, it remains unclear whether it is the nature, amplitude or frequency of these changes that alter the phage replication cycles. We performed an annual survey of three Mediterranean lagoons with contrasting levels of chlorophyll a concentration and salinity to explore how these cues and their variability influence either replication cycle. The lytic cycle was always detected and showed seasonal patterns, whereas the lysogenic cycle was often undetected and highly variable. The lytic cycle was influenced by environmental and prokaryotic physiological cues, increasing with concentrations of dissolved organic carbon, chlorophyll a, and the proportion of respiring cells, and decreasing with the proportion of damaged cells. In contrast, lysogeny was not explained by the magnitude of any environmental or physiological parameter, but increased with the amplitude of change in prokaryote physiology. Our study suggests that both cycles are regulated by distinct factors: the lytic cycle is dependent on environmental parameters and host physiology, while lysogeny is dependent on the variability of prokaryote physiology. This could lead to the contrasting patterns observed between both cycles in aquatic systems. PMID:23581698

  11. Differential physiological responses of two Salvinia species to hexavalent chromium at a glance.

    PubMed

    Prado, Carolina; Chocobar Ponce, Silvana; Pagano, Eduardo; Prado, Fernando E; Rosa, Mariana

    2016-06-01

    In plants of Salvinia rotundifolia and Salvinia minima the effect of two Cr(VI) concentrations (5 and 20mgL(-1)) applied for 7days was assessed by measuring changes in biomass, photosynthetic pigments, Cr accumulation, malondialdehyde (MDA), membrane stability index (MSI), thiols (TT, NPT and PBT), and phenolics (SP and IP). Biomass in S. minima was decreased at highest Cr(VI) concentration, but there were no changes in S. rotundifolia. Metal accumulation was different in both species. S. minima accumulates more metal in fronds, but S. rotundifolia accumulates more metal in lacinias. Results also showed that S. minima translocates more Cr to fronds than S. rotundifolia, but at the whole plant level higher accumulation occurred in this last. Tolerance index (Ti) was higher in S. rotundifolia. Chl b and carotenoids were decreased only upon exposure to high Cr(VI) concentration in both species. Cr(VI) treatment did not enhance MDA accumulation. Cr exposure had no impact on MSI values when comparing with Cr-untreated values. Thiols in fronds and lacinias showed different distribution patterns between species. IP and NPT were higher in S. rotundifolia lacinias that accumulate more Cr than S. minima lacinias. Whilst SP and NPT were higher in S. minima fronds compared with S. rotundifolia ones. This may indicate that these species can cope with Cr(VI) toxicity, either through metal complexation and/or metal reduction or by the scavenging of ROS derived from Cr-induced oxidative stress. Based on Cr accumulation and biomass production, S. rotundifolia seems more suitable to remove Cr(VI) from polluted waters. PMID:27061358

  12. Ectotherms in Variable Thermal Landscapes: A Physiological Evaluation of the Invasive Potential of Fruit Flies Species.

    PubMed

    Boher, Francisca; Trefault, Nicole; Estay, Sergio A; Bozinovic, Francisco

    2016-01-01

    Climate change and biological invasions pose one of the greatest threats to biodiversity. Most analyses of the potential biological impacts have focused on changes in mean temperature, but changes in thermal variance may also impact native and invasive organisms, although differentially. We assessed the combined effects of the mean and the variance of temperature on the expression of heat shock protein (hsp90) in adults of the invasive fruit fly Drosophila melanogaster and the native Drosophila gaucha in Mediterranean habitats of central Chile. We observed that, under these experimental conditions, hsp90 mRNA expression was higher in the invasive species but absent in the native one. Apparently, the biogeographic origin and niche conservatisms are playing a role in the heat shock response of these species under different putative scenarios of climate change. We suggest that in order to develop more realistic predictions about the biological impact of climate change and biological invasions, one must consider the interactions between the mean and variance of climatic variables, as well as the evolutionary original conditions of the native and invasive species. PMID:27486407

  13. Ectotherms in Variable Thermal Landscapes: A Physiological Evaluation of the Invasive Potential of Fruit Flies Species

    PubMed Central

    Boher, Francisca; Trefault, Nicole; Estay, Sergio A.; Bozinovic, Francisco

    2016-01-01

    Climate change and biological invasions pose one of the greatest threats to biodiversity. Most analyses of the potential biological impacts have focused on changes in mean temperature, but changes in thermal variance may also impact native and invasive organisms, although differentially. We assessed the combined effects of the mean and the variance of temperature on the expression of heat shock protein (hsp90) in adults of the invasive fruit fly Drosophila melanogaster and the native Drosophila gaucha in Mediterranean habitats of central Chile. We observed that, under these experimental conditions, hsp90 mRNA expression was higher in the invasive species but absent in the native one. Apparently, the biogeographic origin and niche conservatisms are playing a role in the heat shock response of these species under different putative scenarios of climate change. We suggest that in order to develop more realistic predictions about the biological impact of climate change and biological invasions, one must consider the interactions between the mean and variance of climatic variables, as well as the evolutionary original conditions of the native and invasive species. PMID:27486407

  14. Physiological Potential for Survival of Propagules of Crassulacean Acid Metabolism Species 1

    PubMed Central

    Holthe, Peter A.; Szarek, Stan R.

    1985-01-01

    Terminal stem joints from three opuntias were detached and maintained for 160 days under natural climatic conditions in the winter and summer. Neither Crassulacean acid metabolism (CAM) nor CAM-idling, as evidenced by a diurnal malate flux, was maintained throughout the two periods; ceasing earlier in the summer period. A 13 to 20% fresh weight loss occurred over the winter period, as opposed to a 30 to 40% loss over the summer period, although tissue water potentials remained above −1.5 megapascals. Chlorophyll and protein contents remained essentially constant in the winter but decreased in the summer. Starch content decreased slightly over the winter but more significantly over the summer. Mucilage content increased slightly in winter and declined slightly in summer. The initiation of rooting was found to be inversely related to spine density and dependent upon orientation and season. Comparison of these data suggest rooting coincided with the cessation of CAM-idling in both climatic periods and was uncoupled from the occurrence of precipitation. The physiological limit for survival of these propagules after detachment was lower than anticipated being of only a few months' duration. PMID:16664374

  15. Physiological effects of sublethal levels of acid water on three species of fishes

    SciTech Connect

    Pegg, W.J.

    1984-01-01

    Static toxicity tests revealed the need to assess the effect of acid mine water using some procedure that would gradually increase the concentration of acidity over a period of time. A relatively long-term (2-5 days) experiment involving the devlopment of a sublethal acid treatment gradient was chosen as potentially being the most representative of natural environments which are periodically subjected to changing inputs from coal mine drainage. Since respiratory change is an indication of physiological stress, the measurement of oxygen consumption rate was chosen as the major variable representing the effect of acid waters on fishes. Bluegill sunfish Lepomes macrochirus Rafinesque, pumpkinseed sunfish, Lepomis gibbosus (Linnaeus), and brown bullhead, Ictalurus nebulosus (LeSueur) were collected from the Monongahela River and backwater areas in the region of Morgantown, West Virginia. The sublethal acid water treatments decreased the oxygen consumption rates for brown bullhead and bluegill sunfish, while increasing the oxygen consumption rate for pumpkinseed sunfish. Further, the rhythms of the oxygen consumption rates were generally modified in both frequency and amplitude as a result of exposure to acid water. Acid water treatments also caused negative phase shifts in oxygen consumption rate for brown bullhead sand bluegill sunfish, while positive phase shifts occurred for pumpkinseed sunfish.

  16. Genomic architecture of MHC-linked odorant receptor gene repertoires among 16 vertebrate species.

    PubMed

    Santos, Pablo Sandro Carvalho; Kellermann, Thomas; Uchanska-Ziegler, Barbara; Ziegler, Andreas

    2010-09-01

    The recent sequencing and assembly of the genomes of different organisms have shown that almost all vertebrates studied in detail so far have one or more clusters of genes encoding odorant receptors (OR) in close physical linkage to the major histocompatibility complex (MHC). It has been postulated that MHC-linked OR genes could be involved in MHC-influenced mate choice, comprising both pre- as well as post-copulatory mechanisms. We have therefore carried out a systematic comparison of protein sequences of these receptors from the genomes of man, chimpanzee, gorilla, orangutan, rhesus macaque, mouse, rat, dog, cat, cow, pig, horse, elephant, opossum, frog and zebra fish (amounting to a total of 559 protein sequences) in order to identify OR families exhibiting evolutionarily conserved MHC linkage. In addition, we compared the genomic structure of this region within these 16 species, accounting for presence or absence of OR gene families, gene order, transcriptional orientation and linkage to the MHC or framework genes. The results are presented in the form of gene maps and phylogenetic analyses that reveal largely concordant repertoires of gene families, at least among tetrapods, although each of the eight taxa studied (primates, rodents, ungulates, carnivores, proboscids, marsupials, amphibians and teleosts) exhibits a typical architecture of MHC (or MHC framework loci)-linked OR genes. Furthermore, the comparison of the genomic organization of this region has implications for phylogenetic relationships between closely related taxa, especially in disputed cases such as the evolutionary history of even- and odd-toed ungulates and carnivores. Finally, the largely conserved linkage between distinct OR genes and the MHC supports the concept that particular alleles within a given haplotype function in a concerted fashion during self-/non-self-discrimination processes in reproduction. PMID:20680261

  17. [Effects of elevated CO2 concentration on physiological characters of three dwarf ornamental bamboo species].

    PubMed

    Zhuang, Ming-Hao; Chen, Shuang-Lin; Li, Ying-Chun; Guo, Zi-Wu; Yang, Qing-Ping

    2013-09-01

    By using open-top chambers (OTCs) to simulate the scenes of elevated CO2 concentrations [500 micromol x mol(-1) (T1) and 700 micromol x mol(-1) (T2)], and taking ambient atmospheric CO2 concentration as the control (CK), this paper studied the effects of elevated CO2 concentration on the lipid peroxidation and anti-oxidation enzyme system in Indocalamus decorus, Pleioblastus kongosanensis, and Sasa glabra leaves. After 103 days treatment, the O2(-)* and MDA contents, relative electron conduction, and soluble sugar content in the three dwarf ornamental bamboo species leaves in T1 had no obvious change, but the activities of anti-oxidation enzymes (SOD, POD, CAT, and APX) changed to a certain extent. In T2, the MDA content and relative electron conduction had no obvious change, but the O2(-)* and soluble sugar contents and the anti-oxidation enzymes activities changed obviously. The adaptation capacity of the three bamboo species to elevated CO2 concentration was in the order of I. decorus > P. kongosanensis > S. glabra. PMID:24417095

  18. Linking xylem water storage with anatomical parameters in five temperate tree species.

    PubMed

    Jupa, Radek; Plavcová, Lenka; Gloser, Vít; Jansen, Steven

    2016-06-01

    The release of water from storage compartments to the transpiration stream is an important functional mechanism that provides the buffering of sudden fluctuations in water potential. The ability of tissues to release water per change in water potential, referred to as hydraulic capacitance, is assumed to be associated with the anatomy of storage tissues. However, information about how specific anatomical parameters determine capacitance is limited. In this study, we measured sapwood capacitance (C) in terminal branches and roots of five temperate tree species (Fagus sylvatica L., Picea abies L., Quercus robur L., Robinia pseudoacacia L., Tilia cordata Mill.). Capacitance was calculated separately for water released mainly from capillary (CI; open vessels, tracheids, fibres, intercellular spaces and cracks) and elastic storage compartments (CII; living parenchyma cells), corresponding to two distinct phases of the moisture release curve. We found that C was generally higher in roots than branches, with CI being 3-11 times higher than CII Sapwood density and the ratio of dead to living xylem cells were most closely correlated with C In addition, the magnitude of CI was strongly correlated with fibre/tracheid lumen area, whereas CII was highly dependent on the thickness of axial parenchyma cell walls. Our results indicate that water released from capillary compartments predominates over water released from elastic storage in both branches and roots, suggesting the limited importance of parenchyma cells for water storage in juvenile xylem of temperate tree species. Contrary to intact organs, water released from open conduits in our small wood samples significantly increased CI at relatively high water potentials. Linking anatomical parameters with the hydraulic capacitance of a tissue contributes to a better understanding of water release mechanisms and their implications for plant hydraulics. PMID:27083523

  19. Exogenous sodium sulfide improves morphological and physiological responses of a hybrid Populus species to nitrogen dioxide.

    PubMed

    Hu, Yanbo; Bellaloui, Nacer; Sun, Guangyu; Tigabu, Mulualem; Wang, Jinghong

    2014-06-15

    Gaseous nitrogen dioxide (NO2) can disturb normal plant growth and trigger complex physiological responses. NO2-induced responses are influenced by biotic or abiotic factors. In this study, we investigated the effects of exogenous sodium sulfide (Na2S, 5mmolL(-1)) on epidermis and stomata related physico-chemical responses of hybrid poplar cuttings (Pouplus alba×P. berolinensis) to gaseous NO2 (4μl1(-1)) for three time periods (0, 14 and 48h). We also investigated hydrogen sulfide (H2S), nitrate-nitrogen and nitrate reductase activity (NR) in control and Na2S treated plants. Our results showed that NO2 exposure for 48h led to the decline of NR, maximal PSII quantum yield (Fv/Fm), net photosynthetic rate (Pn), and dark respiration rate (Rd). The maximum rate for the post-illumination carbon dioxide burst (PIB) occurred in 48-h exposed leaves 13-15s after darkening. Moreover, NO2 exposure resulted in a significant increase in nitrogen percentage (from 0 to 33%) and a decrease in the macro and micro-elements of leaf surface. Spraying Na2S aqueous solution on the leaf surfaces significantly increased the thicknesses of palisade/spongy tissue and H2S content. Na2S pretreatment alleviated NO2-caused toxic effects as indicated by increased NR and higher values of Pn, Fv/Fm, and actual photochemical efficiency in light (ФPSII) compared with the control. Na2S pretreatment had no significant impacts on PIB-based photorespiration or elements composition of a leaf surface. PMID:24635903

  20. The role of relaxin in mare reproductive physiology: A comparative review with other species.

    PubMed

    Klein, Claudia

    2016-07-01

    Relaxin is a peptide hormone best known for its action during the latter half of pregnancy, in particular for its softening effect on pelvic ligaments that aids in preparation of the birth canal for the impending delivery of the fetus. The source of relaxin during early pregnancy varies across species, with the CL being the main source in a number of species. The main source of relaxin during late equine pregnancy is the placenta. In mares with impaired placental function, circulating relaxin levels decline before abortion. During early pregnancy, relaxin promotes endometrial angiogenesis through upregulating endometrial expression of vascular endothelial growth factor. The horse is unique in that the equine conceptus expresses relaxin messenger RNA as early as 8 days after ovulation, with levels increasing as conceptus development proceeds. Although secretion of functional relaxin has not been verified, it is likely, given that the embryo also expresses transcripts coding for enzymes processing the prohormone to yield the mature hormone. Furin, an enzyme which belongs to the subtilisin-like proprotein convertase family known to process preprorelaxin, appears to be the foremost convertase expressed by equine conceptuses. Conceptus-derived relaxin could drive endometrial angiogenesis and also act in an autocrine fashion to promote the embryo's own development. Relaxin is also expressed by ovarian structures during the nonpregnant estrous cycle. In the mare, follicular expression of relaxin is comparable among follicles of varying size and has been localized to granulosa and theca cells. In women and pigs, relaxin appears to promote follicular development. In the rat, multiple lines of evidence indicate that relaxin is involved in the ovulatory process. In the mare, relaxin might play a similar role in the ovulatory process, as in equine ovarian stromal cells relaxin promotes the secretion of gelatinases and tissue inhibitors of metalloproteinases; local proteolysis

  1. Interactions of drought and shade effects on seedlings of four Quercus species: physiological and structural leaf responses.

    PubMed

    Quero, José Luis; Villar, Rafael; Marañón, Teodoro; Zamora, Regino

    2006-01-01

    Here, we investigated the physiological and structural leaf responses of seedlings of two evergreen and two deciduous Quercus species, grown in a glasshouse and subjected to contrasted conditions of light (low, medium and high irradiance) and water (continuous watering vs 2-months drought). The impact of drought on photosynthetic rate was strongest in high irradiance, while the impact of shade on photosynthetic rate was strongest with high water supply, contradicting the hypothesis of allocation trade-off. Multivariate causal models were evaluated using d-sep method. The model that best fitted the dataset proposed that the variation in specific leaf area affects photosynthetic rate and leaf nitrogen concentration, and this trait determines stomatal conductance, which also affects photosynthetic rate. Shade conditions seemed to ameliorate, or at least not aggravate, the drought impact on oak seedlings, therefore, the drought response on leaf performance depended on the light environment. PMID:16684241

  2. Atomic structure of a rhinovirus C, a virus species linked to severe childhood asthma.

    PubMed

    Liu, Yue; Hill, Marchel G; Klose, Thomas; Chen, Zhenguo; Watters, Kelly; Bochkov, Yury A; Jiang, Wen; Palmenberg, Ann C; Rossmann, Michael G

    2016-08-01

    Isolates of rhinovirus C (RV-C), a recently identified Enterovirus (EV) species, are the causative agents of severe respiratory infections among children and are linked to childhood asthma exacerbations. The RV-C have been refractory to structure determination because they are difficult to propagate in vitro. Here, we report the cryo-EM atomic structures of the full virion and native empty particle (NEP) of RV-C15a. The virus has 60 "fingers" on the virus outer surface that probably function as dominant immunogens. Because the NEPs also display these fingers, they may have utility as vaccine candidates. A sequence-conserved surface depression adjacent to each finger forms a likely binding site for the sialic acid on its receptor. The RV-C, unlike other EVs, are resistant to capsid-binding antiviral compounds because the hydrophobic pocket in VP1 is filled with multiple bulky residues. These results define potential molecular determinants for designing antiviral therapeutics and vaccines. PMID:27511920

  3. Children's Patterns of Emotional Reactivity to Conflict as Explanatory Mechanisms in Links between Interpartner Aggression and Child Physiological Functioning

    ERIC Educational Resources Information Center

    Davies, Patrick T.; Sturge-Apple, Melissa L.; Cicchetti, Dante; Manning, Liviah G.; Zale, Emily

    2009-01-01

    Background: This paper examined children's fearful, sad, and angry reactivity to interparental conflict as mediators of associations between their exposure to interparental aggression and physiological functioning. Methods: Participants included 200 toddlers and their mothers. Assessments of interparental aggression and children's emotional…

  4. Evidence for Mito-Nuclear and Sex-Linked Reproductive Barriers between the Hybrid Italian Sparrow and Its Parent Species

    PubMed Central

    Sætre, Glenn-Peter; Bailey, Richard I.

    2014-01-01

    Studies of reproductive isolation between homoploid hybrid species and their parent species have rarely been carried out. Here we investigate reproductive barriers between a recently recognized hybrid bird species, the Italian sparrow Passer italiae and its parent species, the house sparrow P. domesticus and Spanish sparrow P. hispaniolensis. Reproductive barriers can be difficult to study in hybrid species due to lack of geographical contact between taxa. However, the Italian sparrow lives parapatrically with the house sparrow and both sympatrically and parapatrically with the Spanish sparrow. Through whole-transcriptome sequencing of six individuals of each of the two parent species we identified a set of putatively parent species-diagnostic single nucleotide polymorphism (SNP) markers. After filtering for coverage, genotyping success (>97%) and multiple SNPs per gene, we retained 86 species-informative, genic, nuclear and mitochondrial SNP markers from 84 genes for analysis of 612 male individuals. We show that a disproportionately large number of sex-linked genes, as well as the mitochondria and nuclear genes with mitochondrial function, exhibit sharp clines at the boundaries between the hybrid and the parent species, suggesting a role for mito-nuclear and sex-linked incompatibilities in forming reproductive barriers. We suggest that genomic conflict via interactions between mitochondria and sex-linked genes with mitochondrial function (“mother's curse”) at one boundary and centromeric drive at the other may best explain our findings. Hybrid speciation in the Italian sparrow may therefore be influenced by mechanisms similar to those involved in non-hybrid speciation, but with the formation of two geographically separated species boundaries instead of one. Spanish sparrow alleles at some loci have spread north to form reproductive barriers with house sparrows, while house sparrow alleles at different loci, including some on the same chromosome, have spread

  5. PCR–Enzyme-Linked Immunosorbent Assay for Detection and Identification of Campylobacter Species: Application to Isolates and Stool Samples

    PubMed Central

    Metherell, L. A.; Logan, J. M. J.; Stanley, J.

    1999-01-01

    We report a PCR–enzyme-linked immunosorbent assay which identifies Campylobacter species by capture hybridization of a single-stranded 16S rRNA gene amplicon with species-specific probes in a microtiter plate format. Specificities were confirmed for both reference and field strains, but the type strain of Campylobacter coli was atypical. The assay was rapid, informative, and usable with stool-extracted DNA. PMID:9889235

  6. [Effects of different barnyardgrass species on grain yield of rice and their physiological characteristics under alternate wetting and drying irrigation].

    PubMed

    Zhang, Zi-chang; Li, Yong-feng; Yang, Xia; Gu, Tao; Li, Gui

    2015-11-01

    In order to investigate the influence of different barnyardgrass species on rice yield and physiological characteristics of rice, two rice cultivars, Liangyoupeijiu (an indica hybrid cultivar) and Nanjing 9108 (a japonica cultivar) , were employed to co-culture with four barnyardgrass species during the period from transplanting to maturity under alternate wetting and moderate drying ir- rigation condition. The treatments were separately designed as follow: weed free ( control) , rice with Echinochloa crusgalli var. mitis (T1), rice with E. crusgalli (T2), rice with E. crusgali var. zelayensis (T3) and rice with E. colonum (T4). The results showed that T1, T2, T3 and T4 treatments reduced the Liangyoupeijiu yield by 13.8%, 10.6%, 23.8% and 0.5%, but the corresponding yield loss of Nanjing 9108 could reach up to 45.5%, 36.9%, 60.7% and 15.1%, respectively. The results above showed that T1, T2 and T3 treatments all significantly reduced grain yield, and T4 treatment only reduced grain yield for Nanjing 9108 but not for Liangyoupeijiu. All treatments elevated malondialehyde contents of rice leaf, but the activities of peroxidase, catalase, superoxide dimutase, dry matter accumulation in maturity stage, root oxidation activities and contents of indole-3-acetic acid as well as zeatin + zeatin riboside in roots during rice grain filling stage were all decreased. The influence degree of four barnyardgrass against physiological indices of rice had the order of T3 > T1 >T2 > T4. It showed that the reductions in enzyme activities of antioxidant system, root oxidation activities, contents of indole-3-acetic acid, zeatin + zeatin riboside during grain filling stage and accumulation of dry matter in maturity as well as increase in contents of malondialehyde of rice during grain filling stage might be important reasons for grain yield reduction when grew with barnyardgrass. PMID:26915195

  7. Different Growth and Physiological Responses to Cadmium of the Three Miscanthus Species

    PubMed Central

    Guo, Haipeng; Hong, Chuntao; Chen, Xiaomin; Xu, Yanxia; Liu, Yan; Jiang, Dean; Zheng, Bingsong

    2016-01-01

    Miscanthus has been proposed as a promising crop for phytoremediation due to its high biomass yield and remarkable adaptability to different environments. However, little is known about the resistance of Miscanthus spp. to cadmium (Cd). To determine any differences in resistance of Miscanthus to Cd, we examined plant growth, net photosynthetic rate (Pn), activities of anti-oxidant and C4 photosynthetic enzymes, concentrations of Cd in leaves and roots, and observed the chloroplast structure in three Miscanthus species treated with 0, 10, 50, 100 or 200 μM Cd in solutions. Miscanthus sinensis showed more sensitivity to Cd, including sharp decreases in growth, Pn, PEPC activity and damage to chloroplast structure, and the highest H2O2 and Cd concentrations in leaves and roots after Cd treatments. Miscanthus sacchariflorus showed higher resistance to Cd and better growth, had the highest Pn and phosphoenolpyruvate carboxylase (PEPC) activities and integrative chloroplast structure and the lowest hydrogen peroxide (H2O2) and leaf and root Cd concentrations. The results could play an important role in understanding the mechanisms of Cd tolerance in plants and in application of phytoremediation. PMID:27070918

  8. Different Growth and Physiological Responses to Cadmium of the Three Miscanthus Species.

    PubMed

    Guo, Haipeng; Hong, Chuntao; Chen, Xiaomin; Xu, Yanxia; Liu, Yan; Jiang, Dean; Zheng, Bingsong

    2016-01-01

    Miscanthus has been proposed as a promising crop for phytoremediation due to its high biomass yield and remarkable adaptability to different environments. However, little is known about the resistance of Miscanthus spp. to cadmium (Cd). To determine any differences in resistance of Miscanthus to Cd, we examined plant growth, net photosynthetic rate (Pn), activities of anti-oxidant and C4 photosynthetic enzymes, concentrations of Cd in leaves and roots, and observed the chloroplast structure in three Miscanthus species treated with 0, 10, 50, 100 or 200 μM Cd in solutions. Miscanthus sinensis showed more sensitivity to Cd, including sharp decreases in growth, Pn, PEPC activity and damage to chloroplast structure, and the highest H2O2 and Cd concentrations in leaves and roots after Cd treatments. Miscanthus sacchariflorus showed higher resistance to Cd and better growth, had the highest Pn and phosphoenolpyruvate carboxylase (PEPC) activities and integrative chloroplast structure and the lowest hydrogen peroxide (H2O2) and leaf and root Cd concentrations. The results could play an important role in understanding the mechanisms of Cd tolerance in plants and in application of phytoremediation. PMID:27070918

  9. Physiological and molecular changes in Oryza meridionalis Ng., a heat-tolerant species of wild rice

    PubMed Central

    Scafaro, Andrew P.; Haynes, Paul A.; Atwell, Brian J.

    2010-01-01

    Oryza meridionalis Ng. is a wild relative of Oryza sativa L. found throughout northern Australia where temperatures regularly exceed 35 °C in the monsoon growing season. Heat tolerance in O. meridionalis was established by comparing leaf elongation and photosynthetic rates at 45 °C with plants maintained at 27 °C. By comparison with O. sativa ssp. japonica cv. Amaroo, O. meridionalis was heat tolerant. Elongation rates of the third leaf of O. meridionalis declined by 47% over 24 h at 45 °C compared with a 91% decrease for O. sativa. Net photosynthesis was significantly higher in O. sativa at 27 °C whereas the two species had the same assimilation rates at 45 °C. The leaf proteome and expression levels of individual heat-responsive genes provided insight into the heat response of O. meridionalis. After 24 h of heat exposure, many enzymes involved in the Calvin Cycle were more abundant, while mRNA of their genes generally decreased. Ferredoxin-NADP(H) oxidoreductase, a key enzyme in photosynthetic electron transport had both reduced abundance and gene expression, suggesting light reactions were highly susceptible to heat stress. Rubisco activase was strongly up-regulated after 24 h of heat, with the large isoform having the largest relative increase in protein abundance and a significant increase in gene expression. The protective proteins Cpn60, Hsp90, and Hsp70 all increased in both protein abundance and gene expression. A thiamine biosynthesis protein (THI1), previously shown to act protectively against stress, increased in abundance during heat, even as thiamine levels fell in O. meridionalis. PMID:19819927

  10. LINKING SURFACE- AND GROUND- WATER LEVELS TO RIPARIAN GRASSLAND SPECIES ALONG THE PLATTE RIVER IN CENTRAL NEBRASKA

    EPA Science Inventory

    Ecologists use a host of techniques to quantify how plant species are linked to environmental gradients. Nearly all these techniques, however, produce results that represent gradients in general terms such as low to high elevation, xeric to mesic, and low to high concentration. W...

  11. The physiology of salinity tolerance in larvae of two species of Culex mosquitoes: the role of compatible solutes.

    PubMed

    Patrick, M L; Bradley, T J

    2000-02-01

    We investigated the physiological basis for differences in salinity tolerance ranges in mosquito larvae of the genus Culex. We examined the response of larvae of C. quinquefasciatus, a freshwater obligate, and C. tarsalis, a euryhaline osmoconformer, following transfer from fresh water to 34% sea water. Hemolymph Na(+) and Cl(-) levels increased similarly in both species, indicating that ion regulation does not differ under these conditions. C. quinquefasciatus responded to increased environmental salinity with increased hemolymph levels of serine, but suffered a significant reduction in levels of trehalose. C. tarsalis responded to increased environmental salinity with increased hemolymph levels of both proline and trehalose. When C. tarsalis larvae were held in 64% sea water, which C. quinquefasciatus larvae cannot tolerate, hemolymph proline and trehalose were accumulated approximately 50-fold and twofold, respectively, relative to freshwater values. We found that proline serves as both an intra- and extracellular compatible solute in C. tarsalis, the first such circumstance documented in an animal in response to increased environmental salinity. Analyses of the acute responses of the two species to an increase in salinity (from 30% to 50% sea water) indicate that larvae of C. tarsalis are able to volume-regulate via drinking and to attenuate increases in hemolymph NaCl concentration using unknown mechanisms during large, rapid increases in salinity. PMID:10648224

  12. Behavioral and physiological adjustments to new predators in an endemic island species, the Galápagos marine iguana.

    PubMed

    Berger, Silke; Wikelski, Martin; Romero, L Michael; Kalko, Elisabeth K V; Rödl, Thomas

    2007-12-01

    For the past 5 to 15 million years, marine iguanas (Amblyrhynchus cristatus), endemic to the Galápagos archipelago, experienced relaxed predation pressure and consequently show negligible anti-predator behavior. However, over the past few decades introduced feral cats and dogs started to prey on iguanas on some of the islands. We investigated experimentally whether behavioral and endocrine anti-predator responses changed in response to predator introduction. We hypothesized that flight initiation distances (FID) and corticosterone (CORT) concentrations should increase in affected populations to cope with the novel predators. Populations of marine iguanas reacted differentially to simulated predator approach depending on whether or not they were previously naturally exposed to introduced predators. FIDs were larger at sites with predation than at sites without predation. Furthermore, the occurrence of new predators was associated with increased stress-induced CORT levels in marine iguanas. In addition, age was a strong predictor of variation in FID and CORT levels. Juveniles, which are generally more threatened by predators compared to adults, showed larger FIDs and higher CORT baseline levels as well as higher stress-induced levels than adults. The results demonstrate that this naive island species shows behavioral and physiological plasticity associated with actual predation pressure, a trait that is presumably adaptive. However, the adjustments in FID are not sufficient to cope with the novel predators. We suggest that low behavioral plasticity in the face of introduced predators may drive many island species to extinction. PMID:17904141

  13. Anatomical and physiological regulation of post-fire carbon and water exchange in canopies of two resprouting Eucalyptus species.

    PubMed

    Turnbull, Tarryn L; Buckley, Thomas N; Barlow, Alexandra M; Adams, Mark A

    2014-10-01

    The great majority of Eucalyptus spp. are facultative resprouters, and they dominate the eucalypt forests of Australia. Despite this numeric and geographic dominance, there is a general lack of knowledge of their capacity for carbon capture and water loss during canopy reinstation. After a crown-removing fire, we measured leaf-level determinants of carbon and water flux in resprouting canopies of Eucalyptus dives and E. radiata over the 3 years that followed. Leaf anatomy and physiology changed markedly during canopy reinstation, and leaves produced in the second year (2010) were distinct from those produced later. Leaves produced in 2010 were thicker (all measures of leaf anatomy), yet more porous (increased intercellular airspace), causing specific leaf area also to be greater. Indicators of heterotrophic activity, leaf respiration rate and light compensation point, were twofold greater in 2010, whereas all measures of photosynthetic capacity were greatest in leaves produced in 2011 and 2012. Whilst stomatal density, vein density and leaf hydraulic conductance all progressively decreased with time, neither leaf water status nor carbon isotope discrimination were affected. We conclude that canopy reinstation is primarily limited by pre-fire carbon stores, rather than by post-fire edaphic conditions (e.g., water availability), and thus argue that capacity for recovery is directly linked to pre-fire forest health. PMID:25108550

  14. Biological consilience of hydrogen sulfide and nitric oxide in plants: Gases of primordial earth linking plant, microbial and animal physiologies.

    PubMed

    Yamasaki, Hideo; Cohen, Michael F

    2016-05-01

    Hydrogen sulfide (H2S) is produced in the mammalian body through the enzymatic activities of cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3MST). A growing number of studies have revealed that biogenic H2S produced in tissues is involved in a variety of physiological responses in mammals including vasorelaxation and neurotransmission. It is now evident that mammals utilize H2S to regulate multiple signaling systems, echoing the research history of the gaseous signaling molecules nitric oxide (NO) and carbon monoxide (CO) that had previously only been recognized for their cytotoxicity. In the human diet, meats (mammals, birds and fishes) and vegetables (plants) containing cysteine and other sulfur compounds are the major dietary sources for endogenous production of H2S. Plants are primary producers in ecosystems on the earth and they synthesize organic sulfur compounds through the activity of sulfur assimilation. Although plant H2S-producing activities have been known for a long time, our knowledge of H2S biology in plant systems has not been updated to the extent of mammalian studies. Here we review recent progress on H2S studies, highlighting plants and bacteria. Scoping the future integration of H2S, NO and O2 biology, we discuss a possible linkage between physiology, ecology and evolutional biology of gas metabolisms that may reflect the historical changes of the Earth's atmospheric composition. PMID:27083071

  15. Linking mycorrhizas to sporocarps: a new species, Geopora cercocarpi, on Cercocarpus ledifolius (Rosaceae).

    PubMed

    Southworth, Darlene; Frank, Jonathan L

    2011-01-01

    Mycorrhizal assemblages characterized by molecular data frequently differ from collections of mycorrhizal sporocarps at the same site. Geopora species are frequent mycobionts of ectomycorrhizal roots, but except for G. cooperi they are rarely identified to species by molecular methods. Among the mycobionts of ectomycorrhizas with Cercocarpus ledifolius (Rosaceae) was a fungal species with a 91% BLAST match to G. arenicola. To determine the species of Geopora we surveyed for hypogeous sporocarps under C. ledifolius at sites in southern Oregon where the Geopora mycorrhizas had been collected and identified by DNA sequences of the ITS region. We found sporocarps of a Geopora species with 100% BLAST match to the mycorrhizas. Morphological characters of a white hymenium, inrolled entire margin and large spores, along with a hypogeous habit and a mycorrhizal host of C. ledifolius, distinguished these specimens from previously described species. Here we describe a new species, Geopora cercocarpi. PMID:21700635

  16. Proteomic analysis of the venom from the scorpion Tityus stigmurus: biochemical and physiological comparison with other Tityus species.

    PubMed

    Batista, C V F; Román-González, S A; Salas-Castillo, S P; Zamudio, F Z; Gómez-Lagunas, F; Possani, L D

    2007-01-01

    The venom from the Brazilian scorpion Tityus stigmurus was fractionated by high performance liquid chromatography (HPLC) and the corresponding components were used for molecular mass determination using electrospray ion trap mass spectrometry. One hundred distinct components were clearly assigned showing molecular masses from 216.5 to 44,800.0 Da. Fifteen new components were isolated and sequenced, four of them to completion: Tst-3 (similar to Na(+) channel specific scorpion toxins), Tst-17 (a K(+) channel blocking peptide similar to Tc1), Tst beta KTx (a peptide with identical sequence as that of TsTX-K beta toxin earlier described to exist in T. serrulatus venom) and finally a novel proline-rich peptide of unknown function. Among the eleven components partially sequenced were two enzymes: hyaluronidase and lysozyme. The first enzyme has a molecular mass of 44,800.0 Da. This enzyme showed high activity against the substrate hyaluronan in vitro. Amino acid sequence of the second enzyme showed that it is similar to other known lysozymes, with similar molecular mass and sequence to that of bona fide lysozymes reported in public protein data banks. Finally, this communication reports a correlation among HPLC retention times and molecular masses of folded scorpion toxins as well as a comparative structural and physiological analysis of components from the venom of several species of the genus Tityus. PMID:17270501

  17. A comparative analysis of transcriptomic, biochemical and physiological responses to elevated ozone identifies species-specific mechanisms of resilience in legume crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current concentrations of tropospheric ozone (O3) pollution negatively impact plant metabolism, which can result in decreased crop yields. Interspecific variation in the physiological response of plants to elevated [O3] exists; however, the underlying cellular responses explaining species-specific d...

  18. Are parasite richness and abundance linked to prey species richness and individual feeding preferences in fish hosts?

    PubMed

    Cirtwill, Alyssa R; Stouffer, Daniel B; Poulin, Robert; Lagrue, Clément

    2016-01-01

    Variations in levels of parasitism among individuals in a population of hosts underpin the importance of parasites as an evolutionary or ecological force. Factors influencing parasite richness (number of parasite species) and load (abundance and biomass) at the individual host level ultimately form the basis of parasite infection patterns. In fish, diet range (number of prey taxa consumed) and prey selectivity (proportion of a particular prey taxon in the diet) have been shown to influence parasite infection levels. However, fish diet is most often characterized at the species or fish population level, thus ignoring variation among conspecific individuals and its potential effects on infection patterns among individuals. Here, we examined parasite infections and stomach contents of New Zealand freshwater fish at the individual level. We tested for potential links between the richness, abundance and biomass of helminth parasites and the diet range and prey selectivity of individual fish hosts. There was no obvious link between individual fish host diet and helminth infection levels. Our results were consistent across multiple fish host and parasite species and contrast with those of earlier studies in which fish diet and parasite infection were linked, hinting at a true disconnect between host diet and measures of parasite infections in our study systems. This absence of relationship between host diet and infection levels may be due to the relatively low richness of freshwater helminth parasites in New Zealand and high host-parasite specificity. PMID:26573385

  19. Brood Parasitism Is Linked to Egg Pattern Diversity within and among Species of Australian Passerines.

    PubMed

    Medina, Iliana; Troscianko, Jolyon; Stevens, Martin; Langmore, Naomi E

    2016-03-01

    Bird eggs show striking diversity in color and pattern. One explanation for this is that interactions between avian brood parasites and their hosts drive egg phenotype evolution. Brood parasites lay their eggs in the nests of other species, their hosts. Many hosts defend their nests against parasitism by rejecting foreign eggs, which selects for parasite eggs that mimic those of the host. In theory, this may in turn select for changes in host egg phenotypes over time to facilitate discrimination of parasite eggs. Here, we test for the first time whether parasitism by brood parasites has led to increased divergence in egg phenotype among host species. Using Australian host and nonhost species and objective measures of egg color and pattern, we show that (i) hosts of brood parasites have higher within-species variation in egg pattern than nonhosts, supporting previous findings in other systems, and (ii) host species have diverged more in their egg patterns than nonhost species after controlling for divergence time. Overall, our results suggest that brood parasitism has played a significant role in the evolution of egg diversity and that these effects are evident, not only within species, but also among species. PMID:26913947

  20. Fine-scale community and genetic structure are tightly linked in species-rich grasslands

    PubMed Central

    Whitlock, Raj; Bilton, Mark C.; Grime, J. Phil; Burke, Terry

    2011-01-01

    Recent evidence indicates that grassland community structure and species diversity are influenced by genetic variation within species. We review what is known regarding the impact of intraspecific diversity on grassland community structure, using an ancient limestone pasture as a focal example. Two genotype-dependent effects appear to modify community structure in this system. First, the abundance of individual constituent species can depend upon the combined influence of direct genetic effects stemming from individuals within the population. Second, the outcome of localized interspecific interactions occurring within the community can depend on the genotypes of participating individuals (indicating indirect genetic effects). Only genotypic interactions are thought to be capable of allowing the long-term coexistence of both genotypes and species. We discuss the implications of these effects for the maintenance of diversity in grasslands. Next, we present new observations indicating that losses of genotypic diversity from each of two species can be predicted by the abundance of other coexisting species within experimental grassland communities. These results suggest genotype-specific responses to abundance in other coexisting species. We conclude that both direct and indirect genetic effects are likely to shape community structure and species coexistence in grasslands, implying tight linkage between fine-scale genetic and community structure. PMID:21444309

  1. Linking climate change and biological invasions: Ocean warming facilitates nonindigenous species invasions.

    PubMed

    Stachowicz, John J; Terwin, Jeffrey R; Whitlatch, Robert B; Osman, Richard W

    2002-11-26

    The spread of exotic species and climate change are among the most serious global environmental threats. Each independently causes considerable ecological damage, yet few data are available to assess whether changing climate might facilitate invasions by favoring introduced over native species. Here, we compare our long-term record of weekly sessile marine invertebrate recruitment with interannual variation in water temperature to assess the likely effect of climate change on the success and spread of introduced species. For the three most abundant introduced species of ascidian (sea squirt), the timing of the initiation of recruitment was strongly negatively correlated with winter water temperature, indicating that invaders arrived earlier in the season in years with warmer winters. Total recruitment of introduced species during the following summer also was positively correlated with winter water temperature. In contrast, the magnitude of native ascidian recruitment was negatively correlated with winter temperature (more recruitment in colder years) and the timing of native recruitment was unaffected. In manipulative laboratory experiments, two introduced compound ascidians grew faster than a native species, but only at temperatures near the maximum observed in summer. These data suggest that the greatest effects of climate change on biotic communities may be due to changing maximum and minimum temperatures rather than annual means. By giving introduced species an earlier start, and increasing the magnitude of their growth and recruitment relative to natives, global warming may facilitate a shift to dominance by nonnative species, accelerating the homogenization of the global biota. PMID:12422019

  2. Hemolymph metabolites and osmolality are tightly linked to cold tolerance of Drosophila species: a comparative study.

    PubMed

    Olsson, Trine; MacMillan, Heath A; Nyberg, Nils; Staerk, Dan; Malmendal, Anders; Overgaard, Johannes

    2016-08-15

    Drosophila, like most insects, are susceptible to low temperatures, and will succumb to temperatures above the freezing point of their hemolymph. For these insects, cold exposure causes a loss of extracellular ion and water homeostasis, leading to chill injury and eventually death. Chill-tolerant species are characterized by lower hemolymph [Na(+)] than chill-susceptible species and this lowered hemolymph [Na(+)] is suggested to improve ion and water homeostasis during cold exposure. It has therefore also been hypothesized that hemolymph Na(+) is replaced by other 'cryoprotective' osmolytes in cold-tolerant species. Here, we compared the hemolymph metabolite profiles of five drosophilid species with marked differences in chill tolerance. All species were examined under 'normal' thermal conditions (i.e. 20°C) and following cold exposure (4 h at 0°C). Under benign conditions, total hemolymph osmolality was similar among all species despite chill-tolerant species having lower hemolymph [Na(+)]. Using NMR spectroscopy, we found that chill-tolerant species instead have higher levels of sugars and free amino acids in their hemolymph, including classical 'cryoprotectants' such as trehalose and proline. In addition, we found that chill-tolerant species maintain a relatively stable hemolymph osmolality and metabolite profile when exposed to cold stress while sensitive species suffer from large increases in osmolality and massive changes in their metabolic profiles during a cold stress. We suggest that the larger contribution of classical cryoprotectants in chill-tolerant Drosophila plays a non-colligative role for cold tolerance that contributes to osmotic and ion homeostasis during cold exposure and, in addition, we discuss how these comparative differences may represent an evolutionary pathway toward more extreme cold tolerance of insects. PMID:27307488

  3. Acyl Carrier Protein Synthases from Gram-Negative, Gram-Positive, and Atypical Bacterial Species: Biochemical and Structural Properties and Physiological Implications

    PubMed Central

    McAllister, Kelly A.; Peery, Robert B.; Zhao, Genshi

    2006-01-01

    Acyl carrier protein (ACP) synthase (AcpS) catalyzes the transfer of the 4′-phosphopantetheine moiety from coenzyme A (CoA) onto a serine residue of apo-ACP, resulting in the conversion of apo-ACP to the functional holo-ACP. The holo form of bacterial ACP plays an essential role in mediating the transfer of acyl fatty acid intermediates during the biosynthesis of fatty acids and phospholipids. AcpS is therefore an attractive target for therapeutic intervention. In this study, we have purified and characterized the AcpS enzymes from Escherichia coli, Streptococcus pneumoniae, and Mycoplasma pneumoniae, which exemplify gram-negative, gram-positive, and atypical bacteria, respectively. Our gel filtration column chromatography and cross-linking studies demonstrate that the AcpS enzyme from M. pneumoniae, like E. coli enzyme, exhibits a homodimeric structure, but the enzyme from S. pneumoniae exhibits a trimeric structure. Our biochemical studies show that the AcpS enzymes from M. pneumoniae and S. pneumoniae can utilize both short- and long-chain acyl CoA derivatives but prefer long-chain CoA derivatives as substrates. On the other hand, the AcpS enzyme from E. coli can utilize short-chain CoA derivatives but not the long-chain CoA derivatives tested. Finally, our biochemical studies show that M. pneumoniae AcpS is kinetically a very sluggish enzyme compared with those from E. coli and S. pneumoniae. Together, the results of these studies show that the AcpS enzymes from different bacterial species exhibit different native structures and substrate specificities with regard to the utilization of CoA and its derivatives. These findings suggest that AcpS from different microorganisms plays a different role in cellular physiology. PMID:16788183

  4. Linking Xylem Hydraulic Conductivity and Vulnerability to the Leaf Economics Spectrum—A Cross-Species Study of 39 Evergreen and Deciduous Broadleaved Subtropical Tree Species

    PubMed Central

    Kröber, Wenzel; Zhang, Shouren; Ehmig, Merten; Bruelheide, Helge

    2014-01-01

    While the fundamental trade-off in leaf traits related to carbon capture as described by the leaf economics spectrum is well-established among plant species, the relationship of the leaf economics spectrum to stem hydraulics is much less known. Since carbon capture and transpiration are coupled, a close connection between leaf traits and stem hydraulics should be expected. We thus asked whether xylem traits that describe drought tolerance and vulnerability to cavitation are linked to particular leaf traits. We assessed xylem vulnerability, using the pressure sleeve technique, and anatomical xylem characteristics in 39 subtropical tree species grown under common garden conditions in the BEF-China experiment and tested for correlations with traits related to the leaf economics spectrum as well as to stomatal control, including maximum stomatal conductance, vapor pressure deficit at maximum stomatal conductance and vapor pressure deficit at which stomatal conductance is down-regulated. Our results revealed that specific xylem hydraulic conductivity and cavitation resistance were closely linked to traits represented in the leaf economic spectrum, in particular to leaf nitrogen concentration, as well as to log leaf area and leaf carbon to nitrogen ratio but not to any parameter of stomatal conductance. The study highlights the potential use of well-known leaf traits from the leaf economics spectrum to predict plant species' drought resistance. PMID:25423316

  5. Cytochrome b Divergence between Avian Sister Species Is Linked to Generation Length and Body Mass

    PubMed Central

    Thomson, Caroline E.; Gilbert, James D. J.; Brooke, M. de L

    2014-01-01

    It is increasingly realised that the molecular clock does not tick at a constant rate. Rather, mitochondrial mutation rates are influenced by factors such as generation length and body mass. This has implications for the use of genetic data in species delimitation. It could be that speciation, as recognised by avian taxonomists, is associated with a certain minimum genetic distance between sister taxa, in which case we would predict no difference in the cytochrome b divergence of sister taxa according to the species' body size or generation time. Alternatively, if what taxonomists recognise as speciation has tended to be associated with the passage of a minimum amount of time since divergence, then there might be less genetic divergence between sister taxa with slower mutation rates, namely those that are heavier and/or with longer generation times. After excluding non-flying species, we analysed a database of over 600 avian sister species pairs, and found that species pairs with longer generation lengths (which tend to be the larger species) showed less cytochrome b divergence. This finding cautions against using any simple unitary criterion of genetic divergence to delimit species. PMID:24505250

  6. Linking El Niño, local rainfall, and migration timing in a tropical migratory species.

    PubMed

    Shaw, Allison K; Kelly, Kathryn A

    2013-11-01

    Current climate models project changes in both temperature and precipitation patterns across the globe in the coming years. Migratory species, which move to take advantage of seasonal climate patterns, are likely to be affected by these changes, and indeed, a number of studies have shown a relationship between changing climate and the migration timing of various species. However, these studies have almost exclusively focused on the effects of temperature change on species that inhabit temperate zones. Here, we explore the relationship between rainfall and migration timing in a tropical species, Gecarcoidea natalis (Christmas Island red crab). We find that the timing of the annual crab breeding migration is closely related to the amount of rain that falls during a 'migration window' period prior to potential egg release dates, which is in turn related to the Southern Oscillation Index, an atmospheric El Niño-Southern Oscillation Index. As reproduction in this species is conditional on successful migration, major changes in migration patterns could have detrimental consequences for the survival of the species. This study serves to broaden our understanding of the effects of climate change on migratory species and will hopefully inspire future work on rainfall and tropical migrations. PMID:23821605

  7. Sex-linked markers and microsatellite locus duplication in the cichlid species Oreochromis tanganicae.

    PubMed

    Cnaani, Avner; Kocher, Thomas D

    2008-12-23

    Cichlid species of the genus Oreochromis vary in their genetic sex-determination systems. In this study, we used microsatellite DNA markers to characterize the sex-determination system in Oreochromis tanganicae. Markers on linkage group 3 were associated with phenotypic sex, with an inheritance pattern typical of a female heterogametic species (WZ-ZZ). Further, locus duplication was observed for two separate microsatellite markers on the sex chromosome. These results further advance our understanding of the rapidly evolving sex-determination systems among these closely related tilapia species. PMID:18700198

  8. Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots.

