Coping with thermal challenges: physiological adaptations to environmental temperatures.

PubMed

Tattersall, Glenn J; Sinclair, Brent J; Withers, Philip C; Fields, Peter A; Seebacher, Frank; Cooper, Christine E; Maloney, Shane K

2012-07-01

Temperature profoundly influences physiological responses in animals, primarily due to the effects on biochemical reaction rates. Since physiological responses are often exemplified by their rate dependency (e.g., rate of blood flow, rate of metabolism, rate of heat production, and rate of ion pumping), the study of temperature adaptations has a long history in comparative and evolutionary physiology. Animals may either defend a fairly constant temperature by recruiting biochemical mechanisms of heat production and utilizing physiological responses geared toward modifying heat loss and heat gain from the environment, or utilize biochemical modifications to allow for physiological adjustments to temperature. Biochemical adaptations to temperature involve alterations in protein structure that compromise the effects of increased temperatures on improving catalytic enzyme function with the detrimental influences of higher temperature on protein stability. Temperature has acted to shape the responses of animal proteins in manners that generally preserve turnover rates at animals' normal, or optimal, body temperatures. Physiological responses to cold and warmth differ depending on whether animals maintain elevated body temperatures (endothermic) or exhibit minimal internal heat production (ectothermic). In both cases, however, these mechanisms involve regulated neural and hormonal over heat flow to the body or heat flow within the body. Examples of biochemical responses to temperature in endotherms involve metabolic uncoupling mechanisms that decrease metabolic efficiency with the outcome of producing heat, whereas ectothermic adaptations to temperature are best exemplified by the numerous mechanisms that allow for the tolerance or avoidance of ice crystal formation at temperatures below 0°C. 2012 American Physiological Society. Compr Physiol 2:2037-2061, 2012.

Complexity and network dynamics in physiological adaptation: an integrated view.

PubMed

Baffy, György; Loscalzo, Joseph

2014-05-28

Living organisms constantly interact with their surroundings and sustain internal stability against perturbations. This dynamic process follows three fundamental strategies (restore, explore, and abandon) articulated in historical concepts of physiological adaptation such as homeostasis, allostasis, and the general adaptation syndrome. These strategies correspond to elementary forms of behavior (ordered, chaotic, and static) in complex adaptive systems and invite a network-based analysis of the operational characteristics, allowing us to propose an integrated framework of physiological adaptation from a complex network perspective. Applicability of this concept is illustrated by analyzing molecular and cellular mechanisms of adaptation in response to the pervasive challenge of obesity, a chronic condition resulting from sustained nutrient excess that prompts chaotic exploration for system stability associated with tradeoffs and a risk of adverse outcomes such as diabetes, cardiovascular disease, and cancer. Deconstruction of this complexity holds the promise of gaining novel insights into physiological adaptation in health and disease. Published by Elsevier Inc.

From genotype to phenotype: unraveling the complexities of cold adaptation in forest trees

Treesearch

Glenn T. Howe; Sally N. Aitken; David B. Neale; Kathleen D. Jermstad; Nicholas C. Wheeler; Tony H.H Chen

2003-01-01

Adaptation to winter cold in temperate and boreal trees involves complex genetic, physiological, and developmental processes. Genecological studies demonstrate the existence of steep genetic clines for cold adaptation traits in relation to environmental (mostly temperature related) gradients. Population differentiation is generally stronger for cold adaptation traits...

Physiology-driven adaptive virtual reality stimulation for prevention and treatment of stress related disorders.

PubMed

Cosić, Kresimir; Popović, Sinisa; Kukolja, Davor; Horvat, Marko; Dropuljić, Branimir

2010-02-01

The significant proportion of severe psychological problems related to intensive stress in recent large peacekeeping operations underscores the importance of effective methods for strengthening the prevention and treatment of stress-related disorders. Adaptive control of virtual reality (VR) stimulation presented in this work, based on estimation of the person's emotional state from physiological signals, may enhance existing stress inoculation training (SIT). Physiology-driven adaptive VR stimulation can tailor the progress of stressful stimuli delivery to the physiological characteristics of each individual, which is indicated for improvement in stress resistance. Following an overview of physiology-driven adaptive VR stimulation, its major functional subsystems are described in more detail. A specific algorithm of stimuli delivery applicable to SIT is outlined.

Global analysis of genes involved in freshwater adaptation in threespine sticklebacks (Gasterosteus aculeatus).

PubMed

DeFaveri, Jacquelin; Shikano, Takahito; Shimada, Yukinori; Goto, Akira; Merilä, Juha

2011-06-01

Examples of parallel evolution of phenotypic traits have been repeatedly demonstrated in threespine sticklebacks (Gasterosteus aculeatus) across their global distribution. Using these as a model, we performed a targeted genome scan--focusing on physiologically important genes potentially related to freshwater adaptation--to identify genetic signatures of parallel physiological evolution on a global scale. To this end, 50 microsatellite loci, including 26 loci within or close to (<6 kb) physiologically important genes, were screened in paired marine and freshwater populations from six locations across the Northern Hemisphere. Signatures of directional selection were detected in 24 loci, including 17 physiologically important genes, in at least one location. Although no loci showed consistent signatures of selection in all divergent population pairs, several outliers were common in multiple locations. In particular, seven physiologically important genes, as well as reference ectodysplasin gene (EDA), showed signatures of selection in three or more locations. Hence, although these results give some evidence for consistent parallel molecular evolution in response to freshwater colonization, they suggest that different evolutionary pathways may underlie physiological adaptation to freshwater habitats within the global distribution of the threespine stickleback. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Relationship of psychological and physiological parameters during an arctic ski expedition

NASA Astrophysics Data System (ADS)

Bishop, Sheryl L.; Grobler, Lukas C.; SchjØll, Olaf

2001-08-01

Considerable data (primarily physiological) have been collected during expeditions in extreme environments over the last century. Physiological measurements have only recently been examined in association with the emotional or behavioral state of the subject. Establishing this psychophysiological relationship is essential to understanding fully the adaptation of humans to the stresses of extreme environments. This pilot study investigated the simultaneous collection of physiological, psychological and behavioral data from a two-man Greenland expedition in order to model how specific relationships between physiological and psychological adaptation to a polar environment may be identified. The data collected describes changes in adrenal and other hormonal activity and psychological functioning. Levels of cortisol and testosterone were calculated. Factors influencing the plasma profiles of the aforementioned included 24-hour sunlight, high calorific intake of more than 28 000 kJ/day and extreme physical exercise. There was a difference between individual psychological profiles as well as self-report stress and physiological stress.

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.

Gravitational adaptation of animals

NASA Technical Reports Server (NTRS)

Smith, A. H.; Burton, R. R.

1982-01-01

The effect of gravitational adaptation is studied in a group of five Leghorn cocks which had become physiologically adapted to 2 G after 162 days of centrifugation. After this period of adaptation, they are periodically exposed to a 2 G field, accompanied by five previously unexposed hatch-mates, and the degree of retained acceleration adaptation is estimated from the decrease in lymphocyte frequency after 24 hr at 2 G. Results show that the previously adapted birds exhibit an 84% greater lymphopenia than the unexposed birds, and that the lymphocyte frequency does not decrease to a level below that found at the end of 162 days at 2 G. In addition, the capacity for adaptation to chronic acceleration is found to be highly heritable. An acceleration tolerant strain of birds shows lesser mortality during chronic acceleration, particularly in intermediate fields, although the result of acceleration selection is largely quantitative (a greater number of survivors) rather than qualitative (behavioral or physiological changes).

Ecophysiological adaptations of anaerobic bacteria to low pH. [Sarcina ventriculi; Lactobacillus helveticus

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

Goodwin, S.D.

1986-01-01

The ecological and physiological adaptations of anaerobic bacteria to low pH were investigated in field and laboratory studies. Determinations of hydrogen kinetic parameters demonstrated that overall hydrogen metabolism was inhibited in acid ecosystems. In particular, hydrogen metabolism became progressively uncoupled at low pH. This uncoupling resulted in a slowing of carbon flow during anaerobic digestion and the accumulation of intermediary metabolites. The addition of carbon electron donors to acid bog sediments resulted in the accumulation of hydrogen and a slowing of the overall rates of anaerobic digestion. As an adaptation to low pH, anaerobic bacterial populations shifted from production ofmore » acid intermediary metabolites (e.g. acetate and lactate) to the production of neutral intermediary metabolites (e.g. ethanol). This shift was observed both in situ and in pure cultures of hydrolytic strains isolated from bog sediments. Detailed physiological studies of Sarcina ventriculi showed an adaptation to growth at low pH by mechanisms which allowed the continued production of ethanol from glucose and the maintenance of a proton motive force at low cytoplasmic pH values. Further physiological studies Lactobacillus helveticus showed that the accumulation of acidic end-product (lactic acid) strongly influenced cellular electrochemical parameters. Based on the results of computer simulations and laboratory studies of the physiology of the organism in the presence of organic acids, a new model for the passive coupling of energy conservation to the efflux of lactic acid in an electroneutral process is proposed.« less

Physiology of man and animals in the Tenth Five-Year Plan: Proceedings of the Thirteenth Congress of the I. P. Pavlov All-Union Physiological Society

NASA Technical Reports Server (NTRS)

Lange, K. A.

1980-01-01

Research in the field of animal and human physiology is reviewed. The following topics on problems of physiological science and related fields of knowledge are discussed: neurophysiology and higher nervous activity, physiology of sensory systems, physiology of visceral systems, evolutionary and ecological physiology, physiological cybernetics, computer application in physiology, information support of physiological research, history and theory of development of physiology. Also discussed were: artificial intelligence, physiological problems of reflex therapy, correlation of structure and function of the brain, adaptation and activity, microcirculation, and physiological studies in nerve and mental diseases.

Resistance Training: Physiological Responses and Adaptations (Part 2 of 4).

ERIC Educational Resources Information Center

Fleck, Stephen J.; Kraerner, William J.

1988-01-01

Resistance training causes a variety of physiological reactions, including changes in muscle size, connective tissue size, and bone mineral content. This article summarizes data from a variety of studies and research. (JL)

Physiology modulates social flexibility and collective behaviour in equids and other large ungulates.

PubMed

Gersick, Andrew S; Rubenstein, Daniel I

2017-08-19

Though morphologically very similar, equids across the extant species occupy ecological niches that are surprisingly non-overlapping. Occupancy of these distinct niches appears related to subtle physiological and behavioural adaptations which, in turn, correspond to significant differences in the social behaviours and emergent social systems characterizing the different species. Although instances of intraspecific behavioural variation in equids demonstrate that the same body plan can support a range of social structures, each of these morphologically similar species generally shows robust fidelity to its evolved social system. The pattern suggests a subtle relationship between physiological phenotypes and behavioural flexibility. While environmental conditions can vary widely within relatively short temporal or spatial scales, physiological changes and changes to the behaviours that regulate physiological processes, are constrained to longer cycles of adaptation. Physiology is then the limiting variable in the interaction between ecological variation and behavioural and socio-structural flexibility. Behavioural and socio-structural flexibility, in turn, will generate important feedbacks that will govern physiological function, thus creating a coupled web of interactions that can lead to changes in individual and collective behaviour. Longitudinal studies of equid and other large-bodied ungulate populations under environmental stress, such as those discussed here, may offer the best opportunities for researchers to examine, in real time, the interplay between individual behavioural plasticity, socio-structural flexibility, and the physiological and genetic changes that together produce adaptive change.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'. © 2017 The Author(s).

Resistance Training: Physiological Responses and Adaptations (Part 3 of 4).

ERIC Educational Resources Information Center

Fleck, Steven J.; Kraemer, William J.

1988-01-01

The physiological responses and adaptations which occur as a result of resistance training, such as cardiovascular responses, serum lipid count, body composition, and neural adaptations are discussed. Changes in the endocrine system are also described. (JL)

Gene expression changes in the coccolithophore Emiliania huxleyi after 500 generations of selection to ocean acidification

PubMed Central

Lohbeck, Kai T.; Riebesell, Ulf; Reusch, Thorsten B. H.

2014-01-01

Coccolithophores are unicellular marine algae that produce biogenic calcite scales and substantially contribute to marine primary production and carbon export to the deep ocean. Ongoing ocean acidification particularly impairs calcifying organisms, mostly resulting in decreased growth and calcification. Recent studies revealed that the immediate physiological response in the coccolithophore Emiliania huxleyi to ocean acidification may be partially compensated by evolutionary adaptation, yet the underlying molecular mechanisms are currently unknown. Here, we report on the expression levels of 10 candidate genes putatively relevant to pH regulation, carbon transport, calcification and photosynthesis in E. huxleyi populations short-term exposed to ocean acidification conditions after acclimation (physiological response) and after 500 generations of high CO2 adaptation (adaptive response). The physiological response revealed downregulation of candidate genes, well reflecting the concomitant decrease of growth and calcification. In the adaptive response, putative pH regulation and carbon transport genes were up-regulated, matching partial restoration of growth and calcification in high CO2-adapted populations. Adaptation to ocean acidification in E. huxleyi likely involved improved cellular pH regulation, presumably indirectly affecting calcification. Adaptive evolution may thus have the potential to partially restore cellular pH regulatory capacity and thereby mitigate adverse effects of ocean acidification. PMID:24827439

Switching between pitch surfaces: practical applications and future perspectives for soccer training.

PubMed

Rago, Vincenzo; Silva, João R; Brito, João; Barreira, Daniel; Mohr, Magni; Krustrup, Peter; Rebelo, António N

2018-04-04

Soccer training and completion is conventionally practiced on natural grass (NG) or artificial turf (AT). Recently, AT pitches for training / competition, and of unstable surfaces for injury prevention training has increased. Therefore, soccer players are frequently exposed to variations in pitch surface during either training or competition. These ground changes may impact physical and physiological responses, adaptations as well as the injury. The aim of this review was to summarize the acute physical and physiological responses, chronic adaptations, and injury risk associated with exercising on different pitch surfaces in soccer. Eligible studies were published in English, had pitch surface as an independent variable, and had physical, physiological or epidemiological information as outcome variables. Specific data extracted from the articles included the training response, training adaptations or injury outcomes according to different pitch surfaces. A total of 224 studies were retrieved from a literature search. Twenty articles met the inclusion criteria: 9 for acute physical and physiological responses, 2 for training adaptations and 9 for injury assessment. The literature lacks consistent evidence regarding the effects of pitch surface on performance and health outcomes in soccer players. However, it seems that occasionally switching training surfaces seems a valuable strategy for focusing on specific musculoskeletal queries and enhancing players' fitness. For instance, sand training may be occasionally proposed as complementary training strategy, given the recruitment of additional musculature probably not involved on firmer surfaces, but the possible training-induced adaptations of non-conventional soccer surfaces (e.g., sand) might potentially result into a negative transfer on AT or NG. Since the specific physical demands of soccer can differ between surfaces, coaches should resort to the use of non-traditional surfaces with parsimony, emphasizing the specific surface-related motor tasks, normally observed on natural grass or artificial turf. Further studies are required to better understand the physiological effects induced by systematic surface-specific training, or switching between pitch surfaces.

Genetics and the physiological ecology of conifers

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

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 themore » 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.« less

The Burmese python genome reveals the molecular basis for extreme adaptation in snakes

PubMed Central

Castoe, Todd A.; de Koning, A. P. Jason; Hall, Kathryn T.; Card, Daren C.; Schield, Drew R.; Fujita, Matthew K.; Ruggiero, Robert P.; Degner, Jack F.; Daza, Juan M.; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J.; Castoe, Jill M.; Fox, Samuel E.; Poole, Alex W.; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W.; Li, Qing; Schott, Ryan K.; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A.; Hoffmann, Federico G.; Bogden, Robert; Smith, Eric N.; Chang, Belinda S. W.; Vonk, Freek J.; Casewell, Nicholas R.; Henkel, Christiaan V.; Richardson, Michael K.; Mackessy, Stephen P.; Bronikowski, Anne M.; Yandell, Mark; Warren, Wesley C.; Secor, Stephen M.; Pollock, David D.

2013-01-01

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome. PMID:24297902

The Burmese python genome reveals the molecular basis for extreme adaptation in snakes.

PubMed

Castoe, Todd A; de Koning, A P Jason; Hall, Kathryn T; Card, Daren C; Schield, Drew R; Fujita, Matthew K; Ruggiero, Robert P; Degner, Jack F; Daza, Juan M; Gu, Wanjun; Reyes-Velasco, Jacobo; Shaney, Kyle J; Castoe, Jill M; Fox, Samuel E; Poole, Alex W; Polanco, Daniel; Dobry, Jason; Vandewege, Michael W; Li, Qing; Schott, Ryan K; Kapusta, Aurélie; Minx, Patrick; Feschotte, Cédric; Uetz, Peter; Ray, David A; Hoffmann, Federico G; Bogden, Robert; Smith, Eric N; Chang, Belinda S W; Vonk, Freek J; Casewell, Nicholas R; Henkel, Christiaan V; Richardson, Michael K; Mackessy, Stephen P; Bronikowski, Anne M; Bronikowsi, Anne M; Yandell, Mark; Warren, Wesley C; Secor, Stephen M; Pollock, David D

2013-12-17

Snakes possess many extreme morphological and physiological adaptations. Identification of the molecular basis of these traits can provide novel understanding for vertebrate biology and medicine. Here, we study snake biology using the genome sequence of the Burmese python (Python molurus bivittatus), a model of extreme physiological and metabolic adaptation. We compare the python and king cobra genomes along with genomic samples from other snakes and perform transcriptome analysis to gain insights into the extreme phenotypes of the python. We discovered rapid and massive transcriptional responses in multiple organ systems that occur on feeding and coordinate major changes in organ size and function. Intriguingly, the homologs of these genes in humans are associated with metabolism, development, and pathology. We also found that many snake metabolic genes have undergone positive selection, which together with the rapid evolution of mitochondrial proteins, provides evidence for extensive adaptive redesign of snake metabolic pathways. Additional evidence for molecular adaptation and gene family expansions and contractions is associated with major physiological and phenotypic adaptations in snakes; genes involved are related to cell cycle, development, lungs, eyes, heart, intestine, and skeletal structure, including GRB2-associated binding protein 1, SSH, WNT16, and bone morphogenetic protein 7. Finally, changes in repetitive DNA content, guanine-cytosine isochore structure, and nucleotide substitution rates indicate major shifts in the structure and evolution of snake genomes compared with other amniotes. Phenotypic and physiological novelty in snakes seems to be driven by system-wide coordination of protein adaptation, gene expression, and changes in the structure of the genome.

Boldness behavior and stress physiology in a novel urban environment suggest rapid correlated evolutionary adaptation

PubMed Central

Cardoso, Gonçalo C.; Whittaker, Danielle J.; Campbell-Nelson, Samuel; Robertson, Kyle W.; Ketterson, Ellen D.

2012-01-01

Novel or changing environments expose animals to diverse stressors that likely require coordinated hormonal and behavioral adaptations. Predicted adaptations to urban environments include attenuated physiological responses to stressors and bolder exploratory behaviors, but few studies to date have evaluated the impact of urban life on codivergence of these hormonal and behavioral traits in natural systems. Here, we demonstrate rapid adaptive shifts in both stress physiology and correlated boldness behaviors in a songbird, the dark-eyed junco, following its colonization of a novel urban environment. We compared elevation in corticosterone (CORT) in response to handling and flight initiation distances in birds from a recently established urban population in San Diego, California to birds from a nearby wildland population in the species' ancestral montane breeding range. We also measured CORT and exploratory behavior in birds raised from early life in a captive common garden study. We found persistent population differences for both reduced CORT responses and bolder exploratory behavior in birds from the colonist population, as well as significant negative covariation between maximum CORT and exploratory behavior. Although early developmental effects cannot be ruled out, these results suggest contemporary adaptive evolution of correlated hormonal and behavioral traits associated with colonization of an urban habitat. PMID:22936840

Boldness behavior and stress physiology in a novel urban environment suggest rapid correlated evolutionary adaptation.

PubMed

Atwell, Jonathan W; Cardoso, Gonçalo C; Whittaker, Danielle J; Campbell-Nelson, Samuel; Robertson, Kyle W; Ketterson, Ellen D

2012-09-01

Novel or changing environments expose animals to diverse stressors that likely require coordinated hormonal and behavioral adaptations. Predicted adaptations to urban environments include attenuated physiological responses to stressors and bolder exploratory behaviors, but few studies to date have evaluated the impact of urban life on codivergence of these hormonal and behavioral traits in natural systems. Here, we demonstrate rapid adaptive shifts in both stress physiology and correlated boldness behaviors in a songbird, the dark-eyed junco, following its colonization of a novel urban environment. We compared elevation in corticosterone (CORT) in response to handling and flight initiation distances in birds from a recently established urban population in San Diego, California to birds from a nearby wildland population in the species' ancestral montane breeding range. We also measured CORT and exploratory behavior in birds raised from early life in a captive common garden study. We found persistent population differences for both reduced CORT responses and bolder exploratory behavior in birds from the colonist population, as well as significant negative covariation between maximum CORT and exploratory behavior. Although early developmental effects cannot be ruled out, these results suggest contemporary adaptive evolution of correlated hormonal and behavioral traits associated with colonization of an urban habitat.

The Mammalian Diving Response: An Enigmatic Reflex to Preserve Life?

PubMed Central

2013-01-01

The mammalian diving response is a remarkable behavior that overrides basic homeostatic reflexes. It is most studied in large aquatic mammals but is seen in all vertebrates. Pelagic mammals have developed several physiological adaptations to conserve intrinsic oxygen stores, but the apnea, bradycardia, and vasoconstriction is shared with those terrestrial and is neurally mediated. The adaptations of aquatic mammals are reviewed here as well as the neural control of cardiorespiratory physiology during diving in rodents. PMID:23997188

A cell biologist's perspective on physiological adaptation to opiate drugs.

PubMed

von Zastrow, Mark

2004-01-01

Opiate drugs such as morphine and heroin are among the most effective analgesics known but are also highly addictive. The clinical utility of opiates is limited by adaptive changes in the nervous system occurring after prolonged or repeated drug administration. These adaptations are believed to play an important role in the development of physiological tolerance and dependence to opiates, and to contribute to additional changes underlying the complex neurobehavioral syndrome of drug addiction. All of these adaptive changes are initiated by the binding of opiate drugs to a subfamily of G protein-coupled receptors that are also activated by endogenously produced opioid neuropeptides. It is increasingly evident that opiate-induced adaptations occur at multiple levels in the nervous system, beginning with regulation of opioid receptors themselves and extending to a complex network of direct and indirect modifications of "downstream" signaling machinery. Efforts in my laboratory are directed at understanding the biochemical and cell biological basis of opiate adaptations. So far, we have focused primarily on adaptations occurring at the level of opioid receptors themselves. These studies have contributed to defining a set of membrane trafficking mechanisms by which the number and functional activity of opioid receptors are controlled. The role of these mechanisms in affecting adaptation of "downstream" neurobiological substrates, and in mediating opiate-induced changes in whole-animal physiology and behavior, are exciting questions that are only beginning to be explored.

Human whole body cold adaptation.

PubMed

Daanen, Hein A M; Van Marken Lichtenbelt, Wouter D

2016-01-01

Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold.

Human whole body cold adaptation

PubMed Central

Daanen, Hein A.M.; Van Marken Lichtenbelt, Wouter D.

2016-01-01

ABSTRACT Reviews on whole body human cold adaptation generally do not distinguish between population studies and dedicated acclimation studies, leading to confusing results. Population studies show that indigenous black Africans have reduced shivering thermogenesis in the cold and poor cold induced vasodilation in fingers and toes compared to Caucasians and Inuit. About 40,000 y after humans left Africa, natives in cold terrestrial areas seems to have developed not only behavioral adaptations, but also physiological adaptations to cold. Dedicated studies show that repeated whole body exposure of individual volunteers, mainly Caucasians, to severe cold results in reduced cold sensation but no major physiological changes. Repeated cold water immersion seems to slightly reduce metabolic heat production, while repeated exposure to milder cold conditions shows some increase in metabolic heat production, in particular non-shivering thermogenesis. In conclusion, human cold adaptation in the form of increased metabolism and insulation seems to have occurred during recent evolution in populations, but cannot be developed during a lifetime in cold conditions as encountered in temperate and arctic regions. Therefore, we mainly depend on our behavioral skills to live in and survive the cold. PMID:27227100

Psychrophiles

NASA Astrophysics Data System (ADS)

Siddiqui, Khawar S.; Williams, Timothy J.; Wilkins, David; Yau, Sheree; Allen, Michelle A.; Brown, Mark V.; Lauro, Federico M.; Cavicchioli, Ricardo

2013-05-01

Psychrophilic (cold-adapted) microorganisms make a major contribution to Earth's biomass and perform critical roles in global biogeochemical cycles. The vast extent and environmental diversity of Earth's cold biosphere has selected for equally diverse microbial assemblages that can include archaea, bacteria, eucarya, and viruses. Underpinning the important ecological roles of psychrophiles are exquisite mechanisms of physiological adaptation. Evolution has also selected for cold-active traits at the level of molecular adaptation, and enzymes from psychrophiles are characterized by specific structural, functional, and stability properties. These characteristics of enzymes from psychrophiles not only manifest in efficient low-temperature activity, but also result in a flexible protein structure that enables biocatalysis in nonaqueous solvents. In this review, we examine the ecology of Antarctic psychrophiles, physiological adaptation of psychrophiles, and properties of cold-adapted proteins, and we provide a view of how these characteristics inform studies of astrobiology.

Genetic dissection of the Arabidopsis spaceflight transcriptome: Are some responses dispensable for the physiological adaptation of plants to spaceflight?

PubMed Central

Sng, Natasha J.; Zupanska, Agata K.; Krishnamurthy, Aparna; Schultz, Eric R.; Ferl, Robert J.

2017-01-01

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response than Col-0, suggesting that the in-space light environment affects physiological adaptation, which implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation. PMID:28662188

Genetic dissection of the Arabidopsis spaceflight transcriptome: Are some responses dispensable for the physiological adaptation of plants to spaceflight?

PubMed

Paul, Anna-Lisa; Sng, Natasha J; Zupanska, Agata K; Krishnamurthy, Aparna; Schultz, Eric R; Ferl, Robert J

2017-01-01

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response than Col-0, suggesting that the in-space light environment affects physiological adaptation, which implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation.

Metabolic Adaptation to Muscle Ischemia

NASA Technical Reports Server (NTRS)

Cabrera, Marco E.; Coon, Jennifer E.; Kalhan, Satish C.; Radhakrishnan, Krishnan; Saidel, Gerald M.; Stanley, William C.

2000-01-01

Although all tissues in the body can adapt to varying physiological/pathological conditions, muscle is the most adaptable. To understand the significance of cellular events and their role in controlling metabolic adaptations in complex physiological systems, it is necessary to link cellular and system levels by means of mechanistic computational models. The main objective of this work is to improve understanding of the regulation of energy metabolism during skeletal/cardiac muscle ischemia by combining in vivo experiments and quantitative models of metabolism. Our main focus is to investigate factors affecting lactate metabolism (e.g., NADH/NAD) and the inter-regulation between carbohydrate and fatty acid metabolism during a reduction in regional blood flow. A mechanistic mathematical model of energy metabolism has been developed to link cellular metabolic processes and their control mechanisms to tissue (skeletal muscle) and organ (heart) physiological responses. We applied this model to simulate the relationship between tissue oxygenation, redox state, and lactate metabolism in skeletal muscle. The model was validated using human data from published occlusion studies. Currently, we are investigating the difference in the responses to sudden vs. gradual onset ischemia in swine by combining in vivo experimental studies with computational models of myocardial energy metabolism during normal and ischemic conditions.

Oxidative stress adaptation with acute, chronic, and repeated stress.

PubMed

Pickering, Andrew M; Vojtovich, Lesya; Tower, John; A Davies, Kelvin J

2013-02-01

Oxidative stress adaptation, or hormesis, is an important mechanism by which cells and organisms respond to, and cope with, environmental and physiological shifts in the level of oxidative stress. Most studies of oxidative stress adaption have been limited to adaptation induced by acute stress. In contrast, many if not most environmental and physiological stresses are either repeated or chronic. In this study we find that both cultured mammalian cells and the fruit fly Drosophila melanogaster are capable of adapting to chronic or repeated stress by upregulating protective systems, such as their proteasomal proteolytic capacity to remove oxidized proteins. Repeated stress adaptation resulted in significant extension of adaptive responses. Repeated stresses must occur at sufficiently long intervals, however (12-h or more for MEF cells and 7 days or more for flies), for adaptation to be successful, and the levels of both repeated and chronic stress must be lower than is optimal for adaptation to acute stress. Regrettably, regimens of adaptation to both repeated and chronic stress that were successful for short-term survival in Drosophila nevertheless also caused significant reductions in life span for the flies. Thus, although both repeated and chronic stress can be tolerated, they may result in a shorter life. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of weightlessness on human fluid and electrolyte physiology

NASA Technical Reports Server (NTRS)

Leach, Carolyn S.; Johnson, Philip C., Jr.

1991-01-01

Skylab and Spacelab data on changes occurring in human fluid and electrolyte physiology during the acute and adaptive phases of adaptation to spaceflight are summarized. The combined results for all three Spacelab studies show that hyponatremia developed within 20 h after the onset of weightlessness and continued throughout the flights, and hypokalemia developed by 40 h. Antidiuretic hormone was increased in plasma throughout the flights. Aldosterone decreased by 40 h, but after 7 days it had reached preflight levels.

Limitations to Thermoregulation and Acclimatization Challenge Human Adaptation to Global Warming.

PubMed

Hanna, Elizabeth G; Tait, Peter W

2015-07-15

Human thermoregulation and acclimatization are core components of the human coping mechanism for withstanding variations in environmental heat exposure. Amidst growing recognition that curtailing global warming to less than two degrees is becoming increasing improbable, human survival will require increasing reliance on these mechanisms. The projected several fold increase in extreme heat events suggests we need to recalibrate health protection policies and ratchet up adaptation efforts. Climate researchers, epidemiologists, and policy makers engaged in climate change adaptation and health protection are not commonly drawn from heat physiology backgrounds. Injecting a scholarly consideration of physiological limitations to human heat tolerance into the adaptation and policy literature allows for a broader understanding of heat health risks to support effective human adaptation and adaptation planning. This paper details the physiological and external environmental factors that determine human thermoregulation and acclimatization. We present a model to illustrate the interrelationship between elements that modulate the physiological process of thermoregulation. Limitations inherent in these processes, and the constraints imposed by differing exposure levels, and thermal comfort seeking on achieving acclimatization, are then described. Combined, these limitations will restrict the likely contribution that acclimatization can play in future human adaptation to global warming. We postulate that behavioral and technological adaptations will need to become the dominant means for human individual and societal adaptations as global warming progresses.

Acid adaptation of Lactobacillus delbrueckii subsp. bulgaricus induces physiological responses at membrane and cytosolic levels that improves cryotolerance.

PubMed

Streit, F; Delettre, J; Corrieu, G; Béal, C

2008-10-01

This work aimed at clarifying the physiological responses of Lactobacillus delbrueckii subsp. bulgaricus CFL1 cells after exposure to acidification at the end of fermentation, in relation to their cryotolerance. Cells acidified at the end of the fermentation (pH 5.25 for 30 min) had their cryotolerance improved as compared to the reference condition (pH 6.0). By analyzing the cytosolic proteome, it was established that changes occurred in the synthesis of 21 proteins, involved in energy metabolism, nucleotide and protein synthesis and stress response. Acidification also induced a slight decrease in unsaturated to saturated and cyclic to saturated membrane fatty acid ratios. Lactobacillus bulgaricus CFL1 was able to develop a combined physiological response at both membrane and cytosolic levels. This acid adaptation was referred as a cross-protection phenomenon as it allowed the cells to become more tolerant to cold stress. This study increased knowledge concerning the physiological mechanisms that explained the cross-protection by acid adaptation. It may be useful for improving cryotolerance of lactic acid bacteria, either in cells banks or in an industrial context.

Gene expression changes in the coccolithophore Emiliania huxleyi after 500 generations of selection to ocean acidification.

PubMed

Lohbeck, Kai T; Riebesell, Ulf; Reusch, Thorsten B H

2014-07-07

Coccolithophores are unicellular marine algae that produce biogenic calcite scales and substantially contribute to marine primary production and carbon export to the deep ocean. Ongoing ocean acidification particularly impairs calcifying organisms, mostly resulting in decreased growth and calcification. Recent studies revealed that the immediate physiological response in the coccolithophore Emiliania huxleyi to ocean acidification may be partially compensated by evolutionary adaptation, yet the underlying molecular mechanisms are currently unknown. Here, we report on the expression levels of 10 candidate genes putatively relevant to pH regulation, carbon transport, calcification and photosynthesis in E. huxleyi populations short-term exposed to ocean acidification conditions after acclimation (physiological response) and after 500 generations of high CO2 adaptation (adaptive response). The physiological response revealed downregulation of candidate genes, well reflecting the concomitant decrease of growth and calcification. In the adaptive response, putative pH regulation and carbon transport genes were up-regulated, matching partial restoration of growth and calcification in high CO2-adapted populations. Adaptation to ocean acidification in E. huxleyi likely involved improved cellular pH regulation, presumably indirectly affecting calcification. Adaptive evolution may thus have the potential to partially restore cellular pH regulatory capacity and thereby mitigate adverse effects of ocean acidification. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Predictions of the Contribution of HCN Half-Maximal Activation Potential Heterogeneity to Variability in Intrinsic Adaptation of Spiral Ganglion Neurons.

PubMed

Boulet, Jason; Bruce, Ian C

2017-04-01

Spiral ganglion neurons (SGNs) exhibit a wide range in their strength of intrinsic adaptation on a timescale of 10s to 100s of milliseconds in response to electrical stimulation from a cochlear implant (CI). The purpose of this study was to determine how much of that variability could be caused by the heterogeneity in half-maximal activation potentials of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels, which are known to produce intrinsic adaptation. In this study, a computational membrane model of cat type I SGN was developed based on the Hodgkin-Huxley model plus HCN and low-threshold potassium (KLT) conductances in which the half-maximal activation potential of the HCN channel was varied and the response of the SGN to pulse train and paired-pulse stimulation was simulated. Physiologically plausible variation of HCN half-maximal activation potentials could indeed determine the range of adaptation on the timescale of 10s to 100s of milliseconds and recovery from adaptation seen in the physiological data while maintaining refractoriness within physiological bounds. This computational model demonstrates that HCN channels may play an important role in regulating the degree of adaptation in response to pulse train stimulation and therefore contribute to variable constraints on acoustic information coding by CIs. This finding has broad implications for CI stimulation paradigms in that cell-to-cell variation of HCN channel properties are likely to significantly alter SGN excitability and therefore auditory perception.

Patterns of host adaptation in Frankliniella occidentalis among vegetable crops

USDA-ARS?s Scientific Manuscript database

The current study examined the variation in life table characteristics, and physiological, biochemical, and molecular bases of western flower thrips, Frankliniella occidentalis (Pergande) host adaptation patterns. The main objective was to determine whether host availability affects insect preferenc...

Trichinella spiralis: the evolution of adaptation and parasitism

USDA-ARS?s Scientific Manuscript database

Parasitism among nematodes has occurred in multiple, independent events. Deciphering processes that drive species diversity and adaptation are keys to understanding parasitism and advancing control strategies. Studies have been put forth on morphological and physiological aspects of parasitism and a...

Functional genomics of physiological plasticity and local adaptation in killifish.

PubMed

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

2011-01-01

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

Functional Genomics of Physiological Plasticity and Local Adaptation in Killifish

PubMed Central

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

2011-01-01

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

Asynchronous evolution of physiology and morphology in Anolis lizards.

PubMed

Hertz, Paul E; Arima, Yuzo; Harrison, Alexis; Huey, Raymond B; Losos, Jonathan B; Glor, Richard E

2013-07-01

Species-rich adaptive radiations typically diversify along several distinct ecological axes, each characterized by morphological, physiological, and behavioral adaptations. We test here whether different types of adaptive traits share similar patterns of evolution within a radiation by investigating patterns of evolution of morphological traits associated with microhabitat specialization and of physiological traits associated with thermal biology in Anolis lizards. Previous studies of anoles suggest that close relatives share the same "structural niche" (i.e., use the same types of perches) and are similar in body size and shape, but live in different "climatic niches" (i.e., use habitats with different insolation and temperature profiles). Because morphology is closely tied to structural niche and field active body temperatures are tied to climatic niches in Anolis, we expected phylogenetic analyses to show that morphology is more evolutionarily conservative than thermal physiology. In support of this hypothesis, we find (1) that thermal biology exhibits more divergence among recently diverged Anolis taxa than does morphology; and (2) diversification of thermal biology among all species often follows diversification in morphology. These conclusions are remarkably consistent with predictions made by anole biologists in the 1960s and 1970s. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Physiologic adaptation to space - Space adaptation syndrome

NASA Technical Reports Server (NTRS)

Vanderploeg, J. M.

1985-01-01

The adaptive changes of the neurovestibular system to microgravity, which result in space motion sickness (SMS), are studied. A list of symptoms, which range from vomiting to drowsiness, is provided. The two patterns of symptom development, rapid and gradual, and the duration of the symptoms are described. The concept of sensory conflict and rearrangements to explain SMS is being investigated.

Physiological Responses in a Variable Environment: Relationships between Metabolism, Hsp and Thermotolerance in an Intertidal-Subtidal Species

PubMed Central

Wang, Qing-lin; Dong, Shuang-lin

2011-01-01

Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky–eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins) and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps) occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT). The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment. PMID:22022615

Limitations to Thermoregulation and Acclimatization Challenge Human Adaptation to Global Warming

PubMed Central

Hanna, Elizabeth G.; Tait, Peter W.

2015-01-01

Human thermoregulation and acclimatization are core components of the human coping mechanism for withstanding variations in environmental heat exposure. Amidst growing recognition that curtailing global warming to less than two degrees is becoming increasing improbable, human survival will require increasing reliance on these mechanisms. The projected several fold increase in extreme heat events suggests we need to recalibrate health protection policies and ratchet up adaptation efforts. Climate researchers, epidemiologists, and policy makers engaged in climate change adaptation and health protection are not commonly drawn from heat physiology backgrounds. Injecting a scholarly consideration of physiological limitations to human heat tolerance into the adaptation and policy literature allows for a broader understanding of heat health risks to support effective human adaptation and adaptation planning. This paper details the physiological and external environmental factors that determine human thermoregulation and acclimatization. We present a model to illustrate the interrelationship between elements that modulate the physiological process of thermoregulation. Limitations inherent in these processes, and the constraints imposed by differing exposure levels, and thermal comfort seeking on achieving acclimatization, are then described. Combined, these limitations will restrict the likely contribution that acclimatization can play in future human adaptation to global warming. We postulate that behavioral and technological adaptations will need to become the dominant means for human individual and societal adaptations as global warming progresses. PMID:26184272

Plasticity and local adaptation explain lizard cold tolerance.

PubMed

Card, Daren C; Schield, Drew R; Castoe, Todd A

2018-05-01

How does climate variation limit the range of species and what does it take for species to colonize new regions? In this issue of Molecular Ecology, Campbell-Staton et al. () address these broad questions by investigating cold tolerance adaptation in the green anole lizard (Anolis carolinensis) across a latitudinal transect. By integrating physiological data, gene expression data and acclimation experiments, the authors disentangle the mechanisms underlying cold adaptation. They first establish that cold tolerance adaptation in Anolis lizards follows the predictions of the oxygen- and capacity-limited thermal tolerance hypothesis, which states that organisms are limited by temperature thresholds at which oxygen supply cannot meet demand. They then explore the drivers of cold tolerance at a finer scale, finding evidence that northern populations are adapted to cooler thermal regimes and that both phenotypic plasticity and heritable genetic variation contribute to cold tolerance. The integration of physiological and gene expression data further highlights the varied mechanisms that drive cold tolerance adaptation in Anolis lizards, including both supply-side and demand-side adaptations that improve oxygen economy. Altogether, their work provides new insight into the physiological and genetic mechanisms underlying adaptation to new climatic niches and demonstrates that cold tolerance in northern lizard populations is achieved through the synergy of physiological plasticity and local genetic adaptation for thermal performance. © 2018 John Wiley & Sons Ltd.

Planning a sports training program using Adaptive Particle Swarm Optimization with emphasis on physiological constraints.

PubMed

Kumyaito, Nattapon; Yupapin, Preecha; Tamee, Kreangsak

2018-01-08

An effective training plan is an important factor in sports training to enhance athletic performance. A poorly considered training plan may result in injury to the athlete, and overtraining. Good training plans normally require expert input, which may have a cost too great for many athletes, particularly amateur athletes. The objectives of this research were to create a practical cycling training plan that substantially improves athletic performance while satisfying essential physiological constraints. Adaptive Particle Swarm Optimization using ɛ-constraint methods were used to formulate such a plan and simulate the likely performance outcomes. The physiological constraints considered in this study were monotony, chronic training load ramp rate and daily training impulse. A comparison of results from our simulations against a training plan from British Cycling, which we used as our standard, showed that our training plan outperformed the benchmark in terms of both athletic performance and satisfying all physiological constraints.

PLANT CULTURAL SYSTEM FOR MONITORING EVAPOTRANSPIRATION AND PHYSIOLOGICAL RESPONSES UNDER FIELD CONDITIONS

EPA Science Inventory

A plant culture system incorporating the water-table root-screen method for controlling plant water status was adapted for use in open-top field exposure chambers for studying the effects of drought stress on physiological responses. The daily transpiration rates of the plants we...

Enhancing the effectiveness of human-robot teaming with a closed-loop system.

PubMed

Teo, Grace; Reinerman-Jones, Lauren; Matthews, Gerald; Szalma, James; Jentsch, Florian; Hancock, Peter

2018-02-01

With technological developments in robotics and their increasing deployment, human-robot teams are set to be a mainstay in the future. To develop robots that possess teaming capabilities, such as being able to communicate implicitly, the present study implemented a closed-loop system. This system enabled the robot to provide adaptive aid without the need for explicit commands from the human teammate, through the use of multiple physiological workload measures. Such measures of workload vary in sensitivity and there is large inter-individual variability in physiological responses to imposed taskload. Workload models enacted via closed-loop system should accommodate such individual variability. The present research investigated the effects of the adaptive robot aid vs. imposed aid on performance and workload. Results showed that adaptive robot aid driven by an individualized workload model for physiological response resulted in greater improvements in performance compared to aid that was simply imposed by the system. Copyright © 2017 Elsevier Ltd. All rights reserved.

The physiological ecology of the supratidal amphipod Talorchestia longicornis.

PubMed

Ramus, Aaron P; Forward, Richard B

2012-02-01

Physiology, behavior, habitat, and morphology are used to determine the degree of adaptation to life on land for amphipod species and systemization within the four functional groups of the family talitridae. Talorchestia longicornis is a semi-terrestrial amphipod found in the supratidal zone of estuaries. The present study investigates the physiological adaptations of this species to life on land through measurements of osmoregulation and respiration. Over the salinity range of 1-40‰, T. longicornis regulated its hemolymph hyperosmotically at low salinities and hypoosmotically at high salinities. The isosmotic point was about 27‰. Analogously, hemolymph chloride levels were well regulated being hyperionic at low salinities and hypoionic at high salinities. This species is capable of respiration in both air and water. Slopes (b values) of the relationship between weight and oxygen uptake rates ranged from 0.316 to 0.590. Oxygen uptake rates were higher in air than water and at night versus day. Q(10) values were slightly below 2.0 for respiration in air for amphipods, irrespective of weight. These physiological adaptations, along with its behaviors, habitat, and morphology, place T. longicornis within the Group III sandhoppers of the Talitridae. Copyright © 2011. Published by Elsevier Inc.

Eating chemically defended prey: alkaloid metabolism in an invasive ladybird predator of other ladybirds (Coleoptera: Coccinellidae).

PubMed

Sloggett, J J; Davis, A J

2010-01-15

By comparison with studies of herbivore physiological adaptation to plant allelochemicals, work on predator physiological adaptation to potentially toxic prey has been very limited. Such studies are important in understanding how evolution could shape predator diets. An interesting question is the specificity of predator adaptation to prey allelochemicals, given that many predators consume diverse prey with different chemical defences. The ladybird Harmonia axyridis, an invasive species in America, Europe and Africa, is considered a significant predatory threat to native invertebrates, particularly other aphid-eating ladybirds of which it is a strong intraguild predator. Although ladybirds possess species-specific alkaloid defences, H. axyridis exhibits high tolerance for allospecific ladybird prey alkaloids. Nonetheless, it performs poorly on species with novel alkaloids not commonly occurring within its natural range. We examined alkaloid fate in H. axyridis larvae after consumption of two other ladybird species, one containing an alkaloid historically occurring within the predator's native range (isopropyleine) and one containing a novel alkaloid that does not (adaline). Our results indicate that H. axyridis rapidly chemically modifies the alkaloid to which it has been historically exposed to render it less harmful: this probably occurs outside of the gut. The novel, more toxic alkaloid persists in the body unchanged for longer. Our results suggest metabolic alkaloid specialisation, in spite of the diversity of chemically defended prey that the predator consumes. Physiological adaptations appear to have made H. axyridis a successful predator of other ladybirds; however, limitations are imposed by its physiology when it eats prey with novel alkaloids.

Nutrition and human physiological adaptations to space flight

NASA Technical Reports Server (NTRS)

Lane, H. W.; LeBlanc, A. D.; Putcha, L.; Whitson, P. A.

1993-01-01

Space flight provides a model for the study of healthy individuals undergoing unique stresses. This review focuses on how physiological adaptations to weightlessness may affect nutrient and food requirements in space. These adaptations include reductions in body water and plasma volume, which affect the renal and cardiovascular systems and thereby fluid and electrolyte requirements. Changes in muscle mass and function may affect requirements for energy, protein and amino acids. Changes in bone mass lead to increased urinary calcium concentrations, which may increase the risk of forming renal stones. Space motion sickness may influence putative changes in gastro-intestinal-hepatic function; neurosensory alterations may affect smell and taste. Some or all of these effects may be ameliorated through the use of specially designed dietary countermeasures.

Imaging light responses of foveal ganglion cells in the living macaque eye.

PubMed

Yin, Lu; Masella, Benjamin; Dalkara, Deniz; Zhang, Jie; Flannery, John G; Schaffer, David V; Williams, David R; Merigan, William H

2014-05-07

The fovea dominates primate vision, and its anatomy and perceptual abilities are well studied, but its physiology has been little explored because of limitations of current physiological methods. In this study, we adapted a novel in vivo imaging method, originally developed in mouse retina, to explore foveal physiology in the macaque, which permits the repeated imaging of the functional response of many retinal ganglion cells (RGCs) simultaneously. A genetically encoded calcium indicator, G-CaMP5, was inserted into foveal RGCs, followed by calcium imaging of the displacement of foveal RGCs from their receptive fields, and their intensity-response functions. The spatial offset of foveal RGCs from their cone inputs makes this method especially appropriate for fovea by permitting imaging of RGC responses without excessive light adaptation of cones. This new method will permit the tracking of visual development, progression of retinal disease, or therapeutic interventions, such as insertion of visual prostheses.

Trade-offs in thermal adaptation: the need for a molecular to ecological integration.

PubMed

Pörtner, Hans O; Bennett, Albert F; Bozinovic, Francisco; Clarke, Andrew; Lardies, Marco A; Lucassen, Magnus; Pelster, Bernd; Schiemer, Fritz; Stillman, Jonathon H

2006-01-01

Through functional analyses, integrative physiology is able to link molecular biology with ecology as well as evolutionary biology and is thereby expected to provide access to the evolution of molecular, cellular, and organismic functions; the genetic basis of adaptability; and the shaping of ecological patterns. This paper compiles several exemplary studies of thermal physiology and ecology, carried out at various levels of biological organization from single genes (proteins) to ecosystems. In each of those examples, trade-offs and constraints in thermal adaptation are addressed; these trade-offs and constraints may limit species' distribution and define their level of fitness. For a more comprehensive understanding, the paper sets out to elaborate the functional and conceptual connections among these independent studies and the various organizational levels addressed. This effort illustrates the need for an overarching concept of thermal adaptation that encompasses molecular, organellar, cellular, and whole-organism information as well as the mechanistic links between fitness, ecological success, and organismal physiology. For this data, the hypothesis of oxygen- and capacity-limited thermal tolerance in animals provides such a conceptual framework and allows interpreting the mechanisms of thermal limitation of animals as relevant at the ecological level. While, ideally, evolutionary studies over multiple generations, illustrated by an example study in bacteria, are necessary to test the validity of such complex concepts and underlying hypotheses, animal physiology frequently is constrained to functional studies within one generation. Comparisons of populations in a latitudinal cline, closely related species from different climates, and ontogenetic stages from riverine clines illustrate how evolutionary information can still be gained. An understanding of temperature-dependent shifts in energy turnover, associated with adjustments in aerobic scope and performance, will result. This understanding builds on a mechanistic analysis of the width and location of thermal windows on the temperature scale and also on study of the functional properties of relevant proteins and associated gene expression mechanisms.

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…

Academic Performance in Human Anatomy and Physiology Classes: A 2-Yr Study of Academic Motivation and Grade Expectation

ERIC Educational Resources Information Center

Sturges, Diana; Maurer, Trent W.; Allen, Deborah; Gatch, Delena Bell; Shankar, Padmini

2016-01-01

This project used a nonexperimental design with a convenience sample and studied the relationship between academic motivation, grade expectation, and academic performance in 1,210 students enrolled in undergraduate human anatomy and physiology (HAP) classes over a 2-yr period. A 42-item survey that included 28 items of the adapted academic…

Match and mismatch: conservation physiology, nutritional ecology and the timescales of biological adaptation

PubMed Central

Raubenheimer, David; Simpson, Stephen J.; Tait, Alice H.

2012-01-01

Conservation physiology (CP) and nutritional ecology (NE) are both integrative sciences that share the fundamental aim of understanding the patterns, mechanisms and consequences of animal responses to changing environments. Here, we explore the high-level similarities and differences between CP and NE, identifying as central themes to both fields the multiple timescales over which animals adapt (and fail to adapt) to their environments, and the need for integrative models to study these processes. At one extreme are the short-term regulatory responses that modulate the state of animals in relation to the environment, which are variously considered under the concepts of homeostasis, homeorhesis, enantiostasis, heterostasis and allostasis. In the longer term are developmental responses, including phenotypic plasticity and transgenerational effects mediated by non-genomic influences such as parental physiology, epigenetic effects and cultural learning. Over a longer timescale still are the cumulative genetic changes that take place in Darwinian evolution. We present examples showing how the adaptive responses of animals across these timescales have been represented in an integrative framework from NE, the geometric framework (GF) for nutrition, and close with an illustration of how GF can be applied to the central issue in CP, animal conservation. PMID:22566672

Match and mismatch: conservation physiology, nutritional ecology and the timescales of biological adaptation.

PubMed

Raubenheimer, David; Simpson, Stephen J; Tait, Alice H

2012-06-19

Conservation physiology (CP) and nutritional ecology (NE) are both integrative sciences that share the fundamental aim of understanding the patterns, mechanisms and consequences of animal responses to changing environments. Here, we explore the high-level similarities and differences between CP and NE, identifying as central themes to both fields the multiple timescales over which animals adapt (and fail to adapt) to their environments, and the need for integrative models to study these processes. At one extreme are the short-term regulatory responses that modulate the state of animals in relation to the environment, which are variously considered under the concepts of homeostasis, homeorhesis, enantiostasis, heterostasis and allostasis. In the longer term are developmental responses, including phenotypic plasticity and transgenerational effects mediated by non-genomic influences such as parental physiology, epigenetic effects and cultural learning. Over a longer timescale still are the cumulative genetic changes that take place in Darwinian evolution. We present examples showing how the adaptive responses of animals across these timescales have been represented in an integrative framework from NE, the geometric framework (GF) for nutrition, and close with an illustration of how GF can be applied to the central issue in CP, animal conservation.

Evolution of adaptation mechanisms: Adaptation energy, stress, and oscillating death.

PubMed

Gorban, Alexander N; Tyukina, Tatiana A; Smirnova, Elena V; Pokidysheva, Lyudmila I

2016-09-21

In 1938, Selye proposed the notion of adaptation energy and published 'Experimental evidence supporting the conception of adaptation energy.' Adaptation of an animal to different factors appears as the spending of one resource. Adaptation energy is a hypothetical extensive quantity spent for adaptation. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. The controversial points of view impede the systematic use of the notion of adaptation energy despite experimental evidence. Nevertheless, the response to many harmful factors often has general non-specific form and we suggest that the mechanisms of physiological adaptation admit a very general and nonspecific description. We aim to demonstrate that Selye׳s adaptation energy is the cornerstone of the top-down approach to modelling of non-specific adaptation processes. We analyze Selye׳s axioms of adaptation energy together with Goldstone׳s modifications and propose a series of models for interpretation of these axioms. Adaptation energy is considered as an internal coordinate on the 'dominant path' in the model of adaptation. The phenomena of 'oscillating death' and 'oscillating remission' are predicted on the base of the dynamical models of adaptation. Natural selection plays a key role in the evolution of mechanisms of physiological adaptation. We use the fitness optimization approach to study of the distribution of resources for neutralization of harmful factors, during adaptation to a multifactor environment, and analyze the optimal strategies for different systems of factors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Treatment Education Based on the Roy Adaptation Model on Adjustment of Hemodialysis Patients.

PubMed

Kacaroglu Vicdan, Ayse; Gulseven Karabacak, Bilgi

2016-01-01

The Roy Adaptation Model examines the individual in 4 fields: physiological mode, self-concept mode, role function mode, and interdependence mode. Hemodialysis treatment is associated with the Roy Adaptation Model as it involves fields that might be needed by the individual with chronic renal disease. This research was conducted as randomized controlled experiment with the aim of determining the effect of the education given in accordance with the Roy Adaptation Model on physiological, psychological, and social adaptation of individuals undergoing hemodialysis treatment. This was a random controlled experimental study. The study was conducted at a dialysis center in Konya-Aksehir in Turkey between July 1 and December 31, 2012. The sample was composed of 82 individuals-41 experimental and 41 control. In the second interview, there was a decrease in the systolic blood pressures and body weights of the experimental group, an increase in the scores of functional performance and self-respect, and a decrease in the scores of psychosocial adaptation. In the control group, on the other hand, there was a decrease in the scores of self-respect and an increase in the scores of psychosocial adaptation. The 2 groups were compared in terms of adaptation variables and a difference was determined on behalf of the experimental group. The training that was provided and evaluated for individuals receiving hemodialysis according to 4 modes of the Roy Adaptation Model increased physical, psychological, and social adaptation.

Urban plant physiology: adaptation-mitigation strategies under permanent stress.

PubMed

Calfapietra, Carlo; Peñuelas, Josep; Niinemets, Ülo

2015-02-01

Urban environments that are stressful for plant function and growth will become increasingly widespread in future. In this opinion article, we define the concept of 'urban plant physiology', which focuses on plant responses and long term adaptations to urban conditions and on the capacity of urban vegetation to mitigate environmental hazards in urbanized settings such as air and soil pollution. Use of appropriate control treatments would allow for studies in urban environments to be comparable to expensive manipulative experiments. In this opinion article, we propose to couple two approaches, based either on environmental gradients or manipulated gradients, to develop the concept of urban plant physiology for assessing how single or multiple environmental factors affect the key environmental services provided by urban forests. Copyright © 2014 Elsevier Ltd. All rights reserved.

Short-term heat acclimation prior to a multi-day desert ultra-marathon improves physiological and psychological responses without compromising immune status.

PubMed

Willmott, Ashley G B; Hayes, Mark; Waldock, Kirsty A M; Relf, Rebecca L; Watkins, Emily R; James, Carl A; Gibson, Oliver R; Smeeton, Nicholas J; Richardson, Alan J; Watt, Peter W; Maxwell, Neil S

2017-11-01

Multistage, ultra-endurance events in hot, humid conditions necessitate thermal adaptation, often achieved through short term heat acclimation (STHA), to improve performance by reducing thermoregulatory strain and perceptions of heat stress. This study investigated the physiological, perceptual and immunological responses to STHA prior to the Marathon des Sables. Eight athletes (age 42 ± 4 years and body mass 81.9 ± 15.0 kg) completed 4 days of controlled hyperthermia STHA (60 min·day ‒1 , 45°C and 30% relative humidity). Pre, during and post sessions, physiological and perceptual measures were recorded. Immunological measures were recorded pre-post sessions 1 and 4. STHA improved thermal comfort (P = 0.02), sensation (P = 0.03) and perceived exertion (P = 0.04). A dissociated relationship between perceptual fatigue and T re was evident after STHA, with reductions in perceived Physical (P = 0.04) and General (P = 0.04) fatigue. Exercising T re and HR did not change (P > 0.05) however, sweat rate increased 14% (P = 0.02). No changes were found in white blood cell counts or content (P > 0.05). Four days of STHA facilitates effective perceptual adaptations, without compromising immune status prior to an ultra-endurance race in heat stress. A greater physiological strain is required to confer optimal physiological adaptations.

Co-Adaptive Aiding and Automation Enhance Operator Performance

DTIC Science & Technology

2013-03-01

activation system. There is a close relation between physiologically activated adaptive aiding and brain- computer interfaces ( BCI ). BCI here refers...classification of EEG signals (Farwell & Donchin, 1988). Physiologically activated adaptive aiding is, in a sense, a special case of BCI wherein the...as passive BCI , e.g. Zander, Kothe, Jatzev, & 3 Distribution A: Approved for public release; distribution unlimited. 88 ABW Cleared 05/13/2013

Intestinal mucosal atrophy and adaptation

PubMed Central

Shaw, Darcy; Gohil, Kartik; Basson, Marc D

2012-01-01

Mucosal adaptation is an essential process in gut homeostasis. The intestinal mucosa adapts to a range of pathological conditions including starvation, short-gut syndrome, obesity, and bariatric surgery. Broadly, these adaptive functions can be grouped into proliferation and differentiation. These are influenced by diverse interactions with hormonal, immune, dietary, nervous, and mechanical stimuli. It seems likely that clinical outcomes can be improved by manipulating the physiology of adaptation. This review will summarize current understanding of the basic science surrounding adaptation, delineate the wide range of potential targets for therapeutic intervention, and discuss how these might be incorporated into an overall treatment plan. Deeper insight into the physiologic basis of adaptation will identify further targets for intervention to improve clinical outcomes. PMID:23197881

Adaptive Calibration of Children's Physiological Responses to Family Stress: The Utility of Evolutionary Developmental Theory--Comment on Del Giudice et al. (2012) and Sturge-Apple et al. (2012)

ERIC Educational Resources Information Center

Bugental, Daphne Blunt

2012-01-01

Children's physiological reactions to stress are presented from the broader theoretical perspective of adaptive calibration to the environment, as rooted in life history theory. Del Giudice, Hinnant, Ellis, and El-Sheikh (2012) focus on children's physiological responses to a stressful task as a consequence of their history of family stress.…

Biochemical and physiological adaptations in the estuarine crab Neohelice granulata during salinity acclimation.

PubMed

Bianchini, Adalto; Lauer, Mariana Machado; Nery, Luiz Eduardo Maia; Colares, Elton Pinto; Monserrat, José María; Dos Santos Filho, Euclydes Antônio

2008-11-01

Neohelice granulata (Chasmagnathus granulatus) is an intertidal crab species living in salt marshes from estuaries and lagoons along the Atlantic coast of South America. It is a key species in these environments because it is responsible for energy transfer from producers to consumers. In order to deal with the extremely marked environmental salinity changes occurring in salt marshes, N. granulata shows important and interesting structural, biochemical, and physiological adaptations at the gills level. These adaptations characterize this crab as a euryhaline species, tolerating environmental salinities ranging from very diluted media to concentrated seawater. These characteristics had led to its use as an animal model to study estuarine adaptations in crustaceans. Therefore, the present review focuses on the influence of environmental salinity on N. granulata responses at the ecological, organismic and molecular levels. Aspects covered include salinity tolerance, osmo- and ionoregulatory patterns, morphological and structural adaptations at the gills, and mechanisms of ion transport and their regulation at the gills level during environmental salinity acclimation. Finally, this review compiles information on the effects of some environmental pollutants on iono- and osmoregulatory adaptations showed by N. granulata.

Natural selection on plant physiological traits in an urban environment

NASA Astrophysics Data System (ADS)

Lambrecht, Susan C.; Mahieu, Stephanie; Cheptou, Pierre-Olivier

2016-11-01

Current rates of urbanization are creating new opportunities for studying urban plant ecology, but our knowledge of urban plant physiology lags behind that of other ecosystems. Moreover, higher temperatures, elevated CO2, and increased inorganic nitrogen deposition along with altered moisture regimes of urban as compared to rural areas creates a compelling analog for studying adaptations of plants to climate change. We grew plants under common conditions in a greenhouse to determine whether populations of Crepis sancta (Asteraceae) differed in phenological, morphological, and physiological traits. We also used a field experiment to test for natural selection on these traits in urban Montpellier, France. Urban plants flowered and senesced later than rural plants, and natural selection favored later phenology in the urban habitat. Natural selection also favored larger plants with more leaves, and increased photosynthesis and leaf nitrogen concentration. Ours is the first study to document selection on plant functional traits in an urban habitat and, as such, advances our understanding of urban plant ecology and possible adaptations to climate change.

Where science meets practice: Olympic coaches' crafting of the tapering process.

PubMed

Ritchie, Darren; Allen, Justine B; Kirkland, Andrew

2018-05-01

Although there is research providing physiologically-based guidance for the content of the taper, this study was the first to examine how coaches actually implement the taper. The purpose of this study was to examine the taper planning and implementation processes of successful Olympic coaches leading up to major competitions and how they learned about tapering. Seven track and field coaches participated in semi-structured interviews exploring their tapering processes. To be considered for inclusion, coaches were required to have coached one or more athletes to an Olympic or Paralympic medal. Through a process of axial and open coding interview transcripts were analysed and lower and higher order themes developed describing the coaches' tapering processes. Our findings indicate that the strategies employed to achieve the desired physiological adaptions of the taper were consistent with research (e.g., reduction in volume whilst maintaining intensity and frequency). However, our findings also suggest that tapering is far from a straight forward "textbook" process. The taper was not restricted to physiological outcomes with coaches considering athletes' psychological as well as physical state. Coaches also involved the athlete in the process, adapted the taper to the athlete, continually monitored its progress, and adapted it further as required.

Regulated endocytosis of opioid receptors: cellular mechanisms and proposed roles in physiological adaptation to opiate drugs.

PubMed

von Zastrow, Mark; Svingos, Adena; Haberstock-Debic, Helena; Evans, Chris

2003-06-01

Opiate drugs such as morphine and heroin are among the most effective analgesics known. Prolonged or repeated administration of opiates produces adaptive changes in the nervous system that lead to reduced drug potency or efficacy (tolerance), as well as physiological withdrawal symptoms and behavioral manifestations such as craving when drug use is terminated (dependence). These adaptations limit the therapeutic utility of opiate drugs, particularly in the treatment of chronically painful conditions, and are thought to contribute to the highly addictive nature of opiates. For many years it has been proposed that physiological tolerance to opiate drugs is associated with a modification of the number or functional activity of opioid receptors in specific neurons. We now understand certain mechanisms of opioid receptor desensitization and endocytosis in considerable detail. However, the functional roles that these mechanisms play in the complex physiological adaptation of the intact nervous system to opiates are only beginning to be explored.

Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports.

PubMed

Périard, J D; Racinais, S; Sawka, M N

2015-06-01

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm-hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Syndecan-4 Signaling Is Required for Exercise-Induced Cardiac Hypertrophy

PubMed Central

Xie, Jun; He, Guixin; Chen, Qinhua; Sun, Jiayin; Dai, Qin; Lu, Jianrong; Li, Guannan; Wu, Han; Li, Ran; Chen, Jianzhou; Xu, Wei; Xu, Biao

2016-01-01

Cardiac hypertrophy can be broadly classified as either physiological or pathological. Physiological stimuli such as exercise cause adaptive cardiac hypertrophy and normal heart function. Pathological stimuli including hypertension and aortic valvular stenosis cause maladaptive cardiac remodeling and ultimately heart failure. Syndecan-4 (synd4) is a transmembrane proteoglycan identified as being involved in cardiac adaptation after injury, but whether it takes part in physiological cardiac hypertrophy is unclear. We observed upregulation of synd4 in exercise-induced hypertrophic myocardium. To evaluate the role of synd4 in the physiological form of cardiac hypertrophy, mice lacking synd4 (synd4–/–) were exercised by swimming for 4 wks. Ultrasonic cardiogram (UCG) and histological analysis revealed that swimming induced the hypertrophic phenotype but was blunted in synd4–/– compared with wild-type (WT) mice. The swimming-induced activation of Akt, a key molecule in physiological hypertrophy was also more decreased than in WT controls. In cultured cardiomyocytes, synd4 overexpression could induce cell enlargement, protein synthesis and distinct physiological molecular alternation. Akt activation also was observed in synd4-overexpressed cardiomyocytes. Furthermore, inhibition of protein kinase C (PKC) prevented the synd4-induced hypertrophic phenotype and Akt phosphorylation. This study identified an essential role of synd4 in mediation of physiological cardiac hypertrophy. PMID:26835698

Human adaptation to isolated and confined environments: Preliminary findings of a seven month Antarctic winter-over human factors study

NASA Technical Reports Server (NTRS)

Evans, Gary W.; Stokols, Daniel; Carrere, Sybil

1988-01-01

This field study was conducted during the last decade of an austral winter-over at Palmer Station in the Antarctic. The purpose of the study was to understand temporal patterns in physiological arousal and psychological mood over the course of the mission. The investigators were principally interested in how people adapted over time to chronic and acute stressors, and how people use and modify their built environment. Physiological and psychological data were collected several times a week, and information on behavior and the use of physical facilities was collected monthly. Physiological and psychological data were compared with social changes in the setting toward the development of a sequential model of human-environment transactional relationships. Based on the study results, guidelines for design of future isolated and confined environments (ICEs) included: plan space for items which make people feel at home, provide materials to allow people to personalize their environment, allow for flexible environments, provide areas for visual and auditory privacy, equip areas for socializing and remove them from private areas, and provide facilities for exercise and for projects involving physical activity. The study offers guidelines about patterns of adaption that could be expected in an ICE, discusses how these settings can be programmed to facilitate successful adjustment, and provides information about how to design future ICE habitats to maximize a healthy living environment.

Three-Dimensional Normal Human Neutral Progenitor Tissue-Like Assemblies: A Model for Persistent Varicella-Zoster Virus Infection and Platform to Study Oxidate Stress and Damage in Multiple Hit Scenarios

NASA Technical Reports Server (NTRS)

Goodwin, Thomas J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

2014-01-01

The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpes virus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex three-dimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6]. By combining the RFs of microgravity, radiation, and viral infection we will demonstrate that living in the space environment leads to significant physiological consequences for the peripheral and subsequently the central nervous system (PNS, CNS) associated with OSaD generation and consequentially endangers long-duration and exploration-class missions.

Ecological comparison of cellular stress responses among populations - normalizing RT-qPCR values to investigate differential environmental adaptations.

PubMed

Koenigstein, Stefan; Pöhlmann, Kevin; Held, Christoph; Abele, Doris

2013-05-16

Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species' response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions.

Ecological comparison of cellular stress responses among populations – normalizing RT-qPCR values to investigate differential environmental adaptations

PubMed Central

2013-01-01

Background Rising temperatures and other environmental factors influenced by global climate change can cause increased physiological stress for many species and lead to range shifts or regional population extinctions. To advance the understanding of species’ response to change and establish links between individual and ecosystem adaptations, physiological reactions have to be compared between populations living in different environments. Although changes in expression of stress genes are relatively easy to quantify, methods for reliable comparison of the data remain a contentious issue. Using normalization algorithms and further methodological considerations, we compare cellular stress response gene expression levels measured by RT-qPCR after air exposure experiments among different subpopulations of three species of the intertidal limpet Nacella. Results Reference gene assessment algorithms reveal that stable reference genes can differ among investigated populations and / or treatment groups. Normalized expression values point to differential defense strategies to air exposure in the investigated populations, which either employ a pronounced cellular stress response in the inducible Hsp70 forms, or exhibit a comparatively high constitutive expression of Hsps (heat shock proteins) while showing only little response in terms of Hsp induction. Conclusions This study serves as a case study to explore the methodological prerequisites of physiological stress response comparisons among ecologically and phylogenetically different organisms. To improve the reliability of gene expression data and compare the stress responses of subpopulations under potential genetic divergence, reference gene stability algorithms are valuable and necessary tools. As the Hsp70 isoforms have been shown to play different roles in the acute stress responses and increased constitutive defenses of populations in their different habitats, these comparative studies can yield insight into physiological strategies of adaptation to environmental stress and provide hints for the prudent use of the cellular stress response as a biomarker to study environmental stress and stress adaptation of populations under changing environmental conditions. PMID:23680017

Physiology and the Biomedical Engineering Curriculum: Utilizing Emerging Instructional Technologies to Promote Development of Adaptive Expertise in Undergraduate Students

ERIC Educational Resources Information Center

Nelson, Regina K.

