bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiological ecology of the bloom-forming alga Chrysochromulina breviturrita (Prymnesiophyceae) from lakes influenced by acid precipitation
Authors: Wehr John D. , Brown Lewis M. , O'Grady Kathryn
Published: May 2010

Many soft-water lakes in northeastern North America subject to acid precipitation have been affected by lakewide odours. These odours are associated with blooms consisting of nearly unialgal populations of the greenish gold alga Chrysochromulina breviturrita Nich. (Prymnesiophyceae). The alga was isolated from Cinder Lake (Ontario) into axenic culture and maintained in a chemically defined medium which corresponds to the chemistry of lakes influenced by acid precipitation. The medium which was developed, Muskoka No. 42, is described in detail and compared with the average water chemistry of affected lakes. The pH tolerance range of C. breviturrita was determined to be 4.0–6.9, with an optimum of 5.5–6.9; the alga was unable to survive above neutrality. Additions of [Formula: see text] at 100 μM or greater completely inhibited growth. Nutritional studies suggested an inability to grow on any nitrogen source other than [Formula: see text]. The alga was also found to require the vitamins B12 and thiamine but not biotin. The present results represent the first published study in which a freshwater member of the Prymnesiophyceae has been maintained axenically in a defined medium.
Effect of reciprocal transplanting between extremes of plant zones on morphometric plasticity of five plant species in an Oregon salt marsh
Authors: Seliskar Denise M.
Published: May 2010

Reciprocal transplants of each of five salt marsh plant species were made to determine whether differences in morphology and anatomy between plants at the upper and lower distributional limits of each species were fixed or plastic. At the end of 1 year, Deschampsia cespitosa, Distichlis spicata, Grindelia integrifolia, Jaumea carnosa, and Salicornia virginica all demonstrated morphometric plasticity. Environmental variables were measured to look for correlations between morphological and anatomical changes and environment. Chemical properties of the transplanted soils of D. spicata and of S. virginica became like those of the surrounding soil, while the properties of soil around G. integrifolia and J. carnosa transplants did not change significantly upon being moved. Soil moisture content was always greatest at the lower elevational site and probably accounts for much of the structural change observed in the reciprocal transplants. For example, the increase in the amount of aerenchymatous tissue in S. virginica plants moved to the lower elevational site was most likely caused by the nearly saturated soil at that location.
Light microscopic and polypeptide analyses of sclerotia from mesophilic and psychrophilic pathogenic fungi
Authors: Insell James P. , Huner N. P. A. , Newsted W. Jay , van Huystee R. B.
Published: May 2010

The structure and polypeptide composition of sclerotia of three mesophilic pathogenic fungi, Sclerotinia sclerotiorum, Sclerotium rolfsii, and Botrytis cinerea, and one psychrophilic snow mold, Myriosclerotinia borealis, were compared. The sclerotia of S. sclerotiorum and B. cinerea were black, round, hard structures which were composed of three areas: the rind, the cortex, and the medulla. Both the cortical and medullary areas of these sclerotia exhibited intensely stained inclusions. In contrast, sclerotia of M. borealis were not present as discrete entities but coalesced near the central point of inoculation. These black sclerotial masses were composed of thin-walled, pseudoparenchymal cells tightly packed together to form two distinct areas: a rind and a medullarylike region. No inclusions were evident in the medulla of cells of M. borealis sclerotia. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of sclerotial extracts of mesophilic fungi indicated the presence of major polypeptides. The polypeptide complement of B. cinerea contained a single, major polypeptide with an apparent molecular mass of 33 to 36 kDa. Similarly, sclerotia of S. sclerotiorum contained one major polypeptide of approximately 36 kDa in addition to one minor polypeptide of about 18 kDa. However, sclerotia of S. rolfsii contained a major polypeptide of about 16 kDa. Sclerotia of M. borealis contained a major polypeptide of 32 to 36 kDa and a minor polypeptide of about 16 kDa.
Competitive relations among species from pastures of different ages
Authors: Aarssen L. W. , Turkington Roy
Published: May 2010

All possible pairs of Dactylis glomerate, Holcus lanatus, Lolium perenne, Poa compressa, and Trifolium repens were collected where the species pairs occurred in close proximity in pastures that were 2, 21, and 40 years old. Each clone was grown with its natural neighbouring clone in experimental field plots for a period of 1 year. Differences in competitive relations between two species from pastures of different ages were measured by total mixture yield and component yield quotient, i.e., the yield quotient of the lowest and highest yielding components. Results show that the relative competitive abilities of particular species differ markedly depending on the age of the pasture from which the plants were collected. Very little support is given for the traditional view that selection pressures from competition usually result in the evolution of niche differentiation in the component species of a community. Alternative evolutionary consequences of competition permitting coexistence are discussed.
Growth analysis in common milkweed (Asclepias syriaca)
Authors: Campbell T. A.
Published: May 2010

Effects of 24 or 35 °C under 8- (SD) or 18-h (LD) photoperiods on early growth of common milkweed (Asclepias syriaca L.) were studied in growth chambers. The higher temperature stimulated growth under SD but repressed growth under LD. The lower temperature encouraged root growth under SD whereas the 35 °C treatment promoted basal shoot production under both photoperiods. Effects of 24 and 28 °C on early growth and 32 and 36 °C on regrowth from basal shoots were studied under 16-h photoperiods at photosynthetic photon flux densities (PPFDs) of 110 or 310 μmol∙s−1∙m−2. Dry matter distribution patterns to leaves, stems, and roots at the two PPFDs were similar except that during regrowth under the higher PPFD, distributions to leaves and stems increased markedly and stem growth was apparently favoured over leaf growth. During early growth under the higher PPFD, plants were taller, had a greater leaf area, and produced more dry matter than under the lower PPFD. Further, under the higher PPFD, specific leaf area was lower and during regrowth, leaves were smaller and thicker and the plants produced more dry matter. Leaf areas under the two PPFDs were similar during much of the regrowth period.
Growth response of two varieties of slash pine seedlings to chronic ozone exposures
Authors: Hogsett W. E. , Plocher M. , Wildman V. , Tingey D. T. , Bennett J. P.
Published: May 2010