    PubMed

    Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

    2013-03-01

    Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava. PMID:23344905

  9. Species turnover (β-diversity) in ectomycorrhizal fungi linked to NH4+ uptake capacity.

    PubMed

    Kranabetter, J M; Hawkins, B J; Jones, M D; Robbins, S; Dyer, T; Li, T

    2015-12-01

    Ectomycorrhizal (EcM) fungal communities may be shaped by both deterministic and stochastic processes, potentially influencing ecosystem development and function. We evaluated community assembly processes for EcM fungi of Pseudotsuga menziesii among 12 sites up to 400 km apart in southwest British Columbia (Canada) by investigating species turnover (β-diversity) in relation to soil nitrogen (N) availability and physical distance. We then examined functional traits for an N-related niche by quantifying net fluxes of NH4+, NO3- and protons on excised root tips from three contrasting sites using a microelectrode ion flux measurement system. EcM fungal communities were well aligned with soil N availability and pH, with no effect of site proximity (distance-decay curve) on species assemblages. Species turnover was significant (β(1/2) = 1.48) along soil N gradients, with many more Tomentella species on high N than low N soils, in contrast to Cortinarius species. Ammonium uptake was greatest in the spring on the medium and rich sites and averaged over 190 nmol/m(2)/s for Tomentella species. The lowest uptake rates of NH4+ were by nonmycorrhizal roots of axenically grown seedlings (10 nmol/m(2)/s), followed by Cortinarius species (60 nmol/m(2)/s). EcM roots from all sites displayed only marginal uptake of nitrate (8.3 nmol/m(2)/s). These results suggest NH4+ uptake capacity is an important functional trait influencing the assembly of EcM fungal communities. The diversity of EcM fungal species across the region arguably provides critical belowground adaptations to organic and inorganic N supply that are integral to temperate rainforest ecology. PMID:26507980

  10. Comparative studies on plant range size: Linking reproductive and regenerative traits in two Ipomoea species

    NASA Astrophysics Data System (ADS)

    Astegiano, Julia; Funes, Guillermo; Galetto, Leonardo

    2010-09-01

    Reproductive and regenerative traits associated with colonization and persistence ability may determine plant range size. However, few comparative studies on plant distribution have assessed these traits simultaneously. Pollinator richness and frequency of visits, autonomous self-pollination ability, reproductive output (i.e., reproductive traits), seed bank strategy and seedling density (i.e., regenerative traits) were compared between the narrowly distributed Ipomoea rubriflora O'Donnell (Convolvulaceae) and its widespread congener Ipomoea purpurea (L.) Roth. The narrowly distributed species showed higher ecological specialization to pollinators and lower autonomous self-pollination ability. Frequency of visits, natural seed/ovule ratio and fruit set, and total fruit production did not differ between species. However, the number of seeds produced per fruit was lower in the narrowly distributed species, translating into lower total seed production per plant. Indeed, I. rubriflora formed smaller transient and persistent seed banks and showed lower seedling density than the widespread I. purpurea. These reproductive and regenerative trait results suggest that the narrowly distributed species may have lower colonization and persistence ability than its widespread congener. They further suggest that the negative effects of lower fecundity in the narrowly distributed species might persist in time through the long-lasting effects of total seed production on seed bank size, reducing the species' ability to buffered environmental stochasticity. However, other regenerative traits, such as seed size, and processes such as pre- and post-dispersal seed predation, might modulate the effects of plant fecundity on plant colonization and persistence ability and thus range size.

  11. Conservation physiology

    PubMed Central

    Kronfeld-Schor, Noga

    2014-01-01

    Global change presents a huge and exciting challenge to the study of thermal physiology. The implication of thermoregulatory strategies and abilities for the survival of individuals and species, are of high importance for predicting species response to global change challenges and ways to mitigate them, and for conservation acts. A good example of such a study is the paper by Cooper and Withers in this issue.1

  12. Linking chlorophyll fluorescence, hyperspectral reflectance and plant physiological responses to detect stress using the photochemical reflectance index (PRI) (Invited)

    NASA Astrophysics Data System (ADS)

    Naumann, J. C.; Young, D.; Anderson, J.

    2009-12-01

    The concept of using vegetation as sentinels to indicate natural or anthropogenic stress is not new and could potentially provide an ideal mechanism for large-scale detection. Advances in fluorescence spectroscopy and reflectance-derived fluorescence have made possible earlier detection of stress in plants, especially before changes in chlorophyll content are visible. Our studies have been used to fuse leaf fluorescence and reflectance characteristics to remotely sense and rapidly detect vegetation stress and terrain characteristics. Laboratory studies have indicated that light-adapted fluorescence (ΔF/F‧m) measurements have been successful in all experiments at detecting stress from flooding, salinity, drought, herbicide and TNT contamination prior to visible signs of damage. ΔF/F‧m was related to plant physiological status in natural stress conditions, as seen in the relationships with stomatal conductance and photosynthesis The photochemical reflectance index (PRI) and other reflectance ratios were effective at tracking changes in ΔF/F‧m at the leaf and canopy-level scales. At the landscape-level, chlorophyll fluorescence and airborne reflectance imagery were used to evaluate spatial variations in stress in the dominant shrub on a barrier island, Myrica cerifera, during a severe drought and compared to an extremely wet year. Measurements of relative water content and the water band index (WBI970) indicated that water stress did not vary across the island. In contrast, there were significant differences in tissue chlorides across sites. Using PRI we were able to detect salinity stress across the landscape. PRI did not differ between wet and dry years. There was a positive relationship between PRI and ΔF/F‧m for M. cerifera (r2 = 0.79). The normalized difference vegetation index (NDVI), the chlorophyll index (CI) and WBI970 were higher during the wet summer but varied little across the island. PRI was not significantly related to NDVI, suggesting that

  13. Linking climate change and karst hydrology to evaluate species vulnerability: The Edwards and Madison aquifers (Invited)

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Long, A. J.; Stamm, J. F.; Poteet, M.; Symstad, A.

    2013-12-01

    Karst aquifers present an extreme case of flow along structurally variable pathways, making them highly dynamic systems and therefore likely to respond rapidly to climate change. In turn, many biological communities and ecosystems associated with karst are sensitive to hydrologic changes. We explored how three sites in the Edwards aquifer (Texas) and two sites in the Madison aquifer (South Dakota) might respond to projected climate change from 2011 to 2050. Ecosystems associated with these karst aquifers support federally listed endangered and threatened species and state-listed species of concern, including amphibians, birds, insects, and plants. The vulnerability of selected species associated with projected climate change was assessed. The Advanced Research Weather and Research Forecasting (WRF) model was used to simulate projected climate at a 36-km grid spacing for three weather stations near the study sites, using boundary and initial conditions from the global climate model Community Climate System Model (CCSM3) and an A2 emissions scenario. Daily temperature and precipitation projections from the WRF model were used as input for the hydrologic Rainfall-Response Aquifer and Watershed Flow (RRAWFLOW) model and the Climate Change Vulnerability Index (CCVI) model. RRAWFLOW is a lumped-parameter model that simulates hydrologic response at a single site, combining the responses of quick and slow flow that commonly characterize karst aquifers. CCVI uses historical and projected climate and hydrologic metrics to determine the vulnerability of selected species on the basis of species exposure to climate change, sensitivity to factors associated with climate change, and capacity to adapt to climate change. An upward trend in temperature was projected for 2011-2050 at all three weather stations; there was a trend (downward) in annual precipitation only for the weather station in Texas. A downward trend in mean annual spring flow or groundwater level was projected for

  14. Linking environmental drivers with amphibian species diversity in ponds from subtropical grasslands.

    PubMed

    Gonçalves, Darlene S; Crivellari, Lucas B; Conte, Carlos Eduardo

    2015-09-01

    Amphibian distribution patterns are known to be influenced by habitat diversity at breeding sites. Thus, breeding sites variability and how such variability influences anuran diversity is important. Here, we examine which characteristics at breeding sites are most influential on anuran diversity in grasslands associated with Araucaria forest, southern Brazil, especially in places at risk due to anthropic activities. We evaluate the associations between habitat heterogeneity and anuran species diversity in nine body of water from September 2008 to March 2010, in 12 field campaigns in which 16 species of anurans were found. Of the seven habitat descriptors we examined, water depth, pond surface area and distance to the nearest forest fragment explained 81% of total species diversity. Water depth, margin vegetation type, surface area and distance to the next body of water explained between 31-74% of the variance in abundance of nine of the 16 species. Thus, maintenance of body of water, of the vegetation along the water edge and natural forest fragments in the grasslands, along with fire control (used to renovation of pasture), are fundamentally important for the maintenance of anuran species diversity through the conservation of their breeding sites. PMID:26421457

  15. Unsuppressed lipolysis in adipocytes is linked with enhanced gluconeogenesis and altered bile acid physiology in InsrP1195L/+ mice fed high-fat-diet

    PubMed Central

    Lee, Eun Young; Sakurai, Kenichi; Zhang, Xilin; Toda, Chitoku; Tanaka, Tomoaki; Jiang, Meizi; Shirasawa, Takuji; Tachibana, Kaori; Yokote, Koutaro; Vidal-Puig, Antonio; Minokoshi, Yasuhiko; Miki, Takashi

    2015-01-01

    High-fat diet (HFD) triggers insulin resistance and diabetes mellitus, but their link remains unclear. Characterization of overt hyperglycemia in insulin receptor mutant (InsrP1195L/+) mice exposed to HFD (InsrP1195L/+/HFD mice) revealed increased glucose-6-phosphatase (G6pc) expression in liver and increased gluconeogenesis from glycerol. Lipolysis in white adipose tissues (WAT) and lipolysis-induced blood glucose rise were increased in InsrP1195L/+/HFD mice, while wild-type WAT transplantation ameliorated the hyperglycemia and the increased G6pc expression. We found that the expressions of genes involved in bile acid (BA) metabolism were altered in InsrP1195L/+/HFD liver. Among these, the expression of Cyp7a1, a BA synthesis enzyme, was insulin-dependent and was markedly decreased in InsrP1195L/+/HFD liver. Reduced Cyp7a1 expression in InsrP1195L/+/HFD liver was rescued by WAT transplantation, and the expression of Cyp7a1 was suppressed by glycerol administration in wild-type liver. These findings suggest that unsuppressed lipolysis in adipocytes elicited by HFD feeding is linked with enhanced gluconeogenesis from glycerol and with alterations in BA physiology in InsrP1195L/+/HFD liver. PMID:26615883

  16. The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae).

    PubMed

    Mackenzie, Berin D E; Auld, Tony D; Keith, David A; Hui, Francis K C; Ooi, Mark K J

    2016-01-01

    Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

  17. The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae)

    PubMed Central

    Auld, Tony D.; Keith, David A.; Hui, Francis K. C.; Ooi, Mark K. J.

    2016-01-01

    Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

  18. Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

    PubMed

    Rivas-Ubach, Albert; Hódar, José A; Sardans, Jordi; Kyle, Jennifer E; Kim, Young-Mo; Oravec, Michal; Urban, Otmar; Guenther, Alex; Peñuelas, Josep

    2016-07-01

    The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but also the entire metabolome. Metabolomes are the final products of genotypes and are constrained by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from three closely related Pinus species with distant coevolutionary histories with the caterpillar of the processionary moth respond similarly to its attack. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of terpenes were in the attacked trees supporting the hypothesis that herbivores avoid plant individuals with higher concentrations. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution. PMID:27386082

  19. Investigation of the link between avian vacuolar myelinopathy and a novel species of cyanobacteria through laboratory feeding trials.

    PubMed

    Wiley, Faith E; Wilde, Susan B; Birrenkott, Anna H; Williams, Sarah K; Murphy, Thomas M; Hope, Charlotte P; Bowerman, William W; Fischer, John R

    2007-07-01

    Avian vacuolar myelinopathy (AVM) is a neurologic disease affecting Bald Eagles (Haliaeetus leucocephalus), American Coots (Fulica americana), and other birds in the southeastern United States. The cause of the disease has not yet been determined, although it is generally thought to be a natural toxin. Previous studies have linked AVM to aquatic vegetation, and the current working hypothesis is that a species of cyanobacteria growing epiphytically on that vegetation is producing a toxin that causes AVM. Surveys of epiphytic communities have identified a novel species of cyanobacteria in the order Stigonematales as the most likely suspect. The purpose of this study was to further examine the relationship between the suspect Stigonematales species and induction of AVM, by using animal feeding trials. Adult Mallards and domestic chickens were fed aquatic vegetation from two study sites containing the suspect cyanobacterial epiphyte, as well as a control site that did not contain the Stigonematales species. Two trials were conducted. The first trial used vegetation collected during mid-October 2003, and the second trial used vegetation collected during November and December 2003. Neither treatment nor control birds in the first trial developed AVM lesions. Ten of 12 treatment Mallards in the second trial were diagnosed with AVM, and control birds were not affected. This study provides further evidence that the novel Stigonematales species may be involved with AVM induction, or at the least it is a good predictor of AVM toxin presence in a system. The results also demonstrate the seasonal nature of AVM events. PMID:17699072

  20. LINKING PLANT TRAITS TO SPECIES PERFORMANCE IN REMNANT AND RESTORED INLAND SALT MARSH COMMUNITIES

    EPA Science Inventory

    This research will build upon prior efforts where regression was used to model salt marsh species persistence and productivity along hydrologic and edaphic gradients at the SWB. Upcoming results will enable the optimization of planting combinations at a given salinity leve...

  1. Modeling human congenital disorder of glycosylation type IIa in the mouse: conservation of asparagine-linked glycan-dependent functions in mammalian physiology and insights into disease pathogenesis.

    PubMed

    Wang, Y; Tan, J; Sutton-Smith, M; Ditto, D; Panico, M; Campbell, R M; Varki, N M; Long, J M; Jaeken, J; Levinson, S R; Wynshaw-Boris, A; Morris, H R; Le, D; Dell, A; Schachter, H; Marth, J D

    2001-12-01

    The congenital disorders of glycosylation (CDGs) are recent additions to the repertoire of inherited human genetic diseases. Frequency of CDGs is unknown since most cases are believed to be misdiagnosed or unrecognized. With few patients identified and heterogeneity in disease signs noted, studies of animal models may provide increased understanding of pathogenic mechanisms. However, features of mammalian glycan biosynthesis and species-specific variations in glycan repertoires have cast doubt on whether animal models of human genetic defects in protein glycosylation will reproduce pathogenic events and disease signs. We have introduced a mutation into the mouse germline that recapitulates the glycan biosynthetic defect responsible for human CDG type IIa (CDG-IIa). Mice lacking the Mgat2 gene were deficient in GlcNAcT-II glycosyltransferase activity and complex N-glycans, resulting in severe gastrointestinal, hematologic, and osteogenic abnormalities. With use of a lectin-based diagnostic screen for CDG-IIa, we found that all Mgat2-null mice died in early postnatal development. However, crossing the Mgat2 mutation into a distinct genetic background resulted in a low frequency of survivors. Mice deficient in complex N-glycans exhibited most CDG-IIa disease signs; however, some signs were unique to the aged mouse or are prognostic in human CDG-IIa. Unexpectedly, analyses of N-glycan structures in Mgat2-null mice revealed a novel oligosaccharide branch on the "bisecting" N-acetylglucosamine. These genetic, biochemical, and physiologic studies indicate conserved functions for N-glycan branches produced in the Golgi apparatus among two mammalian species and suggest possible therapeutic approaches to GlcNAcT-II deficiency. Our findings indicate that human genetic disease due to aberrant protein glycosylation can be modeled in the mouse to gain insights into N-glycan-dependent physiology and the pathogenesis of CDG-IIa. PMID:11805078

  2. Eco-Physiological Responses of Dominant Species to Watering in a Natural Grassland Community on the Semi-Arid Loess Plateau of China.

    PubMed

    Niu, Furong; Duan, Dongping; Chen, Ji; Xiong, Peifeng; Zhang, He; Wang, Zhi; Xu, Bingcheng

    2016-01-01

    Altered precipitation regimes significantly affect ecosystem structure and function in arid and semi-arid regions. In order to investigate effects of precipitation changes on natural grassland community in the semi-arid Loess Plateau, the current research examined eco-physiological characteristics of two co-dominant species (i.e., Bothriochloa ischaemum and Lespedeza davurica) and community composition following two watering instances (i.e., precipitation pulses, July and August, 2011, respectively) in a natural grassland community. Results showed that the photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration rapidly increased on the first to third day following watering in both species, and both months. Under watering treatments, the maximum net photosynthetic rates appeared on the second to third day after watering, which increased 30-80% in B. ischaemum and 40-50% in L. davurica compared with non-watering treatments, respectively. Leaf water use efficiency kept stable or initially decreased in both species under watering treatments. Watering in July produced more promoting effects on grass photosynthesis than in August, particularly in B. ischaemum. Community above-ground biomass at the end of the growing season increased after watering, although no significant changes in species diversity were observed. Our results indicated that timing and magnitude of watering could significantly affect plant eco-physiological processes, and there were species-specific responses in B. ischaemum and L. davurica. Pulsed watering increased community productivity, while did not significantly alter community composition after one growing season. The outcomes of this study highlight eco-physiological traits in dominant species may playing important roles in reshaping community composition under altered precipitation regimes. PMID:27242864

  3. Eco-Physiological Responses of Dominant Species to Watering in a Natural Grassland Community on the Semi-Arid Loess Plateau of China

    PubMed Central

    Niu, Furong; Duan, Dongping; Chen, Ji; Xiong, Peifeng; Zhang, He; Wang, Zhi; Xu, Bingcheng

    2016-01-01

    Altered precipitation regimes significantly affect ecosystem structure and function in arid and semi-arid regions. In order to investigate effects of precipitation changes on natural grassland community in the semi-arid Loess Plateau, the current research examined eco-physiological characteristics of two co-dominant species (i.e., Bothriochloa ischaemum and Lespedeza davurica) and community composition following two watering instances (i.e., precipitation pulses, July and August, 2011, respectively) in a natural grassland community. Results showed that the photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration rapidly increased on the first to third day following watering in both species, and both months. Under watering treatments, the maximum net photosynthetic rates appeared on the second to third day after watering, which increased 30–80% in B. ischaemum and 40–50% in L. davurica compared with non-watering treatments, respectively. Leaf water use efficiency kept stable or initially decreased in both species under watering treatments. Watering in July produced more promoting effects on grass photosynthesis than in August, particularly in B. ischaemum. Community above-ground biomass at the end of the growing season increased after watering, although no significant changes in species diversity were observed. Our results indicated that timing and magnitude of watering could significantly affect plant eco-physiological processes, and there were species-specific responses in B. ischaemum and L. davurica. Pulsed watering increased community productivity, while did not significantly alter community composition after one growing season. The outcomes of this study highlight eco-physiological traits in dominant species may playing important roles in reshaping community composition under altered precipitation regimes. PMID:27242864

  4. Tree Species Linked to Large Differences in Ecosystem Carbon Distribution in the Boreal Forest of Alaska

    NASA Astrophysics Data System (ADS)

    Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A. G.; Genet, H.; McGuire, A. D.

    2014-12-01

    In the boreal forest of Alaska, increased fire severity associated with climate change is altering plant-soil-microbial feedbacks and ecosystem carbon (C) dynamics. The boreal landscape has historically been dominated by black spruce (Picea mariana), a tree species associated with slow C turnover and large soil organic matter (SOM) accumulation. Historically, low severity fires have led to black spruce regeneration post-fire, thereby maintaining slow C cycling rates and large SOM pools. In recent decades however, an increase in high severity fires has led to greater consumption of the soil organic layer (SOL) during fire and subsequent establishment of deciduous tree species in areas previously dominated by black spruce. This shift to a more deciduous dominated landscape has many implications for ecosystem structure and function, as well as feedbacks to global C cycling. To improve our understanding of how boreal tree species affect C cycling, we quantified above- and belowground C stocks and fluxes in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1958 fire near Fairbanks, Alaska. Although total ecosystem C pools (aboveground live tree biomass + dead wood + SOL + top 10 cm of mineral soil) were similar for the two stand types, the distribution of C among pools was markedly different. In black spruce, 78% of measured C was found in soil pools, primarily in the SOL, where spruce contained twice the C stored in paper birch (4.8 ± 0.3 vs. 2.4 ± 0.1 kg C m-2). In contrast, aboveground biomass dominated ecosystem C pools in birch forest (6.0 ± 0.3 vs. 2.5 ± 0.2 kg C m-2 in birch and spruce, respectively). Our findings suggest that tree species exert a strong influence over plant-soil-microbial feedbacks and may have long-term effects on ecosystem C sequestration and storage that feedback to the climate system.

  5. Could beaked whales get the bends? Effect of diving behaviour and physiology on modelled gas exchange for three species: Ziphius cavirostris, Mesoplodon densirostris and Hyperoodon ampullatus.

    PubMed

    Hooker, Sascha K; Baird, Robin W; Fahlman, Andreas

    2009-07-31

    A mathematical model, based on current knowledge of gas exchange and physiology of marine mammals, was used to predict blood and tissue tension N2 (P(N2)) using field data from three beaked whale species: northern bottlenose whales, Cuvier's beaked whales, and Blainville's beaked whales. The objective was to determine if physiology (body mass, diving lung volume, dive response) or dive behaviour (dive depth and duration, changes in ascent rate, diel behaviour) would lead to differences in P(N2) levels and thereby decompression sickness (DCS) risk between species. Diving lung volume and extent of the dive response had a large effect on end-dive P(N2). The dive profile had a larger influence on end-dive P(N2) than body mass differences between species. Despite diel changes in dive behaviour, P(N2) levels showed no consistent trend. Model output suggested that all three species live with tissue P(N2) levels that would cause a significant proportion of DCS cases in terrestrial mammals. Cuvier's beaked whale diving behaviour appears to put them at higher risk than the other species, which may explain their prevalence in strandings after the use of mid-frequency sonar. PMID:19427415

  6. Linking species richness curves from non-contiguous sampling to contiguous-nested SAR: An empirical study

    NASA Astrophysics Data System (ADS)

    Lazarina, Maria; Kallimanis, Athanasios S.; Pantis, John D.; Sgardelis, Stefanos P.

    2014-11-01

    The species-area relationship (SAR) is one of the few generalizations in ecology. However, many different relationships are denoted as SARs. Here, we empirically evaluated the differences between SARs derived from nested-contiguous and non-contiguous sampling designs, using plants, birds and butterflies datasets from Great Britain, Greece, Massachusetts, New York and San Diego. The shape of SAR depends on the sampling scheme, but there is little empirical documentation on the magnitude of the deviation between different types of SARs and the factors affecting it. We implemented a strictly nested sampling design to construct nested-contiguous SAR (SACR), and systematic nested but non-contiguous, and random designs to construct non-contiguous species richness curves (SASRs for systematic and SACs for random designs) per dataset. The SACR lay below any SASR and most of the SACs. The deviation between them was related to the exponent f of the power law relationship between sampled area and extent. The lower the exponent f, the higher was the deviation between the curves. We linked SACR to SASR and SAC through the concept of "effective" area (Ae), i.e. the nested-contiguous area containing equal number of species with the accumulated sampled area (AS) of a non-contiguous sampling. The relationship between effective and sampled area was modeled as log(Ae) = klog(AS). A Generalized Linear Model was used to estimate the values of k from sampling design and dataset properties. The parameter k increased with the average distance between samples and with beta diversity, while k decreased with f. For both systematic and random sampling, the model performed well in predicting effective area in both the training set and in the test set which was totally independent from the training one. Through effective area, we can link different types of species richness curves based on sampling design properties, sampling effort, spatial scale and beta diversity patterns.

  7. Leaf hydraulic vulnerability to drought is linked to site water availability across a broad range of species and climates

    PubMed Central

    Blackman, Chris J.; Gleason, Sean M.; Chang, Yvonne; Cook, Alicia M.; Laws, Claire; Westoby, Mark

    2014-01-01

    Background and Aims Vulnerability of the leaf hydraulic pathway to water-stress-induced dysfunction is a key component of drought tolerance in plants and may be important in defining species' climatic range. However, the generality of the association between leaf hydraulic vulnerability and climate across species and sites remains to be tested. Methods Leaf hydraulic vulnerability to drought (P50leaf, the water potential inducing 50 % loss in hydraulic function) was measured in a diverse group of 92 woody, mostly evergreen angiosperms from sites across a wide range of habitats. These new data together with some previously published were tested against key climate indices related to water availability. Differences in within-site variability in P50leaf between sites were also examined. Key Results Values of hydraulic vulnerability to drought in leaves decreased strongly (i.e. became more negative) with decreasing annual rainfall and increasing aridity across sites. The standard deviation in P50leaf values recorded within each site was positively correlated with increasing aridity. P50leaf was also a good indicator of the climatic envelope across each species' distributional range as well as their dry-end distributional limits within Australia, although this relationship was not consistently detectable within sites. Conclusions The findings indicate that species sorting processes have influenced distributional patterns of P50leaf across the rainfall spectrum, but alternative strategies for dealing with water deficit exist within sites. The strong link to aridity suggests leaf hydraulic vulnerability may influence plant distributions under future climates. PMID:25006181

  8. Prevalence and Dynamics of Ribosomal DNA Micro-heterogeneity Are Linked to Population History in Two Contrasting Yeast Species.

    PubMed

    James, Stephen A; West, Claire; Davey, Robert P; Dicks, Jo; Roberts, Ian N

    2016-01-01

    Despite the considerable number and taxonomic breadth of past and current genome sequencing projects, many of which necessarily encompass the ribosomal DNA, detailed information on the prevalence and evolutionary significance of sequence variation in this ubiquitous genomic region are severely lacking. Here, we attempt to address this issue in two closely related yet contrasting yeast species, the baker's yeast Saccharomyces cerevisiae and the wild yeast Saccharomyces paradoxus. By drawing on existing datasets from the Saccharomyces Genome Resequencing Project, we identify a rich seam of ribosomal DNA sequence variation, characterising 1,068 and 970 polymorphisms in 34 S. cerevisiae and 26 S. paradoxus strains respectively. We discover the two species sets exhibit distinct mutational profiles. Furthermore, we show for the first time that unresolved rDNA sequence variation resulting from imperfect concerted evolution of the ribosomal DNA region follows a U-shaped allele frequency distribution in each species, similar to loci that evolve under non-concerted mechanisms but arising through rather different evolutionary processes. Finally, we link differences between the shapes of these allele frequency distributions to the two species' contrasting population histories. PMID:27345953

  9. A comparative study of physiological and morphological seedling traits associated with shade tolerance in introduced red oak (Quercus rubra) and native hardwood tree species in southwestern Germany.

    PubMed

    Kuehne, Christian; Nosko, Peter; Horwath, Tobias; Bauhus, Jürgen

    2014-02-01

    Northern red oak (Quercus rubra L.), a moderately shade-tolerant tree species, is failing to regenerate throughout its native North American range, while successful recruitment in Central Europe has been observed since its introduction. To examine whether comparative photosynthetic performance could explain the regeneration success of this non-native species in Central Europe, we compared the physiological and morphological seedling traits of red oak with three co-occurring tree species under three canopy types in southwestern Germany. Native species included a moderately shade-tolerant native oak (Quercus robur L.) and two shade-tolerant species (Acer pseudoplatanus L. and Carpinus betulus L.). The photosynthetic traits of non-native red oak seedlings were similar to those reported for this species in the native range, where shade-tolerant competitors readily outperform red oak under low light conditions. However, compared with native shade-tolerant species in Europe, red oak seedlings photosynthesized efficiently, especially under closed canopies and in small canopy gaps, exhibiting high photosynthetic capacity, low leaf dark respiration and leaf-level light compensation points that were similar to the more shade-tolerant species. The superior net carbon gain of red oak seedlings at low and moderate light levels was likely facilitated by high leaf areas and reflected by seedling dry masses that were greater than the observed native European species. A competitive advantage for red oak was not evident because relative height growth was inferior to seedlings of co-occurring species. In North America, the inability of seedlings to compete with shade-tolerant tree species in deeply shaded understories is central to the problem of poor oak recruitment. Our study suggests that the ability of non-native red oak to perform equally well to native shade-tolerant species under a variety of light conditions could contribute to the consistent success of red oak regeneration

  10. Link between capacity for current production and syntrophic growth in Geobacter species

    PubMed Central

    Rotaru, Amelia-Elena; Woodard, Trevor L.; Nevin, Kelly P.; Lovley, Derek R.

    2015-01-01

    Electrodes are unnatural electron acceptors, and it is yet unknown how some Geobacter species evolved to use electrodes as terminal electron acceptors. Analysis of different Geobacter species revealed that they varied in their capacity for current production. Geobacter metallireducens and G. hydrogenophilus generated high current densities (ca. 0.2 mA/cm2), comparable to G. sulfurreducens. G. bremensis, G. chapellei, G. humireducens, and G. uraniireducens, produced much lower currents (ca. 0.05 mA/cm2) and G. bemidjiensis was previously found to not produce current. There was no correspondence between the effectiveness of current generation and Fe(III) oxide reduction rates. Some high-current-density strains (G. metallireducens and G. hydrogenophilus) reduced Fe(III)-oxides as fast as some low-current-density strains (G. bremensis, G. humireducens, and G. uraniireducens) whereas other low-current-density strains (G. bemidjiensis and G. chapellei) reduced Fe(III) oxide as slowly as G. sulfurreducens, a high-current-density strain. However, there was a correspondence between the ability to produce higher currents and the ability to grow syntrophically. G. hydrogenophilus was found to grow in co-culture with Methanosarcina barkeri, which is capable of direct interspecies electron transfer (DIET), but not with Methanospirillum hungatei capable only of H2 or formate transfer. Conductive granular activated carbon (GAC) stimulated metabolism of the G. hydrogenophilus – M. barkeri co-culture, consistent with electron exchange via DIET. These findings, coupled with the previous finding that G. metallireducens and G. sulfurreducens are also capable of DIET, suggest that evolution to optimize DIET has fortuitously conferred the capability for high-density current production to some Geobacter species. PMID:26284037

  11. Linking density, productivity and trends of an endangered species: The Bonelli's eagle in Spain

    NASA Astrophysics Data System (ADS)

    Carrascal, Luis M.; Seoane, Javier

    2009-05-01

    Whether regional population density is a good indicator of environmental quality according to demographic variables such as breeding success or short-term population trends is controversial. In this paper we analyze the interrelationships among regional population density, breeding success and recent population trends of an endangered species, Bonelli's eagle in the Iberian Peninsula. We also analyze the different influence of geographical, climatic, landscape structure and human impact variables on regional variation in those demographic variables. Breeding success was higher and population decrease was lower in those areas where the population density of Bonelli's eagle was greater. Breeding success, density and recent population trends of Bonelli's eagle were tightly related, increasing from northern to southern Iberian Peninsula (with highest figures at intermediate latitudes), and as sun radiation increased, and altitude decreased. Breeding success and population density were significantly lower in the periphery of the distribution range than in core areas in the Iberian Peninsula. Population trends between 2000 and 2005 were also more negative (decreasing) in the periphery. Overall, these results suggest that population density in this endangered species of large home-range is a good indicator of environmental quality and reproductive output, and that peripheral populations occupy low-suitability areas with lower breeding success, where negative short-term population trends are more likely.

  12. A Complex Genetic Basis to X-Linked Hybrid Male Sterility Between Two Species of House Mice

    PubMed Central

    Good, Jeffrey M.; Dean, Matthew D.; Nachman, Michael W.

    2008-01-01

    The X chromosome plays a central role in the evolution of reproductive isolation, but few studies have examined the genetic basis of X-linked incompatibilities during the early stages of speciation. We report the results of a large experiment focused on the reciprocal introgression of the X chromosome between two species of house mice, Mus musculus and M. domesticus. Introgression of the M. musculus X chromosome into a wild-derived M. domesticus genetic background produced male-limited sterility, qualitatively consistent with previous experiments using classic inbred strains to represent M. domesticus. The genetic basis of sterility involved a minimum of four X-linked factors. The phenotypic effects of major sterility QTL were largely additive and resulted in complete sterility when combined. No sterility factors were uncovered on the M. domesticus X chromosome. Overall, these results revealed a complex and asymmetric genetic basis to X-linked hybrid male sterility during the early stages of speciation in mice. Combined with data from previous studies, we identify one relatively narrow interval on the M. musculus X chromosome involved in hybrid male sterility. Only a handful of spermatogenic genes are within this region, including one of the most rapidly evolving genes on the mouse X chromosome. PMID:18689897

  13. Measures of physiological stress: a transparent or opaque window into the status, management and conservation of species?

    PubMed Central

    Dantzer, Ben; Fletcher, Quinn E.; Boonstra, Rudy; Sheriff, Michael J.

    2014-01-01

    Conservation physiology proposes that measures of physiological stress (glucocorticoid levels) can be used to assess the status and future fate of natural populations. Increases in glucocorticoids may reflect a more challenging environment, suggesting that the influence of human activities on free-living animals could be quantified by measuring glucocorticoids. Biomedical studies suggest that chronic increases in glucocorticoids can have detrimental effects on survival and reproduction, which could influence the viability of populations. Here, we discuss the use of measurements of glucocorticoids in conservation physiology. We first provide an overview of the different methods to quantify glucocorticoids and their utility in conservation physiology. We then discuss five questions we think are essential for conservation physiologists to address. We highlight how intrinsic (e.g. sex, reproductive status, age, recent experiences) and ecological factors (e.g. predation, food availability, snowfall) can, by themselves or through their interactions with anthropogenic disturbances, affect the physiological stress response and mask any general patterns about the effects of anthropogenic disturbances on glucocorticoids. Using a meta-analysis, we show that anthropogenic disturbances are consistently associated with increased glucocorticoids regardless of the type of human disturbance. We also show that males may be more sensitive to anthropogenic disturbances than females and that faecal glucocorticoids, but not baseline plasma glucocorticoids, consistently increase in response to anthropogenic disturbances. Finally, we discuss how increases in glucocorticoids in free-living animals can sometimes enhance survival and reproduction. Unfortunately, our literature analysis indicates that this observation has not yet gained traction, and very few studies have shown that increases in glucocorticoid levels resulting from anthropogenic disturbances decrease survival or reproduction

  14. Linking limitation to species composition: importance of inter- and intra-specific variation in grazing resistance.

    PubMed

    Darcy-Hall, Tara L; Hall, Spencer R

    2008-04-01

    Short-term responses of producers highlight that key nutrients (e.g., N, P)-or combinations of these nutrients-limit primary production in aquatic and terrestrial ecosystems. These discoveries continue to provide highly valuable insights, but it remains important to ask whether nutrients always predominantly limit producers despite wide variation in nutrient supply and herbivory among systems. After all, predictions from simple food chain models (derived here) readily predict that limitation by grazers can exceed that by nutrients, given sufficient enrichment. However, shifts in composition of producers and/or increasing dominance of invulnerable stages of a producer can, in theory, reduce grazer limitation and retain primacy of nutrient limitation along nutrient supply gradients. We observed both mechanisms (inter- and intra-species variation in vulnerability to herbivory) working in a two-part mesocosm experiment. We incubated diverse benthic algal assemblages for several months either in the presence or absence of benthic macro-grazers in mesocosms that spread a broad range of nutrient supply. We then conducted short-term assays of nutrient and grazer limitation on these communities. In the "historically grazed" assemblages, we found shifts from more edible, better competitors to more resistant producers over enrichment gradients (as anticipated by the food web model built with a tradeoff in resistance vs. competitive abilities). However, contrary to our expectations, "historically ungrazed" assemblages became dominated by producers with vulnerable juvenile forms but inedible adult forms (long filaments). Consequently, we observed higher resource limitation rather than grazer limitation over this nutrient supply gradient in both "historically grazed" (expected) and "historically ungrazed" (not initially expected). Thus, via multiple, general mechanisms involving resistance to grazing (changes in species composition or variation in stage-structured vulnerability

  15. ALS-linked misfolded SOD1 species have divergent impacts on mitochondria.

    PubMed

    Pickles, Sarah; Semmler, Sabrina; Broom, Helen R; Destroismaisons, Laurie; Legroux, Laurine; Arbour, Nathalie; Meiering, Elizabeth; Cashman, Neil R; Vande Velde, Christine

    2016-01-01

    Approximately 20 % of familial Amyotrophic Lateral Sclerosis (ALS) is caused by mutations in superoxide dismutase (SOD1), which leads to misfolding of the SOD1 protein, resulting in a toxic gain of function. Several conformation-restricted antibodies have been generated that specifically recognize misfolded SOD1 protein, and have been used as therapeutics in pre-clinical models. Misfolded SOD1 selectively associates with spinal cord mitochondria in SOD1 rodent models. Using the SOD1(G93A) rat model, we find that SOD1 conformational specific antibodies AMF7-63 and DSE2-3H1 labeled a fibrillar network concentrated in the anterior horn; while A5C3, B8H10, C4F6 and D3H5 labeled motor neurons as well as puncta in the neuropil. There is a time-dependent accumulation of misfolded SOD1 at the surface of spinal cord mitochondria with AMF7-63-labeled mitochondria having increased volume in contrast to a mitochondrial subset labeled with B8H10. In spinal cord homogenates and isolated mitochondria, AMF7-63, DSE2-3H1 and B8H10 detect misfolded SOD1 aggregates. SOD1 that lacks its metal cofactors has an increased affinity for naïve mitochondria and misfolded SOD1 antibodies B8H10 and DSE2-3H1 readily detect demetalated mutant and wild-type SOD1. Together, these data suggest that multiple non-native species of misfolded SOD1 may exist, some of which are associated with mitochondrial damage. Conformational antibodies are invaluable tools to identify and characterize the variation in misfolded SOD1 species with regards to biochemical characteristics and toxicity. This information is highly relevant to the further development of these reagents as therapeutics. PMID:27121871

  16. Skeletal Muscle Pathology in X-Linked Myotubular Myopathy: Review With Cross-Species Comparisons

    PubMed Central

    Lawlor, Michael W.; Beggs, Alan H.; Buj-Bello, Ana; Childers, Martin K.; Dowling, James J.; James, Emma S.; Meng, Hui; Moore, Steven A.; Prasad, Suyash; Schoser, Benedikt; Sewry, Caroline A.

    2016-01-01

    X-linked myotubular myopathy (XLMTM) is a devastating, rare, congenital myopathy caused by mutations in the MTM1 gene, resulting in a lack of or dysfunction of the enzyme myotubularin. This leads to severe perinatal weakness and distinctive muscle pathology. It was originally thought that XLMTM was related to developmental arrest in myotube maturation; however, the generation and characterization of several animal models have significantly improved our understanding of clinical and pathological aspects of this disorder. Myotubularin is now known to participate in numerous cellular processes including endosomal trafficking, excitation-contraction coupling, cytoskeletal organization, neuromuscular junction structure, autophagy, and satellite cell proliferation and survival. The available vertebrate models of XLMTM, which vary in severity from complete absence to reduced functional levels of myotubularin, recapitulate features of the human disease to a variable extent. Understanding how pathological endpoints in animals with XLMTM translate to human patients will be essential to interpret preclinical treatment trials and translate therapies into human clinical studies. This review summarizes the published animal models of XLMTM, including those of zebrafish, mice, and dogs, with a focus on their pathological features as compared to those seen in human XLMTM patients. PMID:26823526

  17. Prevalence and Dynamics of Ribosomal DNA Micro-heterogeneity Are Linked to Population History in Two Contrasting Yeast Species

    PubMed Central

    James, Stephen A.; West, Claire; Davey, Robert P.; Dicks, Jo; Roberts, Ian N.

    2016-01-01

    Despite the considerable number and taxonomic breadth of past and current genome sequencing projects, many of which necessarily encompass the ribosomal DNA, detailed information on the prevalence and evolutionary significance of sequence variation in this ubiquitous genomic region are severely lacking. Here, we attempt to address this issue in two closely related yet contrasting yeast species, the baker’s yeast Saccharomyces cerevisiae and the wild yeast Saccharomyces paradoxus. By drawing on existing datasets from the Saccharomyces Genome Resequencing Project, we identify a rich seam of ribosomal DNA sequence variation, characterising 1,068 and 970 polymorphisms in 34 S. cerevisiae and 26 S. paradoxus strains respectively. We discover the two species sets exhibit distinct mutational profiles. Furthermore, we show for the first time that unresolved rDNA sequence variation resulting from imperfect concerted evolution of the ribosomal DNA region follows a U-shaped allele frequency distribution in each species, similar to loci that evolve under non-concerted mechanisms but arising through rather different evolutionary processes. Finally, we link differences between the shapes of these allele frequency distributions to the two species’ contrasting population histories. PMID:27345953

  18. Physiological response to elevated temperature and pCO2 varies across four Pacific coral species: Understanding the unique host+symbiont response.

    PubMed

    Hoadley, Kenneth D; Pettay, D Tye; Grottoli, Andréa G; Cai, Wei-Jun; Melman, Todd F; Schoepf, Verena; Hu, Xinping; Li, Qian; Xu, Hui; Wang, Yongchen; Matsui, Yohei; Baumann, Justin H; Warner, Mark E

    2015-01-01

    The physiological response to individual and combined stressors of elevated temperature and pCO2 were measured over a 24-day period in four Pacific corals and their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15, and Turbinaria reniformis/Symbiodinium trenchii). Multivariate analyses indicated that elevated temperature played a greater role in altering physiological response, with the greatest degree of change occurring within M. monasteriata and T. reniformis. Algal cellular volume, protein, and lipid content all increased for M. monasteriata. Likewise, S. trenchii volume and protein content in T. reniformis also increased with temperature. Despite decreases in maximal photochemical efficiency, few changes in biochemical composition (i.e. lipids, proteins, and carbohydrates) or cellular volume occurred at high temperature in the two thermally sensitive symbionts C21a and C1c-d-t. Intracellular carbonic anhydrase transcript abundance increased with temperature in A. millepora but not in P. damicornis, possibly reflecting differences in host mitigated carbon supply during thermal stress. Importantly, our results show that the host and symbiont response to climate change differs considerably across species and that greater physiological plasticity in response to elevated temperature may be an important strategy distinguishing thermally tolerant vs. thermally sensitive species. PMID:26670946

  19. Physiological response to elevated temperature and pCO2 varies across four Pacific coral species: Understanding the unique host+symbiont response

    PubMed Central

    Hoadley, Kenneth D.; Pettay, D. Tye; Grottoli, Andréa G.; Cai, Wei-Jun; Melman, Todd F.; Schoepf, Verena; Hu, Xinping; Li, Qian; Xu, Hui; Wang, Yongchen; Matsui, Yohei; Baumann, Justin H.; Warner, Mark E.

    2015-01-01

    The physiological response to individual and combined stressors of elevated temperature and pCO2 were measured over a 24-day period in four Pacific corals and their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15, and Turbinaria reniformis/Symbiodinium trenchii). Multivariate analyses indicated that elevated temperature played a greater role in altering physiological response, with the greatest degree of change occurring within M. monasteriata and T. reniformis. Algal cellular volume, protein, and lipid content all increased for M. monasteriata. Likewise, S. trenchii volume and protein content in T. reniformis also increased with temperature. Despite decreases in maximal photochemical efficiency, few changes in biochemical composition (i.e. lipids, proteins, and carbohydrates) or cellular volume occurred at high temperature in the two thermally sensitive symbionts C21a and C1c-d-t. Intracellular carbonic anhydrase transcript abundance increased with temperature in A. millepora but not in P. damicornis, possibly reflecting differences in host mitigated carbon supply during thermal stress. Importantly, our results show that the host and symbiont response to climate change differs considerably across species and that greater physiological plasticity in response to elevated temperature may be an important strategy distinguishing thermally tolerant vs. thermally sensitive species. PMID:26670946

  20. Physiological response to elevated temperature and pCO2 varies across four Pacific coral species: Understanding the unique host+symbiont response

    NASA Astrophysics Data System (ADS)

    Hoadley, Kenneth D.; Pettay, D. Tye; Grottoli, Andréa G.; Cai, Wei-Jun; Melman, Todd F.; Schoepf, Verena; Hu, Xinping; Li, Qian; Xu, Hui; Wang, Yongchen; Matsui, Yohei; Baumann, Justin H.; Warner, Mark E.

    2015-12-01

    The physiological response to individual and combined stressors of elevated temperature and pCO2 were measured over a 24-day period in four Pacific corals and their respective symbionts (Acropora millepora/Symbiodinium C21a, Pocillopora damicornis/Symbiodinium C1c-d-t, Montipora monasteriata/Symbiodinium C15, and Turbinaria reniformis/Symbiodinium trenchii). Multivariate analyses indicated that elevated temperature played a greater role in altering physiological response, with the greatest degree of change occurring within M. monasteriata and T. reniformis. Algal cellular volume, protein, and lipid content all increased for M. monasteriata. Likewise, S. trenchii volume and protein content in T. reniformis also increased with temperature. Despite decreases in maximal photochemical efficiency, few changes in biochemical composition (i.e. lipids, proteins, and carbohydrates) or cellular volume occurred at high temperature in the two thermally sensitive symbionts C21a and C1c-d-t. Intracellular carbonic anhydrase transcript abundance increased with temperature in A. millepora but not in P. damicornis, possibly reflecting differences in host mitigated carbon supply during thermal stress. Importantly, our results show that the host and symbiont response to climate change differs considerably across species and that greater physiological plasticity in response to elevated temperature may be an important strategy distinguishing thermally tolerant vs. thermally sensitive species.

  1. Plant Survival and Mortality during Drought Can be Mediated by Co-occurring Species' Physiological and Morphological Traits: Results from a Model

    NASA Astrophysics Data System (ADS)

    Tai, X.; Mackay, D. S.

    2015-12-01

    Interactions among co-occurring species are mediated by plant physiology, morphology and environment. Without proper mechanisms to account for these factors, it remains difficult to predict plant mortality/survival under changing climate. A plant ecophysiological model, TREES, was extended to incorporate co-occurring species' belowground interaction for water. We used it to examine the interaction between two commonly co-occurring species during drought experiment, pine (Pinus edulis) and juniper (Juniperus monosperma), with contrasting physiological traits (vulnerability to cavitation and leaf water potential regulation). TREES was parameterized and validated using field-measured plant physiological traits. The root architecture (depth, profile, and root area to leaf area ratio) of juniper was adjusted to see how root morphology could affect the survival/mortality of its neighboring pine under both ambient and drought conditions. Drought suppressed plant water and carbon uptake, as well increased the average percentage loss of conductivity (PLC). Pine had 59% reduction in water uptake, 48% reduction in carbon uptake, and 38% increase in PLC, while juniper had 56% reduction in water uptake, 50% reduction in carbon and 29% increase in PLC, suggesting different vulnerability to drought as mediated by plant physiological traits. Variations in juniper root architecture further mediated drought stress on pine, from negative to positive. Different juniper root architecture caused variations in response of pine over drought (water uptake reduction ranged 0% ~63%, carbon uptake reduction ranged 0% ~ 70%, and PLC increase ranged 2% ~ 91%). Deeper or more uniformly distributed roots of juniper could effectively mitigate stress experienced by pine. In addition, the total water and carbon uptake tended to increase as the ratio of root area to leaf area increased while PLC showed non-monotonic response, suggesting the potential trade-off between maximizing resource uptake and

  2. Reactive Oxygen Species, Endoplasmic Reticulum Stress and Mitochondrial Dysfunction: The Link with Cardiac Arrhythmogenesis

    PubMed Central

    Tse, Gary; Yan, Bryan P.; Chan, Yin W. F.; Tian, Xiao Yu; Huang, Yu

    2016-01-01

    Background: Cardiac arrhythmias represent a significant problem globally, leading to cerebrovascular accidents, myocardial infarction, and sudden cardiac death. There is increasing evidence to suggest that increased oxidative stress from reactive oxygen species (ROS), which is elevated in conditions such as diabetes and hypertension, can lead to arrhythmogenesis. Method: A literature review was undertaken to screen for articles that investigated the effects of ROS on cardiac ion channel function, remodeling and arrhythmogenesis. Results: Prolonged endoplasmic reticulum stress is observed in heart failure, leading to increased production of ROS. Mitochondrial ROS, which is elevated in diabetes and hypertension, can stimulate its own production in a positive feedback loop, termed ROS-induced ROS release. Together with activation of mitochondrial inner membrane anion channels, it leads to mitochondrial depolarization. Abnormal function of these organelles can then activate downstream signaling pathways, ultimately culminating in altered function or expression of cardiac ion channels responsible for generating the cardiac action potential (AP). Vascular and cardiac endothelial cells become dysfunctional, leading to altered paracrine signaling to influence the electrophysiology of adjacent cardiomyocytes. All of these changes can in turn produce abnormalities in AP repolarization or conduction, thereby increasing likelihood of triggered activity and reentry. Conclusion: ROS plays a significant role in producing arrhythmic substrate. Therapeutic strategies targeting upstream events include production of a strong reducing environment or the use of pharmacological agents that target organelle-specific proteins and ion channels. These may relieve oxidative stress and in turn prevent arrhythmic complications in patients with diabetes, hypertension, and heart failure. PMID:27536244

  3. Climate missing links: Aqueous greenhouse species in clouds, fogs and aerosols

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Cunningham, M.M.

