Polyamines in plants: biosynthesis from arginine, and metabolic, physiological, and stress-response roles

USDA-ARS?s Scientific Manuscript database

Biogenic amines in all organisms including plants affect a myriad of growth and developmental processes. Therefore, there is continued interest in understanding their (here polyamines) biosynthesis and functional roles in regulating plant metabolism, physiology and development. The role of polyamine...

The Integrative Role of the Sigh in Psychology, Physiology, Pathology, and Neurobiology

PubMed Central

Ramirez, Jan-Marino

2015-01-01

“Sighs, tears, grief, distress” expresses Johann Sebastian Bach in a musical example for the relationship between sighs and deep emotions. This review explores the neurobiological basis of the sigh and its relationship with psychology, physiology, and pathology. Sighs monitor changes in brain states, induce arousal, and reset breathing variability. These behavioral roles homeostatically regulate breathing stability under physiological and pathological conditions. Sighs evoked in hypoxia evoke arousal and thereby become critical for survival. Hypoarousal and failure to sigh have been associated with sudden infant death syndrome. Increased breathing irregularity may provoke excessive sighing and hyperarousal, a behavioral sequence that may play a role in panic disorders. Essential for generating sighs and breathing is the pre-Bötzinger complex. Modulatory and synaptic interactions within this local network and between networks located in the brainstem, cerebellum, cortex, hypothalamus, amygdala, and the periaqueductal gray may govern the relationships between physiology, psychology, and pathology. Unraveling these circuits will lead to a better understanding of how we balance emotions and how emotions become pathological. PMID:24746045

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.

Large-Scale Bioinformatics Analysis of Bacillus Genomes Uncovers Conserved Roles of Natural Products in Bacterial Physiology.

PubMed

Grubbs, Kirk J; Bleich, Rachel M; Santa Maria, Kevin C; Allen, Scott E; Farag, Sherif; Shank, Elizabeth A; Bowers, Albert A

2017-01-01

Bacteria possess an amazing capacity to synthesize a diverse range of structurally complex, bioactive natural products known as specialized (or secondary) metabolites. Many of these specialized metabolites are used as clinical therapeutics, while others have important ecological roles in microbial communities. The biosynthetic gene clusters (BGCs) that generate these metabolites can be identified in bacterial genome sequences using their highly conserved genetic features. We analyzed an unprecedented 1,566 bacterial genomes from Bacillus species and identified nearly 20,000 BGCs. By comparing these BGCs to one another as well as a curated set of known specialized metabolite BGCs, we discovered that the majority of Bacillus natural products are comprised of a small set of highly conserved, well-distributed, known natural product compounds. Most of these metabolites have important roles influencing the physiology and development of Bacillus species. We identified, in addition to these characterized compounds, many unique, weakly conserved BGCs scattered across the genus that are predicted to encode unknown natural products. Many of these "singleton" BGCs appear to have been acquired via horizontal gene transfer. Based on this large-scale characterization of metabolite production in the Bacilli , we go on to connect the alkylpyrones, natural products that are highly conserved but previously biologically uncharacterized, to a role in Bacillus physiology: inhibiting spore development. IMPORTANCE Bacilli are capable of producing a diverse array of specialized metabolites, many of which have gained attention for their roles as signals that affect bacterial physiology and development. Up to this point, however, the Bacillus genus's metabolic capacity has been underexplored. We undertook a deep genomic analysis of 1,566 Bacillus genomes to understand the full spectrum of metabolites that this bacterial group can make. We discovered that the majority of the specialized

Nitric oxide: a physiologic messenger.

PubMed

Lowenstein, C J; Dinerman, J L; Snyder, S H

1994-02-01

To review the physiologic role of nitric oxide, an unusual messenger molecule that mediates blood vessel relaxation, neurotransmission, and pathogen suppression. A MEDLINE search of articles published from 1987 to 1993 that addressed nitric oxide and the enzyme that synthesizes it, nitric oxide synthase. Animal and human studies were selected from 3044 articles to analyze the clinical importance of nitric oxide. Descriptions of the structure and function of nitric oxide synthase were selected to show how nitric oxide acts as a biological messenger molecule. Biochemical and physiologic studies were analyzed if the same results were found by three or more independent observers. Two major classes of nitric oxide synthase enzymes produce nitric oxide. The constitutive isoforms found in endothelial cells and neurons release small amounts of nitric oxide for brief periods to signal adjacent cells, whereas the inducible isoform found in macrophages releases large amounts of nitric oxide continuously to eliminate bacteria and parasites. By diffusing into adjacent cells and binding to enzymes that contain iron, nitric oxide plays many important physiologic roles. It regulates blood pressure, transmits signals between neurons, and suppresses pathogens. Excess amounts, however, can damage host cells, causing neurotoxicity during strokes and causing the hypotension associated with sepsis. Nitric oxide is a simple molecule with many physiologic roles in the cardiovascular, neurologic, and immune systems. Although the general principles of nitric oxide synthesis are known, further research is necessary to determine what role it plays in causing disease.

Prohibitin( PHB) roles in granulosa cell physiology.

PubMed

Chowdhury, Indrajit; Thomas, Kelwyn; Thompson, Winston E

2016-01-01

Ovarian granulosa cells (GC) play an important role in the growth and development of the follicle in the process known as folliculogenesis. In the present review, we focus on recent developments in prohibitin (PHB) research in relation to GC physiological functions. PHB is a member of a highly conserved eukaryotic protein family containing the repressor of estrogen activity (REA)/stomatin/PHB/flotillin/HflK/C (SPFH) domain (also known as the PHB domain) found in diverse species from prokaryotes to eukaryotes. PHB is ubiquitously expressed in a circulating free form or is present in multiple cellular compartments including mitochondria, nucleus and plasma membrane. In mitochondria, PHB is anchored to the mitochondrial inner membrane and forms complexes with the ATPases associated with proteases having diverse cellular activities. PHB continuously shuttles between the mitochondria, cytosol and nucleus. In the nucleus, PHB interacts with various transcription factors and modulates transcriptional activity directly or through interactions with chromatin remodeling proteins. Many functions have been attributed to the mitochondrial and nuclear PHB complexes such as cellular differentiation, anti-proliferation, morphogenesis and maintenance of the functional integrity of the mitochondria. However, to date, the regulation of PHB expression patterns and GC physiological functions are not completely understood.

Prohibitin (PHB) roles in granulosa cell physiology

PubMed Central

Chowdhury, Indrajit; Thomas, Kelwyn; Thompson, Winston E.

2015-01-01

Ovarian granulosa cells (GC) play an important role in the growth and development of the follicle in the process known as folliculogenesis. In the present review, we focus on the recent developments in prohibitin (PHB) research in relation to GC physiological functions. PHB is a member of highly conserved eukaryotic protein family containing the repressor of estrogen activity (REA)/stomatin/prohibitin/flotillin/HflK/C (SPFH) domain [also known as the PHB domain] found in divergent species from prokaryotes to eukaryotes. PHB is ubiquitously expressed either in circulating free form or is present in multiple cellular compartments including mitochondria, nucleus and plasma membrane. In mitochondria, PHB is anchored to the mitochondrial inner membrane (IMM), and form complexes with the ATPases Associated with diverse cellular Activities (m-AAA) proteases. PHB continuously shuttles between the mitochondria, cytosol and nucleus. In the nucleus, PHB interacts with various transcription factors and modulate transcriptional activity directly or through interactions with chromatin remodeling proteins. Multiple functions have been attributed to the mitochondrial and nuclear prohibitin complexes such as cellular differentiation, anti-proliferation, morphogenesis and maintaining the functional integrity of the mitochondria. However, to date, the regulation of PHB expression patterns and GC physiological functions are not completely understood. PMID:26496733

Causal Structure of Brain Physiology after Brain Injury from Subarachnoid Hemorrhage.

PubMed

Claassen, Jan; Rahman, Shah Atiqur; Huang, Yuxiao; Frey, Hans-Peter; Schmidt, J Michael; Albers, David; Falo, Cristina Maria; Park, Soojin; Agarwal, Sachin; Connolly, E Sander; Kleinberg, Samantha

2016-01-01

High frequency physiologic data are routinely generated for intensive care patients. While massive amounts of data make it difficult for clinicians to extract meaningful signals, these data could provide insight into the state of critically ill patients and guide interventions. We develop uniquely customized computational methods to uncover the causal structure within systemic and brain physiologic measures recorded in a neurological intensive care unit after subarachnoid hemorrhage. While the data have many missing values, poor signal-to-noise ratio, and are composed from a heterogeneous patient population, our advanced imputation and causal inference techniques enable physiologic models to be learned for individuals. Our analyses confirm that complex physiologic relationships including demand and supply of oxygen underlie brain oxygen measurements and that mechanisms for brain swelling early after injury may differ from those that develop in a delayed fashion. These inference methods will enable wider use of ICU data to understand patient physiology.

The Role of Biotin in Bacterial Physiology and Virulence: a Novel Antibiotic Target for Mycobacterium tuberculosis.

PubMed

Salaemae, Wanisa; Booker, Grant W; Polyak, Steven W

2016-04-01

Biotin is an essential cofactor for enzymes present in key metabolic pathways such as fatty acid biosynthesis, replenishment of the tricarboxylic acid cycle, and amino acid metabolism. Biotin is synthesized de novo in microorganisms, plants, and fungi, but this metabolic activity is absent in mammals, making biotin biosynthesis an attractive target for antibiotic discovery. In particular, biotin biosynthesis plays important metabolic roles as the sole source of biotin in all stages of the Mycobacterium tuberculosis life cycle due to the lack of a transporter for scavenging exogenous biotin. Biotin is intimately associated with lipid synthesis where the products form key components of the mycobacterial cell membrane that are critical for bacterial survival and pathogenesis. In this review we discuss the central role of biotin in bacterial physiology and highlight studies that demonstrate the importance of its biosynthesis for virulence. The structural biology of the known biotin synthetic enzymes is described alongside studies using structure-guided design, phenotypic screening, and fragment-based approaches to drug discovery as routes to new antituberculosis agents.

The role of nitric oxide in the physiology and pathophysiology of the exocrine pancreas.

PubMed

Hegyi, Péter; Rakonczay, Zoltán

2011-11-15

Nitric oxide (NO), a ubiquitous gaseous signaling molecule, contributes to both pancreatic physiology and pathophysiology. The present review provides a general overview of NO synthesis, signaling, and function. Further, it specifically discusses NO metabolism and its effects in the exocrine pancreas and focuses on the role of NO in the pathogenesis of acute pancreatitis and pancreatic ischemia/reperfusion injury. Unfortunately, the role of NO in pancreatic physiology and pathophysiology remains controversial in numerous areas. Many questions regarding the messenger molecule still remain unanswered. Probably the least is known about the downstream targets of NO, which need to be identified, especially at the molecular level.

The emerging physiological roles of the SLC14A family of urea transporters

PubMed Central

Stewart, Gavin

2011-01-01

In mammals, urea is the main nitrogenous breakdown product of protein catabolism and is produced in the liver. In certain tissues, the movement of urea across cell membranes is specifically mediated by a group of proteins known as the SLC14A family of facilitative urea transporters. These proteins are derived from two distinct genes, UT-A (SLC14A2) and UT-B (SLC14A1). Facilitative urea transporters play an important role in two major physiological processes – urinary concentration and urea nitrogen salvaging. Although UT-A and UT-B transporters both have a similar basic structure and mediate the transport of urea in a facilitative manner, there are a number of significant differences between them. UT-A transporters are mainly found in the kidney, are highly specific for urea, have relatively lower transport rates and are highly regulated at both gene expression and cellular localization levels. In contrast, UT-B transporters are more widespread in their tissue location, transport both urea and water, have a relatively high transport rate, are inhibited by mercurial compounds and currently appear to be less acutely regulated. This review details the fundamental research that has so far been performed to investigate the function and physiological significance of these two types of urea transporters. PMID:21449978

Role of Ergothioneine in Microbial Physiology and Pathogenesis

PubMed Central

Cumming, Bridgette M.; Chinta, Krishna C.; Reddy, Vineel P.

2018-01-01

Abstract Significance: L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria, and some fungi. In contrast to other low-molecular-weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables the survival of microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection. Recent Advances: Ergothioneine has been reported to maintain bioenergetic homeostasis in Mtb and protect Mtb against oxidative stresses, thereby enhancing the virulence of Mtb in a mouse model. Furthermore, ergothioneine augments the resistance of Mtb to current frontline anti-TB drugs. Recently, an opportunistic fungus, Aspergillus fumigatus, which infects immunocompromised individuals, has been found to produce ergothioneine, which is important in conidial health and germination, and contributes to the fungal resistance against redox stresses. Critical Issues: The molecular mechanisms of the functions of ergothioneine in microbial physiology and pathogenesis are poorly understood. It is currently not known if ergothioneine is used in detoxification or antioxidant enzymatic pathways. As ergothioneine is involved in bioenergetic and redox homeostasis and antibiotic susceptibility of Mtb, it is of utmost importance to advance our understanding of these mechanisms. Future Directions: A clear understanding of the role of ergothioneine in microbes will advance our knowledge of how this thione enhances microbial virulence and resistance to the host's defense mechanisms to avoid complete eradication. Antioxid. Redox Signal. 28, 431–444. PMID:28791878

Role of Ergothioneine in Microbial Physiology and Pathogenesis.

PubMed

Cumming, Bridgette M; Chinta, Krishna C; Reddy, Vineel P; Steyn, Adrie J C

2018-02-20

L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria, and some fungi. In contrast to other low-molecular-weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables the survival of microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection. Recent Advances: Ergothioneine has been reported to maintain bioenergetic homeostasis in Mtb and protect Mtb against oxidative stresses, thereby enhancing the virulence of Mtb in a mouse model. Furthermore, ergothioneine augments the resistance of Mtb to current frontline anti-TB drugs. Recently, an opportunistic fungus, Aspergillus fumigatus, which infects immunocompromised individuals, has been found to produce ergothioneine, which is important in conidial health and germination, and contributes to the fungal resistance against redox stresses. The molecular mechanisms of the functions of ergothioneine in microbial physiology and pathogenesis are poorly understood. It is currently not known if ergothioneine is used in detoxification or antioxidant enzymatic pathways. As ergothioneine is involved in bioenergetic and redox homeostasis and antibiotic susceptibility of Mtb, it is of utmost importance to advance our understanding of these mechanisms. A clear understanding of the role of ergothioneine in microbes will advance our knowledge of how this thione enhances microbial virulence and resistance to the host's defense mechanisms to avoid complete eradication. Antioxid. Redox Signal. 28, 431-444.

Physiological regulation and metabolic role of browning in white adipose tissue.

PubMed

Jankovic, Aleksandra; Otasevic, Vesna; Stancic, Ana; Buzadzic, Biljana; Korac, Aleksandra; Korac, Bato

2017-09-01

Great progress has been made in our understanding of the browning process in white adipose tissue (WAT) in rodents. The recognition that i) adult humans have physiologically inducible brown adipose tissue (BAT) that may facilitate resistance to obesity and ii) that adult human BAT molecularly and functionally resembles beige adipose tissue in rodents, reignited optimism that obesity and obesity-related diabetes type 2 can be battled by controlling the browning of WAT. In this review the main cellular mechanisms and molecular mediators of browning of WAT in different physiological states are summarized. The relevance of browning of WAT in metabolic health is considered primarily through a modulation of biological role of fat tissue in overall metabolic homeostasis.

Sugar for the brain: the role of glucose in physiological and pathological brain function

PubMed Central

Mergenthaler, Philipp; Lindauer, Ute; Dienel, Gerald A.; Meisel, Andreas

2013-01-01

The mammalian brain depends upon glucose as its main source of energy, and tight regulation of glucose metabolism is critical for brain physiology. Consistent with its critical role for physiological brain function, disruption of normal glucose metabolism as well as its interdependence with cell death pathways forms the pathophysiological basis for many brain disorders. Here, we review recent advances in understanding how glucose metabolism sustains basic brain physiology. We aim at synthesizing these findings to form a comprehensive picture of the cooperation required between different systems and cell types, and the specific breakdowns in this cooperation which lead to disease. PMID:23968694

Biology 23. Unit One -- The Cell: Structure and Physiology.

ERIC Educational Resources Information Center

Nederland Independent School District, TX.

GRADES OR AGES: Not given. SUBJECT MATTER: Biology, the structure and physiology of the cell. ORGANIZATION AND PHYSICAL APPEARANCE: There are four sections: a) objectives for the unit, b) bibliography, c) activities, and d) evaluation. The guide is directed to the student rather than the teacher. The guide is mimeographed and stapled, with no…

Improved in-cell structure determination of proteins at near-physiological concentration

PubMed Central

Ikeya, Teppei; Hanashima, Tomomi; Hosoya, Saori; Shimazaki, Manato; Ikeda, Shiro; Mishima, Masaki; Güntert, Peter; Ito, Yutaka

2016-01-01

Investigating three-dimensional (3D) structures of proteins in living cells by in-cell nuclear magnetic resonance (NMR) spectroscopy opens an avenue towards understanding the structural basis of their functions and physical properties under physiological conditions inside cells. In-cell NMR provides data at atomic resolution non-invasively, and has been used to detect protein-protein interactions, thermodynamics of protein stability, the behavior of intrinsically disordered proteins, etc. in cells. However, so far only a single de novo 3D protein structure could be determined based on data derived only from in-cell NMR. Here we introduce methods that enable in-cell NMR protein structure determination for a larger number of proteins at concentrations that approach physiological ones. The new methods comprise (1) advances in the processing of non-uniformly sampled NMR data, which reduces the measurement time for the intrinsically short-lived in-cell NMR samples, (2) automatic chemical shift assignment for obtaining an optimal resonance assignment, and (3) structure refinement with Bayesian inference, which makes it possible to calculate accurate 3D protein structures from sparse data sets of conformational restraints. As an example application we determined the structure of the B1 domain of protein G at about 250 μM concentration in living E. coli cells. PMID:27910948

Stomatal structure and physiology do not explain differences in water use among montane eucalypts.

PubMed

Gharun, Mana; Turnbull, Tarryn L; Pfautsch, Sebastian; Adams, Mark A

2015-04-01

Understanding the regulation of water use at the whole-tree scale is critical to advancing the utility of physiological ecology, for example in its role in predictive hydrology of forested catchments. For three eucalypt species that dominate high-elevation catchments in south-eastern Australia, we examined if whole-tree water use could be related to three widely discussed regulators of water use: stomatal anatomy, sensitivity of stomata [i.e. stomatal conductance (g(s))] to environmental influences, and sapwood area. While daily tree water use varied sixfold among species, sap velocity and sapwood area varied in parallel. Combined, stomatal structure and physiology could not explain differences in species-specific water use. Species which exhibited the fastest (Eucalyptus delegatensis) and slowest (Eucalyptus pauciflora) rates of water use both exhibited greater capacity for physiological control of g(s) [indicated by sensitivity to vapour pressure deficit (VPD)] and a reduced capacity to limit g(s) anatomically [indicated by greater potential g(s) (g(max))]. Conversely, g(s) was insensitive to VPD and g(max) was lowest for Eucalyptus radiata, the species showing intermediate rates of water use. Improved knowledge of stomatal anatomy will help us to understand the capacity of species to regulate leaf-level water loss, but seems likely to remain of limited use for explaining rates of whole-tree water use in montane eucalypts at the catchment scale.

Early Childcare, Executive Functioning, and the Moderating Role of Early Stress Physiology

ERIC Educational Resources Information Center

Berry, Daniel; Willoughby, Michael T.; Blair, Clancy; Ursache, Alexandra; Granger, Douglas A.

2014-01-01

Intervention studies indicate that children's childcare experiences can be leveraged to support the development of executive functioning (EF). The role of more normative childcare experiences is less clear. Increasingly, theory and empirical work suggest that individual differences in children's physiological stress systems may be associated with…

Sugar for the brain: the role of glucose in physiological and pathological brain function.

PubMed

Mergenthaler, Philipp; Lindauer, Ute; Dienel, Gerald A; Meisel, Andreas

2013-10-01

The mammalian brain depends upon glucose as its main source of energy, and tight regulation of glucose metabolism is critical for brain physiology. Consistent with its critical role for physiological brain function, disruption of normal glucose metabolism as well as its interdependence with cell death pathways forms the pathophysiological basis for many brain disorders. Here, we review recent advances in understanding how glucose metabolism sustains basic brain physiology. We synthesize these findings to form a comprehensive picture of the cooperation required between different systems and cell types, and the specific breakdowns in this cooperation that lead to disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

The role of physiological traits in assortment among and within fish shoals

PubMed Central

Marras, Stefano

2017-01-01

Individuals of gregarious species often group with conspecifics to which they are phenotypically similar. This among-group assortment has been studied for body size, sex and relatedness. However, the role of physiological traits has been largely overlooked. Here, we discuss mechanisms by which physiological traits—particularly those related to metabolism and locomotor performance—may result in phenotypic assortment not only among but also within animal groups. At the among-group level, varying combinations of passive assortment, active assortment, phenotypic plasticity and selective mortality may generate phenotypic differences among groups. Even within groups, however, individual variation in energy requirements, aerobic and anaerobic capacity, neurological lateralization and tolerance to environmental stressors are likely to produce differences in the spatial location of individuals or associations between group-mates with specific physiological phenotypes. Owing to the greater availability of empirical research, we focus on groups of fishes (i.e. shoals and schools). Increased knowledge of physiological mechanisms influencing among- and within-group assortment will enhance our understanding of fundamental concepts regarding optimal group size, predator avoidance, group cohesion, information transfer, life-history strategies and the evolutionary effects of group membership. In a broader perspective, predicting animal responses to environmental change will be impossible without a comprehensive understanding of the physiological basis of the formation and functioning of animal social groups. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’. PMID:28673911

Molecular Aspects of Structure, Gating, and Physiology of pH-Sensitive Background K2P and Kir K+-Transport Channels

PubMed Central

Sepúlveda, Francisco V.; Pablo Cid, L.; Teulon, Jacques; Niemeyer, María Isabel

2015-01-01

K+ channels fulfill roles spanning from the control of excitability to the regulation of transepithelial transport. Here we review two groups of K+ channels, pH-regulated K2P channels and the transport group of Kir channels. After considering advances in the molecular aspects of their gating based on structural and functional studies, we examine their participation in certain chosen physiological and pathophysiological scenarios. Crystal structures of K2P and Kir channels reveal rather unique features with important consequences for the gating mechanisms. Important tasks of these channels are discussed in kidney physiology and disease, K+ homeostasis in the brain by Kir channel-equipped glia, and central functions in the hearing mechanism in the inner ear and in acid secretion by parietal cells in the stomach. K2P channels fulfill a crucial part in central chemoreception probably by virtue of their pH sensitivity and are central to adrenal secretion of aldosterone. Finally, some unorthodox behaviors of the selectivity filters of K2P channels might explain their normal and pathological functions. Although a great deal has been learned about structure, molecular details of gating, and physiological functions of K2P and Kir K+-transport channels, this has been only scratching at the surface. More molecular and animal studies are clearly needed to deepen our knowledge. PMID:25540142

Crystal structure and potential physiological role of zebra fish thioesterase superfamily member 2 (fTHEM2)

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

Yu, Shanshan; Li, Han; Gao, Feng

2015-08-07

Thioesterase superfamily member 2 (THEM2) is an essential protein for mammalian cell proliferation. It belongs to the hotdog-fold thioesterase superfamily and catalyzes hydrolysis of thioester bonds of acyl-CoA in vitro, while its in vivo function remains unrevealed. In this study, Zebra fish was selected as a model organism to facilitate the investigations on THEM2. First, we solved the crystal structure of recombinant fTHEM2 at the resolution of 1.80 Å, which displayed a similar scaffolding as hTHEM2. Second, functional studies demonstrated that fTHEM2 is capable of hydrolyzing palmitoyl-CoA in vitro. In addition, injection of morpholino against fTHEM2 at one-cell stage resulted in distorted early embryomore » development, including delayed cell division, retarded development and increased death rate. The above findings validated our hypothesis that fTHEM2 could serve as an ideal surrogate for studying the physiological functions of THEM2. - Highlights: • The crystal structure of recombinant fTHEM2 is presented. • fTHEM2 is capable of hydrolyzing palmitoyl-CoA. • The influence of fTHEM2 on early embryo development is demonstrated.« less

From Tusko to Titin: the role for comparative physiology in an era of molecular discovery.

PubMed

Lindstedt, S L; Nishikawa, K C

2015-06-15

As we approach the centenary of the term "comparative physiology," we reexamine its role in modern biology. Finding inspiration in Krogh's classic 1929 paper, we first look back to some timeless contributions to the field. The obvious and fascinating variation among animals is much more evident than is their shared physiological unity, which transcends both body size and specific adaptations. The "unity in diversity" reveals general patterns and principles of physiology that are invisible when examining only one species. Next, we examine selected contemporary contributions to comparative physiology, which provides the context in which reductionist experiments are best interpreted. We discuss the sometimes surprising insights provided by two comparative "athletes" (pronghorn and rattlesnakes), which demonstrate 1) animals are not isolated molecular mechanisms but highly integrated physiological machines, a single "rate-limiting" step may be exceptional; and 2) extremes in nature are rarely the result of novel mechanisms, but rather employ existing solutions in novel ways. Furthermore, rattlesnake tailshaker muscle effectively abolished the conventional view of incompatibility of simultaneous sustained anaerobic glycolysis and oxidative ATP production. We end this review by looking forward, much as Krogh did, to suggest that a comparative approach may best lend insights in unraveling how skeletal muscle stores and recovers mechanical energy when operating cyclically. We discuss and speculate on the role of the largest known protein, titin (the third muscle filament), as a dynamic spring capable of storing and recovering elastic recoil potential energy in skeletal muscle. Copyright © 2015 the American Physiological Society.

Monomeric Alpha-Synuclein Exerts a Physiological Role on Brain ATP Synthase

PubMed Central

Ludtmann, Marthe H.R.; Angelova, Plamena R.; Ninkina, Natalia N.; Gandhi, Sonia

2016-01-01

Misfolded α-synuclein is a key factor in the pathogenesis of Parkinson's disease (PD). However, knowledge about a physiological role for the native, unfolded α-synuclein is limited. Using brains of mice lacking α-, β-, and γ-synuclein, we report that extracellular monomeric α-synuclein enters neurons and localizes to mitochondria, interacts with ATP synthase subunit α, and modulates ATP synthase function. Using a combination of biochemical, live-cell imaging and mitochondrial respiration analysis, we found that brain mitochondria of α-, β-, and γ-synuclein knock-out mice are uncoupled, as characterized by increased mitochondrial respiration and reduced mitochondrial membrane potential. Furthermore, synuclein deficiency results in reduced ATP synthase efficiency and lower ATP levels. Exogenous application of low unfolded α-synuclein concentrations is able to increase the ATP synthase activity that rescues the mitochondrial phenotypes observed in synuclein deficiency. Overall, the data suggest that α-synuclein is a previously unrecognized physiological regulator of mitochondrial bioenergetics through its ability to interact with ATP synthase and increase its efficiency. This may be of particular importance in times of stress or PD mutations leading to energy depletion and neuronal cell toxicity. SIGNIFICANCE STATEMENT Misfolded α-synuclein aggregations in the form of Lewy bodies have been shown to be a pathological hallmark in histological staining of Parkinson's disease (PD) patient brains. It is known that misfolded α-synuclein is a key driver in PD pathogenesis, but the physiological role of unfolded monomeric α-synuclein remains unclear. Using neuronal cocultures and isolated brain mitochondria of α-, β-, and γ-synuclein knock-out mice and monomeric α-synuclein, this current study shows that α-synuclein in its unfolded monomeric form improves ATP synthase efficiency and mitochondrial function. The ability of monomeric α-synuclein to enhance

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

Coordination of physiological and structural traits in Amazon forest trees

NASA Astrophysics Data System (ADS)

Patiño, S.; Fyllas, N. M.; Baker, T. R.; Paiva, R.; Quesada, C. A.; Santos, A. J. B.; Schwarz, M.; Ter Steege, H.; Phillips, O. L.; Lloyd, J.

2012-02-01

Many plant traits covary in a non-random manner reflecting interdependencies associated with "ecological strategy" dimensions. To understand how plants integrate their structural and physiological investments, data on leaf and leaflet size and the ratio of leaf area to sapwood area (ΦLS) obtained for 1020 individual trees (encompassing 661 species) located in 52 tropical forest plots across the Amazon Basin were incorporated into an analysis utilising existing data on species maximum height (Hmax), seed size, leaf mass per unit area (MA), foliar nutrients and δ13C, and branch xylem density (ρx). Utilising a common principal components approach allowing eigenvalues to vary between two soil fertility dependent species groups, five taxonomically controlled trait dimensions were identified. The first involves primarily cations, foliar carbon and MA and is associated with differences in foliar construction costs. The second relates to some components of the classic "leaf economic spectrum", but with increased individual leaf areas and a higher ΦLS newly identified components for tropical tree species. The third relates primarily to increasing Hmax and hence variations in light acquisition strategy involving greater MA, reductions in ΦLS and less negative δ13C. Although these first three dimensions were more important for species from high fertility sites the final two dimensions were more important for low fertility species and were associated with variations linked to reproductive and shade tolerance strategies. Environmental conditions influenced structural traits with ρx of individual species decreasing with increased soil fertility and higher temperatures. This soil fertility response appears to be synchronised with increases in foliar nutrient concentrations and reductions in foliar [C]. Leaf and leaflet area and ΦLS were less responsive to the environment than ρx. Thus, although genetically determined foliar traits such as those associated with leaf

Marine Microbial Secondary Metabolites: Pathways, Evolution and Physiological Roles.

PubMed

Giordano, Daniela; Coppola, Daniela; Russo, Roberta; Denaro, Renata; Giuliano, Laura; Lauro, Federico M; di Prisco, Guido; Verde, Cinzia

2015-01-01

Microbes produce a huge array of secondary metabolites endowed with important ecological functions. These molecules, which can be catalogued as natural products, have long been exploited in medical fields as antibiotics, anticancer and anti-infective agents. Recent years have seen considerable advances in elucidating natural-product biosynthesis and many drugs used today are natural products or natural-product derivatives. The major contribution to recent knowledge came from application of genomics to secondary metabolism and was facilitated by all relevant genes being organised in a contiguous DNA segment known as gene cluster. Clustering of genes regulating biosynthesis in bacteria is virtually universal. Modular gene clusters can be mixed and matched during evolution to generate structural diversity in natural products. Biosynthesis of many natural products requires the participation of complex molecular machines known as polyketide synthases and non-ribosomal peptide synthetases. Discovery of new evolutionary links between the polyketide synthase and fatty acid synthase pathways may help to understand the selective advantages that led to evolution of secondary-metabolite biosynthesis within bacteria. Secondary metabolites confer selective advantages, either as antibiotics or by providing a chemical language that allows communication among species, with other organisms and their environment. Herewith, we discuss these aspects focusing on the most clinically relevant bioactive molecules, the thiotemplated modular systems that include polyketide synthases, non-ribosomal peptide synthetases and fatty acid synthases. We begin by describing the evolutionary and physiological role of marine natural products, their structural/functional features, mechanisms of action and biosynthesis, then turn to genomic and metagenomic approaches, highlighting how the growing body of information on microbial natural products can be used to address fundamental problems in

Understanding Protein Synthesis: A Role-Play Approach in Large Undergraduate Human Anatomy and Physiology Classes

ERIC Educational Resources Information Center

Sturges, Diana; Maurer, Trent W.; Cole, Oladipo

2009-01-01

This study investigated the effectiveness of role play in a large undergraduate science class. The targeted population consisted of 298 students enrolled in 2 sections of an undergraduate Human Anatomy and Physiology course taught by the same instructor. The section engaged in the role-play activity served as the study group, whereas the section…

The role of heart rate variability in sports physiology

PubMed Central

DONG, JIN-GUO

2016-01-01

Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology. PMID:27168768

The role of heart rate variability in sports physiology.

PubMed

Dong, Jin-Guo

2016-05-01

Heart rate variability (HRV) is a relevant marker reflecting cardiac modulation by sympathetic and vagal components of the autonomic nervous system (ANS). Although the clinical application of HRV is mainly associated with the prediction of sudden cardiac death and assessing cardiovascular and metabolic illness progression, recent observations have suggested its applicability to physical exercise training. HRV is becoming one of the most useful tools for tracking the time course of training adaptation/maladaptation of athletes and in setting the optimal training loads leading to improved performances. However, little is known regarding the role of HRV and the internal effects of physical exercise on an athlete, which may be useful in designing fitness programs ensuring sufficient training load that may correspond with the specific ability of the athlete. In this review, we offer a comprehensive assessment of investigations concerning the interrelation between HRV and ANS, and examine how the application of HRV to physical exercise may play a role in sports physiology.

Dynamics and Physiological Roles of Stochastic Firing Patterns Near Bifurcation Points

NASA Astrophysics Data System (ADS)

Jia, Bing; Gu, Huaguang

2017-06-01

Different stochastic neural firing patterns or rhythms that appeared near polarization or depolarization resting states were observed in biological experiments on three nervous systems, and closely matched those simulated near bifurcation points between stable equilibrium point and limit cycle in a theoretical model with noise. The distinct dynamics of spike trains and interspike interval histogram (ISIH) of these stochastic rhythms were identified and found to build a relationship to the coexisting behaviors or fixed firing frequency of four different types of bifurcations. Furthermore, noise evokes coherence resonances near bifurcation points and plays important roles in enhancing information. The stochastic rhythms corresponding to Hopf bifurcation points with fixed firing frequency exhibited stronger coherence degree and a sharper peak in the power spectrum of the spike trains than those corresponding to saddle-node bifurcation points without fixed firing frequency. Moreover, the stochastic firing patterns changed to a depolarization resting state as the extracellular potassium concentration increased for the injured nerve fiber related to pathological pain or static blood pressure level increased for aortic depressor nerve fiber, and firing frequency decreased, which were different from the physiological viewpoint that firing frequency increased with increasing pressure level or potassium concentration. This shows that rhythms or firing patterns can reflect pressure or ion concentration information related to pathological pain information. Our results present the dynamics of stochastic firing patterns near bifurcation points, which are helpful for the identification of both dynamics and physiological roles of complex neural firing patterns or rhythms, and the roles of noise.

Rice Physiology

Treesearch

P.A. Counce; Davidi R. Gealy; Shi-Jean Susana Sung

2002-01-01

Physiology occurs tn physical space through chemical reactions constrained by anatomy and morphology, yet guided by genetics. Physiology has been called the logic of life. Genes encode structural and fimcdonal proteins. These proteins are subsequently processed to produce enzymes that direct and govern the biomechanical processes involved in the physiology of the...

Rapid Sensitization of Physiological, Neuronal, and Locomotor Effects of Nicotine: Critical Role of Peripheral Drug Actions

PubMed Central

Lenoir, Magalie; Tang, Jeremy S.; Woods, Amina S.

2013-01-01

Repeated exposure to nicotine and other psychostimulant drugs produces persistent increases in their psychomotor and physiological effects (sensitization), a phenomenon related to the drugs' reinforcing properties and abuse potential. Here we examined the role of peripheral actions of nicotine in nicotine-induced sensitization of centrally mediated physiological parameters (brain, muscle, and skin temperatures), cortical and VTA EEG, neck EMG activity, and locomotion in freely moving rats. Repeated injections of intravenous nicotine (30 μg/kg) induced sensitization of the drug's effects on all these measures. In contrast, repeated injections of the peripherally acting analog of nicotine, nicotine pyrrolidine methiodide (nicotinePM, 30 μg/kg, i.v.) resulted in habituation (tolerance) of the same physiological, neuronal, and behavioral measures. However, after repeated nicotine exposure, acute nicotinePM injections induced nicotine-like physiological responses: powerful cortical and VTA EEG desynchronization, EMG activation, a large brain temperature increase, but weaker hyperlocomotion. Additionally, both the acute locomotor response to nicotine and nicotine-induced locomotor sensitization were attenuated by blockade of peripheral nicotinic receptors by hexamethonium (3 mg/kg, i.v.). These data suggest that the peripheral actions of nicotine, which precede its direct central actions, serve as a conditioned interoceptive cue capable of eliciting nicotine-like physiological and neural responses after repeated nicotine exposure. Thus, by providing a neural signal to the CNS that is repeatedly paired with the direct central effects of nicotine, the drug's peripheral actions play a critical role in the development of nicotine-induced physiological, neural, and behavioral sensitization. PMID:23761889

Rapid sensitization of physiological, neuronal, and locomotor effects of nicotine: critical role of peripheral drug actions.

PubMed

Lenoir, Magalie; Tang, Jeremy S; Woods, Amina S; Kiyatkin, Eugene A

2013-06-12

Repeated exposure to nicotine and other psychostimulant drugs produces persistent increases in their psychomotor and physiological effects (sensitization), a phenomenon related to the drugs' reinforcing properties and abuse potential. Here we examined the role of peripheral actions of nicotine in nicotine-induced sensitization of centrally mediated physiological parameters (brain, muscle, and skin temperatures), cortical and VTA EEG, neck EMG activity, and locomotion in freely moving rats. Repeated injections of intravenous nicotine (30 μg/kg) induced sensitization of the drug's effects on all these measures. In contrast, repeated injections of the peripherally acting analog of nicotine, nicotine pyrrolidine methiodide (nicotine(PM), 30 μg/kg, i.v.) resulted in habituation (tolerance) of the same physiological, neuronal, and behavioral measures. However, after repeated nicotine exposure, acute nicotine(PM) injections induced nicotine-like physiological responses: powerful cortical and VTA EEG desynchronization, EMG activation, a large brain temperature increase, but weaker hyperlocomotion. Additionally, both the acute locomotor response to nicotine and nicotine-induced locomotor sensitization were attenuated by blockade of peripheral nicotinic receptors by hexamethonium (3 mg/kg, i.v.). These data suggest that the peripheral actions of nicotine, which precede its direct central actions, serve as a conditioned interoceptive cue capable of eliciting nicotine-like physiological and neural responses after repeated nicotine exposure. Thus, by providing a neural signal to the CNS that is repeatedly paired with the direct central effects of nicotine, the drug's peripheral actions play a critical role in the development of nicotine-induced physiological, neural, and behavioral sensitization.

Comparative physiology of a central hardwood old-growth forest canopy and forest gap

Treesearch

A. R. Gillespie; J. Waterman; K. Saylors

1993-01-01

Concerns of poor oak regeneration, changing climate, biodiversity patterns, and carbon cycling in the Central Hardwoods have prompted ecological and physiological studies of old-growth forests and their role in maintaining the landscape. To examine the effects of old-growth canopy structure on the physiological productivity of overstory and understory species, we...

Physiology and role of irisin in glucose homeostasis

PubMed Central

Perakakis, Nikolaos; Triantafyllou, Georgios A.; Fernández-Real, José Manuel; Huh, Joo Young; Park, Kyung Hee; Seufert, Jochen; Mantzoros, Christos S.

2018-01-01

Irisin is a myokine that leads to increased energy expenditure by stimulating the ‘browning’ of white adipose tissue. In the first description of this hormone, increased levels of circulating irisin, which is cleaved from its precursor fibronectin type III domain-containing protein 5, were associated with improved glucose homeostasis by reducing insulin resistance. Consequently, several studies attempted to characterize the role of irisin in glucose regulation, but contradictory results have been reported, and even the existence of this hormone has been questioned. In this Review, we present the current knowledge on the physiology of irisin and its role in glucose homeostasis. We describe the mechanisms involved in the synthesis, secretion, circulation and regulation of irisin, and the controversies regarding the measurement of irisin. We also discuss the direct effects of irisin on glucose regulatory mechanisms in different organs, the indirect effects and interactions with other hormones, and the important open questions with regard to irisin in those organs. Finally, we present the results from animal interventional studies and from human clinical studies investigating the association of irisin with obesity, insulin resistance, type 2 diabetes mellitus and the metabolic syndrome. PMID:28211512

A novel role of thrombopoietin as a physiological modulator of coronary flow.

PubMed

Ramella, Roberta; Gallo, Maria Pia; Spatola, Tiziana; Lupia, Enrico; Alloatti, Giuseppe

2011-02-25

Thrombopoietin (TPO) is known for its ability to stimulate platelet production. However, little is currently known whether TPO plays a physiological function in the heart. The potential vasodilatory role of TPO was tested on the isolated rat heart. The expression of TPO receptor (c-mpl) and the TPO-dependent eNOS phosphorylation (P(Ser1179)) were studied on Cardiac-derived normal Human Micro Vascular Endothelial Cells (HMVEC-C) by Western blot analysis. While TPO (10-200 pg/mL) did not modify coronary flow (CF) under basal conditions, it reduced the coronary constriction caused by endothelin-1 (ET-1; 10nM) in a dose-dependent manner. This effect was blocked by both Wortmannin (100 nM) and L-NAME (100 nM); on HMVEC-C, TPO induced eNOS phosphorylation through a Wortmannin sensitive mechanism. Taken together, our data suggest a potential role of TPO as a physiological regulator of CF. By acting on specific receptors present on endothelial cells, TPO may induce PI3K/Akt-dependent eNOS phosphorylation and NO release. Copyright © 2011 Elsevier B.V. All rights reserved.

Differential roles of NADPH oxidases in vascular physiology and pathophysiology

PubMed Central

Amanso, Angelica M.; Griendling, Kathy K.

2012-01-01

Reactive oxygen species (ROS) are produced by all vascular cells and regulate the major physiological functions of the vasculature. Production and removal of ROS are tightly controlled and occur in discrete subcellular locations, allowing for specific, compartmentalized signaling. Among the many sources of ROS in the vessel wall, NADPH oxidases are implicated in physiological functions such as control of vasomotor tone, regulation of extracellular matrix and phenotypic modulation of vascular smooth muscle cells. They are involved in the response to injury, whether as an oxygen sensor during hypoxia, as a regulator of protein processing, as an angiogenic stimulus, or as a mechanism of wound healing. These enzymes have also been linked to processes leading to disease development, including migration, proliferation, hypertrophy, apoptosis and autophagy. As a result, NADPH oxidases participate in atherogenesis, systemic and pulmonary hypertension and diabetic vascular disease. The role of ROS in each of these processes and diseases is complex, and a more full understanding of the sources, targets, cell-specific responses and counterbalancing mechanisms is critical for the rational development of future therapeutics. PMID:22202108

The Physiological Role of Abscisic Acid in Eliciting Turion Morphogenesis.

PubMed Central

Smart, C. C.; Fleming, A. J.; Chaloupkova, K.; Hanke, D. E.

1995-01-01

The exogenous application of hormones has led to their implication in a number of processes within the plant. However, proof of their function in vivo depends on quantitative data demonstrating that the exogenous concentration used to elicit a response leads to tissue hormone levels within the physiological range. Such proof is often lacking in many investigations. We are using abscisic acid (ABA)-induced turion formation in Spirodela polyrrhiza L. to investigate the mechanism by which a hormone can trigger a morphogenic switch. In this paper, we demonstrate that the exogenous concentration of ABA used to induce turions leads to tissue concentrations of ABA within the physiological range, as quantified by both enzyme-linked immunosorbent assay and high-performance liquid chromatography/gas chromatography-electron capture detection analysis. These results are consistent with ABA having a physiological role in turion formation, and they provide an estimate of the changes in endogenous ABA concentration required if environmental effectors of turion formation (e.g. nitrate deficiency, cold) act via an increased level of ABA. In addition, we show that the (+)- and (-)-enantiomers of ABA are equally effective in inducing turions. Moreover, comparison of the ABA; levels attained after treatment with (+)-, (-)-, and ([plus or minus])-ABA and their effect on turion induction and comparison of the effectiveness of ABA on turion induction under different pH regimes suggest that ABA most likely interacts with a plasmalemma-located receptor system to induce turion formation. PMID:12228499

Gap junctions in cells of the immune system: structure, regulation and possible functional roles.

PubMed

Sáez, J C; Brañes, M C; Corvalán, L A; Eugenín, E A; González, H; Martínez, A D; Palisson, F

2000-04-01

Gap junction channels are sites of cytoplasmic communication between contacting cells. In vertebrates, they consist of protein subunits denoted connexins (Cxs) which are encoded by a gene family. According to their Cx composition, gap junction channels show different gating and permeability properties that define which ions and small molecules permeate them. Differences in Cx primary sequences suggest that channels composed of different Cxs are regulated differentially by intracellular pathways under specific physiological conditions. Functional roles of gap junction channels could be defined by the relative importance of permeant substances, resulting in coordination of electrical and/or metabolic cellular responses. Cells of the native and specific immune systems establish transient homo- and heterocellular contacts at various steps of the immune response. Morphological and functional studies reported during the last three decades have revealed that many intercellular contacts between cells in the immune response present gap junctions or "gap junction-like" structures. Partial characterization of the molecular composition of some of these plasma membrane structures and regulatory mechanisms that control them have been published recently. Studies designed to elucidate their physiological roles suggest that they might permit coordination of cellular events which favor the effective and timely response of the immune system.

Neuropeptide physiology in helminths.

PubMed

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

2010-01-01

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

Role of Regulators of G Protein Signaling Proteins in Bone Physiology and Pathophysiology

PubMed Central

Jules, Joel; Yang, Shuying; Chen, Wei; Li, Yi-Ping

2016-01-01

Regulators of G protein signaling (RGS) proteins enhance the intrinsic GTPase activity of α subunits of the heterotrimeric G protein complex of G protein-coupled receptors (GPCRs) and thereby inactivate signal transduction initiated by GPCRs. The RGS family consists of nearly 37 members with a conserved RGS homology domain which is critical for their GTPase accelerating activity. RGS proteins are expressed in most tissues, including heart, lung, brain, kidney, and bone and play essential roles in many physiological and pathological processes. In skeletal development and bone homeostasis as well as in many bone disorders, RGS proteins control the functions of various GPCRs, including the parathyroid hormone receptor type 1 and calcium-sensing receptor and also regulate various critical signaling pathways, such as Wnt and calcium oscillations. This chapter will discuss the current findings on the roles of RGS proteins in regulating signaling of key GPCRs in skeletal development and bone homeostasis. We also will examine the current updates of RGS proteins’ regulation of calcium oscillations in bone physiology and highlight the roles of RGS proteins in selected bone pathological disorders. Despite the recent advances in bone and mineral research, RGS proteins remain understudied in the skeletal system. Further understanding of the roles of RGS proteins in bone should not only provide great insights into the molecular basis of various bone diseases but also generate great therapeutic drug targets for many bone diseases. PMID:26123302

Role of Regulators of G Protein Signaling Proteins in Bone Physiology and Pathophysiology.

PubMed

Jules, Joel; Yang, Shuying; Chen, Wei; Li, Yi-Ping

2015-01-01

Regulators of G protein signaling (RGS) proteins enhance the intrinsic GTPase activity of α subunits of the heterotrimeric G protein complex of G protein-coupled receptors (GPCRs) and thereby inactivate signal transduction initiated by GPCRs. The RGS family consists of nearly 37 members with a conserved RGS homology domain which is critical for their GTPase accelerating activity. RGS proteins are expressed in most tissues, including heart, lung, brain, kidney, and bone and play essential roles in many physiological and pathological processes. In skeletal development and bone homeostasis as well as in many bone disorders, RGS proteins control the functions of various GPCRs, including the parathyroid hormone receptor type 1 and calcium-sensing receptor and also regulate various critical signaling pathways, such as Wnt and calcium oscillations. This chapter will discuss the current findings on the roles of RGS proteins in regulating signaling of key GPCRs in skeletal development and bone homeostasis. We also will examine the current updates of RGS proteins' regulation of calcium oscillations in bone physiology and highlight the roles of RGS proteins in selected bone pathological disorders. Despite the recent advances in bone and mineral research, RGS proteins remain understudied in the skeletal system. Further understanding of the roles of RGS proteins in bone should not only provide great insights into the molecular basis of various bone diseases but also generate great therapeutic drug targets for many bone diseases. © 2015 Elsevier Inc. All rights reserved.

Physiological Regulation of Stress in Referred Adolescents: The Role of the Parent-Adolescent Relationship

ERIC Educational Resources Information Center

Willemen, Agnes M.; Schuengel, Carlo; Koot, Hans M.

2009-01-01

Background: Psychopathology in youth appears to be linked to deficits in regulating affective responses to stressful situations. In children, high-quality parental support facilitates affect regulation. However, in adolescence, the role of parent-child interaction in the regulation of affect is unclear. This study examined physiological reactivity…

Cognitive flexibility and undergraduate physiology students: increasing advanced knowledge acquisition within an ill-structured domain.

PubMed

Rhodes, Ashley E; Rozell, Timothy G

2017-09-01

Cognitive flexibility is defined as the ability to assimilate previously learned information and concepts to generate novel solutions to new problems. This skill is crucial for success within ill-structured domains such as biology, physiology, and medicine, where many concepts are simultaneously required for understanding a complex problem, yet the problem consists of patterns or combinations of concepts that are not consistently used or needed across all examples. To succeed within ill-structured domains, a student must possess a certain level of cognitive flexibility: rigid thought processes and prepackaged informational retrieval schemes relying on rote memorization will not suffice. In this study, we assessed the cognitive flexibility of undergraduate physiology students using a validated instrument entitled Student's Approaches to Learning (SAL). The SAL evaluates how deeply and in what way information is processed, as well as the investment of time and mental energy that a student is willing to expend by measuring constructs such as elaboration and memorization. Our results indicate that students who rely primarily on memorization when learning new information have a smaller knowledge base about physiological concepts, as measured by a prior knowledge assessment and unit exams. However, students who rely primarily on elaboration when learning new information have a more well-developed knowledge base about physiological concepts, which is displayed by higher scores on a prior knowledge assessment and increased performance on unit exams. Thus students with increased elaboration skills possibly possess a higher level of cognitive flexibility and are more likely to succeed within ill-structured domains. Copyright © 2017 the American Physiological Society.

Pulp-dentin biology in restorative dentistry. Part 1: normal structure and physiology.

PubMed

Mjör, I A; Sveen, O B; Heyeraas, K J

2001-06-01

Considerable knowledge has accumulated over the years on the structure and function of the dental pulp and dentin. Some of this knowledge has important clinical implications. This review, which is the first of seven articles, will be limited to those parts of the normal structure and physiology of the pulp and dentin that have been shown to result in, or are likely lead to, tissue reactions associated with the clinical treatment of these tissues. Although certain normal structures will be highlighted in some detail, a basic knowledge of pulpal and dentinal development and structure is a prerequisite for an understanding of this text.

A Role for Cytoplasmic Structural Proteins in the Transport of Water and Salts in the Intestine

DTIC Science & Technology

1981-12-08

inic Structural Proteins in the Transport ot Water and Salts in the Intestine by Paula T. Beall., Ph.D. D)epartment of Physiol.ogy Baylor CotleP,(e of...Med(icine 1200 Moursund Houston, ’T’exas 77030 December 8, 1981 Reproduction in whole or in part is permitted for any purpose of the United States...Research N00014-81-K-0167 A Role for Cytoplasmic Structural Proteins in the .. :..... . .-. ..... TiTans~por’t of Wa• and Salts in ’tIeIntestine

NADPH–Cytochrome P450 Oxidoreductase: Roles in Physiology, Pharmacology, and Toxicology

PubMed Central

Ding, Xinxin; Wolf, C. Roland; Porter, Todd D.; Pandey, Amit V.; Zhang, Qing-Yu; Gu, Jun; Finn, Robert D.; Ronseaux, Sebastien; McLaughlin, Lesley A.; Henderson, Colin J.; Zou, Ling; Flück, Christa E.

2013-01-01

This is a report on a symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics and held at the Experimental Biology 2012 meeting in San Diego, California, on April 25, 2012. The symposium speakers summarized and critically evaluated our current understanding of the physiologic, pharmacological, and toxicological roles of NADPH–cytochrome P450 oxidoreductase (POR), a flavoprotein involved in electron transfer to microsomal cytochromes P450 (P450), cytochrome b5, squalene mono-oxygenase, and heme oxygenase. Considerable insight has been derived from the development and characterization of mouse models with conditional Por deletion in particular tissues or partial suppression of POR expression in all tissues. Additional mouse models with global or conditional hepatic deletion of cytochrome b5 are helping to clarify the P450 isoform- and substrate-specific influences of cytochrome b5 on P450 electron transfer and catalytic function. This symposium also considered studies using siRNA to suppress POR expression in a hepatoma cell–culture model to explore the basis of the hepatic lipidosis phenotype observed in mice with conditional deletion of Por in liver. The symposium concluded with a strong translational perspective, relating the basic science of human POR structure and function to the impacts of POR genetic variation on human drug and steroid metabolism. PMID:23086197

Optimal physiological structure of small neurons to guarantee stable information processing

NASA Astrophysics Data System (ADS)

Zeng, S. Y.; Zhang, Z. Z.; Wei, D. Q.; Luo, X. S.; Tang, W. Y.; Zeng, S. W.; Wang, R. F.

2013-02-01

Spike is the basic element for neuronal information processing and the spontaneous spiking frequency should be less than 1 Hz for stable information processing. If the neuronal membrane area is small, the frequency of neuronal spontaneous spiking caused by ion channel noise may be high. Therefore, it is important to suppress the deleterious spontaneous spiking of the small neurons. We find by simulation of stochastic neurons with Hodgkin-Huxley-type channels that the leakage system is critical and extremely efficient to suppress the spontaneous spiking and guarantee stable information processing of the small neurons. However, within the physiological limit the potassium system cannot do so. The suppression effect of the leakage system is super-exponential, but that of the potassium system is quasi-linear. With the minor physiological cost and the minimal consumption of metabolic energy, a slightly lower reversal potential and a relatively larger conductance of the leakage system give the optimal physiological structure to suppress the deleterious spontaneous spiking and guarantee stable information processing of small neurons, dendrites and axons.

The role of plant physiology in hydrology: looking backwards and forwards

NASA Astrophysics Data System (ADS)

Roberts, J.

2007-01-01

conservative? An important contribution both to the similar and low transpiration is the likely reduction of stomatal conductance of the foliage associated with increasing air humidity deficit. A greater response is usually found when initial conductances are highest. Also contributing to similarities in transpiration from forest stands would be a compensatory role of understories and that deficits in soil moisture may not come into play until severe soil water deficits occur. Physiological studies have been conducted in many locations overseas. The modest transpiration of tropical rainforest is intriguing - Why is tropical rainforest transpiration so low? In common with temperate trees the reduction of stomatal conductance of tropical trees in association with increasing air humidity deficit will limit transpiration. In addition the high leaf area index of tropical rainforest creates conditions in the lower canopy layers that mean transpiration from those layers is much reduced from what might be possible. As well as being used to quantify and understand transpiration, physiological techniques might be used to assess when plants require water. What is the first signal that plants need water? Studies on sugar cane in Mauritius indicated that leaf growth was the most sensitive measure. A look forward to the future suggests that there will be a continued need for physiological measurements particularly where other techniques more suited to extensive vegetation are not appropriate. There are many unresolved issues about water use from fragmented, heterogeneous vegetation and physiological approaches are best suited to these. The measurement of sap flow in individual stems will be an important methodology in the future but there are still methodological issues to resolve.

Structures and physiological roles of 13 integral lipids of bovine heart cytochrome c oxidase

PubMed Central

Shinzawa-Itoh, Kyoko; Aoyama, Hiroshi; Muramoto, Kazumasa; Terada, Hirohito; Kurauchi, Tsuyoshi; Tadehara, Yoshiki; Yamasaki, Akiko; Sugimura, Takashi; Kurono, Sadamu; Tsujimoto, Kazuo; Mizushima, Tsunehiro; Yamashita, Eiki; Tsukihara, Tomitake; Yoshikawa, Shinya

2007-01-01

All 13 lipids, including two cardiolipins, one phosphatidylcholine, three phosphatidylethanolamines, four phosphatidylglycerols and three triglycerides, were identified in a crystalline bovine heart cytochrome c oxidase (CcO) preparation. The chain lengths and unsaturated bond positions of the fatty acid moieties determined by mass spectrometry suggest that each lipid head group identifies its specific binding site within CcOs. The X-ray structure demonstrates that the flexibility of the fatty acid tails facilitates their effective space-filling functions and that the four phospholipids stabilize the CcO dimer. Binding of dicyclohexylcarbodiimide to the O2 transfer pathway of CcO causes two palmitate tails of phosphatidylglycerols to block the pathway, suggesting that the palmitates control the O2 transfer process.The phosphatidylglycerol with vaccenate (cis-Δ11-octadecenoate) was found in CcOs of bovine and Paracoccus denitrificans, the ancestor of mitochondrion, indicating that the vaccenate is conserved in bovine CcO in spite of the abundance of oleate (cis-Δ9-octadecenoate). The X-ray structure indicates that the protein moiety selects cis-vaccenate near the O2 transfer pathway against trans-vaccenate. These results suggest that vaccenate plays a critical role in the O2 transfer mechanism. PMID:17332748

The growing outer epidermal wall: design and physiological role of a composite structure.

PubMed

Kutschera, U

2008-04-01

The cells of growing plant organs secrete an extracellular fibrous composite (the primary wall) that allows the turgid protoplasts to expand irreversibly via wall-yielding events, which are regulated by processes within the cytoplasm. The role of the epidermis in the control of stem elongation is described with special reference to the outer epidermal wall (OEW), which forms a 'tensile skin'. The OEW is much thicker and less extensible than the walls of the inner tissues. Moreover, in the OEW the amount of cellulose per unit wall mass is considerably greater than in the inner tissues. Ultrastructural studies have shown that the expanding OEW is composed of a highly ordered internal and a diffuse outer half, with helicoidally organized cellulose microfibrils in the inner (load-bearing) region of this tension-stressed organ wall. The structural and mechanical backbone of the wall consists of helicoids, i.e. layers of parallel, inextensible cellulose microfibrils. These 'plywood laminates' contain crystalline 'cables' orientated in all directions with respect to the axis of elongation (isotropic material). Cessation of cell elongation is accompanied by a loss of order, i.e. the OEW is a dynamic structure. Helicoidally arranged extracellular polymers have also been found in certain bacteria, algae, fungi and animals. In the insect cuticle crystalline cutin nanofibrils form characteristic 'OEW-like' herringbone patterns. Theoretical considerations, in vitro studies and computer simulations suggest that extracellular biological helicoids form by directed self-assembly of the crystalline biopolymers. This spontaneous generation of complex design 'without an intelligent designer' evolved independently in the protective 'skin' of plants, animals and many other organisms.

Preparation of Single-cohort Colonies and Hormone Treatment of Worker Honeybees to Analyze Physiology Associated with Role and/or Endocrine System.

PubMed

Ueno, Takayuki; Kawasaki, Kiyoshi; Kubo, Takeo

2016-09-06

Honeybee workers are engaged in various tasks related to maintaining colony activity. The tasks of the workers change according to their age (age-related division of labor). Young workers are engaged in nursing the brood (nurse bees), while older workers are engaged in foraging for nectar and pollen (foragers). The physiology of the workers changes in association with this role shift. For example, the main function of the hypopharyngeal glands (HPGs) changes from the secretion of major royal jelly proteins (MRJPs) to the secretion of carbohydrate-metabolizing enzymes. Because worker tasks change as the workers age in typical colonies, it is difficult to discriminate the physiological changes that occur with aging from those that occur with the role shift. To study the physiological changes in worker tissues, including the HPGs, in association with the role shift, it would be useful to manipulate the honeybee colony population by preparing single-cohort colonies in which workers of almost the same age perform different tasks. Here we describe a detailed protocol for preparing single-cohort colonies for this analysis. Six to eight days after single-cohort colony preparation, precocious foragers that perform foraging tasks earlier than usual appear in the colony. Representative results indicated role-associated changes in HPG gene expression, suggesting role-associated HPG function. In addition to manipulating the colony population, analysis of the endocrine system is important for investigating role-associated physiology. Here, we also describe a detailed protocol for treating workers with 20-hydroxyecdysone (20E), an active form of ecdysone, and methoprene, a juvenile hormone analogue. The survival rate of treated bees was sufficient to examine gene expression in the HPGs. Gene expression changes were observed in response to 20E- and/or methoprene-treatment, suggesting that hormone treatments induce physiological changes of the HPGs. The protocol for hormone

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.