Two geographical varieties of Pinus elliottii (Engelm.) seedlings, elliottii and densa, were exposed continuously to two daily peak exposure profiles of ozone having 7-h (0900–1600) seasonal means of 0.104 and 0.076 ppm and charcoal-filtered air over a 112-day period. The profiles represented a daily rise and decline of hourly ozone concentration. They were constructed with a daily hourly maximum, which for one profile (0.126 μL/L) exceeded the current ozone standard daily; the standard was not exceeded for the other profile (0.094 μL/L). Destructive harvests at 7-day intervals over the exposure period were employed to assess visible injury and to construct growth curves for stem diameter, plant height, top and root dry weight, and needle number and length. The visible injury was slight, yet all the growth parameters decreased significantly with time and ozone concentration; root growth was the most severely impacted. The observed growth response and visible injury of the two varieties were similar. Seed germination was not affected by ozone exposure.
Association of epidermal lignification with nonhost resistance of cucurbits to fungi
Authors: Hammerschmidt Raymond , Bonnen Alice M. , Bergstrom Gary C. , Baker Karen K.
Published: May 2010

Etiolated seedlings of cucumber, muskmelon, watermelon, pumpkin, and squash were inoculated with Colletotrichum lagenarium (Pass.) Ell. & Halst. race 1, Colletotrichum atramentarium (Berk. & Br.) Taub., or Helminthosporium carbonum Ull. The fungi germinated and produced appressoria equally well on all hosts. Penetrations into host cells, however, were routinely observed only in the interactions of C. lagenarium with cucumber, muskmelon, and watermelon. Histochemical staining of the other host–pathogen interactions (nonhost interactions) revealed that the lack of penetration by fungi into nonhost tissue was associated with the deposition of lignin in the upper and lateral host epidermal cell walls around appressoria. Treatment of the lignified tissues with 0.5 M NaOH or hot ethanol did not alter staining reactions. Treatment with hot aminoethanol, a delignifying agent, did eliminate stainings. Cupric oxide oxidation of lignified epidermal cell walls from each host revealed that each host produced a p-coumaryl-rich, guaiacyl-poor ligninlike material. These results suggest that lignification may be a general nonhost resistance response in the Cucurbitaceae.
Crown architecture, light interception, and stomatal conductance patterns for sympatric deciduous and evergreen species in a forest understory
Authors: Young Donald R.
Published: May 2010

Within a mixed deciduous forest in central Virginia, daily patterns of light interception and stomatal conductance were related to crown architecture for the deciduous Asimina triloba and the evergreen Ilex opaca. For A. triloba, branches were up to 54% longer, the bifurcation ratio was 15% lower, branch internode lengths were 15% greater, and leaf angles were closer to the horizontal plane (9 vs. 22°) than for I. opaca, possibly contributing to a greater percentage of sunlit leaves for A. triloba at 1100 and 1400 (22.4 vs. 10.0 and 30.0 vs. 10.1%, respectively). Maximum stomatal conductances to water vapor diffusion were 4.0 and 4.6 mm∙s−1 for sunlit leaves of A. triloba and I. opaca, respectively. Sunlit and shaded leaf stomatal conductances were similar in A. triloba throughout the day, but in I. opaca, values for sunlit leaves were up to 1.3 mm∙s−1 greater than values measured in shaded leaves. In addition, stomatal conductances for shaded leaves of A. triloba remained approximately 1.0 mm∙s−1 greater than for I. opaca throughout most of the afternoon. Therefore, within a forest understory environment, sympatric deciduous and evergreen species may differ in crown architecture, light interception, and stomatal conductance patterns.
Specific cotton leaf responses to wounding and treatment with cell-free extracts of Aspergillus flavus
Authors: Zeringue Jr. H. J. , Conkerton E. J. , Chapital D. C.
Published: May 2010

When initial true leaves of 1-month postemergence Acala SJ-2 cotton plants were wounded by gentle abrasion, accumulations of ferulic acid (4-hydroxy-3-methoxycinnamic acid) were detected on the 3rd and 4th days after treatment. When similar wounds were immediately treated with cell-free extracts of Aspergillus flavus mycelia, elevated levels of scopoletin (6-methoxy-7-hydroxycoumarin) were produced, beginning 1 day after treatment and continuing for 7 days. Elevated levels of scopoletin were not detected in leaves that were only wounded, and enhanced quantities of ferulic acid were not observed in leaf tissue after wounding and exposure to the fungal extract. Accumulations of these compounds were not apparent in nonwounded controls. The results demonstrate a wound response distinct from the wound – fungal extract reaction.
PLANE SYMMETRIC SOLUTIONS IN f(R) GRAVITY
Authors: SHARIF M. , SHAMIR M. FARASAT
Published: May 2010