    1991-11-01

    Recently, there has been considerable interest regarding possible greenhouse effects due to combustion and energy-related pollution. This concern has been due to the release and secondary production of greenhouse gases such as carbon dioxide, freons, methane, nitrous oxide, and ozone. These gases can absorb infrared radiation as it comes back from the heated ground and therefore effectively trap the infrared radiation in the troposphere, leading to climatic change. Beyond these gases, clouds, aerosols, and fogs may also play important roles in affecting, the radiation balance by scattering incoming radiation. This work describes the measurement of water soluble infrared absorbers that are known to be derived from pollution. Polluted precipitation is likely to be an important contributor to radiation balance that is currently being neglected. Pollutants characterized include sulfate, nitrate, formate, acetate, oxalate, phenol, p-nitrophenol, ammonium, carbonate, bicarbonate, formaldehyde (dihydroxy methane), methanol, and ethanol. Band positions and band strengths have been determined. These species show measurable infrared absorption bands in the atmospheric window regions (i.e., 900--1600 cm{sup {minus}1}). These data are discussed with regard to the reported discrepancies in the radiatively important water infrared absorption region commonly referred to as the ``foreign broadened continuum.``

  4. Linking Self-Incompatibility, Dichogamy, and Flowering Synchrony in Two Euphorbia Species: Alternative Mechanisms for Avoiding Self-Fertilization?

    PubMed Central

    Narbona, Eduardo; Ortiz, Pedro L.; Arista, Montserrat

    2011-01-01

    Background Plant species have several mechanisms to avoid selfing such as dichogamy or a self-incompatibility response. Dichogamy in a single flower may reduce autogamy but, to avoid geitonogamy, plants must show flowering synchronization among all their flowers (i.e. synchronous dichogamy). It is hypothesized that one species would not simultaneously show synchronous dichogamy and self-incompatibility because they are redundant mechanisms to reduce selfing; however, this has not been accurately assessed. Methodology/Principal Findings This expectation was tested over two years in two natural populations of the closely related Mediterranean spurges Euphorbia boetica and E. nicaeensis, which completely avoid autogamy by protogyny at the cyathia level. Both spurges showed a high population synchrony (Z<79), and their inflorescences flower synchronously. In E. nicaeensis, there was no overlap among the cyathia in anthesis of successive inflorescence levels and the overlap between sexual phases of cyathia of the same inflorescence level was uncommon (4–16%). In contrast, E. boetica showed a high overlap among consecutive inflorescence levels (74–93%) and between sexual phases of cyathia of the same inflorescence level (48–80%). The flowering pattern of both spurges was consistent in the two populations and over the two successive years. A hand-pollination experiment demonstrated that E. nicaeensis was strictly self-compatible whereas E. boetica was partially self-incompatible. Conclusions/Significance We propose that the complex pattern of synchronized protogyny in E. nicaeensis prevents geitonogamous crosses and, consequently, avoids selfing and inbreeding depression. In E. boetica, a high probability of geitonogamous crosses may occur but, alternatively, this plant escapes selfing through a self-incompatibility response. We posit that synchronous dichogamy and physiological self-incompatibility do not co-occur in the same species because each process is

  5. Nucleotide receptor signaling in murine macrophages is linked to reactive oxygen species generation.

    PubMed

    Pfeiffer, Zachary A; Guerra, Alma N; Hill, Lindsay M; Gavala, Monica L; Prabhu, Usha; Aga, Mini; Hall, David J; Bertics, Paul J

    2007-05-15

    Macrophage activation is critical in the innate immune response and can be regulated by the nucleotide receptor P2X7. In this regard, P2X7 signaling is not well understood but has been implicated in controlling reactive oxygen species (ROS) generation by various leukocytes. Although ROS can contribute to microbial killing, the role of ROS in nucleotide-mediated cell signaling is unclear. In this study, we report that the P2X7 agonists ATP and 3'-O-(4-benzoyl) benzoic ATP (BzATP) stimulate ROS production by RAW 264.7 murine macrophages. These effects are potentiated in lipopolysaccharide-primed cells, demonstrating an important interaction between extracellular nucleotides and microbial products in ROS generation. In terms of nucleotide receptor specificity, RAW 264.7 macrophages that are deficient in P2X7 are greatly reduced in their capacity to generate ROS in response to BzATP treatment (both with and without LPS priming), thus supporting a role for P2X7 in this process. Because MAP kinase activation is key for nucleotide regulation of macrophage function, we also tested the hypothesis that P2X7-mediated MAP kinase activation is dependent on ROS production. We observed that BzATP stimulates MAP kinase (ERK1/ERK2, p38, and JNK1/JNK2) phosphorylation and that the antioxidants N-acetylcysteine and ascorbic acid strongly attenuate BzATP-mediated JNK1/JNK2 and p38 phosphorylation but only slightly reduce BzATP-induced ERK1/ERK2 phosphorylation. These studies reveal that P2X7 can contribute to macrophage ROS production, that this effect is potentiated upon lipopolysaccharide exposure, and that ROS are important participants in the extracellular nucleotide-mediated activation of several MAP kinase systems. PMID:17448897

  6. Reactive Oxygen Species Generation Linked to Sources of Atmospheric Particulate Matter and Cardiorespiratory Effects.

    PubMed

    Bates, Josephine T; Weber, Rodney J; Abrams, Joseph; Verma, Vishal; Fang, Ting; Klein, Mitchel; Strickland, Matthew J; Sarnat, Stefanie Ebelt; Chang, Howard H; Mulholland, James A; Tolbert, Paige E; Russell, Armistead G

    2015-11-17

    Exposure to atmospheric fine particulate matter (PM2.5) is associated with cardiorespiratory morbidity and mortality, but the mechanisms are not well understood. We assess the hypothesis that PM2.5 induces oxidative stress in the body via catalytic generation of reactive oxygen species (ROS). A dithiothreitol (DTT) assay was used to measure the ROS-generation potential of water-soluble PM2.5. Source apportionment on ambient (Atlanta, GA) PM2.5 was performed using the chemical mass balance method with ensemble-averaged source impact profiles. Linear regression analysis was used to relate PM2.5 emission sources to ROS-generation potential and to estimate historical levels of DTT activity for use in an epidemiologic analysis for the period of 1998-2009. Light-duty gasoline vehicles (LDGV) exhibited the highest intrinsic DTT activity, followed by biomass burning (BURN) and heavy-duty diesel vehicles (HDDV) (0.11 ± 0.02, 0.069 ± 0.02, and 0.052 ± 0.01 nmol min(-1) μg(-1)source, respectively). BURN contributed the largest fraction to total DTT activity over the study period, followed by LDGV and HDDV (45, 20, and 14%, respectively). DTT activity was more strongly associated with emergency department visits for asthma/wheezing and congestive heart failure than PM2.5. This work provides further epidemiologic evidence of a biologically plausible mechanism, that of oxidative stress, for associations of adverse health outcomes with PM2.5 mass and supports continued assessment of the utility of the DTT activity assay as a measure of ROS-generating potential of particles. PMID:26457347

  7. A comparative analysis of transcriptomic, biochemical, and physiological responses to elevated ozone identifies species-specific mechanisms of resilience in legume crops

    PubMed Central

    Yendrek, Craig R.; Koester, Robert P.

    2015-01-01

    Current concentrations of tropospheric ozone ([O3]) pollution negatively impact plant metabolism, which can result in decreased crop yields. Interspecific variation in the physiological response of plants to elevated [O3] exists; however, the underlying cellular responses explaining species-specific differences are largely unknown. Here, a physiological screen has been performed on multiple varieties of legume species. Three varieties of garden pea (Pisum sativum L.) were resilient to elevated [O3]. Garden pea showed no change in photosynthetic capacity or leaf longevity when exposed to elevated [O3], in contrast to varieties of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.). Global transcriptomic and targeted biochemical analyses were then done to examine the mechanistic differences in legume responses to elevated [O3]. In all three species, there was an O3-mediated reduction in specific leaf weight and total non-structural carbohydrate content, as well as increased abundance of respiration-related transcripts. Differences specific to garden pea included a pronounced increase in the abundance of GLUTATHIONE REDUCTASE transcript, as well as greater contents of foliar glutathione, apoplastic ascorbate, and sucrose in elevated [O3]. These results suggest that garden pea may have had greater capacity for detoxification, which prevented net losses in CO2 fixation in an elevated [O3] environment. PMID:26324463

  8. A comparative analysis of transcriptomic, biochemical, and physiological responses to elevated ozone identifies species-specific mechanisms of resilience in legume crops.

    PubMed

    Yendrek, Craig R; Koester, Robert P; Ainsworth, Elizabeth A

    2015-12-01

    Current concentrations of tropospheric ozone ([O3]) pollution negatively impact plant metabolism, which can result in decreased crop yields. Interspecific variation in the physiological response of plants to elevated [O3] exists; however, the underlying cellular responses explaining species-specific differences are largely unknown. Here, a physiological screen has been performed on multiple varieties of legume species. Three varieties of garden pea (Pisum sativum L.) were resilient to elevated [O3]. Garden pea showed no change in photosynthetic capacity or leaf longevity when exposed to elevated [O3], in contrast to varieties of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.). Global transcriptomic and targeted biochemical analyses were then done to examine the mechanistic differences in legume responses to elevated [O3]. In all three species, there was an O3-mediated reduction in specific leaf weight and total non-structural carbohydrate content, as well as increased abundance of respiration-related transcripts. Differences specific to garden pea included a pronounced increase in the abundance of GLUTATHIONE REDUCTASE transcript, as well as greater contents of foliar glutathione, apoplastic ascorbate, and sucrose in elevated [O3]. These results suggest that garden pea may have had greater capacity for detoxification, which prevented net losses in CO2 fixation in an elevated [O3] environment. PMID:26324463

  9. Contrasting hypoxia tolerance and adaptation in Malus species is linked to differences in stomatal behavior and photosynthesis.

    PubMed

    Bai, Tuanhui; Li, Cuiying; Li, Chao; Liang, Dong; Ma, Fengwang

    2013-04-01

    We examined the potential differences in tolerance to hypoxia by two species of apple rootstocks. Stomatal behavior and photosynthesis were compared between Malus sieversii and Malus hupehensis. Plants were hydroponically grown for 15 days in normoxic or hypoxic nutrient solutions. Those of M. sieversii showed much greater sensitivity, with exposure to hypoxia resulting in higher leaf concentrations of abscisic acid (ABA) that prompted stomatal closure. Compared with the control plants of that species, stomatal density was greater in both new and mature leaves under stress conditions. In contrast, stomatal density was significantly decreased in leaves from M. hupehensis, while stomatal length was unaffected. Under stress, the net photosynthetic rate, stomatal conductance and chlorophyll contents were markedly reduced in M. sieversii. The relatively hypoxia-tolerant genotype M. hupehensis, however, showed only minor changes in net photosynthesis or chlorophyll content, and only a slight decrease in stomatal conductance due to such treatment. Therefore, we conclude that the more tolerant M. hupehensis utilizes a better protective mechanism for retaining higher photosynthetic capacity than does the hypoxia-sensitive M. sieversii. Moreover, this contrast in tolerance and adaptation to stress is linked to differences in their stomatal behavior, photosynthetic capacity and possibly their patterns of native distribution. PMID:22924708

  10. Are cicadas (Diceroprocta apache) both a "keystone" and a "critical-link" species in lower Colorado River riparian communities?

    USGS Publications Warehouse

    Andersen, Douglas C.

    1994-01-01

    Apache cicada (Homoptera: Cicadidae: Diceroprocta apache Davis) densities were estimated to be 10 individuals/m2 within a closed-canopy stand of Fremont cottonwood (Populus fremontii) and Goodding willow (Salix gooddingii) in a revegetated site adjacent to the Colorado River near Parker, Arizona. Coupled with data drawn from the literature, I estimate that up to 1.3 cm (13 1/m2) of water may be added to the upper soil layers annually through the feeding activities of cicada nymphs. This is equivalent to 12% of the annual precipitation received in the study area. Apache cicadas may have significant effects on ecosystem functioning via effects on water transport and thus act as a critical-link species in this southwest desert riverine ecosystem. Cicadas emerged later within the cottonwood-willow stand than in relatively open saltcedar-mesquite stands; this difference in temporal dynamics would affect their availability to several insectivorous bird species and may help explain the birds' recent declines. Resource managers in this region should be sensitive to the multiple and strong effects that Apache cicadas may have on ecosystem structure and functioning.

  11. Revisiting the link between breeding effort and oxidative balance through field evaluation of two sympatric sibling insect species.

    PubMed

    Rey, Benjamin; Pélisson, Pierre-François; Bel-Venner, Marie-Claude; Voituron, Yann; Venner, Samuel

    2015-03-01

    The idea that oxidative stress could be a major force governing evolutionary trade-offs has recently been challenged by experimental approaches in laboratory conditions, triggering extensive debates centered on theoretical and methodological issues. Here, we revisited the link between oxidative stress and reproduction by measuring multiple antioxidant and oxidative damages in wild-caught females of two sibling weevil species (Curculio elephas, C. glandium). The strength of our study arised from (1) studied species that were sympatric and exploited similar resource, but displayed contrasting reproductive strategies and (2) individuals were sampled throughout adult life so as to relate oxidative status to breeding effort. We found that the short-lived C. elephas sacrifices red-ox homeostasis for immediate reproduction upon emergence as characterized by low antioxidant defenses and elevated oxidative damage. Comparatively, C. glandium massively invests in antioxidant and maintains low oxidative damage, which may contribute to their extended prereproductive period. Intriguingly, we also reveal, for the first time in a field study, an unexpected reactivation of antioxidant defenses with the onset of reproduction. Our results thus support the existence of a strong, but complex relationship between oxidative stress and life-history evolution and highlight the need for a finer-scale picture of antioxidant strategies. PMID:25521015

  12. Molecular Determinants of Species Specificity in the Coronavirus Receptor Aminopeptidase N (CD13): Influence of N-Linked Glycosylation

    PubMed Central

    Wentworth, David E.; Holmes, Kathryn V.

    2001-01-01

    Aminopeptidase N (APN), a 150-kDa metalloprotease also called CD13, serves as a receptor for serologically related coronaviruses of humans (human coronavirus 229E [HCoV-229E]), pigs, and cats. These virus-receptor interactions can be highly species specific; for example, the human coronavirus can use human APN (hAPN) but not porcine APN (pAPN) as its cellular receptor, and porcine coronaviruses can use pAPN but not hAPN. Substitution of pAPN amino acids 283 to 290 into hAPN for the corresponding amino acids 288 to 295 introduced an N-glycosylation sequon at amino acids 291 to 293 that blocked HCoV-229E receptor activity of hAPN. Substitution of two amino acids that inserted an N-glycosylation site at amino acid 291 also resulted in a mutant hAPN that lacked receptor activity because it failed to bind HCoV-229E. Single amino acid revertants that removed this sequon at amino acids 291 to 293 but had one or five pAPN amino acid substitution(s) in this region all regained HCoV-229E binding and receptor activities. To determine if other N-linked glycosylation differences between hAPN, feline APN (fAPN), and pAPN account for receptor specificity of pig and cat coronaviruses, a mutant hAPN protein that, like fAPN and pAPN, lacked a glycosylation sequon at 818 to 820 was studied. This sequon is within the region that determines receptor activity for porcine and feline coronaviruses. Mutant hAPN lacking the sequon at amino acids 818 to 820 maintained HCoV-229E receptor activity but did not gain receptor activity for porcine or feline coronaviruses. Thus, certain differences in glycosylation between coronavirus receptors from different species are critical determinants in the species specificity of infection. PMID:11559807

  13. Cytotoxic bile acids, but not cytoprotective species, inhibit the ordering effect of cholesterol in model membranes at physiologically active concentrations.

    PubMed

    Mello-Vieira, João; Sousa, Tânia; Coutinho, Ana; Fedorov, Aleksander; Lucas, Susana D; Moreira, Rui; Castro, Rui E; Rodrigues, Cecília M P; Prieto, Manuel; Fernandes, Fábio

    2013-09-01

    Submillimolar concentrations of cytotoxic bile acids (BAs) induce cell death via apoptosis. On the other hand, several cytoprotective BAs were shown to prevent apoptosis in the same concentration range. Still, the mechanisms by which BAs trigger these opposite signaling effects remain unclear. This study was aimed to determine if cytotoxic and cytoprotective BAs, at physiologically active concentrations, are able to modulate the biophysical properties of lipid membranes, potentially translating into changes in the apoptotic threshold of cells. Binding of BAs to membranes was assessed through the variation of fluorescence parameters of suitable derivatized BAs. These derivatives partitioned with higher affinity to liquid disordered than to the cholesterol-enriched liquid ordered domains. Unlabeled BAs were also shown to have a superficial location upon interaction with the lipid membrane. Additionally, the interaction of cytotoxic BAs with membranes resulted in membrane expansion, as concluded from FRET data. Moreover, it was shown that cytotoxic BAs were able to significantly disrupt the ordering of the membrane by cholesterol at physiologically active concentrations of the BA, an effect not associated with cholesterol removal. On the other hand, cytoprotective bile acids had no effect on membrane properties. It was concluded that, given the observed effects on membrane rigidity, the apoptotic activity of cytotoxic BAs could be potentially associated with changes in plasma membrane organization (e.g. modulation of lipid domains) or with an increase in mitochondrial membrane affinity for apoptotic proteins. PMID:23747364

  14. Relaxin concentrations in serum and urine of endangered species: correlations with physiologic events and use as a marker of pregnancy.

    PubMed

    Steinetz, Bernard G; Brown, Janine L; Roth, Terri L; Czekala, Nancy

    2005-05-01

    Many mammalian species are facing extinction due to problems created by human encroachment, agriculture, pollution, and willful slaughter. Among those at risk are the Asian and African elephant, Sumatran rhinoceros, and giant panda. Conservation groups try to save species in the wild by preserving habitat and limiting animal-human conflicts, often with limited success. Another alternative is to preserve the extant gene pool through captive breeding as a hedge against extinction. Measurement of circulating reproductive hormones is impractical for most wildlife species; determination of urinary or fecal hormone metabolites provides a more viable approach. To aid breeding management, one important tool is the ability to diagnose and monitor pregnancy, especially in species with long gestations (e.g., rhinos over 15 mo and elephants over 20 mo). Unfortunately, measuring progestins often is not useful diagnostically, because concentrations are similar during at least part of the pregnancy and the nonpregnant luteal phase in some species (e.g., elephants, rhinoceroses, and giant pandas). As serum relaxin reliably distinguishes between pregnancy and pseudopregnancy in bitches, relaxin measurement might also provide a method for detecting a successful pregnancy in endangered species. Appropriate immunoassay reagents have enabled the estimation of relaxin concentrations in the serum of elephants and rhinos and the determination of pregnancy establishment and the outcome. Relaxin was also detected in panda serum and urine. However, the extreme variability of the time between observed mating and parturition and the confounding factors of delayed implantation, pseudopregnancy, and frequent fetal resorptions made it impossible to use the panda relaxin data as a specific marker of pregnancy. PMID:15956734

  15. Linking size-dependent growth and mortality with architectural traits across 145 co-occurring tropical tree species.

    PubMed

    Iida, Yoshiko; Poorter, Lourens; Sterck, Frank; Kassim, Abd Rahman; Potts, Matthew D; Kubo, Takuya; Kohyama, Takashi S

    2014-02-01

    Tree architecture, growth, and mortality change with increasing tree size and associated light conditions. To date, few studies have quantified how size-dependent changes in growth and mortality rates co-vary with architectural traits, and how such size-dependent changes differ across species and possible light capture strategies. We applied a hierarchical Bayesian model to quantify size-dependent changes in demographic rates and correlated demographic rates and architectural traits for 145 co-occurring Malaysian rain-forest tree species covering a wide range of tree sizes. Demographic rates were estimated using relative growth rate in stem diameter (RGR) and mortality rate as a function of stem diameter. Architectural traits examined were adult stature measured as the 95-percentile of the maximum stem diameter (upper diameter), wood density, and three tree architectural variables: tree height, foliage height, and crown width. Correlations between demographic rates and architectural traits were examined for stem diameters ranging from 1 to 47 cm. As a result, RGR and mortality varied significantly with increasing stem diameter across species. At smaller stem diameters, RGR was higher for tall trees with wide crowns, large upper diameter, and low wood density. Increased mortality was associated with low wood density at small diameters, and associated with small upper diameter and wide crowns over a wide range of stem diameters. Positive correlations between RGR and mortality were found over the whole range of stem diameters, but they were significant only at small stem diameters. Associations between architectural traits and demographic rates were strongest at small stem diameters. In the dark understory of tropical rain forests, the limiting amount of light is likely to make the interspecific difference in the effects of functional traits on demography more clear. Demographic performance is therefore tightly linked with architectural traits such as adult stature

  16. Physiological impacts of soil pollution and arsenic uptake in three plant species: Agrostis capillaris, Solanum nigrum and Vicia faba.

    PubMed

    Austruy, A; Wanat, N; Moussard, C; Vernay, P; Joussein, E; Ledoigt, G; Hitmi, A

    2013-04-01

    In order to revegetate an industrial soil polluted by trace metals and metalloids (As, Pb, Cu, Cd, Sb), the impact of pollution on three plant species, Solanum nigrum and Agrostis capillaris, both native species in an industrial site, and Vicia faba, a plant model species, is studied. Following the study of soil pollution from the industrial wasteland of Auzon, it appears that the As is the principal pollutant. Particular attention is given to this metalloid, both in its content and its speciation in the soil that the level of its accumulation in plants. In V. faba and A. capillaris, the trace metals and metalloids inhibit the biomass production and involve a lipid peroxidation in the leaves. Furthermore, these pollutants cause a photosynthesis perturbation by stomatal limitations and a dysfunction of photosystem II. Whatever the plant, the As content is less than 0.1 percent of dry matter, the majority of As absorbed is stored in the roots which play the role of trap organ. In parallel, the culture of S. nigrum decreases significantly the exchangeable and weakly adsorbed fraction of As in rhizospheric soil. This study has highlighted the ability of tolerance to trace metals of S. nigrum and to a lesser extent A. capillaris. Our data indicate that V. faba is not tolerant to soil pollution and is not a metallophyte species. PMID:23321366

  17. Phylogenetic divergence morphological and physiological differences distinguish a new neotyphodium endophyte species in the grass bromus auleticus from South America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungi of genus Neotyphodium are systemic, constitutive, symbionts of grasses of subfamily Pooideae. In the southern hemisphere most of these asexual endophytes are the result of the hybridization between two sexual species, Epichloe festucae and E. typhina, from the northern hemisphere. However ...

  18. Effects of UV-B radiation on phenolic composition and deposition patterns and leaf physiology in three Eastern tree species

    NASA Astrophysics Data System (ADS)

    Sullivan, Joseph H.; Gitz, Dennis C.; Peek, Michael S.; McElrone, Andrew J.

    2002-01-01

    Quantitative changes in foliar chemistry in response to UVB radiation are frequently reported but less is known about the qualitative changes in putative UV-screening compounds. It has also not been conclusively shown whether qualitative differences in screening compounds or differences in localization patterns influences the sensitivity of plants to damage from UVB radiation. In this study we evaluated the chemical composition and deposition patterns of UV-absorbing compounds in three tree species and assayed these species for possible effects on gas exchange and photosynthetic carbon assimilation. Branches of mature trees of sweetgum (Liquidambar styraciflua), tulip poplar (Liriodendron tulipifera) and red maple (Acer rubrum) were exposed to supplemental levels of UVB radiation over three growing seasons. Controls for UVA were also measured by exposing branches to supplemental UVA only, and additional branches not irradiated were also used for controls. These species demonstrated contrasting chemical composition and deposition patterns with poplar being the most responsive in terms of epidermal accumulation of phenolics including flavonols and chlorogenic acid and hydroxycinnamates. Sweetgum and red maple showed increases primarily in hydroxycinnamates, particularly in the mesophyll in red maple. Leaf area was marginally influenced by UV exposure level. Assimilation was generally not reduced by UVB radiation in these species and was enhanced in red maple by both UVB and UVA and by UVA in sweetgum. These finding are consistent with a hypothesis that epidermal attenuation of UVB would only be reduced in poplar, which accumulated the additional epidermal screening compounds. It is possible that photosynthetic efficiency was enhanced in red maple by the increased absorption of blue light within the mesophyll. Stomatal conductance was generally reduced, and this led to an increase in water use efficiency in red maple and poplar.

  19. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

    PubMed

    Soolanayakanahally, Raju Y; Guy, Robert D; Street, Nathaniel R; Robinson, Kathryn M; Silim, Salim N; Albrectsen, Benedicte R; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g s) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ(13)C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects. PMID:26236324

  20. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens

    PubMed Central

    Soolanayakanahally, Raju Y.; Guy, Robert D.; Street, Nathaniel R.; Robinson, Kathryn M.; Silim, Salim N.; Albrectsen, Benedicte R.; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (gs) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ13C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects. PMID:26236324

  1. Conservation physiology of animal migration.

    PubMed

    Lennox, Robert J; Chapman, Jacqueline M; Souliere, Christopher M; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D; Cooke, Steven J

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  2. Conservation physiology of animal migration

    PubMed Central

    Lennox, Robert J.; Chapman, Jacqueline M.; Souliere, Christopher M.; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D.; Cooke, Steven J.

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  3. Assessments at multiple levels of biological organization allow for an integrative determination of physiological tolerances to turbidity in an endangered fish species

    PubMed Central

    Hasenbein, Matthias; Fangue, Nann A.; Geist, Juergen; Komoroske, Lisa M.; Truong, Jennifer; McPherson, Rina; Connon, Richard E.

    2016-01-01

    Turbidity can influence trophic levels by altering species composition and can potentially affect fish feeding strategies and predator–prey interactions. The estuarine turbidity maximum, described as an area of increased suspended particles, phytoplankton and zooplankton, generally represents a zone with higher turbidity and enhanced food sources important for successful feeding and growth in many fish species. The delta smelt (Hypomesus transpacificus) is an endangered, pelagic fish species endemic to the San Francisco Estuary and Sacramento–San Joaquin River Delta, USA, where it is associated with turbid waters. Turbidity is known to play an important role for the completion of the species' life cycle; however, turbidity ranges in the Delta are broad, and specific requirements for this fish species are still unknown. To evaluate turbidity requirements for early life stages, late-larval delta smelt were maintained at environmentally relevant turbidity levels ranging from 5 to 250 nephelometric turbidity units (NTU) for 24 h, after which a combination of physiological endpoints (molecular biomarkers and cortisol), behavioural indices (feeding) and whole-organism measures (survival) were determined. All endpoints delivered consistent results and identified turbidities between 25 and 80 NTU as preferential. Delta smelt survival rates were highest between 12 and 80 NTU and feeding rates were highest between 25 and 80 NTU. Cortisol levels indicated minimal stress between 35 and 80 NTU and were elevated at low turbidities (5, 12 and 25 NTU). Expression of stress-related genes indicated significant responses for gst, hsp70 and glut2 in high turbidities (250 NTU), and principal component analysis on all measured genes revealed a clustering of 25, 35, 50 and 80 NTU separating the medium-turbidity treatments from low- and high-turbidity treatments. Taken together, these data demonstrate that turbidity levels that are either too low or too high affect

  4. Assessments at multiple levels of biological organization allow for an integrative determination of physiological tolerances to turbidity in an endangered fish species.

    PubMed

    Hasenbein, Matthias; Fangue, Nann A; Geist, Juergen; Komoroske, Lisa M; Truong, Jennifer; McPherson, Rina; Connon, Richard E

    2016-01-01

    Turbidity can influence trophic levels by altering species composition and can potentially affect fish feeding strategies and predator-prey interactions. The estuarine turbidity maximum, described as an area of increased suspended particles, phytoplankton and zooplankton, generally represents a zone with higher turbidity and enhanced food sources important for successful feeding and growth in many fish species. The delta smelt (Hypomesus transpacificus) is an endangered, pelagic fish species endemic to the San Francisco Estuary and Sacramento-San Joaquin River Delta, USA, where it is associated with turbid waters. Turbidity is known to play an important role for the completion of the species' life cycle; however, turbidity ranges in the Delta are broad, and specific requirements for this fish species are still unknown. To evaluate turbidity requirements for early life stages, late-larval delta smelt were maintained at environmentally relevant turbidity levels ranging from 5 to 250 nephelometric turbidity units (NTU) for 24 h, after which a combination of physiological endpoints (molecular biomarkers and cortisol), behavioural indices (feeding) and whole-organism measures (survival) were determined. All endpoints delivered consistent results and identified turbidities between 25 and 80 NTU as preferential. Delta smelt survival rates were highest between 12 and 80 NTU and feeding rates were highest between 25 and 80 NTU. Cortisol levels indicated minimal stress between 35 and 80 NTU and were elevated at low turbidities (5, 12 and 25 NTU). Expression of stress-related genes indicated significant responses for gst, hsp70 and glut2 in high turbidities (250 NTU), and principal component analysis on all measured genes revealed a clustering of 25, 35, 50 and 80 NTU separating the medium-turbidity treatments from low- and high-turbidity treatments. Taken together, these data demonstrate that turbidity levels that are either too low or too high affect delta

  5. Simulation Method Linking Dense Microalgal Culture Spectral Properties in the 400-750 nm Range to the Physiology of the Cells.

    PubMed

    Bellini, Sarah; Bendoula, Ryad; Le Floc'h, Emilie; Carré, Claire; Mas, Sébastien; Vidussi, Francesca; Fouilland, Eric; Roger, Jean-Michel

    2016-06-01

    This work describes a method to model the optical properties over the (400-750 nm) spectral range of a dense microalgal culture using the chemical and physical properties of the algal cells. The method was based on a specific program called AlgaSim coupled with the adding-doubling method: at the individual cell scale, AlgaSim simulates the spectral properties of one model, three-layer spherical algal cell from its size and chemical composition. As a second step, the adding-doubling method makes it possible to retrieve the total transmittance of the algal medium from the optical properties of the individual algal cells. The method was tested by comparing the simulated total transmittance spectra for dense marine microalgal cultures of Isochrysis galbana (small flagellates) and Phaeodactylum tricornutum (diatoms) to spectra measured using an experimental spectrophotometric setup. Our study revealed that the total transmittance spectra simulated for the quasi-spherical cells of Isochrysis galbana were in good agreement with the measured spectra over the whole spectral range. For Phaeodactylum tricornutum, large differences between simulated and measured spectra were observed over the blue part of the transmittance spectra, probably due to non-spherical shape of the algal cells. Prediction of the algal cell density, mean size and pigment composition from the total transmittance spectra measured on algal samples was also investigated using the reversal of the method. Mean cell size was successfully predicted for both species. The cell density was also successfully predicted for spherical Isochrysis galbana, with a relative error below 7%, but not for elongated Phaeodactylum tricornutum with a relative error up to 26%. The pigments total quantity and composition, the carotenoids:chlorophyll ratio in particular, were also successfully predicted for Isochrysis galbana with a relative error below 8%. However, the pigment predictions and measurements for Phaeodactylum

  6. Recovery of Physiological Traits in Saplings of Invasive Bischofia Tree Compared with Three Species Native to the Bonin Islands under Successive Drought and Irrigation Cycles

    PubMed Central

    Yazaki, Kenichi; Kuroda, Katsushi; Nakano, Takashi; Kitao, Mitsutoshi; Tobita, Hiroyuki; Ogasa, Mayumi Y.; Ishida, Atsushi

    2015-01-01

    Partial leaf shedding induced by hydraulic failure under prolonged drought can prevent excess water consumption, resulting in delayed recovery of carbon productivity following rainfall. To understand the manner of water use of invasive species in oceanic island forests under a fluctuating water regime, leaf shedding, multiple physiological traits, and the progress of embolism in the stem xylem under repeated drought-irrigation cycles were examined in the potted saplings of an invasive species, Bischofia javanica Blume, and three endemic native species, Schima mertensiana (Sieb. Et Zucc,) Koitz., Hibiscus glaber Matsum, and Distylium lepidotum Nakai, from the Bonin Islands, Japan. The progress of xylem embolism was observed by cryo-scanning electron microscopy. The samples exhibited different processes of water saving and drought tolerance based on the different combinations of partial leaf shedding involved in embolized conduits following repeated de-rehydration. Predawn leaf water potential largely decreased with each successive drought-irrigation cycle for all tree species, except for B. javanica. B. javanica shed leaves conspicuously under drought and showed responsive stomatal conductance to VPD, which contributed to recover leaf gas exchange in the remaining leaves, following a restored water supply. In contrast, native tree species did not completely recover photosynthetic rates during the repeated drought-irrigation cycles. H. glaber and D. lepidotum preserved water in vessels and adjusted leaf osmotic rates but did not actively shed leaves. S. mertensiana exhibited partial leaf shedding during the first cycle with an osmotic adjustment, but they showed less responsive stomatal conductance to VPD. Our data indicate that invasive B. javanica saplings can effectively use water supplied suddenly under drought conditions. We predict that fluctuating precipitation in the future may change tree distributions even in mesic or moist sites in the Bonin Islands. PMID

  7. Behavioural and Physiological Implications of a Burrow-dwelling Lifestyle for Two Species of Upogebiid Mud-shrimp (Crustacea: Thalassinidea)

    NASA Astrophysics Data System (ADS)

    Astall, C. M.; Taylor, A. C.; Atkinson, R. J. A.

    1997-02-01

    Upogebia stellataand U. deltaura(Crustacea: Thalassinidea) construct burrows in nearshore sediments in U.K. waters. Burrow structure is similar in both species; the basic burrow consisting of a two-opening, U-shaped section with a vertical shaft descending from the mid-point of the U. This structure may be variously elaborated. Burrow cross-section is circular, dilations allow turning by somersaulting and surface openings are often constricted. Conditions within the burrows are usually hypoxic and hypercapnic. Burrow water PO 2in the parts normally occupied by the mud-shrimp was between 80-110 Torr, but was much lower (10-45 Torr) in the deepest, poorly-irrigated parts. Both species irrigate their burrows by episodes of pleopod beating of variable duration (mean=8·5±3·5 min and 2·8±0·5 min for U. deltauraand U. stellata, respectively), which draws oxygenated water into the burrow and also particulate food for suspension feeding. When exposed to hypoxia, U. deltauraand U. stellatawere able to maintain their rates of oxygen consumption approximately constant over a wide range of PO 2( Pc=30-50 Torr). Under these conditions, there was a pronounced increase in scaphognathite beat rate but heart rate remained relatively constant. Below the Pc, however, both rates declined.

  8. Cross-Species Extrapolation of Uptake and Disposition of Neutral Organic Chemicals in Fish Using a Multispecies Physiologically-Based Toxicokinetic Model Framework.

    PubMed

    Brinkmann, Markus; Schlechtriem, Christian; Reininghaus, Mathias; Eichbaum, Kathrin; Buchinger, Sebastian; Reifferscheid, Georg; Hollert, Henner; Preuss, Thomas G

    2016-02-16

    The potential to bioconcentrate is generally considered to be an unwanted property of a substance. Consequently, chemical legislation, including the European REACH regulations, requires the chemical industry to provide bioconcentration data for chemicals that are produced or imported at volumes exceeding 100 tons per annum or if there is a concern that a substance is persistent, bioaccumulative, and toxic. For the filling of the existing data gap for chemicals produced or imported at levels that are below this stipulated volume, without the need for additional animal experiments, physiologically-based toxicokinetic (PBTK) models can be used to predict whole-body and tissue concentrations of neutral organic chemicals in fish. PBTK models have been developed for many different fish species with promising results. In this study, we developed PBTK models for zebrafish (Danio rerio) and roach (Rutilus rutilus) and combined them with existing models for rainbow trout (Onchorhynchus mykiss), lake trout (Salvelinus namaycush), and fathead minnow (Pimephales promelas). The resulting multispecies model framework allows for cross-species extrapolation of the bioaccumulative potential of neutral organic compounds. Predictions were compared with experimental data and were accurate for most substances. Our model can be used for probabilistic risk assessment of chemical bioaccumulation, with particular emphasis on cross-species evaluations. PMID:26794144

  9. Molecular Scanning and Morpho-Physiological Dissection of Component Mechanism in Lens Species in Response to Aluminium Stress

    PubMed Central

    Singh, Dharmendra; Pal, Madan; Singh, Chandan Kumar; Taunk, Jyoti; Jain, Priyanka; Chaturvedi, Ashish Kumar; Maurya, Sadhana; Karwa, Sourabh; Singh, Rajendra; Tomar, Ram Sewak Singh; Nongthombam, Rita; Chongtham, Nandini; Singh, Moirangthem Premjit

    2016-01-01

    Aluminium (Al) stress was imposed on 285 lentil genotypes at seedling stage under hydroponics to study its effects on morpho-physiological traits where resistant cultigens and wilds showed minimum reduction in root and shoot length and maximum root re-growth (RRG) after staining. Molecular assortment based on 46 simple sequence repeat (SSR) markers clustered the genotypes into 11 groups, where wilds were separated from the cultigens. Genetic diversity and polymorphism information content (PIC) varied between 0.148–0.775 and 0.140–0.739, respectively. Breeding lines which were found to be most resistant (L-7903, L-4602); sensitive cultivars (BM-4, L-4147) and wilds ILWL-185 (resistant), ILWL-436 (sensitive) were grouped into different clusters. These genotypes were also separated on the basis of population structure and Jaccard’s similarity index and analysed to study Al resistance mechanism through determination of different attributes like localization of Al and callose, lipid peroxidation, secretion of organic acids and production of antioxidant enzymes. In contrast to sensitive genotypes, in resistant ones most of the Al was localized in the epidermal cells, where its movement to apoplastic region was restricted due to release of citrate and malate. Under acidic field conditions, resistant genotypes produced maximum seed yield/plant as compared to sensitive genotypes at two different locations i.e. Imphal, Manipur, India and Basar, Arunanchal Pradesh, India during 2012–13, 2013–14 and 2014–15. These findings suggest that Al stress adaptation in lentil is through exclusion mechanism and hybridization between the contrasting genotypes from distinct clusters can help in development of resistant varieties. PMID:27467074

  10. Molecular Scanning and Morpho-Physiological Dissection of Component Mechanism in Lens Species in Response to Aluminium Stress.

    PubMed

    Singh, Dharmendra; Pal, Madan; Singh, Chandan Kumar; Taunk, Jyoti; Jain, Priyanka; Chaturvedi, Ashish Kumar; Maurya, Sadhana; Karwa, Sourabh; Singh, Rajendra; Tomar, Ram Sewak Singh; Nongthombam, Rita; Chongtham, Nandini; Singh, Moirangthem Premjit

    2016-01-01

    Aluminium (Al) stress was imposed on 285 lentil genotypes at seedling stage under hydroponics to study its effects on morpho-physiological traits where resistant cultigens and wilds showed minimum reduction in root and shoot length and maximum root re-growth (RRG) after staining. Molecular assortment based on 46 simple sequence repeat (SSR) markers clustered the genotypes into 11 groups, where wilds were separated from the cultigens. Genetic diversity and polymorphism information content (PIC) varied between 0.148-0.775 and 0.140-0.739, respectively. Breeding lines which were found to be most resistant (L-7903, L-4602); sensitive cultivars (BM-4, L-4147) and wilds ILWL-185 (resistant), ILWL-436 (sensitive) were grouped into different clusters. These genotypes were also separated on the basis of population structure and Jaccard's similarity index and analysed to study Al resistance mechanism through determination of different attributes like localization of Al and callose, lipid peroxidation, secretion of organic acids and production of antioxidant enzymes. In contrast to sensitive genotypes, in resistant ones most of the Al was localized in the epidermal cells, where its movement to apoplastic region was restricted due to release of citrate and malate. Under acidic field conditions, resistant genotypes produced maximum seed yield/plant as compared to sensitive genotypes at two different locations i.e. Imphal, Manipur, India and Basar, Arunanchal Pradesh, India during 2012-13, 2013-14 and 2014-15. These findings suggest that Al stress adaptation in lentil is through exclusion mechanism and hybridization between the contrasting genotypes from distinct clusters can help in development of resistant varieties. PMID:27467074

  11. Comparative physiology and fermentation performance of Saaz and Frohberg lager yeast strains and the parental species Saccharomyces eubayanus.

    PubMed

    Gibson, Brian R; Storgårds, Erna; Krogerus, Kristoffer; Vidgren, Virve

    2013-07-01

    Two distinct genetic groups (Saaz and Frohberg) exist within the hybrid Saccharomyces pastorianus (S. cerevisiae × S. eubayanus) taxon. However, physiological/technological differences that exist between the two groups are not known. Fermentative capability of the parental S. eubayanus has likewise never been studied. Here, 58 lager strains were screened to determine which hybrid group they belonged to, and selected strains were characterized to determine salient characteristics. In 15 °P all-malt wort fermentations at 22 °C, Frohberg strains showed greater growth and superior fermentation (80% apparent attenuation, 6.5% alcohol by volume in 3-4 days) compared to all other strains and maintained highest viability values (>93%). Fermentation with S. eubayanus was poor at the same temperature (33% apparent attenuation, 2.7% alcohol by volume at 6 days and viability reduced to 75%). Saaz strains and S. eubayanus were the least sensitive to cold (10 °C), though this did not translate to greater fermentation performance. Fermentation with S. eubayanus was poor at 10 °C but equal to or greater than that of the Saaz strains. Performance of Saaz yeast/S. eubayanus was limited by an inability to use wort maltotriose. [(14)C]-Maltotriose transport assays also showed negligible activity in these strains (≤0.5 µmol min(-1) g(-1) dry yeast). Beers from Saaz fermentations were characterized by two- to sixfold lower production of the flavour compounds methyl butanol, ethyl acetate and 3-methylbutyl acetate compared to Frohberg strains. Higher alcohol and ester production by S. eubayanus was similar to that of Frohberg strains. PMID:23695993

  12. Physiology-based prognostic modeling of the influence of changes in precipitation on a keystone dryland plant species.

    PubMed

    Coe, Kirsten K; Sparks, Jed P

    2014-12-01

    Fluctuations in mean annual precipitation (MAP) will strongly influence the ecology of dryland ecosystems in the future, yet, because individual precipitation events drive growth and resource availability for many dryland organisms, changes in intra-annual precipitation may disproportionately influence future dryland processes. This work examines the hypothesis that intra-annual precipitation changes will drive dryland productivity to a greater extent than changes to MAP. To test this hypothesis, we created a physiology-based model to predict the effects of precipitation change on a widespread biocrust moss that regulates soil structure, water retention, and nutrient cycling in drylands. First, we used the model to examine moss productivity over the next 100 years driven by alterations in MAP by ± 10, 20 and 30%, and changes in intra-annual precipitation (event size and frequency). Productivity increased as a function of MAP, but differed among simulations where intra-annual precipitation was manipulated under constant MAP. Supporting our hypothesis, this demonstrates that, even if MAP does not change, changes in the features of individual precipitation events can strongly influence long-term performance. Second, we used the model to examine 100-year productivity based on projected dryland precipitation from published global and regional models. These simulations predicted 25-63% reductions in productivity and increased moss mortality rates, declines that will likely alter water and nutrient cycling in dryland ecosystems. Intra-annual precipitation in model-based simulations was a stronger predictor of productivity compared to MAP, further supporting our hypothesis, and illustrating that intra-annual precipitation patterns may dominate dryland responses to altered precipitation in a future climate. PMID:25193314

  13. N-fertilization has different effects on the growth, carbon and nitrogen physiology, and wood properties of slow- and fast-growing Populus species

    PubMed Central

    Luo, Zhi-Bin

    2012-01-01

    To investigate how N-fertilization affects the growth, carbon and nitrogen (N) physiology, and wood properties of poplars with contrasting growth characteristics, slow-growing (Populus popularis, Pp) and fast-growing (P. alba×P. glandulosa, Pg) poplar saplings were exposed to different N levels. Above-ground biomass, leaf area, photosynthetic rates (A), instantaneous photosynthetic nitrogen use efficiency (PNUE i), chlorophyll and foliar sugar concentrations were higher in Pg than in Pp. Foliar nitrate reductase (NR) activities and root glutamate synthase (GOGAT) activities were higher in Pg than in Pp as were the N amount and NUE of new shoots. Lignin contents and calorific values of Pg wood were less than that of Pp wood. N-fertilization reduced root biomass of Pg more than of Pp, but increased leaf biomass, leaf area, A, and PNUEi of Pg more than of Pp. Among 13 genes involved in the transport of ammonium or nitrate or in N assimilation, transcripts showed more pronounced changes to N-fertilization in Pg than in Pp. Increases in NR activities and N contents due to N-fertilization were larger in Pg than in Pp. In both species, N-fertilization resulted in lower calorific values as well as shorter and wider vessel elements/fibres. These results suggest that growth, carbon and N physiology, and wood properties are more sensitive to increasing N availability in fast-growing poplars than in slow-growing ones, which is probably due to prioritized resource allocation to the leaves and accelerated N physiological processes in fast-growing poplars under higher N levels. PMID:23028021

  14. The effect of lichen-dominated biological soil crusts on growth and physiological characteristics of three plant species in a temperate desert of northwest China.

    PubMed

    Zhuang, W W; Serpe, M; Zhang, Y M

    2015-11-01

    Biocrusts (biological soil crusts) cover open spaces between vascular plants in most arid and semi-arid areas. Information on effects of biocrusts on seedling growth is controversial, and there is little information on their effects on plant growth and physiology. We examined impacts of biocrusts on growth and physiological characteristics of three habitat-typical plants, Erodium oxyrhynchum, Alyssum linifolium and Hyalea pulchella, growing in the Gurbantunggut Desert, northwest China. The influence of biocrusts on plant biomass, leaf area, leaf relative water content, photosynthesis, maximum quantum efficiency of PSII (F(v)/F(m)), chlorophyll, osmotic solutes (soluble sugars, protein, proline) and antioxidant enzymes (superoxide dismutase, catalase, peroxidase) was investigated on sites with or without biocrust cover. Biomass, leaf area, leaf water content, photosynthesis, F(v)/F(m) and chlorophyll content in crusted soils were higher than in uncrusted soils during early growth and lower later in the growth period. Soluble sugars, proline and antioxidant enzyme activity were always higher in crusted than in uncrusted soils, while soluble protein content was always lower. These findings indicate that biocrusts have different effects on these three ephemeral species during growth in this desert, primarily via effects on soil moisture, and possibly on soil nutrients. The influence of biocrusts changes during plant development: in early plant growth, biocrusts had either positive or no effect on growth and physiological parameters. However, biocrusts tended to negatively influence plants during later growth. Our results provide insights to explain why previous studies have found different effects of biocrusts on vascular plant growth. PMID:26084731

  15. Physiological and behavioural effects of imidacloprid on two ecologically relevant earthworm species (Lumbricus terrestris and Aporrectodea caliginosa).