THE REGULATION ROLE OF CAROTID BODY PERIPHERAL CHEMORECEPTORS IN PHYSIOLOGICAL AND PATHOPHYSIOLOGICAL CONDITIONS.

PubMed

Lazovic, Biljana; Zlatkovic Svenda, Mirjana; Durmic, Tijana; Stajic, Zoran; Duric, Vesna; Zugic, Vladimir

2016-11-01

The major oxygen sensors in the human body are peripheral chemoreceptors. also known as interoreceptors- as connected with internal organs, located in the aortic arch and in the body of the common carotid artery. Chemoreceptor function under physiological conditions. Stimulation of peripheral chemoreceptors during enviromental hypoxia causes a reflex-mediated increased ventilation, followed by the increase of the muscle sympatic activity, aiming to maintain tissue oxygen homeostatis, as well as glucosae, homeostatis. Besides that, peripheral chemoreceptors interact with central chemoreceptors. responsible for carbon dioxide changes . and they are able to modulate each other. Chemoreceptor function in pathophysiological conditions. Investigations of respiratory function in many pathological processes, such as hypertension, obstructive sleep apnea, congestive heart failure and many other diseases that are presented with enhanced peripheral chemosensitivity and impaired functional sy mpatholysis ultimately determine the peripheral chemorcceptor role and significance of peripheral chemoreceptors in the process of those pathological conditions development. Considering this, the presumed influence of peripheral chemoreceptors is important in patients having the above mentioned pathology. The importance and the role of peripheral chemoreceptors in the course of the breathing control is still controversial, despite many scientific attempts to solve this problem. The main objective of this review is to give the latest data on the peripheral chemoreceptor role and to highlight the importance of peripheral chemoreceptors for maintaining of oxygen homeostasis in pateints with hypoxia caused by either physiological or pathological conditions.

Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential.

PubMed

Gardères, Johan; Bourguet-Kondracki, Marie-Lise; Hamer, Bojan; Batel, Renato; Schröder, Heinz C; Müller, Werner E G

2015-08-07

An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest.

Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential

PubMed Central

Gardères, Johan; Bourguet-Kondracki, Marie-Lise; Hamer, Bojan; Batel, Renato; Schröder, Heinz C.; Müller, Werner E. G.

2015-01-01

An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest. PMID:26262628

Interpreting the Possible Ecological Role(s) of Cyanotoxins: Compounds for Competitive Advantage and/or Physiological Aide?

PubMed Central

Holland, Aleicia; Kinnear, Susan

2013-01-01

To date, most research on freshwater cyanotoxin(s) has focused on understanding the dynamics of toxin production and decomposition, as well as evaluating the environmental conditions that trigger toxin production, all with the objective of informing management strategies and options for risk reduction. Comparatively few research studies have considered how this information can be used to understand the broader ecological role of cyanotoxin(s), and the possible applications of this knowledge to the management of toxic blooms. This paper explores the ecological, toxicological, and genetic evidence for cyanotoxin production in natural environments. The possible evolutionary advantages of toxin production are grouped into two main themes: That of “competitive advantage” or “physiological aide”. The first grouping illustrates how compounds produced by cyanobacteria may have originated from the need for a cellular defence mechanism, in response to grazing pressure and/or resource competition. The second grouping considers the contribution that secondary metabolites make to improved cellular physiology, through benefits to homeostasis, photosynthetic efficiencies, and accelerated growth rates. The discussion also includes other factors in the debate about possible evolutionary roles for toxins, such as different modes of exposures and effects on non-target (i.e., non-competitive) species. The paper demonstrates that complex and multiple factors are at play in driving evolutionary processes in aquatic environments. This information may provide a fresh perspective on managing toxic blooms, including the need to use a “systems approach” to understand how physico-chemical conditions, as well biological stressors, interact to trigger toxin production. PMID:23807545

Interpreting the possible ecological role(s) of cyanotoxins: compounds for competitive advantage and/or physiological aide?

PubMed

Holland, Aleicia; Kinnear, Susan

2013-06-27

To date, most research on freshwater cyanotoxin(s) has focused on understanding the dynamics of toxin production and decomposition, as well as evaluating the environmental conditions that trigger toxin production, all with the objective of informing management strategies and options for risk reduction. Comparatively few research studies have considered how this information can be used to understand the broader ecological role of cyanotoxin(s), and the possible applications of this knowledge to the management of toxic blooms. This paper explores the ecological, toxicological, and genetic evidence for cyanotoxin production in natural environments. The possible evolutionary advantages of toxin production are grouped into two main themes: That of "competitive advantage" or "physiological aide". The first grouping illustrates how compounds produced by cyanobacteria may have originated from the need for a cellular defence mechanism, in response to grazing pressure and/or resource competition. The second grouping considers the contribution that secondary metabolites make to improved cellular physiology, through benefits to homeostasis, photosynthetic efficiencies, and accelerated growth rates. The discussion also includes other factors in the debate about possible evolutionary roles for toxins, such as different modes of exposures and effects on non-target (i.e., non-competitive) species. The paper demonstrates that complex and multiple factors are at play in driving evolutionary processes in aquatic environments. This information may provide a fresh perspective on managing toxic blooms, including the need to use a "systems approach" to understand how physico-chemical conditions, as well biological stressors, interact to trigger toxin production.

The role of estrogen in pubertal skeletal physiology: epiphyseal maturation and mineralization of the skeleton.

PubMed

Frank, G R

1995-06-01

The year 1994 is likely to be remembered by many endocrinologists as the year in which dramatic new light was shed on the role played by estrogen in human skeletal physiology. It was in 1994 that two new syndromes were described, each representing a human model in which estrogen action was lacking. The first case was a female with an aromatase defect and a resultant inability to synthesize estrogen, and the second case was a man with an estrogen receptor gene defect that resulted in a non-functioning estrogen receptor and complete estrogen resistance. By examining the phenotypes of these two individuals, we were able, for the first time, to see what pubertal skeletal changes occur in the absence of estrogen action and directly extrapolate the role of estrogen in skeletal physiology. What has become abundantly clear is that it is estrogen and not androgen that is responsible for pubertal epiphyseal maturation and skeletal mineralization.

ADSA Foundation Scholar Award: A role for serotonin in lactation physiology-Where do we go from here?

PubMed

Hernandez, L L

2018-04-25

Lactation is a physiological event that is exclusive to mammals. Lactation evolved as a strategy to improve the survival of the young by providing them with the complete nutrition that is required for survival upon birth as well as maternal-offspring bonding. Typically, milk production by the dam matches the demand of the young. The dairy cow is a unique exception in which the discoveries and genetic selection related to lactation physiology have been applied and resulted in a dramatic increase in milk yield of dairy cows. Studies on the role of mammary-derived serotonin and the coordination of various aspects of milk production and maternal metabolism have revealed novel mechanisms by which milk production and maternal metabolism can be improved. Furthermore, the investigation into molecular and cellular mechanisms regulating mammary gland function has revealed the importance of epigenetics on mammary gland function. Understanding mammary gland function at the cellular and physiological levels will be important for improving mammary gland control of maternal metabolism during early lactation. The early lactation period is a critical time for a dairy cow as that is when she is most susceptible to disease and metabolic disorders that can lead to negative effects on her productive capacity and overall health. Our research in the area of serotonin physiology has illustrated the importance of serotonin on the regulation of lactation and maternal homeostasis. Future research in the area of lactation physiology should be targeted at improving maternal health and longevity in the herd through manipulation of the signals the mammary gland sends to coordinate maternal metabolism and synthesize milk. Specifically, we believe that serotonin will play a central role in understanding the communication between the mammary gland and the maternal physiology during lactation. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The Physiological Functions and Structural Determinants of Catalytic Bias in the [FeFe]-Hydrogenases CpI and CpII of Clostridium pasteurianum Strain W5.

PubMed

Therien, Jesse B; Artz, Jacob H; Poudel, Saroj; Hamilton, Trinity L; Liu, Zhenfeng; Noone, Seth M; Adams, Michael W W; King, Paul W; Bryant, Donald A; Boyd, Eric S; Peters, John W

2017-01-01

The first generation of biochemical studies of complex, iron-sulfur-cluster-containing [FeFe]-hydrogenases and Mo-nitrogenase were carried out on enzymes purified from Clostridium pasteurianum (strain W5). Previous studies suggested that two distinct [FeFe]-hydrogenases are expressed differentially under nitrogen-fixing and non-nitrogen-fixing conditions. As a result, the first characterized [FeFe]-hydrogenase (CpI) is presumed to have a primary role in central metabolism, recycling reduced electron carriers that accumulate during fermentation via proton reduction. A role for capturing reducing equivalents released as hydrogen during nitrogen fixation has been proposed for the second hydrogenase, CpII. Biochemical characterization of CpI and CpII indicated CpI has extremely high hydrogen production activity in comparison to CpII, while CpII has elevated hydrogen oxidation activity in comparison to CpI when assayed under the same conditions. This suggests that these enzymes have evolved a catalytic bias to support their respective physiological functions. Using the published genome of C. pasteurianum (strain W5) hydrogenase sequences were identified, including the already known [NiFe]-hydrogenase, CpI, and CpII sequences, and a third hydrogenase, CpIII was identified in the genome as well. Quantitative real-time PCR experiments were performed in order to analyze transcript abundance of the hydrogenases under diazotrophic and non-diazotrophic growth conditions. There is a markedly reduced level of CpI gene expression together with concomitant increases in CpII gene expression under nitrogen-fixing conditions. Structure-based analyses of the CpI and CpII sequences reveal variations in their catalytic sites that may contribute to their alternative physiological roles. This work demonstrates that the physiological roles of CpI and CpII are to evolve and to consume hydrogen, respectively, in concurrence with their catalytic activities in vitro , with CpII capturing

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

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

Chakraborti, Subhendu; Bahnson, Brian J.

2010-05-25

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

Palmitic Acid: Physiological Role, Metabolism and Nutritional Implications

PubMed Central

Carta, Gianfranca; Murru, Elisabetta; Banni, Sebastiano; Manca, Claudia

2017-01-01

Palmitic acid (PA) has been for long time negatively depicted for its putative detrimental health effects, shadowing its multiple crucial physiological activities. PA is the most common saturated fatty acid accounting for 20–30% of total fatty acids in the human body and can be provided in the diet or synthesized endogenously via de novo lipogenesis (DNL). PA tissue content seems to be controlled around a well-defined concentration, and changes in its intake do not influence significantly its tissue concentration because the exogenous source is counterbalanced by PA endogenous biosynthesis. Particular physiopathological conditions and nutritional factors may strongly induce DNL, resulting in increased tissue content of PA and disrupted homeostatic control of its tissue concentration. The tight homeostatic control of PA tissue concentration is likely related to its fundamental physiological role to guarantee membrane physical properties but also to consent protein palmitoylation, palmitoylethanolamide (PEA) biosynthesis, and in the lung an efficient surfactant activity. In order to maintain membrane phospholipids (PL) balance may be crucial an optimal intake of PA in a certain ratio with unsaturated fatty acids, especially PUFAs of both n-6 and n-3 families. However, in presence of other factors such as positive energy balance, excessive intake of carbohydrates (in particular mono and disaccharides), and a sedentary lifestyle, the mechanisms to maintain a steady state of PA concentration may be disrupted leading to an over accumulation of tissue PA resulting in dyslipidemia, hyperglycemia, increased ectopic fat accumulation and increased inflammatory tone via toll-like receptor 4. It is therefore likely that the controversial data on the association of dietary PA with detrimental health effects, may be related to an excessive imbalance of dietary PA/PUFA ratio which, in certain physiopathological conditions, and in presence of an enhanced DNL, may further

Influence of phosphorus availability on the community structure and physiology of cultured biofilms.

PubMed

Li, Shuangshuang; Wang, Chun; Qin, Hongjie; Li, Yinxia; Zheng, Jiaoli; Peng, Chengrong; Li, Dunhai

2016-04-01

Biofilms have important effects on nutrient cycling in aquatic ecosystems. However, publications about the community structure and functions under laboratory conditions are rare. This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator. The results showed that the biomass (Chl a) and photosynthesis of algae were inhibited under P-limitation conditions, while the phosphatase activity and P assimilation rate were promoted. The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability. Cyanobacteria were more competitive than other algae in biofilms, particularly when cultured under low P levels. A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01, 0.1 and 0.6 mg/L. However, the total N content, dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability. This may be attributed to the low respiration rate, high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low. The bacterial community structure differed over time, while there was little difference between the four treatments, which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability. Altogether, these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water. Copyright © 2015. Published by Elsevier B.V.

Molecular and functional diversity of yeast and fungal lipases: their role in biotechnology and cellular physiology.

PubMed

Gupta, Rani; Kumari, Arti; Syal, Poonam; Singh, Yogesh

2015-01-01

Lipase catalyzes hydrolysis of fats in lipid water interphase and perform variety of biotransformation reactions under micro aqueous conditions. The major sources include microbial lipases; among these yeast and fungal lipases are of special interest because they can carry out various stereoselective reactions. These lipases are highly diverse and are categorized into three classes on the basis of oxyanion hole: GX, GGGX and Y. The detailed phylogenetic analysis showed that GX family is more diverse than GGGX and Y family. Sequence and structural comparisons revealed that lipases are conserved only in the signature sequence region. Their characteristic structural determinants viz. lid, binding pocket and oxyanion hole are hotspots for mutagenesis. Few examples are cited in this review to highlight the multidisciplinary approaches for designing novel enzyme variants with improved thermo stability and substrate specificity. In addition, we present a brief account on biotechnological applications of lipases. Lipases have also gained attention as virulence factors, therefore, we surveyed the role of lipases in yeast physiology related to colonization, adhesion, biofilm formation and pathogenesis. The new genomic era has opened numerous possibilities to genetically manipulate lipases for food, fuel and pharmaceuticals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polyploidy and the relationship between leaf structure and function: implications for correlated evolution of anatomy, morphology, and physiology in Brassica.

PubMed

Baker, Robert L; Yarkhunova, Yulia; Vidal, Katherine; Ewers, Brent E; Weinig, Cynthia

2017-01-05

Polyploidy is well studied from a genetic and genomic perspective, but the morphological, anatomical, and physiological consequences of polyploidy remain relatively uncharacterized. Whether these potential changes bear on functional integration or are idiosyncratic remains an open question. Repeated allotetraploid events and multiple genomic combinations as well as overlapping targets of artificial selection make the Brassica triangle an excellent system for exploring variation in the connection between plant structure (anatomy and morphology) and function (physiology). We examine phenotypic integration among structural aspects of leaves including external morphology and internal anatomy with leaf-level physiology among several species of Brassica. We compare diploid and allotetraploid species to ascertain patterns of phenotypic correlations among structural and functional traits and test the hypothesis that allotetraploidy results in trait disintegration allowing for transgressive phenotypes and additional evolutionary and crop improvement potential. Among six Brassica species, we found significant effects of species and ploidy level for morphological, anatomical and physiological traits. We identified three suites of intercorrelated traits in both diploid parents and allotetraploids: Morphological traits (such as leaf area and perimeter) anatomic traits (including ab- and ad- axial epidermis) and aspects of physiology. In general, there were more correlations between structural and functional traits for allotetraploid hybrids than diploid parents. Parents and hybrids did not have any significant structure-function correlations in common. Of particular note, there were no significant correlations between morphological structure and physiological function in the diploid parents. Increased phenotypic integration in the allotetraploid hybrids may be due, in part, to increased trait ranges or simply different structure-function relationships. Genomic and chromosomal

Sensory Hair Cells: An Introduction to Structure and Physiology.

PubMed

McPherson, Duane R

2018-06-18

Sensory hair cells are specialized secondary sensory cells that mediate our senses of hearing, balance, linear acceleration, and angular acceleration (head rotation). In addition, hair cells in fish and amphibians mediate sensitivity to water movement through the lateral line system, and closely related electroreceptive cells mediate sensitivity to low-voltage electric fields in the aquatic environment of many fish species and several species of amphibian.Sensory hair cells share many structural and functional features across all vertebrate groups, while at the same time they are specialized for employment in a wide variety of sensory tasks. The complexity of hair cell structure is large, and the diversity of hair cell applications in sensory systems exceeds that seen for most, if not all, sensory cell types. The intent of this review is to summarize the more significant structural features and some of the more interesting and important physiological mechanisms that have been elucidated thus far. Outside vertebrates, hair cells are only known to exist in the coronal organ of tunicates. Electrical resonance, electromotility, and their exquisite mechanical sensitivity all contribute to the attractiveness of hair cells as a research subject.

Biochemical factors modulating female genital sexual arousal physiology.

PubMed

Traish, Abdulmaged M; Botchevar, Ella; Kim, Noel N

2010-09-01

Female genital sexual arousal responses are complex neurophysiological processes consisting of central and peripheral components that occur following sexual stimulation. The peripheral responses in sexual arousal include genital vasocongestion, engorgement and lubrication resulting from a surge of vaginal and clitoral blood flow. These hemodynamic events are mediated by a host of neurotransmitters and vasoactive agents. To discuss the role of various biochemical factors modulating female genital sexual arousal responses. A comprehensive literature review was conducted using the PubMed database and citations were selected, based on topical relevance, and examined for study methodology and major findings. Data from peer-reviewed publications. Adrenergic as well as non-adrenergic non-cholinergic neurotransmitters play an important role in regulating genital physiological responses by mediating vascular and non-vascular smooth muscle contractility. Vasoactive peptides and neuropeptides also modulate genital sexual responses by regulating vascular and non-vascular smooth muscle cells and epithelial function. The endocrine milieu, particularly sex steroid hormones, is critical in the maintenance of tissue structure and function. Reduced levels of estrogens and androgen are associated with dramatic alterations in genital tissue structure, including the nerve network, as well as the response to physiological modulators. Furthermore, estrogen and androgen deficiency is associated with reduced expression of sex steroid receptors and most importantly with attenuated genital blood flow and lubrication in response to pelvic nerve stimulation. This article provides an integrated framework describing the physiological and molecular basis of various pathophysiological conditions associated with female genital sexual arousal dysfunction. © 2010 International Society for Sexual Medicine.

From Phytocannabinoids to Cannabinoid Receptors and Endocannabinoids: Pleiotropic Physiological and Pathological Roles Through Complex Pharmacology.

PubMed

Ligresti, Alessia; De Petrocellis, Luciano; Di Marzo, Vincenzo

2016-10-01

Apart from having been used and misused for at least four millennia for, among others, recreational and medicinal purposes, the cannabis plant and its most peculiar chemical components, the plant cannabinoids (phytocannabinoids), have the merit to have led humanity to discover one of the most intriguing and pleiotropic endogenous signaling systems, the endocannabinoid system (ECS). This review article aims to describe and critically discuss, in the most comprehensive possible manner, the multifaceted aspects of 1) the pharmacology and potential impact on mammalian physiology of all major phytocannabinoids, and not only of the most famous one Δ(9)-tetrahydrocannabinol, and 2) the adaptive pro-homeostatic physiological, or maladaptive pathological, roles of the ECS in mammalian cells, tissues, and organs. In doing so, we have respected the chronological order of the milestones of the millennial route from medicinal/recreational cannabis to the ECS and beyond, as it is now clear that some of the early steps in this long path, which were originally neglected, are becoming important again. The emerging picture is rather complex, but still supports the belief that more important discoveries on human physiology, and new therapies, might come in the future from new knowledge in this field. Copyright © 2016 the American Physiological Society.

The role of silicon in physiology of the medicinal plant (Lonicera japonica L.) under salt stress

NASA Astrophysics Data System (ADS)

Gengmao, Zhao; Shihui, Li; Xing, Sun; Yizhou, Wang; Zipan, Chang

2015-08-01

Silicon(Si) is the only element which can enhance the resistance to multiple stresses. However, the role of silicon in medicinal plants under salt stress is not yet understood. This experiment was conducted to study the effects of silicon addition on the growth, osmotic adjustments, photosynthetic characteristics, chloroplast ultrastructure and Chlorogenic acid (CGA) production of Honeysuckle plant (Lonicera japonica L.) under salt-stressed conditions. Salinity exerted an adverse effect on the plant fresh weight and dry weight, whilst 0.5 g L-1 K2SiO3·nH2O addition obviously improved the plant growth. Although Na+ concentration in plant organs was drastically increased with increasing salinity, higher levels of K+/Na+ ratio was obtained after K2SiO3·nH2O addition. Salinity stress induced the destruction of the chloroplast envelope; however, K2SiO3·nH2O addition counteracted the adverse effect by salinity on the structure of the photosynthetic apparatus. K2SiO3·nH2O addition also enhanced the activities of superoxide dismutase and catalase. To sum up, exogenous Si plays a key role in enhancing its resistance to salt stresses in physiological base, thereby improving the growth and CGA production of Honeysuckle plant.

The elusive structural role of ubiquitinated histones.

PubMed

Moore, Susan C; Jason, Laure; Ausió, Juan

2002-01-01

It is increasingly apparent that histone posttranslational modifications are important in chromatin structure and dynamics. However, histone ubiquitination has received little attention. Histones H1, H3, H2A, and H2B can be ubiquitinated in vivo, but the most prevalent are uH2A and uH2B. The size of this modification suggests some sort of structural impact. Physiological observations suggest that ubiquitinated histones may have multiple functions and structural effects. Ubiquitinated histones have been correlated with transcriptionally active DNA, implying that it may prevent chromatin folding or help maintain an open conformation. Also, in some organisms during spermiogenesis, a process involving extensive chromatin remodeling, uH2A levels increase just prior to histone replacement by protamines. Determination of chromatin's structural changes resulting from histone ubiquitination is therefore important. Recent work using reconstituted nucleosomes and chromatin fibers containing uH2A indicate that in the absence of linker histones, ubiquitination has little structural impact. DNase I digests and analytical ultracentrifugation of reconstituted ubiquitinated nucleosomes show no structural differences. Solubility assays using reconstituted chromatin fibers in the presence of divalent ions demonstrate that uH2A fibers are slightly more prone to aggregation than controls, and analytical ultracentrifugation results with different MgCl2 and NaCl concentrations determined that chromatin folding is not affected by this modification. Additional work to assess possible synergistic affects with histone acetylation also precludes any structural implications. Protamine displacement experiments concluded that the presence of uH2A does not significantly affect the ability of the protamines to displace histones. In addition, uH2A does not interfere with histone H1 binding to the nucleosome. While work with uH2B remains insufficient to come to any definitive conclusions about its

An alternative physiological role for the EmhABC efflux pump in Pseudomonas fluorescens cLP6a

PubMed Central

2011-01-01

Background Efflux pumps belonging to the resistance-nodulation-division (RND) superfamily in bacteria are involved in antibiotic resistance and solvent tolerance but have an unknown physiological role. EmhABC, a RND-type efflux pump in Pseudomonas fluorescens strain cLP6a, extrudes hydrophobic antibiotics, dyes and polycyclic aromatic hydrocarbons including phenanthrene. The effects of physico-chemical factors such as temperature or antibiotics on the activity and expression of EmhABC were determined in order to deduce its physiological role(s) in strain cLP6a in comparison to the emhB disruptant strain, cLP6a-1. Results Efflux assays conducted with 14C-phenanthrene showed that EmhABC activity is affected by incubation temperature. Increased phenanthrene efflux was measured in cLP6a cells grown at 10°C and decreased efflux was observed at 35°C compared with cells grown at the optimum temperature of 28°C. Membrane fatty acids in cLP6a cells were substantially altered by changes in growth temperature and in the presence of tetracycline. Changed membrane fatty acids and increased membrane permeability were associated with ~30-fold increased expression of emhABC in cLP6a cells grown at 35°C, and with increased extracellular free fatty acids. Growth of P. fluorescens cLP6a at supra-optimal temperature was enhanced by the presence of EmhABC compared to strain cLP6a-1. Conclusions Combined, these observations suggest that the EmhABC efflux pump may be involved in the management of membrane stress effects such as those due to unfavourable incubation temperatures. Efflux of fatty acids replaced as a result of membrane damage or phospholipid turnover may be the primary physiological role of the EmhABC efflux pump in P. fluorescens cLP6a. PMID:22085438

The Role of Nature in Coping with Psycho-Physiological Stress: A Literature Review on Restorativeness

PubMed Central

Berto, Rita

2014-01-01

Physical settings can play a role in coping with stress; in particular experimental research has found strong evidence between exposure to natural environments and recovery from physiological stress and mental fatigue, giving support to both Stress Recovery Theory and Attention Restoration Theory. In fact, exposure to natural environments protects people against the impact of environmental stressors and offer physiological, emotional and attention restoration more so than urban environments. Natural places that allow the renewal of personal adaptive resources to meet the demands of everyday life are called restorative environments. Natural environments elicit greater calming responses than urban environments, and in relation to their vision there is a general reduction of physiological symptoms of stress. Exposure to natural scenes mediates the negative effects of stress reducing the negative mood state and above all enhancing positive emotions. Moreover, one can recover the decrease of cognitive performance associated with stress, especially reflected in attention tasks, through the salutary effect of viewing nature. Giving the many benefits of contact with nature, plans for urban environments should attend to restorativeness. PMID:25431444

The Physiological Functions and Structural Determinants of Catalytic Bias in the [FeFe]-Hydrogenases CpI and CpII of Clostridium pasteurianum Strain W5

DOE PAGES

Therien, Jesse B.; Artz, Jacob H.; Poudel, Saroj; ...

2017-07-12

Here, the first generation of biochemical studies of complex, iron-sulfur-cluster-containing [FeFe]-hydrogenases and Mo-nitrogenase were carried out on enzymes purified from Clostridium pasteurianum (strain W5). Previous studies suggested that two distinct [FeFe]-hydrogenases are expressed differentially under nitrogen-fixing and non-nitrogen-fixing conditions. As a result, the first characterized [FeFe]-hydrogenase (CpI) is presumed to have a primary role in central metabolism, recycling reduced electron carriers that accumulate during fermentation via proton reduction. A role for capturing reducing equivalents released as hydrogen during nitrogen fixation has been proposed for the second hydrogenase, CpII. Biochemical characterization of CpI and CpII indicated CpI has extremely high hydrogenmore » production activity in comparison to CpII, while CpII has elevated hydrogen oxidation activity in comparison to CpI when assayed under the same conditions. This suggests that these enzymes have evolved a catalytic bias to support their respective physiological functions. Using the published genome of C. pasteurianum (strain W5) hydrogenase sequences were identified, including the already known [NiFe]-hydrogenase, CpI, and CpII sequences, and a third hydrogenase, CpIII was identified in the genome as well. Quantitative real-time PCR experiments were performed in order to analyze transcript abundance of the hydrogenases under diazotrophic and non-diazotrophic growth conditions. There is a markedly reduced level of CpI gene expression together with concomitant increases in CpII gene expression under nitrogen-fixing conditions. Structure-based analyses of the CpI and CpII sequences reveal variations in their catalytic sites that may contribute to their alternative physiological roles. This work demonstrates that the physiological roles of CpI and CpII are to evolve and to consume hydrogen, respectively, in concurrence with their catalytic activities in vitro, with Cp

The Physiological Functions and Structural Determinants of Catalytic Bias in the [FeFe]-Hydrogenases CpI and CpII of Clostridium pasteurianum Strain W5

PubMed Central

Therien, Jesse B.; Artz, Jacob H.; Poudel, Saroj; Hamilton, Trinity L.; Liu, Zhenfeng; Noone, Seth M.; Adams, Michael W. W.; King, Paul W.; Bryant, Donald A.; Boyd, Eric S.; Peters, John W.

2017-01-01

The first generation of biochemical studies of complex, iron-sulfur-cluster-containing [FeFe]-hydrogenases and Mo-nitrogenase were carried out on enzymes purified from Clostridium pasteurianum (strain W5). Previous studies suggested that two distinct [FeFe]-hydrogenases are expressed differentially under nitrogen-fixing and non-nitrogen-fixing conditions. As a result, the first characterized [FeFe]-hydrogenase (CpI) is presumed to have a primary role in central metabolism, recycling reduced electron carriers that accumulate during fermentation via proton reduction. A role for capturing reducing equivalents released as hydrogen during nitrogen fixation has been proposed for the second hydrogenase, CpII. Biochemical characterization of CpI and CpII indicated CpI has extremely high hydrogen production activity in comparison to CpII, while CpII has elevated hydrogen oxidation activity in comparison to CpI when assayed under the same conditions. This suggests that these enzymes have evolved a catalytic bias to support their respective physiological functions. Using the published genome of C. pasteurianum (strain W5) hydrogenase sequences were identified, including the already known [NiFe]-hydrogenase, CpI, and CpII sequences, and a third hydrogenase, CpIII was identified in the genome as well. Quantitative real-time PCR experiments were performed in order to analyze transcript abundance of the hydrogenases under diazotrophic and non-diazotrophic growth conditions. There is a markedly reduced level of CpI gene expression together with concomitant increases in CpII gene expression under nitrogen-fixing conditions. Structure-based analyses of the CpI and CpII sequences reveal variations in their catalytic sites that may contribute to their alternative physiological roles. This work demonstrates that the physiological roles of CpI and CpII are to evolve and to consume hydrogen, respectively, in concurrence with their catalytic activities in vitro, with CpII capturing excess

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.

Effect of noisy stimulation on neurobiological sensitization systems and its role for normal and pathological physiology

NASA Astrophysics Data System (ADS)

Huber, Martin; Braun, Hans; Krieg, J.\\:Urgen-Christian

2004-03-01

Sensitization is discussed as an important phenomenon playing a role in normal physiology but also with respect to the initiation and progression of a variety of neuropsychiatric disorders such as epilepsia, substance-related disorders or recurrent affective disorders. The relevance to understand the dynamics of sensitization phenomena is emphasized by recent findings that even single stimulations can induce longlasting changes in biological systems. To address specific questions associated with the sensitization dynamics, we use a computational approach and develop simple but physiologically-plausible models. In the present study we examine the effect of noisy stimulation on sensitization development in the model. We consider sub- and suprathresold stimulations with varying noise intensities and determine as response measures the (i) absolute number of stimulus-induced sensitzations and (ii) the temporal relsation of stimulus-sensitization coupling. The findings indicate that stochastic effects including stochastic resonance might well contribute to the physiology of sensitization mechanisms under both nomal and pathological conditions.

Role of light wavelengths in synchronization of circadian physiology in songbirds.

PubMed

Yadav, G; Malik, S; Rani, S; Kumar, V

2015-03-01

This study investigated whether at identical duration and equal energy level birds presented with short (450nm; blue, B) and long (640nm; red, R) light wavelengths would differentially interpret them and exhibit wavelength-dependent circadian behavioral and physiological responses, despite the difference in their breeding latitudes. Temperate migratory blackheaded buntings (Emberiza melanocephala) and subtropical non-migratory Indian weaverbirds (Ploceus philippinus) initially entrained to 12h light:12h darkness (12L:12D; L=0.33μM/m(2)/s, D=0μM/m(2)/s) in two groups of each, groups 1 and 2, were subjected to constant light (LL, 0.33μM/m(2)/s), which rendered them arrhythmic in the activity behavior. They were then exposed for about two weeks each to 12B:12R and 12R:12B (group 1) or 12R:12B and 12B:12R (group 2) at 0.33μM/m(2)/s light energy level. Blue and red light periods were interpreted as the day and night, respectively, with activity and no-activity in non-migratory weaverbirds or activity and intense activity (Zugunruhe, migratory night restlessness) in the migratory buntings. Consistent with this, plasma melatonin levels under B:R, not R:B, light cycle were low and high in blue and red light periods, respectively. A similar diurnal pattern was absent in the cortisol levels, however. These results show an important role of light wavelengths in synchronization of the circadian clock governed behavior and physiology to the photoperiodic environment, and suggest that photoperiodic timing might be a conserved physiological adaptation in many more birds, regardless of the difference in breeding latitudes, than has been generally envisaged. Copyright © 2014 Elsevier Inc. All rights reserved.

Role of GABAA receptors in the physiology and pharmacology of sleep.

PubMed

Winsky-Sommerer, Raphaëlle

2009-05-01

Most sedative-hypnotics used in insomnia treatment target the gamma-aminobutyric acid (GABA)(A) receptors. A vast repertoire of GABA(A) receptor subtypes has been identified and displays specific electrophysiological and functional properties. GABA(A)-mediated inhibition traditionally refers to 'phasic' inhibition, arising from synaptic GABA(A) receptors which transiently inhibit neurons. However, there is growing evidence that peri- or extra-synaptic GABA(A) receptors are continuously activated by low GABA concentrations and mediate a 'tonic' conductance. This slower type of signaling appears to play a key role in controlling cell excitability. This review aims at summarizing recent knowledge on GABA transmission, including the emergence of tonic conductance, and highlighting the importance of GABA(A) receptor heterogeneity. The mechanism of action of sedative-hypnotic drugs and their effects on sleep and the electroencephalogram will be reported. Furthermore, studies using genetically engineered mice will be emphasized, providing insights into the role of GABA(A) receptors in mechanisms underlying physiological and pharmacological sleep. Finally, we will address the potential of GABA(A) receptor pharmacology for the treatment of insomnia.

Coordination of physiological and structural traits in Amazon forest trees

NASA Astrophysics Data System (ADS)

Patiño, S.; Fyllas, N. M.; Baker, T. R.; Paiva, R.; Quesada, C. A.; Santos, A. J. B.; Schwarz, M.; Ter Steege, H.; Phillips, O. L.; Lloyd, J.

2011-05-01

Many plant traits covary in a non-random manner reflecting interdependencies associated with "ecological strategy" dimensions. To understand how plants modulate their structural investments to best maintain and utilise their physiological capabilities, data on leaf and leaflet size and the ratio of leaf area to sapwood area (ΦLS) obtained for 1040 tree species located in 53 tropical forest plots across the Amazon Basin were incorporated into an analysis utilising existing data on species maximum height (Hmax), seed size, leaf mass per unit area (MA), foliar nutrients and δ13C and branch xylem density (ρx). Utilising a common principal components approach allowing eigenvalues to vary between two soil fertility dependent species groups, five genetically controlled trait dimensions were identified. The first involves primarily cations, foliar carbon and MA and is associated with differences in foliar construction costs. The second relates to the classic "leaf economic spectrum", but with increased individual leaf areas and a higher ΦLS newly identified components. The third relates primarily to increasing Hmax and hence variations in light acquisition strategy involving greater MA, reductions in ΦLS and less negative δ13C. Although these first three dimensions were more important for species from high fertility sites the final two dimensions were more important for low fertility species and were associated with variations linked to reproductive and shade tolerance strategies. Environmental conditions also influenced structural traits with ρx decreasing with increased soil fertility and decreasing with increased temperatures. This soil fertility response appears to be synchronised with increases in foliar nutrient concentrations and reductions in foliar [C]. Leaf and leaflet area and ΦLS were less responsive to the environment than ρx. Thus although genetically determined foliar traits such as those associated with leaf construction costs coordinate

Physiological roles of glucocorticoids during early embryonic development of the zebrafish (Danio rerio)

PubMed Central

Wilson, K S; Matrone, G; Livingstone, D E W; Al-Dujaili, E A S; Mullins, J J; Tucker, C S; Hadoke, P W F; Kenyon, C J; Denvir, M A

2013-01-01

While glucocorticoids (GCs) are known to be present in the zebrafish embryo, little is known about their physiological roles at this stage. We hypothesised that GCs play key roles in stress response, hatching and swim activity during early development. To test this, whole embryo cortisol (WEC) and corticosteroid-related genes were measured in embryos from 6 to 120 h post fertilisation (hpf) by enzyme linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Stress response was assessed by change in WEC following stirring, hypoxia or brief electrical impulses applied to the bathing water. The impact of pharmacological and molecular GC manipulation on the stress response, spontaneous hatching and swim activity at different stages of development was also assessed. WEC levels demonstrated a biphasic pattern during development with a decrease from 0 to 36 hpf followed by a progressive increase towards 120 hpf. This was accompanied by a significant and sustained increase in the expression of genes encoding cyp11b1 (GC biosynthesis), hsd11b2 (GC metabolism) and gr (GC receptor) from 48 to 120 hpf. Metyrapone (Met), an inhibitor of 11β-hydroxylase (encoded by cyp11b1), and cyp11b1 morpholino (Mo) knockdown significantly reduced basal and stress-induced WEC levels at 72 and 120 hpf but not at 24 hpf. Spontaneous hatching and swim activity were significantly affected by manipulation of GC action from approximately 48 hpf onwards. We have identified a number of key roles of GCs in zebrafish embryos contributing to adaptive physiological responses under adverse conditions. The ability to alter GC action in the zebrafish embryo also highlights its potential value for GC research. PMID:24167225

CLC Chloride Channels and Transporters: Structure, Function, Physiology, and Disease.

PubMed

Jentsch, Thomas J; Pusch, Michael

2018-07-01

CLC anion transporters are found in all phyla and form a gene family of eight members in mammals. Two CLC proteins, each of which completely contains an ion translocation parthway, assemble to homo- or heteromeric dimers that sometimes require accessory β-subunits for function. CLC proteins come in two flavors: anion channels and anion/proton exchangers. Structures of these two CLC protein classes are surprisingly similar. Extensive structure-function analysis identified residues involved in ion permeation, anion-proton coupling and gating and led to attractive biophysical models. In mammals, ClC-1, -2, -Ka/-Kb are plasma membrane Cl - channels, whereas ClC-3 through ClC-7 are 2Cl - /H + -exchangers in endolysosomal membranes. Biological roles of CLCs were mostly studied in mammals, but also in plants and model organisms like yeast and Caenorhabditis elegans. CLC Cl - channels have roles in the control of electrical excitability, extra- and intracellular ion homeostasis, and transepithelial transport, whereas anion/proton exchangers influence vesicular ion composition and impinge on endocytosis and lysosomal function. The surprisingly diverse roles of CLCs are highlighted by human and mouse disorders elicited by mutations in their genes. These pathologies include neurodegeneration, leukodystrophy, mental retardation, deafness, blindness, myotonia, hyperaldosteronism, renal salt loss, proteinuria, kidney stones, male infertility, and osteopetrosis. In this review, emphasis is laid on biophysical structure-function analysis and on the cell biological and organismal roles of mammalian CLCs and their role in disease.

Role of physiological levels of 4-hydroxynonenal on adipocyte biology: implications for obesity and metabolic syndrome.

PubMed

Dasuri, Kalavathi; Ebenezer, Philip; Fernandez-Kim, Sun Ok; Zhang, Le; Gao, Zhanguo; Bruce-Keller, Annadora J; Freeman, Linnea R; Keller, Jeffrey N

2013-01-01

Lipid peroxidation products such as 4-hydroxynonenal (HNE) are known to be increased in response to oxidative stress, and are known to cause dysfunction and pathology in a variety of tissues during periods of oxidative stress. The aim of the current study was to determine the chronic (repeated HNE exposure) and acute effects of physiological concentrations of HNE toward multiple aspects of adipocyte biology using differentiated 3T3-L1 adipocytes. Our studies demonstrate that acute and repeated exposure of adipocytes to physiological concentrations of HNE is sufficient to promote subsequent oxidative stress, impaired adipogenesis, alter the expression of adipokines, and increase lipolytic gene expression and subsequent increase in free fatty acid (FFA) release. These results provide an insight in to the role of HNE-induced oxidative stress in regulation of adipocyte differentiation and adipose dysfunction. Taken together, these data indicate a potential role for HNE promoting diverse effects toward adipocyte homeostasis and adipocyte differentiation, which may be important to the pathogenesis observed in obesity and metabolic syndrome.

Acclimation of isoprene emission and photosynthesis to growth temperature in hybrid aspen: resolving structural and physiological controls.

PubMed

Rasulov, Bahtijor; Bichele, Irina; Hüve, Katja; Vislap, Vivian; Niinemets, Ülo

2015-04-01

Acclimation of foliage to growth temperature involves both structural and physiological modifications, but the relative importance of these two mechanisms of acclimation is poorly known, especially for isoprene emission responses. We grew hybrid aspen (Populus tremula x P. tremuloides) under control (day/night temperature of 25/20 °C) and high temperature conditions (35/27 °C) to gain insight into the structural and physiological acclimation controls. Growth at high temperature resulted in larger and thinner leaves with smaller and more densely packed chloroplasts and with lower leaf dry mass per area (MA). High growth temperature also led to lower photosynthetic and respiration rates, isoprene emission rate and leaf pigment content and isoprene substrate dimethylallyl diphosphate pool size per unit area, but to greater stomatal conductance. However, all physiological characteristics were similar when expressed per unit dry mass, indicating that the area-based differences were primarily driven by MA. Acclimation to high temperature further increased heat stability of photosynthesis and increased activation energies for isoprene emission and isoprene synthase rate constant. This study demonstrates that temperature acclimation of photosynthetic and isoprene emission characteristics per unit leaf area were primarily driven by structural modifications, and we argue that future studies investigating acclimation to growth temperature must consider structural modifications. © 2014 John Wiley & Sons Ltd.

Role of the liver X receptors in skin physiology: Putative pharmacological targets in human diseases.

PubMed

Ouedraogo, Zangbéwendé Guy; Fouache, Allan; Trousson, Amalia; Baron, Silvère; Lobaccaro, Jean-Marc A

2017-10-01

Liver X receptors (LXRs) are members of the nuclear receptor superfamily that have been shown to regulate various physiological functions such as lipid metabolism and cholesterol homeostasis. Concordant reports have elicited the possibility to target them to cure many human diseases including arteriosclerosis, cancer, arthritis, and diabetes. The high relevance of modulating LXR activities to treat numerous skin diseases, mainly those with exacerbated inflammation processes, contrasts with the lack of approved therapeutic use. This review makes an assessment to sum up the findings regarding the physiological roles of LXRs in skin and help progress towards the therapeutic and safe management of their activities. It focuses on the possible pharmacological targeting of LXRs to cure or prevent selected skin diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of motor unit structure in defining function

NASA Technical Reports Server (NTRS)

Monti, R. J.; Roy, R. R.; Edgerton, V. R.

2001-01-01

Motor units, defined as a motoneuron and all of its associated muscle fibers, are the basic functional units of skeletal muscle. Their activity represents the final output of the central nervous system, and their role in motor control has been widely studied. However, there has been relatively little work focused on the mechanical significance of recruiting variable numbers of motor units during different motor tasks. This review focuses on factors ranging from molecular to macroanatomical components that influence the mechanical output of a motor unit in the context of the whole muscle. These factors range from the mechanical properties of different muscle fiber types to the unique morphology of the muscle fibers constituting a motor unit of a given type and to the arrangement of those motor unit fibers in three dimensions within the muscle. We suggest that as a result of the integration of multiple levels of structural and physiological levels of organization, unique mechanical properties of motor units are likely to emerge. Copyright 2001 John Wiley & Sons, Inc.

ROLE OF ANTHROPOGENIC AND ENVIRONMENTAL VARIABLE ON THE PHYSIOLOGICAL AND ECOLOGICAL RESPONSES OF OYSTERS IN SOUTHWEST FLORIDA ESTUARIES

EPA Science Inventory

The role of freshwater alterations and seasonal changes on the ecological and physiological responses of oysters were investigated in the Caloosahatchee River, Estero Bay and Faka-Union estuaries in SW Florida. Condition index, oyster density, and disease incidence of Perkinsus m...

Focus on Extracellular Vesicles: Physiological Role and Signalling Properties of Extracellular Membrane Vesicles

PubMed Central

Iraci, Nunzio; Leonardi, Tommaso; Gessler, Florian; Vega, Beatriz; Pluchino, Stefano

2016-01-01

Extracellular vesicles (EVs) are a heterogeneous population of secreted membrane vesicles, with distinct biogenesis routes, biophysical properties and different functions both in physiological conditions and in disease. The release of EVs is a widespread biological process, which is conserved across species. In recent years, numerous studies have demonstrated that several bioactive molecules are trafficked with(in) EVs, such as microRNAs, mRNAs, proteins and lipids. The understanding of their final impact on the biology of specific target cells remains matter of intense debate in the field. Also, EVs have attracted great interest as potential novel cell-free therapeutics. Here we describe the proposed physiological and pathological functions of EVs, with a particular focus on their molecular content. Also, we discuss the advances in the knowledge of the mechanisms regulating the secretion of EV-associated molecules and the specific pathways activated upon interaction with the target cell, highlighting the role of EVs in the context of the immune system and as mediators of the intercellular signalling in the brain. PMID:26861302

Bmi-1: At the crossroads of physiological and pathological biology

PubMed Central

Bhattacharya, Resham; Mustafi, Soumyajit Banerjee; Street, Mark; Dey, Anindya; Dwivedi, Shailendra Kumar Dhar

2015-01-01

Bmi-1 is a member of the Polycomb Repressor Complex1 that mediates gene silencing by regulating chromatin structure and is indispensable for self-renewal of both normal and cancer stem cells. Despite three decades of research that have elucidated the transcriptional regulation, post-translational modifications and functions of Bmi-1 in regulating the DNA damage response, cellular bioenergetics, and pathologies, the entire potential of a protein with such varied function remains to be realized. This review attempts to synthesize the current knowledge on Bmi-1 with an emphasis on its role in both normal physiology and cancer. Additionally, since cancer stem cells are emerging as a new paradigm for therapy resistance, the role of Bmi-1 in this perspective is also highlighted. The wide spectrum of malignancies that implicate Bmi-1 as a signature for stemness and oncogenesis also make it a suitable candidate for therapy. Nonetheless new approaches are vitally needed to further characterize physiological roles of Bmi-1 with the long-term goal of using Bmi-1 as a prognostic marker and a therapeutic target. PMID:26448339

Role of vitamin D in ovarian physiology and its implication in reproduction: a systematic review.

PubMed

Irani, Mohamad; Merhi, Zaher

2014-08-01

To report an update on the role of vitamin D (VD) in ovarian physiology with a focus on genes involved in steroidogenesis, follicular development, and ovarian reserve, as well as ovulatory dysfunction associated with polycystic ovary syndrome (PCOS), and ovarian response to assisted reproductive technology (ART). Systematic review. Not applicable. Human, animal, and cell culture models. Pubmed literature search. Granulosa cell function, serum antimüllerian hormone (AMH), AMH and its receptor gene expression, soluble receptor for advanced glycation end-products (sRAGE), PCOS parameters, and ART outcome. In human granulosa cells, VD alters AMH signaling, FSH sensitivity, and progesterone production and release, indicating a possible physiologic role for VD in ovarian follicular development and luteinization. In the serum, 25-hydroxyvitamin D (25OH-D) is positively correlated with AMH, and appropriate VD supplementation in VD-depleted women can suppress the seasonal changes that occur in serum AMH. In VD-deficient women with PCOS, VD supplementation lowers the abnormally elevated serum AMH levels, possibly indicating a mechanism by which VD improves folliculogenesis. The antiinflammatory sRAGE serum levels significantly increase in women with PCOS after VD replacement. Although follicular fluid 25OH-D correlates with IVF outcomes, there is a lack of data pertaining to the impact of VD supplementation on pregnancy rates following IVF. This review underscores the need for understanding the mechanistic actions of VD in ovarian physiology and the critical need for randomized trials to elucidate the impact of VD supplementation on controlled ovarian hyperstimulation/IVF outcome and ovulatory dysfunction associated with PCOS. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Cardiac Physiology of Aging: Extracellular Considerations.

PubMed

Horn, Margaux A

2015-07-01

Aging is a major risk factor for the development of cardiovascular disease, with the majority of affected patients being elderly. Progressive changes to myocardial structure and function occur with aging, often in concert with underlying pathologies. However, whether chronological aging results in a remodeled "aged substrate" has yet to be established. In addition to myocyte contractility, myocardial performance relies heavily on the cardiac extracellular matrix (ECM), the roles of which are as dynamic as they are significant; including providing structural integrity, assisting in force transmission throughout the cardiac cycle and acting as a signaling medium for communication between cells and the extracellular environment. In the healthy heart, ECM homeostasis must be maintained, and matrix deposition is in balance with degradation. Consequently, alterations to, or misregulation of the cardiac ECM has been shown to occur in both aging and in pathological remodeling with disease. Mounting evidence suggests that age-induced matrix remodeling may occur at the level of ECM control; including collagen synthesis, deposition, maturation, and degradation. Furthermore, experimental studies using aged animal models not only suggest that the aged heart may respond differently to insult than the young, but the identification of key players specific to remodeling with age may hold future therapeutic potential for the treatment of cardiac dysfunction in the elderly. This review will focus on the role of the cardiac interstitium in the physiology of the aging myocardium, with particular emphasis on the implications to age-related remodeling in disease. © 2015 American Physiological Society.

Endogenous Pyrogen Physiology.

ERIC Educational Resources Information Center

Beisel, William R.

1980-01-01

Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

A Physiologically Based, Multi-Scale Model of Skeletal Muscle Structure and Function

PubMed Central

Röhrle, O.; Davidson, J. B.; Pullan, A. J.

2012-01-01

Models of skeletal muscle can be classified as phenomenological or biophysical. Phenomenological models predict the muscle’s response to a specified input based on experimental measurements. Prominent phenomenological models are the Hill-type muscle models, which have been incorporated into rigid-body modeling frameworks, and three-dimensional continuum-mechanical models. Biophysically based models attempt to predict the muscle’s response as emerging from the underlying physiology of the system. In this contribution, the conventional biophysically based modeling methodology is extended to include several structural and functional characteristics of skeletal muscle. The result is a physiologically based, multi-scale skeletal muscle finite element model that is capable of representing detailed, geometrical descriptions of skeletal muscle fibers and their grouping. Together with a well-established model of motor-unit recruitment, the electro-physiological behavior of single muscle fibers within motor units is computed and linked to a continuum-mechanical constitutive law. The bridging between the cellular level and the organ level has been achieved via a multi-scale constitutive law and homogenization. The effect of homogenization has been investigated by varying the number of embedded skeletal muscle fibers and/or motor units and computing the resulting exerted muscle forces while applying the same excitatory input. All simulations were conducted using an anatomically realistic finite element model of the tibialis anterior muscle. Given the fact that the underlying electro-physiological cellular muscle model is capable of modeling metabolic fatigue effects such as potassium accumulation in the T-tubular space and inorganic phosphate build-up, the proposed framework provides a novel simulation-based way to investigate muscle behavior ranging from motor-unit recruitment to force generation and fatigue. PMID:22993509

[Role of some psycho-physiological factors on driving safety].

PubMed

Bergomi, M; Vivoli, G; Rovesti, S; Bussetti, P; Ferrari, A; Vivoli, R

2010-01-01

Within a research project on the role played by human factors on road accidents, the aim of the present study is to evaluate, in young adults, the relationships between driver behaviour and personality factors as well as to assess the neuroendocrine correlates of psychological and behavioural factors investigated. Another aim is to estimate in what measure the performance levels are affected by demographic, psychological and chronobiological variables. It has been found a positive relation between highway code violations, extroversion trait of personality and Sensation Seeking scores, so confirming that this component of personality can affect risky behaviour. Furthermore the subjects more oriented to morningness chronotype were found to be prone to adopt safe driving behaviour. Regarding the relations of the neuroendocrine parameters and driving behaviour a positive correlation was observed between dopamine levels and frequency of driving violations while a negative relationship was found between adrenaline levels and frequency of driving errors. In conclusion the identification of psycho-physiological variables related to driving risky behaviour might be a useful instrument to design traffic safety programs tailored to high risk subjects.

DigitalHuman (DH): An Integrative Mathematical Model ofHuman Physiology

NASA Technical Reports Server (NTRS)

Hester, Robert L.; Summers, Richard L.; lIescu, Radu; Esters, Joyee; Coleman, Thomas G.

2010-01-01

Mathematical models and simulation are important tools in discovering the key causal relationships governing physiological processes and improving medical intervention when physiological complexity is a central issue. We have developed a model of integrative human physiology called DigitalHuman (DH) consisting of -5000 variables modeling human physiology describing cardiovascular, renal, respiratory, endocrine, neural and metabolic physiology. Users can view time-dependent solutions and interactively introduce perturbations by altering numerical parameters to investigate new hypotheses. The variables, parameters and quantitative relationships as well as all other model details are described in XML text files. All aspects of the model, including the mathematical equations describing the physiological processes are written in XML open source, text-readable files. Model structure is based upon empirical data of physiological responses documented within the peer-reviewed literature. The model can be used to understand proposed physiological mechanisms and physiological interactions that may not be otherwise intUitively evident. Some of the current uses of this model include the analyses of renal control of blood pressure, the central role of the liver in creating and maintaining insulin resistance, and the mechanisms causing orthostatic hypotension in astronauts. Additionally the open source aspect of the modeling environment allows any investigator to add detailed descriptions of human physiology to test new concepts. The model accurately predicts both qualitative and more importantly quantitative changes in clinically and experimentally observed responses. DigitalHuman provides scientists a modeling environment to understand the complex interactions of integrative physiology. This research was supported by.NIH HL 51971, NSF EPSCoR, and NASA

Narrative review: the role of leptin in human physiology: emerging clinical applications.

PubMed

Kelesidis, Theodore; Kelesidis, Iosif; Chou, Sharon; Mantzoros, Christos S

2010-01-19

Leptin is a hormone secreted by adipose tissue in direct proportion to amount of body fat. The circulating leptin levels serve as a gauge of energy stores, thereby directing the regulation of energy homeostasis, neuroendocrine function, and metabolism. Persons with congenital deficiency are obese, and treatment with leptin results in dramatic weight loss through decreased food intake and possible increased energy expenditure. However, most obese persons are resistant to the weight-reducing effects of leptin. Recent studies suggest that leptin is physiologically more important as an indicator of energy deficiency, rather than energy excess, and may mediate adaptation by driving increased food intake and directing neuroendocrine function to converse energy, such as inducing hypothalamic hypogonadism to prevent fertilization. Current studies investigate the role of leptin in weight-loss management because persons who have recently lost weight have relative leptin deficiency that may drive them to regain weight. Leptin deficiency is also evident in patients with diet- or exercise-induced hypothalamic amenorrhea and lipoatrophy. Replacement of leptin in physiologic doses restores ovulatory menstruation in women with hypothalamic amenorrhea and improves metabolic dysfunction in patients with lipoatrophy, including lipoatrophy associated with HIV or highly active antiretroviral therapy. The applications of leptin continue to grow and will hopefully soon be used therapeutically.

Angiotensin-I converting enzyme (ACE): structure, biological roles, and molecular basis for chloride ion dependence.

PubMed

Masuyer, Geoffrey; Yates, Christopher J; Sturrock, Edward D; Acharya, K Ravi

2014-10-01

Somatic angiotensin-I converting enzyme (sACE) has an essential role in the regulation of blood pressure and electrolyte fluid homeostasis. It is a zinc protease that cleaves angiotensin-I (AngI), bradykinin, and a broad range of other signalling peptides. The enzyme activity is provided by two homologous domains (N- and C-), which display clear differences in substrate specificities and chloride activation. The presence of chloride ions in sACE and its unusual role in activity was identified early on in the characterisation of the enzyme. The molecular mechanisms of chloride activation have been investigated thoroughly through mutagenesis studies and shown to be substrate-dependent. Recent results from X-ray crystallography structural analysis have provided the basis for the intricate interactions between ACE, its substrate and chloride ions. Here we describe the role of chloride ions in human ACE and its physiological consequences. Insights into the chloride activation of the N- and C-domains could impact the design of improved domain-specific ACE inhibitors.

Physiological role of urothelial cancer-associated one long noncoding RNA in human skeletogenic cell differentiation.

PubMed

Ishikawa, Takanori; Nishida, Takashi; Ono, Mitsuaki; Takarada, Takeshi; Nguyen, Ha Thi; Kurihara, Shinnosuke; Furumatsu, Takayuki; Murase, Yurika; Takigawa, Masaharu; Oohashi, Toshitaka; Kamioka, Hiroshi; Kubota, Satoshi

2018-06-01

A vast number of long-noncoding RNAs (lncRNA) are found expressed in human cells, which RNAs have been developed along with human evolution. However, the physiological functions of these lncRNAs remain mostly unknown. In the present study, we for the first time uncovered the fact that one of such lncRNAs plays a significant role in the differentiation of chondrocytes and, possibly, of osteoblasts differentiated from mesenchymal stem cells, which cells eventually construct the human skeleton. The urothelial cancer-associated 1 (UCA1) lncRNA is known to be associated with several human malignancies. Firstly, we confirmed that UCA1 was expressed in normal human chondrocytes, as well as in a human chondrocytic cell line; whereas it was not detected in human bone marrow mesenchymal stem cells (hBMSCs). Of note, although UCA1 expression was undetectable in hBMSCs, it was markedly induced along with the differentiation toward chondrocytes, suggesting its critical role in chondrogenesis. Consistent with this finding, silencing of the UCA1 gene significantly repressed the expression of chondrogenic genes in human chondrocytic cells. UCA1 gene silencing and hyper-expression also had a significant impact on the osteoblastic phenotype in a human cell line. Finally, forced expression of UCA1 in a murine chondrocyte precursor, which did not possess a UCA1 gene, overdrove its differentiation into chondrocytes. These results indicate a physiological and important role of this lncRNA in the skeletal development of humans, who require more sustained endochondral ossification and osteogenesis than do smaller vertebrates. © 2017 Wiley Periodicals, Inc.

Cognitive Flexibility and Undergraduate Physiology Students: Increasing Advanced Knowledge Acquisition within an Ill-Structured Domain

ERIC Educational Resources Information Center

Rhodes, Ashley E.; Rozell, Timothy G.

2017-01-01

Cognitive flexibility is defined as the ability to assimilate previously learned information and concepts to generate novel solutions to new problems. This skill is crucial for success within ill-structured domains such as biology, physiology, and medicine, where many concepts are simultaneously required for understanding a complex problem, yet…

Role of Endogenous Sulfur Dioxide in Regulating Vascular Structural Remodeling in Hypertension

PubMed Central

Chen, Selena; Tang, Chaoshu

2016-01-01

Sulfur dioxide (SO2), an emerging gasotransmitter, was discovered to be endogenously generated in the cardiovascular system. Recently, the physiological effects of endogenous SO2 were confirmed. Vascular structural remodeling (VSR), an important pathological change in many cardiovascular diseases, plays a crucial role in the pathogenesis of the diseases. Here, the authors reviewed the research progress of endogenous SO2 in regulating VSR by searching the relevant data from PubMed and Medline. In spontaneously hypertensive rats (SHRs) and pulmonary hypertensive rats, SO2/aspartate aminotransferase (AAT) pathway was significantly altered. SO2 inhibited vascular smooth muscle cell (VSMC) proliferation, promoted apoptosis, inhibited the synthesis of extracellular collagen but promoted its degradation, and enhanced antioxidative capacity, thereby playing a significant role in attenuating VSR. However, the detailed mechanisms needed to be further explored. Further studies in this field would be important for the better understanding of the pathogenesis of systemic hypertension and pulmonary hypertension. Also, clinical trials are needed to demonstrate if SO2 would be a potential therapeutic target in cardiovascular diseases. PMID:27721913

Structures and functions of insect arylalkylamine N-acetyltransferase (iaaNAT); a key enzyme for physiological and behavioral switch in arthropods.