2013-01-01

A mixed-methods research study was designed to test whether undergraduate engineering students were better prepared to learn advanced topics in biomedical engineering if they learned physiology via a quantitative, concept-based approach rather than a qualitative, system-based approach. Experiments were conducted with undergraduate engineering…

Physiological responses to prolonged bed rest in humans: A compendium of research, 1981-1988

NASA Technical Reports Server (NTRS)

Luu, Phuong B.; Ortiz, Vanessa; Barnes, Paul R.; Greenleaf, John E.

1990-01-01

Clinical observations and results form more basic studies that help to elucidate the physiological mechanisms of the adaptation of humans to prolonged bed rest. If the authors' abstract or summary was appropriate, it was included. In some cases a more detailed synopsis was provided under the subheadings of purpose, methods, results, and conclusions.

Environmental physiology of a small marsupial inhabiting arid floodplains.

PubMed

Warnecke, L; Cooper, C E; Geiser, F; Withers, P C

2010-09-01

Giles' planigale (Planigale gilesi) is among the smallest extant marsupials and inhabits deep soil cracks in arid floodplains. We examined whether its physiology shows specific adaptations to its extreme habitat. Metabolic rate, body temperature, evaporative water loss and thermal conductance were measured for eight planigales (average mass 9 g) exposed to four different ambient temperatures ranging from 10 degrees C to 32 degrees C. Water economy and respiratory variables were measured for the first time in this species. All of these standard physiological variables conformed to allometrically-predicted values for a marsupial. All variables were significantly affected by ambient temperature, except tidal volume and dry thermal conductance. Metabolic rate increased substantially at low ambient temperatures, as required to maintain a relatively constant body temperature of about 32-34 degrees C. This increased oxygen demand was accommodated by increased ventilation rather than increased oxygen extraction. Planigales had a comparatively high point of relative water economy of 19.1 degrees C, consistent with their small body size and arid habitat. Torpor reduced energy expenditure by 79% and evaporative water loss by 62%. Our study suggests that torpor use, along with behavioural adaptations, suffice for P. gilesi to live underground in arid habitats without further physiological adaptations. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Variation in functional responses to water stress and differentiation between natural allopolyploid populations in the Brachypodium distachyon species complex.

PubMed

Martínez, Luisa M; Fernández-Ocaña, Ana; Rey, Pedro J; Salido, Teresa; Amil-Ruiz, Francisco; Manzaneda, Antonio J

2018-06-08

Some polyploid species show enhanced physiological tolerance to drought compared with their progenitors. However, very few studies have examined the consistency of physiological drought response between genetically differentiated natural polyploid populations, which is key to evaluation of the importance of adaptive evolution after polyploidization in those systems where drought exerts a selective pressure. A comparative functional approach was used to investigate differentiation of drought-tolerance-related traits in the Brachypodium species complex, a model system for grass polyploid adaptive speciation and functional genomics that comprises three closely related annual species: the two diploid parents, B. distachyon and B. stacei, and the allotetraploid derived from them, B. hybridum. Differentiation of drought-tolerance-related traits between ten genetically distinct B. hybridum populations and its ecological correlates was further analysed. The functional drought response is overall well differentiated between Brachypodium species. Brachypodium hybridum allotetraploids showed a transgressive expression pattern in leaf phytohormone content in response to drought. In contrast, other B. hybridum physiological traits correlated to B. stacei ones. Particularly, proline and water content were the traits that best discriminated these species from B. distachyon under drought. After polyploid formation and/or colonization, B. hybridum populations have adaptively diverged physiologically and genetically in response to variations in aridity.

[An increase in efficiency of adaptations and a weakening of organism protective reactions in the process of biological evolution].

PubMed

Ivanov, K P

2014-01-01

The main direction of evolution of living organisms is development of the central nervous system and sense organ, an increase of energy exchange development of homoiothermia, development of the more and more complex forms of behavior, an increase in energy expenditure in connection with an increase of the organism activity, and development of adaptation to the habitat. Such fundamental processes were subjected and have been subjected to numerous studies and discussions. However, in different animals there exist different species peculiarities of evolution of physiological functions, from which finally formed are fundamental evolutionary processes. We studied some of these specific processes by dividing them into two categories. The first category is "Increase of efficiency of adaptation" in development of biological evolution. By this term we mean development of amazing by perfection specific physiological mechanisms of adaptive character. The second category is "Weakening of protective organism reactions". By this we understand disturbance of protective mechanisms of the organism immune system, discoordination of movement of leukocytes along microvessels, the absence of efficient collateral circulation in brain and in heart, etc.

Spacelab Life Sciences 1: Reprints of Background Life Sciences Publications

NASA Technical Reports Server (NTRS)

White, Ronald (Editor); Leonard, Joel I. (Editor)

1991-01-01

The research being conducted on SLS-1 is primarily concerned with the short-term adaptation of physiological systems to weightlessness. A comprehensive overview of the various disciplines being studied on SLS-1 is presented. Citations and abstracts of all the papers submitted by the SLS-1 investigator teams are contained. The physiological systems studied include: cardiovascular and cardiopulmonary, musculoskeletal, neurovestibular, renal and endocrine, hematological, and immunological.

Parathyroid hormone, calcitonin, and vitamin D 1974: Present status of physiological studies and analysis of calcium homeostasis

NASA Technical Reports Server (NTRS)

Potts, J. T., Jr.; Swenson, K. G.

1975-01-01

The role of parathyroid hormone, calcitonin, and vitamin D in the control of calcium and bone metabolism was studied. Particular emphasis was placed on the physiological adaptation to weightlessness and, as a potential model for this purpose, on the immobilization characteristic of space flight or prolonged bed rest. The biosynthesis, control of secretion, and metabolism of these hormonal agents is considered.

Roy's Adaptation Model-Guided Education and Promoting the Adaptation of Veterans With Lower Extremities Amputation.

PubMed

Azarmi, Somayeh; Farsi, Zahra

2015-10-01

Any defect in extremities of the body can affect different life aspects. The purpose of this study was to investigate the effect of Roy's adaptation model-guided education on promoting the adaptation of veterans with lower extremities amputation. In a randomized clinical trial, 60 veterans with lower extremities amputation referring to Kowsar Orthotics and Prosthetics Center of veterans clinic in Tehran, Iran, were recruited with convenience method and were randomly assigned to intervention and control groups during 2013 - 2014. For data collection, Roy's adaptation model questionnaire was used. After completing the questionnaires in both groups, maladaptive behaviors were determined in the intervention group and an education program based on Roy's adaptation model was implemented. After two months, both groups completed the questionnaires again. Data was analyzed with SPSS software. Independent t-test showed statistically significant differences between the two groups in the post-test stage in terms of the total score of adaptation (P = 0.001) as well as physiologic (P = 0.0001) and role function modes (P = 0.004). The total score of adaptation (139.43 ± 5.45 to 127.54 ± 14.55, P = 0.006) as well as the scores of physiologic (60.26 ± 5.45 to 53.73 ± 7.79, P = 0.001) and role function (20.30 ± 2.42 to 18.13 ± 3.18, P = 0.01) modes in the intervention group significantly increased, whereas the scores of self-concept (42.10 ± 4.71 to 39.40 ± 5.67, P = 0.21) and interdependence (16.76 ± 2.22 to 16.30 ± 2.57, P = 0.44) modes in the two stages did not have a significant difference. Findings of this research indicated that the Roy's adaptation model-guided education promoted the adaptation level of physiologic and role function modes in veterans with lower extremities amputation. However, this intervention could not promote adaptation in self-concept and interdependence modes. More intervention is advised based on Roy's adaptation model for improving the adaptation of veterans with lower extremities.

Cardio Respiratory Adaptations with Long Term Personalized Exercise Program in a T12 Spinal Cord Injured Person

ERIC Educational Resources Information Center

Vasiliadis, Angelo; Christoulas, Kosmas; Evaggelinou, Christina; Vrabas, Ioannis

2009-01-01

The purpose of this study was to investigate the physiological adaptations in cardio respiratory endurance with a personalized exercise program with arm-cranking exercise in a paraplegic person (incomplete T12 spinal cord injury). A 32 year-old man with spinal cord injury (T12) participated in the present study performing 30 minutes arm cranking…

Loss of 'complexity' and aging. Potential applications of fractals and chaos theory to senescence

NASA Technical Reports Server (NTRS)

Lipsitz, L. A.; Goldberger, A. L.

1992-01-01

The concept of "complexity," derived from the field of nonlinear dynamics, can be adapted to measure the output of physiologic processes that generate highly variable fluctuations resembling "chaos." We review data suggesting that physiologic aging is associated with a generalized loss of such complexity in the dynamics of healthy organ system function and hypothesize that such loss of complexity leads to an impaired ability to adapt to physiologic stress. This hypothesis is supported by observations showing an age-related loss of complex variability in multiple physiologic processes including cardiovascular control, pulsatile hormone release, and electroencephalographic potentials. If further research supports this hypothesis, measures of complexity based on chaos theory and the related geometric concept of fractals may provide new ways to monitor senescence and test the efficacy of specific interventions to modify the age-related decline in adaptive capacity.

Mudskippers and Their Genetic Adaptations to an Amphibious Lifestyle

PubMed Central

You, Xinxin; Sun, Min; Li, Jia; Bian, Chao; Chen, Jieming; Yu, Hui; Shi, Qiong

2018-01-01

Simple Summary Mudskippers are an interesting group of goggle-eyed amphibious fish that can live both in water and on land. They are a useful model for obtaining insights into the genetic mechanisms underlying the terrestrial adaptations of amphibious fish. This review summarizes the morphological and physiological modifications of representative mudskippers, and focuses on the recent advancement of genomic studies on their genetic adaptations to the amphibious lifestyle. Abstract Mudskippers are the largest group of amphibious teleost fish that are uniquely adapted to live on mudflats. During their successful transition from aqueous life to terrestrial living, these fish have evolved morphological and physiological modifications of aerial vision and olfaction, higher ammonia tolerance, aerial respiration, improved immunological defense against terrestrial pathogens, and terrestrial locomotion using protruded pectoral fins. Comparative genomic and transcriptomic data have been accumulated and analyzed for understanding molecular mechanisms of the terrestrial adaptations. Our current review provides a general introduction to mudskippers and recent research advances of their genetic adaptations to the amphibious lifestyle, which will be helpful for understanding the evolutionary transition of vertebrates from water to land. Our insights into the genomes and transcriptomes will also support molecular breeding, functional identification, and natural compound screening. PMID:29414871

Three-Dimensional Normal Human Neural Progenitor Tissue-Like Assemblies: A Model for Persistent Varicell-Zoster Virus Infection and Platform to Study Viral Infectivity and Oxidative Stress and Damage

NASA Technical Reports Server (NTRS)

Goodwin, T. J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

2014-01-01

The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpesvirus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex threedimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6].

Simulation of physiological systems in order to evaluate and predict the human condition in a space flight

NASA Technical Reports Server (NTRS)

Verigo, V. V.

1979-01-01

Simulation models were used to study theoretical problems of space biology and medicine. The reaction and adaptation of the main physiological systems to the complex effects of space flight were investigated. Mathematical models were discussed in terms of their significance in the selection of the structure and design of biological life support systems.

A Physiological Case Study of a Paralympic Wheelchair Tennis Player: Reflective Practise

PubMed Central

Diaper, Nicholas J.; Goosey-Tolfrey, Victoria L.

2009-01-01

This study was designed to examine the physiological changes caused by long-term training in a world class female tennis player in preparation for a major championship. Additionally, we aim to describe the training interventions and determine a suitable cooling strategy that was to be used at the 2004 Paralympic Games. The athlete underwent regular physiological assessment during 2003-2004. Physiological measures involved body composition, submaximal and peak oxygen uptake and key variables associated with maximal sprinting. In addition, a suitable match-play cooling intervention and hydration strategy was also explored. Body composition improved over the course of the study. Aerobic capacity fell by 21%, yet the submaximal physiological variables such as lactate profile and pushing economy improved. The trade off of aerobic capacity was perhaps noticeably counter-balanced with the maintenance of the peak sprinting speed and improvement found in the fatigue profile across ten repeated sprints. The extensive training programme was responsible for these changes and these adaptations resulted in a more confident athlete, in peak physical condition leading into the Paralympic Games. It is difficult to appreciate the extent to which this work had an impact on tennis performance given the skill requirements of wheelchair tennis and this warrants future attention. Key points Physiological adaptations were apparent over the two-year training period. The training emphasis resulted in a reduction in aerobic capacity, yet an improvement in repetitive sprint performance was seen leading into the Major competition. An effective cooling technique was identified that could be used during wheelchair tennis performance. The athlete and coaches were complimentary to the physiological support provided, which resulted in a more confident athlete at the Paralympic Games. PMID:24149542

Is Aquatic Life Correlated with an Increased Hematocrit in Snakes?

PubMed Central

Brischoux, François; Gartner, Gabriel E. A.; Garland, Theodore; Bonnet, Xavier

2011-01-01

Background Physiological adaptations that allow air-breathing vertebrates to remain underwater for long periods mainly involve modifications of the respiratory system, essentially through increased oxygen reserves. Physiological constraints on dive duration tend to be less critical for ectotherms than for endotherms because the former have lower mass-specific metabolic rates. Moreover, comparative studies between marine and terrestrial ectotherms have yet to show overall distinct physiological differences specifically associated with oxygen reserves. Methodology/Principal Findings We used phylogenetically informed statistical models to test if habitat affects hematocrit (an indicator of blood oxygen stores) in snakes, a lineage that varies widely in habitat use. Our results indicate that both phylogenetic position (clade) and especially habitat are significant predictors of hematocrit. Our analysis also confirms the peculiar respiratory physiology of the marine Acrochordus granulatus. Conclusion/Significance Contrary to previous findings, marine snakes have significantly–albeit slightly–elevated hematocrit, which should facilitate increased aerobic dive times. Longer dives could have consequences for foraging, mate searching, and predation risks. Alternatively, but not exclusively, increased Hct in marine species might also help to fuel other oxygen-demanding physiological adaptations, such as those involved in osmoregulation. PMID:21359216

Acclimatization and Adaptive Capacity of Marine Species in a Changing Ocean.

PubMed

Foo, S A; Byrne, M

To persist in an ocean changing in temperature, pH and other stressors related to climate change, many marine species will likely need to acclimatize or adapt to avoid extinction. If marine populations possess adequate genetic variation in tolerance to climate change stressors, species might be able to adapt to environmental change. Marine climate change research is moving away from single life stage studies where individuals are directly placed into projected scenarios ('future shock' approach), to focus on the adaptive potential of populations in an ocean that will gradually change over coming decades. This review summarizes studies that consider the adaptive potential of marine invertebrates to climate change stressors and the methods that have been applied to this research, including quantitative genetics, laboratory selection studies and trans- and multigenerational experiments. Phenotypic plasticity is likely to contribute to population persistence providing time for genetic adaptation to occur. Transgenerational and epigenetic effects indicate that the environmental and physiological history of the parents can affect offspring performance. There is a need for long-term, multigenerational experiments to determine the influence of phenotypic plasticity, genetic variation and transgenerational effects on species' capacity to persist in a changing ocean. However, multigenerational studies are only practicable for short generation species. Consideration of multiple morphological and physiological traits, including changes in molecular processes (eg, DNA methylation) and long-term studies that facilitate acclimatization will be essential in making informed predictions of how the seascape and marine communities will be altered by climate change. © 2016 Elsevier Ltd. All rights reserved.

[Morpha striata in the members of the genus Rana (Amphibia, Anura), the reasons of adaptability to environmental changes].

PubMed

Vershinin, V L

2008-01-01

Under investigation is a complex of inherited physiological properties of the morpha striata (a monogenous dominant mutation) in two species of the genus Rana. Insufficient effectiveness of the potassium-sodium pump responsible for the skin transport in amphibians had lead to formation of a number of compensative physiological mechanisms in this morpha. The yearlings of the morpha striata are characterized by highly dynamic hemopoetic system playing important role in individual adaptations to unstable environments. Such a high level of metabolism in the morpha striata promotes rising of adaptive potential of the nervous system due to decrease of the excitability threshold, but causes shortening the life span. Therefore, physiological differences correlated with polymorph structure of the close species can be of crucial importance in their adaptations under existence in the natural and artificial geochemical anomalies and in anthropogenically disturbed ecosystems.

Principles of exercise physiology: responses to acute exercise and long-term adaptations to training.

PubMed

Rivera-Brown, Anita M; Frontera, Walter R

2012-11-01

Physical activity and fitness are associated with a lower prevalence of chronic diseases, such as heart disease, cancer, high blood pressure, and diabetes. This review discusses the body's response to an acute bout of exercise and long-term physiological adaptations to exercise training with an emphasis on endurance exercise. An overview is provided of skeletal muscle actions, muscle fiber types, and the major metabolic pathways involved in energy production. The importance of adequate fluid intake during exercise sessions to prevent impairments induced by dehydration on endurance exercise, muscular power, and strength is discussed. Physiological adaptations that result from regular exercise training such as increases in cardiorespiratory capacity and strength are mentioned. The review emphasizes the cardiovascular and metabolic adaptations that lead to improvements in maximal oxygen capacity. Copyright © 2012 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

COGNITIVE BEHAVIORAL STRESS MANAGEMENT EFFECTS ON PSYCHOSOCIAL AND PHYSIOLOGICAL ADAPTATION IN WOMEN UNDERGOING TREATMENT FOR BREAST CANCER

PubMed Central

Antoni, Michael H.; Lechner, Suzanne; Diaz, Alain; Vargas, Sara; Holley, Heather; Phillips, Kristin; McGregor, Bonnie; Carver, Charles S.; Blomberg, Bonnie

2009-01-01

BACKGROUND A diagnosis of breast cancer and treatment are psychologically stressful events, particularly over the first year after diagnosis. Women undergo many demanding and anxiety-arousing treatments such as surgery, radiation and chemotherapy. Psychosocial interventions that promote psychosocial adaptation to these challenges may modulate physiological processes (neuroendocrine and immune) that are relevant for health outcomes in breast cancer patients. METHODS Women with Stage 1 – 3 breast cancer recruited 4 – 8 weeks after surgery were randomized to either a 10-week group-based cognitive behavioral stress management (CBSM) intervention or a 1-day psychoeducational control group and completed questionnaires and late afternoon blood samples at study entry and 6 and 12 months after assignment to experimental condition. RESULTS Of 128 women initially providing psychosocial questionnaire and blood samples at study entry, 97 provided complete data for anxiety measures and cortisol analysis at all time points, and immune assays were run on a subset of 85 of these women. Those assigned to a 10-week group-based CBSM intervention evidenced better psychosocial adaptation (lower reported cancer-specific anxiety and interviewer-rated general anxiety symptoms) and physiological adaptation (lower cortisol, greater Th1 cytokine [interleukin-2 and interferon-γ production and IL-2:IL-4 ratio) after their adjuvant treatment compared to those in the control group. Effects on psychosocial adaptation indicators and cortisol appeared to hold across the entire 12-month observation period. Th1 cytokine regulation changes held only over the initial 6-month period. CONCLUSIONS This intervention may have facilitated a “recovery or maintenance” of Th1 cytokine regulation during or after the adjuvant therapy period. Behavioral interventions that address dysregulated neuroendocrine function could play a clinically significant role in optimizing host immunologic resistance during a vulnerable period. PMID:18835434

Adaptation to Altitude as a Vehicle for Experiential Learning of Physiology by University Undergraduates

ERIC Educational Resources Information Center

Weigle, David S.; Buben, Amelia; Burke, Caitlin C.; Carroll, Nels D.; Cook, Brett M.; Davis, Benjamin S.; Dubowitz, Gerald; Fisher, Rian E.; Freeman, Timothy C.; Gibbons, Stephen M.; Hansen, Hale A.; Heys, Kimberly A.; Hopkins, Brittany; Jordan, Brittany L.; McElwain, Katherine L.; Powell, Frank L.; Reinhart, Katherine E.; Robbins, Charles D.; Summers, Cameron C.; Walker, Jennifer D.; Weber, Steven S.; Weinheimer, Caroline J.

2007-01-01

In this article, an experiential learning activity is described in which 19 university undergraduates made experimental observations on each other to explore physiological adaptations to high altitude. Following 2 wk of didactic sessions and baseline data collection at sea level, the group ascended to a research station at 12,500-ft elevation.…

Evolutionary stasis and lability in thermal physiology in a group of tropical lizards.

PubMed

Muñoz, Martha M; Stimola, Maureen A; Algar, Adam C; Conover, Asa; Rodriguez, Anthony J; Landestoy, Miguel A; Bakken, George S; Losos, Jonathan B

2014-03-07

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming.

Evolutionary stasis and lability in thermal physiology in a group of tropical lizards

PubMed Central

Muñoz, Martha M.; Stimola, Maureen A.; Algar, Adam C.; Conover, Asa; Rodriguez, Anthony J.; Landestoy, Miguel A.; Bakken, George S.; Losos, Jonathan B.

2014-01-01

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming. PMID:24430845

Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait.

PubMed

Olofsson, Jill K; Bianconi, Matheus; Besnard, Guillaume; Dunning, Luke T; Lundgren, Marjorie R; Holota, Helene; Vorontsova, Maria S; Hidalgo, Oriane; Leitch, Ilia J; Nosil, Patrik; Osborne, Colin P; Christin, Pascal-Antoine

2016-12-01

Physiological novelties are often studied at macro-evolutionary scales such that their micro-evolutionary origins remain poorly understood. Here, we test the hypothesis that key components of a complex trait can evolve in isolation and later be combined by gene flow. We use C 4 photosynthesis as a study system, a derived physiology that increases plant productivity in warm, dry conditions. The grass Alloteropsis semialata includes C 4 and non-C 4 genotypes, with some populations using laterally acquired C 4 -adaptive loci, providing an outstanding system to track the spread of novel adaptive mutations. Using genome data from C 4 and non-C 4 A. semialata individuals spanning the species' range, we infer and date past migrations of different parts of the genome. Our results show that photosynthetic types initially diverged in isolated populations, where key C 4 components were acquired. However, rare but recurrent subsequent gene flow allowed the spread of adaptive loci across genetic pools. Indeed, laterally acquired genes for key C 4 functions were rapidly passed between populations with otherwise distinct genomic backgrounds. Thus, our intraspecific study of C 4 -related genomic variation indicates that components of adaptive traits can evolve separately and later be combined through secondary gene flow, leading to the assembly and optimization of evolutionary innovations. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Physiology and transcriptomics of water-deficit stress responses in wheat cultivars TAM 111 and TAM 112.

PubMed

Reddy, Srirama Krishna; Liu, Shuyu; Rudd, Jackie C; Xue, Qingwu; Payton, Paxton; Finlayson, Scott A; Mahan, James; Akhunova, Alina; Holalu, Srinidhi V; Lu, Nanyan

2014-09-01

Hard red winter wheat crops on the U.S. Southern Great Plains often experience moderate to severe drought stress, especially during the grain filling stage, resulting in significant yield losses. Cultivars TAM 111 and TAM 112 are widely cultivated in the region, share parentage and showed superior but distinct adaption mechanisms under water-deficit (WD) conditions. Nevertheless, the physiological and molecular basis of their adaptation remains unknown. A greenhouse study was conducted to understand the differences in the physiological and transcriptomic responses of TAM 111 and TAM 112 to WD stress. Whole-plant data indicated that TAM 112 used more water, produced more biomass and grain yield under WD compared to TAM 111. Leaf-level data at the grain filling stage indicated that TAM 112 had elevated abscisic acid (ABA) content and reduced stomatal conductance and photosynthesis as compared to TAM 111. Sustained WD during the grain filling stage also resulted in greater flag leaf transcriptome changes in TAM 112 than TAM 111. Transcripts associated with photosynthesis, carbohydrate metabolism, phytohormone metabolism, and other dehydration responses were uniquely regulated between cultivars. These results suggested a differential role for ABA in regulating physiological and transcriptomic changes associated with WD stress and potential involvement in the superior adaptation and yield of TAM 112. Copyright © 2014 Elsevier GmbH. All rights reserved.

Discrete physiological effects of beetroot juice and potassium nitrate supplementation following 4-wk sprint interval training.

PubMed

Thompson, Christopher; Vanhatalo, Anni; Kadach, Stefan; Wylie, Lee J; Fulford, Jonathan; Ferguson, Scott K; Blackwell, Jamie R; Bailey, Stephen J; Jones, Andrew M

2018-06-01

The physiological and exercise performance adaptations to sprint interval training (SIT) may be modified by dietary nitrate ([Formula: see text]) supplementation. However, it is possible that different types of [Formula: see text] supplementation evoke divergent physiological and performance adaptations to SIT. The purpose of this study was to compare the effects of 4-wk SIT with and without concurrent dietary [Formula: see text] supplementation administered as either [Formula: see text]-rich beetroot juice (BR) or potassium [Formula: see text] (KNO 3 ). Thirty recreationally active subjects completed a battery of exercise tests before and after a 4-wk intervention in which they were allocated to one of three groups: 1) SIT undertaken without dietary [Formula: see text] supplementation (SIT); 2) SIT accompanied by concurrent BR supplementation (SIT + BR); or 3) SIT accompanied by concurrent KNO 3 supplementation (SIT + KNO 3 ). During severe-intensity exercise, V̇o 2peak and time to task failure were improved to a greater extent with SIT + BR than SIT and SIT + KNO 3 ( P < 0.05). There was also a greater reduction in the accumulation of muscle lactate at 3 min of severe-intensity exercise in SIT + BR compared with SIT + KNO 3 ( P < 0.05). Plasma [Formula: see text] concentration fell to a greater extent during severe-intensity exercise in SIT + BR compared with SIT and SIT + KNO 3 ( P < 0.05). There were no differences between groups in the reduction in the muscle phosphocreatine recovery time constant from pre- to postintervention ( P > 0.05). These findings indicate that 4-wk SIT with concurrent BR supplementation results in greater exercise capacity adaptations compared with SIT alone and SIT with concurrent KNO 3 supplementation. This may be the result of greater NO-mediated signaling in SIT + BR compared with SIT + KNO 3 . NEW & NOTEWORTHY We compared the influence of different forms of dietary nitrate supplementation on the physiological and performance adaptations to sprint interval training (SIT). Compared with SIT alone, supplementation with nitrate-rich beetroot juice, but not potassium [Formula: see text], enhanced some physiological adaptations to training.

Behavioral and physiological adaptation to repeated chair restraint in rhesus macaques.

PubMed

Ruys, J D; Mendoza, S P; Capitanio, J P; Mason, W A

2004-09-15

Physical restraint is a commonly used procedure when working closely with nonhuman primates. Nonhuman primates show rapid behavioral changes when learning the restraint procedure, and these changes have been taken to reflect behavioral and physiological habituation to the procedure. This study examined the behavioral and adrenocortical responses to repeated physical restraint in a large sample of adult male rhesus monkeys. Subjects showed a decline in behavioral agitation and cortisol concentrations across seven consecutive days of restraint. The changes in adrenocortical responsiveness were also coincident with an increased sensitivity to dexamethasone and a change in early morning basal cortisol secretion. The subjects were restrained for a single session 6 months later, and while the reduction in behavioral agitation was still present, the majority of changes in adrenocortical responsiveness were no longer present. These data show that behavior is not necessarily an indicator of underlying physiological processes and that the reduction of hypothalamic-pituitary-adrenal (HPA) activity with repeated restraint is due to physiological adaptation to high glucocorticoid concentrations and not to psychological habituation to the restraint procedures.

Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates.

PubMed

Storz, Jay F; Scott, Graham R; Cheviron, Zachary A

2010-12-15

High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change.

Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates

PubMed Central

Storz, Jay F.; Scott, Graham R.; Cheviron, Zachary A.

2010-01-01

High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change. PMID:21112992

Macular Bioaccelerometers on Earth and in Space

NASA Technical Reports Server (NTRS)

Ross, M. D.; Cutler, L.; Meyer, G.; Vazin, P.; Lam, T.

1991-01-01

Space flight offers the opportunity to study linear bioaccelerometers (vestibular maculas) in the virtual absence of a primary stimulus, gravitational acceleration. Macular research in space is particularly important to NASA because the bioaccelerometers are proving to be weighted neural networks in which information is distributed for parallel processing. Neural networks are plastic and highly adaptive to new environments. Combined morphological-physiological studies of maculas fixed in space and following flight should reveal macular adaptive responses to microgravity, and their time-course. Ground-based research, already begun, using computer-assisted, 3-dimensional reconstruction of macular terminal fields will lead to development of computer models of functioning maculas. This research should continue in conjunction with physiological studies, including work with multichannel electrodes. The results of such a combined effort could usher in a new era in understanding vestibular function on Earth and in space. They can also provide a rational basis for counter-measures to space motion sickness, which may prove troublesome as space voyager encounter new gravitational fields on planets, or must re-adapt to 1 g upon return to earth.

Adaptive Filtration of Physiological Artifacts in EEG Signals in Humans Using Empirical Mode Decomposition

NASA Astrophysics Data System (ADS)

Grubov, V. V.; Runnova, A. E.; Hramov, A. E.

2018-05-01

A new method for adaptive filtration of experimental EEG signals in humans and for removal of different physiological artifacts has been proposed. The algorithm of the method includes empirical mode decomposition of EEG, determination of the number of empirical modes that are considered, analysis of the empirical modes and search for modes that contains artifacts, removal of these modes, and reconstruction of the EEG signal. The method was tested on experimental human EEG signals and demonstrated high efficiency in the removal of different types of physiological EEG artifacts.

Ambiguous Tilt and Translation Motion Cues after Space Flight and Otolith Assessment during Post-Flight Re-Adaptation

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Clarke, A. H.; Harm, D. L.; Rupert, A. H.; Clement, G. R.

2009-01-01

Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation and perceptual illusions following Gtransitions. These studies are designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short duration space flights.

Adaptation to Chronic Nutritional Stress Leads to Reduced Dependence on Microbiota in Drosophila melanogaster.

PubMed

Erkosar, Berra; Kolly, Sylvain; van der Meer, Jan R; Kawecki, Tadeusz J

2017-10-24

Numerous studies have shown that animal nutrition is tightly linked to gut microbiota, especially under nutritional stress. In Drosophila melanogaster , microbiota are known to promote juvenile growth, development, and survival on poor diets, mainly through enhanced digestion leading to changes in hormonal signaling. Here, we show that this reliance on microbiota is greatly reduced in replicated Drosophila populations that became genetically adapted to a poor larval diet in the course of over 170 generations of experimental evolution. Protein and polysaccharide digestion in these poor-diet-adapted populations became much less dependent on colonization with microbiota. This was accompanied by changes in expression levels of dFOXO transcription factor, a key regulator of cell growth and survival, and many of its targets. These evolutionary changes in the expression of dFOXO targets to a large degree mimic the response of the same genes to microbiota, suggesting that the evolutionary adaptation to poor diet acted on mechanisms that normally mediate the response to microbiota. Our study suggests that some metazoans have retained the evolutionary potential to adapt their physiology such that association with microbiota may become optional rather than essential. IMPORTANCE Animals depend on gut microbiota for various metabolic tasks, particularly under conditions of nutritional stress, a relationship usually regarded as an inherent aspect of animal physiology. Here, we use experimental evolution in fly populations to show that the degree of host dependence on microbiota can substantially and rapidly change as the host population evolves in response to poor diet. Our results suggest that, although microbiota may initially greatly facilitate coping with suboptimal diets, chronic nutritional stress experienced over multiple generations leads to evolutionary adaptation in physiology and gut digestive properties that reduces dependence on the microbiota for growth and survival. Thus, despite its ancient evolutionary history, the reliance of animal hosts on their microbial partners can be surprisingly flexible and may be relaxed by short-term evolution. Copyright © 2017 Erkosar et al.

Integrated Physiological, Proteomic, and Metabolomic Analysis of Ultra Violet (UV) Stress Responses and Adaptation Mechanisms in Pinus radiata*

PubMed Central

Pascual, Jesús; Cañal, María Jesús; Escandón, Mónica; Meijón, Mónica; Weckwerth, Wolfram

2017-01-01

Globally expected changes in environmental conditions, especially the increase of UV irradiation, necessitate extending our knowledge of the mechanisms mediating tree species adaptation to this stress. This is crucial for designing new strategies to maintain future forest productivity. Studies focused on environmentally realistic dosages of UV irradiation in forest species are scarce. Pinus spp. are commercially relevant trees and not much is known about their adaptation to UV. In this work, UV treatment and recovery of Pinus radiata plants with dosages mimicking future scenarios, based on current models of UV radiation, were performed in a time-dependent manner. The combined metabolome and proteome analysis were complemented with measurements of + physiological parameters and gene expression. Sparse PLS analysis revealed complex molecular interaction networks of molecular and physiological data. Early responses prevented phototoxicity by reducing photosystem activity and the electron transfer chain together with the accumulation of photoprotectors and photorespiration. Apart from the reduction in photosynthesis as consequence of the direct UV damage on the photosystems, the primary metabolism was rearranged to deal with the oxidative stress while minimizing ROS production. New protein kinases and proteases related to signaling, coordination, and regulation of UV stress responses were revealed. All these processes demonstrate a complex molecular interaction network extending the current knowledge on UV-stress adaptation in pine. PMID:28096192

Multivariate Dynamical Modeling to Investigate Human Adaptation to Space Flight: Initial Concepts

NASA Technical Reports Server (NTRS)

Shelhamer, Mark; Mindock, Jennifer; Zeffiro, Tom; Krakauer, David; Paloski, William H.; Lumpkins, Sarah

2014-01-01

The array of physiological changes that occur when humans venture into space for long periods presents a challenge to future exploration. The changes are conventionally investigated independently, but a complete understanding of adaptation requires a conceptual basis founded in intergrative physiology, aided by appropriate mathematical modeling. NASA is in the early stages of developing such an approach.

Multivariate Dynamic Modeling to Investigate Human Adaptation to Space Flight: Initial Concepts

NASA Technical Reports Server (NTRS)

Shelhamer, Mark; Mindock, Jennifer; Zeffiro, Tom; Krakauer, David; Paloski, William H.; Lumpkins, Sarah

2014-01-01

The array of physiological changes that occur when humans venture into space for long periods presents a challenge to future exploration. The changes are conventionally investigated independently, but a complete understanding of adaptation requires a conceptual basis founded in integrative physiology, aided by appropriate mathematical modeling. NASA is in the early stages of developing such an approach.

Predicting organismal vulnerability to climate warming: roles of behaviour, physiology and adaptation.

PubMed

Huey, Raymond B; Kearney, Michael R; Krockenberger, Andrew; Holtum, Joseph A M; Jess, Mellissa; Williams, Stephen E

2012-06-19

A recently developed integrative framework proposes that the vulnerability of a species to environmental change depends on the species' exposure and sensitivity to environmental change, its resilience to perturbations and its potential to adapt to change. These vulnerability criteria require behavioural, physiological and genetic data. With this information in hand, biologists can predict organisms most at risk from environmental change. Biologists and managers can then target organisms and habitats most at risk. Unfortunately, the required data (e.g. optimal physiological temperatures) are rarely available. Here, we evaluate the reliability of potential proxies (e.g. critical temperatures) that are often available for some groups. Several proxies for ectotherms are promising, but analogous ones for endotherms are lacking. We also develop a simple graphical model of how behavioural thermoregulation, acclimation and adaptation may interact to influence vulnerability over time. After considering this model together with the proxies available for physiological sensitivity to climate change, we conclude that ectotherms sharing vulnerability traits seem concentrated in lowland tropical forests. Their vulnerability may be exacerbated by negative biotic interactions. Whether tropical forest (or other) species can adapt to warming environments is unclear, as genetic and selective data are scant. Nevertheless, the prospects for tropical forest ectotherms appear grim.

Human Physiological Responses to Acute and Chronic Cold Exposure

NASA Technical Reports Server (NTRS)

Stocks, Jodie M.; Taylor, Nigel A. S.; Tipton, Michael J.; Greenleaf, John E.

2001-01-01

When inadequately protected humans are exposed to acute cold, excessive body heat is lost to the environment and unless heat production is increased and heat loss attenuated, body temperature will decrease. The primary physiological responses to counter the reduction in body temperature include marked cutaneous vasoconstriction and increased metabolism. These responses, and the hazards associated with such exposure, are mediated by a number of factors which contribute to heat production and loss. These include the severity and duration of the cold stimulus; exercise intensity; the magnitude of the metabolic response; and individual characteristics such as body composition, age, and gender. Chronic exposure to a cold environment, both natural and artificial, results in physiological alterations leading to adaptation. Three quite different, but not necessarily exclusive, patterns of human cold adaptation have been reported: metabolic, hypothermic, and insulative. Cold adaptation has also been associated with an habituation response, in which there is a desensitization, or damping, of the normal response to a cold stress. This review provides a comprehensive analysis of the human physiological and pathological responses to cold exposure. Particular attention is directed to the factors contributing to heat production and heat loss during acute cold stress, and the ability of humans to adapt to cold environments.

Best of both worlds: simultaneous high-light and shade-tolerance adaptations within individual leaves of the living stone Lithops aucampiae.

PubMed

Field, Katie J; George, Rachel; Fearn, Brian; Quick, W Paul; Davey, Matthew P

2013-01-01

"Living stones" (Lithops spp.) display some of the most extreme morphological and physiological adaptations in the plant kingdom to tolerate the xeric environments in which they grow. The physiological mechanisms that optimise the photosynthetic processes of Lithops spp. while minimising transpirational water loss in both above- and below-ground tissues remain unclear. Our experiments have shown unique simultaneous high-light and shade-tolerant adaptations within individual leaves of Lithops aucampiae. Leaf windows on the upper surfaces of the plant allow sunlight to penetrate to photosynthetic tissues within while sunlight-blocking flavonoid accumulation limits incoming solar radiation and aids screening of harmful UV radiation. Increased concentration of chlorophyll a and greater chlorophyll a:b in above-ground regions of leaves enable maximum photosynthetic use of incoming light, while inverted conical epidermal cells, increased chlorophyll b, and reduced chlorophyll a:b ensure maximum absorption and use of low light levels within the below-ground region of the leaf. High NPQ capacity affords physiological flexibility under variable natural light conditions. Our findings demonstrate unprecedented physiological flexibility in a xerophyte and further our understanding of plant responses and adaptations to extreme environments.

Two years of combined high-intensity physical training and heat acclimatization affect lymphocyte and serum HSP70 in purebred military working dogs.

PubMed

Bruchim, Yaron; Aroch, Itamar; Eliav, Ady; Abbas, Atallah; Frank, Ilan; Kelmer, Efrat; Codner, Carolina; Segev, Gilad; Epstein, Yoram; Horowitz, Michal

2014-07-15

Military working dogs in hot countries undergo exercise training at high ambient temperatures for at least 9 mo annually. Physiological adaptations to these harsh conditions have been extensively studied; however, studies focusing on the underlying molecular adaptations are limited. In the current study, military working dogs were chosen as a model to examine the effects of superimposing endurance exercise on seasonal acclimatization to environmental heat stress. The lymphocyte HSP70 profile and extracellular HSP70 were studied in tandem with physiological performance in the dogs from their recruitment for the following 2 yr. Aerobic power and heat shock proteins were measured at the end of each summer, with physical performance tests (PPTs) in an acclimatized room (22°C). The study shows that together with a profound enhancement of aerobic power and physical performance, hsp72 mRNA induction immediately post-PPT and 45 min later, progressively increased throughout the study period (relative change in median lymphocyte hsp72 mRNA first PPT, 4.22 and 12.82; second PPT, 17.19 and 109.05, respectively), whereas induction of HSP72 protein was stable. These responses suggest that cellular/molecular adaptive tools for maintaining HSP72 homeostasis exist. There was also a significant rise in basal and peak median optical density extracellular HSP at the end of each exercise test (first PPT, 0.13 and 0.15; second PPT, 1.04 and 1.52, respectively). The relationship between these enhancements and improved aerobic power capacity is not yet fully understood. Copyright © 2014 the American Physiological Society.

How insects overcome two-component plant chemical defence: plant β-glucosidases as the main target for herbivore adaptation.

PubMed

Pentzold, Stefan; Zagrobelny, Mika; Rook, Fred; Bak, Søren

2014-08-01

Insect herbivory is often restricted by glucosylated plant chemical defence compounds that are activated by plant β-glucosidases to release toxic aglucones upon plant tissue damage. Such two-component plant defences are widespread in the plant kingdom and examples of these classes of compounds are alkaloid, benzoxazinoid, cyanogenic and iridoid glucosides as well as glucosinolates and salicinoids. Conversely, many insects have evolved a diversity of counteradaptations to overcome this type of constitutive chemical defence. Here we discuss that such counter-adaptations occur at different time points, before and during feeding as well as during digestion, and at several levels such as the insects’ feeding behaviour, physiology and metabolism. Insect adaptations frequently circumvent or counteract the activity of the plant β-glucosidases, bioactivating enzymes that are a key element in the plant’s two-component chemical defence. These adaptations include host plant choice, non-disruptive feeding guilds and various physiological adaptations as well as metabolic enzymatic strategies of the insect’s digestive system. Furthermore, insect adaptations often act in combination, may exist in both generalists and specialists, and can act on different classes of defence compounds. We discuss how generalist and specialist insects appear to differ in their ability to use these different types of adaptations: in generalists, adaptations are often inducible, whereas in specialists they are often constitutive. Future studies are suggested to investigate in detail how insect adaptations act in combination to overcome plant chemical defences and to allow ecologically relevant conclusions.

Evaluation of adaptation to visually induced motion sickness based on the maximum cross-correlation between pulse transmission time and heart rate.

PubMed

Sugita, Norihiro; Yoshizawa, Makoto; Abe, Makoto; Tanaka, Akira; Watanabe, Takashi; Chiba, Shigeru; Yambe, Tomoyuki; Nitta, Shin-ichi

2007-09-28

Computer graphics and virtual reality techniques are useful to develop automatic and effective rehabilitation systems. However, a kind of virtual environment including unstable visual images presented to wide field screen or a head mounted display tends to induce motion sickness. The motion sickness induced in using a rehabilitation system not only inhibits effective training but also may harm patients' health. There are few studies that have objectively evaluated the effects of the repetitive exposures to these stimuli on humans. The purpose of this study is to investigate the adaptation to visually induced motion sickness by physiological data. An experiment was carried out in which the same video image was presented to human subjects three times. We evaluated changes of the intensity of motion sickness they suffered from by a subjective score and the physiological index rho(max), which is defined as the maximum cross-correlation coefficient between heart rate and pulse wave transmission time and is considered to reflect the autonomic nervous activity. The results showed adaptation to visually-induced motion sickness by the repetitive presentation of the same image both in the subjective and the objective indices. However, there were some subjects whose intensity of sickness increased. Thus, it was possible to know the part in the video image which related to motion sickness by analyzing changes in rho(max) with time. The physiological index, rho(max), will be a good index for assessing the adaptation process to visually induced motion sickness and may be useful in checking the safety of rehabilitation systems with new image technologies.

Different profiles of decision making and physiology under varying levels of stress in trained military personnel.

PubMed

Gamble, Katherine R; Vettel, Jean M; Patton, Debra J; Eddy, Marianna D; Caroline Davis, F; Garcia, Javier O; Spangler, Derek P; Thayer, Julian F; Brooks, Justin R

2018-03-23

Decision making is one of the most vital processes we use every day, ranging from mundane decisions about what to eat to life-threatening choices such as how to avoid a car collision. Thus, the context in which our decisions are made is critical, and our physiology enables adaptive responses that account for how environmental stress influences our performance. The relationship between stress and decision making can additionally be affected by one's expertise in making decisions in high-threat environments, where experts can develop an adaptive response that mitigates the negative impacts of stress. In the present study, 26 male military personnel made friend/foe discriminations in an environment where we manipulated the level of stress. In the high-stress condition, participants received a shock when they incorrectly shot a friend or missed shooting a foe; in the low-stress condition, participants received a vibration for an incorrect decision. We characterized performance using signal detection theory to investigate whether a participant changed their decision criterion to avoid making an error. Results showed that under high-stress, participants made more false alarms, mistaking friends as foes, and this co-occurred with increased high frequency heart rate variability. Finally, we examined the relationship between decision making and physiology, and found that participants exhibited adaptive behavioral and physiological profiles under different stress levels. We interpret this adaptive profile as a marker of an expert's ingrained training that does not require top down control, suggesting a way that expert training in high-stress environments helps to buffer negative impacts of stress on performance. Published by Elsevier B.V.

Psychological Distress and Physiological Reactivity During In Vivo Exposure in People With Aviophobia.

PubMed

Busscher, Bert; Spinhoven, Philip; de Geus, Eco J C

2015-09-01

Exposure is regarded to be a crucial component of therapies for phobias. According to emotional processing theory, the success of exposure therapy is predicted by activation of subjective and physiological fear responses and their within-session habituation and between-session adaptation. This study tested this prediction for aviophobia. Seventy-nine participants following a highly standardized treatment program for aviophobia provided self-reported and physiological (heart rate, respiratory sinus arrhythmia and pre-ejection period) measurements of fear activation, within-session habituation, and between-session adaptation during exposure to flight-related stimuli, a flight simulator, and during two real flights. Multiple regression analyses were conducted to examine whether these measurements predicted therapy outcome up to 3 years after finishing therapy, including number of flights flown in this period. Both subjective and physiological arousal measurements indicated strong fear activation and large within-session habituation and between-session adaptation during exposure. Flight anxiety measures showed large improvements up to 3 years after treatment (η between 0.72 and 0.91). Lower self-reported anxiety during flight exposure was associated with lower flight anxiety after exposure (R = 0.15) and more flights flown (R = 0.14). Within-flight habituation or between-session adaptation of self-reported anxiety had no relationship with treatment outcome. Within-flight habituation of HR reactivity (R = 0.10) and respiratory sinus arrhythmia reactivity (R = 0.11) was associated with lower flight anxiety directly after the flight, but not on flight anxiety 3 years after finishing therapy or on long-term flying behavior. The results provide only weak support for emotional processing theory. Low self-reported anxiety during in vivo flight exposure was the best predictor of successful long-term therapy outcome.

Dynamic adjustments of cognitive control: oscillatory correlates of the conflict adaptation effect.

PubMed

Pastötter, Bernhard; Dreisbach, Gesine; Bäuml, Karl-Heinz T

2013-12-01

It is a prominent idea that cognitive control mediates conflict adaptation, in that response conflict in a previous trial triggers control adjustments that reduce conflict in a current trial. In the present EEG study, we investigated the dynamics of cognitive control in a response-priming task by examining the effects of previous trial conflict on intertrial and current trial oscillatory brain activities, both on the electrode and the source level. Behavioral results showed conflict adaptation effects for RTs and response accuracy. Physiological results showed sustained intertrial effects in left parietal theta power, originating in the left inferior parietal cortex, and midcentral beta power, originating in the left and right (pre)motor cortex. Moreover, physiological analysis revealed a current trial conflict adaptation effect in midfrontal theta power, originating in the ACC. Correlational analyses showed that intertrial effects predicted conflict-induced midfrontal theta power in currently incongruent trials. In addition, conflict adaptation effects in midfrontal theta power and RTs were positively related. Together, these findings point to a dynamic cognitive control system that, as a function of previous trial type, up- and down-regulates attention and preparatory motor activities in anticipation of the next trial.

Physiologic and behavioral effects of papoose board on anxiety in dental patients with special needs.

PubMed

Chen, Hsin-Yung; Yang, Hsiang; Chi, Huang-Ju; Chen, Hsin-Ming

2014-02-01

Anxiety induced by dental treatment can become a serious problem, especially for patients with special needs. Application of deep touch pressure, which is a sensory adaptation technique, may ameliorate anxiety in disabled patients. However, few empiric studies have investigated the possible links between the clinical effects of deep touch pressure and its behavioral and physiologic aspects. Equally little progress has been made concerning theoretical development. The current study is a crossover intervention trial to investigate the behavioral and physiological effects of deep touch pressure for participants receiving dental treatment. Nineteen disabled participants, who were retrospectively subclassified for positive trend or negative trend, were recruited to receive the papoose board as an application of deep touch pressure. Quantitative analyses of behavioral assessments and physiological measurements, including electrodermal activity and heart rate variability, were conducted. We sought to understand the modulation of the autonomic nervous system and the orchestration of sympathetic and parasympathetic (PsNS) nervous systems. Behavioral assessments reported that higher levels of anxiety were induced by the dental treatment for participants with both groups of positive and negative trends. Although no significant differences were found in the SNS activity, physiologic responses indicated that significantly changes of PsNS activity were observed under the stress condition (dental treatment) when deep touch pressure intervention was applied, especially for participants in the group of positive trend. Our results suggest that the PsNS activation plays a critical role in the process of ANS modulation. This study provides not only physiologic evidence for the modulation effects of deep touch pressure on stressful conditions in dental environments but also the evidence that the application of papoose board, as a sensory adaptation technique, is not harmful for dental patients with special needs. Copyright © 2012. Published by Elsevier B.V.

Human Adaptation To Isolated And Confined Environments

NASA Technical Reports Server (NTRS)

Evans, Gary W.; Stokols, Daniel; Carrere, Sna Sybil

1992-01-01

Data from Antarctic research station analyzed. Report describes study of physiology and psychology of humans in isolated and confined environment. Suggests ways in which such environments made more acceptable to human inhabitants.

The interruption of thyroid and interrenal and the inter-hormonal interference in fish: does it promote physiologic adaptation or maladaptation?

PubMed

Peter, Valsa S; Peter, M C Subhash

2011-12-01

Endocrines, the chief components of chemical centers which produce hormones in tune with intrinsic and extrinsic clues, create a chemical bridge between the organism and the environment. In fishes also hormones integrate and modulate many physiologic functions and its synthesis, release, biological actions and metabolic clearance are well regulated. Consequently, thyroid hormones (THs) and cortisol, the products of thyroid and interrenal axes, have been identified for their common integrative actions on metabolic and osmotic functions in fish. On the other hand, many anthropogenic chemical substances, popularly known as endocrine disrupting chemicals, have been shown to disrupt the hormone-receptor signaling pathways in a number fish species. These chemicals which are known for their ability to induce endocrine disruption particularly on thyroid and interrenals can cause malfunction or maladaptation of many vital processes which are involved in the development, growth and reproduction in fish. On the contrary, evidence is presented that the endocrine interrupting agents (EIAs) can cause interruption of thyroid and interrenals, resulting in physiologic compensatory mechanisms which can be adaptive, though such hormonal interactions are less recognized in fishes. The EIAs of physical, chemical and biological origins can specifically interrupt and modify the hormonal interactions between THs and cortisol, resulting in specific patterns of inter-hormonal interference. The physiologic analysis of these inter-hormonal interruptions during acclimation and post-acclimation to intrinsic or extrinsic EIAs reveals that combinations of anti-hormonal, pro-hormonal or stati-hormonal interference may help the fish to fine-tune their metabolic and osmotic performances as part of physiologic adaptation. This novel hypothesis on the phenomenon of inter-hormonal interference and its consequent physiologic interference during thyroid and interrenal interruption thus forms the basis of physiologic acclimation. This interfering action of TH and cortisol during hormonal interruption may subsequently promote ecological adaptation in fish as these physiologic processes ultimately favor them to survive in their hostile environment. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of a skiing intervention on the psycho-physiological reactivity and recovery in the elderly.

PubMed

Finkenzeller, T; Müller, E; Amesberger, G

2011-08-01

This study determined the effects of a skiing intervention lasting 12 weeks on the psycho-physiological reactivity to and recovery from mental stressors in individuals who are 60+ years of age. In accordance with the cross-stressor hypothesis, it was assumed that a skiing intervention optimizes psycho-physiological pre-conditions for coping with stress. A cognitive task was used to investigate stress-induced changes (reactivity) in the high-frequency (HF) component of the heart rate variability (HRV) and in the skin conductance level (SCL) as well as recovery from this stressor. The intervention group demonstrated a significant increase in maximal oxygen consumption that was not accompanied by alterations in HRV at rest. In comparison with the control group, there was no difference in the alteration of the reactivity and recovery in the HF component and in the SCL after completing the training. The findings indicate that neither the psycho-physiological reactivity nor the recovery was influenced by the skiing intervention. It may be speculated that the intensity of the skiing intervention was too low to induce such adaptations. Therefore, further studies are encouraged to enhance the duration and intensity of the exercises to achieve adaptations of the autonomous nervous system of elderly individuals. © 2011 John Wiley & Sons A/S.

Space physiology II: adaptation of the central nervous system to space flight--past, current, and future studies.

PubMed

Clément, Gilles; Ngo-Anh, Jennifer Thu

2013-07-01

Experiments performed in orbit on the central nervous system have focused on the control of posture, eye movements, spatial orientation, as well as cognitive processes, such as three-dimensional visual perception and mental representation of space. Brain activity has also been recorded during and immediately after space flight for evaluating the changes in brain structure activation during tasks involving perception, attention, memory, decision, and action. Recent ground-based studies brought evidence that the inputs from the neurovestibular system also participate in orthostatic intolerance. It is, therefore, important to revisit the flight data of neuroscience studies in the light of new models of integrative physiology. The outcomes of this exercise will increase our knowledge on the adaptation of body functions to changing gravitational environment, vestibular disorders, aging, and our approach towards more effective countermeasures during human space flight and planetary exploration.

[Optimization of the parameters of microcirculatory structural adaptation model based on improved quantum-behaved particle swarm optimization algorithm].

PubMed

Pan, Qing; Yao, Jialiang; Wang, Ruofan; Cao, Ping; Ning, Gangmin; Fang, Luping

2017-08-01

The vessels in the microcirculation keep adjusting their structure to meet the functional requirements of the different tissues. A previously developed theoretical model can reproduce the process of vascular structural adaptation to help the study of the microcirculatory physiology. However, until now, such model lacks the appropriate methods for its parameter settings with subsequent limitation of further applications. This study proposed an improved quantum-behaved particle swarm optimization (QPSO) algorithm for setting the parameter values in this model. The optimization was performed on a real mesenteric microvascular network of rat. The results showed that the improved QPSO was superior to the standard particle swarm optimization, the standard QPSO and the previously reported Downhill algorithm. We conclude that the improved QPSO leads to a better agreement between mathematical simulation and animal experiment, rendering the model more reliable in future physiological studies.

Virtual reality adaptive stimulation of limbic networks in the mental readiness training.

PubMed

Cosić, Kresimir; Popović, Sinisa; Kostović, Ivica; Judas, Milos

2010-01-01

A significant proportion of severe psychological problems in recent large-scale peacekeeping operations underscores the importance of effective methods for strengthening the stress resilience. Virtual reality (VR) adaptive stimulation, based on the estimation of the participant's emotional state from physiological signals, may enhance the mental readiness training (MRT). Understanding neurobiological mechanisms by which the MRT based on VR adaptive stimulation can affect the resilience to stress is important for practical application in the stress resilience management. After the delivery of a traumatic audio-visual stimulus in the VR, the cascade of events occurs in the brain, which evokes various physiological manifestations. In addition to the "limbic" emotional and visceral brain circuitry, other large-scale sensory, cognitive, and memory brain networks participate with less known impact in this physiological response. The MRT based on VR adaptive stimulation may strengthen the stress resilience through targeted brain-body interactions. Integrated interdisciplinary efforts, which would integrate the brain imaging and the proposed approach, may contribute to clarifying the neurobiological foundation of the resilience to stress.

Impact of environmental adaptation on tear film assessments.

PubMed

Fagehi, R

2018-03-01

The purpose of this study was to investigate the effect of ocular environmental adaptation on clinical tear film assessment. Thirty subjects (male, mean age 23±2.5) participated in this study. A number of clinical tear film tests were applied, including: fluorescein tear break-up time (FTBUT), Schirmer test and tear prism height test (TPH). The tear physiology of each subject was evaluated twice, once immediately when they arrived from the external environment, and then after 30minutes adaptation in the exam room environment. The mean values were: Schirmer test A (22.1±2.99), Schirmer test B (24.2±2.63), FTBUT A (8.00±1.94), FTBUT B (9.13±2.04), TPH A (0.179±0.026) and TPH B* (0.187±0.023). Statistical testing using Wilcoxon-signed rank test showed a significant difference between the Schirmer test results measured at the different times (P=0.008). Also, the FTBUT and tear prism height test results showed significant differences between the two evaluation times, (P=0.001, 0.011, respectively) (A: tear assessed when the subject comes from the outside environment, B: tear film assessed after 30min adaptation in the clinical environment). This study showed a significant difference between the tear film test results evaluated when the subjects were assessed immediately from the outside environment and after an adaptation time in the clinic environment. Practitioners must consider the effect of differences between external and clinical environment adaptation on clinical tear film physiology. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

The lugworm Arenicola marina: A model of physiological adaptation to life in intertidal sediments

NASA Astrophysics Data System (ADS)

Zebe, E.; Schiedek, D.

1996-03-01

The results of more than two decades of intensive research on the physiological and biochemical features of the lugworm are reviewed with the aim of drawing a general and comprehensive picture of the adaptation of this species to the special conditions of living in the tidal zone, which may also hold true for the majority of invertebrates found in this habitat.

Sensory Adapted Dental Environments to Enhance Oral Care for Children with Autism Spectrum Disorders: A Randomized Controlled Pilot Study

PubMed Central

Cermak, Sharon A.; Stein Duker, Leah I.; Williams, Marian E.; Dawson, Michael E.; Lane, Christianne J.; Polido, José C.

2015-01-01

This pilot and feasibility study examined the impact of a sensory adapted dental environment (SADE) to reduce distress, sensory discomfort, and perception of pain during oral prophylaxis for children with autism spectrum disorder (ASD). Participants were 44 children ages 6-12 (n=22 typical, n=22 ASD). In an experimental crossover design, each participant underwent two professional dental cleanings, one in a regular dental environment (RDE) and one in a SADE, administered in a randomized and counterbalanced order three to four months apart. Outcomes included measures of physiological anxiety, behavioral distress, pain intensity, and sensory discomfort. Both groups exhibited decreased physiological anxiety and reported lower pain and sensory discomfort in the SADE condition compared to RDE, indicating a beneficial effect of the SADE. PMID:25931290

Adaptation of exercise-induced stress in well-trained healthy young men.

PubMed

JanssenDuijghuijsen, Lonneke M; Keijer, Jaap; Mensink, Marco; Lenaerts, Kaatje; Ridder, Lars; Nierkens, Stefan; Kartaram, Shirley W; Verschuren, Martie C M; Pieters, Raymond H H; Bas, Richard; Witkamp, Renger F; Wichers, Harry J; van Norren, Klaske

2017-01-01

What is the central question of this study? Exercise is known to induce stress-related physiological responses, such as changes in intestinal barrier function. Our aim was to determine the test-retest repeatability of these responses in well-trained individuals. What is the main finding and its importance? Responses to strenuous exercise, as indicated by stress-related markers such as intestinal integrity markers and myokines, showed high test-retest variation. Even in well-trained young men an adapted response is seen after a single repetition after 1 week. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. Strenuous exercise induces different stress-related physiological changes, potentially including changes in intestinal barrier function. In the Protégé Study (ISRCTN14236739; www.isrctn.com), we determined the test-retest repeatability in responses to exercise in well-trained individuals. Eleven well-trained men (27 ± 4 years old) completed an exercise protocol that consisted of intensive cycling intervals, followed by an overnight fast and an additional 90 min cycling phase at 50% of maximal workload the next morning. The day before (rest), and immediately after the exercise protocol (exercise) a lactulose and rhamnose solution was ingested. Markers of energy metabolism, lactulose-to-rhamnose ratio, several cytokines and potential stress-related markers were measured at rest and during exercise. In addition, untargeted urine metabolite profiles were obtained. The complete procedure (Test) was repeated 1 week later (Retest) to assess repeatability. Metabolic effect parameters with regard to energy metabolism and urine metabolomics were similar for both the Test and Retest period, underlining comparable exercise load. Following exercise, intestinal permeability (1 h plasma lactulose-to-rhamnose ratio) and the serum interleukin-6, interleukin-10, fibroblast growth factor-21 and muscle creatine kinase concentrations were significantly increased compared with rest only during the first test and not when the test was repeated. Responses to strenuous exercise in well-trained young men, as indicated by intestinal markers and myokines, show adaptation in Test-Retest outcome. This might be attributable to a carry-over effect of the defense mechanisms triggered during the Test. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

The role of oxidative, inflammatory and neuroendocrinological systems during exercise stress in athletes: implications of antioxidant supplementation on physiological adaptation during intensified physical training.

PubMed

Slattery, Katie; Bentley, David; Coutts, Aaron J

2015-04-01

During periods of intensified physical training, reactive oxygen species (ROS) release may exceed the protective capacity of the antioxidant system and lead to dysregulation within the inflammatory and neuroendocrinological systems. Consequently, the efficacy of exogenous antioxidant supplementation to maintain the oxidative balance in states of exercise stress has been widely investigated. The aim of this review was to (1) collate the findings of prior research on the effect of intensive physical training on oxidant-antioxidant balance; (2) summarise the influence of antioxidant supplementation on the reduction-oxidation signalling pathways involved in physiological adaptation; and (3) provide a synopsis on the interactions between the oxidative, inflammatory and neuroendocrinological response to exercise stimuli. Based on prior research, it is evident that ROS are an underlying aetiology in the adaptive process; however, the impact of antioxidant supplementation on physiological adaptation remains unclear. Equivocal results have been reported on the impact of antioxidant supplementation on exercise-induced gene expression. Further research is required to establish whether the interference of antioxidant supplementation consistently observed in animal-based and in vivo research extends to a practical sports setting. Moreover, the varied results reported within the literature may be due to the hormetic response of oxidative, inflammatory and neuroendocrinological systems to an exercise stimulus. The collective findings suggest that intensified physical training places substantial stress on the body, which can manifest as an adaptive or maladaptive physiological response. Additional research is required to determine the efficacy of antioxidant supplementation to minimise exercise-stress during intensive training and promote an adaptive state.

Learning about stress: neural, endocrine and behavioral adaptations.

PubMed

McCarty, Richard

2016-09-01

In this review, nonassociative learning is advanced as an organizing principle to draw together findings from both sympathetic-adrenal medullary and hypothalamic-pituitary-adrenocortical (HPA) axis responses to chronic intermittent exposure to a variety of stressors. Studies of habituation, facilitation and sensitization of stress effector systems are reviewed and linked to an animal's prior experience with a given stressor, the intensity of the stressor and the appraisal by the animal of its ability to mobilize physiological systems to adapt to the stressor. Brain pathways that regulate physiological and behavioral responses to stress are discussed, especially in light of their regulation of nonassociative processes in chronic intermittent stress. These findings may have special relevance to various psychiatric diseases, including depression and post-traumatic stress disorder (PTSD).

Applied physiology of triathlon.

PubMed

O'Toole, M L; Douglas, P S

1995-04-01

The triathlon is a 3-event endurance sport in which athletes compete sequentially in swimming, cycling and running. The primary determinant of success is the ability to sustain a high rate of energy expenditure for prolonged periods of time. Exercise training-induced physiological adaptations in virtually all systems of the body allow the athlete to accomplish this. Aerobic capacity (measured as maximal oxygen uptake, VO2max), economy of motion (submaximal VO2) and fractional utilisation of maximal capacity (%VO2max) reflect the integrated responses of these physiological adaptations. Numerous studies have reported relatively high mean VO2max values for various groups of triathletes that are comparable to those reported for athletes in single-event endurance sports and clearly above those reported for untrained individuals. In shorter distance triathlons and in studies using recreational (rather than elite) triathletes, VO2max is related to performance in the corresponding event of the triathlon (e.g. tethered swimming VO2max with swim time). In longer events and with more elite triathletes, VO2max correlates less well with performance. The physiological adaptations that correspond to and facilitate improved VO2max occur centrally in the cardiovascular system, centred on increased maximal cardiac output, and peripherally in the metabolic systems, centred around increased arterio-venous O2 (a-v O2) difference. While a high VO2max in individuals is clearly of importance to triathlon performance, energy output must be sustained for long periods of time, making economy of motion also very important. Studies suggests that competitive swimmers have better swimming economy than triathletes. However, since many triathletes have previously been competitive swimmers this finding is questionable. The finding suggests that triathletes from nonswimming backgrounds would benefit from improving swimming technique rather than concentrating training workouts solely on distance. In cycling and running, comparison studies have not been done. Economy of motion in swimming, cycling and running have all been found to be correlated with comparable event performance. Training to improve swimming economy can be done without prior exercise, but training to improve swimming economy can be done without prior exercise, but training to improve cycling and running economy should take the multimode nature of a triathlon into consideration. That is, swimming should precede cycling economy training, and cycling should precede running economy training. Cardiovascular, metabolic and neuromuscular adaptations are the main physiological correlates of improved movement economy. Since exercise-induced stress on most physiological systems is based on relative, rather than absolute, exercise intensity, training and racing intensities are frequently quantified as a percentage of maximal capacity of %VO2max.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for -Gz Adaptation Observed with Wearable Biosensors During High Performance Jet Flight.

PubMed

Rice, G Merrill; Snider, Dallas; Moore, Jeffrey L; Lavan, J Timothy; Folga, Rich; VanBrunt, Thomas B

2016-12-01

Few studies have evaluated physiological responses to high acceleration forces during actual flight and to our knowledge no normative data has been acquired by technologies such as wearable biosensors during high performance jet aircraft operations. In-flight physiological data from an FDA cleared portable triaxial accelerometer and bio-sensor were observed from five active duty F-18 pilots of the Naval Flight Demonstration Squadron (Blue Angels). Of the five pilots, three were formation pilots who flew lower G profiles and two were solo pilots who flew higher G profiles. Physiological parameters monitored were heart rate, respiratory rate, temperature, caloric expenditure, and duration of exposure to levels of acceleration. Evaluated were 25 practice demonstration flights; 9 flights were excluded secondary to incomplete or inaccurate physiological data. We observed no significant bradycardia during a total of 189 maneuvers which met inclusion criteria for push-pull events (PPE) or isolated -Gz exposures. Further analysis of 73 PPE revealed an overall significant rise in HR following the PPE, where mean heart rate was 106 (95% CI, 100:112) at the beginning of the push and 129 (95% CI, 123:135) following the pull. A majority of the flights monitored provided reliable physiological data. Initial data suggests, contrary to currently held aeromedical doctrine, maneuvers such as the "push-pull" do not evoke vasovagal based bradycardic responses in aerobatic pilots. Possible explanations for these findings are sympathetic nervous system activation through adaptation and/or sustained isometric resistance from control inputs, both of which are areas of future research for our team.Rice GM, Snider D, Moore JL, Lavan JT, Folga R, VanBrunt TB. Evidence for -Gz adaptation observed with wearable biosensors during high performance jet flight. Aerosp Med Hum Perform. 2016; 87(12):996-1003.

Exploring physiological plasticity and local thermal adaptation in an intertidal crab along a latitudinal cline.

PubMed

Gaitán-Espitia, Juan Diego; Bacigalupe, Leonardo D; Opitz, Tania; Lagos, Nelson A; Osores, Sebastián; Lardies, Marco A

2017-08-01

Intertidal organisms have evolved physiological mechanisms that enable them to maintain performance and survive during periods of severe environmental stress with temperatures close to their tolerance limits. The level of these adaptive responses in thermal physiology can vary among populations of broadly distributed species depending on their particular environmental context and genetic backgrounds. Here we examined thermal performances and reaction norms for metabolic rate (MR) and heart rate (HR) of seven populations of the porcelanid crab Petrolisthes violaceus from markedly different thermal environments across the latitudinal gradient of ~3000km. Physiological responses of this intertidal crab under common-garden conditions suggest the absence of local thermal adaptation along the geographic gradient (i.e., lack of latitudinal compensation). Moreover, thermal physiological sensitivities and performances in response to increased temperatures evidenced the existence of some level of: i) metabolic rate control or depression during warm temperature exposures; and ii) homeostasis/canalization (i.e., absence or low levels of plasticity) in physiological traits that may reflect some sort of buffering mechanism in most of the populations. Nevertheless, our results indicate that elevated temperatures can reduce cardiac function but not metabolic rate in high latitude crabs. The lack of congruence between HR and MR supports the idea that energy metabolism in marine invertebrates cannot be inferred from HR and different conclusions regarding geographic differentiation in energy metabolism can be obtained from both physiological traits. Integrating thermal physiology and species range extent can contribute to a better understanding of the likely effects of climate change on natural populations of marine ectotherms. Copyright © 2017 Elsevier Ltd. All rights reserved.