    PubMed

    Dittbrenner, Nils; Triebskorn, Rita; Moser, Isabelle; Capowiez, Yvan

    2010-11-01

    Earthworms play key roles in soils and sub-lethal effects of environmental toxicants on these organisms should be taken seriously, since they might have detrimental effects on higher ecological levels. In laboratory experiments we have assessed sub-lethal effects (body mass change and cast production) of imidacloprid on two earthworm species commonly found in different agricultural soils (Lumbricus terrestris and Aporrectodea caliginosa). After 7 days of exposure in contaminated soil, a significant loss of body mass was found in both species exposed to imidacloprid concentrations as low as 0.66 mg kg(-1) dry soil. These losses ranged from 18.3 to 39% for A. caliginosa and from 7.4 to 32.4% for L. terrestris, respectively. Changes in cast production, a new biomarker previously validated using L. terrestris, was assessed by soil sieving using the recommended mesh size (5.6 mm) for L. terrestris and three different mesh sizes for A. caliginosa (5.6, 4 and 3.15 mm). The 4 mm mesh size proved to be the most suitable sieve size for A. caliginosa. Cast production increased by 26.2% in A. caliginosa and by 28.1% in L. terrestris at the lowest imidacloprid concentration tested (0.2 mg kg(-1) dry soil), but significantly decreased at higher concentrations (equal to and above 0.66 mg kg(-1) dry soil) in both earthworm species after the 7 days exposure experiment. These decreases in cast production ranged from 44.5 to 96.9% in A. caliginosa and from 42.4 to 95.7% in L. terrestris. The EC(50) for cast production were 0.84 (L. terrestris) and 0.76 mg kg(-1) dry soil (A. caliginosa), respectively. The detected sub-lethal effects were found close to the predicted environmental concentration (PEC) of imidacloprid, which is in the range of 0.33-0.66 mg kg(-1) dry soil. The biomarkers used in the present study, body mass change and changes in cast production, may be of ecological relevance and have shown high sensitivity for imidacloprid exposure of earthworms. The measurement of

  16. Can respiratory physiology predict thermal niches?

    PubMed

    Verberk, Wilco C E P; Bartolini, Fabrizio; Marshall, David J; Pörtner, Hans-O; Terblanche, John S; White, Craig R; Giomi, Folco

    2016-02-01

    Predicting species responses to global warming is the holy grail of climate change science. As temperature directly affects physiological rates, it is clear that a mechanistic understanding of species vulnerability should be grounded in organismal physiology. Here, we review what respiratory physiology can offer the field of thermal ecology, showcasing different perspectives on how respiratory physiology can help explain thermal niches. In water, maintaining adequate oxygen delivery to fuel the higher metabolic rates under warming conditions can become the weakest link, setting thermal tolerance limits. This has repercussions for growth and scaling of metabolic rate. On land, water loss is more likely to become problematic as long as O2 delivery and pH balance can be maintained, potentially constraining species in their normal activity. Therefore, high temperatures need not be lethal, but can still affect the energy intake of an animal, with concomitant consequences for long-term fitness. While respiratory challenges and adaptive responses are diverse, there are clear recurring elements such as oxygen uptake, CO2 excretion, and water homeostasis. We show that respiratory physiology has much to offer the field of thermal ecology and call for an integrative, multivariate view incorporating respiratory challenges, thermal responses, and energetic consequences. Fruitful areas for future research are highlighted. PMID:26333058

  17. Species-specific physiological response by the cold-water corals Lophelia pertusa and Madrepora oculata to variations within their natural temperature range

    NASA Astrophysics Data System (ADS)

    Naumann, Malik S.; Orejas, Covadonga; Ferrier-Pagès, Christine

    2014-01-01

    The scleractinian cold-water corals (CWC) Lophelia pertusa and Madrepora oculata represent two major deep-sea reef-forming species that act as key ecosystem engineers over a wide temperature range, extending from the northern Atlantic (ca. 5-9 °C) to the Mediterranean Sea (ca. 11-13 °C). Recent research suggests that environmental parameters, such as food supply, settling substrate availability or aragonite saturation state may represent important precursors controlling habitat suitability for CWC. However, the effect of one principal environmental factor, temperature, on CWC key physiological processes is still unknown. In order to evaluate this effect on calcification, respiration, and dissolved organic carbon (DOC) net flux, colonies of Mediterranean L. pertusa and M. oculata were acclimated in aquaria to three temperatures (12, 9 and 6 °C), by consecutive decrements of 1 month duration. L. pertusa and M. oculata maintained at Mediterranean control conditions (i.e. 12 °C) displayed constant rates, on average respiring 4.8 and 4.0 μmol O2 cm-2 coral surface area d-1, calcifying 22.3 and 12.3 μmol CaCO3 g-1 skeletal dry weight d-1 and net releasing 2.6 and 3.1 μmol DOC cm-2 coral surface area d-1, respectively. Respiration of L. pertusa was not affected by lowered temperatures, while M. oculata respiration declined significantly (by 48%) when temperature decreased to 9 °C and 6 °C relative to controls. L. pertusa calcification at 9 °C was similar to controls, but decreased significantly (by 58%) at 6 °C. For M. oculata, calcification declined by 41% at 9 °C and by 69% at 6 °C. DOC net flux was similar throughout the experiment for both CWC. These findings reveal species-specific physiological responses by CWC within their natural temperature range. L. pertusa shows thermal acclimation in respiration and calcification, while these mechanisms appear largely absent in M. oculata. Conclusively, species-specific thermal acclimation may significantly affect

  18. Extensive Gene Acquisition in the Extremely Psychrophilic Bacterial Species Psychroflexus torquis and the Link to Sea-Ice Ecosystem Specialism

    PubMed Central

    Feng, Shi; Powell, Shane M.; Wilson, Richard; Bowman, John P.

    2014-01-01

    Sea ice is a highly dynamic and productive environment that includes a diverse array of psychrophilic prokaryotic and eukaryotic taxa distinct from the underlying water column. Because sea ice has only been extensive on Earth since the mid-Eocene, it has been hypothesized that bacteria highly adapted to inhabit sea ice have traits that have been acquired through horizontal gene transfer (HGT). Here we compared the genomes of the psychrophilic bacterium Psychroflexus torquis ATCC 700755T, associated with both Antarctic and Arctic sea ice, and its closely related nonpsychrophilic sister species, P. gondwanensis ACAM 44T. Results show that HGT has occurred much more extensively in P. torquis in comparison to P. gondwanensis. Genetic features that can be linked to the psychrophilic and sea ice-specific lifestyle of P. torquis include genes for exopolysaccharide (EPS) and polyunsaturated fatty acid (PUFA) biosynthesis, numerous specific modes of nutrient acquisition, and proteins putatively associated with ice-binding, light-sensing (bacteriophytochromes), and programmed cell death (metacaspases). Proteomic analysis showed that several genes associated with these traits are highly translated, especially those involved with EPS and PUFA production. Because most of the genes relating to the ability of P. torquis to dwell in sea-ice ecosystems occur on genomic islands that are absent in closely related P. gondwanensis, its adaptation to the sea-ice environment appears driven mainly by HGT. The genomic islands are rich in pseudogenes, insertional elements, and addiction modules, suggesting that gene acquisition is being followed by a process of genome reduction potentially indicative of evolving ecosystem specialism. PMID:24391155

  19. Enzyme-linked immunosorbent assay with major outer membrane proteins of Brucella melitensis to measure immune response to Brucella species.

    PubMed Central

    Hunter, S B; Bibb, W F; Shih, C N; Kaufmann, A F; Mitchell, J R; McKinney, R M

    1986-01-01

    We developed an enzyme-linked immunosorbent assay (ELISA) system to measure human immunoglobulin G (IgG) and IgM response to the major outer membrane proteins of Brucella melitensis. The ELISA was more sensitive in detecting antibody than a standard microagglutination (MA) test with B. abortus antigen. Of 101 sera from persons with suspected brucellosis, 79 (78.2%) gave ELISA IgM titers greater than or equal to the B. abortus MA titer without 2-mercaptoethanol (2ME), which measures both IgM and IgG. Of the 101 sera, 97% gave ELISA IgG titers greater than or equal to the MA with 2ME titer. A total of 58 sera, drawn from 11 human patients from 1 to 29 weeks after onset of brucellosis, gave higher geometric mean titers for the ELISA IgG test than for the MA with 2ME test. These 58 sera also gave ELISA IgM geometric mean titers that were greater than or within one doubling dilution of the geometric mean titers of MA without 2ME. In addition to detecting antibody response to B. abortus, B. melitensis, and B. suis, the ELISA was sensitive to antibody response to human and canine infections with B. canis. The B. canis antibody response is not detected by the MA test with B. abortus antigen. The ELISA, with a standard preparation of major outer membrane proteins of B. melitensis as antigen, appears to be useful in measuring antibody response in humans to infections by all species of Brucella known to infect humans. PMID:3095364

  20. A quantitative method to monitor reactive oxygen species production by electron paramagnetic resonance in physiological and pathological conditions.

    PubMed

    Mrakic-Sposta, Simona; Gussoni, Maristella; Montorsi, Michela; Porcelli, Simone; Vezzoli, Alessandra

    2014-01-01

    The growing interest in the role of Reactive Oxygen Species (ROS) and in the assessment of oxidative stress in health and disease clashes with the lack of consensus on reliable quantitative noninvasive methods applicable. The study aimed at demonstrating that a recently developed Electron Paramagnetic Resonance microinvasive method provides direct evidence of the "instantaneous" presence of ROS returning absolute concentration levels that correlate with "a posteriori" assays of ROS-induced damage by means of biomarkers. The reliability of the choice to measure ROS production rate in human capillary blood rather than in plasma was tested (step I). A significant (P < 0.01) linear relationship between EPR data collected on capillary blood versus venous blood (R (2) = 0.95), plasma (R (2) = 0.82), and erythrocytes (R (2) = 0.73) was found. Then (step II) ROS production changes of various subjects' categories, young versus old and healthy versus pathological at rest condition, were found significantly different (range 0.0001-0.05 P level). The comparison of the results with antioxidant capacity and oxidative damage biomarkers concentrations showed that all changes indicating increased oxidative stress are directly related to ROS production increase. Therefore, the adopted method may be an automated technique for a lot of routine in clinical trials. PMID:25374651

  1. A Quantitative Method to Monitor Reactive Oxygen Species Production by Electron Paramagnetic Resonance in Physiological and Pathological Conditions

    PubMed Central

    Mrakic-Sposta, Simona; Gussoni, Maristella; Montorsi, Michela; Porcelli, Simone; Vezzoli, Alessandra

    2014-01-01

    The growing interest in the role of Reactive Oxygen Species (ROS) and in the assessment of oxidative stress in health and disease clashes with the lack of consensus on reliable quantitative noninvasive methods applicable. The study aimed at demonstrating that a recently developed Electron Paramagnetic Resonance microinvasive method provides direct evidence of the “instantaneous” presence of ROS returning absolute concentration levels that correlate with “a posteriori” assays of ROS-induced damage by means of biomarkers. The reliability of the choice to measure ROS production rate in human capillary blood rather than in plasma was tested (step I). A significant (P < 0.01) linear relationship between EPR data collected on capillary blood versus venous blood (R2 = 0.95), plasma (R2 = 0.82), and erythrocytes (R2 = 0.73) was found. Then (step II) ROS production changes of various subjects' categories, young versus old and healthy versus pathological at rest condition, were found significantly different (range 0.0001–0.05 P level). The comparison of the results with antioxidant capacity and oxidative damage biomarkers concentrations showed that all changes indicating increased oxidative stress are directly related to ROS production increase. Therefore, the adopted method may be an automated technique for a lot of routine in clinical trials. PMID:25374651

  2. Reproduction, Physiology and Biochemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter focuses on the reproduction, physiology, and biochemistry of the root-knot nematodes. The extensive amount of information on the reproduction and cytogenetics of species of Meloidogyne contrasts with the limited information on physiology, biochemistry, and biochemical pathways. In commo...

  3. Linking science and policy to prevent the spread of invasive species from the ballast water discharge of ships

    EPA Science Inventory

    Huamn activites are causing the global redistribution of species at a historically unprecedented rates. In marine environments, a major vector of nonindigenous species introduction is commercial shipping, including the ballast water of ocean going vessels. The introduction of n...

  4. Differential Growth Responses to Water Balance of Coexisting Deciduous Tree Species Are Linked to Wood Density in a Bolivian Tropical Dry Forest

    PubMed Central

    Mendivelso, Hooz A.; Camarero, J. Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

  5. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    PubMed

    Mendivelso, Hooz A; Camarero, J Julio; Royo Obregón, Oriol; Gutiérrez, Emilia; Toledo, Marisol

    2013-01-01

    A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability. PMID:24116001

  6. A new procedure for determining the genetic basis of a physiological process in a non-model species, illustrated by cold induced angiogenesis in the carp

    PubMed Central

    Herbert, John MJ; Buffa, Francesca M; Vorschmitt, Henrik; Egginton, Stuart; Bicknell, Roy

    2009-01-01

    Background Physiological processes occur in many species for which there is yet no sequenced genome and for which we would like to identify the genetic basis. For example, some species increase their vascular network to minimise the effects of reduced oxygen diffusion and increased blood viscosity associated with low temperatures. Since many angiogenic and endothelial genes have been discovered in man, functional homolog relationships between carp, zebrafish and human were used to predict the genetic basis of cold-induced angiogenesis in Cyprinus Carpio (carp). In this work, carp sequences were collected and built into contigs. Human-carp functional homolog relationships were derived via zebrafish using a new Conditional Stepped Reciprocal Best Hit (CSRBH) protocol. Data sources including publications, Gene Ontology and cDNA libraries were then used to predict the identity of known or potential angiogenic genes. Finally, re-analyses of cold carp microarray data identified carp genes up-regulated in response to low temperatures in heart and muscle. Results The CSRBH approach outperformed all other methods and attained 8,726 carp to human functional homolog relationships for 16,650 contiguous sequences. This represented 3,762 non-redundant genes and 908 of them were predicted to have a role in angiogenesis. The total number of up-regulated differentially expressed genes was 698 and 171 of them were putatively angiogenic. Of these, 5 genes representing the functional homologs NCL, RHOA, MMP9, GRN and MAPK1 are angiogenesis-related genes expressed in response to low temperature. Conclusion We show that CSRBH functional homologs relationships and re-analyses of gene expression data can be combined in a non-model species to predict genes of biological interest before a genome sequence is fully available. Programs to run these analyses locally are available from . PMID:19852815

  7. Leaf morphological and physiological adaptations of a deciduous oak (Quercus faginea Lam.) to the Mediterranean climate: a comparison with a closely related temperate species (Quercus robur L.).

    PubMed

    Peguero-Pina, José Javier; Sisó, Sergio; Sancho-Knapik, Domingo; Díaz-Espejo, Antonio; Flexas, Jaume; Galmés, Jeroni; Gil-Pelegrín, Eustaquio

    2016-03-01

    'White oaks'--one of the main groups of the genus Quercus L.--are represented in western Eurasia by the 'roburoid oaks', a deciduous and closely related genetic group that should have an Arcto-Tertiary origin under temperate-nemoral climates. Nowadays, roburoid oak species such as Quercus robur L. are still present in these temperate climates in Europe, but others are also present in southern Europe under Mediterranean-type climates, such as Quercus faginea Lam. We hypothesize the existence of a coordinated functional response at the whole-shoot scale in Q. faginea under Mediterranean conditions to adapt to more xeric habitats. The results reveal a clear morphological and physiological segregation between Q. robur and Q. faginea, which constitute two very contrasting functional types in response to climate dryness. The most outstanding divergence between the two species is the reduction in transpiring area in Q. faginea, which is the main trait imposed by the water deficit in Mediterranean-type climates. The reduction in leaf area ratio in Q. faginea should have a negative effect on carbon gain that is partially counteracted by a higher inherent photosynthetic ability of Q. faginea when compared with Q. robur, as a consequence of higher mesophyll conductance, higher maximum velocity of carboxylation and much higher stomatal conductance (gs). The extremely high gs of Q. faginea counteracts the expected reduction in gs imposed by the stomatal sensitivity to vapor pressure deficit, allowing this species to diminish water losses maintaining high net CO2 assimilation values along the vegetative period under nonlimiting soil water potential values. In conclusion, the present study demonstrates that Q. faginea can be regarded as an example of adaptation of a deciduous oak to Mediterranean-type climates. PMID:26496958

  8. New species in the Sitalcina sura species group (Opiliones, Laniatores, Phalangodidae), with evidence for a biogeographic link between California desert canyons and Arizona sky islands

    PubMed Central

    DiDomenico, Angela; Hedin, Marshal

    2016-01-01

    Abstract The western United States is home to numerous narrowly endemic harvestman taxa (Arachnida, Opiliones), including members of the genus Sitalcina Banks, 1911. Sitalcina is comprised of three species groups, including the monospecific Sitalcina californica and Sitalcina lobata groups, and the Sitalcina sura group with eight described species. All species in the Sitalcina sura group have very small geographic distributions, with group members distributed like disjunct “beads on a string” from Monterey south to southern California and southeast to the sky-island mountain ranges of southern Arizona. Here, molecular phylogenetic and species delimitation analyses were conducted for all described species in the Sitalcina sura group, plus several newly discovered populations. Species trees were reconstructed using multispecies coalescent methods implemented in *BEAST, and species delimitation was accomplished using Bayes Factor Delimitation (BFD). Based on quantitative species delimitation results supported by consideration of morphological characters, two new species (Sitalcina oasiensis sp. n., Sitalcina ubicki sp. n.) are described. We also provide a description of the previously unknown male of Sitalcina borregoensis Briggs, 1968. Molecular phylogenetic evidence strongly supports distinctive desert versus coastal clades, with desert canyon taxa from southern California more closely related to Arizona taxa than to geographically proximate California coastal taxa. We hypothesize that southern ancestry and plate tectonics have played a role in the diversification history of this animal lineage, similar to sclerophyllous plant taxa of the Madro-Tertiary Geoflora. Molecular clock analyses for the Sitalcina sura group are generally consistent with these hypotheses. We also propose that additional Sitalcina species await discovery in the desert canyons of southern California and northern Baja, and the mountains of northwestern mainland Mexico. PMID:27199607

  9. New species in the Sitalcina sura species group (Opiliones, Laniatores, Phalangodidae), with evidence for a biogeographic link between California desert canyons and Arizona sky islands.

    PubMed

    DiDomenico, Angela; Hedin, Marshal

    2016-01-01

    The western United States is home to numerous narrowly endemic harvestman taxa (Arachnida, Opiliones), including members of the genus Sitalcina Banks, 1911. Sitalcina is comprised of three species groups, including the monospecific Sitalcina californica and Sitalcina lobata groups, and the Sitalcina sura group with eight described species. All species in the Sitalcina sura group have very small geographic distributions, with group members distributed like disjunct "beads on a string" from Monterey south to southern California and southeast to the sky-island mountain ranges of southern Arizona. Here, molecular phylogenetic and species delimitation analyses were conducted for all described species in the Sitalcina sura group, plus several newly discovered populations. Species trees were reconstructed using multispecies coalescent methods implemented in *BEAST, and species delimitation was accomplished using Bayes Factor Delimitation (BFD). Based on quantitative species delimitation results supported by consideration of morphological characters, two new species (Sitalcina oasiensis sp. n., Sitalcina ubicki sp. n.) are described. We also provide a description of the previously unknown male of Sitalcina borregoensis Briggs, 1968. Molecular phylogenetic evidence strongly supports distinctive desert versus coastal clades, with desert canyon taxa from southern California more closely related to Arizona taxa than to geographically proximate California coastal taxa. We hypothesize that southern ancestry and plate tectonics have played a role in the diversification history of this animal lineage, similar to sclerophyllous plant taxa of the Madro-Tertiary Geoflora. Molecular clock analyses for the Sitalcina sura group are generally consistent with these hypotheses. We also propose that additional Sitalcina species await discovery in the desert canyons of southern California and northern Baja, and the mountains of northwestern mainland Mexico. PMID:27199607

  10. Effect of controlled inoculation with specific mycorrhizal fungi from the urban environment on growth and physiology of containerized shade tree species growing under different water regimes.

    PubMed

    Fini, Alessio; Frangi, Piero; Amoroso, Gabriele; Piatti, Riccardo; Faoro, Marco; Bellasio, Chandra; Ferrini, Francesco

    2011-11-01

    The aim of this work was to evaluate the effects of selected mycorrhiza obtained in the urban environment on growth, leaf gas exchange, and drought tolerance of containerized plants growing in the nursery. Two-year-old uniform Acer campestre L., Tilia cordata Mill., and Quercus robur L. were inoculated with a mixture of infected roots and mycelium of selected arbuscular (maple, linden) and/or ectomycorrhiza (linden, oak) fungi and grown in well-watered or water shortage conditions. Plant biomass and leaf area were measured 1 and 2 years after inoculation. Leaf gas exchange, chlorophyll fluorescence, and water relations were measured during the first and second growing seasons after inoculation. Our data suggest that the mycelium-based inoculum used in this experiment was able to colonize the roots of the tree species growing in the nursery. Plant biomass was affected by water shortage, but not by inoculation. Leaf area was affected by water regime and, in oak and linden, by inoculation. Leaf gas exchange was affected by inoculation and water stress. V(cmax) and J(max) were increased by inoculation and decreased by water shortage in all species. F(v)/F(m) was also generally higher in inoculated plants than in control. Changes in PSII photochemistry and photosynthesis may be related to the capacity of inoculated plants to maintain less negative leaf water potential under drought conditions. The overall data suggest that inoculated plants were better able to maintain physiological activity during water stress in comparison to non-inoculated plants. PMID:21472449

  11. A physiologically based toxicokinetic and toxicodynamic model links the tissue distribution of benzo[a]pyrene and toxic effects in the scallop Chlamys farreri.

    PubMed

    Liu, Dong; Pan, Luqing; Yang, Huizan; Wang, Jing

    2014-03-01

    A physiologically based toxicokinetic and toxicodynamic (PBTK-TD) model was developed for benzo[a]pyrene (B[a]P) in scallop Chlamys farreri. The PBTK model structure consisted of gill, digestive gland, adductor muscle, hemolymph and other tissues. In TD modeling, aryl hydrocarbon hydroxylase (AHH) activity assay, comet assay, protein carbonyl measurement and lipid peroxidation level determination in digestive gland were used as biomarkers to reflect toxic effects. We integrated B[a]P concentration and biomarkers by using sigmoid Emax model in digestive gland. The PBTK-TD model predicted the B[a]P concentrations within each organ compartment and the toxic effects in digestive gland. The results showed that the predicted and measured data in different organs were in good agreement and comet assay was considered as the best biomarker. This model would serve as a useful tool for pollution monitoring and food security. PMID:24561533

  12. Flow regime in a restored wetland determines trophic links and species composition in the aquatic macroinvertebrate community.

    PubMed

    González-Ortegón, E; Walton, M E M; Moghaddam, B; Vilas, C; Prieto, A; Kennedy, H A; Pedro Cañavate, J; Le Vay, L

    2015-01-15

    In a restored wetland (South of Spain), where different flow regimes control water exchange with the adjacent Guadalquivir estuary, the native Palaemon varians coexists with an exotic counterpart species Palaemon macrodactylus. This controlled m\\acrocosm offers an excellent opportunity to investigate how the effects of water management, through different flow regimes, and the presence of a non-native species affect the aquatic community and the trophic niche (by gut contents and C-N isotopic composition) of the native shrimp Palaemon varians. We found that increased water exchange rate (5% day(-1) in mixed ponds vs. 0.1% day(-1) in extensive ponds) modified the aquatic community of this wetland; while extensive ponds are dominated by isopods and amphipods with low presence of P. macrodactylus, mixed ponds presented high biomass of mysids, corixids, copepods and both shrimp species. An estuarine origin of nutrients and primary production might explain seasonal and spatial differences found among ponds of this wetland. A combined analysis of gut contents and isotopic composition of the native and the exotic species showed that: (1) native P. varians is mainly omnivorous (2) while the non-native P. macrodactylus is more zooplanktivorous and (3) a dietary overlap occurred when both species coexist at mixed ponds where a higher water exchange and high abundance of mysids and copepods diversifies the native species' diet. Thus differences in the trophic ecology of both species are clearly explained by water management. This experimental study is a valuable tool for integrated management between river basin and wetlands since it allows quantification of wetland community changes in response to the flow regime. PMID:25242150

  13. Variations in diatom communities at genus and species levels in peatlands (central China) linked to microhabitats and environmental factors.

    PubMed

    Chen, Xu; Bu, Zhaojun; Stevenson, Mark A; Cao, Yanmin; Zeng, Linghan; Qin, Bo

    2016-10-15

    Peatlands are a specialized type of organic wetlands, fulfilling essential roles as global carbon sinks, headwaters of rivers and biodiversity hotspots. Despite their importance, peatlands are being lost at an alarming rate due to human disturbance and climatic variability. Both the scientific and regulatory communities have focused considerable attention on developing tools for assessing environmental changes in peatlands. Diatoms are widely used in biomonitoring studies of lakes, rivers and streams as they have high abundance, specific ecological preferences and can respond rapidly to environmental change. However, diatom-based assessment studies in peatlands remain limited. The aims of this study were to identify indicator species and genus for three types of habitats (hummocks, hollows and ditch edges) in peatlands (central China), to examine the effects of physiochemical factors on diatom composition at genus and species levels, and to compare the efficiency of species- and genus-level identification in environmental assessment. Our results revealed that hummocks were characterized by drought-tolerant diatoms, while hollows were dominated by species and genus preferring wet conditions. Ditch edges were characterized by diatoms with different life strategies. Depth to water table, redox potential, conductivity and calcium were significant predictors of both genus- and species-level composition. According to ordination analyses, pH was not correlated with species composition while it was a significant factor associated with genus-level composition. Genus-level composition outperformed species composition in describing the response of diatoms to environmental variables. Our results indicate that diatoms can be useful environmental indicators of peatlands, and show that genus-level taxonomic analysis can be a potential tool for assessing environmental change in peatlands. PMID:27289395

  14. Local site variation in stopover physiology of migrating songbirds near the south shore of Lake Ontario is linked to fruit availability and quality

    PubMed Central

    Smith, Susan B.; Miller, Allyson C.; Merchant, Charmaine R.; Sankoh, Amie F.

    2015-01-01

    Birds that migrate long distances between breeding and wintering grounds are challenged to find adequate stopover sites that can provide a high-quality source of nutrition in order to refuel quickly and continue on their migratory journeys. Wild fruits are a well-documented component in the diets of many passerines during autumn migration. Thus, fruit availability and the proliferation of shrubs that bear low-quality fruits at important stopover sites may dictate the quality of food resources available for refuelling birds and present a conservation concern. We profiled plasma metabolites of two migratory passerine species at two different stopover sites near the south shore of Lake Ontario during the peak of autumn migration. We also measured diversity, availability and nutritional quality of fruits present at these sites. Site explained most of the variation in plasma triglyceride for both bird species, but was less important than other confounding variables for explaining concentrations of plasma β-hydroxybutyrate and plasma uric acid concentrations. Site differences in fat deposition, as indicated by plasma triglyceride, may in part be explained by the large differences in diversity and availability of high-quality fruits between the two sites. Our results suggest that abundant, lipid-rich native fruits with high-energy density are associated with increased fat deposition during autumn stopovers for some species, although other factors, such as proximity to the Lake Ontario shoreline and the opportunities to refuel in the surrounding landscape, are likely to play a role in stopover site use by birds. It is possible that local site characteristics that influence growing conditions may impact the quality of fruits produced by a plant species, altering the availability of critical nutrients for avian consumers. PMID:27293721

  15. Physiological responses of emerald ash borer larvae to feeding on different ash species reveal putative resistance mechanisms and insect counter-adaptations.

    PubMed

    Rigsby, C M; Showalter, D N; Herms, D A; Koch, J L; Bonello, P; Cipollini, D

    2015-07-01

    Emerald ash borer, Agrilus planipennis Fairmaire, an Asian wood-boring beetle, has devastated ash (Fraxinus spp.) trees in North American forests and landscapes since its discovery there in 2002. In this study, we collected living larvae from EAB-resistant Manchurian ash (Fraxinus mandschurica), and susceptible white (Fraxinus americana) and green (Fraxinus pennsylvanica) ash hosts, and quantified the activity and production of selected detoxification, digestive, and antioxidant enzymes. We hypothesized that differences in larval physiology could be used to infer resistance mechanisms of ash. We found no differences in cytochrome P450, glutathione-S-transferase, carboxylesterase, sulfotransferase, and tryptic BApNAase activities between larvae feeding on different hosts. Despite this, Manchurian ash-fed larvae produced a single isozyme of low electrophoretic mobility that was not produced in white or green ash-fed larvae. Additionally, larvae feeding on white and green ash produced two serine protease isozymes of high electrophoretic mobility that were not observed in Manchurian ash-fed larvae. We also found lower activity of β-glucosidase and higher activities of monoamine oxidase, ortho-quinone reductase, catalase, superoxide dismutase, and glutathione reductase in Manchurian ash-fed larvae compared to larvae that had fed on susceptible ash. A single isozyme was detected for both catalase and superoxide dismutase in all larval groups. The activities of the quinone-protective and antioxidant enzymes are consistent with the resistance phenotype of the host species, with the highest activities measured in larvae feeding on resistant Manchurian ash. We conclude that larvae feeding on Manchurian ash could be under quinone and oxidative stress, suggesting these may be potential mechanisms of resistance of Manchurian ash to EAB larvae, and that quinone-protective and antioxidant enzymes are important counter-adaptations of larvae for dealing with these resistance

  16. Global Climate Change Effects on Venezuela's Vulnerability to Chagas Disease is Linked to the Geographic Distribution of Five Triatomine Species.

    PubMed

    Ceccarelli, Soledad; Rabinovich, Jorge E

    2015-11-01

    We analyzed the possible effects of global climate change on the potential geographic distribution in Venezuela of five species of triatomines (Eratyrus mucronatus (Stal, 1859), Panstrongylus geniculatus (Latreille, 1811), Rhodnius prolixus (Stål, 1859), Rhodnius robustus (Larrousse, 1927), and Triatoma maculata (Erichson, 1848)), vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. To obtain the future potential geographic distributions, expressed as climatic niche suitability, we modeled the presences of these species using two IPCC (Intergovernmental Panel on Climate Change) future emission scenarios of global climate change (A1B and B1), the Global Climate model CSIRO Mark 3.0, and three periods of future projections (years 2020, 2060, and 2080). After estimating with the MaxEnt software the future climatic niche suitability for each species, scenario, and period of future projections, we estimated a series of indexes of Venezuela's vulnerability at the county, state, and country level, measured as the number of people exposed due to the changes in the geographical distribution of the five triatomine species analyzed. Despite that this is not a measure of the risk of Chagas disease transmission, we conclude that possible future effects of global climate change on the Venezuelan population vulnerability show a slightly decreasing trend, even taking into account future population growth; we can expect fewer locations in Venezuela where an average Venezuelan citizen would be exposed to triatomines in the next 50-70 yr. PMID:26336258

  17. Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex

    PubMed Central

    Negård, Mariell; Uhlig, Silvio; Kauserud, Håvard; Andersen, Tom; Høiland, Klaus; Vrålstad, Trude

    2015-01-01

    The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability. PMID:25928134

  18. Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex.

    PubMed

    Negård, Mariell; Uhlig, Silvio; Kauserud, Håvard; Andersen, Tom; Høiland, Klaus; Vrålstad, Trude

    2015-05-01

    The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability. PMID:25928134

  19. Links between Belowground and Aboveground Resource-Related Traits Reveal Species Growth Strategies that Promote Invasive Advantages

    PubMed Central

    Smith, Maria S.; Fridley, Jason D.; Goebel, Marc; Bauerle, Taryn L.

    2014-01-01

    Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited. PMID:25105975

  20. Phylogeographic Evidence for a Link of Species Divergence of Ephedra in the Qinghai-Tibetan Plateau and Adjacent Regions to the Miocene Asian Aridification

    PubMed Central

    Qin, Ai-Li; Wang, Ming-Ming; Cun, Yu-Zhi; Yang, Fu-Sheng; Wang, Shan-Shan; Ran, Jin-Hua; Wang, Xiao-Quan

    2013-01-01

    The Qinghai-Tibetan Plateau (QTP) has become one of the hotspots for phylogeographical studies due to its high species diversity. However, most previous studies have focused on the effects of the Quaternary glaciations on phylogeographical structures and the locations of glacial refugia, and little is known about the effects of the aridization of interior Asia on plant population structure and speciation. Here the chloroplast DNA (cpDNA) trnT-trnF and trnS-trnfM sequences were used to investigate the differentiation and phylogeographical history of 14 Ephedra species from the QTP and northern China, based on a sampling of 107 populations. The phylogeographical analysis, together with phylogenetic reconstruction based on combined four cpDNA fragments (rbcL, rpl16, rps4, and trnS-trnfM), supports three main lineages (eastern QTP, southern QTP, and northern China) of these Ephedra species. Divergence of each lineage could be dated to the Middle or Late Miocene, and was very likely linked to the uplift of the QTP and the Asian aridification, given the high drought and/or cold tolerance of Ephedra. Most of the Ephedra species had low intraspecific variation and lacked a strong phylogeographical structure, which could be partially attributed to clonal reproduction and a relatively recent origin. In addition, ten of the detected 25 cpDNA haplotypes are shared among species, suggesting that a wide sampling of species is helpful to investigate the origin of observed haplotypes and make reliable phylogeographical inference. Moreover, the systematic positions of some Ephedra species are discussed. PMID:23418542

  1. Physiology in conservation translocations

    PubMed Central

    Tarszisz, Esther; Dickman, Christopher R.; Munn, Adam J.

    2014-01-01

    Conservation translocations aim to restore species to their indigenous ranges, protect populations from threats and/or reinstate ecosystem functions. They are particularly important for the conservation and management of rare and threatened species. Despite tremendous efforts and advancement in recent years, animal conservation translocations generally have variable success, and the reasons for this are often uncertain. We suggest that when little is known about the physiology and wellbeing of individuals either before or after release, it will be difficult to determine their likelihood of survival, and this could limit advancements in the science of translocations for conservation. In this regard, we argue that physiology offers novel approaches that could substantially improve translocations and associated practices. As a discipline, it is apparent that physiology may be undervalued, perhaps because of the invasive nature of some physiological measurement techniques (e.g. sampling body fluids, surgical implantation). We examined 232 publications that dealt with translocations of terrestrial vertebrates and aquatic mammals and, defining ‘success’ as high or low, determined how many of these studies explicitly incorporated physiological aspects into their protocols and monitoring. From this review, it is apparent that physiological evaluation before and after animal releases could progress and improve translocation/reintroduction successes. We propose a suite of physiological measures, in addition to animal health indices, for assisting conservation translocations over the short term and also for longer term post-release monitoring. Perhaps most importantly, we argue that the incorporation of physiological assessments of animals at all stages of translocation can have important welfare implications by helping to reduce the total number of animals used. Physiological indicators can also help to refine conservation translocation methods. These approaches fall

  2. Contrasting evolutionary patterns of spore coat proteins in two Bacillus species groups are linked to a difference in cellular structure

    PubMed Central

    2013-01-01

    Background The Bacillus subtilis-group and the Bacillus cereus-group are two well-studied groups of species in the genus Bacillus. Bacteria in this genus can produce a highly resistant cell type, the spore, which is encased in a complex protective protein shell called the coat. Spores in the B. cereus-group contain an additional outer layer, the exosporium, which encircles the coat. The coat in B. subtilis spores possesses inner and outer layers. The aim of this study is to investigate whether differences in the spore structures influenced the divergence of the coat protein genes during the evolution of these two Bacillus species groups. Results We designed and implemented a computational framework to compare the evolutionary histories of coat proteins. We curated a list of B. subtilis coat proteins and identified their orthologs in 11 Bacillus species based on phylogenetic congruence. Phylogenetic profiles of these coat proteins show that they can be divided into conserved and labile ones. Coat proteins comprising the B. subtilis inner coat are significantly more conserved than those comprising the outer coat. We then performed genome-wide comparisons of the nonsynonymous/synonymous substitution rate ratio, dN/dS, and found contrasting patterns: Coat proteins have significantly higher dN/dS in the B. subtilis-group genomes, but not in the B. cereus-group genomes. We further corroborated this contrast by examining changes of dN/dS within gene trees, and found that some coat protein gene trees have significantly different dN/dS between the B subtilis-clade and the B. cereus-clade. Conclusions Coat proteins in the B. subtilis- and B. cereus-group species are under contrasting selective pressures. We speculate that the absence of the exosporium in the B. subtilis spore coat effectively lifted a structural constraint that has led to relaxed negative selection pressure on the outer coat. PMID:24283940

  3. Reactive Oxygen Species (ROS) Inducible DNA Cross-Linking Agents and Their Effect on Cancer Cells and Normal Lymphocytes

    PubMed Central

    2015-01-01

    Reducing host toxicity is one of the main challenges of cancer chemotherapy. Many tumor cells contain high levels of ROS that make them distinctively different from normal cells. We report a series of ROS-activated aromatic nitrogen mustards that selectively kill chronic lymphocytic leukemia (CLL) over normal lymphocytes. These agents showed powerful DNA cross-linking abilities when coupled with H2O2, one of the most common ROS in cancer cells, whereas little DNA cross-linking was detected without H2O2. Consistent with chemistry observation, in vitro cytotoxicity assay demonstrated that these agents induced 40–80% apoptosis in primary leukemic lymphocytes isolated from CLL patients but less than 25% cell death to normal lymphocytes from healthy donors. The IC50 for the most potent compound (2) was ∼5 μM in CLL cells, while the IC50 was not achieved in normal lymphocytes. Collectively, these data provide utility and selectivity of these agents that will inspire further and effective applications. PMID:24801734

  4. Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay.

    PubMed

    Nkouawa, Agathe; Sako, Yasuhito; Okamoto, Munehiro; Ito, Akira

    2016-06-01

    For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T. solium, T. saginata, and T. asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical. PMID:27044566

  5. Exploring mechanisms linked to differentiation and function of dimorphic chloroplasts in the single cell C4 species Bienertia sinuspersici

    PubMed Central

    2014-01-01

    Background In the model single-cell C4 plant Bienertia sinuspersici, chloroplast- and nuclear-encoded photosynthetic enzymes, characteristically confined to either bundle sheath or mesophyll cells in Kranz-type C4 leaves, all occur together within individual leaf chlorenchyma cells. Intracellular separation of dimorphic chloroplasts and key enzymes within central and peripheral compartments allow for C4 carbon fixation analogous to NAD-malic enzyme (NAD-ME) Kranz type species. Several methods were used to investigate dimorphic chloroplast differentiation in B. sinuspersici. Results Confocal analysis revealed that Rubisco-containing chloroplasts in the central compartment chloroplasts (CCC) contained more photosystem II proteins than the peripheral compartment chloroplasts (PCC) which contain pyruvate,Pi dikinase (PPDK), a pattern analogous to the cell type-specific chloroplasts of many Kranz type NAD-ME species. Transient expression analysis using GFP fusion constructs containing various lengths of a B. sinuspersici Rubisco small subunit (RbcS) gene and the transit peptide of PPDK revealed that their import was not specific to either chloroplast type. Immunolocalization showed the rbcL-specific mRNA binding protein RLSB to be selectively localized to the CCC in B. sinuspersici, and to Rubisco-containing BS chloroplasts in the closely related Kranz species Suaeda taxifolia. Comparative fluorescence analyses were made using redox-sensitive and insensitive GFP forms, as well comparative staining using the peroxidase indicator 3,3-diaminobenzidine (DAB), which demonstrated differences in stromal redox potential, with the CCC having a more negative potential than the PCC. Conclusions Both CCC RLSB localization and the differential chloroplast redox state are suggested to have a role in post-transcriptional rbcL expression. PMID:24443986

  6. Physiological Waterfalls

    ERIC Educational Resources Information Center

    Leith, David E.

    1976-01-01

    Provides background information, defining areas within organ systems where physiological waterfalls exist. Describes pressure-flow relationships of elastic tubes (blood vessels, airways, renal tubules, various ducts). (CS)

  7. Cytonuclear theory for haplodiploid species and X-linked genes. I. Hardy-Weinberg dynamics and continent-island, hybrid zone models.

    PubMed

    Goodisman, M A; Asmussen, M A

    1997-09-01

    We develop models that describe the cytonuclear structure for either a cytoplasmic and nuclear marker in a haplodiploid species or a cytoplasmic and X-linked marker in a diploid species. Sex-specific disequilibrium statistics that summarize nonrandom cytonuclear associations in such systems are defined, and their basic Hardy-Weinberg dynamics and admixture formulae are delimited. We focus on the context of hybrid zones and develop continent-island models whereby individuals from two genetically differentiated source populations migrate into and mate within a single zone of admixture. We examine the effects of differential migration of the sexes, assortative mating by pure type females, and census time (relative to mating and migration), as well as special cases of random mating and migration subsumed under the general models. We show that pure type individuals and nonzero cytonuclear disequilibria can be maintained within a hybrid zone if there is continued migration from both source populations, and that females generally have a greater influence over these cytonuclear variables than males. The resulting theoretical framework can be used to estimate the rates of assortative mating and sex-specific gene flow in hybrid zones and other zones of admixture involving haplodiploid or sex-linked cytonuclear data. PMID:9286692

  8. Linking the Response of Annual Grasslands to Warming and Altered Rainfall Across Scales of Gene Expression, Species, and Ecosystem

    NASA Astrophysics Data System (ADS)

    Torn, M. S.; Bernard, S. M.; Castanha, C.; Fischer, M. L.; Hopkins, F. M.; Placella, S. A.; St. Clair, S. B.; Salve, R.; Sudderth, E.; Herman, D.; Ackerly, D.; Firestone, M. K.

    2007-12-01

    Climate change can influence terrestrial ecosystems at multiple biological levels: gene expression, species, and ecosystem. We are studying California grassland mesocosms with seven annual species (five grasses, two forbs) that were started in 2005. In the 2006-2007 growing season, they were exposed to three rainfall treatments (297, 552, and 867 mm y-1) and soil and air temperature (ambient and elevated +4oC) in replicated greenhouses. This presentation will combine plant and ecosystem level results with transcript level analyses associated with key enzymes, such as rubisco and glutamine synthetase (GS). Because rainfall is the dominant climate variable for most processes in this Mediterranean ecosystem, the effect of warming was strongly mediated by rainfall. In fact, we saw significant interactions between temperature and rainfall treatments at all three biological levels. For example, at the ecosystem level, warming led to a decrease in aboveground and total NPP under low rainfall, and an increase under high rainfall. For the dominant species, Avena barbata, warming had no effect under high rainfall, but suppressed Avena NPP in low rainfall. At the same time, warmer, wetter conditions accelerated Avena flowering by almost 15 days. This shift in phenology was presaged by observations at the transcript level. Specifically, in the high temperature, high rainfall treatment, the levels of mRNAs for RbcS and GS2 (encoding the small subunit of rubisco and the chloroplastic isoform of GS, respectively) declined while GS1 (encoding the cytosolic isoform of GS) was upregulated several weeks before heading. The transcript level response (along with soil and plant nitrogen data) indicated the leaf had switched from a carbon and nitrogen sink to a source - consistent with more mature plant function and earlier flowering. Soil CO2 respiration also showed strong rain-by-temperature interactions that were due mainly to changes in root response (respiration and/or exudates

  9. How to link the relative abundances of gas species in coma of comets to their initial chemical composition?

    NASA Astrophysics Data System (ADS)

    Marboeuf, Ulysse; Schmitt, Bernard

    2014-11-01

    Comets are expected to be the most primitive objects in the Solar System. The chemical composition of these objects is frequently assumed to be directly provided by the observations of the abundances of volatile molecules in the coma. The present work aims to determine the relationship between the chemical composition of the coma, the outgassing profile of volatile molecules and the internal chemical composition, and water ice structure of the nucleus, and physical assumptions on comets. To do this, we have developed a quasi 3D model of a cometary nucleus which takes into account all phase changes and water ice structures (amorphous, crystalline, clathrate, and a mixture of them); we have applied this model to the Comet 67P/Churyumov-Gerasimenko, the target of the Rosetta mission. We find that the outgassing profile of volatile molecules is a strong indicator of the physical and thermal properties (water ice structure, thermal inertia, abundances, distribution, physical differentiation) of the solid nucleus. Day/night variations of the rate of production of species helps to distinguish the clathrate structure from other water ice structures in nuclei, implying different thermodynamic conditions of cometary ice formation in the protoplanetary disc. The relative abundance (to H2O) of volatile molecules released from the nucleus interior varies by some orders of magnitude as a function of the distance to the Sun, the volatility of species, their abundance and distribution between the "trapped" and "condensed" states, the structure of water ice, and the thermal inertia and other physical assumptions (dust mantle, …) on the nucleus. For the less volatile molecules such as CO2 and H2S, the relative (to H2O) abundance of species in coma remain similar to the primitive composition of the nucleus (relative deviation less than 25%) only around the perihelion passage (in the range -3 to -2 to +2-3 AU), whatever is the water ice structure and chemical composition, and under

  10. Rowing Physiology.

    ERIC Educational Resources Information Center

    Spinks, W. L.

    This review of the literature discusses and examines the methods used in physiological assessment of rowers, results of such assessments, and future directions emanating from research in the physiology of rowing. The first section discusses the energy demands of rowing, including the contribution of the energy system, anaerobic metabolism, and the…

  11. Movement Patterns for a Critically Endangered Species, the Leatherback Turtle (Dermochelys coriacea), Linked to Foraging Success and Population Status

    PubMed Central

    Bailey, Helen; Fossette, Sabrina; Bograd, Steven J.; Shillinger, George L.; Swithenbank, Alan M.; Georges, Jean-Yves; Gaspar, Philippe; Strömberg, K. H. Patrik; Paladino, Frank V.; Spotila, James R.; Block, Barbara A.; Hays, Graeme C.

    2012-01-01

    Foraging success for pelagic vertebrates may be revealed by horizontal and vertical movement patterns. We show markedly different patterns for leatherback turtles in the North Atlantic versus Eastern Pacific, which feed on gelatinous zooplankton that are only occasionally found in high densities. In the Atlantic, travel speed was characterized by two modes, indicative of high foraging success at low speeds (<15 km d−1) and transit at high speeds (20–45 km d−1). Only a single mode was evident in the Pacific, which occurred at speeds of 21 km d−1 indicative of transit. The mean dive depth was more variable in relation to latitude but closer to the mean annual depth of the thermocline and nutricline for North Atlantic than Eastern Pacific turtles. The most parsimonious explanation for these findings is that Eastern Pacific turtles rarely achieve high foraging success. This is the first support for foraging behaviour differences between populations of this critically endangered species and suggests that longer periods searching for prey may be hindering population recovery in the Pacific while aiding population maintenance in the Atlantic. PMID:22615767

  12. What is the link of the abundances of volatile species in the coma with the ones in the nucleus ?

    NASA Astrophysics Data System (ADS)

    Marboeuf, U.; Schmitt, B.

    2014-04-01

    The chemical composition of comets is frequently assumed to be directly provided by the observations of the abundances of volatile molecules in the coma. The present work aims to determine the relationship between the chemical composition of the coma, the outgassing profile of volatile molecules and the physicochemical composition of the nucleus. To do this, we have developed a quasi 3D model of a cometary nucleus which takes into account all phase changes and water ice structures and applied this model to the comet 67P/Churyumov-Gerasimenko, the target of the Rosetta mission. We find that the outgassing profile of volatile molecules is a strong indicator of the physical and thermal properties of the solid nucleus. The relative abundance (to H2O) of volatile molecules released from the nucleus interior varies by some orders of magnitude as a function of the distance to the sun, the volatility of species, their abundance and distribution between the 'trapped' and 'condensed' states, the structure of water ice, and the thermal inertia and other physical assumptions (dust mantle, ...) on the nucleus.

  13. Early replication dynamics of sex-linked mitochondrial DNAs in the doubly uniparental inheritance species Ruditapes philippinarum (Bivalvia Veneridae).

    PubMed

    Guerra, D; Ghiselli, F; Milani, L; Breton, S; Passamonti, M

    2016-03-01

    Mitochondrial homoplasmy, which is maintained by strictly maternal inheritance and a series of bottlenecks, is thought to be an adaptive condition for metazoans. Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial transmission found in bivalve species, in which two distinct mitochondrial genome (mtDNA) lines are present, one inherited through eggs (F) and one through sperm (M). During development, the two lines segregate in a sex- and tissue-specific manner: females lose M during embryogenesis, whereas males actively segregate it in the germ line. These two pivotal events are still poorly characterized. Here we investigated mtDNA replication dynamics during embryogenesis and pre-adulthood of the venerid Ruditapes philippinarum using real-time quantitative PCR. We found that both mtDNAs do not detectably replicate during early embryogenesis, and that the M line might be lost from females around 24 h of age. A rise in mtDNA copy number was observed before the first reproductive season in both sexes, with the M mitochondrial genome replicating more than the F in males, and we associate these boosts to the early phase of gonad production. As evidence indicates that DUI relies on the same molecular machine of mitochondrial maternal inheritance that is common in most animals, our data are relevant not only to DUI but also to shed light on how differential segregations of mtDNA variants, in the same nuclear background, may be controlled during development. PMID:26626575

  14. COFFEE SEED PHYSIOLOGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are more than 70 species of Coffea (Rubiaceae), but only C. arabica and C. canephora are used commercially. Better understanding of seed physiology within Coffea will facilitate the incorporation of genetic traits for resistance to biotic and abiotic stresses from wild relatives into commerci...