PubMed

Hiragaki, Susumu; Suzuki, Takeshi; Mohamed, Ahmed A M; Takeda, Makio

2015-01-01

The evolution of N-acetyltransfeases (NATs) seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT) has been extensively studied since it leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with invertebrates. NAT therefore has distinct functional implications in circadian function, as timezymes (aaNAT), and also xenobiotic reactions (arylamine NAT or simply NAT). NATs belong to a broader enzyme group, the GCN5-related N-acetyltransferase superfamily. Due to low sequence homology and a seemingly fast rate of structural differentiation, the nomenclature for NATs can be confusing. The advent of bioinformatics, however, has helped to classify this group of enzymes; vertebrates have two distinct subgroups, the timezyme type and the xenobiotic type, which has a wider substrate range including imidazolamine, pharmacological drugs, environmental toxicants and even histone. Insect aaNAT (iaaNAT) form their own clade in the phylogeny, distinct from vertebrate aaNATs. Arthropods are unique, since the phylum has exoskeleton in which quinones derived from N-acetylated monoamines function in coupling chitin and arthropodins. Monoamine oxidase (MAO) activity is limited in insects, but NAT-mediated degradation prevails. However, unexpectedly iaaNAT occurs not only among arthropods but also among basal deuterostomia, and is therefore more apomorphic. Our analyses illustrate that iaaNATs has unique physiological roles but at the same time it plays a role in a timezyme function, at least in photoperiodism. Photoperiodism has been considered as a function of circadian system but the detailed molecular mechanism is not well understood. We propose a molecular hypothesis for photoperiodism in Antheraea pernyi based on the transcription regulation of NAT interlocked by the circadian system

Composition and structure of the pericellular environment. Physiological function and chemical composition of pericellular proteoglycan (an evolutionary view).

PubMed

Scott, J E

1975-07-17

Connective tissue cells exist in a meshwork of insoluble fibres, the interstices of which are filled with soluble, high molecular mass, anionic material of a predominantly carbohydrate nature. The interactions of fibres with the interfibrillar material are central to the discussion of connective tissue physiology. As with all soluble polymers, the interfibrillar polyanion tends to "swell' and the tangled mass of chains offers considerable resistance to penetration by the large insoluble fibres. The consequent pressure to "inflate' the fibrous network is important in giving elasticity to cartilage, transparency to cornea, etc. Branched structures (of proteoglycans) and straight-chain forms (of hyaluronate) are compared for their ability to fulfil these functions. Apart from their physical ("non-specific') roles proteoglycans and glycosaminoglycans are able to interact physicochemically with, for example, collagen in ways which show considerable specificity, and which presumably are important in the laying down of the fibrous network as well as in maintaining its mechanical integrity. It is proposed that the role played by radiation, particularly as mediated via the hydrated electron (eaq) was dominant in the pre- and post-biotic evolution of pericellular environments.

The physiological functions of central nervous system pericytes and a potential role in pain

PubMed Central

Beazley-Long, Nicholas; Durrant, Alexandra M; Swift, Matthew N; Donaldson, Lucy F

2018-01-01

Central nervous system (CNS) pericytes regulate critical functions of the neurovascular unit in health and disease. CNS pericytes are an attractive pharmacological target for their position within the neurovasculature and for their role in neuroinflammation. Whether the function of CNS pericytes also affects pain states and nociceptive mechanisms is currently not understood. Could it be that pericytes hold the key to pain associated with CNS blood vessel dysfunction? This article reviews recent findings on the important physiological functions of CNS pericytes and highlights how these neurovascular functions could be linked to pain states. PMID:29623199

MBBS Student Perceptions about Physiology Subject Teaching and Objective Structured Practical Examination Based Formative Assessment for Improving Competencies

ERIC Educational Resources Information Center

Lakshmipathy, K.

2015-01-01

The objectives of the present study were to 1) assess student attitudes to physiology, 2) evaluate student opinions about the influence of an objective structured practical examination (OSPE) on competence, and 3) assess the validity and reliability of an indigenously designed feedback questionnaire. A structured questionnaire containing 16 item…

The UV-B Photoreceptor UVR8: From Structure to Physiology

PubMed Central

Jenkins, Gareth I.

2014-01-01

Low doses of UV-B light (280 to 315 nm) elicit photomorphogenic responses in plants that modify biochemical composition, photosynthetic competence, morphogenesis, and defense. UV RESISTANCE LOCUS8 (UVR8) mediates photomorphogenic responses to UV-B by regulating transcription of a set of target genes. UVR8 differs from other known photoreceptors in that it uses specific Trp amino acids instead of a prosthetic chromophore for light absorption during UV-B photoreception. Absorption of UV-B dissociates the UVR8 dimer into monomers, initiating signal transduction through interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1. However, much remains to be learned about the physiological role of UVR8 and its interaction with other signaling pathways, the molecular mechanism of UVR8 photoreception, how the UVR8 protein initiates signaling, how it is regulated, and how UVR8 regulates transcription of its target genes. PMID:24481075

Adrenal clocks and the role of adrenal hormones in the regulation of circadian physiology.

PubMed

Leliavski, Alexei; Dumbell, Rebecca; Ott, Volker; Oster, Henrik

2015-02-01

The mammalian circadian timing system consists of a master pacemaker in the suprachiasmatic nucleus (SCN) and subordinate clocks that disseminate time information to various central and peripheral tissues. While the function of the SCN in circadian rhythm regulation has been extensively studied, we still have limited understanding of how peripheral tissue clock function contributes to the regulation of physiological processes. The adrenal gland plays a special role in this context as adrenal hormones show strong circadian secretion rhythms affecting downstream physiological processes. At the same time, they have been shown to affect clock gene expression in various other tissues, thus mediating systemic entrainment to external zeitgebers and promoting internal circadian alignment. In this review, we discuss the function of circadian clocks in the adrenal gland, how they are reset by the SCN and may further relay time-of-day information to other tissues. Focusing on glucocorticoids, we conclude by outlining the impact of adrenal rhythm disruption on neuropsychiatric, metabolic, immune, and malignant disorders. © 2014 The Author(s).

A Trial of the Objective Structured Practical Examination in Physiology at Melaka Manipal Medical College, India

ERIC Educational Resources Information Center

Abraham, Reem Rachel; Raghavendra, Rao; Surekha, Kamath; Asha, Kamath

2009-01-01

A single examination does not fulfill all the functions of assessment. The present study was undertaken to determine the reliability and student satisfaction regarding the objective structured practical examination (OSPE) as a method of assessment of laboratory exercises in physiology before implementing it in the forthcoming university…

Impact of physiology, structure and BRDF in hyperspectral time series of a Citrus orchard

NASA Astrophysics Data System (ADS)

Stuckens, J.; Dzikiti, S.; Verstraeten, W. W.; Verreynne, J. S.; Swinnen, R.; Coppin, P.

2010-05-01

Monitoring of plant production systems using remote sensing requires an understanding of the mechanisms in which physiological and structural changes as well as the quality and direction of incident light alter the measured canopy reflectance. Due to the evergreen nature of Citrus, the benefits of year-round monitoring of spectral changes are counterweighted by more subtle changes and seasonal trends than in other perennials. This study presents the results of a 14 months field measurement campaign in a commercial Citrus sinensis ‘Midknight Valencia' orchard in Wellington, Western Cape Province, South-Africa. Hyperspectral data were collected of canopy and leaf reflectance (350 - 2500 nm) of 16 representative trees at monthly intervals and supplemented with local climatology, orchard management records, sap stream, water potential and leaf and soil nutrient analysis. The aim of this research is to translate spectral changes and trends at the leaf and at canopy levels into physiological processes such as plant nutrient and carbohydrate balances and stress responses. Specific research questions include the spectral detection of flowering (date of anthesis, flowering intensity), fruit drop, fruit number and coloration, vegetative flushes, leaf senescence and drop and pruning. Attention is paid to the detection and the impact of sunburn (photo-damage). In order to separate physiological and structural changes from changes caused by seasonal changes in solar elevation during measurement time (bidirectional reflectance) a normalization function is constructed using simulated and measured data. Additional research is done to up-scale measurements from tree level to orchard level, which includes the tree variability, the influence of soil and weeds and different amounts of shading.

Ghrelin, CCK, GLP-1, and PYY(3-36): Secretory Controls and Physiological Roles in Eating and Glycemia in Health, Obesity, and After RYGB.

PubMed

Steinert, Robert E; Feinle-Bisset, Christine; Asarian, Lori; Horowitz, Michael; Beglinger, Christoph; Geary, Nori

2017-01-01

The efficacy of Roux-en-Y gastric-bypass (RYGB) and other bariatric surgeries in the management of obesity and type 2 diabetes mellitus and novel developments in gastrointestinal (GI) endocrinology have renewed interest in the roles of GI hormones in the control of eating, meal-related glycemia, and obesity. Here we review the nutrient-sensing mechanisms that control the secretion of four of these hormones, ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide tyrosine tyrosine [PYY(3-36)], and their contributions to the controls of GI motor function, food intake, and meal-related increases in glycemia in healthy-weight and obese persons, as well as in RYGB patients. Their physiological roles as classical endocrine and as locally acting signals are discussed. Gastric emptying, the detection of specific digestive products by small intestinal enteroendocrine cells, and synergistic interactions among different GI loci all contribute to the secretion of ghrelin, CCK, GLP-1, and PYY(3-36). While CCK has been fully established as an endogenous endocrine control of eating in healthy-weight persons, the roles of all four hormones in eating in obese persons and following RYGB are uncertain. Similarly, only GLP-1 clearly contributes to the endocrine control of meal-related glycemia. It is likely that local signaling is involved in these hormones' actions, but methods to determine the physiological status of local signaling effects are lacking. Further research and fresh approaches are required to better understand ghrelin, CCK, GLP-1, and PYY(3-36) physiology; their roles in obesity and bariatric surgery; and their therapeutic potentials. Copyright © 2017 the American Physiological Society.

The Role of Gap Junction Channels During Physiologic and Pathologic Conditions of the Human Central Nervous System

PubMed Central

Basilio, Daniel; Sáez, Juan C.; Orellana, Juan A.; Raine, Cedric S.; Bukauskas, Feliksas; Bennett, Michael V. L.; Berman, Joan W.

2013-01-01

Gap junctions (GJs) are expressed in most cell types of the nervous system, including neuronal stem cells, neurons, astrocytes, oligodendrocytes, cells of the blood brain barrier (endothelial cells and astrocytes) and under inflammatory conditions in microglia/macrophages. GJs connect cells by the docking of two hemichannels, one from each cell with each hemichannel being formed by 6 proteins named connexins (Cx). Unapposed hemichannels (uHC) also can be open on the surface of the cells allowing the release of different intracellular factors to the extracellular space. GJs provide a mechanism of cell-to-cell communication between adjacent cells that enables the direct exchange of intracellular messengers, such as calcium, nucleotides, IP3, and diverse metabolites, as well as electrical signals that ultimately coordinate tissue homeostasis, proliferation, differentiation, metabolism, cell survival and death. Despite their essential functions in physiological conditions, relatively little is known about the role of GJs and uHC in human diseases, especially within the nervous system. The focus of this review is to summarize recent findings related to the role of GJs and uHC in physiologic and pathologic conditions of the central nervous system. PMID:22438035

The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice.

PubMed

Miyazawa, Masaki; Ishii, Takamasa; Yasuda, Kayo; Noda, Setsuko; Onouchi, Hiromi; Hartman, Philip S; Ishii, Naoaki

2009-01-01

Much attention has been focused on the mitochondrial superoxide anion (O2(-)), which is also a critical free radial produced by ionizing radiation. The specific role of the mitochondrial O2(-) on physiological aging in mammals is still unclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O2(-) is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O2(-)relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O2(-) production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O2(-) levels. Mitochondrial O2(-) production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O2(-) production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O2(-) production has high organ specificity, and oxidative damage by O2(-) from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O2(-) from mitochondria plays a core role in physiological aging.

GLIS1-3 transcription factors: critical roles in the regulation of multiple physiological processes and diseases.

PubMed

Jetten, Anton M

2018-05-19

Krüppel-like zinc finger proteins form one of the largest families of transcription factors. They function as key regulators of embryonic development and a wide range of other physiological processes, and are implicated in a variety of pathologies. GLI-similar 1-3 (GLIS1-3) constitute a subfamily of Krüppel-like zinc finger proteins that act either as activators or repressors of gene transcription. GLIS3 plays a critical role in the regulation of multiple biological processes and is a key regulator of pancreatic β cell generation and maturation, insulin gene expression, thyroid hormone biosynthesis, spermatogenesis, and the maintenance of normal kidney functions. Loss of GLIS3 function in humans and mice leads to the development of several pathologies, including neonatal diabetes and congenital hypothyroidism, polycystic kidney disease, and infertility. Single nucleotide polymorphisms in GLIS3 genes have been associated with increased risk of several diseases, including type 1 and type 2 diabetes, glaucoma, and neurological disorders. GLIS2 plays a critical role in the kidney and GLIS2 dysfunction leads to nephronophthisis, an end-stage, cystic renal disease. In addition, GLIS1-3 have regulatory functions in several stem/progenitor cell populations. GLIS1 and GLIS3 greatly enhance reprogramming efficiency of somatic cells into induced embryonic stem cells, while GLIS2 inhibits reprogramming. Recent studies have obtained substantial mechanistic insights into several physiological processes regulated by GLIS2 and GLIS3, while a little is still known about the physiological functions of GLIS1. The localization of some GLIS proteins to the primary cilium suggests that their activity may be regulated by a downstream primary cilium-associated signaling pathway. Insights into the upstream GLIS signaling pathway may provide opportunities for the development of new therapeutic strategies for diabetes, hypothyroidism, and other diseases.

[Nitric oxide pathway and female lower urinary tract. Physiological and pathophysiological role].

PubMed

Gamé, X; Rischmann, P; Arnal, J-F; Malavaud, B

2013-09-01

The aim was to review the literature on nitric oxide and female lower urinary tract. A literature review through the PubMed library until December, 31 2012 was carried out using the following keywords: lower urinary tract, bladder, urethra, nervous central system, innervation, female, women, nitric oxide, phosphodiesterase, bladder outlet obstruction, urinary incontinence, overactive bladder, urinary tract infection. Two nitric oxide synthase isoforms, the neuronal (nNOS) and the endothelial (eNOS), are constitutively expressed in the lower urinary tract. Nevertheless, nNOS is mainly expressed in the bladder neck and the urethra. In the bladder, NO modulates the afferent neurons activity. In pathological condition, inducible NOS expression induces an increase in detrusor contractility and bladder wall thickness and eNOS facilitates Escherichia coli bladder wall invasion inducing recurrent urinary tract infections. In the urethra, NO play a major role in smooth muscle cells relaxation. The NO pathway plays a major role in the female lower urinary tract physiology and physiopathology. While it acts mainly on bladder outlet, in pathological condition, it is involved in bladder dysfunction occurrence. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Estrogens in Male Physiology.

PubMed

Cooke, Paul S; Nanjappa, Manjunatha K; Ko, CheMyong; Prins, Gail S; Hess, Rex A

2017-07-01

Estrogens have historically been associated with female reproduction, but work over the last two decades established that estrogens and their main nuclear receptors (ESR1 and ESR2) and G protein-coupled estrogen receptor (GPER) also regulate male reproductive and nonreproductive organs. 17β-Estradiol (E2) is measureable in blood of men and males of other species, but in rete testis fluids, E2 reaches concentrations normally found only in females and in some species nanomolar concentrations of estrone sulfate are found in semen. Aromatase, which converts androgens to estrogens, is expressed in Leydig cells, seminiferous epithelium, and other male organs. Early studies showed E2 binding in numerous male tissues, and ESR1 and ESR2 each show unique distributions and actions in males. Exogenous estrogen treatment produced male reproductive pathologies in laboratory animals and men, especially during development, and studies with transgenic mice with compromised estrogen signaling demonstrated an E2 role in normal male physiology. Efferent ductules and epididymal functions are dependent on estrogen signaling through ESR1, whose loss impaired ion transport and water reabsorption, resulting in abnormal sperm. Loss of ESR1 or aromatase also produces effects on nonreproductive targets such as brain, adipose, skeletal muscle, bone, cardiovascular, and immune tissues. Expression of GPER is extensive in male tracts, suggesting a possible role for E2 signaling through this receptor in male reproduction. Recent evidence also indicates that membrane ESR1 has critical roles in male reproduction. Thus estrogens are important physiological regulators in males, and future studies may reveal additional roles for estrogen signaling in various target tissues. Copyright © 2017 the American Physiological Society.

Acclimation of isoprene emission and photosynthesis to growth temperature in hybrid aspen: resolving structural and physiological controls

PubMed Central

Rasulov, Bahtijor; Bichele, Irina; Hüve, Katja; Vislap, Vivian; Niinemets, Ülo

2018-01-01

Acclimation of foliage to growth temperature involves both structural and physiological modifications, but the relative importance of these two mechanisms of acclimation is poorly known, especially for isoprene emission responses. We grew hybrid aspen (Populus tremula x P. tremuloides) under control (day/night temperature of 25/20 °C) and high temperature conditions (35/27 °C) to gain insight into the structural and physiological acclimation controls. Growth at high temperature resulted in larger and thinner leaves with smaller and more densely packed chloroplasts and with lower leaf dry mass per area (MA). High growth temperature also led to lower photosynthetic and respiration rates, isoprene emission rate and leaf pigment content and isoprene substrate dimethylallyl diphosphate pool size per unit area, but to greater stomatal conductance. However, the declining characteristics were similar when expressed per unit dry mass, indicating that the area-based differences were primarily driven by MA. Acclimation to high temperature further increased heat stability of photosynthesis, and increased activation energies for isoprene emission and isoprene synthase rate constant. This study demonstrates that temperature acclimation of photosynthetic and isoprene emission characteristics per unit leaf area was primarily driven by structural modifications, and we argue that future studies investigating acclimation to growth temperature must consider structural modifications. PMID:25158785

Gender, gender roles, and anxiety: perceived confirmability of self report, behavioral avoidance, and physiological reactivity.

PubMed

Stoyanova, Milena; Hope, Debra A

2012-01-01

Despite the well-documented gender effect in anxiety, less is known about contributing factors to women's greater risk for anxiety and fears. The present study examined the relationship between gender, gender role orientation (i.e., expressivity/instrumentality) and fear of harmless insects (tarantula), using a multimodal approach of self-report measures, a Behavioral Approach Test (BAT), and physiological reactivity. Participants (144 college students; 67 women, 77 men) completed a questionnaire packet and then were instructed to approach a tarantula. We were unable to replicate Pierce and Kirkpatrick's (1992) findings that men underreport anxiety. Consistent with the literature, women in the study experienced greater anxiety and avoidance compared to men. However, men and women did not differ on physiological reactivity during the first 2 min of the BAT. The concordance across avoidance, anxiety and heart rate reactivity differed by gender, suggesting that men and women have different experiences when faced with a fearful object. Furthermore, instrumentality (masculinity) was negatively related to anticipatory anxiety for women but not for men. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structures and functions of insect arylalkylamine N-acetyltransferase (iaaNAT); a key enzyme for physiological and behavioral switch in arthropods

PubMed Central

Hiragaki, Susumu; Suzuki, Takeshi; Mohamed, Ahmed A. M.; Takeda, Makio

2015-01-01

The evolution of N-acetyltransfeases (NATs) seems complex. Vertebrate arylalkylamine N-acetyltransferase (aaNAT) has been extensively studied since it leads to the synthesis of melatonin, a multifunctional neurohormone prevalent in photoreceptor cells, and is known as a chemical token of the night. Melatonin also serves as a scavenger for reactive oxygen species. This is also true with invertebrates. NAT therefore has distinct functional implications in circadian function, as timezymes (aaNAT), and also xenobiotic reactions (arylamine NAT or simply NAT). NATs belong to a broader enzyme group, the GCN5-related N-acetyltransferase superfamily. Due to low sequence homology and a seemingly fast rate of structural differentiation, the nomenclature for NATs can be confusing. The advent of bioinformatics, however, has helped to classify this group of enzymes; vertebrates have two distinct subgroups, the timezyme type and the xenobiotic type, which has a wider substrate range including imidazolamine, pharmacological drugs, environmental toxicants and even histone. Insect aaNAT (iaaNAT) form their own clade in the phylogeny, distinct from vertebrate aaNATs. Arthropods are unique, since the phylum has exoskeleton in which quinones derived from N-acetylated monoamines function in coupling chitin and arthropodins. Monoamine oxidase (MAO) activity is limited in insects, but NAT-mediated degradation prevails. However, unexpectedly iaaNAT occurs not only among arthropods but also among basal deuterostomia, and is therefore more apomorphic. Our analyses illustrate that iaaNATs has unique physiological roles but at the same time it plays a role in a timezyme function, at least in photoperiodism. Photoperiodism has been considered as a function of circadian system but the detailed molecular mechanism is not well understood. We propose a molecular hypothesis for photoperiodism in Antheraea pernyi based on the transcription regulation of NAT interlocked by the circadian system

Investigations of Protein Structure and Function Using the Scientific Literature: An Assignment for an Undergraduate Cell Physiology Course

PubMed Central

Mulnix, Amy B.

2003-01-01

Undergraduate biology curricula are being modified to model and teach the activities of scientists better. The assignment described here, one that investigates protein structure and function, was designed for use in a sophomore-level cell physiology course at Earlham College. Students work in small groups to read and present in poster format on the content of a single research article reporting on the structure and/or function of a protein. Goals of the assignment include highlighting the interdependence of protein structure and function; asking students to review, integrate, and apply previously acquired knowledge; and helping students see protein structure/function in a context larger than cell physiology. The assignment also is designed to build skills in reading scientific literature, oral and written communication, and collaboration among peers. Assessment of student perceptions of the assignment in two separate offerings indicates that the project successfully achieves these goals. Data specifically show that students relied heavily on their peers to understand their article. The assignment was also shown to require students to read articles more carefully than previously. In addition, the data suggest that the assignment could be modified and used successfully in other courses and at other institutions. PMID:14673490

Investigations of protein structure and function using the scientific literature: an assignment for an undergraduate cell physiology course.

PubMed

Mulnix, Amy B

2003-01-01

Undergraduate biology curricula are being modified to model and teach the activities of scientists better. The assignment described here, one that investigates protein structure and function, was designed for use in a sophomore-level cell physiology course at Earlham College. Students work in small groups to read and present in poster format on the content of a single research article reporting on the structure and/or function of a protein. Goals of the assignment include highlighting the interdependence of protein structure and function; asking students to review, integrate, and apply previously acquired knowledge; and helping students see protein structure/function in a context larger than cell physiology. The assignment also is designed to build skills in reading scientific literature, oral and written communication, and collaboration among peers. Assessment of student perceptions of the assignment in two separate offerings indicates that the project successfully achieves these goals. Data specifically show that students relied heavily on their peers to understand their article. The assignment was also shown to require students to read articles more carefully than previously. In addition, the data suggest that the assignment could be modified and used successfully in other courses and at other institutions.

Computer support for physiological cell modelling using an ontology on cell physiology.

PubMed

Takao, Shimayoshi; Kazuhiro, Komurasaki; Akira, Amano; Takeshi, Iwashita; Masanori, Kanazawa; Tetsuya, Matsuda

2006-01-01

The development of electrophysiological whole cell models to support the understanding of biological mechanisms is increasing rapidly. Due to the complexity of biological systems, comprehensive cell models, which are composed of many imported sub-models of functional elements, can get quite complicated as well, making computer modification difficult. Here, we propose a computer support to enhance structural changes of cell models, employing the markup languages CellML and our original PMSML (physiological model structure markup language), in addition to a new ontology for cell physiological modelling. In particular, a method to make references from CellML files to the ontology and a method to assist manipulation of model structures using markup languages together with the ontology are reported. Using these methods three software utilities, including a graphical model editor, are implemented. Experimental results proved that these methods are effective for the modification of electrophysiological models.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles.

PubMed

Lombardi, Giovanni; Barbaro, Mosè; Locatelli, Massimo; Banfi, Giuseppe

2017-06-01

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.

The physiological determinants of drug-induced lysosomal stress resistance

PubMed Central

Woldemichael, Tehetina; Rosania, Gus R.

2017-01-01

Many weakly basic, lipophilic drugs accumulate in lysosomes and exert complex, pleiotropic effects on organelle structure and function. Thus, modeling how perturbations of lysosomal physiology affect the maintenance of lysosomal ion homeostasis is necessary to elucidate the key factors which determine the toxicological effects of lysosomotropic agents, in a cell-type dependent manner. Accordingly, a physiologically-based mathematical modeling and simulation approach was used to explore the dynamic, multi-parameter phenomenon of lysosomal stress. With this approach, parameters that are either directly involved in lysosomal ion transportation or lysosomal morphology were transiently altered to investigate their downstream effects on lysosomal physiology reflected by the changes they induce in lysosomal pH, chloride, and membrane potential. In addition, combinations of parameters were simultaneously altered to assess which parameter was most critical for recovery of normal lysosomal physiology. Lastly, to explore the relationship between organelle morphology and induced stress, we investigated the effects of parameters controlling organelle geometry on the restoration of normal lysosomal physiology following a transient perturbation. Collectively, our results indicate a key, interdependent role of V-ATPase number and membrane proton permeability in lysosomal stress tolerance. This suggests that the cell-type dependent regulation of V-ATPase subunit expression and turnover, together with the proton permeability properties of the lysosomal membrane, is critical to understand the differential sensitivity or resistance of different cell types to the toxic effects of lysosomotropic drugs. PMID:29117253

Potential role of retinoids in ovarian physiology and pathogenesis of polycystic ovary syndrome.

PubMed

Jiang, Yanwen; Li, Chunjin; Chen, Lu; Wang, Fengge; Zhou, Xu

2017-06-01

Retinoids (retinol and its derivatives) are required for maintaining vision, immunity, barrier function, reproduction, embryogenesis, cell proliferation and differentiation. Furthermore, retinoid signaling plays a key role in initiating meiosis of germ cells of the mammalian fetal ovary. Recently, studies indicated that precise retinoid level regulation in the ovary provides a molecular control of ovarian development, steroidogenesis and oocyte maturation. Besides, abnormal retinoid signaling may be involved in the pathogenesis of polycystic ovary syndrome (PCOS), one of the most common ovarian endocrinopathies in reproductive-aged women worldwide. This review primarily summarizes recent advancements made in investigating the action of retinoid signaling in ovarian physiology as well as the abnormal retinoid signaling in PCOS. Copyright © 2017. Published by Elsevier B.V.

A worldwide analysis of within-canopy variations in leaf structural, chemical and physiological traits across plant functional types

PubMed Central

Niinemets, Ülo; Keenan, Trevor F.; Hallik, Lea

2018-01-01

Summary Extensive within-canopy light gradients importantly affect photosynthetic productivity of leaves in different canopy positions and lead to light-dependent increases in foliage photosynthetic capacity per area (AA). However, the controls on AA variations by changes in underlying traits are poorly known. We constructed an unprecedented worldwide database including 831 within-canopy gradients with standardized light estimates for 304 species belonging to major vascular plant functional types, and analyzed within-canopy variations in 12 key foliage structural, chemical and physiological traits by quantitatively separating the contributions of different traits to photosynthetic acclimation. Although the light-dependent increase in AA is surprisingly similar in different plant functional types, they fundamentally differ in the share of the controls on AA by constituent traits. Species with high rates of canopy development and leaf turnover exhibiting highly dynamic light environments, actively change AA by nitrogen reallocation among and partitioning within leaves. In contrast, species with slow leaf turnover exhibit a passive AA acclimation response primarily determined by acclimation of leaf structure to growth light. This review emphasizes that different combinations of traits are responsible for within-canopy photosynthetic acclimation in different plant functional types and solves an old enigma of the role of mass- vs. area-based traits in vegetation acclimation. PMID:25318596

Physiology and pathophysiology of K(ATP) channels in the pancreas and cardiovascular system: a review.

PubMed

Seino, Susumu

2003-01-01

K(ATP) channels are present in pancreatic and extrapancreatic tissues such as heart and smooth muscle, and display diverse molecular composition. They contain two different structural subunits: an inwardly rectifying potassium channel subunit (Kir6.x) and a sulfonylurea receptor (SURX). Recent studies on genetically engineered Kir6.2 knockout mice have provided a better understanding of the physiological and pathophysiological roles of Kir6.2-containing K(ATP) channels. Kir6.2/SUR1 has a pivotal role in pancreatic insulin secretion. Kir6.2/SUR2A mediates the effects of K(ATP) channels openers on cardiac excitability and contractility and contributes to ischemic preconditioning. However, controversy remains on the physiological properties of the K(ATP) channels in vascular smooth muscle cells. Kir6.1 knockout mice exhibit sudden cardiac death due to cardiac ischemia, indicating that Kir6.1 rather than Kir6.2 is critical in the regulation of vascular tone. This article summarizes current understanding of the physiology and pathophysiology of Kir6.1- and Kir6.2-containing K(ATP) channels.

Physiological roles of pyruvate ferredoxin oxidoreductase and pyruvate formate-lyase in Thermoanaerobacterium saccharolyticum JW/SL-YS485

DOE PAGES

Zhou, Jilai; Olson, Daniel G.; Lanahan, Anthony A.; ...

2015-09-15

We report that Thermoanaerobacter saccharolyticum is a thermophilic microorganism that has been engineered to produce ethanol at high titer (30–70 g/L) and greater than 90 % theoretical yield. However, few genes involved in pyruvate to ethanol production pathway have been unambiguously identified. In T. saccharolyticum, the products of six putative pfor gene clusters and one pfl gene may be responsible for the conversion of pyruvate to acetyl-CoA. To gain insights into the physiological roles of PFOR and PFL, we studied the effect of deletions of several genes thought to encode these activities. We found that that pyruvate ferredoxin oxidoreductase enzymemore » (PFOR) is encoded by the pforA gene and plays a key role in pyruvate dissimilation. We further demonstrated that pyruvate formate-lyase activity (PFL) is encoded by the pfl gene. Although the pfl gene is normally expressed at low levels, it is crucial for biosynthesis in T. saccharolyticum. In pforA deletion strains, pfl expression increased and was able to partially compensate for the loss of PFOR activity. Deletion of both pforA and pfl resulted in a strain that required acetate and formate for growth and produced lactate as the primary fermentation product, achieving 88 % theoretical lactate yield. PFOR encoded by Tsac_0046 and PFL encoded by Tsac_0628 are only two routes for converting pyruvate to acetyl-CoA in T. saccharolyticum. The physiological role of PFOR is pyruvate dissimilation, whereas that of PFL is supplying C1 units for biosynthesis.« less

Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation

PubMed Central

Oka, Hisaki

2016-01-01

Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature. PMID:27173144

Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation

NASA Astrophysics Data System (ADS)

Oka, Hisaki

2016-05-01

Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature.

Role of an elliptical structure in photosynthetic energy transfer: Collaboration between quantum entanglement and thermal fluctuation.

PubMed

Oka, Hisaki

2016-05-13

Recent experiments have revealed that the light-harvesting complex 1 (LH1) in purple photosynthetic bacteria has an elliptical structure. Generally, symmetry lowering in a structure leads to a decrease in quantum effects (quantum coherence and entanglement), which have recently been considered to play a role in photosynthetic energy transfer, and hence, elliptical structure seems to work against efficient photosynthetic energy transfer. Here we analyse the effect of an elliptical structure on energy transfer in a purple photosynthetic bacterium and reveal that the elliptical distortion rather enhances energy transfer from peripheral LH2 to LH1 at room temperature. Numerical results show that quantum entanglement between LH1 and LH2 is formed over a wider range of high energy levels than would have been the case with circular LH1. Light energy absorbed by LH2 is thermally pumped via thermal fluctuation and is effectively transferred to LH1 through the entangled states at room temperature rather than at low temperature. This result indicates the possibility that photosynthetic systems adopt an elliptical structure to effectively utilise both quantum entanglement and thermal fluctuation at physiological temperature.

α-Tocopherol and Hippocampal Neural Plasticity in Physiological and Pathological Conditions

PubMed Central

Ambrogini, Patrizia; Betti, Michele; Galati, Claudia; Di Palma, Michael; Lattanzi, Davide; Savelli, David; Galli, Francesco; Cuppini, Riccardo; Minelli, Andrea

2016-01-01

Neuroplasticity is an “umbrella term” referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity. PMID:27983697

Phospholipases of Mineralization Competent Cells and Matrix Vesicles: Roles in Physiological and Pathological Mineralizations

PubMed Central

Mebarek, Saida; Abousalham, Abdelkarim; Magne, David; Do, Le Duy; Bandorowicz-Pikula, Joanna; Pikula, Slawomir; Buchet, René

2013-01-01

The present review aims to systematically and critically analyze the current knowledge on phospholipases and their role in physiological and pathological mineralization undertaken by mineralization competent cells. Cellular lipid metabolism plays an important role in biological mineralization. The physiological mechanisms of mineralization are likely to take place in tissues other than in bones and teeth under specific pathological conditions. For instance, vascular calcification in arteries of patients with renal failure, diabetes mellitus or atherosclerosis recapitulates the mechanisms of bone formation. Osteoporosis—a bone resorbing disease—and rheumatoid arthritis originating from the inflammation in the synovium are also affected by cellular lipid metabolism. The focus is on the lipid metabolism due to the effects of dietary lipids on bone health. These and other phenomena indicate that phospholipases may participate in bone remodelling as evidenced by their expression in smooth muscle cells, in bone forming osteoblasts, chondrocytes and in bone resorbing osteoclasts. Among various enzymes involved, phospholipases A1 or A2, phospholipase C, phospholipase D, autotaxin and sphingomyelinase are engaged in membrane lipid remodelling during early stages of mineralization and cell maturation in mineralization-competent cells. Numerous experimental evidences suggested that phospholipases exert their action at various stages of mineralization by affecting intracellular signaling and cell differentiation. The lipid metabolites—such as arachidonic acid, lysophospholipids, and sphingosine-1-phosphate are involved in cell signaling and inflammation reactions. Phospholipases are also important members of the cellular machinery engaged in matrix vesicle (MV) biogenesis and exocytosis. They may favour mineral formation inside MVs, may catalyse MV membrane breakdown necessary for the release of mineral deposits into extracellular matrix (ECM), or participate in

Triplet repeat RNA structure and its role as pathogenic agent and therapeutic target

PubMed Central

Krzyzosiak, Wlodzimierz J.; Sobczak, Krzysztof; Wojciechowska, Marzena; Fiszer, Agnieszka; Mykowska, Agnieszka; Kozlowski, Piotr

2012-01-01

This review presents detailed information about the structure of triplet repeat RNA and addresses the simple sequence repeats of normal and expanded lengths in the context of the physiological and pathogenic roles played in human cells. First, we discuss the occurrence and frequency of various trinucleotide repeats in transcripts and classify them according to the propensity to form RNA structures of different architectures and stabilities. We show that repeats capable of forming hairpin structures are overrepresented in exons, which implies that they may have important functions. We further describe long triplet repeat RNA as a pathogenic agent by presenting human neurological diseases caused by triplet repeat expansions in which mutant RNA gains a toxic function. Prominent examples of these diseases include myotonic dystrophy type 1 and fragile X-associated tremor ataxia syndrome, which are triggered by mutant CUG and CGG repeats, respectively. In addition, we discuss RNA-mediated pathogenesis in polyglutamine disorders such as Huntington's disease and spinocerebellar ataxia type 3, in which expanded CAG repeats may act as an auxiliary toxic agent. Finally, triplet repeat RNA is presented as a therapeutic target. We describe various concepts and approaches aimed at the selective inhibition of mutant transcript activity in experimental therapies developed for repeat-associated diseases. PMID:21908410

Physiological and molecular biochemical mechanisms of bile formation

PubMed Central

Reshetnyak, Vasiliy Ivanovich

2013-01-01

This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract. PMID:24259965

Focus on the emerging new fields of network physiology and network medicine

NASA Astrophysics Data System (ADS)

Ivanov, Plamen Ch; Liu, Kang K. L.; Bartsch, Ronny P.

2016-10-01

Despite the vast progress and achievements in systems biology and integrative physiology in the last decades, there is still a significant gap in understanding the mechanisms through which (i) genomic, proteomic and metabolic factors and signaling pathways impact vertical processes across cells, tissues and organs leading to the expression of different disease phenotypes and influence the functional and clinical associations between diseases, and (ii) how diverse physiological systems and organs coordinate their functions over a broad range of space and time scales and horizontally integrate to generate distinct physiologic states at the organism level. Two emerging fields, network medicine and network physiology, aim to address these fundamental questions. Novel concepts and approaches derived from recent advances in network theory, coupled dynamical systems, statistical and computational physics show promise to provide new insights into the complexity of physiological structure and function in health and disease, bridging the genetic and sub-cellular level with inter-cellular interactions and communications among integrated organ systems and sub-systems. These advances form first building blocks in the methodological formalism and theoretical framework necessary to address fundamental problems and challenges in physiology and medicine. This ‘focus on’ issue contains 26 articles representing state-of-the-art contributions covering diverse systems from the sub-cellular to the organism level where physicists have key role in laying the foundations of these new fields.

Bacterial Community Structure and Physiological State within an Industrial Phenol Bioremediation System

PubMed Central

Whiteley, Andrew S.; Bailey, Mark J.

2000-01-01

The structure of bacterial populations in specific compartments of an operational industrial phenol remediation system was assessed to examine bacterial community diversity, distribution, and physiological state with respect to the remediation of phenolic polluted wastewater. Rapid community fingerprinting by PCR-based denaturing gradient gel electrophoresis (DGGE) of 16S rDNA indicated highly structured bacterial communities residing in all nine compartments of the treatment plant and not exclusively within the Vitox biological reactor. Whole-cell targeting by fluorescent in situ hybridization with specific oligonucleotides (directed to the α, β and γ subclasses of the class Proteobacteria [α-, β-, and γ-Proteobacteria, respectively], the Cytophaga-Flavobacterium group, and the Pseudomonas group) tended to mirror gross changes in bacterial community composition when compared with DGGE community fingerprinting. At the whole-cell level, the treatment compartments were numerically dominated by cells assigned to the Cytophaga-Flavobacterium group and to the γ-Proteobacteria. The α subclass Proteobacteria were of low relative abundance throughout the treatment system whilst the β subclass of the Proteobacteria exhibited local dominance in several of the processing compartments. Quantitative image analyses of cellular fluorescence was used as an indicator of physiological state within the populations probed with rDNA. For cells hybridized with EUB338, the mean fluorescence per cell decreased with increasing phenolic concentration, indicating the strong influence of the primary pollutant upon cellular rRNA content. The γ subclass of the Proteobacteria had a ribosome content which correlated positively with total phenolics and thiocyanate. While members of the Cytophaga-Flavobacterium group were numerically dominant in the processing system, their abundance and ribosome content data for individual populations did not correlate with any of the measured chemical

The BCCT family of carriers: from physiology to crystal structure.

PubMed

Ziegler, Christine; Bremer, Erhard; Krämer, Reinhard

2010-10-01

Increases in the environmental osmolarity are key determinants for the growth of microorganisms. To ensure a physiologically acceptable level of cellular hydration and turgor at high osmolarity, many bacteria accumulate compatible solutes. Osmotically controlled uptake systems allow the scavenging of these compounds from scarce environmental sources as effective osmoprotectants. A number of these systems belong to the BCCT family (betaine-choline-carnitine-transporter), sodium- or proton-coupled transporters (e.g. BetP and BetT respectively) that are ubiquitous in microorganisms. The BCCT family also contains CaiT, an L-carnitine/γ-butyrobetaine antiporter that is not involved in osmotic stress responses. The glycine betaine transporter BetP from Corynebacterium glutamicum is a representative for osmoregulated symporters of the BCCT family and functions both as an osmosensor and osmoregulator. The crystal structure of BetP in an occluded conformation in complex with its substrate glycine betaine and two crystal structures of CaiT in an inward-facing open conformation in complex with L-carnitine and γ-butyrobetaine were reported recently. These structures and the wealth of biochemical data on the activity control of BetP in response to osmotic stress enable a correlation between the sensing of osmotic stress by a transporter protein with the ensuing regulation of transport activity. Molecular determinants governing the high-affinity binding of the compatible solutes by BetP and CaiT, the coupling in symporters and antiporters, and the osmoregulatory properties are discussed in detail for BetP and various BCCT carriers. © 2010 Blackwell Publishing Ltd.

Physiological enzymology: The next frontier in understanding protein structure and function at the cellular level.

PubMed

Lee, Irene; Berdis, Anthony J

2016-01-01

Historically, the study of proteins has relied heavily on characterizing the activity of a single purified protein isolated from other cellular components. This classic approach allowed scientists to unambiguously define the intrinsic kinetic and chemical properties of that protein. The ultimate hope was to extrapolate this information toward understanding how the enzyme or receptor behaves within its native cellular context. These types of detailed in vitro analyses were necessary to reduce the innate complexities of measuring the singular activity and biochemical properties of a specific enzyme without interference from other enzymes and potential competing substrates. However, recent developments in fields encompassing cell biology, molecular imaging, and chemical biology now provide the unique chemical tools and instrumentation to study protein structure, function, and regulation in their native cellular environment. These advancements provide the foundation for a new field, coined physiological enzymology, which quantifies the function and regulation of enzymes and proteins at the cellular level. In this Special Edition, we explore the area of Physiological Enzymology and Protein Function through a series of review articles that focus on the tools and techniques used to measure the cellular activity of proteins inside living cells. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Understanding protein synthesis: a role-play approach in large undergraduate human anatomy and physiology classes.

PubMed

Sturges, Diana; Maurer, Trent W; Cole, Oladipo

2009-06-01

This study investigated the effectiveness of role play in a large undergraduate science class. The targeted population consisted of 298 students enrolled in 2 sections of an undergraduate Human Anatomy and Physiology course taught by the same instructor. The section engaged in the role-play activity served as the study group, whereas the section presented with a traditional lecture served as the control group. A pretest/posttest assessment and a survey were administered to both sections and used in data analysis. In addition, overall test scores and item analysis were examined. The analysis revealed that participants in both groups improved significantly from pretest to posttest, but there were no significant differences between the groups in posttest scores. Neither group showed a significant change from posttest to the exam. However, there was a moderate positive effect on engagement and satisfaction survey questions from being in the study group (based on 255 total surveys returned by both groups). The role-play activity was at least as effective as the lecture in terms of student performance on the above-mentioned assessments. In addition, it proved successful in engaging students in the learning process and increasing their satisfaction.

The Role of Psychological and Physiological Factors in Decision Making under Risk and in a Dilemma

PubMed Central

Fooken, Jonas; Schaffner, Markus

2016-01-01

Different methods to elicit risk attitudes of individuals often provide differing results despite a common theory. Reasons for such inconsistencies may be the different influence of underlying factors in risk-taking decisions. In order to evaluate this conjecture, a better understanding of underlying factors across methods and decision contexts is desirable. In this paper we study the difference in result of two different risk elicitation methods by linking estimates of risk attitudes to gender, age, and personality traits, which have been shown to be related. We also investigate the role of these factors during decision-making in a dilemma situation. For these two decision contexts we also investigate the decision-maker's physiological state during the decision, measured by heart rate variability (HRV), which we use as an indicator of emotional involvement. We found that the two elicitation methods provide different individual risk attitude measures which is partly reflected in a different gender effect between the methods. Personality traits explain only relatively little in terms of driving risk attitudes and the difference between methods. We also found that risk taking and the physiological state are related for one of the methods, suggesting that more emotionally involved individuals are more risk averse in the experiment. Finally, we found evidence that personality traits are connected to whether individuals made a decision in the dilemma situation, but risk attitudes and the physiological state were not indicative for the ability to decide in this decision context. PMID:26834591

The different role of sex hormones on female cardiovascular physiology and function: not only oestrogens.

PubMed

Salerni, Sara; Di Francescomarino, Samanta; Cadeddu, Christian; Acquistapace, Flavio; Maffei, Silvia; Gallina, Sabina

2015-06-01

Human response to different physiologic stimuli and cardiovascular (CV) adaptation to various pathologies seem to be gender specific. Sex-steroid hormones have been postulated as the major contributors towards these sex-related differences. This review will discuss current evidence on gender differences in CV function and remodelling, and will present the different role of the principal sex-steroid hormones on female heart. Starting from a review of sex hormones synthesis, receptors and CV signalling, we will summarize the current knowledge concerning the role of sex hormones on the regulation of our daily activities throughout the life, via the modulation of autonomic nervous system, excitation-contraction coupling pathway and ion channels activity. Many unresolved questions remain even if oestrogen effects on myocardial remodelling and function have been extensively studied. So this work will focus attention also on the controversial and complex relationship existing between androgens, progesterone and female heart. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

Anthropometric and physiological predispositions for elite soccer.

PubMed

Reilly, T; Bangsbo, J; Franks, A

2000-09-01

This review is focused on anthropometric and physiological characteristics of soccer players with a view to establishing their roles within talent detection, identification and development programmes. Top-class soccer players have to adapt to the physical demands of the game, which are multifactorial. Players may not need to have an extraordinary capacity within any of the areas of physical performance but must possess a reasonably high level within all areas. This explains why there are marked individual differences in anthropometric and physiological characteristics among top players. Various measurements have been used to evaluate specific aspects of the physical performance of both youth and adult soccer players. The positional role of a player is related to his or her physiological capacity. Thus, midfield players and full-backs have the highest maximal oxygen intakes ( > 60 ml x kg(-1) x min(-1)) and perform best in intermittent exercise tests. On the other hand, midfield players tend to have the lowest muscle strength. Although these distinctions are evident in adult and elite youth players, their existence must be interpreted circumspectly in talent identification and development programmes. A range of relevant anthropometric and physiological factors can be considered which are subject to strong genetic influences (e.g. stature and maximal oxygen intake) or are largely environmentally determined and susceptible to training effects. Consequently, fitness profiling can generate a useful database against which talented groups may be compared. No single method allows for a representative assessment of a player's physical capabilities for soccer. We conclude that anthropometric and physiological criteria do have a role as part of a holistic monitoring of talented young players.

Specifications Physiological Monitoring System

NASA Technical Reports Server (NTRS)

1985-01-01

The operation of a physiological monitoring system (PMS) is described. Specifications were established for performance, design, interface, and test requirements. The PMS is a compact, microprocessor-based system, which can be worn in a pack on the body or may be mounted on a Spacelab rack or other appropriate structure. It consists of two modules, the Data Control Unit (DCU) and the Remote Control/Display Unit (RCDU). Its purpose is to collect and distribute data from physiological experiments in the Spacelab and in the Orbiter.

Physiological roles of zinc transporters: molecular and genetic importance in zinc homeostasis.

PubMed

Hara, Takafumi; Takeda, Taka-Aki; Takagishi, Teruhisa; Fukue, Kazuhisa; Kambe, Taiho; Fukada, Toshiyuki

2017-03-01

Zinc (Zn) is an essential trace mineral that regulates the expression and activation of biological molecules such as transcription factors, enzymes, adapters, channels, and growth factors, along with their receptors. Zn deficiency or excessive Zn absorption disrupts Zn homeostasis and affects growth, morphogenesis, and immune response, as well as neurosensory and endocrine functions. Zn levels must be adjusted properly to maintain the cellular processes and biological responses necessary for life. Zn transporters regulate Zn levels by controlling Zn influx and efflux between extracellular and intracellular compartments, thus, modulating the Zn concentration and distribution. Although the physiological functions of the Zn transporters remain to be clarified, there is growing evidence that Zn transporters are related to human diseases, and that Zn transporter-mediated Zn ion acts as a signaling factor, called "Zinc signal". Here we describe critical roles of Zn transporters in the body and their contribution at the molecular, biochemical, and genetic levels, and review recently reported disease-related mutations in the Zn transporter genes.

NF-κB signaling pathways: role in nervous system physiology and pathology.

PubMed

Mincheva-Tasheva, Stefka; Soler, Rosa M

2013-04-01

Intracellular pathways related to cell survival regulate neuronal physiology during development and neurodegenerative disorders. One of the pathways that have recently emerged with an important role in these processes is nuclear factor-κB (NF-κB). The activity of this pathway leads to the nuclear translocation of the NF-κB transcription factors and the regulation of anti-apoptotic gene expression. Different stimuli can activate the pathway through different intracellular cascades (canonical, non-canonical, and atypical), contributing to the translocation of specific dimers of the NF-κB transcription factors, and each of these dimers can regulate the transcription of different genes. Recent studies have shown that the activation of this pathway regulates opposite responses such as cell survival or neuronal degeneration. These apparent contradictory effects depend on conditions such as the pathway stimuli, the origin of the cells, or the cellular context. In the present review, the authors summarize these findings and discuss their significance with respect to survival or death in the nervous system.

Drug Sensitivity in Older Adults: The Role of Physiologic and Pharmacokinetic Factors.

ERIC Educational Resources Information Center

Cherry, Katie E.; Morton, Mark R.

1989-01-01

Notes that age-related changes in physiology and pharmacokinetics (how drugs are used in the body) lead to increased drug sensitivity and potentially harmful drug effects. Addresses heightened sensitivity to drug effects seen in older adults. Presents three examples of physiologic decline and discusses some broad considerations for geriatric…

Students' Motivation toward Laboratory Work in Physiology Teaching

ERIC Educational Resources Information Center

Dohn, Niels Bonderup; Fago, Angela; Overgaard, Johannes; Madsen, Peter Teglberg; Malte, Hans

2016-01-01

The laboratory has been given a central role in physiology education, and teachers report that it is motivating for students to undertake experimental work on live animals or measuring physiological responses on the students themselves. Since motivation is a critical variable for academic learning and achievement, then we must concern ourselves…

Acylcarnitines--old actors auditioning for new roles in metabolic physiology.

PubMed

McCoin, Colin S; Knotts, Trina A; Adams, Sean H

2015-10-01

Perturbations in metabolic pathways can cause substantial increases in plasma and tissue concentrations of long-chain acylcarnitines (LCACs). For example, the levels of LCACs and other acylcarnitines rise in the blood and muscle during exercise, as changes in tissue pools of acyl-coenzyme A reflect accelerated fuel flux that is incompletely coupled to mitochondrial energy demand and capacity of the tricarboxylic acid cycle. This natural ebb and flow of acylcarnitine generation and accumulation contrasts with that of inherited fatty acid oxidation disorders (FAODs), cardiac ischaemia or type 2 diabetes mellitus. These conditions are characterized by very high (FAODs, ischaemia) or modestly increased (type 2 diabetes mellitus) tissue and blood levels of LCACs. Although specific plasma concentrations of LCACs and chain-lengths are widely used as diagnostic markers of FAODs, research into the potential effects of excessive LCAC accumulation or the roles of acylcarnitines as physiological modulators of cell metabolism is lacking. Nevertheless, a growing body of evidence has highlighted possible effects of LCACs on disparate aspects of pathophysiology, such as cardiac ischaemia outcomes, insulin sensitivity and inflammation. This Review, therefore, aims to provide a theoretical framework for the potential consequences of tissue build-up of LCACs among individuals with metabolic disorders.

A worldwide analysis of within-canopy variations in leaf structural, chemical and physiological traits across plant functional types.

PubMed

Niinemets, Ülo; Keenan, Trevor F; Hallik, Lea

2015-02-01

Extensive within-canopy light gradients importantly affect the photosynthetic productivity of leaves in different canopy positions and lead to light-dependent increases in foliage photosynthetic capacity per area (AA). However, the controls on AA variations by changes in underlying traits are poorly known. We constructed an unprecedented worldwide database including 831 within-canopy gradients with standardized light estimates for 304 species belonging to major vascular plant functional types, and analyzed within-canopy variations in 12 key foliage structural, chemical and physiological traits by quantitative separation of the contributions of different traits to photosynthetic acclimation. Although the light-dependent increase in AA is surprisingly similar in different plant functional types, they differ fundamentally in the share of the controls on AA by constituent traits. Species with high rates of canopy development and leaf turnover, exhibiting highly dynamic light environments, actively change AA by nitrogen reallocation among and partitioning within leaves. By contrast, species with slow leaf turnover exhibit a passive AA acclimation response, primarily determined by the acclimation of leaf structure to growth light. This review emphasizes that different combinations of traits are responsible for within-canopy photosynthetic acclimation in different plant functional types, and solves an old enigma of the role of mass- vs area-based traits in vegetation acclimation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Tissue Physiology and Pathology of Aromatase

PubMed Central

Stocco, Carlos

2011-01-01

Summary Aromatase is expressed in multiple tissues, indicating a crucial role for locally produced oestrogens in the differentiation, regulation and normal function of several organs and processes. This review is an overview of the role of aromatase in different tissues under normal physiological conditions and its contribution to the development of some oestrogen-related pathologies. PMID:22108547

Centrifuges in gravitational physiology research

NASA Technical Reports Server (NTRS)

Ballard, Rodney W.; Davies, Phil; Fuller, Charles A.

1993-01-01

Data from space flight and ground based experiments have clearly demonstrated the importance of Earth gravity for normal physiological function in man and animals. Gravitational Physiology is concerned with the role and influence of gravity on physiological systems. Research in this field examines how we perceive and respond to gravity and the mechanisms underlying these responses. Inherent in our search for answers to these questions is the ability to alter gravity, which is not physically possible without leaving Earth. However, useful experimental paradigms have been to modify the perceived force of gravity by changing either the orientation of subjects to the gravity vector (i.e., postural changes) or by applying inertial forces to augment the magnitude of the gravity vector. The later technique has commonly been used by applying centripetal force via centrifugation.

Untangling the roles of microclimate, behaviour and physiological polymorphism in governing vulnerability of intertidal snails to heat stress.

PubMed

Dong, Yun-Wei; Li, Xiao-Xu; Choi, Francis M P; Williams, Gray A; Somero, George N; Helmuth, Brian

2017-05-17

Biogeographic distributions are driven by cumulative effects of smaller scale processes. Thus, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature ( T b ), microclimatic conditions, and behavioural thermoregulation. To understand interactions among these variables, we analysed the thermal tolerances of three species of intertidal snails from different latitudes along the Chinese coast, and estimated potential T b in different microhabitats at each site. We then empirically determined the temperatures at which heart rate decreased sharply with rising temperature (Arrhenius breakpoint temperature, ABT) and at which it fell to zero (flat line temperature, FLT) to calculate thermal safety margins (TSM). Regular exceedance of FLT in sun-exposed microhabitats, a lethal effect, was predicted for only one mid-latitude site. However, ABTs of some individuals were exceeded at sun-exposed microhabitats in most sites, suggesting physiological impairment for snails with poor behavioural thermoregulation and revealing inter-individual variations (physiological polymorphism) of thermal limits. An autocorrelation analysis of T b showed that predictability of extreme temperatures was lowest at the hottest sites, indicating that the effectiveness of behavioural thermoregulation is potentially lowest at these sites. These results illustrate the critical roles of mechanistic studies at small spatial scales when predicting effects of climate change. © 2017 The Author(s).

Untangling the roles of microclimate, behaviour and physiological polymorphism in governing vulnerability of intertidal snails to heat stress

PubMed Central

Li, Xiao-xu; Choi, Francis M. P.; Williams, Gray A.; Somero, George N.; Helmuth, Brian

2017-01-01

Biogeographic distributions are driven by cumulative effects of smaller scale processes. Thus, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature (Tb), microclimatic conditions, and behavioural thermoregulation. To understand interactions among these variables, we analysed the thermal tolerances of three species of intertidal snails from different latitudes along the Chinese coast, and estimated potential Tb in different microhabitats at each site. We then empirically determined the temperatures at which heart rate decreased sharply with rising temperature (Arrhenius breakpoint temperature, ABT) and at which it fell to zero (flat line temperature, FLT) to calculate thermal safety margins (TSM). Regular exceedance of FLT in sun-exposed microhabitats, a lethal effect, was predicted for only one mid-latitude site. However, ABTs of some individuals were exceeded at sun-exposed microhabitats in most sites, suggesting physiological impairment for snails with poor behavioural thermoregulation and revealing inter-individual variations (physiological polymorphism) of thermal limits. An autocorrelation analysis of Tb showed that predictability of extreme temperatures was lowest at the hottest sites, indicating that the effectiveness of behavioural thermoregulation is potentially lowest at these sites. These results illustrate the critical roles of mechanistic studies at small spatial scales when predicting effects of climate change. PMID:28469014

Circadian physiology of metabolism.

PubMed

Panda, Satchidananda

2016-11-25

A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark. Copyright © 2016, American Association for the Advancement of Science.

Physiological roles of taurine in heart and muscle

PubMed Central

2010-01-01

Taurine (aminoethane sulfonic acid) is an ubiquitous compound, found in very high concentrations in heart and muscle. Although taurine is classified as an amino acid, it does not participate in peptide bond formation. Nonetheless, the amino group of taurine is involved in a number of important conjugation reactions as well as in the scavenging of hypochlorous acid. Because taurine is a fairly inert compound, it is an ideal modulator of basic processes, such as osmotic pressure, cation homeostasis, enzyme activity, receptor regulation, cell development and cell signalling. The present review discusses several physiological functions of taurine. First, the observation that taurine depletion leads to the development of a cardiomyopathy indicates a role for taurine in the maintenance of normal contractile function. Evidence is provided that this function of taurine is mediated by changes in the activity of key Ca2+ transporters and the modulation Ca2+ sensitivity of the myofibrils. Second, in some species, taurine is an established osmoregulator, however, in mammalian heart the osmoregulatory function of taurine has recently been questioned. Third, taurine functions as an indirect regulator of oxidative stress. Although this action of taurine has been widely discussed, its mechanism of action is unclear. A potential mechanism for the antioxidant activity of taurine is discussed. Fourth, taurine stabilizes membranes through direct interactions with phospholipids. However, its inhibition of the enzyme, phospholipid N-methyltransferase, alters the phosphatidylcholine and phosphatidylethanolamine content of membranes, which in turn affects the function of key proteins within the membrane. Finally, taurine serves as a modulator of protein kinases and phosphatases within the cardiomyocyte. The mechanism of this action has not been studied. Taurine is a chemically simple compound, but it has profound effects on cells. This has led to the suggestion that taurine is an

Physiological roles of taurine in heart and muscle.

PubMed

Schaffer, Stephen W; Jong, Chian Ju; Ramila, K C; Azuma, Junichi

2010-08-24

Taurine (aminoethane sulfonic acid) is an ubiquitous compound, found in very high concentrations in heart and muscle. Although taurine is classified as an amino acid, it does not participate in peptide bond formation. Nonetheless, the amino group of taurine is involved in a number of important conjugation reactions as well as in the scavenging of hypochlorous acid. Because taurine is a fairly inert compound, it is an ideal modulator of basic processes, such as osmotic pressure, cation homeostasis, enzyme activity, receptor regulation, cell development and cell signalling. The present review discusses several physiological functions of taurine. First, the observation that taurine depletion leads to the development of a cardiomyopathy indicates a role for taurine in the maintenance of normal contractile function. Evidence is provided that this function of taurine is mediated by changes in the activity of key Ca2+ transporters and the modulation Ca2+ sensitivity of the myofibrils. Second, in some species, taurine is an established osmoregulator, however, in mammalian heart the osmoregulatory function of taurine has recently been questioned. Third, taurine functions as an indirect regulator of oxidative stress. Although this action of taurine has been widely discussed, its mechanism of action is unclear. A potential mechanism for the antioxidant activity of taurine is discussed. Fourth, taurine stabilizes membranes through direct interactions with phospholipids. However, its inhibition of the enzyme, phospholipid N-methyltransferase, alters the phosphatidylcholine and phosphatidylethanolamine content of membranes, which in turn affects the function of key proteins within the membrane. Finally, taurine serves as a modulator of protein kinases and phosphatases within the cardiomyocyte. The mechanism of this action has not been studied. Taurine is a chemically simple compound, but it has profound effects on cells. This has led to the suggestion that taurine is an

Neuromedin U: physiology, pharmacology and therapeutic potential.

PubMed

Budhiraja, S; Chugh, A

2009-04-01

Neuromedin U (NmU), a multifunctional neuropeptide, belongs to a family of neuropeptides, the neuromedins. It is ubiquitously distributed with highest levels found in the gastrointestinal tract and pituitary. The conservation of structural elements of NmU across species, the widespread distribution of NmU and its receptors throughout the body point to a fundamental role in key physiological processes. Two G protein coupled receptors for NmU have been cloned NmU R1 and NmU R2. NmU R1 is expressed pre-dominantly in the periphery especially the gastrointestinal tract whereas NmU R2 is expressed pre-dominantly in the central nervous system. Current evidence suggests a role of NmU in pain, in regulation of feeding and energy homeostasis, stress, cancer, immune mediated inflammatory diseases like asthma, inflammatory diseases, maintaining the biological clock, in the regulation of smooth muscle contraction in the gastrointestinal and genitourinary tract, and in the control of blood flow and blood pressure. With the development of drugs selectively acting on receptors and knockout animal models, exact pathophysiological roles of NmU will become clearer.