A comparative evaluation of adaptive noise cancellation algorithms for minimizing motion artifacts in a forehead-mounted wearable pulse oximeter.

PubMed

Comtois, Gary; Mendelson, Yitzhak; Ramuka, Piyush

2007-01-01

Wearable physiological monitoring using a pulse oximeter would enable field medics to monitor multiple injuries simultaneously, thereby prioritizing medical intervention when resources are limited. However, a primary factor limiting the accuracy of pulse oximetry is poor signal-to-noise ratio since photoplethysmographic (PPG) signals, from which arterial oxygen saturation (SpO2) and heart rate (HR) measurements are derived, are compromised by movement artifacts. This study was undertaken to quantify SpO2 and HR errors induced by certain motion artifacts utilizing accelerometry-based adaptive noise cancellation (ANC). Since the fingers are generally more vulnerable to motion artifacts, measurements were performed using a custom forehead-mounted wearable pulse oximeter developed for real-time remote physiological monitoring and triage applications. This study revealed that processing motion-corrupted PPG signals by least mean squares (LMS) and recursive least squares (RLS) algorithms can be effective to reduce SpO2 and HR errors during jogging, but the degree of improvement depends on filter order. Although both algorithms produced similar improvements, implementing the adaptive LMS algorithm is advantageous since it requires significantly less operations.

Physiologic adaptation of man in space; Proceedings of the Seventh International Man in Space Symposium, Houston, TX, Feb. 10-13, 1986

NASA Technical Reports Server (NTRS)

Holland, Albert W. (Editor)

1987-01-01

Topics discussed in this volume include space motion sickness, cardiovascular adaptation, fluid shifts, extravehicular activity, general physiology, perception, vestibular response modifications, vestibular physiology, and pharmacology. Papers are presented on the clinical characterization and etiology of space motion sickness, ultrasound techniques in space medicine, fluid shifts in weightlessness, Space Shuttle inflight and postflight fluid shifts measured by leg volume changes, and the probability of oxygen toxicity in an 8-psi space suit. Consideration is also given to the metabolic and hormonal status of crewmembers in short-term space flights, adaptive changes in perception of body orientation and mental image rotation in microgravity, the effects of a visual-vestibular stimulus on the vestibulo-ocular reflex, rotation tests in the weightless phase of parabolic flight, and the mechanisms of antimotion sickness drugs.

Preclinical experimental stress studies: protocols, assessment and comparison.

PubMed

Bali, Anjana; Jaggi, Amteshwar Singh

2015-01-05

Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Preclinical models are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these models are also important for the development of novel pharmacological agents for stress management. The well described preclinical stress models include immobilization, restraint, electric foot shock and social isolation stress. Stress assessment in animals is done at the behavioral level using open field, social interaction, hole board test; at the biochemical level by measuring plasma corticosterone and ACTH; at the physiological level by measuring food intake, body weight, adrenal gland weight and gastric ulceration. Furthermore the comparison between different stressors including electric foot shock, immobilization and cold stressor is described in terms of intensity, hormonal release, protein changes in brain, adaptation and sleep pattern. This present review describes these preclinical stress protocols, and stress assessment at different levels. Copyright © 2014 Elsevier B.V. All rights reserved.

Nursing Approach Based on Roy Adaptation Model in a Patient Undergoing Breast Conserving Surgery for Breast Cancer.

PubMed

Ursavaş, Figen Erol; Karayurt, Özgül; İşeri, Özge

2014-07-01

The use of models in nursing provides nurses to focus on the role of nursing and its applications rather than medical practice. In addition, it helps patient care to be systematic, purposeful, controlled and effective. One of the commonly used models in nursing is Roy Adaptation Model. According to Roy adaptation model, the aim of nursing is to increase compliance and life expectancy. Roy Adaptation Model evaluates the patient in physiologic mode, self-concept mode, role function mode and interdependence mode aiming to provide holistic care. This article describes the use of Roy Adaptation Model in the care of a patient who has been diagnosed with breast cancer and had breast-conserving surgery. Patient data was evaluated in the four modes of Roy adaptation model (physiologic, self-concept, role function, and interdependence modes) and the nursing process was applied.

Amino acids as a source of organic nitrogen in Antarctic endolithic microbial communities

NASA Technical Reports Server (NTRS)

McDonald, G.; Sun, H.

2002-01-01

In the Antarctic Dry Valleys, cryptoendolithic microbial communities occur within porous sandstone rocks. Current understanding of the mechanisms of physiological adaptation of these communities to the harsh Antarctic environment is limited, because traditional methods of studying microbial physiology are very difficult to apply to organisms with extremely low levels of metabolic activity. In order to fully understand carbon and nitrogen cycling and nutrient uptake in cryptoendolithic communities, and the metabolic costs that the organisms incur in order to survive, it is necessary to employ molecular geochemical techniques such as amino acid analysis in addition to physiological methods.

Contrasting Physiological and Proteomic Adaptations to Iron and/or Copper Limitation in Two Strains of the Same Open Ocean Diatom Thalassiosira oceanica

NASA Astrophysics Data System (ADS)

Schuback, N.; Hippmann, A.; Maldonado, M. T.; Allen, A. E.; McCrow, J.; Foster, L. J.; Green, B. R.; Alami, M.

2016-02-01

Iron plays a significant role in controlling marine primary productivity. Despite that extremely low dissolved iron (Fe) concentrations are found in Fe-limited regions, some phytoplankton are able to survive and thrive. Two strains of the model oceanic diatom Thalassiosira oceanica, TO 1003 and TO 1005, have both been used in previous studies to characterize adaptations to iron limitation. These studies have shown that T. oceanica has lowered its Fe requirements and increased its Fe acquisition efficiency compared to coastal counterparts. Both strategies may impose a higher cellular copper (Cu) demand. However, the underlying biochemical adaptations in these oceanic diatoms remain unknown. Recently, the genome, as well as the first proteomic and transcriptomic analyses of T. oceanica 1005 grown under different Fe levels, were published. To further our understanding of the interplay between Fe- and Cu- physiology in open ocean diatoms, we examined an array of physiological responses to varying degrees of Fe-, Cu- and Fe/Cu co-limitation in both strains. We also determined the differential expression of proteins using stable isotope labeling and LC-MS/MS proteomic analysis. The two strains, TO 1003 and TO 1005, need markedly different metal concentrations in the media. TO1003 requires 30% less Cu to sustain its optimal growth and less than 1/10th of the minimum Cu that is needed by TO 1005 to survive. In contrast, TO 1005 is able to grow with less Fe available in the media. The physiological and proteomic responses of these two strains when acclimated to low Fe and/or Cu concentrations will be presented. The evolutionary implications will be discussed.

Bioarchaeology of adaptation to a marginal environment in bronze age Western China.

PubMed

Berger, Elizabeth; Wang, Hui

2017-07-08

This study examines human adaptation to the 4000 BP climate change event, which is said to have increased the marginality of Inner Asian environments. We propose to define "marginal" environments not in relation to a specific economic activity (e.g., agriculture), but in relation to whether humans living there are physiologically stressed. Three sites in the Hexi Corridor of Gansu were studied, one from the early and two from the late Bronze Age (N = 125). The study includes three indicators of physiological stress: linear enamel hypoplasias (LEH); tibial periosteal lesions; and fertility. The early and late Bronze Age groups were compared to examine whether human physiological stress increased. The percent of individuals with LEH declined dramatically, indicating fewer growth disruptions. Tibial periosteal reactions also changed, from mostly active to mostly healing at the time of death, indicating that frailty declined. Fertility, which is sensitive to changes in population health and resource availability, did not change significantly. Counter to the dominant narrative of environmental deterioration and subsistence system collapse, the Bronze Age residents of the Hexi Corridor show no skeletal evidence that they suffered from resource shortages or struggled to adapt in the fluctuating climate that pertained after the 4000 BP climate event. In fact, this study found that people suffered from less frailty and fewer growth disruptions after the unstable climate had persisted for some time. Therefore, in human biological terms, the Hexi Corridor did not become more marginal for human habitation during the Bronze Age. © 2017 Wiley Periodicals, Inc.

Predicting organismal vulnerability to climate warming: roles of behaviour, physiology and adaptation

PubMed Central

Huey, Raymond B.; Kearney, Michael R.; Krockenberger, Andrew; Holtum, Joseph A. M.; Jess, Mellissa; Williams, Stephen E.

2012-01-01

A recently developed integrative framework proposes that the vulnerability of a species to environmental change depends on the species' exposure and sensitivity to environmental change, its resilience to perturbations and its potential to adapt to change. These vulnerability criteria require behavioural, physiological and genetic data. With this information in hand, biologists can predict organisms most at risk from environmental change. Biologists and managers can then target organisms and habitats most at risk. Unfortunately, the required data (e.g. optimal physiological temperatures) are rarely available. Here, we evaluate the reliability of potential proxies (e.g. critical temperatures) that are often available for some groups. Several proxies for ectotherms are promising, but analogous ones for endotherms are lacking. We also develop a simple graphical model of how behavioural thermoregulation, acclimation and adaptation may interact to influence vulnerability over time. After considering this model together with the proxies available for physiological sensitivity to climate change, we conclude that ectotherms sharing vulnerability traits seem concentrated in lowland tropical forests. Their vulnerability may be exacerbated by negative biotic interactions. Whether tropical forest (or other) species can adapt to warming environments is unclear, as genetic and selective data are scant. Nevertheless, the prospects for tropical forest ectotherms appear grim. PMID:22566674

The Adaptive Brain: Glenn Hatton and the Supraoptic Nucleus

PubMed Central

Leng, G.; Moos, F. C.; Armstrong, W. E.

2017-01-01

In December 2009, Glenn Hatton died, and neuroendocrinology lost a pioneer who had done much to forge our present understanding of the hypothalamus and whose productivity had not faded with the passing years. Glenn, an expert in both functional morphology and electrophysiology, was driven by a will to understand the significance of his observations in the context of the living, behaving organism. He also had the wit to generate bold and challenging hypotheses, the wherewithal to expose them to critical and elegant experimental testing, and a way with words that gave his papers and lectures clarity and eloquence. The hypothalamo-neurohypophysial system offered a host of opportunities for understanding how physiological functions are fulfilled by the electrical activity of neurones, how neuronal behaviour changes with changing physiological states, and how morphological changes contribute to the physiological response. In the vision that Glenn developed over 35 years, the neuroendocrine brain is as dynamic in structure as it is adaptable in function. Its adaptability is reflected not only by mere synaptic plasticity, but also by changes in neuronal morphology and in the morphology of the glial cells. Astrocytes, in Glenn’s view, were intimate partners of the neurones, partners with an essential role in adaptation to changing physiological demands. PMID:20298459

The Big Breakfast Study: Chrono-nutrition influence on energy expenditure and bodyweight.

PubMed

Ruddick-Collins, L C; Johnston, J D; Morgan, P J; Johnstone, A M

2018-06-01

A growing body of evidence highlights the importance of the biological clock as a modulator of energy balance and metabolism. Recent studies in humans have shown that ingested calories are apparently utilised more efficiently in the morning than in the evening and this is manifest through improved weight loss, even under iso-energetic calorie intake. The mechanisms behind this enhanced morning energy metabolism are not yet clear, although it may result from behavioural adaptations or circadian driven variations in physiology and energy metabolism. A major objective of the newly funded Big Breakfast Study therefore is to investigate the mechanistic basis of this amplified morning thermogenesis leading to enhanced weight loss, by exploring behavioural and physiological adaptations in energy expenditure alongside the underlying circadian biology. This report briefly discusses the current research linking meal timing, circadian rhythms and metabolism; highlights the research gaps; and provides an overview of the studies being undertaken as part of the Medical Research Council-funded Big Breakfast Study .

Physiological Studies and Pest Control

ERIC Educational Resources Information Center

Philogene, Bernard J. R.

1972-01-01

In the light of new knowledge about insecticides, future research should be conducted by plant and insect physiologists together. Plant physiologists should explain what characteristics in plants attract insects and insect physiologists should study adaptive patterns of insects and combine their knowledge to control insects. (PS)

Physiological adaptations to interval training and the role of exercise intensity.

PubMed

MacInnis, Martin J; Gibala, Martin J

2017-05-01

Interval exercise typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery. A common classification scheme subdivides this method into high-intensity interval training (HIIT; 'near maximal' efforts) and sprint interval training (SIT; 'supramaximal' efforts). Both forms of interval training induce the classic physiological adaptations characteristic of moderate-intensity continuous training (MICT) such as increased aerobic capacity (V̇O2 max ) and mitochondrial content. This brief review considers the role of exercise intensity in mediating physiological adaptations to training, with a focus on the capacity for aerobic energy metabolism. With respect to skeletal muscle adaptations, cellular stress and the resultant metabolic signals for mitochondrial biogenesis depend largely on exercise intensity, with limited work suggesting that increases in mitochondrial content are superior after HIIT compared to MICT, at least when matched-work comparisons are made within the same individual. It is well established that SIT increases mitochondrial content to a similar extent to MICT despite a reduced exercise volume. At the whole-body level, V̇O2 max is generally increased more by HIIT than MICT for a given training volume, whereas SIT and MICT similarly improve V̇O2 max despite differences in training volume. There is less evidence available regarding the role of exercise intensity in mediating changes in skeletal muscle capillary density, maximum stroke volume and cardiac output, and blood volume. Furthermore, the interactions between intensity and duration and frequency have not been thoroughly explored. While interval training is clearly a potent stimulus for physiological remodelling in humans, the integrative response to this type of exercise warrants further attention, especially in comparison to traditional endurance training. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Physiological response and productivity of safflower lines under water deficit and rehydration.

PubMed

Bortolheiro, Fernanda P A P; Silva, Marcelo A

2017-01-01

Water deficit is one of the major stresses affecting plant growth and productivity worldwide. Plants induce various morphological, physiological, biochemical and molecular changes to adapt to the changing environment. Safflower (Carthamus tinctorius L.), a potential oil producer, is highly adaptable to various environmental conditions, such as lack of rainfall and temperatures. The objective of this work was to study the physiological and production characteristics of six safflower lines in response to water deficit followed by rehydration. The experiment was conducted in a protected environment and consisted of 30 days of water deficit followed by 18 days of rehydration. A differential response in terms of photosynthetic pigments, electrolyte leakage, water potential, relative water content, grain yield, oil content, oil yield and water use efficiency was observed in the six lines under water stress. Lines IMA 04, IMA 10, IMA 14 showed physiological characteristics of drought tolerance, with IMA 14 and IMA 16 being the most productive after water deficit. IMA 02 and IMA 21 lines displayed intermediate characteristics of drought tolerance. It was concluded that the lines responded differently to water deficit stress, showing considerable genetic variation and influence to the environment.

Probiotics normalize the gut-brain-microbiota axis in immunodeficient mice.

PubMed

Smith, Carli J; Emge, Jacob R; Berzins, Katrina; Lung, Lydia; Khamishon, Rebecca; Shah, Paarth; Rodrigues, David M; Sousa, Andrew J; Reardon, Colin; Sherman, Philip M; Barrett, Kim E; Gareau, Mélanie G

2014-10-15

The gut-brain-microbiota axis is increasingly recognized as an important regulator of intestinal physiology. Exposure to psychological stress causes activation of the hypothalamic-pituitary-adrenal (HPA) axis and causes altered intestinal barrier function, intestinal dysbiosis, and behavioral changes. The primary aim of this study was to determine whether the effects of psychological stress on intestinal physiology and behavior, including anxiety and memory, are mediated by the adaptive immune system. Furthermore, we wanted to determine whether treatment with probiotics would normalize these effects. Here we demonstrate that B and T cell-deficient Rag1(-/-) mice displayed altered baseline behaviors, including memory and anxiety, accompanied by an overactive HPA axis, increased intestinal secretory state, dysbiosis, and decreased hippocampal c-Fos expression. Both local (intestinal physiology and microbiota) and central (behavioral and hippocampal c-Fos) changes were normalized by pretreatment with probiotics, indicating an overall benefit on health conferred by changes in the microbiota, independent of lymphocytes. Taken together, these findings indicate a role for adaptive immune cells in maintaining normal intestinal and brain health in mice and show that probiotics can overcome this immune-mediated deficit in the gut-brain-microbiota axis. Copyright © 2014 the American Physiological Society.

Parasite-altered feeding behavior in insects: integrating functional and mechanistic research frontiers.

PubMed

Bernardo, Melissa A; Singer, Michael S

2017-08-15

Research on parasite-altered feeding behavior in insects is contributing to an emerging literature that considers possible adaptive consequences of altered feeding behavior for the host or the parasite. Several recent ecoimmunological studies show that insects can adaptively alter their foraging behavior in response to parasitism. Another body of recent work shows that infection by parasites can change the behavior of insect hosts to benefit the parasite; manipulations of host feeding behavior may be part of this phenomenon. Here, we address both the functional and the underlying physiological frontiers of parasite-altered feeding behavior in order to spur research that better integrates the two. Functional categories of parasite-altered behavior that are adaptive for the host include prophylaxis, therapy and compensation, while host manipulation is adaptive for the parasite. To better understand and distinguish prophylaxis, therapy and compensation, further study of physiological feedbacks affecting host sensory systems is especially needed. For host manipulation in particular, research on mechanisms by which parasites control host feedbacks will be important to integrate with functional approaches. We see this integration as critical to advancing the field of parasite-altered feeding behavior, which may be common in insects and consequential for human and environmental health. © 2017. Published by The Company of Biologists Ltd.

Physiological and transcriptomic analyses reveal mechanistic insight into the adaption of marine Bacillus subtilis C01 to alumina nanoparticles.

PubMed

Mu, Dashuai; Yu, Xiuxia; Xu, Zhenxing; Du, Zongjun; Chen, Guanjun

2016-07-21

An increasing number of studies have investigated the effects of nanoparticles (NPs) on microbial systems; however, few existing reports have focused on the defense mechanisms of bacteria against NPs. Whether secondary metabolism biosynthesis is a response to NP stress and contributes to the adaption of bacteria to NPs is unclear. Here, a significant induction in the surfactin production and biofilm formation were detected by adding Al2O3 NPs to the B. subtilis fermentation broth. Physiological analysis showed that Al2O3 NP stress could also affect the cell and colony morphogenesis and inhibit the motility and sporulation. Exogenously adding commercial surfactin restored the swarming motility. Additionally, a suite of toxicity assays analyzing membrane damage, cellular ROS generation, electron transport activity and membrane potential was used to determine the molecular mechanisms of toxicity of Al2O3 NPs. Furthermore, whole transcriptomic analysis was used to elucidate the mechanisms of B. subtilis adaption to Al2O3 NPs. These results revealed several mechanisms by which marine B. subtilis C01 adapt to Al2O3 NPs. Additionally, this study broadens the applications of nanomaterials and describes the important effects on secondary metabolism and multicellularity regulation by using Al2O3 NPs or other nano-products.

Adaptation to prolonged bedrest in man: A compendium of research. [bibliographies on clinical medicine and human pathology

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Greenleaf, C. J.; Vanderveer, D.; Dorchak, K. J.

1976-01-01

A compilation of major studies that describe the clinical observations and elucidate the physiological mechanisms of the adaptive process of man undergoing prolonged bed rest is presented. Additional studies are included that provide background information in the form of reviews or summaries of the process. Wherever possible a detailed annotation is provided under the subheadings: (1) purpose, (2) procedure and methods, (3) results, and (4) conclusions. Additional references are provided in a selected bibliography.

Adaptation to Life in the High Andes: Nocturnal Oxyhemoglobin Saturation in Early Development.

PubMed

Hill, Catherine Mary; Baya, Ana; Gavlak, Johanna; Carroll, Annette; Heathcote, Kate; Dimitriou, Dagmara; L'Esperance, Veline; Webster, Rebecca; Holloway, John; Virues-Ortega, Javier; Kirkham, Fenella Jane; Bucks, Romola Starr; Hogan, Alexandra Marie

2016-05-01

Physiological adaptation to high altitude hypoxia may be impaired in Andeans with significant European ancestry. The respiratory 'burden' of sleep may challenge adaptation, leading to relative nocturnal hypoxia. Developmental aspects of sleep-related breathing in high-altitude native children have not previously been reported. We aimed to determine the influence of development on diurnal-nocturnal oxyhemoglobin differences in children living at high altitude. This was a cross-sectional, observational study. Seventy-five healthy Bolivian children aged 6 mo to 17 y, native to low altitude (500 m), moderate high altitude (2,500 m), and high altitude (3,700 m) were recruited. Daytime resting pulse oximetry was compared to overnight recordings using Masimo radical oximeters. Genetic ancestry was determined from DNA samples. Children had mixed European/Amerindian ancestry, with no significant differences between altitudes. Sixty-two participants had ≥ 5 h of nocturnal, artifact-free data. As predicted, diurnal mean oxyhemoglobin saturation decreased across altitudes (infants and children, both P < 0.001), with lowest diurnal values at high altitude in infants. At high altitude, there was a greater drop in nocturnal mean oxyhemoglobin saturation (infants, P < 0.001; children, P = 0.039) and an increase in variability (all P ≤ 0.001) compared to low altitude. Importantly, diurnal to nocturnal altitude differences diminished (P = 0.036), from infancy to childhood, with no further change during adolescence. Physiological adaptation to high-altitude living in native Andeans is unlikely to compensate for the significant differences we observed between diurnal and nocturnal oxyhemoglobin saturation, most marked in infancy. This vulnerability to sleep-related hypoxia in early childhood has potential lifespan implications. Future studies should characterize the sleep- related respiratory physiology underpinning our observations. © 2016 Associated Professional Sleep Societies, LLC.

Epigenomics and human adaptation to high altitude.

PubMed

Julian, Colleen G

2017-11-01

Over the past decade, major technological and analytical advancements have propelled efforts toward identifying the molecular mechanisms that govern human adaptation to high altitude. Despite remarkable progress with respect to the identification of adaptive genomic signals that are strongly associated with the "hypoxia-tolerant" physiological characteristics of high-altitude populations, many questions regarding the fundamental biological processes underlying human adaptation remain unanswered. Vital to address these enduring questions will be determining the role of epigenetic processes, or non-sequence-based features of the genome, that are not only critical for the regulation of transcriptional responses to hypoxia but heritable across generations. This review proposes that epigenomic processes are involved in shaping patterns of adaptation to high altitude by influencing adaptive potential and phenotypic variability under conditions of limited oxygen supply. Improved understanding of the interaction between genetic, epigenetic, and environmental factors holds great promise to provide deeper insight into the mechanisms underlying human adaptive potential, and clarify its implications for biomedical research. Copyright © 2017 the American Physiological Society.

Molecular Mechanisms Underlying Cardiac Adaptation to Exercise

PubMed Central

Vega, Rick B.; Konhilas, John P.; Kelly, Daniel P.; Leinwand, Leslie A.

2017-01-01

Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations. PMID:28467921

Mitochondrial adaptations to physiological vs. pathological cardiac hypertrophy

PubMed Central

Abel, E. Dale; Doenst, Torsten

2011-01-01

Cardiac hypertrophy is a stereotypic response of the heart to increased workload. The nature of the workload increase may vary depending on the stimulus (repetitive, chronic, pressure, or volume overload). If the heart fully adapts to the new loading condition, the hypertrophic response is considered physiological. If the hypertrophic response is associated with the ultimate development of contractile dysfunction and heart failure, the response is considered pathological. Although divergent signalling mechanisms may lead to these distinct patterns of hypertrophy, there is some overlap. Given the close relationship between workload and energy demand, any form of cardiac hypertrophy will impact the energy generation by mitochondria, which are the key organelles for cellular ATP production. Significant changes in the expression of nuclear and mitochondrially encoded transcripts that impact mitochondrial function as well as altered mitochondrial proteome composition and mitochondrial energetics have been described in various forms of cardiac hypertrophy. Here, we review mitochondrial alterations in pathological and physiological hypertrophy. We suggest that mitochondrial adaptations to pathological and physiological hypertrophy are distinct, and we shall review potential mechanisms that might account for these differences. PMID:21257612

Architecture of thermal adaptation in an Exiguobacterium sibiricum strain isolated from 3 million year old permafrost: A genome and transcriptome approach

PubMed Central

Rodrigues, Debora F; Ivanova, Natalia; He, Zhili; Huebner, Marianne; Zhou, Jizhong; Tiedje, James M

2008-01-01

Background Many microorganisms have a wide temperature growth range and versatility to tolerate large thermal fluctuations in diverse environments, however not many have been fully explored over their entire growth temperature range through a holistic view of its physiology, genome, and transcriptome. We used Exiguobacterium sibiricum strain 255-15, a psychrotrophic bacterium from 3 million year old Siberian permafrost that grows from -5°C to 39°C to study its thermal adaptation. Results The E. sibiricum genome has one chromosome and two small plasmids with a total of 3,015 protein-encoding genes (CDS), and a GC content of 47.7%. The genome and transcriptome analysis along with the organism's known physiology was used to better understand its thermal adaptation. A total of 27%, 3.2%, and 5.2% of E. sibiricum CDS spotted on the DNA microarray detected differentially expressed genes in cells grown at -2.5°C, 10°C, and 39°C, respectively, when compared to cells grown at 28°C. The hypothetical and unknown genes represented 10.6%, 0.89%, and 2.3% of the CDS differentially expressed when grown at -2.5°C, 10°C, and 39°C versus 28°C, respectively. Conclusion The results show that E. sibiricum is constitutively adapted to cold temperatures stressful to mesophiles since little differential gene expression was observed between 4°C and 28°C, but at the extremities of its Arrhenius growth profile, namely -2.5°C and 39°C, several physiological and metabolic adaptations associated with stress responses were observed. PMID:19019206

Design and conduct of Caudwell Xtreme Everest: an observational cohort study of variation in human adaptation to progressive environmental hypoxia

PubMed Central

2010-01-01

Background The physiological responses to hypoxaemia and cellular hypoxia are poorly understood, and inter-individual differences in performance at altitude and outcome in critical illness remain unexplained. We propose a model for exploring adaptation to hypoxia in the critically ill: the study of healthy humans, progressively exposed to environmental hypobaric hypoxia (EHH). The aim of this study was to describe the spectrum of adaptive responses in humans exposed to graded EHH and identify factors (physiological and genetic) associated with inter-individual variation in these responses. Methods Design Observational cohort study of progressive incremental exposure to EHH. Setting University human physiology laboratory in London, UK (75 m) and 7 field laboratories in Nepal at 1300 m, 3500 m, 4250 m, 5300 m, 6400 m, 7950 m and 8400 m. Participants 198 healthy volunteers and 24 investigators trekking to Everest Base Camp (EBC) (5300 m). A subgroup of 14 investigators studied at altitudes up to 8400 m on Everest. Main outcome measures Exercise capacity, exercise efficiency and economy, brain and muscle Near Infrared Spectroscopy, plasma biomarkers (including markers of inflammation), allele frequencies of known or suspected hypoxia responsive genes, spirometry, neurocognitive testing, retinal imaging, pupilometry. In nested subgroups: microcirculatory imaging, muscle biopsies with proteomic and transcriptomic tissue analysis, continuous cardiac output measurement, arterial blood gas measurement, trans-cranial Doppler, gastrointestinal tonometry, thromboelastography and ocular saccadometry. Results Of 198 healthy volunteers leaving Kathmandu, 190 reached EBC (5300 m). All 24 investigators reached EBC. The completion rate for planned testing was more than 99% in the investigator group and more than 95% in the trekkers. Unique measurements were safely performed at extreme altitude, including the highest (altitude) field measurements of exercise capacity, cerebral blood flow velocity and microvascular blood flow at 7950 m and arterial blood gas measurement at 8400 m. Conclusions This study demonstrates the feasibility and safety of conducting a large healthy volunteer cohort study of human adaptation to hypoxia in this difficult environment. Systematic measurements of a large set of variables were achieved in 222 subjects and at altitudes up to 8400 m. The resulting dataset is a unique resource for the study of genotype:phenotype interactions in relation to hypoxic adaptation. PMID:20964858

A molecular mechanism of adaptation in an estuarine copepod

NASA Astrophysics Data System (ADS)

Bradley, Brian P.; Lane, Maxine A.; Gonzalez, Carole M.

The estuarine copepod Eurytemora affinis (Poppe) has been shown to adapt better at the individual (physiological) and population (genetic) level to rapidly cycling environments than to slowly cycling temperatures. In addition, female copepods are physiologically more flexible than males. Three questions arise from these observations. Why is the geographical and seasonal distribution of Eurytemora in estuaries so limited? Why is the genetic variance so high in an organism which is so physiologically flexible? And does the difference between sexes help to explain the maintenance of genetic variance? A mechanism of adaptation which may allow further examination of these questions is the increased synthesis of stress proteins, first identified as heat shock proteins (HSP). The HSPs in the copepod Eurytemora affinis are quantitatively and qualitatively related to stress. Temperature and osmotic stress, for example, induce different sets of proteins. Thus, better understanding the phenomenon may be useful in marine ecology.

Cold-adapted tubulins in the glacier ice worm, Mesenchytraeus solifugus.

PubMed

Tartaglia, Lawrence J; Shain, Daniel H

2008-11-01

Glacier ice worms, Mesenchytraeus solifugus and related species, are the only known annelids that survive obligately in glacier ice and snow. One fundamental component of cold temperature adaptation is the ability to polymerize tubulin, which typically depolymerizes at low physiological temperatures (e.g., <10 degrees C) in most temperate species. In this study, we isolated two alpha-tubulin (Msalpha1, Msalpha2) and two beta-tubulin (Msbeta1, Msbeta2) subunits from an ice worm cDNA library, and compared their predicted amino acid sequences with homologues from other cold-adapted organisms (e.g., Antarctic fish, ciliate) in an effort to identify species-specific amino acid substitutions that contribute to cold temperature-dependent tubulin polymerization. Our comparisons and predicted protein structures suggest that ice worm-specific amino acid substitutions stabilize lateral contact associations, particularly between beta-tubulin protofilaments, but these substitutions occur at different positions in comparison with other cold-adapted tubulins. The ice worm tubulin gene family appears relatively small, comprising one primary alpha- and one primary beta-tubulin monomers, though minor isoforms and pseudogenes were identified. Our analyses suggest that variation occurs in the strategies (i.e., species-specific amino acid substitutions, gene number) by which cold-adapted taxa have evolved the ability to polymerize tubulin at low physiological temperatures.

Adaptive dimensions of health research among indigenous Siberians.

PubMed

Snodgrass, J Josh; Sorensen, Mark V; Tarskaia, Larissa A; Leonard, William R

2007-01-01

Present evidence suggests that modern humans were the first hominid species to successfully colonize high-latitude environments (> or =55 degrees N). Given evidence for a recent (<200,000 years) lower latitude naissance of modern humans, the global dispersal and successful settlement of arctic and subarctic regions represent an unprecedented adaptive shift. This adaptive shift, which included cultural, behavioral, and biological dimensions, allowed human populations to cope with the myriad environmental stressors encountered in circumpolar regions. Although unique morphological and physiological adaptations among contemporary northern residents have been recognized for decades, human biologists are only now beginning to consider whether biological adaptations to regional environmental conditions influence health changes associated with economic modernization and lifestyle change. Recent studies have documented basal metabolic rates (BMRs) among indigenous Siberian populations that are systematically elevated compared to lower latitude groups; this metabolic elevation apparently is a physiological adaptation to cold stress experienced in the circumpolar environment. Important health implications of metabolic adaptation are suggested by research with the Yakut (Sakha), Evenki, and Buriat of Siberia. BMR is significantly positively correlated with blood pressure, independently of body size, body composition, and various potentially confounding variables (e.g., age and smoking). Further, this research has documented a significant negative association between BMR and LDL cholesterol, which remains after controlling for potential confounders; this suggests that high metabolic turnover among indigenous Siberians has a protective effect with regard to plasma lipid levels. These results underscore the importance of incorporating an evolutionary approach into health research among northern populations.

[Clinical and physiological rationale for use of clonidine with articaine and adrenaline for local anesthesia in pediatric dentistry].

PubMed

Mel'nikova, A V; Shugaĭlov, I A

2014-01-01

The study evaluated the effect of local anesthesia with articaine in different combinations with epinephrine and clonidine (articaine (4%) + epinephrine (1:200 000), articaine (4%) + clonidine (1:100 000), articaine (4%) + epinephrine (1:200 000) + clonidine (1:100 000), articaine (4%) + epinephrine (1:400 000) + clonidine (1:100 000)), on a number of physiological parameters in pediatric dental practice that characterize cardiovascular system, patient's degree of adaptation to a stressful situation and efficacy of analgesia. It is shown that in terms of impact on the cardiovascular system and stress adaptation indicators anesthesia including combination of epinephrine (1: 200 000) and clonidine (1: 100 000) in the anesthetic solution is the safest. Furthermore, this method ensures the most appropriate analgesic effect.

Salinity Tolerance Mechanism of Economic Halophytes From Physiological to Molecular Hierarchy for Improving Food Quality

PubMed Central

Xu, Chongzhi; Tang, Xiaoli; Shao, Hongbo; Wang, Hongyan

2016-01-01

Soil salinity is becoming the key constraints factor to agricultural production. Therefore, the plant especially the crops possessing capacities of salt tolerance will be of great economic significance. The adaptation or tolerance of plant to salinity stress involves a series of physiological, metabolic and molecular mechanisms. Halophytes are the kind of organisms which acquire special salt tolerance mechanisms to respond to the salt tress and ensure normal growth and development under saline conditions in their lengthy evolutionary adaptation, so understanding how halophytes respond to salinity stress will provide us with methods and tactics to foster and develop salt resistant varieties of crops. The strategies in physiological and molecular level adopted by halophytes are various including the changes in photosynthetic and transpiration rate, the sequestration of Na+ to extracellular or vacuole, the regulation of stomata aperture and stomatal density, the accumulation and synthesis of the phytohormones as well as the relevant gene expression underlying these physiological traits, such as the stress signal transduction, the regulation of the transcription factors, the activation and expression of the transporter genes, the activation or inhibition of the synthetases and so on. This review focuses on the research advances of the regulating mechanisms in halophytes from physiological to molecular, which render the halophytes tolerance and adaption to salinity stress. PMID:27252587

A viewpoint on considering physiological principles to study stress resistance and resilience with aging.

PubMed

Miller, Benjamin F; Seals, Douglas R; Hamilton, Karyn L

2017-09-01

Adaptation to stress is identified as one of the seven pillars of aging research. Our viewpoint discusses the importance of the distinction between stress resistance and resilience, highlights how integration of physiological principles is critical for further understanding in vivo stress resistance and resilience, and advocates for the use of early warning signs to prevent a tipping point in stress resistance and resilience. Copyright © 2017 Elsevier B.V. All rights reserved.

Concurrent exercise training: do opposites distract?

PubMed

Coffey, Vernon G; Hawley, John A

2017-05-01

Specificity is a core principle of exercise training to promote the desired adaptations for maximising athletic performance. The principle of specificity of adaptation is underpinned by the volume, intensity, frequency and mode of contractile activity and is most evident when contrasting the divergent phenotypes that result after undertaking either prolonged endurance or resistance training. The molecular profiles that generate the adaptive response to different exercise modes have undergone intense scientific scrutiny. Given divergent exercise induces similar signalling and gene expression profiles in skeletal muscle of untrained or recreationally active individuals, what is currently unclear is how the specificity of the molecular response is modified by prior training history. The time course of adaptation and when 'phenotype specificity' occurs has important implications for exercise prescription. This context is essential when attempting to concomitantly develop resistance to fatigue (through endurance-based exercise) and increased muscle mass (through resistance-based exercise), typically termed 'concurrent training'. Chronic training studies provide robust evidence that endurance exercise can attenuate muscle hypertrophy and strength but the mechanistic underpinning of this 'interference' effect with concurrent training is unknown. Moreover, despite the potential for several key regulators of muscle metabolism to explain an incompatibility in adaptation between endurance and resistance exercise, it now seems likely that multiple integrated, rather than isolated, effectors or processes generate the interference effect. Here we review studies of the molecular responses in skeletal muscle and evidence for the interference effect with concurrent training within the context of the specificity of training adaptation. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Behavioural and physiological adaptations to low-temperature environments in the common frog, Rana temporaria.

PubMed

Muir, Anna P; Biek, Roman; Mable, Barbara K

2014-05-23

Extreme environments can impose strong ecological and evolutionary pressures at a local level. Ectotherms are particularly sensitive to low-temperature environments, which can result in a reduced activity period, slowed physiological processes and increased exposure to sub-zero temperatures. The aim of this study was to assess the behavioural and physiological responses that facilitate survival in low-temperature environments. In particular, we asked: 1) do high-altitude common frog (Rana temporaria) adults extend the time available for larval growth by breeding at lower temperatures than low-altitude individuals?; and 2) do tadpoles sampled from high-altitude sites differ physiologically from those from low-altitude sites, in terms of routine metabolic rate (RMR) and freeze tolerance? Breeding date was assessed as the first day of spawn observation and local temperature recorded for five, paired high- and low-altitude R. temporaria breeding sites in Scotland. Spawn was collected and tadpoles raised in a common laboratory environment, where RMR was measured as oxygen consumed using a closed respiratory tube system. Freeze tolerance was measured as survival following slow cooling to the point when all container water had frozen. We found that breeding did not occur below 5°C at any site and there was no significant relationship between breeding temperature and altitude, leading to a delay in spawning of five days for every 100 m increase in altitude. The relationship between altitude and RMR varied by mountain but was lower for individuals sampled from high- than low-altitude sites within the three mountains with the highest high-altitude sites (≥900 m). In contrast, individuals sampled from low-altitudes survived freezing significantly better than those from high-altitudes, across all mountains. Our results suggest that adults at high-altitude do not show behavioural adaptations in terms of breeding at lower temperatures. However, tadpoles appear to have the potential to adapt physiologically to surviving at high-altitude via reduced RMR but without an increase in freeze tolerance. Therefore, survival at high-altitude may be facilitated by physiological mechanisms that permit faster growth rates, allowing completion of larval development within a shorter time period, alleviating the need for adaptations that extend the time available for larval growth.

Exploring the genetic basis of adaptation to high elevations in reptiles: a comparative transcriptome analysis of two toad-headed agamas (genus Phrynocephalus).

PubMed

Yang, Weizhao; Qi, Yin; Fu, Jinzhong

2014-01-01

High elevation adaptation offers an excellent study system to understand the genetic basis of adaptive evolution. We acquired transcriptome sequences of two closely related lizards, Phrynocephalus przewalskii from low elevations and P. vlangalii from high elevations. Within a phylogenetic framework, we compared their genomic data along with green anole, chicken and Chinese softshell turtle, and identified candidate genes and functional categories that are potentially linked to adaptation to high elevation environments. More than 100 million sequence reads were generated for each species via Illumina sequencing. A de novo assembly produced 70,919 and 62,118 transcripts for P. przewalskii and P. vlangalii, respectively. Based on a well-established reptile phylogeny, we detected 143 positively selected genes (PSGs) along the P. vlangalii lineage from the 7,012 putative orthologs using a branch-site model. Furthermore, ten GO categories and one KEGG pathway that are over-represented by PSGs were recognized. In addition, 58 GO categories were revealed to have elevated evolutionary rates along the P. vlangalii lineage relative to P. przewalskii. These functional analyses further filter out PSGs that are most likely involved in the adaptation process to high elevations. Among them, ADAM17, MD, and HSP90B1 likely contributed to response to hypoxia, and POLK likely contributed to DNA repair. Many other candidate genes involved in gene expression and metabolism were also identified. Genome-wide scan for candidate genes may serve as the first step to explore the genetic basis of high elevation adaptation. Detailed comparative study and functional verification are needed to solidify any conclusions. High elevation adaptation requires coordinated changes in multiple genes that involve various physiological and biochemical pathways; we hope that our genetic studies will provide useful directions for future physiological or molecular studies in reptiles as well as other poikilothermic species.

Exploring the Genetic Basis of Adaptation to High Elevations in Reptiles: A Comparative Transcriptome Analysis of Two Toad-Headed Agamas (Genus Phrynocephalus)

PubMed Central

Yang, Weizhao; Qi, Yin; Fu, Jinzhong

2014-01-01

High elevation adaptation offers an excellent study system to understand the genetic basis of adaptive evolution. We acquired transcriptome sequences of two closely related lizards, Phrynocephalus przewalskii from low elevations and P. vlangalii from high elevations. Within a phylogenetic framework, we compared their genomic data along with green anole, chicken and Chinese softshell turtle, and identified candidate genes and functional categories that are potentially linked to adaptation to high elevation environments. More than 100 million sequence reads were generated for each species via Illumina sequencing. A de novo assembly produced 70,919 and 62,118 transcripts for P. przewalskii and P. vlangalii, respectively. Based on a well-established reptile phylogeny, we detected 143 positively selected genes (PSGs) along the P. vlangalii lineage from the 7,012 putative orthologs using a branch-site model. Furthermore, ten GO categories and one KEGG pathway that are over-represented by PSGs were recognized. In addition, 58 GO categories were revealed to have elevated evolutionary rates along the P. vlangalii lineage relative to P. przewalskii. These functional analyses further filter out PSGs that are most likely involved in the adaptation process to high elevations. Among them, ADAM17, MD, and HSP90B1 likely contributed to response to hypoxia, and POLK likely contributed to DNA repair. Many other candidate genes involved in gene expression and metabolism were also identified. Genome-wide scan for candidate genes may serve as the first step to explore the genetic basis of high elevation adaptation. Detailed comparative study and functional verification are needed to solidify any conclusions. High elevation adaptation requires coordinated changes in multiple genes that involve various physiological and biochemical pathways; we hope that our genetic studies will provide useful directions for future physiological or molecular studies in reptiles as well as other poikilothermic species. PMID:25386640

Tissue physiological metabolic adaptability in young and old leaves of reed (Phragmites communis) in Songnen grassland.

PubMed

Guo, Rui; Bai, Zhenzi; Zhou, Ji; Zhong, XiuLi; Gu, FengXue; Liu, Qi; Li, HaoRu

2018-07-01

Common reed (Phragmites communis) is widely distributed as the dominant plant species in the Songnen Plain of China. The aim of this study was to investigate different physiological adaptive mechanisms to salinity tolerance between young and old leaves. The profiles of 68 metabolites were measured and studied in reed leaves by gas chromatography-mass spectrometer. The nitrogen, carbon, and pigment contents showed stronger growth inhibition for older leaves with salinity stress. In young leaves, high K + contents not only promoted cell growth, but also prevented influx of superfluous Na + ions in cells; the Ca 2+ accumulation in old leaves implied that Ca 2+ triggered the SOS-Na + exclusion system and reduced Na + toxicity. Thus, the mechanism of enhanced tolerance differed between young and old leaves. The metabolite results indicated that the young and old leaves had different mechanisms of osmotic regulation; sugars/polyols and amino acids played important roles in developing salinity tolerance in young leaves but high contents of fatty acids were important for old leaves. These results implied dramatically enhanced sugars and amino acid synthesis but inhibited energy metabolism in young leaves. In contrast, fatty acid synthesis was enhanced in old leaves. The results extended our understanding of the differences in physiological metabolism in adaptive to the salt-alkalization of soil in Songnen grassland between young and old leaves of reeds. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Peptidase inhibitors in tick physiology.

PubMed

Parizi, L F; Ali, A; Tirloni, L; Oldiges, D P; Sabadin, G A; Coutinho, M L; Seixas, A; Logullo, C; Termignoni, C; DA Silva Vaz, I

2018-06-01

Peptidase inhibitors regulate a wide range of physiological processes involved in the interaction between hematophagous parasites and their hosts, including tissue remodeling, the immune response and blood coagulation. In tick physiology, peptidase inhibitors have a crucial role in adaptation to improve parasitism mechanisms, facilitating blood feeding by interfering with defense-related host peptidases. Recently, a larger number of studies on this topic led to the description of several new tick inhibitors displaying interesting novel features, for example a role in pathogen transmission to the host. A comprehensive review discussing these emerging concepts can therefore shed light on peptidase inhibitor functions, their relevance to tick physiology and their potential applications. Here, we summarize and examine the general characteristics, functional diversity and action of tick peptidase inhibitors with known physiological roles in the tick-host-pathogen interaction. © 2017 The Royal Entomological Society.

Design and rationale of the assessment of proper physiologic response with rate adaptive pacing driven by minute ventilation or accelerometer (APPROPRIATE) trial.

PubMed

Gilliam, F Roosevelt; Giudici, Michael; Benn, Andrew; Koplan, Bruce; Berg, Kellie Jean Chase; Kraus, Stacia Merkel; Stolen, Kira Q; Alvarez, Guy E; Hopper, Donald L; Wilkoff, Bruce L

2011-02-01

Rate-adaptive sensors are designed to restore a physiologic heart rate response to activity, in particular for patients that have chronotropic incompetence (CI). Limited data exist comparing two primary types of sensors; an accelerometer (XL) sensor which detects activity or motion and a minute ventilation (MV) sensor, which detects the product of respiration rate and tidal volume. The APPROPRIATE study will evaluate the MV sensor compared with the XL sensor for superiority in improving functional capacity (peak VO(2)) in pacemaker patients that have CI. This study is a double-blind, randomized, two-arm trial that will enroll approximately 1,000 pacemaker patients. Patients will complete a 6-min walk test at the 2-week visit to screen for potential CI. Those projected to have CI will advance to a 1-month visit. At the 1-month visit, final determination of CI will be done by completing a peak exercise treadmill test while the pacemaker is programmed to DDDR with the device sensors set to passive. Patients failing to meet the study criteria for CI will not continue further in the trial. Patients that demonstrate CI will be randomized to program their rate-adaptive sensors to either MV or XL in a 1:1 ratio. The rate-adaptive sensor will be optimized for each patient using a short walk to determine the appropriate response factor. At a 2-month visit, patients will complete a CPX test with the rate-adaptive sensors in their randomized setting.

Perspectives: Gene Expression in Fisheries Management

USGS Publications Warehouse

Nielsen, Jennifer L.; Pavey, Scott A.

2010-01-01

Functional genes and gene expression have been connected to physiological traits linked to effective production and broodstock selection in aquaculture, selective implications of commercial fish harvest, and adaptive changes reflected in non-commercial fish populations subject to human disturbance and climate change. Gene mapping using single nucleotide polymorphisms (SNPs) to identify functional genes, gene expression (analogue microarrays and real-time PCR), and digital sequencing technologies looking at RNA transcripts present new concepts and opportunities in support of effective and sustainable fisheries. Genomic tools have been rapidly growing in aquaculture research addressing aspects of fish health, toxicology, and early development. Genomic technologies linking effects in functional genes involved in growth, maturation and life history development have been tied to selection resulting from harvest practices. Incorporating new and ever-increasing knowledge of fish genomes is opening a different perspective on local adaptation that will prove invaluable in wild fish conservation and management. Conservation of fish stocks is rapidly incorporating research on critical adaptive responses directed at the effects of human disturbance and climate change through gene expression studies. Genomic studies of fish populations can be generally grouped into three broad categories: 1) evolutionary genomics and biodiversity; 2) adaptive physiological responses to a changing environment; and 3) adaptive behavioral genomics and life history diversity. We review current genomic research in fisheries focusing on those that use microarrays to explore differences in gene expression among phenotypes and within or across populations, information that is critically important to the conservation of fish and their relationship to humans.

Genetic diversification of chemokine CXCL16 and its receptor CXCR6 in primates.

PubMed

Xu, Feifei; He, Dan; Liu, Jiabin; Ni, Qingyong; Lyu, Yongqing; Xiong, Shiqiu; Li, Yan

2018-08-01

Chemokine CXCL16 and its receptor CXCR6 are associated with a series of physiological and pathological processes in cooperative and stand-alone fashions. To shed insight into their versatile nature, we studied genetic variations of CXCL16 and CXCR6 in primates. Evolutionary analyses revealed that these genes underwent a similar evolutionary fate. Both genes experienced adaptive diversification with the phylogenetic division of cercopithecoids (Old World monkeys) and hominoids (humans, great apes, and gibbons) from their common ancestor. In contrast, they were conserved in the periods preceding and following the dividing process. In terms of the adaptive diversification between cercopithecoids and hominoids, the adaptive genetic changes have occurred in the mucin-like and chemokine domains of CXCL16 and the N-terminus and transmembrane helixes of CXCR6. In combination with currently available structural and functional information for CXCL16 and CXCR6, the parallels between the evolutionary footprints and the co-occurrence of adaptive diversification at some evolutionary stage suggest that interplay could exist between the diversification-related amino acid sites, or between the domains on which the identified sites are located, in physiological processes such as chemotaxis and/or cell adhesion. Copyright © 2018 Elsevier Ltd. All rights reserved.

PSYCHOSOCIAL INTERVENTION EFFECTS ON ADAPTATION, DISEASE COURSE AND BIOBEHAVIORAL PROCESSES IN CANCER

PubMed Central

Antoni, Michael H.

2012-01-01

A diagnosis of cancer and subsequent treatments place demands on psychological adaptation. Behavioral research suggests the importance of cognitive, behavioral, and social factors in facilitating adaptation during active treatment and throughout cancer survivorship, which forms the rationale for the use of many psychosocial interventions in cancer patients. This cancer experience may also affect physiological adaptation systems (e.g., neuroendocrine) in parallel with psychological adaptation changes (negative affect). Changes in adaptation may alter tumor growth-promoting processes (increased angiogenesis, migration and invasion, and inflammation) and tumor defense processes (decreased cellular immunity) relevant for cancer progression and the quality of life of cancer patients. Some evidence suggests that psychosocial intervention can improve psychological and physiological adaptation indicators in cancer patients. However, less is known about whether these interventions can influence tumor activity and tumor growth-promoting processes and whether changes in these processes could explain the psychosocial intervention effects on recurrence and survival documented to date. Documenting that psychosocial interventions can modulate molecular activities (e.g., transcriptional indicators of cell signaling) that govern tumor promoting and tumor defense processes on the one hand, and clinical disease course on the other is a key challenge for biobehavioral oncology research. This mini-review will summarize current knowledge on psychological and physiological adaptation processes affected throughout the stress of the cancer experience, and the effects of psychosocial interventions on psychological adaptation, cancer disease progression, and changes in stress-related biobehavioral processes that may mediate intervention effects on clinical cancer outcomes. Very recent intervention work in breast cancer will be used to illuminate emerging trends in molecular probes of interest in the hope of highlighting future paths that could move the field of biobehavioral oncology intervention research forward. PMID:22627072

Psychosocial intervention effects on adaptation, disease course and biobehavioral processes in cancer.

PubMed

Antoni, Michael H

2013-03-01

A diagnosis of cancer and subsequent treatments place demands on psychological adaptation. Behavioral research suggests the importance of cognitive, behavioral, and social factors in facilitating adaptation during active treatment and throughout cancer survivorship, which forms the rationale for the use of many psychosocial interventions in cancer patients. This cancer experience may also affect physiological adaptation systems (e.g., neuroendocrine) in parallel with psychological adaptation changes (negative affect). Changes in adaptation may alter tumor growth-promoting processes (increased angiogenesis, migration and invasion, and inflammation) and tumor defense processes (decreased cellular immunity) relevant for cancer progression and the quality of life of cancer patients. Some evidence suggests that psychosocial intervention can improve psychological and physiological adaptation indicators in cancer patients. However, less is known about whether these interventions can influence tumor activity and tumor growth-promoting processes and whether changes in these processes could explain the psychosocial intervention effects on recurrence and survival documented to date. Documenting that psychosocial interventions can modulate molecular activities (e.g., transcriptional indicators of cell signaling) that govern tumor promoting and tumor defense processes on the one hand, and clinical disease course on the other is a key challenge for biobehavioral oncology research. This mini-review will summarize current knowledge on psychological and physiological adaptation processes affected throughout the stress of the cancer experience, and the effects of psychosocial interventions on psychological adaptation, cancer disease progression, and changes in stress-related biobehavioral processes that may mediate intervention effects on clinical cancer outcomes. Very recent intervention work in breast cancer will be used to illuminate emerging trends in molecular probes of interest in the hope of highlighting future paths that could move the field of biobehavioral oncology intervention research forward. Copyright © 2012 Elsevier Inc. All rights reserved.

Mechanisms of β-cell functional adaptation to changes in workload

PubMed Central

Wortham, Matthew; Sander, Maike

2016-01-01

Insulin secretion must be tightly coupled to nutritional state to maintain blood glucose homeostasis. To this end, pancreatic β-cells sense and respond to changes in metabolic conditions, thereby anticipating insulin demands for a given physiological context. This is achieved in part through adjustments of nutrient metabolism, which is controlled at several levels including allosteric regulation, posttranslational modifications, and altered expression of metabolic enzymes. In this review, we discuss mechanisms of β-cell metabolic and functional adaptation in the context of two physiological states that alter glucose-stimulated insulin secretion: fasting and insulin resistance. We review current knowledge of metabolic changes that occur in the β-cell during adaptation and specifically discuss transcriptional mechanisms that underlie β-cell adaptation. A more comprehensive understanding of how β-cells adapt to changes in nutrient state could identify mechanisms to be co-opted for therapeutically modulating insulin secretion in metabolic disease. PMID:27615135

Extra-auditory responses to long-term intermittent noise stimulation in humans.

PubMed

Fruhstorfer, B; Hensel, H

1980-12-01

Respiration, heart rate, cutaneous blood flow, and electroencephalogram (EEG) reactions to long-term intermittent noise exposure were recorded from 13 volunteers (20-29 yr) with normal hearing and vegetative reactivity. They received daily within 1 h 12 noise stimuli (16 s 100 dB (A) white noise) for 10 or 21 days, respectively. Most subjects reported partial subjective adaptation to the noise. Heart rate adapted within a session but did not change considerably during successive days. Vascular responses did not change during one session but diminished mainly during the first 10 days. Noise responses in the EEG remained constant, but a decrease in vigilance occurred during the whole experimental series. Respiration responses were unpredictable and showed no trend within the sessions. It was concluded that certain physiological responses adapt to loud noise but that the time course of adaptation is different. Therefore a general statement about physiological noise adaptation is not possible.

Adaptation to Life in the High Andes: Nocturnal Oxyhemoglobin Saturation in Early Development

PubMed Central

Hill, Catherine Mary; Baya, Ana; Gavlak, Johanna; Carroll, Annette; Heathcote, Kate; Dimitriou, Dagmara; L'Esperance, Veline; Webster, Rebecca; Holloway, John; Virues-Ortega, Javier; Kirkham, Fenella Jane; Bucks, Romola Starr; Hogan, Alexandra Marie

2016-01-01

Study Objectives: Physiological adaptation to high altitude hypoxia may be impaired in Andeans with significant European ancestry. The respiratory ‘burden’ of sleep may challenge adaptation, leading to relative nocturnal hypoxia. Developmental aspects of sleep-related breathing in high-altitude native children have not previously been reported. We aimed to determine the influence of development on diurnal-nocturnal oxyhemoglobin differences in children living at high altitude. Methods: This was a cross-sectional, observational study. Seventy-five healthy Bolivian children aged 6 mo to 17 y, native to low altitude (500 m), moderate high altitude (2,500 m), and high altitude (3,700 m) were recruited. Daytime resting pulse oximetry was compared to overnight recordings using Masimo radical oximeters. Genetic ancestry was determined from DNA samples. Results: Children had mixed European/Amerindian ancestry, with no significant differences between altitudes. Sixty-two participants had ≥ 5 h of nocturnal, artifact-free data. As predicted, diurnal mean oxyhemoglobin saturation decreased across altitudes (infants and children, both P < 0.001), with lowest diurnal values at high altitude in infants. At high altitude, there was a greater drop in nocturnal mean oxyhemoglobin saturation (infants, P < 0.001; children, P = 0.039) and an increase in variability (all P ≤ 0.001) compared to low altitude. Importantly, diurnal to nocturnal altitude differences diminished (P = 0.036), from infancy to childhood, with no further change during adolescence. Conclusions: Physiological adaptation to high-altitude living in native Andeans is unlikely to compensate for the significant differences we observed between diurnal and nocturnal oxyhemoglobin saturation, most marked in infancy. This vulnerability to sleep-related hypoxia in early childhood has potential lifespan implications. Future studies should characterize the sleep- related respiratory physiology underpinning our observations. Citation: Hill CM, Baya A, Gavlak J, Carroll A, Heathcote K, Dimitriou D, L'Esperance V, Webster R, Holloway J, Virues-Ortega J, Kirkham FJ, Bucks RS, Hogan AM. Adaptation to life in the high andes: nocturnal oxyhemoglobin saturation in early development. SLEEP 2016;39(5):1001–1008. PMID:26951394

Physical culture as the basis of students' healthy lifestyle.

PubMed

Kharissova, N; Kharissova, L; Smirnov, I; Kosibaeva, A; Mindubaeva, F

2015-04-01

The present study aimed at investigation of the relationship between physiological features of cardiorespiratory system of a group of athletes with individually-typological charac-teristics of the organism (age, type of constitution, sports experience, the degree of adaptation) to physical activities on the basis of a comprehensive study of the cardiorespiratory system. The study was conducted on 450 students from 18 to 24 years of age from Kazakhstan, Russia, India, and Pakistan to evaluate the influence of physical culture and sports on the formation of a healthy lifestyle of young people in higher education institutions. The students were divided into groups - the first group - student 18-20 years of age; the second group - students 21-24 years of age; the control group included students of the same age not actively involved in sports (2 lessons of physical training per week). The relationship between physiological features of cardiorespiratory system of athletes and individually-typological characteristics of the organism (age, type of constitution, sports experience, the degree of adaptation) was determined.

Academic performance in human anatomy and physiology classes: a 2-yr study of academic motivation and grade expectation.

PubMed

Sturges, Diana; Maurer, Trent W; Allen, Deborah; Gatch, Delena Bell; Shankar, Padmini

2016-03-01

This project used a nonexperimental design with a convenience sample and studied the relationship between academic motivation, grade expectation, and academic performance in 1,210 students enrolled in undergraduate human anatomy and physiology (HAP) classes over a 2-yr period. A 42-item survey that included 28 items of the adapted academic motivation scale for HAP based on self-determination theory was administered in class during the first 3 wk of each semester. Students with higher grade point averages, who studied for longer hours and reported to be more motivated to succeed, did better academically in these classes. There was a significant relationship between students' scores on the adapted academic motivation scale and performance. Students were more extrinsically motivated to succeed in HAP courses than intrinsically motivated to succeed, and the analyses revealed that the most significant predictor of final grade was within the extrinsic scale (introjected and external types). Students' motivations remained stable throughout the course sequence. The data showed a significant relationship between HAP students' expected grade and their final grade in class. Finally, 65.5% of students overestimated their final grade, with 29% of students overestimating by two to four letter grades. Copyright © 2016 The American Physiological Society.

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

Hundreds of Genes Experienced Convergent Shifts in Selective Pressure in Marine Mammals

PubMed Central

Chikina, Maria; Robinson, Joseph D.; Clark, Nathan L.

2016-01-01

Abstract Mammal species have made the transition to the marine environment several times, and their lineages represent one of the classical examples of convergent evolution in morphological and physiological traits. Nevertheless, the genetic mechanisms of their phenotypic transition are poorly understood, and investigations into convergence at the molecular level have been inconclusive. While past studies have searched for convergent changes at specific amino acid sites, we propose an alternative strategy to identify those genes that experienced convergent changes in their selective pressures, visible as changes in evolutionary rate specifically in the marine lineages. We present evidence of widespread convergence at the gene level by identifying parallel shifts in evolutionary rate during three independent episodes of mammalian adaptation to the marine environment. Hundreds of genes accelerated their evolutionary rates in all three marine mammal lineages during their transition to aquatic life. These marine-accelerated genes are highly enriched for pathways that control recognized functional adaptations in marine mammals, including muscle physiology, lipid-metabolism, sensory systems, and skin and connective tissue. The accelerations resulted from both adaptive evolution as seen in skin and lung genes, and loss of function as in gustatory and olfactory genes. In regard to sensory systems, this finding provides further evidence that reduced senses of taste and smell are ubiquitous in marine mammals. Our analysis demonstrates the feasibility of identifying genes underlying convergent organism-level characteristics on a genome-wide scale and without prior knowledge of adaptations, and provides a powerful approach for investigating the physiological functions of mammalian genes. PMID:27329977

Human heat adaptation.

PubMed

Taylor, Nigel A S

2014-01-01

In this overview, human morphological and functional adaptations during naturally and artificially induced heat adaptation are explored. Through discussions of adaptation theory and practice, a theoretical basis is constructed for evaluating heat adaptation. It will be argued that some adaptations are specific to the treatment used, while others are generalized. Regarding ethnic differences in heat tolerance, the case is put that reported differences in heat tolerance are not due to natural selection, but can be explained on the basis of variations in adaptation opportunity. These concepts are expanded to illustrate how traditional heat adaptation and acclimatization represent forms of habituation, and thermal clamping (controlled hyperthermia) is proposed as a superior model for mechanistic research. Indeed, this technique has led to questioning the perceived wisdom of body-fluid changes, such as the expansion and subsequent decay of plasma volume, and sudomotor function, including sweat habituation and redistribution. Throughout, this contribution was aimed at taking another step toward understanding the phenomenon of heat adaptation and stimulating future research. In this regard, research questions are posed concerning the influence that variations in morphological configuration may exert upon adaptation, the determinants of postexercise plasma volume recovery, and the physiological mechanisms that modify the cholinergic sensitivity of sweat glands, and changes in basal metabolic rate and body core temperature following adaptation. © 2014 American Physiological Society.

System Theory and Physiological Processes.

PubMed

Jones, R W

1963-05-03

Engineers and physiologists working together in experimental and theoretical studies predict that the application of system analysis to biological processes will increase understanding of these processes and broaden the base of system theory. Richard W. Jones, professor of electrical engineering at Northwestern University, Evanston, Illinois, and John S. Gray, professor of physiology at Northwestern's Medical School, discuss these developments. Their articles are adapted from addresses delivered in Chicago in November 1962 at the 15th Annual Conference on Engineering in Medicine and Biology.

Sexually different morphological, physiological and molecular responses of Fraxinus mandshurica flowers to floral development and chilling stress.

PubMed

Zhu, Zhu; Qi, Fenghui; Yan, Chaofu; Zhan, Yaguang

2016-02-01

Fraxinus mandshurica is considered a dioecious hardwood, and the temporal separation of the maturation of the male and female flowers is one reason that F. mandshurica has become an endangered species in China. Rainfall and low temperature influence pollen formation and dispersal and the blooming of female flowers. Therefore, low fertilization efficiency strongly influences the population of F. mandshurica. Nevertheless, few studies have investigated the sex-specific morphological, physiological and molecular differentiation of F. mandshurica during flowering and its responses to low temperature. In this study, we investigated the sexual differences in the morphological, physiological, and biochemical parameters of F. mandshurica during flowering and determined the physiological and biochemical parameters and expression levels of related genes in response to low-temperature stress induced by exposure to 4 °C (chilling stress) during pollen dispersal and fertilization. Our study supports the hypothesis that male flowers suffer more severe injuries while female flowers are more adaptable to environmental stress during flower development in F. mandshurica. The results showed higher physiological and biochemical levels of malondialdehyde, proline, and soluble sugar, as well as the expression of genes involved in calcium signaling, cold shock and DNA methylation in male flowers compared with female flowers, which suggested that male flowers suffer from more serious peroxidation than female flowers. In contrast, higher antioxidant capacity and FmaCAT expression were detected in female flowers, providing preliminary evidence that male flowers rapidly fade after pollination and further demonstrating that female flowers need a much stronger antioxidant enzyme system to maintain embryonic growth. Most peaks related to physiological and molecular responses were observed at 2-4 h and 8-10 h of exposure to chilling stress in the female and male flowers, respectively. This trend implies that female flowers have higher adaptability to low temperature during fertilization. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body.

PubMed

Psikuta, Agnes; Kuklane, Kalev; Bogdan, Anna; Havenith, George; Annaheim, Simon; Rossi, René M

2016-03-01

Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development domain of clothing, automotive and building engineering.

Testing the role of phenotypic plasticity for local adaptation: growth and development in time-constrained Rana temporaria populations.

PubMed

Lind, M I; Johansson, F

2011-12-01

Phenotypic plasticity can be important for local adaptation, because it enables individuals to survive in a novel environment until genetic changes have been accumulated by genetic accommodation. By analysing the relationship between development rate and growth rate, it can be determined whether plasticity in life-history traits is caused by changed physiology or behaviour. We extended this to examine whether plasticity had been aiding local adaptation, by investigating whether the plastic response had been fixed in locally adapted populations. Tadpoles from island populations of Rana temporaria, locally adapted to different pool-drying regimes, were monitored in a common garden. Individual differences in development rate were caused by different foraging efficiency. However, developmental plasticity was physiologically mediated by trading off growth against development rate. Surprisingly, plasticity has not aided local adaptation to time-stressed environments, because local adaptation was not caused by genetic assimilation but on selection on the standing genetic variation in development time. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions.

PubMed

Clément, Gilles R; Bukley, Angelia P; Paloski, William H

2015-01-01

In spite of the experience gained in human space flight since Yuri Gagarin's historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth's gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth's surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented.

Regulation of Mammalian Physiology by Interconnected Circadian and Feeding Rhythms

PubMed Central

Atger, Florian; Mauvoisin, Daniel; Weger, Benjamin; Gobet, Cédric; Gachon, Frédéric

2017-01-01

Circadian clocks are endogenous timekeeping systems that adapt in an anticipatory fashion the physiology and behavior of most living organisms. In mammals, the master pacemaker resides in the suprachiasmatic nucleus and entrains peripheral clocks using a wide range of signals that differentially schedule physiology and gene expression in a tissue-specific manner. The peripheral clocks, such as those found in the liver, are particularly sensitive to rhythmic external cues like feeding behavior, which modulate the phase and amplitude of rhythmic gene expression. Consequently, the liver clock temporally tunes the expression of many genes involved in metabolism and physiology. However, the circadian modulation of cellular functions also relies on multiple layers of posttranscriptional and posttranslational regulation. Strikingly, these additional regulatory events may happen independently of any transcriptional oscillations, showing that complex regulatory networks ultimately drive circadian output functions. These rhythmic events also integrate feeding-related cues and adapt various metabolic processes to food availability schedules. The importance of such temporal regulation of metabolism is illustrated by metabolic dysfunctions and diseases resulting from circadian clock disruption or inappropriate feeding patterns. Therefore, the study of circadian clocks and rhythmic feeding behavior should be of interest to further advance our understanding of the prevention and therapy of metabolic diseases. PMID:28337174

The Development of Real-Time Physiological Monitoring and Training Software for Remote Applications

NASA Technical Reports Server (NTRS)

2005-01-01

Autogenic Feedback Training Exercise (AFTE) is an protocol and technology developed by Dr. Patricia Cowings and her associates at NASA Ames Research Center as a means to facilitate astronaut adaptation to space and exposure to the microgravity. AFTE is a training method which involves teaching subjects to voluntarily control several of their own physiological responses to environmental stressors. As the procedures matured, the training program was expanded to determine if technology developed to facilitate astronaut adaptation to space would be valuable in treating patients suffering from autonomic and vestibular pathologies and symptomatic relief from nausea and/or blood pressure control anomalies such as hypo- or hypertension. The present study, performed in conjunction with Morehouse School of Medicine, Biomedical Engineering at The University of Akron and NASA Ames Research Center has demonstrated that this technology can be successfully applied over vast distances. The specific purpose of this research was to develop a PC based system which could handle processing of twenty channels of acquired physiological data in addition to the necessary duplex communication protocols that would, for example, permit a patient in Atlanta, GA to be trained by a clinician stationed in San Jose, CA. Sixteen channels of physiological data and 20 channels of processed data are included.

Omics Approaches for Identifying Physiological Adaptations to Genome Instability in Aging.