  15. Post-Harvest Physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Numerous plant microbial and physiological processes occur during forage harvest and storage and are almost always deleterious. These processes are influenced by preharvest factors such as mowing time of day, plant species, and maturity stage, as well as by harvest and storage variables. Avoidance o...

  16. The Emergence of Physiology and Form: Natural Selection Revisited

    PubMed Central

    Torday, John S.

    2016-01-01

    Natural Selection describes how species have evolved differentially, but it is descriptive, non-mechanistic. What mechanisms does Nature use to accomplish this feat? One known way in which ancient natural forces affect development, phylogeny and physiology is through gravitational effects that have evolved as mechanotransduction, seen in the lung, kidney and bone, linking as molecular homologies to skin and brain. Tracing the ontogenetic and phylogenetic changes that have facilitated mechanotransduction identifies specific homologous cell-types and functional molecular markers for lung homeostasis that reveal how and why complex physiologic traits have evolved from the unicellular to the multicellular state. Such data are reinforced by their reverse-evolutionary patterns in chronic degenerative diseases. The physiologic responses of model organisms like Dictyostelium and yeast to gravity provide deep comparative molecular phenotypic homologies, revealing mammalian Target of Rapamycin (mTOR) as the final common pathway for vertical integration of vertebrate physiologic evolution; mTOR integrates calcium/lipid epistatic balance as both the proximate and ultimate positive selection pressure for vertebrate physiologic evolution. The commonality of all vertebrate structure-function relationships can be reduced to calcium/lipid homeostatic regulation as the fractal unit of vertebrate physiology, demonstrating the primacy of the unicellular state as the fundament of physiologic evolution. PMID:27534726

  17. The Emergence of Physiology and Form: Natural Selection Revisited.

    PubMed

    Torday, John S

    2016-01-01

    Natural Selection describes how species have evolved differentially, but it is descriptive, non-mechanistic. What mechanisms does Nature use to accomplish this feat? One known way in which ancient natural forces affect development, phylogeny and physiology is through gravitational effects that have evolved as mechanotransduction, seen in the lung, kidney and bone, linking as molecular homologies to skin and brain. Tracing the ontogenetic and phylogenetic changes that have facilitated mechanotransduction identifies specific homologous cell-types and functional molecular markers for lung homeostasis that reveal how and why complex physiologic traits have evolved from the unicellular to the multicellular state. Such data are reinforced by their reverse-evolutionary patterns in chronic degenerative diseases. The physiologic responses of model organisms like Dictyostelium and yeast to gravity provide deep comparative molecular phenotypic homologies, revealing mammalian Target of Rapamycin (mTOR) as the final common pathway for vertical integration of vertebrate physiologic evolution; mTOR integrates calcium/lipid epistatic balance as both the proximate and ultimate positive selection pressure for vertebrate physiologic evolution. The commonality of all vertebrate structure-function relationships can be reduced to calcium/lipid homeostatic regulation as the fractal unit of vertebrate physiology, demonstrating the primacy of the unicellular state as the fundament of physiologic evolution. PMID:27534726

  18. Anatomy & Physiology

    MedlinePlus

    ... Central Nervous System Peripheral Nervous System Review Quiz Endocrine System Characteristics of Hormones Endocrine Glands & Their Hormones Pituitary & ... Thyroid & Parathyroid Glands Adrenal Gland Pancreas Gonads Other Endocrine Glands ... Cardiovascular System Heart Structure of the Heart Physiology of the ...

  19. Genome size differences in Hyalella cryptic species.

    PubMed

    Vergilino, Roland; Dionne, Kaven; Nozais, Christian; Dufresne, France; Belzile, Claude

    2012-02-01

    The Hyalella azteca (Saussure) complex includes numerous amphipod cryptic species in freshwater habitats in America as revealed by DNA barcoding surveys. Two ecomorphs (small and large) have evolved numerous times in this complex. Few phenotypic criteria have been found to differentiate between the numerous species of this complex. The present study aims to explore genome size differences between some species of the H. azteca complex co-occurring in a Canadian boreal lake using flow cytometry. Nuclear DNA content was estimated for 50 individuals belonging to six COI haplotypes corresponding to four provisional species of the H. azteca complex. Species from the large ecomorph had C-values significantly larger than species from the small ecomorph, whereas slight differences were found among species of the small ecomorph. These differences in genome sizes might be linked to ecological and physiological differences among species of the H. azteca complex. PMID:22263854

  20. Linking land cover and species distribution models to project potential ranges of malaria vectors: an example using Anopheles arabiensis in Sudan and Upper Egypt

    PubMed Central

    2012-01-01

    Background Anopheles arabiensis is a particularly opportunistic feeder and efficient vector of Plasmodium falciparum in Africa and may invade areas outside its normal range, including areas separated by expanses of barren desert. The purpose of this paper is to demonstrate how spatial models can project future irrigated cropland and potential, new suitable habitat for vectors such as An. arabiensis. Methods Two different but complementary spatial models were linked to demonstrate their synergy for assessing re-invasion potential of An. arabiensis into Upper Egypt as a function of irrigated cropland expansion by 2050. The first model (The Land Change Modeler) was used to simulate changes in irrigated cropland using a Markov Chain approach, while the second model (MaxEnt) uses species occurrence points, land cover and other environmental layers to project probability of species presence. Two basic change scenarios were analysed, one involving a more conservative business-as-usual (BAU) assumption and second with a high probability of desert-to-cropland transition (Green Nile) to assess a broad range of potential outcomes by 2050. Results The results reveal a difference of 82,000 sq km in potential An. arabiensis range between the BAU and Green Nile scenarios. The BAU scenario revealed a highly fragmented set of small, potential habitat patches separated by relatively large distances (maximum distance = 64.02 km, mean = 12.72 km, SD = 9.92), while the Green Nile scenario produced a landscape characterized by large patches separated by relatively shorter gaps (maximum distance = 49.38, km, mean = 4.51 km, SD = 7.89) that may be bridged by the vector. Conclusions This study provides a first demonstration of how land change and species distribution models may be linked to project potential changes in vector habitat distribution and invasion potential. While gaps between potential habitat patches remained large in the Green Nile scenario, the

  1. Avian reproductive physiology

    USGS Publications Warehouse

    Gee, G.F.

    1995-01-01

    Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

  2. Physiological and isotopic (delta(13)C and delta(18)O) responses of three tropical tree species to water and nutrient availability.

    PubMed

    Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

    2009-10-01

    Water-use efficiency and stable isotope composition were studied in three tropical tree species. Seedlings of Tectona grandis, Swietenia macrophylla and Platymiscium pinnatum were grown at either high or low water supply, and with or without added fertilizer. These three species previously exhibited low, intermediate and high whole-plant water-use efficiency (TE) when grown at high water supply in unfertilized soil. Responses of TE to water and nutrient availability varied among species. The TE was calculated as experiment-long dry matter production divided by cumulative water use. Species-specific offsets were observed in relationships between TE and whole-plant (13)C discrimination (Delta(13)C(p)). These offsets could be attributed to a breakdown in the relationship between Delta(13)C(p) and the ratio of intercellular to ambient CO(2) partial pressures (c(i)/c(a)) in P. pinnatum, and to variation among species in the leaf-to-air vapour pressure difference (v). Thus, a plot of v.TE against c(i)/c(a) showed a general relationship among species. Relationships between delta(18)O of stem dry matter and stomatal conductance ranged from strongly negative for S. macrophylla to no relationship for T. grandis. Results suggest inter-specific variation among tropical tree species in relationships between stable isotope ratios (delta(13)C and delta(18)O) and the gas exchange processes thought to affect them. PMID:19558409

  3. Regulatory Physiology

    NASA Technical Reports Server (NTRS)

    Lane, Helen W.; Whitson, Peggy A.; Putcha, Lakshmi; Baker, Ellen; Smith, Scott M.; Stewart, Karen; Gretebeck, Randall; Nimmagudda, R. R.; Schoeller, Dale A.; Davis-Street, Janis

    1999-01-01

    As noted elsewhere in this report, a central goal of the Extended Duration Orbiter Medical Project (EDOMP) was to ensure that cardiovascular and muscle function were adequate to perform an emergency egress after 16 days of spaceflight. The goals of the Regulatory Physiology component of the EDOMP were to identify and subsequently ameliorate those biochemical and nutritional factors that deplete physiological reserves or increase risk for disease, and to facilitate the development of effective muscle, exercise, and cardiovascular countermeasures. The component investigations designed to meet these goals focused on biochemical and physiological aspects of nutrition and metabolism, the risk of renal (kidney) stone formation, gastrointestinal function, and sleep in space. Investigations involved both ground-based protocols to validate proposed methods and flight studies to test those methods. Two hardware tests were also completed.

  4. Physiological breeding.

    PubMed

    Reynolds, Matthew; Langridge, Peter

    2016-06-01

    Physiological breeding crosses parents with different complex but complementary traits to achieve cumulative gene action for yield, while selecting progeny using remote sensing, possibly in combination with genomic selection. Physiological approaches have already demonstrated significant genetic gains in Australia and several developing countries of the International Wheat Improvement Network. The techniques involved (see Graphical Abstract) also provide platforms for research and refinement of breeding methodologies. Recent examples of these include screening genetic resources for novel expression of Calvin cycle enzymes, identification of common genetic bases for heat and drought adaptation, and genetic dissection of trade-offs among yield components. Such information, combined with results from physiological crosses designed to test novel trait combinations, lead to more precise breeding strategies, and feed models of genotype-by-environment interaction to help build new plant types and experimental environments for future climates. PMID:27161822

  5. Neuropeptide physiology in helminths.

    PubMed

    Mousley, Angela; Novozhilova, Ekaterina; Kimber, Michael J; Day, Tim A

    2010-01-01

    Parasitic worms come from two distinct, distant phyla, Nematoda (roundworms) and Platyhelminthes (flatworms). The nervous systems of worms from both phyla are replete with neuropeptides and there is ample physiological evidence that these neuropeptides control vital aspects of worm biology. In each phyla, the physiological evidence for critical roles for helminth neuropeptides is derived from both parasitic and free-living members. In the nematodes, the intestinal parasite Ascaris suum and the free-living Caenorhabditis elegans have yielded most of the data; in the platyhelminths, the most physiological data has come from the blood fluke Schistosoma mansoni. FMRFamide-like peptides (FLPs) have many varied effects (excitation, relaxation, or a combination) on somatic musculature, reproductive musculature, the pharynx and motor neurons in nematodes. Insulin-like peptides (INSs) play an essential role in nematode dauer formation and other developmental processes. There is also some evidence for a role in somatic muscle control for the somewhat heterogeneous grouping ofpeptides known as neuropeptide-like proteins (NLPs). In platyhelminths, as in nematodes, FLPs have a central role in somatic muscle function. Reports of FLP physiological action in platyhelminths are limited to a potent excitation of the somatic musculature. Platyhelminths are also abundantly endowed with neuropeptide Fs (NPFs), which appear absent from nematodes. There is not yet any data linking platyhelminth NPF to any particular physiological outcome, but this neuropeptide does potently and specifically inhibit cAMP accumulation in schistosomes. In nematodes and platyhelminths, there is an abundance of physiological evidence demonstrating that neuropeptides play critical roles in the biology of both free-living and parasitic helminths. While it is certainly true that there remains a great deal to learn about the biology of neuropeptides in both phyla, physiological evidence presently available points

  6. Are cranial biomechanical simulation data linked to known diets in extant taxa? A method for applying diet-biomechanics linkage models to infer feeding capability of extinct species.

    PubMed

    Tseng, Zhijie Jack; Flynn, John J

    2015-01-01

    Performance of the masticatory system directly influences feeding and survival, so adaptive hypotheses often are proposed to explain craniodental evolution via functional morphology changes. However, the prevalence of "many-to-one" association of cranial forms and functions in vertebrates suggests a complex interplay of ecological and evolutionary histories, resulting in redundant morphology-diet linkages. Here we examine the link between cranial biomechanical properties for taxa with different dietary preferences in crown clade Carnivora, the most diverse clade of carnivorous mammals. We test whether hypercarnivores and generalists can be distinguished based on cranial mechanical simulation models, and how such diet-biomechanics linkages relate to morphology. Comparative finite element and geometric morphometrics analyses document that predicted bite force is positively allometric relative to skull strain energy; this is achieved in part by increased stiffness in larger skull models and shape changes that resist deformation and displacement. Size-standardized strain energy levels do not reflect feeding preferences; instead, caniform models have higher strain energy than feliform models. This caniform-feliform split is reinforced by a sensitivity analysis using published models for six additional taxa. Nevertheless, combined bite force-strain energy curves distinguish hypercarnivorous versus generalist feeders. These findings indicate that the link between cranial biomechanical properties and carnivoran feeding preference can be clearly defined and characterized, despite phylogenetic and allometric effects. Application of this diet-biomechanics linkage model to an analysis of an extinct stem carnivoramorphan and an outgroup creodont species provides biomechanical evidence for the evolution of taxa into distinct hypercarnivorous and generalist feeding styles prior to the appearance of crown carnivoran clades with similar feeding preferences. PMID:25923776

  7. Are Cranial Biomechanical Simulation Data Linked to Known Diets in Extant Taxa? A Method for Applying Diet-Biomechanics Linkage Models to Infer Feeding Capability of Extinct Species

    PubMed Central

    Tseng, Zhijie Jack; Flynn, John J.

    2015-01-01

    Performance of the masticatory system directly influences feeding and survival, so adaptive hypotheses often are proposed to explain craniodental evolution via functional morphology changes. However, the prevalence of “many-to-one” association of cranial forms and functions in vertebrates suggests a complex interplay of ecological and evolutionary histories, resulting in redundant morphology-diet linkages. Here we examine the link between cranial biomechanical properties for taxa with different dietary preferences in crown clade Carnivora, the most diverse clade of carnivorous mammals. We test whether hypercarnivores and generalists can be distinguished based on cranial mechanical simulation models, and how such diet-biomechanics linkages relate to morphology. Comparative finite element and geometric morphometrics analyses document that predicted bite force is positively allometric relative to skull strain energy; this is achieved in part by increased stiffness in larger skull models and shape changes that resist deformation and displacement. Size-standardized strain energy levels do not reflect feeding preferences; instead, caniform models have higher strain energy than feliform models. This caniform-feliform split is reinforced by a sensitivity analysis using published models for six additional taxa. Nevertheless, combined bite force-strain energy curves distinguish hypercarnivorous versus generalist feeders. These findings indicate that the link between cranial biomechanical properties and carnivoran feeding preference can be clearly defined and characterized, despite phylogenetic and allometric effects. Application of this diet-biomechanics linkage model to an analysis of an extinct stem carnivoramorphan and an outgroup creodont species provides biomechanical evidence for the evolution of taxa into distinct hypercarnivorous and generalist feeding styles prior to the appearance of crown carnivoran clades with similar feeding preferences. PMID:25923776

  8. Physiological differentiation of viridans streptococci.

    PubMed Central

    Facklam, R R

    1977-01-01

    Twelve hundred and twenty-seven clinical isolates and eighty stock strains of viridans streptococci were tested for serological and physiological characteristics. Because the serological reactions of these strains varied, a differentiation scheme could not be based on these reactions. For the same reason, there could be no correlation of serological characteristics with physiological characteristics. Nearly 97% of the clinical isolates were speciated by differences in physiological characteristics. Ten different physiological species were recognized. The physiological speciation scheme was based on stable enzymatic reactions rather than on results of tolerance tests. The study included air-tolerant anaerobic streptococcal strains as well as viridans streptococcal strains not normally found in humans. The differentiation scheme and nomenclature of the author are related to those of other investigators. Differences in the distribution of species isolated from different clinical sources and human infections were also noted. A key for the differentiation of human isolates of viridans streptococci is proposed. PMID:845245

  9. The FORCLIM Eco-Physiological Growth Model for Planktic Foraminifera: a new Tool to Reconstruct Ecological Niches, Abundance and Potential Depth and Season of Growth for Fossil Foraminifera Species in Ocean Sediment Records

    NASA Astrophysics Data System (ADS)

    Lombard, F.; Labeyrie, L.; Michel, E.; Lea, D.; Spero, H. J.; Forclim, M. O.

    2007-12-01

    Paleocean hydrological reconstructions derived from planktic foraminifera isotopic ratios (δ18O and δ13C) or trace element ratio (Mg/Ca) are poorly constrained, for lack of precise knowledge on seasonality and water depth of test formation. This is particularly limiting for reconstruction of the thermocline characteristics. Various calibrations have been published, based on statistical correlation with core tops fossil fauna, sediment traps or plankton net collection. We present here what we think is the first eco-physiological model reproducing the growth of different foraminifera species in function of environmental parameter. By reproducing the main physiological rates of foraminifera (nutrition, respiration, symbiotic photosynthesis), this model estimates their growth in function of temperature, light availability and food concentration. The model is now calibrated for the species Neogloboquadrina pachyderma (dextral and sinistral forms), Neogloboquadrina dutertrei, Globigerina bulloides, Globigerinoides ruber, Globigerinoides sacculifer, Globigerinella siphonifera and Orbulina universa. Most of the model parameters are derived from newly performed experimental observations or from published data and only the influence of food concentration (in a Chl a basis) was calibrated with field observations. Using satellite data, the model predict the seasonal distribution of dominant foraminifer species over 576 field observations worldwide with efficiency higher than 60%. Moreover, the growth rate estimated for each foraminifera species can be used as an abundance indicator which allows prediction of the season and water depth at which most of the population has developed. This offers larges perspectives for both actual understanding of foraminifera role in the carbon/carbonate ocean cycle and for better quantification of paleoceanographic proxies. Forclim is a program supported by the Agence Nationale pour la Recherche and Institut National des Sciences de l

  10. Interaction of carbon dioxide and ozone on growth and physiology of C[sub 3] and C[sub 4] species

    SciTech Connect

    Volin, J.C.; Reich, P.B. Univ. of Minnesota, St. Paul )

    1993-06-01

    Six native tree and grass species from the forests and prairies of the Midwestern US, differing in stomatal conductance and photosynthetic pathway, were exposed to both ambient and elevated levels of carbon dioxide (CO[sub 2]) and ozone (O[sub 3]). Treatments consisted of all combinations of 350 [mu]L L[sup [minus]1] and 650 [mu]L L[sup [minus]1] CO[sub 2], and < 10 nL L[sup [minus]1] and 100 nL L[sup [minus]1] O[sub 3]. At ambient CO[sub 2], elevated O[sub 3] decreased whole-plant growth in three of the six species after 100 days of exposure. However, this decrease was only significant (P < 0.05) for the C[sub 3] grass species, Agropyron smithii and the tree species Populus tremuloides. Growth losses also occurred for the C[sub 3] grass, Koeleria cristata (P = 0.07) in elevated O[sub 3]. For these three species the deleterious effects of elevated O[sub 3] on whole-plant growth were ameliorated by elevated CO[sub 2]. There were no significant treatment effects on whole-plant growth for the two C[sub 4] grasses, Bouteloua curtipendula, and Schizachyrium scoparium and the tree species Quercus rubra. Photosynthesis measured in high-light for Agrpyron smithii, Koeleria cristata, Populus tremuloides and Schizachyrium scoparium, was reduced significantly (P < 0.05) by elevated O[sub 3] at ambient but not elevated levels of CO[sub 2].

  11. Molecular cloning, sequencing, and identification of a metalloprotease gene from Listeria monocytogenes that is species specific and physically linked to the listeriolysin gene.

    PubMed Central

    Domann, E; Leimeister-Wächter, M; Goebel, W; Chakraborty, T

    1991-01-01

    The entire nucleotide sequence of an open reading frame located immediately downstream of the listeriolysin gene from a virulent Listeria monocytogenes serotype 1/2a strain was determined. The product of the open reading frame was 510 amino acids with a predicted molecular weight of 57,400. The deduced amino acid sequence of this open reading frame is highly similar to that of a family of secreted metalloproteases produced by various members of the genus Bacillus, of which thermolysin is the prototype. Immunoblots performed with specific antisera raised against thermolysin from Bacillus stearothermophilus allowed the detection of a 60-kDa polypeptide, corresponding to the pro-form of the protease, in culture supernatants of L. monocytogenes strains. In maxicell experiments, Escherichia coli recombinants harboring this open reading frame also specifically directed production of a 60-kDa protein. Protease activity was low to undetectable in both Listeria strains and E. coli recombinants. This is due to lack of processing of the inactive pro-form of the protease to its mature active form in both species. We have designated this gene mpl for metalloprotease of L. monocytogenes. The gene was present only in pathogenic L. monocytogenes strains, in which it was physically linked to the listeriolysin gene. Images PMID:1898903

  12. Fruit Calcium: Transport and Physiology

    PubMed Central

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  13. Fruit Calcium: Transport and Physiology.

    PubMed

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  14. Are native naiads more tolerant to pollution than exotic freshwater bivalve species? An hypothesis tested using physiological responses of three species transplanted to mercury contaminated sites in the Ebro River (NE, Spain).

    PubMed

    Faria, Melissa; López, Miguel Angel; Díez, Sergi; Barata, Carlos

    2010-11-01

    In the lower Ebro River exist the paradoxical convergence of relatively well preserved river dynamics with the historical presence of a chloralkali plant with a long history of mercury discharges and the recent invasion of foreign bivalves species. Here we performed a comparative study on two alien bivalves, the Zebra mussel and the Asian clam (Dreissena polymorpha and Corbicula fluminea), and one protected species of naiads (Psilunio littoralis), which is the most common species of the freshwater mussel assemblages in this river. Individuals of the three species were transplanted to three sites that included a clean unpolluted upstream site, a contaminated location next to the mercury source and a downstream one. The study focused on digestive gland antioxidant and oxidative stress responses such as antioxidant enzymes, glutathione S transferase, glutathione levels, metallothionein proteins, DNA strand breaks and lipid peroxidation levels. Results evidenced interspecies differences on accumulation levels of mercury, antioxidant defensive systems and oxidative tissue damage. The naiad species, despite of accumulating more mercury showed the greatest antioxidant defensive potential, which was characterized by having high constitutive activities of glutathione S transferase and inducible activities and levels of key antioxidant enzymes and glutathione. Exposed individuals of C. fluminea had moderate levels of metal accumulation, the highest activities of antioxidant enzymes but also high levels of lipid peroxidation. D. polymorpha mussels showed the lowest levels of mercury but the lowest antioxidant responses and consequently the highest levels of oxidative injuries in the DNA and of mortality. Our results support the hypothesis that naiad species might be more tolerant to pollution than exotic species. PMID:20952043

  15. Cadmium-Induced Upregulation of Lipid Peroxidation and Reactive Oxygen Species Caused Physiological, Biochemical, and Ultrastructural Changes in Upland Cotton Seedlings

    PubMed Central

    Mei, Lei; Chen, Yue; Cheng, Xin; Zhu, S. J.

    2013-01-01

    Cadmium (Cd) toxicity was investigated in cotton cultivar (ZMS-49) using physiological, ultrastructural, and biochemical parameters. Biomass-based tolerance index decreased, and water contents increased at 500 μM Cd. Photosynthetic efficiency determined by chlorophyll fluorescence and photosynthetic pigments declined under Cd stress. Cd contents were more in roots than shoots. A significant decrease in nutrient levels was found in roots and stem. A significant decrease in nutrient levels was found in roots and stems. In response to Cd stress, more MDA and ROS contents were produced in leaves than in other parts of the seedlings. Total soluble proteins were reduced in all parts except in roots at 500 μM Cd. Oxidative metabolism was higher in leaves than aerial parts of the plant. There were insignificant alterations in roots and leaves ultrastructures such as a little increase in nucleoli, vacuoles, starch granules, and plastoglobuli in Cd-imposed stressful conditions. Scanning micrographs at 500 μM Cd showed a reduced number of stomata as well as near absence of closed stomata. Cd depositions were located in cell wall, vacuoles, and intracellular spaces using TEM-EDX technology. Upregulation of oxidative metabolism, less ultrastructural modification, and Cd deposition in dead parts of cells show that ZMS-49 has genetic potential to resist Cd stress, which need to be explored. PMID:24459668

  16. Seasonal and annual variations in physiological and biochemical responses from transplanted marine bioindicator species Mytilus spp. during a long term field exposure experiment.

    PubMed

    Helmholz, Heike; Ruhnau, Christiane; Pröfrock, Daniel; Erbslöh, Hans-Burkhard; Prange, Andreas

    2016-09-15

    In a pilot field study the long term response of transplanted bioindicator organisms Mytilus spp. was analyzed on the basis of physiological indices and biochemical measurements related to the energy budget. Three different time series with deployment times of eight to twelve months were compared according to seasonality and repeatability of the responses. Test organisms were incubated at a coastal station in the anthropogenically impacted estuary of the river Elbe and at a North Sea station located in vicinity to the Island of Helgoland in the German Bight. The stations differ in their hydrological as well as chemical characteristics. They can be discriminated by statistical factor analysis based on the measured biochemical parameter. Levels of all energy budget biomarker varied between seasons; however, the degree of variation of the specific response was differently expressed. The mussels deployed at Helgoland showed a reproducible high Condition Index in each sampling series and an oscillating Gonadosomatic Index representing the reproduction cycle. The lowest available energy was recorded in mussels at the estuarine sampling station compared to the off-shore station. This may be caused by the energetically costly maintenance of osmotic balance and consequently result in a lower amount of energy available for defense again chemical stress, growth and reproduction. PMID:27203523

  17. Eye spectral sensitivity in fresh- and brackish-water populations of three glacial-relict Mysis species (Crustacea): physiology and genetics of differential tuning.

    PubMed

    Donner, Kristian; Zak, Pavel; Viljanen, Martta; Lindström, Magnus; Feldman, Tatiana; Ostrovsky, Mikhail

    2016-04-01

    Absorbance spectra of single rhabdoms were studied by microspectrophotometry (MSP) and spectral sensitivities of whole eyes by electroretinography (ERG) in three glacial-relict species of opossum shrimps (Mysis). Among eight populations from Fennoscandian fresh-water lakes (L) and seven populations from the brackish-water Baltic Sea (S), L spectra were systematically red-shifted by 20-30 nm compared with S spectra, save for one L and one S population. The difference holds across species and bears no consistent adaptive relation to the current light environments. In the most extensively studied L-S pair, two populations of M. relicta (L(p) and S(p)) separated for less than 10,000 years, no differences translating into amino acid substitutions have been found in the opsin genes, and the chromophore of the visual pigments as analyzed by HPLC is pure A1. However, MSP experiments with spectrally selective bleaching show the presence of two rhodopsins (λ(max) ≈ 525-530 nm, MWS, and 565-570 nm, LWS) expressed in different proportions. ERG recordings of responses to "red" and "blue" light linearly polarized at orthogonal angles indicate segregation of the pigments into different cells differing in polarization sensitivity. We propose that the pattern of development of LWS and MWS photoreceptors is governed by an ontogenetic switch responsive to some environmental signal(s) other than light that generally differ(s) between lakes and sea, and that this reaction norm is conserved from a common ancestor of all three species. PMID:26984686

  18. Pervasive Sex-Linked Effects on Transcription Regulation As Revealed by Expression Quantitative Trait Loci Mapping in Lake Whitefish Species Pairs (Coregonus sp., Salmonidae)

    PubMed Central

    Derome, N.; Bougas, B.; Rogers, S. M.; Whiteley, A. R.; Labbe, A.; Laroche, J.; Bernatchez, L.

    2008-01-01

    Mapping of expression quantitative trait loci (eQTL) is a powerful means for elucidating the genetic architecture of gene regulation. Yet, eQTL mapping has not been applied toward investigating the regulation architecture of genes involved in the process of population divergence, ultimately leading to speciation events. Here, we conducted an eQTL mapping experiment to compare the genetic architecture of transcript regulation in adaptive traits, differentiating the recently evolved limnetic (dwarf) and benthic (normal) species pairs of lake whitefish. The eQTL were mapped in three data sets derived from an F1 hybrid-dwarf backcrossed family: the entire set of 66 genotyped individuals and the two sexes treated separately. We identified strikingly more eQTL in the female data set (174), compared to both male (54) and combined (33) data sets. The majority of these genes were not differentially expressed between male and female progeny of the backcross family, thus providing evidence for a strong pleiotropic sex-linked effect in transcriptomic regulation. The subtelomeric region of a linkage group segregating in females encompassed >50% of all eQTL, which exhibited the most pronounced additive effects. We also conducted a direct comparison of transcriptomic profiles between pure dwarf and normal progeny reared in controlled conditions. We detected 34 differentially expressed transcripts associated with eQTL segregating only in sex-specific data sets and mostly belonging to functional groups that differentiate dwarf and normal whitefish in natural populations. Therefore, these eQTL are not related to interindividual variation, but instead to the adaptive and historical genetic divergence between dwarf and normal whitefish. This study exemplifies how the integration of genetic and transcriptomic data offers a strong means for dissecting the functional genomic response to selection by separating mapping family-specific effects from genetic factors under selection

  19. Living in biological soil crust communities of African deserts-Physiological traits of green algal Klebsormidium species (Streptophyta) to cope with desiccation, light and temperature gradients.

    PubMed

    Karsten, Ulf; Herburger, Klaus; Holzinger, Andreas

    2016-05-01

    Green algae of the genus Klebsormidium (Klebsormidiales, Streptophyta) are typical members of biological soil crusts (BSCs) worldwide. The phylogeny and ecophysiology of Klebsormidium has been intensively studied in recent years, and a new lineage called superclade G, which was isolated from BSCs in arid southern Africa and comprising undescribed species, was reported. Three different African strains, that have previously been isolated from hot-desert BSCs and molecular-taxonomically characterized, were comparatively investigated. In addition, Klebsormidium subtilissimum from a cold-desert habitat (Alaska, USA, superclade E) was included in the study as well. Photosynthetic performance was measured under different controlled abiotic conditions, including dehydration and rehydration, as well as under a light and temperature gradient. All Klebsormidium strains exhibited optimum photosynthetic oxygen production at low photon fluence rates, but with no indication of photoinhibition under high light conditions pointing to flexible acclimation mechanisms of the photosynthetic apparatus. Respiration under lower temperatures was generally much less effective than photosynthesis, while the opposite was true for higher temperatures. The Klebsormidium strains tested showed a decrease and inhibition of the effective quantum yield during desiccation, however with different kinetics. While the single celled and small filamentous strains exhibited relatively fast inhibition, the uniserate filament forming isolates desiccated slower. Except one, all other strains fully recovered effective quantum yield after rehydration. The presented data provide an explanation for the regular occurrence of Klebsormidium strains or species in hot and cold deserts, which are characterized by low water availability and other stressful conditions. PMID:26422081

  20. Functional evidence for physiological mechanisms to circumvent neurotoxicity of cardenolides in an adapted and a non-adapted hawk-moth species.

    PubMed

    Petschenka, Georg; Pick, Christian; Wagschal, Vera; Dobler, Susanne

    2013-05-22

    Because cardenolides specifically inhibit the Na(+)K(+)-ATPase, insects feeding on cardenolide-containing plants need to circumvent this toxic effect. Some insects such as the monarch butterfly rely on target site insensitivity, yet other cardenolide-adapted lepidopterans such as the oleander hawk-moth, Daphnis nerii, possess highly sensitive Na(+)K(+)-ATPases. Nevertheless, larvae of this species and the related Manduca sexta are insensitive to injected cardenolides. By radioactive-binding assays with nerve cords of both species, we demonstrate that the perineurium surrounding the nervous tissue functions as a diffusion barrier for a polar cardenolide (ouabain). By contrast, for non-polar cardenolides such as digoxin an active efflux carrier limits the access to the nerve cord. This barrier can be abolished by metabolic inhibitors and by verapamil, a specific inhibitor of P-glycoproteins (PGPs). This supports that a PGP-like transporter is involved in the active cardenolide-barrier of the perineurium. Tissue specific RT-PCR demonstrated expression of three PGP-like genes in hornworm nerve cords, and immunohistochemistry further corroborated PGP expression in the perineurium. Our results thus suggest that the lepidopteran perineurium serves as a diffusion barrier for polar cardenolides and provides an active barrier for non-polar cardenolides. This may explain the high in vivo resistance to cardenolides observed in some lepidopteran larvae, despite their highly sensitive Na(+)K(+)-ATPases. PMID:23516239

  1. Functional evidence for physiological mechanisms to circumvent neurotoxicity of cardenolides in an adapted and a non-adapted hawk-moth species

    PubMed Central

    Petschenka, Georg; Pick, Christian; Wagschal, Vera; Dobler, Susanne

    2013-01-01

    Because cardenolides specifically inhibit the Na+K+-ATPase, insects feeding on cardenolide-containing plants need to circumvent this toxic effect. Some insects such as the monarch butterfly rely on target site insensitivity, yet other cardenolide-adapted lepidopterans such as the oleander hawk-moth, Daphnis nerii, possess highly sensitive Na+K+-ATPases. Nevertheless, larvae of this species and the related Manduca sexta are insensitive to injected cardenolides. By radioactive-binding assays with nerve cords of both species, we demonstrate that the perineurium surrounding the nervous tissue functions as a diffusion barrier for a polar cardenolide (ouabain). By contrast, for non-polar cardenolides such as digoxin an active efflux carrier limits the access to the nerve cord. This barrier can be abolished by metabolic inhibitors and by verapamil, a specific inhibitor of P-glycoproteins (PGPs). This supports that a PGP-like transporter is involved in the active cardenolide-barrier of the perineurium. Tissue specific RT-PCR demonstrated expression of three PGP-like genes in hornworm nerve cords, and immunohistochemistry further corroborated PGP expression in the perineurium. Our results thus suggest that the lepidopteran perineurium serves as a diffusion barrier for polar cardenolides and provides an active barrier for non-polar cardenolides. This may explain the high in vivo resistance to cardenolides observed in some lepidopteran larvae, despite their highly sensitive Na+K+-ATPases. PMID:23516239

  2. Living in biological soil crust communities of African deserts—Physiological traits of green algal Klebsormidium species (Streptophyta) to cope with desiccation, light and temperature gradients

    PubMed Central

    Karsten, Ulf; Herburger, Klaus; Holzinger, Andreas

    2015-01-01

    Green algae of the genus Klebsormidium (Klebsormidiales, Streptophyta) are typical members of biological soil crusts (BSCs) worldwide. The phylogeny and ecophysiology of Klebsormidium has been intensively studied in recent years, and a new lineage called superclade G, which was isolated from BSCs in arid southern Africa and comprising undescribed species, was reported. Three different African strains, that have previously been isolated from hot-desert BSCs and molecular-taxonomically characterized, were comparatively investigated. In addition, Klebsormidium subtilissimum from a cold-desert habitat (Alaska, USA, superclade E) was included in the study as well. Photosynthetic performance was measured under different controlled abiotic conditions, including dehydration and rehydration, as well as under a light and temperature gradient. All Klebsormidium strains exhibited optimum photosynthetic oxygen production at low photon fluence rates, but with no indication of photoinhibition under high light conditions pointing to flexible acclimation mechanisms of the photosynthetic apparatus. Respiration under lower temperatures was generally much less effective than photosynthesis, while the opposite was true for higher temperatures. The Klebsormidium strains tested showed a decrease and inhibition of the effective quantum yield during desiccation, however with different kinetics. While the single celled and small filamentous strains exhibited relatively fast inhibition, the uniserate filament forming isolates desiccated slower. Except one, all other strains fully recovered effective quantum yield after rehydration. The presented data provide an explanation for the regular occurrence of Klebsormidium strains or species in hot and cold deserts, which are characterized by low water availability and other stressful conditions. PMID:26422081

  3. Comparative Physiological Evidence that β-Alanine Betaine and Choline-O-Sulfate Act as Compatible Osmolytes in Halophytic Limonium Species 1

    PubMed Central

    Hanson, Andrew D.; Rathinasabapathi, Bala; Chamberlin, Beverly; Gage, Douglas A.

    1991-01-01

    The quaternary ammonium compounds accumulated in saline conditions by five salt-tolerant species of Limonium (Plumbaginaceae) were analyzed by fast atom bombardment mass spectrometry. Three species accumulated β-alanine betaine and choline-O-sulfate; the others accumulated glycine betaine and choline-O-sulfate. Three lines of evidence indicated that β-alanine betaine and choline-O-sulfate replace glycine betaine as osmo-regulatory solutes. First, tests with bacteria showed that β-alanine betaine and choline-O-sulfate have osmoprotective properties comparable to glycine betaine. Second, when β-alanine betaine and glycine betaine accumulators were salinized, the levels of their respective betaines, plus that of choline-O-sulfate, were closely correlated with leaf solute potential. Third, substitution of sulfate for chloride salinity caused an increase in the level of choline-O-sulfate and a matching decrease in glycine betaine level. Experiments with 14C-labeled precursors established that β-alanine betaine accumulators did not synthesize glycine betaine and vice versa. These experiments also showed that β-alanine betaine synthesis occurs in roots as well as leaves of β-alanine betaine accumulators and that choline-O-sulfate and glycine betaine share choline as a precursor. Unlike glycine betaine, β-alanine betaine synthesis cannot interfere with conjugation of sulfate to choline by competing for choline and does not require oxygen. These features of β-alanine betaine may be advantageous in sulfate-rich salt marsh environments. PMID:16668509

  4. Physiological Acoustics

    NASA Astrophysics Data System (ADS)

    Young, Eric D.

    The analysis of physiological sound in the peripheral auditory system solves three important problems. First, sound energy impinging on the head must be captured and presented to the transduction apparatus in the ear as a suitable mechanical signal; second, this mechanical signal needs to be transduced into a neural representation that can be used by the brain; third, the resulting neural representation needs to be analyzed by central neurons to extract information useful to the animal. This chapter provides an overview of some aspects of the first two of these processes. The description is entirely focused on the mammalian auditory system, primarily on human hearing and on the hearing of a few commonly used laboratory animals (mainly rodents and carnivores). Useful summaries of non-mammalian hearing are available [1]. Because of the large size of the literature, review papers are referenced wherever possible.

  5. The role of thermal physiology in recent declines of birds in a biodiversity hotspot

    PubMed Central

    Milne, Robyn; Cunningham, Susan J.; Lee, Alan T. K.; Smit, Ben

    2015-01-01

    We investigated whether observed avian range contractions and population declines in the Fynbos biome of South Africa were mechanistically linked to recent climate warming. We aimed to determine whether there were correlations between preferred temperature envelope, or changes in temperature within species' ranges, and recent changes in range and population size, for 12 Fynbos-resident bird species, including six that are endemic to the biome. We then measured the physiological responses of each species at air temperatures ranging from 24 to 42°C to determine whether physiological thermal thresholds could provide a mechanistic explanation for observed population trends. Our data show that Fynbos-endemic species occupying the coolest regions experienced the greatest recent reductions in range and population size (>30% range reduction between 1991 and the present). In addition, species experiencing the largest increases in air temperature within their ranges showed the greatest declines. However, evidence for a physiological mechanistic link between warming and population declines was equivocal, with only the larger species showing low thermal thresholds for their body mass, compared with other birds globally. In addition, some species appear more vulnerable than others to air temperatures in their ranges above physiological thermal thresholds. Of these, the high-altitude specialist Cape rockjumper (Chaetops frenatus) seems most at risk from climate warming. This species showed: (i) the lowest threshold for increasing evaporative water loss at high temperatures; and (ii) population declines specifically in those regions of its range recording significant warming trends. Our findings suggest that caution must be taken when attributing causality explicitly to thermal stress, even when population trends are clearly correlated with rates of warming. Studies explicitly investigating the mechanisms underlying such correlations will be key to appropriate conservation

  6. Space Physiology within an Exercise Physiology Curriculum

    ERIC Educational Resources Information Center

    Carter, Jason R.; West, John B.

    2013-01-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of…

  7. Epidemiology and Pulmonary Physiology of Severe Asthma.

    PubMed

    O'Toole, Jacqueline; Mikulic, Lucas; Kaminsky, David A

    2016-08-01

    The epidemiology and physiology of severe asthma are inherently linked because of varying phenotypes and expressions of asthma throughout the population. To understand how to better treat severe asthma, we must use both population data and physiologic principles to individualize therapies among groups with similar expressions of this disease. PMID:27401616

  8. A missing geographic link in the distribution of the genus Echinotriton (Caudata: Salamandridae) with description of a new species from southern China.

    PubMed

    Hou, Mian; Wu, Yunke; Yang, Kelin; Zheng, Sheng; Yuan, Zhiyong; Li, Pipeng

    2014-01-01

    Disjunct geographic distribution of a species or a group of species is the product of long-term interaction between organisms and the environment. Filling the distributional gap by discovery of a new population or a species has significant biogeographic implications, because it suggests a much wider past distribution and provides evidence for the route of range expansion/contraction. The salamandrid genus Echinotriton (commonly known as spiny salamanders, spiny newts, or crocodile newts) has two species that are restricted to two widely separated areas, one in eastern Zhejiang province, China and the other in the Ryukyu Archipelago of Japan. It has been hypothesized that Echinotriton was once continuously distributed between the two areas through a historical land bridge that connected mainland China, Taiwan, and the archipelago. Finding fossils or relic populations along the postulated distribution are strong evidence for the hypothesis. Hundred-twenty-two years after the description of E. andersoni and eight-one years after that of E. chinhaiensis, we discover a third species of Echinotriton in southern China, which fills the distributional gap of the former two species. Species status of the new species is confirmed through molecular phylogenetic analysis and morphological comparison. Mitochondrial DNA indicates that the new species is sister to E. chinhaiensis, while nuclear DNA does not support this relationship. The new species has a very large quadrate projection, a single line of lateral warts pierced by distal rib extremities, normally developed 5th toes, and conical skin tubercles. Our discovery supports the hypothesis that there was a continuous distribution of Echinotriton from eastern coastal China to the Ryukyu Archipelago. We suggest that other species of this genus may also be found in Taiwan. Due to the rarity of this new species, we urge all hobbyists to refrain themselves from collecting this salamander or leaking locality information if

  9. Fitness and physiology in a variable environment.

    PubMed

    Kimball, Sarah; Gremer, Jennifer R; Angert, Amy L; Huxman, Travis E; Venable, D Lawrence

    2012-06-01

    The relationship between physiological traits and fitness often depends on environmental conditions. In variable environments, different species may be favored through time, which can influence both the nature of trait evolution and the ecological dynamics underlying community composition. To determine how fluctuating environmental conditions favor species with different physiological traits over time, we combined long-term data on survival and fecundity of species in a desert annual plant community with data on weather and physiological traits. For each year, we regressed the standardized annual fitness of each species on its position along a tradeoff between relative growth rate and water-use efficiency. Next, we determined how variations in the slopes and intercepts of these fitness-physiology functions related to year-to-year variations in temperature and precipitation. Years with a relatively high percentage of small rain events and a greater number of days between precipitation pulse events tended to be worse, on average, for all desert annual species. Species with high relative growth rates and low water-use efficiency had greater standardized annual fitness than other species in years with greater numbers of large rain events. Conversely, species with high water-use efficiency had greater standardized annual fitness in years with small rain events and warm temperatures late in the growing season. These results reveal how weather variables interact with physiological traits of co-occurring species to determine interannual variations in survival and fecundity, which has important implications for understanding population and community dynamics. PMID:22116505

  10. Network Physiology: How Organ Systems Dynamically Interact

    PubMed Central

    Bartsch, Ronny P.; Liu, Kang K. L.; Bashan, Amir; Ivanov, Plamen Ch.

    2015-01-01

    We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

  11. Network Physiology: How Organ Systems Dynamically Interact.

    PubMed

    Bartsch, Ronny P; Liu, Kang K L; Bashan, Amir; Ivanov, Plamen Ch

    2015-01-01

    We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

  12. Corneal cross-linking.

    PubMed

    Randleman, J Bradley; Khandelwal, Sumitra S; Hafezi, Farhad

    2015-01-01

    Since its inception in the late 1990s, corneal cross-linking has grown from an interesting concept to a primary treatment for corneal ectatic disease worldwide. Using a combination of ultraviolet-A light and a chromophore (vitamin B2, riboflavin), the cornea can be stiffened, usually with a single application, and progressive thinning diseases such as keratoconus arrested. Despite being in clinical use for many years, some of the underlying processes, such as the role of oxygen and the optimal treatment times, are still being worked out. More than a treatment technique, corneal cross-links represent a physiological principle of connective tissue, which may explain the enormous versatility of the method. We highlight the history of corneal cross-linking, the scientific underpinnings of current techniques, evolving clinical treatment parameters, and the use of cross-linking in combination with refractive surgery and for the treatment of infectious keratitis. PMID:25980780

  13. Species of Apatemon Szidat, 1928 and Australapatemon Sudarikov, 1959 (Trematoda: Strigeidae) from New Zealand: linking and characterising life cycle stages with morphology and molecules.

    PubMed

    Blasco-Costa, Isabel; Poulin, Robert; Presswell, Bronwen

    2016-01-01

    Species of Apatemon Szidat, 1928 and Australapatemon Sudarikov, 1959 are reported from New Zealand for the first time, and their life cycles are resolved using molecular sequence data (28S and ITS rDNA regions and mitochondrial COI). The metacercaria of Apatemon sp. 'jamiesoni' ex Gobiomorphus cotidianus and its cercaria ex Potamopyrgus antipodarum are described in detail. Its adult, found in Anas platyrhynchos and Phalacrocorax punctatus, is identified by molecular sequence data. Apatemon sp. 'jamiesoni' uses a different species of snail host, exhibits consistent differences in the genetic markers examined and its single described adult differs from known species so as to be considered distinct, but its formal description awaits additional adult specimens. Australapatemon niewiadomski n. sp. is described from Anas platyrhynchos. It is distinguished morphologically by the absence of a ringnapf and its overall smaller size compared to most other Australapatemon spp. except Au. magnacetabulum and Au. minor, which are smaller in nearly all features than the new species. Au. niewiadomski n. sp. metacercaria and its intermediate host (Barbronia weberi) are identified via matching of molecular sequence data. The status of Apatemon and Australapatemon as distinct genera is confirmed based on their respective monophyly, and genetic divergence between them is comparable to other well-established genera in the Strigeidae. The diagnosis of Australapatemon is emended. Life history data, accurate patterns of host specialisation and distribution, alongside concurrent molecular and morphological evidence would be useful for an integrative taxonomical approach towards the elucidation of species diversity in this group. PMID:26385467

  14. Linking biogeographic and life history information for nonindigenous marine and estuarine species in the North Pacific: An introduction to the Pacific Coast Ecological Information System (PCEIS)

    EPA Science Inventory

    Nonindigenous species (NIS) are a pervasive problem throughout the world. To help address this threat the EPA and USGS have developed a hierarchical database (PCEIS) that synthesizes existing biogeographic, life history, and invasion history information for near-coastal and estu...

  15. Linking biogeographic and life history information for nonindigenous marine and estuarine species in the North Pacific: An introduction to the Pacific Coast Ecological Information System (PCEIS) November 2011

    EPA Science Inventory

    Nonindigenous species (NIS) are a pervasive problem throughout the world. To help address this threat the EPA and USGS have developed a hierarchical database (PCEIS) that synthesizes existing biogeographic, life history, and invasion history information for near-coastal and estu...

  16. Effects of resource availability on plant reflectance and physiology

    NASA Astrophysics Data System (ADS)

    Stylinski, Cathlyn Davis

    Remote sensing is an important means of examining net CO2 exchange between terrestrial ecosystems and the atmosphere and the effects of elevated [CO2] on plant productivity at multiple spatial and temporal scales. In particular, indices derived from narrow-waveband reflectance that are sensitive to dynamic physiological attributes may reveal periods of photosynthetic downregulation and may improve plant productivity models. Here we examined the relationship between photosynthesis, photoprotective xanthophyll cycle pigments, and the Photochemical Reflectance Index (PRI) for mature woody Mediterranean plants under two conditions: natural drought and exposure to atmospheric CO2 enrichment. We also examined plants under severe water stress to test and compare the effects of physiology and structure on PRI, the Normalized Difference Vegetation Index (NDVI), and the Water Band Index (WBI). PRI varied primarily with leaf physiology, and NDVI primarily with stand structure. WBI was affected by both attributes and, unlike PRI, did not scale well from leaves to whole stands. PRI was well linked to photoprotective xanthophyll cycle pigments and electron transport. Both PRI and these pigments varied with seasonal changes in midday photosynthesis, demonstrating that the xanthophyll cycle is an important form of photoprotection for evergreen Mediterranean species undergoing photosynthetic downregulation. By contrast, NDVI was not sensitive to physiological changes but was well correlated with green canopy cover. These results suggest that the "big-leaf hypothesis" (which states that canopies can be characterized by a single reference leaf) cannot be applied to all physiological indices. Furthermore, in agreement with the "functional convergence hypothesis" (which states that plant physiology and structure change to match CO2 fixation capacity), our results indicate a coordinated regulation of photosystem two activity and carbon uptake. However, they also demonstrate that this

  17. Variation in rDNA locus number and position among legume species and detection of 2 linked rDNA loci in the model Medicago truncatula by FISH.