Class Inclusion and Role-Taking: Structural Mediation.

ERIC Educational Resources Information Center

Gash, Hugh

The mediational linkage between class inclusion and role-taking skills was investigated by studying the effects of a successive perspective-taking training technique on the consolidation of class inclusion structures. Sixty preoperational Irish boys were given two pretest measures of class inclusion and two of role-taking. They were then grouped…

The Role of Exercise in Cardiac Aging: From Physiology to Molecular Mechanisms

PubMed Central

Roh, Jason; Rhee, James; Chaudhari, Vinita; Rosenzweig, Anthony

2015-01-01

Aging induces structural and functional changes in the heart that are associated with increased risk of cardiovascular disease and impaired functional capacity in the elderly. Exercise is a diagnostic and therapeutic tool, with the potential to provide insights into clinical diagnosis and prognosis, as well as the molecular mechanisms by which aging influences cardiac physiology and function. In this review, we first provide an overview of how aging impacts the cardiac response to exercise and the implications this has for functional capacity in older adults. We then review the underlying molecular mechanisms by which cardiac aging contributes to exercise intolerance, and conversely how exercise training can potentially modulate aging phenotypes in the heart. Finally, we highlight the potential use of these exercise models to complement models of disease in efforts to uncover new therapeutic targets to prevent or treat heart disease in the aging population. PMID:26838314

The Role of Exercise in Cardiac Aging: From Physiology to Molecular Mechanisms.

PubMed

Roh, Jason; Rhee, James; Chaudhari, Vinita; Rosenzweig, Anthony

2016-01-22

Aging induces structural and functional changes in the heart that are associated with increased risk of cardiovascular disease and impaired functional capacity in the elderly. Exercise is a diagnostic and therapeutic tool, with the potential to provide insights into clinical diagnosis and prognosis, as well as the molecular mechanisms by which aging influences cardiac physiology and function. In this review, we first provide an overview of how aging impacts the cardiac response to exercise, and the implications this has for functional capacity in older adults. We then review the underlying molecular mechanisms by which cardiac aging contributes to exercise intolerance, and conversely how exercise training can potentially modulate aging phenotypes in the heart. Finally, we highlight the potential use of these exercise models to complement models of disease in efforts to uncover new therapeutic targets to prevent or treat heart disease in the aging population. © 2016 American Heart Association, Inc.

The role of the bidirectional hydrogenase in cyanobacteria.

PubMed

Carrieri, Damian; Wawrousek, Karen; Eckert, Carrie; Yu, Jianping; Maness, Pin-Ching

2011-09-01

Cyanobacteria have tremendous potential to produce clean, renewable fuel in the form of hydrogen gas derived from solar energy and water. Of the two cyanobacterial enzymes capable of evolving hydrogen gas (nitrogenase and the bidirectional hydrogenase), the hox-encoded bidirectional Ni-Fe hydrogenase has a high theoretical potential. The physiological role of this hydrogenase is a highly debated topic and is poorly understood relative to that of the nitrogenase. Here the structure, assembly, and expression of this enzyme, as well as its probable roles in metabolism, are discussed and analyzed to gain perspective on its physiological role. It is concluded that the bidirectional hydrogenase in cyanobacteria primarily functions as a redox regulator for maintaining a proper oxidation/reduction state in the cell. Recommendations for future research to test this hypothesis are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Human physiology in space

NASA Technical Reports Server (NTRS)

Vernikos, J.

1996-01-01

The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.

Has dopamine a physiological role in the control of sexual behavior? A critical review of the evidence.

PubMed

Paredes, Raúl G; Agmo, Anders

2004-06-01

The role of dopaminergic systems in the control of sexual behavior has been a subject of study for at least 40 years. Not surprisingly, reviews of the area have been published at variable intervals. However, the earlier reviews have been summaries of published research rather than a critical analysis of it. They have focused upon the conclusions presented in the original research papers rather than on evaluating the reliability and functional significance of the data reported to support these conclusions. During the last few years, important new knowledge concerning dopaminergic systems and their behavioral functions as well as the possible role of these systems in sexual behavior has been obtained. For the first time, it is now possible to integrate the data obtained in studies of sexual behavior into the wider context of general dopaminergic functions. To make this possible, we first present an analysis of the nature and organization of sexual behavior followed by a summary of current knowledge about the brain structures of crucial importance for this behavior. We then proceed with a description of the dopaminergic systems within or projecting to these structures. Whenever possible, we also try to include data on the electrophysiological actions of dopamine. Thereafter, we proceed with analyses of pharmacological data and release studies, both in males and in females. Consistently throughout this discussion, we make an effort to distinguish pharmacological effects on sexual behavior from a possible physiological role of dopamine. By pharmacological effects, we mean here drug-induced alterations in behavior that are not the result of the normal actions of synaptically released dopamine in the untreated animal. The conclusion of this endeavor is that pharmacological effects of dopaminergic drugs are variable in both males and females, independently of whether the drugs are administered systemically or intracerebrally. We conclude that the pharmacological data

Network Physiology: How Organ Systems Dynamically Interact

PubMed Central

Bartsch, Ronny P.; Liu, Kang K. L.; Bashan, Amir; Ivanov, Plamen Ch.

2015-01-01

We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

Physiological functions of MTA family of proteins.

PubMed

Sen, Nirmalya; Gui, Bin; Kumar, Rakesh

2014-12-01

Although the functional significance of the metastasic tumor antigen (MTA) family of chromatin remodeling proteins in the pathobiology of cancer is fairly well recognized, the physiological role of MTA proteins continues to be an understudied research area and is just beginning to be recognized. Similar to cancer cells, MTA1 also modulates the expression of target genes in normal cells either by acting as a corepressor or coactivator. In addition, physiological functions of MTA proteins are likely to be influenced by its differential expression, subcellular localization, and regulation by upstream modulators and extracellular signals. This review summarizes our current understanding of the physiological functions of the MTA proteins in model systems. In particular, we highlight recent advances of the role MTA proteins play in the brain, eye, circadian rhythm, mammary gland biology, spermatogenesis, liver, immunomodulation and inflammation, cellular radio-sensitivity, and hematopoiesis and differentiation. Based on the growth of knowledge regarding the exciting new facets of the MTA family of proteins in biology and medicine, we speculate that the next burst of findings in this field may reveal further molecular regulatory insights of non-redundant functions of MTA coregulators in the normal physiology as well as in pathological conditions outside cancer.

Ionotropic AMPA-type glutamate and metabotropic GABAB receptors: determining cellular physiology by proteomes.

PubMed

Bettler, Bernhard; Fakler, Bernd

2017-08-01

Ionotropic AMPA-type glutamate receptors and G-protein-coupled metabotropic GABA B receptors are key elements of neurotransmission whose cellular functions are determined by their protein constituents. Over the past couple of years unbiased proteomic approaches identified comprehensive sets of protein building blocks of these two types of neurotransmitter receptors in the brain (termed receptor proteomes). This provided the opportunity to match receptor proteomes with receptor physiology and to study the structural organization, regulation and function of native receptor complexes in an unprecedented manner. In this review we discuss the principles of receptor architecture and regulation emerging from the functional characterization of the proteomes of AMPA and GABA B receptors. We also highlight progress in unraveling the role of unexpected protein components for receptor physiology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fractals in physiology and medicine

NASA Technical Reports Server (NTRS)

Goldberger, Ary L.; West, Bruce J.

1987-01-01

The paper demonstrates how the nonlinear concepts of fractals, as applied in physiology and medicine, can provide an insight into the organization of such complex structures as the tracheobronchial tree and heart, as well as into the dynamics of healthy physiological variability. Particular attention is given to the characteristics of computer-generated fractal lungs and heart and to fractal pathologies in these organs. It is shown that alterations in fractal scaling may underlie a number of pathophysiological disturbances, including sudden cardiac death syndromes.

Zinc: physiology, deficiency, and parenteral nutrition.

PubMed

Livingstone, Callum

2015-06-01

The essential trace element zinc (Zn) has a large number of physiologic roles, in particular being required for growth and functioning of the immune system. Adaptive mechanisms enable the body to maintain normal total body Zn status over a wide range of intakes, but deficiency can occur because of reduced absorption or increased gastrointestinal losses. Deficiency impairs physiologic processes, leading to clinical consequences that include failure to thrive, skin rash, and impaired wound healing. Mild deficiency that is not clinically overt may still cause nonspecific consequences, such as susceptibility to infection and poor growth. The plasma Zn concentration has poor sensitivity and specificity as a test of deficiency. Consequently, diagnosis of deficiency requires a combination of clinical assessment and biochemical tests. Patients receiving parenteral nutrition (PN) are susceptible to Zn deficiency and its consequences. Nutrition support teams should have a strategy for assessing Zn status and optimizing this by appropriate supplementation. Nutrition guidelines recommend generous Zn provision from the start of PN. This review covers the physiology of Zn, the consequences of its deficiency, and the assessment of its status, before discussing its role in PN. © 2015 American Society for Parenteral and Enteral Nutrition.

Betwixt and between: Role conflict, role ambiguity and role definition in project-based dual-leadership structures.

PubMed

Ebbers, Joris J; Wijnberg, Nachoem M

2017-11-01

Project-based organizations in the film industry usually have a dual-leadership structure, based on a division of tasks between the dual leaders - the director and the producer - in which the former is predominantly responsible for the artistic and the latter for the commercial aspects of the film. These organizations also have a role hierarchically below and between the dual leaders: the 1st assistant director. This organizational constellation is likely to lead to role conflict and role ambiguity experienced by the person occupying that particular role. Although prior studies found negative effects of role conflict and role ambiguity, this study shows they can also have beneficial effects because they create space for defining the role expansively that, in turn, can be facilitated by the dual leaders defining their own roles more narrowly. In a more general sense, this study also shows the usefulness of analyzing the antecedents and consequences of roles, role definition, and role crafting in connection to the behavior of occupants of adjacent roles.

Physiologically relevant organs on chips

PubMed Central

Yum, Kyungsuk; Hong, Soon Gweon; Lee, Luke P.

2015-01-01

Recent advances in integrating microengineering and tissue engineering have generated promising microengineered physiological models for experimental medicine and pharmaceutical research. Here we review the recent development of microengineered physiological systems, or organs on chips, that reconstitute the physiologically critical features of specific human tissues and organs and their interactions. This technology uses microengineering approaches to construct organ-specific microenvironments, reconstituting tissue structures, tissue–tissue interactions and interfaces, and dynamic mechanical and biochemical stimuli found in specific organs, to direct cells to assemble into functional tissues. We first discuss microengineering approaches to reproduce the key elements of physiologically important, dynamic mechanical microenvironments, biochemical microenvironments, and microarchitectures of specific tissues and organs in microfluidic cell culture systems. This is followed by examples of microengineered individual organ models that incorporate the key elements of physiological microenvironments into single microfluidic cell culture systems to reproduce organ-level functions. Finally, microengineered multiple organ systems that simulate multiple organ interactions to better represent human physiology, including human responses to drugs, is covered in this review. This emerging organs-on-chips technology has the potential to become an alternative to 2D and 3D cell culture and animal models for experimental medicine, human disease modeling, drug development, and toxicology. PMID:24357624

Prostaglandins in reproductive physiology*

PubMed Central

Craig, Gillian M.

1975-01-01

The role of prostaglandins in reproductive physiology is reviewed with particular emphasis on their possible importance in ovulation in humans. A possible interaction between gonadal steroids, biogenic amines and prostaglandins at hypothalamic-pituitary level, in relation to the release of luteinizing hormone releasing factor, and LH, is discussed. Anomalies regarding the role of oestrogens in LH release are noted, and it is suggested that high oestrogen levels may release prostaglandins from the uterus and/or centrally in humans, in connection with the mid-cycle LH surge and ovulation. A hypothetical role for prostaglandins in sexual behaviour and premenstrual changes is discussed. The hypotheses open up new areas for clinical research to establish the role of prostaglandins in human endocrinology. The need for measurement of prostaglandin metabolites in blood and urine is emphasized. PMID:1089972

Translational physiology: from molecules to public health.

PubMed

Seals, Douglas R

2013-07-15

The term 'translational research' was coined 20 years ago and has become a guiding influence in biomedical research. It refers to a process by which the findings of basic research are extended to the clinical research setting (bench to bedside) and then to clinical practice and eventually health policy (bedside to community). It is a dynamic, multidisciplinary research approach. The concept of translational physiology applies the translational research model to the physiological sciences. It differs from the traditional areas of integrative and clinical physiology by its broad investigative scope of basic research to community health. Translational physiology offers exciting opportunities, but presently is under-developed and -utilized. A key challenge will be to expand physiological research by extending investigations to communities of patients and healthy (or at risk) individuals. This will allow bidirectional physiological investigation throughout the translational continuum: basic research observations can be studied up to the population level, and mechanisms can be assessed by 'reverse translation' in clinical research settings and preclinical models based on initial observations made in populations. Examples of translational physiology questions, experimental approaches, roadblocks and strategies for promotion are discussed. Translational physiology provides a novel framework for physiology programs and an investigational platform for physiologists to study function from molecular events to public health. It holds promise for enhancing the completeness and societal impact of our work, while further solidifying the critical role of physiology in the biomedical research enterprise.

Translational physiology: from molecules to public health

PubMed Central

Seals, Douglas R

2013-01-01

The term ‘translational research’ was coined 20 years ago and has become a guiding influence in biomedical research. It refers to a process by which the findings of basic research are extended to the clinical research setting (bench to bedside) and then to clinical practice and eventually health policy (bedside to community). It is a dynamic, multidisciplinary research approach. The concept of translational physiology applies the translational research model to the physiological sciences. It differs from the traditional areas of integrative and clinical physiology by its broad investigative scope of basic research to community health. Translational physiology offers exciting opportunities, but presently is under-developed and -utilized. A key challenge will be to expand physiological research by extending investigations to communities of patients and healthy (or at risk) individuals. This will allow bidirectional physiological investigation throughout the translational continuum: basic research observations can be studied up to the population level, and mechanisms can be assessed by ‘reverse translation’ in clinical research settings and preclinical models based on initial observations made in populations. Examples of translational physiology questions, experimental approaches, roadblocks and strategies for promotion are discussed. Translational physiology provides a novel framework for physiology programs and an investigational platform for physiologists to study function from molecular events to public health. It holds promise for enhancing the completeness and societal impact of our work, while further solidifying the critical role of physiology in the biomedical research enterprise. PMID:23732641

Deliberate acquisition of competence in physiological breech birth: A grounded theory study.

PubMed

Walker, Shawn; Scamell, Mandie; Parker, Pam

2018-06-01

Research suggests that the skill and experience of the attendant significantly affect the outcomes of vaginal breech births, yet practitioner experience levels are minimal within many contemporary maternity care systems. Due to minimal experience and cultural resistance, few practitioners offer vaginal breech birth, and many practice guidelines and training programmes recommend delivery techniques requiring supine maternal position. Fewer practitioners have skills to support physiological breech birth, involving active maternal movement and choice of birthing position, including upright postures such as kneeling, standing, squatting, or on a birth stool. How professionals learn complex skills contrary to those taught in their local practice settings is unclear. How do professionals develop competence and expertise in physiological breech birth? Nine midwives and five obstetricians with experience facilitating upright physiological breech births participated in semi-structured interviews. Data were analysed iteratively using constructivist grounded theory methods to develop an empirical theory of physiological breech skill acquisition. Among the participants in this research, the deliberate acquisition of competence in physiological breech birth included stages of affinity with physiological birth, critical awareness, intention, identity and responsibility. Expert practitioners operating across local and national boundaries guided less experienced practitioners. The results depict a specialist learning model which could be formalised in sympathetic training programmes, and evaluated. It may also be relevant to developing competence in other specialist/expert roles and innovative practices. Deliberate development of local communities of practice may support professionals to acquire elusive breech skills in a sustainable way. Copyright © 2017 Australian College of Midwives. Published by Elsevier Ltd. All rights reserved.

The barley anion channel, HvALMT1, has multiple roles in guard cell physiology and grain metabolism.

PubMed

Xu, Muyun; Gruber, Benjamin D; Delhaize, Emmanuel; White, Rosemary G; James, Richard A; You, Jiangfeng; Yang, Zhenming; Ryan, Peter R

2015-01-01

The barley (Hordeum vulgare) gene HvALMT1 encodes an anion channel in guard cells and in certain root tissues indicating that it may perform multiple roles. The protein localizes to the plasma membrane and facilitates malate efflux from cells when constitutively expressed in barley plants and Xenopus oocytes. This study investigated the function of HvALMT1 further by identifying its tissue-specific expression and by generating and characterizing RNAi lines with reduced HvALMT1 expression. We show that transgenic plants with 18-30% of wild-type HvALMT1 expression had impaired guard cell function. They maintained higher stomatal conductance in low light intensity and lost water more rapidly from excised leaves than the null segregant control plants. Tissue-specific expression of HvALMT1 was investigated in developing grain and during germination using transgenic barley lines expressing the green fluorescent protein (GFP) with the HvALMT1 promoter. We found that HvALMT1 is expressed in the nucellar projection, the aleurone layer and the scutellum of developing barley grain. Malate release measured from isolated aleurone layers prepared from imbibed grain was significantly lower in the RNAi barley plants compared with control plants. These data provide molecular and physiological evidence that HvALMT1 functions in guard cells, in grain development and during germination. We propose that HvALMT1 releases malate and perhaps other anions from guard cells to promote stomatal closure. The likely roles of HvALMT1 during seed development and grain germination are also discussed. © 2014 Scandinavian Plant Physiology Society.

Molecular Analysis of Atypical Family 18 Chitinase from Fujian Oyster Crassostrea angulata and Its Physiological Role in the Digestive System.

PubMed

Yang, Bingye; Zhang, Mingming; Li, Lingling; Pu, Fei; You, Weiwei; Ke, Caihuan

2015-01-01

Chitinolytic enzymes have an important physiological significance in immune and digestive systems in plants and animals, but chitinase has not been identified as having a role in the digestive system in molluscan. In our study, a novel chitinase homologue, named Ca-Chit, has been cloned and characterized as the oyster Crassostrea angulate. The 3998bp full-length cDNA of Ca-Chit consisted of 23bp 5-UTR, 3288 ORF and 688bp 3-UTR. The deduced amino acids sequence shares homologue with the chitinase of family 18. The molecular weight of the protein was predicted to be 119.389 kDa, with a pI of 6.74. The Ca-Chit protein was a modular enzyme composed of a glycosyl hydrolase family 18 domain, threonine-rich region profile and a putative membrane anchor domain. Gene expression profiles monitored by quantitative RT-PCR in different adult tissues showed that the mRNA of Ca-Chit expressed markedly higher visceral mass than any other tissues. The results of the whole mount in-situ hybridization displayed that Ca-Chit starts to express the visceral mass of D-veliger larvae and then the digestive gland forms a crystalline structure during larval development. Furthermore, the adult oysters challenged by starvation indicated that the Ca-Chit expression would be regulated by feed. All the observations made suggest that Ca-Chit plays an important role in the digestive system of the oyster, Crassostrea angulate.

Molecular Analysis of Atypical Family 18 Chitinase from Fujian Oyster Crassostrea angulata and Its Physiological Role in the Digestive System

PubMed Central

Yang, Bingye; Zhang, Mingming; Li, Lingling; Pu, Fei; You, Weiwei; Ke, Caihuan

2015-01-01

Chitinolytic enzymes have an important physiological significance in immune and digestive systems in plants and animals, but chitinase has not been identified as having a role in the digestive system in molluscan. In our study, a novel chitinase homologue, named Ca-Chit, has been cloned and characterized as the oyster Crassostrea angulate. The 3998bp full-length cDNA of Ca-Chit consisted of 23bp 5-UTR, 3288 ORF and 688bp 3-UTR. The deduced amino acids sequence shares homologue with the chitinase of family 18. The molecular weight of the protein was predicted to be 119.389 kDa, with a pI of 6.74. The Ca-Chit protein was a modular enzyme composed of a glycosyl hydrolase family 18 domain, threonine-rich region profile and a putative membrane anchor domain. Gene expression profiles monitored by quantitative RT-PCR in different adult tissues showed that the mRNA of Ca-Chit expressed markedly higher visceral mass than any other tissues. The results of the whole mount in-situ hybridization displayed that Ca-Chit starts to express the visceral mass of D-veliger larvae and then the digestive gland forms a crystalline structure during larval development. Furthermore, the adult oysters challenged by starvation indicated that the Ca-Chit expression would be regulated by feed. All the observations made suggest that Ca-Chit plays an important role in the digestive system of the oyster, Crassostrea angulate. PMID:26046992

Synthetic lipids and their role in defining macromolecular assemblies.

PubMed

Parrill, Abby L

2015-10-01

Lipids have a variety of physiological roles, ranging from structural and biophysical contributions to membrane functions to signaling contributions in normal and abnormal physiology. This review highlights some of the contributions made by Robert Bittman to our understanding of lipid assemblies through the production of synthetic lipid analogs in the sterol, sphingolipid, and glycolipid classes. His contributions have included the development of a fluorescent cholesterol analog that shows strong functional analogies to cholesterol that has allowed live imaging of cholesterol distribution in living systems, to stereospecific synthetic approaches to both sphingolipid and glycolipid analogs crucial in defining the structure-activity relationships of lipid biological targets. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Arterial elastic fiber structure. Function and potential roles in acute aortic dissection.

PubMed

Pratt, B; Curci, J

2010-10-01

The lethality of acute aortic dissection is well recognized. Successful treatment and prevention of aortic dissection is going to be dependent upon an improved understanding of the molecular and physiologic events which predispose to dissection development and propagation. In this review, we will focus on the elastic fiber, one of the critical elements of the aortic wall matrix. Mechanical or functional failure of the elastin in the wall of the aorta likely predisposes to dissection as well as the post-dissection aortic degeneration with aneurysm formation. Insight into the role of the elastin and the elastic fiber in aortic dissection has recently been accelerated by research into the molecular mechanisms associated with hereditary propensity for aortic dissection, such as Marfan syndrome. These studies have implicated both structural and metabolic contributions of alterations in the scaffolding proteins in matrix elastic fibers. In particular, increased transforming growth factor-β (TGF-β) activity may play a prominent role in predisposing the aortic wall to dissection. The events which predispose to post-dissection aortic degeneration are somewhat less well defined. However, the loss of the structural integrity of the remaining elastic fibers leaves the wall weaker and prone to dilatation and rupture. It appears likely that the upregulation of several potent proteases, particularly those of the matrix metalloproteinase (MMP) family such as MMP-9, are participating in the subsequent matrix damage. Novel medical treatments based on this pathologic data have been proposed and in some cases have made it to clinical trials. The ongoing study evaluating whether therapeutic inhibition of TGF-β may be useful in reducing the risk of aortic dissection in patients at high risk represents one promising new strategy in the treatment of this deadly disease.

Physiology of fish endocrine pancreas.

PubMed

Plisetskaya, E M

1989-06-01

From the very beginning of physiological studies on the endocine pancreas, fish have been used as experimental subjects. Fish insulin was one of the first vertebrate insulins isolated and one of the first insulins whose primary and then tertiary structures were reported. Before a second pancreatic hormone, glucagon, was characterized, a physiologically active 'impurity', similar to that in mammalian insulin preparations, was found in fish insulins.Fish have become the most widely used model for studies of biosynthesis and processing of the pancreatic hormones. It seems inconceivable, therefore, that until the recent past cod and tuna insulins have been the only purified piscine islet hormones available for physiological experiments. The situation has changed remarkably during the last decade.In this review the contemporary status of physiological studies on the fish pancreas is outlined with an emphasis on the following topics: 1) contents of pancreatic peptides in plasma and in islet tissue; 2) actions of piscine pancreatic hormones in fish; 3) specific metabolic consequences of an acute insufficiency of pancreatic peptides; 4) functional interrelations among pancreatic peptides which differ from those of mammals. The pitfalls, lacunae and the perspectives of contemporary physiological studies on fish endocrine pancreas are outlined.

Assessing the antecedents and consequences of threat appraisal of an acute psychosocial stressor: the role of optimism, displacement behavior, and physiological responses.

PubMed

Zandara, Martina; Villada, Carolina; Hidalgo, Vanesa; Salvador, Alicia

2018-03-13

The feeling of stress is increasing in today's societies, particularly in young adults subjected to social evaluative situations in highly competitive academic and work contexts. Threat appraisal is a primary and fundamental reaction when people face a stressful situation. The aim of this study was to investigate the role of dispositional optimism as an antecedent and displacement behavior as a consequence of threat appraisal of a social-evaluative situation of stress. A second objective was to verify the moderating role of physiological responses to stress (heart rate and cortisol reactivity) in the relationship between threat appraisal and displacement behavior. To do this, we combined the Trier Social Stress Test (TSST) with ethological analysis, self-report questionnaires, and physiological data. As expected, people who scored higher on dispositional optimism perceived stress as less threatening, and a higher perception of threat was positively related to displacement behavior patterns. Moreover, the results showed that threat appraisal fully mediates the relationship between dispositional optimism and displacement behavior, and that only heart rate reactivity (not cortisol) moderates the relationship between threat appraisal and displacement behavior.

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…

The unusual amino acid l-ergothioneine is a physiologic cytoprotectant

PubMed Central

Paul, BD; Snyder, SH

2010-01-01

Ergothioneine (ET) is an unusual sulfur-containing derivative of the amino acid, histidine, which is derived exclusively through the diet. Although ET was isolated a century ago, its physiologic function has not been clearly established. Recently, a highly specific transporter for ET (ETT) was identified in mammalian tissues, which explains abundant tissue levels of ET and implies a physiologic role. Using RNA interference, we depleted cells of its transporter. Cells lacking ETT are more susceptible to oxidative stress, resulting in increased mitochondrial DNA damage, protein oxidation and lipid peroxidation. ETT is concentrated in mitochondria, suggesting a specific role in protecting mitochondrial components such as DNA from oxidative damage associated with mitochondrial generation of superoxide. In combating cytotoxic effects of pyrogallol, a known superoxide generator, ET is as potent as glutathione. Because of its dietary origin and the toxicity associated with its depletion, ET may represent a new vitamin whose physiologic roles include antioxidant cytoprotection. PMID:19911007

Distinctive Roles of D-Amino Acids in the Homochiral World: Chirality of Amino Acids Modulates Mammalian Physiology and Pathology.

PubMed

Sasabe, Jumpei; Suzuki, Masataka

2018-05-22

Living organisms enantioselectively employ L-amino acids as the molecular architecture of protein synthesized in the ribosome. Although L-amino acids are dominantly utilized in most biological processes, accumulating evidence points to the distinctive roles of D-amino acids in non-ribosomal physiology. Among the three domains of life, bacteria have the greatest capacity to produce a wide variety of D-amino acids. In contrast, archaea and eukaryotes are thought generally to synthesize only two kinds of D-amino acids: D-serine and D-aspartate. In mammals, D-serine is critical for neurotransmission as an endogenous coagonist of N-methyl D-aspartate receptors. Additionally, D-aspartate is associated with neurogenesis and endocrine systems. Furthermore, recognition of D-amino acids originating in bacteria is linked to systemic and mucosal innate immunity. Among the roles played by D-amino acids in human pathology, the dysfunction of neurotransmission mediated by D-serine is implicated in psychiatric and neurological disorders. Non-enzymatic conversion of L-aspartate or L-serine residues to their D-configurations is involved in age-associated protein degeneration. Moreover, the measurement of plasma or urinary D-/L-serine or D-/L-aspartate levels may have diagnostic or prognostic value in the treatment of kidney diseases. This review aims to summarize current understanding of D-amino-acid-associated biology with a major focus on mammalian physiology and pathology.

Betwixt and between: Role conflict, role ambiguity and role definition in project-based dual-leadership structures

PubMed Central

Ebbers, Joris J; Wijnberg, Nachoem M

2017-01-01

Project-based organizations in the film industry usually have a dual-leadership structure, based on a division of tasks between the dual leaders – the director and the producer – in which the former is predominantly responsible for the artistic and the latter for the commercial aspects of the film. These organizations also have a role hierarchically below and between the dual leaders: the 1st assistant director. This organizational constellation is likely to lead to role conflict and role ambiguity experienced by the person occupying that particular role. Although prior studies found negative effects of role conflict and role ambiguity, this study shows they can also have beneficial effects because they create space for defining the role expansively that, in turn, can be facilitated by the dual leaders defining their own roles more narrowly. In a more general sense, this study also shows the usefulness of analyzing the antecedents and consequences of roles, role definition, and role crafting in connection to the behavior of occupants of adjacent roles. PMID:29081536

Hydrogen Sulfide in Renal Physiology and Disease.

PubMed

Feliers, Denis; Lee, Hak Joo; Kasinath, Balakuntalam S

2016-11-01

Hydrogen sulfide (H2S) has only recently gained recognition for its physiological effects. It is synthesized widely in the mammalian tissues and regulates several biologic processes ranging from development, angiogenesis, neurotransmission to protein synthesis. Recent Advances: The aim of this review is to critically evaluate the evidence for a role for H2S in kidney function and disease. H2S regulates fundamental kidney physiologic processes such as glomerular filtration and sodium reabsorption. In kidney disease states H2S appears to play a complex role in a context-dependent manner. In some disease states such as ischemia-reperfusion and diabetic kidney disease it can serve as an agent that ameliorates kidney injury. In other diseases such as cis-platinum-induced kidney disease it may mediate kidney injury although more investigation is needed. Recent studies have revealed that the actions of nitric oxide and H2S may be integrated in kidney cells. Further studies are needed to understand the full impact of H2S on kidney physiology. As it is endowed with the properties of regulating blood flow, oxidative stress, and inflammation, H2S should be investigated for its role in inflammatory and toxic diseases of the kidney. Such in-depth exploration may identify specific kidney diseases in which H2S may constitute a unique target for therapeutic intervention. Antioxid. Redox Signal. 25, 720-731.

The Role of Dopamine in Normal Rodent Motor Cortex: Physiological Effects and Structural Correlates

DTIC Science & Technology

1999-04-05

things she does on a daily basis made the lab a great place to do research. Susan’s expertise in molecular techniques was evident from day one , and I...applied OA on the spontaneous activity (SA) of PTNs. the receptors that mediate these effects, and DA’s effects on glutamate induced excitation of PTNs...numerous neurons in the motor cortex and may have profound effects on motor cortex activity, through its influence on PTNs. iv The Role of Dopamine in

Physiologically relevant organs on chips.

PubMed

Yum, Kyungsuk; Hong, Soon Gweon; Healy, Kevin E; Lee, Luke P

2014-01-01

Recent advances in integrating microengineering and tissue engineering have generated promising microengineered physiological models for experimental medicine and pharmaceutical research. Here we review the recent development of microengineered physiological systems, or also known as "ogans-on-chips", that reconstitute the physiologically critical features of specific human tissues and organs and their interactions. This technology uses microengineering approaches to construct organ-specific microenvironments, reconstituting tissue structures, tissue-tissue interactions and interfaces, and dynamic mechanical and biochemical stimuli found in specific organs, to direct cells to assemble into functional tissues. We first discuss microengineering approaches to reproduce the key elements of physiologically important, dynamic mechanical microenvironments, biochemical microenvironments, and microarchitectures of specific tissues and organs in microfluidic cell culture systems. This is followed by examples of microengineered individual organ models that incorporate the key elements of physiological microenvironments into single microfluidic cell culture systems to reproduce organ-level functions. Finally, microengineered multiple organ systems that simulate multiple organ interactions to better represent human physiology, including human responses to drugs, is covered in this review. This emerging organs-on-chips technology has the potential to become an alternative to 2D and 3D cell culture and animal models for experimental medicine, human disease modeling, drug development, and toxicology. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physiological functioning of the ear and masking

NASA Technical Reports Server (NTRS)

1984-01-01

The physiological functions of the ear and the role masking plays in speech communication are examined. Topics under investigation include sound analysis of the ear, the aural reflex, and various types of noise masking.

SHP2 sails from physiology to pathology.

PubMed

Tajan, Mylène; de Rocca Serra, Audrey; Valet, Philippe; Edouard, Thomas; Yart, Armelle

2015-10-01

Over the two past decades, mutations of the PTPN11 gene, encoding the ubiquitous protein tyrosine phosphatase SHP2 (SH2 domain-containing tyrosine phosphatase 2), have been identified as the causal factor of several developmental diseases (Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NS-ML), and metachondromatosis), and malignancies (juvenile myelomonocytic leukemia). SHP2 plays essential physiological functions in organism development and homeostasis maintenance by regulating fundamental intracellular signaling pathways in response to a wide range of growth factors and hormones, notably the pleiotropic Ras/Mitogen-Activated Protein Kinase (MAPK) and the Phosphoinositide-3 Kinase (PI3K)/AKT cascades. Analysis of the biochemical impacts of PTPN11 mutations first identified both loss-of-function and gain-of-function mutations, as well as more subtle defects, highlighting the major pathophysiological consequences of SHP2 dysregulation. Then, functional genetic studies provided insights into the molecular dysregulations that link SHP2 mutants to the development of specific traits of the diseases, paving the way for the design of specific therapies for affected patients. In this review, we first provide an overview of SHP2's structure and regulation, then describe its molecular roles, notably its functions in modulating the Ras/MAPK and PI3K/AKT signaling pathways, and its physiological roles in organism development and homeostasis. In the second part, we describe the different PTPN11 mutation-associated pathologies and their clinical manifestations, with particular focus on the biochemical and signaling outcomes of NS and NS-ML-associated mutations, and on the recent advances regarding the pathophysiology of these diseases. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Human physiological responses to wooden indoor environment.

PubMed

Zhang, Xi; Lian, Zhiwei; Wu, Yong

2017-05-15

Previous studies are mainly focused on non-wooden environments, whereas few are concerned with wooden ones. How wooden indoor environments impact the physiology of the occupants is still unclear. The purpose of this study was to explore the distinct physiological responses to wooden and non-wooden indoor environments, assessed by physiological parameters tests including blood pressure, electrocardiogram measurements, electro-dermal activity, oxyhemoglobin saturation, skin temperature, and near distance vision. Twenty healthy adults participated in this experiment, and their physiological responses were evaluated in a 90minute investigation. The results illustrated that; less tension and fatigue were generated in the wooden rooms than in the non-wooden rooms when the participants did their work. In addition, the study also found that the wooden environments benefit the autonomic nervous system, respiratory system, and visual system. Moreover, wooden rooms play a valuable role in physiological regulation and ease function especially after a consecutive period of work. These results provide an experimental basis to support that wooden environment is beneficial to indoor occupants than the non-wooden indoor environment. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of physiological conditions on the surface structure of proteins: Setting the scene for human digestion of emulsions

NASA Astrophysics Data System (ADS)

Maldonado-Valderrama, J.; Gunning, A. P.; Ridout, M. J.; Wilde, P. J.; Morris, V. J.

2009-10-01

Understanding and manipulating the interfacial mechanisms that control human digestion of food emulsions is a crucial step towards improved control of dietary intake. This article reports initial studies on the effects of the physiological conditions within the stomach on the properties of the film formed by the milk protein ( β -lactoglobulin) at the air-water interface. Atomic force microscopy (AFM), surface tension and surface rheology techniques were used to visualize and examine the effect of gastric conditions on the network structure. The effects of changes in temperature, pH and ionic strength on a pre-formed interfacial structure were characterized in order to simulate the actual digestion process. Changes in ionic strength had little effect on the surface properties. In isolation, acidification reduced both the dilatational and the surface shear modulus, mainly due to strong repulsive electrostatic interactions within the surface layer and raising the temperature to body temperature accelerated the rearrangements within the surface layer, resulting in a decrease of the dilatational response and an increase of surface pressure. Together pH and temperature display an unexpected synergism, independent of the ionic strength. Thus, exposure of a pre-formed interfacial β -lactoglobulin film to simulated gastric conditions reduced the surface dilatational modulus and surface shear moduli. This is attributed to a weakening of the surface network in which the surface rearrangements of the protein prior to exposure to gastric conditions might play a crucial role.

[The role of endocannabinoid system in physiological and pathological processes in the eye].

PubMed

Nadolska, Krystyna; Goś, Roman

2008-01-01

Plant of Cannabis sativa/ marihuana except for its psychotropic effects possesses a range of pharmacological properties, that has been utilized for medical purposes over a period of millenia. Investigations concerning biochemical mechanism of action of the main and most active pharmacological compound of Cannabis sativa, cannabinoid 9-THC, contributed to the discovery of cannabinoid receptors both in the central nervous system (CNS) and peripheral tissues, that mediated actions of this substance. The discovery made possible identification of a new, endogenous signaling system reffered to as the endocannabinoid system. Besides cannabinoid receptors CB1 and CB2, the system includes it's endogenic ligands (endocannabinoids) and compounds that participate in their biosynthesis and inactivation. Structure and functioning of the endocannabinoid system is conservative in all vertebrates. It's activation with plant, synthetic and endogenous cannabinoids has an influence on multiple physiological and pathological processes within the eye.

Detection of a novel, integrative aging process suggests complex physiological integration.

PubMed

Cohen, Alan A; Milot, Emmanuel; Li, Qing; Bergeron, Patrick; Poirier, Roxane; Dusseault-Bélanger, Francis; Fülöp, Tamàs; Leroux, Maxime; Legault, Véronique; Metter, E Jeffrey; Fried, Linda P; Ferrucci, Luigi

2015-01-01

Many studies of aging examine biomarkers one at a time, but complex systems theory and network theory suggest that interpretations of individual markers may be context-dependent. Here, we attempted to detect underlying processes governing the levels of many biomarkers simultaneously by applying principal components analysis to 43 common clinical biomarkers measured longitudinally in 3694 humans from three longitudinal cohort studies on two continents (Women's Health and Aging I & II, InCHIANTI, and the Baltimore Longitudinal Study on Aging). The first axis was associated with anemia, inflammation, and low levels of calcium and albumin. The axis structure was precisely reproduced in all three populations and in all demographic sub-populations (by sex, race, etc.); we call the process represented by the axis "integrated albunemia." Integrated albunemia increases and accelerates with age in all populations, and predicts mortality and frailty--but not chronic disease--even after controlling for age. This suggests a role in the aging process, though causality is not yet clear. Integrated albunemia behaves more stably across populations than its component biomarkers, and thus appears to represent a higher-order physiological process emerging from the structure of underlying regulatory networks. If this is correct, detection of this process has substantial implications for physiological organization more generally.

Students' motivation toward laboratory work in physiology teaching.

PubMed

Dohn, Niels Bonderup; Fago, Angela; Overgaard, Johannes; Madsen, Peter Teglberg; Malte, Hans

2016-09-01

The laboratory has been given a central role in physiology education, and teachers report that it is motivating for students to undertake experimental work on live animals or measuring physiological responses on the students themselves. Since motivation is a critical variable for academic learning and achievement, then we must concern ourselves with questions that examine how students engage in laboratory work and persist at such activities. The purpose of the present study was to investigate how laboratory work influences student motivation in physiology. We administered the Lab Motivation Scale to assess our students' levels of interest, willingness to engage (effort), and confidence in understanding (self-efficacy). We also asked students about the role of laboratory work for their own learning and their experience in the physiology laboratory. Our results documented high levels of interest, effort, and self-efficacy among the students. Correlation analyses were performed on the three motivation scales and exam results, yet a significant correlation was only found between self-efficacy in laboratory work and academic performance at the final exam. However, almost all students reported that laboratory work was very important for learning difficult concepts and physiological processes (e.g., action potential), as the hands-on experiences gave a more concrete idea of the learning content and made the content easier to remember. These results have implications for classroom practice as biology students find laboratory exercises highly motivating, despite their different personal interests and subject preferences. This highlights the importance of not replacing laboratory work by other nonpractical approaches, for example, video demonstrations or computer simulations. Copyright © 2016 The American Physiological Society.

Hair and Physiological Baldness

PubMed Central

Mercantini, Edward S.

1965-01-01

Human hair is one of the structures of the body about which little is generally known. Disease affecting the hair is often minimized or ignored by physicians because of lack of knowledge of this rudimentary organ. However, the patient's attitude toward hair loss is very different from the doctor's and he feels great concern about such loss. The development, growth and morphology of human hair are briefly presented. Experimental work which will increase our knowledge of hair growth and loss is reviewed. The various forms of physiological alopecia from birth onward are discussed, with special emphasis on the least-known type of physiological baldness, “male-pattern baldness” in the adult female. PMID:14312445

Biophysical characterization of α-synuclein and its controversial structure

PubMed Central

Alderson, T Reid; Markley, John L

2013-01-01

α-synuclein, a presynaptic protein of poorly defined function, constitutes the main component of Parkinson disease-associated Lewy bodies. Extensive biophysical investigations have provided evidence that isolated α-synuclein is an intrinsically disordered protein (IDP) in vitro. Subsequently serving as a model IDP in numerous studies, α-synuclein has aided in the development of many technologies used to characterize IDPs and arguably represents the most thoroughly analyzed IDP to date. Recent reports, however, have challenged the disordered nature of α-synuclein inside cells and have instead proposed a physiologically relevant helical tetramer. Despite α-synuclein’s rich biophysical history, a single coherent picture has not yet emerged concerning its in vivo structure, dynamics, and physiological role(s). We present herein a review of the biophysical discoveries, developments, and models pertinent to the characterization of α-synuclein’s structure and analysis of the native tetramer controversy. PMID:24634806

Physiology of Food Intake Control in Children.

PubMed

Anderson, G Harvey; Hunschede, Sascha; Akilen, Rajadurai; Kubant, Ruslan

2016-01-01

The purpose of this review is to draw attention to the limited information available on food intake (FI) control in children and adolescents 7-17 y of age, which is essential for developing food policies and guidelines in this population. Although environmental factors have been the overwhelming focus of research on the causative factors of obesity, research focusing on the physiologic control of appetite in children and adolescents is a neglected area of research. To present this message, a review of FI regulation and the role of food and food components in signaling processes are followed by an examination of the role of hormones during puberty in intake regulation. To examine the interaction of environment and physiology on FI regulation, the effects of exercise, television programs, and food advertisements are discussed. In conclusion, although limited, this literature review supports a need for children and adolescents to be a greater focus of research that would lead to sound nutrition policies and actions to reduce chronic disease. A focus on the environment must be balanced with an understanding of physiologic and behavioral changes associated with this age group. © 2016 American Society for Nutrition.

Statistical physics and physiology: monofractal and multifractal approaches

NASA Technical Reports Server (NTRS)

Stanley, H. E.; Amaral, L. A.; Goldberger, A. L.; Havlin, S.; Peng, C. K.

1999-01-01

Even under healthy, basal conditions, physiologic systems show erratic fluctuations resembling those found in dynamical systems driven away from a single equilibrium state. Do such "nonequilibrium" fluctuations simply reflect the fact that physiologic systems are being constantly perturbed by external and intrinsic noise? Or, do these fluctuations actually, contain useful, "hidden" information about the underlying nonequilibrium control mechanisms? We report some recent attempts to understand the dynamics of complex physiologic fluctuations by adapting and extending concepts and methods developed very recently in statistical physics. Specifically, we focus on interbeat interval variability as an important quantity to help elucidate possibly non-homeostatic physiologic variability because (i) the heart rate is under direct neuroautonomic control, (ii) interbeat interval variability is readily measured by noninvasive means, and (iii) analysis of these heart rate dynamics may provide important practical diagnostic and prognostic information not obtainable with current approaches. The analytic tools we discuss may be used on a wider range of physiologic signals. We first review recent progress using two analysis methods--detrended fluctuation analysis and wavelets--sufficient for quantifying monofractual structures. We then describe recent work that quantifies multifractal features of interbeat interval series, and the discovery that the multifractal structure of healthy subjects is different than that of diseased subjects.

Plasticity of brain wave network interactions and evolution across physiologic states

PubMed Central

Liu, Kang K. L.; Bartsch, Ronny P.; Lin, Aijing; Mantegna, Rosario N.; Ivanov, Plamen Ch.

2015-01-01

Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions representing dynamical communications within and between different brain areas in the frequency domain. We introduce the concept of time delay stability (TDS) to quantify coordinated bursts in the activity of brain waves, and we employ a system-wide Network Physiology integrative approach to probe the network of coordinated brain wave activations and its evolution across physiologic states. We find an association between network structure and physiologic states. We uncover a hierarchical reorganization in the brain wave networks in response to changes in physiologic state, indicating new aspects of neural plasticity at the integrated level. Globally, we find that the entire brain network undergoes a pronounced transition from low connectivity in Deep Sleep and REM to high connectivity in Light Sleep and Wake. In contrast, we find that locally, different brain areas exhibit different network dynamics of brain wave interactions to achieve differentiation in function during different sleep stages. Moreover, our analyses indicate that plasticity also emerges in frequency-specific networks, which represent interactions across brain locations mediated through a specific frequency band. Comparing frequency-specific networks within the same physiologic state we find very different degree of

Uriniferous tubule: structural and functional organization.

PubMed

Christensen, Erik Ilsø; Wagner, Carsten A; Kaissling, Brigitte

2012-04-01

The uriniferous tubule is divided into the proximal tubule, the intermediate (thin) tubule, the distal tubule and the collecting duct. The present chapter is based on the chapters by Maunsbach and Christensen on the proximal tubule, and by Kaissling and Kriz on the distal tubule and collecting duct in the 1992 edition of the Handbook of Physiology, Renal Physiology. It describes the fine structure (light and electron microscopy) of the entire mammalian uriniferous tubule, mainly in rats, mice, and rabbits. The structural data are complemented by recent data on the location of the major transport- and transport-regulating proteins, revealed by morphological means(immunohistochemistry, immunofluorescence, and/or mRNA in situ hybridization). The structural differences along the uriniferous tubule strictly coincide with the distribution of the major luminal and basolateral transport proteins and receptors and both together provide the basis for the subdivision of the uriniferous tubule into functional subunits. Data on structural adaptation to defined functional changes in vivo and to genetical alterations of specified proteins involved in transepithelial transport importantly deepen our comprehension of the correlation of structure and function in the kidney, of the role of each segment or cell type in the overall renal function,and our understanding of renal pathophysiology. © 2012 American Physiological Society. Compr Physiol 2:933-996, 2012.

Managing Brain Extracellular K+ during Neuronal Activity: The Physiological Role of the Na+/K+-ATPase Subunit Isoforms

PubMed Central

Larsen, Brian Roland; Stoica, Anca; MacAulay, Nanna

2016-01-01

During neuronal activity in the brain, extracellular K+ rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K+ is the Na+/K+-ATPase, although the relative involvement and physiological impact of the different subunit isoform compositions of the Na+/K+-ATPase remain unresolved. The various cell types in the brain serve a certain temporal contribution in the face of network activity; astrocytes respond directly to the immediate release of K+ from neurons, whereas the neurons themselves become the primary K+ absorbers as activity ends. The kinetic characteristics of the catalytic α subunit isoforms of the Na+/K+-ATPase are, partly, determined by the accessory β subunit with which they combine. The isoform combinations expressed by astrocytes and neurons, respectively, appear to be in line with the kinetic characteristics required to fulfill their distinct physiological roles in clearance of K+ from the extracellular space in the face of neuronal activity. Understanding the nature, impact and effects of the various Na+/K+-ATPase isoform combinations in K+ management in the central nervous system might reveal insights into pathological conditions such as epilepsy, migraine, and spreading depolarization following cerebral ischemia. In addition, particular neurological diseases occur as a result of mutations in the α2- (familial hemiplegic migraine type 2) and α3 isoforms (rapid-onset dystonia parkinsonism/alternating hemiplegia of childhood). This review addresses aspects of the Na+/K+-ATPase in the regulation of extracellular K+ in the central nervous system as well as the related pathophysiology. Understanding the physiological setting in non-pathological tissue would provide a better understanding of the pathological events occurring during disease. PMID:27148079

Imaging for lung physiology: What do we wish we could measure?

PubMed Central

Buxton, Richard B.

2012-01-01

The role of imaging as a tool for investigating lung physiology is growing at an accelerating pace. Looking forward, we wished to identify unresolved issues in lung physiology that might realistically be addressed by imaging methods in development or imaging approaches that could be considered. The role of imaging is framed in terms of the importance of good spatial and temporal resolution and the types of questions that could be addressed as these technical capabilities improve. Recognizing that physiology is fundamentally a quantitative science, a recurring emphasis is on the need for imaging methods that provide reliable measurements of specific physiological parameters. The topics included necessarily reflect our perspective on what are interesting questions and are not meant to be a comprehensive review. Nevertheless, we hope that this essay will be a spur to physiologists to think about how imaging could usefully be applied in their research and to physical scientists developing new imaging methods to attack challenging questions imaging could potentially answer. PMID:22582217

Beyond cellular detoxification: a plethora of physiological roles for MDR transporter homologs in plants

PubMed Central

Remy, Estelle; Duque, Paula

2014-01-01

Higher plants possess a multitude of Multiple Drug Resistance (MDR) transporter homologs that group into three distinct and ubiquitous families—the ATP-Binding Cassette (ABC) superfamily, the Major Facilitator Superfamily (MFS), and the Multidrug And Toxic compound Extrusion (MATE) family. As in other organisms, such as fungi, mammals, and bacteria, MDR transporters make a primary contribution to cellular detoxification processes in plants, mainly through the extrusion of toxic compounds from the cell or their sequestration in the central vacuole. This review aims at summarizing the currently available information on the in vivo roles of MDR transporters in plant systems. Taken together, these data clearly indicate that the biological functions of ABC, MFS, and MATE carriers are not restricted to xenobiotic and metal detoxification. Importantly, the activity of plant MDR transporters also mediates biotic stress resistance and is instrumental in numerous physiological processes essential for optimal plant growth and development, including the regulation of ion homeostasis and polar transport of the phytohormone auxin. PMID:24910617

Pancreatic stellate cell: physiologic role, role in fibrosis and cancer.

PubMed

Apte, Minote; Pirola, Romano C; Wilson, Jeremy S

2015-09-01

Ever since the first descriptions of methods to isolate pancreatic stellate cells (PSCs) from rodent and human pancreas 17 years ago, rapid advances have been made in our understanding of the biology of these cells and their functions in health and disease. This review updates recent literature in the field, which indicates an increasingly complex role for the cells in normal pancreas, pancreatitis and pancreatic cancer. Work reported over the past 12 months includes improved methods of PSC immortalization, a role for PSCs in islet fibrosis, novel factors causing PSC activation as well as those inducing quiescence, and translational research aimed at inhibiting the facilitatory effects of PSCs on disease progression in chronic pancreatitis as well as pancreatic cancer. Improved understanding of the role of PSCs in pancreatic pathophysiology has prompted a focus on translational studies aimed at developing novel approaches to modulate PSC function in a bid to improve clinical outcomes of two major fibrotic diseases of the pancreas: chronic pancreatitis and pancreatic cancer.

Ventricular Assist Devices: Physiology Meets Technology

DTIC Science & Technology

1993-01-01

nmuse’s primary responsbility focuses on the patient . Expert clinical skills plus a thorugh - of the physiology behind VADs are necessary for a nurse...five roles of the CNS to effectively and efficiently manage VAD patients . Expert clinical skills and in-depth knowledge enables the CNS to anticipate

Lipase Maturation Factor 1 (Lmf1): Structure and Role in Lipase Folding and Assembly

PubMed Central

Ehrhardt, Nicole

2014-01-01

Purpose of review Lipase maturation factor 1 (LMF1) is a membrane-bound protein located in the endoplasmic reticulum (ER). It is essential to the folding and assembly (i.e., maturation) of a select group of lipases that include lipoprotein lipase (LPL), hepatic lipase (HL) and endothelial lipase (EL). The purpose of this review is to examine recent studies that have begun to elucidate the structure and function of LMF1, and to place it in the context of lipase folding and assembly. Recent findings Recent studies identified mutations in LMF1 that cause combined lipase deficiency and hypertriglyceridemia in humans. These mutations result in the truncation of a large, evolutionarily conserved domain called DUF1222, which is essential for interaction with lipases and their attainment of enzymatic activity. The structural complexity of LMF1 has been further characterized by solving its topology in the ER membrane. Recent studies indicate that in addition to LPL and HL, the maturation of EL is also dependent on LMF1. Based on its apparent specificity for dimeric lipases, LMF1 is proposed to play an essential role in the assembly and/or stabilization of head-to-tail lipase homodimers. Summary LMF1 functions in the maturation of a select group of secreted lipases that assemble into homodimers in the ER. These dimeric lipases include LPL, HL and EL, all of which contribute significantly to plasma triglyceride and HDL cholesterol levels in human populations. Future studies involving genetically engineered mouse models will be required to fully elucidate the role of LMF1 in normal physiology and disease. PMID:20224398

Functional Neuroanatomy of the Noradrenergic Locus Coeruleus: Its Roles in the Regulation of Arousal and Autonomic Function Part II: Physiological and Pharmacological Manipulations and Pathological Alterations of Locus Coeruleus Activity in Humans

PubMed Central

Samuels, E. R; Szabadi, E

2008-01-01

The locus coeruleus (LC), the major noradrenergic nucleus of the brain, gives rise to fibres innervating most structures of the neuraxis. Recent advances in neuroscience have helped to unravel the neuronal circuitry controlling a number of physiological functions in which the LC plays a central role. Two such functions are the regulation of arousal and autonomic activity, which are inseparably linked largely via the involvement of the LC. Alterations in LC activity due to physiological or pharmacological manipulations or pathological processes can lead to distinct patterns of change in arousal and autonomic function. Physiological manipulations considered here include the presentation of noxious or anxiety-provoking stimuli and extremes in ambient temperature. The modification of LC-controlled functions by drug administration is discussed in detail, including drugs which directly modify the activity of LC neurones (e.g., via autoreceptors, storage, reuptake) or have an indirect effect through modulating excitatory or inhibitory inputs. The early vulnerability of the LC to the ageing process and to neurodegenerative disease (Parkinson’s and Alzheimer’s diseases) is of considerable clinical significance. In general, physiological manipulations and the administration of stimulant drugs, α2-adrenoceptor antagonists and noradrenaline uptake inhibitors increase LC activity and thus cause heightened arousal and activation of the sympathetic nervous system. In contrast, the administration of sedative drugs, including α2-adrenoceptor agonists, and pathological changes in LC function in neurodegenerative disorders and ageing reduce LC activity and result in sedation and activation of the parasympathetic nervous system. PMID:19506724

Devices for noninvasive transcranial electrostimulation of the brain endorphinergic system: application for improvement of human psycho-physiological status.

PubMed

Lebedev, Valery P; Malygin, A V; Kovalevski, A V; Rychkova, S V; Sisoev, V N; Kropotov, S P; Krupitski, E M; Gerasimova, L I; Glukhov, D V; Kozlowski, G P

2002-03-01

It is well known that deficit of endorphins plays an important role in disturbances of human psycho-physiological status. Previously, we revealed that brain endorphinergic structures have quasiresonance characteristics. On the basis of these data, a method of activation of the brain endorphinergic structures by means of noninvasive and rather selective transcranial electrostimulation (TES) as a kind of functional electrical stimulation (FES) was elaborated. New models of TES devices (TRANSAIR) were developed for indoor and outdoor usage. To increase the efficacy of TES, the frequency modulation according to normal distribution in the limits of the quasiresonance characteristics was put into operation. The blind and placebo-controlled (passive and active placebo) study was produced to estimate the TES effects on stress events and accompanied psycho-physiological and autonomic disturbances of different intensities on volunteers and patients in the following groups: everyday stress and fatigue; stress in regular military service and in field conditions; stress in the relatives of those lost in mass disaster; posttraumatic stress (thermal burns); and affective disorders in a postabstinence period. Some subjective verbal and nonverbal tests and objective tests (including heart rate variability) were used for estimation of the initial level of psycho-physiological status, which changes after TES sessions. It was demonstrated that fatigue, stress, and other accompanied psycho-physiological disturbances were significantly improved or abolished after 2-5 TES sessions. The TES effects were more pronounced in cases of heavier disturbances. In conclusion, activation of the brain endorphinergic structures by TES is an effective homeostatic method of FES that sufficiently improves quality of life.

Genetic approaches in comparative and evolutionary physiology.

PubMed

Storz, Jay F; Bridgham, Jamie T; Kelly, Scott A; Garland, Theodore

2015-08-01

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. Copyright © 2015 the American Physiological Society.

Genetic approaches in comparative and evolutionary physiology

PubMed Central

Bridgham, Jamie T.; Kelly, Scott A.; Garland, Theodore

2015-01-01

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. PMID:26041111

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).

Distribution, function and physiological role of melatonin in the lower gut

PubMed Central

Chen, Chun-Qiu; Fichna, Jakub; Bashashati, Mohammad; Li, Yong-Yu; Storr, Martin

2011-01-01

Melatonin is a hormone with endocrine, paracrine and autocrine actions. It is involved in the regulation of multiple functions, including the control of the gastrointestinal (GI) system under physiological and pathophysiological conditions. Since the gut contains at least 400 times more melatonin than the pineal gland, a review of the functional importance of melatonin in the gut seems useful, especially in the context of recent clinical trials. Melatonin exerts its physiological effects through specific membrane receptors, named melatonin-1 receptor (MT1), MT2 and MT3. These receptors can be found in the gut and their involvement in the regulation of GI motility, inflammation and pain has been reported in numerous basic and clinical studies. Stable levels of melatonin in the lower gut that are unchanged following a pinealectomy suggest local synthesis and, furthermore, implicate physiological importance of endogenous melatonin in the GI tract. Presently, only a small number of human studies report possible beneficial and also possible harmful effects of melatonin in case reports and clinical trials. These human studies include patients with lower GI diseases, especially patients with irritable bowel syndrome, inflammatory bowel disease and colorectal cancer. In this review, we summarize the presently available information on melatonin effects in the lower gut and discuss available in vitro and in vivo data. We furthermore aim to evaluate whether melatonin may be useful in future treatment of symptoms or diseases involving the lower gut. PMID:22025877

Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin

NASA Astrophysics Data System (ADS)

Volatron, Jeanne; Kolosnjaj-Tabi, Jelena; Javed, Yasir; Vuong, Quoc Lam; Gossuin, Yves; Neveu, Sophie; Luciani, Nathalie; Hémadi, Miryana; Carn, Florent; Alloyeau, Damien; Gazeau, Florence

2017-01-01

Metallic nanoparticles have been increasingly suggested as prospective therapeutic nanoplatforms, yet their long-term fate and cellular processing in the body is poorly understood. Here we examined the role of an endogenous iron storage protein - namely the ferritin - in the remediation of biodegradable cobalt ferrite magnetic nanoparticles. Structural and elemental analysis of ferritins close to exogenous nanoparticles within spleens and livers of mice injected in vivo with cobalt ferrite nanoparticles, suggests the intracellular transfer of degradation-derived cobalt and iron, entrapped within endogenous protein cages. In addition, the capacity of ferritin cages to accommodate and store the degradation products of cobalt ferrite nanoparticles was investigated in vitro in the acidic environment mimicking the physiological conditions that are present within the lysosomes. The magnetic, colloidal and structural follow-up of nanoparticles and proteins in the lysosome-like medium confirmed the efficient remediation of nanoparticle-released cobalt and iron ions by ferritins in solution. Metal transfer into ferritins could represent a quintessential process in which biomolecules and homeostasis regulate the local degradation of nanoparticles and recycle their by-products.

Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin

PubMed Central

Volatron, Jeanne; Kolosnjaj-Tabi, Jelena; Javed, Yasir; Vuong, Quoc Lam; Gossuin, Yves; Neveu, Sophie; Luciani, Nathalie; Hémadi, Miryana; Carn, Florent; Alloyeau, Damien; Gazeau, Florence

2017-01-01

Metallic nanoparticles have been increasingly suggested as prospective therapeutic nanoplatforms, yet their long-term fate and cellular processing in the body is poorly understood. Here we examined the role of an endogenous iron storage protein – namely the ferritin – in the remediation of biodegradable cobalt ferrite magnetic nanoparticles. Structural and elemental analysis of ferritins close to exogenous nanoparticles within spleens and livers of mice injected in vivo with cobalt ferrite nanoparticles, suggests the intracellular transfer of degradation-derived cobalt and iron, entrapped within endogenous protein cages. In addition, the capacity of ferritin cages to accommodate and store the degradation products of cobalt ferrite nanoparticles was investigated in vitro in the acidic environment mimicking the physiological conditions that are present within the lysosomes. The magnetic, colloidal and structural follow-up of nanoparticles and proteins in the lysosome-like medium confirmed the efficient remediation of nanoparticle-released cobalt and iron ions by ferritins in solution. Metal transfer into ferritins could represent a quintessential process in which biomolecules and homeostasis regulate the local degradation of nanoparticles and recycle their by-products. PMID:28067263

HERV Envelope Proteins: Physiological Role and Pathogenic Potential in Cancer and Autoimmunity

PubMed Central

Grandi, Nicole; Tramontano, Enzo

2018-01-01

Human endogenous retroviruses (HERVs) are relics of ancient infections accounting for about the 8% of our genome. Despite their persistence in human DNA led to the accumulation of mutations, HERVs are still contributing to the human transcriptome, and a growing number of findings suggests that their expression products may have a role in various diseases. Among HERV products, the envelope proteins (Env) are currently highly investigated for their pathogenic properties, which could likely be participating to several disorders with complex etiology, particularly in the contexts of autoimmunity and cancer. In fact, HERV Env proteins have been shown, on the one side, to trigger both innate and adaptive immunity, prompting inflammatory, cytotoxic and apoptotic reactions; and, on the other side, to prevent the immune response activation, presenting immunosuppressive properties and acting as immune downregulators. In addition, HERV Env proteins have been shown to induce abnormal cell-cell fusion, possibly contributing to tumor development and metastasizing processes. Remarkably, even highly defective HERV env genes and alternative env splicing variants can provide further mechanisms of pathogenesis. A well-known example is the HERV-K(HML2) env gene that, depending on the presence or the absence of a 292-bp deletion, can originate two proteins of different length (Np9 and Rec) proposed to have oncogenic properties. The understanding of their involvement in complex pathological disorders made HERV Env proteins potential targets for therapeutic interventions. Of note, a monoclonal antibody directed against a HERV-W Env is currently under clinical trial as therapeutic approach for multiple sclerosis, representing the first HERV-based treatment. The present review will focus on the current knowledge of the HERV Env expression, summarizing its role in human physiology and its possible pathogenic effects in various cancer and autoimmune disorders. It moreover analyzes HERV Env

A multi-species synthesis of physiological mechanisms in drought-induced tree mortality

USGS Publications Warehouse

Adams, Henry D.; Zeppel, Melanie; Anderegg, William R.L.; Hartmann, Henrik; Landhäusser, Simon M.; Tissue, David T.; Huxman, Travis E.; Hudson, Patrick J.; Franz, Trenton E.; Allen, Craig D.; Anderegg, Leander D. L.; Barron-Gafford, Greg A.; Beerling, David; Breshears, David D.; Brodribb, Timothy J.; Bugmann, Harald; Cobb, Richard C.; Collins, Adam D.; Dickman, L. Turin; Duan, Honglang; Ewers, Brent E.; Galiano, Lucia; Galvez, David A.; Garcia-Forner, Núria; Gaylord, Monica L.; Germino, Matthew J.; Gessler, Arthur; Hacke, Uwe G.; Hakamada, Rodrigo; Hector, Andy; Jenkins, Michael W.; Kane, Jeffrey M.; Kolb, Thomas E.; Law, Darin J.; Lewis, James D.; Limousin, Jean-Marc; Love, David; Macalady, Alison K.; Martinez-Vilalta, Jordi; Mencuccini, Maurizio; Mitchell, Patrick J.; Muss, Jordan D.; O'Brien, Michael J.; O'Grady, Anthony P.; Pangle, Robert E.; Pinkard, Elizabeth A.; Piper, Frida I.; Plaut, Jennifer; Pockman, William T.; Quirk, Joe; Reinhardt, Keith; Ripullone, Francesco; Ryan, Michael G.; Sala, Anna; Sevanto, Sanna; Sperry, John S.; Vargas, Rodrigo; Vennetier, Michel; Way, Danielle A.; Wu, Chonggang; Yepez, Enrico A.; McDowell, Nate G.

2017-01-01

Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere–atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.

A multi-species synthesis of physiological mechanisms in drought-induced tree mortality.

PubMed

Adams, Henry D; Zeppel, Melanie J B; Anderegg, William R L; Hartmann, Henrik; Landhäusser, Simon M; Tissue, David T; Huxman, Travis E; Hudson, Patrick J; Franz, Trenton E; Allen, Craig D; Anderegg, Leander D L; Barron-Gafford, Greg A; Beerling, David J; Breshears, David D; Brodribb, Timothy J; Bugmann, Harald; Cobb, Richard C; Collins, Adam D; Dickman, L Turin; Duan, Honglang; Ewers, Brent E; Galiano, Lucía; Galvez, David A; Garcia-Forner, Núria; Gaylord, Monica L; Germino, Matthew J; Gessler, Arthur; Hacke, Uwe G; Hakamada, Rodrigo; Hector, Andy; Jenkins, Michael W; Kane, Jeffrey M; Kolb, Thomas E; Law, Darin J; Lewis, James D; Limousin, Jean-Marc; Love, David M; Macalady, Alison K; Martínez-Vilalta, Jordi; Mencuccini, Maurizio; Mitchell, Patrick J; Muss, Jordan D; O'Brien, Michael J; O'Grady, Anthony P; Pangle, Robert E; Pinkard, Elizabeth A; Piper, Frida I; Plaut, Jennifer A; Pockman, William T; Quirk, Joe; Reinhardt, Keith; Ripullone, Francesco; Ryan, Michael G; Sala, Anna; Sevanto, Sanna; Sperry, John S; Vargas, Rodrigo; Vennetier, Michel; Way, Danielle A; Xu, Chonggang; Yepez, Enrico A; McDowell, Nate G

2017-09-01

Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analysed across species and biomes using a standardized physiological framework. Here, we show that xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or higher loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrate reserves at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in reducing hydraulic function. Our finding that hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.

Physiologically-based kinetic modelling in risk assessment

EPA Science Inventory

The European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) hosted a two-day workshop with an aim to discuss the role and application of Physiologically Based Kinetic (PBK) models in regulatory decision making. The EURL ECVAM strategy document on Toxic...

Political attitudes vary with physiological traits.

PubMed

Oxley, Douglas R; Smith, Kevin B; Alford, John R; Hibbing, Matthew V; Miller, Jennifer L; Scalora, Mario; Hatemi, Peter K; Hibbing, John R

2008-09-19

Although political views have been thought to arise largely from individuals' experiences, recent research suggests that they may have a biological basis. We present evidence that variations in political attitudes correlate with physiological traits. In a group of 46 adult participants with strong political beliefs, individuals with measurably lower physical sensitivities to sudden noises and threatening visual images were more likely to support foreign aid, liberal immigration policies, pacifism, and gun control, whereas individuals displaying measurably higher physiological reactions to those same stimuli were more likely to favor defense spending, capital punishment, patriotism, and the Iraq War. Thus, the degree to which individuals are physiologically responsive to threat appears to indicate the degree to which they advocate policies that protect the existing social structure from both external (outgroup) and internal (norm-violator) threats.

Structural and physiological analyses of the alkanesulphonate-binding protein (SsuA) of the citrus pathogen Xanthomonas citri.

PubMed

Tófoli de Araújo, Fabiano; Bolanos-Garcia, Victor M; Pereira, Cristiane T; Sanches, Mario; Oshiro, Elisa E; Ferreira, Rita C C; Chigardze, Dimitri Y; Barbosa, João Alexandre Gonçalves; de Souza Ferreira, Luís Carlos; Benedetti, Celso E; Blundell, Tom L; Balan, Andrea

2013-01-01

The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen.

Structural and Physiological Analyses of the Alkanesulphonate-Binding Protein (SsuA) of the Citrus Pathogen Xanthomonas citri

PubMed Central

Tófoli de Araújo, Fabiano; Bolanos-Garcia, Victor M.; Pereira, Cristiane T.; Sanches, Mario; Oshiro, Elisa E.; Ferreira, Rita C. C.; Chigardze, Dimitri Y.; Barbosa, João Alexandre Gonçalves; de Souza Ferreira, Luís Carlos; Benedetti, Celso E.; Blundell, Tom L.; Balan, Andrea

2013-01-01

Background The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. Methodology/Principal Findings A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. Conclusions/Significance The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen. PMID:24282519

Biological properties of extracellular vesicles and their physiological functions

PubMed Central

Yáñez-Mó, María; Siljander, Pia R.-M.; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E.; Buzas, Edit I.; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Silva, Anabela Cordeiro-da; Fais, Stefano; Falcon-Perez, Juan M.; Ghobrial, Irene M.; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H. H.; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Hoen, Esther N.M. Nolte-‘t; Nyman, Tuula A.; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; del Portillo, Hernando A.; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N.; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G.; Vasconcelos, M. Helena; Wauben, Marca H. M.; De Wever, Olivier

2015-01-01

In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system. PMID:25979354

Biological properties of extracellular vesicles and their physiological functions.

PubMed

Yáñez-Mó, María; Siljander, Pia R-M; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E; Buzas, Edit I; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Cordeiro-da Silva, Anabela; Fais, Stefano; Falcon-Perez, Juan M; Ghobrial, Irene M; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H H; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Nolte-'t Hoen, Esther N M; Nyman, Tuula A; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; Del Portillo, Hernando A; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G; Vasconcelos, M Helena; Wauben, Marca H M; De Wever, Olivier

2015-01-01

In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

Endurance exercise performance: the physiology of champions

PubMed Central

Joyner, Michael J; Coyle, Edward F

2008-01-01

Efforts to understand human physiology through the study of champion athletes and record performances have been ongoing for about a century. For endurance sports three main factors – maximal oxygen consumption , the so-called ‘lactate threshold’ and efficiency (i.e. the oxygen cost to generate a give running speed or cycling power output) – appear to play key roles in endurance performance. and lactate threshold interact to determine the ‘performance ‘ which is the oxygen consumption that can be sustained for a given period of time. Efficiency interacts with the performance to establish the speed or power that can be generated at this oxygen consumption. This review focuses on what is currently known about how these factors interact, their utility as predictors of elite performance, and areas where there is relatively less information to guide current thinking. In this context, definitive ideas about the physiological determinants of running and cycling efficiency is relatively lacking in comparison with and the lactate threshold, and there is surprisingly limited and clear information about the genetic factors that might pre-dispose for elite performance. It should also be cautioned that complex motivational and sociological factors also play important roles in who does or does not become a champion and these factors go far beyond simple physiological explanations. Therefore, the performance of elite athletes is likely to defy the types of easy explanations sought by scientific reductionism and remain an important puzzle for those interested in physiological integration well into the future. PMID:17901124

Teacher role stress, satisfaction, commitment, and intentions to leave: a structural model.

PubMed

Conley, Sharon; You, Sukkyung

2009-12-01

Structural equation modeling was used to assess the plausibility of a conceptual model specifying hypothesized linkages among teachers' perceptions of the role stresses of role ambiguity, role conflict, and role overload and commitment, satisfaction, and intentions to leave their employing school. 178 teachers in four high schools in a southern coastal region of California responded to survey questions designed to capture the above constructs. Confirmatory factor analysis was used to assess whether the role-stress items fit hypothesized constructs. Structural equation modeling results indicated that satisfaction and commitment are two mediators in the role stresses-intentions to leave relationship.

The emergence of Applied Physiology within the discipline of Physiology.

PubMed

Tipton, Charles M

2016-08-01

Despite the availability and utilization of the physiology textbooks authored by Albrecht von Haller during the 18th century that heralded the modern age of physiology, not all physicians or physiologists were satisfied with its presentation, contents, or application to medicine. Initial reasons were fundamental disagreements between the "mechanists," represented by Boerhaave, Robinson, and von Haller, and the "vitalists," represented by the faculty and graduates of the Montpellier School of Medicine in France, notably, Bordeu and Barthez. Subsequently, objections originated from Europe, United Kingdom, and the United States in publications that focused not only on the teaching of physiology to medical and secondary students, but on the specific applications of the content of physiology to medicine, health, hygiene, pathology, and chronic diseases. At the turn of the 20th century, texts began to appear with applied physiology in their titles and in 1926, physician Samson Wright published a textbook entitled Applied Physiology that was intended for both medical students and the medical profession. Eleven years later, physicians Best and Taylor published The Physiological Basis of Medical Practice: A University of Toronto Texbook in Applied Physiology Although both sets of authors defined the connection between applied physiology and physiology, they failed to define the areas of physiology that were included within applied physiology. This was accomplished by the American Physiological Society (APS) Publications Committee in 1948 with the publication of the Journal of Appplied Physiology, that stated the word "applied" would broadly denote human physiology whereas the terms stress and environment would broadly include work, exercise, plus industrial, climatic and social factors. NIH established a study section (SS) devoted to applied physiology in 1964 which remained active until 2001 when it became amalgamated into other SSs. Before the end of the 20th century when

Physiological changes in neurodegeneration - mechanistic insights and clinical utility.

PubMed

Ahmed, Rebekah M; Ke, Yazi D; Vucic, Steve; Ittner, Lars M; Seeley, William; Hodges, John R; Piguet, Olivier; Halliday, Glenda; Kiernan, Matthew C

2018-05-01

The effects of neurodegenerative syndromes extend beyond cognitive function to involve key physiological processes, including eating and metabolism, autonomic nervous system function, sleep, and motor function. Changes in these physiological processes are present in several conditions, including frontotemporal dementia, amyotrophic lateral sclerosis, Alzheimer disease and the parkinsonian plus conditions. Key neural structures that mediate physiological changes across these conditions include neuroendocrine and hypothalamic pathways, reward pathways, motor systems and the autonomic nervous system. In this Review, we highlight the key changes in physiological processing in neurodegenerative syndromes and the similarities in these changes between different progressive neurodegenerative brain conditions. The changes and similarities between disorders might provide novel insights into the human neural correlates of physiological functioning. Given the evidence that physiological changes can arise early in the neurodegenerative process, these changes could provide biomarkers to aid in the early diagnosis of neurodegenerative diseases and in treatment trials.

Case Study Analysis and the Remediation of Misconceptions about Respiratory Physiology

ERIC Educational Resources Information Center

Cliff, William H.

2006-01-01

Most students enter the physiology classroom with one or more fundamental misconceptions about respiratory physiology. This study examined the prevalence of four respiratory misconceptions and determined the role of case analysis in the remediation of one of them. A case study was used to help students learn about oxygen transport in the blood and…

Physiology of Food Intake Control in Children123

PubMed Central

Anderson, G Harvey; Hunschede, Sascha; Akilen, Rajadurai; Kubant, Ruslan

2016-01-01

The purpose of this review is to draw attention to the limited information available on food intake (FI) control in children and adolescents 7–17 y of age, which is essential for developing food policies and guidelines in this population. Although environmental factors have been the overwhelming focus of research on the causative factors of obesity, research focusing on the physiologic control of appetite in children and adolescents is a neglected area of research. To present this message, a review of FI regulation and the role of food and food components in signaling processes are followed by an examination of the role of hormones during puberty in intake regulation. To examine the interaction of environment and physiology on FI regulation, the effects of exercise, television programs, and food advertisements are discussed. In conclusion, although limited, this literature review supports a need for children and adolescents to be a greater focus of research that would lead to sound nutrition policies and actions to reduce chronic disease. A focus on the environment must be balanced with an understanding of physiologic and behavioral changes associated with this age group. PMID:26773031

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

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.

[Effect of mechanical grinding of Sphagnum on the structure and physiological state of bacterial communities].

PubMed

Dobrovol'skaya, T G; Golovchenko, A V; Yakushev, A V; Manucharova, N A; Yurchenko, E N

2014-01-01

The microcosm method was used to demonstrate an increase in bacterial numbers and drastic changes in the taxonomic structure of saprotrophic bacteria as a result of mechanical grinding of Sphagnum moss. Ekkrisotrophic agrobacteria predominant in untreated moss were replaced by hydrolytic bacteria. Molecular biological approaches revealed such specific hydrolytic bacteria as Janthinobacterium agaricum and Streptomyces purpurascens among the dominant taxa. The application of kinetic technique for determination of the physiological state of bacteria in situ revealed higher functional diversity of hydrolytic bacteria in ground moss than in untreated samples. A considerable decrease of the C/N ratio in ground samples of living Sphagnum incubated using the microcosm technique indicated decomposition of this substrate.

Physiology of bile secretion.

PubMed

Esteller, Alejandro

2008-10-07

The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bile-duct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology.

Plant Ion Channels: Gene Families, Physiology, and Functional Genomics Analyses

PubMed Central

Ward, John M.; Mäser, Pascal; Schroeder, Julian I.

2016-01-01

Distinct potassium, anion, and calcium channels in the plasma membrane and vacuolar membrane of plant cells have been identified and characterized by patch clamping. Primarily owing to advances in Arabidopsis genetics and genomics, and yeast functional complementation, many of the corresponding genes have been identified. Recent advances in our understanding of ion channel genes that mediate signal transduction and ion transport are discussed here. Some plant ion channels, for example, ALMT and SLAC anion channel subunits, are unique. The majority of plant ion channel families exhibit homology to animal genes; such families include both hyperpolarization-and depolarization-activated Shaker-type potassium channels, CLC chloride transporters/channels, cyclic nucleotide–gated channels, and ionotropic glutamate receptor homologs. These plant ion channels offer unique opportunities to analyze the structural mechanisms and functions of ion channels. Here we review gene families of selected plant ion channel classes and discuss unique structure-function aspects and their physiological roles in plant cell signaling and transport. PMID:18842100

Plant ion channels: gene families, physiology, and functional genomics analyses.

PubMed

Ward, John M; Mäser, Pascal; Schroeder, Julian I

2009-01-01

Distinct potassium, anion, and calcium channels in the plasma membrane and vacuolar membrane of plant cells have been identified and characterized by patch clamping. Primarily owing to advances in Arabidopsis genetics and genomics, and yeast functional complementation, many of the corresponding genes have been identified. Recent advances in our understanding of ion channel genes that mediate signal transduction and ion transport are discussed here. Some plant ion channels, for example, ALMT and SLAC anion channel subunits, are unique. The majority of plant ion channel families exhibit homology to animal genes; such families include both hyperpolarization- and depolarization-activated Shaker-type potassium channels, CLC chloride transporters/channels, cyclic nucleotide-gated channels, and ionotropic glutamate receptor homologs. These plant ion channels offer unique opportunities to analyze the structural mechanisms and functions of ion channels. Here we review gene families of selected plant ion channel classes and discuss unique structure-function aspects and their physiological roles in plant cell signaling and transport.

Biochemistry and control of the reductive tricarboxylic acid pathway of CO 2 fixation and physiological role of the Rubis CO-like protein

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

Tabita, F. Robert

2008-12-04

During the past years of this project we have made progress relative to the two major goals of the proposal: (1) to study the biochemistry and regulation of the reductive TCA cycle of CO 2 fixation and (2) to probe the physiological role of a RubisCO-like protein (RLP). Both studies primarily employ the green sulfur bacterium Chlorobium tepidum as well as other photosynthetic bacteria including Rhodospirillum rubrum and Rhodopseudomonas palustris.

Ovarian expression of cellular Ki-ras p21 varies with physiological status.

PubMed Central

Palejwala, S; Goldsmith, L T

1992-01-01

To elucidate the potential role of the ras protooncogene proteins in a specific tissue, the present study determined the levels of individual c-ras-encoded p21 proteins in the rat ovary during various stages of physiological function. p21 protein was extracted from ovaries taken from immature normal female rats, mature nonpregnant animals in the metestrus stage of the estrus cycle, rats at various stages of pregnancy, and actively lactating animals. Levels of individual p21s were evaluated by immunoblot analysis with specific antibodies to the p21 proteins encoded by the Kirsten, Harvey, and neuroblastoma c-ras protooncogenes, c-Ki-ras, c-Ha-ras, and N-ras. Results showed that c-Ki-ras p21 is at its lowest level in the immature ovary and increases with development of the corpora lutea to its highest levels at day 16 of pregnancy, after which levels decline and then rise again during lactation. This pattern, which mimics that of circulating progesterone levels, suggests that ovarian c-Ki-ras p21 levels are regulated and that c-Ki-ras p21 plays a role in the differentiated function of the rat ovary, likely the luteal compartment. In contrast, levels of c-N-ras p21 did not appear to vary with changes in the physiological function of the ovary but appeared to be constitutive. A preferential role for the c-Ki-ras p21 may be due to the documented unique differences in the structure of the carboxyl terminus of this particular c-ras p21. Images PMID:1570348

The Heterogeneity and Spatial Patterning of Structure and Physiology across the Leaf Surface in Giant Leaves of Alocasia macrorrhiza

PubMed Central

Li, Shuai; Zhang, Yong-Jiang; Sack, Lawren; Scoffoni, Christine; Ishida, Atsushi; Chen, Ya-Jun; Cao, Kun-Fang

2013-01-01

Leaf physiology determines the carbon acquisition of the whole plant, but there can be considerable variation in physiology and carbon acquisition within individual leaves. Alocasia macrorrhiza (L.) Schott is an herbaceous species that can develop very large leaves of up to 1 m in length. However, little is known about the hydraulic and photosynthetic design of such giant leaves. Based on previous studies of smaller leaves, and on the greater surface area for trait variation in large leaves, we hypothesized that A. macrorrhiza leaves would exhibit significant heterogeneity in structure and function. We found evidence of reduced hydraulic supply and demand in the outer leaf regions; leaf mass per area, chlorophyll concentration, and guard cell length decreased, as did stomatal conductance, net photosynthetic rate and quantum efficiency of photosystem II. This heterogeneity in physiology was opposite to that expected from a thinner boundary layer at the leaf edge, which would have led to greater rates of gas exchange. Leaf temperature was 8.8°C higher in the outer than in the central region in the afternoon, consistent with reduced stomatal conductance and transpiration caused by a hydraulic limitation to the outer lamina. The reduced stomatal conductance in the outer regions would explain the observed homogeneous distribution of leaf water potential across the leaf surface. These findings indicate substantial heterogeneity in gas exchange across the leaf surface in large leaves, greater than that reported for smaller-leafed species, though the observed structural differences across the lamina were within the range reported for smaller-leafed species. Future work will determine whether the challenge of transporting water to the outer regions can limit leaf size for plants experiencing drought, and whether the heterogeneity of function across the leaf surface represents a particular disadvantage for large simple leaves that might explain their global rarity, even in

The heterogeneity and spatial patterning of structure and physiology across the leaf surface in giant leaves of Alocasia macrorrhiza.

PubMed

Li, Shuai; Zhang, Yong-Jiang; Sack, Lawren; Scoffoni, Christine; Ishida, Atsushi; Chen, Ya-Jun; Cao, Kun-Fang

2013-01-01

Leaf physiology determines the carbon acquisition of the whole plant, but there can be considerable variation in physiology and carbon acquisition within individual leaves. Alocasia macrorrhiza (L.) Schott is an herbaceous species that can develop very large leaves of up to 1 m in length. However, little is known about the hydraulic and photosynthetic design of such giant leaves. Based on previous studies of smaller leaves, and on the greater surface area for trait variation in large leaves, we hypothesized that A. macrorrhiza leaves would exhibit significant heterogeneity in structure and function. We found evidence of reduced hydraulic supply and demand in the outer leaf regions; leaf mass per area, chlorophyll concentration, and guard cell length decreased, as did stomatal conductance, net photosynthetic rate and quantum efficiency of photosystem II. This heterogeneity in physiology was opposite to that expected from a thinner boundary layer at the leaf edge, which would have led to greater rates of gas exchange. Leaf temperature was 8.8°C higher in the outer than in the central region in the afternoon, consistent with reduced stomatal conductance and transpiration caused by a hydraulic limitation to the outer lamina. The reduced stomatal conductance in the outer regions would explain the observed homogeneous distribution of leaf water potential across the leaf surface. These findings indicate substantial heterogeneity in gas exchange across the leaf surface in large leaves, greater than that reported for smaller-leafed species, though the observed structural differences across the lamina were within the range reported for smaller-leafed species. Future work will determine whether the challenge of transporting water to the outer regions can limit leaf size for plants experiencing drought, and whether the heterogeneity of function across the leaf surface represents a particular disadvantage for large simple leaves that might explain their global rarity, even in

Current Practices in the Delivery of Undergraduate Exercise Physiology Content

ERIC Educational Resources Information Center

Fisher, Michele M.

2013-01-01

The purpose of this study was to identify current practices for the delivery of exercise physiology content at the undergraduate level. An anonymous 22-item survey was sent to instructors of exercise physiology to collect information concerning the structure of course offerings and instructional practices. One hundred ten instructors responded to…

Sensitivity analysis of physiological factors in space habitat design

NASA Technical Reports Server (NTRS)

Billingham, J.

1982-01-01

The costs incurred by design conservatism in space habitat design are discussed from a structural standpoint, and areas of physiological research into less than earth-normal conditions that offer the greatest potential decrease in habitat construction and operating costs are studied. The established range of human tolerance limits is defined for those physiological conditions which directly affect habitat structural design. These entire ranges or portions thereof are set as habitat design constraints as a function of habitat population and degree of ecological closure. Calculations are performed to determine the structural weight and cost associated with each discrete population size and its selected environmental conditions, on the basis of habitable volume equivalence for four basic habitat configurations: sphere, cylinder with hemispherical ends, torus, and crystal palace.

The Physiology of Fear: Reconceptualizing the Role of the Central Amygdala in Fear Learning

PubMed Central

Keifer, Orion P.; Hurt, Robert C.; Ressler, Kerry J.

2015-01-01

The historically understood role of the central amygdala (CeA) in fear learning is to serve as a passive output station for processing and plasticity that occurs elsewhere in the brain. However, recent research has suggested that the CeA may play a more dynamic role in fear learning. In particular, there is growing evidence that the CeA is a site of plasticity and memory formation, and that its activity is subject to tight regulation. The following review examines the evidence for these three main roles of the CeA as they relate to fear learning. The classical role of the CeA as a routing station to fear effector brain structures like the periaqueductal gray, the lateral hypothalamus, and paraventricular nucleus of the hypothalamus will be briefly reviewed, but specific emphasis is placed on recent literature suggesting that the CeA 1) has an important role in the plasticity underlying fear learning, 2) is involved in regulation of other amygdala subnuclei, and 3) is itself regulated by intra- and extra-amygdalar input. Finally, we discuss the parallels of human and mouse CeA involvement in fear disorders and fear conditioning, respectively. PMID:26328883

Inferring Nonlinear Neuronal Computation Based on Physiologically Plausible Inputs

PubMed Central

McFarland, James M.; Cui, Yuwei; Butts, Daniel A.

2013-01-01

The computation represented by a sensory neuron's response to stimuli is constructed from an array of physiological processes both belonging to that neuron and inherited from its inputs. Although many of these physiological processes are known to be nonlinear, linear approximations are commonly used to describe the stimulus selectivity of sensory neurons (i.e., linear receptive fields). Here we present an approach for modeling sensory processing, termed the Nonlinear Input Model (NIM), which is based on the hypothesis that the dominant nonlinearities imposed by physiological mechanisms arise from rectification of a neuron's inputs. Incorporating such ‘upstream nonlinearities’ within the standard linear-nonlinear (LN) cascade modeling structure implicitly allows for the identification of multiple stimulus features driving a neuron's response, which become directly interpretable as either excitatory or inhibitory. Because its form is analogous to an integrate-and-fire neuron receiving excitatory and inhibitory inputs, model fitting can be guided by prior knowledge about the inputs to a given neuron, and elements of the resulting model can often result in specific physiological predictions. Furthermore, by providing an explicit probabilistic model with a relatively simple nonlinear structure, its parameters can be efficiently optimized and appropriately regularized. Parameter estimation is robust and efficient even with large numbers of model components and in the context of high-dimensional stimuli with complex statistical structure (e.g. natural stimuli). We describe detailed methods for estimating the model parameters, and illustrate the advantages of the NIM using a range of example sensory neurons in the visual and auditory systems. We thus present a modeling framework that can capture a broad range of nonlinear response functions while providing physiologically interpretable descriptions of neural computation. PMID:23874185

The Mediator complex of Caenorhabditis elegans: insights into the developmental and physiological roles of a conserved transcriptional coregulator

PubMed Central

Grants, Jennifer M.; Goh, Grace Y. S.; Taubert, Stefan

2015-01-01

The Mediator multiprotein complex (‘Mediator’) is an important transcriptional coregulator that is evolutionarily conserved throughout eukaryotes. Although some Mediator subunits are essential for the transcription of all protein-coding genes, others influence the expression of only subsets of genes and participate selectively in cellular signaling pathways. Here, we review the current knowledge of Mediator subunit function in the nematode Caenorhabditis elegans, a metazoan in which established and emerging genetic technologies facilitate the study of developmental and physiological regulation in vivo. In this nematode, unbiased genetic screens have revealed critical roles for Mediator components in core developmental pathways such as epidermal growth factor (EGF) and Wnt/β-catenin signaling. More recently, important roles for C. elegans Mediator subunits have emerged in the regulation of lipid metabolism and of systemic stress responses, engaging conserved transcription factors such as nuclear hormone receptors (NHRs). We emphasize instances where similar functions for individual Mediator subunits exist in mammals, highlighting parallels between Mediator subunit action in nematode development and in human cancer biology. We also discuss a parallel between the association of the Mediator subunit MED12 with several human disorders and the role of its C. elegans ortholog mdt-12 as a regulatory hub that interacts with numerous signaling pathways. PMID:25634893

Physiological Strain in French Vineyard Workers Wearing Protective Equipment to Conduct Re-Entry Tasks in Humid Conditions.

PubMed

Grimbuhler, Sonia; Viel, Jean-François

2018-06-19

The proper use of personal protective equipment (PPE) plays an important role in reducing exposure to pesticides in vineyard farming activities, including re-entry tasks. However, discomfort from clothing systems may increase the physiological burden on workers. We compared the physiological burdens of vineyard workers wearing three different types of PPE during canopy management in field humid conditions while accounting for occupational, climatic, and geographical environments. The study was conducted in the Bordeaux vineyards of southern France during June 2012. A total of 42 workers from seven vineyards consented to field observations. The following PPE garments were randomly allocated: HF Estufa polyamide (Brisa®), Tyvek® Classic Plus, and Tychem® C Standard. Participant sociodemographic characteristics were collected using a structured questionnaire. Skin temperature and heart rate were monitored continuously using portable devices. Multivariate multilevel linear regression models were performed to account for the hierarchical structure of data. No significant difference was found for mean skin temperature during work. Regardless of the cardiac strain parameter considered, the Tyvek® Classic Plus garment produced the poorest results (P ≤ 0.03). Under the very humid conditions encountered during the field study, the thinness and breathability of the Tyvek® Classic Plus garment resulted in undergarment humidity, imposing additional physiological burden on vineyard workers. These results confirm that the idea of using generic coveralls in any farming activity is unsuitable. Compromises should be created between physiological costs and protection, depending on the agricultural task performed, the crop grown, and the environmental conditions encountered.

Use of Wikiversity and Role Play to Increase Student Engagement during Student-Led Physiology Seminars

ERIC Educational Resources Information Center

Singh, Satendra

2013-01-01

The Undergraduate Medical Program (Bachelor of Medicine and Bachelor of Surgery) at University College of Medical Sciences (Delhi, India) is a 4.5-yr, intense academic program where physiology is taught in the first year. To make the learning experience enriching, the Department of Physiology organizes four student seminars (two seminars/semester)…

The Role of Structure in Learning Non-Euclidean Geometry

ERIC Educational Resources Information Center

Asmuth, Jennifer A.

2009-01-01

How do people learn novel mathematical information that contradicts prior knowledge? The focus of this thesis is the role of structure in the acquisition of knowledge about hyperbolic geometry, a non-Euclidean geometry. In a series of three experiments, I contrast a more holistic structure--training based on closed figures--with a mathematically…

Role of leptin in energy-deprivation states: normal human physiology and clinical implications for hypothalamic amenorrhoea and anorexia nervosa.

PubMed

Chan, Jean L; Mantzoros, Christos S

Leptin is an adipocyte-secreted hormone that plays a key part in energy homoeostasis. Advances in leptin physiology have established that the main role of this hormone is to signal energy availability in energy-deficient states. Studies in animals and human beings have shown that low concentrations of leptin are fully or partly responsible for starvation-induced changes in neuroendocrine axes, including low reproductive, thyroid, and insulin-like growth factor (IGF) hormones. Disease states such as exercise-induced hypothalamic amenorrhoea and anorexia nervosa are also associated with low concentrations of leptin and a similar spectrum of neuroendocrine abnormalities. We have recently shown in an interventional, proof-of-concept study that leptin can restore ovulatory menstrual cycles and improve reproductive, thyroid, and IGF hormones and bone markers in hypothalamic amenorrhoea. Further studies are warranted to establish the safety and effectiveness of leptin for the infertility and osteoporosis associated with hypothalamic amenorrhoea, and to clarify its role in anorexia nervosa.

The role of ascorbate peroxidase, guaiacol peroxidase, and polysaccharides in cassava (Manihot esculenta Crantz) roots under postharvest physiological deterioration.

PubMed

Uarrota, Virgílio Gavicho; Moresco, Rodolfo; Schmidt, Eder Carlos; Bouzon, Zenilda Laurita; Nunes, Eduardo da Costa; Neubert, Enilto de Oliveira; Peruch, Luiz Augusto Martins; Rocha, Miguel; Maraschin, Marcelo

2016-04-15

This study aimed to investigate the role of ascorbate peroxidase (APX), guaiacol peroxidase (GPX), polysaccharides, and protein contents associated with the early events of postharvest physiological deterioration (PPD) in cassava roots. Increases in APX and GPX activity, as well as total protein contents occurred from 3 to 5 days of storage and were correlated with the delay of PPD. Cassava samples stained with Periodic Acid-Schiff (PAS) highlighted the presence of starch and cellulose. Degradation of starch granules during PPD was also detected. Slight metachromatic reaction with toluidine blue is indicative of increasing of acidic polysaccharides and may play an important role in PPD delay. Principal component analysis (PCA) classified samples according to their levels of enzymatic activity based on the decision tree model which showed GPX and total protein amounts to be correlated with PPD. The Oriental (ORI) cultivar was more susceptible to PPD. Copyright © 2015 Elsevier Ltd. All rights reserved.

Exploring the Limits of Cell Adhesion under Shear Stress within Physiological Conditions and beyond on a Chip.

PubMed

Stamp, Melanie E M; Jötten, Anna M; Kudella, Patrick W; Breyer, Dominik; Strobl, Florian G; Geislinger, Thomas M; Wixforth, Achim; Westerhausen, Christoph

2016-10-21

Cell adhesion processes are of ubiquitous importance for biomedical applications such as optimization of implant materials. Here, not only physiological conditions such as temperature or pH, but also topographical structures play crucial roles, as inflammatory reactions after surgery can diminish osseointegration. In this study, we systematically investigate cell adhesion under static, dynamic and physiologically relevant conditions employing a lab-on-a-chip system. We screen adhesion of the bone osteosarcoma cell line SaOs-2 on a titanium implant material for pH and temperature values in the physiological range and beyond, to explore the limits of cell adhesion, e.g., for feverish and acidic conditions. A detailed study of different surface roughness R q gives insight into the correlation between the cells' abilities to adhere and withstand shear flow and the topography of the substrates, finding a local optimum at R q = 22 nm. We use shear stress induced by acoustic streaming to determine a measure for the ability of cell adhesion under an external force for various conditions. We find an optimum of cell adhesion for T = 37 °C and pH = 7.4 with decreasing cell adhesion outside the physiological range, especially for high T and low pH. We find constant detachment rates in the physiological regime, but this behavior tends to collapse at the limits of 41 °C and pH 4.

[PHYSIOLOGY AND PHARMACOLOGICAL PROPERTIES OF NANOMATERIALS].

PubMed

Chekman, I S

2015-01-01

Literature data and results of our department studies on theoretical and practical basics of nanoscience were summarized in the article. Much attention is paid to research in the field of physical, chemical, biological, medical, physiological, pharmacological, and toxicological properties of nanomaterials with the aim of their wider implementation into practice lately. The discovery of new quantum/wave properties of nanoparticles is of particular importance. The author of the article advances an idea: wave properties of nanomaterials play greater role with a decrease in particle size. The preponderance of wave properties compared with corpuscular ones in nanostructures determines a great change in their physical. chemical properties and an increase in physical, mechanical biological, physiological, pharmacological, and toxicologica activity. The idea advanced in the article hasn't been verified by theoretical or experimental studies for now. Joined efforts of scientists of different scientific fields are needed. A confirmation of hypothesis by specific findings will be of great importance for physiology, medicine, pharmacology and promote an implementation of new efficacious preparations into clinical practice. New fundamental discoveries could be made only by multidisciplinary approach.

A multi-species synthesis of physiological mechanisms in drought-induced tree mortality

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

Adams, Henry D.; Zeppel, Melanie J. B.; Anderegg, William R. L.

Widespread tree mortality associated with drought has been observed on all forested continents, and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water, and energy balance, and is poorly represented in dynamic vegetation models. Reducing uncertainty requires improved mortality projections founded on robust physiological processes. However, the proposed mechanisms of drought-induced mortality, including hydraulic failure and carbon starvation, are unresolved. A growing number of empirical studies have investigated these mechanisms, but data have not been consistently analyzed across species and biomes using a standardized physiological framework. Here we show thatmore » xylem hydraulic failure was ubiquitous across multiple tree taxa at drought-induced mortality. All species assessed had 60% or greater loss of xylem hydraulic conductivity, consistent with proposed theoretical and modelled survival thresholds. We found diverse responses in non-structural carbohydrates at mortality, indicating that evidence supporting carbon starvation was not universal. Reduced non-structural carbohydrates were more common for gymnosperms than angiosperms, associated with xylem hydraulic vulnerability, and may have a role in hydraulic deterioration. The consistent Our finding that across species of hydraulic failure at drought-induced mortality was persistent across species indicates that substantial improvement in vegetation modelling can be achieved using thresholds in hydraulic function.« less

Structure and function of gap junction proteins: role of gap junction proteins in embryonic heart development.

PubMed

Ahir, Bhavesh K; Pratten, Margaret K

2014-01-01

Intercellular (cell-to-cell) communication is a crucial and complex mechanism during embryonic heart development. In the cardiovascular system, the beating of the heart is a dynamic and key regulatory process, which is functionally regulated by the coordinated spread of electrical activity through heart muscle cells. Heart tissues are composed of individual cells, each bearing specialized cell surface membrane structures called gap junctions that permit the intercellular exchange of ions and low molecular weight molecules. Gap junction channels are essential in normal heart function and they assist in the mediated spread of electrical impulses that stimulate synchronized contraction (via an electrical syncytium) of cardiac tissues. This present review describes the current knowledge of gap junction biology. In the first part, we summarise some relevant biochemical and physiological properties of gap junction proteins, including their structure and function. In the second part, we review the current evidence demonstrating the role of gap junction proteins in embryonic development with particular reference to those involved in embryonic heart development. Genetics and transgenic animal studies of gap junction protein function in embryonic heart development are considered and the alteration/disruption of gap junction intercellular communication which may lead to abnormal heart development is also discussed.

Physiological Implications of Myocardial Scar Structure

PubMed Central

Richardson, WJ; Clarke, SA; Quinn, TA; Holmes, JW

2016-01-01

Once myocardium dies during a heart attack, it is replaced by scar tissue over the course of several weeks. The size, location, composition, structure and mechanical properties of the healing scar are all critical determinants of the fate of patients who survive the initial infarction. While the central importance of scar structure in determining pump function and remodeling has long been recognized, it has proven remarkably difficult to design therapies that improve heart function or limit remodeling by modifying scar structure. Many exciting new therapies are under development, but predicting their long-term effects requires a detailed understanding of how infarct scar forms, how its properties impact left ventricular function and remodeling, and how changes in scar structure and properties feed back to affect not only heart mechanics but also electrical conduction, reflex hemodynamic compensations, and the ongoing process of scar formation itself. In this article, we outline the scar formation process following an MI, discuss interpretation of standard measures of heart function in the setting of a healing infarct, then present implications of infarct scar geometry and structure for both mechanical and electrical function of the heart and summarize experiences to date with therapeutic interventions that aim to modify scar geometry and structure. One important conclusion that emerges from the studies reviewed here is that computational modeling is an essential tool for integrating the wealth of information required to understand this complex system and predict the impact of novel therapies on scar healing, heart function, and remodeling following myocardial infarction. PMID:26426470

Oxidant/Antioxidant Balance in Animal Nutrition and Health: The Role of Protein Oxidation

PubMed Central

Celi, Pietro; Gabai, Gianfranco

2015-01-01

This review examines the role that oxidative stress (OS), and protein oxidation in particular, plays in nutrition, metabolism, and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional modifications. Protein oxidation seems to be involved in pathological conditions, such as respiratory diseases and parasitic infection; however, some studies also suggest that protein oxidation plays a crucial role in the regulation of important physiological functions, such as reproduction, nutrition, metabolism, lactation, gut health, and neonatal physiology. As the characterization of the mechanisms by which OS may influence metabolism and health is attracting considerable scientific interest, the aim of this review is to present veterinary scientists and clinicians with various aspects of oxidative damage to proteins. PMID:26664975

ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies

PubMed Central

Poroca, Diogo R.; Pelis, Ryan M.; Chappe, Valérie M.

2017-01-01

The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl- transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl- ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms. ClC proteins form transmembrane dimers, in which each monomer displays independent ion conductance. Eukaryotic members also possess a large cytoplasmic domain containing two CBS domains, which are involved in transport modulation. ClC proteins function as either Cl- channels or Cl-/H+ exchangers, although all ClC proteins share the same basic architecture. ClC channels have two gating mechanisms: a relatively well-studied fast gating mechanism, and a slow gating mechanism, which is poorly defined. ClCs are involved in a wide range of physiological processes, including regulation of resting membrane potential in skeletal muscle, facilitation of transepithelial Cl- reabsorption in kidneys, and control of pH and Cl- concentration in intracellular compartments through coupled Cl-/H+ exchange mechanisms. Several inherited diseases result from C1C gene mutations, including myotonia congenita, Bartter’s syndrome (types 3 and 4), Dent’s disease, osteopetrosis, retinal degeneration, and lysosomal storage diseases. This review summarizes general features, known or suspected, of ClC structure, gating and physiological functions. We also discuss biophysical properties of mammalian ClCs that are directly involved in the pathophysiology of several human inherited disorders, or that induce interesting phenotypes in animal models. PMID:28386229

Deciphering structural and functional roles of individual disulfide bonds of the mitochondrial sulfhydryl oxidase Erv1p.

PubMed

Ang, Swee Kim; Lu, Hui

2009-10-16

Erv1p is a FAD-dependent sulfhydryl oxidase of the mitochondrial intermembrane space. It contains three conserved disulfide bonds arranged in two CXXC motifs and one CX(16)C motif. Experimental evidence for the specific roles of the individual disulfide bonds is lacking. In this study, structural and functional roles of the disulfides were dissected systematically using a wide range of biochemical and biophysical methods. Three double cysteine mutants with each pair of cysteines mutated to serines were generated. All of the mutants were purified with the normal FAD binding properties as the wild type Erv1p, showing that none of the three disulfides are essential for FAD binding. Thermal denaturation and trypsin digestion studies showed that the CX(16)C disulfide plays an important role in stabilizing the folding of Erv1p. To understand the functional role of each disulfide, small molecules and the physiological substrate protein Mia40 were used as electron donors in oxygen consumption assays. We show that both CXXC disulfides are required for Erv1 oxidase activity. The active site disulfide is well protected thus requires the shuttle disulfide for its function. Although both mutants of the CXXC motifs were individually inactive, Erv1p activity was partially recovered by mixing these two mutants together, and the recovery was rapid. Thus, we provided the first experimental evidence of electron transfer between the shuttle and active site disulfides of Erv1p, and we propose that both intersubunit and intermolecular electron transfer can occur.

Deciphering Structural and Functional Roles of Individual Disulfide Bonds of the Mitochondrial Sulfhydryl Oxidase Erv1p*

PubMed Central

Ang, Swee Kim; Lu, Hui

2009-01-01

Erv1p is a FAD-dependent sulfhydryl oxidase of the mitochondrial intermembrane space. It contains three conserved disulfide bonds arranged in two CXXC motifs and one CX16C motif. Experimental evidence for the specific roles of the individual disulfide bonds is lacking. In this study, structural and functional roles of the disulfides were dissected systematically using a wide range of biochemical and biophysical methods. Three double cysteine mutants with each pair of cysteines mutated to serines were generated. All of the mutants were purified with the normal FAD binding properties as the wild type Erv1p, showing that none of the three disulfides are essential for FAD binding. Thermal denaturation and trypsin digestion studies showed that the CX16C disulfide plays an important role in stabilizing the folding of Erv1p. To understand the functional role of each disulfide, small molecules and the physiological substrate protein Mia40 were used as electron donors in oxygen consumption assays. We show that both CXXC disulfides are required for Erv1 oxidase activity. The active site disulfide is well protected thus requires the shuttle disulfide for its function. Although both mutants of the CXXC motifs were individually inactive, Erv1p activity was partially recovered by mixing these two mutants together, and the recovery was rapid. Thus, we provided the first experimental evidence of electron transfer between the shuttle and active site disulfides of Erv1p, and we propose that both intersubunit and intermolecular electron transfer can occur. PMID:19679655

Fitting C 2 Continuous Parametric Surfaces to Frontiers Delimiting Physiologic Structures

PubMed Central

Bayer, Jason D.

2014-01-01

We present a technique to fit C 2 continuous parametric surfaces to scattered geometric data points forming frontiers delimiting physiologic structures in segmented images. Such mathematical representation is interesting because it facilitates a large number of operations in modeling. While the fitting of C 2 continuous parametric curves to scattered geometric data points is quite trivial, the fitting of C 2 continuous parametric surfaces is not. The difficulty comes from the fact that each scattered data point should be assigned a unique parametric coordinate, and the fit is quite sensitive to their distribution on the parametric plane. We present a new approach where a polygonal (quadrilateral or triangular) surface is extracted from the segmented image. This surface is subsequently projected onto a parametric plane in a manner to ensure a one-to-one mapping. The resulting polygonal mesh is then regularized for area and edge length. Finally, from this point, surface fitting is relatively trivial. The novelty of our approach lies in the regularization of the polygonal mesh. Process performance is assessed with the reconstruction of a geometric model of mouse heart ventricles from a computerized tomography scan. Our results show an excellent reproduction of the geometric data with surfaces that are C 2 continuous. PMID:24782911

Interspecies physiological variation as a tool for cross-species assessments of global warming-induced endangerment: validation of an intrinsic determinant of macroecological and phylogeographic structure.

PubMed

Bernardo, Joseph; Ossola, Ryan J; Spotila, James; Crandall, Keith A

2007-12-22

Global warming is now recognized as the dominant threat to biodiversity because even protected populations and habitats are susceptible. Nonetheless, current criteria for evaluating species' relative endangerment remain purely ecological, and the accepted conservation strategies of habitat preservation and population management assume that species can mount ecological responses if afforded protection. The insidious threat from climate change is that it will attenuate or preclude ecological responses by species that are physiologically constrained; yet, quantitative, objective criteria for assessing relative susceptibility of diverse taxa to warming-induced stress are wanting. We explored the utility of using interspecies physiological variation for this purpose by relating species' physiological phenotypes to landscape patterns of ecological and genetic exchange. Using a salamander model system in which ecological, genetic and physiological diversity are well characterized, we found strong quantitative relationships of basal metabolic rates (BMRs) to both macroecological and phylogeographic patterns, with decreasing BMR leading to dispersal limitation (small contemporary ranges with marked phylogeographic structure). Measures of intrinsic physiological tolerance, which vary systematically with macroecological and phylogeographic patterns, afford objective criteria for assessing endangerment across a wide range of species and should be incorporated into conservation assessment criteria that currently rely exclusively upon ecological predictors.

Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices

NASA Astrophysics Data System (ADS)

Stagakis, S.; González-Dugo, V.; Cid, P.; Guillén-Climent, M. L.; Zarco-Tejada, P. J.

2012-07-01

This paper deals with the monitoring of water status and the assessment of the effect of stress on citrus fruit quality using structural and physiological remote sensing indices. Four flights were conducted over a citrus orchard in 2009 using an unmanned aerial vehicle (UAV) carrying a multispectral camera with six narrow spectral bands in the visible and near infrared. Physiological indices such as the Photochemical Reflectance Index (PRI570), a new structurally robust PRI formulation that uses the 515 nm as the reference band (PRI515), and a chlorophyll ratio (R700/R670) were compared against the Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI) and Modified Triangular Vegetation Index (MTVI) canopy structural indices for their performance in tracking water status and the effects of sustained water stress on fruit quality at harvest. The irrigation setup in the commercial orchard was compared against a treatment scheduled to satisfy full requirements (based on estimated crop evapotranspiration) using two regulated deficit irrigation (RDI) strategies. The water status of the trees throughout the experiment was monitored with frequent field measurements of stem water potential (Ψx), while titratable acidity (TA) and total soluble solids (TSS) were measured at harvest on selected trees from each irrigation treatment. The high spatial resolution of the multispectral imagery (30 cm pixel size) enabled identification of pure tree crown components, extracting the tree reflectance from shaded, sunlit and aggregated pixels. The physiological and structural indices were then calculated from each tree at the following levels: (i) pure sunlit tree crown, (ii) entire crown, aggregating the within-crown shadows, and (iii) simulating a lower resolution pixel, including tree crown, sunlit and shaded soil pixels. The resulting analysis demonstrated that both PRI formulations were able to track water status, except when water stress

p21Cip1 plays a critical role in the physiological adaptation to fasting through activation of PPARα.

PubMed

Lopez-Guadamillas, Elena; Fernandez-Marcos, Pablo J; Pantoja, Cristina; Muñoz-Martin, Maribel; Martínez, Dolores; Gómez-López, Gonzalo; Campos-Olivas, Ramón; Valverde, Angela M; Serrano, Manuel

2016-10-10

Fasting is a physiological stress that elicits well-known metabolic adaptations, however, little is known about the role of stress-responsive tumor suppressors in fasting. Here, we have examined the expression of several tumor suppressors upon fasting in mice. Interestingly, p21 mRNA is uniquely induced in all the tissues tested, particularly in liver and muscle (>10 fold), and this upregulation is independent of p53. Remarkably, in contrast to wild-type mice, p21-null mice become severely morbid after prolonged fasting. The defective adaptation to fasting of p21-null mice is associated to elevated energy expenditure, accelerated depletion of fat stores, and premature activation of protein catabolism in the muscle. Analysis of the liver transcriptome and cell-based assays revealed that the absence of p21 partially impairs the transcriptional program of PPARα, a key regulator of fasting metabolism. Finally, treatment of p21-null mice with a PPARα agonist substantially protects them from their accelerated loss of fat upon fasting. We conclude that p21 plays a relevant role in fasting adaptation through the positive regulation of PPARα.

Integrating knowledge representation and quantitative modelling in physiology.

PubMed

de Bono, Bernard; Hunter, Peter

2012-08-01

A wealth of potentially shareable resources, such as data and models, is being generated through the study of physiology by computational means. Although in principle the resources generated are reusable, in practice, few can currently be shared. A key reason for this disparity stems from the lack of consistent cataloguing and annotation of these resources in a standardised manner. Here, we outline our vision for applying community-based modelling standards in support of an automated integration of models across physiological systems and scales. Two key initiatives, the Physiome Project and the European contribution - the Virtual Phsysiological Human Project, have emerged to support this multiscale model integration, and we focus on the role played by two key components of these frameworks, model encoding and semantic metadata annotation. We present examples of biomedical modelling scenarios (the endocrine effect of atrial natriuretic peptide, and the implications of alcohol and glucose toxicity) to illustrate the role that encoding standards and knowledge representation approaches, such as ontologies, could play in the management, searching and visualisation of physiology models, and thus in providing a rational basis for healthcare decisions and contributing towards realising the goal of of personalized medicine. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Demand for interdisciplinary laboratories for physiology research by undergraduate students in biosciences and biomedical engineering.

PubMed

Clase, Kari L; Hein, Patrick W; Pelaez, Nancy J

2008-12-01

Physiology as a discipline is uniquely positioned to engage undergraduate students in interdisciplinary research in response to the 2006-2011 National Science Foundation Strategic Plan call for innovative transformational research, which emphasizes multidisciplinary projects. To prepare undergraduates for careers that cross disciplinary boundaries, students need to practice interdisciplinary communication in academic programs that connect students in diverse disciplines. This report surveys policy documents relevant to this emphasis on interdisciplinary training and suggests a changing role for physiology courses in bioscience and engineering programs. A role for a physiology course is increasingly recommended for engineering programs, but the study of physiology from an engineering perspective might differ from the study of physiology as a basic science. Indeed, physiology laboratory courses provide an arena where biomedical engineering and bioscience students can apply knowledge from both fields while cooperating in multidisciplinary teams under specified technical constraints. Because different problem-solving approaches are used by students of engineering and bioscience, instructional innovations are needed to break down stereotypes between the disciplines and create an educational environment where interdisciplinary teamwork is used to bridge differences.

A model for the solution structure of the rod arrestin tetramer.

PubMed

Hanson, Susan M; Dawson, Eric S; Francis, Derek J; Van Eps, Ned; Klug, Candice S; Hubbell, Wayne L; Meiler, Jens; Gurevich, Vsevolod V

2008-06-01

Visual rod arrestin has the ability to self-associate at physiological concentrations. We previously demonstrated that only monomeric arrestin can bind the receptor and that the arrestin tetramer in solution differs from that in the crystal. We employed the Rosetta docking software to generate molecular models of the physiologically relevant solution tetramer based on the monomeric arrestin crystal structure. The resulting models were filtered using the Rosetta energy function, experimental intersubunit distances measured with DEER spectroscopy, and intersubunit contact sites identified by mutagenesis and site-directed spin labeling. This resulted in a unique model for subsequent evaluation. The validity of the model is strongly supported by model-directed crosslinking and targeted mutagenesis that yields arrestin variants deficient in self-association. The structure of the solution tetramer explains its inability to bind rhodopsin and paves the way for experimental studies of the physiological role of rod arrestin self-association.

On the Physiological Modulation and Potential Mechanisms Underlying Parieto-Occipital Alpha Oscillations

PubMed Central

Lozano-Soldevilla, Diego

2018-01-01

The parieto-occipital alpha (8–13 Hz) rhythm is by far the strongest spectral fingerprint in the human brain. Almost 90 years later, its physiological origin is still far from clear. In this Research Topic I review human pharmacological studies using electroencephalography (EEG) and magnetoencephalography (MEG) that investigated the physiological mechanisms behind posterior alpha. Based on results from classical and recent experimental studies, I find a wide spectrum of drugs that modulate parieto-occipital alpha power. Alpha frequency is rarely affected, but this might be due to the range of drug dosages employed. Animal and human pharmacological findings suggest that both GABA enhancers and NMDA blockers systematically decrease posterior alpha power. Surprisingly, most of the theoretical frameworks do not seem to embrace these empirical findings and the debate on the functional role of alpha oscillations has been polarized between the inhibition vs. active poles hypotheses. Here, I speculate that the functional role of alpha might depend on physiological excitation as much as on physiological inhibition. This is supported by animal and human pharmacological work showing that GABAergic, glutamatergic, cholinergic, and serotonergic receptors in the thalamus and the cortex play a key role in the regulation of alpha power and frequency. This myriad of physiological modulations fit with the view that the alpha rhythm is a complex rhythm with multiple sources supported by both thalamo-cortical and cortico-cortical loops. Finally, I briefly discuss how future research combining experimental measurements derived from theoretical predictions based of biophysically realistic computational models will be crucial to the reconciliation of these disparate findings. PMID:29670518

Neutrophil-derived cytokines involved in physiological and pathological angiogenesis.

PubMed

Tecchio, Cristina; Cassatella, Marco Antonio

2014-01-01

Increasing data from the literature point to a neutrophil-mediated role via cytokine production in several aspects of mammalian biology, including angiogenesis. In such regard, neutrophils have been shown to synthetize and release a number of molecules able to promote, directly or indirectly, the growth and migration of endothelial cells, in turn inducing the formation of new blood vessels from preexisting ones. Interestingly, neutrophil-derived cytokines can be involved either in physiological or in pathological angiogenesis, depending on either the functioning or dysregulation of sophisticated interplays among different cell types, extracellular matrix and soluble mediators within the microenvironment. Our review resumes the most interesting studies elucidating the role of neutrophil-derived cytokines in human physiological and pathological angiogenesis. When appropriate, supporting observations generated in animal models will be also mentioned. Particular emphasis will be given to VEGF and PK2/Bv8, rather than CXCL8/IL-8 and OSM. We will also discuss the potential role of neutrophil-derived cytokines such as FGF2, Ang1 and IL-17, whose roles in angiogenesis - albeit anticipated - remain to be elucidated. Copyright © 2014 S. Karger AG, Basel.

Pleiotropic role of the Sco1/SenC family copper chaperone in the physiology of Streptomyces

PubMed Central

Fujimoto, Masahiro; Yamada, Akio; Kurosawa, Junpei; Kawata, Akihiro; Beppu, Teruhiko; Takano, Hideaki; Ueda, Kenji

2012-01-01

Summary Antibiotic production and cell differentiation in Streptomyces is stimulated by micromolar levels of Cu2+. Here, we knocked out the Sco1/SenC family copper chaperone (ScoC) encoded in the conserved gene cluster ‘sco’ (the S treptomycescopper utilization) in Streptomyces coelicolor A3(2) and S. griseus. It is known that the Sco1/SenC family incorporates Cu2+ into the active centre of cytochrome oxidase (cox). The knockout caused a marked delay in antibiotic production and aerial mycelium formation on solid medium, temporal pH decline in glucose‐containing liquid medium, and significant reduction of cox activity in S. coelicolor. The scoC mutant produced two‐ to threefold higher cellular mass of the wild type exhibiting a marked cox activity in liquid medium supplied with 10 µM CuSO4, suggesting that ScoC is involved in not only the construction but also the deactivation of cox. The scoC mutant was defective in the monoamine oxidase activity responsible for cell aggregation and sedimentation. These features were similarly observed with regard to the scoC mutant of S. griseus. The scoC mutant of S. griseus was also defective in the extracellular activity oxidizing N,N′‐dimethyl‐p‐phenylenediamine sulfate. Addition of 10 µM CuSO4 repressed the activity of the conserved promoter preceding scoA and caused phenylalanine auxotrophy in some Streptomyces spp. probably because of the repression of pheA; pheA encodes prephenate dehydratase, which is located at the 3′ terminus of the putative operon structure. Overall, the evidence indicates that Sco is crucial for the utilization of copper under a low‐copper condition and for the activation of the multiple Cu2+‐containing oxidases that play divergent roles in the complex physiology of Streptomyces. PMID:22117562

The role of structural parameters in DNA cyclization

DOE PAGES

Alexandrov, Ludmil B.; Bishop, Alan R.; Rasmussen, Kim O.; ...

2016-02-04

The intrinsic bendability of DNA plays an important role with relevance for myriad of essential cellular mechanisms. The flexibility of a DNA fragment can be experimentally and computationally examined by its propensity for cyclization, quantified by the Jacobson-Stockmayer J factor. In this paper, we use a well-established coarse-grained three-dimensional model of DNA and seven distinct sets of experimentally and computationally derived conformational parameters of the double helix to evaluate the role of structural parameters in calculating DNA cyclization.