The modified theories of gravity, especially the f(R) theory, have attracted much attention in recent years. In this context, we explore static plane symmetric vacuum solutions using the metric approach of this theory. The field equations are solved using the assumption of constant scalar curvature which may be zero or nonzero. We have found a total of three plane symmetric solutions. The correspondence of these solutions with the well-known solutions in General Relativity is given.
THE SCHRÖDINGER PROPAGATOR AS A WAVE FUNCTION OF THE WHEELER–DE WITT EQUATION
Authors: MARTINEZ-MORALES JOSE L.
Published: May 2010

The eigenvalue equation of the dynamical Schrödinger operator in polar coordinates without potential is considered. An integral transformation in terms of the Bessel's functions is suggested as a solution. The eigenvalue equation is simplified to an ordinary equation in the time variable. The Schrödinger propagator is calculated with the solution of the eigenvalue equation, and used to find explicitly the wave function of the Wheeler–de Witt equation that describes gravity plus a perfect fluid.
GENERALIZED DEFORMED HARMONIC OSCILLATORS IN THE FRAMEWORK OF UNIFIED (q; α, β, γ; ν)-DEFORMATION
Authors: BURBAN I. M.
Published: May 2010

The aim of this paper is the study of the generalized deformed quantum oscillators in the framework (q; α, β, γ; ν)-deformed of oscillator algebra. By selecting the special values of deformation parameters, we have separated a generalized deformed oscillator connected with generalized discrete Hermite II polynomials. By these means we have constructed Barut–Girardello type coherent states of this oscillator.

We have found the conditions on the (q; α, β, γ; ν)-deformation parameters at which the free (q; α, β, γ; ν)-deformed oscillator approximate the usual anharmonic oscillator in the homogeneous Kerr medium.
ANALYTIC CORRECTIONS TO THE ELECTROMAGNETIC CASIMIR INTERACTION BETWEEN A SPHERE AND A PLATE AT SHORT DISTANCES
Authors: BORDAG M. , NIKOLAEV V.
Published: May 2010

For the vacuum interaction of a sphere in front of a plane, both obeying conductor boundary conditions, we consider the approximation of small separation. We derive the next-to-leading order of the asymptotic expansion in the separation-to-radius ratio ε. This correction is of order ε. In opposite to the scalar cases it contains also contributions proportional to logarithms in first and second order, ε ln ε and ε( ln ε)2. We compare this result with the available findings of numerical and experimental approaches.
THE THERMAL CASIMIR EFFECT: SATURATION
Authors: SERNELIUS BO E.
Published: May 2010

This article addresses the discrepancies between theoretical and experimental results obtained for the thermal Casimir effect. Here we test the possibility that saturation effects may be the root of the problems. We present graphs that describe the numerical derivations in great detail.
ON THE CASIMIR ENTROPY BETWEEN "PERFECT CRYSTALS"
Authors: HENKEL C. , INTRAVAIA F.
Published: May 2010

We give a re-interpretation of an 'entropy defect' in the electromagnetic Casimir effect. The electron gas in a perfect crystal is an electromagnetically disordered system whose entropy contains a finite Casimir-like contribution. The Nernst theorem (third law of thermodynamics) is not applicable.
THE TRACE ANOMALY AND DYNAMICAL VACUUM ENERGY IN COSMOLOGY
Authors: MOTTOLA EMIL
Published: May 2010

The trace anomaly of conformal matter implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. These poles may be described by a local effective action with massless scalar fields, which couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects at macroscopic scales. In an effective field theory approach, the effective action of the anomaly is an infrared relevant term that should be added to the Einstein-Hilbert action of classical General Relativity to take account of macroscopic quantum effects. The additional scalar degrees of freedom contained in this effective action may be understood as responsible for both the Casimir effect in flat spacetime and large quantum backreaction effects at the horizon scale of cosmological spacetimes. These effects of the trace anomaly imply that the cosmological vacuum energy is dynamical, and its value depends on macroscopic boundary conditions at the cosmological horizon scale, rather than sensitivity to the extreme ultraviolet Planck scale.
RECURSIVE BAYESIAN ESTIMATION IN FORWARD PRICE MODELS IMPLIED BY FAIR PRICING
Authors: EL QALLI YASSINE
Published: May 2010

In this paper we describe a recursive Bayesian algorithm for the estimation of forward price models. The forward price is modeled within the benchmark framework for a forward price volatility function which includes a stochastic variable; a forward price with a liquidly traded maturity. A relationship between the bond price, the spot price and certain forward prices is stated. We set up the stochastic real world dynamics for these discretely compounded market observed forward prices. We propose a dynamic Bayesian estimation algorithm for a Monte Carlo time-discretized version of the resulting forward prices dynamics. The parameter to be estimated is a vector consisting of the forward price volatility parameters and the benchmarked bond price volatility parameters.
PROBABILITY DISTRIBUTION AND OPTION PRICING FOR DRAWDOWN IN A STOCHASTIC VOLATILITY ENVIRONMENT
Authors: YAMAMOTO KYO , SATO SEISHO , TAKAHASHI AKIHIKO
Published: May 2010

This paper studies the probability distribution and option pricing for drawdown in a stochastic volatility environment. Their analytical approximation formulas are derived by the application of a singular perturbation method (Fouque et al., 2000). The mathematical validity of the approximation is also proven. Then, numerical examples show that the instantaneous correlation between the asset value and the volatility state crucially affects the probability distribution and option prices for drawdown.
MONTE CARLO SIMULATIONS FOR THE RISK MANAGEMENT OF ENVIRONMENTAL POLLUTION
Authors: HASSAN OSAMA A. B.
Published: May 2010