PubMed

Edifizi, Diletta; Schumacher, Björn

2017-11-04

DNA damage causally contributes to aging and age-related diseases. The declining functioning of tissues and organs during aging can lead to the increased risk of succumbing to aging-associated diseases. Congenital syndromes that are caused by heritable mutations in DNA repair pathways lead to cancer susceptibility and accelerated aging, thus underlining the importance of genome maintenance for withstanding aging. High-throughput mass-spectrometry-based approaches have recently contributed to identifying signalling response networks and gaining a more comprehensive understanding of the physiological adaptations occurring upon unrepaired DNA damage. The insulin-like signalling pathway has been implicated in a DNA damage response (DDR) network that includes epidermal growth factor (EGF)-, AMP-activated protein kinases (AMPK)- and the target of rapamycin (TOR)-like signalling pathways, which are known regulators of growth, metabolism, and stress responses. The same pathways, together with the autophagy-mediated proteostatic response and the decline in energy metabolism have also been found to be similarly regulated during natural aging, suggesting striking parallels in the physiological adaptation upon persistent DNA damage due to DNA repair defects and long-term low-level DNA damage accumulation occurring during natural aging. These insights will be an important starting point to study the interplay between signalling networks involved in progeroid syndromes that are caused by DNA repair deficiencies and to gain new understanding of the consequences of DNA damage in the aging process.

Omics Approaches for Identifying Physiological Adaptations to Genome Instability in Aging

PubMed Central

Edifizi, Diletta; Schumacher, Björn

2017-01-01

DNA damage causally contributes to aging and age-related diseases. The declining functioning of tissues and organs during aging can lead to the increased risk of succumbing to aging-associated diseases. Congenital syndromes that are caused by heritable mutations in DNA repair pathways lead to cancer susceptibility and accelerated aging, thus underlining the importance of genome maintenance for withstanding aging. High-throughput mass-spectrometry-based approaches have recently contributed to identifying signalling response networks and gaining a more comprehensive understanding of the physiological adaptations occurring upon unrepaired DNA damage. The insulin-like signalling pathway has been implicated in a DNA damage response (DDR) network that includes epidermal growth factor (EGF)-, AMP-activated protein kinases (AMPK)- and the target of rapamycin (TOR)-like signalling pathways, which are known regulators of growth, metabolism, and stress responses. The same pathways, together with the autophagy-mediated proteostatic response and the decline in energy metabolism have also been found to be similarly regulated during natural aging, suggesting striking parallels in the physiological adaptation upon persistent DNA damage due to DNA repair defects and long-term low-level DNA damage accumulation occurring during natural aging. These insights will be an important starting point to study the interplay between signalling networks involved in progeroid syndromes that are caused by DNA repair deficiencies and to gain new understanding of the consequences of DNA damage in the aging process. PMID:29113067

Adaptive physiological response, carbon partitioning, and biomass production of Withania somnifera (L.) Dunal grown under elevated CO2 regimes.

PubMed

Sharma, Rupali; Singh, Hukum; Kaushik, Monica; Nautiyal, Raman; Singh, Ombir

2018-06-01

Winter cherry or Ashwagandha ( Withania somnifera ) is an important medicinal plant used in traditional and herbal medicine system. Yet, there is no information available on response of this plant to changing climatic conditions particularly elevated atmospheric CO 2 concentrations. Therefore, we conducted an experiment to examine the effect of elevated CO 2 concentrations (ECs) on Withania somnifera . The variations in traits of physiological adaptation, net primary productivity, carbon partitioning, morphology, and biomass in response to elevated CO 2 concentrations (ambient, 600 and 800 µmol mol -1 ) during one growth cycle were investigated within the open top chamber (OTC) facility in the foothill of the Himalayas, Dehardun, India. ECs significantly increased photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, soil respiration, net primary productivity and the carbon content of plant tissues (leaf, stem, and root), and soil carbon. Furthermore, ECs significantly enhanced biomass production (root and shoot), although declined night leaf respiration. Overall, it was summarized that photosynthesis, stomatal conductance, water use efficiency, leaf, and soil carbon and biomass increased under ECs rendering the physiological adaptation to the plant. Increased net primary productivity might facilitate mitigation effects by sequestering elevated levels of carbon dioxide. We advocate further studies to investigate the effects of ECs on the accumulation of secondary metabolites and health-promoting substances of this as well as other medicinal plants.

Psychophysiology of Humans in Space

NASA Technical Reports Server (NTRS)

Cowings, P.S.; Wade, Charles E. (Technical Monitor)

1994-01-01

Psychophysiological methods can provide aerospace medicine investigators with a unique perspective on the diagnosis and treatment of biomedical problems of humans in space. As psychophysiologists, we measure physiological responses to environmental stressors as a means of assessing and modifying their effects on behavior and performance. In the course of an 20-year research program. we have determined that this approach can be used to: (1) objectively identify physiological correlates of discomfort, malaise and performance; and (2) correct autonomic nervous system (ANS) disturbance and thereby increase tolerance to environmental stressors without the need for pharmacological intervention. The research presented will describe the application of psychophysiological methods for studying human adaptation to space and developing behavioral medicine techniques for facilitating this adaptation as well a readaptation to Earth. The goal of this work is to enhance the safety, comfort and operational efficiency of passengers and crew during spaceflight.

Interstrain variation in cardiac and respiratory adaptation to repeated ozone and particulate matter exposures.

PubMed

Hamade, Ali K; Tankersley, Clarke G

2009-04-01

Increased ambient particulate matter (PM) is associated with adverse cardiovascular and respiratory outcomes, as demonstrated by epidemiology studies. Several studies have investigated the role of copollutants, such as ozone (O(3)), in this association. It is accepted that physiological adaptation involving the respiratory system occurs with repeated exposures to O(3). We hypothesize that adaptation to PM and O(3) varies among different inbred mouse strains, and cardiopulmonary adaptation to O(3) is a synchronized response between the cardiac and respiratory systems. Heart rate (HR), HR variability (HRV), and the magnitude and pattern of breathing were simultaneously measured by implanted telemeters and by plethysmography in three inbred mouse strains: C57Bl/6J (B6), C3H/HeJ (HeJ), and C3H/HeOuJ (OuJ). Physiological responses were assessed during dual exposures to filtered air (FA), O(3) (576 +/- 32 parts/billion), and/or carbon black (CB; 556 +/- 34 mug/m(3)). Exposures were repeated for 3 consecutive days. While each strain showed significant reductions in HR during CB with O(3) preexposure (O(3)CB) on day 1, prominent HRV responses were observed in only HeJ and OuJ mice. Each strain also differed in their adaptation profile in response to repeated O(3)CB exposures. Whereas B6 mice showed rapid adaptation in HR after day 1, HeJ mice generally showed more moderate HR and HRV adaptation after day 2 of exposure. Unlike either B6 or HeJ strains, OuJ mice showed little evidence of HR or HRV adaptation to repeated O(3)CB exposure. Adaptation profiles between HR regulation and breathing characteristics were strongly correlated, but these associations also varied significantly among strains. These findings suggest that genetic factors determine the responsivity and adaptation of the cardiac and respiratory systems to repeated copollutant exposures. During O(3)CB exposure, adaptation of cardiac and respiratory systems is markedly synchronized, which may explain a potential mechanism for adverse effects of PM on heart function.

Interstrain variation in cardiac and respiratory adaptation to repeated ozone and particulate matter exposures

PubMed Central

Hamade, Ali K.; Tankersley, Clarke G.

2009-01-01

Increased ambient particulate matter (PM) is associated with adverse cardiovascular and respiratory outcomes, as demonstrated by epidemiology studies. Several studies have investigated the role of copollutants, such as ozone (O3), in this association. It is accepted that physiological adaptation involving the respiratory system occurs with repeated exposures to O3. We hypothesize that adaptation to PM and O3 varies among different inbred mouse strains, and cardiopulmonary adaptation to O3 is a synchronized response between the cardiac and respiratory systems. Heart rate (HR), HR variability (HRV), and the magnitude and pattern of breathing were simultaneously measured by implanted telemeters and by plethysmography in three inbred mouse strains: C57Bl/6J (B6), C3H/HeJ (HeJ), and C3H/HeOuJ (OuJ). Physiological responses were assessed during dual exposures to filtered air (FA), O3 (576 ± 32 parts/billion), and/or carbon black (CB; 556 ± 34 μg/m3). Exposures were repeated for 3 consecutive days. While each strain showed significant reductions in HR during CB with O3 preexposure (O3CB) on day 1, prominent HRV responses were observed in only HeJ and OuJ mice. Each strain also differed in their adaptation profile in response to repeated O3CB exposures. Whereas B6 mice showed rapid adaptation in HR after day 1, HeJ mice generally showed more moderate HR and HRV adaptation after day 2 of exposure. Unlike either B6 or HeJ strains, OuJ mice showed little evidence of HR or HRV adaptation to repeated O3CB exposure. Adaptation profiles between HR regulation and breathing characteristics were strongly correlated, but these associations also varied significantly among strains. These findings suggest that genetic factors determine the responsivity and adaptation of the cardiac and respiratory systems to repeated copollutant exposures. During O3CB exposure, adaptation of cardiac and respiratory systems is markedly synchronized, which may explain a potential mechanism for adverse effects of PM on heart function. PMID:19158411

Repeated exposure to immobilization or two different footshock intensities reveals differential adaptation of the hypothalamic-pituitary-adrenal axis.

PubMed

Rabasa, Cristina; Muñoz-Abellán, Cristina; Daviu, Núria; Nadal, Roser; Armario, Antonio

2011-05-03

Factors involved in adaptation to repeated stress are not well-characterized. For instance, acute footshock (FS) of high intensity appears to be less severe than immobilization (IMO) in light of the speed of post-stress recovery of the hypothalamic-pituitary-adrenal (HPA) axis and other physiological variables. However, repeated exposure to IMO consistently resulted in reduction of the HPA response to the same stressor (adaptation), whereas failure to adapt has been usually reported after FS. Thus, in the present work we directly compared the activation of HPA axis and other physiological changes in response to both acute and repeated exposure to IMO and two intensities of FS (medium and high) in adult male rats. Control rats were exposed to the FS boxes but they did not receive shocks. Daily repeated exposure to IMO resulted in significant adaptation of the overall ACTH and corticosterone responses to the stressor. Such a reduction was also observed with repeated exposure to FS boxes and FS-medium, whereas repeated exposure to FS-high only resulted in a small reduction of the corticosterone response during the post-stress period. This suggests that some properties of FS-high make adaptation to it difficult. Interestingly, overall changes in food intake and body weight gain throughout the week of exposure to the stressors reveal a greater impact of IMO than FS-high, indicating that factors other than the intensity of a stressor, at least when evaluated in function of the above physiological variables, can influence HPA adaptation. Since FS exposure is likely to cause more pain than IMO, activation of nociceptive signals above a certain level may negatively affect HPA adaptation to repeated stressors. Copyright © 2011 Elsevier Inc. All rights reserved.

Adaptive optics ophthalmoscopy: results and applications.

PubMed

Pallikaris, A

2005-01-01

The living human eye's optical aberrations set a limit to retinal imaging in the clinical setting. Progress in the field of adaptive optics has offered unique solutions to this problem. The purpose of this review is to summarize the most recent advances in adaptive optics ophthalmoscopy. Adaptive optics technology has been combined with flood illumination imaging, confocal scanning laser ophthalmoscopy, and optical coherence tomography for the high resolution imaging of the retina. The advent of adaptive optics technology has provided the technical platform for the compensation of the eye's aberration and made possible the observation of single cones, small capillaries, nerve fibers, and leukocyte dynamics as well as the ultrastructure of the optic nerve head lamina cribrosa in vivo. Detailed imaging of retinal infrastructure provides valuable information for the study of retinal physiology and pathology.

ADAPTIVE REAL-TIME CARDIAC MRI USING PARADISE: VALIDATION BY THE PHYSIOLOGICALLY IMPROVED NCAT PHANTOM

PubMed Central

Sharif, Behzad; Bresler, Yoram

2013-01-01

Patient-Adaptive Reconstruction and Acquisition Dynamic Imaging with Sensitivity Encoding (PARADISE) is a dynamic MR imaging scheme that optimally combines parallel imaging and model-based adaptive acquisition. In this work, we propose the application of PARADISE to real-time cardiac MRI. We introduce a physiologically improved version of a realistic four-dimensional cardiac-torso (NCAT) phantom, which incorporates natural beat-to-beat heart rate and motion variations. Cardiac cine imaging using PARADISE is simulated and its performance is analyzed by virtue of the improved phantom. Results verify the effectiveness of PARADISE for high resolution un-gated real-time cardiac MRI and its superiority over conventional acquisition methods. PMID:24398475

A Chemosensory Adaptation Module for the Physiology Laboratory from Student-Directed "C. elegans" Research

ERIC Educational Resources Information Center

Lindblom, Tim

2006-01-01

The model organism, "Caenorhabditis elegans," in addition to being well suited to genetics and cell biology teaching applications, can also be useful in the physiology laboratory. In this article, the author describes how students in a junior level college Comparative Physiology course have made use of "C. elegans" in semester-long,…

Cardiotrophin 1 stimulates beneficial myogenic and vascular remodeling of the heart.

PubMed

Abdul-Ghani, Mohammad; Suen, Colin; Jiang, Baohua; Deng, Yupu; Weldrick, Jonathan J; Putinski, Charis; Brunette, Steve; Fernando, Pasan; Lee, Tom T; Flynn, Peter; Leenen, Frans H H; Burgon, Patrick G; Stewart, Duncan J; Megeney, Lynn A

2017-10-01

The post-natal heart adapts to stress and overload through hypertrophic growth, a process that may be pathologic or beneficial (physiologic hypertrophy). Physiologic hypertrophy improves cardiac performance in both healthy and diseased individuals, yet the mechanisms that propagate this favorable adaptation remain poorly defined. We identify the cytokine cardiotrophin 1 (CT1) as a factor capable of recapitulating the key features of physiologic growth of the heart including transient and reversible hypertrophy of the myocardium, and stimulation of cardiomyocyte-derived angiogenic signals leading to increased vascularity. The capacity of CT1 to induce physiologic hypertrophy originates from a CK2-mediated restraining of caspase activation, preventing the transition to unrestrained pathologic growth. Exogenous CT1 protein delivery attenuated pathology and restored contractile function in a severe model of right heart failure, suggesting a novel treatment option for this intractable cardiac disease.

Adaptation of bone to physiological stimuli.

PubMed

Judex, S; Gross, T S; Bray, R C; Zernicke, R F

1997-05-01

The ability of bone to alter its morphology in response to local physical stimuli is predicated upon the appropriate recruitment of bone cell populations. In turn, the ability to initiate cellular recruitment is influenced by numerous local and systemic factors. In this paper, we discuss data from three ongoing projects from our laboratory that examine how physiological processes influence adaptation and growth in the skeleton. In the first study, we recorded in vivo strains to quantify the locomotion-induced distribution of two parameters closely related to bone fluid flow strain rate and strain gradients. We found that the magnitude of these parameters (and thus the implied fluid flow) varies substantially within a given cross-section, and that while strain rate magnitude increases uniformly with elevated speed, strain gradients increase focally as gait speed is increased. Secondly, we examined the influence of vascular alterations on bone adaptation by assessing bone blood flow and bone mechanical properties in an in vivo model of trauma-induced joint laxity. A strong negative correlation (r2 = 0.8) was found between increased blood flow (76%) in the primary and secondary spongiosa and decreased stiffness (-34%) following 14 weeks of joint laxity. These data suggest that blood flow and/or vascular adaptation may interact closely with bone adaptation initiated by trauma. Thirdly, we examined the effect of a systemic influence upon skeletal health. After 4 weeks old rats were fed high fat-sucrose diets for 2 yr, their bone mechanical properties were significantly reduced. These changes were primarily due to interference with normal calcium absorption. In the aggregate, these studies emphasize the complexity of bone's normal physical environment, and also illustrate the potential interactions of local and systemic factors upon the process by which bone adapts to physical stimuli.

Physiological responses to salt stress of salt-adapted and directly salt (NaCl and NaCl+Na2SO4 mixture)-stressed cyanobacterium Anabaena fertilissima.

PubMed

Swapnil, Prashant; Rai, Ashwani K

2018-05-01

Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na 2 SO 4 ). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na 2 SO 4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity. Despite higher Na + concentration in the salt mixture, equimolar NaCl appeared more inhibitive to growth. Sucrose and trehalose content and antioxidant activities were maximal in 250 mM NaCl-treated cells, followed by salt mixture and was almost identical in salt-adapted (exposed to 500 mm NaCl) and control cells, except a marginal increase in ascorbate peroxidase activity and an additional fourth superoxide dismutase isoform. Catalase isoform of 63 kDa was induced only in salt-stressed cells. Salinity increased the uptake of intracellular Na + and Ca 2+ and leakage of K + in parent cells, while cation level in salt-adapted cells was comparable to control. Though there was differential increase in intracellular Ca 2+ under different salt treatments, ratio of Ca 2+ /Na + remained the same. It is inferred that stepwise increment in the salt concentration enabled the cyanobacterium to undergo priming effect and acquire robust and efficient defense system involving the least energy.

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke.

PubMed

Clark, David J; Chatterjee, Sudeshna A; McGuirk, Theresa E; Porges, Eric C; Fox, Emily J; Balasubramanian, Chitralakshmi K

2018-02-01

Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist scoring of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities-specific Balance Confidence Scale, respectively. There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. Published by Elsevier B.V.

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke

PubMed Central

Clark, David J.; Chatterjee, Sudeshna A.; McGuirk, Theresa E.; Porges, Eric C.; Fox, Emily J.; Balasubramanian, Chitralakshmi K.

2018-01-01

Background Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Methods Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist grading of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities Specific Balance Confidence Scale, respectively. Results There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. Conclusion This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. PMID:29216598

Integrated Physiological Mechanisms of Exercise Performance, Adaptation, and Maladaptation to Heat Stress

DTIC Science & Technology

2011-10-01

performance. We discuss novel systemic (heat acclimation) and cellular ( acquired thermal tolerance) adaptations that improve performance in hot and...cellular ( acquired thermal tolerance) adaptations that improve perfor- mance in hot and temperate environments and protect organs from heat stroke as...performance; (iii) newly identified adaptations associated with heat accli- mation/ acquired thermal tolerance that impact exercise-heat tolerance; (iv

Physiological adaptation to the humid tropics with special reference to the West African Dwarf (WAD) goat.

PubMed

Daramola, J O; Adeloye, A A

2009-10-01

West African Dwarf (WAD) goats are widely distributed in the subhumid and humid zones of Africa but are particularly associated with less favourable environments. Adaptive features such as feeding behaviour, efficiency of feed use and disease tolerance enable WAD goats to thrive on natural resources left untouched by other domestic ruminants. In marginal environments this goat remains the only domestic species that is able to survive. Among its physiological features small body size and low metabolic requirements are important traits that enable the animal to minimize its requirements in area or season where food sources are limited in quality and quantity. Specialized feeding behaviour and an efficient digestive system enable the animal to maximize food intake. Coat colour plays an important role in the evolved adaptation of this goat type. Reproductive fitness as manifested by prolific breeding is a major factor of adaptation. Defence mechanisms against infectious agents enable this type to thrive well in the hot humid tropics. The mechanisms involved in the regulation of these physiological functions of WAD goat are discussed. An understanding of these mechanisms could result in the development of improved techniques for enhancing goat productivity in humid environments.

The influence of surround suppression on adaptation effects in primary visual cortex

PubMed Central

Wissig, Stephanie C.

2012-01-01

Adaptation, the prolonged presentation of stimuli, has been used to probe mechanisms of visual processing in physiological, imaging, and perceptual studies. Previous neurophysiological studies have measured adaptation effects by using stimuli tailored to evoke robust responses in individual neurons. This approach provides an incomplete view of how an adapter alters the representation of sensory stimuli by a population of neurons with diverse functional properties. We implanted microelectrode arrays in primary visual cortex (V1) of macaque monkeys and measured orientation tuning and contrast sensitivity in populations of neurons before and after prolonged adaptation. Whereas previous studies in V1 have reported that adaptation causes stimulus-specific suppression of responsivity and repulsive shifts in tuning preference, we have found that adaptation can also lead to response facilitation and shifts in tuning toward the adapter. To explain this range of effects, we have proposed and tested a simple model that employs stimulus-specific suppression in both the receptive field and the spatial surround. The predicted effects on tuning depend on the relative drive provided by the adapter to these two receptive field components. Our data reveal that adaptation can have a much richer repertoire of effects on neuronal responsivity and tuning than previously considered and suggest an intimate mechanistic relationship between spatial and temporal contextual effects. PMID:22423001

Adaptation of the pituitary-adrenal axis to daily repeated forced swim exposure in rats is dependent on the temperature of water.

PubMed

Rabasa, Cristina; Delgado-Morales, Raúl; Gómez-Román, Almudena; Nadal, Roser; Armario, Antonio

2013-11-01

Comparison of exposure to certain predominantly emotional stressors reveals a qualitatively similar neuroendocrine response profile as well as a reduction of physiological responses after daily repeated exposure (adaptation). However, particular physical components of the stressor may interfere with adaptation. As defective adaptation to stress can enhance the probability to develop pathologies, we studied in adult male rats (n = 10/group) swimming behavior (struggling, immobility and mild swim) and physiological responses (ACTH, corticosterone and rectal temperature) to daily repeated exposure to forced swim (20 min, 13 d) at 25 or 36 °C (swim25 or swim36). Rats were repeatedly blood-sampled by tail-nick and hormones measured by radioimmunoassay. Some differences were observed between the two swim temperature groups after the first exposure to forced swim: (a) active behaviors were greater in swim25 than swim36 groups; (b) swim25 but not swim36 caused hypothermia; and (c) swim36 elicited the same ACTH response as swim25, but plasma corticosterone concentration was lower for swim36 at 30 min post-swim. After daily repeated exposure, adaptation in ACTH secretion was observed with swim36 already on day 4, whereas with swim25 adaptation was not observed until day 13 and was of lower magnitude. Nevertheless, after repeated exposure to swim25 a partial protection from hypothermia was observed and the two swim conditions resulted in progressive reduction of active behaviors. Thus, daily repeated swim at 25 °C impairs adaptation of the hypothalamic-pituitary-adrenal axis as compared to swim at 36 °C, supporting the hypothesis that certain physical components of predominantly emotional stressors can interfere with the process of adaptation.

Impact of extreme exercise at high altitude on oxidative stress in humans.

PubMed

Quindry, John; Dumke, Charles; Slivka, Dustin; Ruby, Brent

2016-09-15

Exercise and oxidative stress research continues to grow as a physiological subdiscipline. The influence of high altitude on exercise and oxidative stress is among the recent topics of intense study in this area. Early findings indicate that exercise at high altitude has an independent influence on free radical generation and the resultant oxidative stress. This review provides a detailed summary of oxidative stress biochemistry as gleaned mainly from studies of humans exercising at high altitude. Understanding of the human response to exercise at altitude is largely derived from field-based research at altitudes above 3000 m in addition to laboratory studies which employ normobaric hypoxia. The implications of oxidative stress incurred during high altitude exercise appear to be a transient increase in oxidative damage followed by redox-sensitive adaptations in multiple tissues. These outcomes are consistent for lowland natives, high altitude acclimated sojourners and highland natives, although the latter group exhibits a more robust adaptive response. To date there is no evidence that altitude-induced oxidative stress is deleterious to normal training or recovery scenarios. Limited evidence suggests that deleterious outcomes related to oxidative stress are limited to instances where individuals are exposed to extreme elevations for extended durations. However, confirmation of this tentative conclusion requires further investigation. More applicably, altitude-induced hypoxia may have an independent influence on redox-sensitive adaptive responses to exercise and exercise recovery. If correct, these findings may hold important implications for athletes, mountaineers, and soldiers working at high altitude. These points are raised within the confines of published research on the topic of oxidative stress during exercise at altitude. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Exercise intensity and muscle hypertrophy in blood flow-restricted limbs and non-restricted muscles: a brief review.

PubMed

Abe, Takashi; Loenneke, Jeremy P; Fahs, Christopher A; Rossow, Lindy M; Thiebaud, Robert S; Bemben, Michael G

2012-07-01

Although evidence for high-intensity resistance training-induced muscle hypertrophy has accumulated over the last several decades, the basic concept of the training can be traced back to ancient Greece: Milo of Croton lifted a bull-calf daily until it was fully grown, which would be known today as progressive overload. Now, in the 21st century, different types of training are being tested and studied, such as low-intensity exercise combined with arterial as well as venous blood flow restriction (BFR) to/from the working muscles. Because BFR training requires the use of a cuff that is placed at the proximal ends of the arms and/or legs, the BFR is only applicable to limb muscles. Consequently, most previous BFR training studies have focused on the physiological adaptations of BFR limb muscles. Muscle adaptations in non-BFR muscles of the hip and trunk are lesser known. Recent studies that have reported both limb and trunk muscle adaptations following BFR exercise training suggest that low-intensity (20-30% of 1RM) resistance training combined with BFR elicits muscle hypertrophy in both BFR limb and non-BFR muscles. However, the combination of leg muscle BFR with walk training elicits muscle hypertrophy only in the BFR leg muscles. In contrast to resistance exercise with BFR, the exercise intensity may be too low during BFR walk training to cause muscle hypertrophy in the non-BFR gluteus maximus and other trunk muscles. Other mechanisms including hypoxia, local and systemic growth factors and muscle cell swelling may also potentially affect the hypertrophic response of non-BFR muscles to BFR resistance exercise. © 2012 The Authors Clinical Physiology and Functional Imaging © 2012 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Temperature relations of aerial and aquatic physiological performance in a mid-intertidal limpet Cellana toreuma: adaptation to rapid changes in thermal stress during emersion.

PubMed

Huang, Xiongwei; Wang, Tifeng; Ye, Ziwen; Han, Guodong; Dong, Yunwei

2015-01-01

The physiological performance of a mid-intertidal limpet Cellana toreuma was determined to study the physiological adaptation of intertidal animals to rapid changes and extreme temperatures during emersion. The relationship between the Arrhenius breakpoint temperature (ABT) and in situ operative body temperature was studied to predict the possible impact of climate change on the species. The temperature coefficient (Q10) of emersed animals was higher than that of submersed animals and the ratio of aerial: aquatic heart rate rose with increasing temperature. The ABTs of submersed and emersed animals were 30.2 and 34.2°C, respectively. The heart rate and levels of molecular biomarkers (hsps, ampkα, ampkβ and sirt1 mRNA) were determined in 48 h simulated semi-diurnal tides. There were no obvious changes of heart rate and gene expression during the transition between emersion and submersion at room temperature, although expressions of hsp70 and hsp90 were induced significantly after thermal stress. These results indicate that C. toreuma can effectively utilize atmospheric oxygen, and the higher Q10 and ABT of emersed animals are adaptations to the rapid change and extreme thermal stress during emersion. However, the in situ operative body temperature frequently exceeds the aerial ABT of C. toreuma, indicating the occurrence of large-scale mortality of C. toreuma in summer, and this species should be sensitive to increasing temperature in the scenario of climate change. © 2014 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

BEYOND THE PALEOLITHIC PRESCRIPTION: INCORPORATING DIVERSITY AND FLEXIBILITY IN THE STUDY OF HUMAN DIET EVOLUTION

PubMed Central

Turner, Bethany L.; Thompson, Amanda L.

2014-01-01

Evolutionary paradigms of human health and nutrition center on the evolutionary discordance or “mismatch” model whereby human bodies, reflecting adaptations established in the Paleolithic era, are ill-suited to modern industrialized diets resulting in rapidly increasing rates of chronic metabolic disease. Whereas this model remains useful, we argue that its utility in explaining the evolution of human dietary tendencies is limited. The assumption that human diets are mismatched to our evolved biology implies that they are instinctual or genetically determined and rooted in the Paleolithic. We review current research indicating that human eating habits are primarily learned through behavioral, social and physiological mechanisms starting in utero and extending throughout the life course. Those adaptations that appear to be strongly genetic likely reflect Neolithic, rather than Paleolithic, adaptations and are significantly influenced by human niche-constructing behavior. Incorporating a broader understanding of the evolved mechanisms by which humans learn and imprint eating habits and the reciprocal effects of those habits on physiology would provide useful tools for structuring more lasting nutrition interventions. PMID:23865796

Synergistic and Antagonistic Effects of Thermal Shock, Air Exposure, and Fishing Capture on the Physiological Stress of Squilla mantis (Stomatopoda)

PubMed Central

Raicevich, Saša; Minute, Fabrizio; Finoia, Maria Grazia; Caranfa, Francesca; Di Muro, Paolo; Scapolan, Lucia; Beltramini, Mariano

2014-01-01

This study is aimed at assessing the effects of multiple stressors (thermal shock, fishing capture, and exposure to air) on the benthic stomatopod Squilla mantis, a burrowing crustacean quite widespread in the Mediterranean Sea. Laboratory analyses were carried out to explore the physiological impairment onset over time, based on emersion and thermal shocks, on farmed individuals. Parallel field-based studies were carried out to also investigate the role of fishing (i.e., otter trawling) in inducing physiological imbalance in different seasonal conditions. The dynamics of physiological recovery from physiological disruption were also studied. Physiological stress was assessed by analysing hemolymph metabolites (L-Lactate, D-glucose, ammonia, and H+), as well as glycogen concentration in muscle tissues. The experiments were carried out according to a factorial scheme considering the three factors (thermal shock, fishing capture, and exposure to air) at two fixed levels in order to explore possible synergistic, additive, or antagonistic effects among factors. Additive effects on physiological parameters were mainly detected when the three factors interacted together while synergistic effects were found as effect of the combination of two factors. This finding highlights that the physiological adaptive and maladaptive processes induced by the stressors result in a dynamic response that may encounter physiological limits when high stress levels are sustained. Thus, a further increase in the physiological parameters due to synergies cannot be reached. Moreover, when critical limits are encountered, mortality occurs and physiological parameters reflect the response of the last survivors. In the light of our mortality studies, thermal shock and exposure to air have the main effect on the survival of S. mantis only on trawled individuals, while lab-farmed individuals did not show any mortality during exposure to air until after 2 hours. PMID:25133593

Common functional targets of adaptive micro- and macro-evolutionary divergence in killifish.

PubMed

Whitehead, Andrew; Zhang, Shujun; Roach, Jennifer L; Galvez, Fernando

2013-07-01

Environmental salinity presents a key barrier to dispersal for most aquatic organisms, and adaptation to alternate osmotic environments likely enables species diversification. Little is known of the functional basis for derived tolerance to environmental salinity. We integrate comparative physiology and functional genomics to explore the mechanistic underpinnings of evolved variation in osmotic plasticity within and among two species of killifish; Fundulus majalis harbours the ancestral mainly salt-tolerant phenotype, whereas Fundulus heteroclitus harbours a derived physiology that retains extreme salt tolerance but with expanded osmotic plasticity towards the freshwater end of the osmotic continuum. Common-garden comparative hypo-osmotic challenge experiments show that F. heteroclitus is capable of remodelling gill epithelia more quickly and at more extreme osmotic challenge than F. majalis. We detect an unusual pattern of baseline transcriptome divergence, where neutral evolutionary processes appear to govern expression divergence within species, but patterns of divergence for these genes between species do not follow neutral expectations. During acclimation, genome expression profiling identifies mechanisms of acclimation-associated response that are conserved within the genus including regulation of paracellular permeability. In contrast, several responses vary among species including those putatively associated with cell volume regulation, and these same mechanisms are targets for adaptive physiological divergence along osmotic gradients within F. heteroclitus. As such, the genomic and physiological mechanisms that are associated with adaptive fine-tuning within species also contribute to macro-evolutionary divergence as species diversify across osmotic niches. © 2013 John Wiley & Sons Ltd.

Silicon central pattern generators for cardiac diseases

PubMed Central

Nogaret, Alain; O'Callaghan, Erin L; Lataro, Renata M; Salgado, Helio C; Meliza, C Daniel; Duncan, Edward; Abarbanel, Henry D I; Paton, Julian F R

2015-01-01

Cardiac rhythm management devices provide therapies for both arrhythmias and resynchronisation but not heart failure, which affects millions of patients worldwide. This paper reviews recent advances in biophysics and mathematical engineering that provide a novel technological platform for addressing heart disease and enabling beat-to-beat adaptation of cardiac pacing in response to physiological feedback. The technology consists of silicon hardware central pattern generators (hCPGs) that may be trained to emulate accurately the dynamical response of biological central pattern generators (bCPGs). We discuss the limitations of present CPGs and appraise the advantages of analog over digital circuits for application in bioelectronic medicine. To test the system, we have focused on the cardio-respiratory oscillators in the medulla oblongata that modulate heart rate in phase with respiration to induce respiratory sinus arrhythmia (RSA). We describe here a novel, scalable hCPG comprising physiologically realistic (Hodgkin–Huxley type) neurones and synapses. Our hCPG comprises two neurones that antagonise each other to provide rhythmic motor drive to the vagus nerve to slow the heart. We show how recent advances in modelling allow the motor output to adapt to physiological feedback such as respiration. In rats, we report on the restoration of RSA using an hCPG that receives diaphragmatic electromyography input and use it to stimulate the vagus nerve at specific time points of the respiratory cycle to slow the heart rate. We have validated the adaptation of stimulation to alterations in respiratory rate. We demonstrate that the hCPG is tuneable in terms of the depth and timing of the RSA relative to respiratory phase. These pioneering studies will now permit an analysis of the physiological role of RSA as well as its any potential therapeutic use in cardiac disease. PMID:25433077

Adaptive divergence in a scleractinian coral: physiological adaptation of Seriatopora hystrix to shallow and deep reef habitats

PubMed Central

2011-01-01

Background Divergent natural selection across environmental gradients has been acknowledged as a major driver of population and species divergence, however its role in the diversification of scleractinian corals remains poorly understood. Recently, it was demonstrated that the brooding coral Seriatopora hystrix and its algal endosymbionts (Symbiodinium) are genetically partitioned across reef environments (0-30 m) on the far northern Great Barrier Reef. Here, we explore the potential mechanisms underlying this differentiation and assess the stability of host-symbiont associations through a reciprocal transplantation experiment across habitats ('Back Reef', 'Upper Slope' and 'Deep Slope'), in combination with molecular (mtDNA and ITS2-DGGE) and photo-physiological analyses (respirometry and HPLC). Results The highest survival rates were observed for native transplants (measured 14 months after transplantation), indicating differential selective pressures between habitats. Host-symbiont assemblages remained stable during the experimental duration, demonstrating that the ability to "shuffle" or "switch" symbionts is restricted in S. hystrix. Photo-physiological differences were observed between transplants originating from the shallow and deep habitats, with indirect evidence of an increased heterotrophic capacity in native deep-water transplants (from the 'Deep Slope' habitat). Similar photo-acclimatisation potential was observed between transplants originating from the two shallow habitats ('Back Reef' and 'Upper Slope'), highlighting that their genetic segregation over depth may be due to other, non-photo-physiological traits under selection. Conclusions This study confirms that the observed habitat partitioning of S. hystrix (and associated Symbiodinium) is reflective of adaptive divergence along a depth gradient. Gene flow appears to be reduced due to divergent selection, highlighting the potential role of ecological mechanisms, in addition to physical dispersal barriers, in the diversification of scleractinian corals and their associated Symbiodinium. PMID:22004364

Effect of mandibular distraction osteogenesis on the temporomandibular joint: a systematic review of animal experimental studies.

PubMed

Andersen, Kristian; Pedersen, Thomas Klit; Hauge, Ellen Margrethe; Schou, Søren; Nørholt, Sven Erik

2014-04-01

The present systematic review aimed to test the hypothesis of no effect of mandibular distraction osteogenesis on the temporomandibular joint. Animal experimental studies from January 1985 to August 2013 were included. Studies were searched in PubMed, Embase, Scopus, and the Cochrane Library. A total of 289 articles were identified, and 17 were included. Included studies were characterized by a high risk of bias and by inhomogeneity related to animal species, experimental procedures, and evaluation methods. Mandibular distraction osteogenesis within physiologic limits may be followed by adaptive changes in bone, disk, and cartilage. Increased daily rates and total activation length may influence the severity of the adaptive changes. Animal experimental studies indicate that mandibular distraction osteogenesis may induce adaptive changes in the temporomandibular joint. Adaptive changes may be influenced by increased daily rates and total length of distraction osteogenesis. Well-designed studies are needed before final conclusions can be drawn. Copyright © 2014 Elsevier Inc. All rights reserved.

A Case for Hypogravity Studies Aboard ISS

NASA Technical Reports Server (NTRS)

Paloski, William H.

2014-01-01

Future human space exploration missions being contemplated by NASA and other spacefaring nations include some that would require long stays upon bodies having gravity levels much lower than that of Earth. While we have been able to quantify the physiological effects of sustained exposure to microgravity during various spaceflight programs over the past half-century, there has been no opportunity to study the physiological adaptations to gravity levels between zero-g and one-g. We know now that the microgravity environment of spaceflight drives adaptive responses of the bone, muscle, cardiovascular, and sensorimotor systems, causing bone demineralization, muscle atrophy, reduced aerobic capacity, motion sickness, and malcoordination. All of these outcomes can affect crew health and performance, particularly after return to a one-g environment. An important question for physicians, scientists, and mission designers planning human exploration missions to Mars (3/8 g), the Moon (1/6 g), or asteroids (likely negligible g) is: What protection can be expected from gravitational levels between zero-g and one-g? Will crewmembers deconditioned by six months of microgravity exposure on their way to Mars experience continued deconditioning on the Martian surface? Or, will the 3/8 g be sufficient to arrest or even reverse these adaptive changes? The implications for countermeasure deployment, habitat accommodations, and mission design warrant further investigation into the physiological responses to hypogravity. It is not possible to fully simulate hypogravity exposure on Earth for other than transient episodes (e.g., parabolic flight). However, it would be possible to do so in low Earth orbit (LEO) using the centrifugal forces produced in a live-aboard centrifuge. As we're not likely to launch a rotating human spacecraft into LEO anytime in the near future, we could take advantage of rodent subjects aboard the ISS if we had a centrifuge that could accommodate the rodent subjects for extended periods (weeks to months) at various hypogravity levels. Experiments aboard such a centrifuge could provide important insight into human exploration questions and simultaneously answer fundamental questions in gravitational physiology.

Modeling Diet-Induced Obesity with Obesity-Prone Rats: Implications for Studies in Females

PubMed Central

Giles, Erin D.; Jackman, Matthew R.; MacLean, Paul S.

2016-01-01

Obesity is a worldwide epidemic, and the comorbidities associated with obesity are numerous. Over the last two decades, we and others have employed an outbred rat model to study the development and persistence of obesity, as well as the metabolic complications that accompany excess weight. In this review, we summarize the strengths and limitations of this model and how it has been applied to further our understanding of human physiology in the context of weight loss and weight regain. We also discuss how the approach has been adapted over time for studies in females and female-specific physiological conditions, such as menopause and breast cancer. As excess weight and the accompanying metabolic complications have become common place in our society, we expect that this model will continue to provide a valuable translational tool to establish physiologically relevant connections to the basic science studies of obesity and body weight regulation. PMID:27933296

[Clinico-biochemical aspects of human adaptation in central Antarctica as applied to the problems of space biology and medicine].

PubMed

Kurbanov, V V; Khmel'kov, V P; Krupina, T N; Kuznetscv, A G; Kuz'min, M P

1977-01-01

The paper presents the results of clinical, physiological and biochemical examination of 27 polar explorer--members of the 17th Soviet Antartic Expedition at the Vostok station. It gives data on the morbidity rate and describes the development of the asthenic-neurotic syndrome. On the basis of studies of catecholamines and serotonin, the role of the sympatho-adrenal system in the human adaptation to the harsh environments of the Central Antarctica has been shown.

Physiology can contribute to better understanding, management, and conservation of coral reef fishes.

PubMed

Illing, Björn; Rummer, Jodie L

2017-01-01

Coral reef fishes, like many other marine organisms, are affected by anthropogenic stressors such as fishing and pollution and, owing to climate change, are experiencing increasing water temperatures and ocean acidification. Against the backdrop of these various stressors, a mechanistic understanding of processes governing individual organismal performance is the first step for identifying drivers of coral reef fish population dynamics. In fact, physiological measurements can help to reveal potential cause-and-effect relationships and enable physiologists to advise conservation management by upscaling results from cellular and individual organismal levels to population levels. Here, we highlight studies that include physiological measurements of coral reef fishes and those that give advice for their conservation. A literature search using combined physiological, conservation and coral reef fish key words resulted in ~1900 studies, of which only 99 matched predefined requirements. We observed that, over the last 20 years, the combination of physiological and conservation aspects in studies on coral reef fishes has received increased attention. Most of the selected studies made their physiological observations at the whole organism level and used their findings to give conservation advice on population dynamics, habitat use or the potential effects of climate change. The precision of the recommendations differed greatly and, not surprisingly, was least concrete when studies examined the effects of projected climate change scenarios. Although more and more physiological studies on coral reef fishes include conservation aspects, there is still a lack of concrete advice for conservation managers, with only very few published examples of physiological findings leading to improved management practices. We conclude with a call to action to foster better knowledge exchange between natural scientists and conservation managers to translate physiological findings more effectively in order to obtain evidence-based and adaptive management strategies for the conservation of coral reef fishes.

[Pregnancy in the context of general adaptation syndrome].

PubMed

Gur'ianov, V A; Pyregov, A V; Tolmachev, G N; Volodin, A V

2007-01-01

Based on their own findings and the data available in the literature on pregnancy including that complicated by gestosis, the authors consider these conditions in the context of Selye's general adaptation syndrome. They identify its basic links (the autonomic nervous and cardiovascular systems) the function of which is affected by all the physiological and pathophysiological processes involved in its development. There is a high likelihood of baseline impaired adaption processes in these links, which may lead to an inability to accommodate (dysadaptation) by the moment of delivery. The paper gives the current interpretation of functional disorders, called Zangemeister'a triad in 1913, from the present-day points of view of the evaluation of pregnancy as the systemic inflammatory response syndrome and, probably, adaptation disease. Based on the results of analyzing the data available in the literature, the authors indicate physiologically the basic trends in the modulation of impaired development processes of the general adaptation syndrome towards the completion of pregnancy and surgical delivery.

Camelid genomes reveal evolution and adaptation to desert environments.

PubMed

Wu, Huiguang; Guang, Xuanmin; Al-Fageeh, Mohamed B; Cao, Junwei; Pan, Shengkai; Zhou, Huanmin; Zhang, Li; Abutarboush, Mohammed H; Xing, Yanping; Xie, Zhiyuan; Alshanqeeti, Ali S; Zhang, Yanru; Yao, Qiulin; Al-Shomrani, Badr M; Zhang, Dong; Li, Jiang; Manee, Manee M; Yang, Zili; Yang, Linfeng; Liu, Yiyi; Zhang, Jilin; Altammami, Musaad A; Wang, Shenyuan; Yu, Lili; Zhang, Wenbin; Liu, Sanyang; Ba, La; Liu, Chunxia; Yang, Xukui; Meng, Fanhua; Wang, Shaowei; Li, Lu; Li, Erli; Li, Xueqiong; Wu, Kaifeng; Zhang, Shu; Wang, Junyi; Yin, Ye; Yang, Huanming; Al-Swailem, Abdulaziz M; Wang, Jun

2014-10-21

Bactrian camel (Camelus bactrianus), dromedary (Camelus dromedarius) and alpaca (Vicugna pacos) are economically important livestock. Although the Bactrian camel and dromedary are large, typically arid-desert-adapted mammals, alpacas are adapted to plateaus. Here we present high-quality genome sequences of these three species. Our analysis reveals the demographic history of these species since the Tortonian Stage of the Miocene and uncovers a striking correlation between large fluctuations in population size and geological time boundaries. Comparative genomic analysis reveals complex features related to desert adaptations, including fat and water metabolism, stress responses to heat, aridity, intense ultraviolet radiation and choking dust. Transcriptomic analysis of Bactrian camels further reveals unique osmoregulation, osmoprotection and compensatory mechanisms for water reservation underpinned by high blood glucose levels. We hypothesize that these physiological mechanisms represent kidney evolutionary adaptations to the desert environment. This study advances our understanding of camelid evolution and the adaptation of camels to arid-desert environments.

Adaptive regulation of sparseness by feedforward inhibition

PubMed Central

Assisi, Collins; Stopfer, Mark; Laurent, Gilles; Bazhenov, Maxim

2014-01-01

In the mushroom body of insects, odors are represented by very few spikes in a small number of neurons, a highly efficient strategy known as sparse coding. Physiological studies of these neurons have shown that sparseness is maintained across thousand-fold changes in odor concentration. Using a realistic computational model, we propose that sparseness in the olfactory system is regulated by adaptive feedforward inhibition. When odor concentration changes, feedforward inhibition modulates the duration of the temporal window over which the mushroom body neurons may integrate excitatory presynaptic input. This simple adaptive mechanism could maintain the sparseness of sensory representations across wide ranges of stimulus conditions. PMID:17660812

Global Transcriptional, Physiological, and Metabolite Analyses of the Responses of Desulfovibrio vulgaris Hildenborough to Salt Adaptation ▿ †

PubMed Central

He, Zhili; Zhou, Aifen; Baidoo, Edward; He, Qiang; Joachimiak, Marcin P.; Benke, Peter; Phan, Richard; Mukhopadhyay, Aindrila; Hemme, Christopher L.; Huang, Katherine; Alm, Eric J.; Fields, Matthew W.; Wall, Judy; Stahl, David; Hazen, Terry C.; Keasling, Jay D.; Arkin, Adam P.; Zhou, Jizhong

2010-01-01

The response of Desulfovibrio vulgaris Hildenborough to salt adaptation (long-term NaCl exposure) was examined by performing physiological, global transcriptional, and metabolite analyses. Salt adaptation was reflected by increased expression of genes involved in amino acid biosynthesis and transport, electron transfer, hydrogen oxidation, and general stress responses (e.g., heat shock proteins, phage shock proteins, and oxidative stress response proteins). The expression of genes involved in carbon metabolism, cell growth, and phage structures was decreased. Transcriptome profiles of D. vulgaris responses to salt adaptation were compared with transcriptome profiles of D. vulgaris responses to salt shock (short-term NaCl exposure). Metabolite assays showed that glutamate and alanine accumulated under salt adaptation conditions, suggesting that these amino acids may be used as osmoprotectants in D. vulgaris. Addition of amino acids (glutamate, alanine, and tryptophan) or yeast extract to the growth medium relieved salt-related growth inhibition. A conceptual model that links the observed results to currently available knowledge is proposed to increase our understanding of the mechanisms of D. vulgaris adaptation to elevated NaCl levels. PMID:20038696

[Stress-induced cellular adaptive mutagenesis].

PubMed

Zhu, Linjiang; Li, Qi

2014-04-01

The adaptive mutations exist widely in the evolution of cells, such as antibiotic resistance mutations of pathogenic bacteria, adaptive evolution of industrial strains, and cancerization of human somatic cells. However, how these adaptive mutations are generated is still controversial. Based on the mutational analysis models under the nonlethal selection conditions, stress-induced cellular adaptive mutagenesis is proposed as a new evolutionary viewpoint. The hypothetic pathway of stress-induced mutagenesis involves several intracellular physiological responses, including DNA damages caused by accumulation of intracellular toxic chemicals, limitation of DNA MMR (mismatch repair) activity, upregulation of general stress response and activation of SOS response. These responses directly affect the accuracy of DNA replication from a high-fidelity manner to an error-prone one. The state changes of cell physiology significantly increase intracellular mutation rate and recombination activity. In addition, gene transcription under stress condition increases the instability of genome in response to DNA damage, resulting in transcription-associated DNA mutagenesis. In this review, we summarize these two molecular mechanisms of stress-induced mutagenesis and transcription-associated DNA mutagenesis to help better understand the mechanisms of adaptive mutagenesis.

Ice age fish in a warming world: minimal variation in thermal acclimation capacity among lake trout (Salvelinus namaycush) populations

PubMed Central

Kelly, Nicholas I.; Burness, Gary; McDermid, Jenni L.; Wilson, Chris C.

2014-01-01

In the face of climate change, the persistence of cold-adapted species will depend on their adaptive capacity for physiological traits within and among populations. The lake trout (Salvelinus namaycush) is a cold-adapted salmonid and a relict from the last ice age that is well suited as a model species for studying the predicted effects of climate change on coldwater fishes. We investigated the thermal acclimation capacity of upper temperature resistance and metabolism of lake trout from four populations across four acclimation temperatures. Individuals were reared from egg fertilization onward in a common environment and, at 2 years of age, were acclimated to 8, 11, 15 or 19°C. Although one population had a slightly higher maximal metabolic rate (MMR), higher metabolic scope for activity and faster metabolic recovery across all temperatures, there was no interpopulation variation for critical thermal maximum (CTM) or routine metabolic rate (RMR) or for the thermal acclimation capacity of CTM, RMR, MMR or metabolic scope. Across the four acclimation temperatures, there was a 3°C maximal increase in CTM and 3-fold increase in RMR for all populations. Above 15°C, a decline in MMR and increase in RMR resulted in sharply reduced metabolic scope for all populations acclimated at 19°C. Together, these data suggest there is limited variation among lake trout populations in thermal physiology or capacity for thermal acclimatization, and that climate change may impact lake trout populations in a similar manner across a wide geographical range. Understanding the effect of elevated temperatures on the thermal physiology of this economically and ecologically important cold-adapted species will help inform management and conservation strategies for the long-term sustainability of lake trout populations. PMID:27293646

Does smooth muscle in an intact airway undergo length adaptation during a sustained change in transmural pressure?

PubMed

Ansell, Thomas K; McFawn, Peter K; McLaughlin, Robert A; Sampson, David D; Eastwood, Peter R; Hillman, David R; Mitchell, Howard W; Noble, Peter B

2015-03-01

In isolated airway smooth muscle (ASM) strips, an increase or decrease in ASM length away from its current optimum length causes an immediate reduction in force production followed by a gradual time-dependent recovery in force, a phenomenon termed length adaptation. In situ, length adaptation may be initiated by a change in transmural pressure (Ptm), which is a primary physiological determinant of ASM length. The present study sought to determine the effect of sustained changes in Ptm and therefore, ASM perimeter, on airway function. We measured contractile responses in whole porcine bronchial segments in vitro before and after a sustained inflation from a baseline Ptm of 5 cmH2O to 25 cmH2O, or deflation to -5 cmH2O, for ∼50 min in each case. In one group of airways, lumen narrowing and stiffening in response to electrical field stimulation (EFS) were assessed from volume and pressure signals using a servo-controlled syringe pump with pressure feedback. In a second group of airways, lumen narrowing and the perimeter of the ASM in situ were determined by anatomical optical coherence tomography. In a third group of airways, active tension was determined under isovolumic conditions. Both inflation and deflation reduced the contractile response to EFS. Sustained Ptm change resulted in a further decrease in contractile response, which returned to baseline levels upon return to the baseline Ptm. These findings reaffirm the importance of Ptm in regulating airway narrowing. However, they do not support a role for ASM length adaptation in situ under physiological levels of ASM lengthening and shortening. Copyright © 2015 the American Physiological Society.

Periodontal Ligament Entheses and their Adaptive Role in the Context of Dentoalveolar Joint Function

PubMed Central

Lin, Jeremy D.; Jang, Andrew T.; Kurylo, Michael P.; Hurng, Jonathan; Yang, Feifei; Yang, Lynn; Pal, Arvin; Chen, Ling; Ho, Sunita P.

2017-01-01

Objectives The dynamic bone-periodontal ligament (PDL)-tooth fibrous joint consists of two adaptive functionally graded interfaces (FGI), the PDL-bone and PDL-cementum that respond to mechanical strain transmitted during mastication. In general, from a materials and mechanics perspective, FGI prevent catastrophic failure during prolonged cyclic loading. This review is a discourse of results gathered from literature to illustrate the dynamic adaptive nature of the fibrous joint in response to physiologic and pathologic simulated functions, and experimental tooth movement. Methods Historically, studies have investigated soft to hard tissue transitions through analytical techniques that provided insights into structural, biochemical, and mechanical characterization methods. Experimental approaches included two dimensional to three dimensional advanced in situ imaging and analytical techniques. These techniques allowed mapping and correlation of deformations to physicochemical and mechanobiological changes within volumes of the complex subjected to concentric and eccentric loading regimes respectively. Results Tooth movement is facilitated by mechanobiological activity at the interfaces of the fibrous joint and generates elastic discontinuities at these interfaces in response to eccentric loading. Both concentric and eccentric loads mediated cellular responses to strains, and prompted self-regulating mineral forming and resorbing zones that in turn altered the functional space of the joint. Significance A multiscale biomechanics and mechanobiology approach is important for correlating joint function to tissue-level strain-adaptive properties with overall effects on joint form as related to physiologic and pathologic functions. Elucidating the shift in localization of biomolecules specifically at interfaces during development, function, and therapeutic loading of the joint is critical for developing “functional regeneration and adaptation” strategies with an emphasis on restoring physiologic joint function. PMID:28476202

De novo assembly and characterization of tissue specific transcriptomes in the emerald notothen, Trematomus bernacchii.

PubMed

Huth, Troy J; Place, Sean P

2013-11-20

The notothenioids comprise a diverse group of fishes that rapidly radiated after isolation by the Antarctic Circumpolar Current approximately 14-25 million years ago. Given that evolutionary adaptation has led to finely tuned traits with narrow physiological limits in these organisms, this system provides a unique opportunity to examine physiological trade-offs and limits of adaptive responses to environmental perturbation. As such, notothenioids have a rich history with respect to studies attempting to understand the vulnerability of polar ecosystems to the negative impacts associated with global climate change. Unfortunately, despite being a model system for understanding physiological adaptations to extreme environments, we still lack fundamental molecular tools for much of the Nototheniidae family. Specimens of the emerald notothen, Trematomus bernacchii, were acclimated for 28 days in flow-through seawater tanks maintained near ambient seawater temperatures (-1.5°C) or at +4°C. Following acclimation, tissue specific cDNA libraries for liver, gill and brain were created by pooling RNA from n = 5 individuals per temperature treatment. The tissue specific libraries were bar-coded and used for 454 pyrosequencing, which yielded over 700 thousand sequencing reads. A de novo assembly and annotation of these reads produced a functional transcriptome library of T. bernacchii containing 30,107 unigenes, 13,003 of which possessed significant homology to a known protein product. Digital gene expression analysis of these extremely cold adapted fish reinforced the loss of an inducible heat shock response and allowed the preliminary exploration into other elements of the cellular stress response. Preliminary exploration of the transcriptome of T. bernacchii under elevated temperatures enabled a semi-quantitative comparison to prior studies aimed at characterizing the thermal response of this endemic fish whose size, abundance and distribution has established it as a pivotal species in polar research spanning several decades. The comparison of these findings to previous studies demonstrates the efficacy of transcriptomics and digital gene expression analysis as tools in future studies of polar organisms and has greatly increased the available genomic resources for the suborder Notothenioidei, particularly in the Trematominae subfamily.

Effect of walking stress on growth, physiological adaptability and endocrine responses in Malpura ewes in a semi-arid tropical environment

NASA Astrophysics Data System (ADS)

Sejian, Veerasamy; Maurya, Vijai P.; Naqvi, Syed M. K.

2012-03-01

Sheep in hot semi-arid environments are mostly reared using extensive systems. In addition to thermal stress and feed scarcity, the animals need to walk long distances for grazing in this ecological zone. A study was conducted to assess the effect of long-distance walking on adaptive capability in terms of physiological, biochemical and endocrine responses in Malpura ewes. Fourteen adult Malpura non-pregnant ewes weighing between 33 and 35 kg were used in the study. The ewes were randomly allocated into two groups of seven animals each: GI ( n = 7; Control), and GII ( n = 7; walking stress). The animals were stall-fed with a diet consisting of 70% roughage and 30% concentrate. Both GI and GII ewes had uniform access to feed and water. The walking stress group (GII) ewes were made to walk 14 km in two spans between 0900 and 1500 hours with 1 h 30 min for each span (7 km) of walking. The ewes subjected to walking stress (GII) were prevented from grazing by applying a face mask made of cotton thread. The study was conducted for a period of two estrous cycles (35 days) during the autumn season (October-November). Physiological responses were recorded twice daily at 0800 and 1400 hours at weekly intervals. Blood samples were collected from the jugular vein at weekly intervals to study the effects of walking stress on blood biochemical and endocrine parameters. The results indicate that walking stress had significant ( P < 0.05) influence on body weight, average daily gain, respiration rate (RR), rectal temperature (RT), haemoglobin (Hb), packed cell volume (PCV), plasma glucose, calcium, phosphorus, aspartate amino transferase (AST), alanine amino transferase (ALT), tri-iodo-thyronine (T3), thyroxin (T4), and cortisol. However, walking stress did not influence the reproductive hormone levels. The significant changes in RR, RT, plasma cortisol, T3 and T4 show that Malpura ewes have the capability to adapt to long-distance walking, and that adrenal and thyroid gland hormones play a significant role in such adaptation.

De novo assembly and characterization of tissue specific transcriptomes in the emerald notothen, Trematomus bernacchii

PubMed Central

2013-01-01

Background The notothenioids comprise a diverse group of fishes that rapidly radiated after isolation by the Antarctic Circumpolar Current approximately 14–25 million years ago. Given that evolutionary adaptation has led to finely tuned traits with narrow physiological limits in these organisms, this system provides a unique opportunity to examine physiological trade-offs and limits of adaptive responses to environmental perturbation. As such, notothenioids have a rich history with respect to studies attempting to understand the vulnerability of polar ecosystems to the negative impacts associated with global climate change. Unfortunately, despite being a model system for understanding physiological adaptations to extreme environments, we still lack fundamental molecular tools for much of the Nototheniidae family. Results Specimens of the emerald notothen, Trematomus bernacchii, were acclimated for 28 days in flow-through seawater tanks maintained near ambient seawater temperatures (−1.5°C) or at +4°C. Following acclimation, tissue specific cDNA libraries for liver, gill and brain were created by pooling RNA from n = 5 individuals per temperature treatment. The tissue specific libraries were bar-coded and used for 454 pyrosequencing, which yielded over 700 thousand sequencing reads. A de novo assembly and annotation of these reads produced a functional transcriptome library of T. bernacchii containing 30,107 unigenes, 13,003 of which possessed significant homology to a known protein product. Digital gene expression analysis of these extremely cold adapted fish reinforced the loss of an inducible heat shock response and allowed the preliminary exploration into other elements of the cellular stress response. Conclusions Preliminary exploration of the transcriptome of T. bernacchii under elevated temperatures enabled a semi-quantitative comparison to prior studies aimed at characterizing the thermal response of this endemic fish whose size, abundance and distribution has established it as a pivotal species in polar research spanning several decades. The comparison of these findings to previous studies demonstrates the efficacy of transcriptomics and digital gene expression analysis as tools in future studies of polar organisms and has greatly increased the available genomic resources for the suborder Notothenioidei, particularly in the Trematominae subfamily. PMID:24252228

Genome and Transcriptome Analyses Provide Insight into the Euryhaline Adaptation Mechanism of Crassostrea gigas

PubMed Central

Zhang, Linlin; Li, Chunyan; Li, Li; She, Zhicai; Huang, Baoyu; Zhang, Guofan

2013-01-01

Background The Pacific oyster, Crassostrea gigas, has developed special mechanisms to regulate its osmotic balance to adapt to fluctuations of salinities in coastal zones. To understand the oyster’s euryhaline adaptation, we analyzed salt stress effectors metabolism pathways under different salinities (salt 5, 10, 15, 20, 25, 30 and 40 for 7 days) using transcriptome data, physiology experiment and quantitative real-time PCR. Results Transcriptome data uncovered 189, 480, 207 and 80 marker genes for monitoring physiology status of oysters and the environment conditions. Three known salt stress effectors (involving ion channels, aquaporins and free amino acids) were examined. The analysis of ion channels and aquaporins indicated that 7 days long-term salt stress inhibited voltage-gated Na+/K+ channel and aquaporin but increased calcium-activated K+ channel and Ca2+ channel. As the most important category of osmotic stress effector, we analyzed the oyster FAAs metabolism pathways (including taurine, glycine, alanine, beta-alanine, proline and arginine) and explained FAAs functional mechanism for oyster low salinity adaptation. FAAs metabolism key enzyme genes displayed expression differentiation in low salinity adapted individuals comparing with control which further indicated that FAAs played important roles for oyster salinity adaptation. A global metabolic pathway analysis (iPath) of oyster expanded genes displayed a co-expansion of FAAs metabolism in C. gigas compared with seven other species, suggesting oyster’s powerful ability regarding FAAs metabolism, allowing it to adapt to fluctuating salinities, which may be one important mechanism underlying euryhaline adaption in oyster. Additionally, using transcriptome data analysis, we uncovered salt stress transduction networks in C. gigas. Conclusions Our results represented oyster salt stress effectors functional mechanisms under salt stress conditions and explained the expansion of FAAs metabolism pathways as the most important effectors for oyster euryhaline adaptation. This study was the first to explain oyster euryhaline adaptation at a genome-wide scale in C. gigas. PMID:23554902

The maternal social environment shapes offspring growth, physiology, and behavioural phenotype in guinea pigs.

PubMed

von Engelhardt, Nikolaus; Kowalski, Gabriele J; Guenther, Anja

2015-01-01

Prenatal conditions influence offspring development in many species. In mammals, the effects of social density have traditionally been considered a detrimental form of maternal stress. Now their potential adaptive significance is receiving greater attention.Sex-specific effects of maternal social instability on offspring in guinea pigs (Cavia aperea f. porcellus) have been interpreted as adaptations to high social densities, while the effects of low social density are unknown. Hence, we compared morphological, behavioural and physiological development between offspring born to mothers housed either individually or in groups during the second half of pregnancy. Females housed individually and females housed in groups gave birth to litters of similar size and sex-ratios, and there were no differences in birth weight. Sons of individually-housed mothers grew faster than their sisters, whereas daughters ofgroup-housed females grew faster than their brothers, primarily due to an effect on growth of daughters. There were few effects on offspring behaviour. Baseline cortisol levels in saliva of pups on day 1 and day 7 were not affected, but we saw a blunted cortisol response to social separation on day 7 in sons of individually-housed females and daughters of group-housed females. The effects were consistent across two replicate experiments. The observed effects only partially support the adaptive hypothesis. Increased growth of daughters may be adaptive under high densities due to increasedfemale competition, but it is unclear why growth of sons is not increased under low social densities when males face less competition from older, dominant males. The differences in growth may be causally linked to sex-specific effects on cortisol response, although individual cortisol response and growth were not correlated, and various other mechanisms are possible. The observed sex-specific effects on early development are intriguing, yet the potential adaptive benefits and physiological mechanisms require further study.

Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms.

PubMed

Liu, Tsung-Li; Upadhyayula, Srigokul; Milkie, Daniel E; Singh, Ved; Wang, Kai; Swinburne, Ian A; Mosaliganti, Kishore R; Collins, Zach M; Hiscock, Tom W; Shea, Jamien; Kohrman, Abraham Q; Medwig, Taylor N; Dambournet, Daphne; Forster, Ryan; Cunniff, Brian; Ruan, Yuan; Yashiro, Hanako; Scholpp, Steffen; Meyerowitz, Elliot M; Hockemeyer, Dirk; Drubin, David G; Martin, Benjamin L; Matus, David Q; Koyama, Minoru; Megason, Sean G; Kirchhausen, Tom; Betzig, Eric

2018-04-20

True physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo. The technology reveals the phenotypic diversity within cells across different organisms and developmental stages and may offer insights into how cells harness their intrinsic variability to adapt to different physiological environments. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

[The adaptive pharmacological correction of functional disorders in young recruits with hypotrophy].

PubMed

Buchnov, A D; Grechko, A T; Murga, Ia T

2000-04-01

Low level of physical development, physiologic reserves, signs of psychical disadaptation, frequent functional disorders in cardiovascular system and gastrointestinal tract are noted in recruits with hypotrophy. Using of rapidly acting adaptogenes during 1 month (phytopreparation elixir "Altai" and "Vitavis" in tablets) significantly improves body state: increase in the level of physiologic reserves, physical working capacity, IMT, body unspecific resistance; improvement in indices of hemodynamics, metabolism and immunity; decrease in asthenization and psychical disadaptation. The state of adaptation and increased resistance in this recruit group remains during the following months of service.

Frequency of infant stroking reported by mothers moderates the effect of prenatal depression on infant behavioural and physiological outcomes.

PubMed

Sharp, Helen; Pickles, Andrew; Meaney, Michael; Marshall, Kate; Tibu, Florin; Hill, Jonathan

2012-01-01

Animal studies find that prenatal stress is associated with increased physiological and emotional reactivity later in life, mediated via fetal programming of the HPA axis through decreased glucocorticoid receptor (GR) gene expression. Post-natal behaviours, notably licking and grooming in rats, cause decreased behavioural indices of fear and reduced HPA axis reactivity mediated via increased GR gene expression. Post-natal maternal behaviours may therefore be expected to modify prenatal effects, but this has not previously been examined in humans. We examined whether, according to self-report, maternal stroking over the first weeks of life modified associations between prenatal depression and physiological and behavioral outcomes in infancy, hence mimicking effects of rodent licking and grooming. From a general population sample of 1233 first time mothers recruited at 20 weeks gestation we drew a stratified random sample of 316 for assessment at 32 weeks based on reported inter-partner psychological abuse, a risk to child development. Of these 271 provided data at 5, 9 and 29 weeks post delivery. Mothers reported how often they stroked their babies at 5 and 9 weeks. At 29 weeks vagal withdrawal to a stressor, a measure of physiological adaptability, and maternal reported negative emotionality were assessed. There was a significant interaction between prenatal depression and maternal stroking in the prediction of vagal reactivity to a stressor (p = .01), and maternal reports of infant anger proneness (p = .007) and fear (p = .043). Increasing maternal depression was associated with decreasing physiological adaptability, and with increasing negative emotionality, only in the presence of low maternal stroking. These initial findings in humans indicate that maternal stroking in infancy, as reported by mothers, has effects strongly resembling the effects of observed maternal behaviours in animals, pointing to future studies of the epigenetic, physiological and behavioral effects of maternal stroking.

PHYCAA+: an optimized, adaptive procedure for measuring and controlling physiological noise in BOLD fMRI.

PubMed

Churchill, Nathan W; Strother, Stephen C

2013-11-15

The presence of physiological noise in functional MRI can greatly limit the sensitivity and accuracy of BOLD signal measurements, and produce significant false positives. There are two main types of physiological confounds: (1) high-variance signal in non-neuronal tissues of the brain including vascular tracts, sinuses and ventricles, and (2) physiological noise components which extend into gray matter tissue. These physiological effects may also be partially coupled with stimuli (and thus the BOLD response). To address these issues, we have developed PHYCAA+, a significantly improved version of the PHYCAA algorithm (Churchill et al., 2011) that (1) down-weights the variance of voxels in probable non-neuronal tissue, and (2) identifies the multivariate physiological noise subspace in gray matter that is linked to non-neuronal tissue. This model estimates physiological noise directly from EPI data, without requiring external measures of heartbeat and respiration, or manual selection of physiological components. The PHYCAA+ model significantly improves the prediction accuracy and reproducibility of single-subject analyses, compared to PHYCAA and a number of commonly-used physiological correction algorithms. Individual subject denoising with PHYCAA+ is independently validated by showing that it consistently increased between-subject activation overlap, and minimized false-positive signal in non gray-matter loci. The results are demonstrated for both block and fast single-event task designs, applied to standard univariate and adaptive multivariate analysis models. Copyright © 2013 Elsevier Inc. All rights reserved.

[Functional state of various physiological systems of the human body during respiration of neon-oxygen mixture at depth up to 400 meters].

PubMed

Poleshuk, I P; Genin, A M; Unku, R D; Mikhnenko, A E; Sementsov, V N; Suvorov, A V

1991-01-01

Hyperbaric neon-oxygen mixture has been studied for the effect of its high density under pressure of 41 ata on basic physiological functions of human organism. Typical changes of the cardiorespiratory system and tissue respiration parameters are revealed. Changes in physical working capacity are shown. Exposure to gaseous medium of high pressure and density is accompanied by the development of some compensatory-adaptive reactions. The possibility to perform mid-hard physical work is attained with overstrain of respiration and circulation function.

Anabolic Adaptations Occur in Conscripts During Basic Military Training Despite High Prevalence of Vitamin D Deficiency and Decrease in Iron Status.