Journal of Gravitational Physiology, Volume 13, No. 1

NASA Technical Reports Server (NTRS)

Fuller, Charles A. (Editor); Cogoli, Augusto (Editor); Hargens, Alan R. (Editor); Smith, Arthur H. (Editor)

2006-01-01

At the outset, the Journal published one issue in 1994. The first number comprised the Proceedings of the 15th Annual International Gravitational Physiology Meeting, held in Barcelona, Spain in October 1993. The Proceedings of the previous 14 Annual Meetings appeared as supplements to The Physiologist from 1979 to 1993. Each year, one issue of the Journal is devoted to the Annual Meeting Proceedings, and up to four more issues are comprised of full-length research papers. Additionally, Supplement Issues are considered by the Editorial Board as they are submitted. The Journal is published for the International Society for Gravitational Physiology by the Galileo Foundation, a 501(c)(3) nonprofit public benefit corporation. This issue, the first number of 2006, comprises the Proceedings of the joint meeting of the International Society for Gravitational Physiology s 27th Annual International Gravitational Physiology Meeting, held in Osaka, Japan 23- 28 April, 2006. The Journal of Gravitational Physiology invites the submission of original experimental or observational papers on subjects in the field of gravitational physiology. Review articles, theoretical papers and historical or biographical articles will also be solicited by the Editor for publication. The wide scientific span of the Journal rests on physiology as its keystone. Gravitational physiology is considered to include the effects of changes in the magnitude and directions of the gravitational force environment on cells and physiological systems and behavior of humans, animals and plants. The effects of weightlessness during space flight, high sustained G forces and chronic acceleration, vibration, impact and the various forms of simulated weightlessness are also included, as well as is consideration of the evolutionary consequences of gravity and the role of gravity in the manifestation of scale effects in animals and plants.

The concept of function in modern physiology.

PubMed

Roux, Etienne

2014-06-01

An overview of the scientific literature shows that the concept of function is central in physiology. However, the concept itself is not defined by physiologists. On the other hand, the teleological, namely, the 'goal-directed' dimension of function, and its subsequent explanatory relevance, is a philosophical problem. Intuitively, the function of a trait in a system explains why this trait is present, but, in the early 1960s, Ernest Nagel and Carl Hempel have shown that this inference cannot be logically founded. However, they showed that self-regulated systems are teleological. According to the selectionist theories, the function of an item is its effect that has been selected by natural selection, a process that explains its presence. As they restrict the functional attribution of a trait to its past selective value and not its current properties, these theories are inconsistent with the concept of function in physiology. A more adequate one is the causal role theory, for which a function of a trait in a system is its causal contribution to the functional capacity of the system. However, this leaves unsolved the question of the 'surplus meaning' of the teleological dimension of function. The significance of considering organisms as 'purpose-like' (teleological) systems may reside not in its explanatory power but in its methodological fruitfulness in physiology. In this view, the teleological dimension of physiological functions is convergent to but not imported from, the teleological dimension of evolutionary biology. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

The Physiology of Fear: Reconceptualizing the Role of the Central Amygdala in Fear Learning.

PubMed

Keifer, Orion P; Hurt, Robert C; Ressler, Kerry J; Marvar, Paul J

2015-09-01

The historically understood role of the central amygdala (CeA) in fear learning is to serve as a passive output station for processing and plasticity that occurs elsewhere in the brain. However, recent research has suggested that the CeA may play a more dynamic role in fear learning. In particular, there is growing evidence that the CeA is a site of plasticity and memory formation, and that its activity is subject to tight regulation. The following review examines the evidence for these three main roles of the CeA as they relate to fear learning. The classical role of the CeA as a routing station to fear effector brain structures like the periaqueductal gray, the lateral hypothalamus, and paraventricular nucleus of the hypothalamus will be briefly reviewed, but specific emphasis is placed on recent literature suggesting that the CeA 1) has an important role in the plasticity underlying fear learning, 2) is involved in regulation of other amygdala subnuclei, and 3) is itself regulated by intra- and extra-amygdalar input. Finally, we discuss the parallels of human and mouse CeA involvement in fear disorders and fear conditioning, respectively. ©2015 Int. Union Physiol. Sci./Am. Physiol. Soc.

Structure, and culture of the gut microbiome of the Mormon cricket Anabrus simplex

USDA-ARS?s Scientific Manuscript database

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the n...

Roles of NN-interaction components in shell-structure evolution

NASA Astrophysics Data System (ADS)

Umeya, Atsushi; Muto, Kazuo

2016-11-01

Since the importance of the monopole interaction was first emphasized in 1960s, roles of monopole strengths of two-body nucleon-nucleon interaction in shell structure have been discussed. Through the monopole strengths, we study the roles in shell-structure evolution, starting from explicit forms of the interaction. For the tensor component of the interaction, we show the derivation of the relation, (2j> + 1)Vjj> + (2j< + 1)Vjj< = 0, with a detailed manipulation. We show that one-body spin-orbit term appears in the multipole expansion of two-body spin-orbit interaction. Only the spin-orbit components can affect the spin-orbit energy splitting between spin-orbit partners, when the spin-orbit partner orbits are fully occupied.

Conservation physiology for applied management of marine fish: an overview with perspectives on the role and value of telemetry

PubMed Central

Metcalfe, J. D.; Le Quesne, W. J. F.; Cheung, W. W. L.; Righton, D. A.

2012-01-01

Physiological studies focus on the responses of cells, tissues and individuals to stressors, usually in laboratory situations. Conservation and management, on the other hand, focus on populations. The field of conservation physiology addresses the question of how abiotic drivers of physiological responses at the level of the individual alter requirements for successful conservation and management of populations. To achieve this, impacts of physiological effects at the individual level need to be scaled to impacts on population dynamics, which requires consideration of ecology. Successfully realizing the potential of conservation physiology requires interdisciplinary studies incorporating physiology and ecology, and requires that a constructive dialogue develops between these traditionally disparate fields. To encourage this dialogue, we consider the increasingly explicit incorporation of physiology into ecological models applied to marine fish conservation and management. Conservation physiology is further challenged as the physiology of an individual revealed under laboratory conditions is unlikely to reflect realized responses to the complex variable stressors to which it is exposed in the wild. Telemetry technology offers the capability to record an animal's behaviour while simultaneously recording environmental variables to which it is exposed. We consider how the emerging insights from telemetry can strengthen the incorporation of physiology into ecology. PMID:22566680

Regulating plant physiology with organic electronics.

PubMed

Poxson, David J; Karady, Michal; Gabrielsson, Roger; Alkattan, Aziz Y; Gustavsson, Anna; Doyle, Siamsa M; Robert, Stéphanie; Ljung, Karin; Grebe, Markus; Simon, Daniel T; Berggren, Magnus

2017-05-02

The organic electronic ion pump (OEIP) provides flow-free and accurate delivery of small signaling compounds at high spatiotemporal resolution. To date, the application of OEIPs has been limited to delivery of nonaromatic molecules to mammalian systems, particularly for neuroscience applications. However, many long-standing questions in plant biology remain unanswered due to a lack of technology that precisely delivers plant hormones, based on cyclic alkanes or aromatic structures, to regulate plant physiology. Here, we report the employment of OEIPs for the delivery of the plant hormone auxin to induce differential concentration gradients and modulate plant physiology. We fabricated OEIP devices based on a synthesized dendritic polyelectrolyte that enables electrophoretic transport of aromatic substances. Delivery of auxin to transgenic Arabidopsis thaliana seedlings in vivo was monitored in real time via dynamic fluorescent auxin-response reporters and induced physiological responses in roots. Our results provide a starting point for technologies enabling direct, rapid, and dynamic electronic interaction with the biochemical regulation systems of plants.

Regulating plant physiology with organic electronics

PubMed Central

Poxson, David J.; Karady, Michal; Alkattan, Aziz Y.; Gustavsson, Anna; Robert, Stéphanie; Grebe, Markus; Berggren, Magnus

2017-01-01

The organic electronic ion pump (OEIP) provides flow-free and accurate delivery of small signaling compounds at high spatiotemporal resolution. To date, the application of OEIPs has been limited to delivery of nonaromatic molecules to mammalian systems, particularly for neuroscience applications. However, many long-standing questions in plant biology remain unanswered due to a lack of technology that precisely delivers plant hormones, based on cyclic alkanes or aromatic structures, to regulate plant physiology. Here, we report the employment of OEIPs for the delivery of the plant hormone auxin to induce differential concentration gradients and modulate plant physiology. We fabricated OEIP devices based on a synthesized dendritic polyelectrolyte that enables electrophoretic transport of aromatic substances. Delivery of auxin to transgenic Arabidopsis thaliana seedlings in vivo was monitored in real time via dynamic fluorescent auxin-response reporters and induced physiological responses in roots. Our results provide a starting point for technologies enabling direct, rapid, and dynamic electronic interaction with the biochemical regulation systems of plants. PMID:28420793

Tropomodulin Capping of Actin Filaments in Striated Muscle Development and Physiology

PubMed Central

Gokhin, David S.; Fowler, Velia M.

2011-01-01

Efficient striated muscle contraction requires precise assembly and regulation of diverse actin filament systems, most notably the sarcomeric thin filaments of the contractile apparatus. By capping the pointed ends of actin filaments, tropomodulins (Tmods) regulate actin filament assembly, lengths, and stability. Here, we explore the current understanding of the expression patterns, localizations, and functions of Tmods in both cardiac and skeletal muscle. We first describe the mechanisms by which Tmods regulate myofibril assembly and thin filament lengths, as well as the roles of closely related Tmod family variants, the leiomodins (Lmods), in these processes. We also discuss emerging functions for Tmods in the sarcoplasmic reticulum. This paper provides abundant evidence that Tmods are key structural regulators of striated muscle cytoarchitecture and physiology. PMID:22013379

An integrated physiology model to study regional lung damage effects and the physiologic response

PubMed Central

2014-01-01

Background This work expands upon a previously developed exercise dynamic physiology model (DPM) with the addition of an anatomic pulmonary system in order to quantify the impact of lung damage on oxygen transport and physical performance decrement. Methods A pulmonary model is derived with an anatomic structure based on morphometric measurements, accounting for heterogeneous ventilation and perfusion observed experimentally. The model is incorporated into an existing exercise physiology model; the combined system is validated using human exercise data. Pulmonary damage from blast, blunt trauma, and chemical injury is quantified in the model based on lung fluid infiltration (edema) which reduces oxygen delivery to the blood. The pulmonary damage component is derived and calibrated based on published animal experiments; scaling laws are used to predict the human response to lung injury in terms of physical performance decrement. Results The augmented dynamic physiology model (DPM) accurately predicted the human response to hypoxia, altitude, and exercise observed experimentally. The pulmonary damage parameters (shunt and diffusing capacity reduction) were fit to experimental animal data obtained in blast, blunt trauma, and chemical damage studies which link lung damage to lung weight change; the model is able to predict the reduced oxygen delivery in damage conditions. The model accurately estimates physical performance reduction with pulmonary damage. Conclusions We have developed a physiologically-based mathematical model to predict performance decrement endpoints in the presence of thoracic damage; simulations can be extended to estimate human performance and escape in extreme situations. PMID:25044032

Phosphorylation of αB-crystallin: Role in stress, aging and patho-physiological conditions.

PubMed

Bakthisaran, Raman; Akula, Kranthi Kiran; Tangirala, Ramakrishna; Rao, Ch Mohan

2016-01-01

αB-crystallin, once thought to be a lenticular protein, is ubiquitous and has critical roles in several cellular processes that are modulated by phosphorylation. Serine residues 19, 45 and 59 of αB-crystallin undergo phosphorylation. Phosphorylation of S45 is mediated by p44/42 MAP kinase, whereas S59 phosphorylation is mediated by MAPKAP kinase-2. Pathway involved in S19 phosphorylation is not known. The review highlights the role of phosphorylation in (i) oligomeric structure, stability and chaperone activity, (ii) cellular processes such as apoptosis, myogenic differentiation, cell cycle regulation and angiogenesis, and (iii) aging, stress, cardiomyopathy-causing αB-crystallin mutants, and in other diseases. Depending on the context and extent of phosphorylation, αB-crystallin seems to confer beneficial or deleterious effects. Phosphorylation alters structure, stability, size distribution and dynamics of the oligomeric assembly, thus modulating chaperone activity and various cellular processes. Phosphorylated αB-crystallin has a tendency to partition to the cytoskeleton and hence to the insoluble fraction. Low levels of phosphorylation appear to be protective, while hyperphosphorylation has negative implications. Mutations in αB-crystallin, such as R120G, Q151X and 464delCT, associated with inherited myofibrillar myopathy lead to hyperphosphorylation and intracellular inclusions. An ongoing study in our laboratory with phosphorylation-mimicking mutants indicates that phosphorylation of R120GαB-crystallin increases its propensity to aggregate. Phosphorylation of αB-crystallin has dual role that manifests either beneficial or deleterious consequences depending on the extent of phosphorylation and interaction with cytoskeleton. Considering that disease-causing mutants of αB-crystallin are hyperphosphorylated, moderation of phosphorylation may be a useful strategy in disease management. This article is part of a Special Issue entitled Crystallin

Platelets in pulmonary vascular physiology and pathology

PubMed Central

Kroll, Michael H.; Afshar-Kharghan, Vahid

2012-01-01

Almost a trillion platelets pass through the pulmonary circulation every minute, yet little is known about how they support pulmonary physiology or contribute to the pathogenesis of lung diseases. When considering this conundrum, three questions jump out: Does platelet production in the lungs occur? Why does severe thrombocytopenia—which undercuts the principal physiological role of platelets to effect hemostasis—not lead to pulmonary hemorrhage? Why does atherothrombosis—which platelets initiate, maintain, and trigger is other critically important arterial beds—not develop in the pulmonary artery? The purpose of this review is to explore these and derivative questions by providing data within a conceptual framework that begins to organize a subject that is largely unassembled. PMID:23130099

The Central Endocrine Glands: Intertwining Physiology and Pharmacy

PubMed Central

2007-01-01

The initial courses in didactic pharmacy curriculum are designed to provide core scientific knowledge and develop learning skills that are the basis for highly competent application and practice of pharmacy. Commonly, students interpret this scientific base as ancillary to the practice of pharmacy. Physiology courses present a natural opportunity for the instructor to introduce basic pharmaceutical principles that form the foundation of pharmacological application early in the professional curriculum. Human Physiology I is the first of a 2-course physiology sequence that pharmacy students take upon matriculating into Midwestern University College of Pharmacy-Glendale. The endocrine physiology section of this course is designed to emphasize the regulatory and compensatory nature of this system in maintaining homeostasis, but also includes aspects of basic pharmaceutical principles. In this way the dependency of physiology and pharmacy upon one another is accentuated. The lecture format and content described in this manuscript focus on the central endocrine glands and illustrates their vital role in normal body function, compensatory responses to disease states, and their components as pharmacotherapy targets. The integration of these pharmaceutical principles at the introductory level supports an environment that can alleviate any perceived disparity between science foundation and practical application in the profession of pharmacy. PMID:17998993

Use of Concept Mapping in an Undergraduate Introductory Exercise Physiology Course

ERIC Educational Resources Information Center

Henige, Kim

2012-01-01

Physiology is often considered a challenging course for students. It is up to teachers to structure courses and create learning opportunities that will increase the chance of student success. In an undergraduate exercise physiology course, concept maps are assigned to help students actively process and organize information into manageable and…

Defence mechanisms: the role of physiology in current and future environmental protection paradigms

PubMed Central

Glover, Chris N

2018-01-01

Abstract Ecological risk assessments principally rely on simplified metrics of organismal sensitivity that do not consider mechanism or biological traits. As such, they are unable to adequately extrapolate from standard laboratory tests to real-world settings, and largely fail to account for the diversity of organisms and environmental variables that occur in natural environments. However, an understanding of how stressors influence organism health can compensate for these limitations. Mechanistic knowledge can be used to account for species differences in basal biological function and variability in environmental factors, including spatial and temporal changes in the chemical, physical and biological milieu. Consequently, physiological understanding of biological function, and how this is altered by stressor exposure, can facilitate proactive, predictive risk assessment. In this perspective article, existing frameworks that utilize physiological knowledge (e.g. biotic ligand models, adverse outcomes pathways and mechanistic effect models), are outlined, and specific examples of how mechanistic understanding has been used to predict risk are highlighted. Future research approaches and data needs for extending the incorporation of physiological information into ecological risk assessments are discussed. Although the review focuses on chemical toxicants in aquatic systems, physical and biological stressors and terrestrial environments are also briefly considered. PMID:29564135

Manipulating neural activity in physiologically classified neurons: triumphs and challenges

PubMed Central

Gore, Felicity; Schwartz, Edmund C.; Salzman, C. Daniel

2015-01-01

Understanding brain function requires knowing both how neural activity encodes information and how this activity generates appropriate responses. Electrophysiological, imaging and immediate early gene immunostaining studies have been instrumental in identifying and characterizing neurons that respond to different sensory stimuli, events and motor actions. Here we highlight approaches that have manipulated the activity of physiologically classified neurons to determine their role in the generation of behavioural responses. Previous experiments have often exploited the functional architecture observed in many cortical areas, where clusters of neurons share response properties. However, many brain structures do not exhibit such functional architecture. Instead, neurons with different response properties are anatomically intermingled. Emerging genetic approaches have enabled the identification and manipulation of neurons that respond to specific stimuli despite the lack of discernable anatomical organization. These approaches have advanced understanding of the circuits mediating sensory perception, learning and memory, and the generation of behavioural responses by providing causal evidence linking neural response properties to appropriate behavioural output. However, significant challenges remain for understanding cognitive processes that are probably mediated by neurons with more complex physiological response properties. Currently available strategies may prove inadequate for determining how activity in these neurons is causally related to cognitive behaviour. PMID:26240431

Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

PubMed

Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

2016-04-01

Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment. © 2015 John Wiley & Sons Ltd.

Polysaccharopeptides of Coriolus versicolor: physiological activity, uses, and production.

PubMed

Cui, Jian; Chisti, Yusuf

2003-04-01

The protein-bound polysaccharides or polysaccharopeptides produced by Coriolus versicolor are effective immunopotentiators, which are used to supplement the chemotherapy and radiotherapy of cancers and various infectious diseases. Antitumor activity of polysaccharopeptides has been documented. Several kinds of protein-bound polysaccharides have been shown to be produced by the white rot fungus, C. versicolor. Although some of these polymers are structurally distinct, they are not distinguishable in terms of their physiological activity. This review focuses on the physiologically active polysaccharopeptides of C. versicolor. In nature, C. versicolor occurs as a mushroom body, but the fungus can be grown as mycelial biomass in submerged culture in bioreactors. Mushrooms gathered in the wild, cultivated mushrooms, and the mycelial biomass of submerged culture are used to produce the polysaccharopeptides. Submerged cultures are typically carried out in batches lasting 5-7 days and at 25-27 degrees C. Hot water extraction of the biomass is used to recover the thermostable polysaccharopeptides that are concentrated, purified, and dried into a powder for medicinal use. In view of the documented physiological benefits of these compounds, extensive research is underway on the structure, composition, production methods, and use of new C. versicolor strains for producing the therapeutic biopolymers. Properties, physiological activity, recovery, and purification of the bioactive polysaccharopeptides are discussed.

Role Diffusion and Role Reversal: Structural Variations in Divorced Families and Children's Functioning.

ERIC Educational Resources Information Center

Johnston, Janet R.

1990-01-01

Tested model of family structure and process using 133 children where both divorced parents remained in children's lives about 3 years after separation. Found role diffusion, lack of coparental alliance, parental boundary problems, parent-child rejection associated with reduced social competence and behavioral difficulties (especially in boys and…

The Mediator complex of Caenorhabditis elegans: insights into the developmental and physiological roles of a conserved transcriptional coregulator.

PubMed

Grants, Jennifer M; Goh, Grace Y S; Taubert, Stefan

2015-02-27

The Mediator multiprotein complex ('Mediator') is an important transcriptional coregulator that is evolutionarily conserved throughout eukaryotes. Although some Mediator subunits are essential for the transcription of all protein-coding genes, others influence the expression of only subsets of genes and participate selectively in cellular signaling pathways. Here, we review the current knowledge of Mediator subunit function in the nematode Caenorhabditis elegans, a metazoan in which established and emerging genetic technologies facilitate the study of developmental and physiological regulation in vivo. In this nematode, unbiased genetic screens have revealed critical roles for Mediator components in core developmental pathways such as epidermal growth factor (EGF) and Wnt/β-catenin signaling. More recently, important roles for C. elegans Mediator subunits have emerged in the regulation of lipid metabolism and of systemic stress responses, engaging conserved transcription factors such as nuclear hormone receptors (NHRs). We emphasize instances where similar functions for individual Mediator subunits exist in mammals, highlighting parallels between Mediator subunit action in nematode development and in human cancer biology. We also discuss a parallel between the association of the Mediator subunit MED12 with several human disorders and the role of its C. elegans ortholog mdt-12 as a regulatory hub that interacts with numerous signaling pathways. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

The effects of high environmental ammonia on the structure of rainbow trout hierarchies and the physiology of the individuals therein.

PubMed

Grobler, Josias M B; Wood, Chris M

2018-02-01

Our goals were: (i) to determine whether sublethal concentrations of water-borne ammonia would prevent the formation of a dominance hierarchy, or alter its structure, in groups of 4 juvenile trout; (ii) to investigate the behavioral and physiological responses of individuals of different social rank exposed to a concentration of ammonia that still allowed hierarchy formation. Social hierarchies were created by using a technique in which a food delivery system that created competition also served to isolate individual fish for respirometry. Groups of 4 fish were exposed to elevated ammonia (NH 4 HCO 3 ) 12 h before first feeding; aggression was recorded by video camera during morning feedings. Experimental ammonia concentrations were 700, 1200 and 1500 μmol L -1 at pH 7.3, 12 °C (9.8, 16.8, and 21.0 mg L -1 as total ammonia-N, or 0.0515, 0.0884, and 0.1105 mg L -1 as NH 3 -N). Aggression was severely reduced by 1200 and abolished by 1500 μmol L -1 total ammonia, such that hierarchies did not form. However, groups exposed to 700 μmol L -1 total ammonia still formed stable hierarchies but displayed lower levels of aggression in comparison to control hierarchies. Exposure continued for 11 days. Physiological parameters were recorded on day 5 (end of period 1) and day 10 (end of period 2), while feeding and plasma cortisol were measured on day 11. In control hierarchies, dominant (rank 1) trout generally exhibited higher growth rates, greater increases in condition factor, higher food consumption, and lower cortisol levels than did fish of ranks 2, 3, and 4. In comparison to controls, the 700 μmol L -1 total ammonia hierarchies generally displayed lower growth, lower condition factor increases, lower O 2 consumption, lower cortisol levels, but similar feeding patterns, with smaller physiological differences amongst ranks during period 1. Effects attenuated during period 2, as aggression and physiological measures returned towards

Work Role Characteristics, Family Structure Demands, and Work/Family Conflict.

ERIC Educational Resources Information Center

Voydanoff, Patricia

1988-01-01

Examined relationships between work role characteristics, family structure demands, and work/family conflict, using data from 757 married men and 270 married women. Found that amount and scheduling of work time, job demands, and presence of children in home were related to work/family conflict. Work role characteristics and family structure…

A fluorescence resonance energy transfer (FRET)-based redox sensor reveals physiological role of thioredoxin in the yeast Saccharomyces cerevisiae.

PubMed

Oku, Masahide; Hoseki, Jun; Ichiki, Yayoi; Sakai, Yasuyoshi

2013-03-18

The physiological roles of the thioredoxin isozymes in the yeast Saccharomyces cerevisiae were investigated using a novel FRET-based redox probe, Redoxfluor. After establishing responsiveness of the probe toward thioredoxin, we followed the fluorescence signal of Redoxfluor expressed in the yeast and found that one of the thioredoxin isozymes, Trx2, was required for maintaining the redox status when stationary culture of the organism was exposed to starvation and mild-heat stresses. The failure to maintain redox balance under the tested condition preceded decreased viability of the trx2 mutants, indicating the functional importance of the cytoplasmic thioredoxin in adaptation to environmental changes. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Study of human serum albumin structure by dynamic light scattering: two types of reactions under different pH and interaction with physiologically active compounds

NASA Astrophysics Data System (ADS)

Luik, A. I.; Naboka, Yu. N.; Mogilevich, S. E.; Hushcha, T. O.; Mischenko, N. I.

1998-09-01

The effect of pH and binding of ten physiologically active compounds (isoproterenol, yohimbine, propranolol, clonidine, phenylephrine, carbachol, tripeptide fMLP, diphenhydramine, chlorpromazine and atropine) on the molecular structure of human serum albumin (HSA) has been studied using the dynamic light scattering. It was found that albumin globule has the most compact configuration (Stokes diameter 59-62 Å) at physiological pH 7.4. The changes in pH, both increase to 8.0 and decrease to 5.4, result in the growth of globule size to 72-81 Å. At acidic shift of pH an additional peak arises in the correlation spectra caused by the light scattering on the structures with the Stokes diameters of 29-37 Å. Those conform to the sizes of the albumin subdomains. The indicated peak is not displayed at basic shift of pH. The interaction with propranolol, clonidine, phenylephrine, carbachol and tripeptide fMLP which hinder adenylate cyclase (AdC) and activate Ca-polyphosphoinositide (Ca-PPI) signaling system of a cell initiates structural rearrangements similar to acidic transitions. Isoproterenol, yohimbine diphenhydramine, chlorpromazine and atropine, which activate AdC and hinder Ca-PPI, cause conformational changes of HSA similar to basic transitions.

Anatomy and physiology of genital organs - women.

PubMed

Graziottin, Alessandra; Gambini, Dania

2015-01-01

"Anatomy is destiny": Sigmund Freud viewed human anatomy as a necessary, although not a sufficient, condition for understanding the complexity of human sexual function with a solid biologic basis. The aim of the chapter is to describe women's genital anatomy and physiology, focusing on women's sexual function with a clinically oriented vision. Key points include: embryology, stressing that the "female" is the anatomic "default" program, differentiated into "male" only in the presence of androgens at physiologic levels for the gestational age; sex determination and sex differentiation, describing the interplay between anatomic and endocrine factors; the "clitoral-urethral-vaginal" complex, the most recent anatomy reading of the corpora cavernosa pattern in women; the controversial G spot; the role of the pelvic floor muscles in modulating vaginal receptivity and intercourse feelings, with hyperactivity leading to introital dyspareunia and contributing to provoked vestibulodynia and recurrent postcoital cystitis, whilst lesions during delivery reduce vaginal sensations, genital arousability, and orgasm; innervation, vessels, bones, ligaments; and the physiology of women's sexual response. Attention to physiologic aging focuses on "low-grade inflammation," genital and systemic, with its impact on women sexual function, especially after the menopause, if the woman does not or cannot use hormone replacement therapy. © 2015 Elsevier B.V. All rights reserved.

Involuntary Attention and Physiological Arousal Evoked by Structural Features and Emotional Content in TV Commercials.

ERIC Educational Resources Information Center

Lang, Annie

1990-01-01

Examines how emotional content in televised messages intensifies physiological attentional responses. Explains that heart rate data indicating both shorter-term responses and longer-term arousal were collected from 10 female and 4 male advertising students. Finds that emotional content increases physiological arousal in viewers and that heart…

Physiology is rocking the foundations of evolutionary biology.

PubMed

Noble, Denis

2013-08-01

The 'Modern Synthesis' (Neo-Darwinism) is a mid-20th century gene-centric view of evolution, based on random mutations accumulating to produce gradual change through natural selection. Any role of physiological function in influencing genetic inheritance was excluded. The organism became a mere carrier of the real objects of selection, its genes. We now know that genetic change is far from random and often not gradual. Molecular genetics and genome sequencing have deconstructed this unnecessarily restrictive view of evolution in a way that reintroduces physiological function and interactions with the environment as factors influencing the speed and nature of inherited change. Acquired characteristics can be inherited, and in a few but growing number of cases that inheritance has now been shown to be robust for many generations. The 21st century can look forward to a new synthesis that will reintegrate physiology with evolutionary biology.

The Role of Flipped Learning in Managing the Cognitive Load of a Threshold Concept in Physiology

ERIC Educational Resources Information Center

Akkaraju, Shylaja

2016-01-01

To help students master challenging, threshold concepts in physiology, I used the flipped learning model in a human anatomy and physiology course with very encouraging results in terms of student motivation, preparedness, engagement, and performance. The flipped learning model was enhanced by pre-training and formative assessments that provided…

[Regional differences in ikigai (reason(s) for living) in elderly people--relationship between ikigai and family structure, physiological situation and functional capacity].

PubMed

Hasegawa, Akihiro; Fujiwara, Yoshinori; Hoshi, Tanji; Shinkai, Shoji

2003-07-01

The purpose of this paper is a) to make a comparative study of the existence of ikigai (reason(s) for living) in elderly people and its relevance to their family structure, physiological situation and functional capacity in both rural areas and metropolitan suburban areas, and b) position basic research into the structure of ikigai in the near future, by clarifying several related factors, from which the concept of ikigai may be defined. The meaning of the word "ikigai" in Japanese is difficult to express exactly, and specialists in gerontology have varying definitions. If ikigai were translated from Japanese into English, it could be "reason(s) for living", "self-actualization", "meaning of life" and/or "purpose in life". In this paper, ikigai is used to mean "feeling of being alive now and/or individual motivation for living". As of October 2000, we studied 1,544 people aged 65 years and over living in town Y of Niigata Prefecture (rural area), and as of January 2001, we studied 1,002 people in the same age group in town H of Saitama Prefecture (metropolitan suburban area). The above investigations revealed the following characteristics:--(a) Regarding the percentages of persons having or not having ikigai, there were no significant differences between the rural area and the metropolitan suburban area. (b) In both areas, the 3 factors of self-rated level of health, intellectual activeness and social roles, were associated with having ikigai. (c) In the rural area, the family structure was strongly associated with having ikigai, but gender or generation were irrelevant. (d) In the metropolitan suburban area, the hospitalization experience of men was strongly associated with ikigai. Furthermore, there was a strong correlation with generation. In this regard, while the contents of ikigai are seldom examined in detail, clarification of the structure of ikigai should be worked out in the next stage of the study, using covariance structure analysis. In addition the

Lithium: a versatile tool for understanding renal physiology

PubMed Central

Ecelbarger, Carolyn M.

2013-01-01

By virtue of its unique interactions with kidney cells, lithium became an important research tool in renal physiology and pathophysiology. Investigators have uncovered the intricate relationships of lithium with the vasopressin and aldosterone systems, and the membrane channels or transporters regulated by them. While doing so, their work has also led to 1) questioning the role of adenylyl cyclase activity and prostaglandins in lithium-induced suppression of aquaporin-2 gene transcription; 2) unraveling the role of purinergic signaling in lithium-induced polyuria; and 3) highlighting the importance of the epithelial sodium channel (ENaC) in lithium-induced nephrogenic diabetes insipidus (NDI). Lithium-induced remodeling of the collecting duct has the potential to shed new light on collecting duct remodeling in disease conditions, such as diabetes insipidus. The finding that lithium inhibits glycogen synthase kinase-3β (GSK3β) has opened an avenue for studies on the role of GSK3β in urinary concentration, and GSK isoforms in renal development. Finally, proteomic and metabolomic profiling of the kidney and urine in rats treated with lithium is providing insights into how the kidney adapts its metabolism in conditions such as acquired NDI and the multifactorial nature of lithium-induced NDI. This review provides state-of-the-art knowledge of lithium as a versatile tool for understanding the molecular physiology of the kidney, and a comprehensive view of how this tool is challenging some of our long-standing concepts in renal physiology, often with paradigm shifts, and presenting paradoxical situations in renal pathophysiology. In addition, this review points to future directions in research where lithium can lead the renal community. PMID:23408166

The Emergence of Physiology and Form: Natural Selection Revisited

PubMed Central

Torday, John S.

2016-01-01

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

Effects of simulated microgravity on Streptococcus mutans physiology and biofilm structure.

PubMed

Cheng, Xingqun; Xu, Xin; Chen, Jing; Zhou, Xuedong; Cheng, Lei; Li, Mingyun; Li, Jiyao; Wang, Renke; Jia, Wenxiang; Li, Yu-Qing

2014-10-01

Long-term spaceflights will eventually become an inevitable occurrence. Previous studies have indicated that oral infectious diseases, including dental caries, were more prevalent in astronauts due to the effect of microgravity. However, the impact of the space environment, especially the microgravity environment, on the virulence factors of Streptococcus mutans, a major caries-associated bacterium, is yet to be explored. In the present study, we investigated the impact of simulated microgravity on the physiology and biofilm structure of S. mutans. We also explored the dual-species interaction between S. mutans and Streptococcus sanguinis under a simulated microgravity condition. Results indicated that the simulated microgravity condition can enhance the acid tolerance ability, modify the biofilm architecture and extracellular polysaccharide distribution of S. mutans, and increase the proportion of S. mutans within a dual-species biofilm, probably through the regulation of various gene expressions. We hypothesize that the enhanced competitiveness of S. mutans under simulated microgravity may cause a multispecies micro-ecological imbalance, which would result in the initiation of dental caries. Our current findings are consistent with previous studies, which revealed a higher astronaut-associated incidence of caries. Further research is required to explore the detailed mechanisms. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Defensive Physiological Reactions to Rejection

PubMed Central

Gyurak, Anett; Ayduk, Özlem

2014-01-01

We examined the hypothesis that rejection automatically elicits defensive physiological reactions in people with low self-esteem (SE) but that attentional control moderates this effect. Undergraduates (N = 67) completed questionnaire measures of SE and attentional control. Their eye-blink responses to startle probes were measured while they viewed paintings related to rejection and acceptance themes. The stimuli also included positive-, negative-, and neutral-valence control paintings unrelated to rejection. As predicted, compared with people high in SE, those low in SE showed stronger startle eye-blink responses to paintings related to rejection, but not to negative paintings. Paintings related to acceptance did not attenuate their physiological reactivity. Furthermore, attentional control moderated their sensitivity to rejection, such that low SE was related to greater eye-blink responses to rejection only among individuals who were low in attentional control. Implications of the role of attentional control as a top-down process regulating emotional reactivity in people with low SE are discussed. PMID:17894606

Homeostatic reinforcement learning for integrating reward collection and physiological stability.

PubMed

Keramati, Mehdi; Gutkin, Boris

2014-12-02

Efficient regulation of internal homeostasis and defending it against perturbations requires adaptive behavioral strategies. However, the computational principles mediating the interaction between homeostatic and associative learning processes remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behaviors may be modulated by internal states. Within this framework, we mathematically prove that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further suggest a formal basis for temporal discounting of rewards by showing that discounting motivates animals to follow the shortest path in the space of physiological variables toward the desired setpoint. We also explain how animals learn to act predictively to preclude prospective homeostatic challenges, and several other behavioral patterns. Finally, we suggest a computational role for interaction between hypothalamus and the brain reward system.

A brief history of bacterial growth physiology.

PubMed

Schaechter, Moselio

2015-01-01

Arguably, microbial physiology started when Leeuwenhoek became fascinated by observing a Vorticella beating its cilia, my point being that almost any observation of microbes has a physiological component. With the advent of modern microbiology in the mid-19th century, the field became recognizably distinctive with such discoveries as anaerobiosis, fermentation as a biological phenomenon, and the nutritional requirements of microbes. Soon came the discoveries of Winogradsky and his followers of the chemical changes in the environment that result from microbial activities. Later, during the first half of the 20th century, microbial physiology became the basis for much of the elucidation of central metabolism. Bacterial physiology then became a handmaiden of molecular biology and was greatly influenced by the discovery of cellular regulatory mechanisms. Microbial growth, which had come of age with the early work of Hershey, Monod, and others, was later pursued by studies on a whole cell level by what became known as the "Copenhagen School." During this time, the exploration of physiological activities became coupled to modern inquiries into the structure of the bacterial cell. Recent years have seen the development of a further phase in microbial physiology, one seeking a deeper quantitative understanding of phenomena on a whole cell level. This pursuit is exemplified by the emergence of systems biology, which is made possible by the development of technologies that permit the gathering of information in huge amounts. As has been true through history, the research into microbial physiology continues to be guided by the development of new methods of analysis. Some of these developments may well afford the possibility of making stunning breakthroughs.

Biochemistry and physiology of hexose-6-phosphate knockout mice.

PubMed

Zielinska, Agnieszka E; Walker, Elizabeth A; Stewart, Paul M; Lavery, Gareth G

2011-04-10

Hexose-6-phosphate dehydrogenase (H6PDH) has emerged as an important factor in setting the redox status of the endoplasmic reticulum (ER) lumen. An important role of H6PDH is to generate a high NADPH/NADP(+) ratio which permits 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) to act as an oxo-reductase, catalyzing the activation of glucocorticoids (GCs). In H6PDH knockout mice 11β-HSD1 assumes dehydrogenase activity and inactivates GCs, rendering the target cell relatively GC insensitive. Consequently, H6PDHKO mice have a phenotype consistent with defects in the permissive and adaptive actions of GCs upon physiology. H6PDHKO mice have also offered an insight into muscle physiology as they also present with a severe vacuolating myopathy, abnormalities of glucose homeostasis and activation of the unfolded protein response due to ER stress, and a number of mechanisms driving this phenotype are thought to be involved. This article will review what we understand of the redox control of GC hormone metabolism regulated by H6PDH, and how H6PDHKO mice have allowed an in-depth understanding of its potentially novel, GC-independent roles in muscle physiology. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Role of renal sensory nerves in physiological and pathophysiological conditions

PubMed Central

2014-01-01

Whether activation of afferent renal nerves contributes to the regulation of arterial pressure and sodium balance has been long overlooked. In normotensive rats, activating renal mechanosensory nerves decrease efferent renal sympathetic nerve activity (ERSNA) and increase urinary sodium excretion, an inhibitory renorenal reflex. There is an interaction between efferent and afferent renal nerves, whereby increases in ERSNA increase afferent renal nerve activity (ARNA), leading to decreases in ERSNA by activation of the renorenal reflexes to maintain low ERSNA to minimize sodium retention. High-sodium diet enhances the responsiveness of the renal sensory nerves, while low dietary sodium reduces the responsiveness of the renal sensory nerves, thus producing physiologically appropriate responses to maintain sodium balance. Increased renal ANG II reduces the responsiveness of the renal sensory nerves in physiological and pathophysiological conditions, including hypertension, congestive heart failure, and ischemia-induced acute renal failure. Impairment of inhibitory renorenal reflexes in these pathological states would contribute to the hypertension and sodium retention. When the inhibitory renorenal reflexes are suppressed, excitatory reflexes may prevail. Renal denervation reduces arterial pressure in experimental hypertension and in treatment-resistant hypertensive patients. The fall in arterial pressure is associated with a fall in muscle sympathetic nerve activity, suggesting that increased ARNA contributes to increased arterial pressure in these patients. Although removal of both renal sympathetic and afferent renal sensory nerves most likely contributes to the arterial pressure reduction initially, additional mechanisms may be involved in long-term arterial pressure reduction since sympathetic and sensory nerves reinnervate renal tissue in a similar time-dependent fashion following renal denervation. PMID:25411364

Mechanisms of physiological and pathological cardiac hypertrophy.

PubMed

Nakamura, Michinari; Sadoshima, Junichi

2018-04-19

Cardiomyocytes exit the cell cycle and become terminally differentiated soon after birth. Therefore, in the adult heart, instead of an increase in cardiomyocyte number, individual cardiomyocytes increase in size, and the heart develops hypertrophy to reduce ventricular wall stress and maintain function and efficiency in response to an increased workload. There are two types of hypertrophy: physiological and pathological. Hypertrophy initially develops as an adaptive response to physiological and pathological stimuli, but pathological hypertrophy generally progresses to heart failure. Each form of hypertrophy is regulated by distinct cellular signalling pathways. In the past decade, a growing number of studies have suggested that previously unrecognized mechanisms, including cellular metabolism, proliferation, non-coding RNAs, immune responses, translational regulation, and epigenetic modifications, positively or negatively regulate cardiac hypertrophy. In this Review, we summarize the underlying molecular mechanisms of physiological and pathological hypertrophy, with a particular emphasis on the role of metabolic remodelling in both forms of cardiac hypertrophy, and we discuss how the current knowledge on cardiac hypertrophy can be applied to develop novel therapeutic strategies to prevent or reverse pathological hypertrophy.

Spatial Distribution, Structure, Biomass, and Physiology of Microbial Assemblages across the Southern Ocean Frontal Zones during the Late Austral Winter

PubMed Central

Hanson, Roger B.; Lowery, H. Kenneth

1985-01-01

We examined the spatial distributions of picoplankton, nanoplankton, and microplankton biomass and physiological state relative to the hydrography of the Southern Ocean along 90° W longitude and across the Drake Passage in the late austral winter. The eastern South Pacific Ocean showed some large-scale biogeographical differences and size class variability. Microbial ATP biomass was greatest in euphotic surface waters. The horizontal distributions of microbial biomass and physiological state (adenylate energy charge ratio) coincided with internal currents (fronts) of the Antarctic Circumpolar Current. In the Drake Passage, the biological scales in the euphotic and aphotic zones were complex, and ATP, total adenylate, and adenylate energy charge ratio isopleths were compressed due to the extension of the sea ice from Antarctica and constriction of the Circumpolar Current through the narrow passage. The physiological state of microbial assemblages and biomass were much higher in the Drake Passage than in the eastern South Pacific Ocean. The temperature of Antarctic waters, not dissolved organic carbon, was the major variable controlling picoplankton growth. Estimates of picoplankton production based on ATP increments with time suggest that production under reduced predation pressure was 1 to 10 μg of carbon per liter per day. Our results demonstrate the influence of large-scale hydrographic processes on the distribution and structure of microplankton, nanoplankton, and picoplankton across the Southern Ocean. PMID:16346777

The Role of Structural Characteristics in Problematic Video Game Play: An Empirical Study

ERIC Educational Resources Information Center

King, Daniel L.; Delfabbro, Paul H.; Griffiths, Mark D.

2011-01-01

The research literature suggests that the structural characteristics of video games may play a considerable role in the initiation, development and maintenance of problematic video game playing. The present study investigated the role of structural characteristics in video game playing behaviour within a sample of 421 video game players aged…

Physiological mechanisms underlying animal social behaviour.

PubMed

Seebacher, Frank; Krause, Jens

2017-08-19

Many species of animal live in groups, and the group represents the organizational level within which ecological and evolutionary processes occur. Understanding these processes, therefore, relies on knowledge of the mechanisms that permit or constrain group formation. We suggest that physiological capacities and differences in physiology between individuals modify fission-fusion dynamics. Differences between individuals in locomotor capacity and metabolism may lead to fission of groups and sorting of individuals into groups with similar physiological phenotypes. Environmental impacts such as hypoxia can influence maximum group sizes and structure in fish schools by altering access to oxygenated water. The nutritional environment determines group cohesion, and the increase in information collected by the group means that individuals should rely more on social information and form more cohesive groups in uncertain environments. Changing environmental contexts require rapid responses by individuals to maintain group coordination, which are mediated by neuroendocrine signalling systems such as nonapeptides and steroid hormones. Brain processing capacity may constrain social complexity by limiting information processing. Failure to evaluate socially relevant information correctly limits social interactions, which is seen, for example, in autism. Hence, functioning of a group relies to a large extent on the perception and appropriate processing of signals from conspecifics. Many if not all physiological systems are mechanistically linked, and therefore have synergistic effects on social behaviour. A challenge for the future lies in understanding these interactive effects, which will improve understanding of group dynamics, particularly in changing environments.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'. © 2017 The Author(s).

Physiological mechanisms underlying animal social behaviour

PubMed Central

2017-01-01

Many species of animal live in groups, and the group represents the organizational level within which ecological and evolutionary processes occur. Understanding these processes, therefore, relies on knowledge of the mechanisms that permit or constrain group formation. We suggest that physiological capacities and differences in physiology between individuals modify fission–fusion dynamics. Differences between individuals in locomotor capacity and metabolism may lead to fission of groups and sorting of individuals into groups with similar physiological phenotypes. Environmental impacts such as hypoxia can influence maximum group sizes and structure in fish schools by altering access to oxygenated water. The nutritional environment determines group cohesion, and the increase in information collected by the group means that individuals should rely more on social information and form more cohesive groups in uncertain environments. Changing environmental contexts require rapid responses by individuals to maintain group coordination, which are mediated by neuroendocrine signalling systems such as nonapeptides and steroid hormones. Brain processing capacity may constrain social complexity by limiting information processing. Failure to evaluate socially relevant information correctly limits social interactions, which is seen, for example, in autism. Hence, functioning of a group relies to a large extent on the perception and appropriate processing of signals from conspecifics. Many if not all physiological systems are mechanistically linked, and therefore have synergistic effects on social behaviour. A challenge for the future lies in understanding these interactive effects, which will improve understanding of group dynamics, particularly in changing environments. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’. PMID:28673909

Listening to music and physiological and psychological functioning: the mediating role of emotion regulation and stress reactivity.

PubMed

Thoma, M V; Scholz, U; Ehlert, U; Nater, U M

2012-01-01

Music listening has been suggested to have short-term beneficial effects. The aim of this study was to investigate the association and potential mediating mechanisms between various aspects of habitual music-listening behaviour and physiological and psychological functioning. An internet-based survey was conducted in university students, measuring habitual music-listening behaviour, emotion regulation, stress reactivity, as well as physiological and psychological functioning. A total of 1230 individuals (mean = 24.89 ± 5.34 years, 55.3% women) completed the questionnaire. Quantitative aspects of habitual music-listening behaviour, i.e. average duration of music listening and subjective relevance of music, were not associated with physiological and psychological functioning. In contrast, qualitative aspects, i.e. reasons for listening (especially 'reducing loneliness and aggression', and 'arousing or intensifying specific emotions') were significantly related to physiological and psychological functioning (all p = 0.001). These direct effects were mediated by distress-augmenting emotion regulation and individual stress reactivity. The habitual music-listening behaviour appears to be a multifaceted behaviour that is further influenced by dispositions that are usually not related to music listening. Consequently, habitual music-listening behaviour is not obviously linked to physiological and psychological functioning.

The role of non-rainfall water on physiological activation in desert biological soil crusts

NASA Astrophysics Data System (ADS)

Zheng, Jiaoli; Peng, Chengrong; Li, Hua; Li, Shuangshuang; Huang, Shun; Hu, Yao; Zhang, Jinli; Li, Dunhai

2018-01-01

Non-rainfall water (NRW, e.g. fog and dew), in addition to rainfall and snowfall, are considered important water inputs to drylands. At the same time, biological soil crusts (BSCs) are important components of drylands. However, little information is available regarding the effect of NRW inputs on BSC activation. In this study, the effects of NRW on physiological activation in three BSC successional stages, including the cyanobacteria crust stage (Crust-C), moss colonization stage (Crust-CM), and moss crust stage (Crust-M), were studied in situ. Results suggest NRW inputs hydrated and activated physiological activity (Fv/Fm, carbon exchange, and nitrogen fixation) in BSCs but led to a negative carbon balance and low rates of nitrogen fixation in BSCs. One effective NRW event could hydrate BSCs for 7 h. Following simulated rainfall, the physiological activities recovered within 3 h, and net carbon gain occurred until 3 h after hydration, whereas NRW-induced physiological recovery processes were slower and exhibited lower activities, leading to a negative carbon balance. There were significant positive correlations between NRW amounts and the recovered values of Fv/Fm in all the three BSC stages (p < .001). The thresholds for Fv/Fm activation decreased with BSC succession, and the annual effective NRW events increased with BSC succession, with values of 29.8, 89.2, and 110.7 in Crust-C, Crust-CM and Crust-M, respectively. The results suggest that moss crust and moss-cyanobacteria crust use NRW to prolong metabolic activity and reduce drought stress more efficiently than cyanobacteria crusts. Therefore, these results suggest that BSCs utilize NRW to sustain life while growth and biomass accumulation require precipitation (rainfall) events over a certain threshold.

An Essential Physiological Role for MCT8 in Bone in Male Mice

PubMed Central

Leitch, Victoria D.; Di Cosmo, Caterina; Liao, Xiao-Hui; O’Boy, Sam; Galliford, Thomas M.; Evans, Holly; Croucher, Peter I.; Boyde, Alan; Dumitrescu, Alexandra; Weiss, Roy E.; Refetoff, Samuel; Williams, Graham R.

2017-01-01

T3 is an important regulator of skeletal development and adult bone maintenance. Thyroid hormone action requires efficient transport of T4 and T3 into target cells. We hypothesized that monocarboxylate transporter (MCT) 8, encoded by Mct8 on the X-chromosome, is an essential thyroid hormone transporter in bone. To test this hypothesis, we determined the juvenile and adult skeletal phenotypes of male Mct8 knockout mice (Mct8KO) and Mct8D1D2KO compound mutants, which additionally lack the ability to convert the prohormone T4 to the active hormone T3. Prenatal skeletal development was normal in both Mct8KO and Mct8D1D2KO mice, whereas postnatal endochondral ossification and linear growth were delayed in both Mct8KO and Mct8D1D2KO mice. Furthermore, bone mass and mineralization were decreased in adult Mct8KO and Mct8D1D2KO mice, and compound mutants also had reduced bone strength. Delayed bone development and maturation in Mct8KO and Mct8D1D2KO mice is consistent with decreased thyroid hormone action in growth plate chondrocytes despite elevated serum T3 concentrations, whereas low bone mass and osteoporosis reflects increased thyroid hormone action in adult bone due to elevated systemic T3 levels. These studies identify an essential physiological requirement for MCT8 in chondrocytes, and demonstrate a role for additional transporters in other skeletal cells during adult bone maintenance. PMID:28637283

The Biological Role of Nestin(+)-Cells in Physiological and Pathological Cardiovascular Remodeling

PubMed Central

Calderone, Angelino

2018-01-01

The intermediate filament protein nestin was identified in diverse populations of cells implicated in cardiovascular remodeling. Cardiac resident neural progenitor/stem cells constitutively express nestin and following an ischemic insult migrate to the infarct region and participate in angiogenesis and neurogenesis. A modest number of normal adult ventricular fibroblasts express nestin and the intermediate filament protein is upregulated during the progression of reparative and reactive fibrosis. Nestin depletion attenuates cell cycle re-entry suggesting that increased expression of the intermediate filament protein in ventricular fibroblasts may represent an activated phenotype accelerating the biological impact during fibrosis. Nestin immunoreactivity is absent in normal adult rodent ventricular cardiomyocytes. Following ischemic damage, the intermediate filament protein is induced in a modest population of pre-existing adult ventricular cardiomyocytes bordering the peri-infarct/infarct region and nestin(+)-ventricular cardiomyocytes were identified in the infarcted human heart. The appearance of nestin(+)-ventricular cardiomyocytes post-myocardial infarction (MI) recapitulates an embryonic phenotype and depletion of the intermediate filament protein inhibits cell cycle re-entry. Recruitment of the serine/threonine kinase p38 MAPK secondary to an overt inflammatory response after an ischemic insult may represent a seminal event limiting the appearance of nestin(+)-ventricular cardiomyocytes and concomitantly suppressing cell cycle re-entry. Endothelial and vascular smooth muscle cells (VSMCs) express nestin and upregulation of the intermediate filament protein may directly contribute to vascular remodeling. This review will highlight the biological role of nestin(+)-cells during physiological and pathological remodeling of the heart and vasculature and discuss the phenotypic advantage attributed to the intermediate filament protein. PMID:29492403

Biofield Physiology: A Framework for an Emerging Discipline

PubMed Central

Levin, Michael; McCraty, Rollin; Bat, Namuun; Ives, John A.; Lutgendorf, Susan K.; Oschman, James L.

2015-01-01

Biofield physiology is proposed as an overarching descriptor for the electromagnetic, biophotonic, and other types of spatially-distributed fields that living systems generate and respond to as integral aspects of cellular, tissue, and whole organism self-regulation and organization. Medical physiology, cell biology, and biophysics provide the framework within which evidence for biofields, their proposed receptors, and functions is presented. As such, biofields can be viewed as affecting physiological regulatory systems in a manner that complements the more familiar molecular-based mechanisms. Examples of clinically relevant biofields are the electrical and magnetic fields generated by arrays of heart cells and neurons that are detected, respectively, as electrocardiograms (ECGs) or magnetocardiograms (MCGs) and electroencephalograms (EEGs) or magnetoencephalograms (MEGs). At a basic physiology level, electromagnetic activity of neural assemblies appears to modulate neuronal synchronization and circadian rhythmicity. Numerous nonneural electrical fields have been detected and analyzed, including those arising from patterns of resting membrane potentials that guide development and regeneration, and from slowly-varying transepithelial direct current fields that initiate cellular responses to tissue damage. Another biofield phenomenon is the coherent, ultraweak photon emissions (UPE), detected from cell cultures and from the body surface. A physiological role for biophotons is consistent with observations that fluctuations in UPE correlate with cerebral blood flow, cerebral energy metabolism, and EEG activity. Biofield receptors are reviewed in 3 categories: molecular-level receptors, charge flux sites, and endogenously generated electric or electromagnetic fields. In summary, sufficient evidence has accrued to consider biofield physiology as a viable scientific discipline. Directions for future research are proposed. PMID:26665040

Biofield Physiology: A Framework for an Emerging Discipline.

PubMed

Hammerschlag, Richard; Levin, Michael; McCraty, Rollin; Bat, Namuun; Ives, John A; Lutgendorf, Susan K; Oschman, James L

2015-11-01

Biofield physiology is proposed as an overarching descriptor for the electromagnetic, biophotonic, and other types of spatially-distributed fields that living systems generate and respond to as integral aspects of cellular, tissue, and whole organism self-regulation and organization. Medical physiology, cell biology, and biophysics provide the framework within which evidence for biofields, their proposed receptors, and functions is presented. As such, biofields can be viewed as affecting physiological regulatory systems in a manner that complements the more familiar molecular-based mechanisms. Examples of clinically relevant biofields are the electrical and magnetic fields generated by arrays of heart cells and neurons that are detected, respectively, as electrocardiograms (ECGs) or magnetocardiograms (MCGs) and electroencephalograms (EEGs) or magnetoencephalograms (MEGs). At a basic physiology level, electromagnetic activity of neural assemblies appears to modulate neuronal synchronization and circadian rhythmicity. Numerous nonneural electrical fields have been detected and analyzed, including those arising from patterns of resting membrane potentials that guide development and regeneration, and from slowly-varying transepithelial direct current fields that initiate cellular responses to tissue damage. Another biofield phenomenon is the coherent, ultraweak photon emissions (UPE), detected from cell cultures and from the body surface. A physiological role for biophotons is consistent with observations that fluctuations in UPE correlate with cerebral blood flow, cerebral energy metabolism, and EEG activity. Biofield receptors are reviewed in 3 categories: molecular-level receptors, charge flux sites, and endogenously generated electric or electromagnetic fields. In summary, sufficient evidence has accrued to consider biofield physiology as a viable scientific discipline. Directions for future research are proposed.

[P4-ATP-ase Atp8b1/FIC1: structural properties and (patho)physiological functions].

PubMed

Korneenko, T V; Pestov, N B; Okkelman, I A; Modyanov, N N; Shakhparonov, M I

2015-01-01

P4-ATP-ases comprise an interesting family among P-type ATP-ases, since they are thought to play a major role in the transfer of phospholipids such as phosphatydylserine from the outer leaflet to the inner leaflet. Isoforms of P4-ATP-ases are partially interchangeable but peculiarities of tissue-specific expression of their genes, intracellular localization of proteins, as well as regulatory pathways lead to the fact that, on the organismal level, serious pathologies may develop in the presence of structural abnormalities in certain isoforms. Among P4-ATP-ases a special place is occupied by ATP8B1, for which several mutations are known that lead to serious hereditary diseases: two forms of congenital cholestasis (PFIC1 or Byler disease and benign recurrent intrahepatic cholestasis) with extraliver symptoms such as sensorineural hearing loss. The physiological function of the Atp8b1/FIC1 protein is known in general outline: it is responsible for transport of certain phospholipids (phosphatydylserine, cardiolipin) for the outer monolayer of the plasma membrane to the inner one. It is well known that perturbation of membrane asymmetry, caused by the lack of Atp8B1 activity, leads to death of hairy cells of the inner ear, dysfunction of bile acid transport in liver-cells that causes cirrhosis. It is also probable that insufficient activity of Atp8b1/FIC1 increases susceptibility to bacterial pneumonia.Regulatory pathways of Atp8b1/FIC1 activity in vivo remain to be insufficiently studied and this opens novel perspectives for research in this field that may allow better understanding of molecular processes behind the development of certain pathologies and to reveal novel therapeutical targets.

Homeostatic reinforcement learning for integrating reward collection and physiological stability

PubMed Central

Keramati, Mehdi; Gutkin, Boris

2014-01-01

Efficient regulation of internal homeostasis and defending it against perturbations requires adaptive behavioral strategies. However, the computational principles mediating the interaction between homeostatic and associative learning processes remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behaviors may be modulated by internal states. Within this framework, we mathematically prove that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further suggest a formal basis for temporal discounting of rewards by showing that discounting motivates animals to follow the shortest path in the space of physiological variables toward the desired setpoint. We also explain how animals learn to act predictively to preclude prospective homeostatic challenges, and several other behavioral patterns. Finally, we suggest a computational role for interaction between hypothalamus and the brain reward system. DOI: http://dx.doi.org/10.7554/eLife.04811.001 PMID:25457346

Regulation and physiological role of silicon in alleviating drought stress of mango.

PubMed

Helaly, Mohamed Naser; El-Hoseiny, Hanan; El-Sheery, Nabil Ibrahim; Rastogi, Anshu; Kalaji, Hazem M

2017-09-01

Improvement of drought stress of mango plants requires intensive research that focuses on physiological processes. In three successive seasons (2014, 2015and 2016) field experiments with four different strains of mango were subjected to two water regimes. The growth and physiological parameters of possible relevance for drought stress tolerances in mango were investigated. Yield and its components were also evaluated. The data showed that all growth and physiological parameters were increased under K 2 SiO 3 (Si) supplement and were followed by the interaction treatment (Si treatment and its combination with drought stress) compared to that of the controlled condition. Drought stress decreased the concentration of auxins (IAA), gibberellins (GA) and cytokinins (CK) in the three mango cultivars leaves, whereas, it increased the concentration of abscisic acid (ABA). On the contrary, IAA, GA, and CK (promoters) endogenous levels were improved by supplementing Si, in contrary ABA was decreased. Drought stress increased the activity of peroxidase (POX), catalase (CAT), and superoxide dismutase (SOD) in the leaves of all mango cultivars grown during three experimental seasons. However, Si supplementation reduced the levels of all these antioxidative enzymes, especially the concentration of SOD when compared to that of control leaves. Fruit quality was improved in three successive seasons when Si was applied. Our results clearly show that the increment in drought tolerance was associated with an increase in antioxidative enzyme activity, allowing mango plants to cope better with drought stress. Si possesses an efficient system for scavenging reactive oxygen species, which protects the plant against destructive oxidative reactions, thereby improving the ability of the mango trees to withstand environmental stress in arid regions. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Gut Melatonin in Vertebrates: Chronobiology and Physiology.

PubMed

Mukherjee, Sourav; Maitra, Saumen Kumar

2015-01-01

Melatonin, following discovery in the bovine pineal gland, has been detected in several extra-pineal sources including gastrointestinal tract or gut. Arylalkylamine N-acetyltransferase (AANAT) is the key regulator of its biosynthesis. Melatonin in pineal is rhythmically produced with a nocturnal peak in synchronization with environmental light-dark cycle. A recent study on carp reported first that melatonin levels and intensity of a ~23 kDa AANAT protein in each gut segment also exhibit significant daily variations but, unlike pineal, show a peak at midday in all seasons. Extensive experimental studies ruled out direct role of light-dark conditions in determining temporal pattern of gut melatoninergic system in carp, and opened up possible role of environmental non-photic cue(s) as its synchronizer. Based on mammalian findings, physiological significance of gut-derived melatonin also appears unique because its actions at local levels sharing paracrine and/or autocrine functions have been emphasized. The purpose of this mini review is to summarize the existing data on the chronobiology and physiology of gut melatonin and to emphasize their relation with the same hormone derived in the pineal in vertebrates including fish.