This article attempts to adapt the Monte Carlo method to the quantitative risk management of environmental pollution. In this context, the feasibility of stochastic models to quantitatively evaluate the risk of chemical pollution is first discussed and then linked to a case study in which Monte Carlo simulations are applied. The objective of the case study is to develop a Monte Carlo scheme for evaluating the pollution in a lake environment. It is shown that the results can be of interest as they define the risk margins that are important to the sustainability of the ecosystem in general, and human health in particular. Moreover, assessing the environmental pollution with the help of the Monte Carlo method can be feasible and serve the purpose of investigating and controlling the environmental pollution, in the long and short terms.
Control of Actin Filament Treadmilling in Cell Motility
Authors: Bugyi Beáta , Carlier Marie-France
Published: May 2010

Recent advances in structural, biochemical, biophysical, and live cell imaging approaches have furthered our understanding of the molecular mechanisms by which regulated assembly dynamics of actin filaments drive motile processes. Attention is focused on lamellipodium protrusion, powered by the turnover of a branched filament array. ATP hydrolysis on actin is the key reaction that allows filament treadmilling. It regulates barbed-end dynamics and length fluctuations at steady state and specifies the functional interaction of actin with essential regulatory proteins such as profilin and ADF/cofilin. ATP hydrolysis on actin and Arp2/3 acts as a timer, regulating the assembly and disassembly of the branched array to generate tropomyosin-mediated heterogeneity in the structure and dynamics of the lamellipodial network. The detailed molecular mechanisms of ATP hydrolysis/Pi release on F-actin remain elusive, as well as the mechanism of filament branching with Arp2/3 complex or that of the formin-driven processive actin assembly. Novel biophysical methods involving single-molecule measurements should foster progress in these crucial issues.
Actin Dynamics: From Nanoscale to Microscale
Authors: Carlsson Anders E.
Published: May 2010

The dynamic nature of actin in cells manifests itself constantly. Polymerization near the cell edge is balanced by depolymerization in the interior, externally induced actin polymerization is followed by depolymerization, and spontaneous oscillations of actin at the cell periphery are frequently seen. I discuss how mathematical modeling relates quantitative measures of actin dynamics to the rates of underlying molecular level processes. The dynamic properties addressed include the rate of actin assembly at the leading edge of a moving cell, the disassembly rates of intracellular actin networks, the polymerization time course in externally stimulated cells, and spontaneous spatiotemporal patterns formed by actin. Although several aspects of actin assembly have been clarified by increasingly sophisticated models, our understanding of rapid actin disassembly is limited, and the origins of nonmonotonic features in externally stimulated actin polymerization remain unclear. Theory has generated several concrete, testable hypotheses for the origins of spontaneous actin waves and cell-edge oscillations. The development and use of more biomimetic systems applicable to the geometry of a cell will be key to obtaining a quantitative understanding of actin dynamics in cells.
The Distribution and Function of Phosphatidylserine in Cellular Membranes
Authors: Leventis Peter A. , Grinstein Sergio
Published: May 2010

Phosphatidylserine (PS) is the most abundant negatively charged phospholipid in eukaryotic membranes. PS directs the binding of proteins that bear C2 or gamma-carboxyglutamic domains and contributes to the electrostatic association of polycationic ligands with cellular membranes. Rather than being evenly distributed, PS is found preferentially in the inner leaflet of the plasma membrane and in endocytic membranes. The loss of PS asymmetry is an early indicator of apoptosis and serves as a signal to initiate blood clotting. This review discusses the determinants and functional implications of the subcellular distribution and membrane topology of PS.
Protein NMR Using Paramagnetic Ions
Authors: Otting Gottfried
Published: May 2010

Paramagnetic metal ions offer outstanding opportunities for protein studies by nuclear magnetic resonance (NMR) spectroscopy. The paramagnetic effects manifested in the NMR spectra provide powerful restraints for the determination of the three-dimensional structure of proteins, open new possibilities for the analysis of protein-protein and protein-ligand interactions, and offer widely applicable tools for sensitivity enhancement of NMR experiments, resonance assignments, and studies of conformational heterogeneity and exchange. With the advent of new reagents for site-specific labeling of proteins with paramagnetic metal ions, a range of established and new strategies that used to be reserved for metalloproteins is becoming available for NMR spectroscopy of nonmetalloproteins.
Protein Quantitation Using Isotope-Assisted Mass Spectrometry
Authors: Kline Kelli G. , Sussman Michael R.
Published: May 2010

Genetic, chemical, and environmental perturbations can all induce large changes in cellular proteomes, and research aimed at quantifying these changes are an important part of modern biology. Although improvements in the hardware and software of mass spectrometers have produced increased throughput and accuracy of such measurements, new uses of heavy isotope internal standards that assist in this process have emerged. Surprisingly, even complex life forms such as mammals can be grown to near-complete replacement with heavy isotopes of common biological elements such as 15N, and these isotopically labeled organisms provide excellent controls for isolating and identifying experimental variables such as extraction or fractionation efficiencies. We discuss here the theory and practice of these technologies, as well as provide a review of significant recent biological applications.
Methylglyoxal increases cardiomyocyte ischemia-reperfusion injury via glycative inhibition of thioredoxin activity
Authors: Wang Xiao-Liang , Lau Wayne B. , Yuan Yue-Xing , Wang Ya-Jing , Yi Wei , Christopher Theodore A. , Lopez Bernard L. , Liu Hui-Rong , Ma Xin-Liang
Published: May 2010