    PubMed

    Abirached-Darmency, Mona; Prado-Vivant, Emilce; Chelysheva, Liudmila; Pouthier, Thomas

    2005-06-01

    Within Fabaceae, legume species have a variable genome size, chromosome number, and ploidy level. The genome distribution of ribosomal genes, easily detectable by fluorescent in situ hybridization (FISH), is a good tool for anchoring physical and genetic comparative maps. The organisation of 45S rDNA and 5S loci was analysed by FISH in the 4 closely related species: Pisum sativum, Medicago truncatula, Medicago sativa (2 diploid taxa), and Lathyrus sativus. The 2 types of rDNA arrays displayed interspecific variation in locus number and location, but little intraspecific variation was detected. In the model legume, M. truncatula, the presence of 2 adjacent 45S rDNA loci was demonstrated, and the location of the rDNA loci was independent of the general evolution of the genome DNA. The different parameters relative to clustering of the rDNA loci in specific chromosome regions and the possible basis of rDNA instability are discussed. PMID:16121252

  18. Is there a missing link? Effects of root herbivory on plant-pollinator interactions and reproductive output in a monocarpic species.

    PubMed

    Ghyselen, C; Bonte, D; Brys, R

    2016-01-01

    Herbivores can have a major influence on plant fitness. The direct impact of herbivory on plant reproductive output has long been studied, and recently also indirect effects of herbivory on plant traits and pollinator attraction have received increasing attention. However, the link between these direct and indirect effects has seldom been studied. In this study, we investigated effects of root herbivory on plant and floral traits, pollination success and reproductive outcome in the monocarpic perennial Cynoglossum officinale. We exposed 119 C. officinale plants to a range of root herbivore damage by its specialist herbivore Mogulones cruciger. We assessed the effect of herbivory on several plant traits, pollinator foraging behaviour and reproductive output, and to elucidate the link between these last two we also quantified pollen deposition and pollen tube growth and applied a pollination experiment to test whether seed set was pollen-limited. Larval root herbivory induced significant changes in plant traits and had a negative impact on pollinator visitation. Infested plants were reduced in size, had fewer flowers and received fewer pollinator visits at plant and flower level than non-infested plants. Also, seed set was negatively affected by root herbivory, but this could not be attributed to pollen limitation since neither stigmatic pollen loads and pollen tube growth nor the results of the hand-pollination experiment differed between infested and non-infested plants. Our observations demonstrate that although herbivory may induce significant changes in flowering behaviour and resulting plant-pollinator interactions, it does not necessarily translate into higher rates of pollen limitation. The observed reductions in reproductive output following infection can mainly be attributed to higher resource limitation compared to non-infested plants. PMID:25731922

  19. Are accessory hearing structures linked to inner ear morphology? Insights from 3D orientation patterns of ciliary bundles in three cichlid species

    PubMed Central

    2014-01-01

    D context in studies of inner ear morphology and physiology. PMID:24645675

  20. Space physiology within an exercise physiology curriculum.

    PubMed

    Carter, Jason R; West, John B

    2013-09-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of chronic terrestrial exercise (TEx) and microgravity (μG). We used a series of peer-reviewed publications to demonstrate that many of the physiological adaptations to TEx and μG are opposite. For example, TEx typically improves cardiovascular function and orthostatic tolerance, whereas μG can lead to declines in both. TEx leads to muscle hypertrophy, and μG elicits muscle atrophy. TEx increases bone mineral density and red blood cell mass, whereas μG decreases bone mineral density and red blood cell mass. Importantly, exercise during spaceflight remains a crucial countermeasure to limit some of these adverse physiological adaptations to μG. This curriculum develops critical thinking skills by dissecting peer-reviewed articles and discussing the strengths and weaknesses associated with simulated and actual μG studies. Moreover, the curriculum includes studies on both animals and humans, providing a strong translational component to the curriculum. In summary, we have developed a novel space physiology curriculum delivered during the final weeks of an exercise physiology course in which students gain critical new knowledge that reinforces key concepts presented throughout the semester. PMID:24022767

  1. A Syntenic Cross Species Aneuploidy Genetic Screen Links RCAN1 Expression to β-Cell Mitochondrial Dysfunction in Type 2 Diabetes

    PubMed Central

    Peiris, Heshan; Duffield, Michael D.; Fadista, Joao; Kashmir, Vinder; Genders, Amanda J.; McGee, Sean L.; Martin, Alyce M.; Saiedi, Madiha; Morton, Nicholas; Carter, Roderick; Cousin, Michael A.; Oskolkov, Nikolay; Volkov, Petr; Hough, Tertius A.; Fisher, Elizabeth M. C.; Tybulewicz, Victor L. J.; Busciglio, Jorge; Coskun, Pinar E.; Becker, Ann; Belichenko, Pavel V.; Mobley, William C.; Ryan, Michael T.; Chan, Jeng Yie; Laybutt, D. Ross; Coates, P. Toby; Yang, Sijun; Ling, Charlotte; Groop, Leif; Pritchard, Melanie A.; Keating, Damien J.

    2016-01-01

    Type 2 diabetes (T2D) is a complex metabolic disease associated with obesity, insulin resistance and hypoinsulinemia due to pancreatic β-cell dysfunction. Reduced mitochondrial function is thought to be central to β-cell dysfunction. Mitochondrial dysfunction and reduced insulin secretion are also observed in β-cells of humans with the most common human genetic disorder, Down syndrome (DS, Trisomy 21). To identify regions of chromosome 21 that may be associated with perturbed glucose homeostasis we profiled the glycaemic status of different DS mouse models. The Ts65Dn and Dp16 DS mouse lines were hyperglycemic, while Tc1 and Ts1Rhr mice were not, providing us with a region of chromosome 21 containing genes that cause hyperglycemia. We then examined whether any of these genes were upregulated in a set of ~5,000 gene expression changes we had identified in a large gene expression analysis of human T2D β-cells. This approach produced a single gene, RCAN1, as a candidate gene linking hyperglycemia and functional changes in T2D β-cells. Further investigations demonstrated that RCAN1 methylation is reduced in human T2D islets at multiple sites, correlating with increased expression. RCAN1 protein expression was also increased in db/db mouse islets and in human and mouse islets exposed to high glucose. Mice overexpressing RCAN1 had reduced in vivo glucose-stimulated insulin secretion and their β-cells displayed mitochondrial dysfunction including hyperpolarised membrane potential, reduced oxidative phosphorylation and low ATP production. This lack of β-cell ATP had functional consequences by negatively affecting both glucose-stimulated membrane depolarisation and ATP-dependent insulin granule exocytosis. Thus, from amongst the myriad of gene expression changes occurring in T2D β-cells where we had little knowledge of which changes cause β-cell dysfunction, we applied a trisomy 21 screening approach which linked RCAN1 to β-cell mitochondrial dysfunction in T2D

  2. A Syntenic Cross Species Aneuploidy Genetic Screen Links RCAN1 Expression to β-Cell Mitochondrial Dysfunction in Type 2 Diabetes.

    PubMed

    Peiris, Heshan; Duffield, Michael D; Fadista, Joao; Jessup, Claire F; Kashmir, Vinder; Genders, Amanda J; McGee, Sean L; Martin, Alyce M; Saiedi, Madiha; Morton, Nicholas; Carter, Roderick; Cousin, Michael A; Kokotos, Alexandros C; Oskolkov, Nikolay; Volkov, Petr; Hough, Tertius A; Fisher, Elizabeth M C; Tybulewicz, Victor L J; Busciglio, Jorge; Coskun, Pinar E; Becker, Ann; Belichenko, Pavel V; Mobley, William C; Ryan, Michael T; Chan, Jeng Yie; Laybutt, D Ross; Coates, P Toby; Yang, Sijun; Ling, Charlotte; Groop, Leif; Pritchard, Melanie A; Keating, Damien J

    2016-05-01

    Type 2 diabetes (T2D) is a complex metabolic disease associated with obesity, insulin resistance and hypoinsulinemia due to pancreatic β-cell dysfunction. Reduced mitochondrial function is thought to be central to β-cell dysfunction. Mitochondrial dysfunction and reduced insulin secretion are also observed in β-cells of humans with the most common human genetic disorder, Down syndrome (DS, Trisomy 21). To identify regions of chromosome 21 that may be associated with perturbed glucose homeostasis we profiled the glycaemic status of different DS mouse models. The Ts65Dn and Dp16 DS mouse lines were hyperglycemic, while Tc1 and Ts1Rhr mice were not, providing us with a region of chromosome 21 containing genes that cause hyperglycemia. We then examined whether any of these genes were upregulated in a set of ~5,000 gene expression changes we had identified in a large gene expression analysis of human T2D β-cells. This approach produced a single gene, RCAN1, as a candidate gene linking hyperglycemia and functional changes in T2D β-cells. Further investigations demonstrated that RCAN1 methylation is reduced in human T2D islets at multiple sites, correlating with increased expression. RCAN1 protein expression was also increased in db/db mouse islets and in human and mouse islets exposed to high glucose. Mice overexpressing RCAN1 had reduced in vivo glucose-stimulated insulin secretion and their β-cells displayed mitochondrial dysfunction including hyperpolarised membrane potential, reduced oxidative phosphorylation and low ATP production. This lack of β-cell ATP had functional consequences by negatively affecting both glucose-stimulated membrane depolarisation and ATP-dependent insulin granule exocytosis. Thus, from amongst the myriad of gene expression changes occurring in T2D β-cells where we had little knowledge of which changes cause β-cell dysfunction, we applied a trisomy 21 screening approach which linked RCAN1 to β-cell mitochondrial dysfunction in T2D

  3. Physiology of Mycobacteria

    PubMed Central

    Cook, Gregory M.; Berney, Michael; Gebhard, Susanne; Heinemann, Matthias; Cox, Robert A.; Danilchanka, Olga; Niederweis, Michael

    2013-01-01

    Mycobacterium tuberculosis is a prototrophic, metabolically flexible bacterium that has achieved a spread in the human population that is unmatched by any other bacterial pathogen. The success of M. tuberculosis as a pathogen can be attributed to its extraordinary stealth and capacity to adapt to environmental changes throughout the course of infection. These changes include: nutrient deprivation, hypoxia, various exogenous stress conditions and, in the case of the pathogenic species, the intraphagosomal environment. Knowledge of the physiology of M. tuberculosis during this process has been limited by the slow growth of the bacterium in the laboratory and other technical problems such as cell aggregation. Advances in genomics and molecular methods to analyse the M. tuberculosis genome have revealed that adaptive changes are mediated by complex regulatory networks and signals, resulting in temporal gene expression coupled to metabolic and energetic changes. An important goal for bacterial physiologists will be to elucidate the physiology of M. tuberculosis during the transition between the diverse conditions encountered by M. tuberculosis. This review covers the growth of the mycobacterial cell and how environmental stimuli are sensed by this bacterium. Adaptation to different environments is described from the viewpoint of nutrient acquisition, energy generation and regulation. To gain quantitative understanding of mycobacterial physiology will require a systems biology approach and recent efforts in this area are discussed. “It is now 100 years since the first mycobacterium was isolated by Hansen (1874). Somewhat ironically, this was the leprosy bacillus, Mycobacterium leprae, which even today is still resisting all attempts to cultivate it in the laboratory. The tubercle bacillus, M. tuberculosis was not discovered until eight years later (Koch, 1882) and this has remained an object of intensive investigation ever since. The widespread interest in the

  4. Physiological Information Database (PID)

    EPA Science Inventory

    EPA has developed a physiological information database (created using Microsoft ACCESS) intended to be used in PBPK modeling. The database contains physiological parameter values for humans from early childhood through senescence as well as similar data for laboratory animal spec...

  5. Linking regional variation of epibiotic bacterial diversity and trophic ecology in a new species of Kiwaidae (Decapoda, Anomura) from East Scotia Ridge (Antarctica) hydrothermal vents.

    PubMed

    Zwirglmaier, Katrin; Reid, William D K; Heywood, Jane; Sweeting, Christopher J; Wigham, Benjamin D; Polunin, Nicholas V C; Hawkes, Jeff A; Connelly, Douglas P; Pearce, David; Linse, Katrin

    2015-02-01

    We analyzed the diversity of bacterial epibionts and trophic ecology of a new species of Kiwa yeti crab discovered at two hydrothermal vent fields (E2 and E9) on the East Scotia Ridge (ESR) in the Southern Ocean using a combination of 454 pyrosequencing, Sanger sequencing, and stable isotope analysis. The Kiwa epibiont communities were dominated by Epsilon- and Gammaproteobacteria. About 454 sequencing of the epibionts on 15 individual Kiwa specimen revealed large regional differences between the two hydrothermal vent fields: at E2, the bacterial community on the Kiwa ventral setae was dominated (up to 75%) by Gammaproteobacteria, whereas at E9 Epsilonproteobacteria dominated (up to 98%). Carbon stable isotope analysis of both Kiwa and the bacterial epibionts also showed distinct differences between E2 and E9 in mean and variability. Both stable isotope and sequence data suggest a dominance of different carbon fixation pathways of the epibiont communities at the two vent fields. At E2, epibionts were putatively fixing carbon via the Calvin-Benson-Bassham and reverse tricarboxylic acid cycle, while at E9 the reverse tricarboxylic acid cycle dominated. Co-varying epibiont diversity and isotope values at E2 and E9 also present further support for the hypothesis that epibionts serve as a food source for Kiwa. PMID:25515351

  6. Linking regional variation of epibiotic bacterial diversity and trophic ecology in a new species of Kiwaidae (Decapoda, Anomura) from East Scotia Ridge (Antarctica) hydrothermal vents

    PubMed Central

    Zwirglmaier, Katrin; Reid, William D K; Heywood, Jane; Sweeting, Christopher J; Wigham, Benjamin D; Polunin, Nicholas V C; Hawkes, Jeff A; Connelly, Douglas P; Pearce, David; Linse, Katrin

    2015-01-01

    We analyzed the diversity of bacterial epibionts and trophic ecology of a new species of Kiwa yeti crab discovered at two hydrothermal vent fields (E2 and E9) on the East Scotia Ridge (ESR) in the Southern Ocean using a combination of 454 pyrosequencing, Sanger sequencing, and stable isotope analysis. The Kiwa epibiont communities were dominated by Epsilon- and Gammaproteobacteria. About 454 sequencing of the epibionts on 15 individual Kiwa specimen revealed large regional differences between the two hydrothermal vent fields: at E2, the bacterial community on the Kiwa ventral setae was dominated (up to 75%) by Gammaproteobacteria, whereas at E9 Epsilonproteobacteria dominated (up to 98%). Carbon stable isotope analysis of both Kiwa and the bacterial epibionts also showed distinct differences between E2 and E9 in mean and variability. Both stable isotope and sequence data suggest a dominance of different carbon fixation pathways of the epibiont communities at the two vent fields. At E2, epibionts were putatively fixing carbon via the Calvin-Benson-Bassham and reverse tricarboxylic acid cycle, while at E9 the reverse tricarboxylic acid cycle dominated. Co-varying epibiont diversity and isotope values at E2 and E9 also present further support for the hypothesis that epibionts serve as a food source for Kiwa. PMID:25515351

  7. Bacillus anthracis physiology and genetics.

    PubMed

    Koehler, Theresa M

    2009-12-01

    Bacillus anthracis is a member of the Bacillus cereus group species (also known as the "group 1 bacilli"), a collection of Gram-positive spore-forming soil bacteria that are non-fastidious facultative anaerobes with very similar growth characteristics and natural genetic exchange systems. Despite their close physiology and genetics, the B. cereus group species exhibit certain species-specific phenotypes, some of which are related to pathogenicity. B. anthracis is the etiologic agent of anthrax. Vegetative cells of B. anthracis produce anthrax toxin proteins and a poly-d-glutamic acid capsule during infection of mammalian hosts and when cultured in conditions considered to mimic the host environment. The genes associated with toxin and capsule synthesis are located on the B. anthracis plasmids, pXO1 and pXO2, respectively. Although plasmid content is considered a defining feature of the species, pXO1- and pXO2-like plasmids have been identified in strains that more closely resemble other members of the B. cereus group. The developmental nature of B. anthracis and its pathogenic (mammalian host) and environmental (soil) lifestyles of make it an interesting model for study of niche-specific bacterial gene expression and physiology. PMID:19654018

  8. Physiologic time: A hypothesis

    NASA Astrophysics Data System (ADS)

    West, Damien; West, Bruce J.

    2013-06-01

    The scaling of respiratory metabolism with body size in animals is considered by many to be a fundamental law of nature. One apparent consequence of this law is the scaling of physiologic time with body size, implying that physiologic time is separate and distinct from clock time. Physiologic time is manifest in allometry relations for lifespans, cardiac cycles, blood volume circulation, respiratory cycle, along with a number of other physiologic phenomena. Herein we present a theory of physiologic time that explains the allometry relation between time and total body mass averages as entailed by the hypothesis that the fluctuations in the total body mass are described by a scaling probability density.

  9. Community Links

    ERIC Educational Resources Information Center

    Nelson, Mary

    1975-01-01

    At Moraine Valley Community College (Illinois), a chain of events, programs, activities, and services has linked the college and community in such areas as fine arts, ethnic groups, public services, community action, community service, and community education. (Author/NHM)

  10. Anatomy and Physiology of the Speech Mechanism.

    ERIC Educational Resources Information Center

    Sheets, Boyd V.

    This monograph on the anatomical and physiological aspects of the speech mechanism stresses the importance of a general understanding of the process of verbal communication. Contents include "Positions of the Body,""Basic Concepts Linked with the Speech Mechanism,""The Nervous System,""The Respiratory System--Sound-Power Source,""The…

  11. Link Analysis

    NASA Astrophysics Data System (ADS)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  12. Brown adipose tissue: physiological function and evolutionary significance.

    PubMed

    Oelkrug, R; Polymeropoulos, E T; Jastroch, M

    2015-08-01

    In modern eutherian (placental) mammals, brown adipose tissue (BAT) evolved as a specialized thermogenic organ that is responsible for adaptive non-shivering thermogenesis (NST). For NST, energy metabolism of BAT mitochondria is increased by activation of uncoupling protein 1 (UCP1), which dissipates the proton motive force as heat. Despite the presence of UCP1 orthologues prior to the divergence of teleost fish and mammalian lineages, UCP1's significance for thermogenic adipose tissue emerged at later evolutionary stages. Recent studies on the presence of BAT in metatherians (marsupials) and eutherians of the afrotherian clade provide novel insights into the evolution of adaptive NST in mammals. In particular studies on the 'protoendothermic' lesser hedgehog tenrec (Afrotheria) suggest an evolutionary scenario linking BAT to the onset of eutherian endothermy. Here, we review the physiological function and distribution of BAT in an evolutionary context by focusing on the latest research on phylogenetically distinct species. PMID:25966796

  13. Nitrogen chemistry and lung physiology.

    PubMed

    Marozkina, Nadzeya V; Gaston, Benjamin

    2015-01-01

    The versatile chemistry of nitrogen is important to pulmonary physiology. Indeed, almost all redox forms of nitrogen are relevant to pulmonary physiology and to pathophysiology. Here we review the relevance to pulmonary biology of (a) elemental nitrogen; (b) reduced forms of nitrogen such as amines, ammonia, and hydroxylamine; and (c) oxidized forms of nitrogen such as the nitroxyl anion, the nitric oxide free radical, and S-nitrosothiols. Our focus is on oxidized nitrogen in the form of S-nitrosothiol bond-containing species, which are now appreciated to be important to every type of cell-signaling process in the lung. We also review potential clinical applications of nitrogen oxide biochemistry. These principles are being translated into clinical practice as diagnostic techniques and therapies for a range of pulmonary diseases including asthma, cystic fibrosis, adult respiratory distress syndrome, primary ciliary dyskinesia, and pulmonary hypertension. PMID:25668023

  14. COMPARATIVE GUT PHYSIOLOGY SYMPOSIUM: Comparative physiology of digestion.

    PubMed

    Furness, J B; Cottrell, J J; Bravo, D M

    2015-02-01

    The digestive systems of all species have been shaped by environmental pressures over long evolutionary time spans. Nevertheless, all digestive systems must achieve the same end points, the ingestion of biological material and its conversion to molecules that serve as energy substrates and structural components of tissues. A range of strategies to extract nutrients, including for animals reliant primarily on foregut fermentation, hindgut fermentation, and enzymatic degradation, have evolved. Moreover, animals have adapted to different foodstuffs as herbivores (including frugivores, folivores, granivores, etc.), carnivores, and omnivores. We present evidence that humans have diverged from other omnivores because of the long history of consumption of cooked or otherwise prepared food. We consider them to be cucinivores. We present examples to illustrate that the range of foodstuffs that can be efficiently assimilated by each group or species is limited and is different from that of other groups or species. Differences are reflected in alimentary tract morphology. The digestive systems of each group and of species within the groups are adaptable, with constraints determined by individual digestive physiology. Although overall digestive strategies and systems differ, the building blocks for digestion are remarkably similar. All vertebrates have muscular tubular tracts lined with a single layer of epithelial cells for most of the length, use closely related digestive enzymes and transporters, and control the digestive process through similar hormones and similarly organized nerve pathways. Extrapolations among species that are widely separated in their digestive physiologies are possible when the basis for extrapolation is carefully considered. Divergence is greatest at organ or organismal levels, and similarities are greatest at the cell and molecular level. PMID:26020739

  15. Chewing over physiology integration.

    PubMed

    Abdulkader, Fernando; Azevedo-Martins, Anna Karenina; Miranda, Manoel de Arcisio; Brunaldi, Kellen

    2005-03-01

    An important challenge for both students and teachers of physiology is to integrate the different areas in which physiological knowledge is didactically divided. In developing countries, such an issue is even more demanding, because budget restrictions often affect the physiology program with laboratory classes being the first on the list when it comes to cuts in expenses. With the aim of addressing this kind of problem, the graduate students of our department organized a physiology summer course offered to undergraduate students. The objective was to present the different physiological systems in an integrated fashion. The strategy pursued was to plan laboratory classes whose experimental results were the basis for the relevant theoretical discussions. The subject we developed to illustrate physiology integration was the study of factors influencing salivary secretion. PMID:15718383

  16. The physiology of invasive plants in low-resource environments

    PubMed Central

    Funk, Jennifer L.

    2013-01-01

    While invasive plant species primarily occur in disturbed, high-resource environments, many species have invaded ecosystems characterized by low nutrient, water, and light availability. Species adapted to low-resource systems often display traits associated with resource conservation, such as slow growth, high tissue longevity, and resource-use efficiency. This contrasts with our general understanding of invasive species physiology derived primarily from studies in high-resource environments. These studies suggest that invasive species succeed through high resource acquisition. This review examines physiological and morphological traits of native and invasive species in low-resource environments. Existing data support the idea that species invading low-resource environments possess traits associated with resource acquisition, resource conservation or both. Disturbance and climate change are affecting resource availability in many ecosystems, and understanding physiological differences between native and invasive species may suggest ways to restore invaded ecosystems. PMID:27293610

  17. Teaching Acid/Base Physiology in the Laboratory

    ERIC Educational Resources Information Center

    Friis, Ulla G.; Plovsing, Ronni; Hansen, Klaus; Laursen, Bent G.; Wallstedt, Birgitta

    2010-01-01

    Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory exercise in acid/base physiology that would provide…

  18. Linked Systems.

    ERIC Educational Resources Information Center

    Association of Research Libraries, Washington, DC.

    Three papers are compiled here for research library directors: (1) "Background: Open Systems Interconnection," in which David F. Bishop provides fundamental background information to explain the concept of the emerging technology of linked systems and open systems interconnection--i.e., an agreed upon standard set of conventions or rules that,…

  19. Impact of microbial inoculation on biomass accumulation by Sulla carnosa provenances, and in regulating nutrition, physiological and antioxidant activities of this species under non-saline and saline conditions.

    PubMed

    Hidri, R; Barea, J M; Mahmoud, O Metoui-Ben; Abdelly, C; Azcón, Rosario

    2016-08-20

    Bacteria (Pseudomonas sp. and Bacillus sp.) and/or the arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices were able to improve growth, physiological and biochemical characteristics of four Sulla carnosa Desf. provenances (Sidi khlif, Thelja, Kalbia and Kerker) from Tunisia under both saline and non-saline conditions. S. carnosa is a salt-tolerant legume plant, native from North Africa. The intrinsic bacterial characteristics evidenced the fitness of these bacteria to support salt stress and to stimulate plant growth. Bacillus sp. produced more indol acetic acid (IAA) than Pseudomonas sp. and showed a great surviving capacity under salt conditions supporting its capacity to improve plant growth under stress conditions. The microorganisms applied also have a different potential to increase the nutritional and related plant growth parameters. It is noticeable that some provenances reached the highest level of growth when inoculated with Bacillus sp. in Sidi khlif or by Bacillus plus AMF in Kalbia, which increased shoot by 318% and root by 774%. In contrast, in Thelja and Kerker the impact of the test microorganisms was mainly evidenced at increasing nutritional and physiological functions. Salinity reduced some growth and physiological variables as stomatal conductance, photosynthetic pigments and photosynthetic efficiency and increased electrolyte leakage. However, the microbial inoculants compensated these detrimental effects in a degree depending on the S. carnosa provenance. These microorganisms also orchestrate antioxidant activities involved in adaptative responses in S. carnosa provenances. The intrinsic ability of inoculants allow us to select the provenance/microorganism combination which maximizes S. carnosa growth, nutrition and physiological/biochemical responses under salt and non-salt conditions. The results obtained support that the target microbial inocula are beneficial for the ecological stability if this Mediterranean legume. PMID:27393918

  20. Genetic, molecular and physiological basis of variation in Drosophila gut immunocompetence

    PubMed Central

    Bou Sleiman, Maroun S.; Osman, Dani; Massouras, Andreas; Hoffmann, Ary A.; Lemaitre, Bruno; Deplancke, Bart

    2015-01-01

    Gut immunocompetence involves immune, stress and regenerative processes. To investigate the determinants underlying inter-individual variation in gut immunocompetence, we perform enteric infection of 140 Drosophila lines with the entomopathogenic bacterium Pseudomonas entomophila and observe extensive variation in survival. Using genome-wide association analysis, we identify several novel immune modulators. Transcriptional profiling further shows that the intestinal molecular state differs between resistant and susceptible lines, already before infection, with one transcriptional module involving genes linked to reactive oxygen species (ROS) metabolism contributing to this difference. This genetic and molecular variation is physiologically manifested in lower ROS activity, lower susceptibility to ROS-inducing agent, faster pathogen clearance and higher stem cell activity in resistant versus susceptible lines. This study provides novel insights into the determinants underlying population-level variability in gut immunocompetence, revealing how relatively minor, but systematic genetic and transcriptional variation can mediate overt physiological differences that determine enteric infection susceptibility. PMID:26213329

  1. Microbial physiology vol. 29

    SciTech Connect

    Rose, A.H. ); Tempest, D.W. )

    1988-01-01

    This book contains the following chapters: Hydrogen metabolism in Rhizobium: energetics, regulation, enzymology and genetics; The physiology and biochemistry of pili; Carboxysomes and ribulose bisphosphate carboxylase/oxygenase; Archaebacteria: the comparative enzymology of their central metabolic pathways; and Physiology of lipoteichoic acids in bacteria.

  2. Phun Week: Understanding Physiology

    ERIC Educational Resources Information Center

    Limson, Mel; Matyas, Marsha Lakes

    2009-01-01

    Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…

  3. Membrane lipid unsaturation as physiological adaptation to animal longevity

    PubMed Central

    Naudí, Alba; Jové, Mariona; Ayala, Victòria; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

    2013-01-01

    The appearance of oxygen in the terrestrial atmosphere represented an important selective pressure for ancestral living organisms and contributed toward setting up the pace of evolutionary changes in structural and functional systems. The evolution of using oxygen for efficient energy production served as a driving force for the evolution of complex organisms. The redox reactions associated with its use were, however, responsible for the production of reactive species (derived from oxygen and lipids) with damaging effects due to oxidative chemical modifications of essential cellular components. Consequently, aerobic life required the emergence and selection of antioxidant defense systems. As a result, a high diversity in molecular and structural antioxidant defenses evolved. In the following paragraphs, we analyze the adaptation of biological membranes as a dynamic structural defense against reactive species evolved by animals. In particular, our goal is to describe the physiological mechanisms underlying the structural adaptation of cellular membranes to oxidative stress and to explain the meaning of this adaptive mechanism, and to review the state of the art about the link between membrane composition and longevity of animal species. PMID:24381560

  4. Membrane lipid unsaturation as physiological adaptation to animal longevity.

    PubMed

    Naudí, Alba; Jové, Mariona; Ayala, Victòria; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

    2013-01-01

    The appearance of oxygen in the terrestrial atmosphere represented an important selective pressure for ancestral living organisms and contributed toward setting up the pace of evolutionary changes in structural and functional systems. The evolution of using oxygen for efficient energy production served as a driving force for the evolution of complex organisms. The redox reactions associated with its use were, however, responsible for the production of reactive species (derived from oxygen and lipids) with damaging effects due to oxidative chemical modifications of essential cellular components. Consequently, aerobic life required the emergence and selection of antioxidant defense systems. As a result, a high diversity in molecular and structural antioxidant defenses evolved. In the following paragraphs, we analyze the adaptation of biological membranes as a dynamic structural defense against reactive species evolved by animals. In particular, our goal is to describe the physiological mechanisms underlying the structural adaptation of cellular membranes to oxidative stress and to explain the meaning of this adaptive mechanism, and to review the state of the art about the link between membrane composition and longevity of animal species. PMID:24381560

  5. Physiological polyamines: simple primordial stress molecules

    PubMed Central

    Rhee, H J; Kim, Eui-Jin; Lee, J K

    2007-01-01

    Abstract Physiological polyamines are ubiquitous polycations with pleiotropic biochemical activities, including regulation of gene expression, cell proliferation and modulation of cell signalling. Reports that the polyamines with cytoprotective activities were induced by diverse stresses raised the hypothesis that physiological polyamines may play a role in inducing stress response. In a wide range of organisms, physiological polyamines were not only induced by diverse stresses, such as reactive oxygen species (ROS), heat, ultraviolet (UV) and psychiatric stress but were able to confer beneficial effects for survival. Recent biochemical and genetic evidences show that polyamines can function as an ROS scavenger, acid tolerance factor and chemical chaperone, and positive regulators for expression of stress response genes which may explain their protective functions against diverse stresses. Taken together, these data suggest that physiological polyamines can function as primordial stress molecules in bacteria, plants and mammals, and may play an essential role in regulation of pathogen-host interactions. PMID:17760833

  6. Seed dormancy in alpine species

    PubMed Central

    Schwienbacher, Erich; Navarro-Cano, Jose Antonio; Neuner, Gilbert; Erschbamer, Brigitta

    2011-01-01

    In alpine species the classification of the various mechanisms underlying seed dormancy has been rather questionable and controversial. Thus, we investigated 28 alpine species to evaluate the prevailing types of dormancy. Embryo type and water impermeability of seed coats gave an indication of the potential seed dormancy class. To ascertain the actual dormancy class and level, we performed germination experiments comparing the behavior of seeds without storage, after cold-dry storage, after cold-wet storage, and scarification. We also tested the light requirement for germination in some species. Germination behavior was characterized using the final germination percentage and the mean germination time. Considering the effects of the pretreatments, a refined classification of the prevailing dormancy types was constructed based on the results of our pretreatments. Only two out of the 28 species that we evaluated had predominantly non-dormant seeds. Physiological dormancy was prevalent in 20 species, with deep physiological dormancy being the most abundant, followed by non-deep and intermediate physiological dormancy. Seeds of four species with underdeveloped embryos were assigned to the morphophysiologial dormancy class. An impermeable seed coat was identified in two species, with no additional physiological germination block. We defined these species as having physical dormancy. Light promoted the germination of seeds without storage in all but one species with physiological dormancy. In species with physical dormancy, light responses were of minor importance. We discuss our new classification in the context of former germination studies and draw implications for the timing of germination in the field. PMID:24415831

  7. Mechanosignaling in the vasculature: emerging concepts in sensing, transduction and physiological responses

    PubMed Central

    Fujiwara, Keigi; Pérez, Néstor Gustavo; Ushio-Fukai, Masuko; Fisher, Aron B.

    2015-01-01

    Cells are constantly exposed to mechanical forces that play a role in modulating cellular structure and function. The cardiovascular system experiences physical forces in the form of shear stress and stretch associated with blood flow and contraction, respectively. These forces are sensed by endothelial cells and cardiomyocytes and lead to responses that control vascular and cardiac homeostasis. This was highlighted at the Pan American Physiological Society meeting at Iguassu Falls, Brazil, in a symposium titled “Mechanosignaling in the Vasculature.” This symposium presented recent research that showed the existence of a vital link between mechanosensing and downstream redox sensitive signaling cascades. This link helps to transduce and transmit the physical force into an observable physiological response. The speakers showcased how mechanosensors such as ion channels, membrane receptor kinases, adhesion molecules, and other cellular components transduce the force via redox signals (such as reactive oxygen species and nitric oxide) to receptors (transcription factors, growth factors, etc.). Receptor activated pathways then lead to cellular responses including cellular proliferation, contraction, and remodeling. These responses have major relevance to the physiology and pathophysiology of various cardiovascular diseases. Thus an understanding of the complex series of events, from the initial sensing through the final response, is essential for progress in this field. Overall, this symposium addressed some important emerging concepts in the field of mechanosignaling and the eventual pathophysiological responses. PMID:25862828

  8. The p-eIF2α/ATF4 pathway links endoplasmic reticulum stress to autophagy following the production of reactive oxygen species in mouse spermatocyte-derived cells exposed to dibutyl phthalate.

    PubMed

    Zhang, Guowei; Ling, Xi; Liu, Kaijun; Wang, Zhi; Zou, Peng; Gao, Jianfang; Cao, Jia; Ao, Lin

    2016-07-01

    Dibutyl phthalate (DBP) is a widely used plasticizer that has been shown to induce germ cell apoptosis-related testicular atrophy and cause reproductive toxicity. Our previous results indicated that endoplasmic reticulum (ER) stress-activated autophagy served as a self-defense mechanism against DBP-induced germ cell apoptosis. However, the specific pathways that link ER stress and autophagy remain unclear. Here, we showed that exposure to DBP enhanced autophagic flux in mouse spermatocyte-derived GC-2 cells and that the eukaryotic translation initiation factor 2/activating transcription factor 4 pathway mediated ER stress-related autophagy independent of the mTOR and Beclin-1 pathways. Moreover, we demonstrated that DBP treatment led to the generation of reactive oxygen species (ROS) and that the inhibition of ROS by melatonin abrogated both ER stress and autophagy. The results indicated that excessive ROS production might be involved in DBP-induced ER stress and autophagy in GC-2 cells. Thus, ROS may serve as upstream mediators of ER stress and autophagy in DBP-treated GC-2 cells. PMID:27002192

  9. Assessing physiological tipping points in response to ocean acidification

    NASA Astrophysics Data System (ADS)

    Dupont, S. T.; Dorey, N.; Lançon, P.; Thorndyke, M. S.

    2011-12-01

    rate is decreased. However, the intensity of the impact on the growth rate is depending on the tested pH. When pH is 7.3 or higher, only a small delay in development is observed with no effect on larval morphology (phenotypic plasticity). When the pH is lower than 7.3, the impact is more severe together with major developmental abnormalities. At pH 6.5, the development is totally arrested. The link between a species physiological tipping point and environmental variability will be discussed.

  10. Linking physiology and gene expression: peanut response to abiotic stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The future of crop production in the U.S., as well as in other areas of the world, will rely upon the crop’s ability to yield under decreased water availability and oftentimes critical heat stress. Our group has initiated research in the west Texas peanut production region investigating the effects ...

  11. Physiological correlates of urbanization in a desert songbird.

    PubMed

    Giraudeau, Mathieu; McGraw, Kevin J

    2014-10-01

    Rapid worldwide urbanization is creating novel environments to which animals must adapt, a topic of growing interest for biologists. Studies of how organisms are affected by cities historically centered on large-scale censusing of populations, but recent investigations have considered finer-scaled, urban-rural differences among individuals and species in their behavior, morphology, and physiology, specifically as they relate to urban stress. A number of factors (e.g., corticosterone (CORT)-related stress response) may contribute to the degree of stress experienced by animals living under urban versus natural conditions, but several physiological variables have yet to be considered together in a large-scale assessment. Here, in a widespread species of desert passerine (the house finch, Haemorhous mexicanus), we quantified variation in plasma oxidative stress, plasma concentrations of vitamins and carotenoids, and body-mass of males in three successive seasons (winter, spring, and late summer/early fall) along an urban-rural gradient in Phoenix, Arizona, USA. We found that degree of urbanization was: (1) negatively related to circulating vitamin A concentrations in winter, (2) positively correlated with body-mass during spring, and (3) negatively associated with plasma concentrations of two carotenoids: zeaxanthin (during breeding) and 3-hydroxy-echinenone (3HE) (during molting). The striking link between 3HE levels and urbanization is consistent with previous research showing that urban songbirds have lower carotenoid levels and faded plumage; our finding is the first to implicate specific effects on a metabolically derived carotenoid for coloration. The fact that we observed only season-specific links between urbanization and indicators of quality in finches suggests that (at least for these metrics) there are no strong, lasting urban pressures imposed on finch physiology over the year. Interestingly, we found that a metric of plasma oxidative stress (lipid

  12. A PC-based graphical simulator for physiological pharmacokinetic models.

    PubMed

    Wada, D R; Stanski, D R; Ebling, W F

    1995-04-01

    Since many intravenous anesthetic drugs alter blood flows, physiologically-based pharmacokinetic models describing drug disposition may be time-varying. Using the commercially available programming software MATLAB, a platform to simulate time-varying physiological pharmacokinetic models was developed. The platform is based upon a library of pharmacokinetic blocks which mimic physiological structure. The blocks can be linked together flexibly to form models for different drugs. Because of MATLAB's additional numerical capabilities (e.g. non-linear optimization), the platform provides a complete graphical microcomputer-based tool for physiologic pharmacokinetic modeling. PMID:7656558

  13. Reproduction, physiology and biochemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter summarizes fundamental knowledge and recent discoveries about the reproduction, physiology and biochemistry of plant-parasitic nematodes. Various types of reproduction are reviewed, including sexual reproduction and mitotic and meiotic parthenogenesis. Although much is known about the p...

  14. The Physiologically Difficult Airway.

    PubMed

    Mosier, Jarrod M; Joshi, Raj; Hypes, Cameron; Pacheco, Garrett; Valenzuela, Terence; Sakles, John C

    2015-12-01

    Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation. PMID:26759664

  15. Endogenous Pyrogen Physiology.

    ERIC Educational Resources Information Center

    Beisel, William R.

    1980-01-01

    Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

  16. The Physiologically Difficult Airway

    PubMed Central

    Mosier, Jarrod M.; Joshi, Raj; Hypes, Cameron; Pacheco, Garrett; Valenzuela, Terence; Sakles, John C.

    2015-01-01

    Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation. PMID:26759664

  17. Physiological Stress in Koala Populations near the Arid Edge of Their Distribution

    PubMed Central

    Davies, Nicole Ashley; Gramotnev, Galina; McAlpine, Clive; Seabrook, Leonie; Baxter, Greg; Lunney, Daniel; Rhodes, Jonathan R.; Bradley, Adrian

    2013-01-01

    Recent research has shown that the ecology of stress has hitherto been neglected, but it is in fact an important influence on the distribution and numbers of wild vertebrates. Environmental changes have the potential to cause physiological stress that can affect population dynamics. Detailed information on the influence of environmental variables on glucocorticoid levels (a measure of stress) at the trailing edge of a species’ distribution can highlight stressors that potentially threaten species and thereby help explain how environmental challenges, such as climate change, will affect the survival of these populations. Rainfall determines leaf moisture and/or nutritional content, which in turn impacts on cortisol concentrations. We show that higher faecal cortisol metabolite (FCM) levels in koala populations at the trailing arid edge of their range in southwestern Queensland are associated with lower rainfall levels (especially rainfall from the previous two months), indicating an increase in physiological stress when moisture levels are low. These results show that koalas at the semi-arid, inland edge of their geographic range, will fail to cope with increasing aridity from climate change. The results demonstrate the importance of integrating physiological assessments into ecological studies to identify stressors that have the potential to compromise the long-term survival of threatened species. This finding points to the need for research to link these stressors to demographic decline to ensure a more comprehensive understanding of species’ responses to climate change. PMID:24265749

  18. The use of haemoglobin concentrations to assess physiological condition in birds: a review

    PubMed Central

    Minias, Piotr

    2015-01-01

    Total blood haemoglobin concentration is increasingly being used to assess physiological condition in wild birds, although it has not been explicitly recognized how reliably this parameter reflects different components of individual quality. Thus, I reviewed over 120 published studies linking variation in haemoglobin concentrations to different measures of condition and other phenotypic or ecological traits. In most of the studied avian species, haemoglobin concentrations were positively correlated with other commonly used indices of condition, such as body mass and fat loads, as well as with quality of the diet. Also, chick haemoglobin concentrations reliably reflected the intensity of nest infestation by parasitic arthropods, and haemoglobin was suggested to reflect parasitism by haematophagous ectoparasites much more precisely than haematocrit. There was also some evidence for the negative effect of helminths on haemoglobin levels in adult birds. Finally, haemoglobin concentrations were found to correlate with such fitness-related traits as timing of arrival at breeding grounds, timing of breeding, egg size, developmental stability and habitat quality, although these relationships were not always consistent between species. In consequence, I recommend the total blood haemoglobin concentration as a relatively robust indicator of physiological condition in birds, although this parameter is also strongly affected by age, season and the process of moult. Thus, researchers are advised to control fully for these confounding effects while using haemoglobin concentrations as a proxy of physiological condition in both experimental and field studies on birds. PMID:27293692

  19. Physiological ecology meets climate change

    PubMed Central

    Bozinovic, Francisco; Pörtner, Hans-Otto

    2015-01-01

    In this article, we pointed out that understanding the physiology of differential climate change effects on organisms is one of the many urgent challenges faced in ecology and evolutionary biology. We explore how physiological ecology can contribute to a holistic view of climate change impacts on organisms and ecosystems and their evolutionary responses. We suggest that theoretical and experimental efforts not only need to improve our understanding of thermal limits to organisms, but also to consider multiple stressors both on land and in the oceans. As an example, we discuss recent efforts to understand the effects of various global change drivers on aquatic ectotherms in the field that led to the development of the concept of oxygen and capacity limited thermal tolerance (OCLTT) as a framework integrating various drivers and linking organisational levels from ecosystem to organism, tissue, cell, and molecules. We suggest seven core objectives of a comprehensive research program comprising the interplay among physiological, ecological, and evolutionary approaches for both aquatic and terrestrial organisms. While studies of individual aspects are already underway in many laboratories worldwide, integration of these findings into conceptual frameworks is needed not only within one organism group such as animals but also across organism domains such as Archaea, Bacteria, and Eukarya. Indeed, development of unifying concepts is relevant for interpreting existing and future findings in a coherent way and for projecting the future ecological and evolutionary effects of climate change on functional biodiversity. We also suggest that OCLTT may in the end and from an evolutionary point of view, be able to explain the limited thermal tolerance of metazoans when compared to other organisms. PMID:25798220

  20. Physiological ecology meets climate change.

    PubMed

    Bozinovic, Francisco; Pörtner, Hans-Otto

    2015-03-01

    In this article, we pointed out that understanding the physiology of differential climate change effects on organisms is one of the many urgent challenges faced in ecology and evolutionary biology. We explore how physiological ecology can contribute to a holistic view of climate change impacts on organisms and ecosystems and their evolutionary responses. We suggest that theoretical and experimental efforts not only need to improve our understanding of thermal limits to organisms, but also to consider multiple stressors both on land and in the oceans. As an example, we discuss recent efforts to understand the effects of various global change drivers on aquatic ectotherms in the field that led to the development of the concept of oxygen and capacity limited thermal tolerance (OCLTT) as a framework integrating various drivers and linking organisational levels from ecosystem to organism, tissue, cell, and molecules. We suggest seven core objectives of a comprehensive research program comprising the interplay among physiological, ecological, and evolutionary approaches for both aquatic and terrestrial organisms. While studies of individual aspects are already underway in many laboratories worldwide, integration of these findings into conceptual frameworks is needed not only within one organism group such as animals but also across organism domains such as Archaea, Bacteria, and Eukarya. Indeed, development of unifying concepts is relevant for interpreting existing and future findings in a coherent way and for projecting the future ecological and evolutionary effects of climate change on functional biodiversity. We also suggest that OCLTT may in the end and from an evolutionary point of view, be able to explain the limited thermal tolerance of metazoans when compared to other organisms. PMID:25798220

  1. Metabolic Physiology in Pregnancy.

    PubMed

    Meo, Sultan Ayoub; Hassain, Asim

    2016-09-01

    The metabolic physiology during pregnancy is unique in the life of women. This change is a normal physiological adaptation to better accommodate the foetal growth and provides adequate blood, nutrition and oxygen. The metabolic changes prepare the mother\\'s body for pregnancy, childbirth and lactation. Early gestational period is considered as an anabolic phase, in which female body stores nutrients, enhance insulin sensitivity to encounter the maternal and feto-placental demands of late gestation and lactation. However, late gestational period is better named as a catabolic phase with reduced insulin sensitivity. The placenta plays a role as a sensor between mother and foetus physiology and acclimatizes the needs of the foetus to adequate growth and development. During pregnancy the female body changes its physiological and homeostatic mechanisms to meet the physiological needs of the foetus. However, if the maternal metabolic physiology during pregnancy is disturbed, it can cause hormonal imbalance, fat accumulation, decreased insulin sensitivity, increased insulin resistance and even gestational diabetes mellitus. PMID:27582161

  2. Cassava biology and physiology.

    PubMed

    El-Sharkawy, Mabrouk A

    2004-11-01

    Cassava or manioc (Manihot esculenta Crantz), a perennial shrub of the New World, currently is the sixth world food crop for more than 500 million people in tropical and sub-tropical Africa, Asia and Latin America. It is cultivated mainly by resource-limited small farmers for its starchy roots, which are used as human food either fresh when low in cyanogens or in many processed forms and products, mostly starch, flour, and for animal feed. Because of its inherent tolerance to stressful environments, where other food crops would fail, it is often considered a food-security source against famine, requiring minimal care. Under optimal environmental conditions, it compares favorably in production of energy with most other major staple food crops due to its high yield potential. Recent research at the Centro Internacional de Agricultura Tropical (CIAT) in Colombia has demonstrated the ability of cassava to assimilate carbon at very high rates under high levels of humidity, temperature and solar radiation,which correlates with productivity across all environments whether dry or humid. When grown on very poor soils under prolonged drought for more than 6 months, the crop reduce both its leaf canopy and transpiration water loss, but its attached leaves remain photosynthetically active, though at greatly reduced rates. The main physiological mechanism underlying such a remarkable tolerance to drought was rapid stomatal closure under both atmospheric and edaphic water stress, protecting the leaf against dehydration while the plant depletes available soil water slowly during long dry periods. This drought tolerance mechanism leads to high crop water use efficiency values. Although the cassava fine root system is sparse, compared to other crops, it can penetrate below 2 m soil,thus enabling the crop to exploit deep water if available. Leaves of cassava and wild Manihot possess elevated activities of the C4 enzyme PEP carboxylase but lack the leaf Kranz anatomy typical of C4

  3. Good vibrations: "sirens," soundscapes, and physiology.

    PubMed

    Plock, Vike Martina

    2008-01-01

    This article establishes Joyce's ongoing interest in psychoacoustics and illustrates how much he drew, in the writing of the "Sirens" episode, on nineteenth-century sound experiments that were developed by the German physician Hermann von Helmholtz. It argues that Joyce consciously referenced nineteenth-century sound theories to explore the link between the emotional and sensory experience of music and the physical and physiological components of sound perception. PMID:20836272

  4. Genetics and the physiological ecology of conifers

    SciTech Connect

    Mitton, J.B.