Autonomic Physiological Response Patterns Related to Intelligence

ERIC Educational Resources Information Center

Melis, Cor; van Boxtel, Anton

2007-01-01

We examined autonomic physiological responses induced by six different cognitive ability tasks, varying in complexity, that were selected on the basis of on Guilford's Structure of Intellect model. In a group of 52 participants, task performance was measured together with nine different autonomic response measures and respiration rate. Weighted…

Determinants of physiological and perceived physiological stress reactivity in children and adolescents.

PubMed

Evans, Brittany E; Greaves-Lord, Kirstin; Euser, Anja S; Tulen, Joke H M; Franken, Ingmar H A; Huizink, Anja C

2013-01-01

Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity. In a stratified sample of 363 children (7-12 years) and 344 adolescents (13-20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure. Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant. As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness.

Physiology and emerging biochemistry of the glucagon-like peptide-1 receptor.

PubMed

Willard, Francis S; Sloop, Kyle W

2012-01-01

The glucagon-like peptide-1 (GLP-1) receptor is one of the best validated therapeutic targets for the treatment of type 2 diabetes mellitus (T2DM). Over several years, the accumulation of basic, translational, and clinical research helped define the physiologic roles of GLP-1 and its receptor in regulating glucose homeostasis and energy metabolism. These efforts provided much of the foundation for pharmaceutical development of the GLP-1 receptor peptide agonists, exenatide and liraglutide, as novel medicines for patients suffering from T2DM. Now, much attention is focused on better understanding the molecular mechanisms involved in ligand induced signaling of the GLP-1 receptor. For example, advancements in biophysical and structural biology techniques are being applied in attempts to more precisely determine ligand binding and receptor occupancy characteristics at the atomic level. These efforts should better inform three-dimensional modeling of the GLP-1 receptor that will help inspire more rational approaches to identify and optimize small molecule agonists or allosteric modulators targeting the GLP-1 receptor. This article reviews GLP-1 receptor physiology with an emphasis on GLP-1 induced signaling mechanisms in order to highlight new molecular strategies that help determine desired pharmacologic characteristics for guiding development of future nonpeptide GLP-1 receptor activators.

Physiology and Emerging Biochemistry of the Glucagon-Like Peptide-1 Receptor

PubMed Central

Willard, Francis S.; Sloop, Kyle W.

2012-01-01

The glucagon-like peptide-1 (GLP-1) receptor is one of the best validated therapeutic targets for the treatment of type 2 diabetes mellitus (T2DM). Over several years, the accumulation of basic, translational, and clinical research helped define the physiologic roles of GLP-1 and its receptor in regulating glucose homeostasis and energy metabolism. These efforts provided much of the foundation for pharmaceutical development of the GLP-1 receptor peptide agonists, exenatide and liraglutide, as novel medicines for patients suffering from T2DM. Now, much attention is focused on better understanding the molecular mechanisms involved in ligand induced signaling of the GLP-1 receptor. For example, advancements in biophysical and structural biology techniques are being applied in attempts to more precisely determine ligand binding and receptor occupancy characteristics at the atomic level. These efforts should better inform three-dimensional modeling of the GLP-1 receptor that will help inspire more rational approaches to identify and optimize small molecule agonists or allosteric modulators targeting the GLP-1 receptor. This article reviews GLP-1 receptor physiology with an emphasis on GLP-1 induced signaling mechanisms in order to highlight new molecular strategies that help determine desired pharmacologic characteristics for guiding development of future nonpeptide GLP-1 receptor activators. PMID:22666230

Anthropometric and physiological characteristics of rugby union football players.

PubMed

Nicholas, C W

1997-06-01

Rugby union enjoys worldwide popularity, but there is a lack of comprehensive research into the anthropometric and physiological characteristics of its players and the demands of the game, particularly at the elite level. One of the possible explanations for this is that the sport has previously been primarily concerned with the aspects of skill related to the game, rather than the physical and physiological requirements. However, with the increased physiological demands being placed on the elite players (using the British Isles as an example), with the recent introduction of professionalism, regional championships, the World Cup and major tours, information about the demands of the game and the assessment of, and methods of improving, the anthropometric and physiological characteristics of its players, are of paramount importance. Match analysis has indicated that rugby is an interval or intermittent sport and players must be able to perform a large number of intensive efforts of 5 to 15 seconds' duration with less than 40 seconds' recovery between each bout of high intensity activity. These observations, together with the metabolic responses during the game, give some insight into its physiological demands and are a prerequisite in the development and prescription of training programmes by coaches in preparing individual players for competition. The results from studies reporting the anthropometric and physiological characteristics of rugby union players observed that these individuals had unique anthropometric and physiological attributes which depended on positional role and the playing standard. These have important implications for team selection and highlight the necessity for individualised training programmes and fitness attainment targets.

Genetic and pharmacological analysis identifies a physiological role for the AHR in epidermal differentiation

PubMed Central

van den Bogaard, Ellen; Podolsky, Michael; Smits, Jos; Cui, Xiao; John, Christian; Gowda, Krishne; Desai, Dhimant; Amin, Shantu; Schalkwijk, Joost; Perdew, Gary H.

2015-01-01

Stimulation of the aryl hydrocarbon receptor (AHR) by xenobiotics is known to affect epidermal differentiation and skin barrier formation. The physiological role of endogenous AHR signaling in keratinocyte differentiation is not known. We used murine and human skin models to address the hypothesis that AHR activation is required for normal keratinocyte differentiation. Using transcriptome analysis of Ahr-/- and Ahr+/+ murine keratinocytes, we found significant enrichment of differentially expressed genes linked to epidermal differentiation. Primary Ahr-/- keratinocytes showed a significant reduction in terminal differentiation gene and protein expression, similar to Ahr+/+ keratinocytes treated with AHR antagonists GNF351 and CH223191, or the selective AHR modulator (SAhRM), SGA360. In vitro keratinocyte differentiation led to increased AHR levels and subsequent nuclear translocation, followed by induced CYP1A1 gene expression. Monolayer cultured primary human keratinocytes treated with AHR antagonists also showed an impaired terminal differentiation program. Inactivation of AHR activity during human skin equivalent development severely impaired epidermal stratification, terminal differentiation protein expression and stratum corneum formation. As disturbed epidermal differentiation is a main feature of many skin diseases, pharmacological agents targeting AHR signaling or future identification of endogenous keratinocyte-derived AHR ligands should be considered as potential new drugs in dermatology. PMID:25602157

Fruit Calcium: Transport and Physiology

PubMed Central

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

2016-01-01

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

Physiological relaxation induced by horticultural activity: transplanting work using flowering plants.

PubMed

Lee, Min-sun; Park, Bum-jin; Lee, Juyoung; Park, Kun-tae; Ku, Ja-hyeong; Lee, Jun-woo; Oh, Kyung-ok; Miyazaki, Yoshifumi

2013-10-10

Despite increasing attention and a growing volume of research data, little physiological evidence is available on the benefits of horticultural activity and the different effects on individuals. Therefore, the aim of the present study was to investigate the physiological effects of horticultural activity and to examine how differences in personality alter these effects. The effects of transplanting real flowers (horticultural activity) and handling artificial flowers (control activity) on human physiological activity were compared. On the first day, eight participants engaged in horticultural activity and another eight in the control activity. On the second day, participants switched roles. Participants' physiological conditions during each activity were assessed by measuring the heart rate and heart rate variability (HRV). Psychological responses, which were measured using a semantic differential rating scale, showed that the horticultural activity promoted comfortable, soothed, and natural feelings, compared to the control activity. Analysis of physiological responses using two-way repeated measures analysis of variance (ANOVA) revealed that sympathetic nervous activity significantly decreased in the late time period (11 to 15 minutes) of horticultural activity only in the type A group. This study supports the fact that the horticultural activity can enhance psychological and physiological relaxation effects, although these physiological effects can differ among individuals with different personalities.

Physiological relaxation induced by horticultural activity: transplanting work using flowering plants

PubMed Central

2013-01-01

Background Despite increasing attention and a growing volume of research data, little physiological evidence is available on the benefits of horticultural activity and the different effects on individuals. Therefore, the aim of the present study was to investigate the physiological effects of horticultural activity and to examine how differences in personality alter these effects. Results The effects of transplanting real flowers (horticultural activity) and handling artificial flowers (control activity) on human physiological activity were compared. On the first day, eight participants engaged in horticultural activity and another eight in the control activity. On the second day, participants switched roles. Participants’ physiological conditions during each activity were assessed by measuring the heart rate and heart rate variability (HRV). Psychological responses, which were measured using a semantic differential rating scale, showed that the horticultural activity promoted comfortable, soothed, and natural feelings, compared to the control activity. Analysis of physiological responses using two-way repeated measures analysis of variance (ANOVA) revealed that sympathetic nervous activity significantly decreased in the late time period (11 to 15 minutes) of horticultural activity only in the type A group. Conclusions This study supports the fact that the horticultural activity can enhance psychological and physiological relaxation effects, although these physiological effects can differ among individuals with different personalities. PMID:24112302

Humor theories and the physiological benefits of laughter.

PubMed

Wilkins, Julia; Eisenbraun, Amy Janel

2009-01-01

There are 3 main theories used to explain the functions of humor: (1) the relief theory, (2) the incongruity theory, and (3) the superiority theory. While these theories focus on the specific role that humor plays for people in situations such as dealing with misfortune, making sense of rule violations, and bonding with others, we propose that underlying each of these theories are the physiological benefits of laughter. We draw on findings from empirical studies on laughter to demonstrate that these physiological benefits occur regardless of the theory that is used to explain the humor function. Findings from these studies have important implications for nurse practitioners working in hospice settings, long-term care facilities, nursing homes, and hospitals.

Role of LRRK2 in the regulation of dopamine receptor trafficking

PubMed Central

Sanna, Simona; Taymans, Jean Marc; Morari, Michele; Brugnoli, Alberto; Frassineti, Martina; Masala, Alessandra; Esposito, Sonia; Galioto, Manuela; Valle, Cristiana; Carri, Maria Teresa; Biosa, Alice; Greggio, Elisa; Crosio, Claudia

2017-01-01

Mutations in LRRK2 play a critical role in both familial and sporadic Parkinson’s disease (PD). Up to date, the role of LRRK2 in PD onset and progression remains largely unknown. However, experimental evidence highlights a critical role of LRRK2 in the control of vesicle trafficking that in turn may regulate different aspects of neuronal physiology. We have analyzed the role of LRRK2 in regulating dopamine receptor D1 (DRD1) and D2 (DRD2) trafficking. DRD1 and DRD2 are the most abundant dopamine receptors in the brain. They differ in structural, pharmacological and biochemical properties, as well as in localization and internalization mechanisms. Our results indicate that disease-associated mutant G2019S LRRK2 impairs DRD1 internalization, leading to an alteration in signal transduction. Moreover, the mutant forms of LRRK2 affect receptor turnover by decreasing the rate of DRD2 trafficking from the Golgi complex to the cell membrane. Collectively, our findings are consistent with the conclusion that LRRK2 influences the motility of neuronal vesicles and the neuronal receptor trafficking. These findings have important implications for the complex role that LRRK2 plays in neuronal physiology and the possible pathological mechanisms that may lead to neuronal death in PD. PMID:28582422

Regulation, Signaling, and Physiological Functions of G-Proteins.

PubMed

Syrovatkina, Viktoriya; Alegre, Kamela O; Dey, Raja; Huang, Xin-Yun

2016-09-25

Heterotrimeric guanine-nucleotide-binding regulatory proteins (G-proteins) mainly relay the information from G-protein-coupled receptors (GPCRs) on the plasma membrane to the inside of cells to regulate various biochemical functions. Depending on the targeted cell types, tissues, and organs, these signals modulate diverse physiological functions. The basic schemes of heterotrimeric G-proteins have been outlined. In this review, we briefly summarize what is known about the regulation, signaling, and physiological functions of G-proteins. We then focus on a few less explored areas such as the regulation of G-proteins by non-GPCRs and the physiological functions of G-proteins that cannot be easily explained by the known G-protein signaling pathways. There are new signaling pathways and physiological functions for G-proteins to be discovered and further interrogated. With the advancements in structural and computational biological techniques, we are closer to having a better understanding of how G-proteins are regulated and of the specificity of G-protein interactions with their regulators. Copyright © 2016 Elsevier Ltd. All rights reserved.

Linking vegetation structure, function and physiology through spectroscopic remote sensing

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Dissipative structures and biological rhythms

NASA Astrophysics Data System (ADS)

Goldbeter, Albert

2017-10-01

Sustained oscillations abound in biological systems. They occur at all levels of biological organization over a wide range of periods, from a fraction of a second to years, and with a variety of underlying mechanisms. They control major physiological functions, and their dysfunction is associated with a variety of physiological disorders. The goal of this review is (i) to give an overview of the main rhythms observed at the cellular and supracellular levels, (ii) to briefly describe how the study of biological rhythms unfolded in the course of time, in parallel with studies on chemical oscillations, (iii) to present the major roles of biological rhythms in the control of physiological functions, and (iv) the pathologies associated with the alteration, disappearance, or spurious occurrence of biological rhythms. Two tables present the main examples of cellular and supracellular rhythms ordered according to their period, and their role in physiology and pathophysiology. Among the rhythms discussed are neural and cardiac rhythms, metabolic oscillations such as those occurring in glycolysis in yeast, intracellular Ca++ oscillations, cyclic AMP oscillations in Dictyostelium amoebae, the segmentation clock that controls somitogenesis, pulsatile hormone secretion, circadian rhythms which occur in all eukaryotes and some bacteria with a period close to 24 h, the oscillatory dynamics of the enzymatic network driving the cell cycle, and oscillations in transcription factors such as NF-ΚB and tumor suppressors such as p53. Ilya Prigogine's concept of dissipative structures applies to temporal oscillations and allows us to unify within a common framework the various rhythms observed at different levels of biological organization, regardless of their period and underlying mechanism.

Mutation of von Hippel–Lindau Tumour Suppressor and Human Cardiopulmonary Physiology

PubMed Central

Smith, Thomas G; Brooks, Jerome T; Balanos, George M; Lappin, Terence R; Layton, D. Mark; Leedham, Dawn L; Liu, Chun; Maxwell, Patrick H; McMullin, Mary F; McNamara, Christopher J; Percy, Melanie J; Pugh, Christopher W; Ratcliffe, Peter J; Talbot, Nick P; Treacy, Marilyn; Robbins, Peter A

2006-01-01

Background The von Hippel–Lindau tumour suppressor protein–hypoxia-inducible factor (VHL–HIF) pathway has attracted widespread medical interest as a transcriptional system controlling cellular responses to hypoxia, yet insights into its role in systemic human physiology remain limited. Chuvash polycythaemia has recently been defined as a new form of VHL-associated disease, distinct from the classical VHL-associated inherited cancer syndrome, in which germline homozygosity for a hypomorphic VHL allele causes a generalised abnormality in VHL–HIF signalling. Affected individuals thus provide a unique opportunity to explore the integrative physiology of this signalling pathway. This study investigated patients with Chuvash polycythaemia in order to analyse the role of the VHL–HIF pathway in systemic human cardiopulmonary physiology. Methods and Findings Twelve participants, three with Chuvash polycythaemia and nine controls, were studied at baseline and during hypoxia. Participants breathed through a mouthpiece, and pulmonary ventilation was measured while pulmonary vascular tone was assessed echocardiographically. Individuals with Chuvash polycythaemia were found to have striking abnormalities in respiratory and pulmonary vascular regulation. Basal ventilation and pulmonary vascular tone were elevated, and ventilatory, pulmonary vasoconstrictive, and heart rate responses to acute hypoxia were greatly increased. Conclusions The features observed in this small group of patients with Chuvash polycythaemia are highly characteristic of those associated with acclimatisation to the hypoxia of high altitude. More generally, the phenotype associated with Chuvash polycythaemia demonstrates that VHL plays a major role in the underlying calibration and homeostasis of the respiratory and cardiovascular systems, most likely through its central role in the regulation of HIF. PMID:16768548

Physiology, production and action of progesterone.

PubMed

Taraborrelli, Stefania

2015-11-01

The aim of this article is to review the physiology of progesterone and focus on its physiological actions on tissues such as endometrium, uterus, mammary gland, cardiovascular system, central nervous system and bones. In the last decades, the interest of researchers has focused on the role of progesterone in genomic and non-genomic receptor mechanisms. We searched PubMed up to December 2014 for publications on progesterone/steroidogenesis. A better understanding of the biological genomic and non-genomic receptor mechanisms could enable us in the near future to obtain a more comprehensive knowledge of the safety and efficacy of this agent during hormone replacement therapy (natural progesterone), in vitro fertilization (water-soluble subcutaneous progesterone), in traumatic brain injury, Alzheimer's disease and diabetic neuropathy, even though further clinical studies are needed to prove its usefulness. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology.

Determinants of Physiological and Perceived Physiological Stress Reactivity in Children and Adolescents

PubMed Central

Evans, Brittany E.; Greaves-Lord, Kirstin; Euser, Anja S.; Tulen, Joke H. M.; Franken, Ingmar H. A.; Huizink, Anja C.

2013-01-01

Aims Abnormal physiological stress reactivity is increasingly investigated as a vulnerability marker for various physical and psychological health problems. However, studies are inconsistent in taking into account potential covariates that may influence the developing stress system. We systematically tested determinants (individual, developmental, environmental and substance use-related) of physiological and perceived physiological stress reactivity. We also examined the relation between physiological and perceived physiological stress reactivity. Method In a stratified sample of 363 children (7–12 years) and 344 adolescents (13–20 years) from the general population, we examined cortisol, heart rate, respiratory sinus arrhythmia and perceived physiological stress reactivity to a psychosocial stress procedure. Results Using multivariate linear regression models, we found that individual, developmental, environmental and substance use-related factors were related to each of the stress response indices. These determinant factors were different for each of the stress reactivity indices, and different in children versus adolescents. Perceived physiological stress reactivity predicted cortisol reactivity in adolescents only. All other relations between perceived physiological and physiological stress reactivity were not significant. Conclusions As physiological stress variables are often examined as vulnerability markers for the development of health problems, we maintain that it is essential that future studies take into consideration factors that may account for found relations. Our study provides an overview and indication of which variables should be considered in the investigation of the relation between physiological stress indices and illness. PMID:23620785

Anismus, Physiology, Radiology: Is It Time for Some Pragmatism? A Comparative Study of Radiological and Anorectal Physiology Findings in Patients With Anismus.

PubMed

Pisano, Umberto; Irvine, Lesley; Szczachor, Justina; Jawad, Ahsin; MacLeod, Andrew; Lim, Michael

2016-10-01

Anismus is a functional disorder featuring obstructive symptoms and paradoxical contractions of the pelvic floor. This study aims to establish diagnosis agreement between physiology and radiology, associate anismus with morphological outlet obstruction, and explore the role of sphincteric pressure and rectal volumes in the radiological diagnosis of anismus. Consecutive patients were evaluated by using magnetic resonance imaging proctography/fluoroscopic defecography and anorectal physiology. Morphological radiological features were associated with physiology tests. A categorical analysis was performed using the chi-square test, and agreement was assessed via the kappa coefficient. A Mann-Whitney test was used to assess rectal volumes and sphincterial pressure distributions between groups of patients. A P-value of <0.05 was significant. Forty-three patients (42 female patients) underwent anorectal physiology and radiology imaging. The median age was 54 years (interquartile range, 41.5-60 years). Anismus was seen radiologically and physiologically in 18 (41.8%) and 12 patients (27.9%), respectively. The agreement between modalities was 0.298 (P = 0.04). Using physiology as a reference, radiology had positive and negative predictive values of 44% and 84%, respectively. Rectoceles, cystoceles, enteroceles and pathological pelvic floor descent were not physiologically predictive of animus (P > 0.05). The sphincterial straining pressure was 71 mmHg in the anismus group versus 12 mmHg. Radiology was likely to identify anismus when the straining pressure exceeded 50% of the resting pressure (P = 0.08). Radiological techniques detect pelvic morphological abnormalities, but lead to overdiagnoses of anismus. No proctographic pathological feature predicts anismus reliably. A stronger pelvic floor paradoxical contraction is associated with a greater likelihood of detection by proctography.

Anismus, Physiology, Radiology: Is It Time for Some Pragmatism? A Comparative Study of Radiological and Anorectal Physiology Findings in Patients With Anismus

PubMed Central

Irvine, Lesley; Szczachor, Justina; Jawad, Ahsin; MacLeod, Andrew; Lim, Michael

2016-01-01

Purpose Anismus is a functional disorder featuring obstructive symptoms and paradoxical contractions of the pelvic floor. This study aims to establish diagnosis agreement between physiology and radiology, associate anismus with morphological outlet obstruction, and explore the role of sphincteric pressure and rectal volumes in the radiological diagnosis of anismus. Methods Consecutive patients were evaluated by using magnetic resonance imaging proctography/fluoroscopic defecography and anorectal physiology. Morphological radiological features were associated with physiology tests. A categorical analysis was performed using the chi-square test, and agreement was assessed via the kappa coefficient. A Mann-Whitney test was used to assess rectal volumes and sphincterial pressure distributions between groups of patients. A P-value of <0.05 was significant. Results Forty-three patients (42 female patients) underwent anorectal physiology and radiology imaging. The median age was 54 years (interquartile range, 41.5–60 years). Anismus was seen radiologically and physiologically in 18 (41.8%) and 12 patients (27.9%), respectively. The agreement between modalities was 0.298 (P = 0.04). Using physiology as a reference, radiology had positive and negative predictive values of 44% and 84%, respectively. Rectoceles, cystoceles, enteroceles and pathological pelvic floor descent were not physiologically predictive of animus (P > 0.05). The sphincterial straining pressure was 71 mmHg in the anismus group versus 12 mmHg. Radiology was likely to identify anismus when the straining pressure exceeded 50% of the resting pressure (P = 0.08). Conclusion Radiological techniques detect pelvic morphological abnormalities, but lead to overdiagnoses of anismus. No proctographic pathological feature predicts anismus reliably. A stronger pelvic floor paradoxical contraction is associated with a greater likelihood of detection by proctography. PMID:27847787

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

PubMed

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

2015-01-01

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

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

PubMed Central

Milne, Robyn; Cunningham, Susan J; Lee, Alan T K

2015-01-01

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

Perspective: Role of structure prediction in materials discovery and design

NASA Astrophysics Data System (ADS)

Needs, Richard J.; Pickard, Chris J.

2016-05-01

Materials informatics owes much to bioinformatics and the Materials Genome Initiative has been inspired by the Human Genome Project. But there is more to bioinformatics than genomes, and the same is true for materials informatics. Here we describe the rapidly expanding role of searching for structures of materials using first-principles electronic-structure methods. Structure searching has played an important part in unraveling structures of dense hydrogen and in identifying the record-high-temperature superconducting component in hydrogen sulfide at high pressures. We suggest that first-principles structure searching has already demonstrated its ability to determine structures of a wide range of materials and that it will play a central and increasing part in materials discovery and design.

Polyamines in plant physiology

NASA Technical Reports Server (NTRS)

Galston, A. W.; Sawhney, R. K.

1990-01-01

The diamine putrescine, the triamine spermidine, and the tetramine spermine are ubiquitous in plant cells, while other polyamines are of more limited occurrence. Their chemistry and pathways of biosynthesis and metabolism are well characterized. They occur in the free form as cations, but are often conjugated to small molecules like phenolic acids and also to various macromolecules. Their titer varies from approximately micromolar to more than millimolar, and depends greatly on environmental conditions, especially stress. In cereals, the activity of one of the major polyamine biosynthetic enzymes, arginine decarboxylase, is rapidly and dramatically increased by almost every studied external stress, leading to 50-fold or greater increases in putrescine titer within a few hours. The physiological significance of this increase is not yet clear, although most recent work suggests an adaptive, protective role. Polyamines produced through the action of ornithine decarboxylase, by contrast, seem essential for DNA replication and cell division. The application of exogenous polyamines produces effects on patterns of senescence and morphogenesis, suggesting but not proving a regulatory role for polyamines in these processes. The evidence for such a regulatory role is growing.

Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes: role of physiological fitness and microbial interactions.

PubMed

Albergaria, Helena; Arneborg, Nils

2016-03-01

Winemaking, brewing and baking are some of the oldest biotechnological processes. In all of them, alcoholic fermentation is the main biotransformation and Saccharomyces cerevisiae the primary microorganism. Although a wide variety of microbial species may participate in alcoholic fermentation and contribute to the sensory properties of end-products, the yeast S. cerevisiae invariably dominates the final stages of fermentation. The ability of S. cerevisiae to outcompete other microbial species during alcoholic fermentation processes, such as winemaking, has traditionally been ascribed to its high fermentative power and capacity to withstand the harsh environmental conditions, i.e. high levels of ethanol and organic acids, low pH values, scarce oxygen availability and depletion of certain nutrients. However, in recent years, several studies have raised evidence that S. cerevisiae, beyond its remarkable fitness for alcoholic fermentation, also uses defensive strategies mediated by different mechanisms, such as cell-to-cell contact and secretion of antimicrobial peptides, to combat other microorganisms. In this paper, we review the main physiological features underlying the special aptitude of S. cerevisiae for alcoholic fermentation and discuss the role of microbial interactions in its dominance during alcoholic fermentation, as well as its relevance for winemaking.

Biological underpinnings of breastfeeding challenges: the role of genetics, diet, and environment on lactation physiology

PubMed Central

Lee, Sooyeon

2016-01-01

Lactation is a dynamic process that has evolved to produce a complex biological fluid that provides nutritive and nonnutritive factors to the nursing offspring. It has long been assumed that once lactation is successfully initiated, the primary factor regulating milk production is infant demand. Thus, most interventions have focused on improving breastfeeding education and early lactation support. However, in addition to infant demand, increasing evidence from studies conducted in experimental animal models, production animals, and breastfeeding women suggests that a diverse array of maternal factors may also affect milk production and composition. In this review, we provide an overview of our current understanding of the role of maternal genetics and modifiable factors, such as diet and environmental exposures, on reproductive endocrinology, lactation physiology, and the ability to successfully produce milk. To identify factors that may affect lactation in women, we highlight some information gleaned from studies in experimental animal models and production animals. Finally, we highlight the gaps in current knowledge and provide commentary on future research opportunities aimed at improving lactation outcomes in breastfeeding women to improve the health of mothers and their infants. PMID:27354238

From discovery to function: the expanding roles of long noncoding RNAs in physiology and disease.

PubMed

Sun, Miao; Kraus, W Lee

2015-02-01

Long noncoding RNAs (lncRNAs) are a relatively poorly understood class of RNAs with little or no coding capacity transcribed from a set of incompletely annotated genes. They have received considerable attention in the past few years and are emerging as potentially important players in biological regulation. Here we discuss the evolving understanding of this new class of molecular regulators that has emerged from ongoing research, which continues to expand our databases of annotated lncRNAs and provide new insights into their physical properties, molecular mechanisms of action, and biological functions. We outline the current strategies and approaches that have been employed to identify and characterize lncRNAs, which have been instrumental in revealing their multifaceted roles ranging from cis- to trans-regulation of gene expression and from epigenetic modulation in the nucleus to posttranscriptional control in the cytoplasm. In addition, we highlight the molecular and biological functions of some of the best characterized lncRNAs in physiology and disease, especially those relevant to endocrinology, reproduction, metabolism, immunology, neurobiology, muscle biology, and cancer. Finally, we discuss the tremendous diagnostic and therapeutic potential of lncRNAs in cancer and other diseases.

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

Nonlinear dynamics, fractals, cardiac physiology and sudden death

NASA Technical Reports Server (NTRS)

Goldberger, Ary L.

1987-01-01

The authors propose a diametrically opposite viewpoint to the generally accepted tendency of equating healthy function with order and disease with chaos. With regard to the question of sudden cardiac death and chaos, it is suggested that certain features of dynamical chaos related to fractal structure and fractal dynamics may be important organizing principles in normal physiology and that certain pathologies, including ventricular fibrillation, represent a class of 'pathological periodicities'. Some laboratory work bearing on the relation of nonlinear analysis to physiological and pathophysiological data is briefly reviewed, with tentative theories and models described in reference to the mechanism of ventricular fibrillation.

Nasal Physiology

MedlinePlus

... Anatomy Virtual Anatomy Disclosure Statement Printer Friendly Nasal Physiology Jeremiah A. Alt, MD, PhD Noam Cohen, MD, ... control the inflammation. CONCLUSION An understanding of the physiology of the nose is critical to understand nasal ...

Physiological significance of TRPV2 as a mechanosensor, thermosensor and lipid sensor.

PubMed

Shibasaki, Koji

2016-09-01

This review provides a summary of the physiological significance of the TRPV2 ion channel. While TRPV2 was initially characterized as a noxious heat sensor, we found that TRPV2 can also act as a mechanosensor in embryonic neurons or adult myenteric neurons. Here, we summarize the newly characterized functions of TRPV2, including the research progress that has been made toward our understanding of TRPV2 physiology, and discuss other recent data pertaining to TRPV2. It is thought that TRPV2 may be an important drug target based on its broad expression patterns and important physiological roles. The possible associations between diseases and TRPV2 are also discussed.

Organizational Structuring of Sex Roles in a Nonstereotyped Industry

ERIC Educational Resources Information Center

Mennerick, Lewis A.

1975-01-01

Examines the occupation of travel agent, an occupation that is not sex-role stereotyped. Six measures were developed, revealing the existence of sex structuring of men and women in management and sales positions both among and within New York City travel agencies. (Author)

Crystal structure of a c-kit promoter quadruplex reveals the structural role of metal ions and water molecules in maintaining loop conformation.

PubMed

Wei, Dengguo; Parkinson, Gary N; Reszka, Anthony P; Neidle, Stephen

2012-05-01

We report here the 1.62 Å crystal structure of an intramolecular quadruplex DNA formed from a sequence in the promoter region of the c-kit gene. This is the first reported crystal structure of a promoter quadruplex and the first observation of localized magnesium ions in a quadruplex structure. The structure reveals that potassium and magnesium ions have an unexpected yet significant structural role in stabilizing particular quadruplex loops and grooves that is distinct from but in addition to the role of potassium ions in the ion channel at the centre of all quadruplex structures. The analysis also shows how ions cluster together with structured water molecules to stabilize the quadruplex arrangement. This particular quadruplex has been previously studied by NMR methods, and the present X-ray structure is in accord with the earlier topology assignment. However, as well as the observations of potassium and magnesium ions, the crystal structure has revealed a highly significant difference in the dimensions of the large cleft in the structure, which is a plausible target for small molecules. This difference can be understood by the stabilizing role of structured water networks.

Hunger Games: Interactive Ultrasound Imaging for Learning Gastrointestinal Physiology.

PubMed

Kafer, Ilana; Rennie, William; Noor, Ali; Pellerito, John S

2017-02-01

Ultrasound is playing an increasingly important role in medical student education. Although most uses of ultrasound have focused on learning purely anatomic relationships or augmentation of the physical examination, there is little documentation of the value of ultrasound as a learning tool regarding physiology alone or in association with anatomy. We devised an interactive learning session for first-year medical students using ultrasound to combine both anatomic and physiologic principles as an integration of gastrointestinal and vascular function. The incorporation of our activity, The Hunger Games, provides the foundation for a powerful integration tool for medical student education. © 2016 by the American Institute of Ultrasound in Medicine.

AKAP-scaffolding proteins and regulation of cardiac physiology

PubMed Central

Mauban, JRH; O'Donnell, M; Warrier, S; Manni, S; Bond, M

2009-01-01

A kinase anchoring proteins (AKAPs) compose a growing list of diverse but functionally related proteins defined by their ability to bind to the regulatory subunit of protein kinase A. AKAPs perform an integral role in the spatiotemporal modulation of a multitude of cellular signaling pathways. This review highlights the extensive role of AKAPs in cardiac excitation/contraction coupling and cardiac physiology. The literature shows that particular AKAPs are involved in cardiac Ca2+ influx, release, re-uptake, and myocyte repolarization. Studies have also suggested roles for AKAPs in cardiac remodeling. Transgenic studies show functional effects of AKAPs, not only in the cardiovascular system, but in other organ systems as well. PMID:19364910

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.

Physiological Factors Contributing to Postflight Changes in Functional Performance

NASA Technical Reports Server (NTRS)

Bloomberg, J. J.; Feedback, D. L.; Feiverson, A. H.; Lee, S. M. C.; Mulavara, A. P.; Peters, B. T.; Platts, S. H.; Reschke, M. F.; Ryder, J.; Spiering, B. A.;

Sirtuins in gamete biology and reproductive physiology: emerging roles and therapeutic potential in female and male infertility.

PubMed

Tatone, Carla; Di Emidio, Giovanna; Barbonetti, Arcangelo; Carta, Gaspare; Luciano, Alberto M; Falone, Stefano; Amicarelli, Fernanda

2018-05-01

Sirtuins (SIRT1-7) are a family of NAD+-dependent deacetylases that catalyze post-translational modifications of proteins. Together, they respond to metabolic challenges, inflammatory signals or hypoxic/oxidative stress, and are associated with aging and longevity. The role of Sirtuins in the regulation of fertility emerged in 2003 when a defective reproductive phenotype was observed in SIRT1-null mice. Although studies on Sirtuins in reproductive biology have been increasing in the last years, a recent comprehensive update on this issue is still lacking. This review is aimed to provide knowledge on the activation mechanism and cellular role of Sirtuins and to give an update of the rapid development of Sirtuin research in female and male reproduction under physiological and pathological conditions. The final goal is to assess whether strategies aimed to improve Sirtuin expression or activity could have therapeutic potential for infertility associated with polycystic ovarian syndrome (PCOS), endometriosis, diabetes, xenobiotic stress and aging. The MEDLINE database was examined for peer-reviewed original articles. The following keywords were searched: 'Sirtuin', 'ovary', 'oocyte', 'ovarian follicle', 'embryo', 'endometrium', 'sperm' and 'testis'. These keywords were combined with other search phrases relevant to the topic. Our knowledge of Sirtuins in reproductive functions has grown exponentially over the last few years. The majority of the work carried out so far has focused on SIRT1 with a prevalence of studies on female reproduction. Numerous studies have provided evidence that down-regulation of SIRT1 is associated with physiological or pathological reduction of ovarian reserve. SIRT1 has also been shown to regulate proliferation and apoptosis in granulosa cells whereas SIRT3 was found to promote luteinisation. Biochemical modulation of Sirtuin activity has led to discoveries of the roles of SIRT1, SIRT2, SIRT3 and SIRT6 in improving the competence of oocytes

Three-dimensional cryoEM reconstruction of native LDL particles to 16Å resolution at physiological body temperature.

PubMed

Kumar, Vibhor; Butcher, Sarah J; Öörni, Katariina; Engelhardt, Peter; Heikkonen, Jukka; Kaski, Kimmo; Ala-Korpela, Mika; Kovanen, Petri T

2011-05-09

Low-density lipoprotein (LDL) particles, the major carriers of cholesterol in the human circulation, have a key role in cholesterol physiology and in the development of atherosclerosis. The most prominent structural components in LDL are the core-forming cholesteryl esters (CE) and the particle-encircling single copy of a huge, non-exchangeable protein, the apolipoprotein B-100 (apoB-100). The shape of native LDL particles and the conformation of native apoB-100 on the particles remain incompletely characterized at the physiological human body temperature (37 °C). To study native LDL particles, we applied cryo-electron microscopy to calculate 3D reconstructions of LDL particles in their hydrated state. Images of the particles vitrified at 6 °C and 37 °C resulted in reconstructions at ~16 Å resolution at both temperatures. 3D variance map analysis revealed rigid and flexible domains of lipids and apoB-100 at both temperatures. The reconstructions showed less variability at 6 °C than at 37 °C, which reflected increased order of the core CE molecules, rather than decreased mobility of the apoB-100. Compact molecular packing of the core and order in a lipid-binding domain of apoB-100 were observed at 6 °C, but not at 37 °C. At 37 °C we were able to highlight features in the LDL particles that are not clearly separable in 3D maps at 6 °C. Segmentation of apoB-100 density, fitting of lipovitellin X-ray structure, and antibody mapping, jointly revealed the approximate locations of the individual domains of apoB-100 on the surface of native LDL particles. Our study provides molecular background for further understanding of the link between structure and function of native LDL particles at physiological body temperature.

Roles and Structures for Participation in Higher Education Governance: A Rationale.

ERIC Educational Resources Information Center

Ikenberry, Stanley O.

It is obvious that the roles for participation of faculty, students and administrators in campus governance are inadequately defined and that the organizational structure through which these roles might be performed is deficient. This paper considers the rationale for such faculty and student organizations and examines some issues that have to be…

Endogenous opioid systems: physiological role in the self-limitation of seizures.

PubMed

Tortella, F C; Long, J B; Holaday, J W

1985-04-15

Immediately following a seizure, the severity of subsequent seizures is significantly reduced. The involvement of endogenous opioid systems as a physiological regulator of this postseizure inhibition was studied in rats using repeated maximal electroshock (MES) seizures. Both the opiate antagonist (-)-naloxone and morphine tolerance abolished the progressive seizure protection associated with repeated MES. We propose that endogenous opioids, activated by a prior seizure, provide a central homeostatic inhibitory mechanism which may be responsible for the initiation of a postictal refractory state in the epileptic.

Spatial structure of the Mormon cricket gut microbiome and its predicted contribution to nutrition and immune function

USDA-ARS?s Scientific Manuscript database

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the n...

A Review of the Internal and External Physiological Demands Associated With Batting in Cricket.

PubMed

Scanlan, Aaron T; Berkelmans, Daniel M; Vickery, William M; Kean, Crystal O

2016-11-01

Cricket is a popular international team sport with various game formats ranging from long-duration multiday tests to short-duration Twenty20 game play. The role of batsmen is critical to all game formats, with differing physiological demands imposed during each format. Investigation of the physiological demands imposed during cricket batting has historically been neglected, with much of the research focusing on bowling responses and batting technique. A greater understanding of the physiological demands of the batting role in cricket is required to assist strength and conditioning professionals and coaches with the design of training plans, recovery protocols, and player-management strategies. This brief review provides an updated synthesis of the literature examining the internal (eg, metabolic demands and heart rate) and external (eg, activity work rates) physiological responses to batting in the various game formats, as well as simulated play and small-sided-games training. Although few studies have been done in this area, the summary of data provides important insight regarding physiological responses to batting and highlights that more research on this topic is required. Future research is recommended to combine internal and external measures during actual game play, as well as comparing different game formats and playing levels. In addition, understanding the relationship between batting technique and physiological responses is warranted to gain a more holistic understanding of batting in cricket, as well as to develop appropriate coaching and training strategies.

At the crossroads of physiology and ecology: food supply and the timing of avian reproduction.

PubMed

Davies, Scott; Deviche, Pierre

2014-06-01

This article is part of a Special Issue “Energy Balance”. The decision of when to breed is crucial to the reproductive success and fitness of seasonally breeding birds. The availability of food for adults prior to breeding has long been thought to play a critical role in timing the initiation of seasonal reproductive events, in particular laying. However, unequivocal evidence for such a role remains limited and the physiological mechanisms by which an increase in food availability results in seasonal activation of the reproductive system are largely speculative. This lack of mechanistic information partly reflects a lack of integration of ecological and physiological approaches to study seasonal reproduction. Indeed, most work pertaining to the role of food availability for adults on the timing of avian reproduction has been ecological and has focused almost exclusively on female traits associated with reproductive timing (e.g., lay date and clutch size). By contrast, most work on the physiological bases of the relationship between food availability and the timing of reproduction has investigated male traits associated with reproductive development (e.g., reproductive hormones and gonadal development). To advance our understanding of these topics, we review the role of proximate factors including food availability, social factors, and ambient temperature in the control of breeding decisions, and discuss the role of three potential candidates (leptin, glucocorticoids, and GnIH-neuropeptide Y) that may mediate the effects of food availability on these decisions. We emphasize that future progress in this area is heavily contingent upon the use of physiology-based approaches and their integration into current ecological frameworks. Published by Elsevier Inc.

Physiology of ejaculation: emphasis on serotonergic control.

PubMed

Giuliano, François; Clément, Pierre

2005-09-01

Ejaculation is constituted by two distinct phases, emission and expulsion. Orgasm, a feature perhaps unique in humans, is a cerebral process that occurs, in normal conditions, concomitantly to expulsion of semen. Normal antegrade ejaculation is a highly coordinated physiological process with emission and expulsion phases being under the control of autonomic and somatic nervous systems respectively. The central command of ejaculation is located at the thoracolumbar and lumbosacral levels of the spinal cord and is activated by stimuli from genital, mainly penile, origin although cerebral descending pathways exert both inhibitory and excitatory regulatory roles. Cerebral structures specifically activated during ejaculation form a tightly interconnected network comprising hypothalamic, diencephalic and pontine areas. A rational neurobiological approach has led to identify several neurotransmitters contributing to the ejaculatory process. Amongst them, serotonin (5-HT) has received strong experimental evidences indicating its inhibitory role in the central control of ejaculation. In particular, 5-HT1A cerebral autoreceptors but also spinal 5-HT1B and, in a lesser extent, 5-HT2C receptors have been shown to mediate the effects of 5-HT on ejaculation. Pharmacological strategies, especially those targeting serotonergic system, for the treatment of ejaculatory disorders in human will undoubtedly benefit from the application of basic and clinical research findings. In this perspective, the use of selective serotonin reuptake inhibitors (SSRIs) which basically increase the amount of central 5-HT and delay ejaculation in humans seems promising.

Harnessing glycomics technologies: integrating structure with function for glycan characterization

PubMed Central

Robinson, Luke N.; Artpradit, Charlermchai; Raman, Rahul; Shriver, Zachary H.; Ruchirawat, Mathuros; Sasisekharan, Ram

2013-01-01

Glycans, or complex carbohydrates, are a ubiquitous class of biological molecules which impinge on a variety of physiological processes ranging from signal transduction to tissue development and microbial pathogenesis. In comparison to DNA and proteins, glycans present unique challenges to the study of their structure and function owing to their complex and heterogeneous structures and the dominant role played by multivalency in their sequence-specific biological interactions. Arising from these challenges, there is a need to integrate information from multiple complementary methods to decode structure-function relationships. Focusing on acidic glycans, we describe here key glycomics technologies for characterizing their structural attributes, including linkage, modifications, and topology, as well as for elucidating their role in biological processes. Two cases studies, one involving sialylated branched glycans and the other sulfated glycosaminoglycans, are used to highlight how integration of orthogonal information from diverse datasets enables rapid convergence of glycan characterization for development of robust structure-function relationships. PMID:22522536

Lipoarabinomannan and related glycoconjugates: structure, biogenesis and role in Mycobacterium tuberculosis physiology and host–pathogen interaction

PubMed Central

Mishra, Arun K; Driessen, Nicole N; Appelmelk, Ben J; Besra, Gurdyal S

2011-01-01

Approximately one third of the world's population is infected with Mycobacterium tuberculosis, the causative agent of tuberculosis. This bacterium has an unusual lipid-rich cell wall containing a vast repertoire of antigens, providing a hydrophobic impermeable barrier against chemical drugs, thus representing an attractive target for vaccine and drug development. Apart from the mycolyl–arabinogalactan–peptidoglycan complex, mycobacteria possess several immunomodulatory constituents, notably lipomannan and lipoarabinomannan. The availability of whole-genome sequences of M. tuberculosis and related bacilli over the past decade has led to the identification and functional characterization of various enzymes and the potential drug targets involved in the biosynthesis of these glycoconjugates. Both lipomannan and lipoarabinomannan possess highly variable chemical structures, which interact with different receptors of the immune system during host–pathogen interactions, such as Toll-like receptors-2 and C-type lectins. Recently, the availability of mutants defective in the synthesis of these glycoconjugates in mycobacteria and the closely related bacterium, Corynebacterium glutamicum, has paved the way for host–pathogen interaction studies, as well as, providing attenuated strains of mycobacteria for the development of new vaccine candidates. This review provides a comprehensive account of the structure, biosynthesis and immunomodulatory properties of these important glycoconjugates. PMID:21521247

Stretch-activated TRPV2 channels: Role in mediating cardiopathies.

PubMed

Aguettaz, Elizabeth; Bois, Patrick; Cognard, Christian; Sebille, Stéphane

2017-11-01

Transient receptor potential vanilloid type 2, TRPV2, is a calcium-permeable cation channel belonging to the TRPV channel family. Although this channel has been first characterized as a noxious heat sensor, its mechanosensor property recently gained importance in various physiological functions. TRPV2 has been described as a stretch-mediated channel and a regulator of calcium homeostasis in several cell types and has been shown to be involved in the stretch-dependent responses in cardiomyocytes. Hence, several studies in the last years support the idea that TRPV2 play a key role in the function and structure of the heart, being involved in the cardiac compensatory mechanisms in response to pathologic or exercise-induced stress. We present here an overview of the current literature and concepts of TRPV2 channels involvement (i) in the mechanical coupling mechanisms in heart and (ii) in the mechanisms that lead to cardiomyopathies. All these studies lead us to think that TRPV2 may also be an important cardiac drug target based on its major physiological roles in heart. Copyright © 2017 Elsevier Ltd. All rights reserved.

Zinc and Wound Healing: A Review of Zinc Physiology and Clinical Applications.

PubMed

Kogan, Samuel; Sood, Aditya; Garnick, Mark S

2017-04-01

Our understanding of the role of zinc in normal human physiology is constantly expanding, yet there are major gaps in our knowledge with regard to the function of zinc in wound healing. This review aims to provide the clinician with sufficient understanding of zinc biology and an up-to-date perspective on the role of zinc in wound healing. Zinc is an essential ion that is crucial for maintenance of normal physiology, and zinc deficiency has many manifestations ranging from delayed wound healing to immune dysfunction and impairment of multiple sensory systems. While consensus has been reached regarding the detrimental effects of zinc deficiency on wound healing, there is considerable discord in the literature on the optimal methods and true benefits of zinc supplementation.

[K+ channels and lung epithelial physiology].

PubMed

Bardou, Olivier; Trinh, Nguyen Thu Ngan; Brochiero, Emmanuelle

2009-04-01

Transcripts of more than 30 different K(+) channels have been detected in the respiratory epithelium lining airways and alveoli. These channels belong to the 3 main classes of K(+) channels, i.e. i) voltage-dependent or calcium-activated, 6 transmembrane segments (TM), ii) 2-pores 4-TM and iii) inward-rectified 2-TM channels. The physiological and functional significance of this high molecular diversity of lung epithelial K(+) channels is not well understood. Surprisingly, relatively few studies are focused on K(+) channel function in lung epithelial physiology. Nevertheless, several studies have shown that KvLQT1, KCa and K(ATP) K(+) channels play a crucial role in ion and fluid transport, contributing to the control of airway and alveolar surface liquid composition and volume. K(+) channels are involved in other key functions, such as O(2) sensing or the capacity of the respiratory epithelia to repair after injury. This mini-review aims to discuss potential functions of lung K(+) channels.

A Matter of Life or Death: Untangling the Coupled Roles of Behavior, Microclimate and Physiological Polymorphism in Governing Vulnerability of Intertidal Snails to Heat Stress

NASA Astrophysics Data System (ADS)

Dong, Y.; Li, X.; Choi, F.; Willams, G.; Somero, G. N.; Helmuth, B.

2016-12-01

Changing patterns of species' biogeographic distributions are driven by cumulative effects of much smaller scale processes. Specifically, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature (Tb), local microclimatic conditions, and abilities to anticipate extreme conditions and move to cooler refugia. These variables have rarely been quantified simultaneously over large geographic scales. We analyzed the thermal tolerances of three species of rocky intertidal snails from eight sites spanning 11.5 degrees of latitude along the Chinese coast. Using a biophysical model, we estimated potential Tb in sun-exposed and shaded microhabitats for all species at these sites for 30 years. We then compared maximum predicted Tb against the temperatures at which cardiac function was impaired (Arrhenius Break Temperatures, ABT) and lethal limits were reached (cardiac Flat Line Temperatures, FLT) to calculate thermal Safety Margins (TSM) for normal physiological function (TSMABT) and heat death (TSMFLT). Regular exceedance of FLT in sun-exposed microhabitats was predicted for only one site in the middle of the geographic gradient. However, ABT was exceeded at sun-exposed microhabitats in most sites, suggesting significant physiological impairment for snails that fail to move into the shade. An autocorrelation analysis of snail Tb showed that predictability of extreme temperatures was lowest at the hottest sites, an indication that reliance on behavioral thermoregulation may be a risky strategy. Observed large differences in ABT and FLT among conspecifics emphasize the critical role of physiological polymorphisms in governing the vulnerability of populations to heat stress.

Immunomodulation: A definitive role of microRNA-142.

PubMed

Sharma, Salil

2017-12-01

Majority of microRNAs are evolutionarily conserved in vertebrates. This is suggestive of their similar roles in regulation of gene networks. In addition to their conserved mature sequences and regulatory roles, a few microRNAs show very cell or tissue specific expression. These microRNAs are highly enriched in some cell types or organs. One such microRNA is microRNA-142 (miR-142). The classical stem-loop structure of miR142 encodes for two species of mature microRNAs; miR142-5p and miR142-3p. MiR-142 is abundant in cells of hematopoietic origin, and therefore, aptly plays a role in lineage differentiation of hematopoietic cells. Interestingly, over the years, miR-142 has gained considerable attention for its quintessential role in regulating immune response. This mini-review discusses the important functional roles of miR-142 in inflammatory and immune response in different physiological and disease setting. Copyright © 2017 Elsevier Ltd. All rights reserved.

Long-term effects of neonatal hypoxia-ischemia on structural and physiological integrity of the eye and visual pathway by multimodal MRI.

PubMed

Chan, Kevin C; Kancherla, Swarupa; Fan, Shu-Juan; Wu, Ed X

2014-12-09

Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways. Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner. Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres. High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Long-Term Effects of Neonatal Hypoxia-Ischemia on Structural and Physiological Integrity of the Eye and Visual Pathway by Multimodal MRI

PubMed Central

Chan, Kevin C.; Kancherla, Swarupa; Fan, Shu-Juan; Wu, Ed X.

2015-01-01

Purpose. Neonatal hypoxia-ischemia is a major cause of brain damage in infants and may frequently present visual impairments. Although advancements in perinatal care have increased survival, the pathogenesis of hypoxic-ischemic injury and the long-term consequences to the visual system remain unclear. We hypothesized that neonatal hypoxia-ischemia can lead to chronic, MRI-detectable structural and physiological alterations in both the eye and the brain's visual pathways. Methods. Eight Sprague-Dawley rats underwent ligation of the left common carotid artery followed by hypoxia for 2 hours at postnatal day 7. One year later, T2-weighted MRI, gadolinium-enhanced MRI, chromium-enhanced MRI, manganese-enhanced MRI, and diffusion tensor MRI (DTI) of the visual system were evaluated and compared between opposite hemispheres using a 7-Tesla scanner. Results. Within the eyeball, systemic gadolinium administration revealed aqueous-vitreous or blood-ocular barrier leakage only in the ipsilesional left eye despite comparable aqueous humor dynamics in the anterior chamber of both eyes. Binocular intravitreal chromium injection showed compromised retinal integrity in the ipsilesional eye. Despite total loss of the ipsilesional visual cortex, both retinocollicular and retinogeniculate pathways projected from the contralesional eye toward ipsilesional visual cortex possessed stronger anterograde manganese transport and less disrupted structural integrity in DTI compared with the opposite hemispheres. Conclusions. High-field, multimodal MRI demonstrated in vivo the long-term structural and physiological deficits in the eye and brain's visual pathways after unilateral neonatal hypoxic-ischemic injury. The remaining retinocollicular and retinogeniculate pathways appeared to be more vulnerable to anterograde degeneration from eye injury than retrograde, transsynaptic degeneration from visual cortex injury. PMID:25491295

Coping with Unemployment: Personality, Role Demands, and Time Structure

ERIC Educational Resources Information Center

Van Hoye, Greet; Lootens, Hanne

2013-01-01

Time structure has been found to be an important coping mechanism for dealing with the negative effects of unemployment on psychological well-being. This study extends the literature by investigating personality (openness to experience, conscientiousness, extraversion, neuroticism, and proactivity) and role demands (marital status, being the only…

The physiology analysis system: an integrated approach for warehousing, management and analysis of time-series physiology data.

PubMed

McKenna, Thomas M; Bawa, Gagandeep; Kumar, Kamal; Reifman, Jaques

2007-04-01

The physiology analysis system (PAS) was developed as a resource to support the efficient warehousing, management, and analysis of physiology data, particularly, continuous time-series data that may be extensive, of variable quality, and distributed across many files. The PAS incorporates time-series data collected by many types of data-acquisition devices, and it is designed to free users from data management burdens. This Web-based system allows both discrete (attribute) and time-series (ordered) data to be manipulated, visualized, and analyzed via a client's Web browser. All processes occur on a server, so that the client does not have to download data or any application programs, and the PAS is independent of the client's computer operating system. The PAS contains a library of functions, written in different computer languages that the client can add to and use to perform specific data operations. Functions from the library are sequentially inserted into a function chain-based logical structure to construct sophisticated data operators from simple function building blocks, affording ad hoc query and analysis of time-series data. These features support advanced mining of physiology data.

[The physiology of glucagon-like peptide-1 and its role in the pathophysiology of type 2 diabetes mellitus].

PubMed

Escalada, Francisco Javier

2014-01-01

The hormone glucagon-like peptide-1 (GLP-1) is synthesized and secreted by L cells in the small intestine in response to food ingestion. After reaching the general circulation it has a half-life of 2-3 minutes due to degradation by the enzyme dipeptidyl peptidase-4. Its physiological role is directed to control plasma glucose concentration, though GLP-1 also plays other different metabolic functions following nutrient absorption. Biological activities of GLP-1 include stimulation of insulin biosynthesis and glucose-dependent insulin secretion by pancreatic beta cell, inhibition of glucagon secretion, delay of gastric emptying and inhibition of food intake. GLP-1 is able to reduce plasma glucose levels in patients with type 2 diabetes and also can restore beta cell sensitivity to exogenous secretagogues, suggesting that the increasing GLP-1 concentration may be an useful therapeutic strategy for the treatment of patients with type 2 diabetes.

Neural Correlates of Emotional Personality: A Structural and Functional Magnetic Resonance Imaging Study

PubMed Central

Koelsch, Stefan; Skouras, Stavros; Jentschke, Sebastian

2013-01-01

Studies addressing brain correlates of emotional personality have remained sparse, despite the involvement of emotional personality in health and well-being. This study investigates structural and functional brain correlates of psychological and physiological measures related to emotional personality. Psychological measures included neuroticism, extraversion, and agreeableness scores, as assessed using a standard personality questionnaire. As a physiological measure we used a cardiac amplitude signature, the so-called E κ value (computed from the electrocardiogram) which has previously been related to tender emotionality. Questionnaire scores and E κ values were related to both functional (eigenvector centrality mapping, ECM) and structural (voxel-based morphometry, VBM) neuroimaging data. Functional magnetic resonance imaging (fMRI) data were obtained from 22 individuals (12 females) while listening to music (joy, fear, or neutral music). ECM results showed that agreeableness scores correlated with centrality values in the dorsolateral prefrontal cortex, the anterior cingulate cortex, and the ventral striatum (nucleus accumbens). Individuals with higher E κ values (indexing higher tender emotionality) showed higher centrality values in the subiculum of the right hippocampal formation. Structural MRI data from an independent sample of 59 individuals (34 females) showed that neuroticism scores correlated with volume of the left amygdaloid complex. In addition, individuals with higher E κ showed larger gray matter volume in the same portion of the subiculum in which individuals with higher E κ showed higher centrality values. Our results highlight a role of the amygdala in neuroticism. Moreover, they indicate that a cardiac signature related to emotionality (E κ) correlates with both function (increased network centrality) and structure (grey matter volume) of the subiculum of the hippocampal formation, suggesting a role of the hippocampal formation for

Use of concept mapping in an undergraduate introductory exercise physiology course.

PubMed

Henige, Kim

2012-09-01

Physiology is often considered a challenging course for students. It is up to teachers to structure courses and create learning opportunities that will increase the chance of student success. In an undergraduate exercise physiology course, concept maps are assigned to help students actively process and organize information into manageable and meaningful chunks and to teach them to recognize the patterns and regularities of physiology. Students are first introduced to concept mapping with a commonly relatable nonphysiology concept and are then assigned a series of maps that become more and more complex. Students map the acute response to a drop in blood pressure, the causes of the acute increase in stroke volume during cardiorespiratory exercise, and the factors contributing to an increase in maximal O(2) consumption with cardiorespiratory endurance training. In the process, students draw the integrative nature of physiology, identify causal relationships, and learn about general models and core principles of physiology.

The Impact of Protein Phosphorylation on Chlamydial Physiology

PubMed Central

Claywell, Ja E.; Matschke, Lea M.; Fisher, Derek J.

2016-01-01

Chlamydia are Gram negative bacterial pathogens responsible for disease in humans and economically important domesticated animals. As obligate intracellular bacteria, they must gain entry into a host cell where they propagate within a parasitophorous organelle that serves as an interactive interface between the bacterium and the host. Nutrient acquisition, growth, and evasion of host defense mechanisms occur from this location. In addition to these cellular and bacterial dynamics, Chlamydia differentiate between two morphologically distinct forms, the elementary body and reticulate body, that are optimized for either extracellular or intracellular survival, respectively. The mechanisms regulating and mediating these diverse physiological events remain largely unknown. Reversible phosphorylation, including classical two-component signaling systems, partner switching mechanisms, and the more recently appreciated bacterial Ser/Thr/Tyr kinases and phosphatases, has gained increasing attention for its role in regulating important physiological processes in bacteria including metabolism, development, and virulence. Phosphorylation modulates these events via rapid and reversible modification of protein substrates leading to changes in enzyme activity, protein oligomerization, cell signaling, and protein localization. The characterization of several conserved chlamydial protein kinases and phosphatases along with phosphoproteome analysis suggest that Chlamydia are capable of global and growth stage-specific protein phosphorylation. This mini review will highlight the current knowledge of protein phosphorylation in Chlamydia and its potential role in chlamydial physiology and, consequently, virulence. Comparisons with other minimal genome intracellular bacterial pathogens also will be addressed with the aim of illustrating the importance of this understudied regulatory mechanism on pathogenesis and the principle questions that remain unanswered. PMID:28066729

Attributing Increased River Flooding in the Future: Hydrodynamic Downscaling Reveals Role of Plant Physiological Responses to Increased CO2 is First Order

NASA Astrophysics Data System (ADS)

Fowler, M. D.; Kooperman, G. J.; Pritchard, M. S.; Randerson, J. T.

2017-12-01

River flooding events, which are the most frequently occurring natural disaster today, are expected to become more frequent and intense in response to climate change. However, the magnitude of these changes remains debated, in part due to uncertainty in our understanding of the physical processes that contribute to these events and their representation in global climate models. While the intensification of precipitation has been shown to be a primary driver of increased flooding, plant physiological responses to increasing CO2 may also play an important role. As the atmospheric concentration of CO2 increases, plants may respond by reducing the width of their stomata (i.e. stomatal conductance), which can decrease water lost through transpiration and in turn maintain higher soil moisture levels. On long timescales, reduced transpiration has been shown to increase average runoff, but on short timescales elevated soil moisture can also increase instantaneous runoff by limiting the rate at which water is able to infiltrate the soil surface. Here, through hydrodynamic downscaling, we isolate the portion of flooding amplification that can be attributed to the physiological response to increasing CO2. This builds on a new analysis that has revealed such physiological effects can rival changes caused by the atmospheric response alone in the tails of the runoff distribution. We use a set of four simulations run with the Community Earth System Model: one pre-industrial control simulation and three others that are forced with four times CO2. In the three climate change simulations, the increased CO2 is applied only to the land-surface, only to the atmosphere, and to both, respectively. Thirty years of daily runoff from these experiments are used as input for the hydrodynamic CaMa-Flood model. Our results reveal that both the radiative and physiological responses to climate change contribute significantly to future changes in flood return period and inundated area. This

The physiology of a local renin-angiotensin system in the pancreas.