PubMed

Ööpik, Vahur; Timpmann, Saima; Rips, Leho; Olveti, Indrek; Kõiv, Kersti; Mooses, Martin; Mölder, Hanno; Varblane, Ahti; Lille, Hele-Reet; Gapeyeva, Helena

2017-03-01

In Estonian Defense Forces that are drawn up on the basis of the conscription model considerable numbers of young men are prematurely discharged from military service for medical reasons, but causes leading to premature dropout of conscripts have not been systematically studied. However, one of the factors involved could be relatively demanding physical training that starts at the beginning of military service in the form of basic military training (BMT). Cumulative training and nontraining stresses experienced by conscripts during BMT may exceed their physiological adaptability and increase the probability of becoming prematurely discharged. Therefore, the primary purpose of this study was to assess physiological responses to 10-week BMT in Estonian conscripts. The protocol of the study confirmed to the standards set by the Declaration of Helsinki and it was approved by the Research Ethics Committee of the University of Tartu. Mean ± SD age and body mass index of 94 conscripts studied was 20.9 ± 1.7 years and 24.2 ± 3.0 kg · m -2 , respectively. Fasting venous blood analysis was performed four times during BMT (October to December) and once 15 weeks after the end of BMT (in March). One-factor (time) repeated measures analysis of variance was used to evaluate the differences within the variables. Statistical significance was set at p < 0.05. Where a significant main effect was observed, Tukey's honesty significant difference post-hoc analysis was used to locate differences between the means. A Pearson product moment coefficient of correlation (r) with α level set at 0.05 was applied to determine the relationship between variables. Significant increases in serum testosterone concentration (60.6%), testosterone to cortisol ratio (61.1%), blood erythrocyte count (4.3%), hemoglobin concentration (3.8%) and hematocrit (2.2%), and decrease in serum ferritin concentration (39.3%) occurred between weeks 1 and 10 during BMT (in all cases p < 0.0001). Fifteen weeks later, these parameters were still at increased or decreased levels, respectively, compared to week 1. The prevalence of vitamin D deficiency (serum 25(OH) D concentration <50 nmol · L -1 ) increased from 42.6% in week 1 to 80.8% in week 10 and to 91.5% 15 weeks later. Serum 25(OH)D levels did not correlate with testosterone concentrations (r = 0.062, p = 0.552 in Wk-1 and r = -0.079, p = 0.448 in Wk-25). These findings suggest that BMT induces anabolic physiological adaptations in conscripts despite vitamin D deficiency and decrease in iron status. However, high prevalence of vitamin D deficiency and decline in iron status may limit physiological adaptations and improvement in physical work capacity to a suboptimal level. Furthermore, as vitamin D influences a variety of functions important for health, deficiency in conscripts should be considered a major concern that needs treatment. An acknowledged limitation of the study is the lack of a control group of conscripts possessing normal vitamin D status and stable serum ferritin levels throughout the study period. Nevertheless, the research design employed enabled to determine two factors that potentially limit physiological adaptability of conscripts to military training loads in ecologically authentic environment. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

Life in a dark biosphere: a review of circadian physiology in "arrhythmic" environments.

PubMed

Beale, Andrew David; Whitmore, David; Moran, Damian

2016-12-01

Most of the life with which humans interact is exposed to highly rhythmic and extremely predictable changes in illumination that occur with the daily events of sunrise and sunset. However, while the influence of the sun feels omnipotent to surface dwellers such as ourselves, life on earth is dominated, in terms of biomass, by organisms isolated from the direct effects of the sun. A limited understanding of what life is like away from the sun can be inferred from our knowledge of physiology and ecology in the light biosphere, but a full understanding can only be gained by studying animals from the dark biosphere, both in the laboratory and in their natural habitats. One of the least understood aspects of life in the dark biosphere is the rhythmicity of physiology and what it means to live in an environment of low or no rhythmicity. Here we describe methods that may be used to understand rhythmic physiology in the dark and summarise some of the studies of rhythmic physiology in "arrhythmic" environments, such as the poles, deep sea and caves. We review what can be understood about the adaptive value of rhythmic physiology on the Earth's surface from studies of animals from arrhythmic environments and what role a circadian clock may play in the dark.

Adaptation problems with nursing home application for elderly persons: an application of the Roy adaptation nursing model.

PubMed

Farkas, L

1981-09-01

This study sought to identify adaptation problems on the part of elderly persons and significant others that were associated with nursing home applications for elderly persons. Within the framework of the Roy Adaptation Nursing Model, an ex post facto research design was utilized to identify these adaptation problems. The four adaptive modes in this model are: physiological, self-concept, role function, and interdependence. The study group (n = 22) and a control group of elderly persons living in Calgary, as well as their significant others, were administered a structured questionnaire. Five hypotheses relating to overall adaptation problems, powerlessness, role reversal, guilt, and knowledge and utilization of services were formulated and tested. Only the hypothesis indicating role reversal on the part of the significant others was accepted. Adaptation problems encountered by the elderly which were associated with nursing home applications occurred in the self-concept and interdependence adaptive modes. The adaptation problems perceived by the significant others, which were associated with nursing home applications for their elderly, occurred in the self-concept, role function, and interdependence modes. Adaptation problems from the significant others' perception rather than from the elderly persons' perception appear to be more significantly associated with nursing home applications.

Coadaptive aiding and automation enhance operator performance.

PubMed

Christensen, James C; Estepp, Justin R

2013-10-01

In this work, we expand on the theory of adaptive aiding by measuring the effectiveness of coadaptive aiding, wherein we explicitly allow for both system and user to adapt to each other. Adaptive aiding driven by psychophysiological monitoring has been demonstrated to be a highly effective means of controlling task allocation and system functioning. Psychophysiological monitoring is uniquely well suited for coadaptation, as malleable brain activity may be used as a continuous input to the adaptive system. To establish the efficacy of the coadaptive system, physiological activation of adaptation was directly compared with manual activation or no activation of the same automation and cuing systems. We used interface adaptations and automation that are plausible for real-world operations, presented in the context of a multi-remotely piloted aircraft control simulation. Each participant completed 3 days of testing during 1 week. Performance was assessed via proportion of targets successfully engaged. In the first 2 days of testing, there were no significant differences in performance between the conditions. However, in the third session, physiological adaptation produced the highest performance. By extending the data collection across multiple days, we offered enough time and repeated experience for user adaptation as well as online system adaptation, hence demonstrating coadaptive aiding. The results of this work may be employed to implement more effective adaptive workstations in a variety of work domains.

Modification of Motion Perception and Manual Control Following Short-Durations Spaceflight

NASA Technical Reports Server (NTRS)

Wood, S. J.; Vanya, R. D.; Esteves, J. T.; Rupert, A. H.; Clement, G.

2011-01-01

Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination and spatial disorientation following G-transitions. This ESA-NASA study was designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short-duration spaceflights. The goals of this study were to (1) examine the effects of stimulus frequency on adaptive changes in motion perception during passive tilt and translation motion, (2) quantify decrements in manual control of tilt motion, and (3) evaluate vibrotactile feedback as a sensorimotor countermeasure.

Intermittent cardiac overload results in adaptive hypertrophy and provides protection against left ventricular acute pressure overload insult.

PubMed

Moreira-Gonçalves, Daniel; Henriques-Coelho, Tiago; Fonseca, Hélder; Ferreira, Rita; Padrão, Ana Isabel; Santa, Cátia; Vieira, Sara; Silva, Ana Filipa; Amado, Francisco; Leite-Moreira, Adelino; Duarte, José Alberto

2015-09-01

The present study aimed to test whether a chronic intermittent workload could induce an adaptive cardiac phenotype Chronic intermittent workload induced features of adaptive hypertrophy This was paralleled by protection against acute pressure overload insult The heart may adapt favourably to balanced demands, regardless of the nature of the stimuli. The present study aimed to test whether submitting the healthy heart to intermittent and tolerable amounts of workload, independently of its nature, could result in an adaptive cardiac phenotype. Male Wistar rats were subjected to treadmill running (Ex) (n = 20), intermittent cardiac overload with dobutamine (ITO) (2 mg kg(-1) , s.c.; n = 20) or placebo administration (Cont) (n = 20) for 5 days week(-1) for 8 weeks. Animals were then killed for histological and biochemical analysis or subjected to left ventricular haemodynamic evaluation under baseline conditions, in response to isovolumetric contractions and to sustained LV acute pressure overload (35% increase in peak systolic pressure maintained for 2 h). Baseline cardiac function was enhanced only in Ex, whereas the response to isovolumetric heartbeats was improved in both ITO and Ex. By contrast to the Cont group, in which rats developed diastolic dysfunction with sustained acute pressure overload, ITO and Ex showed increased tolerance to this stress test. Both ITO and Ex developed cardiomyocyte hypertrophy without fibrosis, no overexpression of osteopontin-1 or β-myosin heavy chain, and increased expression of sarcoplasmic reticulum Ca(2+) protein. Regarding hypertrophic pathways, ITO and Ex showed activation of the protein kinase B/mammalian target of rapamycin pathway but not calcineurin. Mitochondrial complex IV and V activities were also increased in ITO and Ex. Chronic submission to controlled intermittent cardiac overload, independently of its nature, results in an adaptive cardiac phenotype. Features of the cardiac overload, such as the duration and magnitude of the stimuli, may play a role in the development of an adaptive or maladaptive phenotype. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Ultrasound in space

NASA Technical Reports Server (NTRS)

Martin, David S.; South, Donna A.; Garcia, Kathleen M.; Arbeille, Philippe

2003-01-01

Physiology of the human body in space has been a major concern for space-faring nations since the beginning of the space era. Ultrasound (US) is one of the most cost effective and versatile forms of medical imaging. As such, its use in characterizing microgravity-induced changes in physiology is being realized. In addition to the use of US in related ground-based studies, equipment has also been modified to fly in space. This involves alteration to handle the stresses of launch and different power and cooling requirements. Study protocols also have been altered to accommodate the microgravity environment. Ultrasound studies to date have shown a pattern of adaptation to microgravity that includes changes in cardiac chamber sizes and vertebral spacing. Ultrasound has been and will continue to be an important component in the investigation of physiological and, possibly, pathologic changes occurring in space or as a result of spaceflight.

How to Do It. Plant Eco-Physiology: Experiments on Crassulacean Acid Metabolism, Using Minimal Equipment.

ERIC Educational Resources Information Center

Friend, Douglas J. C.

1990-01-01

Features of Crassulacean Acid Metabolism plants are presented. Investigations of a complex eco-physiological plant adaptation to the problems of growth in an arid environment are discussed. Materials and procedures for these investigations are described. (CW)

Exercise does not enhance aged bone's impaired response to artificial loading in C57Bl/6 mice.

PubMed

Meakin, Lee B; Udeh, Chinedu; Galea, Gabriel L; Lanyon, Lance E; Price, Joanna S

2015-12-01

Bones adapt their structure to their loading environment and so ensure that they become, and are maintained, sufficiently strong to withstand the loads to which they are habituated. The effectiveness of this process declines with age and bones become fragile fracturing with less force. This effect in humans also occurs in mice which experience age-related bone loss and reduced adaptation to loading. Exercise engenders many systemic and local muscular physiological responses as well as engendering local bone strain. To investigate whether these physiological responses influence bones' adaptive responses to mechanical strain we examined whether a period of treadmill exercise influenced the adaptive response to an associated period of artificial loading in young adult (17-week) and old (19-month) mice. After treadmill acclimatization, mice were exercised for 30 min three times per week for two weeks. Three hours after each exercise period, right tibiae were subjected to 40 cycles of non-invasive axial loading engendering peak strain of 2250 με. In both young and aged mice exercise increased cross-sectional muscle area and serum sclerostin concentration. In young mice it also increased serum IGF1. Exercise did not affect bone's adaptation to loading in any measured parameter in young or aged bone. These data demonstrate that a level of exercise sufficient to cause systemic changes in serum, and adaptive changes in local musculature, has no effect on bone's response to loading 3h later. This study provides no support for the beneficial effects of exercise on bone in the elderly being mediated by systemic or local muscle-derived effects rather than local adaptation to altered mechanical strain. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Artificial gravity as a countermeasure for mitigating physiological deconditioning during long-duration space missions

PubMed Central

Clément, Gilles R.; Bukley, Angelia P.; Paloski, William H.

2015-01-01

In spite of the experience gained in human space flight since Yuri Gagarin’s historical flight in 1961, there has yet to be identified a completely effective countermeasure for mitigating the effects of weightlessness on humans. Were astronauts to embark upon a journey to Mars today, the 6-month exposure to weightlessness en route would leave them considerably debilitated, even with the implementation of the suite of piece-meal countermeasures currently employed. Continuous or intermittent exposure to simulated gravitational states on board the spacecraft while traveling to and from Mars, also known as artificial gravity, has the potential for enhancing adaptation to Mars gravity and re-adaptation to Earth gravity. Many physiological functions are adversely affected by the weightless environment of spaceflight because they are calibrated for normal, Earth’s gravity. Hence, the concept of artificial gravity is to provide a broad-spectrum replacement for the gravitational forces that naturally occur on the Earth’s surface, thereby avoiding the physiological deconditioning that takes place in weightlessness. Because researchers have long been concerned by the adverse sensorimotor effects that occur in weightlessness as well as in rotating environments, additional study of the complex interactions among sensorimotor and other physiological systems in rotating environments must be undertaken both on Earth and in space before artificial gravity can be implemented. PMID:26136665

Low-shear modeled microgravity: a global environmental regulatory signal affecting bacterial gene expression, physiology, and pathogenesis

NASA Technical Reports Server (NTRS)

Nickerson, Cheryl A.; Ott, C. Mark; Wilson, James W.; Ramamurthy, Rajee; LeBlanc, Carly L.; Honer zu Bentrup, Kerstin; Hammond, Timothy; Pierson, Duane L.

2003-01-01

Bacteria inhabit an impressive variety of ecological niches and must adapt constantly to changing environmental conditions. While numerous environmental signals have been examined for their effect on bacteria, the effects of mechanical forces such as shear stress and gravity have only been investigated to a limited extent. However, several important studies have demonstrated a key role for the environmental signals of low shear and/or microgravity in the regulation of bacterial gene expression, physiology, and pathogenesis [Chem. Rec. 1 (2001) 333; Appl. Microbiol. Biotechnol. 54 (2000) 33; Appl. Environ. Microbiol. 63 (1997) 4090; J. Ind. Microbiol. 18 (1997) 22; Curr. Microbiol. 34(4) (1997) 199; Appl. Microbiol. Biotechnol. 56(3-4) (2001) 384; Infect Immun. 68(6) (2000) 3147; Cell 109(7) (2002) 913; Appl. Environ. Microbiol. 68(11) (2002) 5408; Proc. Natl. Acad. Sci. U. S. A. 99(21) (2002) 13807]. The response of bacteria to these environmental signals, which are similar to those encountered during prokaryotic life cycles, may provide insight into bacterial adaptations to physiologically relevant conditions. This review focuses on the current and potential future research trends aimed at understanding the effect of the mechanical forces of low shear and microgravity analogues on different bacterial parameters. In addition, this review also discusses the use of microgravity technology to generate physiologically relevant human tissue models for research in bacterial pathogenesis.

A tissue adaptation model based on strain-dependent collagen degradation and contact-guided cell traction.

PubMed

Heck, T A M; Wilson, W; Foolen, J; Cilingir, A C; Ito, K; van Donkelaar, C C

2015-03-18

Soft biological tissues adapt their collagen network to the mechanical environment. Collagen remodeling and cell traction are both involved in this process. The present study presents a collagen adaptation model which includes strain-dependent collagen degradation and contact-guided cell traction. Cell traction is determined by the prevailing collagen structure and is assumed to strive for tensional homeostasis. In addition, collagen is assumed to mechanically fail if it is over-strained. Care is taken to use principally measurable and physiologically meaningful relationships. This model is implemented in a fibril-reinforced biphasic finite element model for soft hydrated tissues. The versatility and limitations of the model are demonstrated by corroborating the predicted transient and equilibrium collagen adaptation under distinct mechanical constraints against experimental observations from the literature. These experiments include overloading of pericardium explants until failure, static uniaxial and biaxial loading of cell-seeded gels in vitro and shortening of periosteum explants. In addition, remodeling under hypothetical conditions is explored to demonstrate how collagen might adapt to small differences in constraints. Typical aspects of all essentially different experimental conditions are captured quantitatively or qualitatively. Differences between predictions and experiments as well as new insights that emerge from the present simulations are discussed. This model is anticipated to evolve into a mechanistic description of collagen adaptation, which may assist in developing load-regimes for functional tissue engineered constructs, or may be employed to improve our understanding of the mechanisms behind physiological and pathological collagen remodeling. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physiological and psychological stress limits for astronautics Observations during the Skylab I-III missions

NASA Technical Reports Server (NTRS)

Burchard, E. C.

1975-01-01

The physiological and psychological factors of manned space flight had a particular significance in the Skylab missions during which astronauts were subjected to a life in a space environment for longer periods of time than on previous space missions. The Skylab missions demonstrated again the great adaptability of human physiology to the environment of man. The results of Skylab have indicated also approaches for enhancing the capability of man to tolerate the physiological and psychological stresses of space flight.

Studies of adaptive traits of Bali cattle in Buleleng district, Bali and Barru district, South Sulawesi

NASA Astrophysics Data System (ADS)

Aritonang, S. B.; Yuniati, R.; Abinawanto, Imron, M.; Bowolaksono, A.

2017-05-01

Bali cattle have high adaptability, so the distribution area is spread across Indonesia. These studies aimed to determine the effect of environmental factors on physiology performance of Bali cattle in Buleleng district and Barru district. Skin and rectal temperature and respiration rate within a minute were measured in cattle across 5-days. Ambient temperature, relative humidity, wind speed, and light intensity were measured as environmental factors. Our findings suggest that environmental factors between the two districts were different (p<0.05), but the temperature and wind speed were not. In Buleleng, the relative humidity was 82.6 ± 1 4.4% and light intensity was 123.03 ± 24.83 kW/m2, whereas in Barru the relative humidity was 75.4 ± 12.6% and light intensity was 200.96 ± 25.11 kW/m2. Although both regions had different environmental conditions, the respiration rate of cattle was different between the two districts (p<0.05). Cattle respiration rate in Buleleng was 26-34 BPM, whereas in Barru it was 22-28 BPM. Our results indicate that the changes in environmental conditions affect changes in the cattle physiology profile in each district. Thus, Bali cattle have adaptability towards a variety of environmental conditions.

Winning and losing: an evolutionary approach to mood disorders and their therapy.

PubMed

Sloman, Leon; Sturman, Edward D; Price, John S

2011-06-01

To advance a new evolutionary model that examines the effects of winning and losing on mood and physiological variables. Previous studies have focused on the involuntary defeat strategy in de-escalating conflict. Here, we propose that there also exists an involuntary winning strategy (IWS) that is triggered by success and characterized by euphoria and increased self-confidence. It motivates efforts to challenge, and promotes reconciliation. Previous studies are presented, including data on student athletes, demonstrating the impact of winning and losing on mood. Winning is consistently shown to be related to physiological changes such as increased testosterone and serotonin levels in primates. It reliably leads to mood changes that serve to motivate winners to continue their competitive efforts. When the IWS functions optimally, success leads to success in an adaptive cycle. Over time, the initial differences between the winners and losers of agonistic encounters become magnified in a process known as difference amplification. As a result of assortative mating, the children of people who have entered into an adaptive cycle will inherit traits from both parents that will, in turn, give them an increased competitive advantage. In this manner, difference amplification could have accelerated human evolution by natural selection. Vignettes of clinical interventions are also used to illustrate therapeutic strategies designed to disrupt maladaptive cycles and promote adaptive behaviour.

Models of Physiology/Cognition Relations: Their Prevalence in the Literature and Their Utility in Examining the Effect of Blood Pressure on Vocabulary and Memory for Designs.

ERIC Educational Resources Information Center

Sinnott, Jan D.; And Others

Interest in physiology/cognition relations is increasing, in step with the realization that the individual ages as a whole, adaptive, living system. If a physiological system declines, a person's cognitive abilities may be reduced, unless some compensatory mechanism operates. Understanding this set of relationships permits potential interventions.…

Annual Research Review: The Neurobiology and Physiology of Resilience and Adaptation across the Life Course

ERIC Educational Resources Information Center

Karatoreos, Ilia N.; McEwen, Bruce S.

2013-01-01

Background: Adaptation is key to survival. An organism must adapt to environmental challenges in order to be able to thrive in the environment in which they find themselves. Resilience can be thought of as a measure of the ability of an organism to adapt, and to withstand challenges to its stability. In higher animals, the brain is a key player in…

An adaptive Kalman filter technique for context-aware heart rate monitoring.

PubMed

Xu, Min; Goldfain, Albert; Dellostritto, Jim; Iyengar, Satish

2012-01-01

Traditional physiological monitoring systems convert a person's vital sign waveforms, such as heart rate, respiration rate and blood pressure, into meaningful information by comparing the instant reading with a preset threshold or a baseline without considering the contextual information of the person. It would be beneficial to incorporate the contextual data such as activity status of the person to the physiological data in order to obtain a more accurate representation of a person's physiological status. In this paper, we proposed an algorithm based on adaptive Kalman filter that describes the heart rate response with respect to different activity levels. It is towards our final goal of intelligent detection of any abnormality in the person's vital signs. Experimental results are provided to demonstrate the feasibility of the algorithm.

Effect of high temperature yoga exercise on improving physical and mental well-being of overweight middle-aged and young women

PubMed Central

Guo, Yan-Hua; Wang, Feng; Hu, Jian-Ping; Wang, Yi; Zhang, Li-Yan

2014-01-01

Objective: To explore the effect of high temperature yoga exercise on improving physical and psychological well-being of overweight middle-aged and young women. Design: 50 overweight middle-aged and young women from yoga clubs were selected. The indexes of their constitution, physiological functions, psychological adaptation were measured and compared before and after one year of uninterrupted high temperature yoga exercise. Results: The indexes of the subjects’ constitution and physiological functions were remarkably uplifted (P < 0.05); their psychological adaptation was improved as well. Conclusion: Aerobics represented by high temperature yoga can improve body shape, lower lipid, reduce weight, and exert an evident therapeutic effect on improving physiological functions and boosting psychological well-being. PMID:25664117

Investigations of respiratory control systems simulation

NASA Technical Reports Server (NTRS)

Gallagher, R. R.

1973-01-01

The Grodins' respiratory control model was investigated and it was determined that the following modifications were necessary before the model would be adaptable for current research efforts: (1) the controller equation must be modified to allow for integration of the respiratory system model with other physiological systems; (2) the system must be more closely correlated to the salient physiological functionings; (3) the respiratory frequency and the heart rate should be expanded to illustrate other physiological relationships and dependencies; and (4) the model should be adapted to particular individuals through a better defined set of initial parameter values in addition to relating these parameter values to the desired environmental conditions. Several of Milhorn's respiratory control models were also investigated in hopes of using some of their features as modifications for Grodins' model.

Physiological adaptations to weight loss and factors favouring weight regain

PubMed Central

Greenway, F L

2015-01-01

Obesity is a major global health problem and predisposes individuals to several comorbidities that can affect life expectancy. Interventions based on lifestyle modification (for example, improved diet and exercise) are integral components in the management of obesity. However, although weight loss can be achieved through dietary restriction and/or increased physical activity, over the long term many individuals regain weight. The aim of this article is to review the research into the processes and mechanisms that underpin weight regain after weight loss and comment on future strategies to address them. Maintenance of body weight is regulated by the interaction of a number of processes, encompassing homoeostatic, environmental and behavioural factors. In homoeostatic regulation, the hypothalamus has a central role in integrating signals regarding food intake, energy balance and body weight, while an ‘obesogenic' environment and behavioural patterns exert effects on the amount and type of food intake and physical activity. The roles of other environmental factors are also now being considered, including sleep debt and iatrogenic effects of medications, many of which warrant further investigation. Unfortunately, physiological adaptations to weight loss favour weight regain. These changes include perturbations in the levels of circulating appetite-related hormones and energy homoeostasis, in addition to alterations in nutrient metabolism and subjective appetite. To maintain weight loss, individuals must adhere to behaviours that counteract physiological adaptations and other factors favouring weight regain. It is difficult to overcome physiology with behaviour. Weight loss medications and surgery change the physiology of body weight regulation and are the best chance for long-term success. An increased understanding of the physiology of weight loss and regain will underpin the development of future strategies to support overweight and obese individuals in their efforts to achieve and maintain weight loss. PMID:25896063

Effects of steering demand on lane keeping behaviour, self-reports, and physiology. A simulator study.

PubMed

Dijksterhuis, Chris; Brookhuis, Karel A; De Waard, Dick

2011-05-01

In this study a driving simulator was used to determine changes in mental effort in response to manipulations of steering demand. Changes in mental effort were assessed by using subjective effort ratings, physiology, and the standard deviation of the lateral position. Steering demand was increased by exposure to narrow lane widths and high density oncoming traffic while speed was fixed in all conditions to prevent a compensatory reaction. Results indicated that both steering demand factors influence mental effort expenditure and using multiple measures contributes to effort assessment. Application of these outcomes for adaptive automation is envisaged. Copyright © 2010 Elsevier Ltd. All rights reserved.

Probiotics normalize the gut-brain-microbiota axis in immunodeficient mice

PubMed Central

Smith, Carli J.; Emge, Jacob R.; Berzins, Katrina; Lung, Lydia; Khamishon, Rebecca; Shah, Paarth; Rodrigues, David M.; Sousa, Andrew J.; Reardon, Colin; Sherman, Philip M.; Barrett, Kim E.

2014-01-01

The gut-brain-microbiota axis is increasingly recognized as an important regulator of intestinal physiology. Exposure to psychological stress causes activation of the hypothalamic-pituitary-adrenal (HPA) axis and causes altered intestinal barrier function, intestinal dysbiosis, and behavioral changes. The primary aim of this study was to determine whether the effects of psychological stress on intestinal physiology and behavior, including anxiety and memory, are mediated by the adaptive immune system. Furthermore, we wanted to determine whether treatment with probiotics would normalize these effects. Here we demonstrate that B and T cell-deficient Rag1−/− mice displayed altered baseline behaviors, including memory and anxiety, accompanied by an overactive HPA axis, increased intestinal secretory state, dysbiosis, and decreased hippocampal c-Fos expression. Both local (intestinal physiology and microbiota) and central (behavioral and hippocampal c-Fos) changes were normalized by pretreatment with probiotics, indicating an overall benefit on health conferred by changes in the microbiota, independent of lymphocytes. Taken together, these findings indicate a role for adaptive immune cells in maintaining normal intestinal and brain health in mice and show that probiotics can overcome this immune-mediated deficit in the gut-brain-microbiota axis. PMID:25190473

A Comparison of Student Academic Motivations across Three Course Disciplines

ERIC Educational Resources Information Center

Maurer, Trent W.; Allen, Deborah; Gatch, Delena Bell; Shankar, Padmini; Sturges, Diana

2013-01-01

Intrinsic and extrinsic motivations of undergraduate students enrolled in human anatomy and physiology, physics, and nutrition courses were explored with course discipline-specific adapted versions of the Academic Motivation Scale. Information on students' study habits and efforts, and final course grades were also collected. Results revealed the…

What's So Bad about Being Wet All Over: Investigating Leaf Surface Wetness.

ERIC Educational Resources Information Center

Brewer, Carol A.

1996-01-01

Presents investigations of leaf surface wetness that provide ideal opportunities for students to explore the relationships between leaf form and function, to study surface conditions of leaves and plant physiology, and to make predictions about plant adaptation in different environments. Describes simple procedures for exploring questions related…

Early Adversity, Elevated Stress Physiology, Accelerated Sexual Maturation, and Poor Health in Females

ERIC Educational Resources Information Center

Belsky, Jay; Ruttle, Paula L.; Boyce, W. Thomas; Armstrong, Jeffrey M.; Essex, Marilyn J.

2015-01-01

Evolutionary-minded developmentalists studying predictive-adaptive-response processes linking childhood adversity with accelerated female reproductive development and health scientists investigating the developmental origins of health and disease (DOoHaD) may be tapping the same process, whereby longer-term health costs are traded off for…

Bioassay of body fluids, experiment M073. [biochemical changes caused by space flight conditions

NASA Technical Reports Server (NTRS)

Leach, C. S.; Rambaut, P. C.

1973-01-01

Body fluids were assayed in this experiment to demonstrate changes which might have occurred during the 56-day chamber study in fluid and electrolyte balance, in regulation of calcium metabolism, in overall physiological and emotional adaptation to the environment, and in regulation of metabolic processes.

Outdoor Education--The Past Is Prologue to the Future.

ERIC Educational Resources Information Center

Rillo, Thomas J.

Although educators and philosophers such as Johann Amos Comenius, Jean Jacques Rousseau, Pestalozzi, and Froebel stressed the study of nature, outdoor education really began with the first teaching-learning act which occurred outdoors. The human being, physiologically and psychologically adapted for outdoor existence, has only been indoors for…

The basic helix-loop-helix transcription factor family in the sacred lotus, Nelumbo nucifera

USDA-ARS?s Scientific Manuscript database

Nelumbo nucifera (Sacred Lotus) is a basal eudicot with exceptional physiological and metabolic properties including seed longevity, adaptations for an aquatic habit, and floral thermiogenesis. It also occupies a unique position in the phylogeny of land plants and can be a useful species for studies...

Introgression of Novel Traits from a Wild Wheat Relative Improves Drought Adaptation in Wheat1[W

PubMed Central

Placido, Dante F.; Campbell, Malachy T.; Folsom, Jing J.; Cui, Xinping; Kruger, Greg R.; Baenziger, P. Stephen; Walia, Harkamal

2013-01-01

Root architecture traits are an important component for improving water stress adaptation. However, selection for aboveground traits under favorable environments in modern cultivars may have led to an inadvertent loss of genes and novel alleles beneficial for adapting to environments with limited water. In this study, we elucidate the physiological and molecular consequences of introgressing an alien chromosome segment (7DL) from a wild wheat relative species (Agropyron elongatum) into cultivated wheat (Triticum aestivum). The wheat translocation line had improved water stress adaptation and higher root and shoot biomass compared with the control genotypes, which showed significant drops in root and shoot biomass during stress. Enhanced access to water due to higher root biomass enabled the translocation line to maintain more favorable gas-exchange and carbon assimilation levels relative to the wild-type wheat genotypes during water stress. Transcriptome analysis identified candidate genes associated with root development. Two of these candidate genes mapped to the site of translocation on chromosome 7DL based on single-feature polymorphism analysis. A brassinosteroid signaling pathway was predicted to be involved in the novel root responses observed in the A. elongatum translocation line, based on the coexpression-based gene network generated by seeding the network with the candidate genes. We present an effective and highly integrated approach that combines root phenotyping, whole-plant physiology, and functional genomics to discover novel root traits and the underlying genes from a wild related species to improve drought adaptation in cultivated wheat. PMID:23426195

A Simulated Heat Wave Has Diverse Effects on Immune Function and Oxidative Physiology in the Corn Snake (Pantherophis guttatus).

PubMed

Stahlschmidt, Z R; French, S S; Ahn, A; Webb, A; Butler, M W

Animals will continue to encounter increasingly warm environments, including more frequent and intense heat waves. Yet the physiological consequences of heat waves remain equivocal, potentially because of variation in adaptive plasticity (reversible acclimation) and/or aspects of experimental design. Thus, we measured a suite of physiological variables in the corn snake (Pantherophis guttatus) after exposure to field-parameterized, fluctuating temperature regimes (moderate temperature and heat wave treatments) to address two hypotheses: (1) a heat wave causes physiological stress, and (2) thermal performance of immune function exhibits adaptive plasticity in response to a heat wave. We found little support for our first hypothesis because a simulated heat wave had a negative effect on body mass, but it also reduced oxidative damage and did not affect peak performance of three immune metrics. Likewise, we found only partial support for our second hypothesis. After exposure to a simulated heat wave, P. guttatus exhibited greater performance breadth and reduced temperature specialization (the standardized difference between peak performance and performance breadth) for only one of three immune metrics and did so in a sex-dependent manner. Further, a simulated heat wave did not elicit greater performance of any immune metric at higher temperatures. Yet a heat wave likely reduced innate immune function in P. guttatus because each metric of innate immune performance in this species (as in most vertebrates) was lower at elevated temperatures. Together with previous research, our study indicates that a heat wave may have complex, modest, and even positive physiological effects in some taxa.

Acute Physiological Responses to Strongman Training Compared to Traditional Strength Training.

PubMed

Harris, Nigel K; Woulfe, Colm J; Wood, Matthew R; Dulson, Deborah K; Gluchowski, Ashley K; Keogh, Justin B

2016-05-01

Strongman training (ST) has become an increasingly popular modality, but data on physiological responses are limited. This study sought to determine physiological responses to an ST session compared to a traditional strength exercise training (RST) session. Ten healthy men (23.6 ± 27.5 years, 85.8 ± 10.3 kg) volunteered in a crossover design, where all participants performed an ST session, an RST session, and a resting session within 7 days apart. The ST consisted of sled drag, farmer's walk, 1 arm dumbbell clean and press, and tire flip at loads eliciting approximately 30 seconds of near maximal effort per set. The RST consisted of squat, deadlift, bench press, and power clean, progressing to 75% of 1 repetition maximum. Sessions were equated for approximate total set duration. Blood lactate and salivary testosterone were recorded immediately before and after training sessions. Heart rate, caloric expenditure, and substrate utilization were measured throughout the resting session, both training protocols and for 80 minutes after training sessions. Analyses were conducted to determine differences in physiological responses within and between protocols. No significant changes in testosterone occurred at any time point for either session. Lactate increased significantly immediately after both sessions. Heart rate, caloric expenditure, and substrate utilization were all elevated significantly during ST and RST. Heart rate and fat expenditure were significantly elevated compared to resting in both sessions' recovery periods; calorie and carbohydrate expenditures were not. Compared to RST, ST represents an equivalent physiological stimulus on key parameters indicative of potential training-induced adaptive responses. Such adaptations could conceivably include cardiovascular conditioning.

A Physiologically-based Model for Methylmercury Uptake and Accumulation in Female American Kestrels

EPA Science Inventory

A physiologically-based model was developed to describe the uptake, distribution, and elimination of methylmercury in female American Kestrels (Falco sparverius). The model was adapted from established models for methylmercury in rodents. Features unique to the model include meth...

Human Adaptation to Space: Space Physiology and Countermeasures

NASA Technical Reports Server (NTRS)

Fogarty, Jennifer

2009-01-01

This viewgraph presentation reviews human physiological responses to spaceflight, and the countermeasures taken to prevent adverse effects of manned space flight. The topics include: 1) Human Spaceflight Experience; 2) Human Response to Spaceflight; 3) ISS Expeditions 1-16; 4) Countermeasure; and 5) Biomedical Data;

Cardiovascular physiology - Effects of microgravity

NASA Technical Reports Server (NTRS)

Convertino, V.; Hoffler, G. W.

1992-01-01

Experiments during spaceflight and its groundbase analog, bedrest, provide consistent data which demonstrate that numerous changes in cardiovascular function occur as part of the physiological adaptation process to the microgravity environment. These include elevated heart rate and venous compliance, lowered blood volume, central venous pressure and stroke volume, and attenuated autonomic reflex functions. Although most of these adaptations are not functionally apparent during microgravity exposure, they manifest themselves during the return to the gravitational challenge of earth's terrestrial environment as orthostatic hypotension and instability, a condition which could compromise safety, health and productivity. Development and application of effective and efficient countermeasures such as saline "loading," intermittent venous pooling, pharmacological treatments, and exercise have become primary emphases of the space life sciences research effort with only limited success. Successful development of countermeasures will require knowledge of the physiological mechanisms underlying cardiovascular adaptation to microgravity which can be obtained only through controlled, parallel groundbased research to complement carefully designed flight experiments. Continued research will provide benefits for both space and clinical applications as well as enhance the basic understanding of cardiovascular homeostasis in humans.

Phosphorus physiological ecology and molecular mechanisms in marine phytoplankton.

PubMed

Lin, Senjie; Litaker, Richard Wayne; Sunda, William G

2016-02-01

Phosphorus (P) is an essential nutrient for marine phytoplankton and indeed all life forms. Current data show that P availability is growth-limiting in certain marine systems and can impact algal species composition. Available P occurs in marine waters as dissolved inorganic phosphate (primarily orthophosphate [Pi]) or as a myriad of dissolved organic phosphorus (DOP) compounds. Despite numerous studies on P physiology and ecology and increasing research on genomics in marine phytoplankton, there have been few attempts to synthesize information from these different disciplines. This paper is aimed to integrate the physiological and molecular information on the acquisition, utilization, and storage of P in marine phytoplankton and the strategies used by these organisms to acclimate and adapt to variations in P availability. Where applicable, we attempt to identify gaps in our current knowledge that warrant further research and examine possible metabolic pathways that might occur in phytoplankton from well-studied bacterial models. Physical and chemical limitations governing cellular P uptake are explored along with physiological and molecular mechanisms to adapt and acclimate to temporally and spatially varying P nutrient regimes. Topics covered include cellular Pi uptake and feedback regulation of uptake systems, enzymatic utilization of DOP, P acquisition by phagotrophy, P-limitation of phytoplankton growth in oceanic and coastal waters, and the role of P-limitation in regulating cell size and toxin levels in phytoplankton. Finally, we examine the role of P and other nutrients in the transition of phytoplankton communities from early succession species (diatoms) to late succession ones (e.g., dinoflagellates and haptophytes). © 2015 Phycological Society of America.

Infant digestion physiology and the relevance of in vitro biochemical models to test infant formula lipid digestion.

PubMed

Poquet, Laure; Wooster, Tim J

2016-08-01

Lipids play an important role in the diet of preterm and term infants providing a key energy source and essential lipid components for development. While a lot is known about adult lipid digestion, our understanding of infant digestion physiology is still incomplete, the greatest gap being on the biochemistry of the small intestine, particularly the activity and relative importance of the various lipases active in the intestine. The literature has been reviewed to identify the characteristics of lipid digestion of preterm and term infants, but also to better understand the physiology of the infant gastrointestinal tract compared to adults that impacts the absorption of lipids. The main differences are a higher gastric pH, submicellar bile salt concentration, a far more important role of gastric lipases as well as differences at the level of the intestinal barrier. Importantly, the consequences of improper in vitro replication of gastric digestions conditions (pH and lipase specificity) are demonstrated using examples from the most recent of studies. It is true that some animal models could be adapted to study infant lipid digestion physiology, however the ethical relevance of such models is questionable, hence the development of accurate in vitro models is a must. In vitro models that combine up to date knowledge of digestion biochemistry with intestinal cells in culture are the best choice to replicate digestion and absorption in infant population, this would allow the adaptation of infant formula for a better digestion and absorption of dietary lipids by preterm and term infants. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Control of the annual cycle in birds: endocrine constraints and plasticity in response to ecological variability.

PubMed

Dawson, Alistair

2008-05-12

This paper reviews information from ecological and physiological studies to assess how extrinsic factors can modulate intrinsic physiological processes. The annual cycle of birds is made up of a sequence of life-history stages: breeding, moult and migration. Each stage has evolved to occur at the optimum time and to last for the whole duration of time available. Some species have predictable breeding seasons, others are more flexible and some breed opportunistically in response to unpredictable food availability. Photoperiod is the principal environmental cue used to time each stage, allowing birds to adapt their physiology in advance of predictable environmental changes. Physiological (neuroendocrine and endocrine) plasticity allows non-photoperiodic cues to modulate timing to enable individuals to cope with, and benefit from, short-term environmental variability. Although the timing and duration of the period of full gonadal maturation is principally controlled by photoperiod, non-photoperiodic cues, such as temperature, rainfall or food availability, could potentially modulate the exact time of breeding either by fine-tuning the time of egg-laying within the period of full gonadal maturity or, more fundamentally, by modulating gonadal maturation and/or regression. The timing of gonadal regression affects the time of the start of moult, which in turn may affect the duration of the moult. There are many areas of uncertainty. Future integrated studies are required to assess the scope for flexibility in life-history strategies as this will have a critical bearing on whether birds can adapt sufficiently rapidly to anthropogenic environmental changes, in particular climate change.

A systems biology approach to studying Tai Chi, physiological complexity and healthy aging: design and rationale of a pragmatic randomized controlled trial.

PubMed

Wayne, Peter M; Manor, Brad; Novak, Vera; Costa, Madelena D; Hausdorff, Jeffrey M; Goldberger, Ary L; Ahn, Andrew C; Yeh, Gloria Y; Peng, C-K; Lough, Matthew; Davis, Roger B; Quilty, Mary T; Lipsitz, Lewis A

2013-01-01

Aging is typically associated with progressive multi-system impairment that leads to decreased physical and cognitive function and reduced adaptability to stress. Due to its capacity to characterize complex dynamics within and between physiological systems, the emerging field of complex systems biology and its array of quantitative tools show great promise for improving our understanding of aging, monitoring senescence, and providing biomarkers for evaluating novel interventions, including promising mind-body exercises, that treat age-related disease and promote healthy aging. An ongoing, two-arm randomized clinical trial is evaluating the potential of Tai Chi mind-body exercise to attenuate age-related loss of complexity. A total of 60 Tai Chi-naïve healthy older adults (aged 50-79) are being randomized to either six months of Tai Chi training (n=30), or to a waitlist control receiving unaltered usual medical care (n=30). Our primary outcomes are complexity-based measures of heart rate, standing postural sway and gait stride interval dynamics assessed at 3 and 6months. Multiscale entropy and detrended fluctuation analysis are used as entropy- and fractal-based measures of complexity, respectively. Secondary outcomes include measures of physical and psychological function and tests of physiological adaptability also assessed at 3 and 6months. Results of this study may lead to novel biomarkers that help us monitor and understand the physiological processes of aging and explore the potential benefits of Tai Chi and related mind-body exercises for healthy aging. Copyright © 2012 Elsevier Inc. All rights reserved.

Exercise detraining: Applicability to microgravity

NASA Technical Reports Server (NTRS)

Coyle, Edward F.

1994-01-01

Physical training exposes the various systems of the body to potent physiologic stimuli. These stimuli induce specific adaptations that enhance an individual's tolerance for the type of exercise encountered in training. The level of adaptation and the magnitude of improvement in exercise tolerance is proportional to the potency of the physical training stimuli. Likewise, our bodies are stimulated by gravity, which promotes adaptations of both the cardiovascular and skeletal muscles. Exposure to microgravity removes normal stimuli to these systems, and the body adapts to these reduced demands. In many respects the cessation of physical training in athletes and the transition from normal gravity to microgravity represent similar paradigms. Inherent to these situations is the concept of the reversibility of the adaptations induced by training or by exposure to normal gravity. The reversibility concept holds that when physical training is stopped (i.e., detraining) or reduced, or a person goes from normal gravity to microgravity, the bodily systems readjust in accordance with the diminished physiologic stimuli. The focus of this chapter is on the time course of loss of the adaptations to endurance training as well as on the possibility that certain adaptations persist, to some extent, when training is stopped. Because endurance exercise training generally improves cardiovascular function and promotes metabolic adaptations within the exercising skeletal musculature, the reversibility of these specific adaptations is considered. These observations have some applicability to the transition from normal to microgravity.

Adapting Rehabilitation Counseling for Older Persons.

ERIC Educational Resources Information Center

Finnerty-Fried, Pamela

1985-01-01

The adaptations that might be advisable for rehabilitation practitioners working with older persons are outlined. Physiological and psychological changes related to aging are described, and social changes involving loss are mentioned. Accommodations that may help in working with older clients are recommended. (Author)

ULTRAVIOLET PROTECTIVE COMPOUNDS AS A RESPONSE TO ULTRAVIOLET RADIATION EXPOSURE

EPA Science Inventory

Life on Earth has evolved adaptations to many environmental stresses over the epochs. One consistent stress has been exposure to ultraviolet radiation. In response to UVR organisms have adapted myriad responses; behavioral, morphological and physiological. Behaviorally, some orga...

Stress reactivity, condition, and foraging behavior in zebra finches: effects on boldness, exploration, and sociality.

PubMed

Crino, O L; Buchanan, Katherine L; Trompf, Larissa; Mainwaring, Mark C; Griffith, Simon C

2017-04-01

The arid and semi-arid zones of Australia are characterized by highly variable and unpredictable environmental conditions which affect resources for flora and fauna. Environments which are highly unpredictable in terms of both resource access and distribution are likely to select for a variety of adaptive behavioral strategies, intrinsically linked to the physiological control of behavior. How unpredictable resource distribution has affected the coevolution of behavioral strategies and physiology has rarely been quantified, particularly not in Australian birds. We used a captive population of wild-derived zebra finches to test the relationships between behavioral strategies relating to food access and physiological responses to stress and body condition. We found that individuals that were in poorer body condition and had higher peak corticosterone levels entered baited feeders earlier in the trapping sequence of birds within the colony. We also found that individuals in poorer body condition fed in smaller social groups. Our data show that the foraging decisions which individuals make represent not only a trade-off between food access and risk of exposure, but their underlying physiological response to stress. Our data also suggest fundamental links between social networks and physiological parameters, which largely remain untested. These data demonstrate the fundamental importance of physiological mechanisms in controlling adaptive behavioral strategies and the dynamic interplay between physiological control of behavior and life-history evolution. Copyright © 2016 Elsevier Inc. All rights reserved.

Human physiological adaptation to extended Space Flight and its implications for Space Station

NASA Technical Reports Server (NTRS)

Kutyna, F. A.; Shumate, W. H.

1985-01-01

Current work evaluating short-term space flight physiological data on the homeostatic changes due to weightlessness is presented as a means of anticipating Space Station long-term effects. An integrated systems analysis of current data shows a vestibulo-sensory adaptation within days; a loss of body mass, fluids, and electrolytes, stabilizing in a month; and a loss in red cell mass over a month. But bone demineralization which did not level off is seen as the biggest concern. Computer algorithms have been developed to simulate the human adaptation to weightlessness. So far these paradigms have been backed up by flight data and it is hoped that they will provide valuable information for future Space Station design. A series of explanatory schematics is attached.

The battle within: understanding the physiology of war-zone stress exposure.

PubMed

Bruner, Victoria E; Woll, Pamela

2011-01-01

Faced with pervasive loss, life threat, and moral conflict in the field of battle, the human body and brain adapt to extraordinary circumstances in extraordinary ways. These adaptations come at a high price, and many men and women returning from Iraq and Afghanistan are paying that price every day. For the clinician who seeks to help, an understanding of the physiology of war-zone stress and resilience is an essential foundation, both for recovery from post-traumatic stress disorder and other conditions, and for addressing the stigma and shame that keep many service members and veterans from seeking and accepting the help and support they need. This article explores ways in which the body and brain adapt to war-zone stress, resulting challenges, and implications for clinical services and ongoing recovery.

Mathematical modeling of fluid-electrolyte alterations during weightlessness

NASA Technical Reports Server (NTRS)

Leonard, J. I.

1984-01-01

Fluid electrolyte metabolism and renal endocrine control as it pertains to adaptation to weightlessness were studied. The mathematical models that have been particularly useful are discussed. However, the focus of the report is on the physiological meaning of the computer studies. A discussion of the major ground based analogs of weightlessness are included; for example, head down tilt, water immersion, and bed rest, and a comparison of findings. Several important zero g phenomena are described, including acute fluid volume regulation, blood volume regulation, circulatory changes, longer term fluid electrolyte adaptations, hormonal regulation, and body composition changes. Hypotheses are offered to explain the major findings in each area and these are integrated into a larger hypothesis of space flight adaptation. A conceptual foundation for fluid electrolyte metabolism, blood volume regulation, and cardiovascular regulation is reported.

Androgen Metabolism in Progression to Androgen-Independent Prostate Cancer

DTIC Science & Technology

2011-06-01

confirming that AKR1C3 was mediating the synthesis of physiologically significant levels of testosterone from androstenedione. Although not selective, the... physiologically significant levels of androgen synthesis and AR reactivation (Figure 6D). While our data indicate that CYP17A1 mRNA is not...the micromolar range [14]. The low affinity of these antagonists compared to physiological ligands, in conjunction with adaptations that appear

Effect of Hypohydration and Altitude Exposure on Aerobic Exercise Performance and Acute Mountain Sickness

DTIC Science & Technology

2010-09-01

code) 2010 Journal Article-Journal of Applied Physiology Effect of hypohydration and altitude exposure on aerobic exercise performance and acute...1563. Visit our website at http://www.the-aps.org/. Physiological Society, 9650 Rockville Pike, Bethesda MD 20814-3991. Copyright © 2010 by the American... Physiological Society. those papers emphasizing adaptive and integrative mechanisms. It is published 12 times a year (monthly) by the American

Evolutionary History Underlies Plant Physiological Responses to Global Change Since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Becklin, K. M.; Medeiros, J. S.; Sale, K. R.; Ward, J. K.

2014-12-01

Assessing family and species-level variation in physiological responses to global change across geologic time is critical for understanding factors that underlie changes in species distributions and community composition. Ancient plant specimens preserved within packrat middens are invaluable in this context since they allow for comparisons between co-occurring plant lineages. Here we used modern and ancient plant specimens preserved within packrat middens from the Snake Range, NV to investigate the physiological responses of a mixed montane conifer community to global change since the last glacial maximum. We used a conceptual model to infer relative changes in stomatal conductance and maximum photosynthetic capacity from measures of leaf carbon isotopes, stomatal characteristics, and leaf nitrogen content. Our results indicate that most of the sampled taxa decreased stomatal conductance and/or photosynthetic capacity from glacial to modern times. However, plant families differed in the timing and magnitude of these physiological responses. Additionally, leaf-level responses were more similar within plant families than within co-occurring species assemblages. This suggests that adaptation at the level of leaf physiology may not be the main determinant of shifts in community composition, and that plant evolutionary history may drive physiological adaptation to global change over recent geologic time.

[Dependence of the pharmacokinetics of captopril on the type of adaptation reactions in the organism].

PubMed

Udut, V V; Khazanov, V A; Gurto, R V; Borodulina, E V; Postnikova, Iu E

2007-01-01

The dependence of the pharmacokinetic profiles (PhP) of captopril in the phase of adaptation reactions in the organism has been studied within the framework of randomized, comparative, double cross research of bioeqivalency of captopril (Aspharma Co, Anzhero-Sudzhensk) and capoten (Bristol Myers Squibb Co.; official Russian producer, Akrikhin KhimFarmKombinat). It is established that the maximum bioaccessibility and high concentration of captopril in the blood plasma is determined on the background of physiologically optimum reactions of training and in the zone of quiet activation. These characteristics decrease during the reactions of general adaptation syndrome according to the type of increased activation and reactivation.

Are interpretations of ancient marine temperatures constrained by the presence of ancient marine organisms?

NASA Technical Reports Server (NTRS)

Valentine, J. W.

1985-01-01

The relationship between marine temperature and marine organisms is investigated. The adaptation of organisms to extreme temperatures is studied; it is observed that chemautotrophic and chemoheterotrophic prokaryotes adapt to 100 C, photoautotrophic prokaryotes to 73 C, and fungi to 60 C. The physiological and molecular factors related to thermal limits in organisms such as enzymes, lipids, or plasma membranes, are examined. Two types of thermal adaptations, resistance and capacity, are detected in organisms. Reasons for species distributions according to temperature barriers are proposed by Read (1967) and Bullock (1955) and are related to enzyme limits. The effects of an organism's composition on thermal stability is analyzed.

Human Adaptation Genetic Response Suites: Toward New Interventions and Countermeasures for Spaceflight

NASA Technical Reports Server (NTRS)

Sundaresan, A.; Pellis, N. R.

2005-01-01

Genetic response suites in human lymphocytes in response to microgravity are important to identify and further study in order to augment human physiological adaptation to novel environments. Emerging technologies, such as DNA micro array profiling, have the potential to identify novel genes that are involved in mediating adaptation to these environments. These genes may prove to be therapeutically valuable as new targets for countermeasures, or as predictive biomarkers of response to these new environments. Human lymphocytes cultured in lg and microgravity analog culture were analyzed for their differential gene expression response. Different groups of genes related to the immune response, cardiovascular system and stress response were then analyzed. Analysis of cells from multiple donors reveals a small shared set that are likely to be essential to adaptation. These three groups focus on human adaptation to new environments. The shared set contains genes related to T cell activation, immune response and stress response to analog microgravity.

A systems approach to the physiology of weightlessness

NASA Technical Reports Server (NTRS)

White, Ronald J.; Leonard, Joel I.; Rummel, John A.; Leach, Carolyn S.

1991-01-01

A general systems approach to conducting and analyzing research on the human adaptation to weightlessness is presented. The research is aimed at clarifying the role that each of the major components of the human system plays following the transition to and from space. The approach utilizes a variety of mathematical models in order to pose and test alternative hypotheses concerned with the adaptation process. Certain aspects of the problem of fluid and electrolyte shifts in weightlessnes are considered, and an integrated hypothesis based on numerical simulation studies and experimental data is presented.

Physiological aeroecology: Anatomical and physiological adaptations for flight

USDA-ARS?s Scientific Manuscript database

Flight has evolved independently in birds, bats, and insects and was present in the Mesozoic pterosaurians that have disappeared. Of the roughly 1 million living animal species, more than three-quarters are flying insects. Flying is an extremely successful way of locomotion. At first glance this see...

Natural selection on thermal performance in a novel thermal environment

PubMed Central

Logan, Michael L.; Cox, Robert M.; Calsbeek, Ryan

2014-01-01

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming. PMID:25225361

Polar Marine Microorganisms and Climate Change.

PubMed

Verde, C; Giordano, D; Bellas, C M; di Prisco, G; Anesio, A M

2016-01-01

The large diversity of marine microorganisms harboured by oceans plays an important role in planet sustainability by driving globally important biogeochemical cycles; all primary and most secondary production in the oceans is performed by microorganisms. The largest part of the planet is covered by cold environments; consequently, cold-adapted microorganisms have crucial functional roles in globally important environmental processes and biogeochemical cycles cold-adapted extremophiles are a remarkable model to shed light on the molecular basis of survival at low temperature. The indigenous populations of Antarctic and Arctic microorganisms are endowed with genetic and physiological traits that allow them to live and effectively compete at the temperatures prevailing in polar regions. Some genes, e.g. glycosyltransferases and glycosylsynthetases involved in the architecture of the cell wall, may have been acquired/retained during evolution of polar strains or lost in tropical strains. This present work focusses on temperature and its role in shaping microbial adaptations; however, in assessing the impacts of climate changes on microbial diversity and biogeochemical cycles in polar oceans, it should not be forgotten that physiological studies need to include the interaction of temperature with other abiotic and biotic factors. © 2016 Elsevier Ltd All rights reserved.

Beyond the Paleolithic prescription: incorporating diversity and flexibility in the study of human diet evolution.

PubMed

Turner, Bethany L; Thompson, Amanda L

2013-08-01

Evolutionary paradigms of human health and nutrition center on the evolutionary discordance or "mismatch" model in which human bodies, reflecting adaptations established in the Paleolithic era, are ill-suited to modern industrialized diets, resulting in rapidly increasing rates of chronic metabolic disease. Though this model remains useful, its utility in explaining the evolution of human dietary tendencies is limited. The assumption that human diets are mismatched to the evolved biology of humans implies that the human diet is instinctual or genetically determined and rooted in the Paleolithic era. This review looks at current research indicating that human eating habits are learned primarily through behavioral, social, and physiological mechanisms that start in utero and extend throughout the life course. Adaptations that appear to be strongly genetic likely reflect Neolithic, rather than Paleolithic, adaptations and are significantly influenced by human niche-constructing behavior. Several examples are used to conclude that incorporating a broader understanding of both the evolved mechanisms by which humans learn and imprint eating habits and the reciprocal effects of those habits on physiology would provide useful tools for structuring more lasting nutrition interventions. © 2013 International Life Sciences Institute.

Natural selection on thermal performance in a novel thermal environment.

PubMed

Logan, Michael L; Cox, Robert M; Calsbeek, Ryan

2014-09-30

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation to changing conditions. Here, we mimic the effects of climate change by experimentally transplanting a population of Anolis sagrei lizards to a novel thermal environment. Transplanted lizards experienced warmer and more thermally variable conditions, which resulted in strong directional selection on thermal performance traits. These same traits were not under selection in a reference population studied in a less thermally stressful environment. Our results indicate that climate change can exert strong natural selection on tropical ectotherms, despite their ability to thermoregulate behaviorally. To the extent that thermal performance traits are heritable, populations may be capable of rapid adaptation to anthropogenic warming.

Global transcriptional, physiological and metabolite analyses of Desulfovibrio vulgaris Hildenborough responses to salt adaptation

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

He, Z.; Zhou, A.; Baidoo, E.

2009-12-01

The response of Desulfovibrio vulgaris Hildenborough to salt adaptation (long-term NaCl exposure) was examined by physiological, global transcriptional, and metabolite analyses. The growth of D. vulgaris was inhibited by high levels of NaCl, and the growth inhibition could be relieved by the addition of exogenous amino acids (e.g., glutamate, alanine, tryptophan) or yeast extract. Salt adaptation induced the expression of genes involved in amino acid biosynthesis and transport, electron transfer, hydrogen oxidation, and general stress responses (e.g., heat shock proteins, phage shock proteins, and oxidative stress response proteins). Genes involved in carbon metabolism, cell motility, and phage structures were repressed.more » Comparison of transcriptomic profiles of D. vulgaris responses to salt adaptation with those of salt shock (short-term NaCl exposure) showed some similarity as well as a significant difference. Metabolite assays showed that glutamate and alanine were accumulated under salt adaptation, suggesting that they may be used as osmoprotectants in D. vulgaris. A conceptual model is proposed to link the observed results to currently available knowledge for further understanding the mechanisms of D. vulgaris adaptation to elevated NaCl.« less

Non-climatic thermal adaptation: implications for species' responses to climate warming.

PubMed

Marshall, David J; McQuaid, Christopher D; Williams, Gray A

2010-10-23

There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models.

Functional genetic divergence in high CO2 adapted Emiliania huxleyi populations.

PubMed

Lohbeck, Kai T; Riebesell, Ulf; Collins, Sinéad; Reusch, Thorsten B H

2013-07-01

Predicting the impacts of environmental change on marine organisms, food webs, and biogeochemical cycles presently relies almost exclusively on short-term physiological studies, while the possibility of adaptive evolution is often ignored. Here, we assess adaptive evolution in the coccolithophore Emiliania huxleyi, a well-established model species in biological oceanography, in response to ocean acidification. We previously demonstrated that this globally important marine phytoplankton species adapts within 500 generations to elevated CO2 . After 750 and 1000 generations, no further fitness increase occurred, and we observed phenotypic convergence between replicate populations. We then exposed adapted populations to two novel environments to investigate whether or not the underlying basis for high CO2 -adaptation involves functional genetic divergence, assuming that different novel mutations become apparent via divergent pleiotropic effects. The novel environment "high light" did not reveal such genetic divergence whereas growth in a low-salinity environment revealed strong pleiotropic effects in high CO2 adapted populations, indicating divergent genetic bases for adaptation to high CO2 . This suggests that pleiotropy plays an important role in adaptation of natural E. huxleyi populations to ocean acidification. Our study highlights the potential mutual benefits for oceanography and evolutionary biology of using ecologically important marine phytoplankton for microbial evolution experiments. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

Psychological and physiological responses during an exam and their relation to personality characteristics.

PubMed

Spangler, G

1997-08-01

The aim of the study was to compare emotional and physiological responses to real and control examinations and to assess their relation to personality characteristics. Emotional responses were assessed by state anxiety and perceived stress. The assessment of physiological responses included the activity of the cardiac system (heart periods, vagal tone), the adrenocortical system (cortisol) and the immune system (immune globulin A, sIgA). Emotional and physiological responses of 23 students (12 males, 11 females) were assessed during an oral exam at the end of a basic course in psychology which was a prerequisite for the students' final exams. For the control condition physiological responses were assessed one week before the examination during a memory test. The findings of the study demonstrate different emotional and physiological response patterns to examinations as compared to the control condition. Heightened anxiety was observed only before the exam. Whereas within-situation physiological responses (higher heart periods, cortisol, and sIgA; lower vagal tone) were observed both under the exam and control condition, responses to exam condition indicated pre-exam anticipatory activation and post-exam restricted recovery responses. With regard to personality characteristics subjects with high ego-resiliency showed more flexible adaptation than subjects with low ego-resiliency both on the emotional level (anxiety down-regulation after exam) and on the physiological level (situation-specific responses, quick recovery). Subjects with high ego-control exhibited a lower physiological reactivity under both conditions, i.e. they seemed to maintain longer their control also on a physiological level independent of the type of situation.

Metabolic basis to Sherpa altitude adaptation

PubMed Central

Horscroft, James A.; Kotwica, Aleksandra O.; Laner, Verena; West, James A.; Hennis, Philip J.; Levett, Denny Z. H.; Howard, David J.; Fernandez, Bernadette O.; Burgess, Sarah L.; Ament, Zsuzsanna; Gilbert-Kawai, Edward T.; Vercueil, André; Landis, Blaine D.; Mythen, Monty G.; Branco, Cristina; Feelisch, Martin; Montgomery, Hugh E.; Griffin, Julian L.; Grocott, Michael P. W.; Gnaiger, Erich; Martin, Daniel S.; Murray, Andrew J.

2017-01-01

The Himalayan Sherpas, a human population of Tibetan descent, are highly adapted to life in the hypobaric hypoxia of high altitude. Mechanisms involving enhanced tissue oxygen delivery in comparison to Lowlander populations have been postulated to play a role in such adaptation. Whether differences in tissue oxygen utilization (i.e., metabolic adaptation) underpin this adaptation is not known, however. We sought to address this issue, applying parallel molecular, biochemical, physiological, and genetic approaches to the study of Sherpas and native Lowlanders, studied before and during exposure to hypobaric hypoxia on a gradual ascent to Mount Everest Base Camp (5,300 m). Compared with Lowlanders, Sherpas demonstrated a lower capacity for fatty acid oxidation in skeletal muscle biopsies, along with enhanced efficiency of oxygen utilization, improved muscle energetics, and protection against oxidative stress. This adaptation appeared to be related, in part, to a putatively advantageous allele for the peroxisome proliferator-activated receptor A (PPARA) gene, which was enriched in the Sherpas compared with the Lowlanders. Our findings suggest that metabolic adaptations underpin human evolution to life at high altitude, and could have an impact upon our understanding of human diseases in which hypoxia is a feature. PMID:28533386

Vibration exercise makes your muscles and bones stronger: fact or fiction?

PubMed

Cardinale, Marco; Rittweger, Jörn

2006-03-01

Vibration transmitted to the whole body or part of it has been extensively studied in relation to the risks to the health and safety of workers. These studies have highlighted the particular danger of lower-back morbidity and spinal trauma arising after prolonged exposure to vibration. However, short-term exposure to whole-body vibration (WBV) or the use of vibrating dumbbells can have beneficial effects on the musculoskeletal system. As a consequence of this encouraging work, many manufacturers have developed exercise devices characterized by vibrating plates transmitting vibration to the whole body and vibrating dumbbells. Preliminary results seem to recommend WBV exercise as a therapeutic alternative for preventing/reversing sarcopenia and possibly osteoporosis. However, there is a paucity of well designed studies in the elderly. In particular, there is a lack of understanding of the physiological mechanisms involved in the adaptive responses to vibration exposure, and of the most appropriate vibration parameters to be used in order to maximize gains and improve safety. The effectiveness of this novel exercise modality on musculoskeletal structures is examined in this review. The physiological mechanisms involved in the adaptive responses to vibration exercise are discussed and suggestions for future studies are made.

The predictive roles of neural oscillations in speech motor adaptability.

PubMed

Sengupta, Ranit; Nasir, Sazzad M

2016-06-01

The human speech system exhibits a remarkable flexibility by adapting to alterations in speaking environments. While it is believed that speech motor adaptation under altered sensory feedback involves rapid reorganization of speech motor networks, the mechanisms by which different brain regions communicate and coordinate their activity to mediate adaptation remain unknown, and explanations of outcome differences in adaption remain largely elusive. In this study, under the paradigm of altered auditory feedback with continuous EEG recordings, the differential roles of oscillatory neural processes in motor speech adaptability were investigated. The predictive capacities of different EEG frequency bands were assessed, and it was found that theta-, beta-, and gamma-band activities during speech planning and production contained significant and reliable information about motor speech adaptability. It was further observed that these bands do not work independently but interact with each other suggesting an underlying brain network operating across hierarchically organized frequency bands to support motor speech adaptation. These results provide novel insights into both learning and disorders of speech using time frequency analysis of neural oscillations. Copyright © 2016 the American Physiological Society.

The missing link in parasite manipulation of host behaviour.

PubMed

Herbison, Ryan; Lagrue, Clement; Poulin, Robert

2018-04-03

The observation that certain species of parasite my adaptively manipulate its host behaviour is a fascinating phenomenon. As a result, the recently established field of 'host manipulation' has seen rapid expansion over the past few decades with public and scientific interest steadily increasing. However, progress appears to falter when researchers ask how parasites manipulate behaviour, rather than why. A vast majority of the published literature investigating the mechanistic basis underlying behavioural manipulation fails to connect the establishment of the parasite with the reported physiological changes in its host. This has left researchers unable to empirically distinguish/identify adaptive physiological changes enforced by the parasites from pathological side effects of infection, resulting in scientists relying on narratives to explain results, rather than empirical evidence. By contrasting correlative mechanistic evidence for host manipulation against rare cases of causative evidence and drawing from the advanced understanding of physiological systems from other disciplines it is clear we are often skipping over a crucial step in host-manipulation: the production, potential storage, and release of molecules (manipulation factors) that must create the observed physiological changes in hosts if they are adaptive. Identifying these manipulation factors, via associating gene expression shifts in the parasite with behavioural changes in the host and following their effects will provide researchers with a bottom-up approach to unraveling the mechanisms of behavioural manipulation and by extension behaviour itself.

Growth and physiological plasticity among differentially adapted genotypes of a widespread C4 grass under altered precipitation

USDA-ARS?s Scientific Manuscript database

Background/Question/Methods Variation in precipitation expected with climate change may impact plant fitness and alter ecosystem dynamics by modifying species phenology, productivity, and physiology. Species responses to varied precipitation will depend in part on plastic responses of genotypes ad...

Conservation and modification of genetic and physiological toolkits underpinning diapause in bumble bee queens

USDA-ARS?s Scientific Manuscript database

Diapause is the key adaptation allowing insects to survive unfavourable conditions and inhabit an array of environments. Physiological changes during diapause are largely conserved across species and are hypothesized to be regulated by a conserved suite of genes (a ‘toolkit’). Furthermore, it is hyp...

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

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.

Human Behaviour in Long-Term Missions

NASA Technical Reports Server (NTRS)

1997-01-01

In this session, Session WP1, the discussion focuses on the following topics: Psychological Support for International Space Station Mission; Psycho-social Training for Man in Space; Study of the Physiological Adaptation of the Crew During A 135-Day Space Simulation; Interpersonal Relationships in Space Simulation, The Long-Term Bed Rest in Head-Down Tilt Position; Psychological Adaptation in Groups of Varying Sizes and Environments; Deviance Among Expeditioners, Defining the Off-Nominal Act in Space and Polar Field Analogs; Getting Effective Sleep in the Space-Station Environment; Human Sleep and Circadian Rhythms are Altered During Spaceflight; and Methodological Approach to Study of Cosmonauts Errors and Its Instrumental Support.

Physiological and Transcriptional Responses of Different Industrial Microbes at Near-Zero Specific Growth Rates.

PubMed

Ercan, Onur; Bisschops, Markus M M; Overkamp, Wout; Jørgensen, Thomas R; Ram, Arthur F; Smid, Eddy J; Pronk, Jack T; Kuipers, Oscar P; Daran-Lapujade, Pascale; Kleerebezem, Michiel

2015-09-01

The current knowledge of the physiology and gene expression of industrially relevant microorganisms is largely based on laboratory studies under conditions of rapid growth and high metabolic activity. However, in natural ecosystems and industrial processes, microbes frequently encounter severe calorie restriction. As a consequence, microbial growth rates in such settings can be extremely slow and even approach zero. Furthermore, uncoupling microbial growth from product formation, while cellular integrity and activity are maintained, offers perspectives that are economically highly interesting. Retentostat cultures have been employed to investigate microbial physiology at (near-)zero growth rates. This minireview compares information from recent physiological and gene expression studies on retentostat cultures of the industrially relevant microorganisms Lactobacillus plantarum, Lactococcus lactis, Bacillus subtilis, Saccharomyces cerevisiae, and Aspergillus niger. Shared responses of these organisms to (near-)zero growth rates include increased stress tolerance and a downregulation of genes involved in protein synthesis. Other adaptations, such as changes in morphology and (secondary) metabolite production, were species specific. This comparison underlines the industrial and scientific significance of further research on microbial (near-)zero growth physiology. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Evolutionary plant physiology: Charles Darwin's forgotten synthesis

NASA Astrophysics Data System (ADS)

Kutschera, Ulrich; Niklas, Karl J.