Diabetes mellitus (DM) is closely related to cardiovascular morbidity and mortality, but the specific molecular basis linking DM with increased vulnerability to cardiovascular injury remains incompletely understood. Methylglyoxal (MG), a precursor to advanced glycation end products (AGEs), is increased in diabetic patient plasma, but its role in diabetic cardiovascular complications is unclear. Thioredoxin (Trx), a cytoprotective molecule with antiapoptotic function, has been demonstrated to be vulnerable to glycative inhibition, but whether Trx is glycatively inhibited by MG, thus contributing to increased cardiac injury, has never been investigated. Cultured H9c2 cardiomyocytes were treated with MG (200 μM) for 6 days. The following were determined pre- and post-simulated ischemia-reperfusion (SI-R; 8 h of hypoxia followed by 3 h of reoxygenation): cardiomyocyte death/apoptosis, Trx expression and activity, AGE formation, Trx-apoptosis-regulating kinase-1 (Trx-ASK1) complex formation, and p38 mitogen-activated protein kinase (MAPK) phosphorylation and activity. Compared with vehicle, MG significantly increased SI-R-induced cardiomyocyte LDH release and apoptosis ( P < 0.01). Prior to SI-R, Trx activity was reduced in MG-treated cells, but Trx expression was increased moderately. Moreover, Trx-ASK1 complex formation was reduced, and both p38 MAPK activity and phosphorylation were increased. To investigate the effects of MG on Trx directly, recombinant human Trx (hTrx) was incubated with MG in vitro. Compared with vehicle, MG incubation markedly increased CML formation (a glycation footprint) and inhibited Trx activity. Finally, glycation inhibitor aminoguanidine administration during MG treatment of cultured cells reduced AGE formation, increased Trx activity, restored Trx-ASK1 interaction, and reduced p38 MAPK phosphorylation and activity, caspase-3 activation, and LDH release ( P < 0.01). We demonstrated for the first time that methylglyoxal sensitized cultured cardiomyocytes to SI-R injury by posttranslational modification of Trx via glycation. Therapeutic interventions scavenging AGE precursors may attenuate ischemic-reperfusion injury in hyperglycemic state diseases such as diabetes.
Reactive Oxygen Species Are Involved in Group I mGluR-Mediated Facilitation of Nociceptive Processing in Amygdala Neurons
Authors: Ji Guangchen , Neugebauer Volker
Published: May 2010

Recent biochemical and behavioral data implicate reactive oxygen species (ROS) in peripheral and spinal pain mechanisms. However, pain-related functions of ROS in the brain and mechanisms of pain-related ROS activation remain to be determined. Our previous studies showed that the amygdala plays a key role in emotional-affective pain responses and pain modulation. Hyperactivity of amygdala neurons in an animal pain model depends on group I metabotropic glutamate receptors (subtypes mGluR1 and mGluR5), but their signaling pathway remains to be determined. Here we tested the hypothesis that activation of group I mGluRs increases nociceptive processing in amygdala neurons through a mechanism that involves ROS. Extracellular single-unit recordings were made from neurons in the laterocapsular division of the central nucleus of the amygdala (CeLC) in anesthetized adult male rats. Administration of a group I mGluR agonist (DHPG) into the CeLC by microdialysis increased the responses to innocuous and noxious somatosensory (knee joint compression) and visceral (colorectal distention [CRD]) stimuli. A ROS scavenger (PBN) and a superoxide dismutase mimetic (TEMPOL) reversed the facilitatory effects of DHPG. An mGluR5 antagonist (MPEP) also inhibited the effects of DHPG on the responses to innocuous and noxious somatosensory and visceral stimuli, whereas an mGluR1 antagonist (LY367385) decreased only the responses to visceral stimulation. The results show for the first time that ROS mediate group I mGluR-induced facilitation of nociceptive processing in amygdala neurons. The antagonist data may suggest differential contributions of subtypes mGluR1 and mGluR5 to the processing of somatosensory and visceral nociceptive information in the amygdala.
Minor Contribution of Principal Excitatory Pathways to Hippocampal LFPs in the Anesthetized Rat: A Combined Independent Component and Current Source Density Study
Authors: Korovaichuk A. , Makarova J. , Makarov V. A. , Benito N. , Herreras O.
Published: May 2010

Analysis of local field potentials (LFPs) helps understand the function of the converging neuronal populations that produce the mixed synaptic activity in principal cells. Recently, using independent component analysis (ICA), we resolved ongoing hippocampal activity into several major contributions of stratified LFP-generators. Here, using pathway-specific LFP reconstruction, we isolated LFP-generators that describe the activity of Schaffer-CA1 and Perforant-Dentate excitatory inputs in the anesthetized rat. First, we applied ICA and current source density analysis to LFPs evoked by electrical subthreshold stimulation of the pathways. The results showed that pathway specific activity is selectively captured by individual components or LFP-generators. Each generator matches the known distribution of axonal terminal fields in the hippocampus and recovers the specific time course of their activation. Second, we use sparse weak electrical stimulation to prime ongoing LFPs with activity of a known origin. Decomposition of ongoing LFPs yields a few significant LFP-generators with distinct spatiotemporal characteristics for the Schaffer and Perforant inputs. Both pathways convey an irregular temporal pattern in bouts of population activity of varying amplitude. Importantly, the contribution of Schaffer and Perforant inputs to the power of raw LFPs in the hippocampus is minor (7 and 5%, respectively). The results support the hypothesis on a sparse population code used by excitatory populations in the entorhino-hippocampal system, and they validate the separation of LFP-generators as a powerful tool to explore the computational function of neuronal circuits in real time.
Global gene expression analysis in nonfailing and failing myocardium pre- and postpulsatile and nonpulsatile ventricular assist device support
Authors: Schwientek Patrick , Ellinghaus Peter , Steppan Sonja , D'Urso Donatella , Seewald Michael , Kassner Astrid , Cebulla Ramona , Schulte-Eistrup Sebastian , Morshuis Michiel , Röfe Daniela , El Banayosy Aly , Körfer Reiner , Milting Hendrik
Published: May 2010