PubMed

Leung, Po Sing

2007-04-01

The systemic renin-angiotensin system (RAS) plays an important role in regulating blood pressure, electrolyte and fluid homeostasis. However, local RASs also exist in diverse tissues and organs, where they play a multitude of autocrine, paracrine and intracrine physiological roles. The existence of a local RAS is now recognized in pancreatic acinar, islet, duct, endothelial and stellate cells, the expression of which is modulated in response to physiological and pathophysiological stimuli such as hypoxia, pancreatitis, islet transplantation, hyperglycaemia, and diabetes mellitus. This pancreatic RAS has been proposed to have important endocrine and exocrine roles in the pancreas, regulating local blood flow, duct cell sodium bicarbonate secretion, acinar cell digestive enzyme secretion, islet beta-cell (pro)insulin biosynthesis, and thus, glucose-stimulated insulin release, delta-cell somatostatin secretion, and pancreatic cell proliferation and differentiation. It may further mediate oxidative stress-induced cell inflammation, apoptosis and fibrosis. Further exploration of this system would probably offer new insights into the pathogenesis of pancreatitis, diabetes, cystic fibrosis and pancreatic cancer formation. New therapeutic targets and strategies might thus be suggested.

The physiology of a local renin–angiotensin system in the pancreas

PubMed Central

Leung, Po Sing

2007-01-01

The systemic renin–angiotensin system (RAS) plays an important role in regulating blood pressure, electrolyte and fluid homeostasis. However, local RASs also exist in diverse tissues and organs, where they play a multitude of autocrine, paracrine and intracrine physiological roles. The existence of a local RAS is now recognized in pancreatic acinar, islet, duct, endothelial and stellate cells, the expression of which is modulated in response to physiological and pathophysiological stimuli such as hypoxia, pancreatitis, islet transplantation, hyperglycaemia, and diabetes mellitus. This pancreatic RAS has been proposed to have important endocrine and exocrine roles in the pancreas, regulating local blood flow, duct cell sodium bicarbonate secretion, acinar cell digestive enzyme secretion, islet beta-cell (pro)insulin biosynthesis, and thus, glucose-stimulated insulin release, delta-cell somatostatin secretion, and pancreatic cell proliferation and differentiation. It may further mediate oxidative stress-induced cell inflammation, apoptosis and fibrosis. Further exploration of this system would probably offer new insights into the pathogenesis of pancreatitis, diabetes, cystic fibrosis and pancreatic cancer formation. New therapeutic targets and strategies might thus be suggested. PMID:17218353

Molecular structure of P2X receptors.

PubMed

Egan, Terrance M; Cox, Jane A; Voigt, Mark M

2004-01-01

P2X receptors are ligand-gated ion channels that transduce many of the physiological effects of extracellular ATP. There has been a dramatic increase in awareness of these receptors over the past 5 or so years, in great part due to their molecular cloning and characterization. The availability of cDNA clones for the various subunits has led to rapid progress in identifying their tissue-specific expression, resulting in new ideas concerning the functional roles these receptors might play in physiological and pathophysiological processes. In addition, molecular approaches have yielded much information regarding the structure and function of the receptor proteins themselves. In this review we seek to review recent findings concerning the molecular determinants of receptor-channel function, with particular focus on ligand binding and gating, ion selectivity, and subunit assembly.

Physiological characteristics of bacteria isolated from water brines within permafrost

NASA Astrophysics Data System (ADS)

Shcherbakova, V.; Rivkina, E.; Laurinavichuis, K.; Pecheritsina, S.; Gilichinsky, D.

2004-01-01

In the Arctic there are lenses of overcooled water brines (cryopegs) sandwiched within permafrost marine sediments 100 120 thousand years old. We have investigated the physiological properties of the pure cultures of anaerobic Clostridium sp. strain 14D1 and two strains of aerobic bacteria Psychrobacter sp. isolated from these cryopegs. The structural and physiological characteristics of new bacteria from water brines have shown their ability to survive and develop under harsh conditions, such as subzero temperatures and high salinity.

Teaching a changing paradigm in physiology: a historical perspective on gut interstitial cells.

PubMed

Drumm, Bernard T; Baker, Salah A

2017-03-01

The study and teaching of gastrointestinal (GI) physiology necessitates an understanding of the cellular basis of contractile and electrical coupling behaviors in the muscle layers that comprise the gut wall. Our knowledge of the cellular origin of GI motility has drastically changed over the last 100 yr. While the pacing and coordination of GI contraction was once thought to be solely attributable to smooth muscle cells, it is now widely accepted that the motility patterns observed in the GI tract exist as a result of a multicellular system, consisting of not only smooth muscle cells but also enteric neurons and distinct populations of specialized interstitial cells that all work in concert to ensure proper GI functions. In this historical perspective, we focus on the emerging role of interstitial cells in GI motility and examine the key discoveries and experiments that led to a major shift in a paradigm of GI physiology regarding the role of interstitial cells in modulating GI contractile patterns. A review of these now classic experiments and papers will enable students and educators to fully appreciate the complex, multicellular nature of GI muscles as well as impart lessons on how shifting paradigms in physiology are fueled by new technologies that lead to new emerging discoveries. Copyright © 2017 the American Physiological Society.

The Plant Polyester Cutin: Biosynthesis, Structure, and Biological Roles.

PubMed

Fich, Eric A; Segerson, Nicholas A; Rose, Jocelyn K C

2016-04-29

Cutin, a polyester composed mostly of oxygenated fatty acids, serves as the framework of the plant cuticle. The same types of cutin monomers occur across most plant lineages, although some evolutionary trends are evident. Additionally, cutins from some species have monomer profiles that are characteristic of the related polymer suberin. Compositional differences likely have profound structural consequences, but little is known about cutin's molecular organization and architectural heterogeneity. Its biological importance is suggested by the wide variety of associated mutants and gene-silencing lines that show a disruption of cuticular integrity, giving rise to numerous physiological and developmental abnormalities. Mapping and characterization of these mutants, along with suppression of gene paralogs through RNA interference, have revealed much of the biosynthetic pathway and several regulatory factors; however, the mechanisms of cutin polymerization and its interactions with other cuticle and cell wall components are only now beginning to be resolved.

Androgen receptor: structure, role in prostate cancer and drug discovery

PubMed Central

Tan, MH Eileen; Li, Jun; Xu, H Eric; Melcher, Karsten; Yong, Eu-leong

2015-01-01

Androgens and androgen receptors (AR) play a pivotal role in expression of the male phenotype. Several diseases, such as androgen insensitivity syndrome (AIS) and prostate cancer, are associated with alterations in AR functions. Indeed, androgen blockade by drugs that prevent the production of androgens and/or block the action of the AR inhibits prostate cancer growth. However, resistance to these drugs often occurs after 2–3 years as the patients develop castration-resistant prostate cancer (CRPC). In CRPC, a functional AR remains a key regulator. Early studies focused on the functional domains of the AR and its crucial role in the pathology. The elucidation of the structures of the AR DNA binding domain (DBD) and ligand binding domain (LBD) provides a new framework for understanding the functions of this receptor and leads to the development of rational drug design for the treatment of prostate cancer. An overview of androgen receptor structure and activity, its actions in prostate cancer, and how structural information and high-throughput screening have been or can be used for drug discovery are provided herein. PMID:24909511

Correlation between plant physiology and CO2 removable

NASA Astrophysics Data System (ADS)

Leman, A. M.; Shamsuri, Mohd Mahathir Suhaimi; Hariri, Azian; Kadir, Aeslina Abdul; Idris, Ahmad Fu'ad; Afandi, Azizi

2017-09-01

Certain plants that are able to live in the building are known as indoor plants. Plants have tolerance with indoor environment in order to survive. Usually these plants are able to improve indoor air quality (IAQ). Absorption of carbon dioxide (CO2) by plants is one of the indicators that plants are still alive during photosynthesis process. The possibility of plants structure (plant physiology) to affect CO2 absorption had been the concerns of former researchers. This research intends to study the significant of plant structure (leaf area, fresh weight, and dry weight) that leads to reducing the concentration of CO2 by seven plant species (Anthurium, Dumb Cane, Golden Pothos, Kadaka Fern, Prayer Plants, Spider Plants, and Syngonium). The data of CO2 reduction by plants has been obtained from previous studies. Based on results show that, the leaf area is the most contributing the significant effect to the plant absorb CO2 compare to fresh weight and dry weight. It can be prove by Pearson Correlation, where only the value of leaf area is more than 0.5 for every four conditions. This study can be conclude that the leaf area is quite plays an important role to the plant treat air from CO2, while concentration of light and CO2 will become catalytic factor for the plants improve their photosynthesis process.

Store-operated Ca2+ entry in muscle physiology and diseases

PubMed Central

Pan, Zui; Brotto, Marco; Ma, Jianjie

2014-01-01

Ca2+ release from intracellular stores and influx from extracellular reservoir regulate a wide range of physiological functions including muscle contraction and rhythmic heartbeat. One of the most ubiquitous pathways involved in controlled Ca2+ influx into cells is store-operated Ca2+ entry (SOCE), which is activated by the reduction of Ca2+ concentration in the lumen of endoplasmic or sarcoplasmic reticulum (ER/SR). Although SOCE is pronounced in non-excitable cells, accumulating evidences highlight its presence and important roles in skeletal muscle and heart. Recent discovery of STIM proteins as ER/SR Ca2+ sensors and Orai proteins as Ca2+ channel pore forming unit expedited the mechanistic understanding of this pathway. This review focuses on current advances of SOCE components, regulation and physiologic and pathophysiologic roles in muscles. The specific property and the dysfunction of this pathway in muscle diseases, and new directions for future research in this rapidly growing field are discussed. [BMB Reports 2014; 47(2): 69-79] PMID:24411466

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.

The earliest history of diaphragm physiology.

PubMed

Derenne, J P; Debru, A; Grassino, A E; Whitelaw, W A

1994-12-01

The diaphragm was recognized as a distinct anatomical structure in the earliest Greek writings. However, the precise description of wounds suffered by warriors during the Trojan war by Homer was not tied to any particular function. The diaphragm was assimilated to the region that harbours thought. The first physiologic explanations of respiration by Empedocles in the 5th century BC and the concepts introduced by Plato and Hippocrates did not include a significant participation of the diaphragm. Aristole was the first to link respiration to a particular organ and a specific movement of the thorax. However, he considered that it was the heart which caused the lungs to expand by heating them, and the lungs in turn forced the thorax to dilate, a concept which was to survive until the 17th century. As in Aristole's theory the diaphragm played no role in respiration and was just a fence separating the thorax from the abdomen. A major break through occurred in Alexandria in the 4th and 3rd century BC: Herophilus was the first to recognize that muscles were the agents of movement and Erasistratus performed animal experiments which showed that the respiratory muscles were the agents of respiratory movements, thus opening the way to the later discoveries of Galen.

Uncovering Novel Roles of Nonneuronal Cells in Body Weight Homeostasis and Obesity

PubMed Central

Argente, Jesús

2013-01-01

Glial cells, which constitute more than 50% of the mass of the central nervous system and greatly outnumber neurons, are at the vanguard of neuroendocrine research in metabolic control and obesity. Historically relegated to roles of structural support and protection, diverse functions have been gradually attributed to this heterogeneous class of cells with their protagonism in crescendo in all areas of neuroscience during the past decade. However, this dramatic increase in attention bestowed upon glial cells has also emphasized our vast lack of knowledge concerning many aspects of their physiological functions, let alone their participation in numerous pathologies. This minireview focuses on the recent advances in our understanding of how glial cells participate in the physiological regulation of appetite and systemic metabolism as well as their role in the pathophysiological response to poor nutrition and secondary complications associated with obesity. Moreover, we highlight some of the existing lagoons of knowledge in this increasingly important area of investigation. PMID:23798599

The use of team-based, guided inquiry learning to overcome educational disadvantages in learning human physiology: a structural equation model.

PubMed

Rathner, Joseph A; Byrne, Graeme

2014-09-01

The study of human bioscience is viewed as a crucial curriculum in allied health. Nevertheless, bioscience (and particularly physiology) is notoriously difficult for undergraduates, particularly academically disadvantaged students. So endemic are the high failure rates (particularly in nursing) that it has come to be known as "the human bioscience problem." In the present report, we describe the outcomes for individual success in studying first-year human physiology in a subject that emphasises team-based active learning as the major pedagogy for mastering subject learning outcomes. Structural equation modeling was used to develop a model of the impact team learning had on individual performance. Modeling was consistent with the idea that students with similar academic abilities (as determined by tertiary entrance rank) were advantaged (scored higher on individual assessment items) by working in strong teams (teams that scored higher in team-based assessments). Analysis of covariance revealed that students who studied the subject with active learning as the major mode of learning activities outperformed students who studied the subject using the traditional didactic teaching format (lectures and tutorials, P = 0.000). After adjustment for tertiary entrance rank (via analysis of covariance) on two individual tests (the final exam and a late-semester in-class test), individual student grades improved by 8% (95% confidence interval: 6-10%) and 12% (95% confidence interval: 10-14%) when students engaged in team-based active learning. These data quantitatively support the notion that weaker students working in strong teams can overcome their educational disadvantages. Copyright © 2014 The American Physiological Society.

STRUCTURED LEARNING AND TRAINING ENVIRONMENTS--A PREPARATION LABORATORY FOR ADVANCED MAMMALIAN PHYSIOLOGY.

ERIC Educational Resources Information Center

FIEL, NICHOLAS J.; JOHNSTON, RAYMOND F.

A PREPARATION LABORATORY WAS DESIGNED TO FAMILIARIZE STUDENTS IN ADVANCED MAMMALIAN PHYSIOLOGY WITH LABORATORY SKILLS AND TECHNIQUES AND THUS SHORTEN THE TIME THEY SPEND IN SETTING UP ACTUAL EXPERIMENTS. THE LABORATORY LASTS 30 MINUTES, IS FLEXIBLE AND SIMPLE OF OPERATION, AND DOES NOT REQUIRE A PROFESSOR'S PRESENCE. THE BASIC TRAINING UNIT IS THE…

Physiological stress reactivity and physical and relational aggression: the moderating roles of victimization, type of stressor, and child gender.

PubMed

Murray-Close, Dianna; Crick, Nicki R; Tseng, Wan-Ling; Lafko, Nicole; Burrows, Casey; Pitula, Clio; Ralston, Peter

2014-08-01

The purpose of the present investigation was to examine the association between physiological reactivity to peer stressors and physical and relational aggression. Potential moderation by actual experiences of peer maltreatment (i.e., physical and relational victimization) and gender were also explored. One hundred ninety-six children (M = 10.11 years, SD = 0.64) participated in a laboratory stress protocol during which their systolic blood pressure, diastolic blood pressure, and skin conductance reactivity to recounting a relational stressor (e.g., threats to relationships) and an instrumental stressor (e.g., threats to physical well-being, dominance, or property) were assessed. Teachers provided reports of aggression and victimization. In both boys and girls, physical aggression was associated with blunted physiological reactivity to relational stress and heightened physiological reactivity to instrumental stress, particularly among youth higher in victimization. In girls, relational aggression was most robustly associated with blunted physiological reactivity to relational stressors, particularly among girls exhibiting higher levels of relational victimization. In boys, relational aggression was associated with heightened physiological reactivity to both types of stressors at higher levels of peer victimization and blunted physiological reactivity to both types of stressors at lower levels of victimization. Results underscore the shared and distinct emotional processes underlying physical and relational aggression in boys and girls.

Regulation and physiological functions of mammalian phospholipase C.

PubMed

Nakamura, Yoshikazu; Fukami, Kiyoko

2017-04-01

Phospholipase C (PLC) is a key enzyme in phosphoinositide metabolism. PLC hydrolyses phosphatidylinositol 4,5-bis-phosphate to generate two second messengers, inositol 1,4,5-trisphosphate and diacylglycerol, that generate diverse cellular responses. PLC is activated by various signalling molecules, including Ca2+, heterometric G proteins, small G proteins, and receptor/non-receptor tyrosine kinases. In addition to their enzymatic activity, some PLC subtypes also function as a guanine nucleotide exchange factor, GTPase-activating protein, and adaptor protein, independent of their lipase activity. There are 13 PLC isozymes in mammals, and they are categorized into six classes based on structure. Generation and analysis of genetically modified mice has revealed the unexpectedly diverse physiological functions of PLC isozymes. Although all PLC isozymes catalyze the same reaction, each PLC isozyme has unique physiological functions. This review focuses on the regulation and physiological functions of PLCs. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Visual perception and regulatory conflict: motivation and physiology influence distance perception.

PubMed

Cole, Shana; Balcetis, Emily; Zhang, Sam

2013-02-01

Regulatory conflict can emerge when people experience a strong motivation to act on goals but a conflicting inclination to withhold action because physical resources available, or physiological potentials, are low. This study demonstrated that distance perception is biased in ways that theory suggests assists in managing this conflict. Participants estimated the distance to a target location. Individual differences in physiological potential measured via waist-to-hip ratio interacted with manipulated motivational states to predict visual perception. Among people low in physiological potential and likely to experience regulatory conflict, the environment appeared easier to traverse when motivation was strong compared with weak. Among people high in potential and less likely to experience conflict, perception was not predicted by motivational strength. The role of motivated distance perception in self-regulation is discussed. 2013 APA, all rights reserved

Rowing Physiology.

ERIC Educational Resources Information Center

Spinks, W. L.

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

Physiological models of the lateral superior olive

PubMed Central

2017-01-01

In computational biology, modeling is a fundamental tool for formulating, analyzing and predicting complex phenomena. Most neuron models, however, are designed to reproduce certain small sets of empirical data. Hence their outcome is usually not compatible or comparable with other models or datasets, making it unclear how widely applicable such models are. In this study, we investigate these aspects of modeling, namely credibility and generalizability, with a specific focus on auditory neurons involved in the localization of sound sources. The primary cues for binaural sound localization are comprised of interaural time and level differences (ITD/ILD), which are the timing and intensity differences of the sound waves arriving at the two ears. The lateral superior olive (LSO) in the auditory brainstem is one of the locations where such acoustic information is first computed. An LSO neuron receives temporally structured excitatory and inhibitory synaptic inputs that are driven by ipsi- and contralateral sound stimuli, respectively, and changes its spike rate according to binaural acoustic differences. Here we examine seven contemporary models of LSO neurons with different levels of biophysical complexity, from predominantly functional ones (‘shot-noise’ models) to those with more detailed physiological components (variations of integrate-and-fire and Hodgkin-Huxley-type). These models, calibrated to reproduce known monaural and binaural characteristics of LSO, generate largely similar results to each other in simulating ITD and ILD coding. Our comparisons of physiological detail, computational efficiency, predictive performances, and further expandability of the models demonstrate (1) that the simplistic, functional LSO models are suitable for applications where low computational costs and mathematical transparency are needed, (2) that more complex models with detailed membrane potential dynamics are necessary for simulation studies where sub-neuronal nonlinear

Proteomic and physiological analyses reveal the role of exogenous spermidine on cucumber roots in response to Ca(NO3)2 stress.

PubMed

Du, Jing; Guo, Shirong; Sun, Jin; Shu, Sheng

2018-05-01

The mechanism of exogenous Spd-induced Ca(NO 3 ) 2 stress tolerance in cucumber was studied by proteomics and physiological analyses. Protein-protein interaction network revealed 13 key proteins involved in Spd-induced Ca(NO 3 ) 2 stress resistance. Ca(NO 3 ) 2 stress is one of the major reasons for secondary salinization that limits cucumber plant development in greenhouse. The conferred protective role of exogenous Spd on cucumber in response to Ca(NO 3 ) 2 stress cues involves changes at the cellular and physiological levels. To investigate the molecular foundation of exogenous Spd in Ca(NO 3 ) 2 stress tolerance, a proteomic approach was performed in our work. After a 9 days period of Ca(NO 3 ) 2 stress and/or exogenous Spd, 71 differential protein spots were confidently identified. The resulting proteins were enriched in seven different categories of biological processes, including protein metabolism, carbohydrate and energy metabolism, ROS homeostasis and stress defense, cell wall related, transcription, others and unknown. Protein metabolism (31.2%), carbohydrate and energy metabolism (15.6%), ROS homeostasis and stress defense (32.5%) were the three largest functional categories in cucumber root and most of them were significantly increased by exogenous Spd. The Spd-responsive protein interaction network revealed 13 key proteins, whose accumulation changes could be critical for Spd-induced resistance; all 13 proteins were upregulated by Spd at transcriptional and protein levels in response to Ca(NO 3 ) 2 stress. Furthermore, accumulation of antioxidant enzymes, non-enzymatic antioxidant and polyamines, along with reduction of H 2 O 2 and MDA, were detected after exogenous Spd application during Ca(NO 3 ) 2 stress. The results of these proteomic and physiological analyses in cucumber root may facilitate a better understanding of the underlying mechanism of Ca(NO 3 ) 2 stress tolerance mediated by exogenous Spd.

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

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.

Differential and Conditional Activation of PKC-Isoforms Dictates Cardiac Adaptation during Physiological to Pathological Hypertrophy

PubMed Central

Naskar, Shaon; Datta, Kaberi; Mitra, Arkadeep; Pathak, Kanchan; Datta, Ritwik; Bansal, Trisha; Sarkar, Sagartirtha

2014-01-01

A cardiac hypertrophy is defined as an increase in heart mass which may either be beneficial (physiological hypertrophy) or detrimental (pathological hypertrophy). This study was undertaken to establish the role of different protein kinase-C (PKC) isoforms in the regulation of cardiac adaptation during two types of cardiac hypertrophy. Phosphorylation of specific PKC-isoforms and expression of their downstream proteins were studied during physiological and pathological hypertrophy in 24 week male Balb/c mice (Mus musculus) models, by reverse transcriptase-PCR, western blot analysis and M-mode echocardiography for cardiac function analysis. PKC-δ was significantly induced during pathological hypertrophy while PKC-α was exclusively activated during physiological hypertrophy in our study. PKC-δ activation during pathological hypertrophy resulted in cardiomyocyte apoptosis leading to compromised cardiac function and on the other hand, activation of PKC-α during physiological hypertrophy promoted cardiomyocyte growth but down regulated cellular apoptotic load resulting in improved cardiac function. Reversal in PKC-isoform with induced activation of PKC-δ and simultaneous inhibition of phospho-PKC-α resulted in an efficient myocardium to deteriorate considerably resulting in compromised cardiac function during physiological hypertrophy via augmentation of apoptotic and fibrotic load. This is the first report where PKC-α and -δ have been shown to play crucial role in cardiac adaptation during physiological and pathological hypertrophy respectively thereby rendering compromised cardiac function to an otherwise efficient heart by conditional reversal of their activation. PMID:25116170

The Physiology of Protein S-acylation

PubMed Central

Chamberlain, Luke H.; Shipston, Michael J.

2015-01-01

Protein S-acylation, the only fully reversible posttranslational lipid modification of proteins, is emerging as a ubiquitous mechanism to control the properties and function of a diverse array of proteins and consequently physiological processes. S-acylation results from the enzymatic addition of long-chain lipids, most typically palmitate, onto intracellular cysteine residues of soluble and transmembrane proteins via a labile thioester linkage. Addition of lipid results in increases in protein hydrophobicity that can impact on protein structure, assembly, maturation, trafficking, and function. The recent explosion in global S-acylation (palmitoyl) proteomic profiling as a result of improved biochemical tools to assay S-acylation, in conjunction with the recent identification of enzymes that control protein S-acylation and de-acylation, has opened a new vista into the physiological function of S-acylation. This review introduces key features of S-acylation and tools to interrogate this process, and highlights the eclectic array of proteins regulated including membrane receptors, ion channels and transporters, enzymes and kinases, signaling adapters and chaperones, cell adhesion, and structural proteins. We highlight recent findings correlating disruption of S-acylation to pathophysiology and disease and discuss some of the major challenges and opportunities in this rapidly expanding field. PMID:25834228

H2A-DUBbing the mammalian epigenome: expanding frontiers for histone H2A deubiquitinating enzymes in cell biology and physiology.

PubMed

Belle, Jad I; Nijnik, Anastasia

2014-05-01

Posttranslational modifications of histone H2A through the attachment of ubiquitin or poly-ubiquitin conjugates are common in mammalian genomes and play an important role in the regulation of chromatin structure, gene expression, and DNA repair. Histone H2A deubiquitinases (H2A-DUBs) are a group of structurally diverse enzymes that catalyze the removal ubiquitin from histone H2A. In this review we provide a concise summary of the mechanisms that mediate histone H2A ubiquitination in mammalian cells, and review our current knowledge of mammalian H2A-DUBs, their biochemical activities, and recent developments in our understanding of their functions in mammalian physiology. Copyright © 2014 Elsevier Ltd. All rights reserved.

A role for fruit structure in seed survival and germination of Swartzia langsdorffii Raddi beyond dispersal.

PubMed

Vaz, T A A; Rodrigues-Junior, A G; Davide, A C; Nakamura, A T; Toorop, P E

2018-03-01

Diaspore structure has been hypothesised to play a role in seed viability and/or germination of recalcitrant seeds, especially for Swartzia langsdorffii. Thus, this work aims to (i) investigate the in situ contribution of pericarp and aril on seed viability and germination, and (ii) identify morphoanatomical traits of S. langsdorffii diaspores that allow its desiccation-sensitive seeds to remain viable. The role of the pericarp and aril in seed survival and germination was investigated by placing the whole fruit, whole seeds (arillate seed) and bare seeds (without aril) in soil in the forest understorey, assessing germination, emergence, dead, firm and predated seeds, and water content of pericarps, arils and seeds. Correlation analysis was performed between environmental variables and physiological parameters. Histochemical features of diaspores were also investigated. Pericarp water content fell after several months, while the aril maintained its water content. Seeds did not lose water even without the presence of the pericarp and aril. However, presence of the pericarp promoted seed water content, viability and germination long after dispersal. The embryo had a thickened outer periclinal cell wall. Pericarp and aril are not essential to prevent water loss in seeds, but do help to retain seed moisture, favouring viability maintenance and promoting germination during the rainy season. Morphoanatomical features of seeds are suggested as main factors that reduce water loss. Survival of these desiccation-sensitive seeds upon dispersal during the dry season appears to be facilitated by multiple diaspore features that prevent viability loss. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Physiology in conservation translocations.

PubMed

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

2014-01-01

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

Physiological Sociology. Endocrine Correlates of Status Behaviors,

DTIC Science & Technology

1975-01-01

affiliative bonding. One psychiatric illness which manifests itself in social structural relationships in a profound was is sociopathic behavior. By the...very nature of the sociopathic individual, persons with the disorder display altered social behavior (Robins, 1966). The question as to whether such...Oxford: Oxford University Press, 1971. Goldman, H., Lindner, L., Dinitz, S., and Allen, H. The simple sociopath : Physiologic and sociologic

F-BAR family proteins, emerging regulators for cell membrane dynamic changes-from structure to human diseases.

PubMed

Liu, Suxuan; Xiong, Xinyu; Zhao, Xianxian; Yang, Xiaofeng; Wang, Hong

2015-05-09

Eukaryotic cell membrane dynamics change in curvature during physiological and pathological processes. In the past ten years, a novel protein family, Fes/CIP4 homology-Bin/Amphiphysin/Rvs (F-BAR) domain proteins, has been identified to be the most important coordinators in membrane curvature regulation. The F-BAR domain family is a member of the Bin/Amphiphysin/Rvs (BAR) domain superfamily that is associated with dynamic changes in cell membrane. However, the molecular basis in membrane structure regulation and the biological functions of F-BAR protein are unclear. The pathophysiological role of F-BAR protein is unknown. This review summarizes the current understanding of structure and function in the BAR domain superfamily, classifies F-BAR family proteins into nine subfamilies based on domain structure, and characterizes F-BAR protein structure, domain interaction, and functional relevance. In general, F-BAR protein binds to cell membrane via F-BAR domain association with membrane phospholipids and initiates membrane curvature and scission via Src homology-3 (SH3) domain interaction with its partner proteins. This process causes membrane dynamic changes and leads to seven important cellular biological functions, which include endocytosis, phagocytosis, filopodium, lamellipodium, cytokinesis, adhesion, and podosome formation, via distinct signaling pathways determined by specific domain-binding partners. These cellular functions play important roles in many physiological and pathophysiological processes. We further summarize F-BAR protein expression and mutation changes observed in various diseases and developmental disorders. Considering the structure feature and functional implication of F-BAR proteins, we anticipate that F-BAR proteins modulate physiological and pathophysiological processes via transferring extracellular materials, regulating cell trafficking and mobility, presenting antigens, mediating extracellular matrix degradation, and transmitting

Morphological and Physiological Alteration of Maize Root Architectures on Drought Stress.

USDA-ARS?s Scientific Manuscript database

Drought tolerance is a complex agronomic trait and root characteristics logically play an important role in determining the response of plants to drought stress. Research experiments were conducted to investigate genotypic variations in morphological and physiological responses of roots to drought s...

[The physiology of glucagon-like peptide-1 and its role in the pathophysiology of type 2 diabetes mellitus].

PubMed

Escalada, Francisco Javier

2014-09-01

The hormone glucagon-like peptide-1 (GLP-1) is synthesized and secreted by L cells in the small intestine in response to food ingestion. After reaching the general circulation it has a half-life of 2-3 minutes due to degradation by the enzyme dipeptidyl peptidase-4. Its physiological role is directed to control plasma glucose concentration, though GLP-1 also plays other different metabolic functions following nutrient absorption. Biological activities of GLP-1 include stimulation of insulin biosynthesis and glucose-dependent insulin secretion by pancreatic beta cell, inhibition of glucagon secretion, delay of gastric emptying and inhibition of food intake. GLP-1 is able to reduce plasma glucose levels in patients with type 2 diabetes and also can restore beta cell sensitivity to exogenous secretagogues, suggesting that the increasing GLP-1 concentration may be an useful therapeutic strategy for the treatment of patients with type 2 diabetes. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Recognition of emotions using multimodal physiological signals and an ensemble deep learning model.

PubMed

Yin, Zhong; Zhao, Mengyuan; Wang, Yongxiong; Yang, Jingdong; Zhang, Jianhua

2017-03-01

Using deep-learning methodologies to analyze multimodal physiological signals becomes increasingly attractive for recognizing human emotions. However, the conventional deep emotion classifiers may suffer from the drawback of the lack of the expertise for determining model structure and the oversimplification of combining multimodal feature abstractions. In this study, a multiple-fusion-layer based ensemble classifier of stacked autoencoder (MESAE) is proposed for recognizing emotions, in which the deep structure is identified based on a physiological-data-driven approach. Each SAE consists of three hidden layers to filter the unwanted noise in the physiological features and derives the stable feature representations. An additional deep model is used to achieve the SAE ensembles. The physiological features are split into several subsets according to different feature extraction approaches with each subset separately encoded by a SAE. The derived SAE abstractions are combined according to the physiological modality to create six sets of encodings, which are then fed to a three-layer, adjacent-graph-based network for feature fusion. The fused features are used to recognize binary arousal or valence states. DEAP multimodal database was employed to validate the performance of the MESAE. By comparing with the best existing emotion classifier, the mean of classification rate and F-score improves by 5.26%. The superiority of the MESAE against the state-of-the-art shallow and deep emotion classifiers has been demonstrated under different sizes of the available physiological instances. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

From Discovery to Function: The Expanding Roles of Long NonCoding RNAs in Physiology and Disease

PubMed Central

Sun, Miao

2015-01-01

Long noncoding RNAs (lncRNAs) are a relatively poorly understood class of RNAs with little or no coding capacity transcribed from a set of incompletely annotated genes. They have received considerable attention in the past few years and are emerging as potentially important players in biological regulation. Here we discuss the evolving understanding of this new class of molecular regulators that has emerged from ongoing research, which continues to expand our databases of annotated lncRNAs and provide new insights into their physical properties, molecular mechanisms of action, and biological functions. We outline the current strategies and approaches that have been employed to identify and characterize lncRNAs, which have been instrumental in revealing their multifaceted roles ranging from cis- to trans-regulation of gene expression and from epigenetic modulation in the nucleus to posttranscriptional control in the cytoplasm. In addition, we highlight the molecular and biological functions of some of the best characterized lncRNAs in physiology and disease, especially those relevant to endocrinology, reproduction, metabolism, immunology, neurobiology, muscle biology, and cancer. Finally, we discuss the tremendous diagnostic and therapeutic potential of lncRNAs in cancer and other diseases. PMID:25426780

‘Integrative Physiology 2.0’: integration of systems biology into physiology and its application to cardiovascular homeostasis

PubMed Central

Kuster, Diederik W D; Merkus, Daphne; van der Velden, Jolanda; Verhoeven, Adrie J M; Duncker, Dirk J

2011-01-01

Since the completion of the Human Genome Project and the advent of the large scaled unbiased ‘-omics’ techniques, the field of systems biology has emerged. Systems biology aims to move away from the traditional reductionist molecular approach, which focused on understanding the role of single genes or proteins, towards a more holistic approach by studying networks and interactions between individual components of networks. From a conceptual standpoint, systems biology elicits a ‘back to the future’ experience for any integrative physiologist. However, many of the new techniques and modalities employed by systems biologists yield tremendous potential for integrative physiologists to expand their tool arsenal to (quantitatively) study complex biological processes, such as cardiac remodelling and heart failure, in a truly holistic fashion. We therefore advocate that systems biology should not become/stay a separate discipline with ‘-omics’ as its playing field, but should be integrated into physiology to create ‘Integrative Physiology 2.0’. PMID:21224228

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

PubMed

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

2016-03-01

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

Guards at the gate: physiological and pathological roles of tissue-resident innate lymphoid cells in the lung.

PubMed

Cheng, Hang; Jin, Chengyan; Wu, Jing; Zhu, Shan; Liu, Yong-Jun; Chen, Jingtao

2017-12-01

The lung is an important open organ and the primary site of respiration. Many life-threatening diseases develop in the lung, e.g., pneumonia, asthma, chronic obstructive pulmonary diseases (COPDs), pulmonary fibrosis, and lung cancer. In the lung, innate immunity serves as the frontline in both anti-irritant response and anti-tumor defense and is also critical for mucosal homeostasis; thus, it plays an important role in containing these pulmonary diseases. Innate lymphoid cells (ILCs), characterized by their strict tissue residence and distinct function in the mucosa, are attracting increased attention in innate immunity. Upon sensing the danger signals from damaged epithelium, ILCs activate, proliferate, and release numerous cytokines with specific local functions; they also participate in mucosal immune-surveillance, immune-regulation, and homeostasis. However, when their functions become uncontrolled, ILCs can enhance pathological states and induce diseases. In this review, we discuss the physiological and pathological functions of ILC subsets 1 to 3 in the lung, and how the pathogenic environment affects the function and plasticity of ILCs.

['Anatomia actuosa et apta'. The mechanist 'proto'-physiology of B.S. Albinus].

PubMed

van der Korst, J K

1993-01-01

Already during his tenure as professor of anatomy and surgery (1721-1746) and before he became a professor of physiology and medicine at the University of Leiden, Bernard Siegfried Albinus held private lecture courses on physiology. In these lectures he pleaded for a separation of physiology from theoretical medicine, which was still its customary place in the medical curriculum of the first half of the eighteenth century. According to Albinus, physiology was a science in its own right and should be solely based on the careful observation of forms and structures of the human body. From the 'fabrica', the function ('aptitudo') could be derived by careful reasoning. As shown by a set of lecture notes, which recently came to light, Albinus adhered, initially, to a strictly mechanistic explanatory model, which was almost completely based on the physiological concepts of Herman Boerhaave. However, in contrast to the latter, he even rejected the involvement of chemical processes in digestion. Although his lectures were highly acclaimed as demonstrations of minute anatomy, Albinus met with little or no direct response in regard to his concept of physiology.

Vas deferens neuro-effector junction: from kymographic tracings to structural biology principles.

PubMed

Navarrete, L Camilo; Barrera, Nelson P; Huidobro-Toro, J Pablo

2014-10-01

The vas deferens is a simple bioassay widely used to study the physiology of sympathetic neurotransmission and the pharmacodynamics of adrenergic drugs. The role of ATP as a sympathetic co-transmitter has gained increasing attention and furthered our understanding of its role in sympathetic reflexes. In addition, new information has emerged on the mechanisms underlying the storage and release of ATP. Both noradrenaline and ATP concur to elicit the tissue smooth muscle contractions following sympathetic reflexes or electrical field stimulation of the sympathetic nerve terminals. ATP and adenosine (its metabolic byproduct) are powerful presynaptic regulators of co-transmitter actions. In addition, neuropeptide Y, the third member of the sympathetic triad, is an endogenous modulator. The peptide plus ATP and/or adenosine play a significant role as sympathetic modulators of transmitter's release. This review focuses on the physiological principles that govern sympathetic co-transmitter activity, with special interest in defining the motor role of ATP. In addition, we intended to review the recent structural biology findings related to the topology of the P2X1R based on the crystallized P2X4 receptor from Danio rerio, or the crystallized adenosine A2A receptor as a member of the G protein coupled family of receptors as prototype neuro modulators. This review also covers structural elements of ectonucleotidases, since some members are found in the vas deferens neuro-effector junction. The allosteric principles that apply to purinoceptors are also reviewed highlighting concepts derived from receptor theory at the light of the current available structural elements. Finally, we discuss clinical applications of these concepts. Copyright © 2014 Elsevier B.V. All rights reserved.

Mammalian HspB1 (Hsp27) is a molecular sensor linked to the physiology and environment of the cell.

PubMed

Arrigo, André-Patrick

2017-07-01

Constitutively expressed small heat shock protein HspB1 regulates many fundamental cellular processes and plays major roles in many human pathological diseases. In that regard, this chaperone has a huge number of apparently unrelated functions that appear linked to its ability to recognize many client polypeptides that are subsequently modified in their activity and/or half-life. A major parameter to understand how HspB1 is dedicated to interact with particular clients in defined cellular conditions relates to its complex oligomerization and phosphorylation properties. Indeed, HspB1 structural organization displays dynamic and complex rearrangements in response to changes in the cellular environment or when the cell physiology is modified. These structural modifications probably reflect the formation of structural platforms aimed at recognizing specific client polypeptides. Here, I have reviewed data from the literature and re-analyzed my own studies to describe and discuss these fascinating changes in HspB1 structural organization.

Red palm oil: nutritional, physiological and therapeutic roles in improving human wellbeing and quality of life.

PubMed

Oguntibeju, O O; Esterhuyse, A J; Truter, E J

2009-01-01

The link between dietary fats and cardiovascular disease has created a growing interest in dietary red palm oil research. Also, the link between nutrition and health, oxidative stress and the severity or progression of disease has stimulated further interest in the potential role of red palm oil (a natural antioxidant product) to improve oxidative status by reducing oxidative stress in patients with cardiovascular disease, cancer and other chronic diseases. In spite of its level of saturated fatty acid content (50%), red palm oil has not been found to promote atherosclerosis and/or arterial thrombosis. This is probably due to the ratio of its saturated fatty acid to unsaturated fatty acid content and its high concentration of antioxidants such as beta-carotene, tocotrienols, tocopherols and vitamin E. It has also been reported that the consumption of red palm oil reduces the level of endogenous cholesterol, and this seems to be due to the presence of the tocotrienols and the peculiar isomeric position of its fatty acids. The benefits of red palm oil to health include a reduction in the risk of arterial thrombosis and/or atherosclerosis, inhibition of endogenous cholesterol biosynthesis, platelet aggregation, a reduction in oxidative stress and a reduction in blood pressure. It has also been shown that dietary red palm oil, taken in moderation in animals and humans, promotes the efficient utilisation of nutrients, activates hepatic drug metabolising enzymes, facilitates the haemoglobinisation of red blood cells and improves immune function. This review provides a comprehensive overview of the nutritional, physiological and biochemical roles of red palm oil in improving wellbeing and quality of life.

Structure and function of the interphotoreceptor matrix surrounding retinal photoreceptor cells.

PubMed

Ishikawa, Makoto; Sawada, Yu; Yoshitomi, Takeshi

2015-04-01

The interphotoreceptor matrix (IPM) is a highly organized structure with interconnected domains surrounding cone and rod photoreceptor cells and extends throughout the subretinal space. Based on known roles of the extracellular matrix in other tissues, the IPM is thought to have several prominent functions including serving as a receptor for growth factors, regulating retinoid transport, participating in cytoskeletal organization in surrounding cells, and regulation of oxygen and nutrient transport. In addition, a number of studies suggest that the IPM also may play a significant role in the etiology of retinal degenerative disorders. In this review, we describe the present knowledge concerning the structure and function of the IPM under physiological and pathological conditions. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Sex differences in physiological reactivity to acute psychosocial stress in adolescence.

PubMed

Ordaz, Sarah; Luna, Beatriz

2012-08-01

Females begin to demonstrate greater negative affective responses to stress than males in adolescence. This may reflect the concurrent emergence of underlying differences in physiological response systems, including corticolimbic circuitries, the hypothalamic-pituitary-adrenal axis (HPAA), and the autonomic nervous system (ANS). This review examines when sex differences in physiological reactivity to acute psychosocial stress emerge and the directionality of these differences over development. Indeed, the literature indicates that sex differences emerge during adolescence and persist into adulthood for all three physiological response systems. However, the directionality of the differences varies by system. The emerging corticolimbic reactivity literature suggests greater female reactivity, particularly in limbic regions densely innervated by gonadal hormone receptors. In contrast, males generally show higher levels of HPAA and ANS reactivity. We argue that the contrasting directionality of corticolimbic and peripheral physiological responses may reflect specific effects of gonadal hormones on distinct systems and also sex differences in evolved behavioral responses that demand different levels of peripheral physiological activation. Studies that examine both subjective reports of negative affect and physiological responses indicate that beginning in adolescence, females respond to acute stressors with more intense negative affect than males despite their comparatively lower peripheral physiological responses. This dissociation is not clearly explained by sex differences in the strength of the relationship between physiological and subjective responses. We suggest that females' greater subjective responsivity may instead arise from a greater activity in brain regions that translate stress responses to subjective awareness in adolescence. Future research directions include investigations of the role of pubertal hormones in physiological reactivity across all systems

Sex differences in physiological reactivity to acute psychosocial stress in adolescence

PubMed Central

Ordaz, Sarah; Luna, Beatriz

2012-01-01

Summary Females begin to demonstrate greater negative affective responses to stress than males in adolescence. This may reflect the concurrent emergence of underlying differences in physiological response systems, including corticolimbic circuitries, the hypothalamic—pituitary— adrenal axis (HPAA), and the autonomic nervous system (ANS). This review examines when sex differences in physiological reactivity to acute psychosocial stress emerge and the directionality of these differences over development. Indeed, the literature indicates that sex differences emerge during adolescence and persist into adulthood for all three physiological response systems. However, the directionality of the differences varies by system. The emerging corti-colimbic reactivity literature suggests greater female reactivity, particularly in limbic regions densely innervated by gonadal hormone receptors. In contrast, males generally show higher levels of HPAA and ANS reactivity. We argue that the contrasting directionality of corticolimbic and peripheral physiological responses may reflect specific effects of gonadal hormones on distinct systems and also sex differences in evolved behavioral responses that demand different levels of peripheral physiological activation. Studies that examine both subjective reports of negative affect and physiological responses indicate that beginning in adolescence, females respond to acute stressors with more intense negative affect than males despite their comparatively lower peripheral physiological responses. This dissociation is not clearly explained by sex differences in the strength of the relationship between physiological and subjective responses. We suggest that females' greater subjective responsivity may instead arise from a greater activity in brain regions that translate stress responses to subjective awareness in adolescence. Future research directions include investigations of the role of pubertal hormones in physiological reactivity

Nuclear Receptors in Bone Physiology and Diseases

PubMed Central

Youn, Min-Young; Inoue, Kazuki; Takada, Ichiro; Kouzmenko, Alexander; Kato, Shigeaki

2013-01-01

During the last decade, our view on the skeleton as a mere solid physical support structure has been transformed, as bone emerged as a dynamic, constantly remodeling tissue with systemic regulatory functions including those of an endocrine organ. Reflecting this remarkable functional complexity, distinct classes of humoral and intracellular regulatory factors have been shown to control vital processes in the bone. Among these regulators, nuclear receptors (NRs) play fundamental roles in bone development, growth, and maintenance. NRs are DNA-binding transcription factors that act as intracellular transducers of the respective ligand signaling pathways through modulation of expression of specific sets of cognate target genes. Aberrant NR signaling caused by receptor or ligand deficiency may profoundly affect bone health and compromise skeletal functions. Ligand dependency of NR action underlies a major strategy of therapeutic intervention to correct aberrant NR signaling, and significant efforts have been made to design novel synthetic NR ligands with enhanced beneficial properties and reduced potential negative side effects. As an example, estrogen deficiency causes bone loss and leads to development of osteoporosis, the most prevalent skeletal disorder in postmenopausal women. Since administration of natural estrogens for the treatment of osteoporosis often associates with undesirable side effects, several synthetic estrogen receptor ligands have been developed with higher therapeutic efficacy and specificity. This review presents current progress in our understanding of the roles of various nuclear receptor-mediated signaling pathways in bone physiology and disease, and in development of advanced NR ligands for treatment of common skeletal disorders. PMID:23589826

Vasopressin: physiology, assessment and osmosensation.

PubMed

Bankir, L; Bichet, D G; Morgenthaler, N G

2017-10-01

Vasopressin (AVP) plays a major role in the regulation of water and sodium homeostasis by its antidiuretic action on the kidney, mediated by V2 receptors. AVP secretion is stimulated by a rise in plasma osmolality, a decline in blood volume or stress. V1a receptors are expressed in vascular smooth muscle cells, but the role of vasopressin in blood pressure regulation is still a matter of debate. AVP may also play a role in some metabolic pathways, including gluconeogenesis, through its action on V1a receptors expressed in the liver. It is now understood that thirst and arginine vasopressin (AVP) release are regulated not only by the classical homeostatic, intero-sensory plasma osmolality negative feedback, but also by novel, extero-sensory, anticipatory signals. AVP measurement is time-consuming, and AVP level in the blood in the physiological range is often below the detection limit of the assays. Recently, an immunoassay has been developed for the measurement of copeptin, a fragment of the pre-provasopressin molecule that is easier to measure. It has been shown to be a good surrogate marker of AVP. © 2017 The Association for the Publication of the Journal of Internal Medicine.

Expertise in physiological breech birth: A mixed-methods study.

PubMed

Walker, Shawn; Parker, Pam; Scamell, Mandie

2018-06-01

The safety of vaginal breech birth depends on the expertise of birth attendants, yet the meaning of "expertise" remains unclear and subjectively defined. The objective of this study was to define expertise and the roles experts may play in expanding access to this service. We performed an integrative analysis of two strands of data concerning expertise in physiological breech birth, including the following: survey data from a Delphi study involving 26 very experienced clinicians (mean experience = 135 breech births) and 2 service user representatives, and interviews from a grounded theory study of 14 clinicians more moderately experienced with physiological methods (5-30 upright breech births). Data were pooled and analyzed using constant comparative methods. Expertise is defined by its ongoing function, the generation of comparatively good outcomes, and confidence and competence among colleagues. Although clinical experience is important, expertise is developed and expressed in social clinical roles, which expand as experience grows: clinician, mentor, specialist, and expert. To develop expertise within a service, clinicians who have an interest in breech birth should be supported to perform these roles within specialist teams. Specialist breech teams may facilitate the development of expertise within maternity care settings. Evaluation of expertise based on enablement of women and colleagues, as well as outcomes, will potentially avoid the pitfalls of alienation produced by some forms of specialist authority. © 2017 Wiley Periodicals, Inc.

Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine.

PubMed

Bukovsky, Antonin; Caudle, Michael R; Carson, Ray J; Gaytán, Francisco; Huleihel, Mahmoud; Kruse, Andrea; Schatten, Heide; Telleria, Carlos M

2009-02-13

The immune system plays an important role in immunity (immune surveillance), but also in the regulation of tissue homeostasis (immune physiology). Lessons from the female reproductive tract indicate that immune system related cells, such as intraepithelial T cells and monocyte-derived cells (MDC) in stratified epithelium, interact amongst themselves and degenerate whereas epithelial cells proliferate and differentiate. In adult ovaries, MDC and T cells are present during oocyte renewal from ovarian stem cells. Activated MDC are also associated with follicular development and atresia, and corpus luteum differentiation. Corpus luteum demise resembles rejection of a graft since it is attended by a massive influx of MDC and T cells resulting in parenchymal and vascular regression. Vascular pericytes play important roles in immune physiology, and their activities (including secretion of the Thy-1 differentiation protein) can be regulated by vascular autonomic innervation. In tumors, MDC regulate proliferation of neoplastic cells and angiogenesis. Tumor infiltrating T cells die among malignant cells. Alterations of immune physiology can result in pathology, such as autoimmune, metabolic, and degenerative diseases, but also in infertility and intrauterine growth retardation, fetal morbidity and mortality. Animal experiments indicate that modification of tissue differentiation (retardation or acceleration) during immune adaptation can cause malfunction (persistent immaturity or premature aging) of such tissue during adulthood. Thus successful stem cell therapy will depend on immune physiology in targeted tissues. From this point of view, regenerative medicine is more likely to be successful in acute rather than chronic tissue disorders.

Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine

PubMed Central

Bukovsky, Antonin; Caudle, Michael R.; Carson, Ray J.; Gaytán, Francisco; Huleihel, Mahmoud; Kruse, Andrea; Schatten, Heide; Telleria, Carlos M.

2009-01-01

The immune system plays an important role in immunity (immune surveillance), but also in the regulation of tissue homeostasis (immune physiology). Lessons from the female reproductive tract indicate that immune system related cells, such as intraepithelial T cells and monocyte-derived cells (MDC) in stratified epithelium, interact amongst themselves and degenerate whereas epithelial cells proliferate and differentiate. In adult ovaries, MDC and T cells are present during oocyte renewal from ovarian stem cells. Activated MDC are also associated with follicular development and atresia, and corpus luteum differentiation. Corpus luteum demise resembles rejection of a graft since it is attended by a massive influx of MDC and T cells resulting in parenchymal and vascular regression. Vascular pericytes play important roles in immune physiology, and their activities (including secretion of the Thy-1 differentiation protein) can be regulated by vascular autonomic innervation. In tumors, MDC regulate proliferation of neoplastic cells and angiogenesis. Tumor infiltrating T cells die among malignant cells. Alterations of immune physiology can result in pathology, such as autoimmune, metabolic, and degenerative diseases, but also in infertility and intrauterine growth retardation, fetal morbidity and mortality. Animal experiments indicate that modification of tissue differentiation (retardation or acceleration) during immune adaptation can cause malfunction (persistent immaturity or premature aging) of such tissue during adulthood. Thus successful stem cell therapy will depend on immune physiology in targeted tissues. From this point of view, regenerative medicine is more likely to be successful in acute rather than chronic tissue disorders. PMID:20195382

Physiological roles of STIM1 and Orai1 homologs and CRAC channels in the genetic model organism Caenorhabditis elegans

PubMed Central

Strange, Kevin; Yan, Xiaohui; Lorin-Nebel, Catherine; Xing, Juan

2007-01-01

Summary The nematode Caenorhabditis elegans provides numerous experimental advantages for developing an integrative molecular understanding of physiological processes and has proven to be a valuable model for characterizing Ca2+ signaling mechanisms. This review will focus on the role of Ca2+ release activated Ca2+ (CRAC) channel activity in function of the worm gonad and intestine. Inositol 1,4,5-trisphosphate (IP3)-dependent oscillatory Ca2+ signaling regulates contractile activity of the gonad and rhythmic posterior body wall muscle contraction (pBoc) required for ovulation and defecation, respectively. The C. elegans genome contains a single homolog of both STIM1 and Orai1, proteins required for CRAC channel function in mammalian and Drosophila cells. C. elegans STIM-1 and ORAI-1 are coexpressed in the worm gonad and intestine and give rise to robust CRAC channel activity when coexpressed in HEK293 cells. STIM-1 or ORAI-1 knockdown causes complete sterility demonstrating that the genes are essential components of gonad Ca2+ signaling. Knockdown of either protein dramatically inhibits intestinal cell CRAC channel activity, but surprisingly has no effect on pBoc, intestinal Ca2+ oscillations or intestinal ER Ca2+ store homeostasis. CRAC channels thus do not play obligate roles in all IP3-dependent signaling processes in C. elegans. Instead, we suggest that CRAC channels carry out highly specialized and cell specific signaling roles and that they may function as a failsafe mechanism to prevent Ca2+ store depletion under pathophysiological and stress conditions. PMID:17376526

Integrins in T Cell Physiology

PubMed Central

Alabiso, Oscar; Galetto, Alessandra Silvia; Baldanzi, Gianluca

2018-01-01

From the thymus to the peripheral lymph nodes, integrin-mediated interactions with neighbor cells and the extracellular matrix tune T cell behavior by organizing cytoskeletal remodeling and modulating receptor signaling. LFA-1 (αLβ2 integrin) and VLA-4 (α4β1 integrin) play a key role throughout the T cell lifecycle from thymocyte differentiation to lymphocyte extravasation and finally play a fundamental role in organizing immune synapse, providing an essential costimulatory signal for the T cell receptor. Apart from tuning T cell signaling, integrins also contribute to homing to specific target organs as exemplified by the importance of α4β7 in maintaining the gut immune system. However, apart from those well-characterized examples, the physiological significance of the other integrin dimers expressed by T cells is far less understood. Thus, integrin-mediated cell-to-cell and cell-to-matrix interactions during the T cell lifespan still represent an open field of research. PMID:29415483

Comparison of brain urocortin-3 and corticotrophin-releasing factor for physiological responses in chicks.

PubMed

Ogino, Madoka; Okumura, Aki; Khan, Md Sakirul Islam; Cline, Mark A; Tachibana, Tetsuya

2014-02-10

Corticotrophin-releasing hormone (CRH) plays an important role in response to stress, and exerts a physiological effect via its receptor, CRH receptor type-1 (CRH-R1) and CRH receptor type-2 (CRH-R2) with high affinity to CRH-R1 in mammals. Urocortin-3 (UCN-3), a CRH family peptide, is an endogenous ligand for CRH-R2 in mammals. The physiological roles of UCN-3 and CRH-R2 have been investigated in mammals, although their roles still need to be clarified in chicks (Gallus gallus). Few studies have been performed comparing the physiological responses of CRH and UCN-3 in chicks. Therefore the present study was conducted to investigate the effect of intracerebroventricular (ICV) injection of UCN-3 on food intake, rectal temperature, crop-emptying rate and behaviors in chicks, and to compare these physiological responses with the effects resulting from CRH injection. The ICV injection of 20 and 80 pmol UCN-3 decreased food intake, increased rectal temperature and decreased crop-emptying rate and the results were similar to those achieved with CRH. The injection of both UCN-3 and CRH increased spontaneous activity but the behavioral patterns were different: CRH increased the number of vocalizations while UCN-3 increased the number of jumps, wing-flaps and scratching behaviors. These results suggest that UCN-3 regulates food intake, body temperature, and gastric emptying via the CRH-R2 in the brain of chicks, and these effects were similar to those induced by CRH. Copyright © 2013 Elsevier Inc. All rights reserved.

Grandma's TUM-my Trouble: A Case Study in Renal Physiology and Acid-Base Balance

ERIC Educational Resources Information Center

Massey, Ann T.

2015-01-01

This case study involves the role of the kidneys in regulating blood pH and electrolytes. The case was used near the end of a two-semester Human Anatomy and Physiology course sequence, during the time when renal physiology was under study. Groups of two to three students were given the case and associated information (lab values, etc.). Students…

Multifaceted Role of Neuropilins in the Immune System: Potential Targets for Immunotherapy

PubMed Central

Roy, Sohini; Bag, Arup K.; Singh, Rakesh K.; Talmadge, James E.; Batra, Surinder K.; Datta, Kaustubh

2017-01-01

Neuropilins (NRPs) are non-tyrosine kinase cell surface glycoproteins expressed in all vertebrates and widely conserved across species. The two isoforms, such as neuropilin-1 (NRP1) and neuropilin-2 (NRP2), mainly act as coreceptors for class III Semaphorins and for members of the vascular endothelial growth factor family of molecules and are widely known for their role in a wide array of physiological processes, such as cardiovascular, neuronal development and patterning, angiogenesis, lymphangiogenesis, as well as various clinical disorders. Intriguingly, additional roles for NRPs occur with myeloid and lymphoid cells, in normal physiological as well as different pathological conditions, including cancer, immunological disorders, and bone diseases. However, little is known concerning the molecular pathways that govern these functions. In addition, NRP1 expression has been characterized in different immune cellular phenotypes including macrophages, dendritic cells, and T cell subsets, especially regulatory T cell populations. By contrast, the functions of NRP2 in immune cells are less well known. In this review, we briefly summarize the genomic organization, structure, and binding partners of the NRPs and extensively discuss the recent advances in their role and function in different immune cell subsets and their clinical implications. PMID:29067024

Regulation of chromatin structure in the cardiovascular system.

PubMed

Rosa-Garrido, Manuel; Karbassi, Elaheh; Monte, Emma; Vondriska, Thomas M

2013-01-01

It has been appreciated for some time that cardiovascular disease involves large-scale transcriptional changes in various cell types. What has become increasingly clear only in the past few years, however, is the role of chromatin remodeling in cardiovascular phenotypes in normal physiology, as well as in development and disease. This review summarizes the state of the chromatin field in terms of distinct mechanisms to regulate chromatin structure in vivo, identifying when these modes of regulation have been demonstrated in cardiovascular tissues. We describe areas in which a better understanding of chromatin structure is leading to new insights into the fundamental biology of cardiovascular disease. 

Translational Perspective on the Role of Testosterone in Sexual Function and Dysfunction.

PubMed

Podlasek, Carol A; Mulhall, John; Davies, Kelvin; Wingard, Christopher J; Hannan, Johanna L; Bivalacqua, Trinity J; Musicki, Biljana; Khera, Mohit; González-Cadavid, Nestor F; Burnett, Arthur L

2016-08-01

The biological importance of testosterone is generally accepted by the medical community; however, controversy focuses on its relevance to sexual function and the sexual response, and our understanding of the extent of its role in this area is evolving. To provide scientific evidence examining the role of testosterone at the cellular and molecular levels as it pertains to normal erectile physiology and the development of erectile dysfunction and to assist in guiding successful therapeutic interventions for androgen-dependent sexual dysfunction. In this White Paper, the Basic Science Committee of the Sexual Medicine Society of North America assessed the current basic science literature examining the role of testosterone in sexual function and dysfunction. Testosterone plays an important role in sexual function through multiple processes: physiologic (stimulates activity of nitric oxide synthase), developmental (establishes and maintains the structural and functional integrity of the penis), neural (development, maintenance, function, and plasticity of the cavernous nerve and pelvic ganglia), therapeutically for dysfunctional regulation (beneficial effect on aging, diabetes, and prostatectomy), and phosphodiesterase type 5 inhibition (testosterone supplement to counteract phosphodiesterase type 5 inhibitor resistance). Despite controversies concerning testosterone with regard to sexual function, basic science studies provide incontrovertible evidence for a significant role of testosterone in sexual function and suggest that properly administered testosterone therapy is potentially advantageous for treating male sexual dysfunction. Published by Elsevier Inc.