    1995-07-01

    Natural selection acts on the diversity of genotypes, adapting populations to their specific environments and driving evolution in response to changes in climate. Genetically based differences in physiology and demography adapt species to alternate environments and produce, along with historical accidents, the present distribution of species. The sorting of conifer species by elevation is so marked that conifers help to define plant communities arranged in elevational bands in the Rocky Mountains. For these reasons, a genetic perspective is necessary to appreciate the evolution of ecophysiological patterns in the coniferous forests of the Rocky Mountains. The fascinating natural history and the economic importance of western conifers have stimulated numerous studies of their ecology, ecological genetics, and geographic variation. These studies yield some generalizations, and present some puzzling contradictions. This chapter focuses on the genetic variability associated with the physiological differences among genotypes in Rocky Mountain conifers. Variation among genotypes in survival, growth, and resistance to herbivores is used to illustrate genetically based differences in physiology, and to suggest the mechanistic studies needed to understand the relationships between genetic and physiological variation.

  5. Transatlantic link

    NASA Astrophysics Data System (ADS)

    (left) European Geophysical Society (EGS) President Rolf Meissner at AGU Headquarters with (center) Executive Director Fred Spilhaus and (right) Foreign Secretary Juan Roederer. Meissner attended the meeting of AGU's Committee on International Participation (CIP) on February 26, 1988. At that meeting, specific ways of fostering close links between AGU and EGS were discussed.A few weeks later, Roederer and AGU staff, working with EGS Secretary-General Arne Richter at the EGS meeting in Bologna, Italy, March 21-25, planned details of the establishment of an AGU office in Europe. The Copernicus Gesellschaft, a new entity located on the premises of the Max Planck Institute for Aeronomy in Lindau, Federal Republic of Germany, will provide the administrative staff and handle logistics.

  6. Cardiovascular physiology and diseases of amphibians.

    PubMed

    Heinz-Taheny, Kathleen M

    2009-01-01

    The class Amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. The diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). This article provides a review of amphibian cardiovascular anatomy and physiology with discussion of unique species adaptations. In addition, amphibians as cardiovascular animal models and commonly encountered natural diseases are covered. PMID:19131029

  7. Assessing physiological complexity.

    PubMed

    Burggren, W W; Monticino, M G

    2005-09-01

    Physiologists both admire and fear complexity, but we have made relatively few attempts to understand it. Inherently complex systems are more difficult to study and less predictable. However, a deeper understanding of physiological systems can be achieved by modifying experimental design and analysis to account for complexity. We begin this essay with a tour of some mathematical views of complexity. After briefly exploring chaotic systems, information theory and emergent behavior, we reluctantly conclude that, while a mathematical view of complexity provides useful perspectives and some narrowly focused tools, there are too few generally practical take-home messages for physiologists studying complex systems. Consequently, we attempt to provide guidelines as to how complex systems might be best approached by physiologists. After describing complexity based on the sum of a physiological system's structures and processes, we highlight increasingly refined approaches based on the pattern of interactions between structures and processes. We then provide a series of examples illustrating how appreciating physiological complexity can improve physiological research, including choosing experimental models, guiding data collection, improving data interpretations and constructing more rigorous system models. Finally, we conclude with an invitation for physiologists, applied mathematicians and physicists to collaborate on describing, studying and learning from studies of physiological complexity. PMID:16109885

  8. Genetic approaches in comparative and evolutionary physiology.

    PubMed

    Storz, Jay F; Bridgham, Jamie T; Kelly, Scott A; Garland, Theodore

    2015-08-01

    Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. PMID:26041111

  9. Genetic approaches in comparative and evolutionary physiology

    PubMed Central

    Bridgham, Jamie T.; Kelly, Scott A.; Garland, Theodore

    2015-01-01

    Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. PMID:26041111

  10. Human physiology in space

    NASA Technical Reports Server (NTRS)

    Vernikos, J.

    1996-01-01

    The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.

  11. Rainfall seasonality and pest pressure as determinants of tropical tree species' distributions.

    PubMed

    Baltzer, Jennifer L; Davies, Stuart J

    2012-11-01

    Drought and pests are primary abiotic and biotic factors proposed as selective filters acting on species distributions along rainfall gradients in tropical forests and may contribute importantly to species distributional limits, performance, and diversity gradients. Recent research demonstrates linkages between species distributions along rainfall gradients and physiological drought tolerance; corresponding experimental examinations of the contribution of pest pressure to distributional limits and potential interactions between drought and herbivory are limited. This study aims to quantitate differential performance and herbivory as a function of species range limits across a climatic and floristic transition in Southeast Asia. Khao Chong Botanical Garden, Thailand and Pasoh Forest Reserve, Malaysia straddle the Kangar-Pattani Line. A reciprocal transplantation across a seasonality gradient was established using two groups of species ("widespread" taxa whose distributions include seasonally dry forests and "aseasonal" taxa whose distributions are limited to aseasonal forests). Growth, biomass allocation, survival, and herbivory were monitored for 19 months. Systematic differences in performance were a function of species distribution in relation to rainfall seasonality. In aseasonal Pasoh, aseasonal species had both greater growth and survivorship than widespread species. These differences were not a function of differential herbivory as widespread and aseasonal species experienced similar damage in the aseasonal forest. In seasonally dry Khao Chong, widespread species showed higher survivorship than aseasonal species, but these differences were only apparent during drought. We link this differential performance to physiological mechanisms as well as differential tolerance of biotic pressure during drought stress. Systematic decreases in seedling survival in aseasonal taxa during drought corresponded with previously documented physiological differences and may be

  12. Single-ventricle physiology.

    PubMed

    Schwartz, Steven M; Dent, Catherine L; Musa, Ndidi L; Nelson, David P

    2003-07-01

    The patient with single-ventricle physiology presents a significant challenge to the intensive care team at all stages of management. An integrated approach that applies a working knowledge of cardiac anatomy, cardiopulmonary physiology, and the basic principles of intensive care is essential to guide management for each individual patient. This management requires cooperative and constructive involvement of surgeons, cardiologists, and intensivists, as well as a nursing and respiratory care team experienced in the management of single-ventricle patients. The outcome of each stage of palliation for single-ventricle lesions should continue to improve as new ideas are developed and as older ideas are subjected to rigorous scientific analyses. PMID:12848312

  13. Specifications Physiological Monitoring System

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The operation of a physiological monitoring system (PMS) is described. Specifications were established for performance, design, interface, and test requirements. The PMS is a compact, microprocessor-based system, which can be worn in a pack on the body or may be mounted on a Spacelab rack or other appropriate structure. It consists of two modules, the Data Control Unit (DCU) and the Remote Control/Display Unit (RCDU). Its purpose is to collect and distribute data from physiological experiments in the Spacelab and in the Orbiter.

  14. Prediction of a potentially effective dose in humans for BAY 60–5521, a potent inhibitor of cholesteryl ester transfer protein (CETP) by allometric species scaling and combined pharmacodynamic and physiologically-based pharmacokinetic modelling

    PubMed Central

    Weber, Olaf; Willmann, Stefan; Bischoff, Hilmar; Li, Volkhart; Vakalopoulos, Alexandros; Lustig, Klemens; Hafner, Frank-Thorsten; Heinig, Roland; Schmeck, Carsten; Buehner, Klaus

    2012-01-01

    AIMS The purpose of this work was to support the prediction of a potentially effective dose for the CETP-inhibitor, BAY 60–5521, in humans. METHODS A combination of allometric scaling of the pharmacokinetics of the CETP-inhibitor BAY 60–5521 with pharmacodynamic studies in CETP-transgenic mice and in human plasma with physiologically-based pharmacokinetic (PBPK) modelling was used to support the selection of the first-in-man dose. RESULTS The PBPK approach predicts a greater extent of distribution for BAY 60–5521 in humans compared with the allometric scaling method as reflected by a larger predicted volume of distribution and longer elimination half-life. The combined approach led to an estimate of a potentially effective dose for BAY 60–5521 of 51 mg in humans. CONCLUSION The approach described in this paper supported the prediction of a potentially effective dose for the CETP-inhibitor BAY 60–5521 in humans. Confirmation of the dose estimate was obtained in a first-in-man study. PMID:21762205

  15. Physiology of Sleep.

    PubMed

    Carley, David W; Farabi, Sarah S

    2016-02-01

    IN BRIEF Far from a simple absence of wakefulness, sleep is an active, regulated, and metabolically distinct state, essential for health and well-being. In this article, the authors review the fundamental anatomy and physiology of sleep and its regulation, with an eye toward interactions between sleep and metabolism. PMID:26912958

  16. Simulated Exercise Physiology Laboratories.

    ERIC Educational Resources Information Center

    Morrow, James R., Jr.; Pivarnik, James M.

    This book consists of a lab manual and computer disks for either Apple or IBM hardware. The lab manual serves as "tour guide" for the learner going through the various lab experiences. The manual contains definitions, proper terminology, and other basic information about physiological principles. It is organized so a step-by-step procedure may be…

  17. Research on gravitational physiology

    NASA Technical Reports Server (NTRS)

    Brown, A. H.; Dahl, A. O.

    1974-01-01

    The topic of gravitational plant physiology was studied through aspects of plant development (in ARABIDOPSIS) and of behavior (in HELIANTHUS) as these were affected by altered g experience. The effect of increased g levels on stem polarity (in COLEUS) was also examined.

  18. Physiology of Breastfeeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This powerpoint presentation summaries physiology of lactation and the impact of a variety of clinical practices on lactation from delivery through weaning. Factors that inhibit lactogenesis stage II are explained, including retained placenta, excess blood loss during delivery, and hypoplastic brea...

  19. Starting Physiology: Bioelectrogenesis

    ERIC Educational Resources Information Center

    Baptista, Vander

    2015-01-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The…

  20. Physiology in microgravity.

    PubMed

    West, J B

    2000-07-01

    Studies of physiology in microgravity are remarkably recent, with almost all the data being obtained in the past 40 years. The first human spaceflight did not take place until 1961. Physiological measurements in connection with the early flights were crude, but, in the past 10 years, an enormous amount of new information has been obtained from experiments on Spacelab. The United States and Soviet/Russian programs have pursued different routes. The US has mainly concentrated on relatively short flights but with highly sophisticated equipment such as is available in Spacelab. In contrast, the Soviet/Russian program concentrated on first the Salyut and then the Mir space stations. These had the advantage of providing information about long-term exposure to microgravity, but the degree of sophistication of the measurements in space was less. It is hoped that the International Space Station will combine the best of both approaches. The most important physiological changes caused by microgravity include bone demineralization, skeletal muscle atrophy, vestibular problems causing space motion sickness, cardiovascular problems resulting in postflight orthostatic intolerance, and reductions in plasma volume and red cell mass. Pulmonary function is greatly altered but apparently not seriously impaired. Space exploration is a new frontier with long-term missions to the moon and Mars not far away. Understanding the physiological changes caused by long-duration microgravity remains a daunting challenge. PMID:10904075

  1. Physiology of lactation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The breast changes in size, shape, and function during puberty, pregnancy, and lactation. The physiology of lactation is reviewed here. The breast is composed of fat and connective tissue that supports a tubuloalveolar structure. During development, anatomic changes involving new lobule formation an...

  2. The Physiology of Motivation.

    ERIC Educational Resources Information Center

    Stellar, Eliot

    1994-01-01

    A theory of the physiology of motivation is presented. The basic assumption is that the amount of motivated behavior is a direct function of the amount of activity in certain excitatory centers of the hypothalamus. Activities of these centers are determined by factors in four general classes. (SLD)

  3. Postharvest storage and physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato storage makes the crop available for consumption or sale over an extended period of time. In this book chapter, the various way that potatoes are stored worldwide are described. The most important physiological defects that occur in storage are reviewed, as are the biochemical pathways of car...

  4. Programmable physiological infusion

    NASA Technical Reports Server (NTRS)

    Howard, W. H.; Young, D. R.; Adachi, R. R. (Inventor)

    1974-01-01

    A programmable physiological infusion device and method are provided wherein a program source, such as a paper tape, is used to actuate an infusion pump in accordance with a desired program. The system is particularly applicable for dispensing calcium in a variety of waveforms.

  5. Pathologic and physiologic phimosis

    PubMed Central

    McGregor, Thomas B.; Pike, John G.; Leonard, Michael P.

    2007-01-01

    OBJECTIVE To review the differences between physiologic and pathologic phimosis, review proper foreskin care, and discuss when it is appropriate to seek consultation regarding a phimotic foreskin. SOURCES OF INFORMATION This paper is based on selected findings from a MEDLINE search for literature on phimosis and circumcision referrals and on our experience at the Children’s Hospital of Eastern Ontario Urology Clinic. MeSH headings used in our MEDLINE search included “phimosis,” “referral and consultation,” and “circumcision.” Most of the available articles about phimosis and foreskin referrals were retrospective reviews and cohort studies (levels II and III evidence). MAIN MESSAGE Phimosis is defined as the inability to retract the foreskin. Differentiating between physiologic and pathologic phimosis is important, as the former is managed conservatively and the latter requires surgical intervention. Great anxiety exists among patients and parentsregarding non-retractile foreskins. Most phimosis referrals seen in pediatric urology clinics are normal physiologically phimotic foreskins. Referrals of patients with physiologic phimosis to urology clinics can create anxiety about the need for surgery among patients and parents, while unnecessarily expanding the waiting list for specialty assessment. Uncircumcised penises require no special care. With normal washing, using soap and water, and gentle retraction during urination and bathing, most foreskins will become retractile over time. CONCLUSION Physiologic phimosis is often seen by family physicians. These patients and their parents require reassurance of normalcy and reinforcement of proper preputial hygiene. Consultation should be sought when evidence of pathologic phimosis is present, as this requires surgical management. PMID:17872680

  6. The Open Physiology workflow: modeling processes over physiology circuitboards of interoperable tissue units

    PubMed Central

    de Bono, Bernard; Safaei, Soroush; Grenon, Pierre; Nickerson, David P.; Alexander, Samuel; Helvensteijn, Michiel; Kok, Joost N.; Kokash, Natallia; Wu, Alan; Yu, Tommy; Hunter, Peter; Baldock, Richard A.

    2015-01-01

    A key challenge for the physiology modeling community is to enable the searching, objective comparison and, ultimately, re-use of models and associated data that are interoperable in terms of their physiological meaning. In this work, we outline the development of a workflow to modularize the simulation of tissue-level processes in physiology. In particular, we show how, via this approach, we can systematically extract, parcellate and annotate tissue histology data to represent component units of tissue function. These functional units are semantically interoperable, in terms of their physiological meaning. In particular, they are interoperable with respect to [i] each other and with respect to [ii] a circuitboard representation of long-range advective routes of fluid flow over which to model long-range molecular exchange between these units. We exemplify this approach through the combination of models for physiology-based pharmacokinetics and pharmacodynamics to quantitatively depict biological mechanisms across multiple scales. Links to the data, models and software components that constitute this workflow are found at http://open-physiology.org/. PMID:25759670

  7. Sex-linked dominant

    MedlinePlus

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... one of the sex chromosomes, which are the X and Y chromosomes. Dominant inheritance occurs when an ...

  8. Sex-linked recessive

    MedlinePlus

    Inheritance - sex-linked recessive; Genetics - sex-linked recessive; X-linked recessive ... X-linked recessive diseases usually occur in males. Males have only one X chromosome. A single recessive ...

  9. Sex-linked dominant

    MedlinePlus

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... type of chromosome that is affected (autosomal or sex chromosome). It also depends on whether the trait ...

  10. Determination of antifungal, biochemical and physiological features of Trichoderma koningiopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trichoderma koningiopsis is a species that has been recently identified and has not yet been published, but is in press. Due to the absence of reported data on this species, antifungal, biochemical and physiological features were analyzed for the Trichoderma koningiopsis strain isolated from root se...

  11. Integrative Physiology of Fasting.

    PubMed

    Secor, Stephen M; Carey, Hannah V

    2016-04-01

    Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting. PMID:27065168

  12. Pigment compositions are linked to the habitat types in dinoflagellates.

    PubMed

    Yamada, Norico; Tanaka, Ayumi; Horiguchi, Takeo

    2015-11-01

    Compared to planktonic species, there is little known about the ecology, physiology, and existence of benthic dinoflagellates living in sandy beach or seafloor environments. In a previous study, we discovered 13(2),17(3)-cyclopheophorbide a enol (cPPB-aE) from sand-dwelling benthic dinoflagellates. This enol had never been detected in phytoplankton despite the fact that it is a chlorophyll a catabolite. We speculated from this discovery that habitat selection might be linked to pigment compositions in dinoflagellates. To test the hypothesis of habitat selection linking to pigment compositions, we conducted extensive analysis of pigments with high performance liquid chromatography (HPLC) for 40 species using 45 strains of dinoflagellates including three habitat types; sand-dwelling benthic forms, tidal pool inhabitants and planktonic species. The 40 dinoflagellates are also able to be distinguished into two types based on their chloroplast origins; red alga-derived secondary chloroplasts and diatom-derived tertiary ones. By plotting the pigments profiles onto three habitats, we noticed that twelve pigments including cPPB-aE were found to occur only in benthic sand-dwelling species of red alga-derived type. The similar tendency was also observed in dinoflagellates with diatom-derived chloroplasts, i.e. additional sixteen pigments including chl c 3 were found only in sand-dwelling forms. This is the first report of the occurrence of chl c 3 in dinoflagellates with diatom-derived chloroplasts. These results clarify that far greater diversity of pigments are produced by the dinoflagellates living in sand regardless of chloroplast types relative to those of planktonic and tidal pool forms. Dinoflagellates seem to produce a part of their pigments in response to their habitats. PMID:26243150

  13. Pavlov and integrative physiology.

    PubMed

    Smith, G P

    2000-09-01

    Ivan Petrovich Pavlov was the first physiologist to win the Nobel Prize. The Prize was given in 1904 for his research on the neural control of salivary, gastric, and pancreatic secretion. A major reason for the success and novelty of his research was the use of unanesthetized dogs surgically prepared with chronic fistulas or gastric pouches that permitted repeated experiments in the same animal for months. Pavlov invented this chronic method because of the limitations he perceived in the use of acute anesthetized animals for investigating physiological systems. By introducing the chronic method and by showing its experimental advantages, Pavlov founded modern integrative physiology. This paper reviews Pavlov's journey from his birthplace in a provincial village in Russia to Stockholm to receive the Prize. It begins with childhood influences, describes his training and mentors, summarizes the major points of his research by reviewing his book Lectures on the Work of the Digestive Glands, and discusses his views on the relationship between physiology and medicine. PMID:10956230

  14. Proteomics as an approach to the understanding of the molecular physiology of fruit development and ripening.

    PubMed

    Palma, José M; Corpas, Francisco J; del Río, Luís A

    2011-08-12

    Fruit ripening is a developmental complex process which occurs in higher plants and involves a number of stages displayed from immature to mature fruits that depend on the plant species and the environmental conditions. Nowadays, the importance of fruit ripening comes mainly from the link between this physiological process in plants and the economic repercussions as a result of one of the human activities, the agricultural industry. In most cases, fruit ripening is accompanied by colour changes due to different pigment content and increases in sugar levels, among others. Major physiological modifications that affect colour, texture, flavour, and aroma are under the control of both external (light and temperature) and internal (developmental gene regulation and hormonal control) factors. Due to the huge amount of metabolic changes that take place during ripening in fruits from higher plants, the accomplishment of new throughput methods which can provide a global evaluation of this process would be desirable. Differential proteomics of immature and mature fruits would be a useful tool to gain information on the molecular changes which occur during ripening, but also the investigation of fruits at different ripening stages will provide a dynamic picture of the whole transformation of fruits. This subject is furthermore of great interest as many fruits are essential for human nutrition. Thus far different maturation profiles have been reported specific for each crop species. In this work, a thorough review of the proteomic database from fruit development and maturation of important crop species will be updated to understand the molecular physiology of fruits at ripening stages. PMID:21524723

  15. Physiological and Isotopic Aspects of Photosynthesis in Peperomia1

    PubMed Central

    Ting, Irwin P.; Bates, Loretta; Sternberg, Leonel O'Reilly; Deniro, Michael J.

    1985-01-01

    Physiological and isotopic aspects of several Peperomia species were investigated. All but one species had C3-like stomatal behavior, in that stomata were open during the day and closed during the night. In these species, most atmospheric CO2 uptake occurred during the day. Concurrent with this stomatal behavior, there were Crassulacean acid metabolism-like acid fluctuations in most species. Carbon and hydrogen isotope ratios of cellulose nitrate from Peperomia reflect their physiological behavior. The δ13C values of cellulose nitrate from Peperomia species were similar to values observed in C3 plants and consistent with the daytime uptake of exogeneous CO2 via the C3 photosynthetic pathway. The δD values of cellulose nitrate from Peperomia species approach those of Crassulacean acid metabolism plants. These elevated δD values are caused by fractionations occurring during biochemical reactions and not as a consequence of water relations. PMID:16664224

  16. Carotenoids, chemistry, sources and physiology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter for the Enclyclopedia of Human Nutrition (3rd edition) summarizes the structure, chemical and physiological mechanisms, dietary sources, and metabolism of carotenoids. Carotenoids are a family of phytonutrients which have antioxidant properties under most physiological conditions. Num...

  17. Polydextrose: Physiological Function, and Effects on Health.

    PubMed

    do Carmo, Mariane Moreira Ramiro; Walker, Julia Clara Leite; Novello, Daiana; Caselato, Valeria Maria; Sgarbieri, Valdemiro Carlos; Ouwehand, Arthur C; Andreollo, Nelson Adami; Hiane, Priscila Aiko; Dos Santos, Elisvânia Freitas

    2016-01-01

    Polydextrose (PDX) is a non-digestible oligosaccharide used widely across most sectors of the food industry. It is a randomly linked glucose oligomer containing small amounts of sorbitol and citric acid. The random bonds in PDX prevent mammalian digestive enzymes from readily hydrolyzing the molecule and it has a reported energy value of 1 kcal/g. These properties have led to the acceptance in many countries that PDX provides similar physiological effects as other dietary fibers and has shown prebiotic potential. Dietary intervention with prebiotics has been shown to selectively stimulate the growth and/or activity of one or a limited number of intestinal bacteria associated with several physiological benefits on health. Therefore, the objective of this review was a survey of the literature on the effect of supplementation with PDX in health, and to list the benefits for maintaining health and/or reducing the development of diseases. PMID:27618093

  18. Success stories and emerging themes in conservation physiology.

    PubMed

    Madliger, Christine L; Cooke, Steven J; Crespi, Erica J; Funk, Jennifer L; Hultine, Kevin R; Hunt, Kathleen E; Rohr, Jason R; Sinclair, Brent J; Suski, Cory D; Willis, Craig K R; Love, Oliver P

    2016-01-01

    The potential benefits of physiology for conservation are well established and include greater specificity of management techniques, determination of cause-effect relationships, increased sensitivity of health and disturbance monitoring and greater capacity for predicting future change. While descriptions of the specific avenues in which conservation and physiology can be integrated are readily available and important to the continuing expansion of the discipline of 'conservation physiology', to date there has been no assessment of how the field has specifically contributed to conservation success. However, the goal of conservation physiology is to foster conservation solutions and it is therefore important to assess whether physiological approaches contribute to downstream conservation outcomes and management decisions. Here, we present eight areas of conservation concern, ranging from chemical contamination to invasive species to ecotourism, where physiological approaches have led to beneficial changes in human behaviour, management or policy. We also discuss the shared characteristics of these successes, identifying emerging themes in the discipline. Specifically, we conclude that conservation physiology: (i) goes beyond documenting change to provide solutions; (ii) offers a diversity of physiological metrics beyond glucocorticoids (stress hormones); (iii) includes approaches that are transferable among species, locations and times; (iv) simultaneously allows for human use and benefits to wildlife; and (v) is characterized by successes that can be difficult to find in the primary literature. Overall, we submit that the field of conservation physiology has a strong foundation of achievements characterized by a diversity of conservation issues, taxa, physiological traits, ecosystem types and spatial scales. We hope that these concrete successes will encourage the continued evolution and use of physiological tools within conservation-based research and management

  19. Asthma Outcomes: Pulmonary Physiology

    PubMed Central

    Tepper, Robert S.; Wise, Robert S.; Covar, Ronina; Irvin, Charles G.; Kercsmar, Carolyn M.; Kraft, Monica; Liu, Mark C.; O’Connor, George T.; Peters, Stephen P.; Sorkness, Ronald; Togias, Alkis

    2014-01-01

    Background Outcomes of pulmonary physiology have a central place in asthma clinical research. Objective At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to provide recommendations on the use of pulmonary function measures as asthma outcomes that should be assessed in a standardized fashion in future asthma clinical trials and studies to allow for cross-study comparisons. Methods Our subcommittee conducted a comprehensive search of PubMed to identify studies that focused on the validation of various airway response tests used in asthma clinical research. The subcommittee classified the instruments as core (to be required in future studies), supplemental (to be used according to study aims and in a standardized fashion), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011. Results A list of pulmonary physiology outcomes that applies to both adults and children older than 6 years was created. These outcomes were then categorized into core, supplemental, and emerging. Spirometric outcomes (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and FEV1/FVC) are proposed as core outcomes for study population characterization, for observational studies, and for prospective clinical trials. Bronchodilator reversibility and pre- and post-bronchodilator FEV1 also are core outcomes for study population characterization and observational studies. Conclusions The subcommittee considers pulmonary physiology outcomes of central importance in asthma and proposes spirometric outcomes as core outcomes for all future NIH-initiated asthma clinical research. PMID:22386510

  20. Physiology of Iron Metabolism

    PubMed Central

    Waldvogel-Abramowski, Sophie; Waeber, Gérard; Gassner, Christoph; Buser, Andreas; Frey, Beat M.; Favrat, Bernard; Tissot, Jean-Daniel

    2014-01-01

    Summary A revolution occurred during the last decade in the comprehension of the physiology as well as in the physiopathology of iron metabolism. The purpose of this review is to summarize the recent knowledge that has accumulated, allowing a better comprehension of the mechanisms implicated in iron homeostasis. Iron metabolism is very fine tuned. The free molecule is very toxic; therefore, complex regulatory mechanisms have been developed in mammalian to insure adequate intestinal absorption, transportation, utilization, and elimination. ‘Ironomics’ certainly will be the future of the understanding of genes as well as of the protein-protein interactions involved in iron metabolism. PMID:25053935

  1. Pioneering in gravitational physiology

    NASA Technical Reports Server (NTRS)

    Soffen, G. A.

    1983-01-01

    Gravity affects biology at almost all levels above that of the cell organelle. Attention is presently given to progress made in the understanding of gravitational effects through studies employing centrifuges, clinostats, inverted preparations, linear devices, water immersion, free fall, and short- and long-term spaceflight. The cardiovascular changes which cause malaise and illness during the first few days of extended space missions are the direct result of fluid translocation from the lower extremities. Upon reentry, there is hypovolumnia and a cardiovascular deconditioning that can include tachycardia, changes in arterial blood pressure, narrow pulse pressure, and syncope. Attention is also given to NASA's gravitational physiology reseach program.

  2. The emergence of Applied Physiology within the discipline of Physiology.

    PubMed

    Tipton, Charles M

    2016-08-01

    Despite the availability and utilization of the physiology textbooks authored by Albrecht von Haller during the 18th century that heralded the modern age of physiology, not all physicians or physiologists were satisfied with its presentation, contents, or application to medicine. Initial reasons were fundamental disagreements between the "mechanists," represented by Boerhaave, Robinson, and von Haller, and the "vitalists," represented by the faculty and graduates of the Montpellier School of Medicine in France, notably, Bordeu and Barthez. Subsequently, objections originated from Europe, United Kingdom, and the United States in publications that focused not only on the teaching of physiology to medical and secondary students, but on the specific applications of the content of physiology to medicine, health, hygiene, pathology, and chronic diseases. At the turn of the 20th century, texts began to appear with applied physiology in their titles and in 1926, physician Samson Wright published a textbook entitled Applied Physiology that was intended for both medical students and the medical profession. Eleven years later, physicians Best and Taylor published The Physiological Basis of Medical Practice: A University of Toronto Texbook in Applied Physiology Although both sets of authors defined the connection between applied physiology and physiology, they failed to define the areas of physiology that were included within applied physiology. This was accomplished by the American Physiological Society (APS) Publications Committee in 1948 with the publication of the Journal of Appplied Physiology, that stated the word "applied" would broadly denote human physiology whereas the terms stress and environment would broadly include work, exercise, plus industrial, climatic and social factors. NIH established a study section (SS) devoted to applied physiology in 1964 which remained active until 2001 when it became amalgamated into other SSs. Before the end of the 20th century when

  3. A CHIPotle in physiology and disease.

    PubMed

    Paul, Indranil; Ghosh, Mrinal K

    2015-01-01

    The carboxy-terminus of Hsc70 interacting protein (CHIP) is known to function as a chaperone associated E3 ligase for several proteins and regulates a variety of physiological processes. Being a connecting link between molecular chaperones and 26S proteasomes, it is widely regarded as the central player in the cellular protein quality control system. Recent analyses have provided new insights on the biochemical and functional dynamics of CHIP. In this review article, we give a comprehensive account of our current knowledge on the biology of CHIP, which apart from shedding light on fundamental biological questions promises to provide a potential target for therapeutic intervention. PMID:25448416

  4. Physiology of bile secretion

    PubMed Central

    Esteller, Alejandro

    2008-01-01

    The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bile-duct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology. PMID:18837079

  5. Climate and taxonomy underlie different elemental concentrations and stoichiometries of forest species: the optimum “biogeochemical niche”

    PubMed Central

    Sardans, J; Peñuelas, J

    2015-01-01

    We previously hypothesised the existence of a “biogeochemical niche” occupied by each plant species. Different species should have a specific elemental composition, stoichiometry and allocation as a consequence of their particular metabolism, physiology and structure (morphology) linked to their optimal functioning under the environmental (abiotic and biotic) conditions where they have evolved. We tested this hypothesis using data from the Catalan Forestry Inventory that covers different forest groups growing under a large climatic gradient. Mediterranean species that occupy hotter-drier environments have lower leaf N, P and K concentrations than non-Mediterranean forest species. Within a determined climatic biome, different species competing in the same space have different elemental compositions and allocations linked to their taxonomical differences and their phenotypic plasticity. Gymnosperms have a proportionally higher elemental allocation to leaves than to wood, higher C concentrations, and lower N, P and K concentrations mainly in the stem and branches than angiosperms. The differences among species are linked to asymmetrical use of different elements, suggesting that the biogeochemical niche is a final expression and consequence of long-term species adaptation to particular abiotic factors, ecological role (stress tolerant, ruderal, competitor), different soil occupation and use of resources to avoid interspecific competition, and finally of a certain degree of flexibility to adapt to current environmental shifts. PMID:25983614

  6. Success stories and emerging themes in conservation physiology

    PubMed Central

    Madliger, Christine L.; Cooke, Steven J.; Crespi, Erica J.; Funk, Jennifer L.; Hultine, Kevin R.; Hunt, Kathleen E.; Rohr, Jason R.; Sinclair, Brent J.; Suski, Cory D.; Willis, Craig K. R.; Love, Oliver P.

    2016-01-01

    The potential benefits of physiology for conservation are well established and include greater specificity of management techniques, determination of cause–effect relationships, increased sensitivity of health and disturbance monitoring and greater capacity for predicting future change. While descriptions of the specific avenues in which conservation and physiology can be integrated are readily available and important to the continuing expansion of the discipline of ‘conservation physiology’, to date there has been no assessment of how the field has specifically contributed to conservation success. However, the goal of conservation physiology is to foster conservation solutions and it is therefore important to assess whether physiological approaches contribute to downstream conservation outcomes and management decisions. Here, we present eight areas of conservation concern, ranging from chemical contamination to invasive species to ecotourism, where physiological approaches have led to beneficial changes in human behaviour, management or policy. We also discuss the shared characteristics of these successes, identifying emerging themes in the discipline. Specifically, we conclude that conservation physiology: (i) goes beyond documenting change to provide solutions; (ii) offers a diversity of physiological metrics beyond glucocorticoids (stress hormones); (iii) includes approaches that are transferable among species, locations and times; (iv) simultaneously allows for human use and benefits to wildlife; and (v) is characterized by successes that can be difficult to find in the primary literature. Overall, we submit that the field of conservation physiology has a strong foundation of achievements characterized by a diversity of conservation issues, taxa, physiological traits, ecosystem types and spatial scales. We hope that these concrete successes will encourage the continued evolution and use of physiological tools within conservation-based research and

  7. Practical Application of Fundamental Concepts in Exercise Physiology

    ERIC Educational Resources Information Center

    Ramsbottom R.; Kinch, R. F. T.; Morris, M. G.; Dennis, A. M.

    2007-01-01

    The collection of primary data in laboratory classes enhances undergraduate practical and critical thinking skills. The present article describes the use of a lecture program, running in parallel with a series of linked practical classes, that emphasizes classical or standard concepts in exercise physiology. The academic and practical program ran…

  8. Knowledge Retention of Exercise Physiology Content between Athletes and Nonathletes

    ERIC Educational Resources Information Center

    Clark, Brian; Webster, Collin; Druger, Marvin

    2006-01-01

    Based on the idea that learning is linked to personal relevance, this study examined knowledge retention of exercise physiology content between college athletes and nonathletes. No differences were observed between the groups. These findings have implications on understanding the relationship between personal relevance and memory. (Contains 1…

  9. Leaf Optical Properties in Higher Plants: Linking Spectral Characteristics to Stress and Chlorophyll Concentration

    NASA Technical Reports Server (NTRS)

    Carter, Gregory A.; Knapp, Alan K.

    2000-01-01

    A number of studies have linked responses in leaf spectral reflectance, transmittance or absorptance to physiological stress. A variety of stressors including dehydration, flooding,freezing, ozone, herbicides, competition, disease, insects and deficiencies in ectomycorrhizal development and N fertilization have been imposed on species ranging from grasses to conifers and deciduous trees. In this cases, the maximum difference in reflectance within the 400 - 850 nm wavelength range between control and stressed states occurred as a reflectance increase at wavelength near 700 nm. In studies that included transmittance and absorptance as well as reflectance, maximum differences occurred as increases and decreases, respectively, near 700 nm. This common optical response to stress could be simulated closely by varying the chlorophyll concentrations in senescent leaves of five species. The optical response to stress near 700 nm, as well as corresponding changes in reflectance that occur in the green-yellow spectrum, can be explained by the general tendency of stress to reduce leaf chlorophyll concentration.

  10. [Physiological behavior of Cantilever].

    PubMed

    Feeldman, I; Frugone, R; Vládilo, N T

    1990-11-01

    The prosthetic rehabilitation is common of the integral treatment of patients that integral treatment of patients that have lost one or several dental pieces as a consequence of periodontal diseases. It has been demonstrated that plural fixed prothesis to extention, plovide a distribution pattern and magnitude of favourable forces to the periodontal during the different functions of the stomathologic apparatus, that justify rehabilitation based to it patients periodontically affected. The physiological behaviour of cantilever was basically analized on report on different investigation studies performed on patients periodontically diminis hed treated with plural fixed prothesis of crossed are with two unit or bilateral vear cantilever units, dento supported or fixed in place on implants. It is important to emphasize that favourable results previously analized in base to this type of rehabilitation in its different varieties have been obtained through record done on patients in which considerations of indications, design and occlusion stability have been optimized. PMID:2075270

  11. Single Cell Physiology

    NASA Astrophysics Data System (ADS)

    Neveu, Pierre; Sinha, Deepak Kumar; Kettunen, Petronella; Vriz, Sophie; Jullien, Ludovic; Bensimon, David

    The possibility to control at specific times and specific places the activity of biomolecules (enzymes, transcription factors, RNA, hormones, etc.) is opening up new opportunities in the study of physiological processes at the single cell level in a live organism. Most existing gene expression systems allow for tissue specific induction upon feeding the organism with exogenous inducers (e.g., tetracycline). Local genetic control has earlier been achieved by micro-injection of the relevant inducer/repressor molecule, but this is an invasive and possibly traumatic technique. In this chapter, we present the requirements for a noninvasive optical control of the activity of biomolecules and review the recent advances in this new field of research.

  12. Newborn Physiological Immaturity

    PubMed Central

    Fabrellas-Padrés, Núria; Delgado-Hito, Pilar; Hurtado-Pardos, Bárbara; Martí-Cavallé, Montserrat; Gironès-Nogué, Marta; García-Berman, Rosa-Maria; Alonso-Fernandez, Sergio

    2015-01-01

    Background: Most standardized nursing care plans for healthy neonates include multiple nursing diagnoses to reflect nurses' judgments on the infant's status; however scientific literature concerning this issue is scarce. Newborn physiological immaturity is a concept in the ATIC terminology (architecture, terminology, interface, information, nursing [infermeria], and knowledge [coneixement]) to represent the natural status of vulnerability of the healthy neonate. Purpose: To identify the essential attributes of the concept and provide its conceptual and operational definition, using the Wilsonian approach. Findings: The concept under analysis embeds a natural cluster of vulnerabilities and environmental interactions that enhance the evolving maturation process. Implications for Practice: The use of this diagnosis may simplify the process of charting the nursing care plans and reduce time needed for documentation while maintaining the integrity of the information. Implications for Research: Consistent development and use of nursing concepts is essential for knowledge building. Studies on the actual use of nursing diagnoses are needed to inform decision making. PMID:25822514

  13. Savanna Tree Seedlings are Physiologically Tolerant to Nighttime Freeze Events

    PubMed Central

    O’Keefe, Kimberly; Nippert, Jesse B.; Swemmer, Anthony M.

    2016-01-01

    Freeze events can be important disturbances in savanna ecosystems, yet the interactive effect of freezing with other environmental drivers on plant functioning is unknown. Here, we investigated physiological responses of South African tree seedlings to interactions of water availability and freezing temperatures. We grew widely distributed South African tree species (Colophospermum mopane, Combretum apiculatum, Acacia nigrescens, and Cassia abbreviata) under well-watered and water-limited conditions and exposed individuals to nighttime freeze events. Of the four species studied here, C. mopane was the most tolerant of lower water availability. However, all species were similarly tolerant to nighttime freezing and recovered within one week following the last freezing event. We also show that water limitation somewhat increased freezing tolerance in one of the species (C. mopane). Therefore, water limitation, but not freezing temperatures, may restrict the distribution of these species, although the interactions of these stressors may have species-specific impacts on plant physiology. Ultimately, we show that unique physiologies can exist among dominant species within communities and that combined stresses may play a currently unidentified role in driving the function of certain species within southern Africa. PMID:26870065

  14. Savanna Tree Seedlings are Physiologically Tolerant to Nighttime Freeze Events.

    PubMed

    O'Keefe, Kimberly; Nippert, Jesse B; Swemmer, Anthony M

    2016-01-01

    Freeze events can be important disturbances in savanna ecosystems, yet the interactive effect of freezing with other environmental drivers on plant functioning is unknown. Here, we investigated physiological responses of South African tree seedlings to interactions of water availability and freezing temperatures. We grew widely distributed South African tree species (Colophospermum mopane, Combretum apiculatum, Acacia nigrescens, and Cassia abbreviata) under well-watered and water-limited conditions and exposed individuals to nighttime freeze events. Of the four species studied here, C. mopane was the most tolerant of lower water availability. However, all species were similarly tolerant to nighttime freezing and recovered within one week following the last freezing event. We also show that water limitation somewhat increased freezing tolerance in one of the species (C. mopane). Therefore, water limitation, but not freezing temperatures, may restrict the distribution of these species, although the interactions of these stressors may have species-specific impacts on plant physiology. Ultimately, we show that unique physiologies can exist among dominant species within communities and that combined stresses may play a currently unidentified role in driving the function of certain species within southern Africa. PMID:26870065

  15. Everest Physiology Pre-2008.

    PubMed

    West, John B

    2016-01-01

    When Edmund Hillary and Tenzing Norgay reached the summit of Mt. Everest in 1953, it was the culmination of many attempts beginning in 1921. Alexander Kellas had actually predicted as early as 1920 that the mountain could be climbed, but the extreme altitude of 8848 m with the consequent oxygen deprivation had foiled previous attempts. One reason for the success of the 1953 expedition was the work done by the British physiologist Griffith Pugh in 1952 when he studied many of the physiological factors at high altitude including the oxygen requirements. Seven years later, Pugh and Hillary teamed up again for the Silver Hut Expedition in 1960-1961 that elucidated many of the problems of very high altitude. A group of physiologists spent several months at an altitude of 5800 m in a prefabricated hut and studied many aspects of exercise, pulmonary gas exchange, control of ventilation, and blood changes. Maximal exercise was measured as high as 7440 m and raised anew the question of whether Everest could ever be climbed without supplementary oxygen. The answer was shown to be yes in 1978 by Messner and Habeler, and 3 years later the American Medical Research Expedition to Everest clarified the physiological adaptations that allow humans to reach the highest point on earth. Five people reached the summit, the barometric pressure there was measured for the first time, and alveolar gas samples from the summit showed the critical importance of the extreme hyperventilation. However, the maximal oxygen consumption for the summit inspired PO2 of 43 mmHg was shown to be only about 1 l min(-1). In other words, the highest point on earth is very close to the limit of human tolerance to oxygen deprivation. As we celebrate the anniversary of Charles Darwin, it would be nice to have an evolutionary explanation for this, but in fact it is a cosmic coincidence. PMID:27343114

  16. [The physiology of erection].

    PubMed

    Hora, M; Vozeh, F

    1997-06-12

    The majority of contemporary knowledge on the physiology of erection was assembled during the past thirty years. Today we consider erection as a multifactorial process. Mechanically it can be compared to an electromechanically controlled hydraulic system. Its function is conditioned by a number of mutually coordinated processes. As to nervous processes they include autonomous (parasympathetic and sympathetic) innervation, as well as somatic innervation (sensory and motor pathways). The control function is exerted by spinal as well as cerebral centres. As to mediators, in particular acetylcholine, nitrous oxide (NO) released from the endothelium are involved, noradrenaline, VIP (vasoactive intestinal polypeptide), CGRP (calcitonin gene-related peptide) and prostaglandins. The most important roles in the phase of erection are played by nitrous oxide and VIP. Erection can be either reflex erection, psychogenic or nocturnal or morning. It usually takes place in six stages (at rest, latent, the tumescence stage, complete erection, rigid erection and subsequently the stage of detumescence). Except for neurohumoral mechanisms an essential prerequisite for the development of erection are the arterial supply of the genital and the so-called venoocclusive mechanism. Erection takes the following course (simplified): erotogenic stimuli lead to the stimulation of the parasympathetic nerve-->vasodilating substances are released-->the s inusoids are filled with blood (tumescence stage)-->the venoocclusive mechanism starts to work: thus complete erection occurs. Then the contractions of the musculature of the perineum compress the proximal portions of the corpora cavernosa: this leads to rigid erection. Detumescence which occurs as a rule after ejaculation) is due to released noradrenaline (active stage) and the reduced tonus of the smooth muscles of the blood vessels (released endothelin and neuropeptide Y). Knowledge of the physiological mechanisms of erection made clinical

  17. Morphological and Physiological Compensation Promote Climate-Induced Invasions Above and below Treeline

    NASA Astrophysics Data System (ADS)

    Winkler, D. E.; Huxman, T. E.; Kudo, G.

    2014-12-01

    Elucidating the mechanisms underlying invasive species success is a challenge in ecology. Treeline ecotones are eminently suited to address this challenge given their sensitivity to climate change and the different abiotic filters in place over short distances. The invasive dwarf bamboo Sasa kurilensis has had pronounced effects on Japanese alpine plant communities, including the loss of over 1/3 of native species in some areas. The drivers of S. kurilensis invasions remain unresolved. We evaluated S. kurilensis stands along elevation and moisture gradients in Daisetsuzan National Park (Hokkaido, Japan) to identify strategy shifts that might facilitate invasions. We anticipated morphological responses to be correlated with invasion above treeline, while physiological processes to be more coordinated below treeline, reflecting different ecological filters in place within each community. We compared growth patterns and plant water status in the native (i.e., montane forests) and invasive (i.e., subalpine and alpine meadows) ranges of S. kurilensis. Dwarf bamboo at native lower elevations were taller than those at newly-invaded upper limits, indicating light limitation and investment in culm elongation. Culms in the native range grew faster than those at higher elevations. In contrast, culm density increased and plants allocated more to photosynthetic structures in invaded areas without overstory. Plants tended to invade drier soils but showed increased water stress, likely compensating by producing more photosynthetic structures to promote carbon gain. Overall, our results reveal dwarf bamboo exhibits both morphological and physiological variation across treeline ecotones. This appears to enable it to successfully invade subalpine and alpine communities while responding to a new climate. This pattern of variation coupled with changing soil dynamics as a result of earlier snowmelt will likely continue to promote the invasion of S. kurilensis into these systems

  18. Olfactory morphology and physiology of elasmobranchs.

    PubMed

    Meredith, Tricia L; Kajiura, Stephen M

    2010-10-15

    Elasmobranch fishes are thought to possess greater olfactory sensitivities than teleost fishes due in part to the large amount of epithelial surface area that comprises their olfactory organs; however, direct evidence correlating the size of the olfactory organ to olfactory sensitivity is lacking. This study examined the olfactory morphology and physiology of five distantly related elasmobranch species. Specifically, we quantified the number of lamellae and lamellar surface area (as if it were a flat sheet, not considering secondary lamellae) that comprise their olfactory organs. We also calculated the olfactory thresholds and relative effectiveness of amino acid odorants for each species. The olfactory organs varied in both the number of lamellae and lamellar surface area, which may be related to their general habitat, but neither correlated with olfactory threshold. Thresholds to amino acid odorants, major olfactory stimuli of all fishes, ranged from 10⁻⁹·⁰ to 10⁻⁶·⁹ mol l⁻¹, which indicates that these elasmobranch species demonstrate comparable thresholds with teleosts. In addition, the relative effectiveness of amino acid stimuli to the olfactory organ of elasmobranchs is similar to that previously described in teleosts with neutral amino acids eliciting significantly greater responses than others. Collectively, these results indicate parallels in olfactory physiology between these two groups of fishes. PMID:20889825

  19. Anticipatory physiological regulation in feeding biology

    PubMed Central

    Power, Michael L.; Schulkin, Jay

    2008-01-01

    Anticipatory physiological regulation is an adaptive strategy that enables animals to respond faster to physiologic and metabolic challenges. The cephalic phase responses are anticipatory responses that prepare animals to digest, absorb and metabolize nutrients. They enable the sensory aspects of the food to interact with the metabolic state of the animal to influence feeding behavior. The anticipatory digestive secretions and metabolic adjustments in response to food cues are key adaptations that affect digestive and metabolic efficiency and aid in controlling the resulting elevation of metabolic fuels in the blood. Cephalic phase responses enable digestion, metabolism and appetite to be regulated in a coordinated fashion. These responses have significant effects on meal size. For example, if the cephalic phase insulin response is blocked the result is poor glucose control and smaller meals. Cephalic phase responses also are linked to motivation to feed, and may play a more direct role in regulating meal size beyond the permissive one of ameliorating negative consequences of feeding. For example, the orexigenic peptide ghrelin appears to display a cephalic phase response, rising before expected meal times. This anticipatory ghrelin response increases appetite; interestingly it also enhances fat absorption, linking appetite with digestion and metabolism. PMID:18045735

  20. Procedures of Exercise Physiology Laboratories

    NASA Technical Reports Server (NTRS)

    Bishop, Phillip A.; Fortney, Suzanne; Greenisen, Michael; Siconolfi, Steven F.; Bamman, Marcas M.; Moore, Alan D., Jr.; Squires, William

    1998-01-01

    This manual describes the laboratory methods used to collect flight crew physiological performance data at the Johnson Space Center. The Exercise Countermeasures Project Laboratory is a standard physiology laboratory; only the application to the study of human physiological adaptations to spaceflight is unique. In the absence of any other recently published laboratory manual, this manual should be a useful document staffs and students of other laboratories.

  1. PHYSIOLOGICAL IMPACT OF DREDGED SEDIMENT ON TWO BENTHIC SPECIES

    EPA Science Inventory

    Several international commissions have recently called for effective short-term biological response measurements which can adequately detect the effects of environmental concentrations of contaminants. The report describes efforts to develop a direct comparison of the effects of ...