2009-11-01

Charles Darwin dedicated more than 20 years of his life to a variety of investigations on higher plants (angiosperms). It has been implicitly assumed that these studies in the fields of descriptive botany and experimental plant physiology were carried out to corroborate his principle of descent with modification. However, Darwin’s son Francis, who was a professional plant biologist, pointed out that the interests of his father were both of a physiological and an evolutionary nature. In this article, we describe Darwin’s work on the physiology of higher plants from a modern perspective, with reference to the following topics: circumnutations, tropisms and the endogenous oscillator model; the evolutionary patterns of auxin action; the root-brain hypothesis; phloem structure and photosynthesis research; endosymbioses and growth-promoting bacteria; photomorphogenesis and phenotypic plasticity; basal metabolic rate, the Pfeffer-Kleiber relationship and metabolic optimality theory with respect to adaptive evolution; and developmental constraints versus functional equivalence in relationship to directional natural selection. Based on a review of these various fields of inquiry, we deduce the existence of a Darwinian (evolutionary) approach to plant physiology and define this emerging scientific discipline as the experimental study and theoretical analysis of the functions of green, sessile organisms from a phylogenetic perspective.

Adaptive Mechanisms Underlying Microbial Resistance to Disinfectants

DTIC Science & Technology

2016-02-01

dilution]). A clinical surrogate, Escherichia coli , was used in these studies. E. coli cells were grown in the absence or presence of Lysol. The parent... Escherichia coli RTU strength Lysol Single nucleotide polymorphism (SNP...of Escheria coli with control sets of E.coli for physiological, biochemical, and genetic differences in an attempt to understand resistance

AUTOGENIC THERAPY IN TENSION HEADACHE

PubMed Central

Amruthraj, Brunda; Mishra, H.; Kumaraiah, V.

1987-01-01

SUMMARY Ten subjects diagnosed as Psychalgia were taken for study. A multiple baseline design was adapted and clients were subjected to 30 sessions of autogenic training. They were assessed using physiological (EMG and thermal change) and behavioural measures (Visual analogue scale and behavioural symptom checklist). Findings revealed autogenic therapy to be effective in reducing tension headache. PMID:21927245

COSMOS 2044 Mission: Overview

NASA Technical Reports Server (NTRS)

Grindeland, R. E.; Ballard, R. W.; Connol, J. P.; Vasques, M. F.

1992-01-01

The COSMOS 2044 spaceflight was the ninth Soviet-International joint mission dedicated to space biomedicine and the seventh in which the United States has participated. The unmanned Vostok vehicle carried 10 rats and two rhesus monkeys on its 14-day voyage. This spaceflight yielded an unprecedented bounty of data on physiological responses to the microgravity environment. The tissues studied and the numbers and types of studies performed by members of the international science community constituted a new record. Many of the results obtained by the approximately 80 American scientists who participated are reported in the series of COSMOS 2044 papers in this issue. Descriptions of the spaceflight and animal procedures are detailed elsewhere. The broad goals of the space biomedical program are threefold. The first is to characterize qualitatively and quantitatively the biological responses to the microgravity environment, be they adaptive or pathological. The second goal is to clarify the physiological-biochemical mechanisms mediating the responses to microgravity. The third goal of this program is to use the space environment as a tool to better understand adaptive and disease processes in terrestrial organisms.

The contribution of transcriptomic and proteomic analysis in elucidating stress adaptation responses of Listeria monocytogenes

USDA-ARS?s Scientific Manuscript database

The foodborne transmission of Listeria monocytogenes requires physiological adaptation to various conditions, including the cold, osmotic, heat, acid, alkaline, and oxidative stresses, associated with food hygiene, processing, and preservation measures. We review the current knowledge on the molecul...

Thermal adaptation of decomposer communities in warming soils

PubMed Central

Bradford, Mark A.

2013-01-01

Temperature regulates the rate of biogeochemical cycles. One way it does so is through control of microbial metabolism. Warming effects on metabolism change with time as physiology adjusts to the new temperature. I here propose that such thermal adaptation is observed in soil microbial respiration and growth, as the result of universal evolutionary trade-offs between the structure and function of both enzymes and membranes. I review the basis for these trade-offs and show that they, like substrate depletion, are plausible mechanisms explaining soil respiration responses to warming. I argue that controversies over whether soil microbes adapt to warming stem from disregarding the evolutionary physiology of cellular metabolism, and confusion arising from the term thermal acclimation to represent phenomena at the organism- and ecosystem-levels with different underlying mechanisms. Measurable physiological adjustments of the soil microbial biomass reflect shifts from colder- to warmer-adapted taxa. Hypothesized declines in the growth efficiency of soil microbial biomass under warming are controversial given limited data and a weak theoretical basis. I suggest that energy spilling (aka waste metabolism) is a more plausible mechanism for efficiency declines than the commonly invoked increase in maintenance-energy demands. Energy spilling has many fitness benefits for microbes and its response to climate warming is uncertain. Modeled responses of soil carbon to warming are sensitive to microbial growth efficiency, but declines in efficiency mitigate warming-induced carbon losses in microbial models and exacerbate them in conventional models. Both modeling structures assume that microbes regulate soil carbon turnover, highlighting the need for a third structure where microbes are not regulators. I conclude that microbial physiology must be considered if we are to have confidence in projected feedbacks between soil carbon stocks, atmospheric CO2, and climate change. PMID:24339821

Physiological adaptations to interval training and the role of exercise intensity

PubMed Central

MacInnis, Martin J.

2016-01-01

Abstract Interval exercise typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery. A common classification scheme subdivides this method into high‐intensity interval training (HIIT; ‘near maximal’ efforts) and sprint interval training (SIT; ‘supramaximal’ efforts). Both forms of interval training induce the classic physiological adaptations characteristic of moderate‐intensity continuous training (MICT) such as increased aerobic capacity (V˙O2 max ) and mitochondrial content. This brief review considers the role of exercise intensity in mediating physiological adaptations to training, with a focus on the capacity for aerobic energy metabolism. With respect to skeletal muscle adaptations, cellular stress and the resultant metabolic signals for mitochondrial biogenesis depend largely on exercise intensity, with limited work suggesting that increases in mitochondrial content are superior after HIIT compared to MICT, at least when matched‐work comparisons are made within the same individual. It is well established that SIT increases mitochondrial content to a similar extent to MICT despite a reduced exercise volume. At the whole‐body level, V˙O2 max is generally increased more by HIIT than MICT for a given training volume, whereas SIT and MICT similarly improve V˙O2 max despite differences in training volume. There is less evidence available regarding the role of exercise intensity in mediating changes in skeletal muscle capillary density, maximum stroke volume and cardiac output, and blood volume. Furthermore, the interactions between intensity and duration and frequency have not been thoroughly explored. While interval training is clearly a potent stimulus for physiological remodelling in humans, the integrative response to this type of exercise warrants further attention, especially in comparison to traditional endurance training. PMID:27748956

Physiologic Dysfunction Scores and Cognitive Function Test Performance in United States Adults

PubMed Central

Kobrosly, Roni W; Seplaki, Christopher L; Jones, Courtney M; van Wijngaarden, Edwin

2013-01-01

Objective To investigate the relationship between a measure of cumulative physiologic dysfunction and specific domains of cognitive function. Methods We examined a summary score measuring physiological dysfunction, a multisystem measure of the body’s ability to effectively adapt to physical and psychological demands, in relation to cognitive function deficits in a population of 4511 adults aged 20 to 59 who participated in the third National Health and Nutrition Examination Survey (1988–1994). Measures of cognitive function comprised three domains: working memory, visuomotor speed, and perceptual-motor speed. ‘Physiologic dysfunction’ scores summarizing measures of cardiovascular, immunologic, kidney, and liver function were explored. We used multiple linear regression models to estimate associations between cognitive function measures and physiological dysfunction scores, adjusting for socioeconomic factors, test conditions, and self-reported health factors. Results We noted a dose-response relationship between physiologic dysfunction and working memory (coefficient = 0.207, 95% CI = (0.066, 0.348), p < 0.0001) that persisted after adjustment for all covariates (p = 0.03). We did not observe any significant relationships between dysfunction scores and visuomotor (p = 0.37) or perceptual-motor ability (p = 0.33). Conclusions Our findings suggest that multisystem physiologic dysfunction is associated with working memory. Future longitudinal studies are needed to clarify the underlying mechanisms and explore the persistency of this association into later life. We suggest that such studies should incorporate physiologic data, neuroendocrine parameters, and a wide range of specific cognitive domains. PMID:22155941

The development of regulatory functions from birth to 5 years: insights from premature infants.

PubMed

Feldman, Ruth

2009-01-01

This study examined physiological, emotional, and attentional regulatory functions as predictors of self-regulation in 125 infants followed 7 times from birth to 5 years. Physiological regulation was assessed by neonatal vagal tone and sleep-wake cyclicity; emotion regulation by response to stress at 3, 6, and 12 months; and attention regulation by focused attention and delayed response in the 2nd year. Executive functions, behavior adaptation, and self-restraint were measured at 5 years. Regulatory functions showed stability across time, measures, and levels. Structural modeling demonstrated both mediated paths from physiological to self-regulation through emotional and attentional processes and direct continuity between vagal tone and each level of regulation. Results support the coherence of the regulation construct and are consistent with neurobiological models on self and consciousness.

Physiology can contribute to better understanding, management, and conservation of coral reef fishes

PubMed Central

Rummer, Jodie L.

2017-01-01

Abstract Coral reef fishes, like many other marine organisms, are affected by anthropogenic stressors such as fishing and pollution and, owing to climate change, are experiencing increasing water temperatures and ocean acidification. Against the backdrop of these various stressors, a mechanistic understanding of processes governing individual organismal performance is the first step for identifying drivers of coral reef fish population dynamics. In fact, physiological measurements can help to reveal potential cause-and-effect relationships and enable physiologists to advise conservation management by upscaling results from cellular and individual organismal levels to population levels. Here, we highlight studies that include physiological measurements of coral reef fishes and those that give advice for their conservation. A literature search using combined physiological, conservation and coral reef fish key words resulted in ~1900 studies, of which only 99 matched predefined requirements. We observed that, over the last 20 years, the combination of physiological and conservation aspects in studies on coral reef fishes has received increased attention. Most of the selected studies made their physiological observations at the whole organism level and used their findings to give conservation advice on population dynamics, habitat use or the potential effects of climate change. The precision of the recommendations differed greatly and, not surprisingly, was least concrete when studies examined the effects of projected climate change scenarios. Although more and more physiological studies on coral reef fishes include conservation aspects, there is still a lack of concrete advice for conservation managers, with only very few published examples of physiological findings leading to improved management practices. We conclude with a call to action to foster better knowledge exchange between natural scientists and conservation managers to translate physiological findings more effectively in order to obtain evidence-based and adaptive management strategies for the conservation of coral reef fishes. PMID:28852508

Dietary Antioxidants as Modifiers of Physiologic Adaptations to Exercise

PubMed Central

Mankowski, Robert T.; Anton, Stephen D.; Buford, Thomas W.; Leeuwenburgh, Christiaan

2015-01-01

Adaptive responses to exercise training (ET) are crucial in maintaining physiological homeostasis and health span. Exercise-induced aerobic bioenergetic reactions in mitochondria and cytosol increase production of reactive oxygen species (ROSs), where excess of ROS can be scavenged by enzymatic as well as non-enzymatic antioxidants to protect against deleterious oxidative stress. Free radicals, however, have recently been recognized as crucial signaling agents that promote adaptive mechanisms to ET, such as mitochondrial biogenesis, antioxidant (AO) enzyme activity defense system upregulation, insulin sensitivity, and glucose uptake in skeletal muscle. Commonly used non-enzymatic AO supplements, such as vitamins C and E, a-lipoic acid, and polyphenols, in combination with ET, have been proposed as ways to prevent exercise-induced oxidative stress and hence improve adaptation responses to endurance training. Preclinical and clinical studies to date have shown inconsistent results indicating either positive or negative effects of endurance training combined with different blends of AO supplements (mostly vitamins C and E and a-lipoic acid) on redox status, mitochondrial biogenesis pathways, and insulin sensitivity. Preclinical reports on ET combined with resveratrol, however, have shown consistent positive effects on exercise performance, mitochondrial biogenesis, and insulin sensitivity, with clinical trials reporting mixed effects. Relevant clinical studies have been few and have used inconsistent results and methodology (types of compounds, combinations, and supplementation time). The future studies would investigate the effects of specific antioxidants and other popular supplements, such as a-lipoic acid and resveratrol, on training effects in humans. Of particular importance are older adults who may be at higher risk of age-related increased oxidative stress, an impaired AO enzyme defense system, and comorbidities such as hypertension, insulin resistance, and diabetes. PMID:25606815

Aluminium tolerance and high phosphorus efficiency helps Stylosanthes better adapt to low-P acid soils.

PubMed

Du, Yu-Mei; Tian, Jiang; Liao, Hong; Bai, Chang-Jun; Yan, Xiao-Long; Liu, Guo-Dao

2009-06-01

Stylosanthes spp. (stylo) is one of the most important pasture legumes used in a wide range of agricultural systems on acid soils, where aluminium (Al) toxicity and phosphorus (P) deficiency are two major limiting factors for plant growth. However, physiological mechanisms of stylo adaptation to acid soils are not understood. Twelve stylo genotypes were surveyed under field conditions, followed by sand and nutrient solution culture experiments to investigate possible physiological mechanisms of stylo adaptation to low-P acid soils. Stylo genotypes varied substantially in growth and P uptake in low P conditions in the field. Three genotypes contrasting in P efficiency were selected for experiments in nutrient solution and sand culture to examine their Al tolerance and ability to utilize different P sources, including Ca-P, K-P, Al-P, Fe-P and phytate-P. Among the three tested genotypes, the P-efficient genotype 'TPRC2001-1' had higher Al tolerance than the P-inefficient genotype 'Fine-stem' as indicated by relative tap root length and haematoxylin staining. The three genotypes differed in their ability to utilize different P sources. The P-efficient genotype, 'TPRC2001-1', had superior ability to utilize phytate-P. The findings suggest that possible physiological mechanisms of stylo adaptation to low-P acid soils might involve superior ability of plant roots to tolerate Al toxicity and to utilize organic P and Al-P.

Adaptation and acclimatization to ocean acidification in marine ectotherms: an in situ transplant experiment with polychaetes at a shallow CO2 vent system

PubMed Central

Calosi, Piero; Rastrick, Samuel P. S.; Lombardi, Chiara; de Guzman, Heidi J.; Davidson, Laura; Jahnke, Marlene; Giangrande, Adriana; Hardege, Jörg D.; Schulze, Anja; Spicer, John I.; Gambi, Maria-Cristina

2013-01-01

Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO2. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2 vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO2. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO2, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO2 environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification. PMID:23980245

Adaptation and acclimatization to ocean acidification in marine ectotherms: an in situ transplant experiment with polychaetes at a shallow CO2 vent system.

PubMed

Calosi, Piero; Rastrick, Samuel P S; Lombardi, Chiara; de Guzman, Heidi J; Davidson, Laura; Jahnke, Marlene; Giangrande, Adriana; Hardege, Jörg D; Schulze, Anja; Spicer, John I; Gambi, Maria-Cristina

2013-01-01

Metabolic rate determines the physiological and life-history performances of ectotherms. Thus, the extent to which such rates are sensitive and plastic to environmental perturbation is central to an organism's ability to function in a changing environment. Little is known of long-term metabolic plasticity and potential for metabolic adaptation in marine ectotherms exposed to elevated pCO2. Consequently, we carried out a series of in situ transplant experiments using a number of tolerant and sensitive polychaete species living around a natural CO2 vent system. Here, we show that a marine metazoan (i.e. Platynereis dumerilii) was able to adapt to chronic and elevated levels of pCO2. The vent population of P. dumerilii was physiologically and genetically different from nearby populations that experience low pCO2, as well as smaller in body size. By contrast, different populations of Amphiglena mediterranea showed marked physiological plasticity indicating that adaptation or acclimatization are both viable strategies for the successful colonization of elevated pCO2 environments. In addition, sensitive species showed either a reduced or increased metabolism when exposed acutely to elevated pCO2. Our findings may help explain, from a metabolic perspective, the occurrence of past mass extinction, as well as shed light on alternative pathways of resilience in species facing ongoing ocean acidification.

Gender differences in hypoxic acclimatization in cyclooxygenase-2-deficient mice.

PubMed

Xu, Kui; Sun, Xiaoyan; Benderro, Girriso F; Tsipis, Constantinos P; LaManna, Joseph C

2017-02-01

The aim of this study was to determine the effect of cyclooxygenase-2 (COX-2) gene deletion on the adaptive responses during prolonged moderate hypobaric hypoxia. Wild-type (WT) and COX-2 knockout (KO) mice of both genders (3 months old) were exposed to hypobaric hypoxia (~0.4 ATM) or normoxia for 21 days and brain capillary densities were determined. Hematocrit was measured at different time intervals; brain hypoxia-inducible factor -1 α (HIF-1 α ), angiopoietin 2 (Ang-2), brain erythropoietin (EPO), and kidney EPO were measured under normoxic and hypoxic conditions. There were no gender differences in hypoxic acclimatization in the WT mice and similar adaptive responses were observed in the female KO mice. However, the male KO mice exhibited progressive vulnerability to prolonged hypoxia. Compared to the WT and female KO mice, the male COX-2 KO mice had significantly lower survival rate and decreased erythropoietic and polycythemic responses, diminished cerebral angiogenesis, decreased brain accumulation of HIF-1 α , and attenuated upregulation of VEGF, EPO, and Ang-2 during hypoxia. Our data suggest that there are physiologically important gender differences in hypoxic acclimatization in COX-2-deficient mice. The COX-2 signaling pathway appears to be required for acclimatization in oxygen-limiting environments only in males, whereas female COX-2-deficient mice may be able to access COX-2-independent mechanisms to achieve hypoxic acclimatization. © 2017 Case Western Reserve University. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

[Roles of organic acid metabolism in plant adaptation to nutrient deficiency and aluminum toxicity stress].

PubMed

Wang, Jianfei; Shen, Qirong

2006-11-01

Organic acids not only act as the intermediates in carbon metabolism, but also exert key roles in the plant adaptation to nutrient deficiency and metal stress and in the plant-microbe interactions at root-soil interface. From the viewpoint of plant nutrition, this paper reviewed the research progress on the formation and physiology of organic acids in plant, and their functions in nitrogen metabolism, phosphorus and iron uptake, aluminum tolerance, and soil ecology. New findings in the membrane transport of organic acids and the biotechnological manipulation of organic acids in transgenic model were also discussed. This novel perspectives of organic acid metabolism and its potential manipulation might present a possibility to understand the fundamental aspects of plant physiology, and lead to the new strategies to obtain crop varieties better adapted to environmental and metal stress.

Analysis of Gene Expression and Physiological Responses in Three Mexican Maize Landraces under Drought Stress and Recovery Irrigation

PubMed Central

Hayano-Kanashiro, Corina; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis; Simpson, June

2009-01-01

Background Drought is one of the major constraints for plant productivity worldwide. Different mechanisms of drought-tolerance have been reported for several plant species including maize. However, the differences in global gene expression between drought-tolerant and susceptible genotypes and their relationship to physiological adaptations to drought are largely unknown. The study of the differences in global gene expression between tolerant and susceptible genotypes could provide important information to design more efficient breeding programs to produce maize varieties better adapted to water limiting conditions. Methodology/Principal Findings Changes in physiological responses and gene expression patterns were studied under drought stress and recovery in three Mexican maize landraces which included two drought tolerant (Cajete criollo and Michoacán 21) and one susceptible (85-2) genotypes. Photosynthesis, stomatal conductance, soil and leaf water potentials were monitored throughout the experiment and microarray analysis was carried out on transcripts obtained at 10 and 17 days following application of stress and after recovery irrigation. The two tolerant genotypes show more drastic changes in global gene expression which correlate with different physiological mechanisms of adaptation to drought. Differences in the kinetics and number of up- and down-regulated genes were observed between the tolerant and susceptible maize genotypes, as well as differences between the two tolerant genotypes. Interestingly, the most dramatic differences between the tolerant and susceptible genotypes were observed during recovery irrigation, suggesting that the tolerant genotypes activate mechanisms that allow more efficient recovery after a severe drought. Conclusions/Significance A correlation between levels of photosynthesis and transcription under stress was observed and differences in the number, type and expression levels of transcription factor families were also identified under drought and recovery between the three maize landraces. Gene expression analysis suggests that the drought tolerant landraces have a greater capacity to rapidly modulate more genes under drought and recovery in comparison to the susceptible landrace. Modulation of a greater number of differentially expressed genes of different TF gene families is an important characteristic of the tolerant genotypes. Finally, important differences were also noted between the tolerant landraces that underlie different mechanisms of achieving tolerance. PMID:19888455

Perturbation schedule does not alter retention of a locomotor adaptation across days.

PubMed

Hussain, Sara J; Morton, Susanne M

2014-06-15

Motor adaptation in response to gradual vs. abrupt perturbation schedules may involve different neural mechanisms, potentially leading to different levels of motor memory. However, no study has investigated whether perturbation schedules alter memory of a locomotor adaptation across days. We measured adaptation and retention (memory) of altered interlimb symmetry during walking in two groups of participants over 2 days. On day 1, participants adapted to either a single, large perturbation (abrupt schedule) or a series of small perturbations that increased in size over time (gradual schedule). Retention was examined on day 2. On day 1, initial swing time and foot placement symmetry error sizes differed between groups but overall adaptation magnitudes were similar. On day 2, participants in both groups showed similar retention, readaptation, and aftereffect sizes, although there were some trends for improved memory in the abrupt group. These results conflict with previous data but are consistent with newer studies reporting no behavioral differences following adaptation using abrupt vs. gradual schedules. Although memory levels were very similar between groups, we cannot rule out the possibility that the neural mechanisms underlying this memory storage differ. Overall, it appears that adaptation of locomotor patterns via abrupt and gradual perturbation schedules produces similar expression of locomotor memories across days. Copyright © 2014 the American Physiological Society.

Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes: A Longitudinal Study

PubMed Central

Cassel, Michael; Intziegianni, Konstantina; Risch, Lucie; Müller, Steffen; Engel, Tilman; Mayer, Frank

2017-01-01

Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports. PMID:29075203

Complexities of gene expression patterns in natural populations of an extremophile fish (Poecilia mexicana, Poeciliidae)

PubMed Central

Passow, Courtney N.; Brown, Anthony P.; Arias-Rodriguez, Lenin; Yee, Muh-Ching; Sockell, Alexandra; Schartl, Manfred; Warren, Wesley C.; Bustamante, Carlos; Kelley, Joanna L.; Tobler, Michael

2017-01-01

Variation in gene expression can provide insights into organismal responses to environmental stress and physiological mechanisms mediating adaptation to habitats with contrasting environmental conditions. We performed an RNA-sequencing experiment to quantify gene expression patterns in fish adapted to habitats with different combinations of environmental stressors, including the presence of toxic hydrogen sulphide (H2S) and the absence of light in caves. We specifically asked how gene expression varies among populations living in different habitats, whether population differences were consistent among organs, and whether there is evidence for shared expression responses in populations exposed to the same stressors. We analysed organ-specific transcriptome-wide data from four ecotypes of Poecilia mexicana (nonsulphidic surface, sulphidic surface, nonsulphidic cave and sulphidic cave). The majority of variation in gene expression was correlated with organ type, and the presence of specific environmental stressors elicited unique expression differences among organs. Shared patterns of gene expression between populations exposed to the same environmental stressors increased with levels of organismal organization (from transcript to gene to physiological pathway). In addition, shared patterns of gene expression were more common between populations from sulphidic than populations from cave habitats, potentially indicating that physiochemical stressors with clear biochemical consequences can constrain the diversity of adaptive solutions that mitigate their adverse effects. Overall, our analyses provided insights into transcriptional variation in a unique system, in which adaptation to H2S and darkness coincide. Functional annotations of differentially expressed genes provide a springboard for investigating physiological mechanisms putatively underlying adaptation to extreme environments. PMID:28598519

Cardiac considerations in the triathlete.

PubMed

Douglas, P S

1989-10-01

The cardiac adaptation to exercise training produces a variety of adaptations in cardiac size, shape, and function. To further define these changes and to investigate the effects of maximal conditioning, we studied ultraendurance triathletes training for the Hawaii Ironman Triathlon using echocardiography, Doppler ultrasound, and electrocardiography. In this population, the left ventricle (LV) was of normal size but had increased wall thickness and mass. Systolic function was normal and diastolic function was normal or supernormal (increased ratio of rapid to atrial LV filling velocities). The finding of a pattern of concentric hypertrophy was reinforced by a close relationship between submaximal exercise systolic blood pressure and LV mass (r = 0.88). Examination of valvular function by Doppler ultrasound revealed significantly increased prevalences of mitral and tricuspid regurgitation in athletes, with 91% of athletes (vs 38% of controls) having regurgitation detected in at least one cardiac valve. Analysis of athletes using standard electrocardiographic criteria for the detection of left ventricular hypertrophy showed that these criteria did not reliably detect increased mass. However, changes such as marked QRS prolongation and nonvoltage criteria for LV hypertrophy and RV hypertrophy may be useful in separating physiologic from pathologic hypertrophy. Our studies provide additional descriptions of cardiac changes produced by ultraendurance exercise training and suggest that the hemodynamic load imposed by exercise may be a contributing cause to physiologic hypertrophy. Much yet remains to be learned about the cardiac adaptation to exercise training.

Biomineralization changes with food supply confer juvenile scallops (Argopecten purpuratus) resistance to ocean acidification.

PubMed

Ramajo, Laura; Marbà, Núria; Prado, Luis; Peron, Sophie; Lardies, Marco A; Rodriguez-Navarro, Alejandro B; Vargas, Cristian A; Lagos, Nelson A; Duarte, Carlos M

2016-06-01

Future ocean acidification (OA) will affect physiological traits of marine species, with calcifying species being particularly vulnerable. As OA entails high energy demands, particularly during the rapid juvenile growth phase, food supply may play a key role in the response of marine organisms to OA. We experimentally evaluated the role of food supply in modulating physiological responses and biomineralization processes in juveniles of the Chilean scallop, Argopecten purpuratus, that were exposed to control (pH ~ 8.0) and low pH (pH ~ 7.6) conditions using three food supply treatments (high, intermediate, and low). We found that pH and food levels had additive effects on the physiological response of the juvenile scallops. Metabolic rates, shell growth, net calcification, and ingestion rates increased significantly at low pH conditions, independent of food. These physiological responses increased significantly in organisms exposed to intermediate and high levels of food supply. Hence, food supply seems to play a major role modulating organismal response by providing the energetic means to bolster the physiological response of OA stress. On the contrary, the relative expression of chitin synthase, a functional molecule for biomineralization, increased significantly in scallops exposed to low food supply and low pH, which resulted in a thicker periostracum enriched with chitin polysaccharides. Under reduced food and low pH conditions, the adaptive organismal response was to trade-off growth for the expression of biomineralization molecules and altering of the organic composition of shell periostracum, suggesting that the future performance of these calcifiers will depend on the trajectories of both OA and food supply. Thus, incorporating a suite of traits and multiple stressors in future studies of the adaptive organismal response may provide key insights on OA impacts on marine calcifiers. © 2015 John Wiley & Sons Ltd.

Shift Work in Nurses: Contribution of Phenotypes and Genotypes to Adaptation

PubMed Central

Gamble, Karen L.; Motsinger-Reif, Alison A.; Hida, Akiko; Borsetti, Hugo M.; Servick, Stein V.; Ciarleglio, Christopher M.; Robbins, Sam; Hicks, Jennifer; Carver, Krista; Hamilton, Nalo; Wells, Nancy; Summar, Marshall L.; McMahon, Douglas G.; Johnson, Carl Hirschie

2011-01-01

Background Daily cycles of sleep/wake, hormones, and physiological processes are often misaligned with behavioral patterns during shift work, leading to an increased risk of developing cardiovascular/metabolic/gastrointestinal disorders, some types of cancer, and mental disorders including depression and anxiety. It is unclear how sleep timing, chronotype, and circadian clock gene variation contribute to adaptation to shift work. Methods Newly defined sleep strategies, chronotype, and genotype for polymorphisms in circadian clock genes were assessed in 388 hospital day- and night-shift nurses. Results Night-shift nurses who used sleep deprivation as a means to switch to and from diurnal sleep on work days (∼25%) were the most poorly adapted to their work schedule. Chronotype also influenced efficacy of adaptation. In addition, polymorphisms in CLOCK, NPAS2, PER2, and PER3 were significantly associated with outcomes such as alcohol/caffeine consumption and sleepiness, as well as sleep phase, inertia and duration in both single- and multi-locus models. Many of these results were specific to shift type suggesting an interaction between genotype and environment (in this case, shift work). Conclusions Sleep strategy, chronotype, and genotype contribute to the adaptation of the circadian system to an environment that switches frequently and/or irregularly between different schedules of the light-dark cycle and social/workplace time. This study of shift work nurses illustrates how an environmental “stress” to the temporal organization of physiology and metabolism can have behavioral and health-related consequences. Because nurses are a key component of health care, these findings could have important implications for health-care policy. PMID:21533241

CHRONIC ALCOHOL NEUROADAPTATION AND STRESS CONTRIBUTE TO SUSCEPTIBILITY FOR ALCOHOL CRAVING AND RELAPSE

PubMed Central

BREESE, GEORGE R.; SINHA, RAJITA; HEILIG, MARKUS

2010-01-01

Alcoholism is a chronic relapsing disorder. Major characteristics observed in alcoholics during an initial period of alcohol abstinence are altered physiological functions and a negative emotional state. Evidence suggests that a persistent, cumulative adaptation involving a kindling/allostasis-like process occurs during the course of repeated chronic alcohol exposures that is critical for the negative symptoms observed during alcohol withdrawal. Basic studies have provided evidence for specific neurotransmitters within identified brain sites being responsible for the negative emotion induced by the persistent cumulative adaptation following intermittent-alcohol exposures. After an extended period of abstinence, the cumulative alcohol adaptation increases susceptibility to stress- and alcohol cue-induced negative symptoms and alcohol seeking, both of which can facilitate excessive ingestion of alcohol. In the alcoholic, stressful imagery and alcohol cues alter physiological responses, enhance negative emotion, and induce craving. Brain fMRI imaging following stress and alcohol cues has documented neural changes in specific brain regions of alcoholics not observed in social drinkers. Such altered activity in brain of abstinent alcoholics to stress and alcohol cues is consistent with a continuing ethanol adaptation being responsible. Therapies in alcoholics found to block responses to stress and alcohol cues would presumably be potential treatments by which susceptibility for continued alcohol abuse can be reduced. By continuing to define the neurobiological basis of the sustained alcohol adaptation critical for the increased susceptibility of alcoholics to stress and alcohol cues that facilitate craving, a new era is expected to evolve in which the high rate of relapse in alcoholism is minimized. 250 PMID:20951730

The Integrated Impact of Diet On Human Immune Response, the Gut Microbiota, and Nutritional Status During Adaptation to a Spaceflight Analog

NASA Technical Reports Server (NTRS)

Douglas, G. L.; Zwart, S. R.; Young, M.; Kloeris, V.; Crucian, B.; Smith, S. M.; Lorenzi, H.

2017-01-01

Spaceflight impacts human physiology, including well documented immune system dysregulation. Diet, immune function, and the microbiome are interlinked, but diet is the only one of these factors that we have the ability to easily, and significantly, alter on Earth or during flight. As we understand dietary impacts on physiology more thoroughly, we may then improve the spaceflight diet to improve crew health and potentially reduce flight-associated physiological alterations. It is expected that increasing the consumption of fruits and vegetables and bioactive compounds (e.g.,omega-3 fatty acids, lycopene, flavonoids) and therefore enhancing overall nutritional intake from the nominal shelf-stable, fully-processed space food system could serve as a countermeasure to improve human immunological profiles, the taxonomic profile of the gut microbiota, and nutritional status, especially where currently dysregulated during spaceflight. This interdisciplinary study will determine the effect of the current shelf-stable spaceflight diet compared to an "enhanced" shelf-stable spaceflight diet (25% more foods rich in omega-3 fatty acids, lycopene, flavonoids, fruits, and vegetables). The NASA Human Exploration Research Analog (HERA) 2017 missions, consisting of closed chamber confinement, realistic mission simulation, in a high-fidelity mock space vehicle, will serve as a platform to replicate mission stressors and the dysregulated physiology observed in astronauts. Biosampling of crew members will occur at selected intervals, with complete dietary tracking. Outcome measures will include immune markers (e.g., peripheral leukocyte distribution, inflammatory cytokine profiles, T cell function), the taxonomic and metatranscriptomic profile of the gut microbiome, and nutritional status biomarkers and metabolites. Data collection will also include complete dietary tracking. Statistical evaluations will determine physiological and biochemical shifts in relation to nutrient in take and study phase. Beneficial improvements will provide evidence of the impact of diet on crew health and adaptation to this spaceflight analog, and will aid in the design and development of more-efficient targeted dietary interventions.

Resilience to Meet the Challenge of Addiction

PubMed Central

Alim, Tanja N.; Lawson, William B.; Feder, Adriana; Iacoviello, Brian M.; Saxena, Shireen; Bailey, Christopher R.; Greene, Allison M.; Neumeister, Alexander

2012-01-01

Acute and chronic stress–related mechanisms play an important role in the development of addiction and its chronic, relapsing nature. Multisystem adaptations in brain, body, behavioral, and social function may contribute to a dysregulated physiological state that is maintained beyond the homeostatic range. In addition, chronic abuse of substances leads to an altered set point across multiple systems. Resilience can be defined as the absence of psychopathology despite exposure to high stress and reflects a person’s ability to cope successfully in the face of adversity, demonstrating adaptive psychological and physiological stress responses. The study of resilience can be approached by examining interindividual stress responsibility at multiple phenotypic levels, ranging from psychological differences in the way people cope with stress to differences in neurochemical or neural circuitry function. The ultimate goal of such research is the development of strategies and interventions to enhance resilience and coping in the face of stress and prevent the onset of addiction problems or relapse. PMID:23584116

Early life adversity potentiates the effects of later life stress on cumulative physiological dysregulation.

PubMed

Dich, Nadya; Hansen, Åse Marie; Avlund, Kirsten; Lund, Rikke; Mortensen, Erik Lykke; Bruunsgaard, Helle; Rod, Naja Hulvej

2015-01-01

Previous research indicates that early life adversity may heighten stress reactivity and impair mechanisms for adaptive coping, suggesting that experience of stress in early life may also potentiate adults' physiological vulnerability to stress in later life. The study tested this hypothesis by investigating whether the experience of stressful events and circumstances (SEC) in childhood or adolescence amplified the effect of adulthood SEC on physiological dysregulation (allostatic load, AL) in later midlife. Observational data were used in the present study. Physiological functioning was measured in later midlife (participants' age ranged from 49 to 63 years). Both childhood/adolescence and adulthood SEC were reported retrospectively on the same occasion. Participants were 5309 Danish men and women from Copenhagen Aging and Midlife Biobank (CAMB). SEC included socioeconomic and family factors. The AL index was based on nine cardiovascular, metabolic, and immune biomarkers. Experience of SEC in both early life and adulthood independently predicted higher AL. In men, experience of SEC in early life also potentiated the effect of SEC in adulthood on AL. The results provide further insight into the mechanisms behind the "biological embedding" of childhood stress.

Cellular and molecular aspects of plant adaptation to microgravity

NASA Astrophysics Data System (ADS)

Kordyum, Elizabeth; Kozeko, Liudmyla

2016-07-01

Elucidation of the range and mechanisms of the biological effects of microgravity is one of the urgent fundamental tasks of space and gravitational biology. The absence of forbidding on plant growth and development in orbital flight allows studying different aspects of plant adaptation to this factor that is directly connected with development of the technologies of bioregenerative life-support systems. Microgravity belongs to the environmental factors which cause adaptive reactions at the cellular and molecular levels in the range of physiological responses in the framework of genetically determined program of ontogenesis. It is known that cells of a multicellular organism not only take part in reactions of the organism but also carry out processes that maintain their integrity. In light of these principles, the problem of identification of biochemical, physiological and structural patterns that can have adaptive significance at the cellular and molecular levels in real and simulated microgravity is considered. It is pointed that plant cell responses in microgravity and under clinorotation vary according to growth phase, physiological state, and taxonomic position of the object. At the same time, the responses have, to some degree, a similar character reflecting the changes in the cell organelle functional load. The maintenance of the plasmalemma fluidity at the certain level, an activation of both the antioxidant system and expression of HSP genes, especially HSP70, under increasing reactive oxygen species, lipid peroxidation intensity and alteration in protein homeostasis, are a strategic paradigm of rapid (primary) cell adaptation to microgravity. In this sense, biological membranes, especially plasmalemma, and their properties and functions may be considered as the most sensitive indicators of the influence of gravity or altered gravity on a cell. The plasmalemma lipid bilayer is a border between the cell internal content and environment, so it is a mediator between them. Diversity and modification of the membrane lipid content stipulate its participation in the regulation of many important cell processes. Metabolism intensification, including energetic, lipid and carbohydrate metabolism, an increase in the organelle functional load, and changes in enzyme activity promote the long-term (secondary) adaptation. The dynamics of these processes demonstrated that the adaptation occurs on the principle of self-regulating systems. We consider these available data as manifestations of phenotypic plasticity that provides plant adaptation to the unfavorable influence of microgravity. The concept that system's stability is provided by the ability of its components to lability in certain limits is a paradigm of modern science. In biology, it is phenotypic plasticity, i.e. a genome competence to change its expression and form different phenotypes in response to environmental fluctuations. Phenotypic plasticity is supposed to be performed within the limits of physiological reaction norm on the basis of metabolic and hormonal regulation of gene expression. We also discuss a possible role of epigenetic heredity, different forms of which are widely spread among plants due to their ability to vegetative propagation and peculiarities of developmental biology, in phenotypic plasticity, as its manifestations begin to reveal at the transcription level. Attraction of the ideas about the epigenetic control of gene expression will open the new level in understanding of plant adaptation to microgravity. In consideration of the adaptive responses to microgravity, plants reach the generative phase of ontogenesis in space flight, i.e. they are flowering and fruiting. However, a delay in synthesis of storage nutrients and the lower level of its accumulation in seeds in microgravity, as well as the formation of seeds with anomalous embryos in some cases have been described. These data made it impossible to say about full adaptation of plants to microgravity, because normal seed production is the major goal of their adaptation to the new conditions. Therefore, future research at the basis of modern methodology of space and gravitational biology are required to evaluate reasonably the adaptive potential of plants for long-term space flight.

Space flight rehabilitation.

PubMed

Payne, Michael W C; Williams, David R; Trudel, Guy

2007-07-01

The weightless environment of space imposes specific physiologic adaptations on healthy astronauts. On return to Earth, these adaptations manifest as physical impairments that necessitate a period of rehabilitation. Physiologic changes result from unloading in microgravity and highly correlate with those seen in relatively immobile terrestrial patient populations such as spinal cord, geriatric, or deconditioned bed-rest patients. Major postflight impairments requiring rehabilitation intervention include orthostatic intolerance, bone demineralization, muscular atrophy, and neurovestibular symptoms. Space agencies are preparing for extended-duration missions, including colonization of the moon and interplanetary exploration of Mars. These longer-duration flights will result in more severe and more prolonged disability, potentially beyond the point of safe return to Earth. This paper will review and discuss existing space rehabilitation plans for major postflight impairments. Evidence-based rehabilitation interventions are imperative not only to facilitate return to Earth but also to extend the safe duration of exposure to a physiologically hostile microgravity environment.

SLS-1 flight experiments preliminary significant results

NASA Technical Reports Server (NTRS)

1992-01-01

Spacelab Life Sciences-1 (SLS-1) is the first of a series of dedicated life sciences Spacelab missions designed to investigate the mechanisms involved in the physiological adaptation to weightlessness and the subsequent readaptation to 1 gravity (1 G). Hypotheses generated from the physiological effects observed during earlier missions led to the formulation of several integrated experiments to determine the underlying mechanisms responsible for the observed phenomena. The 18 experiments selected for flight on SLS-1 investigated the cardiovascular, cardiopulmonary, regulatory physiology, musculoskeletal, and neuroscience disciplines in both human and rodent subjects. The SLS-1 preliminary results gave insight to the mechanisms involved in the adaptation to the microgravity environment and readaptation when returning to Earth. The experimental results will be used to promote health and safety for future long duration space flights and, as in the past, will be applied to many biomedical problems encountered here on Earth.

What Has Natural Variation Taught Us about Plant Development, Physiology, and Adaptation?

PubMed Central

Alonso-Blanco, Carlos; Aarts, Mark G.M.; Bentsink, Leonie; Keurentjes, Joost J.B.; Reymond, Matthieu; Vreugdenhil, Dick; Koornneef, Maarten

2009-01-01

Nearly 100 genes and functional polymorphisms underlying natural variation in plant development and physiology have been identified. In crop plants, these include genes involved in domestication traits, such as those related to plant architecture, fruit and seed structure and morphology, as well as yield and quality traits improved by subsequent crop breeding. In wild plants, comparable traits have been dissected mainly in Arabidopsis thaliana. In this review, we discuss the major contributions of the analysis of natural variation to our understanding of plant development and physiology, focusing in particular on the timing of germination and flowering, plant growth and morphology, primary metabolism, and mineral accumulation. Overall, functional polymorphisms appear in all types of genes and gene regions, and they may have multiple mutational causes. However, understanding this diversity in relation to adaptation and environmental variation is a challenge for which tools are now available. PMID:19574434

The Cardiovascular Physiology of Sports and Exercise.

PubMed

Opondo, Mildred A; Sarma, Satyam; Levine, Benjamin D

2015-07-01

Athletes represent the extremes of human performance. Many of their remarkable abilities stem from a cardiovascular system that has adapted to meet the metabolic needs of exercising muscle. A large and compliant heart is a hallmark feature of athletes who engage in highly aerobic events. Despite high fitness levels, athletes may present with symptoms that limit performance. Understanding and dissecting these limitations requires a strong background in sports science and the factors that determine sports capabilities. This article reviews the basic principles of exercise physiology, cardiovascular adaptations unique to the "athlete's heart," and the utility of exercise testing in athletes. Copyright © 2015 Elsevier Inc. All rights reserved.

Immune System Dysfunction in the Elderly.

PubMed

Fuentes, Eduardo; Fuentes, Manuel; Alarcón, Marcelo; Palomo, Iván

2017-01-01

Human aging is characterized by both physical and physiological frailty that profoundly affects the immune system. In this context aging is associated with declines in adaptive and innate immunity established as immunosenescence. Immunosenescence is a new concept that reflects the age-associated restructuring changes of innate and adaptive immune functions. Thus elderly individuals usually present chronic low-level inflammation, higher infection rates and chronic diseases. A study of alterations in the immune system during aging could provide a potentially useful biomarker for the evaluation of immune senescence treatment. The immune system is the result of the interplay between innate and adaptive immunity, yet the impact of aging on this function is unclear. In this article the function of the immune system during aging is explored.

Body mass, composition, and food intake in rabbits during altered acceleration fields

NASA Technical Reports Server (NTRS)

Katovich, M. J.; Smith, A. H.

1978-01-01

Mature male Polish rabbits were subjected to varying gravitational fields in an animal centrifuge in order to evaluate the effects of acceleration and deacceleration on body mass, body composition, and food intake. The acceleration field intensity was increased by 0.25-G increments to a maximum of 2.5 G at intervals which permitted physiological adaptation at each field. Control animals of the same age were maintained at earth gravity under identical conditions of constant-light environment at a room temperature of 23 + or - 5 C. It is shown that increasing the acceleration-field intensity leads to a decrease in body mass. The regulated nature of this decreased body mass is tested by the response to an additional three-day fasting of animals adapted physiologically to 2.5 G. Ad libitum food intake per kg body mass per day tends to increase in chronically accelerated animals above 1.75 G. Increase in water content in centrifuged animals after physiological adaptation to 2.5 G is the result of decreasing body fat. Body mass and food intake returned to the precentrifuged levels of control animals within six weeks after cessation of centrifugation.

The physiological diversity and similarity of ten Quercus species

Treesearch

Shi-Jean S. Sung; M.N. Angelov; R.R. Doong; W.R. Harms; Paul P. Kormanik; C.C. Black

1994-01-01

Based on anatomical, photosynthetic, and biochemical data, the range of physiological differences and similarities was defined for ten Quercus species. There were no correlations between species' site adaptability, leaf anatomy and photosynthetic rate (A). It is concluded from these data that each oak species must be treated individually when incorporated into...

Promises and challenges of eco-physiological genomics in the field: Tests of drought responses in switchgrass

USDA-ARS?s Scientific Manuscript database

Knowledge of the physiological and genetic basis of stress tolerance has proven to be critical to understanding adaptation in both agricultural and natural systems. However, many discoveries were initially made in controlled conditions or laboratories, not in the field. To test the comparability o...

Cardiovascular and other dynamic systems in long-term space flight

NASA Technical Reports Server (NTRS)

Tipton, David A.

1987-01-01

The paper examines the physiology of the cardiovascular system, and to a lesser extent the endocrine, renal, and hematopoietic systems. The paper highlights the aspects of these areas that are most pertinent to space manufacturing, i.e., working in space. Areas covered include the physiological costs of working in microgravity and partial gravity (e.g., the moon or Mars), countermeasures to potentially adverse physiological adaptations, and problems associated with return to earth after long periods of weightlessness.

Research advances in major cereal crops for adaptation to abiotic stresses

PubMed Central

Maiti, RK; Satya, Pratik

2014-01-01

With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers’ fields. PMID:25523172

Comparative transcriptomics with self-organizing map reveals cryptic photosynthetic differences between two accessions of North American Lake cress.

PubMed

Nakayama, Hokuto; Sakamoto, Tomoaki; Okegawa, Yuki; Kaminoyama, Kaori; Fujie, Manabu; Ichihashi, Yasunori; Kurata, Tetsuya; Motohashi, Ken; Al-Shehbaz, Ihsan; Sinha, Neelima; Kimura, Seisuke

2018-02-19

Because natural variation in wild species is likely the result of local adaptation, it provides a valuable resource for understanding plant-environmental interactions. Rorippa aquatica (Brassicaceae) is a semi-aquatic North American plant with morphological differences between several accessions, but little information available on any physiological differences. Here, we surveyed the transcriptomes of two R. aquatica accessions and identified cryptic physiological differences between them. We first reconstructed a Rorippa phylogeny to confirm relationships between the accessions. We performed large-scale RNA-seq and de novo assembly; the resulting 87,754 unigenes were then annotated via comparisons to different databases. Between-accession physiological variation was identified with transcriptomes from both accessions. Transcriptome data were analyzed with principal component analysis and self-organizing map. Results of analyses suggested that photosynthetic capability differs between the accessions. Indeed, physiological experiments revealed between-accession variation in electron transport rate and the redox state of the plastoquinone pool. These results indicated that one accession may have adapted to differences in temperature or length of the growing season.

Research advances in major cereal crops for adaptation to abiotic stresses.

PubMed

Maiti, R K; Satya, Pratik

2014-01-01

With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers' fields.

Relationship between metal levels in the vent mussel Bathymodiolus azoricus and local microhabitat chemical characteristics of Eiffel Tower (Lucky Strike)

NASA Astrophysics Data System (ADS)

Martins, Inês; Cosson, Richard P.; Riou, Virginie; Sarradin, Pierre-Marie; Sarrazin, Jozée; Santos, Ricardo S.; Colaço, Ana

2011-03-01

The turbulent mixing of hydrothermal hot fluid with cold seawater creates large chemical gradients at a small spatial scale that may induce variable physiological and biochemical adaptations within the vent fauna. The adaptation to such a variable environment by the vent mussel Bathymodiolus azoricus relies on a dual symbiosis hosted in the gills, and digestion of particulate organic matter. The surrounding environment not only provides the necessary energy sources and suspended organic particles for the vent mussel nutrition, but also potentially toxic compounds such as metals. Our main goal was to see if there is a relation between metal accumulation in mussel organs and the chemical characteristics of their close environment. Mussels were collected at six locations in a cold part of the Eiffel Tower fluid-seawater mixing zone, characterized by distinct chemical compositions. Metals (Cd, Cu, Fe and Zn) and metallothioneins were quantified in the gills and digestive gland. The physiological condition of the sampled mussels was also evaluated using tissues and gill indices. Our study indicates that the accumulation of metals in B. azoricus is related to their spatial distribution and linked to fine scale environmental conditions that influence the physiological status of the organism.

Proteomic analysis of physiological function response to hot summer in liver from lactating dairy cows.

PubMed

Wang, Qiangjun; Zhao, Xiaowei; Zhang, Zijun; Zhao, Huiling; Huang, Dongwei; Cheng, Guanglong; Yang, Yongxin

2017-04-01

Lactation performance of dairy cattle is susceptible to heat stress. The liver is one of the most crucial organs affected by high temperature in dairy cows. However, the physiological adaption by the liver to hot summer conditions has not been well elucidated in lactating dairy cows. In the present study, proteomic analysis of the liver in dairy cows in spring and hot summer was performed using a label-free method. In total, 127 differentially expressed proteins were identified; most of the upregulated proteins were involved in protein metabolic processes and responses to stimuli, whereas most of the downregulated proteins were related to oxidation-reduction. Pathway analysis indicated that 3 upregulated heat stress proteins (HSP90α, HSP90β, and endoplasmin) were enriched in the NOD-like receptor signaling pathway, whereas several downregulated NADH dehydrogenase proteins were involved in the oxidative phosphorylation pathway. The protein-protein interaction network indicated that several upregulated HSPs (HSP90α, HSP90β, and GRP78) were involved in more interactions than other proteins and were thus considered as central hub nodes. Our findings provide novel insights into the physiological adaption of liver function in lactating dairy cows to natural high temperature. Copyright © 2017. Published by Elsevier Ltd.

Nutritional adaptation to seasonal climatic change: a study for rain-fed farmers in northeast Thailand.

PubMed

Murayama, Nobuko

2005-01-01

Based on the author's study of anthropometry, energy expenditure and food consumption in four (pre-harvest, harvest, post-harvest and rainy) seasons among rain-fed rice growing farmers in Northeast Thailand, this article clarifies and discusses human adaptive (or maladaptive) strategies to seasonal climatic change. Total energy expenditure fluctuated markedly among the four seasons, but total energy intake did to a negligible extent. Change in body weight significantly differed between pre-harvest and post-harvest seasons, with a magnitude of 1.3 kg, or 2.3%, in males and 2.5 kg, or 4.3%, in females. Respiratory quotient (RQ) was the lowest in the post-harvest season when fat mass increased. These results demonstrated that physiological adaptation, through change in RQ in particular, to change in energy balance occurred in relatively short periods, and thus behavioral adaptation by means of changes in energy intake was observed not in specific seasons but in a year. The nutritional-ecological adaptive patterns of the rain-fed rice farmers were compared with those of various subsistence populations based on physical activity levels.

Process- and controller-adaptations determine the physiological effects of cold acclimation.

PubMed

Werner, Jürgen

2008-09-01

Experimental results on physiological effects of cold adaptation seem confusing and apparently incompatible with one another. This paper will explain that a substantial part of such a variety of results may be deduced from a common functional concept. A core/shell treatment ("model") of the thermoregulatory system is used with mean body temperature as the controlled variable. Adaptation, as a higher control level, is introduced into the system. Due to persistent stressors, either the (heat transfer) process or the controller properties (parameters) are adjusted (or both). It is convenient to call the one "process adaptation" and the other "controller adaptation". The most commonly demonstrated effect of autonomic cold acclimation is a change in the controller threshold. The analysis shows that this necessarily means a lowering of body temperature because of a lowered metabolic rate. This explains experimental results on both Europeans in the climatic chamber and Australian Aborigines in a natural environment. Exclusive autonomic process adaptation occurs in the form of a better insulation. The analysis explains why the post-adaptive steady-state can only be achieved, if the controller system reduces metabolism and why in spite of this the new state is inevitably characterized by a rise in body temperature. If both process and controller adaptations are simultaneously present, there may be not any change of body temperature at all, e.g., as demonstrated in animal experiments. Whether this kind of adaptation delivers a decrease, an increase or no change of mean body temperature, depends on the proportion of process and controller adaptation.

Unique life sciences research facilities at NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Mulenburg, G. M.; Vasques, M.; Caldwell, W. F.; Tucker, J.

1994-01-01

The Life Science Division at NASA's Ames Research Center has a suite of specialized facilities that enable scientists to study the effects of gravity on living systems. This paper describes some of these facilities and their use in research. Seven centrifuges, each with its own unique abilities, allow testing of a variety of parameters on test subjects ranging from single cells through hardware to humans. The Vestibular Research Facility allows the study of both centrifugation and linear acceleration on animals and humans. The Biocomputation Center uses computers for 3D reconstruction of physiological systems, and interactive research tools for virtual reality modeling. Psycophysiological, cardiovascular, exercise physiology, and biomechanical studies are conducted in the 12 bed Human Research Facility and samples are analyzed in the certified Central Clinical Laboratory and other laboratories at Ames. Human bedrest, water immersion and lower body negative pressure equipment are also available to study physiological changes associated with weightlessness. These and other weightlessness models are used in specialized laboratories for the study of basic physiological mechanisms, metabolism and cell biology. Visual-motor performance, perception, and adaptation are studied using ground-based models as well as short term weightlessness experiments (parabolic flights). The unique combination of Life Science research facilities, laboratories, and equipment at Ames Research Center are described in detail in relation to their research contributions.

Heritability of climate-relevant traits in a rainforest skink.

PubMed

Martins, Felipe; Kruuk, Loeske; Llewelyn, John; Moritz, Craig; Phillips, Ben

2018-05-22

There is justified concern about the impact of global warming on the persistence of tropical ectotherms. There is also growing evidence for strong selection on climate-relevant physiological traits. Understanding the evolutionary potential of populations is especially important for low dispersal organisms in isolated populations, because these populations have little choice but to adapt. Despite this, direct estimates of heritability and genetic correlations for physiological traits in ectotherms-which will determine their evolutionary responses to selection-are sparse, especially for reptiles. Here we examine the heritabilities and genetic correlations for a set of four morphological and six climate-relevant physiological traits in an isolated population of an Australian rainforest lizard, Lampropholis coggeri. These traits show considerable variation across populations in this species, suggesting local adaptation. From laboratory crosses, we estimated very low to moderate heritability of temperature-related physiological traits (h 2  < 0.31), but significant and higher heritability of desiccation resistance (h 2 ~0.42). These values contrasted with uniformly higher heritabilities (h 2  > 0.51) for morphological traits. At the phenotypic level, there were positive associations among the morphological traits and between thermal limits. Growth rate was positively correlated with thermal limits, but there was no indication that morphology and physiology were linked in any other way. We found some support for a specialist-generalist trade-off in the thermal performance curve, but otherwise there was no evidence for evolutionary constraints, suggesting broadly labile multivariate trait structure. Our results indicate little potential to respond to selection on thermal traits in this population and provide new insights into the capacity of tropical ectotherms to adapt in situ to rapid climate change.

Starvation stress during larval development reveals predictive adaptive response in adult worker honey bees (Apis mellifera)

USDA-ARS?s Scientific Manuscript database

A variety of organisms exhibit developmental plasticity that results in differences in adult morphology, physiology or behavior. This variation in the phenotype, called “Predictive Adaptive Response (PAR),” gives a selective advantage in an adult's environment if the adult experiences environments s...

Reduced oxygen utilization in septic shock: disorder or adaptation?

PubMed

Steiner, Alexandre A

2015-01-01

A fall in oxygen utilization during septic or endotoxic shock is thought to reflect circulatory hypoxia or mitochondrial dysfunction, but these pathology-oriented hypotheses do not explain all clinical observations. Here we discuss an alternative hypothesis of how oxygen utilization could fall as the result of a physiological thermometabolic adaptation.

[Some adaptations of Monodonta turbinata (born, 1780) (Gastropoda, Prosobranchia, Trochidae) to feeding and habitation in the littoral zone].

PubMed

Aliakrinskaia, I O

2010-01-01

The basic morphological, ethological, and physiological-biochemical adaptations of Monodonta turbinata to survival in the littoral zone were investigated in this work. Quantitative estimation of myoglobin content in radular tissues of mollusks inhabiting the Mediterranean Sea Basin has been carried out.

Spiders in Motion: Demonstrating Adaptation, Structure-Function Relationships, and Trade-Offs in Invertebrates

ERIC Educational Resources Information Center

Bowlin, Melissa S.; McLeer, Dorothy F.; Danielson-Francois, Anne M.

2014-01-01

Evolutionary history and structural considerations constrain all aspects of animal physiology. Constraints on invertebrate locomotion are especially straightforward for students to observe and understand. In this exercise, students use spiders to investigate the concepts of adaptation, structure-function relationships, and trade-offs. Students…

Long-range correlations and fractal dynamics in C. elegans: Changes with aging and stress

NASA Astrophysics Data System (ADS)

Alves, Luiz G. A.; Winter, Peter B.; Ferreira, Leonardo N.; Brielmann, Renée M.; Morimoto, Richard I.; Amaral, Luís A. N.

2017-08-01

Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

Mechanisms and functional implications of motoneuron adaptations to increased physical activity.

PubMed

MacDonell, Christopher; Gardiner, Phillip

2018-06-01

Motoneurons demonstrate adaptations in their physiological properties to alterations in chronic activity levels. The most consistent change that appears to result from endurance-type exercise training is the reduced excitatory current required to initiate and maintain rhythmic firing. While the precise mechanisms through which these neurons adapt to activity are currently unknown, evidence exists that adaptation may involve alterations in the expression of genes that code for membrane receptors which can influence the responses of neurons to transmitters during activation. The influence of these adaptations may also extend to the resting condition, where ambient levels of neuroactive substances may influence ion conductances at rest, and thus result in the activation or inhibition of specific ion conductances that underlie the measurements of increased excitability that have been reported for motoneurons in the anesthetised state. We have applied motoneuron excitability and muscle unit contractile changes with endurance training to a mathematical computerised model of motor unit recruitment (Heckman and Binder, 1991). The results from the modelling exercise demonstrate increased task efficiency at relative levels of effort during a submaximal contraction. The physiological impact that nerve and muscle adaptations have on the neuromuscular system during standardized tasks seem to fit with reported changes in motor unit behaviour in trained human subjects.

Evaluation of an Adaptive Game that Uses EEG Measures Validated during the Design Process as Inputs to a Biocybernetic Loop.

PubMed

Ewing, Kate C; Fairclough, Stephen H; Gilleade, Kiel

2016-01-01

Biocybernetic adaptation is a form of physiological computing whereby real-time data streaming from the brain and body is used by a negative control loop to adapt the user interface. This article describes the development of an adaptive game system that is designed to maximize player engagement by utilizing changes in real-time electroencephalography (EEG) to adjust the level of game demand. The research consists of four main stages: (1) the development of a conceptual framework upon which to model the interaction between person and system; (2) the validation of the psychophysiological inference underpinning the loop; (3) the construction of a working prototype; and (4) an evaluation of the adaptive game. Two studies are reported. The first demonstrates the sensitivity of EEG power in the (frontal) theta and (parietal) alpha bands to changing levels of game demand. These variables were then reformulated within the working biocybernetic control loop designed to maximize player engagement. The second study evaluated the performance of an adaptive game of Tetris with respect to system behavior and user experience. Important issues for the design and evaluation of closed-loop interfaces are discussed.

RESILIENCE TO DROUGHTS IN MAMMALS: A CONCEPTUAL FRAMEWORK FOR ESTIMATING VULNERABILITY OF A SINGLE SPECIES.

PubMed

Rymer, Tasmin L; Pillay, Neville; Schradin, Carsten

2016-06-01

ABSTRACT The frequency and severity of droughts in certain areas is increasing as a consequence of climate change. The associated environmental challenges, including high temperatures, low food, and water availability, have affected, and will affect, many populations. Our aims are to review the behavioral, physiological, and morphological adaptations of mammals to arid environments, and to aid research- ers and nature conservationists about which traits they should study to assess whether or not their study species will be able to cope with droughts. We provide a suite of traits that should be considered when making predictions about species resilience to drought. We define and differentiate between general adaptations, specialized adaptations, and exaptations, and argue that specialized adaptations are of little interest in establishing how nondesert specialists will cope with droughts. Attention should be placed on general adaptations of semidesert species and assess whether these exist as exaptations in nondesert species. We conclude that phenotypic flexibility is the most important general adaptation that may promote species resilience. Thus, to assess whether a species will be able to cope with increasing aridity, it is important to establish the degree offlexibility of traits identified in semidesert species that confer afitness advantage under drying conditions.

Evaluation of an Adaptive Game that Uses EEG Measures Validated during the Design Process as Inputs to a Biocybernetic Loop

PubMed Central

Ewing, Kate C.; Fairclough, Stephen H.; Gilleade, Kiel

2016-01-01

Biocybernetic adaptation is a form of physiological computing whereby real-time data streaming from the brain and body is used by a negative control loop to adapt the user interface. This article describes the development of an adaptive game system that is designed to maximize player engagement by utilizing changes in real-time electroencephalography (EEG) to adjust the level of game demand. The research consists of four main stages: (1) the development of a conceptual framework upon which to model the interaction between person and system; (2) the validation of the psychophysiological inference underpinning the loop; (3) the construction of a working prototype; and (4) an evaluation of the adaptive game. Two studies are reported. The first demonstrates the sensitivity of EEG power in the (frontal) theta and (parietal) alpha bands to changing levels of game demand. These variables were then reformulated within the working biocybernetic control loop designed to maximize player engagement. The second study evaluated the performance of an adaptive game of Tetris with respect to system behavior and user experience. Important issues for the design and evaluation of closed-loop interfaces are discussed. PMID:27242486

Induction, adaptation and recovery of biological responses: implications for environmental monitoring.

PubMed

Wu, Rudolf S S; Siu, William H L; Shin, Paul K S

2005-01-01

A wide range of biological responses have been used to identify exposure to contaminants, monitor spatial and temporal changes in contamination levels, provide early warning of environmental deterioration and indicate occurrences of adverse ecological consequences. To be useful in environmental monitoring, a biological response must reflect the environmental stress over time in a quantitative way. We here argue that the time required for initial induction, maximum induction, adaptation and recovery of these stress responses must first be fully understood and considered before they can be used in environmental monitoring, or else erroneous conclusions (both false-negative and false-positive) may be drawn when interpreting results. In this study, data on initial induction, maximum induction, adaptation and recovery of stress responses at various biological hierarchies (i.e., molecular, biochemical, physiological, behavioral, cytological, population and community responses) upon exposure to environmentally relevant levels of contaminants (i.e., metals, oil, polycyclic aromatic hydrocarbons (PAHs), organochlorines, organophosphates, endocrine disruptors) were extracted from 922 papers in the biomarker literature and analyzed. Statistical analyses showed that: (a) many stress responses may decline with time after induction (i.e., adaptation), even if the level of stress remains constant; (b) times for maximum induction and recovery of biochemical responses are positively related; (c) there is no evidence to support the general belief that time for induction of responses at a lower biological hierarchy (i.e., molecular responses and biochemical responses) is shorter than that at higher hierarchy (i.e., physiological, cytological and behavioral responses), although longer recovery time is found for population and community responses; (d) there are significant differences in times required for induction and adaptation of biological responses caused by different types of contaminants; (e) times required for initial and maximum induction of physiological responses in fish are significantly longer than those in crustaceans; and (f) there is a paucity of data on adaptation and recovery of responses, especially those at population and community levels. The above analyses highlight: (1) the limitations and possible erroneous conclusions in the present use of biomarkers in biomonitoring programs, (2) the importance of understanding the details of temporal changes of biological responses before employing them in environmental management, and (3) the suitability of using specific animal groups as bioindicator species.

A physiological adaptation to undernutrition.

PubMed

Balam, G; Gurri, F

1994-01-01

A total of 432 children under the age of 10 years were measured for height and weight, and the morbidity and mortality indices were studied in six counties of the maize region of the state of Yucatán, Mexico. Undernutrition, because of its relationship to morbidity and mortality, was considered an important selection factor operating between the ages of 6 and 24 months. It was also observed that short stature was an adaptive response to the first years of undernutrition, that allowed children to maintain an adequate body weight under conditions of nutritional stress during the first 10 years of life.

Mycelial growth, pathogenicity, aggressiveness and apothecial development of Sclerotinia sclerotiorum isolates from Brazil and the United States in contrasting temperature regimes

USDA-ARS?s Scientific Manuscript database

Fungi can adapt to environmental conditions and produce different physiological responses. The aim of this study was to verify the existence of Sclerotinia sclerotiorum temperature ecotypes in isolates from Brazil and the USA. Ten S. sclerotiorum isolates from tropical and subtropical regions of Bra...

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

Treesearch

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

2015-01-01

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...

Physiological and molecular analysis of selected Kenyan maize lines for aluminum tolerance

USDA-ARS?s Scientific Manuscript database

Aluminum (Al) toxicity is an important limitation to maize production in many tropical and sub-tropical acid soil areas. The aim of this study was to survey the variation in Al tolerance in a panel of maize lines adapted for Kenya and look for novel sources of Al tolerance. 112 Kenyan maize accessio...

Interrelations between hydraulic and mechanical stress adaptations in woody plants

PubMed Central

Ennos, A Roland; Fournier, Meriem

2008-01-01

The fields of plant water relations and plant biomechanics have traditionally been studied separately even though often the same tissues are responsible for water transport and mechanical support. There is now increasing evidence that hydraulic and mechanical adaptations may influence one another. We studied the changes in the hydraulic and mechanical properties of the wood along lateral roots of two species of buttressed trees. In these roots, the mechanical contstraints quantified by strain measurements are known to decrease distally. Further, we investigated the effect of mechanical loading on the vessel anatomy in these and four other species of tropical trees. We found that as the strain decreased, the wood became progressively less stiff and strong but the conductivity increased exponentially. This was reflected in that adaptations towards re-enforcing mechanically loaded areas resulted in xylem with fewer and smaller vessels. In addition a controlled growth experiment on three tree species showed that drought adaptation may results in plants with stronger and stiffer tissue. Our results indicate that hydraulic and mechanical stress adaptations may be interrelated, and so support recent studied suggesting that physiological responses are complex balances rather than pure optimisations. PMID:19704486

Global variation in thermal tolerances and vulnerability of endotherms to climate change

PubMed Central

Khaliq, Imran; Hof, Christian; Prinzinger, Roland; Böhning-Gaese, Katrin; Pfenninger, Markus

2014-01-01

The relationships among species' physiological capacities and the geographical variation of ambient climate are of key importance to understanding the distribution of life on the Earth. Furthermore, predictions of how species will respond to climate change will profit from the explicit consideration of their physiological tolerances. The climatic variability hypothesis, which predicts that climatic tolerances are broader in more variable climates, provides an analytical framework for studying these relationships between physiology and biogeography. However, direct empirical support for the hypothesis is mostly lacking for endotherms, and few studies have tried to integrate physiological data into assessments of species' climatic vulnerability at the global scale. Here, we test the climatic variability hypothesis for endotherms, with a comprehensive dataset on thermal tolerances derived from physiological experiments, and use these data to assess the vulnerability of species to projected climate change. We find the expected relationship between thermal tolerance and ambient climatic variability in birds, but not in mammals—a contrast possibly resulting from different adaptation strategies to ambient climate via behaviour, morphology or physiology. We show that currently most of the species are experiencing ambient temperatures well within their tolerance limits and that in the future many species may be able to tolerate projected temperature increases across significant proportions of their distributions. However, our findings also underline the high vulnerability of tropical regions to changes in temperature and other threats of anthropogenic global changes. Our study demonstrates that a better understanding of the interplay among species' physiology and the geography of climate change will advance assessments of species' vulnerability to climate change. PMID:25009066

The Efficacy of Psychophysiological Measures for Implementing Adaptive Technology

NASA Technical Reports Server (NTRS)

Scerbo, Mark W.; Freeman, Frederick G.; Mikulka, Peter J.; Parasuraman, Raja; DiNocero, Francesco; Prinzel, Lawrence J., III

2001-01-01

Adaptive automation refers to technology that can change its mode of operation dynamically. Further, both the technology and the operator can initiate changes in the level or mode of automation. The present paper reviews research on adaptive technology. It is divided into three primary sections. In the first section, issues surrounding the development and implementation of adaptive automation are presented. Because physiological-based measures show much promise for implementing adaptive automation, the second section is devoted to examining candidate indices. In the final section, those techniques that show the greatest promise for adaptive automation as well as issues that still need to be resolved are discussed.