Mechanical unloading by ventricular assist devices (VAD) leads to significant gene expression changes often summarized as reverse remodeling. However, little is known on individual transcriptome changes during VAD support and its relationship to nonfailing hearts (NF). In addition no data are available for the transcriptome regulation during nonpulsatile VAD support. Therefore we analyzed the gene expression patterns of 30 paired samples from VAD-supported (including 8 nonpulsatile VADs) and 8 nonfailing control hearts (NF) using the first total human genome array available. Transmural myocardial samples were collected for RNA isolation. RNA was isolated by commercial methods and processed according to chip-manufacturer recommendations. cRNA were hybridized on Affymetrix HG-U133 Plus 2.0 arrays, providing coverage of the whole human genome Array. Data were analyzed using Microarray Analysis Suite 5.0 (Affymetrix) and clustered by Expressionist software (Genedata). We found 352 transcripts were differentially regulated between samples from VAD implantation and NF, whereas 510 were significantly regulated between VAD transplantation and NF (paired t-test P < 0.001, fold change ≥1.6). Remarkably, only a minor fraction of 111 transcripts was regulated in heart failure (HF) and during VAD support. Unsupervised hierarchical clustering of paired VAD and NF samples revealed separation of HF and NF samples; however, individual differentiation of VAD implantation and VAD transplantation was not accomplished. Clustering of pulsatile and nonpulsatile VAD did not lead to robust separation of gene expression patterns. During VAD support myocardial gene expression changes do not indicate reversal of the HF phenotype but reveal a distinct HF-related pattern. Transcriptome analysis of pulsatile and nonpulsatile VAD-supported hearts did not provide evidence for a pump mode-specific transcriptome pattern.
Elevated myocardial Na+/H+exchanger isoform 1 activity elicits gene expression that leads to cardiac hypertrophy
Authors: Xue Jin , Mraiche Fatima , Zhou Dan , Karmazyn Morris , Oka Tatsujiro , Fliegel Larry , Haddad Gabriel G.
Published: May 2010

In myocardial disease, elevated expression and activity of Na+/H+exchanger isoform 1 (NHE1) are detrimental. To better understand the involvement of NHE1, transgenic mice with elevated heart-specific NHE1 expression were studied. N-line mice expressed wild-type NHE1, and K-line mice expressed activated NHE1. Cardiac morphology, interstitial fibrosis, and cardiac function were examined by histological staining and echocardiography. Differences in gene expression between the N-line or K-line and nontransgenic littermates were probed with genechip analysis. We found that NHE1 K-line (but not N-line) hearts developed hypertrophy, including elevated heart weight-to-body weight ratio and increased cross-sectional area of the cardiomyocytes, interstitial fibrosis, as well as depressed cardiac function. N-line hearts had modest changes in gene expression (50 upregulations and 99 downregulations, P < 0.05), whereas K-line hearts had a very strong transcriptional response (640 upregulations and 677 downregulations, P < 0.05). In addition, the magnitude of expression alterations was much higher in K-line than N-line mice. The most significant changes in gene expression were involved in cardiac hypertrophy, cardiac necrosis/cell death, and cardiac infarction. Secreted phosphoprotein 1 and its signaling pathways were upregulated while peroxisome proliferator-activated receptor γ signaling was downregulated in K-line mice. Our study shows that expression of activated NHE1 elicits specific pathways of gene activation in the myocardium that lead to cardiac hypertrophy, cell death, and infarction.
Isolation of Nebulin from Rabbit Skeletal Muscle and Its Interaction with Actin
Authors: Chitose Ryo , Watanabe Atsushi , Asano Masato , Hanashima Akira , Sasano Kouhei , Bao Yulong , Maruyama Koscak , Kimura Sumiko
Published: May 2010

Nebulin is about 800 kDa filamentous protein that binds the entire thin filament of vertebrate skeletal muscle sarcomeres. Nebulin cannot be isolated from muscle except in a completely denatured form by direct solubilization of myofibrils with SDS because nebulin is hardly soluble under salt conditions. In the present study, nebulin was solubilized by a salt solution containing 1 M urea and purified by DEAE-Toyopearl column chromatography via 4 M urea elution. Rotary-shadowed images of nebulin showed entangled knit-like particles, about 20 nm in diameter. The purified nebulin bound to actin filaments to form loose bundles. Nebulin was confirmed to bind actin,α-actinin,β-actinin, and tropomodulin, but not troponin or tropomyosin. The data shows that full-length nebulin can be also obtained in a functional and presumably native form, verified by data from experiments using recombinant subfragments.
Computing with Biologically Inspired Neural Oscillators: Application to Colour Image Segmentation
Authors: Belatreche Ammar , Maguire Liam , McGinnity Martin , McDaid Liam , Ghani Arfan
Published: May 2010