  2. Milkweed butterfly resistance to plant toxins is linked to sequestration, not coping with a toxic diet.

    PubMed

    Petschenka, Georg; Agrawal, Anurag A

    2015-11-01

    Insect resistance to plant toxins is widely assumed to have evolved in response to using defended plants as a dietary resource. We tested this hypothesis in the milkweed butterflies (Danaini) which have progressively evolved higher levels of resistance to cardenolide toxins based on amino acid substitutions of their cellular sodium-potassium pump (Na(+)/K(+)-ATPase). Using chemical, physiological and caterpillar growth assays on diverse milkweeds (Asclepias spp.) and isolated cardenolides, we show that resistant Na(+)/K(+)-ATPases are not necessary to cope with dietary cardenolides. By contrast, sequestration of cardenolides in the body (as a defence against predators) is associated with the three levels of Na(+)/K(+)-ATPase resistance. To estimate the potential physiological burden of cardenolide sequestration without Na(+)/K(+)-ATPase adaptations, we applied haemolymph of sequestering species on isolated Na(+)/K(+)-ATPase of sequestering and non-sequestering species. Haemolymph cardenolides dramatically impair non-adapted Na(+)/K(+)-ATPase, but had systematically reduced effects on Na(+)/K(+)-ATPase of sequestering species. Our data indicate that major adaptations to plant toxins may be evolutionarily linked to sequestration, and may not necessarily be a means to eat toxic plants. Na(+)/K(+)-ATPase adaptations thus were a potential mechanism through which predators spurred the coevolutionary arms race between plants and insects. PMID:26538594

  3. Invasive Acer negundo outperforms native species in non-limiting resource environments due to its higher phenotypic plasticity

    PubMed Central

    2011-01-01

    Background To identify the determinants of invasiveness, comparisons of traits of invasive and native species are commonly performed. Invasiveness is generally linked to higher values of reproductive, physiological and growth-related traits of the invasives relative to the natives in the introduced range. Phenotypic plasticity of these traits has also been cited to increase the success of invasive species but has been little studied in invasive tree species. In a greenhouse experiment, we compared ecophysiological traits between an invasive species to Europe, Acer negundo, and early- and late-successional co-occurring native species, under different light, nutrient availability and disturbance regimes. We also compared species of the same species groups in situ, in riparian forests. Results Under non-limiting resources, A. negundo seedlings showed higher growth rates than the native species. However, A. negundo displayed equivalent or lower photosynthetic capacities and nitrogen content per unit leaf area compared to the native species; these findings were observed both on the seedlings in the greenhouse experiment and on adult trees in situ. These physiological traits were mostly conservative along the different light, nutrient and disturbance environments. Overall, under non-limiting light and nutrient conditions, specific leaf area and total leaf area of A. negundo were substantially larger. The invasive species presented a higher plasticity in allocation to foliage and therefore in growth with increasing nutrient and light availability relative to the native species. Conclusions The higher level of plasticity of the invasive species in foliage allocation in response to light and nutrient availability induced a better growth in non-limiting resource environments. These results give us more elements on the invasiveness of A. negundo and suggest that such behaviour could explain the ability of A. negundo to outperform native tree species, contributes to its spread

  4. Physiology of vitreous surgery.

    PubMed

    Stefánsson, Einar

    2009-02-01

    Vitreous surgery has various physiological and clinical consequences, both beneficial and harmful. Vitrectomy reduces the risk of retinal neovascularization, while increasing the risk of iris neovascularization, reduces macular edema and stimulates cataract formation. These clinical consequences may be understood with the help of classical laws of physics and physiology. The laws of Fick, Stokes-Einstein and Hagen-Poiseuille state that molecular transport by diffusion or convection is inversely related to the viscosity of the medium. When the vitreous gel is replaced with less viscous saline, the transport of all molecules, including oxygen and cytokines, is facilitated. Oxygen transport to ischemic retinal areas is improved, as is clearance of VEGF and other cytokines from these areas, thus reducing edema and neovascularization. At the same time, oxygen is transported faster down a concentration gradient from the anterior to the posterior segment, while VEGF moves in the opposite direction, making the anterior segment less oxygenated and with more VEGF, stimulating iris neovascularization. Silicone oil is the exception that proves the rule: it is more viscous than vitreous humour, re-establishes the transport barrier to oxygen and VEGF, and reduces the risk for iris neovascularization in the vitrectomized-lentectomized eye. Modern vitreous surgery involves a variety of treatment options in addition to vitrectomy itself, such as photocoagulation, anti-VEGF drugs, intravitreal steroids and release of vitreoretinal traction. A full understanding of these treatment modalities allows sensible combination of treatment options. Retinal photocoagulation has repeatedly been shown to improve retinal oxygenation, as does vitrectomy. Oxygen naturally reduces VEGF production and improves retinal hemodynamics. The VEGF-lowering effect of photocoagulation and vitrectomy can be augmented with anti-VEGF drugs and the permeability effect of VEGF reduced with corticosteroids

  5. Comparison of physiological responses to affect eliciting pictures and music.

    PubMed

    Kim, Jongwan; Wedell, Douglas H

    2016-03-01

    Recent investigations of the neural correlates of affect elicited from different modalities have found both modality-general and modality-specific representations (Chikazoe et al., 2014). The implications for how physiological responses to affect differ across stimulus modalities have not been fully investigated. This study examined similarities and differences between physiological signatures of affect derived from two different modes of presentation: visual pictures and auditory music sampled from an affective space defined by valence and arousal. Electromyography recordings for the zygomaticus major (EMGZ) and corrugator supercilii (EMGC) were measured along with heart rate and skin conductance level (SCL). Multidimensional scaling was used to visualize relationships from physiological and behavioral responses, and the observed relationships were statistically evaluated using multivariate and univariate analyses. Results for physiological measures demonstrated that valence was represented in the same general way across modalities, primarily reflected in EMGC responses. Arousal, however, was represented in a modality-specific manner, with SCL and EMGZ sensitive to music-based arousal but not picture-based arousal. Stimulus modality itself was predicted from EMGC. Thus, physiological responses to valence were similar across modalities but physiological responses to arousal differed across modalities. These results support the utility of testing for affective markers across modalities within the same experimental setting to reveal how physiological responses are linked to either affect, stimulus modality or both. PMID:26752207

  6. The Physiology Teacher: Abstracts of Educational Materials in Physiology

    ERIC Educational Resources Information Center

    Physiologist, 1978

    1978-01-01

    Presents the third annual collection of abstracts of educational materials presented by the Educational Materials Review Board of the American Physiological Society. Board members have submitted abstracts of review articles, papers, textbooks, books, manuals, handbooks and symposia which they have found valuable in teaching physiology. (Author/CP)

  7. An integrated physiology model to study regional lung damage effects and the physiologic response

    PubMed Central

    2014-01-01

    Background This work expands upon a previously developed exercise dynamic physiology model (DPM) with the addition of an anatomic pulmonary system in order to quantify the impact of lung damage on oxygen transport and physical performance decrement. Methods A pulmonary model is derived with an anatomic structure based on morphometric measurements, accounting for heterogeneous ventilation and perfusion observed experimentally. The model is incorporated into an existing exercise physiology model; the combined system is validated using human exercise data. Pulmonary damage from blast, blunt trauma, and chemical injury is quantified in the model based on lung fluid infiltration (edema) which reduces oxygen delivery to the blood. The pulmonary damage component is derived and calibrated based on published animal experiments; scaling laws are used to predict the human response to lung injury in terms of physical performance decrement. Results The augmented dynamic physiology model (DPM) accurately predicted the human response to hypoxia, altitude, and exercise observed experimentally. The pulmonary damage parameters (shunt and diffusing capacity reduction) were fit to experimental animal data obtained in blast, blunt trauma, and chemical damage studies which link lung damage to lung weight change; the model is able to predict the reduced oxygen delivery in damage conditions. The model accurately estimates physical performance reduction with pulmonary damage. Conclusions We have developed a physiologically-based mathematical model to predict performance decrement endpoints in the presence of thoracic damage; simulations can be extended to estimate human performance and escape in extreme situations. PMID:25044032

  8. Starting physiology: bioelectrogenesis.

    PubMed

    Baptista, Vander

    2015-12-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The topic of bioelectrogenesis encompasses multidisciplinary concepts, involves several mechanisms, and is a dynamic process, i.e., it never turns off during the lifetime of the cell. Therefore, to improve the transmission and acquisition of knowledge in this field, I present an alternative didactic model. The design of the model assumes that it is possible to build, in a series of sequential steps, an assembly of proteins within the membrane of an isolated cell in a simulated electrophysiology experiment. Initially, no proteins are inserted in the membrane and the cell is at a baseline energy state; the extracellular and intracellular fluids are at thermodynamic equilibrium. Students are guided through a sequence of four steps that add key membrane transport proteins to the model cell. The model is simple at the start and becomes progressively more complex, finally producing transmembrane chemical and electrical gradients. I believe that this didactic approach helps instructors with a more efficient tool for the teaching of the mechanisms of resting membrane potential while helping students avoid common difficulties that may be encountered when learning this topic. PMID:26628666

  9. Polyamines in plant physiology

    NASA Technical Reports Server (NTRS)

    Galston, A. W.; Sawhney, R. K.

    1990-01-01

    The diamine putrescine, the triamine spermidine, and the tetramine spermine are ubiquitous in plant cells, while other polyamines are of more limited occurrence. Their chemistry and pathways of biosynthesis and metabolism are well characterized. They occur in the free form as cations, but are often conjugated to small molecules like phenolic acids and also to various macromolecules. Their titer varies from approximately micromolar to more than millimolar, and depends greatly on environmental conditions, especially stress. In cereals, the activity of one of the major polyamine biosynthetic enzymes, arginine decarboxylase, is rapidly and dramatically increased by almost every studied external stress, leading to 50-fold or greater increases in putrescine titer within a few hours. The physiological significance of this increase is not yet clear, although most recent work suggests an adaptive, protective role. Polyamines produced through the action of ornithine decarboxylase, by contrast, seem essential for DNA replication and cell division. The application of exogenous polyamines produces effects on patterns of senescence and morphogenesis, suggesting but not proving a regulatory role for polyamines in these processes. The evidence for such a regulatory role is growing.

  10. Physiology of circadian entrainment.

    PubMed

    Golombek, Diego A; Rosenstein, Ruth E

    2010-07-01

    Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period of this oscillation is of approximately 24 h, to keep synchrony with the environment, circadian rhythms need to be entrained daily by means of Zeitgeber ("time giver") signals, such as the light-dark cycle. Recent advances in the neurophysiology and molecular biology of circadian rhythmicity allow a better understanding of synchronization. In this review we cover several aspects of the mechanisms for photic entrainment of mammalian circadian rhythms, including retinal sensitivity to light by means of novel photopigments as well as circadian variations in the retina that contribute to the regulation of retinal physiology. Downstream from the retina, we examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction with SCN receptors and the resulting signal transduction pathways in suprachiasmatic neurons, as well as putative neuron-glia interactions. Finally, we describe and analyze clock gene expression and its importance in entrainment mechanisms, as well as circadian disorders or retinal diseases related to entrainment deficits, including experimental and clinical treatments. PMID:20664079

  11. Nonindigenous vs. native species: A comparison of preferred niche breadth

    EPA Science Inventory

    To successfully invade and expand their populations, nonindigenous species must be able to physiologically cope with their new environment. Given this, species that tolerate a wide array of environmental conditions are often predicted to be better at establishing populations in ...

  12. PHYSIOLOGICALLY-BASED PHARMACOKINETIC MODELING

    EPA Science Inventory

    Physiologically-based pharmacokinetic (PB-PK) models attempt to provide both a realistic anatomic description of the animal to which a drug or toxic chemical has been administered and a biologically accurate representation of the physiological pathways for chemical storage, metab...

  13. Non-invasive physiological measurements

    SciTech Connect

    Rolfe, P.

    1983-01-01

    This book discusses the diagnostic techniques of nondestructive type for monitoring the physiology of various organ systems. The topics covered are: non-invasive assessment of gastric activity; uterine activity, intestinal activity; monitoring of fetal cardiovascular system and bilirubin physiology of infants. Respiratory system of infants is monitored and ultrasonography of heart is discussed.

  14. Physiological Considerations of Artificial Gravity

    NASA Technical Reports Server (NTRS)

    Cramer, D. B.

    1985-01-01

    Weightlessness produces significant physiological changes. Whether these changes will stabilize or achieve medical significance is not clear. Artificial gravity is the physiological countermeasure, and the tether system represents an attractive approach to artificial gravity. The need for artificial gravity is examined.

  15. Comparative Digestive Physiology

    PubMed Central

    Karasov, William H.; Douglas, Angela E.

    2015-01-01

    In vertebrates and invertebrates, morphological and functional features of gastrointestinal (GI) tracts generally reflect food chemistry, such as content of carbohydrates, proteins, fats, and material(s) refractory to rapid digestion (e.g., cellulose). The expression of digestive enzymes and nutrient transporters approximately matches the dietary load of their respective substrates, with relatively modest excess capacity. Mechanisms explaining differences in hydrolase activity between populations and species include gene copy number variations and single-nucleotide polymorphisms. Transcriptional and posttranscriptional adjustments mediate phenotypic changes in the expression of hydrolases and transporters in response to dietary signals. Many species respond to higher food intake by flexibly increasing digestive compartment size. Fermentative processes by symbiotic microorganisms are important for cellulose degradation but are relatively slow, so animals that rely on those processes typically possess special enlarged compartment(s) to maintain a microbiota and other GI structures that slow digesta flow. The taxon richness of the gut microbiota, usually identified by 16S rRNA gene sequencing, is typically an order of magnitude greater in vertebrates than invertebrates, and the interspecific variation in microbial composition is strongly influenced by diet. Many of the nutrient transporters are orthologous across different animal phyla, though functional details may vary (e.g., glucose and amino acid transport with K+ rather than Na+ as a counter ion). Paracellular absorption is important in many birds. Natural toxins are ubiquitous in foods and may influence key features such as digesta transit, enzymatic breakdown, microbial fermentation, and absorption PMID:23720328

  16. Linking transcriptional responses to organismal tolerance reveals mechanisms of thermal sensitivity in a mesothermal endangered fish.

    PubMed

    Komoroske, Lisa M; Connon, Richard E; Jeffries, Ken M; Fangue, Nann A

    2015-10-01

    Forecasting species' responses to climate change requires understanding the underlying mechanisms governing environmental stress tolerance, including acclimation capacity and acute stress responses. Current knowledge of these physiological processes in aquatic ectotherms is largely drawn from eurythermal or extreme stenothermal species. Yet many species of conservation concern exhibit tolerance windows and acclimation capacities in between these extremes. We linked transcriptome profiles to organismal tolerance in a mesothermal endangered fish, the delta smelt (Hypomesus transpacificus), to quantify the cellular processes, sublethal thresholds and effects of thermal acclimation on acute stress responses. Delta smelt initiated rapid molecular changes in line with expectations of theoretical thermal limitation models, but also exhibited diminished capacity to modify the expression of some genes and cellular mechanisms key to coping with acute thermal stress found in eurytherms. Sublethal critical thresholds occurred 4-6 °C below their upper tolerance limits, and thermal acclimation shifted the onset of acute thermal stress and tolerance as predicted. However, we found evidence that delta smelt's limited thermal plasticity may be partially due to an inability of individuals to effectively make physiological adjustments to truly achieve new homoeostasis under heightened temperatures, resulting in chronic thermal stress. These findings provide insight into the physiological basis of the diverse patterns of thermal tolerances observed in nature. Moreover, understanding how underlying molecular mechanisms shape thermal acclimation capacity, acute stress responses and ultimately differential phenotypes contributes to a predictive framework to deduce species' responses in situ to changes in selective pressures due to climate change. PMID:26339983

  17. Causality in physiological signals.

    PubMed

    Müller, Andreas; Kraemer, Jan F; Penzel, Thomas; Bonnemeier, Hendrik; Kurths, Jürgen; Wessel, Niels

    2016-05-01

    Health is one of the most important non-material assets and thus also has an enormous influence on material values, since treating and preventing diseases is expensive. The number one cause of death worldwide today originates in cardiovascular diseases. For these reasons the aim of understanding the functions and the interactions of the cardiovascular system is and has been a major research topic throughout various disciplines for more than a hundred years. The purpose of most of today's research is to get as much information as possible with the lowest possible effort and the least discomfort for the subject or patient, e.g. via non-invasive measurements. A family of tools whose importance has been growing during the last years is known under the headline of coupling measures. The rationale for this kind of analysis is to identify the structure of interactions in a system of multiple components. Important information lies for example in the coupling direction, the coupling strength, and occurring time lags. In this work, we will, after a brief general introduction covering the development of cardiovascular time series analysis, introduce, explain and review some of the most important coupling measures and classify them according to their origin and capabilities in the light of physiological analyses. We will begin with classical correlation measures, go via Granger-causality-based tools, entropy-based techniques (e.g. momentary information transfer), nonlinear prediction measures (e.g. mutual prediction) to symbolic dynamics (e.g. symbolic coupling traces). All these methods have contributed important insights into physiological interactions like cardiorespiratory coupling, neuro-cardio-coupling and many more. Furthermore, we will cover tools to detect and analyze synchronization and coordination (e.g. synchrogram and coordigram). As a last point we will address time dependent couplings as identified using a recent approach employing ensembles of time series. The

  18. Applied physiology of cycling.

    PubMed

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  19. Physiology of temperature regulation: comparative aspects.

    PubMed

    Bicego, Kênia C; Barros, Renata C H; Branco, Luiz G S

    2007-07-01

    Few environmental factors have a larger influence on animal energetics than temperature, a fact that makes thermoregulation a very important process for survival. In general, endothermic species, i.e., mammals and birds, maintain a constant body temperature (Tb) in fluctuating environmental temperatures using autonomic and behavioural mechanisms. Most of the knowledge on thermoregulatory physiology has emerged from studies using mammalian species, particularly rats. However, studies with all vertebrate groups are essential for a more complete understanding of the mechanisms involved in the regulation of Tb. Ectothermic vertebrates-fish, amphibians and reptiles-thermoregulate essentially by behavioural mechanisms. With few exceptions, both endotherms and ectotherms develop fever (a regulated increase in Tb) in response to exogenous pyrogens, and regulated hypothermia (anapyrexia) in response to hypoxia. This review focuses on the mechanisms, particularly neuromediators and regions in the central nervous system, involved in thermoregulation in vertebrates, in conditions of euthermia, fever and anapyrexia. PMID:16950637

  20. Physiological correlates of mental workload

    NASA Technical Reports Server (NTRS)

    Zacharias, G. L.

    1980-01-01

    A literature review was conducted to assess the basis of and techniques for physiological assessment of mental workload. The study findings reviewed had shortcomings involving one or more of the following basic problems: (1) physiologic arousal can be easily driven by nonworkload factors, confounding any proposed metric; (2) the profound absence of underlying physiologic models has promulgated a multiplicity of seemingly arbitrary signal processing techniques; (3) the unspecified multidimensional nature of physiological "state" has given rise to a broad spectrum of competing noncommensurate metrics; and (4) the lack of an adequate definition of workload compels physiologic correlations to suffer either from the vagueness of implicit workload measures or from the variance of explicit subjective assessments. Using specific studies as examples, two basic signal processing/data reduction techniques in current use, time and ensemble averaging are discussed.

  1. Bordetella bronchiseptica responses to physiological reactive nitrogen and oxygen stresses

    PubMed Central

    Omsland, Anders; Miranda, Katrina M.; Friedman, Richard L.; Boitano, Scott

    2008-01-01

    Bordetella bronchiseptica can establish prolonged airway infection consistent with a highly developed ability to evade mammalian host immune responses. Upon initial interaction with the host upper respiratory tract mucosa, B. bronchiseptica are subjected to antimicrobial reactive nitrogen species (RNS) and reactive oxygen species (ROS), effector molecules of the innate immune system. However, the responses of B. bronchiseptica to redox species at physiologically relevant concentrations (nM-µM) have not been investigated. Using predicted physiological concentrations of nitric oxide (NO), superoxide (O2.−) and hydrogen peroxide (H2O2) on low numbers of colony forming units (CFU) of B. bronchiseptica, all redox active species displayed dose-dependent antimicrobial activity. Susceptibility to individual redox active species was significantly increased upon introduction of a second species at sub-antimicrobial concentrations. An increased bacteriostatic activity of NO was observed relative to H2O2. The understanding of Bordetella responses to physiologically relevant levels of exogenous RNS and ROS will aid in defining the role of endogenous production of these molecules in host innate immunity against Bordetella and other respiratory pathogens. PMID:18462394

  2. Physiologically based quantitative modeling of unihemispheric sleep.

    PubMed

    Kedziora, D J; Abeysuriya, R G; Phillips, A J K; Robinson, P A

    2012-12-01

    Unihemispheric sleep has been observed in numerous species, including birds and aquatic mammals. While knowledge of its functional role has been improved in recent years, the physiological mechanisms that generate this behavior remain poorly understood. Here, unihemispheric sleep is simulated using a physiologically based quantitative model of the mammalian ascending arousal system. The model includes mutual inhibition between wake-promoting monoaminergic nuclei (MA) and sleep-promoting ventrolateral preoptic nuclei (VLPO), driven by circadian and homeostatic drives as well as cholinergic and orexinergic input to MA. The model is extended here to incorporate two distinct hemispheres and their interconnections. It is postulated that inhibitory connections between VLPO nuclei in opposite hemispheres are responsible for unihemispheric sleep, and it is shown that contralateral inhibitory connections promote unihemispheric sleep while ipsilateral inhibitory connections promote bihemispheric sleep. The frequency of alternating unihemispheric sleep bouts is chiefly determined by sleep homeostasis and its corresponding time constant. It is shown that the model reproduces dolphin sleep, and that the sleep regimes of humans, cetaceans, and fur seals, the latter both terrestrially and in a marine environment, require only modest changes in contralateral connection strength and homeostatic time constant. It is further demonstrated that fur seals can potentially switch between their terrestrial bihemispheric and aquatic unihemispheric sleep patterns by varying just the contralateral connection strength. These results provide experimentally testable predictions regarding the differences between species that sleep bihemispherically and unihemispherically. PMID:22960411

  3. The conservation physiology of seed dispersal

    PubMed Central

    Ruxton, Graeme D.; Schaefer, H. Martin

    2012-01-01

    At a time when plant species are experiencing increasing challenges from climate change, land-use change, harvesting and invasive species, dispersal has become a very important aspect of plant conservation. Seed dispersal by animals is particularly important because some animals disperse seeds to suitable sites in a directed fashion. Our review has two aims: (i) to highlight the various ways plant dispersal by animals can be affected by current anthropogenic change and (ii) to show the important role of plant and (particularly) animal physiology in shaping seed–dispersal interactions. We argue that large-bodied seed dispersers may be particularly important for plant conservation because seed dispersal of large-seeded plants is often more specialized and because large-bodied animals are targeted by human exploitation and have smaller population sizes. We further argue that more specialized seed-dispersal systems on island ecosystems might be particularly at risk from climate change both owing to small population sizes involved but also owing to the likely thermal specialization, particularly on tropical islands. More generally, the inherent vulnerability of seed-dispersal mutualisms to disruption driven by environmental change (as well as their ubiquity) demands that we continue to improve our understanding of their conservation physiology. PMID:22566677

  4. Impact of simulated heat waves on soybean physiology and yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With increases in mean global temperatures and associated climate change, extreme temperature events are predicted to increase in both intensity and frequency. Despite the clearly documented negative public health impacts of heat waves, the impact on physiology and yields of key agricultural species...

  5. Physiological Effects of Trace Elements and Chemicals in Water

    ERIC Educational Resources Information Center

    Varma, M. M.; And Others

    1976-01-01

    The physiological effects on humans and animals of trace amounts of organic and unorganic pollutants in natural and waste waters are examined. The sensitivity of particular organs and species is emphasized. Substances reviewed include mercury, arsenic, cadmium, lead, chromium, fluorides, nitrates and organics, including polychlounated biphenyls.…

  6. PHYSIOLOGICAL EFFECTS OF DRILLING MUDS ON REEF CORALS

    EPA Science Inventory

    Pieces of coral from two species, Montastrea annularis and Acropora cervicornis, were exposed in the laboratory to concentrations of 0, 1, 10, and 100 ppm drilling mud for periods of two days to seven weeks. Several physiological functions of the coral animal (calcification rate,...

  7. Physiological ecology in the 21st century: advancements in biologging science.

    PubMed

    Block, Barbara A

    2005-04-01

    Top pelagic predators such as tunas, sharks, marine turtles and mammals have historically been difficult to study due to their large body size and vast range over the oceanic habitat. In recent years the development of small microprocessor-based data storage tags that are surgically implanted or satellite-linked provide marine researchers a novel avenue for examining the movements, physiology and behaviors of pelagic animals in the wild. When biological and physical data obtained from the tags are combined with satellite derived sea surface temperature and ocean color data, the relationships between the movements, behaviors and physical ocean environment can be examined. Tag-bearing marine animals can function as autonomous ocean profilers providing oceanographic data wherever their long migrations take them. The biologging science is providing ecological physiologists with new insights into the seasonal movements, habitat utilization, breeding behaviors and population structures in of marine vertebrates. In addition, the data are revealing migration corridors, hot spots and physical oceanographic patterns that are key to understanding how organisms such as bluefin tunas use the open ocean environment. In the 21st century as ecosystem degradation and global warming continue to threaten the existence of species on Earth, the field of physiological ecology will play a more pivotal role in conservation biology. PMID:21676774

  8. Bears Show a Physiological but Limited Behavioral Response to Unmanned Aerial Vehicles.

    PubMed

    Ditmer, Mark A; Vincent, John B; Werden, Leland K; Tanner, Jessie C; Laske, Timothy G; Iaizzo, Paul A; Garshelis, David L; Fieberg, John R

    2015-08-31

    Unmanned aerial vehicles (UAVs) have the potential to revolutionize the way research is conducted in many scientific fields. UAVs can access remote or difficult terrain, collect large amounts of data for lower cost than traditional aerial methods, and facilitate observations of species that are wary of human presence. Currently, despite large regulatory hurdles, UAVs are being deployed by researchers and conservationists to monitor threats to biodiversity, collect frequent aerial imagery, estimate population abundance, and deter poaching. Studies have examined the behavioral responses of wildlife to aircraft (including UAVs), but with the widespread increase in UAV flights, it is critical to understand whether UAVs act as stressors to wildlife and to quantify that impact. Biologger technology allows for the remote monitoring of stress responses in free-roaming individuals, and when linked to locational information, it can be used to determine events or components of an animal's environment that elicit a physiological response not apparent based on behavior alone. We assessed effects of UAV flights on movements and heart rate responses of free-roaming American black bears. We observed consistently strong physiological responses but infrequent behavioral changes. All bears, including an individual denned for hibernation, responded to UAV flights with elevated heart rates, rising as much as 123 beats per minute above the pre-flight baseline. It is important to consider the additional stress on wildlife from UAV flights when developing regulations and best scientific practices. PMID:26279232

  9. Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.

    PubMed

    Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal

    2016-01-01

    Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed. PMID:26138759

  10. Genetic and physiological bases for phenological responses to current and predicted climates

    PubMed Central

    Wilczek, A. M.; Burghardt, L. T.; Cobb, A. R.; Cooper, M. D.; Welch, S. M.; Schmitt, J.

    2010-01-01

    We are now reaching the stage at which specific genetic factors with known physiological effects can be tied directly and quantitatively to variation in phenology. With such a mechanistic understanding, scientists can better predict phenological responses to novel seasonal climates. Using the widespread model species Arabidopsis thaliana, we explore how variation in different genetic pathways can be linked to phenology and life-history variation across geographical regions and seasons. We show that the expression of phenological traits including flowering depends critically on the growth season, and we outline an integrated life-history approach to phenology in which the timing of later life-history events can be contingent on the environmental cues regulating earlier life stages. As flowering time in many plants is determined by the integration of multiple environmentally sensitive gene pathways, the novel combinations of important seasonal cues in projected future climates will alter how phenology responds to variation in the flowering time gene network with important consequences for plant life history. We discuss how phenology models in other systems—both natural and agricultural—could employ a similar framework to explore the potential contribution of genetic variation to the physiological integration of cues determining phenology. PMID:20819808

  11. Linking | Smokefree.gov

    Cancer.gov

    Links to individual pages within the Smokefree.gov Web site are permissible, provided attribution is made to Smokefree.gov and any descriptive notes accurately reflect the content of the linked page(s).

  12. The link between immunity and life history traits in scleractinian corals

    PubMed Central

    Dornberger, Lindsey; Beach-Letendre, Joshuah; Weil, Ernesto; Mydlarz, Laura D.

    2014-01-01

    -growing massive species. In corals, energetic investments in life-history traits such as reproduction and growth rate (higher energy investment) seem to have a significant impact on their capacity to respond to stressors, including infectious diseases and coral bleaching. These differences in energy investment are critical in the light of the recent environmental challenges linked to global climate change affecting these organisms. Understanding physiological trade-offs, especially those involving the immune system, will improve our understanding as to how corals could/will respond and survive in future adverse environmental conditions associated with climate change. PMID:25374778

  13. Physiology Of Drowning: A Review.

    PubMed

    Bierens, Joost J L M; Lunetta, Philippe; Tipton, Mike; Warner, David S

    2016-03-01

    Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning. PMID:26889019

  14. Physiologic regulation in electromagnetic fields

    SciTech Connect

    Michaelson, S.M.

    1982-01-01

    Electromagnetic fields have been demonstrated to elicit thermoregulatory responses, neuroendocrine, neurochemical modulations, and behavioral reactions. These physiologic regulatory processes are exquisitely tuned, interrelated functions that constitute sensitive indicators of organismic responses to radiofrequency energy absorption (the radiofrequency portion of the electromagnetic spectrum includes as one part microwaves). Assessment of the integration and correlation of these functions relative to the thermal inputs and homeokinetic reactions of the individual subjected to radiofrequency energy should permit differentiation between potential hazards that might compromise the individual's ability to maintain normal physiologic function and effects that are compensated by physiologic redundancy.

  15. Physiology of Sedentary Behavior and Its Relationship to Health Outcomes

    PubMed Central

    Thyfault, John P; Du, Mengmeng; Kraus, William E; Levine, James A; Booth, Frank W

    2014-01-01

    Purpose This paper reports on the findings and recommendations of the “Physiology of Sedentary Behavior and its Relationship to Health Outcomes” group, a part of a larger workshop entitled Sedentary Behavior: Identifying Research Priorities sponsored by the National Heart, and Lung and Blood Institute and the National Institute on Aging, which aimed to establish sedentary behavior research priorities. Methods The discussion within our workshop lead to the formation of critical physiological research objectives related to sedentary behaviors, that if appropriately researched would greatly impact our overall understanding of human health and longevity. Results and Conclusions Primary questions are related to physiological “health outcomes” including the influence of physical activity vs. sedentary behavior on function of a number of critical physiological systems (aerobic capacity, skeletal muscle metabolism and function, telomeres/genetic stability, and cognitive function). The group also derived important recommendations related to the “central and peripheral mechanisms” that govern sedentary behavior and how energy balance has a role in mediating these processes. General recommendations for future sedentary physiology research efforts include that studies of sedentary behavior, including that of sitting time only, should focus on the physiological impact of a “lack of human movement” in contradistinction to the effects of physical movement and that new models or strategies for studying sedentary behavior induced adaptations and links to disease development are needed to elucidate underlying mechanism(s). PMID:25222820

  16. Commercial Web Site Links.

    ERIC Educational Resources Information Center

    Thelwall, Mike

    2001-01-01

    Discusses business use of the Web and related search engine design issues as well as research on general and academic links before reporting on a survey of the links published by a collection of business Web sites. Results indicate around 66% of Web sites do carry external links, most of which are targeted at a specific purpose, but about 17%…

  17. Trophic links between functional groups of arable plants and beetles are stable at a national scale.

    PubMed

    Brooks, David R; Storkey, Jonathan; Clark, Suzanne J; Firbank, Les G; Petit, Sandrine; Woiwod, Ian P

    2012-01-01

    1. There is an urgent need to accurately model how environmental change affects the wide-scale functioning of ecosystems, but advances are hindered by a lack of knowledge of how trophic levels are linked across space. It is unclear which theoretical approach to take to improve modelling of such interactions, but evidence is gathering that linking species responses to their functional traits can increase understanding of ecosystem dynamics. Currently, there are no quantitative studies testing how this approach might improve models of multiple, trophically interacting species, at wide spatial scales. 2. Arable weeds play a foundational role in linking food webs, providing resources for many taxa, including carabid beetles that feed on their seeds and weed-associated invertebrate prey. Here, we model associations between weeds and carabids across farmland in Great Britain (GB), to test the hypothesis that wide-scale trophic links between these groups are structured by their species functional traits. 3. A network of c. 250 arable fields, covering four crops and most lowland areas of GB, was sampled for weed, carabid and invertebrate taxa over 3 years. Data sets of these groups were closely matched in time and space, and each contained numerous species with a range of eco-physiological traits. The consistency of trophic linkages between multiple taxa sharing functional traits was tested within multivariate and log-linear models. 4. Robust links were established between the functional traits of taxa and their trophic interactions. Autumn-germinating, small-seeded weeds were associated with smaller, spring-breeding carabids, more specialised in seed feeding, whereas spring-germinating, large-seeded weeds were associated with a range of larger, autumn-breeding omnivorous carabids. These relationships were strong and dynamic, being independent of changes in invertebrate food resources and consistent across sample dates, crops and regions of GB. 5. We conclude that, in at

  18. OLFACTION: ANATOMY, PHYSIOLOGY AND BEHAVIOR

    EPA Science Inventory

    The anatomy, physiology and function of the olfactory system are reviewed, as are the normal effects of olfactory stimulation. It is speculated that olfaction may have important but unobtrusive effects on human behavior.

  19. Physiological anthropology and the Internet.

    PubMed

    Karelović, D; Ognjenović, M; Cekić-Arambasin, A; Tadin, I

    1998-12-01

    The Internet is the greatest computer network with many services like Web, FTP, Gopher, E-mail Discussion Groups, and Usenet Discussion Groups, that provides a rapid and the cheapest exchange of information. The benefits to anthropologists of using the Internet are growing rapidly, as the Internet becomes easier to use and ever more anthropological resources become available on line. Physiological anthropology is concerned with the evolution and biological features of human population and it's sources on the Internet are growing continuously. However, in that enormous number of data, is not easy to find a needed information. Currently, number of indexed physiological anthropology related sites on Web only is 233990 (October 98). This paper provides informations about Internet and needed hardware and software for using it. It also describes and lists the most important physiological anthropology addresses, together with physiological anthropology-related journals on the Internet, as well as the ways of searching them. PMID:9951133

  20. Physiological Considerations of Artificial Gravity

    NASA Technical Reports Server (NTRS)

    Cramer, D. B.

    1985-01-01

    Reasons for the development of artificial gravity environments on spacecraft are outlined. The physiological effects of weightlessness on the human cardiovascular skeletal, and vestibular systems are enumerated. Design options for creating artificial gravity environments are shown.

  1. Physiological Functions of APP Family Proteins

    PubMed Central

    Müller, Ulrike C.; Zheng, Hui

    2012-01-01

    Biochemical and genetic evidence establishes a central role of the amyloid precursor protein (APP) in Alzheimer disease (AD) pathogenesis. Biochemically, deposition of the β-amyloid (Aβ) peptides produced from proteolytic processing of APP forms the defining pathological hallmark of AD; genetically, both point mutations and duplications of wild-type APP are linked to a subset of early onset of familial AD (FAD) and cerebral amyloid angiopathy. As such, the biological functions of APP and its processing products have been the subject of intense investigation, and the past 20+ years of research have met with both excitement and challenges. This article will review the current understanding of the physiological functions of APP in the context of APP family members. PMID:22355794

  2. Fundamental shift in vitamin B12 eco-physiology of a model alga demonstrated by experimental evolution

    PubMed Central

    Helliwell, Katherine E.; Collins, Sinéad; Kazamia, Elena; Purton, Saul; Wheeler, Glen L.; Smith, Alison G.

    2014-01-01

    A widespread and complex distribution of vitamin requirements exists over the entire tree of life, with many species having evolved vitamin dependence, both within and between different lineages. Vitamin availability has been proposed to drive selection for vitamin dependence, in a process that links an organism’s metabolism to the environment, but this has never been demonstrated directly. Moreover, understanding the physiological processes and evolutionary dynamics that influence metabolic demand for these important micronutrients has significant implications in terms of nutrient acquisition, and in microbial organisms, can affect community composition and metabolic exchange between coexisting species. Here, we investigate the origins of vitamin dependence, using an experimental evolution approach with the vitamin B12-independent model green alga Chlamydomonas reinhardtii. In fewer than 500 generations of growth in the presence of vitamin B12, we observe the evolution of a B12-dependent clone that rapidly displaces its ancestor. Genetic characterization of this line reveals a type-II Gulliver-related transposable element (GR-TE) integrated into the B12-independent methionine synthase gene (METE), knocking out gene function and critically altering the physiology of the alga. PMID:25526368

  3. The physiologic climate of Nigeria.

    PubMed

    Eludoyin, Oyenike Mary; Adelekan, Ibidun Onikepo

    2013-03-01

    This study describes the spatial and temporal variations in the physiologic climate of Nigeria for 1951-2009 in terms of effective temperature (ET), temperature-humidity index (THI), relative strain index (RSI) and perception of 3,600 sampled populations. The main hypotheses are that (i) the existing vegetation-based ecological region could adequately elucidate the physiologic climate of the country, and (ii) physiologic stress has significantly increased over the years (1951-2009). Trends and changes in the selected indices (ET, THI and RSI) were examined over two time slices: 1951-1980 and 1981-2009. The results show that (1) the montane region was the most comfortable physiologic climate in Nigeria, and the regions around the Rivers Niger and Benue troughs were the most uncomfortable in most parts of the year, (2) physiologic stress in most parts of Nigeria has significantly increased in 1981-2009 over 1951-1980 (p ≤ 0.05), (3) coping strategies to the uncomfortably hot and cold climate in Nigeria are limited to dressing mode, clothing materials and use of air conditioners or fan, (4) ET, THI and RSI results could be similar, and complementary; but each is with its strengths and weaknesses for annual or seasonal representations, which the others complemented for the interpretation of the physiologic climate of Nigeria. The study concluded that the relationship between the ecological classification of Nigeria and physiologic climate is rather complex, and the former could not elucidate the latter. The study cited inadequate meteorological data, especially on wind chill, and health records as limiting factors of studies on the Nigerian physiologic climates and the effect of extreme thermal conditions on the people. PMID:22610082

  4. The physiologic climate of Nigeria

    NASA Astrophysics Data System (ADS)

    Eludoyin, Oyenike Mary; Adelekan, Ibidun Onikepo

    2013-03-01

    This study describes the spatial and temporal variations in the physiologic climate of Nigeria for 1951-2009 in terms of effective temperature (ET), temperature-humidity index (THI), relative strain index (RSI) and perception of 3,600 sampled populations. The main hypotheses are that (i) the existing vegetation-based ecological region could adequately elucidate the physiologic climate of the country, and (ii) physiologic stress has significantly increased over the years (1951-2009). Trends and changes in the selected indices (ET, THI and RSI) were examined over two time slices: 1951-1980 and 1981-2009. The results show that (1) the montane region was the most comfortable physiologic climate in Nigeria, and the regions around the Rivers Niger and Benue troughs were the most uncomfortable in most parts of the year, (2) physiologic stress in most parts of Nigeria has significantly increased in 1981-2009 over 1951-1980 ( p ≤ 0.05), (3) coping strategies to the uncomfortably hot and cold climate in Nigeria are limited to dressing mode, clothing materials and use of air conditioners or fan, (4) ET, THI and RSI results could be similar, and complementary; but each is with its strengths and weaknesses for annual or seasonal representations, which the others complemented for the interpretation of the physiologic climate of Nigeria. The study concluded that the relationship between the ecological classification of Nigeria and physiologic climate is rather complex, and the former could not elucidate the latter. The study cited inadequate meteorological data, especially on wind chill, and health records as limiting factors of studies on the Nigerian physiologic climates and the effect of extreme thermal conditions on the people.

  5. Physiological Feedback Method and System

    NASA Technical Reports Server (NTRS)

    Pope, Alan T. (Inventor); Severance, Kurt E. (Inventor)

    2002-01-01

    A method and system provide physiological feedback for a patient and/or physician. At least one physiological effect experienced by a body part of a patient is measured noninvasively. A three-dimensional graphics model serving as an analogous representation of the body part is altered in accordance with the measurements. A binocular image signal representative of the three-dimensional graphics model so-altered is displayed for the patient and/or physician in a virtual reality environment.

  6. Regulatory physiology discipline science plan

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the Regulatory Physiology discipline of the Space Physiology and Countermeasures Program is twofold. First, to determine and study how microgravity and associated factors of space flight affect the regulatory mechanisms by which humans adapt and achieve homeostasis and thereby regulate their ability to respond to internal and external signals; and, second, to study selected physiological systems that have been demonstrated to be influenced by gravity. The Regulatory Physiology discipline, as defined here, is composed of seven subdisciplines: (1) Circadian Rhythms, (2) Endocrinology, (3) Fluid and Electrolyte Regulation, (4) Hematology, (5) Immunology, (6) Metabolism and Nutrition, and (7) Temperature Regulation. The purpose of this Discipline Science Plan is to provide a conceptual strategy for NASA's Life Sciences Division research and development activities in the area of regulatory physiology. It covers the research areas critical to NASA's programmatic requirements for the Extended-Duration Orbiter, Space Station Freedom, and exploration mission science activities. These science activities include ground-based and flight; basic, applied, and operational; and animal and human research and development. This document summarizes the current status of the program, outlines available knowledge, establishes goals and objectives, identifies science priorities, and defines critical questions in regulatory physiology. It contains a general plan that will be used by both NASA Headquarters Program Offices and the field centers to review and plan basic, applied, and operational intramural and extramural research and development activities in this area.

  7. Marine Microbial Secondary Metabolites: Pathways, Evolution and Physiological Roles.

    PubMed

    Giordano, Daniela; Coppola, Daniela; Russo, Roberta; Denaro, Renata; Giuliano, Laura; Lauro, Federico M; di Prisco, Guido; Verde, Cinzia

    2015-01-01

    Microbes produce a huge array of secondary metabolites endowed with important ecological functions. These molecules, which can be catalogued as natural products, have long been exploited in medical fields as antibiotics, anticancer and anti-infective agents. Recent years have seen considerable advances in elucidating natural-product biosynthesis and many drugs used today are natural products or natural-product derivatives. The major contribution to recent knowledge came from application of genomics to secondary metabolism and was facilitated by all relevant genes being organised in a contiguous DNA segment known as gene cluster. Clustering of genes regulating biosynthesis in bacteria is virtually universal. Modular gene clusters can be mixed and matched during evolution to generate structural diversity in natural products. Biosynthesis of many natural products requires the participation of complex molecular machines known as polyketide synthases and non-ribosomal peptide synthetases. Discovery of new evolutionary links between the polyketide synthase and fatty acid synthase pathways may help to understand the selective advantages that led to evolution of secondary-metabolite biosynthesis within bacteria. Secondary metabolites confer selective advantages, either as antibiotics or by providing a chemical language that allows communication among species, with other organisms and their environment. Herewith, we discuss these aspects focusing on the most clinically relevant bioactive molecules, the thiotemplated modular systems that include polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. We begin by describing the evolutionary and physiological role of marine natural products, their structural/functional features, mechanisms of action and biosynthesis, then turn to genomic and metagenomic approaches, highlighting how the growing body of information on microbial natural products can be used to address fundamental problems in

  8. Amateur boxing: physical and physiological attributes.

    PubMed

    Chaabène, Helmi; Tabben, Montassar; Mkaouer, Bessem; Franchini, Emerson; Negra, Yassine; Hammami, Mehrez; Amara, Samiha; Chaabène, Raja Bouguezzi; Hachana, Younés

    2015-03-01

    Boxing is one of the oldest combat sports. The aim of the current review is to critically analyze the amateur boxer's physical and physiological characteristics and to provide practical recommendations for training as well as new areas of scientific research. High-level male and female boxers show a propensity for low body fat levels. Although studies on boxer somatotypes are limited, the available information shows that elite-level male boxers are characterized by a higher proportion of mesomorphy with a well-developed muscle mass and a low body fat level. To help support the overall metabolic demands of a boxing match and to accelerate the recovery process between rounds, athletes of both sexes require a high level of cardiorespiratory fitness. International boxers show a high peak and mean anaerobic power output. Muscle strength in both the upper and lower limbs is paramount for a fighter's victory and is one of the keys to success in boxing. As boxing punches are brief actions and very dynamic, high-level boxing performance requires well-developed muscle power in both the upper and lower limbs. Albeit limited, the available studies reveal that isometric strength is linked to high-level boxing performance. Future investigations into the physical and physiological attributes of boxers are required to enrich the current data set and to help create a suitable training program. PMID:25358529

  9. Hedgehogs and sugar gliders: respiratory anatomy, physiology, and disease.

    PubMed

    Johnson, Dan H

    2011-05-01

    This article discusses the respiratory anatomy, physiology, and disease of African pygmy hedgehogs (Atelerix albiventris) and sugar gliders (Petaurus breviceps), two species commonly seen in exotic animal practice. Where appropriate, information from closely related species is mentioned because cross-susceptibility is likely and because these additional species may also be encountered in practice. Other body systems and processes are discussed insofar as they relate to or affect respiratory function. Although some topics, such as special senses, hibernation, or vocalization, may seem out of place, in each case the information relates back to respiration in some important way. PMID:21601815

  10. Geobacter: the microbe electric's physiology, ecology, and practical applications.

    PubMed

    Lovley, Derek R; Ueki, Toshiyuki; Zhang, Tian; Malvankar, Nikhil S; Shrestha, Pravin M; Flanagan, Kelly A; Aklujkar, Muktak; Butler, Jessica E; Giloteaux, Ludovic; Rotaru, Amelia-Elena; Holmes, Dawn E; Franks, Ashley E; Orellana, Roberto; Risso, Carla; Nevin, Kelly P

    2011-01-01

    Geobacter species specialize in making electrical contacts with extracellular electron acceptors and other organisms. This permits Geobacter species to fill important niches in a diversity of anaerobic environments. Geobacter species appear to be the primary agents for coupling the oxidation of organic compounds to the reduction of insoluble Fe(III) and Mn(IV) oxides in many soils and sediments, a process of global biogeochemical significance. Some Geobacter species can anaerobically oxidize aromatic hydrocarbons and play an important role in aromatic hydrocarbon removal from contaminated aquifers. The ability of Geobacter species to reductively precipitate uranium and related contaminants has led to the development of bioremediation strategies for contaminated environments. Geobacter species produce higher current densities than any other known organism in microbial fuel cells and are common colonizers of electrodes harvesting electricity from organic wastes and aquatic sediments. Direct interspecies electron exchange between Geobacter species and syntrophic partners appears to be an important process in anaerobic wastewater digesters. Functional and comparative genomic studies have begun to reveal important aspects of Geobacter physiology and regulation, but much remains unexplored. Quantifying key gene transcripts and proteins of subsurface Geobacter communities has proven to be a powerful approach to diagnose the in situ physiological status of Geobacter species during groundwater bioremediation. The growth and activity of Geobacter species in the subsurface and their biogeochemical impact under different environmental conditions can be predicted with a systems biology approach in which genome-scale metabolic models are coupled with appropriate physical/chemical models. The proficiency of Geobacter species in transferring electrons to insoluble minerals, electrodes, and possibly other microorganisms can be attributed to their unique "microbial nanowires," pili

  11. Symbiotic physiology promotes homeostasis in Daisyworld.

    PubMed

    Boyle, Richard A; Lenton, Timothy M; Watson, Andrew J

    2011-04-01

    A connection is hypothesized between the physiological consequences of mutualistic symbiosis and life's average long-term impact on certain highly biologically conserved environmental variables. This hypothesis is developed analytically and with a variant of the Daisyworld model. Biological homeostasis is frequently effective due to co-ordination between opposing physiological "rein" functions, which buffer an organism in response to an external (often environmental) perturbation. It is proposed that during evolutionary history the pooling of different species' physiological functions in mutualistic symbioses increased the range of suboptimal environmental conditions that could be buffered against--a mutual tolerance benefit sometimes sufficient to outweigh the cost of cooperation. A related argument is that for a small number of biologically-crucial physical variables (i) the difference between organism interiors and the life-environment interface is relatively low, and (ii) the biologically optimum level of that variable is relatively highly conserved across different species. For such variables, symbiosis tends to cause (at a cost) an increase in the number of environmental buffering functions per unit of selection, which in turn biases the overall impact of the biota on the state of the variable towards the biological optimum. When a costly but more temperature-tolerant and physiologically versatile symbiosis between one black (warming) and one white (cooling) "daisy" is added to the (otherwise unaltered) Daisyworld parable, four new results emerge: (1) The extension of habitability to a wider luminosity range, (2) resistance to the impact of "cheater" white daisies with cold optima, that derive short-term benefit from environmental destabilisation, (3) the capacity to maintain residual, oscillatory regulation in response to forcings that change more rapidly than allele frequencies and (crucially) (4) "succession"-type dynamics in which the tolerant symbiosis