Enrichment and Physiological Characterization of a Cold-Adapted Nitrite-Oxidizing Nitrotoga sp. from an Eelgrass Sediment

PubMed Central

Ishii, Kento; Fujitani, Hirotsugu; Soh, Kentaro; Nakagawa, Tatsunori; Takahashi, Reiji

2017-01-01

ABSTRACT Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and potentially has high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga spp. results in a poor understanding of their ecophysiological features. In this study, we successfully enriched the nonmarine cold-adapted Nitrotoga sp. strain AM1 from coastal sand in an eelgrass zone and investigated its physiological characteristics. Multistep-enrichment approaches led to an increase in the abundance of AM1 to approximately 80% of the total bacterial population. AM1 was the only detectable NOB in the bacterial community. The 16S rRNA gene sequence of AM1 was 99.6% identical to that of “Candidatus Nitrotoga arctica,” which was enriched from permafrost-affected soil. The highest nitrogen oxidation rate of AM1 was observed at 16°C. The half-saturation constant (Km) and the generation time were determined to be 25 μM NO2− and 54 h, respectively. The nitrite oxidation rate of AM1 was stimulated at concentrations of <30 mM NH4Cl but completely inhibited at 50 mM NH4Cl. AM1 can grow well under specific environmental conditions, such as low temperature and in the presence of a relatively high concentration of free ammonia. These results help improve our comprehension of the functional importance of Nitrotoga. IMPORTANCE Nitrite-oxidizing bacteria (NOB) are key players in the second step of nitrification, which is an important process of the nitrogen cycle. Recent studies have suggested that the organisms of the novel NOB genus Nitrotoga were widely distributed and played a functional role in natural and engineered ecosystems. However, only a few Nitrotoga enrichments have been obtained, and little is known about their ecology and physiology. In this study, we successfully enriched a Nitrotoga sp. from sand in a shallow coastal marine ecosystem and undertook a physiological characterization. The laboratory experiments showed that the Nitrotoga enrichment culture could adapt not only to low temperature but also to relatively high concentrations of free ammonia. The determination of as-yet-unknown unique characteristics of Nitrotoga contributes to the improvement of our insights into the microbiology of nitrification. PMID:28500038

Enrichment and Physiological Characterization of a Cold-Adapted Nitrite-Oxidizing Nitrotoga sp. from an Eelgrass Sediment.

PubMed

Ishii, Kento; Fujitani, Hirotsugu; Soh, Kentaro; Nakagawa, Tatsunori; Takahashi, Reiji; Tsuneda, Satoshi

2017-07-15

Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and potentially has high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga spp. results in a poor understanding of their ecophysiological features. In this study, we successfully enriched the nonmarine cold-adapted Nitrotoga sp. strain AM1 from coastal sand in an eelgrass zone and investigated its physiological characteristics. Multistep-enrichment approaches led to an increase in the abundance of AM1 to approximately 80% of the total bacterial population. AM1 was the only detectable NOB in the bacterial community. The 16S rRNA gene sequence of AM1 was 99.6% identical to that of " Candidatus Nitrotoga arctica," which was enriched from permafrost-affected soil. The highest nitrogen oxidation rate of AM1 was observed at 16°C. The half-saturation constant ( K m ) and the generation time were determined to be 25 μM NO 2 - and 54 h, respectively. The nitrite oxidation rate of AM1 was stimulated at concentrations of <30 mM NH 4 Cl but completely inhibited at 50 mM NH 4 Cl. AM1 can grow well under specific environmental conditions, such as low temperature and in the presence of a relatively high concentration of free ammonia. These results help improve our comprehension of the functional importance of Nitrotoga IMPORTANCE Nitrite-oxidizing bacteria (NOB) are key players in the second step of nitrification, which is an important process of the nitrogen cycle. Recent studies have suggested that the organisms of the novel NOB genus Nitrotoga were widely distributed and played a functional role in natural and engineered ecosystems. However, only a few Nitrotoga enrichments have been obtained, and little is known about their ecology and physiology. In this study, we successfully enriched a Nitrotoga sp. from sand in a shallow coastal marine ecosystem and undertook a physiological characterization. The laboratory experiments showed that the Nitrotoga enrichment culture could adapt not only to low temperature but also to relatively high concentrations of free ammonia. The determination of as-yet-unknown unique characteristics of Nitrotoga contributes to the improvement of our insights into the microbiology of nitrification. Copyright © 2017 American Society for Microbiology.

Identifying signatures of natural selection in Tibetan and Andean populations using dense genome scan data.

PubMed

Bigham, Abigail; Bauchet, Marc; Pinto, Dalila; Mao, Xianyun; Akey, Joshua M; Mei, Rui; Scherer, Stephen W; Julian, Colleen G; Wilson, Megan J; López Herráez, David; Brutsaert, Tom; Parra, Esteban J; Moore, Lorna G; Shriver, Mark D

2010-09-09

High-altitude hypoxia (reduced inspired oxygen tension due to decreased barometric pressure) exerts severe physiological stress on the human body. Two high-altitude regions where humans have lived for millennia are the Andean Altiplano and the Tibetan Plateau. Populations living in these regions exhibit unique circulatory, respiratory, and hematological adaptations to life at high altitude. Although these responses have been well characterized physiologically, their underlying genetic basis remains unknown. We performed a genome scan to identify genes showing evidence of adaptation to hypoxia. We looked across each chromosome to identify genomic regions with previously unknown function with respect to altitude phenotypes. In addition, groups of genes functioning in oxygen metabolism and sensing were examined to test the hypothesis that particular pathways have been involved in genetic adaptation to altitude. Applying four population genetic statistics commonly used for detecting signatures of natural selection, we identified selection-nominated candidate genes and gene regions in these two populations (Andeans and Tibetans) separately. The Tibetan and Andean patterns of genetic adaptation are largely distinct from one another, with both populations showing evidence of positive natural selection in different genes or gene regions. Interestingly, one gene previously known to be important in cellular oxygen sensing, EGLN1 (also known as PHD2), shows evidence of positive selection in both Tibetans and Andeans. However, the pattern of variation for this gene differs between the two populations. Our results indicate that several key HIF-regulatory and targeted genes are responsible for adaptation to high altitude in Andeans and Tibetans, and several different chromosomal regions are implicated in the putative response to selection. These data suggest a genetic role in high-altitude adaption and provide a basis for future genotype/phenotype association studies necessary to confirm the role of selection-nominated candidate genes and gene regions in adaptation to altitude.

Identifying Signatures of Natural Selection in Tibetan and Andean Populations Using Dense Genome Scan Data

PubMed Central

Bigham, Abigail; Bauchet, Marc; Pinto, Dalila; Mao, Xianyun; Akey, Joshua M.; Mei, Rui; Scherer, Stephen W.; Julian, Colleen G.; Wilson, Megan J.; López Herráez, David; Brutsaert, Tom; Parra, Esteban J.; Moore, Lorna G.; Shriver, Mark D.

2010-01-01

High-altitude hypoxia (reduced inspired oxygen tension due to decreased barometric pressure) exerts severe physiological stress on the human body. Two high-altitude regions where humans have lived for millennia are the Andean Altiplano and the Tibetan Plateau. Populations living in these regions exhibit unique circulatory, respiratory, and hematological adaptations to life at high altitude. Although these responses have been well characterized physiologically, their underlying genetic basis remains unknown. We performed a genome scan to identify genes showing evidence of adaptation to hypoxia. We looked across each chromosome to identify genomic regions with previously unknown function with respect to altitude phenotypes. In addition, groups of genes functioning in oxygen metabolism and sensing were examined to test the hypothesis that particular pathways have been involved in genetic adaptation to altitude. Applying four population genetic statistics commonly used for detecting signatures of natural selection, we identified selection-nominated candidate genes and gene regions in these two populations (Andeans and Tibetans) separately. The Tibetan and Andean patterns of genetic adaptation are largely distinct from one another, with both populations showing evidence of positive natural selection in different genes or gene regions. Interestingly, one gene previously known to be important in cellular oxygen sensing, EGLN1 (also known as PHD2), shows evidence of positive selection in both Tibetans and Andeans. However, the pattern of variation for this gene differs between the two populations. Our results indicate that several key HIF-regulatory and targeted genes are responsible for adaptation to high altitude in Andeans and Tibetans, and several different chromosomal regions are implicated in the putative response to selection. These data suggest a genetic role in high-altitude adaption and provide a basis for future genotype/phenotype association studies necessary to confirm the role of selection-nominated candidate genes and gene regions in adaptation to altitude. PMID:20838600

Physiological adaptation of the growth-restricted fetus.

PubMed

Maršál, Karel

2018-05-01

The growth-restricted fetus in utero is exposed to a hostile environment and suffers undernutrition and hypoxia. To cope with the stress, the fetus changes its physiological functions. These adaptive changes aid intrauterine survival; however, they can lead to permanent functional and structural changes that can contribute to the development of serious chronic diseases later in life. Epigenetic mechanisms are an important part of the pathophysiological processes behind this "developmental origin of adult diseases." The dominant cardiovascular adaptive change is the redistribution of blood flow in hypoxic fetuses, with preferential supply of blood to the fetal brain, myocardium, and adrenal glands. The proportion of blood from the umbilical vein to the ductus venosus and foramen ovale increases, which increases the cardiac output of the left heart ventricle. The increased perfusion of fetal brain can be followed with Doppler ultrasound as increased diastolic velocities and decreased pulsatility index in the middle cerebral artery. Copyright © 2018. Published by Elsevier Ltd.

Relationship between physical attributes and heat stress in dairy cattle from different genetic groups

NASA Astrophysics Data System (ADS)

Alfonzo, Evelyn Priscila München; Barbosa da Silva, Marcos Vinicius Gualberto; dos Santos Daltro, Darlene; Stumpf, Marcelo Tempel; Dalcin, Vanessa Calderaro; Kolling, Giovani; Fischer, Vivian; McManus, Concepta Margaret

2016-02-01

Dairy cattle raised under harsh conditions have to adapt and prevent heat stress. The aim of this study was to evaluate physical characteristics and their association with heat tolerance in different genetic groups of dairy cattle. Thickness of the skin and coat, length and number of hairs, body measurements, as well as physiological parameters and body temperatures by infrared thermography were determined in 19 Holstein and 19 Girolando (½ and ¾ Holstein) cows. The Holstein cattle were less tolerant to heat stress than Girolando (GH50 and GH75 Holstein), because of the difficulty in dissipating heat due to the larger body size, as well as thicker and longer hairs. The correlations between physical characteristics, physiological parameters, and thermographic measurements prove to be inconsistent among genetic groups and therefore are not predictive of heat tolerance, while the regressions of morphometric characteristics on physiological and thermographic measures were not significant. Thus, the physical characteristics were not good predictors of physiological indices and thermographic temperature and so should not be used.

Relationship between physical attributes and heat stress in dairy cattle from different genetic groups.

PubMed

Alfonzo, Evelyn Priscila München; Barbosa da Silva, Marcos Vinicius Gualberto; dos Santos Daltro, Darlene; Stumpf, Marcelo Tempel; Dalcin, Vanessa Calderaro; Kolling, Giovani; Fischer, Vivian; McManus, Concepta Margaret

2016-02-01

Dairy cattle raised under harsh conditions have to adapt and prevent heat stress. The aim of this study was to evaluate physical characteristics and their association with heat tolerance in different genetic groups of dairy cattle. Thickness of the skin and coat, length and number of hairs, body measurements, as well as physiological parameters and body temperatures by infrared thermography were determined in 19 Holstein and 19 Girolando (½ and ¾ Holstein) cows. The Holstein cattle were less tolerant to heat stress than Girolando (GH50 and GH75 Holstein), because of the difficulty in dissipating heat due to the larger body size, as well as thicker and longer hairs. The correlations between physical characteristics, physiological parameters, and thermographic measurements prove to be inconsistent among genetic groups and therefore are not predictive of heat tolerance, while the regressions of morphometric characteristics on physiological and thermographic measures were not significant. Thus, the physical characteristics were not good predictors of physiological indices and thermographic temperature and so should not be used.

Chronobiology --2017 Nobel Prize in Physiology or Medicine.

PubMed

Yuan, Li; Li, Yi-Rou; Xu, Xiao-Dong

2018-01-20

Chronobiology is a field of biology that examines the generation of biological rhythms in various creatures and in many parts of body, and their adaptive fitness to solar- and lunar-related periodic phenomena. The synchronization of internal circadian clocks with external timing signals confers accurate phase response and tissue homeostasis. Herein we state a series of studies on circadian rhythms and introduce the brief history of chronobiology. We also present a detailed timeline of the discoveries on molecular mechanisms controlling circadian rhythm in Drosophila, which was awarded the 2017 Nobel Prize in Physiology or Medicine. The latest findings and new perspectives are further summarized to indicate the significance of circadian research.

Integration of statistical and physiological analyses of adaptation of near-isogenic barley lines.

PubMed

Romagosa, I; Fox, P N; García Del Moral, L F; Ramos, J M; García Del Moral, B; Roca de Togores, F; Molina-Cano, J L

1993-08-01

Seven near-isogenic barley lines, differing for three independent mutant genes, were grown in 15 environments in Spain. Genotype x environment interaction (G x E) for grain yield was examined with the Additive Main Effects and Multiplicative interaction (AMMI) model. The results of this statistical analysis of multilocation yield-data were compared with a morpho-physiological characterization of the lines at two sites (Molina-Cano et al. 1990). The first two principal component axes from the AMMI analysis were strongly associated with the morpho-physiological characters. The independent but parallel discrimination among genotypes reflects genetic differences and highlights the power of the AMMI analysis as a tool to investigate G x E. Characters which appear to be positively associated with yield in the germplasm under study could be identified for some environments.

Sex-specific ecophysiological responses to environmental fluctuations of free-ranging Hermann's tortoises: implication for conservation.

PubMed

Sibeaux, Adélaïde; Michel, Catherine Louise; Bonnet, Xavier; Caron, Sébastien; Fournière, Kévin; Gagno, Stephane; Ballouard, Jean-Marie

2016-01-01

Physiological parameters provide indicators to evaluate how organisms respond to conservation actions. For example, individuals translocated during reinforcement programmes may not adapt to their novel host environment and may exhibit elevated chronic levels of stress hormones and/or decreasing body condition. Conversely, successful conservation actions should be associated with a lack of detrimental physiological perturbation. However, physiological references fluctuate over time and are influenced by various factors (e.g. sex, age, reproductive status). It is therefore necessary to determine the range of natural variations of the selected physiological metrics to establish useful baselines. This study focuses on endangered free-ranging Hermann's tortoises ( Testudo hermanni hermanni ), where conservation actions have been preconized to prevent extinction of French mainland populations. The influence of sex and of environmental factors (site, year and season) on eight physiological parameters (e.g. body condition, corticosterone concentrations) was assessed in 82 individuals from two populations living in different habitats. Daily displacements were monitored by radio-tracking. Most parameters varied between years and seasons and exhibited contrasting sex patterns but with no or limited effect of site. By combining behavioural and physiological traits, this study provides sex-specific seasonal baselines that can be used to monitor the health status of Hermann's tortoises facing environmental threats (e.g. habitat changes) or during conservation actions (e.g. translocation). These results might also assist in selection of the appropriate season for translocation.

Microbial mats and the early evolution of life

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1990-01-01

Microbial mats have descended from perhaps the oldest and most widespread biological communities known. Mats harbor microbes that are crucial for studies of bacterial phylogeny and physiology. They illustrate how several oxygen-sensitive biochemical processes have adapted to oxygen, and they show how life adapted to dry land long before the rise of plants. The search for the earliest grazing protists and metazoa in stromatolites is aided by observations of mats: in them, organic compounds characteristic of ancient photosynthetic protists can be identified. Recent mat studies suggest that the 13C/12C increase observed over geological time in stromatolitic organic matter was driven at least in part by a long-term decline in atmospheric carbon dioxide levels.

Wireless powering and data telemetry for biomedical implants.

PubMed

Young, Darrin J

2009-01-01

Wireless powering and data telemetry techniques for two biomedical implant studies based on (1) wireless in vivo EMG sensor for intelligent prosthetic control and (2) adaptively RF powered implantable bio-sensing microsystem for real-time genetically engineered mice monitoring are presented. Inductive-coupling-based RF powering and passive data telemetry is effective for wireless in vivo EMG sensing, where the internal and external RF coils are positioned with a small separation distance and fixed orientation. Adaptively controlled RF powering and active data transmission are critical for mobile implant application such as real-time physiological monitoring of untethered laboratory animals. Animal implant studies have been successfully completed to demonstrate the wireless and batteryless in vivo sensing capabilities.

Obesity: a disease or a biological adaptation? An update.

PubMed

Chaput, J-P; Doucet, E; Tremblay, A

2012-08-01

Obesity is characterized by the accumulation of excess body fat and can be conceptualized as the physical manifestation of chronic energy excess. An important challenge of today's world is that our so-called obesogenic environment is conducive to the consumption of energy and unfavourable to the expenditure of energy. The modern, computer-dependent, sleep-deprived, physically inactive humans live chronically stressed in a society of food abundance. From a physiological standpoint, the excess weight gain observed in prone individuals is perceived as a normal consequence to a changed environment rather than a pathological process. In other words, weight gain is a sign of our contemporary way of living or a 'collateral damage' in the physiological struggle against modernity. Additionally, substantial body fat loss can complicate appetite control, decrease energy expenditure to a greater extent than predicted, increase the proneness to hypoglycaemia and its related risk towards depressive symptoms, increase the plasma and tissue levels of persistent organic pollutants that promote hormone disruption and metabolic complications, all of which are adaptations that can increase the risk of weight regain. In contrast, body fat gain generally provides the opposite adaptations, emphasizing that obesity may realistically be perceived as an a priori biological adaptation for most individuals. Accordingly, prevention and treatment strategies for obesity should ideally target the main drivers or root causes of body fat gain in order to be able to improve the health of the population. © 2012 The Authors. obesity reviews © 2012 International Association for the Study of Obesity.

Real-time assessment of mental workload using psychophysiological measures and artificial neural networks.

PubMed

Wilson, Glenn F; Russell, Christopher A

The functional state of the human operator is critical to optimal system performance. Degraded states of operator functioning can lead to errors and overall suboptimal system performance. Accurate assessment of operator functional state is crucial to the successful implementation of an adaptive aiding system. One method of determining operators' functional state is by monitoring their physiology. In the present study, artificial neural networks using physiological signals were used to continuously monitor, in real time, the functional state of 7 participants while they performed the Multi-Attribute Task Battery with two levels of task difficulty. Six channels of brain electrical activity and eye, heart and respiration measures were evaluated on line. The accuracy of the classifier was determined to test its utility as an on-line measure of operator state. The mean classification accuracies were 85%, 82%, and 86% for the baseline, low task difficulty, and high task difficulty conditions, respectively. The high levels of accuracy suggest that these procedures can be used to provide accurate estimates of operator functional state that can be used to provide adaptive aiding. The relative contribution of each of the 43 psychophysiological features was also determined. Actual or potential applications of this research include test and evaluation and adaptive aiding implementation.

Determination of cellular strains by combined atomic force microscopy and finite element modeling.

PubMed Central

Charras, Guillaume T; Horton, Mike A

2002-01-01

Many organs adapt to their mechanical environment as a result of physiological change or disease. Cells are both the detectors and effectors of this process. Though many studies have been performed in vitro to investigate the mechanisms of detection and adaptation to mechanical strains, the cellular strains remain unknown and results from different stimulation techniques cannot be compared. By combining experimental determination of cell profiles and elasticities by atomic force microscopy with finite element modeling and computational fluid dynamics, we report the cellular strain distributions exerted by common whole-cell straining techniques and from micromanipulation techniques, hence enabling their comparison. Using data from our own analyses and experiments performed by others, we examine the threshold of activation for different signal transduction processes and the strain components that they may detect. We show that modulating cell elasticity, by increasing the F-actin content of the cytoskeleton, or cellular Poisson ratio are good strategies to resist fluid shear or hydrostatic pressure. We report that stray fluid flow in some substrate-stretch systems elicits significant cellular strains. In conclusion, this technique shows promise in furthering our understanding of the interplay among mechanical forces, strain detection, gene expression, and cellular adaptation in physiology and disease. PMID:12124270

Effects of heat and cold on health, with special reference to Finnish sauna bathing.

PubMed

Heinonen, Ilkka; Laukkanen, Jari A

2018-05-01

Environmental stress such as extremely warm or cold temperature is often considered a challenge to human health and body homeostasis. However, the human body can adapt relatively well to heat and cold environments, and recent studies have also elucidated that particularly heat stress might be even highly beneficial for human health. Consequently, the aim of the present brief review is first to discuss general cardiovascular and other responses to acute heat stress, followed by a review of beneficial effects of Finnish sauna bathing on general and cardiovascular health and mortality as well as dementia and Alzheimer's disease risk. Plausible mechanisms included are improved endothelial and microvascular function, reduced blood pressure and arterial stiffness, and possibly increased angiogenesis in humans, which are likely to mediate the health benefits of sauna bathing. In addition to heat exposure with physiological adaptations, cold stress-induced physiological responses and brown fat activation on health are also discussed. This is important to take into consideration, as sauna bathing is frequently associated with cooling periods in cold(er) environments, but their combination remains poorly investigated. We finally propose, therefore, that possible additive effects of heat- and cold-stress-induced adaptations and effects on health would be worthy of further investigation.

Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review.

PubMed

Burtscher, Martin; Gatterer, Hannes; Burtscher, Johannes; Mairbäurl, Heimo

2018-01-01

Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia.

Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review

PubMed Central

Burtscher, Martin; Gatterer, Hannes; Burtscher, Johannes; Mairbäurl, Heimo

2018-01-01

Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia. PMID:29867589

Influence of different seasons during late gestation on Holstein cows' colostrum and postnatal adaptive capability of their calves

NASA Astrophysics Data System (ADS)

Trifković, Julijana; Jovanović, Ljubomir; Đurić, Miloje; Stevanović-Đorđević, Snežana; Milanović, Svetlana; Lazarević, Miodrag; Sladojević, Željko; Kirovski, Danijela

2018-06-01

Season may affect calves' thermal comfort and behavior, but the data related to the overall influence of seasonal variations on dams' colostrum and postnatal adaptive capability of calves are limited. The aim of this study was to measure the effects of a 49-day-long low air temperature (LAT) season (5.20 ± 0.46 °C mean air temperature) and a 53-day-long high air temperature (HAT) season (27.40 ± 0.39 °C mean air temperature) on dams' colostrum quality and physiological, biochemical, hormonal, and oxidative stress parameters of their calves during the first 7 days of life. The dams' colostrum was sampled at 2, 14, and 26 h after calving, before feeding of their calves. Calves' blood samples were taken before the first colostrum intake and on days 1, 2, 3, and 7 of life. Calves' physiological parameters were measured on days 0 and 7. HAT season significantly reduced the quality of dams' colostrum. The ingestion of the low-quality colostrum, combined with the thermal discomfort during HAT season, probably provoked impaired physiological, biochemical, hormonal, and oxidative stress parameters in samples taken from the post-colostral calves. Additionally, intravenous glucose tolerance test was performed on day 7, which suggested an enhanced insulin response in HAT season calves. This study highlights the importance of adequate supporting strategies for the care of the late gestation cows and postnatal calves during the HAT season.

Extraversion and cardiovascular responses to recurrent social stress: Effect of stress intensity.

PubMed

Lü, Wei; Xing, Wanying; Hughes, Brian M; Wang, Zhenhong

2017-10-28

The present study sought to establish whether the effects of extraversion on cardiovascular responses to recurrent social stress are contingent on stress intensity. A 2×5×1 mixed-factorial experiment was conducted, with social stress intensity as a between-subject variable, study phase as a within-subject variable, extraversion as a continuous independent variable, and cardiovascular parameter (HR, SBP, DBP, or RSA) as a dependent variable. Extraversion (NEO-FFI), subjective stress, and physiological stress were measured in 166 undergraduate students randomly assigned to undergo moderate (n=82) or high-intensity (n=84) social stress (a public speaking task with different levels of social evaluation). All participants underwent continuous physiological monitoring while facing two consecutive stress exposures distributed across five laboratory phases: baseline, stress exposure 1, post-stress 1, stress exposure 2, post-stress 2. Results indicated that under moderate-intensity social stress, participants higher on extraversion exhibited lesser HR reactivity to stress than participants lower on extraversion, while under high-intensity social stress, they exhibited greater HR, SBP, DBP and RSA reactivity. Under both moderate- and high-intensity social stress, participants higher on extraversion exhibited pronounced SBP and DBP response adaptation to repeated stress, and showed either better degree of HR recovery or greater amount of SBP and DBP recovery after stress. These findings suggest that individuals higher on extraversion exhibit physiological flexibility to cope with social challenges and benefit from adaptive cardiovascular responses. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of different seasons during late gestation on Holstein cows' colostrum and postnatal adaptive capability of their calves.

PubMed

Trifković, Julijana; Jovanović, Ljubomir; Đurić, Miloje; Stevanović-Đorđević, Snežana; Milanović, Svetlana; Lazarević, Miodrag; Sladojević, Željko; Kirovski, Danijela

2018-06-01

Season may affect calves' thermal comfort and behavior, but the data related to the overall influence of seasonal variations on dams' colostrum and postnatal adaptive capability of calves are limited. The aim of this study was to measure the effects of a 49-day-long low air temperature (LAT) season (5.20 ± 0.46 °C mean air temperature) and a 53-day-long high air temperature (HAT) season (27.40 ± 0.39 °C mean air temperature) on dams' colostrum quality and physiological, biochemical, hormonal, and oxidative stress parameters of their calves during the first 7 days of life. The dams' colostrum was sampled at 2, 14, and 26 h after calving, before feeding of their calves. Calves' blood samples were taken before the first colostrum intake and on days 1, 2, 3, and 7 of life. Calves' physiological parameters were measured on days 0 and 7. HAT season significantly reduced the quality of dams' colostrum. The ingestion of the low-quality colostrum, combined with the thermal discomfort during HAT season, probably provoked impaired physiological, biochemical, hormonal, and oxidative stress parameters in samples taken from the post-colostral calves. Additionally, intravenous glucose tolerance test was performed on day 7, which suggested an enhanced insulin response in HAT season calves. This study highlights the importance of adequate supporting strategies for the care of the late gestation cows and postnatal calves during the HAT season.

Influence of different seasons during late gestation on Holstein cows' colostrum and postnatal adaptive capability of their calves

NASA Astrophysics Data System (ADS)

Trifković, Julijana; Jovanović, Ljubomir; Đurić, Miloje; Stevanović-Đorđević, Snežana; Milanović, Svetlana; Lazarević, Miodrag; Sladojević, Željko; Kirovski, Danijela

2018-02-01

Season may affect calves' thermal comfort and behavior, but the data related to the overall influence of seasonal variations on dams' colostrum and postnatal adaptive capability of calves are limited. The aim of this study was to measure the effects of a 49-day-long low air temperature (LAT) season (5.20 ± 0.46 °C mean air temperature) and a 53-day-long high air temperature (HAT) season (27.40 ± 0.39 °C mean air temperature) on dams' colostrum quality and physiological, biochemical, hormonal, and oxidative stress parameters of their calves during the first 7 days of life. The dams' colostrum was sampled at 2, 14, and 26 h after calving, before feeding of their calves. Calves' blood samples were taken before the first colostrum intake and on days 1, 2, 3, and 7 of life. Calves' physiological parameters were measured on days 0 and 7. HAT season significantly reduced the quality of dams' colostrum. The ingestion of the low-quality colostrum, combined with the thermal discomfort during HAT season, probably provoked impaired physiological, biochemical, hormonal, and oxidative stress parameters in samples taken from the post-colostral calves. Additionally, intravenous glucose tolerance test was performed on day 7, which suggested an enhanced insulin response in HAT season calves. This study highlights the importance of adequate supporting strategies for the care of the late gestation cows and postnatal calves during the HAT season.

Physiological differences between various types of Eisenmenger syndrome and relation to outcome.

PubMed

Moceri, Pamela; Kempny, Aleksander; Liodakis, Emmanouil; Alonso Gonzales, Rafael; Germanakis, Ioannis; Diller, Gerhard-Paul; Swan, Lorna; Marino, Philip S; Wort, Stephen J; Babu-Narayan, Sonya V; Ferrari, Emile; Gatzoulis, Michael A; Li, Wei; Dimopoulos, Konstantinos

2015-01-20

Eisenmenger syndrome (ES) is the most advanced form of pulmonary arterial hypertension (PAH) related to congenital heart disease. Several studies have suggested that the presence and location of the shunt defines the natural history of these patients by influencing right ventricular adaptation to PAH. We aimed to echocardiographically assess differences in cardiac physiology and outcome between various types of ES. In this longitudinal cohort study, 191 patients with ES and non-complex congenital heart disease were recruited, 36 with pre-tricuspid and 155 with post-tricuspid shunts. Patients with pre-tricuspid shunts were older, had higher BNP concentrations and lower exercise tolerance compared to patients with post-tricuspid shunts. Right ventricular (RV) function was impaired in patients with atrial septal defects, with larger right ventricles, impaired systolic function and adaptation. The left ventricular eccentricity index was significantly higher in pre-tricuspid defects. Within post-tricuspid shunts, patients with atrio-ventricular septal defects had better right ventricular function compared to ventricular septal defects, while in those with a patent ductus arteriosus this was worse. There was a trend towards lower mortality in patients with post versus pre-tricuspid shunts, which was significant for patients above the age of 48 years. The presence of a post-tricuspid shunt appears to carry physiological and possibly prognostic benefits in ES compared to patients with pre-tricuspid shunts. This should be borne in mind when management decisions and advanced therapies are considered. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Microbial Response to Microgravity and Other Low Shear Environments

NASA Technical Reports Server (NTRS)

Nickerson, C.; Ott, C. Mark; Wilson, James W.; Ramamurthy, Rajee; Pierson, Duane L.

2004-01-01

Microbial existence and survival requires the ability to sense and respond to environmental changes, including changes in physical forces. This is because microbes inhabit an amazingly diverse range of ecological niches and therefore must constantly adapt to a wide variety of changing environmental conditions, including alterations in temperature, pH, nutrient availability, oxygen levels, and osmotic pressure gradients. Microbes sense their environment through a variety of sensors and receptors which serve to integrate the different signals into the appropriate cellular response(s) that is optimal for survival. While numerous environmental stimuli have been examined for their effect on microorganisms, effects due to changes in mechanical and/or physical forces are also becoming increasingly apparent. Recently, several important studies have demonstrated a key role for microgravity and the low fluid shear dynamics associated with microgravity in the regulation of microbial gene expression, physiology and pathogenesis. The mechanosensory response of microorganisms to these environmental signals, which are relevant to those encountered during microbial life cycles on Earth, may provide insight into their adaptations to physiologically relevant conditions and may ultimately lead to eludicidation of the mechanisms important for mechanosensory transduction in living cells. This review summarizes the recent and potential future research trends aimed at understanding the effect of changes in mechanical forces that occur in microgravity and other low shear environments on different microbial parameters. The results of these studies provide an important step towards understanding how microbes integrate information from multiple mechanical stimuli to an appropriate physiological response.

Human adaptation genetic response suites: Toward new interventions and countermeasures for spaceflight

NASA Astrophysics Data System (ADS)

Sundaresan, A.; Pellis, N. R.

2005-08-01

Genetic response suites in human lymphocytes in response to microgravity are important to identify and further study in order to augment human physiological adaptation to novel environments. Emerging technologies, such as DNA micro array profiling, have the potential to identify novel genes that are involved in mediating adaptation to these environments. These genes may prove to be therapeutically valuable as new targets for countermeasures, or as predictive biomarkers of response to these new environments. Human lymphocytes cultured in 1g and microgravity analog culture were analyzed for their differential gene expression response. Different groups of genes related to the immune response, cardiovascular system and stress response were then analyzed. Analysis of cells from multiple donors reveals a small shared set that are likely to be essential to adaptation. These three groups focus on human adaptation to new environments. The shared set contains genes related to T cell activation, immune response and stress response to analog microgravity.

Origins of Allostery and Evolvability in Proteins: A Case Study.

PubMed

Raman, Arjun S; White, K Ian; Ranganathan, Rama

2016-07-14

Proteins display the capacity for adaptation to new functions, a property critical for evolvability. But what structural principles underlie the capacity for adaptation? Here, we show that adaptation to a physiologically distinct class of ligand specificity in a PSD95, DLG1, ZO-1 (PDZ) domain preferentially occurs through class-bridging intermediate mutations located distant from the ligand-binding site. These mutations provide a functional link between ligand classes and demonstrate the principle of "conditional neutrality" in mediating evolutionary adaptation. Structures show that class-bridging mutations work allosterically to open up conformational plasticity at the active site, permitting novel functions while retaining existing function. More generally, the class-bridging phenotype arises from mutations in an evolutionarily conserved network of coevolving amino acids in the PDZ family (the sector) that connects the active site to distant surface sites. These findings introduce the concept that allostery in proteins could have its origins not in protein function but in the capacity to adapt. Copyright © 2016 Elsevier Inc. All rights reserved.

Physiological Arousal, Distress Tolerance, and Social Problem-Solving Deficits among Adolescent Self-Injurers

ERIC Educational Resources Information Center

Nock, Matthew K.; Mendes, Wendy Berry

2008-01-01

It has been suggested that people engage in nonsuicidal self-injury (NSSI) because they (a) experience heightened physiological arousal following stressful events and use NSSI to regulate experienced distress and (b) have deficits in their social problem-solving skills that interfere with the performance of more adaptive social responses. However,…

Physiological effects of Meloidogyne incognita infection on cotton genotypes with differing levels of resistance in the greenhouse

USDA-ARS?s Scientific Manuscript database

Greenhouse tests were conducted to evaluate 1) the effect of Meloidogyne incognita infection in cotton on plant growth and physiology including the height-to-node ratio, chlorophyll content, dark adapted quantum yield of photosystem II, and leaf area, and 2) the extent to which moderate or high leve...

Physiological response of the lichen Phaeophyscia hispidula (Ach.) Essl., to the urban environment of Pauri and Srinagar (Garhwal), Himalayas, India.

PubMed

Shukla, Vertika; Upreti, Dalip K

2007-12-01

The present study was designed with an aim to observe the effect of increasing urbanization and traffic activity on the physiology of a foliose lichen, Phaeophyscia hispidula (Ach.) Essl., collected from 13 different localities, growing in their natural habitat, in Pauri and Srinagar, two cities in the Himalayas. Six parameters i.e., Chl. a, Chl. b, total pigment, chlorophyll degradation, carotenoid and total protein content, proved the most useful to assess air pollution, were measured. Chlorophyll content and protein content are an efficient parameter to measure the air quality of a region. The study indicates that P. hispidula is pollution tolerant (adaptation) and able to withstand local emissions from vehicle exhausts.

Performance characteristics of long-track speed skaters: a literature review.

PubMed

Konings, Marco J; Elferink-Gemser, Marije T; Stoter, Inge K; van der Meer, Dirk; Otten, Egbert; Hettinga, Florentina J

2015-04-01

Speed skating is an intriguing sport to study from different perspectives due to the peculiar way of motion and the multiple determinants for performance. This review aimed to identify what is known on (long-track) speed skating, and which individual characteristics determine speed skating performance. A total of 49 studies were included. Based on a multidimensional performance model, person-related performance characteristics were categorized in anthropometrical, technical, physiological, tactical, and psychological characteristics. Literature was found on anthropometry, technique, physiology, and tactics. However, psychological studies were clearly under-represented. In particular, the role of self-regulation might deserve more attention to further understand mechanisms relevant for optimal performance and for instance pacing. Another remarkable finding was that the technically/biomechanically favourable crouched skating technique (i.e. small knee and trunk angle) leads to a physiological disadvantage: a smaller knee angle may increase the deoxygenation of the working muscles. This is an important underlying aspect for the pacing tactics in speed skating. Elite speed skaters need to find the optimal balance between obtaining a fast start and preventing negative technical adaptations later on in the race by distributing their available energy over the race in an optimal way. More research is required to gain more insight into how this impacts on the processes of fatigue and coordination during speed skating races. This can lead to a better understanding on how elite speed skaters can maintain the optimal technical characteristics throughout the entire race, and how they can adapt their pacing to optimize all identified aspects that determine performance.

Converging Indicators for Assessing Individual Differences in Adaptation to Extreme Environments: Preliminary Report

NASA Technical Reports Server (NTRS)

Cowings, Patricia S.; Toscano, William B.; DeRoshia, Charles W.; Taylor, Bruce; Hines, Seleimah; Bright, Andrew; Dodds, Anika

2006-01-01

This paper describes the development and validation of a new methodology for assessing the deleterious effects of spaceflight on crew health and performance. It is well known that microgravity results in various physiological alterations, e.g., headward fluid shifts which can impede physiological adaptation. Other factors that may affect crew operational efficiency include disruption of sleep-wake cycles, high workload, isolation, confinement, stress and fatigue. From an operational perspective, it is difficult to predict which individuals will be most or least affected in this unique environment given that most astronauts are first-time flyers. During future lunar and Mars missions space crews will include both men and women of multi-national origins, different professional backgrounds, and various states of physical condition. Therefore, new methods or technologies are needed to monitor and predict astronaut performance and health, and to evaluate the effects of various countermeasures on crew during long duration missions. This paper reviews several studies conducted in both laboratory and operational environments with men and women ranging in age between 18 to 50 years. The studies included the following: soldiers performing command and control functions during mobile operations in enclosed armored vehicles; subjects participating in laboratory tests of an anti-motion sickness medication; subjects exposed to chronic hypergravity aboard a centrifuge, and subject responses to 36-hours of sleep deprivation. Physiological measurements, performance metrics, and subjective self-reports were collected in each study. The results demonstrate that multivariate converging indicators provide a significantly more reliable method for assessing environmental effects on performance and health than any single indicator.

Muscle transcriptome response to ACTH administration in a free-ranging marine mammal

PubMed Central

Champagne, Cory D.; Preeyanon, Likit; Ortiz, Rudy M.; Crocker, Daniel E.

2015-01-01

While much of our understanding of stress physiology is derived from biomedical studies, little is known about the downstream molecular consequences of adaptive stress responses in free-living animals. We examined molecular effectors of the stress hormones cortisol and aldosterone in the northern elephant seal, a free-ranging study system in which extreme physiological challenges and cortisol fluctuations are a routine part of life history. We stimulated the neuroendocrine stress axis by administering exogenous adrenocorticotropic hormone (ACTH) and examined the resultant effects by measuring corticosteroid hormones, metabolites, and gene expression before, during, and following administration. ACTH induced an elevation in cortisol, aldosterone, glucose, and fatty acids within 2 h, with complete recovery observed within 24 h of administration. The global transcriptional response of elephant seal muscle tissue to ACTH was evaluated by transcriptomics and involved upregulation of a highly coordinated network of conserved glucocorticoid (GC) target genes predicted to promote metabolic substrate availability without causing deleterious effects seen in laboratory animals. Transcriptional recovery from ACTH was characterized by downregulation of GC target genes and restoration of cell proliferation, metabolism, and tissue maintenance pathways within 24 h. Differentially expressed genes included several adipokines not previously described in muscle, reflecting unique metabolic physiology in fasting-adapted animals. This study represents one of the first transcriptome analyses of cellular responses to hypothalamic-pituitary-adrenal axis stimulation in a free-living marine mammal and suggests that compensatory, tissue-sparing mechanisms may enable marine mammals to maintain cortisol and aldosterone sensitivity while avoiding deleterious long-term consequences of stress. PMID:26038394

Monte Carlo study for physiological interference reduction in near-infrared spectroscopy based on empirical mode decomposition

NASA Astrophysics Data System (ADS)

Zhang, Yan; Sun, JinWei; Rolfe, Peter

2010-12-01

Near-infrared spectroscopy (NIRS) can be used as the basis of non-invasive neuroimaging that may allow the measurement of haemodynamic changes in the human brain evoked by applied stimuli. Since this technique is very sensitive, physiological interference arising from the cardiac cycle and breathing can significantly affect the signal quality. Such interference is difficult to remove by conventional techniques because it occurs not only in the extracerebral layer but also in the brain tissue itself. Previous work on this problem employing temporal filtering, spatial filtering, and adaptive filtering have exhibited good performance for recovering brain activity data in evoked response studies. However, in this study, we present a time-frequency adaptive method for physiological interference reduction based on the combination of empirical mode decomposition (EMD) and Hilbert spectral analysis (HSA). Monte Carlo simulations based on a five-layered slab model of a human adult head were implemented to evaluate our methodology. We applied an EMD algorithm to decompose the NIRS time series derived from Monte Carlo simulations into a series of intrinsic mode functions (IMFs). In order to identify the IMFs associated with symmetric interference, the extracted components were then Hilbert transformed from which the instantaneous frequencies could be acquired. By reconstructing the NIRS signal by properly selecting IMFs, we determined that the evoked brain response is effectively filtered out with even higher signal-to-noise ratio (SNR). The results obtained demonstrated that EMD, combined with HSA, can effectively separate, identify and remove the contamination from the evoked brain response obtained with NIRS using a simple single source-detector pair.

Biotic and Abiotic Interactions of Deep-Sea Hydrothermal Vent-Endemic Fish on the East Pacific Rise

DTIC Science & Technology

2009-09-01

physiological and ecological adaptations these fauna have to their environment (Childress & Fisher, 1992; Hourdez & Lallier, 2007). 1.2 East Pacific...inability of non-vent fauna to adapt to and offset the affects of the shifting and potentially harmful chemical environment, including potential prey items...some sort of adaptation to meet the challenges present within their habitat, including the presence of high levels of hydrogen sulfide, high

Abstracts of Papers Submitted in 1975 for Publication,

DTIC Science & Technology

1975-01-01

Supported by NSF Grant GA-35393) Temporal Adaptations in Sibling Species of Capitetla . .B-20 J. Frederick Grassle, Judith P. Grassle, Rudolph S. Sheltema...Charlene D. Van Raalte and Edward J. Carpenter (Supported by NSF Grant GA-43008) Physiological Adaptations of Marsh Animals to a Hydrocarbon-Polluted Envi...therapy prior to hospitalization did not vitiate the validity of the test. A bedside adaptation of the limulus test, performed by house officers and

A global bioheat model with self-tuning optimal regulation of body temperature using Hebbian feedback covariance learning.

PubMed

Ong, M L; Ng, E Y K

2005-12-01

In the lower brain, body temperature is continually being regulated almost flawlessly despite huge fluctuations in ambient and physiological conditions that constantly threaten the well-being of the body. The underlying control problem defining thermal homeostasis is one of great enormity: Many systems and sub-systems are involved in temperature regulation and physiological processes are intrinsically complex and intertwined. Thus the defining control system has to take into account the complications of nonlinearities, system uncertainties, delayed feedback loops as well as internal and external disturbances. In this paper, we propose a self-tuning adaptive thermal controller based upon Hebbian feedback covariance learning where the system is to be regulated continually to best suit its environment. This hypothesis is supported in part by postulations of the presence of adaptive optimization behavior in biological systems of certain organisms which face limited resources vital for survival. We demonstrate the use of Hebbian feedback covariance learning as a possible self-adaptive controller in body temperature regulation. The model postulates an important role of Hebbian covariance adaptation as a means of reinforcement learning in the thermal controller. The passive system is based on a simplified 2-node core and shell representation of the body, where global responses are captured. Model predictions are consistent with observed thermoregulatory responses to conditions of exercise and rest, and heat and cold stress. An important implication of the model is that optimal physiological behaviors arising from self-tuning adaptive regulation in the thermal controller may be responsible for the departure from homeostasis in abnormal states, e.g., fever. This was previously unexplained using the conventional "set-point" control theory.

Interannual physiological and growth responses of glacial Juniperus to changes in atmospheric [CO2] since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Gerhart, L. M.; Harris, J. M.; Ward, J. K.

2011-12-01

During the Last Glacial Maximum, atmospheric [CO2] was as low as 180 ppm and has currently risen to a modern value of 393 ppm as a result of fossil fuel combustion and deforestation. In order to understand how changing [CO2] influenced trees over the last 50,000 years, we analyzed carbon isotope ratios and width of individual tree rings from glacial Juniperus specimens preserved in the Rancho La Brea tar pits in southern California (aged 14-49 kyr BP). Modern trees were also analyzed to compare effects of changing precipitation, temperature and atmospheric [CO2] on physiology and growth. To assess physiological responses, we calculated ci/ca (intercellular [CO2]/atmospheric [CO2]) for each annual ring of each tree. This ratio incorporates numerous aspects of plant physiology, including stomatal conductance and photosynthetic capacity. In addition, we measured ring widths for each sample, and standardized these measurements into indices in order to compare across individuals. Mean ci/ca values remained constant throughout 50,000 years despite major environmental changes, indicating a long-term physiological set point for ci/ca in this group. Constant ci/ca ratios would be maintained through offsetting changes in stomatal conductance and photosynthetic capacity. Glacial Juniperus never experienced ci values below 90 ppm, suggesting a survival compensation point for Juniperus. In addition, glacial trees showed significantly reduced interannual variation in ci/ca, even though interannual climatic variability was as high during the LGM in this region as it is today. A lack of variability in ci/ca of glacial trees suggests that tree physiology was dominated by low [CO2], which shows low interannual variation. Modern trees showed high interannual variation in ci/ca, since water availability dominates current physiological responses and varies greatly from year to year. Interestingly, interannual variation in ring width index did not show significant differences between glacial and modern trees, suggesting these trees were adapted to maintain growth under low [CO2]. These adaptations may constrain the ability of modern trees to fully utilize increases in atmospheric [CO2]. These results have significant implications for our understanding of the adaptations of trees to changing [CO2] and indicate that the environmental factors that most strongly influence plant physiology may have changed over geologic time scales.

Behaviorally Mediated, Warm Adaptation: A Physiological Strategy When Mice Are Allowed to Behaviorally Thermoregulate

EPA Science Inventory

Laboratory mice housed under standard vivarium conditions with an ambient temperature (Ta) of -22°C are likely to be cold stressed because this Ta is below their thermoneutral zone (TNZ). Mice raised at Tas within the TNZ adapt to the warmer temperatures, developing smaller int...

An international collaboration studying the physiological and anatomical cerebral effects of carbon dioxide during head-down tilt bed rest: the SPACECOT study.

PubMed

Marshall-Goebel, Karina; Mulder, Edwin; Donoviel, Dorit; Strangman, Gary; Suarez, Jose I; Venkatasubba Rao, Chethan; Frings-Meuthen, Petra; Limper, Ulrich; Rittweger, Jörn; Bershad, Eric M

2017-06-01

Exposure to the microgravity environment results in various adaptive and maladaptive physiological changes in the human body, with notable ophthalmic abnormalities developing during 6-mo missions on the International Space Station (ISS). These findings have led to the hypothesis that the loss of gravity induces a cephalad fluid shift, decreased cerebral venous outflow, and increased intracranial pressure, which may be further exacerbated by increased ambient carbon dioxide (CO 2 ) levels on the ISS. Here we describe the SPACECOT study (studying the physiological and anatomical cerebral effects of CO 2 during head-down tilt), a randomized, double-blind crossover design study with two conditions: 29 h of 12° head-down tilt (HDT) with ambient air and 29 h of 12° HDT with 0.5% CO 2 The internationally collaborative SPACECOT study utilized an innovative approach to study the effects of headward fluid shifting induced by 12° HDT and increased ambient CO 2 as well as their interaction with a focus on cerebral and ocular anatomy and physiology. Here we provide an in-depth overview of this new approach including the subjects, study design, and implementation, as well as the standardization plan for nutritional intake, environmental parameters, and bed rest procedures. NEW & NOTEWORTHY A new approach for investigating the combined effects of cephalad fluid shifting and increased ambient carbon dioxide (CO 2 ) is presented. This may be useful for studying the neuroophthalmic and cerebral effects of spaceflight where cephalad fluid shifts occur in an elevated CO 2 environment. Copyright © 2017 the American Physiological Society.

Adaptations to Hydrothermal Vent Life in Kiwa tyleri, a New Species of Yeti Crab from the East Scotia Ridge, Antarctica.

PubMed

Thatje, Sven; Marsh, Leigh; Roterman, Christopher Nicolai; Mavrogordato, Mark N; Linse, Katrin

2015-01-01

Hydrothermal vents in the Southern Ocean are the physiologically most isolated chemosynthetic environments known. Here, we describe Kiwa tyleri sp. nov., the first species of yeti crab known from the Southern Ocean. Kiwa tyleri belongs to the family Kiwaidae and is the visually dominant macrofauna of two known vent sites situated on the northern and southern segments of the East Scotia Ridge (ESR). The species is known to depend on primary productivity by chemosynthetic bacteria and resides at the warm-eurythermal vent environment for most of its life; its short-range distribution away from vents (few metres) is physiologically constrained by the stable, cold waters of the surrounding Southern Ocean. Kiwa tylerihas been shown to present differential life history adaptations in response to this contrasting thermal environment. Morphological adaptations specific to life in warm-eurythermal waters, as found on - or in close proximity of - vent chimneys, are discussed in comparison with adaptations seen in the other two known members of the family (K. hirsuta, K. puravida), which show a preference for low temperature chemosynthetic environments.

Vascularization of Air Sinuses and Fat Bodies in the Head of the Bottlenose Dolphin (Tursiops truncatus): Morphological Implications on Physiology

PubMed Central

Costidis, Alex; Rommel, Sentiel A.

2012-01-01

Cetaceans have long been considered capable of limiting diving-induced nitrogen absorption and subsequent decompression sickness through a series of behavioral, anatomical, and physiological adaptations. Recent studies however suggest that in some situations these adaptive mechanisms might be overcome, resulting in lethal and sublethal injuries. Perhaps most relevant to this discussion is the finding of intravascular gas and fat emboli in mass-stranded beaked whales. Although the source of the gas emboli has as yet to been ascertained, preliminary findings suggest nitrogen is the primary component. Since nitrogen gas embolus formation in divers is linked to nitrogen saturation, it seems premature to dismiss similar pathogenic mechanisms in breath-hold diving cetaceans. Due to the various anatomical adaptations in cetacean lungs, the pulmonary system is thought of as an unlikely site of significant nitrogen absorption. The accessory sinus system on the ventral head of odontocete cetaceans contains a sizeable volume of air that is exposed to the changing hydrostatic pressures during a dive, and is intimately associated with vasculature potentially capable of absorbing nitrogen through its walls. The source of the fat emboli has also remained elusive. Most mammalian fat deposits are considered poorly vascularized and therefore unlikely sites of intravascular introduction of lipid, although cetacean blubber may not be as poorly vascularized as previously thought. We present new data on the vasculature of air sinuses and acoustic fat bodies in the head of bottlenose dolphins and compare it to published accounts. We show that the mandibular fat bodies and accessory sinus system are associated with extensive venous plexuses and suggest potential physiological and pathological implications. PMID:22969724

Characteristic Metabolism of Free Amino Acids in Cetacean Plasma: Cluster Analysis and Comparison with Mice

PubMed Central

Miyaji, Kazuki; Nagao, Kenji; Bannai, Makoto; Asakawa, Hiroshi; Kohyama, Kaoru; Ohtsu, Dai; Terasawa, Fumio; Ito, Shu; Iwao, Hajime; Ohtani, Nobuyo; Ohta, Mitsuaki

2010-01-01

From an evolutionary perspective, the ancestors of cetaceans first lived in terrestrial environments prior to adapting to aquatic environments. Whereas anatomical and morphological adaptations to aquatic environments have been well studied, few studies have focused on physiological changes. We focused on plasma amino acid concentrations (aminograms) since they show distinct patterns under various physiological conditions. Plasma and urine aminograms were obtained from bottlenose dolphins, pacific white-sided dolphins, Risso's dolphins, false-killer whales and C57BL/6J and ICR mice. Hierarchical cluster analyses were employed to uncover a multitude of amino acid relationships among different species, which can help us understand the complex interrelations comprising metabolic adaptations. The cetacean aminograms formed a cluster that was markedly distinguishable from the mouse cluster, indicating that cetaceans and terrestrial mammals have quite different metabolic machinery for amino acids. Levels of carnosine and 3-methylhistidine, both of which are antioxidants, were substantially higher in cetaceans. Urea was markedly elevated in cetaceans, whereas the level of urea cycle-related amino acids was lower. Because diving mammals must cope with high rates of reactive oxygen species generation due to alterations in apnea/reoxygenation and ischemia-reperfusion processes, high concentrations of antioxidative amino acids are advantageous. Moreover, shifting the set point of urea cycle may be an adaption used for body water conservation in the hyperosmotic sea water environment, because urea functions as a major blood osmolyte. Furthermore, since dolphins are kept in many aquariums for observation, the evaluation of these aminograms may provide useful diagnostic indices for the assessment of cetacean health in artificial environments in the future. PMID:21072195

The locus of evolution: evo devo and the genetics of adaptation.

PubMed

Hoekstra, Hopi E; Coyne, Jerry A

2007-05-01

An important tenet of evolutionary developmental biology ("evo devo") is that adaptive mutations affecting morphology are more likely to occur in the cis-regulatory regions than in the protein-coding regions of genes. This argument rests on two claims: (1) the modular nature of cis-regulatory elements largely frees them from deleterious pleiotropic effects, and (2) a growing body of empirical evidence appears to support the predominant role of gene regulatory change in adaptation, especially morphological adaptation. Here we discuss and critique these assertions. We first show that there is no theoretical or empirical basis for the evo devo contention that adaptations involving morphology evolve by genetic mechanisms different from those involving physiology and other traits. In addition, some forms of protein evolution can avoid the negative consequences of pleiotropy, most notably via gene duplication. In light of evo devo claims, we then examine the substantial data on the genetic basis of adaptation from both genome-wide surveys and single-locus studies. Genomic studies lend little support to the cis-regulatory theory: many of these have detected adaptation in protein-coding regions, including transcription factors, whereas few have examined regulatory regions. Turning to single-locus studies, we note that the most widely cited examples of adaptive cis-regulatory mutations focus on trait loss rather than gain, and none have yet pinpointed an evolved regulatory site. In contrast, there are many studies that have both identified structural mutations and functionally verified their contribution to adaptation and speciation. Neither the theoretical arguments nor the data from nature, then, support the claim for a predominance of cis-regulatory mutations in evolution. Although this claim may be true, it is at best premature. Adaptation and speciation probably proceed through a combination of cis-regulatory and structural mutations, with a substantial contribution of the latter.

Identifying traits for genotypic adaptation using crop models.

PubMed

Ramirez-Villegas, Julian; Watson, James; Challinor, Andrew J

2015-06-01

Genotypic adaptation involves the incorporation of novel traits in crop varieties so as to enhance food productivity and stability and is expected to be one of the most important adaptation strategies to future climate change. Simulation modelling can provide the basis for evaluating the biophysical potential of crop traits for genotypic adaptation. This review focuses on the use of models for assessing the potential benefits of genotypic adaptation as a response strategy to projected climate change impacts. Some key crop responses to the environment, as well as the role of models and model ensembles for assessing impacts and adaptation, are first reviewed. Next, the review describes crop-climate models can help focus the development of future-adapted crop germplasm in breeding programmes. While recently published modelling studies have demonstrated the potential of genotypic adaptation strategies and ideotype design, it is argued that, for model-based studies of genotypic adaptation to be used in crop breeding, it is critical that modelled traits are better grounded in genetic and physiological knowledge. To this aim, two main goals need to be pursued in future studies: (i) a better understanding of plant processes that limit productivity under future climate change; and (ii) a coupling between genetic and crop growth models-perhaps at the expense of the number of traits analysed. Importantly, the latter may imply additional complexity (and likely uncertainty) in crop modelling studies. Hence, appropriately constraining processes and parameters in models and a shift from simply quantifying uncertainty to actually quantifying robustness towards modelling choices are two key aspects that need to be included into future crop model-based analyses of genotypic adaptation. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

[Adaptive optics for ophthalmology].

PubMed

Saleh, M

2016-04-01

Adaptive optics is a technology enhancing the visual performance of an optical system by correcting its optical aberrations. Adaptive optics have already enabled several breakthroughs in the field of visual sciences, such as improvement of visual acuity in normal and diseased eyes beyond physiologic limits, and the correction of presbyopia. Adaptive optics technology also provides high-resolution, in vivo imaging of the retina that may eventually help to detect the onset of retinal conditions at an early stage and provide better assessment of treatment efficacy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Cenozoic climate change shaped the evolutionary ecophysiology of the Cupressaceae conifers

PubMed Central

Pittermann, Jarmila; Stuart, Stephanie A.; Dawson, Todd E.; Moreau, Astrid

2012-01-01

The Cupressaceae clade has the broadest diversity in habitat and morphology of any conifer family. This clade is characterized by highly divergent physiological strategies, with deciduous swamp-adapted genera-like Taxodium at one extreme, and evergreen desert genera-like Cupressus at the other. The size disparity within the Cupressaceae is equally impressive, with members ranging from 5-m-tall juniper shrubs to 100-m-tall redwood trees. Phylogenetic studies demonstrate that despite this variation, these taxa all share a single common ancestor; by extension, they also share a common ancestral habitat. Here, we use a common-garden approach to compare xylem and leaf-level physiology in this family. We then apply comparative phylogenetic methods to infer how Cenozoic climatic change shaped the morphological and physiological differences between modern-day members of the Cupressaceae. Our data show that drought-resistant crown clades (the Cupressoid and Callitroid clades) most likely evolved from drought-intolerant Mesozoic ancestors, and that this pattern is consistent with proposed shifts in post-Eocene paleoclimates. We also provide evidence that within the Cupressaceae, the evolution of drought-resistant xylem is coupled to increased carbon investment in xylem tissue, reduced xylem transport efficiency, and at the leaf level, reduced photosynthetic capacity. Phylogenetically based analyses suggest that the ancestors of the Cupressaceae were dependent upon moist habitats, and that drought-resistant physiology developed along with increasing habitat aridity from the Oligocene onward. We conclude that the modern biogeography of the Cupressaceae conifers was shaped in large part by their capacity to adapt to drought. PMID:22628565

Cenozoic climate change shaped the evolutionary ecophysiology of the Cupressaceae conifers.

PubMed

Pittermann, Jarmila; Stuart, Stephanie A; Dawson, Todd E; Moreau, Astrid

2012-06-12

The Cupressaceae clade has the broadest diversity in habitat and morphology of any conifer family. This clade is characterized by highly divergent physiological strategies, with deciduous swamp-adapted genera-like Taxodium at one extreme, and evergreen desert genera-like Cupressus at the other. The size disparity within the Cupressaceae is equally impressive, with members ranging from 5-m-tall juniper shrubs to 100-m-tall redwood trees. Phylogenetic studies demonstrate that despite this variation, these taxa all share a single common ancestor; by extension, they also share a common ancestral habitat. Here, we use a common-garden approach to compare xylem and leaf-level physiology in this family. We then apply comparative phylogenetic methods to infer how Cenozoic climatic change shaped the morphological and physiological differences between modern-day members of the Cupressaceae. Our data show that drought-resistant crown clades (the Cupressoid and Callitroid clades) most likely evolved from drought-intolerant Mesozoic ancestors, and that this pattern is consistent with proposed shifts in post-Eocene paleoclimates. We also provide evidence that within the Cupressaceae, the evolution of drought-resistant xylem is coupled to increased carbon investment in xylem tissue, reduced xylem transport efficiency, and at the leaf level, reduced photosynthetic capacity. Phylogenetically based analyses suggest that the ancestors of the Cupressaceae were dependent upon moist habitats, and that drought-resistant physiology developed along with increasing habitat aridity from the Oligocene onward. We conclude that the modern biogeography of the Cupressaceae conifers was shaped in large part by their capacity to adapt to drought.

Artificial blood circulation: stabilization, physiological control, and optimization.

PubMed

Lerner, A Y

1990-04-01

The requirements for creating an efficient Artificial Blood Circulation System (ABCS) have been determined. A hierarchical three-level adaptive control system is suggested for ABCS to solve the following problems: stabilization of the circulation conditions, left and right pump coordination, physiological control for maintaining a proper relation between the cardiac output and the level of gas exchange required for metabolism, and optimization of the system behavior. The adaptations to varying load and body parameters will be accomplished using the signals which characterize the real-time computer-processed values of correlations between the changes in hydraulic resistance of blood vessels, or the changes in aortic pressure, and the oxygen (or carbon dioxide) concentration.

Mechanisms of Cardiopulmonary Adaptation to Microgravity. Part 1

NASA Technical Reports Server (NTRS)

1997-01-01

Session TA1 includes short reports covering: (1) Indices of Baroreceptor Reflex Sensitivity: The Use in Rehabilitation Medicine and Space Cardiology; (2) +Gz and +Gx Tolerance of Healthy Persons of Non-Flying Trades at Primary Selection of the Centrifuge; (3) Effect of Dry Immersion on Calf Blood Supply During Sustained Contraction and Upright Exercise in Man; (4) Cardiovascular and Valsalva Responses during Parabolic flight; (5) An Analysis of the Cardiovascular Responses under Hyper- and Hypo-Gravity Environments using a Mathematical model; (6) Effect of Very Gradual Onset Rate +Gz Exposures on the Cardiovascular System; and (7) NASA Specialized Center of Research and Training (NSCORT) in Integrated Physiology: Mechanisms of Physiological Adaptations to Microgravity.

Influence of dietary nitrate supplementation on physiological and muscle metabolic adaptations to sprint interval training

PubMed Central

Thompson, Christopher; Wylie, Lee J.; Blackwell, Jamie R.; Fulford, Jonathan; Black, Matthew I.; Kelly, James; McDonagh, Sinead T. J.; Carter, James; Bailey, Stephen J.; Vanhatalo, Anni

2017-01-01

We hypothesized that 4 wk of dietary nitrate supplementation would enhance exercise performance and muscle metabolic adaptations to sprint interval training (SIT). Thirty-six recreationally active subjects, matched on key variables at baseline, completed a series of exercise tests before and following a 4-wk period in which they were allocated to one of the following groups: 1) SIT and NO3−-depleted beetroot juice as a placebo (SIT+PL); 2) SIT and NO3−-rich beetroot juice (~13 mmol NO3−/day; SIT+BR); or 3) no training and NO3−-rich beetroot juice (NT+BR). During moderate-intensity exercise, pulmonary oxygen uptake was reduced by 4% following 4 wk of SIT+BR and NT+BR (P < 0.05) but not SIT+PL. The peak work rate attained during incremental exercise increased more in SIT+BR than in SIT+PL (P < 0.05) or NT+BR (P < 0.001). The reduction in muscle and blood [lactate] and the increase in muscle pH from preintervention to postintervention were greater at 3 min of severe-intensity exercise in SIT+BR compared with SIT+PL and NT+BR (P < 0.05). However, the change in severe-intensity exercise performance was not different between SIT+BR and SIT+PL (P > 0.05). The relative proportion of type IIx muscle fibers in the vastus lateralis muscle was reduced in SIT+BR only (P < 0.05). These findings suggest that BR supplementation may enhance some aspects of the physiological adaptations to SIT. NEW & NOTEWORTHY We investigated the influence of nitrate-rich and nitrate-depleted beetroot juice on the muscle metabolic and physiological adaptations to 4 wk of sprint interval training. Compared with placebo, dietary nitrate supplementation reduced the O2 cost of submaximal exercise, resulted in greater improvement in incremental (but not severe-intensity) exercise performance, and augmented some muscle metabolic adaptations to training. Nitrate supplementation may facilitate some of the physiological responses to sprint interval training. PMID:27909231

Digestive Organ in the Female Reproductive Tract Borrows Genes from Multiple Organ Systems to Adopt Critical Functions

PubMed Central

Meslin, Camille; Plakke, Melissa S.; Deutsch, Aaron B.; Small, Brandon S.; Morehouse, Nathan I.; Clark, Nathan L.

2015-01-01

Persistent adaptive challenges are often met with the evolution of novel physiological traits. Although there are specific examples of single genes providing new physiological functions, studies on the origin of complex organ functions are lacking. One such derived set of complex functions is found in the Lepidopteran bursa copulatrix, an organ within the female reproductive tract that digests nutrients from the male ejaculate or spermatophore. Here, we characterized bursa physiology and the evolutionary mechanisms by which it was equipped with digestive and absorptive functionality. By studying the transcriptome of the bursa and eight other tissues, we revealed a suite of highly expressed and secreted gene products providing the bursa with a combination of stomach-like traits for mechanical and enzymatic digestion of the male spermatophore. By subsequently placing these bursa genes in an evolutionary framework, we found that the vast majority of their novel digestive functions were co-opted by borrowing genes that continue to be expressed in nonreproductive tissues. However, a number of bursa-specific genes have also arisen, some of which represent unique gene families restricted to Lepidoptera and may provide novel bursa-specific functions. This pattern of promiscuous gene borrowing and relatively infrequent evolution of tissue-specific duplicates stands in contrast to studies of the evolution of novelty via single gene co-option. Our results suggest that the evolution of complex organ-level phenotypes may often be enabled (and subsequently constrained) by changes in tissue specificity that allow expression of existing genes in novel contexts, such as reproduction. The extent to which the selective pressures encountered in these novel roles require resolution via duplication and sub/neofunctionalization is likely to be determined by the need for specialized reproductive functionality. Thus, complex physiological phenotypes such as that found in the bursa offer important opportunities for understanding the relative role of pleiotropy and specialization in adaptive evolution. PMID:25725432

Matching pollution with adaptive changes in mangrove plants by multivariate statistics. A case study, Rhizophora mangle from four neotropical mangroves in Brazil.

PubMed

Souza, Iara da Costa; Morozesk, Mariana; Duarte, Ian Drumond; Bonomo, Marina Marques; Rocha, Lívia Dorsch; Furlan, Larissa Maria; Arrivabene, Hiulana Pereira; Monferrán, Magdalena Victoria; Matsumoto, Silvia Tamie; Milanez, Camilla Rozindo Dias; Wunderlin, Daniel Alberto; Fernandes, Marisa Narciso

2014-08-01

Roots of mangrove trees have an important role in depurating water and sediments by retaining metals that may accumulate in different plant tissues, affecting physiological processes and anatomy. The present study aimed to evaluate adaptive changes in root of Rhizophora mangle in response to different levels of chemical elements (metals/metalloids) in interstitial water and sediments from four neotropical mangroves in Brazil. What sets this study apart from other studies is that we not only investigate adaptive modifications in R. mangle but also changes in environments where this plant grows, evaluating correspondence between physical, chemical and biological issues by a combined set of multivariate statistical methods (pattern recognition). Thus, we looked to match changes in the environment with adaptations in plants. Multivariate statistics highlighted that the lignified periderm and the air gaps are directly related to the environmental contamination. Current results provide new evidences of root anatomical strategies to deal with contaminated environments. Multivariate statistics greatly contributes to extrapolate results from complex data matrixes obtained when analyzing environmental issues, pointing out parameters involved in environmental changes and also evidencing the adaptive response of the exposed biota. Copyright © 2014 Elsevier Ltd. All rights reserved.

Association between endothelial nitric oxide synthase (ENOS) G894T polymorphism and high altitude (HA) adaptation: a meta-analysis.

PubMed

Lu, Hong-xiang; Wang, Yu-xiao; Chen, Yu; Luo, Yong-jun

2015-11-01

Highland natives adapt well to the hypoxic environment at high altitude (HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial ni- tric oxide synthase (ENOS) G894T polymorphism contributed to the physiology and pathophysiology of hu- mans at HA by regulating the production of NO. In this meta-analysis, we evaluate the association between the ENOS G894T polymorphism and HA adaptation through analyzing the published data. We searched all relevant literature about the ENOS G894T polymorphism and HA adaptation in PubMed, Med- line, and Embase before Step 2015. A random-effects model was applied (Revman 5.0), and study quality was assessed in duplicate. Six studies with 634 HA native cases and 621 low-altitude controls were included in this meta-analysis. From the results, we observed that the wild-type allele G was significantly overrepresented in the HA groups (OR = 1.85; 95% Cl, 1.47-2.33; P < 0.0001). In addition, the GG genotype was significantly associated with HA adaptation (OR = 1.99; 95% Cl, 1.54-2.57; P < 0.0001). Our results showed that in 894 G allele carriers, the GG genotype might be a beneficial factor for HA adaptation through enhancing the level of NO. However, more studies were needed to confirm our findings due to the limited sample size.