This paper investigates the computing capabilities and potential applications of neural oscillators, a biologically inspired neural model, to grey scale and colour image segmentation, an important task in image understanding and object recognition. A proposed neural system that exploits the synergy between neural oscillators and Kohonen self-organising maps (SOMs) is presented. It consists of a two-dimensional grid of neural oscillators which are locally connected through excitatory connections and globally connected to a common inhibitor. Each neuron is mapped to a pixel of the input image and existing objects, represented by homogenous areas, are temporally segmented through synchronisation of the activity of neural oscillators that are mapped to pixels of the same object. Self-organising maps form the basis of a colour reduction system whose output is fed to a 2D grid of neural oscillators for temporal correlation-based object segmentation. Both chromatic and local spatial features are used. The system is simulated in Matlab and its demonstration on real world colour images shows promising results and the emergence of a new bioinspired approach for colour image segmentation. The paper concludes with a discussion of the performance of the proposed system and its comparison with traditional image segmentation approaches.
The Immunoexpression of FSH-R in the Ductuli Efferentes and the Epididymis of Men and Rat: Effect of FSH on the Morphology and Steroidogenic Activity of Rat Epididymal Epithelial Cells In Vitro
Authors: Świder-Al-Amawi Małgorzata , Kolasa Agnieszka , Sikorski Andrzej , Marchlewicz Mariola , Baranowska-Bosiacka Irena , Wiszniewska Barbara
Published: May 2010

The Sertoli cells were regarded as the only target for FSH in male reproductive system. The expression of FSH receptor (FSH-R) was detected also in epithelial cells of the caput epididymis of rat and monkey. We showed in the immunohistochemistry study the expression of FSH-R in rat and human ductuli efferentes and the caput, corpus, and cauda epididymis, moreover, by Western blot analysis in the caput and cauda epididymis of rat. Additionally, we presented that the morphology of rat epididymal epithelial cells in vitro was affected by FSH, and FSH stimulation resulted in the increase of 17β-estradiol synthesis by rat caput epididymal cells in dose-depended manner. In conclusion, the identification of FSH receptors in human and rat epididymides supports our results that the epididymis is a target organ not only for LH but additionally for FSH. On the basis of the results we showed for the first time that morphology of epididymal epithelial cells and epididymal steroidogenesis can be regulated by FSH.
Coevolutionary Genetic Algorithms for Establishing Nash Equilibrium in Symmetric Cournot Games
Authors: Protopapas Mattheos K. , Battaglia Francesco , Kosmatopoulos Elias B.
Published: May 2010

We use coevolutionary genetic algorithms to model the players' learning process in several Cournot models and evaluate them in terms of their convergence to the Nash Equilibrium. The “social-learning” versions of the two coevolutionary algorithms we introduce establish Nash Equilibrium in those models, in contrast to the “individual learning” versions which, do not imply the convergence of the players' strategies to the Nash outcome. When players use “canonical coevolutionary genetic algorithms” as learning algorithms, the process of the game is an ergodic Markov Chain; we find that in the “social” cases states leading to NE play are highly frequent at the stationary distribution of the chain, in contrast to the “individual learning” case, when NE is not reached at all in our simulations; and finally we show that a large fraction of the games played are indeed at the Nash Equilibrium.
Ordered Assembly of the Adhesive and Electrochemical Connections within Newly Formed Intercalated Disks in Primary Cultures of Adult Rat Cardiomyocytes
Authors: Geisler Sarah B. , Green Kathleen J. , Isom Lori L. , Meshinchi Sasha , Martens Jeffrey R. , Delmar Mario , Russell Mark W.
Published: May 2010

The intercalated disk (ID) is a complex structure that electromechanically couples adjoining cardiac myocytes into a functional syncitium. The integrity of the disk is essential for normal cardiac function, but how the diverse elements are assembled into a fully integrated structure is not well understood. In this study, we examined the assembly of new IDs in primary cultures of adult rat cardiac myocytes. From 2 to 5 days after dissociation, the cells flatten and spread, establishing new cell-cell contacts in a manner that recapitulates the in vivo processes that occur during heart development and myocardial remodeling. As cells make contact with their neighbors, transmembrane adhesion proteins localize along the line of apposition, concentrating at the sites of membrane attachment of the terminal sarcomeres. Cx43 gap junctions and ankyrin-G, an essential cytoskeletal component of voltage gated sodium channel complexes, were secondarily recruited to membrane domains involved in cell-cell contacts. The consistent order of the assembly process suggests that there are specific scaffolding requirements for integration of the mechanical and electrochemical elements of the disk. Defining the relationships that are the foundation of disk assembly has important implications for understanding the mechanical dysfunction and cardiac arrhythmias that accompany alterations of ID architecture.
Analysis of a Simple Vector‐Host Epidemic Model with Direct Transmission
Authors: Cai Liming , Li Xuezhi
Published: May 2010

Vector‐host epidemic models with direct transmission are proposed and analyzed. It is shown that the stability of the equilibria in the proposed models can be controlled by the basic reproduction number of the disease transmission. One model considers that the dynamics of human hosts and vectors are described by SIS and SI model, respectively, where the global asymptotical stability for the equilibria of the model is analyzed by constructing Lyapunov function, respectively. The other model considers that the dynamics of the human hosts and vectors are described by SIRS and SI model, respectively, where the global stability of the disease‐free equilibrium and the persistence of the disease in the model are also analyzed, respectively.
Organotin Compound Derived from 3‐Hydroxy‐2‐formylpyridine Semicarbazone: Synthesis, Crystal Structure, and Antiproliferative Activity
Authors: Wiecek Joanna , Kovala-Demertzi Dimitra , Ciunik Zbigniew , Wietrzyk Joanna , Zervou Maria , Demertzis Mavroudis A.
Published: May 2010