Adaptive Patterns of Mitogenome Evolution Are Associated with the Loss of Shell Scutes in Turtles.

PubMed

Escalona, Tibisay; Weadick, Cameron J; Antunes, Agostinho

2017-10-01

The mitochondrial genome encodes several protein components of the oxidative phosphorylation (OXPHOS) pathway and is critical for aerobic respiration. These proteins have evolved adaptively in many taxa, but linking molecular-level patterns with higher-level attributes (e.g., morphology, physiology) remains a challenge. Turtles are a promising system for exploring mitochondrial genome evolution as different species face distinct respiratory challenges and employ multiple strategies for ensuring efficient respiration. One prominent adaptation to a highly aquatic lifestyle in turtles is the secondary loss of keratenized shell scutes (i.e., soft-shells), which is associated with enhanced swimming ability and, in some species, cutaneous respiration. We used codon models to examine patterns of selection on mitochondrial protein-coding genes along the three turtle lineages that independently evolved soft-shells. We found strong evidence for positive selection along the branches leading to the pig-nosed turtle (Carettochelys insculpta) and the softshells clade (Trionychidae), but only weak evidence for the leatherback (Dermochelys coriacea) branch. Positively selected sites were found to be particularly prevalent in OXPHOS Complex I proteins, especially subunit ND2, along both positively selected lineages, consistent with convergent adaptive evolution. Structural analysis showed that many of the identified sites are within key regions or near residues involved in proton transport, indicating that positive selection may have precipitated substantial changes in mitochondrial function. Overall, our study provides evidence that physiological challenges associated with adaptation to a highly aquatic lifestyle have shaped the evolution of the turtle mitochondrial genome in a lineage-specific manner. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Mudskipper genomes provide insights into the terrestrial adaptation of amphibious fishes.

PubMed

You, Xinxin; Bian, Chao; Zan, Qijie; Xu, Xun; Liu, Xin; Chen, Jieming; Wang, Jintu; Qiu, Ying; Li, Wujiao; Zhang, Xinhui; Sun, Ying; Chen, Shixi; Hong, Wanshu; Li, Yuxiang; Cheng, Shifeng; Fan, Guangyi; Shi, Chengcheng; Liang, Jie; Tom Tang, Y; Yang, Chengye; Ruan, Zhiqiang; Bai, Jie; Peng, Chao; Mu, Qian; Lu, Jun; Fan, Mingjun; Yang, Shuang; Huang, Zhiyong; Jiang, Xuanting; Fang, Xiaodong; Zhang, Guojie; Zhang, Yong; Polgar, Gianluca; Yu, Hui; Li, Jia; Liu, Zhongjian; Zhang, Guoqiang; Ravi, Vydianathan; Coon, Steven L; Wang, Jian; Yang, Huanming; Venkatesh, Byrappa; Wang, Jun; Shi, Qiong

2014-12-02

Mudskippers are amphibious fishes that have developed morphological and physiological adaptations to match their unique lifestyles. Here we perform whole-genome sequencing of four representative mudskippers to elucidate the molecular mechanisms underlying these adaptations. We discover an expansion of innate immune system genes in the mudskippers that may provide defence against terrestrial pathogens. Several genes of the ammonia excretion pathway in the gills have experienced positive selection, suggesting their important roles in mudskippers' tolerance to environmental ammonia. Some vision-related genes are differentially lost or mutated, illustrating genomic changes associated with aerial vision. Transcriptomic analyses of mudskippers exposed to air highlight regulatory pathways that are up- or down-regulated in response to hypoxia. The present study provides a valuable resource for understanding the molecular mechanisms underlying water-to-land transition of vertebrates.

Cardiovascular adaptations to marathon running : the marathoner's heart.

PubMed

Thompson, Paul D

2007-01-01

Endurance exercise training produces a series of cardiac adaptations including resting bradycardia, first and second degree atrioventricular block, increased intolerance to orthostatic stress, and enlargement of the left ventricular walls and of all cardiac chambers. Cardiac dimensions may be increased beyond the upper limits of normal and some endurance athletes demonstrate mild reductions in estimated left ventricular ejection fraction. Among athletes, such adaptations occur primarily in well trained endurance athletes. Clinicians should be aware of the cardiac changes accompanying endurance training to avoid unnecessary evaluation of physiological changes. On the other hand, the presence of conduction abnormalities or cardiac enlargement in low level or recreational athletes should prompt a search for pathological causes. Many of these findings were presented in the 1977 report on the marathon and have simply been better defined with subsequent studies.

Ambiguous Tilt and Translation Motion Cues in Astronauts After Space Flight (ZAG)

NASA Astrophysics Data System (ADS)

Clement, Guilles; Harm, Deborah; Rupert, Angus; Beaton, Kara; Wood, Scott

2008-06-01

Adaptive changes during space flight in how the brain integrates vestibular cues with visual, proprioceptive, and somatosensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions following transitions between gravity levels. This joint ESA-NASA pre- and post-flight experiment is designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances in astronauts following short-duration space flights. Specifically, this study addresses three questions: (1) What adaptive changes occur in eye movements and motion perception in response to different combinations of tilt and translation motion? (2) Do adaptive changes in tilt-translation responses impair ability to manually control vehicle orientation? (3) Can sensory substitution aids (e.g., tactile) mitigate risks associated with manual control of vehicle orientation?

Insights into the Evolution of Host Association through the Isolation and Characterization of a Novel Human Periodontal Pathobiont, Desulfobulbus oralis.

PubMed

Cross, Karissa L; Chirania, Payal; Xiong, Weili; Beall, Clifford J; Elkins, James G; Giannone, Richard J; Griffen, Ann L; Guss, Adam M; Hettich, Robert L; Joshi, Snehal S; Mokrzan, Elaine M; Martin, Roman K; Zhulin, Igor B; Leys, Eugene J; Podar, Mircea

2018-03-13

The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously uncultured Desulfobulbus oralis , the first human-associated representative of its genus. As mammalian-associated microbes rarely have free-living close relatives, D. oralis provides opportunities to study how bacteria adapt and evolve within a host. This sulfate-reducing deltaproteobacterium has adapted to the human oral subgingival niche by curtailing its physiological repertoire, losing some biosynthetic abilities and metabolic independence, and by dramatically reducing environmental sensing and signaling capabilities. The genes that enable free-living Desulfobulbus to synthesize the potent neurotoxin methylmercury were also lost by D. oralis , a notably positive outcome of host association. However, horizontal gene acquisitions from other members of the microbiota provided novel mechanisms of interaction with the human host, including toxins like leukotoxin and hemolysins. Proteomic and transcriptomic analysis revealed that most of those factors are actively expressed, including in the subgingival environment, and some are secreted. Similar to other known oral pathobionts, D. oralis can trigger a proinflammatory response in oral epithelial cells, suggesting a direct role in the development of periodontal disease. IMPORTANCE Animal-associated microbiota likely assembled as a result of numerous independent colonization events by free-living microbes followed by coevolution with their host and other microbes. Through specific adaptation to various body sites and physiological niches, microbes have a wide range of contributions, from beneficial to disease causing. Desulfobulbus oralis provides insights into genomic and physiological transformations associated with transition from an open environment to a host-dependent lifestyle and the emergence of pathogenicity. Through a multifaceted mechanism triggering a proinflammatory response, D. oralis is a novel periodontal pathobiont. Even though culture-independent approaches can provide insights into the potential role of the human microbiome "dark matter," cultivation and experimental characterization remain important to studying the roles of individual organisms in health and disease.

'Multimorbidity' as the manifestation of network disturbances.

PubMed

Sturmberg, Joachim P; Bennett, Jeanette M; Martin, Carmel M; Picard, Martin

2017-02-01

We argue that 'multimorbidity' is the manifestation of interconnected physiological network processes within an individual in his or her socio-cultural environment. Networks include genomic, metabolomic, proteomic, neuroendocrine, immune and mitochondrial bioenergetic elements, as well as social, environmental and health care networks. Stress systems and other physiological mechanisms create feedback loops that integrate and regulate internal networks within the individual. Minor (e.g. daily hassles) and major (e.g. trauma) stressful life experiences perturb internal and social networks resulting in physiological instability with changes ranging from improved resilience to unhealthy adaptation and 'clinical disease'. Understanding 'multimorbidity' as a complex adaptive systems response to biobehavioural and socio-environmental networks is essential. Thus, designing integrative care delivery approaches that more adequately address the underlying disease processes as the manifestation of a state of physiological dysregulation is essential. This framework can shape care delivery approaches to meet the individual's care needs in the context of his or her underlying illness experience. It recognizes 'multimorbidity' and its symptoms as the end product of complex physiological processes, namely, stress activation and mitochondrial energetics, and suggests new opportunities for treatment and prevention. The future of 'multimorbidity' management might become much more discerning by combining the balancing of physiological dysregulation with targeted personalized biotechnology interventions such as small molecule therapeutics targeting specific cellular components of the stress response, with community-embedded interventions that involve addressing psycho-socio-cultural impediments that would aim to strengthen personal/social resilience and enhance social capital. © 2016 John Wiley & Sons, Ltd.

A new way of thinking about complications of prematurity.

PubMed

Moore, Tiffany A; Berger, Ann M; Wilson, Margaret E

2014-01-01

The morbidity and mortality of preterm infants are impacted by their ability to maintain physiologic homeostasis using metabolic, endocrine, and immunologic mechanisms independent of the mother's placenta. Exploring McEwen's allostatic load model in preterm infants provides a new way to understand the altered physiologic processes associated with frequently occurring complications of prematurity such as bronchopulmonary dysplasia, intraventricular hemorrhage, necrotizing enterocolitis, and retinopathy of prematurity. The purpose of this article is to present a new model to enhance understanding of the altered physiologic processes associated with complications of prematurity. The model of allostatic load and complications of prematurity was derived to explore the relationship between general stress of prematurity and complications of prematurity. The proposed model uses the concepts of general stress of prematurity, allostasis, physiologic response patterns (adaptive-maladaptive), allostatic load, and complications of prematurity. These concepts are defined and theoretical relationships in the proposed model are interpreted using the four maladaptive response patterns of repeated hits, lack of adaptation, prolonged response, and inadequate response. Empirical evidence for cortisol, inflammation, and oxidative stress responses are used to support the theoretical relationships. The proposed model provides a new way of thinking about physiologic dysregulation in preterm infants. The ability to describe and understand complex physiologic mechanisms involved in complications of prematurity is essential for research. Advancing the knowledge of complications of prematurity will advance clinical practice and research and lead to testing of interventions to reduce negative outcomes in preterm infants.

Physiological differences between cycling and running: lessons from triathletes.

PubMed

Millet, Gregoire P; Vleck, V E; Bentley, D J

2009-01-01

The purpose of this review was to provide a synopsis of the literature concerning the physiological differences between cycling and running. By comparing physiological variables such as maximal oxygen consumption (V O(2max)), anaerobic threshold (AT), heart rate, economy or delta efficiency measured in cycling and running in triathletes, runners or cyclists, this review aims to identify the effects of exercise modality on the underlying mechanisms (ventilatory responses, blood flow, muscle oxidative capacity, peripheral innervation and neuromuscular fatigue) of adaptation. The majority of studies indicate that runners achieve a higher V O(2max) on treadmill whereas cyclists can achieve a V O(2max) value in cycle ergometry similar to that in treadmill running. Hence, V O(2max) is specific to the exercise modality. In addition, the muscles adapt specifically to a given exercise task over a period of time, resulting in an improvement in submaximal physiological variables such as the ventilatory threshold, in some cases without a change in V O(2max). However, this effect is probably larger in cycling than in running. At the same time, skill influencing motor unit recruitment patterns is an important influence on the anaerobic threshold in cycling. Furthermore, it is likely that there is more physiological training transfer from running to cycling than vice versa. In triathletes, there is generally no difference in V O(2max) measured in cycle ergometry and treadmill running. The data concerning the anaerobic threshold in cycling and running in triathletes are conflicting. This is likely to be due to a combination of actual training load and prior training history in each discipline. The mechanisms surrounding the differences in the AT together with V O(2max) in cycling and running are not largely understood but are probably due to the relative adaptation of cardiac output influencing V O(2max) and also the recruitment of muscle mass in combination with the oxidative capacity of this mass influencing the AT. Several other physiological differences between cycling and running are addressed: heart rate is different between the two activities both for maximal and submaximal intensities. The delta efficiency is higher in running. Ventilation is more impaired in cycling than in running. It has also been shown that pedalling cadence affects the metabolic responses during cycling but also during a subsequent running bout. However, the optimal cadence is still debated. Central fatigue and decrease in maximal strength are more important after prolonged exercise in running than in cycling.

Multivariable adaptive closed-loop control of an artificial pancreas without meal and activity announcement.

PubMed

Turksoy, Kamuran; Bayrak, Elif Seyma; Quinn, Lauretta; Littlejohn, Elizabeth; Cinar, Ali

2013-05-01

Accurate closed-loop control is essential for developing artificial pancreas (AP) systems that adjust insulin infusion rates from insulin pumps. Glucose concentration information from continuous glucose monitoring (CGM) systems is the most important information for the control system. Additional physiological measurements can provide valuable information that can enhance the accuracy of the control system. Proportional-integral-derivative control and model predictive control have been popular in AP development. Their implementations to date rely on meal announcements (e.g., bolus insulin dose based on insulin:carbohydrate ratios) by the user. Adaptive control techniques provide a powerful alternative that do not necessitate any meal or activity announcements. Adaptive control systems based on the generalized predictive control framework are developed by extending the recursive modeling techniques. Physiological signals such as energy expenditure and galvanic skin response are used along with glucose measurements to generate a multiple-input-single-output model for predicting future glucose concentrations used by the controller. Insulin-on-board (IOB) is also estimated and used in control decisions. The controllers were tested with clinical studies that include seven cases with three different patients with type 1 diabetes for 32 or 60 h without any meal or activity announcements. The adaptive control system kept glucose concentration in the normal preprandial and postprandial range (70-180 mg/dL) without any meal or activity announcements during the test period. After IOB estimation was added to the control system, mild hypoglycemic episodes were observed only in one of the four experiments. This was reflected in a plasma glucose value of 56 mg/dL (YSI 2300 STAT; Yellow Springs Instrument, Yellow Springs, OH) and a CGM value of 63 mg/dL). Regulation of blood glucose concentration with an AP using adaptive control techniques was successful in clinical studies, even without any meal and physical activity announcement.

Causes and consequences of reduced blood volume in space flight - A multi-discipline modeling study

NASA Technical Reports Server (NTRS)

Leonard, J. I.

1983-01-01

A group of mathematical models of various physiological systems have been developed and applied to studying problems associated with adaptation to weightlessness. One biomedical issue which could be addressed by at least three of these models from varying perspectives was the reduction in blood volume that universally occurs in astronauts. Accordingly, models of fluid-electrolyte, erythropoiesis, and cardiovascular regulation were employed to study the causes and consequences of blood volume loss during space flight. This analysis confirms the notion that alterations of blood volume are central to an understanding of adaptation to prolonged space flight. More importantly, the modeling studies resulted in specific hypotheses accounting for plasma volume and red cell mass losses and testable predictions concerning the behavior of the circulatory system.

Nutrition in space

NASA Technical Reports Server (NTRS)

Smith, S. M.; Davis-Street, J.; Rice, B. L.; Lane, H. W.

1997-01-01

The authors review studies conducted to define nutritional requirements for astronauts during space flight and to assess nutrition before, during, and after space flight. Topics include space food systems, research and limitations on spacecraft, physiological adaptation to weightlessness, energy requirements, dietary intake during space flight, bone demineralization, gastrointestinal function, blood volume, and nutrition requirements for space flight. Benefits of space-related nutrition research are highlighted.

A Model System for Studying the Transcriptomic and Physiological Changes Associated with Mammalian Host-Adaptation by Leptospira interrogans Serovar Copenhageni

PubMed Central

Caimano, Melissa J.; Sivasankaran, Sathesh K.; Allard, Anna; Hurley, Daniel; Hokamp, Karsten; Grassmann, André A.; Hinton, Jay C. D.; Nally, Jarlath E.

2014-01-01

Leptospirosis, an emerging zoonotic disease with worldwide distribution, is caused by spirochetes belonging to the genus Leptospira. More than 500,000 cases of severe leptospirosis are reported annually, with >10% of these being fatal. Leptospires can survive for weeks in suitably moist conditions before encountering a new host. Reservoir hosts, typically rodents, exhibit little to no signs of disease but shed large numbers of organisms in their urine. Transmission occurs when mucosal surfaces or abraded skin come into contact with infected urine or urine-contaminated water or soil. In humans, leptospires can cause a variety of clinical manifestations, ranging from asymptomatic or mild fever to severe icteric (Weil's) disease and pulmonary haemorrhage. Currently, little is known about how Leptospira persist within a reservoir host. Prior in vitro studies have suggested that leptospires alter their transcriptomic and proteomic profiles in response to environmental signals encountered during mammalian infection. However, no study has examined gene expression by leptospires within a mammalian host-adapted state. To obtain a more faithful representation of how leptospires respond to host-derived signals, we used RNA-Seq to compare the transcriptome of L. interrogans cultivated within dialysis membrane chambers (DMCs) implanted into the peritoneal cavities of rats with that of organisms grown in vitro. In addition to determining the relative expression levels of “core” housekeeping genes under both growth conditions, we identified 166 genes that are differentially-expressed by L. interrogans in vivo. Our analyses highlight physiological aspects of host adaptation by leptospires relating to heme uptake and utilization. We also identified 11 novel non-coding transcripts that are candidate small regulatory RNAs. The DMC model provides a facile system for studying the transcriptional and antigenic changes associated with mammalian host-adaption, selection of targets for mutagenesis, and the identification of previously unrecognized virulence determinants. PMID:24626166

Intraspecific variation in stomatal traits, leaf traits and physiology reflects adaptation along aridity gradients in a South African shrub

PubMed Central

Carlson, Jane E.; Adams, Christopher A.; Holsinger, Kent E.

2016-01-01

Background and Aims Trait–environment relationships are commonly interpreted as evidence for local adaptation in plants. However, even when selection analyses support this interpretation, the mechanisms underlying differential benefits are often unknown. This study addresses this gap in knowledge using the broadly distributed South African shrub Protea repens. Specifically, the study examines whether broad-scale patterns of trait variation are consistent with spatial differences in selection and ecophysiology in the wild. Methods In a common garden study of plants sourced from 19 populations, associations were measured between five morphological traits and three axes describing source climates. Trait–trait and trait–environment associations were analysed in a multi-response model. Within two focal populations in the wild, selection and path analyses were used to test associations between traits, fecundity and physiological performance. Key Results Across 19 populations in a common garden, stomatal density increased with the source population’s mean annual temperature and decreased with its average amount of rainfall in midsummer. Concordantly, selection analysis in two natural populations revealed positive selection on stomatal density at the hotter, drier site, while failing to detect selection at the cooler, moister site. Dry-site plants with high stomatal density also had higher stomatal conductances, cooler leaf temperatures and higher light-saturated photosynthetic rates than those with low stomatal density, but no such relationships were present among wet-site plants. Leaf area, stomatal pore index and specific leaf area in the garden also co-varied with climate, but within-population differences were not associated with fitness in either wild population. Conclusions The parallel patterns of broad-scale variation, differences in selection and differences in trait–ecophysiology relationships suggest a mechanism for adaptive differentiation in stomatal density. Densely packed stomata may improve performance by increasing transpiration and cooling, but predominately in drier, hotter climates. This study uniquely shows context-dependent benefits of stomatal density – a trait rarely linked to local adaptation in plants. PMID:26424782

Adaptive Appraisals of Anxiety Moderate the Association between Cortisol Reactivity and Performance in Salary Negotiations

PubMed Central

Fridman, Ilona; Mor, Shira; Morris, Michael W.; Crum, Alia J.

2016-01-01

Prior research suggests that stress can be harmful in high-stakes contexts such as negotiations. However, few studies actually measure stress physiologically during negotiations, nor do studies offer interventions to combat the potential negative effects of heightened physiological responses in negotiation contexts. In the current research, we offer evidence that the negative effects of cortisol increases on negotiation performance can be reduced through a reappraisal of anxiety manipulation. We experimentally induced adaptive appraisals by randomly assigning 97 male and female participants to receive either instructions to appraise their anxiety as beneficial to the negotiation or no specific instructions on how to appraise the situation. We also measured participants’ cortisol responses prior to and following the negotiation. Results revealed that cortisol increases were positively related to negotiation performance for participants who were told to view anxiety as beneficial, and not detrimental, for negotiation performance (appraisal condition). In contrast, cortisol increases were negatively related to negotiation performance for participants given no instructions on appraising their anxiety (control condition). These findings offer a means through which to combat the potentially deleterious effects of heightened cortisol reactivity on negotiation outcomes. PMID:27992484

Intraspecific variation in social organization by genetic variation, developmental plasticity, social flexibility or entirely extrinsic factors.

PubMed

Schradin, Carsten

2013-05-19

Previously, it was widely believed that each species has a specific social organization, but we know now that many species show intraspecific variation in their social organization. Four different processes can lead to intraspecific variation in social organization: (i) genetic variation between individuals owing to local adaptation (between populations) or evolutionarily stable strategies within populations; (ii) developmental plasticity evolved in long-term (more than one generation) unpredictable and short-term (one generation) predictable environments, which is mediated by organizational physiological effects during early ontogeny; (iii) social flexibility evolved in highly unpredictable environments, which is mediated by activational physiological effects in adults; (iv) entirely extrinsic factors such as the death of a dominant breeder. Variation in social behaviour occurs between individuals in the case of genetic variation and developmental plasticity, but within individuals in the case of social flexibility. It is important to study intraspecific variation in social organization to understand the social systems of species because it reveals the mechanisms by which species can adapt to changing environments, offers a useful tool to study the ultimate and proximate causes of sociality, and is an interesting phenomenon by itself that needs scientific explanation.

Adaptive Appraisals of Anxiety Moderate the Association between Cortisol Reactivity and Performance in Salary Negotiations.

PubMed

Akinola, Modupe; Fridman, Ilona; Mor, Shira; Morris, Michael W; Crum, Alia J

2016-01-01

Prior research suggests that stress can be harmful in high-stakes contexts such as negotiations. However, few studies actually measure stress physiologically during negotiations, nor do studies offer interventions to combat the potential negative effects of heightened physiological responses in negotiation contexts. In the current research, we offer evidence that the negative effects of cortisol increases on negotiation performance can be reduced through a reappraisal of anxiety manipulation. We experimentally induced adaptive appraisals by randomly assigning 97 male and female participants to receive either instructions to appraise their anxiety as beneficial to the negotiation or no specific instructions on how to appraise the situation. We also measured participants' cortisol responses prior to and following the negotiation. Results revealed that cortisol increases were positively related to negotiation performance for participants who were told to view anxiety as beneficial, and not detrimental, for negotiation performance (appraisal condition). In contrast, cortisol increases were negatively related to negotiation performance for participants given no instructions on appraising their anxiety (control condition). These findings offer a means through which to combat the potentially deleterious effects of heightened cortisol reactivity on negotiation outcomes.

A NAP-Family Histone Chaperone Functions in Abiotic Stress Response and Adaptation1[OPEN

PubMed Central

Pareek, Ashwani; Singla-Pareek, Sneh Lata

2016-01-01

Modulation of gene expression is one of the most significant molecular mechanisms of abiotic stress response in plants. Via altering DNA accessibility, histone chaperones affect the transcriptional competence of genomic loci. However, in contrast to other factors affecting chromatin dynamics, the role of plant histone chaperones in abiotic stress response and adaptation remains elusive. Here, we studied the physiological function of a stress-responsive putative rice (Oryza sativa) histone chaperone of the NAP superfamily: OsNAPL6. We show that OsNAPL6 is a nuclear-localized H3/H4 histone chaperone capable of assembling a nucleosome-like structure. Utilizing overexpression and knockdown approaches, we found a positive correlation between OsNAPL6 expression levels and adaptation to multiple abiotic stresses. Results of comparative transcriptome profiling and promoter-recruitment studies indicate that OsNAPL6 functions during stress response via modulation of expression of various genes involved in diverse functions. For instance, we show that OsNAPL6 is recruited to OsRad51 promoter, activating its expression and leading to more efficient DNA repair and abrogation of programmed cell death under salinity and genotoxic stress conditions. These results suggest that the histone chaperone OsNAPL6 may serve a regulatory role in abiotic stress physiology possibly via modulating nucleosome dynamics at various stress-associated genomic loci. Taken together, our findings establish a hitherto unknown link between histone chaperones and abiotic stress response in plants. PMID:27342307

Adjusting to climate: acclimation, adaptation, and developmental plasticity in physiological traits of a tropical rainforest lizard.

PubMed

Llewelyn, John; Macdonald, Stewart L; Moritz, Craig; Martins, Felipe; Hatcher, Amberlee; Phillips, Ben L

2018-01-09

The impact of climate change may be felt most keenly by tropical ectotherms. In these taxa, it is argued, thermal specialisation means a given shift in temperature will have a larger effect on fitness. For species with limited dispersal ability, the impact of climate change depends on the capacity for their climate-relevant traits to shift. Such shifts can occur through genetic adaptation, various forms of plasticity, or a combination of these processes. Here we assess the extent and causes of shifts in seven physiological traits in a tropical lizard, the rainforest sunskink (Lampropholis coggeri). Two populations were sampled that differ from each other in both climate and physiological traits. We compared trait values in each animal soon after field collection versus following acclimation to laboratory conditions. We also compared trait values between populations in: (1) recently field-collected animals, (2) the same animals following laboratory acclimation, and (3) the laboratory-reared offspring of these animals. Our results reveal high trait lability, driven primarily by acclimation and local adaptation. By contrast, developmental plasticity, resulting from incubation temperature, had little-to-no effect on most traits. These results suggest that, while specialised, tropical ectotherms may be capable of rapid shifts in climate-relevant traits. This article is protected by copyright. All rights reserved.

Genotypic variation in traits linked to climate and aboveground productivity in a widespread C₄ grass: evidence for a functional trait syndrome.

PubMed

Aspinwall, Michael J; Lowry, David B; Taylor, Samuel H; Juenger, Thomas E; Hawkes, Christine V; Johnson, Mari-Vaughn V; Kiniry, James R; Fay, Philip A

2013-09-01

Examining intraspecific variation in growth and function in relation to climate may provide insight into physiological evolution and adaptation, and is important for predicting species responses to climate change. Under common garden conditions, we grew nine genotypes of the C₄ species Panicum virgatum originating from different temperature and precipitation environments. We hypothesized that genotype productivity, morphology and physiological traits would be correlated with climate of origin, and a suite of adaptive traits would show high broad-sense heritability (H(2)). Genotype productivity and flowering time increased and decreased, respectively, with home-climate temperature, and home-climate temperature was correlated with genotypic differences in a syndrome of morphological and physiological traits. Genotype leaf and tiller size, leaf lamina thickness, leaf mass per area (LMA) and C : N ratios increased with home-climate temperature, whereas leaf nitrogen per unit mass (Nm ) and chlorophyll (Chl) decreased with home-climate temperature. Trait variation was largely explained by genotypic differences (H(2) = 0.33-0.85). Our results provide new insight into the role of climate in driving functional trait coordination, local adaptation and genetic divergence within species. These results emphasize the importance of considering intraspecific variation in future climate change scenarios. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

The Role of Physiological Arousal in Time Perception: Psychophysiological Evidence from an Emotion Regulation Paradigm

ERIC Educational Resources Information Center

Mella, N.; Conty, L.; Pouthas, V.

2011-01-01

Time perception, crucial for adaptive behavior, has been shown to be altered by emotion. An arousal-dependent mechanism is proposed to account for such an effect. Yet, physiological measure of arousal related with emotional timing is still lacking. We addressed this question using skin conductance response (SCR) in an emotion regulation paradigm.…

The infectious hypoxia: occurrence and causes during Shigella infection.

PubMed

Arena, Ellen T; Tinevez, Jean-Yves; Nigro, Giulia; Sansonetti, Philippe J; Marteyn, Benoit S

2017-03-01

Hypoxia is defined as a tissue oxygenation status below physiological needs. During Shigella infection, an infectious hypoxia is induced within foci of infection. In this review, we discuss how Shigella physiology and virulence are modulated and how the main recruited immune cells, the neutrophils, adapt to this environment. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

You Get What You Get and You Don't Throw a Fit!: Emotion Socialization and Child Physiology Jointly Predict Early Prosocial Development

ERIC Educational Resources Information Center

Scrimgeour, Meghan B.; Davis, Elizabeth L.; Buss, Kristin A.

2016-01-01

Prosocial behavior in early childhood is a precursor to later adaptive social functioning. This investigation leveraged mother-reported, physiological, and observational data to examine children's prosocial development from age 2 to age 4 (N = 125). Maternal emotion socialization (ES) strategies and children's parasympathetic regulation have each…

Hypoxia decreases creatine uptake in cardiomyocytes, while creatine supplementation enhances HIF activation.

PubMed

Santacruz, Lucia; Arciniegas, Antonio Jose Luis; Darrabie, Marcus; Mantilla, Jose G; Baron, Rebecca M; Bowles, Dawn E; Mishra, Rajashree; Jacobs, Danny O

2017-08-01

Creatine (Cr), phosphocreatine (PCr), and creatine kinases (CK) comprise an energy shuttle linking ATP production in mitochondria with cellular consumption sites. Myocytes cannot synthesize Cr: these cells depend on uptake across the cell membrane by a specialized creatine transporter (CrT) to maintain intracellular Cr levels. Hypoxia interferes with energy metabolism, including the activity of the creatine energy shuttle, and therefore affects intracellular ATP and PCr levels. Here, we report that exposing cultured cardiomyocytes to low oxygen levels rapidly diminishes Cr transport by decreasing V max and K m Pharmacological activation of AMP-activated kinase (AMPK) abrogated the reduction in Cr transport caused by hypoxia. Cr supplementation increases ATP and PCr content in cardiomyocytes subjected to hypoxia, while also significantly augmenting the cellular adaptive response to hypoxia mediated by HIF-1 activation. Our results indicate that: (1) hypoxia reduces Cr transport in cardiomyocytes in culture, (2) the cytoprotective effects of Cr supplementation are related to enhanced adaptive physiological responses to hypoxia mediated by HIF-1, and (3) Cr supplementation increases the cellular ATP and PCr content in RNCMs exposed to hypoxia. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Metabolic analysis of adaptive evolution for in silico-designed lactate-producing strains.

PubMed

Hua, Qiang; Joyce, Andrew R; Fong, Stephen S; Palsson, Bernhard Ø

2006-12-05

Experimental evolution is now frequently applied to many biological systems to achieve desired objectives. To obtain optimized performance for metabolite production, a successful strategy has been recently developed that couples metabolic engineering techniques with laboratory evolution of microorganisms. Previously, we reported the growth characteristics of three lactate-producing, adaptively evolved Escherichia coli mutant strains designed by the OptKnock computational algorithm. Here, we describe the use of (13)C-labeled experiments and mass distribution measurements to study the evolutionary effects on the fluxome of these differently designed strains. Metabolic flux ratios and intracellular flux distributions as well as physiological data were used to elucidate metabolic responses over the course of adaptive evolution and metabolic differences among strains. The study of 3 unevolved and 12 evolved engineered strains as well as a wild-type strain suggests that evolution resulted in remarkable improvements in both substrate utilization rate and the proportion of glycolytic flux to total glucose utilization flux. Among three strain designs, the most significant increases in the fraction of glucose catabolized through glycolysis (>50%) and the glycolytic fluxes (>twofold) were observed in phosphotransacetylase and phosphofructokinase 1 (PFK1) double deletion (pta- pfkA) strains, which were likely attributed to the dramatic evolutionary increase in gene expression and catalytic activity of the minor PFK encoded by pfkB. These fluxomic studies also revealed the important role of acetate synthetic pathway in anaerobic lactate production. Moreover, flux analysis suggested that independent of genetic background, optimal relative flux distributions in cells could be achieved faster than physiological parameters such as nutrient utilization rate. (c) 2006 Wiley Periodicals, Inc.

Ageing and cardiorespiratory response to hypoxia.

PubMed

Lhuissier, François J; Canouï-Poitrine, Florence; Richalet, Jean-Paul

2012-11-01

The risk of severe altitude-induced diseases is related to ventilatory and cardiac responses to hypoxia and is dependent on sex, age and exercise training status. However, it remains unclear how ageing modifies these physiological adaptations to hypoxia. We assessed the physiological responses to hypoxia with ageing through a cross-sectional 20 year study including 4675 subjects (2789 men, 1886 women; 14-85 years old) and a longitudinal study including 30 subjects explored at a mean 10.4 year interval. The influence of sex, training status and menopause was evaluated. The hypoxia-induced desaturation and the ventilatory and cardiac responses to hypoxia at rest and exercise were measured. In men, ventilatory response to hypoxia increased (P < 0.002), while desaturation was less pronounced (P < 0.001) with ageing. Cardiac response to hypoxia was blunted with ageing in both sexes (P < 0.001). Similar results were found in the longitudinal study, with a decrease in cardiac and an increase in ventilatory response to hypoxia with ageing. These adaptive responses were less pronounced or absent in post-menopausal women (P < 0.01). At exercise, desaturation was greater in trained subjects but cardiac and ventilatory responses to hypoxia were preserved by training, especially in elderly people. In conclusion, respiratory response to hypoxia and blood oxygenation improve with ageing in men while cardiac response is blunted with ageing in both sexes. Training aggravates desaturation at exercise in hypoxia, improves the ventilatory response and limits the ageing-induced blunting of cardiac response to hypoxia. Training limits the negative effects of menopause in cardiorespiratory adaptations to hypoxia.

Metabolic heat production and thermal conductance are mass-independent adaptations to thermal environment in birds and mammals.

PubMed

Fristoe, Trevor S; Burger, Joseph R; Balk, Meghan A; Khaliq, Imran; Hof, Christian; Brown, James H

2015-12-29

The extent to which different kinds of organisms have adapted to environmental temperature regimes is central to understanding how they respond to climate change. The Scholander-Irving (S-I) model of heat transfer lays the foundation for explaining how endothermic birds and mammals maintain their high, relatively constant body temperatures in the face of wide variation in environmental temperature. The S-I model shows how body temperature is regulated by balancing the rates of heat production and heat loss. Both rates scale with body size, suggesting that larger animals should be better adapted to cold environments than smaller animals, and vice versa. However, the global distributions of ∼9,000 species of terrestrial birds and mammals show that the entire range of body sizes occurs in nearly all climatic regimes. Using physiological and environmental temperature data for 211 bird and 178 mammal species, we test for mass-independent adaptive changes in two key parameters of the S-I model: basal metabolic rate (BMR) and thermal conductance. We derive an axis of thermal adaptation that is independent of body size, extends the S-I model, and highlights interactions among physiological and morphological traits that allow endotherms to persist in a wide range of temperatures. Our macrophysiological and macroecological analyses support our predictions that shifts in BMR and thermal conductance confer important adaptations to environmental temperature in both birds and mammals.

Establishing common course objectives for undergraduate exercise physiology.

PubMed

Simonson, Shawn R

2015-12-01

Undergraduate exercise physiology is a ubiquitous course in undergraduate kinesiology/exercise science programs with a broad scope and depth of topics. It is valuable to explore what is taught within this course. The purpose of the present study was to facilitate an understanding of what instructors teach in undergraduate exercise physiology, how it compares with various guidelines, and to continue the conversation regarding what should be taught. A survey was created using course outcomes from the American Society of Exercise Physiologists, National Association for Sport and Physical Education, Ivy's 2007 Quest article, the National Athletic Training Association, the National Council for Accreditation of Teacher Education, and 36 undergraduate exercise physiology course syllabi. The 134-item survey was disseminated to individuals who use exercise physiology: university faculty members, clinical exercise physiologists, researchers, and other practitioners on various exercise physiology lists; 2,009 surveys were sent, and 322 surveys were completed (16% rate of return). There was a high degree of agreement about a lot of important content in undergraduate exercise physiology. Instructors of exercise physiology should focus their curriculum on regulation and homeostasis (including adaptation, fatigue, and recovery), aerobic systems, bioenergetics, muscle physiology, and fitness principles. In addition, attention should be paid to performance and technical skills. In conclusion, it is up to exercise physiologists to ensure quality of knowledge and practice. Doing so will improve the uniformity and quality of practitioners within the various kinesiology/exercise science fields and increase the value of a Kinesiology/Exercise Science degree and set it apart from other healthcare providers and fitness professionals. Copyright © 2015 The American Physiological Society.

Estimating the capability of microalgae to physiological acclimatization and genetic adaptation to petroleum and diesel oil contamination.

PubMed

Romero-Lopez, Julia; Lopez-Rodas, Victoria; Costas, Eduardo

2012-11-15

There is increasing scientific interest in how phytoplankton reacts to petroleum contamination, since crude oil and its derivatives are generating extensive contamination of aquatic environments. However, toxic effects of short-term petroleum exposure are more widely known than the adaptation of phytoplankton to long-term petroleum exposure. An analysis of short-term and long-term effects of petroleum exposure was done using experimental populations of freshwater (Scenedesmus intermedius and Microcystis aeruginosa) and marine (Dunaliella tertiolecta) microalgae isolated from pristine sites without crude oil product contamination. These strains were exposed to increased levels of petroleum and diesel oil. Short-term exposure to petroleum or diesel oil revealed a rapid inhibition of photosynthetic performance and cell proliferation in freshwater and marine phytoplankton species. A broad degree of inter-specific variation in lethal contamination level was observed. When different strains were exposed to petroleum or diesel oil over the long-term, the cultures showed massive destruction of the sensitive cells. Nonetheless, after further incubation, some cultures were able to grow again due to cells that were resistant to the toxins. By means of a fluctuation analysis, discrimination between cells that had become resistant due to physiological acclimatization and resistant cells arising from rare spontaneous mutations was accomplished. In addition, an analysis was done as to the maximum capacity of adaptation to a gradual contamination process. An experimental ratchet protocol was used, which maintains a strong selection pressure in a temporal scale up to several months over very large experimental populations of microalgae. Microalgae are able to survive to petroleum contamination as a result of physiological acclimatization without genetic changes. However, when petroleum concentration exceeds the physiological limits, survival depends exclusively on the occurrence on mutations that confer resistance and subsequent selection of these mutants. Finally, it is certain that further mutations and selection will ultimately determine adaptation of microalgae to the environmental forcing. Copyright © 2012 Elsevier B.V. All rights reserved.

Modeling gravity-dependent plasticity of the angular vestibuloocular reflex with a physiologically based neural network.

PubMed

Xiang, Yongqing; Yakushin, Sergei B; Cohen, Bernard; Raphan, Theodore

2006-12-01

A neural network model was developed to explain the gravity-dependent properties of gain adaptation of the angular vestibuloocular reflex (aVOR). Gain changes are maximal at the head orientation where the gain is adapted and decrease as the head is tilted away from that position and can be described by the sum of gravity-independent and gravity-dependent components. The adaptation process was modeled by modifying the weights and bias values of a three-dimensional physiologically based neural network of canal-otolith-convergent neurons that drive the aVOR. Model parameters were trained using experimental vertical aVOR gain values. The learning rule aimed to reduce the error between eye velocities obtained from experimental gain values and model output in the position of adaptation. Although the model was trained only at specific head positions, the model predicted the experimental data at all head positions in three dimensions. Altering the relative learning rates of the weights and bias improved the model-data fits. Model predictions in three dimensions compared favorably with those of a double-sinusoid function, which is a fit that minimized the mean square error at every head position and served as the standard by which we compared the model predictions. The model supports the hypothesis that gravity-dependent adaptation of the aVOR is realized in three dimensions by a direct otolith input to canal-otolith neurons, whose canal sensitivities are adapted by the visual-vestibular mismatch. The adaptation is tuned by how the weights from otolith input to the canal-otolith-convergent neurons are adapted for a given head orientation.

Trial-to-trial adaptation in control of arm reaching and standing posture.

PubMed

Pienciak-Siewert, Alison; Horan, Dylan P; Ahmed, Alaa A

2016-12-01

Classical theories of motor learning hypothesize that adaptation is driven by sensorimotor error; this is supported by studies of arm and eye movements that have shown that trial-to-trial adaptation increases with error. Studies of postural control have shown that anticipatory postural adjustments increase with the magnitude of a perturbation. However, differences in adaptation have been observed between the two modalities, possibly due to either the inherent instability or sensory uncertainty in standing posture. Therefore, we hypothesized that trial-to-trial adaptation in posture should be driven by error, similar to what is observed in arm reaching, but the nature of the relationship between error and adaptation may differ. Here we investigated trial-to-trial adaptation of arm reaching and postural control concurrently; subjects made reaching movements in a novel dynamic environment of varying strengths, while standing and holding the handle of a force-generating robotic arm. We found that error and adaptation increased with perturbation strength in both arm and posture. Furthermore, in both modalities, adaptation showed a significant correlation with error magnitude. Our results indicate that adaptation scales proportionally with error in the arm and near proportionally in posture. In posture only, adaptation was not sensitive to small error sizes, which were similar in size to errors experienced in unperturbed baseline movements due to inherent variability. This finding may be explained as an effect of uncertainty about the source of small errors. Our findings suggest that in rehabilitation, postural error size should be considered relative to the magnitude of inherent movement variability. Copyright © 2016 the American Physiological Society.

Team-Centered Perspective for Adaptive Automation Design

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III

2003-01-01

Automation represents a very active area of human factors research. The journal, Human Factors, published a special issue on automation in 1985. Since then, hundreds of scientific studies have been published examining the nature of automation and its interaction with human performance. However, despite a dramatic increase in research investigating human factors issues in aviation automation, there remain areas that need further exploration. This NASA Technical Memorandum describes a new area of automation design and research, called adaptive automation. It discusses the concepts and outlines the human factors issues associated with the new method of adaptive function allocation. The primary focus is on human-centered design, and specifically on ensuring that adaptive automation is from a team-centered perspective. The document shows that adaptive automation has many human factors issues common to traditional automation design. Much like the introduction of other new technologies and paradigm shifts, adaptive automation presents an opportunity to remediate current problems but poses new ones for human-automation interaction in aerospace operations. The review here is intended to communicate the philosophical perspective and direction of adaptive automation research conducted under the Aerospace Operations Systems (AOS), Physiological and Psychological Stressors and Factors (PPSF) project.

A stochastic differential equation model of diurnal cortisol patterns

NASA Technical Reports Server (NTRS)

Brown, E. N.; Meehan, P. M.; Dempster, A. P.

2001-01-01

Circadian modulation of episodic bursts is recognized as the normal physiological pattern of diurnal variation in plasma cortisol levels. The primary physiological factors underlying these diurnal patterns are the ultradian timing of secretory events, circadian modulation of the amplitude of secretory events, infusion of the hormone from the adrenal gland into the plasma, and clearance of the hormone from the plasma by the liver. Each measured plasma cortisol level has an error arising from the cortisol immunoassay. We demonstrate that all of these three physiological principles can be succinctly summarized in a single stochastic differential equation plus measurement error model and show that physiologically consistent ranges of the model parameters can be determined from published reports. We summarize the model parameters in terms of the multivariate Gaussian probability density and establish the plausibility of the model with a series of simulation studies. Our framework makes possible a sensitivity analysis in which all model parameters are allowed to vary simultaneously. The model offers an approach for simultaneously representing cortisol's ultradian, circadian, and kinetic properties. Our modeling paradigm provides a framework for simulation studies and data analysis that should be readily adaptable to the analysis of other endocrine hormone systems.

Animal research in microgravity and flight environment: lessons from the past for the future.

PubMed

Demaria-Pesce, V H

1995-01-01

The use of animals, and more particularly the use of non-human primates, takes on importance when studying the physiological responses involved in the adaptation to changes in gravitational loading. The "Rhesus project", now canceled, was a joint program between CNES and NASA designed to carry out simultaneous experiments of various physiological disciplines using the Rhesus monkey as a human surrogate. The choice of this species was supported by several strong arguments such as the possibility of studying several physiological systems without over-instrumenting, as well as the morphological and phylogenetical closeness with man. Within this framework, building the inflight animal facilities necessary to achieve the ambitious scientific program that was established, required state of art design and technology. Spacelab flight simulations were conducted with the goal both to obtain baseline data and to evaluate the impact of the cabin environment on the circadian timekeeping system which is involved in the regulation of almost all physiological functions and behavior. Even if this project would never fly, the results from these experiments have been a source of thoughts and lessons for the future animal research in microgravity.

Why tropical forest lizards are vulnerable to climate warming

PubMed Central

Huey, Raymond B.; Deutsch, Curtis A.; Tewksbury, Joshua J.; Vitt, Laurie J.; Hertz, Paul E.; Álvarez Pérez, Héctor J.; Garland, Theodore

2009-01-01

Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low. PMID:19324762

Why tropical forest lizards are vulnerable to climate warming.

PubMed

Huey, Raymond B; Deutsch, Curtis A; Tewksbury, Joshua J; Vitt, Laurie J; Hertz, Paul E; Alvarez Pérez, Héctor J; Garland, Theodore

2009-06-07

Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low.

Metabolic and physiological adjustment of Suaeda maritima to combined salinity and hypoxia

PubMed Central

Behr, Jan H.; Bouchereau, Alain; Berardocco, Solenne; Seal, Charlotte E.; Flowers, Timothy J.

2017-01-01

Background and Aims Suaeda maritima is a halophyte commonly found on coastal wetlands in the intertidal zone. Due to its habitat S. maritima has evolved tolerance to high salt concentrations and hypoxic conditions in the soil caused by periodic flooding. In the present work, the adaptive mechanisms of S. maritima to salinity combined with hypoxia were investigated on a physiological and metabolic level. Methods To compare the adaptive mechanisms to deficient, optimal and stressful salt concentrations, S. maritima plants were grown in a hydroponic culture under low, medium and high salt concentrations. Additionally, hypoxic conditions were applied to investigate the impact of hypoxia combined with different salt concentrations. A non-targeted metabolic approach was used to clarify the biochemical pathways underlying the metabolic and physiological adaptation mechanisms of S. maritima. Key Results Roots exposed to hypoxic conditions showed an increased level of tricarboxylic acid (TCA)-cycle intermediates such as succinate, malate and citrate. During hypoxia, the concentration of free amino acids increased in shoots and roots. Osmoprotectants such as proline and glycine betaine increased in concentrations as the external salinity was increased under hypoxic conditions. Conclusions The combination of high salinity and hypoxia caused an ionic imbalance and an increase of metabolites associated with osmotic stress and photorespiration, indicating a severe physiological and metabolic response under these conditions. Disturbed proline degradation in the roots induced an enhanced proline accumulation under hypoxia. The enhanced alanine fermentation combined with a partial flux of the TCA cycle might contribute to the tolerance of S. maritima to hypoxic conditions. PMID:28110268

Cockpit Adaptive Automation and Pilot Performance

NASA Technical Reports Server (NTRS)

Parasuraman, Raja

2001-01-01

The introduction of high-level automated systems in the aircraft cockpit has provided several benefits, e.g., new capabilities, enhanced operational efficiency, and reduced crew workload. At the same time, conventional 'static' automation has sometimes degraded human operator monitoring performance, increased workload, and reduced situation awareness. Adaptive automation represents an alternative to static automation. In this approach, task allocation between human operators and computer systems is flexible and context-dependent rather than static. Adaptive automation, or adaptive task allocation, is thought to provide for regulation of operator workload and performance, while preserving the benefits of static automation. In previous research we have reported beneficial effects of adaptive automation on the performance of both pilots and non-pilots of flight-related tasks. For adaptive systems to be viable, however, such benefits need to be examined jointly in the context of a single set of tasks. The studies carried out under this project evaluated a systematic method for combining different forms of adaptive automation. A model for effective combination of different forms of adaptive automation, based on matching adaptation to operator workload was proposed and tested. The model was evaluated in studies using IFR-rated pilots flying a general-aviation simulator. Performance, subjective, and physiological (heart rate variability, eye scan-paths) measures of workload were recorded. The studies compared workload-based adaptation to to non-adaptive control conditions and found evidence for systematic benefits of adaptive automation. The research provides an empirical basis for evaluating the effectiveness of adaptive automation in the cockpit. The results contribute to the development of design principles and guidelines for the implementation of adaptive automation in the cockpit, particularly in general aviation, and in other human-machine systems. Project goals were met or exceeded. The results of the research extended knowledge of automation-related performance decrements in pilots and demonstrated the positive effects of adaptive task allocation. In addition, several practical implications for cockpit automation design were drawn from the research conducted. A total of 12 articles deriving from the project were published.

Hypoxia signaling controls postnatal changes in cardiac mitochondrial morphology and function

PubMed Central

Neary, Marianne T.; Ng, Keat-Eng; Ludtmann, Marthe H.R.; Hall, Andrew R.; Piotrowska, Izabela; Ong, Sang-Bing; Hausenloy, Derek J.; Mohun, Timothy J.; Abramov, Andrey Y.; Breckenridge, Ross A.

2014-01-01

Fetal cardiomyocyte adaptation to low levels of oxygen in utero is incompletely understood, and is of interest as hypoxia tolerance is lost after birth, leading to vulnerability of adult cardiomyocytes. It is known that cardiac mitochondrial morphology, number and function change significantly following birth, although the underlying molecular mechanisms and physiological stimuli are undefined. Here we show that the decrease in cardiomyocyte HIF-signaling in cardiomyocytes immediately after birth acts as a physiological switch driving mitochondrial fusion and increased postnatal mitochondrial biogenesis. We also investigated mechanisms of ATP generation in embryonic cardiac mitochondria. We found that embryonic cardiac cardiomyocytes rely on both glycolysis and the tricarboxylic acid cycle to generate ATP, and that the balance between these two metabolic pathways in the heart is controlled around birth by the reduction in HIF signaling. We therefore propose that the increase in ambient oxygen encountered by the neonate at birth acts as a key physiological stimulus to cardiac mitochondrial adaptation. PMID:24984146

Development of countermeasures for use in space missions. [to adaptive response to space flight

NASA Technical Reports Server (NTRS)

Nicogossian, A. E. T.; Pool, S.; Huntoon, C. S. L.; Leonard, J. I.

1985-01-01

Several measures used to mitigate the inappropriate adaptive responses of space flight are investigated. Weighlessness results in a cephalic fluid shift, which causes a reduction in the circulating blood volume, and removal of weight bearing forces from musculoskeletal systems. The physiological changes that occur from one-g initiated hypovolemia and zero-g initiated fluild shifts are analyzed and compared. The role of barorecptors on the activation of the adrenergic responses that occurs as a result of hypovolemia is studied. The proper selection and administration of in-flight and post flight countermeasures, which include passive and active physical conditioning techniques, drugs, and vitamins are examined.

Intestinal adaptations in chronic kidney disease and the influence of gastric bypass surgery.

PubMed

Hatch, Marguerite

2014-09-01

Studies have shown that compensatory adaptations in gastrointestinal oxalate transport can impact the amount of oxalate excreted by the kidney. Hyperoxaluria is a major risk factor in the formation of kidney stones, and oxalate is derived from both the diet and the liver metabolism of glyoxylate. Although the intestine generally absorbs oxalate from dietary sources and can contribute as much as 50% of urinary oxalate, enteric oxalate elimination plays a significant role when renal function is compromised. While the mechanistic basis for these changes in the direction of intestinal oxalate movements in chronic renal failure involves an upregulation of angiotensin II receptors in the large intestine, enteric secretion/excretion of oxalate can also occur by mechanisms that are independent of angiotensin II. Most notably, the commensal bacterium Oxalobacter sp. interacts with the host enterocyte and promotes the movement of oxalate from the blood into the lumen, resulting in the beneficial effect of significantly lowering urinary oxalate excretion. Changes in the passive permeability of the intestine, such as in steatorrhoea and following gastric bypass, also promote oxalate absorption and hyperoxaluria. In summary, this report highlights the two-way physiological signalling between the gut and the kidney, which may help to alleviate the consequences of certain kidney diseases. © 2014 The Author. Experimental Physiology © 2014 The Physiological Society.

Physiological response and microRNA expression profiles in head kidney of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) exposed to acute cold stress.

PubMed

Qiang, Jun; Cui, Yan T; Tao, Fan Y; Bao, Wen J; He, Jie; Li, Xia H; Xu, Pao; Sun, Lan Y

2018-01-09

Cold stress has a serious impact on the overwintering survival and yield of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Understanding the physiological and molecular regulation mechanisms of low-temperature adaptation is necessary to help breed new tolerant strains. The semi-lethal low temperature of juvenile GIFT at 96 h was determined as 9.4 °C. We constructed and sequenced two small RNA libraries from head kidney tissues, one for the control (CO) group and one for the 9.4 °C-stressed (LTS) group, and identified 1736 and 1481 known microRNAs (miRNAs), and 164 and 152 novel miRNAs in the CO and LTS libraries, respectively. We verify the expression of nine up-regulated miRNAs and eight down-regulation miRNAs by qRT-PCR, and found their expression patterns were consistent with the sequencing results. We found that cold stress may have produced dysregulation of free radical and lipid metabolism, decreased superoxide dismutase activity, reduced respiratory burst and phagocytic activity of macrophages, increased malondialdehyde content, and adversely affected the physiological adaptation of GIFT, eventually leading to death. This study revealed interactions among miRNAs and signal regulated pathways in GIFT under cold stress that may help to understand the pathways involved in cold resistance.

Neuronal Responses to Physiological Stress

PubMed Central

Kagias, Konstantinos; Nehammer, Camilla; Pocock, Roger

2012-01-01

Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, due to an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level. PMID:23112806

Relationship between sociability toward humans and physiological stress in dogs.

PubMed

Shin, Yoon-Joo; Shin, Nam-Shik

2017-07-28

Sociability is an essential trait for dogs to successfully interact with humans. In this study, the relationship between sociability and physiological stress was examined. Additionally, whether differences exist between companion dogs (C group) and shelter dogs (S group) was examined. Overall, healthy 37 dogs (C group=21 and S group=16) were examined. After 5 min of walking, the dog and the owner (or the chief manager) rested freely in the experimental location for 5 min. The behavioral test with 6 categories was conducted to evaluate sociability over 4 min. The establishment of two groups (H group=dogs with high sociability; L group=dogs with low sociability) was supported by the statistical results of the behavioral tests. Saliva was collected before (P1) and after the test period (P2), and salivary cortisol levels were determined and statistically analyzed. The cortisol concentrations at P2 and the differences in concentrations between P1 and P2 (P2-P1) in the groups with high sociability were significantly lower than those in the groups with low sociability. These results may demonstrate that sociable dogs adapt more comfortably to strangers and unfamiliar situations. Meanwhile, there were significant differences in hormonal results between the C and S groups. For this reason, their sociability should be evaluated using behavioral and physiological assessments before re-adoption to ensure their successful adaptation.

Physiological adaptations to low-volume, high-intensity interval training in health and disease.

PubMed

Gibala, Martin J; Little, Jonathan P; Macdonald, Maureen J; Hawley, John A

2012-03-01

Exercise training is a clinically proven, cost-effective, primary intervention that delays and in many cases prevents the health burdens associated with many chronic diseases. However, the precise type and dose of exercise needed to accrue health benefits is a contentious issue with no clear consensus recommendations for the prevention of inactivity-related disorders and chronic diseases. A growing body of evidence demonstrates that high-intensity interval training (HIT) can serve as an effective alternate to traditional endurance-based training, inducing similar or even superior physiological adaptations in healthy individuals and diseased populations, at least when compared on a matched-work basis. While less well studied, low-volume HIT can also stimulate physiological remodelling comparable to moderate-intensity continuous training despite a substantially lower time commitment and reduced total exercise volume. Such findings are important given that 'lack of time' remains the most commonly cited barrier to regular exercise participation. Here we review some of the mechanisms responsible for improved skeletal muscle metabolic control and changes in cardiovascular function in response to low-volume HIT. We also consider the limited evidence regarding the potential application of HIT to people with, or at risk for, cardiometabolic disorders including type 2 diabetes. Finally, we provide insight on the utility of low-volume HIT for improving performance in athletes and highlight suggestions for future research.

Edmund Goodwyn and the first description of diving bradycardia.

PubMed

Vega, Jose L

2017-08-01

Diving bradycardia is a primordial oxygen-conserving reflex by which the heart rate of air-breathing vertebrates, including humans, slows down in response to water immersion. Its discovery is attributed to Paul Bert, whose seminal observation was published in 1870 as part of a series of experiments that examined physiological adaptations to asphyxia in ducks and other animals. However, Edmund Goodwyn, a British physician who studied medicine at the University of Edinburgh, had already described this reflex in his doctoral thesis, which was originally published in Latin in 1786 and again in English in 1788. Ironically, even though Goodwyn's work has yet to be recognized in the diving physiology literature, it was referenced in the very publication that contains Bert's original observation. Thus this article brings Goodwyn's work and its historical context to light and argues that he should be credited with the first description of diving bradycardia. Copyright © 2017 the American Physiological Society.

Physiology response of the indigenous cattle breeds to the environment in West Sumbawa, Indonesia

NASA Astrophysics Data System (ADS)

Aritonang, S. B.; Yuniati, R.; Abinawanto, Imron, M.; Bowolaksono, A.

2017-07-01

Heat stress in cattle welfare is a growing concern because of increase in ambient temperature due to global warming. Physiological adaptation is as a way to survive and reproduce by regulation internal body temperature. West Sumbawa is a dry tropic area in eastern Indonesia where its temperature range is 24-38 °C and relative humidity is 50-90 %. This study aimed to determine the physiological response of indigenous cattle i.e. Bali cattle and Sumbawa Ongole cattle to the environment in West Sumbawa. Skin and rectal temperature and respiration rate within one minute were measured as physiology profiles from seven Bali cattle and two Sumbawa Ongole cattle. They were measured every 7.00 am and 15.00 pm for five consecutive days in August 2016. The results of measurements physiology profiles differ significantly between morning and afternoon among cattle breeds. Body temperature and respiration rate were significantly different among breeds (p < 0.05). Body temperature was lower but respiration rate of Sumbawa Ongole was higher than Bali cattle. Increased respiration rate of breeds was positively correlated with Temperature and Humidity Index (THI) value (p < 0.05), but neither was body temperature. Physiological response of Bali cattle to environmental West Sumbawa through the increase in body temperature, whereas Sumbawa Ongole cattle through increasing in respiration rate.

Increased leaf mesophyll porosity following transient retinoblastoma-related protein silencing is revealed by microcomputed tomography imaging and leads to a system-level physiological response to the altered cell division pattern

PubMed Central

Dorca-Fornell, Carmen; Pajor, Radoslaw; Lehmeier, Christoph; Pérez-Bueno, Marísa; Bauch, Marion; Sloan, Jen; Osborne, Colin; Rolfe, Stephen; Sturrock, Craig; Mooney, Sacha; Fleming, Andrew

2013-01-01

The causal relationship between cell division and growth in plants is complex. Although altered expression of cell-cycle genes frequently leads to altered organ growth, there are many examples where manipulation of the division machinery leads to a limited outcome at the level of organ form, despite changes in constituent cell size. One possibility, which has been under-explored, is that altered division patterns resulting from manipulation of cell-cycle gene expression alter the physiology of the organ, and that this has an effect on growth. We performed a series of experiments on retinoblastoma-related protein (RBR), a well characterized regulator of the cell cycle, to investigate the outcome of altered cell division on leaf physiology. Our approach involved combination of high-resolution microCT imaging and physiological analysis with a transient gene induction system, providing a powerful approach for the study of developmental physiology. Our investigation identifies a new role for RBR in mesophyll differentiation that affects tissue porosity and the distribution of air space within the leaf. The data demonstrate the importance of RBR in early leaf development and the extent to which physiology adapts to modified cellular architecture resulting from altered cell-cycle gene expression. PMID:24118480

Why Are There Old People? Senescence as Biological and Cultural Preparedness for the Transmission of Information.

ERIC Educational Resources Information Center

Mergler, N.L.; Goldstein, M.D.

1983-01-01

Biological theories of adaptation are used to generate a model of human cognitive development in which physiological and cognitive change in aged persons can be understood as an adaptive stage of development. Related literature is reviewed that focuses on the elderly as information transmitters and on the psychology of "telling."…

Cortisol Reactivity to Social Stress as a Mediator of Early Adversity on Risk and Adaptive Outcomes

ERIC Educational Resources Information Center

Conradt, Elisabeth; Abar, Beau; Lester, Barry M.; LaGasse, Linda L.; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles R.; Whitaker, Toni M.; Hammond, Jane A.

2014-01-01

Children chronically exposed to stress early in life are at increased risk for maladaptive outcomes, though the physiological mechanisms driving these effects are unknown. Cortisol reactivity was tested as a mediator of the relation between prenatal substance exposure and/or early adversity on adaptive and maladaptive outcomes. Data were drawn…

Psychosocial Adaptation and Depressive Manifestations in High-Risk Pregnant Women: Implications for Clinical Practice.

PubMed

Fiskin, Gamze; Kaydirak, Meltem Mecdi; Oskay, Umran Yesiltepe

2017-02-01

High-risk pregnancy research has focused primarily on psychological well-being. The aim is to determine psychosocial adaptation and depression levels of pregnant women who were admitted to hospital with diagnosis of high-risk pregnancy. This study was descriptive. Sampling was composed of 122 high-risk pregnant women who were hospitalized in the perinatology service of Istanbul University Medical School, Department of Obstetrics and Gynecology between January 1, 2014, and May 31, 2014, and met the study criteria. The Pregnant Introduction Form, Psychosocial Adjustment of Illness Scale-Self Report, and CES Depression Scale were used. Of high-risk pregnant women, 47% were found to have a poor level of psychosocial adaptation and 57% presented with depressive symptoms. There were statistically significant difference found between the levels of psychosocial adaptation and status of depressive manifestations. The difference between the average scores increased as the adaptation levels weaken and the pregnant women with a poor level of psychosocial adaptation showed more depressive manifestations. The results of this study indicate that, depending on the high-risk pregnancy status, pregnant women experience difficulty in adaptation to their current status and pregnant women with a poor level of psychosocial adaptation showed more depressive manifestations. Nurses should deliver care in high-risk pregnancies with the awareness of physiological needs as well the psychosocial needs of pregnant women, and information meetings should be held in order to increase the psychosocial support of their families and decrease their tendency toward depression. Nursing initiatives should be developed with further studies for the psychosocial adaptation of high-risk pregnancy and reduction of the depressive manifestations. © 2016 Sigma Theta Tau International.

Dim light adaptation attenuates acute melatonin suppression in humans.

PubMed

Jasser, Samar A; Hanifin, John P; Rollag, Mark D; Brainard, George C

2006-10-01

Abstract Studies in rodents with retinal degeneration indicated that neither the rod nor the cone photoreceptors obligatorily participate in circadian responses to light, including melatonin suppression and photoperiodic response. Yet there is a residual phase-shifting response in melanopsin knockout mice, which suggests an alternate or redundant means for light input to the SCN of the hypothalamus. The findings of Aggelopoulos and Meissl suggest a complex, dynamic interrelationship between the classic visual photoreceptors and SCN cell sensitivity to light stimuli, relative to various adaptive lighting conditions. These studies raised the possibility that the phototransductive physiology of the retinohypothalamic tract in humans might be modulated by the visual rod and cone photoreceptors. The aim of the following two-part study was to test the hypothesis that dim light adaptation will dampen the subsequent suppression of melatonin by monochromatic light in healthy human subjects. Each experiment included 5 female and 3 male human subjects between the ages of 18 and 30 years, with normal color vision. Dim white light and darkness adaptation exposures occurred between midnight and 0200 h, and a full-field 460-nm light exposure subsequently occurred between 0200 and 0330-h for each adaptation condition, at 2 different intensities. Plasma samples were drawn following the 2-h adaptation, as well as after the 460-nm monochromatic light exposure, and melatonin was measured by radioimmunoassay. Comparison of melatonin suppression responses to monochromatic light in both studies revealed a loss of significant suppression after dim white light adaptation compared with dark adaptation (p < 0.04 and p < 0.01). These findings indicate that the activity of the novel circadian photoreceptive system in humans is subject to subthreshold modulation of its sensitivity to subsequent monochromatic light exposure, varying with the conditions of light adaptation prior to exposure.

Measuring the ability of military aircrews to adapt to perceived stressors when undergoing centrifuge training.

PubMed

Wang, Jenhung; Lin, Pei-Chun; Li, Shih-Chin

2014-01-01

This study assessed the ability of military aircrews to adapt to stressors when undergoing centrifuge training and determined what equipment items caused perceived stress and needed to be upgraded. We used questionnaires and the Rasch model to measure aircrew personnel's ability to adapt to centrifuge training. The measurement items were ranked by 611 military aircrew personnel. Analytical results indicated that the majority of the stress perceived by aircrew personnel resulted from the lightproof cockpit without outer reference. This study prioritized the equipment requiring updating as the lightproof cockpit design, the dim lighting of the cockpit, and the pedal design. A significant difference was found between pilot and non-pilot subjects' stress from the pedal design; and considerable association was discernible between the seat angle design and flight hours accrued. The study results provide aviators, astronauts, and air forces with reliable information as to which equipment items need to be urgently upgraded as their present physiological and psychological effects can affect the effectiveness of centrifuge training.

Adaptation to Chronic Nutritional Stress Leads to Reduced Dependence on Microbiota in Drosophila melanogaster

PubMed Central

Kolly, Sylvain; van der Meer, Jan R.; Kawecki, Tadeusz J.

2017-01-01

ABSTRACT Numerous studies have shown that animal nutrition is tightly linked to gut microbiota, especially under nutritional stress. In Drosophila melanogaster, microbiota are known to promote juvenile growth, development, and survival on poor diets, mainly through enhanced digestion leading to changes in hormonal signaling. Here, we show that this reliance on microbiota is greatly reduced in replicated Drosophila populations that became genetically adapted to a poor larval diet in the course of over 170 generations of experimental evolution. Protein and polysaccharide digestion in these poor-diet-adapted populations became much less dependent on colonization with microbiota. This was accompanied by changes in expression levels of dFOXO transcription factor, a key regulator of cell growth and survival, and many of its targets. These evolutionary changes in the expression of dFOXO targets to a large degree mimic the response of the same genes to microbiota, suggesting that the evolutionary adaptation to poor diet acted on mechanisms that normally mediate the response to microbiota. Our study suggests that some metazoans have retained the evolutionary potential to adapt their physiology such that association with microbiota may become optional rather than essential. PMID:29066546

Genetic Variants in Serotonin and Corticosteroid Systems Modulate Neuroendocrine and Cardiovascular Responses to Intense Stress

DTIC Science & Technology

2014-05-10

d G r r o o s p c D t e b b o i m h a S c t a t m c h M.K. Taylor et al. / Behaviou . Introduction Psychological and physiological stressors ignite...categorically stressful context, quantified by severe disruption of physiological and self-report indices [30,31]. 2.2. Inclusion, exclusion, and compliance...military environments. eferences [1] McEwen BS. Physiology and neurobiology of stress and adaptation: central role of the brain. Physiol Rev 2007;87

Nutrition for power sports: middle-distance running, track cycling, rowing, canoeing/kayaking, and swimming.

PubMed

Stellingwerff, Trent; Maughan, Ronald J; Burke, Louise M

2011-01-01

Contemporary training for power sports involves diverse routines that place a wide array of physiological demands on the athlete. This requires a multi-faceted nutritional strategy to support both general training needs--tailored to specific training phases--as well as the acute demands of competition. Elite power sport athletes have high training intensities and volumes for most of the training season, so energy intake must be sufficient to support recovery and adaptation. Low pre-exercise muscle glycogen reduces high-intensity performance, so daily carbohydrate intake must be emphasized throughout training and competition phases. There is strong evidence to suggest that the timing, type, and amount of protein intake influence post-exercise recovery and adaptation. Most power sports feature demanding competition schedules, which require aggressive nutritional recovery strategies to optimize muscle glycogen resynthesis. Various power sports have different optimum body compositions and body weight requirements, but increasing the power-to-weight ratio during the championship season can lead to significant performance benefits for most athletes. Both intra- and extracellular buffering agents may enhance performance, but more research is needed to examine the potential long-term impact of buffering agents on training adaptation. Interactions between training, desired physiological adaptations, competition, and nutrition require an individual approach and should be continuously adjusted and adapted.