The novel diphenyltin(IV) compound [Ph2(HyFoSc)Sn] (2), where H2HyFoSc (1) is 3‐hydroxy‐2‐formylpyridine semicarbazone, was prepared and characterized by vibrational and NMR (1H, 13C) spectroscopy. The structure of [Ph2(HyFoSc)Sn] was confirmed by single‐crystal X‐ray crystallography. The doubly deprotonated ligand is coordinated to the tin atom through the enolic‐oxygen, the azomethine‐nitrogen, and phenolic‐oxygen, and so acts as an anionic tridentate ligand with the ONO donors. Two carbon atoms complete the fivefold coordination at the tin(IV) center. Intermolecular hydrogen bonding, C–H → π, and π → π interactions combine to stabilize the crystal structure. Compounds 1 and 2 have been evaluated for antiproliferative activity in vitro against the cells of three human tumor cell lines: MCF‐7 (human breast cancer cell line), T24 (bladder cancer cell line), A549 (nonsmall cell lung carcinoma), and a mouse fibroblast L‐929 cancer cell line.
Integrated Simulation Environment for Unmanned Autonomous Systems—Towards a Conceptual Framework
Authors: Perhinschi M. G. , Napolitano M. R. , Tamayo S.
Published: May 2010

The paper initiates a comprehensive conceptual framework for an integrated simulation environment for unmanned autonomous systems (UAS) that is capable of supporting the design, analysis, testing, and evaluation from a “system of systems” perspective. The paper also investigates the current state of the art of modeling and performance assessment of UAS and their components and identifies directions for future developments. All the components of a comprehensive simulation environment focused on the testing and evaluation of UAS are identified and defined through detailed analysis of current and future required capabilities and performance. The generality and completeness of the simulation environment is ensured by including all operational domains, types of agents, external systems, missions, and interactions between components. The conceptual framework for the simulation environment is formulated with flexibility, modularity, generality, and portability as key objectives. The development of the conceptual framework for the UAS simulation reveals important aspects related to the mechanisms and interactions that determine specific UAS characteristics including complexity, adaptability, synergy, and high impact of artificial and human intelligence on system performance and effectiveness.
Depletion ofDNMT3ASuppressed Cell Proliferation and RestoredPTENin Hepatocellular Carcinoma Cell
Authors: Zhao Zhujiang , Wu Qingxiang , Cheng Jian , Qiu Xuemei , Zhang Jianqiong , Fan Hong
Published: May 2010

Promoter hypermethylation mediated by DNA methyltransferases (DNMTs) is the main reason for epigenetic inactivation of tumor suppressor genes (TSGs). Previous studies showed thatDNMT1andDNMT3Bplay an important role in CpG island methylation in tumorigenesis. Little is known about the role ofDNMT3Ain this process, especially in hepatocellular carcinoma (HCC). In the present study, increasedDNMT3Aexpression in 3 out of 6 HCC cell lines and 16/25 (64%) HCC tissues implied thatDNMT3Ais involved in hepatocellular carcinogenesis. Depletion ofDNMT3Ain HCC cell line SMMC-7721 inhibited cell proliferation and decreased the colony formation (about 65%). Microarray data revealed that 153 genes were upregulated in DNMT3A knockdown cells and that almost 71% (109/153) of them contain CpG islands in their5′region. 13 of them includingPTEN, a crucial tumor suppressor gene in HCC, are genes involved in cell cycle and cell proliferation. Demethylation ofPTENpromoter was observed inDNMT3A-depleted cells implying that DNMT3A silencedPTENvia DNA methylation. These results provide insights into the mechanisms ofDNMT3Ato regulate TSGs by an epigenetic approach in HCC.
Epigenetic Silencing of the Sulfate Transporter Gene DTDST Induces Sialyl Lewisx Expression and Accelerates Proliferation of Colon Cancer Cells
Authors: Yusa Akiko , Miyazaki Keiko , Kimura Naoko , Izawa Mineko , Kannagi Reiji
Published: May 2010

Colon cancer cells express the carbohydrate determinant sialyl Lewisx, while they exhibit markedly decreased the expression of its sulfated derivative, sialyl 6-sulfo Lewisx. In contrast, normal colonic epithelial cells strongly express sialyl 6-sulfo Lewisx, but they virtually do not express sialyl Lewisx. Impaired sulfation was therefore suggested to occur during the course of malignant transformation of colonic epithelial cells and was assumed to be responsible for the increased sialyl Lewisx expression in cancers. To elucidate the molecular biological background of the impaired sulfation in cancers, we studied the expression levels of mRNA for 6-O-sulfotransferase isoenzymes, PAPS synthases and transporters, and a cell membrane sulfate transporter, DTDST, in cancer tissues. The most striking decrease in cancer cells compared with nonmalignant epithelial cells was noted in the transcription of the DTDST gene (P = 0.0000014; n = 20). Most cultured colon cancer cells had a diminished DTDST transcription, which was restored when cultured with histone deacetylase inhibitors. Suppression of DTDST transcription under the control of a tet-off inducible promoter resulted in increased sialyl Lewisx expression and reduced sialyl 6-sulfo Lewisx expression. Unexpectedly, the growth rate of the cancer cells was markedly enhanced when transcription of DTDST was suppressed. These results show that the decrease in the transcription of the sulfate transporter gene is the major cause of decreased expression of sialyl 6-sulfo Lewisx and increased expression of sialyl Lewisx in colon cancers. The results also suggest that the diminished DTDST expression is closely related to enhanced proliferation of cancer cells. Cancer Res; 70(10); 4064–73. ©2010 AACR.